Hitachi, Ltd.

Nippon Kayaku Kabushiki Kaisha

Hitachi-lg Data Storage, Inc.

Mariko Umeda

Hiroyuki Minemura

Shigeru Nakamura

Takeshi Shimano

Harukazu Miyamoto

Motoyuki Suzuki

Akira Arimoto

Takeshi Nakao

Yoshiki Akatani

Tetsuo Ariyoshi

Takeshi Maeda

Yuji Suzuki

Hisataka Sugiyama

Takahiro Kurokawa

Yasuo Shirasaki

Kiyoshi Matsumoto

Masuo Kasai

Katsunori Fujii

Eiichi Ogawa

Shinsuke Shimizu

Tadahiko Tabe

Yoshiyuki Dejima

Hideshiro Nomura

Disclosed is a reactive dye ink exhibiting excellent ejection stability when used in a printer having an inkjet head for commercial use which requires a high-viscosity ink. The reactive dye ink has excellent storage stability and excellent fixability to textiles. Specifically disclosed is an ink composition containing at least one reactive dye serving as a coloring matter, which also contains water and a compound represented by formula (1) and having an average molecular weight of 340-2,200. (1) [In the formula, X, X, Xand Xindependently represent a hydrogen atom or a methyl group; and the sum of j, k, m and n is a number not less than 4 but not more than 40.]

Ink composition and textile printing method using the same

A tracking offset is reduced. The effect of an SPP signal fluctuation is reduced by using a variable mixing ratio DPP method, and a residual tracking offset is minimized.

Optical disk apparatus and tracking method

The amount of focus offset and the amount of spherical aberration correction are adjusted with respect to a disk on which no data is recorded with high precision. The amount of focus offset and the amount of spherical aberration correction are adjusted on the basis of (1) a focus error signal amplitude, (2) a tracking error signal amplitude in a wide track pitch region, and (3) a rectangular waveform wobble signal envelop level.

Information recording/reproducing method and information recording/reproducing apparatus

The present invention relates to an aqueous dispersion of a water-insoluble coloring material having superior shelf life stability which is suitable to an ink for ink-jetting, an ink composition superior in shelf life stability and discharge property, a method for inkjet recording using said ink composition, and recorded article obtained thereby. Said aqueous dispersion is characterized by comprising a water-insoluble coloring material, water, an anionic dispersing agent, and an alkylene oxide adduct of phytosterols and/or an alkylene oxide adduct of cholestanols, and said ink composition is characterized by further comprising an organic solvent in addition to the above components.

Aqueous dispersion, ink composition and inkjet recording method using same

A recording method and apparatus reduces jitter and increases the number of possible rewrites in an optical disc. When the absolute values of DSV values calculated for different DCC bits are equal, the selection of the DCC bit is carried out in a random manner, so that a different signal is recorded in each case on an optical disc medium even when the same user data is recorded. As a result, the deterioration of the marks and spaces is made uniform and the number of possible rewrites is increased.

Recording method and recording apparatus

To stably carry out recording and reproducing to and from a high density optical disk without using a double servo in the optical disk using a high NA objective lens. A detection of a spherical aberration and a detection of a coma aberration in a radial direction are simultaneously performed, and the coma aberration generated with the offset of an objective lensis corrected in real time, thus enlarging an allowable offset amount of the objective lens. In order to simultaneously detect the spherical aberration and the coma aberration, focal shift and tracking shift signals in an inside region and outside region of reflected light flux are detected respectively, and the differential signals are set as spherical aberration and coma aberration signals.

Optical head and optical disk apparatus

To stably carry out recording and reproducing to and from a high density optical disk without using a double servo in the optical disk using a high NA objective lens. A detection of a spherical aberration and a detection of a coma aberration in a radial direction are simultaneously performed, and the coma aberration generated with the offset of an objective lens is corrected in real time, thus enlarging an allowable offset amount of the objective lens. In order to simultaneously detect the spherical aberration and the coma aberration, focal shift and tracking shift signals in an inside region and outside region of reflected light flux are detected respectively, and the differential signals are set as spherical aberration and coma aberration signals.

Formazane compounds and method of dyeing using the same

An optical disk device having a light source for emitting light, focusing optics for radiating and focusing the light onto an optical recording medium, a photo-detection system for photoelectrically transforming reflected light from the optical recording medium, a reproduction circuit for reproducing information recorded on the optical recording medium by using an electric signal from the photo-detection system, phase control optics for changing the phase of the reflected light, a readout control circuit for controlling the quantity of the phase change of the phase control optics, and a learning control circuit for calculating the optimum value of the phase change quantity by monitoring the output signal of the reproduction circuit while changing the quantity of the phase change by the readout control circuit. Thus, information can be reproduced from a recording medium having high recording density without crosstalk.

Optical disk device having optical phase compensator

A focus error detecting method and an optical head using it. In the focus error detecting method, a light beam is emitted from a light source, the beam is given positive and negative astigmatism by a diffraction grating or an acoustooptic element in a focusing optical system, beams thus formed are focused on an information recording surface, the beams reflected from the information recording surface are received by photo-detecting elements in separated optics, the reflected beams with positive and negative astigmatism are compared with each other to take a difference in a focus error detecting circuit, and a focus error detecting signal is obtained on the basis of the difference. The focus for the optical head can be adjusted using the focus error detecting signal.

Focus error detecting method and optical head using the same

An optical information processing apparatus comprising a diffraction grating for producing a zero-order beam which is a beam emitted by a light source and allowed to pass therethrough and two plus and minus first-order sub-beams respectively having positive and negative astigmatisms, radiated in directions at slight angles different from the main beam, wherein said two sub-beams are focused at opposite positions across said main beam, wherein focusing control is performed by a focusing error signal detected from a difference of signal amplitudes obtained from the respective reflected light quantities of said two sub-beams and wherein tracking control is performed by an off-track signal obtained from a signal according to a reflected light quantity of said main beam. In an apparatus for magneto-optically reproducing information, above all else, a wave plate is inserted between the focusing lens and the separating optical system, thereby increasing the reflected light quantities and stabilizing the magneto-optical signal, focusing signal and tracking signal.

Optical information processing apparatus and method of controlling

Disclosed herein is a compact, adjustment-free, unitary optical head wherein diffraction grating made of a birefrigence material and having convexities and concavities of grating grooves so set that the difference of their optical path lengths is some multiples and a half of the wavelength for an ordinary beam and an extraordinary beam, a diffraction grating providing astigmatisms to .+-.1 order beams, a quarter wavelength plate, and other optical components, are interposed between a semiconductor laser and a focussing lens and are stored inside an optical head body filled with a dry nitrogen gas. A focus error detection signal is obtained from the difference of the degrees of modulation of the .+-.1 order reflected beams by pre-wobbled pits, and adjustment of the optical beam can be carried out by driving the body by a two-directional head actuator.

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Tokyo, Japan

Mariko Umeda