Abstract: A driving apparatus includes a driving gear connected to a driving motor, a driven gear engaged with the driving gear, and a driving force coupling part coupling the driving gear and the driven gear to not move with respect to each other. The driving force coupling part includes an axle distance maintaining member to maintain a substantially constant distance between axes of the driving gear and the driven gear. The driving apparatus couples the driving gear and the driven gear to not move with respect to each other when a driving force is transmitted from the driving gear to the driven gear, thereby maintaining a substantially uniform distance between axes of the driving gear and the driven gear. Accordingly, a driven gear shaft is substantially prevented from changing position and deformation of a process cartridge is substantially prevented due to a driving torque of the driving gear and a load torque of the driven gear.

Abstract: An image forming apparatus capable of reducing a space required to install a transfer unit to achieve a compact body size. The image forming apparatus can include a body, a frame installed in the body, a transfer unit installed inside the frame, and a waste toner recovery device to recover waste toner collected from the transfer unit. The waste toner recovery device can include a first delivery unit to deliver the waste toner in a first direction, and a second delivery unit to deliver the waste toner, delivered from the first delivery unit, in a second direction. The second delivery unit can be movably installed to the frame and can be coupled to or detached from the first delivery unit via movement thereof.

Abstract: An image forming apparatus and a transfer device thereof are disclosed. The transfer device includes an intermediate transfer belt, at least one intermediate transfer belt roller to maintain tension in the intermediate transfer belt, transfer rollers to press the intermediate transfer belt to image carriers and a state changing device to change an operating state between at least a first state, in which the tension in the intermediate transfer belt is released, and a second state, in which select ones of the transfer rollers are separated from the intermediate transfer belt.

Abstract: An image forming apparatus capable of preventing simultaneous delivery of two sheets of paper when they are supplied from a paper supply device, thereby improving operational reliability of the paper supply device. The image forming apparatus includes a body incorporating a printing device, a first paper supply unit, in which first paper is loaded, a second paper supply unit, on which second paper is disposed, at least one feed roller to deliver the second paper disposed on the second paper supply unit, a pickup roller to pick up the first paper from the first paper supply unit, and a pickup pad, which is located at a first position to contact the pickup roller when the pickup roller picks up the first paper from the first paper supply unit, and which is located at a second position spaced apart from the pickup roller when the second paper disposed on the second paper supply unit is delivered by the feed roller.

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 fusing unit for an image forming apparatus, including a heating roller to apply heat to a printable medium; a first pressing roller facing the heating roller so as to press the printable medium against the heating roller; a second pressing roller disposed in front of the first pressing roller in a proceeding direction of the printable medium press the printable medium against the heating roller; and a driving unit to transmit a rotation force to the second pressing roller so that a surface linear speed of the second pressing roller is greater than a surface linear speed of the heating roller.

Abstract: A developer-driving device and an image forming apparatus having the same are provided. The developer-driving device includes a photosensitive drum-driving unit that rotates a photosensitive drum and a developing roller-driving unit that rotates a developing roller. Each of the photosensitive drum-driving unit and the developing roller-driving unit includes a one-way power transmission unit. The one-way power transmission unit idles when a developer is being mounted on a main body and transmits power to the photosensitive drum and the developing roller after the developer is mounted on the main body.

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 image forming apparatus capable of increasing the speed of successively discharging printed printing media in order to increase the overall print speed and a control method thereof. The image forming apparatus includes a first discharge roller to feed printed printing medium rearward from a print unit disposed at an inner front portion of a main body, a reverse roller to reverse a moving direction of the printed printing medium fed from the first discharge roller from a rear to a front of the main body, a second discharge roller to discharge the printed printing medium whose moving direction is reversed outside, and an intermediate discharge roller unit which is provided between the first discharge roller and the reverse roller, the intermediate discharge roller unit including a main roller, a sub discharge roller and a sub supply roller which are in contact with the main roller.

