Patent Grant
7271823
The present document incorporates by reference the entire contents of Japanese priority documents, 2003-306688 filed in Japan on Aug. 29, 2003 and 2003-328314 filed in Japan on Sep. 19, 2003.
1) Field of the Invention
The present invention relates to an optical scanner used in image forming apparatuses such as digital copiers and color laser printers, and to an image forming apparatus utilizing the optical scanner.
2) Description of the Related Art
In recent years, with the development of high-speed color image forming apparatuses, the so-called four-drum tandem digital color copiers and color laser printers have been put to practical use. In such apparatuses, four photosensitive drums are disposed in a direction in which a recording paper is carried. A latent image is formed by exposing simultaneously by using a plurality of scanning optical systems corresponding to each of the photosensitive drums. The latent image formed is visualized in a developing unit that uses developers of different colors such as yellow (Y), magenta (M), cyan (C), and black (K). A color image is obtained by transferring the visualized images on the same recording paper one after the other such that the images are superimposed.
In the four-drum tandem image forming apparatus, as compared to a one-drum image forming apparatus, the colors can be output with the same speed as in monochrome. Therefore, the four-drum tandem image forming apparatus is advantageous for high-speed printing.
A deflector is used jointly with the scanning optical systems. Light is allowed to be incident on the deflector at different angles of incidence and a width in a sub-scanning direction of the deflector is adjusted to be same as a width of deflection of a single light beam. This enables to reduce the size and cost of the deflector.
To block noise that is developed due to rotation of the deflector and to prevent contamination of a reflecting surface of the deflector, the deflector is covered by a housing or a cover and an inlet for incident light beam and an outlet for emergent light beam are sealed up by a noise proof and dustproof transparent parallel plate.
However, if an angle of incidence of a beam that passes through the parallel plate is wide, the image forming is affected to a great extent by a figure tolerance of the parallel plate. Conventionally, technologies have been proposed in Japanese Patent Application Laid-Open Nos. 2001-290095 and H9-274134 to reduce the effect on the image forming.
Moreover, if the parallel plate is disposed near the deflector, light reflected from the parallel plate becomes ghost light and reaches a surface to be scanned, thereby forming a ghost image. Generally, the ghost image that is formed appears as straight black stripes extending in the sub-scanning direction. Conventionally, technologies to remove the ghost image have been proposed in Japanese Patent Application Laid-Open Nos. 2001-290095, H9-274134, and 2001-318335.
It is an object of the present invention to solve at least the problems in the conventional technology.
An optical scanner according to an aspect of the present invention includes: a plurality of light sources; a deflector including a deflecting-reflecting surface which deflects a plurality of bundles of light beams emitted from the plurality of light sources; a coupling lens which couples the bundles of light beams emitted from the plurality of light sources; a cylindrical lens which directs the bundles of light beams coupled by the coupling lens to the deflector; a parallel plate through which the bundles of light beams incident on and deflected from the deflector pass; and a scanning-imaging optical system which condenses the bundles of light beams deflected from the deflector on a surface to be scanned, wherein the bundles of light beams incident on the deflector have an angle between the bundles in a rotating plane of the deflector, and expressions
0.6<(θ1max−α)/(θ2+α)<1.4
and
0.6<(θ1min−α)/(θ2+α)<1.4
are satisfied, where θ1max and θ1min are maximum and minimum values of an average angle of incidence on the deflecting-reflecting surface in the rotating plane of the deflector, θ2 is a half-view angle corresponding to an effective writing width, and α is an angle of inclination of the parallel plate in the rotating plane of the deflector with respect to a main scanning direction.
