Abstract: An electronic device according to various embodiments of the present invention comprises: a housing; a keyboard arranged on the front surface of the housing; a plurality of first magnets arranged along the periphery of the keyboard; and a keyboard cover comprising a cover portion that covers the keyboard and a plurality of second magnets arranged on the edge of the cover portion so as to correspond to the plurality of first magnets, respectively, wherein the keyboard cover can be attached to/detached from the front surface of the housing by means of the drawing force between the plurality of first magnets and the plurality of second magnets. Various other embodiments are also possible.

Abstract: An electronic device according to various embodiments of the present invention comprises: a housing; a keyboard arranged on the front surface of the housing; a plurality of first magnets arranged along the periphery of the keyboard; and a keyboard cover comprising a cover portion that covers the keyboard and a plurality of second magnets arranged on the edge of the cover portion so as to correspond to the plurality of first magnets, respectively, wherein the keyboard cover can be attached to/detached from the front surface of the housing by means of the drawing force between the plurality of first magnets and the plurality of second magnets. Various other embodiments are also possible.

Abstract: An electronic device is provided, which uses magnetic force to couple to an external device. The electronic device includes a housing, a magnet positioned within the housing, and an elastic body connected to the magnet. At least a portion of the elastic body changes a shape or a position thereof, in response to a change of a magnetic force of the magnet.

Abstract: An electronic device is provided, which uses magnetic force to couple to an external device. The electronic device includes a housing, a magnet positioned within the housing, and an elastic body connected to the magnet. At least a portion of the elastic body changes a shape or a position thereof, in response to a change of a magnetic force of the magnet.

Abstract: An image forming apparatus, a developing agent container and a controlling method of the same that improves a supply rate of developing agent from a developing agent container to a developing device that provides the developing agent to an image carrier.

Abstract: A color registration apparatus that independently forms images of predetermined respective colors and compensates a mis-registration between the overlapped images of respective colors employed in an image forming apparatus of forming a color image by overlapping the images of respective colors, includes a detecting unit to detect a contour form and positional information of respective color patterns formed on an image transfer path by the image forming apparatus proportional to a corresponding format of a printing medium where the color image will be transferred, and a controller to compensate a mis-registration between the overlapped images of respective colors through based on data detected by the detecting unit.

Abstract: An image forming apparatus including a power supply unit which supplies high voltage AC power, a developing unit having at least one developing roller to receive first AC power from the power supply unit to supply a developer to an image receptor, and an erasing unit to receive second AC power to attenuate high frequency noise of the developing unit.

Abstract: An image forming apparatus, a developing agent container and a controlling method of the same that improves a supply rate of developing agent from a developing agent container to a developing device that provides the developing agent to an image carrier.

Abstract: A medium detecting device to detect information corresponding to a printing medium fed through a medium transport path, includes a detecting unit to detect a contour form information of the printing medium; and a discriminating unit to determine a format of the printing medium and feeding information based on the contour form information of the printing medium detected by the detecting unit.

Abstract: A color registration apparatus that independently forms images of predetermined respective colors and compensates a mis-registration between the overlapped images of respective colors employed in an image forming apparatus of forming a color image by overlapping the images of respective colors, includes a detecting unit to detect a contour form and positional information of respective color patterns formed on an image transfer path by the image forming apparatus proportional to a corresponding format of a printing medium where the color image will be transferred, and a controller to compensate a mis-registration between the overlapped images of respective colors through based on data detected by the detecting unit.

Abstract: A method of optimizing the amount of toner of an electrophotographic printer is provided. The method includes measuring a life span of the development roller in use. The speed of a development roller, which corresponds to the measured life span of the development roller, is calculated from a lookup table. The development roller speed is adjusted according to the calculated development roller speed.

Abstract: A high developing voltage supply apparatus includes solenoid power switches, and a high developing voltage driver selectively outputting a solenoid driving signal to close one of the solenoid power switches to electrically close a corresponding mechanical contact, applying a high developing voltage to one of color development rollers corresponding to the mechanical contact closed and Kased on an image to be printed. A high developing voltage supply supplies the high developing voltage to developing roll shafts of the other color development rollers to stabilize potentials of the developing roll shafts, or, in the alternative, the high developing voltage supply apparatus may include a voltage supply supplying a self-biased voltage to the other color development rollers using the high developing voltage formed with a DC voltage VDC and an AC voltage VAC superimposed.

