Patent Grant
10871730
This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2018-220553, filed on Nov. 26, 2018, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
Embodiments of the present disclosure generally relate to a developer container, a developer supply device, a process cartridge, and an image forming apparatus.
There is a known developer container that includes a developer chamber to store a developer, a discharge port to discharge the developer in the developer chamber to a developing device, a developer conveyance path to transport the developer in the developer chamber to the discharge port, a supply port to supply the developer in the developer chamber to the developer conveyance path, a conveyor disposed in the developer conveyance path to transport the developer to the discharge port, a partition between the developer conveyance path and the developer chamber, and a communication port disposed in the partition to communicate between the developer conveyance path and the developer chamber.
Embodiments of the present disclosure describe an improved developer container that includes a developer chamber configured to store a developer, a discharge port configured to discharge the developer in the developer chamber to a developing device, a developer conveyance path configured to transport the developer in the developer chamber to the discharge port, a supply port configured to supply the developer in the developer chamber to the developer conveyance path, a conveyor disposed in the developer conveyance path and configured to transport the developer to the discharge port, a partition between the developer conveyance path and the developer chamber, and a communication port disposed in the partition between the discharge port and the supply port and connecting the developer conveyance path with the developer chamber.
A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. In addition, identical or similar reference numerals designate identical or similar components throughout the several views.
In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that have the same function, operate in a similar manner, and achieve a similar result.
As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
An electrophotographic printer 100 to form an image by an electrophotographic method is described below as an example of an image forming apparatus according to an embodiment of the present disclosure.
The printer 100 illustrated in
Additionally, a toner cartridge 7 serving as a developer container is detachably attached to the process cartridge 1. Inside a container body 22 of the toner cartridge 7, a developer chamber 8 is disposed to store toner as a developer to be supplied to the developing device 4. The toner cartridge 7 according to the present embodiment further includes, as a portion of the toner cartridge 7, a developer collection chamber 9 to collect excess toner removed by the cleaning blade 5.
The printer 100 further includes a sheet feeder 11, a transfer unit 10 to transfer images onto sheets P as transfer media fed by the sheet feeder 11, a fixing device 12 to fix images on the sheets P, and an output device 13 to eject the sheets P outside the printer 100.
The transfer unit 10 includes a transfer roller 14 as a transferor rotatably supported by a transfer frame 30. The transfer roller 14 contacts the photoconductor 2 in a state in which the process cartridge 1 is installed in the printer 100, thereby forming a transfer nip between the transfer roller 14 and the photoconductor 2. Additionally, the transfer roller 14 is electrically connected to a power source and receives a predetermined amount of voltage that is either direct current (DC) voltage, alternating current (AC) voltage, or including both.
The sheet feeder 11 includes a sheet tray 15 to contain sheets P and a sheet feeding roller 16 to feed the sheets P contained in the sheet tray 15. Downstream from the sheet feeding roller 16 in a direction in which the sheet P is transported, a registration roller pair 17 is provided as a timing roller pair to transport the sheet P timely to the transfer nip. It is to be noted that “sheet P” used here includes, in addition to plain paper, thick paper, post cards, envelopes, thin paper, coated paper, art paper, tracing paper, and the like. Additionally, overhead projector (OHP) transparency (OHP sheet or OHP film) may be used as a recording medium.
The fixing device 12 includes a fixing roller 18 serving as a fixing member and a pressure roller 19 serving as a pressure member. The fixing roller 18 is heated by an infrared heater 23 disposed inside the fixing roller 18. The pressure roller 19 is pressed against and contacts the fixing roller 18, and the area or portion of contact between the pressure roller 19 and the fixing roller 18 serves as a fixing nip.
The output device 13 includes an output roller pair 20. An upper face of the printer 100 is partly recessed into an output tray 21, and the sheet P ejected by the output roller pair 20 is stacked on the output tray 21.
With reference to
The electrostatic latent image formed on the photoconductor 2 is developed into a toner image (visible image) with toner deposited by the developing device 4.
As the image formation starts, the transfer roller 14 rotates, and the predetermined voltage, which is either DC voltage, AC voltage, or including both, is applied to the transfer roller 14, thus forming a transfer electrical field between the transfer roller 14 and the photoconductor 2.
In the bottom portion of the printer 100, the sheet feeding roller 16 starts rotating, and the sheet P is fed out from the sheet tray 15. Then, the registration roller pair 17 temporarily stops the sheet P fed by the sheet feeding roller 16.
