Field of the Invention
The present invention relates to a fixing device included in an image forming apparatus such as an electrophotographic copying machine and printer, and a heater used in the fixing device.
Description of the Related Art
As a fixing device included in an image forming apparatus such as a copying machine and a laser beam printer, one using a film is known. Such a fixing device typically includes a cylindrical film, a plate-shaped heater which makes contact with an inner surface of the film, and a pressure member which forms a nip portion with the heater via the film. The fixing device performs fixing processing at the nip portion while conveying and heating a recording material having a toner image formed thereon to fix the toner image to the recording material.
The fixing device uses a film having a low heat capacity. The fixing device thus has an advantage of a short warm-up time, which contributes to reduced first print out time (FPOT) of the image forming apparatus. However, if small-sized sheets are continuously printed, a phenomenon in which an area of the nip portion where the recording materials do not pass rises in temperature, or a temperature rise of a non-sheet passing are, is likely to occur.
As a technique for suppressing the temperature rise of the non-sheet passing area, there is known a heater including a substrate on which a heat generation resistor having a positive resistance-temperature characteristic (positive temperature coefficient (PTC) characteristic) is formed. If a current is applied to a heat generation resistor having a high PTC characteristic in a conveyance direction of a recording material, the resistance of a sheet non-passing portion that rises in temperature increases. This can reduce the current flowing through the heat generation resistor and then reduce the amount of heat generation in the sheet non-passing portion, thereby suppressing the temperature rise of the non-sheet passing area.
The heat generation resistor is made of a paste material. Since paste materials having a high PTC characteristic have low sheet resistance, the amount of heat generation needed for the heater used in the fixing device may be difficult to obtain. Japanese Patent Application Laid-Open No. 2012-189808 discusses a heater that includes a plurality of longitudinally-divided conductive patterns connected to a heat generation resistor along a longitudinal direction. Such a heater can provide a total resistance needed for the heater used in the fixing device while using a paste material having a low sheet resistance.
However, the heater discussed in Japanese Patent Application Laid-Open No. 2012-189808 has a problem that the amount of heat generation drops locally in an area corresponding to a gap between the conductive patterns of the heater, possibly causing temperature variations of the heater in the longitudinal direction.
According to an aspect of the present invention, a heater used in a fixing device includes an elongated substrate, a first heat generation resistor formed on the substrate, and a second heat generation resistor formed on the substrate, next to the first heat generation resistor in a longitudinal direction of the substrate, the first heat generation and the second heat generation being arranged with a gap therebetween in the longitudinal direction. The heater further includes a first conductive pattern connected, along the longitudinal direction, to each one end of the first and second heat generation resistors in a transverse direction of the substrate, a second conductive pattern formed in an area of the substrate on a side opposite to the first conductive pattern in the transverse direction across the first heat generation resistor and connected to the first heat generation resistor along the longitudinal direction, the second conductive pattern not being connected to the second heat generation resistor, and a third conductive pattern formed in an area of the substrate on a side opposite to the first conductive pattern in the transverse direction across the second heat generation resistor and connected to the second heat generation resistor along the longitudinal direction, the third conductive pattern not being connected to the second conductive pattern or the first heat generation resistor, wherein a width of at least one of the first and second heat generation resistors in the transverse direction in a first area adjacent to the gap is smaller than the width in a second area, arranged adjacent to the first area, farther from the gap in the longitudinal direction than the first area.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
In the following description, a first exemplary embodiment will be described.
Next, the fixing device 7 according to the present exemplary embodiment will be described.
The film 11 serving as a fixing member includes a base layer and a release layer which is formed on the external surface of the base layer. The base layer is made of a heat resistant resin such as polyimide, polyamide-imide, and polyetheretherketone (PEEK). In the present exemplary embodiment, a 65-μm-thick heat resistant resin of polyimide is used. The release layer is formed with a coating of any one or a mixture of heat resistant resins having favorable releasability. Examples include fluorine resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), and fluorinated ethylene propylene (FEP), and silicone resins. In the present exemplary embodiment, as the release layer, a 15-μm-thick coating of fluorine resin of PFA is used. The film 11 of the present exemplary embodiment has a longitudinal length of 240 mm, which is intended to allow passing of a sheet of up to Letter size (216 mm in width), and an outer diameter of 24 mm.
