1. Field of the Invention
The present invention relates to an ink jet recording head and an ink jet recording apparatus using the ink jet recording head for performing the recording operation by discharging a recording liquid onto the recording surface of a recording medium.
2. Related Background Art
In an ink jet recording head, an electrothermal energy conversion element arranged in a recording liquid chamber is heated by being supplied with an electrical pulse as a recording signal thereby to impart thermal energy to the ink. Utilizing the bubble pressure generated by the bubbling (boiling) of the recording liquid due to the phase change of the recording liquid, minute ink droplets are discharged from at least a minute discharge port thereby to perform the recording operation on a recording medium.
The electrothermal energy conversion element of this ink jet recording head is heated and the interior of the recording liquid chamber is exposed to a high temperature. Desirably, therefore, the ink having the properties thereof not changed at a high temperature is selected while at the same time covering the various elements on the substrate with a protective film to protect the electric circuit elements from thermal damage. Also, the metal surface is liable to be corroded by a water hammer when the heated bubbles are extinguished, and therefore it is desirable to provide a protective film (anti-cavitation film).
In the conventional ink jet recording head, at least an electrothermal energy conversion element and at least an electrical circuit element are mounted on a substrate, and a protective film is formed on the assembly to give a heat resistance. The resulting assembly is formed with an anti-cavitation film over the entire surface thereof, followed by forming a discharge port forming member thereon. The discharge port forming member includes a flow path wall for defining a flow path in accordance with each electrothermal energy conversion element and a discharge port communicating with an external unit from the flow path and adapted to discharge the ink. This configuration exhibits the effect of protecting the electrothermal energy conversion element and the electrical circuit element. Nevertheless, the following problem is posed.
Firstly, the ill compatibility between a tantalum (Ta) film generally used as an anti-cavitation film and the discharge port forming member made of a synthetic resin causes the problem of a low adhesion. A low adhesion between the substrate and the discharge port forming member gives rise to a solution leakage from the flow path and the displacement of the discharge port, thereby sometimes making it impossible to perform the desired recording operation.
Secondly, an inspection pad is required to check the insulation between the protective film formed under the anti-cavitation film and the electrothermal energy conversion element and the electrical circuit element, thereby undesirably increasing the size of the substrate.
In order to solve the two problems described above, Japanese Patent Application Laid-Open No. 2002-79672 discloses a recording head comprising a first metal film as an anti-cavitation film covering the upper part of a recording element and a second metal film as an anti-cavitation film covering the upper part of an electrical circuit element, where the first and second metal films are provided in the shape of a pair of combs and are arranged in opposed relation with each other. This recording head can improve the adhesion between the substrate and the discharge port forming member due to a reduced ratio which the anti-cavitation film represents of the substrate. Further, the provision of an inspection pad on each of the first and second metal films described above makes it possible to inspect the protective film for a defect without increasing the substrate size.
However, the recording head disclosed in the patent publication described above comprises an inspection electrode pad for each of the first and second metal films, with the result that the substrate size is increased proportionately. To reduce the size of the substrate, therefore, the arrangement of the inspection pad is required to be more optimized.
An object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus using the ink jet recording head, in which the adhesion between a substrate and a discharge port forming member can be improved and the arrangement of an inspection pad can be optimized more thereby to reduce the substrate size further.
Another object of the invention is to provide an ink jet recording head and an ink jet recording apparatus using the ink jet recording head, the ink jet recording head comprising a substrate, a plurality of recording elements for generating the discharge energy for discharging ink droplets of a recording liquid from at least a discharge port, the recording elements forming a recording element row on the substrate, a plurality of electrical circuit elements arranged in a row adjacently to the recording element row on the substrate for driving the recording elements, at least a conductive belt-like recording element protecting section for covering the upper part of the recording element row, at least a conductive belt-like electrical circuit element protecting section electrically connected with the recording element protecting section for covering the upper part of the electrical circuit element row, and an inspection electrode pad adapted to be electrically connected to the recording element protecting section and the electrical circuit element protecting section.
