The present invention relates to an electro-photographic process unit removably attached to a copier or a printer for forming images by the electro-photographic method and an image forming apparatus.
In recent years, in an image forming apparatus of the electro-photographic method such as a copier or a printer, there is an apparatus using an electro-photographic process unit (hereinafter abbreviated to EPU) integrally incorporated with a photosensitive drum and a main charger or a cleaner around the photosensitive drum which can be attached removably to the apparatus body. The EPU, when taken out from the apparatus body at time of maintenance, is put on the workbench around the apparatus body. At this time, to prevent the bottom of the EPU from touching directly the workbench or tools placed in the neighborhood of the workbench, conventionally, there is an apparatus in which the housing of the EPU is equipped with fixed legs.
Particularly, in an EPU equipped with a developing device and a toner density sensor at the bottom, when the EPU equipped with legs on the housing is put on the workbench around the apparatus body, the toner density sensor is prevented from touching the workbench or tools on the workbench and being damaged.
On the other hand, in recent years, further miniaturization of the image forming apparatus is required and it is also required to make the components themselves of the image forming apparatus smaller and reduce the spaces between the components. As a result, the space around the EPU is restricted and in the neighborhood of the EPU, it is necessary to closely arrange a laser optical unit for exposing a photosensitive drum and a transfer unit.
However, if the space around the EPU is reduced like this, when inserting or removing the EPU from the apparatus body, it is interrupted by the legs fixed to the housing. Therefore, although the housing is made smaller, around the EPU, it is necessary to provide a space for inserting the legs of the housing, thus it is an obstacle to miniaturization of the image forming apparatus.
Therefore, in the image forming apparatus using the EPU inserted or removed from the apparatus body, an electro-photographic process unit for, when putting the EPU on the workbench outside the apparatus body, preventing the bottom of the EPU from touching the workbench, reducing the space for passing the housing legs when inserting or removing the EPU from the apparatus body, thereby realizing further miniaturization of the image forming apparatus and an image forming apparatus are desired.
Therefore, an effect of the present invention, in the image forming apparatus using the EPU, is to reduce the space for passing the housing legs of the EPU and realize miniaturization of the main body of the image forming apparatus.
To accomplish the above effect, according to the embodiment of the present invention, there is provided An electro-photographic process unit comprising: an image carrying member on which a toner image is formed; a case member removably attached to a main body of an image forming apparatus to support the image carrying member; and at least one leg member provided on the case member, rotatable when the case member is mounted in the main body of the image forming apparatus and fixed when the case member is put on a loading face outside the main body of the image forming apparatus, to support the case member.
The embodiment of the present invention will be explained in detail with reference to the accompanying drawings.
EPUs 2Y, 2M, 2C and 2K respectively have photosensitive drums 11Y, 11M, 11C and 11K which are image carrying members. To the primary transfer positions of intermediate transfer belt 10 opposite to photosensitive drums 11Y, 11M, 11C and 11K, a primary transfer voltage is applied by primary transfer rollers 21Y, 21M, 21C and 21K and toner images on photosensitive drums 11Y, 11M, 11C and 11K are primarily transferred to the intermediate transfer belt.
Intermediate transfer belt 10 is stretched and suspended by drive roller 10c and secondary transfer opposite roller 10a, and to the secondary transfer position where secondary transfer roller 17 and secondary transfer opposite roller 10a are arranged opposite to each other, a secondary transfer voltage is applied by secondary transfer roller 17 via sheet of paper P, and a toner image on intermediate transfer belt 10 is secondarily transferred to sheet of paper P. On the downstream side of secondary transfer roller 17 of intermediate transfer belt 10, belt cleaner 10b is installed.
In EPUs 2Y, 2M, 2C and 2K, around photosensitive drums 11Y, 11M, 11C and 11K, in the rotational direction of arrow m, chargers 14Y, 14M, 14C and 14K which are charging members, developing devices 13Y, 13M, 13C and 13K which are developing members, and photoconductor cleaners 12Y, 12M, 12C and 12K which are cleaning members are arranged. Between chargers 14Y, 14M, 14C and 14K around photosensitive drums 11Y, 11M, 11C and 11K and developing devices 13Y, 13M, 13C and 13K, exposure light is irradiated by laser exposure device 50 which is an exposing member. Chargers 14Y, 14M, 14C and 14K, laser exposure device 50, developing devices 13Y, 13M, 13C and 13K, and photoconductor cleaners 12Y, 12M, 12C and 12K around photosensitive drums 11Y, 11M, 11C and 11K compose an image forming mechanism.
