Patent Grant
12050423
The present invention relates to a powder conveying device which conveys powder such as toner and an electrophotographic image forming apparatus such as a printer, a copier, a facsimile and the like having the powder conveying device.
Conventionally, in an electrophotographic image forming apparatus such as a printer, a copier, a facsimile and the like, there can be such a case where a toner image formed on a photosensitive drum, an intermediate transfer belt or the like is not completely transferred to a recording medium such as a sheet, and the toner remains on the photosensitive drum, the intermediate transfer belt or the like. The residual toner remaining on the photosensitive drum, the intermediate transfer belt or the like is removed from the photosensitive drum, the transfer belt or the like by a cleaning unit and is conveyed by a toner conveying unit to a toner accommodating container disposed inside an apparatus main body. Then, when the toner accommodating container is filled with the residual toner, a user replaces the toner containing container with a new toner containing container.
As described in Japanese Patent Application Publication No. 2015-125209, a method of changing drive by using a ratchet mechanism has been conventionally used as a drive method for the toner conveying unit. The ratchet mechanism is constituted by an engagement portion of a drive member (drive component), an engagement portion of a driven member (driven component), and an inclined portion of the driven member. When the drive member rotates forward, each of the engagement portions is engaged with each other and transmits the drive. When the drive member rotates reversely, the engagement portion of the drive member rides over an inclined surface of the inclined portion of the driven member, either one of the drive member and the driven member moves to an axial direction of a rotating axis, and the drive is disengaged. When the drive member drives with the forward rotation again after the reverse rotation, if the member which has moved in the axial direction of the rotating axis is not returned to a position before the movement, the engagement portion of the drive member and the engagement portion of the driven member do not engage with each other and thus, the drive cannot be transmitted. Therefore, the ratchet mechanism which, rotates the drive member forward and reversely and switches the drive, requires a moving member which returns the member which has moved in the axial direction of the rotating axis to the position before the movement. As a method of the moving member, a method is known with which a member is continuously pressed by using a biasing member such as a spring in a direction toward the position before the movement so as to move the member.
When the biasing member is used as the moving member, the member, i.e., either one of the drive member and the driven member, which has moved, is pressed by the biasing member in the direction toward the position before the movement. Here, assume that the driven member moves in the axial direction of the rotating axis. When the driven member moves by pressing by the biasing member from the position after the movement to the position before the movement, a sound of collision between the drive member and the driven member is generated. Since the collision sound is generated at each rotation of the ratchet mechanism particularly in the reverse rotation when the drive is disengaged, the noisy collision sound is not desirable for the user.
Thus, the present invention has an object to provide an art which can reduce a sound during drive in a drive mechanism used in an image forming apparatus.
In order to achieve the above mentioned object, a drive mechanism used in an image forming apparatus of the present invention includes the following:
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Referring to the drawings, forms for carrying out the present invention will be described in detail by way of example on the basis of an embodiment example. Note that dimensions, materials, shapes, relative positioning, and the like of components described in each of embodiments are to be appropriately changed in accordance with configurations of an apparatus and a device to which the invention is applied and various conditions, and are therefore not intended to limit the scope of the invention to the following embodiments.
An image forming apparatus 1 according to an embodiment 1 of the present invention will be described.
Sheet Supply
In a lower part of the image forming apparatus 1, a cassette 2 is accommodated capable of being withdrawn. In the cassette 2, recording materials such as paper, sheet and the like are accommodated. The recording materials are separated and fed one by one by means of rotation of a cassette paper-feed portion 3 disposed in the vicinity of a distal end part of the recording material. After that, they are conveyed by a resist roller 5 to downstream.
Image Forming Portion
The image forming apparatus 1 includes an image forming portion 6 as an image forming unit in which image forming stations 6Y, 6M, 6C, 6K corresponding to each color of yellow (Y), magenta (M), cyan (C), black (K) aligned in a lateral row. In the image forming portions 6, photosensitive drums 7Y, 7M, 7C, 7K (hereinafter noted as a photosensitive drum 7), which are image carrying members and charging devices 8Y, 8M, 8C, 8K (charging device 8) which uniformly charge a surface of the photosensitive drums 7 are provided. Moreover, in the image forming portions 6, developing apparatuses 9Y, 9M, 9C, 9K (developing apparatus 9) which cause toner to adhere to an electrostatic latent image and develop as a toner image (developer image) are provided. Furthermore, photosensitive-member cleaning blades 10Y, 10M, 10C, 10K (photosensitive-member cleaning blade 10) which remove a residual toner remaining on the photosensitive drum 7 are provided in the image forming portion 6.