Still another object of the invention is to provide an ink jet recording head and an ink jet recording apparatus using the ink jet recording head, the ink jet recording head comprising a substrate, at least a first ink supply port provided on the substrate, a plurality of recording elements forming a first recording element row arranged in a row on each of the two sides of the first ink supply port on the substrate for generating the discharge energy for discharging ink droplets of a recording liquid, a plurality of electrical circuit elements forming a first electrical circuit element row arranged in a row outside the first ink supply port with respect to the first recording element row for driving the recording elements, at least a conductive belt-like first recording element protecting section for covering the upper part of the first recording element row, at least a conductive belt-like first electrical circuit element protecting section electrically connected with the first recording element protecting section for covering the upper part of the first electrical circuit element row, at least a second ink supply port formed on the substrate, a plurality of recording elements forming a second recording element row arranged in a row on each of the two sides of the second ink supply port on the substrate for generating the discharge energy to discharge ink droplets of the recording liquid from at least a discharge port, a plurality of electrical circuit elements forming a second electrical circuit element row arranged in a row outside the second ink supply port with respect to the second recording element row, at least a conductive belt-like second recording element protecting section for covering the upper part of the second recording element row, at least a conductive belt-like second electrical circuit element protecting section electrically connected with the second recording element protecting section for covering the upper part of the second electrical circuit element row, a conducting section for electrically connecting the first electrical circuit element protecting section and the second electrical circuit element protecting section to each other, and an inspection electrode pad adapted to be electrically connected to the conducting section.
Embodiments of the invention is explained below with reference to the drawings.
An ink jet recording head H1001 according to this embodiment, as shown in the perspective views of
This recording head cartridge H1000 is fixedly supported by an electrical contact and positioning means of a carriage (not shown) mounted on the ink jet recording apparatus proper on the one hand and removable from the carriage on the other hand. The ink tank H1901 is for black ink, the ink tank H1902 for cyan ink, the ink tank H1903 for magenta ink, and the ink tank H1904 for yellow ink. In this way, the ink tanks H1901 to H1904 are mounted on the side of the seal rubbers H1800 (
Each component part of the recording head H1001 is sequentially explained in more detail.
(1) Recording Head
The recording head H1001 is of bubble-jet side shooter type for performing the recording operation using an electrothermal energy conversion element (recording element) for generating the thermal energy to generate the film boiling of the ink in accordance with an electrical signal.
The recording head H1001, as shown in the exploded perspective view of
The recording element unit H1002, as shown in the exploded perspective view of
(1-1) Recording Element Unit
The first recording element substrate H1100, as shown in the exploded perspective view of
As shown in the exploded perspective view of
The ink supply port H1102 is formed in the shape of a rectangularly grooved through hole by a method such as anisotropic etching or sand blasting utilizing the crystalline orientation of Si.
The first recording element substrate H1100, as shown in the exploded perspective view of
The second recording element substrate H1101, as shown in the exploded perspective view of
The first plate H1200 is formed of, for example, an alumina (Al2O3) material having a thickness of 0.5 mm to 10 mm. However, this first plate H1200 may be formed of any other materials having a coefficient of linear expansion equivalent to that of the material of the first recording element substrate H1100 and a heat conductivity at least equal to that of the material of the first recording element substrate H1100. Also, the first plate H1200 is formed with ink pass holes H1201 for supplying the black ink to the first recording element substrate H1100 on the one hand and supplying the cyan, magenta and yellow ink to the second recording element substrate H1101 on the other. The ink supply ports H1102 of the first and second recording element substrates H1100, H1101 correspond to the ink pass holes H1201, respectively, of the first plate H1200, while the first and second recording element substrates H1100, H1101 are fixedly bonded with high positional accuracy on the first plate H1200.
The electrical wiring tape H1300 is means for applying an electrical signal to discharge the ink to the first recording element substrate H1100 and the second recording element substrate H1101. This electrical wiring tape H1300, as shown in
The electrical wiring tape H1300 is electrically connected with the first recording element substrate H1100 and the second recording element substrate H1101, respectively. The connecting method consists in, for example, the thermal ultrasonic welding process for electrically coupling the bumps H1105 on the electrodes H1104 of the recording element substrates and the electrode lead H1302 of the electrical wiring tape H1300 to each other.
The second plate H1400 is a single tabular member having a thickness of 0.5 mm to 1 mm and is formed of a metal material such as Al or SUS or a ceramic such as alumina. The second plate H1400, however, is not limited to these materials, but may be formed of any other materials having a coefficient of linear expansion equivalent to that of the recording element substrates H1100, H1101 and the first plate H1200 and a heat conductivity at least equal to that of the recording element substrates H1100, H1101 and the first plate H1200.
