The present invention relates to an image forming apparatus such as an electro-photographic copying machine and an electro-photographic printer.
It is known that a conventional electro-photographic image forming apparatus has the configuration which transmits a rotational driving force of a driving source to the photosensitive member by coupling a driving source side coupling to a photosensitive member side coupling in order to rotate the photosensitive member.
Further, Japanese Laid-Open Patent Application Publication No. 2009-75268 discloses the configuration in which the driving source side coupling is coupled to the photosensitive member side coupling or the driving source side coupling is decoupled from the photosensitive member side coupling according to the selection between a color mode and a monochrome mode. Specifically, the driving source side coupling is coupled to the photosensitive member side coupling or the driving source side coupling is decoupled from the photosensitive member side coupling by the driving source side coupling being placed close to the photosensitive member side coupling or by the driving source side coupling being separated from the photosensitive member side coupling, respectively. As a result, the photosensitive members of the respective colors are rotated by a single motor in order to reduce the cost, and the photosensitive members for color are not rotated in the monochrome mode in order to suppress the abrasion of the photosensitive members for color.
There exists a following problem for the configuration disclosed in which the driving source side coupling is coupled to the photosensitive member side coupling or the driving source side the coupling is decoupled from the photosensitive member side coupling according to the selection between a color mode and a monochrome mode as disclosed in Japanese Laid-Open Patent Application Publication No. 2009-75268.
That is, in decoupling the driving source side coupling from the photosensitive member side coupling, when the driving source side coupling is separated from the photosensitive member side coupling, the driving source side coupling may be inclined due to the driving source side coupling being insufficiently supported by the photosensitive member side coupling as depicted in
A representative configuration of the image forming apparatus of the present invention includes:
a main body of the image forming apparatus;
a first drum cartridge which has a first photosensitive drum on which a color toner image is formed, the first drum cartridge being configured to be attached to the main body by being moved and inserted into the main body from an outside of the main body in a direction of a rotational axis of the first photosensitive drum;
a second drum cartridge which has a second photosensitive drum on which a black toner image is formed, the second drum cartridge being configured to be attached to the main body by being moved and inserted into the main body from an outside of the main body in the direction of the rotational axis;
a driving source provided in the main body, the driving source being configured to generate a driving force for rotating the first photosensitive drum and the second photosensitive drum;
a main body gear provided in the main body, the main body gear being configured to transmit the driving force from the driving source to the first drum cartridge, the main body gear being configured to rotate by the driving force;
a coupling gear which is integrally molded with a main body side coupling portion and a main body side gear portion, the main body side coupling portion being configured to be coupled to a drum side coupling portion of the first drum cartridge, the main body side gear portion being configured to mesh with the main body gear, the coupling gear being configured to rotate by the driving force being transmitted from the driving source to the main body side gear portion via the main body side gear; and moving means for moving the coupling gear to a coupling position where the drum side coupling portion and the main body side coupling portion are coupled to each other and to a decoupling position where the drum side coupling portion and the main body side coupling portion are decoupled from each other, wherein when a color image is formed, the moving means moves the coupling gear to the coupling position and when a monochrome image is formed, the moving means moves the coupling gear to the decoupling position.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, the overall configuration of the image forming apparatus according to the first embodiment of the present invention will be described together with the operation during an image formation with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described below are not intended to limit the scope of the present invention to them unless otherwise specified.
The image forming apparatus according to the present embodiment is of an electro-photographic type. In the image forming apparatus, the toners of four colors of yellow Y, magenta M, cyan C, and black K are transferred onto an intermediate transfer belt, and then an image is transferred onto a sheet to form an image. In the following description, members using the toners of the above colors are basically suffixed with Y, M, C, and K, respectively. However, when differentiation of the members using the suffixes Y, M, C, and K is not necessary, these suffixes will be appropriately omitted since the configuration and the operation of each member are substantially the same as those of the other members except for the color of the toner.
As shown in
The image forming portion includes the photosensitive drums 1 (1Y, 1M, 1C, and 1K), the charging rollers 31 (31Y, 31M, 31C, and 31K) which charges the surface of the photosensitive drums 1, the developing devices 33 (33Y, 33M, 33C, and 33K), the primary transfer rollers 2 (2Y, 2M, 2C, and 2K), the laser scanner units 32 (32Y, 32M, 32C, and 32K), the drum cleaners 34 (34Y, 34M, 34C, and 34K), and the intermediate transfer unit 40.
The intermediate transfer unit 40 includes the intermediate transfer belt 3, the secondary transfer roller 26, the secondary transfer counter roller 4, the steering roller 80, the tension roller 19, and the belt cleaner 18. The intermediate transfer belt 3 (intermediate transfer member) is an endless belt stretched around the secondary transfer counter roller 4, the steering roller 80, the tension roller 19 and the like. The intermediate transfer belt 3 is rotated by the rotation of the secondary transfer counter roller 4 which is driven by the driving source.
Next, the image forming operation will be described. When the control portion (not shown) receives an image forming job signal, the sheet S stacked and stored on the sheet stacking portion 81 is sent by the feeding roller 82 and the conveying roller 83 to the secondary transfer portion configured by the secondary transfer roller 26 and the secondary transfer counter roller 4.
