Drive mechanism and image forming apparatus

Abstract

To provide a technique that can reduce sound in driving in a driving mechanism used in an image forming apparatus.SOLUTION: In a driving mechanism 40, a drive-side engagement part of a driving member 50 comprises: a first contact part 501a that can be in contact with a connection-side engagement part 51a when the driving member 50 rotates in a first rotation direction when a connection member 51 is at a first position; a second contact part 501b that can be in contact with the connection-side engagement part 51a when the driving member 50 rotates in the first rotation direction when the connection member 51 is at a second position; and a third contact part 501c that can be in contact with the connection member 51 to regulate the connection-side engagement part 51a from moving from the second position to the first position when the connection member 51 is at the second position and the driving member 50 rotates in the first rotation direction to bring the second contact part 501b and the connection member 51 into contact with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a powder transport device for transporting powder such as toner, and to an electrophotographic image forming apparatus, such as a printer, a copying machine, or a facsimile machine, that has the powder transport device. [Background technology]

[0002] In conventional electrophotographic image forming devices such as printers, copiers, and facsimiles, a toner image formed on a photosensitive drum or intermediate transfer belt may not be completely transferred to a recording medium such as paper, resulting in residual toner remaining on the photosensitive drum or intermediate transfer belt. Residual toner remaining on the photosensitive drum or intermediate transfer belt is removed from the photosensitive drum or transfer belt by a cleaning device and then transported to a toner container located inside the device body by a toner transport device. When the toner container becomes full of residual toner, a user replaces the toner container with a new one.

[0003] As described in Patent Document 1, a method of changing the drive force using a ratchet mechanism has been conventionally used to drive a toner conveying device. The ratchet mechanism is composed of an engaging portion of a driving member (driving component), an engaging portion of a driven member (driven component), and an inclined portion of the driven component. When the driving member rotates forward, the respective engaging portions engage to transmit the drive force. When the driving member rotates reversely, the engaging portion of the driving member rides up the slope of the inclined portion of the driven component, causing either the driving member or the driven member to move axially along the rotation axis, resulting in loss of drive force. When the driving member rotates forward again after rotating reversely, the member that moved axially along the rotation axis must be returned to its original position before the movement, otherwise the engaging portion of the driving member and the engaging portion of the driven member will not engage, and drive force cannot be transmitted. Therefore, a ratchet mechanism that rotates the driving member forward and backward and switches the drive force requires a moving means to return the member that moved axially along the rotation axis to its original position. As a moving means, a method is known in which a biasing means such as a spring is used to continuously press the member in a direction toward the position before the movement, thereby moving the member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-125209 Summary of the Invention [Problem to be solved by the invention]

[0005] When a biasing means is used as the moving means, the moved member, either the driving member or the driven member, is pressed by the biasing means in a direction toward its original position. Here, let's assume that the driven member moves in the axial direction of the rotation shaft. When the driven member is moved from its original position to its original position by the pressure of the biasing means, a collision sound is generated between the driving member and the driven member. The collision sound is generated every time the ratchet mechanism rotates once, particularly during reverse rotation when the drive is turned off, and a loud collision sound is undesirable for the user.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a technique capable of reducing the noise generated during operation of a drive mechanism used in an image forming apparatus. [Means for solving the problem]

[0007] In order to achieve the above object, the drive mechanism of the present invention comprises: A drive mechanism used in an image forming apparatus, a rotatable driving member having a driving side engaging portion; a connecting member having a connection side engaging portion that engages with the drive side engaging portion and a drive transmission portion, the connecting member being rotatable by receiving a driving force from the drive member at the connection side engaging portion, and being movable between a first position and a second position in the rotational axis direction of the drive member; a biasing means disposed between the drive member and the connecting member in the rotational axis direction and configured to bias the connecting member from the second position toward the first position; a driven member having a first drive transmitted portion that can come into contact with the drive transmitter portion that moves along the first rotation direction when the connecting member is at the first position and the driving member rotates in the first rotation direction, and configured to be rotatable in the first rotation direction by receiving a driving force from the connecting member at the first drive transmitted portion; Equipped with The drive side engagement portion is a first contact portion that can come into contact with the connecting side engaging portion when the drive member rotates in the first rotation direction while the connecting member is in the first position; a second contact portion that can come into contact with the connecting side engaging portion when the drive member rotates in the first rotation direction while the connecting member is in the second position; a third abutment portion that can abut against the connection-side engaging portion so as to restrict movement of the connection member from the second position to the first position in the rotational axis direction when the connection member is at the second position and the drive member rotates in the first rotational direction so that the second abutment portion and the connection member are in a state of abutment; The present invention is characterized by comprising: In order to achieve the above object, the image forming apparatus of the present invention comprises: an image forming unit that forms an image on a recording material using toner; a container having a storage portion for storing toner; To transport the toner contained in the container of Screw and a driving device of the present invention that rotationally drives the screw as the driven member; The present invention is characterized by comprising: [Effects of the Invention]

