Patent Grant
8213834
The present application claims priority under 35 U.S.C §119 to Japanese Patent Application No. 2009-047265 filed Feb. 27, 2009, the entire contents of which are hereby incorporated herein by reference.
1. Field of the Invention
The present invention generally relates to a photoconductive drum to be used in an electrophotographic image forming apparatus such as a copier, a printer, and a facsimile machine and an image forming apparatus having the photoconductive drum.
2. Description of the Related Art
A photoconductive drum having a cylindrical shape in an electrophotographic image forming apparatus is required to be replaced periodically because the surface of the photoconductive drum may be worn out and the electrical characteristics of the surface may be deteriorated in accordance with the number of printed pages and the like. Some types of photoconductive drums have a photoconductive sleeve member and a wheel member, the photoconductive sleeve member having a cylindrical shape and having an outer circumference surface on which a photoconductive layer is formed, the wheel member being provided for establishing the connection between the photoconductive sleeve member and the driving shaft of the main body of the image forming apparatus. There are generally two methods of replacing the photoconductive drum having the photoconductive sleeve member and the wheel member. One is to replace the entire photoconductive drum with the photoconductive sleeve member and the wheel member. The other method is to separate the photoconductive sleeve member from the wheel member with each other and replace the photoconductive sleeve member only so that the wheel member can be repeatedly used (reused). In comparison between those two method, the method of replacing the photoconductive sleeve member only may have some advantages including that a fewer number of parts may be required to be replaced in replacing the photoconductive drum and that the running cost of the image forming apparatus may be more reduced. Because of the advantages, from the viewpoint of the cost, the method of replacing the photoconductive sleeve member only has been more widely used as the method of replacing the photoconductive drum especially in the image forming apparatuses in which the printing speed is relatively high and a relatively large number of pages are to be printed during the service life. This is because the frequency of replacing the photoconductive drum is higher in such image forming apparatus.
However, in a case where the method of replacing the photoconductive sleeve member only is adopted, if an operator touches the surface of the used photoconductive sleeve member, the hand of the operator may be stained due to dirt on the surface. Furthermore, if the operator touches the surface of a new photoconductive sleeve member to be used, the stain on the hand of the operator may be adhered to the surface of the photoconductive sleeve member and/or the surface of the photoconductive sleeve member may be damaged, thereby degrading the image quality. Therefore, it is required to pay particular attention so as not to touch the surface of the photoconductive sleeve member during the replacement.
Because of the restriction that the operator cannot touch the surface of the photoconductive sleeve member, in the apparatus in which only the photoconductive sleeve member is to be replaced, it may take longer to complete the replacement of the photoconductive drum, thereby increasing the repair and maintenance cost. Some efforts have been made to overcome the problem.
For example, Japanese Patent Application Publication No. H02(1990)-502130 describes an image forming apparatus in which only the photoconductive sleeve member can be replaced without any necessity of touching the surface of the photoconductive sleeve member.
Further,
As shown in
One end side of the cylindrical-shaped photoconductive sleeve member 1 is engaged with the outer circumference of the cap member 2 which is fixed to a small diameter part 4b of the driving shaft 4. On the other hand, the other end side of the cylindrical-shaped photoconductive sleeve member 1 is engaged with outer circumference of the wheel member 3 fixed to a stepping part 4c formed between the small diameter part 4b and a large diameter part 4a of the driving shaft 4. Further, by screwing the handle 5 into the end portion of the small diameter part 4b of the driving shaft 4, the photoconductive sleeve member 1 is sandwiched between a cap flange section 2f of the cap member 2 and a wheel flange section 3f of the wheel member 3. As a result, the photoconductive sleeve member 1 is fixed in position with respect to the driving shaft 4. Further, the wheel member 3 serves as a guide member capable of guiding the photoconductive sleeve member 1 when the photoconductive sleeve member 1 is attached to and detached from the main body of the image forming apparatus. To that end, the wheel member 3 includes plural ribs 30 extending along the inner circumferential surface of the photoconductive sleeve member 1.
Further, in the photoconductive sleeve member 1, there is provided a deformation prevention member 7 contacting plural portions arranged in the circumferential direction on the inner circumferential surface of the photoconductive sleeve member 1. As shown in
Further, the prevention piece 71 includes an engagement core 71a provided where the first prevention piece 71 and the second prevention piece 72 are pressed by the strut spring 73, so that the engagement core 71a can be entered into (moved through) an engage hole formed in the second prevention piece 72. Further, the strut spring 73 is disposed inside the engagement core 71a. Further, the second prevention piece 72 includes a fixing screw 72a to fix the position of the engagement core 71a. Therefore, by tightening the fixing screw 72a, it becomes possible to fix the position of the engagement core 71a with respect to the second prevention piece 72. By doing this, the positional relationship between the first prevention piece 71 and the second prevention piece 72 can be fixed (determined) regardless of the pressing force (status) of the strut spring 73. In this configuration, while the strut spring 73 is being compressed, by tightening the fixing screw 72a, the first prevention piece 71 and the second prevention piece 72 can no longer press the inner circumferential surface of the photoconductive sleeve member 1. In this situation, it becomes possible to remove the deformation prevention member 7 from inside the photoconductive sleeve member 1.
Next, a procedure of removing the photoconductive sleeve member 1 of the photoconductive drum 100 from the image forming apparatus and replacing the photoconductive sleeve member 1 is described.
To replace the photoconductive sleeve member 1, as shown in
Then, the deformation prevention member 7 is removed from the inside of the photoconductive sleeve member 1. Next, a new photoconductive sleeve member 1 is attached to the deformation prevention member 7. Then, by fixing the photoconductive sleeve member 1 with the deformation prevention member 7 to the driving shaft 4 in the procedure opposite to that of removing the photoconductive sleeve member 1 described above, the replacement of the photoconductive sleeve member 1 can be completed.
