Abstract: A unit is provided to screen a photosensitive medium and an electrophotographic image forming apparatus having the same. The unit for screening a photosensitive medium includes a shutter elastically biased in a direction in which the photosensitive medium is screened. A first link, which is capable of making a straight reciprocating motion in a first direction and has a pusher pressing and pushing the shutter to expose the photosensitive medium. A second link, which is connected to the first link and is capable of making a straight reciprocating motion in a second direction not parallel to the first direction. When a door of the electrophotographic image forming apparatus is closed, the second link moves so that the first link moves in a direction in which the photosensitive medium is exposed.

Abstract: A paper feeding mechanism for an image forming apparatus includes a drive roller rotated by a first shaft driven by a motor. A press roller is supported by a second shaft which is parallel to and spaced apart from the first shaft. The press roller is pressed against the drive roller, and is driven by the drive roller. A cam pushes the second shaft (and therefore the press roller) away from the drive roller to prevent unnecessary external forces from being exerted on paper being fed through the rollers. The cam is actuated by clutching means for transferring rotating force of the first shaft to the cam to rotate the cam when it is necessary to move the press roller away from the drive roller.

Abstract: An electrophotographic image forming apparatus includes a print unit that prints an image by an electrophotographic process and has a developer cartridge having a photoreceptor drum. A door opens and closes one side of the print unit to install and remove the developer cartridge. A fixing member is selectively shifted between a first position where the developer cartridge is installed and removed and a second position where the developer cartridge is fixed to the print unit by opening and closing the door.

Abstract: A developing cartridge includes a housing having a photosensitive medium, and a protective cover movable between a first position where the protective cover covers the photosensitive medium and a second position where a part of the photosensitive medium is exposed. A guide unit guides the protective cover to prevent exceeding a range occupied by the housing when the protective cover is moved to the first and second positions.

Abstract: A high voltage switching equipment for sequentially supplying a high voltage to color developing devices, for developing an electrostatic latent image formed on a photoconductive medium of a color image forming apparatus using color toners includes high voltage applying terminals respectively formed in rear ends of fixed color developing devices contacting the photoconductive medium through a nip, a high voltage applying substrate, within which a high voltage circuit is installed, on which connector terminal strips connected to the each high voltage applying terminal are provided on one side, and on which first terminal strips connected to the high voltage circuit and second terminal strips connected to the connector terminal strips are arranged in pairs on the other side with a constant distance, and a high voltage connecting unit connecting the first terminal strips and the second terminal strips arranged on the high voltage applying substrate, so that the high voltage is supplied to a relevant developing d

Abstract: An image forming apparatus including a main body, a photoconductive unit disposed in the main body to develop an image, a transferring unit removably disposed in the main body in contact with the photoconductive unit to transfer the image from the photoconductive unit onto a recording medium, a locking/releasing unit to lock and unlock a mounting position of the transferring unit with respect to the photoconductive unit, and a checking unit to check whether the transferring unit is mounted by the locking/releasing unit. Accordingly, even if the user may inadvertently operate the image forming apparatus while not operating the locking/releasing unit so that the transferring unit and the photoconductive unit are not fixed to each other, the image forming apparatus notifies the user.

Abstract: A foreign substance prevention unit use with an electro-photographic printer is installed over a waste toner injection hole such that it closes the waste toner injection hole when a photosensitive medium is separated from a main body of the electro-photographic printer, and opens the waste toner injection hole when the photosensitive medium is installed in the main body of the electro-photographic printer. The foreign substance prevention unit is formed of an elastic material.

Abstract: A voltage supply device for developing devices of a color image forming apparatus has a printed circuit board (PCB) connected with a high voltage supply source, a plurality of fixed contact point terminals provided at one end of the respective color developing devices, and a plurality of voltage changeover units for selectively connecting the PCB and the fixed contact point terminals to selectively supply the voltage from the high voltage supply source to the respective color developing devices. With the voltage supply device, contact point changeover is enabled without having to move the developing device, by using a relay part of a relatively simple structure during the change of developing device. Accordingly, deterioration of printing quality due to shock from the contact with the developing device is avoided, and the reliability of high voltage contact point changeover is improved.

Abstract: A contact shock dampening and development nip forming apparatus for developers includes a unit to dampen a contact shock and to form a development nip installed on both ends of a developing roller to be disposed between a photosensitive body and the developing roller. Accordingly, the contact shock dampening and development nip forming apparatus absorbs shocks applied to the photosensitive body from the developing roller upon changing the developers, to thereby protect the photosensitive layer of the photosensitive body and extend the lifespan of the photosensitive body. The apparatus also maintains a thickness of the development nip to thereby obtain a steady image quality, even though the developing roller and/or the photosensitive body may be formed of solid substances.

Abstract: Provided is an image forming apparatus, which comprises a contamination prevention member that covers a top surface of a light window with one side exposed to an outside of a main body, which prevents a contamination material, such as dust, from getting onto the light window, and which a user can recognize and remove easily.

