Abstract: An optical semiconductor element includes a ring modulator, and a light absorbing material provided at a position apart from a path for a modulated light which is guided by the ring modulator, the light absorbing material absorbing a light leaked out of a ring waveguide of the ring modulator, and increasing a temperature of the ring waveguide.

Abstract: An optical semiconductor element includes a ring modulator, and a light absorbing material provided at a position apart from a path for a modulated light which is guided by the ring modulator, the light absorbing material absorbing a light leaked out of a ring waveguide of the ring modulator, and increasing a temperature of the ring waveguide.

Abstract: An optical semiconductor element includes a ring modulator, and a light absorbing material provided at a position apart from a path for a modulated light which is guided by the ring modulator, the light absorbing material absorbing a light leaked out of a ring waveguide of the ring modulator, and increasing a temperature of the ring waveguide.

Abstract: An inkjet image forming apparatus includes inkjet heads each of which has two or more nozzle rows from which ink of different colors is injected (each of the nozzle rows includes nozzle holes), a wipe unit that includes wipers and carries out a wipe process to wipe away ink remained on a surface on which the nozzle rows are formed by the wipers, and a flush unit that carries out a flush process after the wipe process by injecting ink from nozzle holes into which ink of different color from color of ink that is injected from the nozzle holes flows during the wipe process. According to the apparatus, an amount of ink consumed in the flush process can be reduced and a replacement cycle of a mist-absorbing material for absorbing ink mists generated during the flush process can be prolonged.

Abstract: A modulated light source includes: a reflective film which is formed at one end of an optical amplifier; a light wavelength filter which has band-pass characteristics and modulates a transmission center wavelength; a light reflection mechanism which feeds back light having passed through the light wavelength filter to the optical amplifier and an optical resonator is formed between which and the reflective film; and a wavelength adjustment mechanism which adjusts the transmission center wavelength to coincide with a specific oscillation wavelength when light oscillation selectively occurs at the specific oscillation wavelength depending on the band-pass characteristics of the light wavelength filter.

Abstract: A processor acquires elapsed time information held by an ink cartridge loaded in an ink cartridge attachment unit, calculates current ink physical property information based on the acquired elapsed time information, and controls an ink ejection operation by an ink-jet head based on the calculated physical property information.

Abstract: A modulated light source includes an FP laser that emits light in a plurality of Fabry-Perot (FP) modes, a band-pass filter whose center wavelength can be modulated, a light reflector that selectively feeds only light having passed through the modulation filter back to the FP laser, and a wavelength adjustment mechanism that adjusts the center wavelength so as to coincide with one of the predetermined FP mode when the light fed back to the FP laser is used as seed light for stimulated emission of radiation to cause selective light emission at an oscillation wavelength.

Abstract: Upon supply of inks to second tanks of a plurality of printing units with the second tanks in communication with each other via a negative-pressure common air chamber in an air-tight state and with a negative-pressure force applied to the second tanks and the negative-pressure common air chamber, a controller is configured to drive ink supply units of the plurality of printing units to supply the inks such that times in which the inks flow into the second tanks in the plurality of printing units do not coincide with each other.

Abstract: A controller, upon a pressure of one tank of a positive pressure tank and a negative pressure tank reaching a setting pressure of the one tank prior to a pressure of the other tank reaching a setting pressure of the other tank after driving an air pump, sets an air opening valve opening time at each unit time according to a difference between the pressure of the one tank and the pressure of the other tank, and repeatedly drives one of a positive-pressure-side air opening valve and a negative-pressure-side air opening valve corresponding to the one tank to switch to and hold an air open state of the one tank for the set air opening valve opening time within the unit time, until the pressure of the other tank reaches the setting pressure of the other tank.

Abstract: A controller regulates pressures of a positive pressure space and a negative pressure space and maintains the pressures at setting pressures when ink is circulated in a circulation path, by: driving an air pump to apply the setting pressures to the positive pressure space and the negative pressure space; and after the setting pressures are applied, controlling opening and closing of a positive-pressure-side pressure regulation valve, opening and closing of a negative-pressure-side pressure regulation valve, and driving of the air pump according to the pressures in the positive pressure space and the negative pressure space, and opening the positive-pressure-side pressure regulation valve or the negative-pressure-side pressure regulation valve simultaneously with the driving of the air pump.