In the developing apparatus 9, developing rollers 11Y, 11M, 11C, 11K (developing roller 11) corresponding to each of the colors are provided with a configuration capable of contacting/separation with respect to each of the photosensitive drums 7. By causing the developing roller 11 to contact/separate in accordance with an image which was made an electrostatic latent image, that is, in accordance with presence/absence of necessity of development, a life of the developing roller 11 is improved. And a scanner unit 12 which forms an electrostatic latent image on the photosensitive drum 7 by emitting a laser beam on the basis of image information is provided on a lower part of the image forming portion 6.
The image forming stations 6Y, 6M, 6C, 6K are constituted capable of attachment/detachment with respect to an apparatus main body of the image forming apparatus 1 as process cartridges. The process cartridge is constituted with the developing apparatus 9 including the developing roller 11 and a photosensitive-member unit including the photosensitive drum 7, the charging device 8, and the photosensitive-member cleaning blade 10 individually or the both of them integrally, capable of attachment/detachment with respect to the apparatus main body.
In this embodiment, the developing apparatus 9 has its own toner accommodation chamber and is constituted such that a toner supplied from a replenishing toner container (toner cartridge) 13 as an accommodating portion is replenished to the toner accommodating chamber. Here, the apparatus main body of the image forming apparatus 1 refers to a constituting part excluding the configuration capable of attachment/detachment with respect to the image forming apparatus 1 such as the process cartridges, the replenishment toner container 13 and the like described above.
Transfer
Above the developing apparatus 9, an intermediate transfer unit 16 is provided. The intermediate transfer unit 16 is disposed substantially horizontally with a side (primary transfer portion 20 side) opposing each of the image forming stations (image forming portions) 6 downward. An intermediate transfer belt 18 opposing each of the photosensitive drums 7 is a rotatable endless belt and is stretched between a plurality of stretching rollers. On an inner surface side of the intermediate transfer belt 18, primary transfer rollers 19Y, 19M, 19C, 19K (primary transfer roller 19) are disposed as primary transfer members. Each of the primary transfer rollers 19 is disposed at a position forming primary transfer portions 20Y, 20M, 20C, 20K (primary transfer portion 20) with each of the photosensitive drums 7 through the intermediate transfer belt 18, respectively. By means of the primary transfer roller 19 to which a voltage is applied in each of the primary transfer portions 20, a toner image is transferred from each of the photosensitive drums 7 to the intermediate transfer belt 18. In this embodiment, a unit including the intermediate transfer belt 18, the plurality of stretching rollers between which the intermediate transfer belt 18 is stretched, and each of the primary transfer rollers 19 is constituted as an intermediate transfer unit 16 capable of attachment/detachment with respect to the apparatus main body.
The toner image developed at each of the image forming stations is transferred in the primary transfer portion 20 to the intermediate transfer belt 18, and by continuously transferring each color, the toner image formed in four colors is formed on a surface of the intermediate transfer belt 18, and it is conveyed to a secondary transfer portion 17.
A secondary transfer roller 21, which is a secondary transfer member, contacts the intermediate transfer belt 18 and forms the secondary transfer portion 17 together with a roller on an opposed side through the intermediate transfer belt 18. In the secondary transfer portion 17, the toner image having been transferred onto the intermediate transfer belt 18 is secondarily transferred to the recording material. The toner which has not been completely transferred to the recording material in the secondary transfer and remained on the intermediate transfer belt 18 is removed by a cleaning unit 22. The toner having been removed by the cleaning unit 22 is conveyed to a toner collecting container 24 via a collected-toner conveying portion 23 and is accumulated. The toner which has not been completely transferred to the intermediate transfer belt 18 on the photosensitive drum 7 is conveyed to the collected-toner conveying portion 23 via a cartridge collected-toner conveying portion 29 and is conveyed to the toner collecting container 24.
Fixation, Paper Discharge
The recording material on which an unfixed toner image has been transferred is further conveyed to downstream, pressurized and heated by a heating unit 25a and a pressurizing roller 25b of a fixing apparatus 25, and the toner image is fixed on the recording material by melting of the toner. After that, the recording material is conveyed to a discharge roller pair 26 and is discharged onto a paper-discharge tray 27. Image formation on the surface of the recording material is performed by this series of operations.
