Abstract: An image forming apparatus for determining a state of conveying a printing medium and a method thereof are disclosed. The image forming apparatus includes a convey belt rotating in a caterpillar manner for conveying a printing medium to a photoconductor. A charge roller charges a printing medium that enters the convey belt. A convey roller faces the charge roller and forms a convey nib with the charge roller. A transfer unit transfers a developer image formed on the photoconductor to the printing medium. A resistance detector constantly detects resistance of the convey roller. A controller determines whether the resistance is varied within a reference time.

Abstract: Provided is an optical semiconductor device including: an active layer having at least one quantum well layer and at least one barrier layer; a clad layer formed adjacent to the active layer; and a tunneling barrier layer formed between the active layer and the clad layer to be connected to the quantum well layer and formed of a material having a band-gap energy larger than the barrier layer, whereby it is possible to improve the drive characteristics at a high temperature and a high drive current by increasing a confinement effect of carriers such as electrons and holes in the active layer.

Abstract: Provided is a monolithic integrated semiconductor broad band light source. In the monolithic integrated semiconductor broad band light source, an electro absorption modulator, a semiconductor optical amplifier, and a light emitting diode are integrated on an InP substrate. Ions are implanted among the electro absorption modulator, the semiconductor optical amplifier, and the light emitting diode to electrically insulate the electro absorption modulator, the semiconductor optical amplifier, and the light emitting diode from one another. Electrodes independently implant currents into the electro absorption modulator, the semiconductor optical amplifier, and the light emitting diode. In particular, it is important to form a current intercepting layer and electrically insulate electrodes from one another but optically connect the electrodes in terms of performance of the monolithic integrated semiconductor broad band light source.

Abstract: A channel switching function is added to a wavelength division multiplexing passive optical network (WDM-PON) system, which is an access optical network system, and the potential transmission rate is increased by combining wide wavelength tunable lasers and a time division multiplexing (TDM) data structure and properly using the necessary optical components. In addition, when the wavelength of a light source or an arrayed waveguide grating (AWG) changes, the wavelength is traced and the magnitude of a transmitted signal is maximized without an additional detour line using a loop-back network structure. Furthermore, fewer thermo-electric controllers (TECs) are required for stabilizing the temperature of an optical line terminal (OLT) using wavelength tunable lasers, each laser electrically changing its wavelength.

Abstract: Provided is a waveguide photodetector including: a first clad layer disposed on a substrate; a core layer disposed on the first clad layer and for absorbing predetermined light; a second clad layer disposed on the core layer; and at least one subsidiary layer inserted in the first clad layer and the second clad layer. In this structure, the photodetector has about the same spot size as that of an optical fiber or planar lightwave circuit (PLC), so that incident light can be absorbed without loss, and the photodetector can more efficiently combine with the optical fiber or PLC and operate even at high power.

Abstract: A toner composition and a method of preparing the same provide a toner composition that includes a coloring agent, a charge control agent, a binder, a wax and an internal additive, wherein the coloring agent and wax are contained as a master batch, and the internal additive includes toner particles having at least one component selected from a hydrophobic silica, a hydrophobic titanium oxide and/or a hydrophobic aluminain e.g., an electrophotographic imaging apparatus.

Abstract: Provided is a planar lightwave circuit (PLC) type optical transceiver module, in which for a diplex optical transceiver module that uses different wavelengths in upstream and downstream, an optical waveguide connected to a light-receiving unit is a multi-mode waveguide and an optical waveguide connected to the light-emitting unit is a single mode waveguide, and further, for a triplex optical transceiver module that uses one upstream wavelength and more than two different downstream wavelengths, an optical waveguide connected to the light-receiving unit, which is a waveguide-type photo diode, is a multi-mode waveguide and an optical waveguide connected to the light-emitting unit is a single mode waveguide, whereby even when there is an alignment error of a thin film filter due to irregularity provided in forming a trench, the optical waveguide connected to the light-receiving unit is formed wider than the optical waveguide connected to the light-emitting unit so that the loss during transmission of the optical

Abstract: A photosensitive drum with a fixed photosensitive sheet on the outer circumference of a cylindrical body that defines an image forming area. A spacer is disposed on at least one end of the outer portion of the image forming area on the cylindrical body. The spacer pushes either an electrostatic charging roller or a developing roller, which access the photosensitive sheet during an image forming process, when a seam of the photosensitive sheet approaches either the electrostatic charging roller or the developing roller to distance either the electrostatic charging roller or the developing roller from the seam of the photosensitive sheet.

Abstract: Provided is a semiconductor laser including a substrate etched into a mesa structure, an active layer, clad layers, a current blocking layer, an etch-stop, an ohmic contact layer, and electrodes, and a method for manufacturing the same, whereby it is possible to improve a ratio of light output to input current by blocking a leakage current flowing outside an active waveguide in a BH laser.

Abstract: An organic photoconductive (OPC) unit of an image forming apparatus and a gear assembly arranged in the OPC unit. The gear assembly includes a drum gear formed on a flange of an OPC drum, a cleaning gear driven by a receiving power from the drum gear, and at least one idle gear interposed between the drum gear and the cleaning gear and transmitting the rotational force of the drum gear to the cleaning gear. Therefore, it is possible to drive a plurality of additional rollers with a single power source, and easy to connect the OPC drum with the gears when the OPC drum is fitted into the OPC unit. In addition, because the gear assembly is constructed in a compact form, it is possible to reduce the volume of the OPC unit.

