Canon Kabushiki Kaisha

Akira Miyashita

Nobuyuki Tonegawa

Hirotake Ando

Yutaka Ogasawara

Takaaki Ashinuma

Takayuki Seki

Tsutomu Shiratori

Takeshi Yamawaki

Shunpei Kimura

Shuhei Tada

In a conventional current resonance switching power source, the burst period of a burst operation could not be sufficiently prolonged, and the efficiency characteristics were insufficient in a light load. In order to improve this, an embodiment of the present invention generates, upon operating in the burst mode, a control signal in accordance with a comparison result of a first reference voltage and a secondary side voltage of a transformer and a comparison result of a second reference voltage and the secondary side voltage of the transformer. Subsequently, the oscillation operation timing of an oscillator that performs an oscillation operation to the transformer and the oscillation frequency that changes the voltage excited on the secondary side of the transformer are controlled based on the control signal.

Power supply apparatus, printing apparatus, and control method

In a discharging state determination method and apparatus for detecting discharging state from each nozzle of a printhead which discharges droplets, each of the nozzles of the printhead is driven, and the discharging state from each driven nozzle is detected and stored as a physical amount in a memory. A threshold for determining whether the discharging state of each nozzle of the printhead is normal or abnormal is calculated by using the physical amount corresponding to each nozzle and stored in the memory. The physical amount corresponding to each nozzle is evaluated on the basis of the threshold, and it is determined whether the droplet discharging state of each nozzle is normal or abnormal.

Apparatus for determining discharging state of liquid droplets and method, and inkjet printer

An information recording and/or reproducing apparatus for recording data onto and/or reproducing data from a recording medium by irradiating a light beam emitted from a light source onto a desired track of the recording medium through an optical system. The apparatus includes (i) a single processor for executing an input/output control of the data for the apparatus and a servo process of the light beam such that the input/output control of the data and the servo process of the light beam are alternately switched at a predetermined period, and (ii) an actuator for moving the light beam on the basis of the servo process of the processor. The precision of the servo process is changed so that the precision is increased when an amount of an external disturbance is large.

Information recording and/or reproducing method and apparatus in which a

An information recording and/or reproducing method and apparatus for effecting recording of data onto and/or reproducing of data from a recording medium by irradiating a desired track on the recording medium with a light beam emitted from a light source through an optical system. In the apparatus, a single processor executes an input/output control of the data for the apparatus and a power control of the light beam by interrupting the input/output control at every predetermined period. The processor inhibits the interrupt power control of the light beam in accordance with a predetermined situation.

A test recording method is provided to determine an optimum power of a light output from a light source in erasing pieces of information recorded on a land and a groove of a recording medium. A predetermined signal is recorded on a predetermined track of the medium. Data on a track adjacent to the track where the signal is recorded is erased with different erasing powers. The signal recorded on the track is reproduced to detect a reproduction signal. An optimum erasing power is set on the basis of the reproduction signal and the different erasing powers.

Test recording method and optical information recording/reproducing

An information recording and/or reproducing apparatus for recording data onto and/or reproducing data from a recording medium such as a magnetic disk, a magnetooptic disk, or the like by irradiating a laser beam emitted from a light source such as a semiconductor laser onto a desired track of the recording medium through an optical system, wherein the apparatus includes a single processor for executing an input/output control of data for the apparatus and a servo process of the laser beam by interrupting the servo process between the input/output control at every predetermined period. The processor switches a precision of the servo process in accordance with a predetermined situation such as a change in operating mode.

A write test method for use in a recording process for recording information is effected by such that the power of a laser light is modulated to form a high-temperature state and a low-temperature state on a recording medium. First, a predetermined signal is recorded on the recording medium while varying the power level of the laser light. The information recorded on the recording medium is reproduced to detect the power level of the laser light, immediately before formation of the high-temperature state, based on the amplitude of a reproduced signal. The power levels of the laser light for forming the low-temperature state and for forming the high-temperature state are determined on the basis of the detected power level.

Write test method for use in recording process for recording information

An optical information recording and/or reproducing apparatus includes a first semiconductor laser for generating a light beam for recording or erasing information on an optical information recording medium. Also provided is a second semiconductor laser for generating a light beam for reproducing recording information from the optical information recording medium, and a first direct current supplying circuit for supplying a first direct current to the first semiconductor laser. A second direct current supplying circuit supplies a second direct current to the second semiconductor laser, and a high-frequency current supplying circuit supplies high-frequency currents to the first semiconductor laser and the second semiconductor laser. The high-frequency current supplying circuit supplies a smaller high-frequency current to the first semiconductor laser than to the second semiconductor laser.

Optical information recording/reproducing apparatus supplying a smaller

An optical information recording and/or reproducing apparatus includes a first light source for recording or erasing information, a first current source for modulating a light beam from the first light source in accordance with a recording signal, a second light source for verification, and a second current source for supplying a current to the second light source to cause the second light source to emit a reproducing light beam. The light beam from the first light source leads on an information track on an optical recording medium, and the light beam from the second light source follows on the information track. Based on reflected light from the optical recording medium, of the light beam from the second light source, information recorded by the light beam from the first light source is reproduced for verification. The apparatus further has an inductor disposed in a current supply path from the second current source to the second light source, which has an impedance sufficiently larger than an impedance of the second light source at a recording signal frequency, and a high-frequency oscillator for modulating a light output from the second light source, which applies a high-frequency current with a frequency sufficiently higher than the recording signal frequency.

Optical information recording and/or reproducing apparatus in which a

An optical information recording and/or reproducing apparatus radiates a leading light beam from a first light source and a trailing light beam from a second light source to follow the leading beam onto an information track in a recording medium and to perform recording of information with the leading beam and verification with the trailing beam. The apparatus includes a common photosensor for detecting parts of light quantities of the light beams from the first and second light sources, a device for intermittently turning off the light beam not used for reproduction of preformat portions out of the leading beam and trailing beam, with respect to the preformat portions, and a light output controller for controlling the leading beam from the first light source and the trailing beam from the second light source at respective predetermined light outputs, based on the light quantities detected by the photosensor and reference values preliminarily set, when one of the leading beam and trailing beam is off and when both of the leading beam and trailing beam are on.

Optical information recording and/or reproducing apparatus and method

There is an information reproducing apparatus having a first comparator for comparing a reproduction signal from an information recording medium such as a magnetooptical disc and a first reference signal, thereby binarizing the reproduction signal, a clock signal generating circuit for generating a clock signal from the signal binarized by the first comparator, and a synchronous circuit for synchronizing the binary signal by the clock signal. A phase comparator compares the phase of the binary signal and the phase of the output of the synchronous circuit, a charge/discharge circuit such as a charge pump circuit is driven by an output of the phase comparator, and a second comparator compares an output of the charge/discharge circuit and a second reference signal. The first reference signal is controlled by an output of the second comparator synchronously with the binary signal or the output of the synchronous circuit. The second reference signal changes interlockingly with a change in frequency of the clock signal forming circuit.

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Tokorozawa, Japan

Akira Miyashita