Patent Grant
7974550
The present invention restates to an image forming apparatus, an image forming structural body, a method of mounting an image forming structural body, and a method of pulling out an image forming structural body.
The present invention is directed to an image forming apparatus comprising: a conveyer that conveys a developer image or a transfer medium to which the developer image is transferred; an image carrier that carries the developer image transferred to the conveyer or the transfer medium which the conveyer conveys; a latent image forming unit that forms the latent image on the image carrier; a developing unit that develops the latent image formed on the image carrier and forms a developer image; a transfer unit that transfers the developer image formed on the image carrier; and a restricting unit that restricts the movement of the image carrier and the latent image forming unit in at least two directions and a rotational direction of the image carrier.
Next, embodiments of the present invention are explained in conjunction with the drawings.
A sheet feeding device 18 is provided in a lower portion of the image forming apparatus body 12. The sheet feeding device 18 includes a sheet stacking device 20 in which sheets used as transfer mediums are stacked, a pick-up roller 22 which picks up the sheets stacked in the sheet stacking device 20, a feed roller 24 and a retardation roller 26 which feed the sheets while sorting. The sheet stacking device 20 is detachably arranged with respect to the image forming apparatus body 12 such that the sheet stacking device 20 can be pulled out in the sheet-front-surface-side direction in the drawing. Sheets such as ordinary sheets or OHP sheets, for example, are stored in the sheet stacking device 20 in a stacked state.
A sheet supply passage 28 is provided approximately along the vertical direction in the vicinity of one end (in the vicinity of the left side in the drawing) of the image forming apparatus body 12. To the sheet supply passage 28, a transport roller 29, a registration roller 30, a second transfer roller 32, a fixing device 34 and an exit roller 36 are provided. The registration roller 30 temporarily stops a sheet fed out to the sheet supply passage 28 and feeds the sheet to the second transfer roller 32 at proper timing. The fixing device 34 is constituted of a heating roller 34a and a pushing roller 34b, wherein heat and pressure are applied to a sheet passing between the heating roller 34a and the pushing roller 34b thus fixing a toner image on the sheet. The second transfer roller 32 is made detachable with respect to the image forming apparatus body 12 as a second transfer structural body 33 and can be pulled out in the sheet-front-surface-side direction in
An exit portion 38 is arranged in an upper portion of the image forming apparatus body 12. A sheet on which a developer image is fixed is conveyed to the exit portion 38 by the above-mentioned exit roller 36 and is stacked in the exit portion 38. Accordingly, the sheets in the sheet stacking device 20 are sequentially conveyed to the exit portion 38 through a C-shaped path.
Four toner bottles 40 are provided to another end side (to the right side in the drawing) of the image forming apparatus body 12, for example. The toner bottles 40 store toners of yellow, magenta, cyan and black therein respectively, and supply the toners to the image forming section 16 by way of toner supply passages not shown in the drawing.
Each of the plural image forming sections 16 forms an image forming structural body 48 as one unit structure, while the respective image forming sections 16 are mounted in the image forming apparatus body 12 in an independently detachable manner. The image forming structural body 48 is pulled out of the image forming apparatus body 12 in such a way that the image forming structural body 48 is once moved downwardly and, thereafter, is pulled out in the sheet-front-surface-side direction in
The transfer structural body 15 includes the intermediate transfer belt 14 as mentioned above. The transfer structural body 15 also includes a plurality of support rollers 42 which supports the intermediate transfer belt 14, plural transfer members 50 which is constituted of first transfer rollers, for example, for transferring toner images formed by the plural image forming sections 16 respectively to the intermediate transfer belt 14, and an intermediate belt cleaning device 44 for cleaning the intermediate transfer belt 14. The transfer structural body 15 is made detachable with respect to the image forming apparatus body 12 and can be pulled out in the sheet-front-surface-side direction in
The intermediate transfer belt 14 is supported by the plural support rollers 42 and a belt surface of the intermediate transfer belt 14 on a side on which the image forming sections 16 are arranged is arranged obliquely with respect to the horizontal direction. One of the support rollers 42 constitutes a back-up roller for the second transfer roller 32. Further, in the vicinity of the upper end of the intermediate transfer belt 14, the intermediate transfer belt cleaning device 44 is arranged and another one of the support rollers 42 is used as a back-up roller for the cleaning device 44. Still further, above the intermediate transfer belt 14, a tension roller 46 is arranged and the tension roller 46 applies proper tension to the intermediate transfer belt 14.