The registration roller pair 17 starts rotating at a predetermined timing to transport the sheet P to the transfer nip, timed to coincide with the arrival of the toner image on the photoconductor 2. The toner image on the photoconductor 2 is transferred onto the sheet P as the transfer medium by the effect of the transfer electric field. After the transfer process, the cleaning blade 5 removes excess toner, which is not transferred to the sheet P, remaining on the photoconductor 2, and the removed toner is transported to and collected in the developer collection chamber 9.
Subsequently, the sheet P bearing the toner image is transported to the fixing device 12, and the toner image is fixed on the sheet P by the fixing device 12. Then, the sheet P is ejected outside the printer 100 by the output roller pair 20 and stacked on the output tray 21.
A cover 37 closably openable in the direction indicated by double headed arrow A in
As illustrated in
A first agitator 41 and a second agitator 42 as stirrers to stir the toner in the developer chamber 8 are disposed in the developer chamber 8. The first and second agitators 41 and 42 include agitator shafts 41b and 42b and blades 41a and 42a attached to the agitator shafts 41b and 42b, respectively. In the present embodiment, the blades 41a and 42a are made of resin sheet. The first and second agitators 41 and 42 are driven to rotate in the direction indicated by the blank arrows in
A conveying screw 43 as the conveyor is disposed in the developer conveyance path 44. A collection screw 9a to transport toner removed by the cleaning blade 5 into the developer collection chamber 9 is disposed in the developer collection chamber 9.
As illustrated in
The conveying screw 43 penetrates the developer conveyance path 44 and includes a shaft 43b, a first blade 43a1 having a helical shape, and a second blade 43a2 having a helical shape. The first blade 43a1 transports toner from the toner supply port 44b to the toner replenishment port 44a in the direction indicated by arrow B1 in
Further, a communication port 45d connects the developer conveyance path 44 with the developer chamber 8. The communication port 45d is disposed in the partition 45 on the upstream side from the toner replenishment port 44a in the direction of conveyance of the toner as the developer by the first blade 43a1 (hereinafter, referred to as “developer conveyance direction”) and on the downstream side from the toner supply port 44b in the developer conveyance direction (i.e., between the toner supply port 44b and the toner replenishment port 44a).
The communication port 45d is a hole surrounded by a closed rim 45d0. That is, the closed rim 45d0 is present in any direction perpendicular to the direction (i.e., vertical direction in
The length L1 of the toner replenishment port 44a in the developer conveyance direction is shorter than the pitch P of the first blade 43a1 of the conveying screw 43. Further, the length L2 of the communication port 45d in the developer conveyance direction is shorter than the length L1 of the toner replenishment port 44a in the developer conveyance direction. That is, in the present embodiment, the pitch P of the first blade 43a1>the length L1 of the toner replenishment port 44a in the developer conveyance direction>the length L2 of the communication port 45d in the developer conveyance direction.
A drive unit 50 is disposed on one end side of the container body 22 (the left side in
As the driving force is transmitted from the second gear portion 51b to the screw gear 52, the conveying screw 43 is driven to rotate, and toner in the developer chamber 8 is transported to the toner supply port 44b by the first blade 43a1 in the direction indicated by arrow B1 in
Further, a portion of the toner that has not fallen from the toner replenishment port 44a flows back to the toner replenishment port 44a by the second blade 43a2 (in the direction indicated by arrow B2 in
Some comparative toner cartridges do not include the partition 45 at the upper portion of the developer conveyance path 44. The partition 45 is not provided at the upper portion because, when the toner is supplied to the developing device 4 and the volume of the developer in the developing device 4 increases, air is taken into the developing device 4 along with the rotation of a developing roller 4a of the developing device 4, thereby increasing the pressure in the developing device 4 (hereinafter, referred to as “internal pressure”). Since the toner replenishment port 44a communicates with the interior of the developing device 4, the internal pressure reaches to the developer conveyance path 44. When the upper portion of the developer conveyance path 44 is blocked and the developer conveyance path 44 has only the toner replenishment port 44a and the toner supply port 44b as openings, the pressure caused by the conveying screw 43 that transports toner and the internal pressure opposite to the pressure caused by the conveying screw 43 are applied to the toner in the developer conveyance path 44. As a result, high pressure is applied to the toner in the developer conveyance path 44 because of the pressures in opposite directions from both sides.
