1. An apparatus to compensate for mixer offset of signals, comprising:
a mixer receiving a signal at a first input and a second input, and outputting the signal with an offset having a sign at an output;
a detector connected to said output of said mixer and having an output, said output of said detector having the sign of the offset applied thereto;
an actuator unit for generating an offset compensation value to be supplied with the sign of the offset and coupled to said mixer; and
a control unit connected to said actuator unit for controlling the generation of the offset compensation value.
2. The apparatus according to claim 1, wherein said detector is a phase detector.
3. The apparatus according to claim 2, wherein said phase detector has a first and a second amplifier, each with a respective output, a further mixer connected to said outputs of said first and said second amplifier, and a low-pass filter connected downstream of said further mixer.
4. The apparatus according to claim 3, wherein said further mixer is a Gilbert multiplier.
5. The apparatus according to claim 1, wherein said actuator unit has a register and a digitalanalog converter connected to said register.
6. The apparatus according to claim 5, wherein said actuator unit has switchable current sources.
7. The apparatus according to claim 5, wherein said actuator unit has switchable voltage sources.
8. A method to compensate for an offset of the mixer, which comprises the following steps:
determining a sign of a direct voltage offset of a mixer by comparing a signal at an input of the mixer with a signal derived at an output of the mixer;
incrementally setting bits in an actuator unit beginning with a most significant bit;
forming an offset compensation value in the actuator unit, and supplying the offset compensation value to the mixer;
retracting the most recently set bit if a change the of sign in the direct voltage offset of the mixer occurred in the incrementally-setting step; and
retaining the most recently set bit if no change of the sign in the direct voltage offset of the mixer occurred.
9. The method according to claim 8, which further comprises deriving the sign of the direct voltage offset by comparing phase relationships of the signal at the output of the mixer and the signal at the input of the mixer.
10. The method according to claim 9, which further comprises:
setting the sign of the direct voltage offset of the mixer equal to 1 if phase relationships of the signals have a difference of 0\xb0; and
setting the sign of the direct voltage offset of the mixer equal to \u22121 if the difference between the phase relationships of the signals is 180\xb0.
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 liquid supplying apparatus configured to supply liquid to a liquid ejection head capable of ejecting liquid, the liquid supplying apparatus comprising:
a liquid container configured to contain liquid therein;
a filter chamber that is divided into a first filter chamber and a second filter chamber via a filter;
a first supply path configured to allow the first filter chamber and the liquid container to communicate with each other;
a second supply path configured to allow the second filter chamber and the liquid ejection head to communicate with each other;
a bypass path configured to allow the first filter chamber and the liquid container to communicate with each other;
a pump configured to circulate the liquid through the first supply path and the bypass path between the liquid container and the first filter chamber; and
a valve capable of regulating the flow of the liquid in the second supply path.
2. The liquid supplying apparatus according to claim 1, wherein the pump is a pressurizing pump configured to press-feed the liquid contained in the liquid container to the first filter chamber through the first supply path.
3. The liquid supplying apparatus according to claim 1, wherein the pump is a suction pump configured to suck the liquid staying in the first filter chamber, and then, feed the liquid into the liquid container through the bypass path.
4. The liquid supplying apparatus according to claim 1, wherein the valve regulates the flow of the liquid in the second supply path in a case where the liquid is circulated between the liquid container and the first filter chamber by the pump.
5. The liquid supplying apparatus according to claim 4, wherein the valve regulates the flow of the liquid in the second supply path by a pressure of the liquid in a case where the liquid is circulated between the liquid container and the first filter chamber.
6. The liquid supplying apparatus according to claim 5, wherein the valve comprises: a first chamber communicating with the second filter chamber via the second supply path; a second chamber communicating with the liquid ejection head via the second supply path; a communication path configured to allow the first chamber and the second chamber to communicate with each other; and a valve body configured to open or close the communication path according to a difference in pressure between the first chamber and the second chamber.
7. The liquid supplying apparatus according to claim 6, wherein the valve further comprises: a flexible member configured to be displaced according to the difference in pressure between the first chamber and the second chamber; a transmitting unit configured to transmit the displacement of the flexible member to the valve body; and an urging member configured to urge the valve body in a direction in which the communication path is closed.
8. A liquid ejecting apparatus comprising:
the liquid supplying apparatus according to claim 1; and
a liquid ejection head capable of ejecting liquid to be supplied from the liquid supplying apparatus.
9. An inkjet printing apparatus comprising:
the liquid supplying apparatus according to claim 1, the liquid supplying apparatus supplying ink as liquid;
an inkjet printing head configured to eject the ink to be supplied from the liquid supplying apparatus; and
a moving unit configured to relatively move the inkjet printing head and a print medium.
10. A liquid supplying method of supplying liquid contained in a liquid container to a liquid ejection head by using a filter chamber divided into a first filter chamber and a second filter chamber via a filter, the liquid being supplied from the liquid container to the liquid ejection head through the first filter chamber, the filter, and the second filter chamber the liquid supplying method comprising the step of:
regulating the flow of the liquid between the second filter chamber and the liquid ejection head in a case where the liquid is circulated between the liquid container and the first filter chamber.
11. The liquid supplying method according to claim 10, further comprising the step of circulating the liquid between the liquid container and the first filter chamber so as to introduce an air bubble residing in the first filter chamber into the liquid container, thus purging the air bubble.
12. A liquid supplying apparatus configured to supply liquid to a liquid ejection head capable of ejecting liquid, the liquid supplying apparatus comprising:
a liquid container configured to contain liquid therein;
a filter chamber that is divided into a first filter chamber and a second filter chamber via a filter;
a first supply path configured to allow the first filter chamber and the liquid container to communicate with each other;
a second supply path configured to allow the second filter chamber and the liquid ejection head to communicate with each other;
a third supply path configured to allow the first filter chamber and the liquid container to communicate with each other;
a pressurizing pump provided on the first supply path and configured to press-feed the liquid contained in the liquid container to the first filter chamber; and
a valve provided on the second supply path, the valve comprising: a first chamber communicating with the second filter chamber via the second supply path; a second chamber communicating with the liquid ejection head via the second supply path; a communication path allowing the first chamber and the second chamber to communicate with each other; and a valve body capable of opening or closing the communication path, the valve body acting in a direction in which the communication path is closed according to an increase in pressure inside of the first chamber.
13. The liquid supplying apparatus according to claim 12, wherein a part of the second chamber of the valve includes a flexible film.
14. The liquid supplying apparatus according to claim 12, wherein a resilient member is provided inside of the first chamber of the valve.
15. The liquid supplying apparatus according to claim 14, wherein the resilient member is urged in a direction in which the communication path is closed.