A film guide 13 serves as a guide member when the film 11 rotates. The film 11 is loosely fitted to the film guide 13. In the present exemplary embodiment, the film guide 13 also has a role of supporting a surface of the heater 12, opposite to the surface where the heater 12 makes contact with the film 11. The film guide 13 is made of a heat resistant resin such as a liquid crystal polymer, phenol resin, polyphenylene sulfide (PPS), and PEEK.
The pressure roller 20 serving as a pressure member includes a core 21 and an elastic layer 22 which is formed on the external surface of the core 21. The core 21 is made of a material such as steel use stainless (SUS), steel use machinability (SUM), and aluminum (Al). The elastic layer 22 is made of a heat resistant rubber such as silicon rubber and fluorine-containing rubber, or a foamed article of silicone rubber. A release layer made of a material such as PFA, PTFE, and FEP may be formed on the external surface of the elastic layer 22. The pressure roller 20 of the present exemplary embodiment has an outer diameter of 25 mm. The elastic layer 22 is made of a 3.5-mm-thick silicone rubber. The elastic layer 22 has a longitudinal length of 230 mm. The film 11, the heater 12, and the film guide 13 are unitized into a film unit 10.
The pressure roller 20 is pressed by a pressure means (not illustrated) toward the foregoing film unit 10 at both longitudinal ends. Driving force is transmitted from a driving source (not illustrated) to a gear (not illustrated) arranged on a longitudinal end of the core 21, whereby the pressure roller 20 is rotated. The film 11 is rotated by frictional force received from the pressure roller 20 at the fixing nip portion N in accordance with the rotation of the pressure roller 20.
Next, control of the heater 12 will be described with reference to
A configuration of the heater 12 according to the present exemplary embodiment will be described with reference to
The conductive pattern 501a-1 (second conductive pattern) is connected, along the longitudinal direction, to one transverse end of the heat generation resistor 500a-1. The conductive pattern 501a-2 (third conductive pattern) is connected, along the longitudinal direction, to one transverse end of the heat generation resistor 500a-2 on the same side as the conductive pattern 501a-1 is, with a gap D from the conductive pattern 501a-1. The conductive pattern 501a-3 (first conductive pattern) is connected, along the longitudinal direction, to transverse ends of the heat generation resistor 500a-1 and the heat generation resistor 500a-2 on the side opposite from where the conductive pattern 501a-1 is. The conductive pattern 501a-3 is arranged to overlap with both the conductive patterns 501a-1 and 501a-2 in the longitudinal direction. In other words, the heat generation resistors 500a-1 and 500a-2 are electrically connected in series by the conductive patterns 501a.
If a voltage is applied between electrical contact portions 502a and 502b, a current flows through each of the heat generation resistors 500a-1 and 500a-2 in the transverse direction (conveyance direction of the recording material P) and the heat generation resistors 500a-1 and 500a-2 generate heat. In the present exemplary embodiment, the gap portion D has a width of 0.7 mm.
The substrate 100 is made of a ceramic material such as Al2O3 (aluminum oxide) and AlN (aluminum nitride). In the present exemplary embodiment, the substrate 100 is made of Al2O3 with a size of 10 mm in width, 270 mm in longitudinal length, and 1 mm in thickness. The heat generation resistor 500a is made of components including a conducting agent mainly containing RuO2 (ruthenium oxide), and glass. Other than the heat generation resistor 500a, the conductive patterns 501a and the electrical contact portions 502a and 502b are formed on the substrate 100 by screen printing with a thickness of approximately 10 μm. The heat generation resistor 500a used in the present exemplary embodiment has a sheet resistance of 500Ω/□ and a PTC characteristic (positive resistance-temperature characteristic) with a temperature coefficient of resistance (hereinafter, referred to as TCR) of 1400 ppm/° C. The value of the sheet resistance is for a thickness of 10 μm.
A protective layer 101 illustrated in
Next, a characteristic configuration of the heater 12 according to the present exemplary embodiment will be described. The heat generation resistors 500a-1 and 500a-2 each have a width V1 in the transverse direction in each of areas H1 (first areas) adjacent to the gap portion D. The width V1 is configured to be smaller than a width V2 in each of areas H2 (second areas) that is farther from the gap portion D than the area H1 is, and adjacent to the area H1. In the present exemplary embodiment, V1 is 0.86 mm, V2 is 1.0 mm, and a longitudinal length of the area H1 is 2.5 mm.