Toner Replenishment
Below the image forming portion 6 and between the scanner unit 12 and the cassette 2, replenishment toner containers 13Y, 13M, 13C, 13K (replenishment toner container 13) which replenish a toner to each of the image forming stations (image forming portions) 6 are attachably and detachably disposed substantially horizontally. The replenishment toner container 13 is also called a toner replenishment cartridge and accommodates a toner. Inside the replenishment toner container 13 is filled with a toner for replenishment corresponding to each of the colors. The toner conveying devices 14Y, 14M, 14C, 14K (toner conveying device 14) convey toner received from the replenishment toner container 13 upward in accordance with toner consumption in the image forming portion 6 and supply the toner to the developing apparatus 9. The toner conveying device 14 conveys the toner to be used for image formation. The toner conveying device 14 as a toner conveying portion is driven by toner-conveying drive devices 15Y, 15M, 15C, 15K (toner-conveying drive device 15) as drive units disposed on a lower part of the toner conveying device 14. The toner-conveying drive device 15 includes a motor as a power source for providing a drive force for driving each screw of the toner conveying device 14 to the toner conveying device 14, a gear as a drive transmitting unit and the like.
Power-Supply Device
On a rear surface side of the image forming apparatus 1, a low-voltage power-supply device (not shown) which supplies a voltage to various motors (including a motor M, which will be described later), a fan, and a control portion such as a solenoid and the like provided in the image forming apparatus 1 is disposed. Moreover, in a space between the intermediate transfer belt 18 and the toner collecting container 24, a high-voltage power-supply device 28 which applies a high voltage to the charging device 8, the developing apparatus 9, the primary transfer roller 19, the secondary transfer roller 21 and the like is disposed.
Toner Collecting Unit into Toner Collecting Container
The toner collecting container 24 forms an internal space as an accommodating portion which collects the toner by connecting the collecting-container upper part 24a and a collecting-container lower part 24b with each other. The toner collecting container 24 includes a toner supply port 30 which receives the toner conveyed by the collected-toner conveying portion 23 (see
The internal space of the toner collecting container 24 is divided into a first accommodating chamber 33 and a second accommodating chamber 34 by a partition 35. In the partitioned internal spaces, the one with a smaller capacity is the second accommodating chamber 34, and the internal space other than the second accommodating chamber 34 is the first accommodating chamber 33. In the partition 35, a communication port 36 through which the first accommodating chamber 33 and the second accommodating chamber 34 communicate with each other is disposed. Below the toner supply port 30, a first screw 31 as a toner conveying member is disposed. At a position aligned in parallel with the first screw 31, a second screw 32, which is a rotatably supported rotating body, is disposed. The first screw 31 and the second screw 32 extend in a horizontal direction in the internal space of the toner collecting container 24, respectively. The second screw 32 is longer in a direction of a rotation axis than the first screw 31 and extends to a vicinity of a center of the first accommodating chamber 33. A position of the communication port 36 is located on a side opposite to the second screw 32 with the first screw 31 as a reference. On a downstream of the second screw 32, a lever 37, which is a detecting member interlocking with the second screw 32 is disposed.
Ratchet Mechanism
A configuration of a ratchet mechanism 40, which is a feature of this embodiment, will be explained. The first screw 31 couples with a drive transmission gear 38, and the first screw 31 is driven by driving the drive transmission gear 38 by a drive portion (not shown) including the motor M, which is a DC brushless motor, for example, as a drive source. A driven gear 39 is supported rotatably around a rotation axis O and is driven by engaging with the drive transmission gear 38. The second screw 32 is supported rotatably around the rotation axis O and is driven by coupling with the driven gear 39 through the ratchet mechanism 40, which is a rotation regulating unit.
The drive member 50 is engaged with the driven gear 39 and rotates in an H direction as a first rotating direction around a rotation axis coaxially with the rotation axis O of the driven gear 39 by receiving a drive force from the driven gear 39. The drive member 50 is a cylindrical member. The coupling member 51 is disposed such that a part (insertion portion 51f) on the upstream side in a toner conveying direction F along the rotation axis O is accommodated in an inner cylinder portion of the drive member 50. On the downstream side in the toner conveying direction F of the coupling member 51, a drive transmitting portion for transmitting a drive force to the second screw 32 is provided. The coupling member 51 is supported rotatably around the rotation axis coaxially with the drive member 50 and movably between a first engagement position and a second engagement position, which will be described later, along the rotation axis direction. On the upstream side in the toner conveying direction F with respect to the coupling member 51, the spring 52 as the biasing member is provided between the drive member 50 and the coupling member 51. The coupling member 51 is biased (pressed) by a biasing force (elastic force) of the spring 52 toward the second screw 32 side, that is, the downstream side in the toner conveying direction F along the rotation axis O. This biasing direction is a direction from the second engagement position (position away from the second screw 32) toward the first engagement position (position close to the second screw 32) as a first axis direction.