[0008] As described above, according to the present invention, the drive mechanism of an image forming apparatus can be made quieter with a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing details of a ratchet mechanism according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a main cross-sectional view of the overall configuration of an image forming apparatus according to a first embodiment of the present invention, viewed from the front. [Figure 3] FIG. 1 is a main cross-sectional view of the overall configuration of an image forming apparatus according to a first embodiment of the present invention, viewed from the left side; [Figure 4] FIG. 1 is a diagram illustrating an overall configuration of a toner recovery unit according to a first embodiment of the present invention. [Figure 5] FIG. 1 is a diagram illustrating an overall configuration of a toner recovery unit according to a first embodiment of the present invention. [Figure 6] FIG. 1 is an explanatory diagram of a toner detection mechanism according to a first embodiment of the present invention. [Figure 7] FIG. 1 is an explanatory diagram of a toner detection mechanism according to a first embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing a toner collection process in the first embodiment of the present invention. [Figure 9] FIG. 10 is a diagram showing a toner collection process in the first embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing a toner collection process in the first embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing how toner accumulates in the first embodiment of the present invention. [Figure 12] FIG. 10 is an explanatory diagram of the behavior of the ratchet mechanism during reverse rotation in the first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, with reference to the drawings, a detailed description will be given of an embodiment of the present invention. Note that the dimensions, materials, shapes, and relative positions of the components described in the embodiment may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. In other words, it is not intended to limit the scope of the present invention to the following embodiment. do not have.

[0011] Example 1 An image forming apparatus 1 according to a first embodiment of the present invention will be described. Fig. 2 is a principal cross-sectional view of the overall configuration of the image forming apparatus 1 as seen from the front of the image forming apparatus 1. Fig. 3 is a principal cross-sectional view of the overall configuration of the image forming apparatus 1 as seen from the left of the image forming apparatus 1. With respect to the orientation of the image forming apparatus 1 shown in the drawings, the up-down direction is the direction of gravity, and the left-right direction and the front-rear direction are horizontal directions. Figs. 2 and 3 show the configuration of the image forming apparatus 1 in a state in which the image forming apparatus 1 is placed on a horizontal installation surface, which is a normally assumed installation state, and the left-right direction on the paper corresponds to the horizontal direction, and the up-down direction on the paper corresponds to the up-down direction of the apparatus.

[0012] (Paper feeding) A cassette 2 is housed in the lower part of the image forming apparatus 1 and can be pulled out. Recording materials such as paper or sheets are stored in the cassette 2. The recording materials are separated and fed one by one by the rotation of a cassette paper feed unit 3 arranged near the leading edge of the recording materials. They are then transported downstream by registration rollers 5.

[0013] (Image forming section) The image forming apparatus 1 includes an image forming unit 6, which serves as an image forming means, and is configured by arranging image forming stations 6Y, 6M, 6C, and 6K, each corresponding to a different color—yellow (Y), magenta (M), cyan (C), and black (K)—in a horizontal row. The image forming unit 6 includes photosensitive drums 7Y, 7M, 7C, and 7K (hereinafter referred to as photosensitive drums 7) as image carriers, and charging devices 8Y, 8M, 8C, and 8K (charging devices 8) that uniformly charge the surfaces of the photosensitive drums 7. The image forming unit 6 also includes developing devices 9Y, 9M, 9C, and 9K (developing devices 9) that apply toner to the electrostatic latent images and develop them into toner images (developer images). The image forming unit 6 also includes photosensitive cleaning blades 10Y, 10M, 10C, and 10K (photosensitive cleaning blades 10) that remove residual toner remaining on the photosensitive drums 7.

[0014] The developing device 9 is provided with developing rollers 11Y, 11M, 11C, and 11K (developing rollers 11) corresponding to the respective colors, configured to be able to contact and separate from the respective photosensitive drums 7. The developing rollers 11 are brought into contact with and separated from each other in accordance with the electrostatic latent image, i.e., depending on whether development is required, thereby improving the life of the developing rollers 11. A scanner unit 12 is provided below the image forming section 6 and irradiates a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 7.

[0015] The image forming stations 6Y, 6M, 6C, and 6K are configured as process cartridges that are detachably attached to the main body of the image forming apparatus 1. The process cartridges are configured so that the developing device 9 having the developing roller 11 and the photosensitive unit having the photosensitive drum 7, the charging device 8, and the photosensitive cleaning blade 10 can be detachably attached to the main body of the image forming apparatus 1, either individually or as a whole.

