Abstract: A developing apparatus usable with an image forming apparatus includes a developer carrier includes a plurality of magnetic poles and a case to rotatably support the developer carrier, the case storing developer is supplied to the developer carrier, and a magnetic pole changing apparatus disposed at an end of the developer carrier to change a position of the plurality of magnetic poles with respect to the case.

Abstract: A developing apparatus usable with an image forming apparatus includes a developer carrier includes a plurality of magnetic poles and a case to rotatably support the developer carrier, the case storing developer is supplied to the developer carrier, and a magnetic pole changing apparatus disposed at an end of the developer carrier to change a position of the plurality of magnetic poles with respect to the case.

Abstract: Disclosed are a color image forming apparatus for mono color printing and a method thereof. The apparatus includes photoconductors, a charger, a development unit for forming a developer image on each of the photoconductors, a transfer unit including an image transfer member for receiving the developer image from each of the photoconductors and a transfer voltage supply member for supplying a transfer bias voltage to the image transfer member, a first cleaning unit for cleaning the photoconductors, and a control unit for controlling the photoconductors, charger, development unit and transfer unit in a mono color printing mode to form a developer image on an image area of a selected photoconductor, to transfer the formed developer image to a non-image area of the image transfer member, and to divide the transferred developer image into portions and reverse-transfer the divided portions from the image transfer member to remaining photoconductors.

Abstract: An image forming apparatus includes an image former which comprises a photosensitive body and a developing device to apply a developer to the photosensitive body, a power supply which supplies developing voltage to the developing device, a detector which detects a density of an image formed by the image former, and a controller which controls the power supply to adjust a level of the developing voltage if the detected density is out of a permissible range.

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) 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: An image forming apparatus capable of improving transfer properties, and a method for improving the transfer properties are provided by the invention. According to the method of the present invention, a surface of a photoconductive medium is electrified by applying a voltage to the photoconductive medium. An electrostatic latent image is formed on the surface of the electrified photoconductive medium. A visible image is formed by supplying toner to the surface of the photoconductive medium whereon the electrostatic latent image is formed, and the visible image of the photoconductive medium is transferred onto a paper. In the transferring step, the resistance of the paper is measured, and the image transfer is performed by maintaining a current electrifying potential if the resistance of the paper is lower than a predetermined value and lowering the current electrifying potential of the photoconductive drum if equal to or greater than a predetermined value.

Abstract: A charging voltage supply and a method for supplying a charging voltage are provided. The charging voltage supply generates a voltage and branches the generated voltage to at least one charging roller according to voltage applied to a transfer roller. Accordingly, the charging voltage supply can compensate for the charging voltage in view of the reduction of a charging potential of a photosensitive body according to the transfer voltage.

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 color image forming apparatus for mono color printing and a method thereof are disclosed.

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: 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: 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: 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) 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: 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: 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 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.