Patent Application
20110255906
The present invention relates to an image forming apparatus using electrophotography such as a printer, a facsimile machine or a combined machine. Further, the present invention relates to a developer storage body for storing a developer, and a developing device having the developer storage body.
An image forming apparatus using electrophotography is configured to form an image by uniformly charging a surface of a photosensitive body, exposing the surface of the photosensitive body to form a latent image, developing the latent image using a developing device to form a developer image (i.e., a toner image), and to transfer the developer image from the photosensitive body to a printing medium. Generally, the developing device has a detachable developer storage body for supplying the developer to the developing device.
In this regard, the developer may adhere to an inner surface of the developer storage body and an opening-and-closing member provided therein. In such cases, the developer storage body cannot supply a sufficient amount of the developer to the developing device.
Therefore, Patent Document 1 discloses a developer storage body having a mechanism that scrapes off the developer from the inner surface of the developer storage body and the like.
However, there are still cases where the developer remains in the developer storage body. In such cases, the developer stored in the developer storage body is not sufficiently supplied to the developing device, and is therefore not effectively used.
In an aspect of the present invention, it is intended to reduce an amount of a developer left in a developer storage body and to achieve effective use of the developer.
According to an aspect of the present invention, there is provided a developer storage portion storing a developer and having an elongated shape, an outlet opening provided at a substantially center portion of the developer storage portion in a longitudinal direction of the developer storage portion, inclined portions provided on both end portions of the developer storage portion in the longitudinal direction, a rotation member rotatably provided in the developer storage portion, and a film member provided on the rotation member. The film member is brought into contact with the inclined portions when the rotation member rotates.
With such a configuration, an amount of the developer left in the developer storage body can be reduced, and the developer can be effectively used.
According to another aspect of the present invention, there is provided a developing device including the above described developer storage body.
According to still another aspect of the present invention, there is provided an image forming apparatus including the above described developing device.
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.
The image forming apparatus 1 includes an image forming unit (also referred to as a process cartridge) 2 that forms an image on a printing medium P using a toner as a developer, and a housing 1A in which the image forming unit 2 is detachably mounted. A medium feeding path is formed in the housing 1A through which the printing medium P is fed. The medium feeding path is substantially S-shaped, and extends through the image forming unit 2.
Although the image forming apparatus 1 is described herein as being configured to include a single image forming unit 2 and to form a monochrome image (for example, black image) for convenience of explanation, it is also possible to configure the image forming apparatus 1 to include a plurality of image forming units 2 so as to form a color image.
A cassette 6 (i.e., a printing media storage portion) is detachably mounted to a lower part of image forming apparatus 1. The cassette 6 stores a stack of the printing media P such as printing sheets. A hopping roller 7 (i.e., a medium feeding mechanism) is provided above the cassette 6 for feeding the printing. medium P one by one out of the cassette 6. A pair of registration rollers 8 and 9 (i.e., a conveying mechanism) are provided in the vicinity of the hopping roller 7. The registration rollers 8 and 9 convey the printing medium P (fed out of the cassette 6 by the hopping roller 7) toward the image forming unit 2.
A transfer member 10 (for example, a transfer roller) is provided so as to face a photosensitive drum 25 (described later) of the image forming unit 2 via the medium feeding path. The transfer member 10 is applied with a transfer voltage by a high voltage power source, and transfers a toner image (i.e., a developer image) formed by the image forming unit 2 to the printing medium P.
A fixing unit is provided on a downstream side (i.e., left in
A pair of ejection rollers 13 and 14 and another pair of ejection rollers 15 and 16 are provided on a downstream side of the fixing unit (11, 12) along the medium feeding path. The ejection rollers 13, 14, 15 and 16 convey the printing medium P (to which the toner image is fixed) and eject the printing medium P outside the housing 1A. A stacker portion 1B is formed on an upper part of the housing 1A for placing the printing medium P thereon.
The image forming apparatus 1 further includes a control circuit board 18 (i.e., a control unit) on which a CPU or the like is mounted for controlling an image forming operation of the image forming apparatus 1.
The image forming unit 2 includes a charging member (i.e., a charging roller) 24 that uniformly charges the surface of the photosensitive drum 25, a developing member (i.e., a developing roller) 22 that develops a latent image formed on the surface of the photosensitive drum 25, and a supplying member (i.e., a supplying roller) 21 that supplies the toner to the surface of the developing member 22. The image forming unit 2 further includes a blade 23 that regulates a thickness of a toner layer formed on the surface of the developing member 22, and a cleaning member that removes the residual toner remaining on the photosensitive drum 25.