Abstract: An image forming apparatus including: a main body including a manipulating unit which manipulates the power transmission unit, a driving component having a driving assembling member which is disposed in a direction of a rotational driving axial line; a developing device which has a driven assembling member capable of being engaged with and disengaged from the driving assembling member along the direction of the rotational driving axial line; a power transmission unit which is disposed between the driving assembling member and the driven assembling member and enables at least one of the driving assembling and the driven assembling member is moveable in the direction of the rotational driving axial line.

Abstract: An image forming apparatus includes a developing unit to form an image using a developing agent on one side of a printing medium transported along a simplex printing path, a fixing unit to fix the developing agent on the printing medium, a discharging roller to discharge the printing medium that passes the fixing unit, and a first driving source to drive the developing unit, the fixing unit and the discharging roller.

Abstract: An image forming apparatus includes a shaft, a shaft support portion rotatably supporting the shaft, a shaft gear provided at an end portion of the shaft in a lengthwise direction, and a first gear engaged with the shaft gear and rotating the shaft gear. The rotation of the first gear applies a force acting toward the shaft support potion and the shaft contacts the shaft support portion by the force during rotation so that vibration of the shaft is restricted. An image forming apparatus includes a case having a door that can be opened and closed, a shaft provided in the case, a shaft support portion rotatably supporting the shaft, a shaft gear provided at an end portion of the shaft in a lengthwise direction, and a first gear engaged with the shaft gear and rotating the shaft gear. The first gear is engaged with the shaft gear when the door is closed and disengaged from the shaft gear when the door is open.

Abstract: A door shock absorber is provided to absorb noise and shock when a door is opened, and an image forming apparatus employing the same. The door shock absorber includes a first guide rail included in a door mounted on a case used as an outer covering. A first spring is contained by the first guide rail. A link has a first end hingedly connected to the inside of the case, and a second end connected to the first guide rail and able to move in the direction of the first guide rail. When the door is opened, the second end of the link moves in the direction of the first guide rail and compresses the first spring.

Abstract: An image forming apparatus includes plurality image carriers sequentially arranged, a conveying belt, which conveys a print medium onto which color-separated images formed on the plurality of image carriers are overlapped, and a plurality of image transfer rollers installed to respectively correspond to the plurality image carriers. The conveying belt is interposed between the image transfer rollers and the image carriers. At least one of the plurality image transfer rollers is arranged to be compressed with a pressure higher than those applied to the other image transfer rollers against the image carriers.

Abstract: An electrophotographic image forming apparatus has a development unit with a photoconductor. A transport belt conveys a printing medium onto which a toner image is transferred from the photoconductor. A separator is disposed inside the transport belt, and is capable of extending outwardly to push the printing medium to separate the printing medium from the transport belt after transferring the toner image.

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 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: 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 tandem color image forming apparatus includes a plurality of photosensitive bodies driven by one driving source and having a shaft gear, and power transmission members engaged with the shaft gears of the plurality of the photosensitive bodies to transmit a driving force generated from the driving source to each of the plurality of the photosensitive bodies. At least one color registration compensation unit is disposed between the power transmission members. The color image forming apparatus employs the color registration compensation unit so that each photosensitive body can be synchronized and registration errors can be minimized.

Abstract: A driving apparatus includes a driving gear connected to a driving motor, a driven gear engaged with the driving gear, and a driving force coupling part coupling the driving gear and the driven gear to not move with respect to each other. The driving force coupling part includes an axle distance maintaining member to maintain a substantially constant distance between axes of the driving gear and the driven gear. The driving apparatus couples the driving gear and the driven gear to not move with respect to each other when a driving force is transmitted from the driving gear to the driven gear, thereby maintaining a substantially uniform distance between axes of the driving gear and the driven gear. Accordingly, a driven gear shaft is substantially prevented from changing position and deformation of a process cartridge is substantially prevented due to a driving torque of the driving gear and a load torque of the driven gear.