Hitachi, Ltd.

Other

Fujifilm Business Innovation Corp.

Hitachi-lg Data Storage, Inc.

Nippon Victor Kabushiki Kaisha

Takashi Hoshino

Toshimitsu Kaku

Akihiro Asada

Takao Arai

Masaaki Kurebayashi

Junichi Ishii

Masaharu Kobayashi

Tetsuya Ikeda

Hidehiko Kando

Yasuhito Tanaka

Hideo Ohnuki

Hiroo Okamoto

Keizo Nishimura

Hiromichi Tanaka

Takehiko Sekine

Makoto Nihei

Hideo Oonuki

Hidehiko Kandou

Hiroyuki Kimura

Tomoaki Yoshioka

Yoshizumi Watatani

Yoko Miyamoto

Takashi Takeuchi

Toshiaki Baba

Shigeru Yamazaki

Harukuni Kobari

Shinji Okuyama

Chihiro Iijima

Noboru Kojima

Toshifumi Shibuya

Chitoshi Hibino

Masami Nishida

An image forming apparatus includes: a colorant image former; an image holder configured to hold a colorant image formed by the colorant image former and to be rotationally driven; a transfer member configured to transfer the colorant image onto a recording medium, which is transported from an upstream side, by sandwiching the recording medium between the transfer member and the image holder, and rotationally driving the transfer member to transport the recording medium to a downstream side; and a contact-and-separation mechanism configured to relatively contact or separate the image holder and the transfer member, in which, in response to an abnormality being detected, the image forming apparatus operates in a mode in which the contact-and-separation mechanism relatively separates the image holder and the transfer member, and then rotational driving of the transfer member is stopped after rotational driving of the image holder is stopped.

Image forming apparatus

An optical disk apparatus uses a laser driver which can measure the frequency of the high-frequency superimposed current of the semiconductor laser simply and accurately. The apparatus includes a semiconductor laser which emits a laser beam onto the optical disk, a laser driver which drives the semiconductor laser with a current, with the high-frequency current being superimposed thereon, and measures the frequency of the high-frequency current, and a main controller which controls the frequency of the high-frequency current produced by the laser driver by using the frequency measured by the laser driver.

Laser driver, optical disk apparatus using the same, and laser control method

A laser waveform generation function is provided in a laser driving waveform generatornear a laser. A recording clock generatoris included in the laser driving waveform generatorto generate a clock with a frequency higher than that of a synchronizing clock. This allows a recording laser current (waveform) to be generated without transmission of a high frequency signal from the modulatorFurther, because the synchronizing clockis stopped upon a reproduction operation including reproduction operation in an ID unit, undesired effects on a reproduction operation such as ID reproduction can be reduced. Because the response speed of the recording clock generatorcan be changed, a high precision clock can be generated. Thus, a high-precision recording laser current (waveform) can be generated.

Information recording and reproducing apparatus for updating the waveform of a laser based on position information

According to the present invention, in an optical disk apparatus constructed to supply signals for controlling a semiconductor laser drive circuit provided to an optical pickup from a signal processing circuit through a flexible cable, the semiconductor laser drive circuit is so constructed as to generate a drive current signal for the semiconductor laser on the basis of a binary signal and a clock signal which are supplied from the signal processing circuit through the flexible cable and the signal processing circuit is so constructed as to stop supplying the block signal to the semiconductor laser drive circuit through the flexible cable during reproduction of data, and to start supplying the clock signal to the semiconductor laser drive circuit before recording of data.

Optical disk apparatus wherein recording clock signal is stopped being supplied to semiconductor laser drive circuit on optical pickup during reproduction operation

An information recording/reproducing apparatus includes a semiconductor laser, a laser driver which drives the semiconductor laser, an optical system which focuses light emitted from the semiconductor laser on an information recording medium, a photodetector which detects light reflected from the information recording medium, and outputs a reflection light signal, a modulation circuit which modulates information in accordance with a predetermined rule, and outputs a binary signal representing the modulated information, and a calculation/control circuit which controls the modulation circuit. The laser driver includes a delay circuit, and receives the binary signal, generates a recording current signal corresponding to the binary signal through the delay circuit, and transmits an output of the delay circuit to the calculation/control circuit as a monitor signal. The calculation/control circuit generates a timing signal for sampling and holding the reflection light signal based on the monitor signal.

Information recording/reproducing apparatus with laser driver

A laser drive integrated circuit and an optical disk apparatus using the laser drive integrated circuit for forming high-density marks. The optical disk apparatus includes a drive waveform information storage unit for storing at least one information of a drive waveform for driving a laser diode in response to a binary recording signal to be recorded in a recording medium, and a drive waveform decoder for decoding the drive waveform based on the information stored in the drive waveform information storage unit. A recording strategy can be changed in accordance with variations and fluctuations of recording media or characteristics of the recording media, while at the same time reducing a number of signal lines in flexible wiring and alleviating effects of signal distortion in the signal lines.

