1. A liquid ejection head, comprising:
a plurality of ejection ports which eject liquid;
a plurality of pressure chambers which are communicated with the ejection ports;
a plurality of piezoelectric elements which are arranged to sides of the pressure chambers opposite sides of the pressure chambers where the ejection ports are formed, the piezoelectric elements each having driving electrodes, the piezoelectric elements each deforming the pressure chambers when drive signals are applied through the driving electrodes;
a protective member which covers the piezoelectric elements and has a first wiring layer electrically connected to a first external wiring;
a common liquid chamber which is arranged on the protective member on the sides of the plurality of pressure chambers opposite the sides of the pressure chambers where the ejection ports are formed, a wall of the common liquid chamber opposite the protective member having a second wiring layer electrically connected to a second external wiring, the common liquid chamber supplying the liquid to the plurality of pressure chambers; and
a plurality of wiring members which are electrically connected to the second wiring layer and formed so that at least a part of each of the wiring members extends inside the common liquid chamber in a direction substantially perpendicular to a surface on which the piezoelectric elements are arranged,
wherein a part of the driving electrodes of the piezoelectric elements are electrically connected to the first wiring layer, and another part of the driving electrodes of the piezoelectric elements are electrically connected to the second wiring layer through the wiring members.
2. The liquid ejection head as defined in claim 1, wherein the protective member is configured by overlapping a multilayer wired green sheet and a green sheet having recesses for covering the piezoelectric elements.
3. The liquid ejection head as defined in claim 1, wherein the protective member is configured by overlapping a wiring layer and an insulating layer on a silicon substrate, and has recesses for covering the piezoelectric elements formed on a side of the silicon substrate opposite the wiring layer.
4. The liquid ejection head as defined in claim 1, wherein the protective member is configured by overlapping an insulating layer and a wiring layer formed by a selective droplet ejection device on a rigid substrate, and has recesses for covering the piezoelectric elements formed on a side of the rigid substrate opposite the wiring layer.
5. The liquid ejection head as defined in claim 1, wherein a thickness from the side of the pressure chamber on the piezoelectric element to the side of the protective member on the common liquid chamber is not less than 100 \u03bcm and not more than 200 \u03bcm.
6. The liquid ejection head as defined in claim 1, further comprising:
a plurality of pressure sensors which detect pressure fluctuations in the pressure chambers,
wherein all the driving electrodes of the piezoelectric elements are electrically connected to one of the first wiring layer and the second wiring layer, and all the detecting electrodes of the pressure sensors are electrically connected to the other of the first wiring layer and the second wiring layer.
7. The liquid ejection head as defined in claim 1, wherein the wiring members are formed so as to extend from the piezoelectric elements.
8. The liquid ejection head as defined in claim 1, wherein the wiring members are formed so as to extend from vicinity of the piezoelectric elements.
9. The liquid ejection head as defined in claim 1, wherein:
the ejection ports are two-dimensionally arrayed; and
the wiring members are two-dimensionally arrayed with respect to the surface on which the piezoelectric elements are arranged.
10. An image forming apparatus, comprising the liquid ejection head as defined in claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A device for estimating a first resistance of a ground connection for an electrical apparatus when the electrical apparatus is connected to a power supply system and is also connected to the ground by a second resistance, the electrical apparatus including at least one input impedance, the estimating device comprising:
a voltage generator including means for connecting to the input impedance and means for connecting to the ground connection;
means for measuring current flowing to the ground through the first resistance of the ground connection when the means for connecting to the input impedance and to the ground connection are activated; and
calculating means configured to obtain an order of magnitude for the first resistance of the ground connection, as a function of the current flowing to the ground, the obtained order of magnitude being with respect to a value of the second resistance.
2. The device as claimed in claim 1, further comprising means for measuring leakage current from a differential supply current for the electrical apparatus, and wherein the calculating means is configured to estimate an additional resistance as a function of the leakage current and of the current flowing to the ground.
3. The device as claimed in claim 2, wherein the calculating means comprises a table including resistance values for the ground connection, values of additional resistance, and values of current flowing to the ground corresponding to the resistance values for the ground connection and to values of the additional resistance.
4. The device as claimed in claim 1, wherein the input impedance is an input impedance of an electromagnetic compatibility filter.
5. The device as claimed in claim 1, wherein the voltage generator is a voltage-controlled oscillator.
6. The device as claimed in claim 1, further comprising means for prohibiting use of the electrical apparatus as a function of the order of magnitude of the first resistance of the ground connection.
7. The device as claimed in claim 1, wherein the electrical apparatus is a battery charger for an electric or hybrid traction motor vehicle.
8. A method for estimating a first resistance of a ground connection for an electrical apparatus when the electrical apparatus is connected to a power supply system and is also connected to the ground by a second resistance, the estimation method comprising:
generating a current between an input impedance of the electrical apparatus and the first resistance of the ground connection;
measuring current flowing to the ground through the first resistance of the ground connection to obtain an order of magnitude for the resistance of the ground connection with respect to a value of the additional resistance; and
calculating an order of magnitude for the first resistance of the ground connection, as a function of the current flowing to the ground, the calculated order of magnitude being with respect to a value of the second resistance.
9. The method as claimed in claim 8, further comprising measuring a leakage current from a differential power supply current, and the second resistance is estimated as a function of the leakage current and of the current flowing to the ground.
10. The method as claimed in claim 9, wherein the first resistance of the ground connection and the second resistance are estimated by a table having resistance values for the ground connection, values of additional resistance, and values of current flowing to the ground corresponding to the resistance values for the ground connection and to values of the additional resistance.
11. The method as claimed in claim 8, wherein a sinusoidal current is generated through the first resistance of the ground connection.
12. The method as claimed in claim 8, wherein use of the electrical apparatus is prohibited as a function of the order of magnitude of the first resistance of the ground connection.
13. The method as claimed in claim 12, wherein use of the electrical apparatus is prohibited if the first resistance of the ground connection is higher than the second resistance.
14. A device for estimating a first resistance of a ground connection for an electrical apparatus when the electrical apparatus is connected to a power supply system and is also connected to the ground by a second resistance, the electrical apparatus including at least one input impedance, the estimating device comprising:
a voltage generator connected to the input impedance and connected to the ground connection;
circuitry configured to measure current flowing to the ground through the first resistance of the ground connection; and
processing circuitry configured to calculate an order of magnitude for the first resistance of the ground connection, as a function of the current flowing to the ground, the calculated order of magnitude being with respect to a value of the second resistance.