Patent Grant
11256193
This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2020-004127 filed Jan. 15, 2020.
The present disclosure relates to a powder transport device, a developing device, and an image forming apparatus.
JP-A-2006-98883 describes a developing device for developing an electrostatic latent image formed on an image carrier with a developer. The developing device includes a housing, a transport member, and a developing roller. The housing can accommodate the developer. The transport member transports the developer. The transport member includes a shaft portion and a blade portion. The shaft portion is rotatably attached to the housing. The blade portion is integrally formed around the shaft portion in a spiral shape. The developing roller causes the developer transported by the transport member to adhere to the image carrier. The blade portion has plural notch portions such that a communication portion spirally extending from one end of the shaft portion to the other end of the shaft portion can be formed.
Aspects of non-limiting embodiments of the present disclosure relate to reducing the size per blade member as compared with a case where a single blade member is provided.
Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above.
According to an aspect of the present disclosure, there is provided A powder transport device including: a rotation shaft rotatable supported in a container chamber that contains powder; and plural blade members detachably attached to the rotation shaft, the blade members including spiral blades configured to transport the powder in an axial direction of the rotation shaft in response to the rotation shaft rotating.
Exemplary embodiment(s) of the present disclosure will be described in detail based on the following figures, wherein:
Next, an exemplary embodiment and an example will be described in more detail with reference to the accompanying drawings. It is noted that the present disclosure is not limited to the exemplary embodiment and the example.
It is also noted that in the following description made with reference to the accompanying drawings, the drawings are schematic and ratios of dimensions or the like of elements are different from actual ones. Illustration of elements and members other than those necessary for the description may be omitted as appropriate for the sake of easy understanding.
(1) Overall Configuration and Operation of Image Forming Apparatus
(1.1) Overall Configuration of Image Forming Apparatus
The image forming apparatus 1 includes an image forming device 10, a sheet feeding device 20, a reading device 30, an operation display 40, an image processor 50, and a system controller 60. The sheet feeding device 20 is attached to a lower portion of the image forming device 10. The reading device 30 is attached to an upper portion of the image forming device 10. When the image forming apparatus 1 performs a print function or a copy function, an image is formed on a recording medium such as a sheet.
The image forming device 10 includes exposure devices 12, photoconductor units 13, developing devices 14, a transfer device 15, a fixing device 16, and a toner supply device (not illustrated). The image forming device 10 forms a toner image on a sheet fed from the sheet feeding device 20 based on image information received from the image processor 50.
The sheet feeding device 20 including sheet trays 21, 22 is disposed at a bottom portion of the image forming device 10. A tray module TM is disposed below the sheet feeding device 20. The tray module TM includes multiple (two in this exemplary embodiment) sheet trays T1, T2 that are stacked in up and down directions. The sheet trays T1, T2 accommodate sheets. The tray module TM is connected to the image forming device 10 and feeds sheets to the image forming device 10.
The reading device 30 is disposed above the image forming device 10. The reading device 30 reads an image on a sheet by an image sensor (not illustrated) such as a charge coupled device (CCD) line sensor, and converts the image into image data that is electric signals.
The operation display 40 as a user interface is disposed on the front surface of the reading device 30. The operation display 40 includes a combination of a liquid crystal display panel, various operation buttons, and a touch panel. A user of the image forming apparatus 1 inputs various settings and instructions via the operation display 40. Various types of information is displayed on the liquid crystal display panel, for the user of the image forming apparatus 1.
The image processor 50 generates image data based on print information acquired from an external device (for example, a digital camera, a mobile terminal, a personal computer, or the like), and performs various types of image processing using the image data input by the reading device 30.
(1.2) Configuration and Operation of Image Forming Device 10
In the image forming apparatus 1 having the configuration described above, a sheet designated by a print job is sent from the sheet feeding device 20 to the image forming device 10 in accordance with timing of image formation.
The photoconductor units 13 are arranged side by side above the sheet feeding device 20. Each photoconductor unit 13 includes a photoconductor drum 31 that is driven to rotate. Toner images of yellow (Y), magenta (M), cyan (C), and black (K) are formed by the respective developing devices 14 on the respective photoconductor drums 31 on which electrostatic latent images have been formed by the exposure devices 12.
The toner images of the respective colors formed on the photoconductor drums 31 of the photoconductor units 13 are sequentially electrostatically transferred (primarily transferred) onto the intermediate transfer belt 51 of the transfer device 15, so that a superimposed toner image is formed in which the toner images of the respective colors are superimposed. The secondary transfer roller 52 collectively transfers the superimposed toner image on the intermediate transfer belt 51 onto the sheet that is sent by a pair of registration rollers 24 and guided by a transport guide.
In the fixing device 16, a fixing nip portion NP (fixing region) is formed by a pressure-contact region between a heating module 16A and a pressure module 16B.
The sheet on which the toner image is collectively transferred by the transfer device 15 is transported to the fixing nip portion NP of the fixing device 16 through the transport guide in a state in which the toner images are unfixed. The toner images are fixed by an action of heating and pressurizing by the heating module 16A and the pressure module 16B.
