Patent Grant
8768225
This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2011-070955 filed Mar. 28, 2011.
The present invention relates to an image forming apparatus.
According to an aspect of the invention, there is provided an image forming apparatus including: a rotating image carrier; a charging device that charges an outer surface of the image carrier; a latent image forming device that forms a latent image on the outer surface of the charged image carrier; a developing device that has a developer container that stores a developer including a toner and a carrier, and a developer holder that holds the developer stored in the developer container on the outer surface and rotates and transports the developer toward a developing region that faces the image carrier, and that develops the latent image of the image carrier as a visible image; a voltage application unit that applies a voltage to the developer holder, and that generates a potential difference between the image carrier and the developer holder to form an electric field, by which a toner is directed toward the latent image of the image carrier from the developer holder, in a developing region; and a transfer device that transfers the visible image of the image carrier to a medium, wherein the developer holder having a concavo-convex portion having a convex portion and a concave portion is provided in an outer surface thereof and formed such that the volume resistivity of a portion corresponding to the convex portion is set to be larger than the volume resistivity of a portion corresponding to the concave portion.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
Next, although specific examples (hereinafter referred to as Examples) of an exemplary embodiment of the invention will be described referring to the drawings, the invention is not limited to the following Examples.
In addition, in order to make the invention more easily understood, in the drawings, the front-and-rear direction is defined as an X-axis direction, the right-and-left direction is defined as a Y-axis direction, and the up-and-down direction is defined as a Z-axis direction.
Additionally, directions or sides shown by arrows X, −X, Y, −Y, Z, and −Z are defined as a front direction, a rear direction, a right direction, a left direction, an up direction, and a down direction, respectively, or are defined as front side, rear side, right side, left side, upper side, and lower side, respectively.
Additionally, in the drawings, a symbol in which “.” is described in “O” means an arrow that faces the front of a sheet from the back thereof, and a symbol in which “X” is described in “O” means an arrow that faces the back of the sheet from the front thereof.
In addition, in the following description using the drawings, illustration of those other than members required for description are appropriately omitted for easy understanding.
In
The automatic document feeder U1 has an document feed unit TG1 on which plural documents G1 to be copied are stacked and placed, and a document ejection unit TG2 to which a document G1 transported through a document reading position on the document platen PG from the document feed unit TG1 is ejected.
The image forming apparatus body U2 has an operation unit UI through which a user performs input operation of operation command signals, such as a copy start, an exposure optical system A, and the like.
The reflected light from a document transported on the document platen PG by the automatic document feeder U2 or an document manually placed on the document platen PG is converted into electrical signals of red R, green G, and blue B by a solid-state imaging device CCD via the exposure optical system A.
The image conversion unit IPS converts and temporarily stores electrical signals of RGB input from a solid-state imaging device CCD into image information of black K, yellow Y, magenta M, and cyan C, and outputs the image information to a latent image forming device drive circuit DL as image information for formation of a latent image at a preset timing.
In addition, when the image of a document is a unicolor image, so-called monochrome, image information of black K only is input to the latent image forming device drive circuit DL.
The latent image forming device drive circuit DL has respective latent image forming device drive circuits (not shown) of respective colors Y, M, C and K, and outputs latent image forming device driving signals according to input image information to latent image writing light irradiation units (not shown) for respective colors of a latent image forming device ROS at a preset timing.
Visible image forming devices Uy, Um, Uc, and Uk arranged above the latent image forming device ROS, are devices that form toner images as an example of visible images of respective colors of yellow Y, magenta M, cyan C, and black K, respectively.
From respective latent image formation light irradiation units (not shown) of the latent image forming device ROS, laser beams Ly, Lm, Lc, and Lk of Y, M, C, and K, are irradiated as an example of latent image writing light. The laser beams Ly, Lm, Lc, and Lk enter rotating image carriers PRy, PRm, PRc, and PRk, respectively.
The visible image forming device Uy for Y color has an image carrier PRy, a charging roller CRy as an example of a charging device, a developing device Gy, and a primary transfer roller T1y as an example of a primary transfer device, and an image carrier cleaner CLy, and all the visual image forming devices Um, Uc, and Uk are configured similarly to the above visible image forming device Uy of Y color.