An image forming apparatus according to another aspect of the present invention, which forms an electrostatic latent image on an image carrier by electrophotography, having an optical writing unit which performs optical writing on the image carrier and includes: a plurality of light sources; a deflector including a deflecting-reflecting surface which deflects a plurality of bundles of light beams emitted from the plurality of light sources; a coupling lens which couples the bundles of light beams emitted from the plurality of light sources; a cylindrical lens which directs the bundles of light beams coupled by the coupling lens to the deflector; a parallel plate through which the bundles of light beams incident on and deflected from the deflector pass; and a scanning-imaging optical system which condenses the bundles of light beams deflected from the deflector on a surface to be scanned, wherein the bundles of light beams incident on the deflector have an angle between the bundles in a rotating plane of the deflector, and expressions
0.6<(θ1max−α)/(θ2+α)<1.4
and
0.6<(θ1min−α)/(θ2+α)<1.4
are satisfied, where θ1max and θ1min are maximum and minimum values of an average angle of incidence on the deflecting-reflecting surface in the rotating plane of the deflector, θ2 is a half-view angle corresponding to an effective writing width, and α is an angle of inclination of the parallel plate in the rotating plane of the deflector with respect to a main scanning direction.
An optical scanner according to yet another aspect of the present invention includes: a plurality of light sources; a deflector including a deflecting-reflecting surface which deflects a plurality of bundles of light beams emitted from the plurality of light sources; a coupling lens which couples the bundles of light beams emitted from the plurality of light sources; a cylindrical lens which directs the bundles of light beams coupled by the coupling lens to the deflector; a scanning-imaging optical system which condenses the bundles of light beams deflected from the deflector on a surface to be scanned; and a parallel plate on an optical path between the deflector and the scanning-imaging optical system, wherein at least a pair of bundles from among the bundles of light beams incident on the deflector has an angle between each other in a rotating plane of the deflector, positions at which the pair of bundles pass through the parallel plate are separated by a distance in a sub-scanning direction, and the parallel plate is tilted in the sub-scanning direction so that when the pair of bundles are reflected at an incidence plane of the parallel plate, one of the pair of bundles with a wider average angle of incidence on the deflecting-reflecting surface in the rotating plane of the deflector is reflected towards the other one of the pair with a smaller average angle of incidence.
An image forming apparatus according to still another aspect of the present invention, which forms an electrostatic latent image on an image carrier by electrophotography, having an optical writing unit which performs optical writing on the image carrier and includes: a plurality of light sources; a deflector including a deflecting-reflecting surface which deflects a plurality of bundles of light beams emitted from the plurality of light sources; a coupling lens which couples the bundles of light beams emitted from the plurality of light sources; a cylindrical lens which directs the bundles of light beams coupled by the coupling lens to the deflector; a scanning-imaging optical system which condenses the bundles of light beams deflected from the deflector on a surface to be scanned; and a parallel plate on an optical path between the deflector and the scanning-imaging optical system, wherein at least a pair of bundles from among the bundles of light beams incident on the deflector has an angle between each other in a rotating plane of the deflector, positions at which the pair of bundles pass through the parallel plate are separated by a distance in a sub-scanning direction, and the parallel plate is tilted in the sub-scanning direction so that when the pair of bundles are reflected at an incidence plane of the parallel plate, one of the pair of bundles with a wider average angle of incidence on the deflecting-reflecting surface in the rotating plane of the deflector is reflected towards the other one of the pair with a smaller average angle of incidence.
The other objects, features, and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings.
Exemplary embodiments of an optical scanner and an image forming apparatus according to the present invention are described in detail below with reference to the accompanying drawings.
The following is a description of an optical scanner according to the present invention.
The noise proof glass 6 is disposed in an optical path of incidence and emergence of the laser beams on and from the polygon mirror 5, between the polygon mirror 5 and the scanning-imaging optical system (in the example in
The dust proof glass 9 is disposed in a window frame for emerging light of a case, such as a plastic case to prevent any dust from entering into the optical scanner that is enclosed and sealed in the case.
Optical scanning by an optical scanner for each of the scanning optical systems is described below.
The semiconductor laser 1A, based on an image signal, emits divergent light beam that is modulated. The divergent light beam that is emitted from the semiconductor laser 1A is coupled by the coupling lens 2A to a beam form that is suitable for the optical system from here onward. Each beam that is coupled is a parallel beam in the same beam form.