The charging member 24 includes, for example, a metal shaft and a conductive resilient layer formed on a circumferential surface of the metal shaft. The charging member 24 rotates contacting the photosensitive drum 25. The developing member 22 includes, for example, a metal shaft and a conductive resilient layer formed on a circumferential surface of the metal shaft. A coating can be applied to a surface of the conductive resilient layer as necessary. The developing member 22 rotates contacting the surface of the photosensitive drum 25. The blade 23 is constituted by, for example, a metal plate member which is bent. A bent portion of the blade 23 is pressed against the surface of the developing member 22 with a uniform pressing force. The cleaning member 26 includes, for example, a rubber roller or blade, and is provided so as to contact the surface of the photosensitive drum 25. The charging member 24, the developing member 22 and the supplying member 21 are respectively applied with a charging voltage, a developing voltage and a supplying voltage by not shown high voltage power sources.
The developing member 22, the supplying member 21 and the blade 23 constitute a developing device 20 that develops the latent image on the surface of the photosensitive drum 25. The developing device 20 has a toner holding space 27 as a developer holding space in which the developing member 22, the supplying member 21 and the blade 23 are provided.
The developing device 20 further includes a toner cartridge 5 as a developer storage body. The toner cartridge 5 is detachably mounted to a part above the toner holding space 27. An inner space of the toner cartridge 5 is referred to as a toner storage portion 19 as a developer storage portion. The toner is stored in the toner storage portion 19, and is supplied to the toner holding space 27 of the developing device 20 when a toner supply opening 35 (described later) is opened.
The exposure device 17 is provided above the photosensitive drum 25 of the image forming unit 2. The exposure device 17 emits light to expose the surface of the photosensitive drum 25 so as to form a latent image. The exposure device 17 includes, for example, an LED (Light Emitting Diode) head, and is fixed to an upper cover of the image forming apparatus 1.
Next, a basic operation of the image forming apparatus 1 will be described. In
In
The printing medium P to which the toner image is transferred is conveyed to the fixing unit (11, 12). The printing medium P is heated and pressed by the heat roller 11 and the backup roller 12, and the toner image is fixed to the printing medium P. The printing medium P to which the toner image is fixed is ejected out of the housing 1A by the ejection rollers 13, 14, 15 and 16. The ejected printing medium P is placed on the stacker portion 1B. The above described operation is controlled by the control circuit board 18.
The outer case 3 is in the form of a container, and has a substantially cylindrical shape extending parallel to an axial direction of the photosensitive drum 25 (
The inner case 4 has a substantially cylindrical shape, and is provided inside the outer case 3 so that the inner case 4 is rotatable contacting an inner circumferential surface of the outer case 3. The inner case 4 includes a cylindrical wall 43 having a substantially cylindrical shape. The inner case 4 further includes a closed end (referred to as a side wall 41) provided at an end of the cylindrical wall 43 in the longitudinal direction. The other end of the cylindrical wall 43 is opened. An upper part of the cylindrical wall 43 is formed into a framework structure. The inner case 4 has an opening 45 (
The closed end (i.e., the side wall 41 portion) of the inner case 4 protrudes outward from the opened end of the outer case 3. A lever 44 (as an operating portion) is formed integrally with the protruding portion of the inner case 4. The lever 44 is gripped by a user for operation to rotate the inner case 4. The side wall 31 of the outer case 3 and the side wall 41 of the inner case 4 constitute both ends (i.e., inner end surfaces) of the toner cartridge 5 in the longitudinal direction. Hereinafter, the side walls 31 and 41 are also referred to as “both side walls 31 and 41 of the outer cartridge 5” as necessary.
Further, when the user rotates the lever 44 in a direction shown by an arrow B (
The toner cartridge 5 has a rotation member 50 inside the inner case 4 as shown in
A film member 51 is fixed to the rotation member 50. The film member 51 is formed of material having suitable toughness and flexibility such as a polyester film. The film member 51 extends substantially entire length of the rotation member 50. In other words, the film member 51 extends from the vicinity of the side wall 31 to the vicinity of the side wall 41. A tip edge 510 (i.e., a longer edge) of the film member 51 contacts an inner circumferential surface of the cylindrical wall 43 of the inner case 4. When the rotation member 50 rotates, the film member 51 fixed to the rotation member 50 rotates contacting the inner circumferential surface of the inner case 4. The film member 51 is fixed to the rotation member 50 in such a shape that both end portions of the film member 51 in the longitudinal direction are located ahead (in the rotating direction of the film member 51) of a center portion of the film member 51 in the longitudinal direction, as will be described later.
As shown in
Further, as shown in
The film member 51 has a plurality of engaging holes 51a arranged in the longitudinal direction of the film member 51. The engaging holes 51a of the film member 51 engage engaging pins 50a formed on the rotation member 50, so that the film member 51 is fixed to the rotation member 50.
