1. A developer conveying apparatus comprising:
a developer reservoir for storing liquid developer;
a conveying member arranged in the developer reservoir to convey liquid developer by rotating around the axis thereof; and
a hollow path containing the conveying member in the inside thereof and guiding the liquid developer being conveyed by the conveying member.
2. The apparatus according to claim 1, wherein
the developer reservoir includes a reservoir base section having a recess and a conveying base section having the hollow path arranged therein.
3. The apparatus according to claim 2, wherein,
when the radius of the outer periphery of the conveying member is r1 and the radius of a conveying port is r2, while the radius of curvature of the recess is r3, they show a relationship of r1<r2<r3.
4. The apparatus according to claim 1, wherein
the conveying member is a screw.
5. The apparatus according to claim 1, wherein
the conveying member has a spiral blade.
6. The apparatus according to claim 1, wherein
a spring member is contained in the hollow path and connected to an end of the conveying member.
7. An image forming apparatus comprising:
a roller for holding liquid developer;
a roller cleaning blade adapted to be brought into contact with the roller and scrape off the liquid developer held by the roller; and
a developer conveying apparatus including:
a developer reservoir for receiving the liquid developer scraped off by the roller cleaning blade;
a conveying member arranged in the developer reservoir to convey liquid developer by rotating around the axis thereof; and
a hollow path containing the conveying member in the inside thereof and guiding the liquid developer being conveyed by the conveying member.
8. The apparatus according to claim 7, wherein
the roller is a developing roller.
9. The apparatus according to claim 7, wherein
the roller is an image carrier squeezing roller held in contact with an image carrier.
10. The apparatus according to claim 7, wherein
the conveying member is a screw.
11. The apparatus according to claim 10, wherein
the blade winding pitch of the screw for conveying the liquid developer scraped off from the image carrier and the blade winding pitch of the screw for conveying the liquid developer scraped off from the developing roller are different from each other.
12. The apparatus according to claim 10, wherein
the number of revolutions per unit time of the screw for conveying the liquid developer scraped off from the image carrier and the number of revolutions per unit time of the screw for conveying the liquid developer scraped off from the developing roller are different from each other.
13. The apparatus according to claim 7, wherein
a plurality of developer reservoirs are provided.
14. The apparatus according to claim 7, wherein
the developer reservoir includes a reservoir base section having a recess and a conveying base section connected to the hollow path.
15. The apparatus according to claim 7, wherein
a spring member substantially contained in the hollow path is connected to an end of the conveying member.
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 method for shifting the optical frequency of light from an input frequency to at least two shifted frequencies, comprising:
in a first nonlinear optical device having a reference frequency F1, shifting at least some of the power of a light beam from the input frequency to a first shifted frequency situated in the electromagnetic spectrum such that F1 lies midway between the input frequency and the first shifted frequency; and
in a second nonlinear optical device having a reference frequency F2, shifting at least some of said power from the first shifted frequency to a second shifted frequency situated in the electromagnetic spectrum such that F2 lies midway between the first and second shifted frequencies and a difference of 2(F2\u2212F1) separates the second shifted frequency from the input frequency.
2. The method of claim 1, further comprising optically filtering the light output from the first said device prior to entry of the light into the second said device, thereby to reduce the amount of input-frequency light that enters the second said device.
3. The method of claim 1, further comprising returning at least some of the light output from the second said device and passing it at least one more time through at least the first said device.
4. The method of claim 1, further comprising cycling light in multiple passes through said first and second devices.
5. The method of claim 4, further comprising amplifying the light between each successive pair of said multiple passes.
6. The method of claim 4, further comprising extracting a portion of the light from each of said multiple passes, thereby to obtain a frequency comb of output light.
7. The method of claim 4, further comprising at least two steps of optical filtering on each said pass, wherein:
one filtering step, to be referred to as frequency high-pass filtering, reduces the amount of light having frequencies less than at least the smaller of F1 and F2; and
another filtering step, to be referred to as frequency low-pass filtering, reduces the amount of light having frequencies greater than at most the larger of F1 and F2.