The beam that passes through the coupling lens 2A is formed as a line image in the main scanning direction near a deflecting-reflecting surface of the polygon mirror 5, by the cylindrical lens 3A and the virtual mirror 4A.
The polygon mirror 5 is rotated in a clockwise direction on a paper surface at roughly constant speed by a motor which is not shown, and deflects the incident light beam at a constant angular speed. The light beam, which is emitted from the semiconductor laser 1A and deflected at the polygon mirror 5, passes through the noise proof glass 6, the first scanning lens 7, and the second scanning lens 8. The light beam is focused on the photosensitive cylinder surface 10 as a converged beam due to an effect of the first scanning lens 7 and the second scanning lens 8, and is imaged as a beam spot. The converged beam performs optical scanning of the photosensitive cylinder surface 10 from a top side to a bottom side of the paper surface in
Similarly, the light beam that is emitted from the semiconductor laser 1B passes through the coupling lens 2B, the cylindrical lens 3B, the virtual mirror 4B, the polygon mirror 5, the noise proof glass 6, the first scanning lens 7, and the second scanning lens 8. The light beam is focused on the photosensitive cylinder surface 10 and imaged as a beam spot. The photosensitive drum surface 10 is scanned at a constant speed.
The two scanning optical systems which are included in the optical scanner are disposed with a certain voluntary distance between the two in the sub-scanning direction. In this case, the voluntary distance is a distance that is determined by pixel density. Therefore, two parallel scanning lines separated by a distance in the sub-scanning direction are formed simultaneously on the photosensitive drum surface 10.
The two scanning optical systems are disposed such that the light beam incident on the polygon mirror 5 from the semiconductor laser 1A and the light beam incident on the polygon mirror 5 from the semiconductor laser 1B (hereinafter, “a set of incident light beams”) have an opening angle at the deflecting-reflecting surface.
In
The noise proof glass 6 is tilted towards the sub-scanning direction. This is for causing the incident light beam with a wider average angle of incidence with the deflecting-reflecting surface in the rotating plane of the deflector in the set of incident light beams (the light beam emitted from the semiconductor laser 1B) to reflect in a direction closer to the incident light beam with a smaller average angle of incidence (light beam emitted from the semiconductor laser 1A), if the set of the incident light beams is reflected at a incidence plane of the noise proof glass 6. With such an arrangement, even if a ghost light is developed due to the reflection of the set of incident light beams at the noise proof glass 6, a ghost image can be shifted out of an effective scanning width on the photosensitive drum surface 10, thereby enabling to reduce an effect of the ghost light.
A structure of the optical scanner according to the present invention is described below concretely by citing optical system data.
1) semiconductor laser 1A
Lens data of components from the polygon mirror 5 onward is as shown below.
A shape in the main scanning direction of a first surface (L1R1) of the first scanning lens and both surfaces (L2R1 and L2R2) of the second scanning lens 8 is noncircular. Depth X in the direction of the optical axis of each surface is expressed by the following equation.
where Y is a distance from the optical axis in the main scanning direction, Rm is a radius of curvature, K is a conic constant, and An (n=1, 2, 3, . . . ) is a coefficient of higher order. If odd-order coefficients A1, A3, A5, . . . are substituted by a value other than zero, there is an asymmetric form in the main scanning direction. In the following example, only even-order is used and it is symmetric in the main scanning direction.
If Cs (Y) is let to be a radius of curvature in a surface that is orthogonal to a direction of deflection with Y as a variable, then Cs(Y) is expressed by the following equation.
Cs(Y)=1/Rs(0)+B1·Y+B2·Y2+B3·Y3+B4·Y4+B5·Y5+ . . . (2),
where Rs(0) is a radius of curvature in the sub-scanning direction at an optical axis position and Bn (n=1, 2, 3, . . . ) is a coefficient of higher order. In equation (2), if odd-order coefficients B1, B3, B5, . . . are substituted by a value other than zero, the radius of curvature in the sub-scanning direction is asymmetric with the main scanning direction.