The film member 51 also has a plurality of (for example, seven) slits 52 arranged in the longitudinal direction of the film member 51. Each of the slits 52 extends in a direction substantially perpendicular to the longitudinal direction of the film member 51 from the tip edge 510 and has a predetermined length.
The film member 51 is fixed to the rotation member in such a shape that both end portions of the film member 51 in the longitudinal direction are located ahead, in the rotating direction of the film member 51, of a center portion of the film member 51 in the longitudinal direction. To be more specific, the film member 51 is so shaped that a portion closer to either end of the film member 51 is located ahead, in the rotating direction of the film member 51, of a portion closer to the center of the film member 51. In this example, the film member 51 is divided into three parts (i.e., two side parts and a center part) in the longitudinal direction. The side parts of the film member 51 are inclined with respect to the center part, i.e., with respect to the longitudinal direction of the film member 51. Alternatively, it is also possible that the film member 51 is entirely curved.
Examples of dimensions of the toner cartridge 5 will be described with reference to
A distance R1 (
As shown in
An angle (obtuse angle) A1 between the inclined portion 32 and the side wall 31 (i.e., the inner side surface of the toner cartridge 5) is, for example, 165.2°. Further, an angle (obtuse angle) A2 between the inclined portion 32 and the cylindrical wall 33 (i.e., the inner circumferential surface of the toner cartridge 5) is, for example, 104.78°. Similarly, an angle B1 between the inclined portion 42 and the side wall 41 is, for example, 165.2°. Further, an angle B2 between the inclined portion 42 and the cylindrical wall 43 is, for example, 104.78°. The angles A1, A2, B1 and B2 are not limited to these values. However, it is preferable that the angle A1 is greater than the angle A2 (i.e., A1>A2), and the angle B1 is greater than the angle B2 (i.e., B1>B2) so that the toner can easily slides downward along the inclined portions 32 and 42.
The inclined portions 32 and 42 respectively have lower ends 32a and 42a connected to the inner cylindrical surface of the toner cartridge 5 (defined by the cylindrical wall of the inner case 4). A distance L5 between the lower ends 32a and 42a of the inclined portions 32 and 42 is shorter than a length L6 of the film member 51 (L5<L6). The distance L5 is also referred to as a length of a bottom portion of the toner cartridge 5 except the inclined portions 32 and 42. Further, a length L7 of the toner supply opening 35 and a length L8 of the opening 45 are shorter than the distance L5 between lower ends 32a and 42a of the inclined portions 32 and 42 (i.e., L7<L5, L8<L5).
The film member 51 (made of a polyester film in this example) has a thickness of, for example, 0.125 mm. The length L6 of the film member 51 in the longitudinal direction of the toner cartridge 5 is, for example, 241.92 mm. Although the side parts of the film member 51 are inclined with respect to the center part of the film member 51 as described above, the film member 51 has an entire length of, for example, 245.44 mm when the film member 51 is straightly stretched.
Next, a function of the toner cartridge 5 of the first embodiment will be described.
When mounting the toner cartridge 5 to the image forming unit 2, a user places the toner cartridge 5 on the image forming unit 2, and rotates the lever 44 in the direction shown by the arrow A (
When the image forming apparatus 10 starts an image forming operation, a rotation of the driving source is transmitted to the gear 55, and the rotation member 50 rotates. With the rotation of the rotation member 50, the film member 51 rotates contacting the inner circumferential surface of the inner case 4 (i.e., the inner circumferential surface of the cylindrical wall 43), and scrapes off the toner from the inner circumferential surface of the inner case 4. Since the film member 51 has the above described shape (
In this regard, in a configuration in which the film member 51 does not contact the side walls 31 and 41 of the toner cartridge 5, the toner tends to remain at both ends of the toner cartridge 5 in the longitudinal direction, i.e., near the side walls 31 and 41. However, according to the first embodiment, the inclined portions 32 and 42 are provided at both ends of the toner cartridge 5, and therefore the toner (at both ends of the toner cartridge 5) slides down along the inclined portions 32 and 42 downward, and is scraped off by the film member 51.
Although
When detaching the toner cartridge 5 from the image forming unit 2, the user rotates the lever 44 in the direction indicated by the arrow B in
In the above described configuration, gaps are provided between the film member 51 and both side walls 31 and 41 of the toner cartridge 5. However, it is also possible that the film member 51 contacts both of or either one of the side walls 31 and 41 of the toner cartridge 5. In such a case, the toner adhering to the side walls 31 and 41 can be directly scraped off by the film member 51, as well as the toner adhering to the inclined portion 32 and 42. In contrast, when the gaps are provided between the film member 51 and both side walls 31 and 41 of the toner cartridge 5 as shown in
As described above, according to the first embodiment of the present invention, the toner cartridge 5 has the inclined portions 32 and 42 at both ends in the longitudinal direction. Further, the film member 51 is configured to contact the inclined portions 32 and 42, and to lead the toner adhering to the inclined portions 32 and 42 to the center portion of the toner cartridge 5. Therefore, it becomes possible to prevent the toner from remaining at both ends of the toner cartridge 5 in the longitudinal direction, and to supply sufficient amount of toner to the image forming unit 2.
