Patent Application
20110280631
The present invention relates to a developer storage body, an image forming unit and an image forming apparatus.
Generally, an image forming apparatus using electrophotography, such as a printer, a facsimile machine or a copier, includes an image forming unit, an LED head, a transfer roller, a fixing unit and the like. The image forming unit includes a photosensitive drum, a charging roller, a developing unit, a cleaning roller and the like. The charging roller uniformly charges a surface of the photosensitive drum, and the LED head emits light to expose the surface of the photosensitive drum according to image data so as to form a latent image. The developing unit develops the latent image to form a toner image. The transfer roller transfers the toner image to a sheet as a printing medium. The fixing unit fixes the toner image to the sheet.
The image forming unit includes an image forming unit main body and a toner cartridge (i.e., a developer storage body) detachably mounted to the image forming unit main body. The toner cartridge includes an outer case in which a toner as a developer is stored, and an inner case rotatably provided in the outer case. The outer case has a toner supply opening through which the toner is supplied to the image forming unit main body. The inner case has a shutter part for opening and closing the toner supply opening (see, for example, Japanese Laid-Open Patent Publication No. 2001-42620).
Recently, there is a demand for a developer storage body capable of sufficiently supplying a developer to an image forming unit main body.
In an aspect of the present invention, it is intended to provide a developer storage body capable of sufficiently supplying a developer to an image forming unit main body, and to provide an image forming unit and an image forming apparatus using such a developer storage body.
According to an aspect of the present invention, there is provided a developer storage body including an outer case enclosing a space in which a developer is stored and having a first opening, and an inner case rotatably provided in the outer case and having a second opening. The inner case is rotatable with respect to the outer case between an opening position in which the inner case opens the first opening and a closing position in which the inner case closes the first opening. The developer storage body further includes an operating portion provided for operation to rotate the inner case with respect to the outer case between the opening position and the closing position. The inner case includes a bottom wall having the second opening, and a plurality of beams provided so as to extend between edges of the bottom wall. The beam has an inclined upper surface. The inclined upper surface is inclined downward in a gravity direction toward a side end of the beam in a cross-section of the beam.
With such a configuration, the developer is not likely to be accumulated on the inclined upper surface of each beam, and therefore a sufficient amount of developer can be supplied to the outside of the developer storage body.
According to still another aspect of the present invention, there is provided an image forming unit to which the above described developer storage body is mounted.
According to yet another aspect of the present invention, there is provided an image forming apparatus to which the above described image forming unit is mounted.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific embodiments, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
In the attached drawings:
Hereinafter, embodiments of the present invention will be described with reference to drawings.
An LED head 27 as an exposure device is provided above and facing the photosensitive drum 21 of the image forming unit 20. The LED head 27 is configured to emit light to expose a surface of the photosensitive drum 21 to form a latent image. A transfer roller 14 as a transfer member is provided below and facing the photosensitive drum 21 of the image forming unit 20. The transfer roller 14 is configured to transfer a toner image (i.e., a developer image) from the photosensitive drum 21 to the sheet 11. A fixing unit 15 as a fixing device is provided on a downstream side (i.e., the left in
Next, an operation of the printer 10 will be described.
When the hopping roller 12 is rotated, the individual sheet 11 is fed out of the sheet cassette 17. The sheet 11 is further fed by the registration rollers 13a and 13b to the image forming unit 20 and the transfer roller 14 at a timing adjusted in accordance with formation of the toner image on the photosensitive drum 21. The toner image is transferred from the photosensitive drum 21 to the sheet 11 by the transfer roller 14. Then, the sheet 11 is feed to the fixing unit 15, and is heated and pressed by the pressing roller 15a and the heating roller 15b, so that the toner image is fixed to the sheet 11. The sheet 11 (to which the toner image is fixed) is ejected by the ejection rollers 16a through 16d to the outside of the housing 18.
Next, a configuration of the image forming unit 20 will be described.
As shown in
The toner cartridge 31 has a toner storage chamber 32 as a developer storage chamber for storing the toner. A toner supply opening 39 as a first opening is formed on the toner cartridge 31, through which the toner is supplied to the outside of the toner cartridge 31. The image forming unit main body 19 has a toner receiving opening 48 as a developer receiving opening provided so as to face the toner supply opening 39, and a toner chamber 33 as a developer chamber to which the toner is supplied from the toner cartridge 31 via the toner supply opening 39 and the toner receiving opening 48.
Next, an operation of the image forming unit 20 will be described.
When the toner is supplied from the toner cartridge 31 to the toner chamber 33 of the image forming unit main body 19, the toner is supplied to the developing roller 23 by the toner supply roller 24, and a toner layer is formed on the surface of the developing roller 23. The toner layer has a uniform thickness regulated by the developing blade 25.