On the other hand, a second surface (L1R2) of the first scanning lens 7 is a co-axial aspheric surface and depth X in a direction of an optical axis is expressed by the following equation.
where R is a paraxial radius of curvature in the optical axis, Y is a distance from the optical axis in the main scanning direction, K is a conic constant, and An (n=1, 2, 3, . . . ) is a coefficient of higher order.
Optical system data of the first surface (L1R1) of the first scanning lens 7 is as follows.
Optical system data of the second surface (L1R2) of the first scanning lens 7 is as follows.
Optical system data of the first surface (L2R1) of the second scanning lens 8 is as follows.
Optical system data of the second surface (L2R2) of the second scanning lens is as follows.
The refractive index of the scanning lens in usable wavelengths is 1.52724 for all.
Optical data related to an optical arrangement is shown below.
F-numbers in the outermost peripheries and a central image height in the sub-scanning direction are as shown below.
A relationship between an angle of inclination of the noise proof glass 6 with the main scanning direction and a main scanning direction field curvature when a figure of tolerance of the main scanning field curvature and the noise proof glass 6 is 400 mR is shown in table 1 for the angles of inclination of 16 degrees (first example), 12 degrees (second example), and 6 degrees (example for comparison).
As shown in table 1, in a case of the first example, a change in the field curvature of two beams in the main scanning direction (main scanning field curvature when the figure of tolerance of the noise proof glass 6 is 400 mR—main scanning field curvature) is maintained with proper balance. On the other hand, in a case of the example for comparison, since the field curvature is large, the figure of tolerance of the noise proof glass 6 is to be maintained strictly.
The following conditional equations 1 and 2 are satisfied in the first and the second examples.
0.6<(θ1max−α)/(θ2+α)<1.4 (conditional equation 1)
0.6<(θ1min−α)/(θ2+α)<1.4 (conditional equation 2)
Whereas, in the example for comparison, the conditional equation 1 is not satisfied.
The following conditional equation 3 is satisfied in the first and the second examples.
(θ1min−α)/(θ2+α)<1.0<(θ1max−α)/(θ2+α) (conditional equation 3)
Whereas, in the example for comparison, the conditional equation 3 is not satisfied.
According to the first embodiment described so far, by satisfying the conditional equations 1 and 2, the change in the field curvature in the main scanning direction of the two beams can be maintained with a proper balance. This enables to reduce an effect of the figure tolerance of the noise proof glass 6 on the imaging capability. In other words, even in a structure in which the parallel plate is disposed in an inlet and outlet for incident and emergent light beam to an from the deflector that is shared by a plurality of scanning optical systems, the effect of the figure tolerance of the parallel plate (noise proof glass 6) on the imaging capability can be reduced.
The following is a description of an optical scanner according to a second embodiment. A structure of the optical scanner is similar to that in
Since the semiconductor lasers 1A and 1B are disposed at a voluntary distance from each other in the sub-scanning direction, positions of passing of the set of incident light beams through the noise proof glass 6 are separated from each other in the sub-scanning direction. In other words, the two incident light beams are separated spatially as shown in
As shown in
In this case, no imaging takes place on the image plane since the reflected light 12a does not pass through the first scanning lens 7. Even if the reflected light 12b passes through the first scanning lens 7 and reaches the photosensitive drum surface 10, since it is shifted away substantially in the main scanning direction as shown in
With such an arrangement of the optical scanner according to the present invention, even if the ghost light is developed due to reflection of the set of incident light beams at the noise proof glass 6, the ghost image can be shifted out of the effective scanning width on the photosensitive drum surface 10, thereby enabling to reduce the effect of the ghost light.