Laser drive integrated circuit and optical disk apparatus using the same

A laser drive circuit includes a first current supply unit which supplies a first drive current to a first laser diode based on a drive waveform signal generated by a drive waveform generating unit, a second current supply unit which supplies a second drive current to a second laser diode based on the drive waveform signal generated by the drive waveform generating unit, and a switching unit which selectively supplies the drive waveform signal generated by the drive waveform generating unit to one of the first current supply unit and the second current supply unit. The drive waveform generating unit may be part of the laser drive circuit, or may be separate from the laser drive circuit, and may include a drive waveform information storage unit which stores a recording strategy according to a type of disk.

A laser driver for driving a semiconductor laser for use in recording information by irradiating light on an information recording medium includes a device, including a PLL circuit, for obtaining (1) information modulated in accordance with a predetermined rule and (2) a clock signal, and outputting a recording current signal corresponding to a modulation signal representing the modulated information through the PLL circuit. The PLL circuit oscillates at a high frequency in synchronism with the clock signal. The laser driver further includes a PLL unlock detection circuit for detecting an oscillating condition of the PLL circuit, and for outputting a detection signal indicative of the oscillating condition of the PLL circuit outside the laser driver as a monitor signal.

A laser drive (LD) unit according to the present invention is provided with a laser drive waveform controller into which information for setting the laser drive is entered from a controller for generating a laser drive waveform on the basis of that information and supplying an indicated amperage; an LD current setting unit for setting a laser drive current matching the indicated amperage; an LD current output unit for varying the laser drive current on the basis of the laser drive waveform and supplying the current so varied to a laser diode and a current setting corrector into which a monitor signal obtained at the time of monitoring the laser beam emission from the laser diode is monitored, for correcting the laser drive current set by the current setting unit by using that monitor signal to adjust the power of the laser diode The laser drive waveform controller current setting unit current output unit and current setting corrector are formed on the same substrate.

Laser drive unit and information recording/reproducing apparatus

According to the present invention, in an optical disk apparatus constructed to supply signals for controlling a semiconductor laser drive circuit provided to an optical pickup from a signal processing circuit through a flexible cable, the semiconductor laser drive circuit is so constructed as to generate a drive current signal for the semiconductor laser on the basis of a binary signal and a clock signal which are supplied from the signal processing circuit through the flexible cable and the signal processing circuit is so constructed as to supply the clock signal during recording of data and stop the supply of the block signal during reproduction of data.

A laser drive integrated circuit and an optical disk apparatus using the laser drive integrated circuit for forming high-density marks. The optical disk apparatus has a drive waveform information storage unit for storing at least one information of the drive waveform for driving a laser diode in response to a binary recording signal recorded in a recording medium and a drive waveform decoder for decoding the drive waveform based on the information stored in the drive waveform information storage unit. The recording strategy can be changed in accordance with the variations and fluctuations of recording media or the characteristics of the recording media, while at the same time reducing the number of signal lines of flexible wiring and alleviating the effect of the signal distortion.

A laser waveform generation function is provided in a laser driving waveform generator near a laser A recording clock generator is included in the laser driving waveform generator to generate a clock with a frequency higher than that of a synchronizing clock This allows a recording laser current (waveform) to be generated without transmission of a high frequency signal from the modulator Further, because the synchronizing clock is stopped upon a reproduction operation including reproduction operation in an ID unit, undesired effects on a reproduction operation such as ID reproduction can be reduced. Because the response speed of the recording clock generator can be changed, a high precision clock can be generated. Thus, a high-precision recording laser current (waveform) can be generated.

Information recording and reproducing apparatus having semiconductor laser drive circuitry in its pickup

An information recording/reproducing apparatus which can record and reproduce information data into and from various kinds of recording mediums has a laser driver which enables recording strategy control for each kind of recording medium. The laser driver receives an NRZ binary signal and a clock signal synchronized with the NRZ binary signal from a modulation circuit, and generates a recording current signal corresponding to the NRZ binary signal. The laser driver includes a PLL circuit disposed in the laser driver which oscillates at a recording frequency, and an unlock detection circuit which detects an oscillating condition of the PLL circuit and outputs a detection signal indicative of the oscillating condition of the PLL. A recording operation of the information recording/reproducing apparatus is controlled based on the detection signal outputted from the unlock detection circuit.

Growing community of inventors

Yokohama, Japan

Takashi Hoshino