The respective image carriers PRy, PRm, PRc, and PRk are uniformly charged by the charging rollers CRy, CRm, CRc, and CRk, respectively, and then electrostatic latent images are formed on the surface of the image carriers by the laser beams Ly, Lm, Lc, and Lk at image writing positions Q1y, Q1m, Q1c, and Q1k. The electrostatic latent images of the outer surfaces of the image carriers PRy, PRm, PRc, and PRk are developed as toner images by the developing devices Gy, Gm, Gc, and Gk in developing regions Q2y, Q2m, Q2c, and Q2k.
The developed toner images are transported to primary transfer regions Q3y, Q3m, Q3c, and Q3k that come into contact with an intermediate transfer belt B as an example of an intermediate transfer body. In the primary transfer regions Q3y, Q3m, Q3c, and Q3k, primary transfer voltages with polarity opposite to the charging polarity of toners are applied to primary transfer rollers T1y, T1m, T1c, and T1k, which are arranged on the reverse side of the intermediate transfer belt B, at a predetermined timing from a power circuit E controlled by a control unit C.
The toner images on the respective image carriers PRy to PRk are primarily transferred to intermediate transfer belt B by primary transfer rollers T1y, T1m, T1c, and T1k. The residual toners on the surfaces of the image carriers PRy, PRm, PRc, and PRk after the primary transfer are cleaned by the image carrier cleaners CLy, CLm, CLc, and CLk as examples of image carrier cleaners.
A belt module BM as an example of an intermediate transfer device that is movable up and down and is capable of being pulled out forward is arranged above the image carriers PRy to PRk. The belt module BM has the intermediate transfer belt B, a tension roller Rt as an example of a tensioning member, a walking roller Rw as an example of a meandering preventing member, an idler roller Rf as an example of a driven member, a back-up roller T2a as an example of a secondary transfer facing member serving also as a driving roller as an example of a driving member, and the primary transfer rollers T1y, T1m, T1c and T1k. A belt back-up roller Rt+Rw+Rf+T2 as an example of an intermediate transfer body supporting member is constituted by the tension roller Rt, the walking roller Rw, the idler roller Rf, and the back-up roller T2a serving also as a driving roller. The intermediate transfer belt B is supported so as to be rotatable and movable by the belt back-up roller Rt+Rw+Rf+T2a. Accordingly, an intermediate transfer belt drive unit is constituted by a drive unit that rotates the back-up roller T2a serving also as a driving roller, the belt back-up roller Rt+Rw+Rf+T2a, and the like.
A secondary transfer roller T2b as an example of a secondary transfer member is arranged to face the surface of the intermediate transfer belt B that comes into contact with the back-up roller T2a, and a secondary transfer device T2 of Example 1 is constituted by the respective rollers T2a and T2b. Additionally, a secondary transfer region Q4 is formed in a region where the secondary transfer roller T2b and the intermediate transfer belt B face each other.
The toner images sequentially superimposed and transferred onto intermediate transfer belt B by the primary transfer rollers T1y, T1m, T1c, and T1k in the primary transfer regions Q3y, Q3m, Q3c, and Q3k are transported to the secondary transfer region Q4.
A transfer device T1y to T1k+T2+B of Example 1 is constituted by the primary transfer rollers T1y, T1m, T1c, and T1k, the intermediate transfer belt B, and the secondary transfer device T2.
Three guide rails GR and GR as an example of a pair of right and left guide parts that support sheet feed trays TR1 to TR3 as an example of a medium feed part so as to be capable of entering and leaving back and forth are provided below the latent image forming device ROS. Recording sheets S as an example of a medium are accommodated in the sheet feed trays TR1 to TR3. The recording sheets S are taken out by a pickup roller Rp as an example of a medium take-out member, and are separated one by one by a separation roller Rs as an example of a separation member. A recording sheet S separated by the separation roller Rs is sent to a registration roller Rr as an example of a medium transport timing adjusting member by sheet transport rollers Ra as an example of plural transport members. Plural sheet transport rollers Ra are provided along a transport path SH formed by a medium guide member, a so-called sheet guide, and a registration roller Rr is arranged on the upstream side in the sheet transport direction of the secondary transfer region Q4. A sheet transport device SH+Ra+Rr is constituted by the transport path SH, the sheet transport rollers Ra, the registration roller Rr, and the like.