The number of scanning optical systems which are included in the optical scanner according to the present invention is not restricted to two, and three or more than three scanning optical systems may be used. When three or more than three scanning optical systems are used, the optical scanner is to be structured such that at least one set of incident light beams from among the incident light beams emitted from a plurality of light sources to the deflector, satisfies the relationships described so far.
The structure of the optical scanner according to the present invention is described below concretely by citing optical system data.
1) semiconductor laser 1A
Lens data of components from the polygon mirror 5 onward is as shown below.
The shape in the main scanning direction of the first surface (L1R1) of the first scanning lens 7 and the both surfaces (L2R1 and L2R2) of the second scanning lens 8 is noncircular. Depth X in the direction of the optical axis of each surface is expressed by the following equation.
where Y is a distance from the optical axis in the main scanning direction, Rm is a radius of curvature, K is a conic constant, and An (n=1, 2, 3, . . . ) is a coefficient of higher order. If the odd-order coefficients A1, A3, A5, . . . are substituted by a value other than zero, there is an asymmetric form in the main scanning direction. In the following example, only ever-order is used and it is symmetric in the main scanning direction.
If Cs(Y) is let to be the radius of curvature in the surface that is orthogonal to the direction of deflection with Y as a variable, then Cs(Y) is expressed by the following equation.
Cs(Y)=1/Rs(0)+B1·Y+B2·Y2+B3·Y3+B4·Y4+B5·Y5+ . . . (2),
where Rs(0) is a radius of curvature in the sub-scanning direction at an optical axis position and Bn (n=1, 2, 3, . . . ) is a coefficient of higher order. In equation (2), if odd-order coefficients B1, B3, B5, . . . are substituted by a value other than zero, the radius of curvature in the sub-scanning direction is asymmetric in the main scanning direction.
On the other hand, the second surface (L1R2) of the first scanning lens 7 is a coaxial aspheric surface and depth X in the direction of the optical axis is expressed by the following equation.
where R is a paraxial radius of curvature in the optical axis, Y is a distance from the optical axis in the main scanning direction, K is a conic constant, and An (n=1, 2, 3, . . . ) is a coefficient of higher order.
The optical system data of the first surface (L1R1) of the first scanning lens 7 is as follows.
The optical system data of the second surface (L1R2) of the first scanning lens 7 is as follows.
The optical system data of the first surface (L2R1) of the second scanning lens 8 is as follows.
The optical system data of the second surface (L2R2) of the second scanning lens is as follows.
The refractive index of the scanning lens in usable wavelengths is 1.52724 for all.
The optical data related to the optical arrangement is shown below.
F-numbers in the outermost peripheries and the central image height in the sub-scanning direction are as shown below.
The semiconductor laser 1B is at an average angle of incidence of 37.275 degrees with the deflecting-reflecting surface in the rotating plane of the deflector. The incident light beam which is emitted from the semiconductor laser 1B is reflected when incident on the incidence plane of the noise proof glass 6, thereby developing the ghost light. The image height of the ghost image which is formed by the ghost light is approximately −170 mm. Therefore it does not affect the image plane in a range of the image height from −150 mm to 150 mm. On the other hand, the semiconductor laser 1A is at an average angle of incidence of 28.225 degrees with the deflecting-reflecting surface in the rotating plane of the deflector. The incident light beam which is emitted from the semiconductor laser 1A is reflected when incident on the incidence plane of the noise proof glass 6, thereby developing the ghost light. The image height of the ghost image which is formed by the ghost light is approximately −110 mm. Therefore, as shown in
A relationship among the main light ray, upper light ray, and lower light ray on each lens surface when an effective height of the first scanning lens 7 is 1.70 mm and the effective height of the second scanning lens 8 is 3.00 mm is as shown in the table below (in mm).
As shown in the table above, the semiconductor laser 1B is at an average angle of incidence of 28.225 degrees with the deflecting-reflecting surface in the rotating plane of the deflector. Since, the light beam which is emitted from the semiconductor laser 1B does not pass through the second scanning lens, the ghost light does not form an image on the image plane.
