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: 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: 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: A system to replace a photosensitive unit and a transfer unit in a printer includes a frame provided in a printer body, and a locking unit which is provided in the frame and simultaneously locks and unlocks the photosensitive unit and the transfer unit that enter via an entrance of the printer body and are seated in a mounting location. The locking unit may include a rotating lever, a rotating cam, and a connection bar which connects the rotating cam to the rotating lever.

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: 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: A developer driving apparatus which drives a plurality of developing rollers via a gear chain including pivotable gears and one way gears. A reversible driving motor is coupled to a deceleration gear which directly drives a first swing drive gear and drives a second swing drive gear via an odd number of idler gears. Each swing drive gear is rotationally coupled with a respective swing gear having a center of rotation which is pivotable about a center of rotation of the respective swing drive gear. In a first position each swing gear drives one of the plurality of rollers via a respective one way gear and in a second position, each swing gear drives another of the plurality of rollers via a respective one way gear. A solenoid activated lever moves each swing gear between respective first and second positions.

Abstract: A waste toner agitator for an electrophotographic image forming apparatus comprises a plurality of protrusions protrusively formed on a top surface of a cassette, an actuator that is pivotably installed on sidewalls of the waste toner container. The actuator has a shaft that is installed inside of the waste toner container and provides a plurality of agitating wings for agitating the waste toner, and also includes a pivoting part that is installed outside of the waste toner container, is connected to the shaft, and contacts each of the protrusions. The waste toner container further comprises a plurality of elastic members that are installed opposite to the pivoting part and are placed between a plurality of supporting parts provided outside of the waste toner container, and return the actuator to its original position after the actuator contacts the protrusion and is pivoted away from its original position.

Abstract: A wasted toner storing apparatus and a dry type electrophotographic image forming apparatus using the same. The wasted toner storing apparatus includes a wasted toner container accommodating wasted toner generated during a printing process, and a dispersing member inside the wasted toner container, dispersing the wasted toner inside the wasted toner container by rotation of the dispersing member.

Abstract: A coupling apparatus capable of being connected by sliding and transferring power when being connected. The apparatus has a first coupler having a plurality of first ribs protruding at an outer circumference of a body at a regular interval and a second coupler having a connection portion to embrace and be separated from the body of the first coupler, and a plurality of second ribs protruding at an inner circumference of the connection portion, the plurality of second ribs being connected between the plurality of first ribs, wherein each of front ends of the first ribs and the second ribs have sloping sides sloped in a predetermined direction, and the first ribs include a rib having a relatively longer length than the other ribs.

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: A developer driving apparatus which drives a plurality of developing rollers via a gear chain including pivotable gears and one way gears. A reversible driving motor is coupled to a deceleration gear which directly drives a first swing drive gear and drives a second swing drive gear via an odd number of idler gears. Each swing drive gear is rotationally coupled with a respective swing gear having a center of rotation which is pivotable about a center of rotation of the respective swing drive gear. In a first position each swing gear drives one of the plurality of rollers via a respective one way gear and in a second position, each swing gear drives another of the plurality of rollers via a respective one way gear. A solenoid activated lever moves each swing gear between respective first and second positions.

Abstract: A coupling apparatus capable of being connected by sliding and transferring power when being connected . The apparatus has a first coupler having a plurality of first ribs protruding at an outer circumference of a body at a regular interval and a second coupler having a connection portion to embrace and be separated from the body of the first coupler, and a plurality of second ribs protruding at an inner circumference of the connection portion, the plurality of second ribs being connected between the plurality of first ribs, wherein each of front ends of the first ribs and the second ribs have sloping sides sloped in a predetermined direction, and the first ribs include a rib having a relatively longer length than the other ribs.

Abstract: A coupling apparatus, a development cartridge, and an electrophotographic printer having the coupling apparatus. The coupling apparatus transfers a rotation force in a connected state. The coupling apparatus has a first coupler having a cylindrical-type connection portion at an end and a spiral rib spirally protruded at an outer circumference of the connection portion; and a second coupler having a circular-type main hole depressed at an end corresponding to the connection portion, and a spiral groove formed at an inner circumference of the main hole corresponding to the spiral rib. The connection portion and the spiral rib are relatively connected with the main hole and the spiral groove by being pressed, and transmit a rotation force by being rotated together.

Abstract: A paper guide device for a duplex image forming apparatus. The paper guide device for a duplex image forming apparatus having, on a reverse paper feed path, an upper paper guide, a lower paper guide installed under the upper paper guide, and a paper cassette installed under the lower paper guide, includes a first side guide rail extended along one side of the lower paper guide and bent inwards, and a hinge guide having one side coupled to the lower paper guide by a hinge and having the opposite side curved upwards.

Abstract: An electrophotographic apparatus made up of a toner image transfer roller and a developing unit. The developing unit is provided with a developing unit shifter to shift the developing unit upwards or downwards so as to make the photoconductive drum contact or separated from the toner image transfer roller according to whether a sheet of paper is supplied between them or not. The shifter is made up of a pair of rotating cams that cause the developing unit containing the photoconductive drum to make contact with the transfer roller.