On the other hand, in the image forming portion, firstly, the surface of the photosensitive drum 1 is uniformly charged by the charging roller 31. Thereafter, the laser scanner unit 32 irradiates the surface of the photosensitive drum 1 of each color with a laser beam generated by a light source (not shown) according to the image data transmitted from an external device (not shown) or the like so that an electrostatic latent image is formed on the surface of the photosensitive drum 1.
Thereafter, toners of respective colors are attached to the electrostatic latent image formed on the surface of the photosensitive drum 1 by the developing device 33 to form a toner image on the surface of the photosensitive drum 1. The toner image formed on the surface of the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 3 by applying a primary transfer bias to the primary transfer roller 2. As a result, a full color toner image is formed on the surface of the intermediate transfer belt 3.
Thereafter, as the intermediate transfer belt 3 rotates, the toner image is sent to the secondary transfer portion. Then, at the secondary transfer portion, a secondary transfer bias is applied to the secondary transfer roller 26 so that the toner image on the intermediate transfer belt 3 is transferred onto the sheet S.
That is, the photosensitive drums 1Y, 1M, and 1C (examples of the first photosensitive drum) bears a color toner image, and the photosensitive drum 1K (an example of the second photosensitive drum) bears a black toner image. The primary transfer rollers 2Y, 2M, 2C (first transfer members) transfer the toner images born on the photosensitive drums 1Y, 1M, 1C onto the intermediate transfer belt 3, and the primary transfer roller 2K (second transfer member) transfers the toner image born on the photosensitive drum 1K onto the intermediate transfer belt 3. The toner images born on the photosensitive drum 1 are temporarily transferred onto the intermediate transfer belt 3.
Next, the sheet S on which the toner image has been transferred is heated and pressurized at the fixing device 35, whereby the toner image on the sheet S is fixed to the sheet S. Thereafter, the sheet S on which the toner image is fixed is discharged to a discharge portion (not shown).
The toner attached to the surface of the photosensitive drum 1 after the primary transfer is scraped off and removed by the drum cleaner 34. On the other hand, the toner attached to the intermediate transfer belt 3 after the secondary transfer is scraped off and removed by the belt cleaner 18.
The configuration according to the present embodiment can be similarly applied to an image forming apparatus using a drum cartridge in which the photosensitive drum 1 and the charging device 2 and the drum cleaner 34 are integrated and which is to be mounted on the main body of the image forming apparatus A. The drum cartridge can be attached to and detached from the apparatus main body by inserting and pulling out the drum cartridge respectively at the side surface of the main body of the image forming apparatus A. When replacing the photosensitive drum 1, the drum cartridge is removed from the apparatus main body and replaced.
The image forming apparatus A can execute a full color mode for forming a full color image described above and a monochrome mode for forming a monochrome image using only black toner. Hereinafter, the configuration of the full color mode and the configuration of the monochrome mode will be described.
As shown in
As shown in
For example, the photosensitive drum 1 always abuts on the drum cleaner 34 when the photosensitive drum 1 is rotated. As a result, the surface of the photosensitive drum 1 is abraded by the drum cleaner 34. As described above, by stopping the rotation of the photosensitive drums 1 which are not used during image formation, the photosensitive drums 1 are not rubbed by the drum cleaner 34 when the photosensitive drums 1 are not used. Thus, it can be suppressed for the photosensitive drum 1 to be consumed.
Next, the configuration of the driving portion for driving the photosensitive drum 1 will be described.
Next, the photosensitive member coupling 42 and the gear coupling 41 will be described. Hereinafter, the description of the photosensitive member couplings 42Y to 42C and the gear couplings 41Y to 41C for the color photosensitive drums and the description of the photosensitive member coupling 42K and the gear coupling 41K for the monochrome photosensitive drum will be separately made.
Firstly, the photosensitive member couplings 42Y to 42C and the gear couplings 41Y to 41C will be described. Since each of the configurations of the stations Y, M and C is the same as those of the other stations, the photosensitive member coupling 42Y and the gear coupling 41Y will be described as an example. As shown in
Specifically, the gear coupling 41Y is provided on the side plate 50 disposed on the back side of the image forming apparatus A. When the photosensitive drum 1Y is attached to the image forming apparatus A, the photosensitive member coupling 42Y engages with the gear coupling 41Y. In this case, it is not necessary for the photosensitive member coupling 42Y to mesh with the gear coupling 41Y, and it suffices that the photosensitive member coupling 42Y is in contact with the gear coupling 41Y. For example, at this state, the gear coupling 41Y is driven to rotate by the driving source, and the photosensitive member coupling 42Y may be coupled to the gear coupling 41Y by this rotation.
The gear coupling 41Y is a member in which the gear portion 41a and the coupling portion 41b are integrally formed, and the main body gear 210 meshes with the gear portion 41a (see
<Switching Configuration between Coupling and Decoupling States>
Next, the configuration for switching between the coupling state and a decoupling state between the gear couplings 41Y, 41M and 41C, and the photosensitive member couplings 42Y, 42M and 42C will be described. In the following description, only the configuration for switching between the coupling state and the decoupling state between the gear coupling 41Y and the photosensitive member coupling 42Y will be described since the configurations of the gear couplings 41M and 41C are the same as that of the gear coupling 41Y and the configurations of the photosensitive member couplings 42M and 42C are the same as that of the photosensitive member coupling 42Y.