The image forming section 16 is integrally formed as the image forming structural body 48 as previously mentioned. A photoreceptor 52 which is used as an image carrier, a charging device 54 for charging the photoreceptor 52 and is constituted of a roller, for example, a latent image forming member 56 and forms a latent image by optical writing in the photoreceptor 52, a developing device 58 for developing a latent image written in the photoreceptor by the latent image forming member 56 for forming a developer image, and a cleaning device 60 which cleans the toner remaining on the photoreceptor 52 after the transfer of an image are mounted in the image forming structural body 48.
The image forming structural body 48 is constituted by joining a photoreceptor unit 62 and a developing unit 64 which are separable from each other. With respect to the photoreceptor unit 62, the photoreceptor 52, a charging device 54, a latent image forming member 56 and the cleaning device 60 are housed in a first housing 66. With respect to a developing unit 64, a developing device 58 is housed in a second housing 68. Further, the first housing 66 and the second housing 68 are joined to each other to form the separable image forming structural body 48.
In this embodiment, although the photoreceptor 52, the charging device 54, the latent image forming member 56, the developing device 58, and the cleaning device 60 are integrally formed as the image forming structural body 48, it is sufficient that the photoreceptor 52 and the latent image forming member 56 are integrally formed as a structural body. It is not always necessary to integrally form the charging device 54, the developing device 58 and the cleaning device 60 into the image forming structural body 48. For example, the charging device 54, the developing device 58 and the cleaning device 60 may be mounted on the image forming apparatus body 12 side.
As a latent image forming member 56, an LED (light emitting diode) is used, for example.
A photoreceptor 52 has an approximately cylindrical shape and bearings 53, 53 which constitute supporting members are respectively mounted on both sides of the photoreceptor 52. Bearings 53, 53 have a diameter larger than a diameter of the photoreceptor 52 and support the photoreceptor 52 so that the photoreceptor 52 is rotatable about a rotational center 52a as the center of rotation. The bearings 53, 53 are mounted on the image forming structural body 48 in a state that portions of the bearings 53, 53 project to the outside from the image forming structural body 48.
On one of the bearings 53, 53, the photoreceptor gear 110 is mounted at a position opposite to the photoreceptor 52 for transmitting driving to the photoreceptor 52 such that the photoreceptor gear 110 is arranged outside the image forming structural body 48. The photoreceptor gear 110 is rotated together with the photoreceptor 52 upon reception of transmission of the driving from a drive gear 116 which is mounted on a side plate 112 of the image forming apparatus body 12 using a bearing 114.
The developing device 58 adopts two-component system, for example, wherein a developer constituted of toner and carrier is used. For example, the developing device 58 includes two augers 70, 72 arranged parallel to each other in the horizontal direction, and a developing roller 74 which is arranged at an upper and oblique position from the auger 72 on an exit side and agitates a developer using the augers 70, 72. The developing device 58 supplies the agitated developer to the developing roller 74. A magnetic brush is formed on the developing roller 74 due to the carrier and the developing roller 74 transfer the toner adhered to the carrier by the magnetic brush thus developing a latent image formed on the photoreceptor 52 using the toner. In the developing device 58 of this embodiment which adopts the two-component system, the developing roller 74 is arranged above the augers 70, 72 so that the accumulation of the developer can be prevented and the developer can be uniformly agitated whereby the developer can maintain the developing property.
The cleaning device 60 is, for example, constituted of a toner scraping portion 76 formed of a blade, and a collecting portion 78 for collecting the toner scraped in the toner scraping portion 76.
The image forming structural bodies 48 are used as a pushing section when the image forming structural bodies 48 are mounted in the image forming apparatus body 12. The image forming structural bodies 48 are respectively biased using springs 100 formed of a resilient body, for example, in the direction of a transfer structural body housing 86 described later, and are pushed to the transfer structural body housing 86. One end side of each spring 100 is fixed to the image forming apparatus body 12, while the other end side of the spring 100 is brought into contact with the image forming structural body 48 directly or indirectly by way of other members.
The transfer structural body 15 includes the transfer structural body housing 86, on which the support rollers 42, the transfer members 50 and the tension roller 46 are rotatably mounted. The intermediate transfer belt 14 is supported on the support rollers 42. Further, in the transfer structural body 15, an intermediate transfer belt cleaning device 44 is detachably mounted.