Next, the structure of EPUs 2Y, 2M, 2C and 2K will be described in detail. EPUs 2Y, 2M, 2C and 2K have the same structure, so that the common numerals will be used for explanation. As shown in FIGS. 2 to 5-3, on the bottom of housing 22 of each of EPUs 2Y, 2M, 2C and 2K, auto-toner sensor 23, for example, for magnetically detecting the toner density of developing devices 13 is projected. Further, in the four corners of the side of the bottom of housing 22 of each of EPUs 2Y, 2M, 2C and 2K, support legs 24 which are leg members are attached rotatably.
As shown in
On the other hand, when EPUs 2Y, 2M, 2C and 2K, are taken out from image forming unit 1 and as shown in
Further, on the main body side of the image forming apparatus, first stay 31 and second stay 32 for supporting EPUs 2Y, 2M, 2C and 2K are installed. Furthermore, on the main body side of the image forming apparatus, when necessary, rail 33 which is a guide member for guiding grounding section 27 of support legs 24 at time of inserting or removing EPUs 2Y, 2M, 2C and 2K is installed.
Into first slit 22a formed in housing 22 of EPUs 2Y, 2M, 2C and 2K, first stay 31 is inserted and into second slit 22b formed in housing 22, second stay 32 is inserted. Therefore, when EPUs 2Y, 2M, 2C and 2K are mounted in image forming unit 1 of the image forming apparatus, the weight of housing 22 is not applied to support legs 24 and support legs 24 can swing in the direction of arrow p.
Rail 33, when inserting or removing EPUs 2Y, 2M, 2C and 2K from image forming unit 1, is used to smoothly avoid laser exposure device 50 installed on the path of support legs 24. Namely, as shown in
Next, rail 33 in EPU 2M will be described in detail. As shown in
Right rear grounding section 27a and right front grounding section 27b of housing 22 can be fit into slit 34 of rail 33. Slit 34, in opposite area 34a to laser exposure device 50, is formed along the top of laser exposure device 50 and in rear area 34b after passing laser exposure device 50, is equipped with a level difference for inverting the inclination direction of support legs 24.
Further, in EPUs 2C and 2K, rail 33 having slit 34, to guide grounding section 27 of right and left support legs 24, is installed on the right and left of housing 22. Further, as shown in
Next, the operation of the invention will be described. In EPUs 2Y, 2M, 2C and 2K mounted in image forming unit 1, housing 22 is supported by first and second stays 31 and 32, so that if no interference mechanism exists under support legs 24, the weight of housing 22 is not applied originally to support legs 24. Namely, support legs 24 can swing in the direction of arrow p shown in
For example, in EPU 2M, left support leg 24 shown in
When the image forming operation is started and image information is input from a scanner or a personal computer terminal, photosensitive drums 11Y, 11M, 11C and 11K of EPUs 2Y, 2M, 2C and 2K are rotated in the direction of arrow m and the image forming step is sequentially executed. In EPU 2Y of yellow (Y), the surface of photosensitive drum 11Y is uniformly charged by charger 14Y and then is irradiated with a laser beam corresponding to the yellow (Y) image information from laser exposure device 50, and an electrostatic latent image is formed. Furthermore, photosensitive drum 11Y forms a toner image by developing device 13Y, makes contact with intermediate transfer belt 10 rotating in the direction of arrow r, and primarily transfers the toner image onto intermediate transfer belt 10 by primary transfer roller 21Y.
Similarly to the yellow (Y) toner image forming process, the toner image forming process of magenta (M), cyan (C) and black (K) is performed. The toner images formed on photosensitive drums 11M, 11C and 11K are sequentially transferred to the position on intermediate transfer belt where the yellow (Y) toner image is formed and a full-color toner image is formed on intermediate transfer belt 10. Hereafter, the full-color toner image on intermediate transfer belt 10 reaches the position of secondary transfer roller 17 and is secondarily transferred onto sheet of paper P in a batch.
Hereafter, sheet of paper P passes the fixing step and the toner image is completed. Intermediate transfer belt 10, after end of the secondary transfer, is cleaned residual toner by belt cleaner 10b. Further, photosensitive drums 11Y, 11M, 11C and 11K, after primarily transferring the toner images to intermediate transfer belt 10, are removed residual toner by photoconductor cleaners 12Y, 12M, 12C and 12K and wait for the next image forming process.