Abstract: A controller, upon a pressure of one tank of a positive pressure tank and a negative pressure tank reaching a setting pressure of the one tank prior to a pressure of the other tank reaching a setting pressure of the other tank after driving an air pump, sets an air opening valve opening time at each unit time according to a difference between the pressure of the one tank and the pressure of the other tank, and repeatedly drives one of a positive-pressure-side air opening valve and a negative-pressure-side air opening valve corresponding to the one tank to switch to and hold an air open state of the one tank for the set air opening valve opening time within the unit time, until the pressure of the other tank reaches the setting pressure of the other tank.

Abstract: An ink temperature adjustment device and an inkjet printer include an ink temperature adjustment path connected to a midway point on an ink supply path for supplying ink to an inkjet head configured to form an image by ejecting the ink. The ink temperature adjustment path is for adjusting a temperature of the ink supplied to the inkjet head. The ink temperature adjustment path includes an upflow path for the ink to flow upward and a downflow path for the ink to flow downward. A total cross-sectional area of the upflow path is larger than a total cross-sectional area of the downflow path.

Abstract: A controller regulates pressures of a positive pressure space and a negative pressure space and maintains the pressures at setting pressures when ink is circulated in a circulation path, by: driving an air pump to apply the setting pressures to the positive pressure space and the negative pressure space; and after the setting pressures are applied, controlling opening and closing of a positive-pressure-side pressure regulation valve, opening and closing of a negative-pressure-side pressure regulation valve, and driving of the air pump according to the pressures in the positive pressure space and the negative pressure space, and opening the positive-pressure-side pressure regulation valve or the negative-pressure-side pressure regulation valve simultaneously with the driving of the air pump.

Abstract: An optical semiconductor device includes a ring waveguide, and a serpentine waveguide configured to be optically connected to the ring waveguide and surround at least a part of the ring waveguide in a serpentine form. In the optical semiconductor device, the serpentine waveguide heats the ring waveguide by absorbing input light propagated from the ring waveguide to the serpentine waveguide.

Abstract: An inkjet image forming apparatus includes inkjet heads each of which has two or more nozzle rows from which ink of different colors is injected (each of the nozzle rows includes nozzle holes), a wipe unit that includes wipers and carries out a wipe process to wipe away ink remained on a surface on which the nozzle rows are formed by the wipers, and a flush unit that carries out a flush process after the wipe process by injecting ink from nozzle holes into which ink of different color from color of ink that is injected from the nozzle holes flows during the wipe process. According to the apparatus, an amount of ink consumed in the flush process can be reduced and a replacement cycle of a mist-absorbing material for absorbing ink mists generated during the flush process can be prolonged.

Abstract: An apparatus includes an optical semiconductor element comprising: a waveguide into which input light is input; a plurality of ring modulators that have different optical perimeter lengths and are optically coupled to the waveguide; and a control unit configured to selectively apply a modulation signal to at least one of the plurality of ring modulators having a resonant wavelength that is the same as a wavelength of the input light.

Abstract: An optical semiconductor device includes a waveguide that an input light to be inputted, a ring modulator optically coupled with the waveguide, a first ring resonator optically coupled with the waveguide and having an optical path length smaller than an optical path length of the ring modulator, a second ring resonator optically coupled with the first waveguide and having an optical path length larger than the optical path length of the ring modulator, a heater arranged adjacent to the ring modulator, the first ring resonator and the second ring resonator, a first photodetector monitoring a light power in the first ring resonator, a second photodetector monitoring a light power in the second ring resonator, and a controller controlling the heater so that a resonance wavelength of the ring modulator agrees with a wavelength of the input light, based on signals detected by the first and second photodetectors.

Abstract: Upon supply of inks to second tanks of a plurality of printing units with the second tanks in communication with each other via a negative-pressure common air chamber in an air-tight state and with a negative-pressure force applied to the second tanks and the negative-pressure common air chamber, a controller is configured to drive ink supply units of the plurality of printing units to supply the inks such that times in which the inks flow into the second tanks in the plurality of printing units do not coincide with each other.

Abstract: An optical semiconductor device includes a ring laser including a ring resonator in which an optical gain element having an optical gain by current injection is provided, a waveguide optically coupled to the ring laser, and a reflector provided at an end portion of the waveguide and configured to reverse the advancing direction of light outputted from the ring laser and propagating in the waveguide.

Abstract: A modulated light source includes: a reflective film which is formed at one end of an optical amplifier; a light wavelength filter which has band-pass characteristics and modulates a transmission center wavelength; a light reflection mechanism which feeds back light having passed through the light wavelength filter to the optical amplifier and an optical resonator is formed between which and the reflective film; and a wavelength adjustment mechanism which adjusts the transmission center wavelength to coincide with a specific oscillation wavelength when light oscillation selectively occurs at the specific oscillation wavelength depending on the band-pass characteristics of the light wavelength filter.