The second plate H1400 is formed in such a shape as to have a larger opening than the outer dimensions of the first recording element substrate H1100 and the second recording element substrate H1101 fixedly bonded with the first plate H1200. Also, as shown in
The electrically connected portion of the first recording element substrate H1100 and the second recording element substrate H1101 with the electrical wiring tape H1300 is sealed with a first sealing agent (not shown) and a second sealing agent (not shown), so that the electrically connected portion is protected against an external shock and a corrosion by the ink. The first sealing agent is used mainly for sealing the reverse surface of the connecting section between the electrode lead H1302 of the electrical wiring tape and the bumps H1105 of the recording element substrates and the outer peripheral portion of the recording element substrates. The second sealing agent is used for sealing the obverse surface of the connecting section.
An end portion of the electrical wiring tape H1300 is electrically connected, by thermal bonding using an anisotropic conductive film or the like, with an electrical contact substrate H2200 having an external signal input terminal H1301 for receiving an electrical signal from the ink jet recording apparatus proper.
The electrical wiring tape H1300 is bonded to the second plate H1400 while at the same time being bent along one side of the first plate H1200 and the second plate H1400 and bonded to the side surface of the first plate H1200 by the third adhesive layer H1306. The second adhesive forming the second adhesive layer H1203, which is desirably low in viscosity and thus can form a thin second adhesive layer H1203 on the contact surface, has an ink resistance. Also, the third adhesive layer H1306 is a thermoset adhesive layer made of an epoxy resin, for example, as a main component having a thickness of not more than 100 μm.
(1-2) Ink Supply Unit (Recording Liquid Supply Means)
The ink supply member H1500 is formed by resin molding, for example. The resin material is preferably mixed with 5 to 40% of a glass filler to improve the profile toughness.
As shown in
The ink supply member H1500 has the function of holding the ink tank H1900 removably and has a first hole H1503 adapted to engage a second claw H1910 of the ink tank H1900.
The ink supply member H1500 includes a mounting guide H1601 for guiding the recording head cartridge H1000 to the carriage mounting position of the ink jet recording apparatus proper, an engaging section for fixedly mounting the recording head cartridge H1000 on the carriage by a head set lever, an X-direction (carriage scanning direction) butting section H1509 for setting the carriage in a predetermined position, a Y-direction (recording medium conveying direction) butting section H1510 and a Z-direction (ink discharge direction) butting section H1511. Also, the ink supply member H1500 includes a terminal fixing unit H1512 for fixing the electrical contact substrate H2200 of the recording element unit H1002 in position. A plurality of ribs are arranged on and around the terminal fixing unit H1512 to improve the rigidity of the surface having the terminal fixing unit H1512.
(1-3) Coupling Between Recording Head Unit and Ink Supply Unit
As shown in
In order to establish communication between the ink pass hole of the recording element unit H1002 (the ink pass hole H1201 of the first plate H1200) and the ink pass hole of the ink supply unit H1003 (the ink pass hole H1602 of the flow path forming member H1600) in such a manner as not to leak the ink, the respective members are fixed by a screw H2400 through the joint rubber H2300. At the same time, the recording element unit H1002 is accurately fixed in position with respect to the reference positions in X, Y and Z directions of the ink supply unit.
The electrical contact substrate H2200 of the recording element unit H1002 is set in position fixedly on one side surface of the ink supply member H1500 by terminal positioning pins H1516 (at four points) and the terminal positioning holes H1310 (at four points). A method of fixing consists in caulking the terminal positioning pins H1516 of the ink supply member H1500. Nevertheless, another fixing means may be used for fixing. A completion drawing is shown in
A recording head H1001 is completed by fitting and coupling the connecting hole and the connecting section of the ink supply member H1500 on the tank holder H2000. Specifically, the recording head H1001 is configured by coupling, with an adhesive or the like, the ink supply unit H1003 including the ink supply member H1500, the flow path forming member H1600, the filter H1700 and the seal rubber H1800, the recording element unit H1002 including the recording element substrates H1100, H1101, the first plate H1200, the wiring substrate H1300 and the second plate H1400, and the tank holder H2000 to each other. A completion drawing is shown in
(2) Recording Head Cartridge
The ink then is supplied to the bubble chamber including the electrothermal energy conversion elements H1103 and the discharge ports H1107, and discharged toward the recording paper forming a recording medium by the thermal energy applied by the ink to the electrothermal energy conversion elements H1103.