An effect of the present exemplary embodiment will be described with reference to
A configuration of a heater according to a comparative example of the present exemplary embodiment will be described with reference to
As described above, the heater 12 according to the present exemplary embodiment includes a plurality of longitudinally-divided conductive patterns connected to a heat generation resistor, which enables suppression of temperature variation in the longitudinal direction.
Next, first and second modifications of the present exemplary embodiment will be described with reference to
In the second modification, the heat generation resistors 500a-1 and 500a-2 each have a width V1a in each of first areas H1 adjacent to a gap portion D therebetween. The width V1a is configured to be smaller than a width V2a in each of second areas H2 that is farther from the gap portion D than the first area H1 is, and adjacent to the first area H1. In the second modification, the heat generation resistors 500b-1 and 500b-2 each have a width V1b in each of first areas H1 adjacent to a gap portion D therebetween. The width V1b is configured to be greater than a width V2b in each of second areas H2 that is farther from the gap portion D than the first area H1 is, and adjacent to the first area H1. In the second modification, the gap portion D between the heat generation resistors 500a-1 and 500a-2 and the gap portion D between the heat generation resistors 500b-1 and 500b-2 are arranged in the same longitudinal position. Further, in the second modification, a gap D between the conductive patterns 501a-1 and 501a-2 and a gap D between the conductive patterns 501b-1 and 501b-2 are arranged in the same longitudinal position.
The heater illustrated in
In the first heat generation segment, the amount of heat generation is greater in the center portion than at the longitudinal ends. In the second heat generation segment, the amount of heat generation is greater at the longitudinal ends than in the center portion. Such first and second heat generation segments can be independently controlled and combined to form a heat generation distribution according to the size (width) of a recording material P and suppress a temperature rise of a non-sheet passing area.
As described above, according to the second modification, the heater includes a plurality of heat generation segments, each of which includes a plurality of longitudinally-divided conductive patterns connected to a heat generation resistor, arranged in the transverse direction. Even with such a heater, temperature variation in the longitudinal direction can be suppressed.
In the present exemplary embodiment and the modifications, the heat generation resistor is divided into two. However, the number of division may be greater than two. Further, in the present exemplary embodiment, the high heat generation portions G are provided in the adjacent areas longitudinally on both sides of the gap portion D between the divided heat generation resistors. However, a high heat generation portion may be provided in either one of the adjacent areas. The high heat generation portions G according to the present exemplary embodiment and the modifications are configured to increase the amount of heat generation using the heat generation resistor having the reduced transverse width. However, the heat generation resistor may have another configuration such as an increased thickness. In the present exemplary embodiment and the modifications, the heat generation resistors is longitudinally divided according to the dividing position of the conductive pattern. However, the heat generation resistor may not be longitudinally divided, and only the conductive pattern may be divided. That is because, in the heater including divided conductive patterns, a current does not flow through the gap between the divided conductive patterns, thereby decreasing the amount of heat generation therein, even if the heat generation is continuously arranged without being divided. The configurations of the present exemplary embodiment and the modifications are thus applicable.
A second exemplary embodiment of the present invention will be described. The present exemplary embodiment differs from the first exemplary embodiment only in the pattern of the heater 12. A description of configurations similar to those of the first exemplary embodiment other than the pattern of the heater 12 will thus be omitted.
The first heat generation segment will be described. The heat generation resistor 500a and each of the conductive patterns 501a-1 and 501a-2 are not divided in the longitudinal direction. The conductive pattern 501a-1 is connected, along the longitudinal direction, to one end of the heat generation resistor 500a. The conductive pattern 501a-2 is connected, along the longitudinal direction, to a transverse end of the heat generation resistor 500a opposite from where the conductive pattern 501a-1 is. If a voltage is applied between electrodes 502a and 502c, a current flows through the heat generation resistor 500a in the transverse direction (conveyance direction of a recording material P) and the heat generation resistor 500a generates heat.