In this case, to shift the ghost image assuredly out of the effective scanning width, the following condition is required to be satisfied.
2θ1max−2α>θ2
where
In this example, since
Thus, according to the second embodiment, even if the light beam incident on the deflector is reflected from the parallel plate which is disposed between the deflector and the scanning-imaging optical system and the ghost light is developed, the ghost image can be shifted out of the effective scanning width, thereby enabling to reduce the effect of the ghost light.
The following is a description of the image forming apparatus according to the present invention.
The image forming apparatus 100 includes process members according to the electrophotographic process such as a charging roller 112 as a charging unit, a developing unit 113, a transfer roller 114, and a cleaning unit around the latent image carrier 111. A corona charger can also be used as a charging unit.
The optical scanner 117 is an optical writing unit that performs optical writing on the image carrier and performs exposing in the electrophotographic process. The optical scanner 117 scans a surface of the latent image carrier 111 which is charged uniformly by the charging roller 112. The electrostatic latent image that is formed is the so called negative latent image with an exposed image portion. The developing unit 113 performs inversion developing of the electrostatic latent image and the toner image is formed on the latent image carrier 111.
The image forming apparatus includes a cassette 118 which stores transfer papers P and is detachable from the laser printer 100. In the image forming apparatus shown
The transfer paper P with the toner image transferred on it is sent to a fixing unit 116 where the toner image is fixed. The transfer paper P then passes through a transporting path 121 and is discharged on a tray 123 by a pair of discharging rollers 122.
The cleaning unit 115 cleans the surface of the latent image carrier 111 on which the toner image is transferred, and paper dust and toner remained are removed.
Use of the optical scanner 117 as the optical scanner according to the present invention, enables to reduce effect on the imaging capability due the figure tolerance of the parallel plate in the optical scanner and to form a clear image.
The process of image formation is described by assuming an image formation with a single color. However, the present invention is not restricted to the image formation with a single color and can also be applied to a color image forming apparatus in which an image is formed by superimposing images of a plurality of colors. In such a case, the present invention can be applied to an image forming apparatus in which the optical writing unit is used jointly for the plurality of colors. In other words, such an image forming apparatus includes one optical writing unit and one image carrier. Optical writing is performed with an image signal for each single color and an image is developed by using a toner of the corresponding color. The developed image is transferred to a transfer paper. Next, the optical writing is performed with an image signal for another color and an image is developed by using a toner of the corresponding color. The developed image is transferred to the transfer paper. Thus, the image formation for each color is performed and the images are transferred and superimposed on the same transfer paper.
The present invention can also be applied to a so called tandem image forming apparatus in which the optical writing unit is disposed as an exposing unit for each color. In other words, such an image forming apparatus includes a plurality of optical writing units and image carriers corresponding to each color. An optical writing unit corresponding to an image signal for each color writes an image on the corresponding image carrier. The image that is written is developed by a toner of the corresponding color. The images of corresponding color are transferred and superimposed on the same transfer sheet. The tandem image forming apparatus is advantageous for light-beam writing of an image and high-speed image formation.