<Embodiment 1>
A first embodiment of this invention is explained below with reference to
As shown in
A method of fabricating the recording element unit H1002 according to this embodiment is explained, step by step, with reference to
First, the second plate H1400 is bonded to the first plate H1200 by second adhesive layers H1203. Next, first adhesive layers H1202 for bonding the first and second recording element substrates H1100, H1101 to the first plate H1200 are formed by being coated on the first plate H1200. After that, the first and second recording element substrates H1100, H1101 are fixedly pressed in relative positions along the wiring plane of a plurality of electrothermal energy conversion elements H1103 or the discharge ports H1107 for discharging the recording liquid.
After that, third adhesive layers H1306 for fixedly bonding the reverse surface of the electrical wiring tape H1300 are formed by being coated on the second plate H1400. Then, the electrodes H1104 of the first and second recording element substrates H1100, H1101 are set in position with the electrode lead H1302 of the electrical wiring tape H1300 and fixedly pressed. After that, the bumps H1105 on the electrodes 1104 of the first and second recording element substrates H1100, H1101 and the electrode leads H1302 of the electrical wiring tape H1300 are electrically coupled with each other, at each one point thereof, by the thermal ultrasonic welding process.
Further, the joints between the bumps H1105 on the electrodes H1104 of the first and second recording element substrates H1100, H1101 and the electrode lead H1302 of the electrical wiring tape H1300 are sealed with resin to prevent the shorting which otherwise might be caused by the ink, etc.
In this embodiment, the first plate H1200 and the second plate H1400 are made of alumina. The electrical wiring tape (flexible printed board) H1300, as described above, has a structure of three layers including a base film, a copper foil wiring and a solder resist, and is provided with the device holes H1, H2 thereby exposing the gold-plated electrode leads H1302.
The second plate H1400 according to this embodiment is a single tabular member provided with two holes into which the first and second recording element substrates H1100, H1101, respectively, are to be inserted. The second plate H1400 is fixedly bonded to the first plate H1200. Also, the electrical wiring tape H1300 is bonded to the second plate H1400 by the third adhesive layers H1306, over the entire surface thereof except for the device holes H1, H2 formed to expose the first and second recording element substrates H1100, H1101.
According to this embodiment, the black head and the color head are both integrally assembled on the same wiring board, and therefore the correction of the landing points of the ink from the two heads is not required.
In the recording head H1001 having the aforementioned configuration according to this embodiment, the black ink is discharged using the first recording element substrate H1100, while the color ink for the three colors including cyan, magenta and yellow is discharged using the second recording element substrate H1101.
The nozzle of the first recording element substrate H1100 is so configured that the discharge ports H1107 are arranged in staggered fashion on the two sides of the ink supply port H1102 each at the rate of 300 dpi. The electrothermal energy conversion elements (recording element) H1103 of 600 dpi are arranged at positions in opposed relation with the respective discharge ports H1107. The second recording element substrate H1101 has three ink supply ports H1102 for each substrate. The discharge ports H1107 for cyan, magenta and yellow are arranged in staggered fashion at intervals of 600 dpi on each side, and the electrothermal energy conversion elements (recording elements) H1103 are arranged at intervals of 1200 dpi at positions in opposed relation with the corresponding discharge ports H1107, respectively. The recording head H1001 according to this embodiment has the two recording element substrates H1100, H1101, for black and color, mounted on the single first plate H1200 in order to secure an arrangement of the two recording element substrates H1100, H1101 with a very high accuracy. Also, the electrical contact substrate H2200 and the electrical wiring tape H1300 for supplying power and data from the ink jet recording apparatus proper are shared by the two recording element substrates H1100, H1101 to reduce the number of parts and the cost at the same time.
The recording head H1001 according to this embodiment is mounted on the carriage of the ink jet recording apparatus proper. An electrical contact on the carriage and the electrical contact substrate H2200 arranged on the recording head H1001 are electrically connected to each other.
A detailed configuration of the two recording element substrates H1100, H1101 constituting the main feature of the invention is explained.
The configuration of the first recording element substrate H1100 is explained with reference to
As shown in
With this configuration, the damage due to the cavitation and the effect of heat at the parts formed with the electrothermal energy conversion elements H1103 and the transistors H1121 can be avoided by the anti-cavitation films H1126, H1127, while at the same time making it possible to secure a sufficient ink resistance of the parts formed with the transistors.