If high pressure is applied to toner, the toner may agglomerate in the developer conveyance path 44 in a state in which the toner fails to flow easily in the developer conveyance path 44, such as when the toner with physical properties that cause toner particles to agglomerate is used, when the toner is tightened due to vibration caused by transportation, or when the toner stored in a high-temperature and high-humidity environment is used. In a case in which the upper portion of the developer conveyance path 44 is opened without the partition 45 at the upper portion of the developer conveyance path 44, as the toner in the developer conveyance path 44 is subjected to pressures in opposite directions from both sides, a portion of the toner in the developer conveyance path 44 flows back through the open part of the upper portion, thereby reducing the pressure applied to the toner in the developer conveyance path 44. This configuration can prevent the toner from being solidified in the developer conveyance path 44.
However, in such a comparative configuration, when the amount of developer in the developer chamber 8 decreases, the amount of toner supplied to the developing device 4 in any given replenishment becomes one third (⅓) or less of the predetermined amount of toner replenishment.
The amount of toner supplied to the developing device 4 decreases because, when the interior of the developer chamber 8 is sufficiently filled with toner, even if the internal pressure increases to some extent, the toner does not flow back through the open part of the upper portion due to the pressure corresponding to the height of the toner in the developer chamber 8 (hereinafter referred to as “developer pressure”). However, when the amount of toner in the developer chamber 8 decreases and the developer pressure is lowered, a large amount of toner in the developer conveyance path 44 flows back to the developer chamber 8 due to the internal pressure. As a result, the amount of toner that falls down through the toner replenishment port 44a decreases and the amount of toner supplied to the developing device 4 decreases.
The prototype of the toner cartridge 7 illustrated in
An experiment was performed with the prototype illustrated in
In addition, other experiments were performed with other toner cartridges 7 in which the communication port 45d is disposed directly above the toner replenishment port 44a as illustrated in
When the internal pressure increases, the internal pressure in the direction opposite to the direction of conveyance of toner by the conveying screw 43 is applied to the toner in the developer conveyance path 44. Therefore, the toner in the developer conveyance path is difficult to move toward the toner replenishment port 44a.
When the amount of toner in the developer chamber 8 is large, the developer pressure corresponding to the height of the toner is high. Accordingly, the conveying screw 43 can supplies the predetermined amount of toner to the toner supply port 44b even if the toner in the developer chamber 8 is difficult to move, causing the toner supplied from the toner supply port 44b to push out the toner in the developer conveyance path 44 against the internal pressure. As a result, the amount of toner that moves in the developer conveyance path 44 does not decrease.
However, when the amount of toner in the developer chamber 8 decreases and the developer pressure in front of the toner supply port 44b decreases, a portion of the toner transported to the toner supply port 44b by the conveying screw 43 does not enter the developer conveyance path 44 through the toner supply port 44b and flows back to the developer chamber 8. As a result, the amount of toner supplied through the toner supply port 44b decreases, and the effect is reduced that the toner supplied through the toner supply port 44b pushes out the toner in the developer conveyance path 44 toward the toner replenishment port 44a against the internal pressure. Therefore, the amount of toner that moves to the toner replenishment port 44a in the developer conveyance path 44 decreases. As a result, it is assumed that the amount of toner that falls down through the toner replenishment port 44a decreases within one replenishment duration, and the amount of toner replenishment decreases.
With the communication port 45d, when the internal pressure increases, toner flows back through the communication port 45d to the developer chamber 8, and a gap is formed in the toner between the communication port 45d and the toner replenishment port 44a The air in the developing device 4 is discharged from the communication port 45d through the gap. Accordingly, it is assumed that the pressure applied to the toner in the developer conveyance path 44 decreases, and the difficulty of toner movement is reduced. However, with the configurations illustrated in
In the case in which the communication port 45d is disposed on the downstream side from the toner replenishment port 44a in the developer conveyance direction as illustrated in
However, only the toner that has not fallen through the toner replenishment port 44a moves to the region downstream from the toner replenishment port 44a in the developer conveyance direction. Further, the pitch of the second blade 43a2 disposed in the region downstream from the toner replenishment port 44a in the developer conveyance direction is narrower than the pitch of the first blade 43a1, and the amount of toner movement per rotation of the conveying screw 43 is low. Further, the direction of conveyance of toner in the region downstream from the toner replenishment port 44a in the developer conveyance direction is opposite to the direction of conveyance of toner between the toner supply port 44b and the toner replenishment port 44a. As a result, the difficulty of toner movement from the toner supply port 44b to the toner replenishment port 44a is not reduced so much, and a portion of the toner transported to the toner supply port 44b by the conveying screw 43 does not enter the developer conveyance path 44 from the toner supply port 44b but flows back to the developer chamber 8 as indicated by arrow F in
In the case in which the communication port 45d is disposed directly above the toner replenishment port 44a as illustrated in
On the other hand, in the case according to the present embodiment in which the communication port 45d is disposed between the toner supply port 44b and the toner replenishment port 44a, the decrease in the amount of toner replenishment is reduced by about 20% when the amount of toner in the developer chamber 8 decreases. If the reduction is about 20%, a substantially predetermined amount of toner can be supplied even when the amount of toner in the developer chamber 8 is low.