In the above method, it is true that only the photoconductive sleeve member 1 may be replaced and the deformation prevention member 7 as the handle member may be reused. However, the operation of removing the handle member disposed in the photoconductive sleeve member 1 may be so difficult that it may increase time to complete the replacement of the photoconductive sleeve member 1.
On the other hand, there may be another method in which an operator can grasp the handle member disposed in the photoconductive sleeve member to replace the photoconductive sleeve member so that the entire photoconductive sleeve member including handle member may be replaced (i.e., the handle member cannot be reused). However, from the viewpoint of saving resources, discarding the handle member in this method is a waste of resources.
Japanese Patent Application Publication No. 2008-203425 discloses a configuration including an engagement unit capable of switching between an engagement state and a non-engagement state based on the operation of an operation member. In the engagement state, an end surface member corresponding to the cap member 2 of the photoconductive drum 100 shown in
By having this configuration, the end surface member engaged with the photoconductive sleeve member and integrally removed from the driving shaft may serve as a handle member; therefore, the operator doesn't have to place a hand inside the photoconductive sleeve member to remove the handle member from the photoconductive sleeve member. As a result, it becomes possible to easily separate the handle member from the photoconductive sleeve member, and it may not increase time to complete the replacement of the photoconductive sleeve member. Further, the end surface member serving as the handle member may be reused by being engaged with a new photoconductive sleeve member. Therefore, it is not necessary to discard the end surface member, which is useful from the viewpoint of saving resources.
Further, according to the configuration described in Japanese Patent Application Publication No. 2008-203425, one end surface member engaged with the photoconductive sleeve member can be integrally removed from the other end surface member and the driving shaft. However, as an alternative configuration, two end surface members and the photoconductive sleeve member may be removed from the driving shaft. Then, one end surface member and the photoconductive sleeve member may be integrally removed from the other end surface member. In this configuration, for example, while a hand or a tool is used to serve as the separated driving shaft to fix the position of the other end surface member, by removing the end surface member from the other end surface member, it becomes possible to integrally remove the end surface member and the photoconductive sleeve member from the other end surface member.
However, in the configuration described in Japanese Patent Application Publication No. 2008-203425, the one end surface member is engaged with the photoconductive sleeve member based on a friction force exerted between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface. Therefore, a retention force retaining the position of the photoconductive sleeve member with respect to the one end surface member by the sleeve inner circumferential surface pressing member is constant. Therefore, because of such a strong engagement between the photoconductive sleeve member and the other end surface member, when an operator integrally removes the one end surface member and the photoconductive sleeve member from the other end surface member, more force than is supposed by the design engineer may be temporarily applied to the contacting section between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface. In this case, if the applied force exceeds the maximum static friction force between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface, the engagement between the one end surface member and the photoconductive sleeve member may be destroyed (released). When the engagement is destroyed, the engagement between the photoconductive sleeve member and the other end surface member may not be released, thereby preventing the replacement of the photoconductive sleeve member only. Further, when, for example, an operator holds the other end surface member, and if the engagement is destroyed, the photoconductive sleeve member may be dropped off and the operator may be injured.
To avoid the problems, a new configuration may be adopted in which a biasing member such as a spring member having a higher biasing force is provided to increase the pressing force of the sleeve inner circumferential surface pressing member with respect to the sleeve inner circumferential surface. However, in a case where this method is adopted to increase the biasing force of the biasing member, while the end surface member is in contact with the photoconductive sleeve member, the higher pressing force is always applied to the contacting section between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface including when such higher pressing force is not required. Because of this feature, it may become necessary to reinforce the members so as not to be deformed even when the higher pressing force is applied to the contacting section between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface, thereby increasing the manufacturing costs.
The present invention is made in light of the above problems and may provide a photoconductive drum where the end surface member is engaged with the photoconductive sleeve member, and the photoconductive drum is capable of not generating a higher pressing force when it is not necessary to apply the higher pressing force to the contacting section between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface. Further, the photoconductive drum is capable of maintaining the engagement between the end surface member and the photoconductive sleeve member even when a high force is temporarily applied to the contacting section between the sleeve inner circumferential surface pressing member and the sleeve inner circumferential surface. Further, the present invention may provide an image forming apparatus having the above photoconductive drum.
According to an aspect of the present invention, there is provided a photoconductive drum including:
a photoconductive sleeve member 1 having a hollow cylindrical shape and having a photoconductive outer circumferential surface;
a first end surface member 2 configured to be engaged with one end of the photoconductive sleeve member 1 in a center line direction of the photoconductive sleeve member 1;
a second end surface member 3 configured to be engaged with the other end of the photoconductive sleeve member 1 in the center line direction of the photoconductive sleeve member 1;
a contacting unit disposed in the first end surface member 2 and including an operation member 6, the contacting unit being configured to be operated to select between a contacting mode and a non-contacting mode due to an operation of the operation member 6, the contacting mode indicating that the first end surface member 2 is engaged with the photoconductive sleeve member 1, the non-contacting mode indicating that the engagement is released between the first end surface member 2 and the photoconductive sleeve member 1; and
a sleeve inner circumferential surface pressing member 11 disposed in the contacting member and configured to be operated due to the operation of the of the operation member 6 to select between a state where the sleeve inner circumferential surface pressing member 11 is in contact with and presses an inner circumferential surface of the photoconductive sleeve member 1 so that the first end surface member 2 is engaged with the photoconductive sleeve member 1 and a state where the sleeve inner circumferential surface pressing member 11 is not in contact with and presses the inner circumferential surface of the photoconductive sleeve member 1 so that the engagement is released between the first end surface member 2 and the photoconductive sleeve member 1, wherein
the photoconductive drum includes a mechanism where, when the sleeve inner circumferential surface pressing member 11 is in contact with the inner circumferential surface of the photoconductive sleeve member 1, a displacement of a position of the first end surface member 2 with respect to the photoconductive sleeve member 1 in the center line direction leads to increase a pressing force applied from the sleeve inner circumferential surface pressing member 11 to the inner circumferential surface of the photoconductive sleeve member 1.