Abstract: A controlling method of an image forming apparatus for finely controlling the sensitivity of a density sensor in response to various changes of a printing environment. The controlling method of the image forming apparatus uses one or more of the following methods, alone or in any combination, to control the sensitivity of a density sensor. The methods can include a sensitivity correction method for controlling an output signal of the density sensor according to amount of light irradiated to an image carrier from a light source, a sensitivity correction method for correcting a reference value according to an output signal of the density sensor, and a sensitivity correction method for changing the signal output from the density sensor using a predetermined process.

Abstract: A method and apparatus for controlling a transfer voltage applied to a transfer roller in order to transfer a toner image formed on an intermediate transfer member to a medium in a multi-path type electrophotographic image forming device are provided. An amount of toner transferred from the photoconductive member to the intermediate transfer member is detected, and a transfer voltage applied to the transfer roller using the detected amount of toner is determined. Accordingly, when an optimum transfer voltage is determined to be applied to the transfer roller in the multi-path type electrophotographic image forming device, by determining the transfer voltage applied to the transfer roller considering the amount of toner detected while the toner image is transferred from the photoconductive member to the intermediate transfer member, an improved printing quality can be maintained regardless of the coverage of an entire printing image.

Abstract: A method and apparatus for measuring the color tone density of an image output from a multipass color printer consumes a minimum of time by using a test pattern that includes test patches for all of the developing units in the printer. The method includes developing a test pattern, which includes test patches for all developing units, on an organic photo conductor, measuring the color tone density of the developed test pattern, and adjusting developing variables according to the measured color tone density. Accordingly, it is possible to reduce the time required to measure the color tone density of an image output from a multipass color printer, using the test pattern.

Abstract: A tone compensation method for a color printer and a color printer having a tone compensator are provided, wherein the method includes the steps of (a) acquiring a reference tone reproduction curve of print colors based on a printing environment, (b) forming sample patterns for one or more colors on a predetermined object medium, (c) forming a sectional tone reproduction curve by using the sample patterns, and (d), adjusting one or more print variables to compensate the sectional tone reproduction curve in order to reduce sectional errors between the reference tone reproduction curve and the sectional tone reproduction curve. Accordingly, it is possible to provide a tone compensation method capable of compensating for a sectional tone reproduction curve to approximate a reference tone reproduction curve without complicated mathematical calculations, and which is substantially unaffected by external disturbances and noise.

Abstract: A method of optimizing the amount of toner of an electrophotographic printer is provided. The method includes measuring a life span of the development roller in use. The speed of a development roller, which corresponds to the measured life span of the development roller, is calculated from a lookup table. The development roller speed is adjusted according to the calculated development roller speed.

Abstract: A computer includes a main casing to accommodate a plurality of hardware components, a supporting bracket provided in the main casing and having an entrance opening to accommodate and support a first peripheral unit, and a clip unit coupled to the supporting bracket to cover at least a region of the entrance opening and to contact a second peripheral unit placed above the first peripheral unit in the supporting bracket to resiliently support the second peripheral unit. Thus the computer, allows an additional peripheral unit to be easily mountable to and detachable from the main casing.

Abstract: Disclosed is a device for measuring the density of an image in regard to a liquid test patch. The device has: a fan for drying a test patch by blowing air to the test patch disposed on at least one of a photosensitive medium, a photosensitive belt and printing paper; a sensor for projecting infrared light to the dried test patch and measuring the density of the test patch based on the reflected light of the infrared light reflected from the test patch; and an adjustment unit for adjusting the mixing ratio of a toner and a carrier in accordance with the measured density. The device measures the amount of light reflected from the dried liquid test patch, thus allowing the density of the image to be measured accurately.

Abstract: A duplex electro-photographic developing machine including a printing medium tray loading a printing medium, a tray open/closed detecting unit detecting whether the printing medium tray has been opened and closed, a transferring roller transferring a toner image onto the printing medium, a resistance measuring unit measuring a resistance value of the printing medium passing the transferring roller, and a concentration controlling unit controlling a concentration of the toner image according to the measured resistance value measured by the resistance measuring unit in response to the printing medium tray having changed from an open state to a close state.