Samsung Electronics Co., Ltd.

Hewlett-packard Development Company, L.p.

Yonsei University

An-sik Jeong

Jong-hyun Shin

Kyung-geun Lee

Tatsuhiro Otsuka

In-Joo Kim

Yong-geun Kim

Chong-sam Chung

Wook-yeon Hwang

Jin-Kyung Lee

Joon Seon Jeong

Kyung-hwan So

Hyun-seok Yang

Hong-ki Jung

Mu-kun An

Joong-gon Kim

Noh-cheol Park

A power supply device is provided. The power supply device includes an AC/DC converter configured to convert an input AC power into a first DC power having a predetermined size, and to output the first DC power, a DC/DC converter configured to convert the first DC power into a second DC power according to an enable signal, and a switch including a soft switch connected to the first DC power at one end, and configured to, in response to the soft switch being turned on, voltage-distribute the first DC power, and to provide the voltage-distributed first DC power to the DC/DC converter as an enable signal.

Power supply device and image forming apparatus having the same

A switching mode power supply and a method of supplying power by using the same. The switching mode power supply includes a converting unit to convert an alternating current (AC) voltage input to the switching mode power supply to at least one direct current (DC) voltage by using at least one transformer, and a voltage controller to control a voltage level of an output voltage to be output to a system controller of the image forming apparatus from among the at least one DC voltage, where the system controller controls operations of the image forming apparatus. The voltage controller includes a switching unit to switch the voltage level of the output voltage from a first voltage level to a second voltage level when the image forming apparatus enters a power saving mode, where the second voltage level is lower than the first voltage level.

Switching mode power supply usable in an image forming apparatus, and image forming apparatus and method of supplying power by using the same

Power supply device and an image forming apparatus having the power supply device are provided. The power supply device includes an input unit to input alternating current (AC) power, a converter to convert the input AC power to direct current (DC) power having a preset level and to output the DC power, and a sensor to be connected to the input unit in parallel and to sense whether the AC power has been input. The sensor includes a transformer to receive the AC power and to output a sensing signal having a level reduced more than a level of the AC power, and a resistor unit connected to the transformer in series so that a current of the AC power input into the transformer is lower than or equal to a preset current.

A switching-mode power supply (SMPS) for an image forming apparatus which may prevent an overvoltage supplied to the SMPS, and damage to circuits in the SMPS in the image forming apparatus. The SMPS includes a rectifying circuit to rectify an alternating-current (AC) voltage input from an external power supply source into a direct-current (DC) voltage, a transformer to transform the rectified DC voltage input to a primary coil and output the transformed DC voltage to a secondary coil, a main switch that is connected to the primary coil and switches an output of the transformer, a first overvoltage detecting unit to determine whether the rectified DC voltage is an overvoltage by comparing the rectified DC voltage with a first reference voltage, and a switching control unit to control a switching operation of the main switch based on a result of the determination.

Switching-mode power supply (SMPS) having overvoltage cutoff function, and method of cutting off overvoltage and image forming apparatus using the SMPS

An image forming apparatus having two or more different rated voltages, the image forming apparatus including a voltage detecting unit, which detects a voltage level of alternating current (AC) power supplied from outside of the image forming apparatus; a control unit, which outputs a control signal according to the detected voltage level; a fusion driving circuit, which controls a number of waveforms and phase of the AC power according to the control signal and outputs the controlled AC power as fusing power; and a fuser including a heat generating body having a negative temperature coefficient (NTC) characteristic, which receives the fusing power and generates resistance heat; and a heating member, which is heated by the heat generated by the resistance heat generating body and fuses an image formed on a printing medium.

Image forming apparatus and method of controlling fusing temperature of the same

An apparatus to protect a half or full bridge circuit including a first switching unit and a second switching unit in an image forming apparatus performing induction heating, the apparatus including a switching control unit to control operations of the first switching unit and the second switching unit by generating and outputting a first driving signal to turn on or off the first switching unit and a second driving signal to turn on or off the second switching unit; and an arm-short detecting unit to output a disable signal to stop operation of the switching control unit in response to the first driving signal and the second driving signal simultaneously being signals to turn on the first switching unit and the second switching unit.