According to an embodiment of the present invention, even when a force is applied exceeding the maximum static friction force generated between the arm member 11 and the inner circumferential surface of the photoconductive sleeve member 1 upon the cap member 2 being engaged with the photoconductive sleeve member 1 due to the operation of the operation member 6 and the position of the cap member 2 with respect to the photoconductive sleeve member 1 is displaced outward in the center line direction, the displacement of the cap member 2 leads to increase the pressing force applied from the arm member 11 to the inner circumferential surface of the photoconductive sleeve member 1. Because of this feature, the larger the displacement becomes, the larger is the pressing force is applied to the contacting sections 112a and 112b where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1. As a result, the engagement may be reinforced between the cap member 2 and the photoconductive sleeve member 1. Because of this feature, even when an extraordinary force is temporarily applied to the contacting sections 112a and 112b, the engagement may be maintained between the cap member 2 and the photoconductive sleeve member 1. On the other hand, as long as the position of the cap member 2 with respect to the photoconductive sleeve member 1 is not displaced outward in the center line direction, the pressing force applied to the contacting sections 112a and 112b where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1 is equal to the pressing force applied when the cap member 2 is engaged with the photoconductive sleeve member 1 due to the operation of the operation member 6. Because of this feature, when the cap member 2 is engaged with the photoconductive sleeve member 1 and if no extraordinary pressing force is required to be applied to the contacting sections 112a and 112b where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, such extraordinary pressing force may not be applied to the contacting sections.
Therefore, in the photoconductive drum 100 according to this embodiment of the present invention, when the cap member 2 is engaged with the photoconductive sleeve member 1 and no extraordinary pressing force is required to be applied to the contacting sections where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, it may become possible to avoid the application of such extraordinary pressing force to the contacting sections. Further, even when an extraordinary pressing force is temporarily applied to the contacting sections 112a and 112b, the engagement may be maintained between the cap member 2 and the photoconductive sleeve member 1.
Other objects, features, and advantages of the present invention will become more apparent from the following description when read in conjunction with the accompanying drawings, in which:
In the following, embodiments of the present invention applied to a printer (hereinafter referred to as a printer 200) as an image forming apparatus will be described with reference to the accompanying drawings.
After charges are uniformly distributed on the surface of the photoconductive drum 100 by the charging device 19, a laser light L in accordance with image data to be printed is irradiated onto the surface of the photoconductive drum 100 by the exposure device 20. By doing this, a static latent image is formed on the surface of the photoconductive drum 100. Then, the static latent image is developed by the development device 21 so that a toner image is formed on the surface of the photoconductive drum 100.
As shown in
On the other hand, when a continuous paper having the holding lines is used as the continuous web P, the continuous paper is accommodated into a Z-shape in an accommodation section 75 disposed inside the printer 200. Then, the top of the continuous paper is sandwiched between the pair of the resist rollers of the resist device 24.
The pair of the resist rollers of the resist device 24 is driven to feed the continuous web P so that a predetermined position of the continuous web P is fed to the position where the toner image formed on the photoconductive drum 100 faces the transfer section 40. The continuous web P may be used for the applications of printing direct mail, invoices, manuals, books and the like. Further, as the applications have expanded, more and more types of papers ranging, for example, from thin paper to thick paper and from high-quality paper to coarse paper have been used as the continuous web. Furthermore, the length in the width direction (i.e., in the front-rear direction in
In the transfer section 40, the toner image formed on the surface of the photoconductive drum 100 is transferred to the surface of the continuous web P by the corona transfer device 43. Then, the continuous web P having passed through the transfer section 40 is further fed toward a fixing section 50 by a web feeding device 25.
While the continuous web P fed toward the fixing section 50 passes through a preheating section 26, the toner image transferred to the surface of the continuous web P is heated to the temperature at about the transfer temperature of the toner resin. Then, the continuous web P is further fed to the fixing section 50 including a heat roller 27 having a heater and a backup roller 28. In the fixing section 50, the toner image on the continuous web P is heated and pressed between the heat roller 27 and the backup roller 28 to be melted and adhered to the surface of the continuous web P, thereby fixing the toner image on the continuous web P. The continuous web P having the fixed toner image on the continuous web P is stored in a stack section 90.
Further, in double-sided printing, in the first step, a toner image is transferred and fixed to the front surface (first surface) P1 of the continuous web P as the first printing using the printer 200 described above. Then, in the second step, the continuous web P stored in the stack section 90 is taken out to be set in a manner such that the surface opposite to the surface on which the toner image is transferred and fixed in the first printing becomes the surface on which another toner image is to be transferred and fixed in the second printing. Then, in the second printing, the another toner image is transferred and fixed to the rear surface (second surface) P2 of the continuous web P.
Next, an exemplary configuration of the photoconductive drum 100 applicable to the printer 200 according to an embodiment of the present invention is described with reference to the accompanying drawings.
As shown in
First, a procedure is described to take out the photoconductive drum 100 from the printer 200.
In
Next, as shown in
Further, according to the embodiment of the present invention, the photoconductive drum 100 has a cylindrical shape; and the cap member 2 includes two operation members 6 symmetrically disposed as shown in
In the photoconductive drum 100 according to the embodiment of the present invention, when the photoconductive drum 100 is in its normal position, right and left portions of the photoconductive drum 100 about the center line are symmetrically disposed. However, since the shape of the first arm members 11a differs from that of the second arm members 11b, top and bottom portions of the photoconductive drum 100 about the center line are not symmetrically disposed.
Further,
When it is assumed that a cross-sectional view of a member having a cylindrical or conical shape when cut along a virtual plane including a line parallel to the center line of the member shows only the part of member displaced on the virtual plane, the cross-sectional views differ depending on the position of the virtual planes. For example, as far as the side cross-sectional view is concerned, a case is considered where there is provided the side cross-sectional view when cut along the virtual (vertical) plane including the line h-h′ in
Next, a procedure to replace the photoconductive sleeve member 1 is described.