In view of the fact that the ratio which the anti-cavitation films H1126, H1127 occupy of the interior of the Si substrate H1110 is reduced, as shown in
As described above, according to this embodiment, the parts such as the electrothermal energy conversion elements H1103 and the electrical circuit elements H1121 on the first recording element substrate H1110 are protected, while at the same time making it possible to maintain accurate position of the discharge ports H1107 and the flow paths H1130.
According to this embodiment, the first anti-cavitation film H1126 is arranged as shown in
With the conventional recording head, as shown in
According to this embodiment, by contrast, when the alternate ones of the electrothermal energy conversion elements H1103 are displaced by d as shown in
According to this embodiment, whether the protective film H1124 under the anti-cavitation films H1126, H1127 is formed free of defects or not can be inspected by utilizing the single inspection electrode pad H1131 arranged on the anti-cavitation film H1127. In a technique employed for this purpose, test probes (not shown) are brought into contact with the inspection electrode pad H1131 to check for the shorting with all the terminals for operating the circuits of the transistors H1121 and the electrothermal energy conversion elements H1103 in the substrate.
When the protective film H1124 is formed free of defects, Ta of the anti-cavitation films H1126, H1127 is insulated from the internal circuits of the substrate by the protective film H1124. In such a case, upon supply of predetermined power from a drive circuit not shown, an appropriate voltage is applied to the electrothermal energy conversion elements H1103, so that the desired heat generation is obtained for discharging the ink.
When the protective film H1124 has a defect, in contrast, Ta of the anti-cavitation films H1126, H1127 and the internal circuits of the substrate are shorted with each other through the defective portion. When the current between the test probes is measured by bringing the test probes into contact with the inspection electrode pad H1131, therefore, the current value obtained is larger than in the absence of defects, so that an abnormality is detected by the measuring person. In this way, when the protective film H1124 has a defect, the internal circuits of the substrate are shorted with the anti-cavitation films H1126, H1127. Even when a predetermined power is supplied from a drive circuit not shown, therefore, no appropriate voltage is applied to the electrothermal energy conversion elements H1103 and no desired heat can be generated for discharging the ink.
As described above, according to this embodiment, the protective film H1124 can be checked for any defect with only one inspection electrode pad H1131 provided for the anti-cavitation films H1126, H127. Thus, the substrate size can be further reduced unlike the configuration of the recording head disclosed in Japanese Patent Application Laid-Open No. 2002-79672, in which the inspection electrode pad H1131 is provided for each of the anti-cavitation films H126, H1127.
A part of the method of fabricating the recording head H1001 according to this embodiment is described briefly.
As shown in
The foregoing is the description of the first recording element substrate H1100 having a single supply hole H1102 and a pair of discharge port rows on the two sides of the supply hole H1102. Now, the second recording element substrate H1101 is described with reference to
According to this embodiment, the second recording element substrate H1101 includes three supply holes H1102 and a total of six rows of discharge ports including one on each of the two sides of each supply hole H1102. While a pair of rectangular anti-cavitation films H1126, H1127 are formed for the first recording element substrate H1100, therefore, the second recording element substrate H1101 is formed with three pairs of rectangular anti-cavitation films H1126, H1127.
The first anti-cavitation film H1126 covers the upper part of the electrothermal energy conversion elements H1103, while the second anti-cavitation film H1127 covers the upper part of the transistors (electrical circuit elements) H1121. The three pairs of the anti-cavitation films H1126, H1127 are required to be connected and the inspection electrode pad H1131 is required to be arranged in optimum way from the viewpoints of the adhesion between the substrate H1110 and the discharge port forming member H1129 on the one hand and the space of the inspection electrode pad H1131 on the other. Specifically, a pair of the anti-cavitation films H1126, H1127, like the first recording element substrate H1100, are electrically connected to each other by the anti-cavitation film wiring H1140 inside the rectangle of the second anti-cavitation film H1127. Further, the adjoining ones of the second anti-cavitation films H1127 are electrically connected to each other by the anti-cavitation film wiring H1141. Only one inspection electrode pad H1131, like the first recording element substrate H1100, is provided for the central second anti-cavitation film H1127. This inspection electrode pad H1131 is desirably arranged in an area distant from the discharge ports H1107, as shown in
As described above, according to this embodiment, also in the case of the second recording element substrate H1101, the protective film H1124 can be checked for any defect with only one inspection electrode pad H1131 provided for the anti-cavitation films H1126, H1127, thereby making it possible to further reduce the size of the substrate.