Apparatus and method to protect half or full bridge circuit including first switching unit and second switching unit in image forming apparatus performing induction heating

Provided is a method of controlling electric power of a coil which performs induction heating in an imaging apparatus. The method includes: detecting an input current of the coil; detecting a resonant current of the coil; calculating a difference between the detected resonant current and the detected input current; and controlling electric power supplied to the coil based on the difference. These operations are repeatedly performed whenever the detected input current is changed.

Method and apparatus to control electronic power of coil which performs induction heating in imaging apparatus

An optical disk apparatus includes a light focusing element arranged to face a disk and to focus light emitted from a light source on the disk, an actuator to move the light focusing element towards and away from the disk according to an actuator driving voltage, a light intensity detection unit to detect an intensity of light reflected by the light focusing element and generate a gap error signal based on the detected intensity, a servo unit to generate the actuator driving voltage and a predetermined threshold voltage based on the gap error signal generated by the light intensity detection unit and to provide the actuator driving voltage to the actuator, a distance detection unit to detect a first distance at which the actuator driving voltage is maintained when the threshold voltage is detected using the gap error signal and to detect a second distance at which a gap between the light focusing element and the disk is shorter than the first distance and at which a gap servo operation is started based on the gap error signal; and a control unit to control the servo unit to start the gap servo operation based on the detected first and second distances.

Optical disk apparatus and method of driving the same

An optical disc apparatus, and a method of driving the same, includes a light focusing element disposed to focus light emitted from a light source onto a disc; an actuator to move the light focusing element toward or away from the disc according to a voltage applied to the actuator; a light intensity detection unit to detect the intensity of light reflected from the disc; a servo unit to generate a gap error signal and a third voltage, the third voltage being the sum of a first voltage and a second voltage, and to apply the generated third voltage to the actuator; and a control unit to control the servo unit to perform a gap pull-in operation when the light focusing element is moved toward the disc according to the gap error signal and the third voltage.

Optical disc apparatus and method of driving the same

A gap pull-in method and an optical disc apparatus. Whether light condensed on a disc as an actuator ascends is near-field light is determined using a gap error signal. The range of an actuator driving voltage value during a section where the decrease rate of the gap error signal is constant is obtained when it is determined that the light condensed on the disc is near-field light. Gap pull-in is performed on the disc during a section where the actuator driving voltage value is within the obtained range.

Near-field gap pull-in method and optical disc apparatus therefor

A recording method, a recording apparatus, and an optical recording medium that can improve quality of a signal reproduced from a high multi-speed recording medium. The recording method includes generating a box type recording pattern including a first pulse, which has a duration determined according to a length of a recording mark and which has a first power level, and a second pulse which has a second power level different from that of the first power level, and recording data according to the box type recording pattern.

Recording method to generate a box type recording pattern with a first pulse having a first power level and a second pulse having a second power level, and recording apparatus, and optical recording medium for the same

A near field optical recording/reproducing apparatus includes a light source, an objective lens to form a spot by focusing light emitted from the light source, a solid immersion lens to generate an evanescent wave by using the spot formed by the objective lens, a photodetector to measure an amplitude of a gap error signal that is totally reflected by the solid immersion lens, and an operating unit to generate a normalized gap error signal by using an amplitude of a driving signal applied to the light source and the amplitude of the gap error signal measured by the photodetector.

Near field optical recording/reproducing apparatus and method of normalizing gap error signal of the same

An optical disk reproducing apparatus to equalize and reproduce a signal optically read from an optical disk includes a controller to determine a number of regions to divide the optical disk into according to a reproduction frequency variation corresponding to a signal quality variation, and an equalizer to filter signals optically read from the divided regions with a cut-off frequency corresponding to the reproduction frequency variation.

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Hwaseong-si, South Korea

An-sik Jeong