8. The method of claim 7, wherein the frequency high-pass filtering is carried out so as to reduce the amount of light having frequencies less than the larger of F1 and F2.
9. The method of claim 7, wherein the frequency low-pass filtering is carried out so as to reduce the amount of light having frequencies greater than the smaller of F1 and F2.
10. The method of claim 7, wherein:
the high-pass filtering is carried out so as to directly affect light entering the device having the higher reference frequency; and
the low-pass filtering is carried out so as to directly affect light entering the device having the lower reference frequency.
11. The method of claim 7, wherein:
the high-pass filtering is carried out so as to directly affect light entering the device having the lower reference frequency; and
the low-pass filtering is carried out so as to directly affect light entering the device having the higher reference frequency.
12. Apparatus, comprising:
at least first and second nonlinear optical devices, each having an input, an output, and a reference frequency; and
an exit optical medium for extraction therethrough of at least some light after passing at least once through each of the first and second said devices, wherein:
each of said first and second devices is effective for shifting at least some of the power of a light beam from an initial frequency applied to its input to a shifted frequency situated in the electromagnetic spectrum such that the pertinent reference frequency lies midway between the initial frequency and the shifted frequency;
the first device has reference frequency F1 and the second device has reference frequency F2 which is different from F1; and
the input to the second said device is optically coupled to the output of the first said device, such that in combination, the first and second devices are effective for shifting at least some of the power in an input beam applied to the input of the first device from an input frequency to a twice-shifted output frequency separated from the input frequency by 2(F2\u2212F1).
13. The apparatus of claim 12, further comprising an optical filter arranged to reduce the power, at the input frequency, of light exiting the first device prior to entry of said light into the second device.
14. The apparatus of claim 12, further comprising an optical path that couples the output of the second device to the input of the first device, such that light can be cycled in multiple passes through said first and second devices.
15. The apparatus of claim 14, further comprising an optical amplifier in the optical path.
16. The apparatus of claim 14, further comprising an optical coupling element in the optical path, said coupling element arranged to extract a portion of the light cycling in the optical path from the optical path into the exit optical medium.
17. The apparatus of claim 14, further comprising:
an optical filter situated so as to directly affect light entering the device having the higher reference frequency, and
a further optical filter situated so as to directly affect light entering the device having the lower reference frequency,
wherein one of said filters is effective for reducing the amount of light having frequencies greater than at most the larger of F1 and F2, and the other of said filters is effective for reducing the amount of light having frequencies less than at least the smaller of F1 and F2.
18. The apparatus of claim 14, further comprising:
an optical filter situated so as to directly affect light entering the device having the higher reference frequency, said filter effective for reducing the amount of light having frequencies less than the larger of F1 and F2; and
an optical filter situated so as to directly affect light entering the device having the lower reference frequency, said filter effective for reducing the amount of light having frequencies greater than the smaller of F1 and F2.
19. The apparatus of claim 14, further comprising:
an optical filter situated so as to directly affect light entering the device having the lower reference frequency, said filter effective for reducing the amount of light having frequencies less than the larger of F1 and F2; and
an optical filter situated so as to directly affect light entering the device having the higher reference frequency, said filter effective for reducing the amount of light having frequencies greater than the smaller of F1 and F2.
20. The apparatus of claim 14, further comprising a tunable filter optically coupled to the exit optical medium and effective, in response to a control signal, for selecting between individual optical frequencies of light extracted from the optical path.
21. The apparatus of claim 14, further comprising:
a frequency demultiplexer having an input optically coupled to the exit optical medium and having multiple outputs, each corresponding to a distinct frequency channel;
a frequency multiplexer having multiple inputs, each corresponding to a distinct frequency channel, and having an output;
two or more modulators, each optically coupled between an output of the demultiplexer and an input of the multiplexer; and
an output waveguide optically coupled to the output of the multiplexer.
22. The apparatus of claim 12, wherein each of the first and second nonlinear optical devices comprises a PPLN device.
23. The apparatus of claim 22, wherein each of the first and second nonlinear optical devices further comprises a pump laser having an output optically coupled to the pertinent PPLN device.