[0016] In this embodiment, the developing device 9 has its own toner storage chamber, and the toner storage chamber is replenished with toner supplied from a supply toner container (toner cartridge) 13 serving as a storage unit. Here, the device body of the image forming apparatus 1 refers to the components excluding components that are detachable from the image forming apparatus 1, such as the process cartridge and supply toner container 13 described above.

[0017] (Transcript) An intermediate transfer unit 16 is provided above the developing device 9. The intermediate transfer belt 18 is disposed substantially horizontally with the side facing each image forming station (image forming unit) 6 (the primary transfer unit 20 side) facing downward. The intermediate transfer belt 18, which faces each photosensitive drum 7, is a rotatable endless belt that is stretched over multiple tension rollers. Primary transfer rollers 19Y, 19M, 19C, and 19K (primary transfer rollers 19) are disposed on the inner surface of the intermediate transfer belt 18 as primary transfer members. Each primary transfer roller 19 is disposed at a position that forms a primary transfer unit 20Y, 20M, 20C, or 20K (primary transfer unit 20) with each photosensitive drum 7 via the intermediate transfer belt 18. At each primary transfer unit 20, a toner image is transferred from each photosensitive drum 7 to the intermediate transfer belt 18 by the primary transfer roller 19 to which a voltage is applied. In this embodiment, a unit including the intermediate transfer belt 18, multiple tension rollers that stretch the intermediate transfer belt 18, and each primary transfer roller 19 is configured as an intermediate transfer unit 16 that is detachable from the device main body.

[0018] The toner images developed at each image forming station are transferred to the intermediate transfer belt 18 at the primary transfer unit 20, and by successively transferring each color, a toner image consisting of four colors is formed on the surface of the intermediate transfer belt 18, and then transported to the secondary transfer unit 17.

[0019] A secondary transfer roller 21, which is a secondary transfer member, contacts the intermediate transfer belt 18 and forms a secondary transfer section 17 with an opposing roller via the intermediate transfer belt 18. The toner image transferred onto the intermediate transfer belt 18 at the secondary transfer section 17 is secondarily transferred onto a recording material. Toner that was not completely transferred to the recording material during the secondary transfer and remains on the intermediate transfer belt 18 is removed by a cleaning unit 22. The toner removed by the cleaning unit 22 is transported to a toner recovery container 24 via a recovered toner transport section 23 and accumulated therein. Toner that was not completely transferred onto the intermediate transfer belt 18 from the photosensitive drum 7 is transported to the recovered toner transport section 23 via a cartridge recovered toner transport section 29, and then transported to the toner recovery container 24.

[0020] (fixing, paper ejection) The recording material onto which the unfixed toner image has been transferred is transported further downstream and is heated and pressurized by a heating unit 25a and a pressure roller 25b of a fixing device 25, causing the toner to melt and fix the toner image to the recording material. The recording material is then transported to a pair of discharge rollers 26 and discharged onto a paper discharge tray 27. Through this series of operations, an image is formed on the surface of the recording material.

[0021] (Toner replenishment) Below the image forming unit 6, between the scanner unit 12 and the cassette 2, replenishment toner containers 13Y, 13M, 13C, and 13K (replenishment toner containers 13) are detachably and substantially horizontally arranged to replenish toner to each image forming station (image forming unit) 6. The replenishment toner containers 13, also called toner replenishment cartridges, contain toner. The replenishment toner containers 13 are filled with replenishment toner corresponding to each color. The toner conveying devices 14Y, 14M, 14C, and 14K (toner conveying devices 14) convey the toner received from the replenishment toner containers 13 upward and supply it to the developing device 9 in accordance with the toner consumption in the image forming unit 6. The toner conveying device 14 conveys the toner used in image formation. The toner conveying device 14, which serves as a toner conveying unit, is driven by toner conveying drive devices 15Y, 15M, 15C, and 15K (toner conveying drive devices 15) which serve as driving means and are disposed below the toner conveying device 14. The toner transport driving device 15 includes a motor as a power source for providing the toner transport device with the driving force for driving each screw of the toner transport device , and gears as a drive transmission means.

[0022] (power supply) On the rear side of the image forming apparatus 1, there is a low-voltage power supply device (not shown) that supplies voltage to various motors (including a motor M described later), fans, solenoids, and other control units provided in the image forming apparatus 1. ) are arranged in the space between the intermediate transfer belt 18 and the toner recovery container 24. A high-voltage power supply 28 is arranged in the space between the intermediate transfer belt 18 and the toner recovery container 24 to apply high voltage to the charging device 8, the developing device 9, the primary transfer roller 19, the secondary transfer roller 21, etc.