The drive member 50 has an opening portion 50f in the cylinder portion, and a coupling-side engagement portion of the coupling member 51 having a rib-shaped protruding portion protruding in a radial direction from an outer peripheral surface of the insertion portion 51f of the coupling member 51 inserted into the cylinder portion of the drive member 50 is inserted to the opening portion 50f. That is, the coupling-side engagement portion of the coupling member 51 is opposed to an end surface of the opening portion 50f of the drive member 50 in a circumferential direction around the rotation axis of the drive member 50 and a direction along the rotation axis direction of the drive member 50. This end surface of the opening portion 50f of the drive member 50 functions as a drive-side engagement portion 501 (first engagement portion), that is, as various contact portions 501a to 501e, which will be described later. On the other hand, the coupling member 51 has, as the above mentioned protruding portion, an engagement rib 51a having a first contacted portion 511a, a second contacted portion 511b, a third contacted portion 511c, and a fourth contacted portion 511d constituted as the various contacted portions capable of contacting the contact portions 501a to 501e.
The drive member 50 has the first contact portion 501a to be engaged with the coupling member 51 as the first contact portion of the drive-side engagement portion 501. The coupling member 51 has the engagement rib 51a to be engaged with the drive member 50 as the coupling-side engagement portion (second engagement portion). The first contact portion 501a of the drive member 50 and the first contacted portion 511a of the engagement rib 51a of the coupling member 51 engage with each other in the H direction so that the coupling member 51 is rotated/driven by the drive member 50 in the H direction.
The coupling member 51 has a protruding portion 51e as a drive transmitting portion, extending to the downstream side in the toner conveying direction F, on the downstream side in the toner conveying direction F. A side surface on the downstream side in the H direction of the protruding portion 51e is a coupling-side inclined surface 51b as a drive inclined surface inclined such that the farther it extends toward the downstream side in the toner conveying direction F, it extends toward a J direction as a second rotation direction in a direction opposite to the H direction. A side surface on the downstream side in the J direction of the protruding portion 51e is a coupling-side side surface 51d extending along the rotation axis O.
The second screw 32 has a rotating-side inclined surface 32a as a first drive transmitted portion. The rotating-side inclined surface 32a is an inclined surface inclined such that the farther it extends toward the upstream side in the toner conveying direction F as a second axis direction, it extends toward the H direction. When the coupling member 51 is at the first engagement position, the coupling-side inclined surface 51b is opposed to the rotating-side inclined surface 32a of the second screw 32 in the H direction. When the coupling member 51 is rotated in the H direction by being driven by the drive member 50, the coupling-side inclined surface 51b and the rotating-side inclined surface 32a contact each other. When the rotating-side inclined surface 32a and the coupling-side inclined surface 51b contact each other in a state where the coupling member 51 is pressed to the second screw 32 side by the spring 52, a force by the spring 52 works between the inclined surfaces. The coupling member 51 is constituted to be maintained at the first engagement position while a reaction force that the coupling-side inclined surface 51b receives from the rotating-side inclined surface 32a is smaller than a biasing force of the spring 52 acting on the coupling member 51, while when the reaction force becomes larger than the biasing force, the coupling member moves to the second engagement position. That is, if the force required for the second screw 32 to be driven is smaller than the force working between the inclined surfaces by the spring 52, the second screw 32 is driven by the coupling member 51.
By using
When the toner reaches the second screw 32 disposed and aligned in parallel with the first screw 31, it is conveyed by the rotation of the second screw 32 in an arrow F direction to a vicinity of the center in the first accommodating chamber 33. The toner having been conveyed by the second screw 32 spreads concentrically and collects in the first accommodating chamber 33 from a screw end 32f of the second screw 32, as indicated by a broken line in
By using
When the force required for driving the second screw 32 exceeds the force by the spring 52, as shown in
When the second screw 32 is stopped, the lever 37 interlocking with the second screw 32 is also stopped. A detecting method when the lever 37 is stopped is such that, when there is no switching between shielding and transmission in a detection result of the photosensor 41 within time of one rotation of the second screw 32, it is determined to be stop. Since the stop of the lever 37 means that the toner collects in the first accommodating chamber 33, it is notified to a user that a replacement timing of the toner collecting container 24 is coming soon (hereinafter, it is described as a replacement advance notice). By giving the replacement advance notice to the user, a period for preparation of the new toner collecting container 24 can be provided.