The transfer structural body housing 86 includes a sheet-front-surface-side side plate 88 and a sheet-depth-side side plate 90 in
Four downwardly projecting portions 118 used as second restricting members are formed on portions of the notched portions 94 formed in the side plate 88. The number of the downwardly projecting portions 118 is equal to the number of the image forming structural bodies 48 used for image forming. Also on the notched portions formed in the side plate 90, four projecting portions 118 are formed in the same manner as the side plate 88. The projecting portions 118 are arranged to be positioned downstream of the photoreceptor 52 in the rotational direction of the photoreceptor 52 with respect to the rotational center 52a of the photoreceptor 52. That is, the projecting portions 118 are provided at a position where the projecting portions 118 can restrict the movement of the image forming structural body 48 toward the downstream side in the rotational direction of the photoreceptor 52.
For positioning the transfer structural body 15 and the image forming structural body 48 constituted in such a manner in the image forming apparatus body 12, the transfer structural body 15 is positioned with respect to the image forming apparatus body 12 and, thereafter, the plurality of image forming structural bodies 48 are positioned with respect to the positioned transfer structural body 15. The positioning of the transfer structural body 15 with respect to the image forming apparatus body 12 is, for example, performed with respect to a frame (not shown in the drawing) of the image forming apparatus body 12.
The positioning of the image forming structural body 48 with respect to the transfer structural body 15 is performed such that the previously-mentioned bearings 53, 53 are respectively pushed to the side plates 88, 90. That is, portions of the bearings 53, 53 projecting from the image forming structural bodies 48 are respectively brought into contact with the notched portions 94 formed in the side plates 88, 90 and, in this state, the image forming structural bodies 48 are pushed to the side plates 88, 90 using the springs 100, 100 which constitute the pushing section.
As described above, in this embodiment, the plurality of image forming structural bodies 48, 48, 48 are pushed to the transfer structural body housing 86 which constitutes one member and are positioned with respect to the transfer structural body housing 86 which constitutes one member.
When the image forming structural bodies 48 are pushed to the transfer structural body housing 86 using the springs 100, 100, the bearings 53, 53 are respectively brought into contact with two portions respectively formed on the side plates 88, 90 such as a peripheral portion 104 extending in the approximately vertical direction and a peripheral portion 106 extending in the approximately horizontal direction and hence, the image forming structural body 48 is positioned at the rotational center 52a of the photoreceptor 52 by reference to the side plates 88, 90.
When the image forming structural body 48 is positioned in the image forming apparatus body 12 by way of the transfer structural body housing 86, the photoreceptor gear 110 and the drive gear 116 are meshed with each other so that rotational driving can be transmitted to the photoreceptor 52 from the image forming apparatus body 12 side by way of the drive gear 116 and the photoreceptor gear 110.
Further, when the image forming structural bodies 48 are positioned in the image forming apparatus body 12, not only the bearing 53 is brought into contact with the peripheral portion 104 and the peripheral portion 106, but also an end portion 48a of the image forming structural body 48 on a side opposite to a side where the bearing 53 is positioned is brought into contact with the projecting portion 118. Accordingly, the image forming structural body 48 is brought into contact with the side plate 88 at three points or three portions consisting of the peripheral portion 104, the peripheral portion 106 and the projecting portion 118 in a sheet-front-surface-side shown in
As described above, the image forming apparatus 10 performs image forming in a state that the transfer structural body 15 and the respective image forming structural bodies 48 are mounted in the image forming apparatus body 12. When the image forming apparatus 10 performs image forming, the respective photoreceptors 52 are rotated in the counterclockwise direction indicated by an arrow as shown in
In this embodiment, four image forming structural bodies 48 are pushed to the transfer structural body housing 86 so as to position the four image forming structural bodies 48 with respect to the transfer structural body 15. However, the respective image forming structural bodies 48 may be positioned with respect to the image forming apparatus body 12 side such as a frame of the image forming apparatus body 12, for example.
In this embodiment, as mentioned previously, the projecting portion 118 restricts the movement of the image forming structural body 48 in the rotational direction about the rotational center 52a of the photoreceptor 52 as the center of rotation. Further, by restricting the movement of the image forming structural body 48 in the rotational direction, the projecting portion 118 restricts the change of the distance L along the surface of the photoreceptor 52 between a writing position “a” at which the latent image forming member 56 performs writing of a latent image on the photoreceptor 52 and a transfer position “b” at which the transfer member 50 transfers the toner image carried by the photoreceptor 52 to the sheet.