[0023] (Means for collecting toner into the toner collection container) Fig. 4(a) is a plan view of the toner recovery container 24 as seen from above. Fig. 4(b) is a perspective view of the toner recovery container 24 as seen from diagonally above. Fig. 5(a) is a plan view of the toner recovery container 24 with the collection container top 24a removed as seen from above. Fig. 5(b) is a perspective view of the toner recovery container 24 with the collection container top 24a removed as seen from diagonally above.

[0024] The toner recovery container 24 has an internal space as a storage section for recovering toner by connecting the upper and lower collection container sections 24a and 24b. The toner recovery container 24 has a toner supply port 30 in the upper collection container section 24a for receiving the toner transported by the collected toner transport section 23 (see FIG. 3) into the internal space.

[0025] The internal space of the toner recovery container 24 is divided by a partition 35 into a first storage chamber 33 and a second storage chamber 34. The smaller of the divided internal spaces is referred to as the second storage chamber 34, and the remaining internal space is referred to as the first storage chamber 33. The partition 35 is provided with a communication port 36 that connects the first storage chamber 33 and the second storage chamber 34. A first screw 31 serving as a toner transport unit is disposed below the toner supply port 30. A second screw 32, a rotatably supported rotating body, is disposed parallel to the first screw 31. The first screw 31 and the second screw 32 each extend horizontally within the internal space of the toner recovery container 24. The second screw 32 is longer in the direction of the rotation axis than the first screw 31 and extends to near the center of the first storage chamber 33. The communication port 36 is located on the opposite side of the second screw 32 relative to the first screw 31. A lever 37, which is a detection means interlocked with the second screw 32, is disposed downstream of the second screw 32.

[0026] 6(a) and 6(b) are enlarged plan views illustrating the behavior of the lever 37, and FIG. 7 is an enlarged perspective view of the photosensor 41 and the vicinity of the lever 37. The photosensor 41 is supported by the image forming apparatus 1 (not shown). The lever 37 moves back and forth between a position where it blocks the optical axis 41a of the photosensor 41 and a position where it does not block the optical axis 41a of the photosensor 41 and allows light to pass through. The lever 37 rotates around the lever center 37a and moves back and forth. For the sake of explanation, FIGS. 6(a) and 6(b) show the state where the collection container top 24a is removed. When the second screw 32 rotates once, the lever 37 moves back and forth once.

[0027] (ratchet mechanism) The configuration of the ratchet mechanism 40, which is a feature of this embodiment, will be described. The first screw 31 is connected to a drive transmission gear 38, and the first screw 31 is driven by driving the drive transmission gear 38 with a drive unit (not shown) including a motor M, such as a DC brushless motor, as a drive source. The driven gear 39 is supported rotatably about a rotation axis O, and is driven by meshing with the drive transmission gear 38. The second screw 32 is supported rotatably about the rotation axis O, and is driven by being connected to the driven gear 39 via a ratchet mechanism 40, which is a rotation restriction means.

[0028] 1(a) is a detailed diagram showing the configuration of a ratchet mechanism 40 serving as a drive mechanism in this embodiment. The ratchet mechanism 40 is made up of a drive member (driving component) 50, a connecting member (connecting component) 51, a spring 52 serving as a biasing means, and a rotation-side slope 32a of a second screw 32 serving as a rotating member (rotating component) and a driven member (driven component).

[0029] The driving member 50 engages with the driven gear 39 and receives a driving force from the driven gear 39 to rotate in the direction H, which is a first rotation direction, around a rotation axis coaxial with the rotation axis O of the driven gear 39. The driving member 50 is a cylindrical member. A portion (insertion portion 51f) of the connecting member 51 on the upstream side in the toner transport direction F along the rotation axis O is housed in the inner cylindrical portion of the driving member 50. A drive transmission portion for transmitting a driving force to the second screw 32 is provided on the downstream side of the connecting member 51 in the toner transport direction F. The connecting member 51 is supported so as to be rotatable around the rotation axis coaxial with the driving member 50 and movable along the rotation axis direction between a first engagement position and a second engagement position, which will be described later. A spring 52 serving as a biasing means is provided between the driving member 50 and the connecting member 51 on the upstream side of the connecting member 51 in the toner transport direction F. The connecting member 51 is biased (pressed) by the biasing force (elastic force) of the spring 52 toward the second screw 32, i.e., toward the downstream side in the toner transport direction F along the rotation axis O. This biasing direction is the direction from the second engagement position (position away from the second screw 32) to the first engagement position (position close to the second screw 32) in the first axial direction.