Before the photoconductive drum 100 is removed from the printer 200, the photoconductive drum 100 is in the status as shown in
When the operation lever sections 6b of the operation members 6 in the cap member 2 are pulled outward in the center line direction as described above, the operation lever sections 6b rotate in the arrow direction J in
Further, at the same time when the operation members 6 are operated as described above, eccentric cam sections 6a of the operation members 6 are also rotated. Due to the rotation of the eccentric cam sections 6a, flange sections 3c on the cap member side of the wheel member 3 are pressed inward in the center line direction (i.e., in the direction opposite to the arrow direction Q in
Next, the operation members 6 are rotated in the direction opposite to the arrow direction J in
Then, the used photoconductive sleeve member 1 is replaced by a new photoconductive sleeve member 1. The new photoconductive sleeve member 1 is retained in position between the cap member 2 and the wheel member 3 by performing the procedure opposite to that for removing the photoconductive sleeve member 1 as described above to form a new photoconductive drum 100. The new photoconductive drum 100 is attached to the driving shaft 4 and the front cover 210 is closed, so that the replacement operation of the photoconductive sleeve member 1 is completed. By doing as described above, it may become possible to replace the photoconductive sleeve member 1 without touching the surface of the photoconductive sleeve member 1 with a hand or tool.
According to the embodiment of the present invention, the photoconductive drum 100 can be attached to the driving shaft 4 in the state where the cap member 2 and the wheel member 3 are engaged with the photoconductive sleeve member 1 and where the engagement between the arm members 11 and the photoconductive sleeve member 1 is released. The driving shaft 4 is the driving axis for driving the photoconductive body of the printer 200.
Next, the details of the photoconductive drum 100 according to the embodiment of the present invention are described.
As shown in
To integrate the cap member 2 with the photoconductive sleeve member 1, first, the outer circumferential surface of a cap-member outer circumferential section 2a of the cap member 2 is engaged with one end section of the inner circumferential surface of the photoconductive sleeve member 1 in the center line direction. Next, the operation members 6 are operated (rotated in the arrow direction J in
In this case, the cap member 2 and the wheel member 3 are engaged with each other in a manner such that the inner circumferential surface of the cap-member inner circumferential section 2b of the cap member 2 is in contact with the outer circumferential surface of the cap-member-side end section 3d of the wheel member 3.
Further, as shown in
When the photoconductive drum 100 is to be attached to the main body of the printer 200, as shown in
Further, as described above, the driving shaft 4 is supported with respect to the main body of the printer 200 by shaft bearings (not shown) provided on both end sides of the driving shaft 4 in the center line direction.
Further, when the photoconductive drum 100 is being fixed in position with respect to the driving shaft 4, as shown in
Next, more details are described how the arm members 11 are in contact with and press the inner circumferential surface of the photoconductive sleeve member 1 when the operation members 6 are operated.
The arm member 11 includes the first arm member 11a and the second arm member 11b. As shown in
Further, as shown in
As shown in
Further, as shown in
Further, as shown in
As shown in
This pushing structure is described in more detail with reference to
Further, as shown in
Next, to replace the photoconductive sleeve member 1, first, the lock member is released so that the operation members 6 can be moved (rotated). Then, the operation members 6 are pulled in the arrow direction Q in
In a case where the cap member 2 is pulled in the arrow direction N in
On the other hand, when the cap member 2 is pulled in the arrow direction N in
In this case, when the ends of the arm members 11 on the side of the arm reinforcement shafts 110 are in contact with the photoconductive sleeve member 1 at contacting sections 112 (112a and 112b in
As described above, when the arm members 11 are pulled in the arrow direction N at the positions in the arm elongated holes 12 and are rotated about the arm reinforcement shafts 110, the hinge member 14 moves in the arrow direction N in a manner such that the moving distance of the hinge member 14 in the center line direction is longer than the moving distance of the cap member 2 in the center line distance. As described above, when the hinge member 14 moves in the arrow direction N, the hinge member 14 approaches the shafts 13 (“moving distance of shaft 13″=”moving distance of cap member 2″<“moving distance of hinge member 14”). Because of this feature, the force caused by the movement of the hinge member 14 is applied so that the shafts 13 within the arm elongated holes 12 slide to the side of (approach) the hinge member 14, thereby rotating the two arm members 11 to open the angle between longitudinal directions of the arm members 11 (hereinafter may be simplified as open the arm members 11).
By having the configuration as described above, the larger the moving distance (displacement) of the cap member 2 with respect to the photoconductive sleeve member 1 in the center line direction becomes, the larger is the pressing force applied to the contacting sections 112 between the arm members 11 and the inner circumferential surface of the photoconductive sleeve member 1, thereby reinforcing the engagement between the cap member 2 and the photoconductive sleeve member 1. Because of this feature, even when a large pressing force is temporarily applied to the contacting section 112, the engagement can be maintained between the cap member 2 and the photoconductive sleeve member 1. Further, as long as the position of the cap member 2 with respect to the photoconductive sleeve member 1 is not displaced outward in the center line direction, the pressing force applied to the contacting sections 112 is unchanged, and is based on the pressing force due to the biasing force of the spring members 15. Because of this feature, a large pressing force may not be applied when no such large pressing force is required to the contacting sections 112 where the cap member 2 is engaged with the photoconductive sleeve member 1.
As shown in
As described above, when the position of the cap member 2 with respect to the photoconductive sleeve member 1 is displaced in the arrow direction N in
The longitudinal direction of the arm elongated holes 12 with respect to the center line direction defines the magnitude of the force to be applied to open the arm members 11. When the longitudinal directions of the arm elongated holes 12 are as shown in
Further, as shown in
As described above, when the cap member 2 is pulled in the arrow direction N in
In other words, when the cap member 2 is pulled in the arrow direction N in
By having the configuration as described above, the photoconductive sleeve member 1 and the cap member 2 may be engaged with each other more strongly. Therefore, it may become possible to ensure integrally removing the photoconductive sleeve member 1 and the cap member 2 from the wheel member 3.