The surface of the photosensitive drum 21 is uniformly charged by the charging roller 22, and is exposed with light emitted by the LED head 27, so that a latent image is formed on the surface of the photosensitive drum 21. The latent image is developed by the toner supplied by the developing roller 23, so that a toner image is formed on the surface of the photosensitive drum 21. The toner image is transferred from the photosensitive drum 21 to the sheet 11 by the transfer roller 14. The residual toner that remains after transferring of the toner image is scraped off by the cleaning roller 26, and is removed therefrom.
Next, a configuration of the toner cartridge 31 will be described.
As shown in
The outer case 34 has a bottom wall W1 having a semicircular cross-sectional shape. The outer case 34 further has side walls W2 and W3 extending upward from the bottom wall W1, and front and rear end walls W4 and W5 (
The protrusion 36 protrudes downward from an inner surface of the top wall W6 toward the rotation axis (i.e., a center axis) of the inner case 35. The protrusion 36 extends parallel to an axial direction of the inner case (i.e., longitudinal direction of the outer case 34), and reaches the same position as the inner case 35 in the axial direction. Further, the protrusion 36 is disposed in opposition to the toner supply opening 39 with respect to the center axis of the inner case 35. To be more specific, a center of the toner supply opening 39 in a widthwise direction and a tip of the protrusion 36 are apart from each other by 180 degrees with respect to the center axis of the inner case 35. Inner edges eg21 surrounding the toner supply opening 39 are inclined (tapered) so that an opening area of the toner supply opening 39 increases from an inner circumferential surface of the bottom wall W1 toward an outer circumferential surface of the bottom wall W1.
In this embodiment, the toner supply opening 39 is located at a position shifted from a lowermost position of the bottom wall W1 so as to correspond to a position to which the toner falls in the toner chamber 33 (
The inner case 35 includes an arcuate cylindrical portion 72 as a bottom wall having an arcuate cross-section. The arcuate cylindrical portion 72 extends in a circumferential direction at a predetermined angle, for example, substantially 180 degrees, and acts as a shutter. The inner case 35 further includes a truss construction 50 as a beam construction provided so as to bridge between two edges eg11 and eg 12 of the arcuate cylindrical portion 72 in a circumferential direction. The inner case 35 further includes a cylindrical part 73 provided at an end of the arcuate cylindrical portion 72 and the truss construction 50 in the axial (longitudinal) direction.
The knob portion 74 (the operating portion) includes a knob supporting portion 75 of a cylindrical shape formed integrally with and adjacent to the cylindrical part 73 of the inner case 35. The knob portion 74 further includes a knob 76 protruding outward (in a radial direction) from the knob supporting portion 75 at a predetermined position in the circumferential direction of the knob supporting portion 75.
The inner case 35 has a supply opening 77 as a second opening (i.e., an opening of the inner case 35) formed on the arcuate cylindrical portion 72. The supply opening 77 is located at a predetermined position in the circumferential direction of the arcuate cylindrical portion 72. Further, the supply opening 77 is in the form of an elongated hole, and extends a predetermined length in the axial direction of the arcuate cylindrical portion so as to correspond to the toner supply opening 39. The inner case 35 further has a closing portion 78 formed on the arcuate cylindrical portion 72 and adjacent to the supply opening 77 in the circumferential direction. Inner edges eg31 surrounding the supply opening 77 are inclined so that an opening area of the supply opening 77 increases from an inner circumferential surface of the arcuate cylindrical portion 72 toward an outer circumferential surface of the arcuate cylindrical portion 72. Seal members 91 and 92 are bonded to predetermined positions on an outer circumferential surface of the closing portion 78. The seal members 91 and 92 are formed of sheet-like bodies.
When an operator holds the knob 76 and rotates the inner case 35 in directions shown by arrows A and B (
In a state where the inner case 35 is in the closing position, the tip of the protrusion 36 is in a position opposite to the closing portion 78, and presses the inner case 35 toward the toner supply opening 39. Therefore, in the state where the inner case 35 is in the closing position, the seal members 91 and 92 are located on both sides of the toner supply opening 39 in the circumferential direction, and are pressed against the inner circumferential surface of the outer case 34. With such a configuration, leakage of the toner through between the outer case 34 and the inner case 35 is prevented.
Next, the truss construction 50 will be described.
In
The beam 51 and the beam 52 are connected by the two beams 55 and the beam 60. The beam 52 and the beam 53 are connected by the two beams 56 and the beam 60. The beam 53 and the beam 54 are connected by the two beams 57 and the beam 60. The beam 54 and the cylindrical part 73 are connected by the two beams 58, the two beams 59 and the beam 60.