The registration roller Rr transports the recording sheet S to the secondary transfer region Q4 in accordance with the timing when the toner images formed on the intermediate transfer belt B are transported to the secondary transfer region Q4. When the recording sheet S passes through the secondary transfer region Q4, the back-up roller T2a is grounded, namely, earthed and secondary transfer voltages with polarity opposite to the charging polarity of the toners is applied to the secondary transfer roller T2b at a predetermined timing from the power circuit E controlled by the control unit C. At this time, the toner images on the intermediate transfer belt B are transferred to the recording sheet S by the secondary transfer device T2.
The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLb as an example of an intermediate transfer body cleaner.
The recording sheet S to which the toner images are secondarily transferred is transported to a fixing device F. The fixing device F has a heating roller Fh as an example of a heating and fixing member and a pressurizing roller Fp as an example of a pressurizing and fixing member, and when passing through the fixing region Q5 that is a pressure contact region between the heating roller Fh and the pressurizing roller Fp, unfixed toner images of the surface of the recording sheet S are heated and fixed. The recording sheet S on which the toner images are heated and fixed is ejected to a sheet ejection tray TRh as an example of a medium ejection part by an ejection roller Rh as an example of a medium ejection member.
In addition, a mold release agent for improving the mold releasing performance of the recording sheet S from the heating roller Fh is applied to the surface of the heating roller Fh by a mold release agent applicator Fa.
Toner cartridges Ky, Km, Kc, and Kk as an example of a developer replenishing containers that store respective Y, M, C, and K developers are arranged above the belt module BM. The developer contained in the respective toner cartridges Ky, Km, Kc, and Kk are replenished to the respective developing devices Gy, Gm, Gc, and Gk from developer replenishing channels (not shown) in response to consumption of the developer of the developing devices Gy, Gm, Gc, and Gk.
In
Additionally, the guide rail GR that supports the sheet feed trays TR1 to TR3, and the pickup roller Rp, the separation roller Rs, the sheet transport rollers Ra, and the like that perform sheet feeding from the respective sheet feed trays TR1 to TR3 are supported on the lower frame body LF.
(Developing Device)
In addition, since the developing devices Gy, Gm, Gc, and Gk have the same configuration, the developing device Gy will be described below, and description of the other developing devices Gm, Gc, and Gk will be omitted.
In
The developer container V has a developer container body 1, and a developer container cover W as an example of a lid member that covers an upper end of the body. A front-side connecting member 3 that protrudes forward as shown in
In
In
A circulation stirring chamber 6+7 of Example 1 is constituted by the first stirring chamber 6 and the second stirring chamber 7.
In
(Developing Roller)
In
The magnet roller 8 has a developing magnetic pole S1 that is arranged to face the image carrier PRy, a layer-thickness-regulating magnetic pole N2 that is arranged on the upstream side of the developing magnetic pole S1 in the rotational direction of the developing sleeve 9 and is arranged to face the layer thickness regulating member SK, a transporting magnetic pole N1 that is arranged on the downstream side of the developing magnetic pole S1 in the rotational direction of the developing sleeve 9, a pickoff magnetic pole S2 as an example of a developer peeling-off magnetic pole that is arranged on the downstream side of the transporting magnetic pole N1 in the rotational direction of the developing sleeve 9, and a pickup magnetic pole 53 as an example of a developer attracting magnetic pole that is arranged between the pickoff magnetic pole S2 and the layer-thickness-regulating magnetic pole N2.
In
In
In
In addition, in Example 1, the volume resistivity of a carrier is set to be larger than the volume resistivity of the conductor of the conductive layer 14, and the volume resistivity of the insulating layer 13a is larger than at least the volume resistivity of the carrier, and the insulating layer preferably has insulation.