In the present embodiment, when the amount of toner in the developer chamber 8 is low, the toner in the developer conveyance path 44 flows back to the developer chamber 8 through the communication port 45d due to the internal pressure, a gap through which air in the developing device 4 flows is formed in the toner between the toner replenishment port 44a and the communication port 45d. As a result, the air in the developing device 4 flows as indicated by arrow E1 in
Further, the downstream end of the communication port 45d is preferably located upstream from at least the upstream end of the toner replenishment port 44a in the developer conveyance direction. This is because, if the downstream end of the communication port 45d is located downstream from the upstream end of the toner replenishment port 44a in the developer conveyance direction and a part of the communication port 45d is located above the toner replenishment port 44a, the toner immediately before falling down through the toner replenishment port 44a may flow back through the communication port 45d to the developer chamber 8, causing the amount of toner replenishment to decrease. Accordingly, by positioning the downstream end of the communication port 45d upstream from at least the upstream end of the toner replenishment port 44a in the developer conveyance direction, the decrease in the amount of toner replenishment can be minimized.
Further, the upstream end of the communication port 45d is preferably located downstream from the toner supply port 44b in the developer conveyance direction and is preferably a hole surrounded by the closed rim 45d0 that is present in any direction perpendicular to the direction in which the developer conveyance path 44 communicates with the developer chamber 8 via the communication port 45d. This is because, if the upstream end of the communication port 45d is located at the position of the toner supply port 44b and the communication port 45d is connected to the toner supply port 44b, the amount of toner supplied to the developer conveyance path 44 is difficult to be controlled and the conveying screw 43 is not controlled to adjust the amount of toner replenishment satisfactorily.
In addition, if the communication port 45d is large, the amount of toner that flows back through the communication port 45d may increase and the amount of toner replenishment may decrease. Therefore, the communication port 45d is preferably not large so much.
Further, as illustrated in
Further, the length L1 of the toner replenishment port 44a in the developer conveyance direction is shorter (narrower) than the pitch P of the first blade 43a1 of the conveying screw 43. The toner cartridge 7 includes a shutter that opens and closes the toner replenishment port 44a. As the toner cartridge 7 is installed in the printer 100, the shutter opens. Since the length L1 of the toner replenishment port 44a in the developer conveyance direction is shorter (narrower) than the pitch P of the first blade 43a1 of the conveying screw 43, the amount of toner that falls down through the toner replenishment port 44a can be minimized when the shutter opens.
Further, although the toner cartridge 7 according to the present embodiment includes the developer chamber 8 and the developer collection chamber 9, the developer collection chamber 9 may be separated from the toner cartridge 7.
As described above, according to the present disclosure, the decrease in an amount of developer discharged through a discharge port to a developing device when the amount of developer in a developer chamber is low can be minimized. The embodiments described above are examples and can provide, for example, the following effects, respectively.
Aspect 1
A developer container such as the toner cartridge 7 includes a developer chamber such as the developer chamber 8 to store a developer, a discharge port such as the toner replenishment port 44a to discharge the developer in the developer chamber 8 to the developing device 4, a developer conveyance path such as the developer conveyance path 44 to transport the developer in the developer chamber 8 to the discharge port, a supply port such as the toner supply port 44b to supply the developer in the developer chamber 8 to the developer conveyance path 44, a conveyor such as the conveying screw 43 disposed in the developer conveyance path 44 to transport the developer to the discharge port, a partition such as the partition 45 partitioning between the developer conveyance path 44 and the developer chamber 8, and a communication port such as the communication port 45d disposed in the partition 45 and between the discharge port and the supply port and connecting the developer conveyance path 44 with the developer chamber 8.
As described above, with this configuration of the communication port between the discharge port and the supply port, the decrease in the amount of developer discharged through the discharge port to the developing device 4 when the amount of developer in the developer chamber 8 is low can be effectively minimized.
Aspect 2
In aspect 1, the communication port 45d is a hole surrounded by a closed rim 45d0 in a direction perpendicular to a direction in which the developer conveyance path 44 communicates with the developer chamber 8 via the communication port 45d.