Abstract: A photoreceptor unit includes a photoconductive drum assembly, a housing to enclose the photoconductive drum assembly to be rotatable therein, a handgrip rotatably formed on the housing, and a stopper to prevent the housing with the photoconductive drum assembly from becoming lopsided toward its preponderant side of the housing with respect to a center of rotation of the handgrip when the housing is lifted up by the handgrip.

Abstract: A housing assembly of an OPC unit to protect an OPC drum in an image forming apparatus includes a main housing enclosing at least a half of a large-diameter OPC drum and provided with a main-opening selectively contacting a plurality of developing units and a plurality of sub-openings, a first housing and a second housing each mounted on a side of the main housing, a handle hingedly connected to the main housing, and a plurality of brackets mounted on opposite sides of the main housing. As a result, the housing assembly of the OPC unit allows easy development, electrification, exposure, image transfer and treatment of a waste toner, and reliability of the image developing process increases due to the fixation of the developing units. Also, since the exposure of the OPC drum is minimized, an area of the OPC drum to be contaminated can be reduced.

Abstract: An organic photoconductive (OPC) drum assembly including a pipe-shaped drum body with open sides, first and second flanges connected to both sides of the drum body, a shaft penetrating the drum body and rotatably supporting the flanges, and a pair of bearings inserted between each flange and the shaft. A driving gear to receive power is integrally formed with one of the first and second flanges.

Abstract: The present invention relates to a waveguide photodetector having a good efficiency of coupling with an optical fiber or a PLC (Planar Light-wave Circuit). In order to increase size of mode beam and to effectively receive light from the optical fiber or the PLC, a thin absorbing layer is used as a core and a semiconductor having an index of refraction similar to that of the absorbing layer is used as a cladding layer. By doing so, it is possible to obtain a good efficiency of coupling with an optical fiber or a PLC. In addition, since a little amount of light proceeds along a waveguide, it is possible to obtain high operating speed even under a high power. Furthermore, by reducing difference between indexes of refraction of the absorbing layer and the cladding layer, it is possible to suppress the “carrier-trapping” generated from small difference between band gaps of the two materials.

Abstract: A developer concentration measuring apparatus of a liquid printer includes a container installed so that developer supplied to a photoreceptor web enters and is exhausted, a roller rotatably installed in the container for forming a film of the developer contained in the container on a surface thereof being exposed while rotating, a roller driving module for driving the roller to rotate at a predetermined speed, a light emitting module for emitting a predetermined amount of light to the surface of the roller where the film is formed, a light-receiving module, installed to detect light emitted from the light emitting module and passing through the film, for transmitting a signal corresponding to the amount of received light, a temperature detector for detecting the temperature of the developer contained in the container; and a concentration measuring module for measuring the concentration of the developer from information on temperature output from the temperature detector and from the signal output from the li

Abstract: An apparatus for connecting and disconnecting a developing bias power supply in an image forming system. A plurality of developers are operated in sequence to develop an electrostatic latent image formed on a photosensitive body in a predetermined color. An electro-magnetic clutch, which corresponds to each of the developers, connects and disconnects driving of each of the developers. A deceleration gear assembly is rotated according to a rotation of a gear of the developer connected to the electro-magnetic clutch. A connection unit, which is driven by the deceleration gear assembly, rotates and connects/disconnects the developing bias power supply to/from each of the developers.

Abstract: A method of conducting for transaction between a seller and a purchaser through a computer by automatically switching the auction from a bulletin mode into a chatting mode includes the steps of inputting registration information of an article for sale from a seller and then outputting schematically the registration information on information window to the purchaser; inputting bids for the article to the computer selected from the information window; calculating the beginning of the chatting mode in accordance with initiating factor for the article based on the bids and then outputting to activating the chatting mode for the article; and completing the action for the article and then selecting a successful bidder for the article.

Abstract: A waste toner collecting apparatus of an electrophotographic image forming device includes a photoreceptive drum having a first slit formed on an outer circumferential surface thereof in a lengthwise direction, through which waste toner removed from the outer circumferential surface of the photoreceptive drum by a cleaning blade contacting the outer circumferential surface thereof passes to be contained therein, and a slit opening/shutting unit which selectively opens and shuts the first silt. Thus, the image forming device can be made compact, and generation of dust can be prevented.

Abstract: A method for forming an image in an electrophotographic printer. The method includes the steps of rotating a developing roller at the same linear velocity as that of a photosensitive medium in a state where the developing roller is separated from the photosensitive medium, moving a developer so that the developing roller is in contact with the photosensitive medium, and changing the linear velocity of the developing roller to be faster than that of the photosensitive medium after contact and proceeding with the developing process, rotating the developing roller at the same linear velocity as that of the photosensitive medium after completing the developing process, and moving the developer so that the developing roller is separated from the photosensitive medium.

Abstract: A developing apparatus of an electrophotographic printer for developing an image on a photoreceptive drum includes a disc rotating independently of the photoreceptive drum at both sides of the photoreceptive drum and having at least one cam groove formed on an outer circumferential surface thereof. A developing unit includes a housing containing developer and a developing roller supported by both sidewalls of the housing and having a shaft contacting the outer circumferential surface of the disc. An elastic member is provided at a rear surface of the housing and presses the developing apparatus toward the photoreceptive drum. Thus, since the disc having at least one cam groove is provided on the outer circumferential surface and rotates independently of the photoreceptive drum, the developing roller can be detached from the photoreceptive drum at a predetermined pressure.