[0030] The driving member 50 has an opening 50f in its cylindrical portion, and a coupling-side engaging portion of the coupling member 51, which has a rib-shaped protrusion protruding radially from the outer circumferential surface of the insertion portion 51f of the coupling member 51 inserted into the cylindrical portion of the driving member 50, is inserted into the opening 50f. That is, the coupling-side engaging portion of the coupling member 51 faces the end face of the opening 50f of the driving member 50 in the circumferential direction around the rotation axis of the driving member 50 and in the direction along the rotation axis direction of the driving member 50. The end face of the opening 50f of the driving member 50 functions as a driving-side engaging portion 501, i.e., various contact portions 501a to 501e, which will be described later. On the other hand, the connecting member 51 has, as the above-mentioned protrusion, an engaging rib 51a having a first abutment portion 511a, a second abutment portion 511b, a third abutment portion 511c, and a fourth abutment portion 511d as various abutment portions configured to be able to abut against the abutment portions 501a to 501e.

[0031] The driving member 50 has a first contact portion 501a that engages with the connecting member 51 as a first contact portion of the driving-side engaging portion 501. The connecting member 51 has an engaging rib 51a that engages with the driving member 50 as a connecting-side engaging portion. The first contact portion 501a of the driving member 50 and the first contacted portion 511a of the engaging rib 51a of the connecting member 51 engage in the H direction, so that the connecting member 51 is driven to rotate in the H direction by the driving member 50.

[0032] The connecting member 51 has a protrusion 51e, which extends downstream in the toner transport direction F, as a drive transmission part on the downstream side in the toner transport direction F. The side surface of the protrusion 51e on the downstream side in the H direction forms a connecting-side inclined surface 51b as a driving inclined surface that slopes toward the J direction, which is a second rotation direction opposite to the H direction, as it approaches the downstream side in the toner transport direction F. The side surface of the protrusion 51e on the downstream side in the J direction forms a connecting-side side surface 51d that extends along the rotation axis O.

[0033] The second screw 32 has a rotation-side inclined surface 32a as a first drive force receiving portion. The rotation-side inclined surface 32a is inclined in the direction H as it moves upstream in the toner transport direction F, which is the second axial direction. When the connecting member 51 is in the first engagement position, the connecting-side inclined surface 51b faces the rotation-side inclined surface 32a of the second screw 32 in the direction H. When the connecting member 51 is driven by the driving member 50 to rotate in the direction H, the connecting-side inclined surface 51b and the rotation-side inclined surface 32a come into contact with each other. When the connecting member 51 is pressed toward the second screw 32 by the spring 52 and the rotation-side inclined surface 32a and the connecting-side inclined surface 51b come into contact with each other, a force from the spring 52 acts between the inclined surfaces. The connecting member 51 is configured to be maintained in the first engagement position while the reaction force that the connecting-side inclined surface 51b receives from the rotation-side inclined surface 32a is smaller than the biasing force of the spring 52 acting on the connecting member 51, and to move to the second engagement position when the reaction force becomes larger than the biasing force. In other words, the force required to drive the second screw 32 is the force acting between the inclined surfaces by the spring 52. If it is smaller, the second screw 32 is driven by the connecting member 51 .

[0034] The behavior of toner in the toner recovery container 24 will be described using Figures 8, 9, and 10. Figure 8 is an enlarged view of the area from the toner supply port 30 to the second screw 32 with the collection container top 24a removed. Figure 9 is a cross-sectional view along line DD with the collection container top 24a attached. Figure 10 is a perspective view of the area inside the toner recovery container 24 shown in Figure 8. Toner supplied from the toner supply port 30 is transported in the direction of arrow A by the rotation of the first screw 31. As the first screw 31 rotates, the toner is transported until it hits the first screw downstream partition 35a and accumulates downstream of the first screw 31. Once accumulated downstream of the first screw 31, the toner moves along the wall of the first screw downstream partition 35a and spreads in the directions of arrows B and C. The communication port 36 of the partition 35 is located above the bottom end of the first screw 31 in the direction of gravity, as indicated by arrow E. As a result, the toner is transported by the rotation of the second screw 32 before the toner surface rises to enter the second storage chamber .

[0035] When the toner reaches the second screw 32, which is arranged parallel to the first screw 31, the rotation of the second screw 32 transports the toner in the direction of arrow F to near the center of the first storage chamber 33. The toner transported by the second screw 32 spreads concentrically from the screw end 32a of the second screw 32 into the first storage chamber 33 and accumulates there, as shown by the dashed lines in FIG.