Particularly, the obtuse angle A1 between the inclined portion 32 and the side wall 31 is greater than the obtuse angle A2 between the inclined portion 32 and the cylindrical wall 33, and the obtuse angle B1 between the inclined portion 42 and the side wall 41 is greater than the obtuse angle B2 between the inclined portion 42 and the cylindrical wall 43, with the result that the toner easily slides down along the inclined portions 32 and 42. Therefore, it becomes possible to effectively prevent the toner from remaining at both ends of the toner cartridge 5.
Further, the film member 51 is so shaped that both end portions of the film member 51 in the longitudinal direction are located ahead, in the rotating direction of the film member 51, of the center portion of the film member 51 in the longitudinal direction, and therefore the toner scraped off from the inclined portion 32 and 42 can effectively be led to the center portion of the toner cartridge 5 in the longitudinal direction.
Furthermore, the film member 51 has a plurality of slits 52, and therefore the film member 51 can be deformed according to shapes of the inclined portions 32 and 42. Thus, the film member 51 can smoothly scrapes off the toner from the inclined portions 32 and 42.
Moreover, the distance L5 between the lower ends 32a and 42a of the inclined portions 32 and 42 is shorter than the length of the film member 51, and therefore the film member 51 contacts at least part of the inclined portions 32 and 42. Thus, it is ensured that the film member 51 scrapes off the toner from the inclined portions 32 and 42.
In the above described toner cartridge 5, the outer case 3 has the inclined portion 32 and the inner case 4 has the inclined portion 42. However, the first embodiment is not limited to such a configuration. It is only necessary that the toner cartridge 5 has inclined portions at both ends in the longitudinal direction.
Although the toner cartridge 5 as the developer storage body is configured to be detachable (replaceable) and to supply the toner to the image forming unit 2, it is also possible that the developer storage body includes a collection container for collecting waste toner (i.e., a waste developer) as well as the toner cartridge 5.
Further, the image forming apparatus 1 of the second embodiment is the same as that of the first embodiment except the shape of the film member 51 of the toner cartridge 5, and therefore explanations of configuration and operation of the image forming apparatus 1 will be omitted.
In the second embodiment, a side end edge of the film member 51 in the longitudinal direction contacts the side wall 31 of the toner cartridge 4. Further, slits 53 are formed on the side end edge of the film member 51. To be more specific, a plurality of (in this example, four) slits 53 are arranged in a widthwise direction of the film member 51. Each slit 53 extends in the longitudinal direction of the film member 51, i.e., the longitudinal direction of the toner cartridge 5.
The other side end edge of the film member 51 is apart from the side wall 41 as in the first embodiment. However, it is also possible that this side end edge of the film member 51 contacts the side wall 41 and has slits 53.
The function of the toner cartridge 5 of the second embodiment is substantially the same as that of the first embodiment. To be more specific, in the second embodiment, the film member 51 rotates in such a manner that the side end edge of the film member 51 contacts the side wall 31. That is, the film member 51 rotates contacting the side wall 31, the inner circumferential surface of the inner case 4 and the inclined portions 32 and 42. Therefore, the film member 51 scrapes off the toner from the side wall 31, the inner circumferential surface of the inner case 4 and the inclined portions 32 and 42, and supplies the toner to the image forming unit 2 via the opening 45 and the toner supply opening 35.
As described above, according to the second embodiment, the film member 51 is configured to contact at least one of the side walls 31 and 41. Therefore, the film member 51 does not only scrape off the toner adhering to the inclined portions 32 and 42, but also scrapes off the toner adhering to the side wall(s) of the toner cartridge 5. The scraped toner is supplied to the image forming unit 2. Thus, it becomes possible to effectively prevent the toner from remaining at both ends of the toner cartridge 5.
Further, the slits 53 are formed on a contact portion (i.e., the side end edge) of the film member 51 contacting the side wall 31, and therefore the contact portion can be easily deformed according to the shape of the inclined portion 32 and the side wall 31. Thus, the toner can be smoothly scraped off from the inclined portion 32 and the side wall 31.
The present invention is applicable to an image forming apparatus such as a printer, a facsimile machine, a copier, or a combined machine having a plurality of functions thereof.
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 |
|---|---|---|---|
| 2010-094706 | Apr 2010 | JP | national |