In the photoconductive drum 100 according to this embodiment of the present invention, in the configuration of the engagement between the photoconductive sleeve member 1 and the cap member 2, the arm members 11 are provided to be rotated relative to each other (opened and closed) to act as wedges to be secured to the inner circumferential surface of the photoconductive sleeve member 1. By having this feature, when, for example, an operator holds the cap member 2 to replace the photoconductive sleeve member 1 and the photoconductive sleeve member 1 is about to be dropped off, a retention force may be increased so as to prevent the dropping of the photoconductive sleeve member 1. Because of this feature, when compared with a conventional photoconductive drum 100, it may become possible to reinforce the engagement between the cap member 2 and the photoconductive sleeve member 1, thereby enabling preventing, for example, damage of the photoconductive sleeve member 1 caused by being dropped off during the replacement.
On the other hand, as shown in
In the description of this embodiment of the present invention, a case is described where the continuous web P is used as a recording medium to be printed in the printer 200 as an image forming apparatus using the photoconductive drum 100 having the features of the present invention. However, the present invention is not limited to this configuration using the continuous web. For example, any cut sheets such as A4 and B4 sized sheets may alternatively be used in the image forming apparatus according to an embodiment of the present invention.
Further, in this embodiment of the present invention, a case is described where, in the photoconductive drum 100 having the features of the present invention, the arm member 11 is provided serving as a sleeve inner circumferential surface pressing member having the function in which, when the positional displacement of the cap member 2 is generated with respect to the photoconductive sleeve member 1 outward in the center line direction while the sleeve inner circumferential surface pressing member is in contact with the inner circumferential surface of the photoconductive sleeve member 1, the positional displacement leads to increasing the pressing force of the sleeve inner circumferential surface pressing member to press the inner circumferential surface of the photoconductive sleeve member 1. However, the present invention is not limited to this configuration using the arm member 11 as the sleeve inner circumferential surface pressing member. Namely, any other element serving as the sleeve inner circumferential surface pressing member may be alternatively used as long as the element has the function of, when the positional displacement of the cap member 2 (more generally, a first end surface member) is generated with respect to the photoconductive sleeve member outward in the center line direction while the sleeve inner circumferential surface pressing member is in contact with the inner circumferential surface of the photoconductive sleeve member 1, the positional displacement is used (leads) to increase the pressing force of the sleeve inner circumferential surface pressing member to press the inner circumferential surface of the photoconductive sleeve member.
According to this embodiment of the present invention, the photoconductive drum 100 includes the photoconductive sleeve member 1, the cap member 2, the wheel member 3, and a contacting unit. The photoconductive sleeve member 1 having a hollow cylindrical shape has a photoconductive outer circumferential surface. The cap member 2 serves as the first end surface member engaging one end of the photoconductive sleeve member 1 in the center line direction of the photoconductive sleeve member 1. The wheel member 3 serves as the second end surface member engaging the other end of the photoconductive sleeve member 1 in the center line direction. The contacting unit is disposed in the cap member 2 and includes the operation member 6 to be operated to select between a contacting mode and a non-contacting mode. In the contacting mode, the cap member 2 is engaged with the photoconductive sleeve member 1. On the other hand, in the non-contacting mode, the engagement is released between the cap member 2 and the photoconductive sleeve member 1. To engage the cap member 2 with the photoconductive sleeve member 1, the contacting unit in the cap member 2 further includes the arm member 11 serving as the sleeve inner circumferential surface pressing member to be operated to select between the state where the sleeve inner circumferential surface pressing member is in contact with and pressing the inner circumferential surface of the photoconductive sleeve member 1 and the state where the sleeve inner circumferential surface pressing member is not in contact with the inner circumferential surface of the photoconductive sleeve member 1. Further, in the state where the sleeve inner circumferential surface pressing member is not in contact with the inner circumferential surface of the photoconductive sleeve member 1, the engagement is released between the cap member 2 and the photoconductive sleeve member 1. In the state where the engagement is released, the operation member 6 can be operated so that the arm member 11 is in contact with and presses the inner circumferential surface of the photoconductive sleeve member 1. By doing this, the cap member 2 is engaged with the photoconductive sleeve member 1. The photoconductive drum 100 according to this embodiment of the present invention having the features as described above includes the mechanism as described above. Namely, in the mechanism, after the arm member 11 is in contact with the inner circumferential surface of the photoconductive sleeve member 1 and when the position of the cap member 2 with respect to the photoconductive sleeve member 1 is displaced outward in the center line direction, the displacement of the cap member 2 leads to increasing the pressing force applied from the arm member 11 to the inner circumferential surface of the photoconductive sleeve member 1. By having this mechanism, if a force is applied exceeding the maximum static friction force generated between the arm member 11 and the inner circumferential surface of the photoconductive sleeve member 1 upon the cap member 2 being engaged with the photoconductive sleeve member 1 due to the operation of the operation member 6 and even when the position of the cap member 2 with respect to the photoconductive sleeve member 1 displaces outward in the center line direction, the displacement of the cap member 2 leads to increasing the pressing force applied from the arm member 11 to the inner circumferential surface of the photoconductive sleeve member 1. Because of this feature, the larger the displacement is, the larger is the pressing force applied to the contacting sections 112a and 112b where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1. As a result, the engagement may be reinforced between the cap member 2 and the photoconductive sleeve member 1. Because of this feature, even when an extraordinary force is temporarily applied to the contacting sections 112a and 112b, the engagement may be maintained between the cap member 2 and the photoconductive sleeve member 1. On the other hand, as long as the position of the cap member 2 with respect to the photoconductive sleeve member 1 is not displaced outward in the center line direction, the pressing force applied to the contacting sections 112a and 112b where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1 is equal to the force applied when the cap member 2 is engaged with the photoconductive sleeve member 1 due to the operation of the operation member 6. Because of this feature, when the cap member 2 is engaged with the photoconductive sleeve member 1 and if no extraordinary pressing force is required to be applied to the contacting sections 112a and 112b where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, such extraordinary pressing force may not be generated to be applied to the contacting sections. Therefore, in the photoconductive drum 100 according to this embodiment of the present invention, when the cap member 2 is engaged with the photoconductive sleeve member 1 and no extraordinary pressing force is required to be applied to the contacting sections where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, it may become possible to avoid the generation of such extraordinary pressing force to be applied to the contacting sections. Further, even when an extraordinary pressing force is temporarily applied to the contacting sections 112a and 112b, the engagement may be maintained between the cap member 2 and the photoconductive sleeve member 1.