[0036] 1(a) to 1(d), the behavior of the ratchet mechanism 40 as toner accumulates will be described in chronological order. When there is little toner around the second screw 32 and the force required to drive it is small, as shown in FIG. 1(a), the second screw 32 is driven by the connecting member 51 with the connecting-side slope 51b of the connecting member 51 and the rotation-side slope 32a of the second screw 32 in contact. The position of the connecting member 51 shown in FIG. 1(a) is the first engagement position (first position). As the image forming apparatus 1 continues to be used, the area around the second screw 32 becomes filled with toner, and the force (torque) required to drive the second screw 32 increases.

[0037] When the force required to drive the second screw 32 exceeds the force of the spring 52, the coupling-side inclined surface 51b moves along the rotation-side inclined surface 32a, as shown in FIG. 1(b). Further driving causes the coupling member 51 to move until the coupling-member flat surface 51c contacts the rotor flat surface 32b, as shown in FIG. 1(c). The position of the coupling member 51 shown in FIG. 1(c) is the second engagement position (second position). In the second engagement position, the coupling-side inclined surface 51b and the rotation-side inclined surface 32a do not come into contact, and therefore the force of the spring 52 is not applied to the rotation-side inclined surface 32a. Therefore, the coupling member 51 does not apply a driving force to the second screw 32, and the rotation of the second screw 32 stops. When the driving member 50 rotates in the direction of arrow H in the second engagement position, the second abutment portion 501b of the driving member 50 and the first abutted portion 511a of the engagement rib 51a of the connecting member 51 abut and engage with each other, causing the connecting member 51 to rotate.

[0038] 1(d) shows the state when the connecting member 51 rotates from the state shown in FIG. 1(c) and the connecting-side inclined surface 51b rotates to the phase of the rotor groove portion 32c. The connecting member 51 is pressed toward the second screw 32 by the biasing force of the spring 52, and therefore moves toward the second screw 32. The movement of the connecting member 51 is restricted at a position where the second abutted portion 511b of the engaging rib 51a contacts the drive member flat portion 501c, which serves as the third abutment portion of the drive member 50. The drive member flat portion 501c is a circumferentially extending surface disposed to face the engaging rib 51a in the second axial direction when the connecting member 51 is in the second engagement position and the drive member 50 rotates in the H direction so that the second abutment portion 501b engages with the first abutted portion 511a of the connecting member 51. The drive member flat portion 501c can be engaged with the connecting member 51 so as to restrict the movement of the connecting member 51 to the first engagement position. The connecting member 51 has a gap k between the second abutted portion 511b of the engaging rib 51a and the drive member flat portion 501c at the second engagement position. The projection 51e moves by a distance equal to the distance k. This gap k is set to be smaller than the stroke amount in the direction of the rotation axis required for the coupling-side inclined surface 51b of the projection 51e to contact the rotation-side inclined surface 32a. Therefore, when the coupling member 51 is in the second engagement position and in a non-drive-transmitting state, the coupling-side inclined surface 51b does not come into contact with the rotation-side inclined surface 32a when the coupling member 51 and the second screw 32 rotate idly. Alternatively, the degree of contact between the coupling-side inclined surface 51b and the rotation-side inclined surface 32a is smaller than the degree of contact when the coupling member 51 is in the first engagement position and in a drive-transmitting state. This prevents or reduces the generation of a collision sound due to contact between the coupling-side inclined surface 51b and the rotation-side inclined surface 32a. Since reducing the gap k reduces the collision sound during movement, it is desirable to make the gap between the second abutted portion 511b of the engagement rib 51a and the drive-member flat surface 501c as small as possible when the coupling member 51 is in the second engagement position. The gap k is formed when the connecting member flat surface 51c and the rotor flat surface 32b abut against each other, but it is desirable to make part of the rotor flat surface 32b inclined so that the gap k gradually decreases, which can further reduce the impact noise.

[0039] When the second screw 32 stops, the lever 37, which moves in conjunction with the second screw 32, also stops. When the lever 37 stops, it is determined that the second screw 32 has stopped if the detection result of the photosensor 41 does not switch between light blocking and light transmitting within the time it takes for the second screw 32 to make one rotation. When the lever 37 stops, this means that toner has accumulated in the first storage chamber 33, and the user is notified that it is soon time to replace the toner collection container 24 (hereinafter referred to as a replacement advance notice). By notifying the user of the replacement advance notice, a period of time can be set aside for the user to prepare a new toner collection container 24.