The second heat generation segment will be described. The conductive pattern 501b-1 (second conductive pattern) is connected, along the longitudinal direction, to one transverse end of the heat generation resistor 500b-1. The conductive pattern 501b-2 (third conductive pattern) is connected, along the longitudinal direction, to the transverse end of the heat generation resistor 500b-2 on the same side as the conductive pattern 501b-1 is, with a gap portion D from the conductive pattern 501b-1. The conductive patterns 501b-3 (first conductive pattern) is connected, along the longitudinal direction, to transverse ends of the heat generation resistor 500b-1 and the heat generation resistor 500b-2 on the side opposite from where the conductive pattern 501b-1 is. When seen in the conveyance direction of a recording material P, the conductive pattern 501b-3 is arranged to overlap with both the conductive patterns 501b-1 and 501b-2 in the longitudinal direction. In other words, the heat generation resistors 500b-1 and 500b-2 are electrically connected in series by the conductive patterns 501b. If a voltage is applied between an electrical contact portion 502b and the electrical contact portion 502c, a current flows through each of the heat generation resistors 500b-1 and 500b-2 in the transverse direction (conveyance direction of a recording material P) and the heat generation resistors 500b-1 and 500b-2 generate heat.
In the present exemplary embodiment, the heat generation resistor 500a has a width V1a in the transverse direction in an area (first area) overlapping with the gap portion D between the heat generation resistors 500b-1 and 500b-2 in the longitudinal direction. The width V1a is smaller than a width V2a in each of areas (second areas) not overlapping with the gap portion D. The width V1a of the first area of the heat generation resistor 500a in the transverse direction is 0.4 mm. The width V2a of the second area is 1.0 mm. The first area has a longitudinal length of 0.7 mm. The amount of heat generation per unit length of the first area is 20% greater than that of the second area. The heat generation resistor 500b has a sheet resistance of 500Ω/□, and has a PTC characteristic with TCR of 1400 ppm/° C. The heat generation resistor 500a has a sheet resistance of 3000Ω/□, and PTC characteristic with TCR of 500 ppm/° C. The first heat generation resistor 500a is provided with a high heat generation portion G to suppress a drop in the amount of heat generation in the gap portion D of the second heat generation segment. Thus, the total amount of heat generation of the first heat generation segment is smaller than that of the second heat generation segment. The heat generation resistor 500a is thus made of a resistive paste material having a higher sheet resistance and lower TCR than those of the heat generation resistor 500b.
As described above, the heater 12 of the present exemplary embodiment includes a plurality of longitudinally divided conductive patterns connected to a heat generation resistor, which enables suppression of temperature variation in the longitudinal direction.
The high heat generation portion G according to the present exemplary embodiment is configured to increase the amount of heat generation by reducing the transverse width of the heat generation resistor 500a. However, the heat generation resistor 500a may have another configuration such as an increased thickness. In the present exemplary embodiment, the heat generation resistor 500b is longitudinally divided according to the dividing position and the width of the conductive patterns 501b. However, the heat generation resistor 500b may be configured to not be longitudinally divided, and only the conductive patterns 501b may be divided.
A third exemplary embodiment of the present invention will be described. The present exemplary embodiment differs from the first exemplary embodiment only in the pattern of the heater 12. A description of configurations similar to those of the first exemplary embodiment other than the pattern of the heater 12 will thus be omitted.
The heater 12 according to the present exemplary embodiment has a similar configuration to that of the second modification of the first exemplary embodiment illustrated in
A first difference between the configuration of the present exemplary embodiment and that of the second modification of the first exemplary embodiment is that a gap D1 of the heat generation resistor 500a in the first heat generation segment and a gap D2 of the heat generation resistor 500b in the second heat generation segment do not overlap in the longitudinal direction.
A second difference lies in the configuration that a high heat generation portion G is formed in a first area of the heat generation resistor 500a-1 where the heat generation resistor 500a-1 overlaps with the gap portion D2 in the longitudinal direction. Suppose that a second area of the heat generation resistor 500a-1 is an area that is farther from the gap portion D2 in the longitudinal direction than the first area is, and adjoins the first area. The first area of the heat generation resistor 500a has a width (V1a) smaller than the width (V2a) of the second area. In the present exemplary embodiment, the first area adjoins the gap portion D1.