Further, as described above, the contacting unit of the photoconductive drum 100 according to this embodiment of the present invention includes the arm members 11, the arm holder 10, the spring members 15, the hinge member 14 and the like.
Further, in the photoconductive drum 100 according to this embodiment of the present invention, as the sleeve inner circumferential surface pressing member, two arm members 11 are provided. The hinge member 14 pivotally supports the arm members 11 so that the arm members 11 (the first arm member 11a and the second arm member 11b) can be rotated with respect to each other. The arm members 11 are rotatably connected with respect to each other so that each of the arm members 11 rotates about the hinge center axis 14p which is a first virtual axis orthogonal to the center line of the photoconductive sleeve member 1. Further, the arm members 11 (the first arm member 11a and the second arm member 11b) are provided so that the arm members 11 can be in contact with the inner circumferential surface of the photoconductive sleeve member 1 and disposed opposite to each other with respect to a virtual plane including the hinge center axis 14p and the center line of the photoconductive sleeve member 1. In other words, each of the arm members 11 is disposed one on each of the opposite sides (i.e., the upper side and the lower side) with respect to the horizontal plane including the hinge center axis 14p. Further, in the state where the two arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, the cap-member-side virtual angle θ2 is less than 180 degrees. Herein, the cap-member-side virtual angle θ2 is one of two angles formed between two virtual lines L1 and L2 and is the angle formed on the side of the cap member 2. The lines L1 and L2 are parallel to the virtual lines extending between the contacting sections 112a and 112b, respectively, and the hinge center axis 14p. The hinge center axis 14p serves as a rotation axis of the rotation of the arm members 11 about the hinge member 14. Further, there are provided the spring member 15, the pushing section 6c of the operation member 6, and the protrusion section 17 of the first arm member 11a. The spring member 15 is the biasing member capable of applying a biasing force to the arm members 11 so as to increase the cap-member-side virtual angle θ2 between the arm members 11. The pushing section 6c of the operation member 6 serves as a biasing prevention unit to be operated against the biasing force to select the state where the arm members 11 are not in contact with the photoconductive sleeve member 1 by decreasing the cap-member-side virtual angle θ2 due to the operation of the operation member 6 to release the engagement between the cap member 2 and the photoconductive sleeve member 1. Further, in the state where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1 and when the biasing force generated by the spring members 15 is applied to the arm members 11 so as to increase the cap-member-side virtual angle θ2, the engagement between the cap member 2 and the photoconductive sleeve member 1 may be reinforced. Further, the cap member 2 includes the arm holder 10 serving as a to-be-held section for the arm members 11, the arm holder 10 holding the arm members 11 in the arm elongated holes 12. The arm holder 10 fixes the position of the arm elongated holes 12 with respect to the cap member 2 in the center line direction. Further, the arm holder 10 pivotally supports the arm members 11 so that the arm members 11 can be rotated with respect to the arm holder 10 about the respective center axes of the shafts 13, the center axes being parallel to the hinge center axis 14p.
In this configuration, the position of the to-be-held section of the shaft 13 in the arm elongated hole 12 is fixed in position with respect to the cap member 2 in the center line direction. Because of this feature, when the position of the cap member 2 with respect to the photoconductive sleeve member 1 in the center line direction is displaced, the arm members 11 at the to-be-held section are to be moved in the center line direction along with the cap member 2. However, the ends of the arm members 11 on the side of the arm reinforcement shafts 110 are in pressure-contact with the inner circumferential surface of the photoconductive sleeve member 1 so as to press the inner circumferential surface of the photoconductive sleeve member 1. Because of this contact, the movement of the ends of the arm members 11 on the side of the arm reinforcement shafts 110 in the center line direction is controlled due to the friction force generated between the arm members 11 and the inner circumferential surface of the photoconductive sleeve member 1. As described above, with respect to the arm members 11, the force to move the arm members 11 in the center line direction is applied to the to-be-held section; and, on the other hand, the other force to retain the position of the arm members 11 with respect to the photoconductive sleeve member 1 at the ends of the arm members 11 on the side of the arm reinforcement shafts 110. Due to the forces applied to the arm members 11 as described above, a moment is generated and applied to the arm members 11 tending to rotate the arm members 11 about an axis passing near the ends of the arm members 11 on the side of the arm reinforcement shafts 110 as the center of the rotation. In this state, the arm members 11 are rotatably supported with respect to the arm holder 10 at the to-be-held section of the arm holder 10. Further, the arm members 11 are rotatably supported by the hinge member 14 so as to be rotated with respect to each other. Because of this feature, due to the moment applied to the arm members 11, the arm members 11 rotate in a manner such that the ends of the arm members 11 on the side of the hinge member 14 move to the side of the cap member 2. Two arm members 11 (11a and 11b) are simultaneously rotated in the opposite directions about the respective axes near the ends of the arm members 11 on the side of the arm reinforcement shafts 110 as the centers of the rotations in a manner such that the ends of the arm members 11 on the side of the hinge member 14 move to the side of the cap member 2. Because of this movement (rotation), the force is applied to increase the cap-member-side virtual angle θ2, to open the arm members 11, thereby increasing the pressing force applied from the arm members 11 to the inner circumferential surface of the photoconductive sleeve member 1. By having this feature, it may become possible to have a mechanism in which, when the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, the displacement of the cap member 2 with respect to the photoconductive sleeve member 1 in the center line direction leads to increasing the pressing force applied from the arm members 11 to the inner circumferential surface of the photoconductive sleeve member 1.