In
In
In
In
The stirring and transporting blade R1b is provided toward the front-side inflow portion E1 from the rear side inflow portion E2 in order to convey a developer in a first transport direction Ya on the front side from the rear side. The reverse transporting blade R1c is provided near the discharge port 3a1, and transports a developer in a direction opposite to the transport direction of the stirring and transporting blade Rib, thereby causing the developer to flow into the second stirring chamber 7 from the first stirring chamber 6. The rotating shaft R1a is rotatably supported by a front surface wall of the left portion 3a of the front-side connecting member 3 and a rear surface wall of the developer container body 1, and the gear G1 is fixed to a rear end portion of the rotating shaft R1a, that is, an X-side end of
Additionally, the second stirring member R2 also has a second rotating shaft R2a, a stirring and transporting blade R2b, and a reverse transporting blade R2c. The stirring and transporting blade R2b is provided toward the rear-side inflow portion E2 from the replenishing port 3b1 in order to convey a developer in a second transport direction Yb on the rear side from the front side. In
In
The developing device Gy is constituted by the developer container V, the developing roller R0, the first stirring member R1, and the second stirring member R2, and the like.
(Power Circuit)
Although a power circuit E1 connected to the charging rollers CRy to CRk, a power circuit E2 connected to the developing roller R0, and a power circuit E3 connected to the primary transfer rollers T1y to T1k are described below, the power circuits E1 to E3 of the respective colors Y to K are similarly configured, only the power circuits E1 to E3 of Y color will be described, and the description of the power circuits E1 to E3 for the other colors M to K will be omitted.
In
In
The power circuit E2 for development as an example of a voltage application unit is connected to the developing sleeve 9 of the developing roller R0 in the developing device Gy. The power circuit E2 for development applies a developing voltage V3 to the developing sleeve 9, to generate a potential difference V2-V3 between the image carrier PRy and the developing sleeve 9 to form, on the developing region Qty, an electric field by which a toner is directed toward a latent image of the image carrier PRy from the developing sleeve 9.
In addition, the respective voltages V1 to V3 of Examples 1 are set so as to satisfy V1<V3<V2. Accordingly, in Example 1, the potential difference V2-V3 between the latent image of the image carrier PRy and the developing roller R0 becomes positive, while a potential difference V1-V3 between portions other than the latent image of the image carrier PRy, and the developing roller R0 becomes negative. Thereby, a toner that has negative polarity moves toward the latent image of the image carrier PRy from the developing roller R0.
A primary transfer voltage V4 for transferring the toner on the image carrier PRy to the intermediate transfer belt B is applied to the primary transfer roller T1y. In addition, a secondary transfer voltage that transfers the toner transferred onto the intermediate transfer belt B to a recording sheet S from a power circuit (not shown) is applied to the secondary transfer device T2.
(Operation of Example 1)
In the copying machine U of Example 1 having the above configuration, when a job as an example of an image formation operation is performed, the charging rollers CRy to CRk charge the image carriers PRy to PRk, and the latent image forming device ROS forms electrostatic latent images on the image carriers PRy to PRk. The electrostatic latent images are developed as toner images by the developing roller R0 of developing devices Gy to Gk in the developing regions Q2y to Q2k. The toner images are transferred to a recording sheet S via the transfer devices T1y to T1k+T2+E.
At this time, in the developing devices Gy to Gk of Example 1, a developer stored in the developer container V receives a magnetic force from the magnet roller 8, and is attracted to and held by the outer surface of the developing sleeve 9 that rotates, and is transported toward the developing regions Q2y to Q2k.
In
Additionally, in the developing devices Gy to Gk of Example 1, the developing voltage V3 is applied to the developing sleeve 9, and the potential differences V1-V3 and V2-V3 are generated between the image carriers PRy to PRk and the developing sleeve 9 to form an electric field. Here, as the developing regions Q2y to Q2k are approached, the spacing between the image carriers PRy to PRk and the developing sleeve 9 becomes narrow, and the electric field between the image carriers PRy to PRk and the developing sleeve 9 becomes strong.
In the developing regions Q2y to Q2k, toner in a developer that is nonmagnetic and has negative polarity receives a force from a developing electric field on the basis of the potential difference V2-V3 generated between the latent images of the image carriers PRy to PRk and the developing sleeve 9, and moves toward the latent images, and the latent images are developed as toner images.
When the developer is transported to the developing regions Q2y to Q2k, as shown in
When a large amount of negative electric charge is injected into a developer, a carrier charged with positive polarity as well as toner will have large negative polarity, will receive a force from an electric field similarly to toner and move onto the image carriers PRy to PRk. As result, a so-called BCO (Bead Carry Over) may occur and the quality of an image on a recording sheet S may deteriorate.