A third difference lies in the configuration that a high heat generation portion G is formed in a third area of the heat generation resistor 500b-2 where the heat generation resistor 500b-2 overlaps with the gap portion D1 in the longitudinal direction. Suppose that a fourth area is an area that is farther from the gap portion D1 in the longitudinal direction than the third area is, and adjoins the third area. The third area of the heat generation resistor 500b has a width (V1b) smaller than the width (V2b) of the fourth area. In the present exemplary embodiment, the third area adjoins the gap portion D2. In the present exemplary embodiment, the first and third areas have a longitudinal width of 0.7 mm. V1a is 0.7 mm. V2a is 1.0 mm. V1b is 1.1 mm. V2b is 1.5 mm. The amount of heat generation per unit length in the longitudinal direction of the first area of the heat generation resistor 500a is 25% greater than that of the second area. The amount of heat generation per unit length in the longitudinal direction of the third area of the heat generation resistor 500b is 20% greater than that of the fourth area.
In the present exemplary embodiment, the temperature drop in the gap portion D1 of the first heat generation segment is compensated by the high heat generation portion G of the second heat generation segment. The temperature drop in the gap portion D2 of the second heat generation segment is compensated by the high heat generation portion G of the first heat generation segment.
As described above, the heater 12 according to the present exemplary embodiment includes a plurality of longitudinally-divided conductive patterns connected to a heat generation resistor, which enables suppression of temperature variation in the longitudinal direction.
In the present exemplary embodiment, the heat generation resistor of each heat generation segment includes a high heat generation portion G only on one side of the gap portion in the longitudinal direction. However, as a modification of the present exemplary embodiment illustrated in
In the present exemplary embodiment, the high heat generation portion G is configured to increase the amount of heat generation by reducing the transverse width of the heat generation resistor. However, the heat generation resistor may have another configuration of an increased thickness. In the present exemplary embodiment, the heat generation resistors are longitudinally divided according to the dividing positions of the conductive patterns. However, the heat generation resistors may be configured to not be longitudinally divided, and only the conductive patterns may be divided.
A fourth exemplary embodiment of the present invention will be described. The present exemplary embodiment differs from the first exemplary embodiment only in the pattern of the heater 12. A description of configurations similar to those of the first exemplary embodiment other than the pattern of the heater 12 will thus be omitted.
The heat generation resistors 500a-1 and 500a-2 have the gap D3 therebetween. The heat generation resistors 500a-1 and 500a-3 have the gap D4 therebetween. The heat generation resistors 500b-1 and 500b-2 also have the gap D3 therebetween. The heat generation resistors 500b-1 and 500b-3 also have the gap D4 therebetween.
The heater 12 according to the present exemplary embodiment includes a conductive pattern 501a (first conductive pattern, common conductive pattern). The conductive pattern 501a is connected to the heat generation resistors 500a (500a-1, 500a-2, and 500a-3) along the longitudinal direction so that the heat generation resistors 500a lie between the conductive pattern 501a and the conductive patterns 501c (501c-1, 501c-2, and 501c-3) in the transverse direction. The heater 12 according to the present exemplary embodiment further includes a conductive pattern 501b (common conductive pattern). The conductive pattern 501b is connected to the heat generation resistors 500b (500b-1, 500b-2, and 500b-3) along the longitudinal direction so that the heat generation resistors 500b lie between the conductive pattern 501b and the conductive patterns 501c (501c-1, 501c-2, and 501c-3) in the transverse direction. The conductive patterns 501a and 501b are not longitudinally divided. The heat generation resistors and the conductive patterns of the heater 12 described above are formed symmetrically with respect to a center line X-X′ of the substrate 100.