The distance L is decreased when the image forming structural body 48 is rotated right-handedly (in the counterclockwise direction) in the drawing and is increased when the image forming structural body 48 is rotated left-handedly (in the clockwise direction) in the drawing. When the distance L is decreased, a developer image reaches to the transfer position “b” earlier than predetermined timing using the exposure time as the reference. On the other hand, when the distance L is increased, the developer image reaches the transfer position later than predetermined timing using the exposure time as the reference. Further, both when the distance L is increased and when the distance L is decreased, a toner image is transferred to the intermediate transfer belt 14 at timing different from the predetermined timing thus causing the occurrence of an image defect such as color shifting or the like on an image finally formed on a sheet.
As described above, in the image forming apparatus 10, the side plates 88, 90, the projecting portion 118, the bearings 53, 53 and the springs 100, 100 are used as a restricting unit, wherein these members restrict the movement of the image forming structural body 48 in two directions, that is, the approximately vertical direction and the approximately horizontal direction and, at the same time, these members restrict the movement of the photoreceptor 52 in the rotational direction in the image forming structural body 48.
In the image forming apparatus 10 having such a constitution, to pull out the image forming structural body 48 of the image forming apparatus body 12, the pushing pressure of the bearings 53, 53 applied to the side plates 88, 90 using the spring 100, 100 is removed before pulling out the image forming structural body 48 of the image forming apparatus body 12. Further, the projecting portion 118 and the image forming structural body 48 are made spaced-apart from each other, thus removing the restriction imposed on the rotation of the image forming structural body 48 applied by the projection portion 118 and, at the same time, removing the restriction imposed on the change of the distance L (see
On the other hand, in mounting the image forming structural body 48 in the image forming apparatus body 12, the image forming structural body 48 is inserted into the image forming apparatus body 12 and, thereafter, the projecting portion 118 and the end portion 48a of the image forming structural body 48 are brought into contact with each other, and a state that the image forming structural body 48 is pushed to the transfer structural body housing 86 is held using springs 100, 100. In this state, the projecting portion 118 restricts the rotation of the image forming structural body and, at the same time, restricts the change of the distance L (see
Two projecting portions 130 are mounted on each image forming structural body 48 such that, for example, one projecting portion 130 is mounted on a sheet-front-surface side in the axial direction of the photoreceptor 52 in
The positioning mechanism 140 is respectively used as a first biasing member and includes a spring 144 made of an elastic material. One end portion of the spring 144 is fixed to the latent image forming member 56 and the other is fixed to an inner wall of the image forming structural body 48, and the spring 144 biases the latent image forming member 56 in the direction toward the photoreceptor 52. By biasing the latent image forming member 56, the projecting portions 142, 142 are pushed to the bearings 53, 53.
The positioning mechanisms 140 are respectively used as second biasing members and each of the positioning mechanisms 140 includes a spring 146 made of an elastic material. One end of the spring 146 is fixed to a surface of the latent image forming member 56 which is substantially perpendicular to the surface of the latent image forming member 56 to which the spring 144 is fixed, and the other end of the spring 146 is fixed to the inside of the image forming structural body 48. The latent image forming member 56 is pushed to an inclined inner wall 48b of the image forming structural body 48 by the spring 146 and is positioned with respect to the image forming structural body 48.
In a state that the latent image forming member 56 is positioned by the positioning mechanisms 140, 140, the latent image forming member 56 have portions which are not brought into contact with the image forming structural body 48 and other members on an outer side surface thereof, and a space 148 which is not occupied by other members is formed around the image forming member 56. The space 148 can store air for cooling the latent image forming member 56 which is heated to a high temperature due to writing, for example, or can be used as a flow passage for allowing the flow of a cooling medium such as air, for example, for cooling the latent image forming member 56. Here, parts identical to the parts used in the first embodiment are given the same numbers in
As has been described heretofore, the present invention is applicable to image forming apparatuses such as a photocopying machine, a facsimile device and a printer, an image forming structural body used for these image forming apparatuses, a mounting method of the image forming structural body, and a method of pulling out the image forming structural body.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-366440 | Dec 2005 | JP | national |
| 2006-296104 | Oct 2006 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2006/325326 | 12/20/2006 | WO | 00 | 6/20/2008 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2007/072839 | 6/28/2007 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5111244 | Koyama et al. | May 1992 | A |
| 20050196194 | Suda et al. | Sep 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| A-9-95013 | Apr 1997 | JP |
| A-2001-066968 | Mar 2001 | JP |
| A-2001-142274 | May 2001 | JP |
| A-2003-168132 | Jun 2003 | JP |
| A-2003-195724 | Jul 2003 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20090162087 A1 | Jun 2009 | US |