Additionally, the concavo-convex portion 11 is provided in the outer surface of the developing sleeve 9 of Example 1, and the spacing between the developing sleeve 9 and the image carriers PRy to PRk in the developing regions Q2y to Q2k differs in the groove portion 12 and the convex portion 13. That is, the spacing between the outer surfaces of the image carriers PRy to PRk and the developing sleeve 9 is L1+H1 when the groove portion 12 passes through the developing regions Q2y to Q2k, whereas the spacing between the outer surfaces of the image carriers PRy to PRk and the developing sleeve 9 becomes narrow, by H1 and becomes L1, compared to the spacing in the case of the groove portion 12 when the convex portion 13 passes through the developing regions Q2y to Q2k.
Accordingly, in the developing sleeve having the concavo-convex portion, as for the magnitude of an electric field produced in the developing regions Q2y to Q2k, the electric field between an image carrier and a convex portion becomes larger than the electric field between an image carrier and a concave portion. Hence, in the developing sleeve having the concavo-convex portion, compared to a developer held on the concave portion, a larger amount of charger injection is performed on a developer held on the convex portion, and ECO is apt to occur in this developer. Particularly, as the spacing L1 between the image carriers PRy to PRk and the developing sleeve 9 is smaller, a difference in the magnitude of electric fields between a concave portion and a convex portion is apt to become noticeable.
That is, when the volume resistivity of a portion corresponding to a convex portion is not configured so as to be larger than the volume resistivity of a portion corresponding to a concave portion as in the related art, and when charge flows through the developing sleeve, the charge is apt to be injected into a developer on the convex portion from the convex portion. Thus, there is a case where excessive charge injection is performed under a strong electric field when passing through a developing region.
In contrast, in Example 1, the insulating layer 16 is provided on the outer peripheral surface 13a of the convex portion 13, and the volume resistivity of the portion corresponding to the convex portion 13 is made larger than the volume resistivity of the portion corresponding to the groove portion 12. Accordingly, in the developing sleeve 9 of Example 1, charge flows in the conductive layer 14 with small volume resistivity and charge injection is performed on the developer on the groove portions 12, whereas charge is intercepted in the insulating layer 16 with large volume resistivity, and the charge is not easily injected into the developer on the outer peripheral surface 13a of the convex portion 13 from the inside of the convex portion 13.
That is, in the developing sleeve 9 of Example 1, the charge injection is not easily performed on the developer on the convex portion 13. As a result, when passing the developing regions Qty to Q2k, the spacing is narrow, and excessive charge injection into the carrier particularly under a strong electric field is reduced. Accordingly, in Example 1, compared with the related-art configuration, excessive charge injection in the convex portion 13 is reduced, and movement of the carrier to the image carriers PRy to PRk is reduced.
Next, although Example 2 of the invention will be described, in the description of this Example 2, the same reference numerals will be given to constituent elements corresponding to the constituent elements of Example 1, and the detailed description thereof will be omitted.
Although this Example 2 is different from Example 1 in respect of the following points, Example 2 is configured similarly to Example 1 in others points.
In
(Operation of Example 2)
The copying machine U of Example 2 having the above configuration is configured similarly to Example 1 except that the developing sleeve 9 is formed with the U groove 12′ having a U-shaped cross-section. Accordingly, also in Example 2, similarly to Example 1, compared with the related-art configuration, excessive charge injection in the convex portion 13′ is reduced, and movement of the carrier to the image carriers PRy to PRk is reduced.
Next, although Example 3 of the invention will be described, in the description of this Example 3, the same reference numerals will be given to constituent elements corresponding to the constituent elements of Example 1, and the detailed description thereof will be omitted.
Although this Example 3 is different from Example 1 in respect of the following points, Example 3 is configured similarly to Example 1 in others points.
In
(Operation of Example 3)
The copying machine U of Example 3 having the above configuration is configured similarly to Example 1 except that the developing sleeve 9 is formed with the V groove 12″ having a V-shaped cross-section. Accordingly, also in Example 3, similarly to Example 1, compared with the related-art configuration, excessive charge injection to the carrier in the convex portion 13 is reduced, and movement of the carrier to the image carriers PRy to PRk is reduced.