In this embodiment, it is configured such that a rib shape of the engagement rib 51a is provided in the coupling member 51, and the first contact portion 501a or the second contact portion 501b is provided in the drive member 50 so that they are engaged with each other, but it may have such a relationship that the rib shape is provided in the drive member 50, and the coupling member 51 has two contact portions. Moreover, in this embodiment, the coupling-side inclined surface 51b of the coupling member 51 and the rotating-side inclined surface 32a of the second screw 32 do not have to be complete inclined surfaces but may be curved surfaces having large curvatures as long as they can be driven by the contact between the surfaces, and the effect of this embodiment is not lost.
Here, when the coupling member 51 comes to the second engagement position, it does not return to the first engagement position even if it continuously rotates in the H direction.
The drive member 50 has the fourth contact portion 501d opposed to the third contacted portion 511c of the engagement rib 51a in the J direction and capable of engagement when the coupling member 51 is at the second engagement position. Moreover, the drive member 50 has the drive-portion inclined surface 501e as a fifth contact portion opposed to the third contacted portion 511c of the engagement rib 51a in the J direction and capable of engagement when the coupling member 51 is at the first engagement position. The drive-portion inclined surface 501e is an inclined surface inclined so as to extend toward the J direction as it extends toward the downstream side in the toner conveying direction F, that is, an inclined surface inclined such that an upstream end in the toner conveying direction F is an upstream end in the J direction and a downstream end in the toner conveying direction F is a downstream end in the J direction. The engagement rib 51a has the fourth contacted portion 511d, which is an engagement inclined surface inclined so as to extend toward the J direction as it extends toward the downstream side in the toner conveying direction F, on the downstream side in the H direction opposed to the fourth contact portion 501d and the drive-portion inclined surface 501e (downstream side in the H direction of the third contacted portion 511c). The second screw 32 has a rotating-side side surface 32e as a second drive transmitted portion, capable of contacting the coupling-side side surface 51d of the protruding portion 51e in the H direction and extending along the rotation axis O, when the coupling member 51 is at the first engagement position, and the drive member 50 rotates in the J direction.
When the drive member 50 rotates in the J direction in a state where the coupling member 51 is at the first engagement position, first, the fourth contact portion 501d and the fourth contacted portion 511d of the engagement rib 51a contact and engage with each other. As the result of this engagement, the coupling member 51 rotates in the J direction by the drive force received from the drive member 50. When it further rotates in the J direction from the state shown in
As described above, by using the configuration of driving/coupling of the ratchet mechanism 40 for the configuration illustrated in this embodiment, the sound generated in the ratchet mechanism 40 can be reduced. That is, it is so configured that periodic collisions between the coupling member and the driven member generated during idling of the coupling member in the non-drive transmitted state in the conventional ratchet mechanism is not generated in the ratchet mechanism 40 of this embodiment. Moreover, it is also configured such that an impact of a collision between the coupling member and the driven member generated at the switching from the non-drive transmitted state to the drive transmitted state is alleviated by providing the inclined surface on the contact portion in the ratchet mechanism 40 of this embodiment. Therefore, generation of an impact sound during an operation of the ratchet mechanism 40 is suppressed, and the image forming apparatus 1 whose noise is reduced can be provided to the user.
A typical configuration to which the drive transmission mechanism of the present invention is applied is a powder conveying device which conveys a powder such as a toner as a developer in the image forming apparatus, but the present invention may be also applied to the other drive transmitting portions in the image forming apparatus.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2021-205742, filed on Dec. 20, 2021, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-205742 | Dec 2021 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 9098019 | Ishido | Aug 2015 | B2 |
| 10527969 | Williamson | Jan 2020 | B1 |
| 20050163530 | Miller | Jul 2005 | A1 |
| 20060062600 | Chang | Mar 2006 | A1 |
| 20120328336 | Ota | Dec 2012 | A1 |
| 20160070199 | Oh | Mar 2016 | A1 |
| 20180348698 | Tamaki | Dec 2018 | A1 |
| 20210018865 | Matsumoto | Jan 2021 | A1 |
| 20210026296 | Takahashi | Jan 2021 | A1 |
| Number | Date | Country |
|---|---|---|
| H05224568 | Sep 1993 | JP |
| H10220550 | Aug 1998 | JP |
| 2012008381 | Jan 2012 | JP |
| 2015125209 | Jul 2015 | JP |
| 2021018359 | Feb 2021 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20230195016 A1 | Jun 2023 | US |