As shown in
The side plate 50 is provided in the vicinity of the slider 44. Further, the cam holder 46 (holding member) is attached and fixed to the side plate 50. The cam holder 46 encloses and holds the cam link 43 (abutting member). The cam link 43 is provided so as to abut on the gear coupling 41Y. The boss portion 43a (see
With reference to
As shown in
When decoupling the gear coupling 41Y from the photosensitive member coupling 42Y, the slider driving gear 45 is rotated in the direction of the arrow R1 shown in
Next, as shown in
When coupling the gear coupling 41Y to the photosensitive member coupling 42Y, the motor (not shown) is reversely rotated so that the slider driving gear 45 is rotated in the direction opposite to the arrow R1 shown in
Next, as the slider 44 moves, the cam link 43 rotates in the direction opposite to the direction of the arrow R2 shown in
That is, the cam link 43, the cam holder 46, and the motor (not shown) function as moving means for moving the gear coupling 41 between the coupling position where the coupling portion 41b (an example of a main body side coupling portion) of the gear coupling 41 is coupled to the photosensitive member coupling 42 and the decoupling position where the coupling portion 41b is decoupled from the photosensitive member coupling 42 by the coupling portion 41b being retracted from the coupling position in the thrust direction. A control portion (not shown) controls the driving of the motor (not shown) for rotating the slider driving gear 45 (and the cam link 43), and controls this moving means.
No matter when the gear coupling 41Y is coupled to the photosensitive member coupling 42Y or when the gear coupling 41Y is decoupled from the photosensitive member coupling 42Y, the gear portion 41a (an example of a main body side gear portion) of the gear coupling 41Y meshes with another gear, that is, the main body gear 210, for example. For this reason, when the motor (not shown) rotates in the state where the gear coupling 41Y is decoupled from the photosensitive member coupling 42Y, the gear coupling 41Y rotates and the photosensitive member coupling 42Y does not rotate.
As described above, the photosensitive drums 1Y, 1M and 1C remain in the state where the photosensitive drums 1Y, 1M and 1C do not rotate even when the gear coupling 41 rotates by decoupling the gear couplings 41Y, 41M and 41C from the photosensitive member couplings 42Y, 42M and 42C, respectively in the monochrome mode. Therefore, it is possible to reduce the cost by rotating the photosensitive drums 1 of respective colors by one motor, as well as to suppress the abrasion by making the photosensitive drums 1Y, 1M and 1C for color remain in the state where the photosensitive drums 1Y, 1M and 1C do not rotate in the monochrome mode.
Next, the support configuration of the gear couplings 41Y, 41M and 41C will be described. In the following description, only the supporting configuration of the gear coupling 41Y is described since the configuration of the gear couplings 41M and 41C have the same configuration as that of the gear coupling 41Y.
As shown in
As shown in
Here, the gear coupling 41 is moved between the coupling position and the decoupling position by the moving means. Therefore, the gear coupling 41 slides between the coupling position and the decoupling position with the gear portion 41a being meshed with the main body gear 210. However, the present invention is not limited to this configuration. For example, the gear portion 41a may be decoupled from the main gear 210 according as the gear coupling 41 moves from the coupling position to the decoupling position.
As shown in
As shown in
As shown in
On the other hand, the front bearing 48 is located at a position corresponding to the large outer diameter portion 41d of the gear coupling 41Y (at a position where the front bearing 48 overlaps with the large outer diameter portion 41d in the direction orthogonal to the thrust direction). Further, the large outer diameter portion 41d is fitted with the front bearing 48. As a result, the gear coupling 41 is supported by the front bearing 48. That is, according as the gear coupling 41Y moves from the coupling position where the gear coupling 41Y is coupled to the photosensitive member coupling 42Y to the decoupling position where the gear coupling 41Y is decoupled from the photosensitive member coupling 42Y, the front bearing 48 gets fitted to the large outer diameter portion 41d so that the gear coupling 41 is supported by the front bearing 48.
As described above, by supporting the gear coupling 41 with the front bearing 48 when the gear coupling 41 is decoupled from the photosensitive member coupling 42, the gear coupling 41 is suppressed from being tilted. Therefore, it is possible to suppress a failure in the meshing between the gear coupling 41 and another gear (not shown) at the meshing portion, which enables to suppress the deterioration of the rotational accuracy and the generation of abnormal sound when the gear coupling 41 rotates.
Further, when the gear coupling 41 is coupled to the photosensitive member coupling 42, the front bearing 48 does not support the gear coupling 41. That is, the gear coupling 41 is not supported at the three points of the rear bearing 47, the front bearing 48 and the photosensitive member coupling 42. As a result, it is possible to suppress the occurrence of poor fitting between the members due to the influence of tolerance.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2018-120554, filed Jun. 26, 2018, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2018-120554 | Jun 2018 | JP | national |