Further, in the photoconductive drum 100 according to this embodiment of the present invention, the arm member 11 includes the arm elongated hole 12 formed between the position where the hinge member 14 is to be attached and the position where the arm reinforcement shaft 110 is to be attached. Then, the arm holder 10 pivotally supports the arm members 11 so that the arm members 11 can be rotated about the respective center axes (second virtual axes) of the shafts 13. The hinge member 14 having the hinge center axis 14p which is a first virtual axis can be moved with respect to the cap member 2 in the center line direction. That is, the position of the first virtual axis is different from that of the second virtual axis, the first virtual axis serving as the center of the rotation of the arm member 11 (e.g. the first arm member 11a) with respect to the other arm member 11 (e.g. the second arm member 11b), the second virtual axis serving as the center of the rotation of the arm members 11 with respect to the arm holder 10, and the position of the second virtual axis with respect to the cap member 2 being fixed.
However, there may be alternative configurations of the present invention. More specifically, even if the first virtual axis and the second virtual axis are the same, the above mechanism may also be provided where, as described above, there are two arm members capable of being in contact with the inner circumferential surface of the photoconductive sleeve member 1 and the displacement of the cap member 2 with respect to the photoconductive sleeve member 1 in the center line direction leads to increasing the pressing force applied from the arm members 11 to the inner circumferential surface of the photoconductive sleeve member 1.
As an example of the above case where the first virtual axis and the second virtual axis are the same, in the state where the arm members are in contact with the inner circumferential surface of the photoconductive sleeve member 1 in a manner such that the cap-member-side virtual angle θ2 is less than 180 degrees, the position of the hinge member 14 is fixed with respect to the cap member 2. In this configuration, the hinge center axis 14p of the hinge member 14 may serve as the first virtual axis and the second virtual axis at the same time.
More specifically, in this configuration, when the position of the cap member 2 with respect to the photoconductive sleeve member 1 is displaced, one force is applied to a portion where the arm member 11 is engaged with the hinge member 14 so that the hinge member is moved along the cap member 2 in the center direction and the other force is applied to the contacting sections where the arm members are in contact with the photoconductive sleeve member 1 so as to retain the position of the arm members 11 with respect to the photoconductive sleeve member 1, thereby generating a moment tending to rotate the arm members 11 about the respective axes near the ends of the arm members 11 on the side of the arm reinforcement shafts 110 as the centers of the rotations. In this case, the arm members 11 are rotatably supported by the hinge member 14 with respect to the cap member 2. Further, the arm members 11 are rotatably supported with respect to each other. Because of the feature, due to the moment, the two arm members 11 rotate in the directions opposite to each other about the respective axes near the ends of the arm members 11 on the side of the arm reinforcement shafts 110 as the centers of the rotations in a manner such that the hinge member 14 moves along with the cap member 2. Due to the rotations, a force is applied to the arm members 11 so as to increase the cap-member-side virtual angle θ2 to open the arm members 11. As a result, the pressing force applied from the arm members 11 to the inner circumferential surface of the photoconductive sleeve member 1 may be increased. Therefore, in this configuration, the displacement of the position of the cap member 2 with respect to the photoconductive sleeve member 1 in the center line direction may lead to increasing the pressing force applied from the arm members 11 to the inner circumferential surface of the photoconductive sleeve member 1.
Further, in the photoconductive drum 100 according to this embodiment of the present invention, the to-be-held section for the arm members 11 refers to a contact section between the arm elongated hole 12 and the shaft 13. The arm elongated hole 12 is formed on the arm members 11 and between the contacting section 112 where the arm member 11 is in contact with the inner circumferential surface of the photoconductive sleeve member 1 and the hinge member 14 pivotally supporting the arm members 11 so that the arm members 11 can be rotated with respect to each other. The arm members 11 are supported by the arm holder 10 in a manner such that the hinge member 14 with respect to the cap member 2 is slidably moved in the center direction. Further, in the state when the arm member 11 is in contact with the inner circumferential surface of the photoconductive sleeve member 1, the virtual angle θ1 is less than 180 degrees. The virtual angle θ1 is one of two angles formed between two virtual lines La and Lb and is the angle formed on the side opposite to the side of the cap member 2. The virtual lines La and Lb are parallel to the longitudinal directions of the respective arm elongated holes 12 of the arm members 11. By having this configuration, in the state where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, when the cap member 2 with respect to the photoconductive sleeve member 1 is displaced, the component forces are applied from the shaft 13 positioned between two arm members 11 to the arm elongated holes 12 formed in the arm members 11. The component forces are more likely to be applied so as to increase the cap-member-side virtual angle θ2 to open the arm members 11 due to the tilted direction of the elongated holes 12. Because of this feature, it may become possible to reinforce the pressing force applied from the arm members 11 to the inner circumferential surface of the photoconductive sleeve member 1, thereby reinforcing the engagement between the cap member 2 and the photoconductive sleeve member 1.
Further, one end of the spring member 15 which is the biasing member in the photoconductive drum 100 according to this embodiment of the present invention is fixed to a point between the hinge member 14 of the arm member 11 and the arm elongated hole 12. The other end of the spring member 15 is fixed to the cap member 2. Further, the biasing force is applied so as to shorten the length between the ends. Because of this feature, the biasing force of the spring member 15 may be applied to the arm member 11 to increase the cap-member-side virtual angle θ2 to open the arm members 11.
Further, in the photoconductive drum 100 according to this embodiment of the present invention, the photoconductive sleeve member 1 is fixed in position with respect to the cap member 2 and the wheel member 3 by engaging the end of the photoconductive sleeve member 1 in the center line direction with the cap member 2 and engaging the other end of the photoconductive sleeve member 1 in the center line direction with the wheel member 3. Then the wheel member 3 is attached to the driving shaft 4 provided in the main body of the printer 200 which is an image forming apparatus. By having this configuration, the photoconductive sleeve member 1 may be engaged with the driving shaft 4, and by rotating the driving shaft 4, it may become possible to rotate the photoconductive drum 100, thereby rotating the surface of the photoconductive sleeve member 1.