The conductive pattern 501c-1 is provided with an electrode 504. The conductive patterns 501c-2 and 501c-3 are each provided with an electrode 505. The conductive patterns 501a and 501b are provided with electrodes 502. If a voltage is applied between each of the electrodes 502 and the electrode 504, currents flow through the heat generation resistors 500a-1 and 500b-1 in the transverse direction and the heat generation resistors 500a-1 and 500b-1 generate heat. Such a portion will hereinafter be referred to as a center heat generation segment. If a voltage is applied between each of the electrodes 502 and each of the electrodes 505, currents flow through the heat generation resistors 500a-2 and 500b-2 and the heat generation resistors 500a-3 and 500b-3 in the transverse direction and the heat generation resistors 500a-2 and 500b-2 and the heat generation resistors 500a-3 and 500b-3 generate heat. Such portions will hereinafter be referred to as end heat generation segments. Power can be independently supplied to the center heat generation segment and the end heat generation segments via triacs 50 and 51, respectively. The heat generation area of the center heat generation segment has a longitudinal length of 158 mm which corresponds to an A5 size (149 mm×210 mm), i.e., a regular size of a recording material P. The heat generation areas including the center heat generation segment and the end heat generation segments have a total longitudinal length of 225 mm which corresponds to an A4 size (210 mm×297 mm), i.e., a regular size of a recording material P.
A control for switching the heat generation segments of the heater 12 in the fixing device 7 according to the present exemplary embodiment will be described with reference to the flowchart of
Next, a characteristic configuration of the present exemplary embodiment will be described with reference to
The areas adjacent to the gap portion D3 in the longitudinal direction will be referred to as first areas (H1). The areas that are farther from the gap portion D3 in the longitudinal direction than the first areas are and adjoin the first areas will be referred to as second areas (H2). The heat generation resistors 500a-1 and 500a-2 have a width V1a in the transverse direction in the first areas (H1). The width V1a is smaller than the width V2a of the heat generation resistors 500a-1 and 500a-2 in the transverse direction in the second areas (H2). Similarly, the heat generation resistors 500b-1 and 500b-2 have a width V1b in the transverse direction in the first areas (H1). The width V1b is smaller than the width V2b of the heat generation resistors 500b-1 and 500b-2 in the transverse direction in the second areas (H2). In such a manner, the widths of the heat generation resistors are reduced to lower the resistances, whereby high heat generation portions G are formed locally near the gap portion D3. At least either one of the first areas of the heat generation resistors 500a-1 and 500a-2 may have the transverse width V1a smaller than the transverse width V2b of the second areas.
It can be seen that with such a configuration, a drop in the amount of heat generation in the gap portions D3 and D4 of the heater 12 is compensated by the high heat generation portions G configured in the first areas, whereby temperature variation in the longitudinal direction of the heater 12 is suppressed.
The same experiment as that of the present exemplary embodiment was performed by using the heater 12 of the comparative example to measure the amounts of temperature drop ΔT1L and ΔT1R in the areas of the film 11 corresponding to the gap portions D3 and D4, respectively. The measurements were 12.0° C. with respect to an average temperature of 160° C. in the areas not corresponding to the gap portions D3 and D4. A whole-surface solid image was printed by using the heater 12 of the comparative example under the same condition as in the present exemplary embodiment. As a result, fixing failures of approximately 2 mm in width occurred in the positions corresponding to the gap portions D3 and D4. The reason for the occurrence of the fixing failures is considered to be that the heater 12 of the comparative example is not able to compensate a drop in the amount of heat generation in the gap portions D3 and D4.
As described above, the heater 12 according to the present exemplary embodiment includes a plurality of longitudinally-divided conductive patterns connected to heat generation resistors, which enables suppression of temperature variation in the longitudinal direction.
The high heat generation portions G according to the present exemplary embodiment are configured to increase the amount of heat generation by reducing the widths of the heat generation resistors in the transverse direction. However, the heat generation resistors may have another configuration such as an increased thickness. In the present exemplary embodiment, the heat generation resistors are longitudinally divided according to the dividing positions of the conductive patterns. However, as illustrated in
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2015-022676, filed Feb. 6, 2015, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2015-022676 | Feb 2015 | JP | national |
Number | Name | Date | Kind |
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7283145 | Kato | Oct 2007 | B2 |
20030196999 | Kato | Oct 2003 | A1 |
20090230114 | Taniguchi | Sep 2009 | A1 |
20140027441 | Mine | Jan 2014 | A1 |
Number | Date | Country |
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2007025474 | Feb 2007 | JP |
2012-189808 | Oct 2012 | JP |
2014-139660 | Jul 2014 | JP |
Number | Date | Country | |
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20160234882 A1 | Aug 2016 | US |