This configuration can prevent the developer from entering the developer conveyance path 44 through the communication port 45d and the amount of developer flowing back through the communication port 45d from increasing.
Aspect 3
In aspect 1 or 2, a length of the communication port 45d in the developer conveyance direction is shorter than a length of the discharge port such as the toner replenishment port 44a in the developer conveyance direction.
As described above in the above embodiments, this configuration can prevent the developer from entering the developer conveyance path 44 through the communication port 45d and the amount of developer flowing back through the communication port 45d from increasing.
Aspect 4
In any one of aspects 1 to 3, the conveyor such as the conveying screw 43 includes a shaft 43b and a helical blade such as the first blade 43a1 to transport the developer supplied to the supply port such as the toner supply port 44b to the discharge port such as the toner replenishment port 44a. A length of the communication port 45d in the direction of conveyance of the developer is shorter than one pitch of the helical blade.
As described above in the above embodiments, this configuration can prevent the developer from entering the developer conveyance path 44 through the communication port 45d and the amount of developer flowing back through the communication port 45d from increasing.
Aspect 5
In aspect 4, the one pitch of the helical blade such as the first blade 43a1 is longer than the length of the discharge port such as the toner replenishment port 44a in the direction of conveyance of the developer, and the length of the discharge port in the direction of conveyance of the developer is longer than the length of the communication port 45d in the direction of conveyance of the developer.
As described above in the above embodiments, this configuration can minimize the amount of toner that falls down through the discharge port such as the toner replenishment port 44a when the shutter opens, and prevent the developer from entering the developer conveyance path 44 through the communication port 45d and the amount of developer flowing back through the communication port 45d from increasing.
Aspect 6
A developer supply device includes a developer container such as the toner cartridge 7 in any one of aspects 1 to 5 to replenish the developer to the developing device 4.
As described in the above embodiment, this configuration can minimize the decrease in the amount of developer supplied to the developing device 4 when the amount of developer in the developer container is low.
Aspect 7
A process cartridge such as the process cartridge 1 includes an image bearer such as the photoconductor 2 to bear a latent image, the developing device 4 to develop the latent image on the image bearer, and the developer container such as the toner cartridge 7 in any one of aspects 1 to 5 to store the developer such as toner to be supplied to the developing device 4. The process cartridge 1 is removably installable in an image forming apparatus such as the printer 100.
This configuration can minimize the decrease in the amount of developer supplied to the developing device 4 when the amount of developer in the developer container is low.
Aspect 8
An image forming apparatus such as the printer 100 includes an image bearer such as the photoconductor 2 to bear a latent image, the developing device 4 to develop the latent image on the image bearer, and the developer container such as the toner cartridge 7 in any one of aspects 1 to 5 to store the developer such as toner to be supplied to the developing device 4.
This configuration can minimize the decrease in the amount of developer supplied to the developing device 4 when the amount of developer in the developer container is low.
The above-described embodiments are illustrative and do not limit the present disclosure. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-220553 | Nov 2018 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20130028638 | Tsuritani et al. | Jan 2013 | A1 |
| 20130149011 | Hayashida | Jun 2013 | A1 |
| 20130259532 | Kubota | Oct 2013 | A1 |
| 20140050502 | Tsuritani | Feb 2014 | A1 |
| 20170168446 | Nieda | Jun 2017 | A1 |
| 20170199490 | Nieda | Jul 2017 | A1 |
| 20180112762 | Nieda | Apr 2018 | A1 |
| 20180267430 | Kita et al. | Sep 2018 | A1 |
| 20180356748 | Matsumoto et al. | Dec 2018 | A1 |
| 20190064699 | Nodera et al. | Feb 2019 | A1 |
| 20190179237 | Kita et al. | Jun 2019 | A1 |
| 20190243284 | Nieda | Aug 2019 | A1 |
| 20190243285 | Nieda | Aug 2019 | A1 |
| 20190243303 | Nieda | Aug 2019 | A1 |
| 20190286011 | Nieda et al. | Sep 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 2009042790 | Feb 2009 | JP |
| 2010-020227 | Jan 2010 | JP |
| 2013-029570 | Feb 2013 | JP |
| 2014-119704 | Jun 2014 | JP |
| Entry |
|---|
| U.S. Appl. No. 16/316,523, filed Jul. 13, 2017, Kuniyori Takano, et al. |
| Number | Date | Country | |
|---|---|---|---|
| 20200166872 A1 | May 2020 | US |