Further the printer 200 includes a photoconductive drum 100 and the charging device 19, the exposure device 20, the development device 21, and a corona transfer device 43. The photoconductive drum 100 has a photoconductive outer circumferential surface. The charging device 19 serves as charging means to charge the outer circumferential surface of the photoconductive drum 100. The exposure device 20 serves as latent image forming means to form a latent image on the charged outer circumferential surface of the photoconductive drum 100. The development device 21 serves as development means to develop the latent image on the outer circumferential surface of the photoconductive drum 100 and to form the toner image. The corona transfer device 43 serves as transfer means to transfer the toner image on the outer circumferential surface of the photoconductive drum 100 to the continuous web P as a recording medium. Further, as the photoconductive drum, the photoconductive drum 100 as described with reference to
Further, according to an embodiment of the present invention,
the sleeve inner circumferential surface pressing member 11 in the contacting unit includes two arm members 11a and 11b which are rotatably connected with respect to each other;
the arm members 11a and 11b are rotatable with respect to each other about a first virtual axis orthogonal to the center line of the photoconductive sleeve member 1 and upon being rotated, the arm members 11 (11a and 11b) can be in contact with the inner circumferential surface of the photoconductive sleeve member 1 to be disposed opposite to each other with respect to a virtual plane including the first virtual axis 14p and the center line of the photoconductive sleeve member 1;
in the state where the arm members 11 (11a and 11b) are in contact with the inner circumferential surface of the photoconductive sleeve member 1, a first-end-surface-member-side virtual angle θ2 is less than 180 degrees, the first-end-surface-member-side virtual angle θ2 being one of two virtual angles formed between two virtual lines (L1 and L2) and being the angle formed on a side of the first end surface member 2, the virtual lines (L1 and L2) extending between respective contacting sections (112a and 112b) and the first virtual axis 14p, the contacting sections (112a and 112b) being between the respective arm members 11 (11a and 11b) and the inner circumferential surface of the photoconductive sleeve member 1;
the contacting unit further includes a biasing members 15 and biasing prevention units 6c, the biasing members 15 being capable of applying a biasing force to the arm members 11 so as to increase the first-end-surface-member-side virtual angle θ2, the biasing prevention units 6c being capable of releasing the engagement between the arm members 11 and the photoconductive sleeve member 1 by decreasing the first-end-surface-member-side virtual angle θ2 against the biasing force due to the operation of the operation members 6 to release the engagement;
in the state where the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, the contacting unit is capable of engaging the first end surface member 2 with the photoconductive sleeve member 1 by applying the biasing force of the biasing members 15 to the arm members 11 to increase the first-end-surface-member-side virtual angle θ2;
the first end surface member 2 further includes an arm holding member 10 supporting the arm members 11 at to-be-held sections of the arm members 11; and
the arm holding member 10 fixes positions of the to-be-held sections of the arm members 11 with respect to the first end surface member 2 in the center line direction and rotatably supports the arm members 11 so that the arm members 11 can rotate with respect to the arm holding member 10 about respective second virtual axes parallel to the first virtual axis.
Further, according to another embodiment of the present invention,
the to-be-held section of the arm member 11 is a contact section where an arm elongated hole 12 is in contact with an arm holding axis 13, the arm elongated hole 12 being formed between the contacting section 112 and an arm connecting section, the contacting section 112 being between the arm member 11 and the inner circumferential surface of the photoconductive sleeve member 1, the arm connecting section being where the arm members 11 (11a and 11b) are rotatably connected, the arm holding axis 13 being provided at the arm holding member 10 so as to be engaged with the arm elongated hole 12;
the arm member 11 is supported by the arm holding member 10 in a manner such that the arm connecting section with respect to the first end surface member 2 in the center line direction is slidably moved; and
in the where that the arm members 11 are in contact with the inner circumferential surface of the photoconductive sleeve member 1, a virtual angle θ1 is less than 180 degrees, the virtual angle θ1 being defined as one of two angles formed between two virtual lines (La and Lb) and is an angle formed on the side opposite to the side of the first end surface member 2, the virtual lines (La and Lb) being parallel to the longitudinal directions of the arm elongated holes 12 of the respective arm members 11.
Further, according to an embodiment of the present invention,
the biasing member 15 is an elastic member with one end fixed to a point between the arm connecting section and the arm elongated hole 12 of the arm member 11 and with the other end fixed to the first end surface member 2, so that the biasing member 15 applies a biasing force to decrease the distance between the ends.
Further, according to an embodiment of the present invention,
the photoconductive sleeve member 1 is retained in position with respect to the first end surface member 2 and the second end surface member 3 by sandwiching the photoconductive sleeve member 1 with the first end surface member 2 and the second end surface member 3 in a manner such that the end of the photoconductive sleeve member 1 in the center line direction is engaged with the first end surface member 2 and the other end of the photoconductive sleeve member 1 in the center line direction is engaged with the second end surface member 3, and
at least one of the first end surface member 2 and the second end surface member 3 is able to be fixed to a driving shaft 4 of a main body of an image forming apparatus.
Further, according to an embodiment of the present invention, there is provided an image forming apparatus including:
the photoconductive drum described above;
a charging unit configured to charge the outer circumferential surface of the photoconductive drum;
a latent image forming unit configured to form a latent image on the charged outer circumferential surface of the photoconductive drum;
a development unit configured to develop the latent image on the outer circumferential surface of the photoconductive drum to form a toner image; and
a transfer unit configured to transfer the toner image on the outer circumferential surface of the photoconductive drum to a recording medium.
Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.
| Number | Date | Country | Kind |
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| 2009-047265 | Feb 2009 | JP | national |
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| Number | Date | Country | |
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| 20100221041 A1 | Sep 2010 | US |