Although the invention has been described with respect to a specific embodiment 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 which fairly fall within the basic teaching herein set forth.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-306688 | Aug 2003 | JP | national |
| 2003-328314 | Sep 2003 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3813140 | Knockeart | May 1974 | A |
| 4862196 | Umeda et al. | Aug 1989 | A |
| 4863227 | Takanashi | Sep 1989 | A |
| 4930869 | Miyagawa et al. | Jun 1990 | A |
| 5233454 | Sakuma et al. | Aug 1993 | A |
| 5355244 | Suzuki et al. | Oct 1994 | A |
| 5408095 | Atsuumi et al. | Apr 1995 | A |
| 5426298 | Sakuma et al. | Jun 1995 | A |
| 5459601 | Suzuki et al. | Oct 1995 | A |
| 5475522 | Itabashi et al. | Dec 1995 | A |
| 5504613 | Itabashi et al. | Apr 1996 | A |
| 5557448 | Endo et al. | Sep 1996 | A |
| 5570224 | Endo et al. | Oct 1996 | A |
| 5581392 | Hayashi | Dec 1996 | A |
| 5606181 | Sakuma et al. | Feb 1997 | A |
| 5652670 | Hayashi | Jul 1997 | A |
| 5684618 | Atsuumi | Nov 1997 | A |
| 5861978 | Kamikubo | Jan 1999 | A |
| 5875051 | Suzuki et al. | Feb 1999 | A |
| 5986791 | Suzuki et al. | Nov 1999 | A |
| 6069724 | Hayashi et al. | May 2000 | A |
| 6078419 | Atsuumi | Jun 2000 | A |
| 6081386 | Hayashi et al. | Jun 2000 | A |
| 6104522 | Hayashi et al. | Aug 2000 | A |
| 6104552 | Thau et al. | Aug 2000 | A |
| 6141133 | Suzuki et al. | Oct 2000 | A |
| 6185026 | Hayashi et al. | Feb 2001 | B1 |
| 6198562 | Hayashi et al. | Mar 2001 | B1 |
| 6198563 | Atsuumi | Mar 2001 | B1 |
| 6222662 | Suzuki et al. | Apr 2001 | B1 |
| 6229638 | Sakai et al. | May 2001 | B1 |
| 6233081 | Suzuki et al. | May 2001 | B1 |
| 6317246 | Hayashi et al. | Nov 2001 | B1 |
| 6369927 | Hayashi | Apr 2002 | B2 |
| 6388792 | Atsuumi et al. | May 2002 | B1 |
| 6400391 | Suhara et al. | Jun 2002 | B1 |
| 6400488 | Nagasaka et al. | Jun 2002 | B1 |
| 6417509 | Atsuumi et al. | Jul 2002 | B1 |
| 6445482 | Hayashi | Sep 2002 | B1 |
| 6448998 | Suzuki et al. | Sep 2002 | B1 |
| 6462853 | Hayashi | Oct 2002 | B2 |
| 6509995 | Suzuki et al. | Jan 2003 | B1 |
| 6573921 | Hayashi | Jun 2003 | B2 |
| 6587245 | Hayashi | Jul 2003 | B2 |
| 6596985 | Sakai et al. | Jul 2003 | B2 |
| 6606179 | Suzuki et al. | Aug 2003 | B2 |
| 6657765 | Hayashi et al. | Dec 2003 | B2 |
| 6697183 | Atsuumi et al. | Feb 2004 | B2 |
| 6704129 | Sakai et al. | Mar 2004 | B2 |
| 6744545 | Suhara et al. | Jun 2004 | B2 |
| 6757089 | Hayashi | Jun 2004 | B2 |
| 6768506 | Hayashi et al. | Jul 2004 | B2 |
| 6771296 | Hayashi et al. | Aug 2004 | B2 |
| 6771407 | Hayashi et al. | Aug 2004 | B2 |
| 6781729 | Suzuki et al. | Aug 2004 | B2 |
| 6833940 | Suzuki et al. | Dec 2004 | B2 |
| 6956685 | Hayashi | Oct 2005 | B2 |
| 7106484 | Takeuchi et al. | Sep 2006 | B2 |
| 7116347 | Kawamura | Oct 2006 | B2 |
| 20020041419 | Takada et al. | Apr 2002 | A1 |
| 20030206323 | Itabashi | Nov 2003 | A1 |
| 20050093955 | Izumi et al. | May 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| 9-274134 | Oct 1997 | JP |
| 2001-166250 | Jun 2001 | JP |
| 2001-290095 | Oct 2001 | JP |
| 2001-318335 | Nov 2001 | JP |
| 2001-350110 | Dec 2001 | JP |
| 2002-328327 | Nov 2002 | JP |
| 2003-131152 | May 2003 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20050093955 A1 | May 2005 | US |