To be more specific, the two beams 55 extend between the beam 51 and the adjacent beam 52 so that the two beams 55 intersect each other. The two beams 56 extend between the beam 52 and the adjacent beam 53 so that the two beams 56 intersect each other. The two beams 57 extend between the beam 53 and the adjacent beam 54 so that the two beams 57 intersect each other. The two beams 58 and the two beams 59 extend between the beam 54 and the adjacent cylindrical part 73 so that the two beams 58 and the two beams 59 intersect each other. With such a configuration, the truss construction 50 has a high strength.
As described above, when the inner case 35 is in the closing position, the protrusion 36 of the outer case 34 (in the position opposite to the closing portion 78) presses the inner case 35 toward the toner supply opening 39. In this state, since the beams 51 through 54 extend perpendicular to an extending direction of the protrusion 36 (i.e., the longitudinal direction of the outer case 34), the beams 55 through 59 extend so as to be inclined with respect to the extending direction of the protrusion 36, and the beam 60 extends parallel to the extending direction of the protrusion 36, the truss construction 50 is not twisted, deformed or broken. Since the strength of the truss construction 50 is ensured, the inner case 35 can press the seal members 91 and 92 against the inner surface of the outer case 34 with a sufficient force. Thus, even when the toner cartridge 31 is dropped onto the ground in a state where the toner supply opening 39 is closed, or even when the toner cartridge 31 is applied with vibration, it is ensured that the toner is prevented from leaking outside through between the outer case 34 and the inner case 35.
In this regard, the beams 51 through 60 are formed to have sufficient widths so that the truss construction 50 is not deformed or broken.
Further, the truss construction 50 has portions at each of which two beams intersect each other. For example, the beams 51, 55 and 60 intersect each other at a portion q1. The beams 52, 55 and 56 intersect each other at portions q2 and q3. The beam 52 and the beam 60 intersect each other at a portion q4. The beams 53, 56, 57 and 60 intersect each other at a portion q5. The beams 54, 57 and 58 intersect each other at portions q6 and q7. The beam 54 and the beam 60 intersect each other at a portion q8. The beams 58, 59 and 60 intersect each other at a portion q9. The portions q1 through q9 have relatively large areas.
In this regard, if the toner is accumulated on the beams 51 through 60 and the portions q1 through q9, such accumulated toner is not supplied to the image forming unit main body 19.
Therefore, in the first embodiment, each of the beams 51 through 54 has a substantially triangular cross-sectional shape pointing upward (i.e., outward in a radial direction of the inner case 35). As a representative example,
Further, each of the beams 55 through 60 has a substantially semicircular cross-sectional shape which is convex upward. As a representative example,
As schematically shown in
The advantages of the first embodiment will be described in comparison with Comparison Example.
In Comparison Example, the toner may be accumulated on flat upper surfaces of the band-shaped portions 80b. Such a toner remains within the toner cartridge, and is not supplied to the image forming unit main body.
In contrast, according to the first embodiment, as shown in
Various modifications can be made to the first embodiment.
For example, the cross-sectional shapes of the beams 51 through 60 are not limited to those shown in
Further,
The inner case 135 shown in
With such a configuration, the toner is prevented from being accumulated on the beams 15, and a sufficient amount of toner can be supplied from the toner cartridge to the image forming unit main body.
The cross-sectional shape of the beam 151 is not limited to the trapezoidal shape. For example, the beam 151 can have a substantially triangular cross-sectional shape as shown in
In the above described first embodiment, the toner may be accumulated on the edges eg11 and eg12 of the arcuate cylindrical portion 72 since the edges eg11 and eg12 become parallel to a horizontal plane when the inner case 35 is in the opening position as shown in
Components of the second embodiment that are the same as those of the first embodiment are assigned the same reference numerals. With regard to the advantages obtained by the components which are the same as those of the first embodiment, explanations of the first embodiment are herein incorporated.
In the second embodiment, the edges eg41 and eg42 are inclined with respect to a gravity direction (i.e., vertical direction) at a predetermined angle, for example, 45 degrees or more, in a state where the inner case 235 is in the opening position as shown in
Therefore, the toner is prevented from being accumulated on the edges eg41 and eg42 of the arcuate cylindrical portion 72. Thus, a sufficient amount of toner can be supplied from the toner cartridge 31 to the image forming unit main body 19.
In this regard, the modification of the first embodiment (
In the above embodiments, descriptions have been made to the printer 10 as an example of the image forming apparatus. However, the present invention is applicable to a facsimile machine, a copier, a multifunction peripheral or the like. Further, although descriptions have been made to the monochrome printer, the present invention is applicable to a color image forming apparatus.
While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and improvements may be made to the invention without departing from the spirit and scope of the invention as described in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-112874 | May 2010 | JP | national |