<Embodiment 2>
A second embodiment of the invention is explained below with reference to
According to this embodiment, the adjoining ones of the second anti-cavitation films H1127 of the second recording element substrate H1101 are electrically connected to each other by the second anti-cavitation film wiring H1141 (connecting wire). The wiring led out from each of the second anti-cavitation film wirings H1141 is provided with the inspection electrode pads H1131 (two in
The wiring led out of the second anti-cavitation film wiring H1141 is considered to have a negligibly small factor for weakening the adhesion between the substrate H1110 and the discharge port forming member H1129. As a result, the number of the inspection electrode pads H1131 can be increased in order to give priority to the detection sensitivity in an area where the inspection electrode pad H1131 arranged on the lead wiring has no effect on the adhesion between the substrate H1110 and the discharge port forming member H1129 and where the substrate size is not increased.
(3) Ink Jet Recording Apparatus
A recording apparatus on which a recording head H1001 of cartridge type described above can be mounted is explained.
In the recording apparatus shown in
The carriage 102 is supported and guided reciprocably along guide shafts 103 arranged extending on the apparatus proper in the main scanning direction. The carriage 102 is driven by a driving mechanism including a main scanning motor 104 through a motor pulley 105, a driven pulley 106 and a timing belt 107, while at the same time being controlled in position and movement. Also, a home position sensor 130 is mounted on the carriage 102. As a result, it is possible to determine the position at which the home position sensor 130 on the carriage 102 passes the masking plate 136.
The recording medium 108 such as the printing papers and the plastic sheets are fed, separately one by one, from an auto sheet feeder (ASF) 132 by rotating pickup rollers 131 by a paper feed motor 135 through a gear. Further, the rotation of a conveyor roller 109 causes the recording medium 108 to be conveyed (auxiliary scanning) through a position (print unit) in opposed relation with the discharge port surface of the recording head cartridge H1000. The conveyor roller 109 is driven by the turning effort of a LF motor 134 through a gear. In the process, it is determined whether the paper has been fed or not and the starting position of paper feed is searched and determined at the time point when the recording medium 108 passes a paper end sensor 133. The paper end sensor 133 is used also for the purpose of determining the actual position of the rear end of the recording medium 108 and finally determining the current recording position from the actual rear end.
The recording medium 108 has the reverse side thereof supported by a platen (not shown) in order to form a flat printed surface at the printing unit. In this case, the recording head cartridge H1000 mounted on the carriage 102 is held in such a manner that the discharge port surface thereof is projected downward of the carriage 102 in parallel to the recording medium 108 between the pair of the conveyor rollers.
The recording head cartridge H1000 is mounted on the carriage 102 in such a manner that the discharge ports of the discharge units are arranged in the direction crossing the scanning direction of the carriage 102. The recording liquid is discharged from these discharge ports for recording.
It will thus be understood from the foregoing description that according to the embodiments of the invention, there are provided a reliable, compact recording head and a recording apparatus using the recording head, in which the adhesion between a compact substrate and a discharge port forming member is improved, while having a sufficient ink resistance and a sufficient anti-cavitation property, and in which the protective film capable of preventing the damage to the circuits in the substrates can be easily inspected for a defect.
Number | Date | Country | Kind |
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2002-211740 | Jul 2002 | JP | national |
Number | Name | Date | Kind |
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6374482 | Mihara et al. | Apr 2002 | B1 |
6402297 | Yamaguchi | Jun 2002 | B1 |
6402302 | Ozaki et al. | Jun 2002 | B1 |
6443563 | Saito et al. | Sep 2002 | B1 |
6474790 | Kaneko | Nov 2002 | B2 |
6485132 | Hiroki et al. | Nov 2002 | B1 |
6513911 | Ozaki et al. | Feb 2003 | B1 |
6578951 | Ozaki et al. | Jun 2003 | B2 |
20020084245 | Hiroki et al. | Jul 2002 | A1 |
Number | Date | Country |
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2002-79672 | Mar 2002 | JP |
Number | Date | Country | |
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20040012654 A1 | Jan 2004 | US |