[0040] In this embodiment, the connecting member 51 is provided with a rib shape of the engagement rib 51a, and the drive member 50 is provided with a first abutment portion 501a or a second abutment portion 501b, which are engaged with each other, but it is also possible to provide a rib shape on the drive member 50 and have two abutment portions on the connecting member 51. Also, in this embodiment, even if the connecting-side inclined surface 51b of the connecting member 51 and the rotation-side inclined surface 32a of the second screw 32 are not completely inclined surfaces but are curved surfaces with a large curvature, the effect of this embodiment is not lost as long as they can be driven by surface-to-surface contact.

[0041] Here, once the connecting member 51 reaches the second engagement position, it will not return to the first engagement position even if it continues to rotate in the direction H. Figures 12(a) and 12(b) show the behavior of the connecting member 51 when it is rotated in the direction J, which is opposite to the direction H, from the position shown in Figure 1(d) to move the connecting member 51 from the second engagement position to the first engagement position.

[0042] The driving member 50 has a fourth contact portion 501d that faces the third contact portion 511c of the engaging rib 51a in the J direction and is engageable with it when the connecting member 51 is in the second engagement position. The driving member 50 also has a driving portion inclined surface 501e as a fifth contact portion that faces the third contact portion 511c of the engaging rib 51a in the J direction and is engageable with it when the connecting member 51 is in the first engagement position. The driving portion inclined surface 501e is an inclined surface that slopes in the J direction as it approaches the downstream side of the toner transport direction F, i.e., an inclined surface that slopes in such a way that its upstream end in the toner transport direction F becomes the upstream end in the J direction and its downstream end in the toner transport direction F becomes the downstream end in the J direction. The engaging rib 51a has a fourth contacted portion 511d, which is an engaging slope that slopes in the J direction as it approaches the downstream side in the toner transport direction F, on the downstream side in the H direction (downstream side in the H direction of the third contacted portion 511c) facing the fourth contact portion 501d and the driving portion sloped surface 501e. The second screw 32 has a rotation-side side surface 32e as a second drive transmitted portion that extends along the rotation axis O and is capable of coming into contact in the H direction with the connecting-side side surface 51d of the protrusion 51e when the connecting member 51 is in the first engagement position and the driving member 50 rotates in the J direction.

[0043] When the drive member 50 rotates in the J direction while the connecting member 51 is in the first engagement position, the fourth contact portion 501d and the fourth contacted portion 511d of the engaging rib 51a first come into contact with each other and engage with each other. Due to this engagement, the connecting member 51 rotates in the direction J due to the driving force received from the driving member 50. When the connecting member 51 further rotates in the direction J from the state shown in FIG. 12(a) and the connecting-side inclined surface 51b rotates to the rotor groove portion 32c, the connecting member 51 is pressed toward the second screw 32 by the biasing force of the spring 52, and the connecting member 51 moves to the first engaging position shown in FIG. 1(a). During this movement, as shown in FIG. 12(b), the fourth abutted portion 511d of the engaging rib 51a and the driving-part inclined surface 501e come into contact with each other. Because the fourth abutted portion 511d of the engaging rib 51a and the driving-part inclined surface 501e are in contact with each other as inclined surfaces inclined with respect to the rotation axis direction as described above, the impact noise when the connecting member 51 returns to the first engaging position is reduced. Furthermore, when the connecting member 51 subsequently moves further downstream in the toner transport direction F, the sliding of the inclined surfaces causes the connecting member 51 to gradually move closer to the second screw 32, thereby reducing the collision noise between the protrusion 51e and the rotor groove portion 32c.

[0044] As described above, by using the drive coupling configuration of the ratchet mechanism 40 described in this embodiment, it is possible to reduce the noise generated by the ratchet mechanism 40. That is, the periodic collisions that occur between the connecting member and the driven member when the connecting member rotates freely in the non-drive transmission state in conventional ratchet mechanisms are prevented by the ratchet mechanism 40 of this embodiment. Furthermore, even in the case of collisions between the connecting member and the driven member that occur when switching from the non-drive transmission state to the drive transmission state, the ratchet mechanism 40 of this embodiment is configured with an inclined surface at the contact portion to mitigate the impact of the collision. Therefore, the generation of impact noise during operation of the ratchet mechanism 40 is suppressed, and a quieter image forming apparatus 1 can be provided to the user.