The sheet on which the fixed toner image is formed is guided by the transport guide, is discharged from a pair of discharge rollers 69 to a sheet discharge tray TR1 on an upper surface of the image forming apparatus 1, and is accommodated there.
When duplex printing is performed in an automatic manner, the sheet is reversed and sent to the image forming device 10 again. Then, after a toner image is transferred and fixed to the sheet, the sheet is discharged to the sheet discharge tray TR1.
(2) Functional Configuration and Operation of Image Forming Apparatus
(2.1) Developing Device
The developing device 14 includes a developing housing 41, a developing roller 42, an agitation auger 43A, and a supply auger 43B. The developing housing 41 contains a developer. The developing housing 41 is an example of a container chamber. The developing roller 42 faces the photoconductor drum 31. The agitation auger 43A transports the developer while agitating the developer. The agitation auger 43A is an example of a powder transport device, and the developer is an example of powder. The supply auger 43B supplies the developer to the developing roller 42. Hereinafter, the agitation auger 43A and the supply auger 43B may be referred to as “powder transport devices 43” without being distinguished from each other.
The developing roller 42 includes a cylindrical developing sleeve 42A and a magnet 42B. The developing sleeve 42A is supported so as to be rotatable with respect to the developing housing 41. The magnet 42B is a columnar magnet member. The magnet 42B is provided in the inner space of the developing sleeve 42A and fixed to the developing housing 41.
The developing sleeve 42A is configured as follows. That is, the developer is carried on the outer peripheral surface of the developing sleeve 42A by the magnetic force of the magnet 42B, and the developer is transported and supplied to the electrostatic latent image on the photoconductor drum 31 by the rotation of the developing sleeve 42A.
At a developing position, the electrostatic latent image formed on the surface of the photoconductor drum 31 is developed, and the developer after the development is returned to the developing housing 41 by the rotation of the developing roller 42.
In the developing housing 41, a partition wall 41a is erected between the agitation auger 43A and the supply auger 43B so as to partition the developing housing 41 into two developer containers 41A, 41B. Openings 45, 46 are formed in both end portions in a longitudinal direction of the partition wall 41a.
The agitation auger 434 and the supply auger 433 include spiral blades 43Ab, 43Bb around rotation shafts 43Aa, 43Ba. The agitation auger 43A and the supply auger 43B rotate along the inner walls of the developer containers 41A, 41B in response to receiving of a rotational force from a drive source (not illustrated), so as to transport the developer in predetermined directions in the developer containers 41A, 413.
Specifically, the agitation auger 43A transports the developer in the developer container 41A in an arrow (−Y) direction while agitating the developer. The supply auger 43B transports the developer in the developer container 413 in an arrow (Y) direction while agitating the developer. The developer transported in the arrow (−Y) direction moves to the developer container 41B through the opening 45. The developer transported in the arrow (Y) direction moves to the developer container 41A through the opening 46.
Accordingly, the developer in the developing housing 41 circulates while being agitated by the two augers, that is, the agitation auger 43A and the supply auger 433. Agitating the developer in this manner charges the toner in the developer.
A receiving port 47 is formed in an upper surface at one end portion of the developing housing 41 (in the Y direction, that is, on a rear side of the apparatus). The developing device 14 receives the toner supplied from the toner supply device (not illustrated) through the receiving port 47. The toner received by the developing device 14 through the receiving port 47 is transported by the agitation auger 43A to the developer container 41A of the developing housing 41 and mixed with the developer.
The toner replenished from the toner supply device through the receiving port 47 is transported from the rear side (an IN side, that is, in the Y direction, hereinafter which will be referred to as an “IN side”.) to the front side (an OUT side, that is, in the −Y direction, hereinafter which will be referred to as an “OUT side”) while being agitated by the agitation auger 43A and is moved to the supply auger 43B at the front side (that is, at the OUT side). Then, the toner supplied from the supply auger 43B is supplied to the developing roller 42.
An auto toner concentration (ATC) sensor SR is disposed in the developing device 14. The ATC sensor SR measures a ratio of the toner to the carrier of the developer circulating in the developing housing 41 (hereinafter, this ratio may be referred to as a “toner concentration” (TC)). The ATC sensor SR is an example of a detector. The ATC sensor SR measures a change in permeability corresponding to the toner concentration (TC) in the developer through a detection surface that is in contact with the developer. The ATC sensor SR detects the toner concentration (TC), for example, by detecting a changing analog output voltage.
In the image forming apparatus 1, a controller instructs toner supply from the toner supply device based on the measurement value obtained by the ATC sensor SR, so that the TC value of the developer is kept at a predetermined value.
In the present exemplary embodiment, the toner is supplied to the developing roller 42 from the OUT side to the IN side. The toner supply amount decreases by the time when the toner reaches the IN side. In order to control the toner supply amount appropriately, the ATC sensor SR is disposed on the OUT side of the agitation auger 43A.