Next, although Example 4 of the invention will be described, in the description of this Example 4, the same reference numerals will be given to constituent elements corresponding to the constituent elements of Example 1, and the detailed description thereof will be omitted.
Although this Example 4 is different from Example 1 in respect of the following points, Example 4 is configured similarly to Example 1 in others points.
In
(Operation of Example 4)
The copying machine U of Example 4 having the above configuration is configured similarly to Example 1 except that the developing sleeve 9 is formed with the twill line-like groove portions 22. Accordingly, also in Example 4, similarly to Example 1, compared with the related-art configuration, excessive charge injection to the carrier in the convex portion 23 is reduced, and movement of the carrier to the image carriers PRy to PRk is reduced.
Next, although Example 5 of the invention will be described, in the description of this Example 5, the same reference numerals will be given to constituent elements corresponding to the constituent elements of Example 1, and the detailed description thereof will be omitted.
Although this Example 5 is different from Example 1 in respect of the following points, Example 5 is configured similarly to Example 1 in others points.
In
(Operation of Example 5)
The copying machine U of Example 5 having the above the configuration is provided with the insulated convex portion 32, and the overall convex portion is made of an insulator. Hence, in the developing sleeve 9 of Example 5, charge does not easily flow to the insulated convex portion 32. Accordingly, also in Example 5, similarly to Example 1, compared with the related-art configuration, excessive charge injection to the carrier in the insulated convex portion 32 is reduced, and movement of the carrier to the image carriers PRy to PRk is reduced.
(Modifications)
Although the Examples of the invention have been described in detail, the invention is not limited to the above Examples, and various modifications can be made thereto within the concept of the invention set forth in the claims. Modifications (H01) to (H04) of the invention are illustrated below.
(H01) Although the copying machine U has been illustrated as an example of the image forming apparatus in the above respective Examples, the invention is not limited thereto, and can be applied to a printer, a facsimile machine, or a multifunction device including these plural functions.
(H02) Although the configuration in which only one insulating layer 16 is provided on the outer peripheral surface 13a or 23a of the convex portion 13 or 23 is illustrated in the above Examples 1 to 4, the invention is not limited thereto. For example, the configuration in which plural insulating layers 16 are formed on the convex portion 13 or 23, and the convex portion 13 or 23 has multilayer structure may be adopted. Additionally, although it is desirable that the insulating layer 16 constitutes the outer peripheral surface 13a or 23a, a configuration in which the insulating layer is provided in layers in a radial midway portion of the convex portion 13 may be adopted.
(H03) In the above Examples 1 to 5, it is desirable that the developing sleeve 9 has the configuration that has the conductive layer 14 and the insulating layer 16 of the convex portion 13, 23, or 32. However, the invention is not limited thereto. The volume resistivity of the portion corresponding to the convex portion 13, 23, or 32 may be set to be larger than the volume resistivity of the portion corresponding to the concave portion 12 to 12″, 22, or 33. Accordingly, for example, instead of the insulating layer, a configuration of a high resistive layer that has a larger volume resistivity than the conductive layer and a smaller volume resistivity than the insulating layer may be adopted.
(H04) In the above Examples 1 to 4, as for the concavo-convex portions 11, 11′, 11″, 21 and 31, the configuration formed by the concave portion 12 to 12″ and 33 parallel to the axial direction, and the convex portion 13 or 32 pinched by the concave portions 12, 12′, 12″, and 33, or the configuration formed by the concave portion 22 obliquely formed in the axial direction and the convex portion 23 pinched by the concave portions 22 are illustrated. However, the invention is not limited thereto.
For example, in
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-070955 | Mar 2011 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5879849 | Sawada et al. | Mar 1999 | A |
| 20090110445 | Yamada | Apr 2009 | A1 |
| 20090214271 | Yamada et al. | Aug 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| A-2005-173141 | Jun 2005 | JP |
| 2006301165 | Nov 2006 | JP |
| A-2010-2927 | Jan 2010 | JP |
| A-2010-197948 | Sep 2010 | JP |
| 2011069898 | Apr 2011 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20120251189 A1 | Oct 2012 | US |