[0045] A typical configuration to which the drive transmission mechanism of the present invention is applied is a powder conveying device that conveys powder such as toner as a developer in an image forming apparatus, but it may also be applied to other drive transmission parts in an image forming apparatus. [Explanation of symbols]

[0046] 32...second screw, 32a...rotation side inclined surface, 39...driven gear, 40...ratchet mechanism, 50...driving member, 501...driving side engaging portion, 501a...first contact portion, 501b...second contact portion, 501c...third engaging portion, 501d...fourth contact portion, 501e...fifth contact portion, 51...connecting member, 51a...engaging rib, 51b...connecting side inclined surface, 52...urging means

Claims

1. A drive mechanism used in an image forming apparatus, a rotatable driving member having a driving side engaging portion; a connecting member having a connection side engaging portion that engages with the drive side engaging portion and a drive transmission portion, the connecting member being rotatable by receiving a driving force from the drive member at the connection side engaging portion, and being movable between a first position and a second position in the rotational axis direction of the drive member; a biasing means disposed between the drive member and the connecting member in the direction of the rotation axis, the biasing means biasing the connecting member from the second position toward the first position; a driven member having a first drive transmitted portion that can come into contact with the drive transmitter portion that moves along the first rotation direction when the connecting member is at the first position and the driving member rotates in the first rotation direction, and configured to be rotatable in the first rotation direction by receiving a driving force from the connecting member at the first drive transmitted portion; Equipped with The drive side engagement portion is a first contact portion that can come into contact with the connecting side engaging portion when the drive member rotates in the first rotation direction while the connecting member is in the first position; a second contact portion that can come into contact with the connecting side engaging portion when the drive member rotates in the first rotation direction while the connecting member is in the second position; a third abutment portion that can abut against the connection-side engaging portion so as to restrict movement of the connection member from the second position to the first position in the rotational axis direction when the connection member is at the second position and the drive member rotates in the first rotational direction so that the second abutment portion and the connection member are in a state of abutment with each other; A drive mechanism comprising:

2. The drive side engagement portion is a fifth contact portion that can come into contact with the connecting side engaging portion when the drive member rotates in a second rotation direction that is opposite to the first rotation direction while the connecting member is in the first position; 2. The drive mechanism according to claim 1, further comprising: a fourth abutment portion that can abut against the connection side engagement portion when the drive member rotates in the second rotation direction while the connection member is in the second position.

3. 3. The drive mechanism of claim 2, wherein when the drive member rotates in the second rotation direction while the connecting member is in the second position, the connecting side engagement portion receives a driving force from the fourth abutment portion or the fifth abutment portion to rotate in the second rotation direction, and moves from the second position to the first position due to the biasing force of the biasing means.

4. 4. The drive mechanism according to claim 3, wherein the driven member has a second drive-transmitted portion that can come into contact with the drive transmission portion when the connecting member is in the first position and the driving member rotates in the second rotational direction, and is rotatable in the second rotational direction by receiving a driving force from the connecting member at the second drive-transmitted portion.

5. 5. The drive mechanism of claim 3 or 4, wherein the fifth abutment portion is configured with an inclined surface that is inclined such that its upstream end in the direction from the second position to the first position in the rotational axis direction becomes the upstream end in the second rotational direction, and its downstream end in the direction from the second position to the first position becomes the downstream end in the second rotational direction.

6. the connecting-side engaging portion has an abutting portion that abuts against the fifth abutting portion, The drive mechanism according to claim 5 , wherein the contact portion contacts the fifth contact portion when the connecting member moves from the second position to the first position.

7. the driving member is a cylindrical member having an opening that opens to an outer peripheral surface of a cylindrical portion, the connecting member has an insertion portion that is inserted into an inner cylindrical portion of the drive member, and a protrusion that protrudes from an outer peripheral surface of the insertion portion in a radial direction relative to the rotation axis so as to be inserted into the opening, 7. The drive mechanism according to claim 1, wherein the drive-side engaging portion is provided in the opening.

8. the drive transmission portion has a drive inclined surface that is inclined toward a second rotation direction that is opposite to the first rotation direction as it approaches a first axial direction that is a direction along the rotation axis and moves the connecting member from the second position to the first position, the first drive transmitted portion has an inclined surface that is inclined toward the first rotation direction as it moves toward a second axial direction opposite to the first axial direction, The drive mechanism according to any one of claims 1 to 7, wherein when the connecting member is in the first position and the drive member rotates in the first rotation direction, the drive inclined surface is capable of abutting against the inclined surface of the first drive-transmitted part in the first rotation direction.

9. 9. The drive mechanism according to claim 8, wherein the connecting member is maintained at the first position while a reaction force that the driving inclined surface receives from the inclined surface of the first drive-transmitted part is smaller than a biasing force of the biasing means acting on the connecting member, and is configured to move to the second position when the reaction force becomes larger than the biasing force.

10. 10. The drive mechanism according to claim 1, wherein the driven member is a screw for transporting toner.

11. an image forming unit that forms an image on a recording material using toner; a container having a storage portion for storing toner; a screw for conveying the toner contained in the container; a drive mechanism according to any one of claims 1 to 10, which rotationally drives the screw as the driven member; An image forming apparatus comprising:

Images