During execution of this image forming process, when EPUs 2Y, 2M, 2C and 2K require maintenance, any of EPUs 2Y, 2M, 2C and 2K requiring maintenance is pulled out from image forming unit 1. For example, when EPU 2M is supported by first and second stays 31 and 32, EPU 2M is pulled out from the mounting position in image forming unit 1 shown in
On the other hand, right rear support leg 24a of EPU 2M shown in
Hereafter, support leg 24 is inclined as shown in
Next, when EPU 2M is pulled out outside the main body of the image forming apparatus and is raised as shown in
At this time, between bottom 22c of housing 22 and workbench 30, a gap [∂] is formed. Gap [∂] is wider than thickness [μ] of auto-toner sensor 23 projected from bottom 22c of housing 22, so that auto-toner sensor 23 can be prevented from touching workbench 30. Hereafter, on workbench 30, the maintenance necessary for EPU 2M is executed and after end of the maintenance, EPU 2M is mounted again on image forming unit 1.
When EPU 2M is raised from workbench 30 to mount EPU 2M on image forming unit 1, as shown in
Left support leg 24 of EPU 2M shown in
Next, grounding section 27a of right rear support leg 24a of EPU 2M shown in
Hereafter, EPU 2M further slides in the direction of arrow t and reaches the position shown in
Further, support leg 24, by the following operation, is removed from casing 22 or attached to casing 22. EPUs 2Y, 2M, 2C and 2K are taken out outside the image forming apparatus, and then as shown in
According to this embodiment, support leg 24 for casing 22 can swing in image forming unit 1, so that even if laser exposure device 50 disturbs the path of support leg 24 when inserting or removing EPUs 2Y, 2M, 2C and 2K from image forming unit 1, support leg 24 inclines and can avoid easily laser exposure device 50. Therefore, there is no need to widen the space for inserting support leg 24 around EPUs 2Y, 2M, 2C and 2K in image forming unit 1, thus the space can be reduced. Moreover, by installation of rail 33, support leg 24 can avoid smoothly laser exposure device 50. Furthermore, the level difference is formed in rear area 34b of slit 34 of rail 33 and the inclination of support leg 24 is inverted, so that support leg 24 can avoid more smoothly laser exposure device 50.
Further, the mounting of EPUs 2Y, 2M, 2C and 2K is detected by mounting detection switch 36, so that certainty of insertion and removal of EPUs 2Y, 2M, 2C and 2K can be obtained.
Furthermore, when putting EPUs 2Y, 2M, 2C and 2K on workbench 30 outside the main body of the image forming apparatus, support leg 24 is fixed to casing 22, thus although the space for support leg 24 when inserting or removing EPUs 2Y, 2M, 2C and 2K is reduced, gap [∂] between bottom 22a of casing 22 and workbench 30 can be reserved. Therefore, auto-toner sensor 23 can be prevented from damage due to touching workbench 30 or tools.
Further, the present invention is not limited to the embodiment aforementioned and within the scope of the present invention, can be modified variously. For example, the EPUs may have at least an image carrying member or at least a developing member. Further, the gap width between the bottom of the case member and the loading face when the case member is put on the loading face outside the main body of the image forming apparatus is not restricted.
Further, the detecting method of the detection member for detecting sure mounting of the case member on the main body of the image forming apparatus is optional such as mechanical or optical, and the installation position of the detection member is not restricted, and it is possible to install the detection member on the EPU side instead of the side of the main body of the image forming apparatus and when the EPUs are surely mounted on the main body of the image forming apparatus, to allow it to make contact with the rear frame and switch. Furthermore, the number of leg members attached to the case member and attaching position are not restricted. For example, when inserting or removing the EPUs, it is possible to install only the leg member of the part requiring to avoid a downward structural body so as to swing and install fixed legs for the parts requiring no avoidance.
As described above in detail, according to the present invention, the leg member of the case member can swing, so that when inserting or removing the EPUs from the main body of the image forming apparatus, the space for inserting the leg member can be reduced and the space around the EPUs can be reduced. Further, when putting the EPUs outside the main body of the image forming apparatus, the leg member can be fixed easily, and a necessary gap can be reserved between the bottom of the case member and the loading face, and the structural body on the bottom of the case member can be protected.