Abstract: A fusing unit used with a color laser printer includes a pair of rollers which heat and press a sheet of paper, onto which an image is transferred, and fuse the transferred image on the sheet of paper, and plastic mold bearings which rotatably support the rollers to be centered on frames.

Abstract: A waste toner transfer apparatus in an electrophotographic printer transfers waste toner removed by a cleaning unit from an image holding body where a toner image is temporarily held to a waste toner storage container. The waste toner transfer apparatus includes a duct connecting the cleaning unit and the storage container, a transfer unit installed in the duct and transferring the waste toner to the storage container, and an agitation member installed in the duct to move therein and guide the waste toner from the cleaning unit to the transfer unit.

Abstract: In an electrophotographic printer including a photosensitive drum unit having a photosensitive drum, a plurality of development units each having a developing roller, an intermediate transfer unit having a transfer belt to which an image is transferred from the photosensitive drum, a waste toner storage container to store waste toner generated at the photosensitive drum unit and the intermediate transfer unit, and a sheet transport unit which finally holds the image. The electrophotographic printer also includes first through third doors provided to mount or dismount the plurality of development units, the photosensitive drum unit and intermediate transfer unit, and the waste toner storage container, respectively, and a fourth door provided to access the sheet transport unit.

Abstract: A waste toner transfer apparatus in an electrophotographic printer for transferring waste toner removed by a cleaning unit from an image holding body, where a toner image is temporarily held, to a waste toner storage container. The waste toner apparatus includes a duct for connecting the cleaning unit and the waste toner storage container, a transfer unit installed in the duct to transfer the waste toner, a guide portion provided at an outlet of the duct to be inclined downward to guide the waste toner toward the waste toner storage container, and an agitation member installed on the guide portion and moving to prevent the waste toner from accumulating on the guide portion.

Abstract: A waste toner transfer apparatus in an electrophotographic printer to transfer waste toner removed by a cleaning unit and transferred to a waste toner storage container. The waste toner transfer apparatus includes a duct connecting the cleaning unit and the waste toner storage container, a conveying coil having a spiral shape which is installed in the duct and rotates, and an insertion member inserted in the conveying coil.

Abstract: An electrophotographic includes a main frame, a photosensitive drum unit having a photosensitive drum and vertically detachably installed on the main frame, a plurality of development units each having a developing roller and detachably installed on the main frame while sliding in a horizontal direction, and a first door openably installed for mounting or dismounting the plurality of development units.

Abstract: An electrophotographic includes a main frame, a photosensitive drum unit vertically detachably installed on the main frame and having a photosensitive drum on which an electrostatic latent image is formed, and an intermediate transfer unit vertically detachably installed on the main frame and having a transfer belt to which a toner image is transferred from the photosensitive drum, wherein the intermediate transfer unit is installed above the photosensitive drum unit.

Abstract: An electrophotographic printer including a pre-erasing unit. The pre-erasing unit includes a pre-erasing lamp to irradiate light, and a pre-transfer erasing lens to induce the light generated from the pre-transfer erasing lamp to the photosensitive drum, movably installed such that it moves to an erasure position at which the pre-transfer erasing lens is close to the photosensitive drum for erasure, and moves to a retracted position spaced apart from the photosensitive drum so as not to interfere therewith when the photosensitive drum unit is being mounted or dismounted. The pre-erasing unit may further include an elastic member to provide elasticity in a direction in which the pre-transfer erasing lens moves to the retracted position.

Abstract: A pickup error-sensing apparatus of an image forming apparatus and method therefor. The pickup error-sensing apparatus includes a sensing actuator rotatably disposed on a frame with respect to a paper cassette, displaceable when sheets of paper are loaded in the cassette, a paper sensor unit outputting a paper loading and unloading signals according to the displacement of the sensing actuator, a sensing actuator-operating unit operating the sensing actuator to allow the paper sensor unit to output the paper unloading signal when a pickup roller carries out a pickup movement, and a control unit determining whether the paper unloading signal is output when the pickup roller carries out the pickup movement, and determining occurrence of a pickup error to stop the image forming apparatus when the paper unloading signal is not output. The apparatus and method sense the pickup error generated from inadequate movement of the pick-up roller without installing a separate paper sensor.

Abstract: A fusing roller regenerating apparatus of a fusing device in an image forming apparatus includes a coating unit coating a fusing roller using a dip coating method to form a regenerated coating layer to a predetermined thickness, and a heating unit including a heating body spaced apart from a surface of the fusing roller by a predetermined distance to harden the regenerated coating layer formed on the fusing roller by the coating unit. A method of regenerating the fusing roller includes injecting a coating liquid into the coating liquid tub through a coating liquid injection portion to form the regenerated coating layer to the predetermined thickness by rotating the fusing roller after the injection of the coating liquid, hardening the regenerated coating layer using the heating body, and discharging a remaining portion of the coating liquid through the coating liquid discharging portion after the hardening of the regenerated coating layer.