A discharge port 48 is formed at a lower surface of an end portion (in the V direction, that is, at the IN side) of the developing housing 41. A reverse spiral blade 44c is disposed upstream of the discharge port 48 in the Y direction. A spiral direction of the reverse spiral blade 44c is opposite to that of the spiral blade 43Bb at the other portions. Thus, most of the developer transported in the arrow (Y) direction in the developer container 41B of the developing housing 41 is guided to the opening 46 by the reverse spiral blade 44c and moved to the developer container 41A, while a part of the developer goes beyond the reverse spiral blade 44c and is discharged to the outside of the developing device 14 through the discharge port 48.
(2.2) Configuration of Powder Transport Device
As illustrated in
A protrusion 432Ab is formed at one end portion of the cylindrical portion 432A of the blade member 432. A recess 432Ac is formed at the other end portion of the cylindrical portion 432A of the blade member 432. The protrusions 432Ab and the recesses 432Ac of each blade member 432 are fitted to the protrusions of 432Ab and the recesses 432Ac of adjacent blade members 432, so that each blade members 432 is positioned with respect to the rotation shaft 431 in the rotation direction, and the spiral blades 432B formed in the blade members 432 are continuous in the axial direction of the rotation shaft 431.
In a state where the blade members 432 are positioned with respect to the rotation shaft 431 in the rotation direction by fitting the protrusions 432Ab and the recesses 432Ac to each other, the blade members 432 are fixed with fixing tools 431A. The fixing tool 431A is an example of a fixing member. In the present exemplary embodiment, the fixing tool 431A is a slotted set screw or a parallel pin. As illustrated in
In this way, in the powder transport device 43, the plural blade members 432 each including the spiral blade 432B which transports the powder along the axial direction of the rotation shaft 431 are attached such that the spiral blades 432B are continuous to each other in the axial direction of the rotation shaft 431. Accordingly, the size per blade member can be reduced as compared with a case where a single blade member is provided.
As illustrated in
As illustrated in
With this configuration, a spiral blade 432BA that is the spiral blade 432B of the single blade member 432 before its phase is shifted in the transport direction f the developer and a spiral blade 432BB that is the spiral blade 432B of the single blade member 432 after its phase is shifted in the transport direction of the developer are continuous without a gap. Thus, it is possible to prevent the transportability of the powder from changing at the portion of the shape 432Bb which shifts the phase of the spiral blade 432B.
In the developing device 14, when the powder transport device 43 rotates, the spiral blade 432B periodically approaches a detection surface SRa of the ATC sensor SR, so that the output of the ATC sensor SR changes periodically. In addition to the spiral blade 432B, a paddle 432D is provided that extends from the blade member 432 toward the outer circumference. The paddle 432D presses the developer against the detection surface SRa to reduce the influence on the change in the developer amount in the developing device 14.
As illustrated in
(2.3) Operation of Powder Transport Device
The operation of the powder transport device 43 to transport the developer will be described below with reference to the drawings.
When the powder transport device 430 of the comparative example is driven to rotate, as illustrated in
When the developer is transported in a state in which the phase of the adjacent spiral blade 432B is shifted and the step G is generated at the joint between the spiral blades 432B as illustrated in
When the powder transport device 43 is driven to rotate, the blade members 432 may be deviated by the distance corresponding to the clearance generated by the fitting between the protrusion 432Ab and the recess 432Ac (see
The shape 432Bb is provided such that the phase of the spiral blade 432B of the blade member 432 upstream of the joint (indicated by the arrow A in
It is noted that it is not necessary to provide the shift shape 432Bb in the blade member 432, if the phase of the spiral blade 432B of the downstream blade member 432 in the transport direction of the developer among the adjacent blade members 432 is shifted at the joint between the spiral blades 432B to advance in the transport direction and is fixed. For example, the length of the spiral blade 432B may be designed such that a phase at one end portion of the spiral blade 432B provided in a single blade member 432 is different from a phase at the other end portion of the spiral blade 432B provided in the single blade member 432, and the blade member 432 may be manufactured based on this design.
In the present exemplary embodiment, the agitation auger 43A and the supply auger 43B used to transport the developer in the developing device 14 of the image forming apparatus 1 have been described as specific examples of the powder transport device 43. The powder transported by the powder transport device 43 may be inorganic material powders or organic material powders for use in various technical fields such as an electronic field, an energy field, a medical field, and a food field, for example, powders of fine ceramics, metal materials, polymer materials, battery materials, electronic materials, composite materials, pharmaceutical materials, or food materials.
The foregoing description of the exemplary embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2020-004127 | Jan 2020 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3705644 | Kawchitch | Dec 1972 | A |
| 4187030 | Godley | Feb 1980 | A |
| 5541710 | Stewart | Jul 1996 | A |
| 20150268585 | Kadowaki | Sep 2015 | A1 |
| 20170115597 | Kawashima | Apr 2017 | A1 |
| 20180059606 | Mugita | Mar 2018 | A1 |
| Number | Date | Country |
|---|---|---|
| 2006-098883 | Apr 2006 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20210216028 A1 | Jul 2021 | US |
