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 multi-purpose feeder (MPF) for office automation (OA) machinery includes an MPF tray installed rotatably on a main body panel so that it can be opened and closed. An auxiliary stocker is rotatably installed on the tray by a hinge. An auxiliary stocker pivoting unit automatically pivots the auxiliary stocker as the MPF tray is opened and closed. Since the auxiliary stocker is automatically opened and folded when the MPF tray is opened and closed with respect to the main body, the MPF has improved user's convenience.

Abstract: Provided is a duplex printer and method of duplex printing. The duplex printer and method of printing includes a paper feeding belt that is vertically installed to form a first vertical surface; a photosensitive drum that is installed to contact the first vertical surface; and a transfer roller that is installed to contact an other surface of the first vertical surface contacting the photosensitive drum to transfer a toner image from the photosensitive drum onto a sheet of paper, which is supplied between the photosensitive drum and the paper feeding belt. A back surface feeding path of the paper is formed at an opposite side of the photosensitive drum in the paper feeding belt, and the paper is conveyed closely adhered to a surface of the paper feeding belt in the back surface feeding path of the paper.

Abstract: A color image forming device has an image forming cartridge including a cartridge frame that receives a plurality of image forming units. A movable fixing part supports at least one of the shafts of a plurality of photosensitive bodies disposed in the image forming units so that the shaft is rotatably fixed. The shafts of the other photosensitive bodies are movable and rotatable when the plurality of image forming units are received in the cartridge frame. A mounting frame receives the image forming cartridge, and has a shaft receiving part formed at a position corresponding to the ends of the shafts of the photosensitive bodies. The color image forming device accurately fixes the position of the shafts of the photosensitive bodies when the image forming cartridge is assembled in the mounting frame, thereby producing a high quality image reliably.

Abstract: An automatic belt tension apparatus of an image forming device having: a tension actuating part connected to the driving unit and operating by a driving force of a driving unit; a tension applying part to selectively apply a predetermined tension to a belt, installed with respect to the belt; and a tension releasing part to operate the tension applying part to not apply the predetermined tension to the belt, installed with respect to the tension applying part.

Abstract: Provided are a color registration sensing device to detect color registration of a color image to adjust color registration. An electrophotographic color image forming apparatus is also provided that includes a case with a door and the color registration sensing device is disposed on the case. The color registration sensing device includes at least one sensor to detect color registration of a color image, a holder including a cleaning medium which cleans the sensor while making a reciprocating movement between a first position and a second position, and an actuator to move the holder from the first position to the second position when a door of a case of an electrophotographic color image forming apparatus is closed. The holder is set to deviate from a transfer path of paper at the second position.

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 photosensitive drum protecting device for use in a color electrophotographic printer is provided. The printer, in which developing device cartridges of various colors including photosensitive drums and developing rollers are installed, and a printing path contacting the photosensitive drums is formed, includes a photosensitive drum protecting device that simultaneously exposes or protects each of the photosensitive drums. All of the photosensitive drums disposed at front end portions of the developing device cartridges are covered by just one photosensitive drum protecting device. Thus, the complexity of the printer is reduced and the printer can be made more compact.

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: Provided is a duplex printer and method of duplex printing. The duplex printer and method of printing includes a paper feeding belt that is vertically installed to form a first vertical surface; a photosensitive drum that is installed to contact the first vertical surface; and a transfer roller that is installed to contact an other surface of the first vertical surface contacting the photosensitive drum to transfer a toner image from the photosensitive drum onto a sheet of paper, which is supplied between the photosensitive drum and the paper feeding belt. A back surface feeding path of the paper is formed at an opposite side of the photosensitive drum in the paper feeding belt, and the paper is conveyed closely adhered to a surface of the paper feeding belt in the back surface feeding path of the paper.

Abstract: A photosensitive drum protecting device for use in a color electrophotographic printer is provided. The printer, in which developing device cartridges of various colors including photosensitive drums and developing rollers are installed, and a printing path contacting the photosensitive drums is formed, includes a photosensitive drum protecting device that simultaneously exposes or protects each of the photosensitive drums. All of the photosensitive drums disposed at front end portions of the developing device cartridges are covered by just one photosensitive drum protecting device. Thus, the complexity of the printer is reduced and the printer can be made more compact.

Abstract: An automatic belt tension apparatus of an image forming device having: a tension applying part to apply a predetermined tension to the belt, installed with respect to the belt; a tension releasing part to operate the tension applying part to not apply the predetermined tension to the belt, installed with respect to the tension applying part; and a tension actuating part to actuate the tension applying part to apply the predetermined tension to the belt against the tension releasing part during operation of a driving unit, installed with respect to the driving unit and the tension releasing part. According to different embodiments, the belt may be a transfer belt, an intermediate belt, or a photosensitive belt.

Abstract: An output paper stacking device includes a tray installed at a position lower than a paper discharge opening of a printing apparatus so that printed paper sheets discharged through the discharge opening can stack sequentially. Guide levers are installed to project upward through respective through slots provided in the tray for guiding both sides of the printed paper sheet, and for aligning the paper sheet at a predetermined position. A supporting unit for rotatably supporting the guide levers is provided so that one end of each guide lever can be balanced by another end of the guide lever in a state in which one end of the guide lever projects upward through the through slot of the tray. Thus, the output paper stacking device according to the present invention guides and aligns a paper sheet with guide levers having simple structures and which do not require any external driving power.

Abstract: An object insertion and separation sensing apparatus and method is provided for detecting the insertion or separation of a predetermined object into or from a main body. Included is a tactile switch installed on a circuit board provided in the main body, an elastic plate installed spaced a predetermined distance from the tactile switch and elastically pressing the tactile switch by an external force, an elastic member installed to face the tactile switch with respect to the elastic plate where the elastic plate is interposed between the elastic member and the tactile switch, one end of the elastic member is contacting the elastic plate, and a button having one end thereof contacting the other end of the elastic member and the other end thereof pressed by the object being inserted in the main body, so that the elastic member and the elastic plate are consecutively pressed to operate the tactile switch.

Abstract: An output paper stacking device includes a tray installed at a position lower than a paper discharge opening of a printing apparatus so that printed paper sheets discharged through the discharge opening can stack sequentially. Guide levers are installed to project upward through respective through slots provided in the tray for guiding both sides of the printed paper sheet, and for aligning the paper sheet at a predetermined position. A supporting unit for rotatably supporting the guide levers is provided so that one end of each guide lever can be balanced by another end of the guide lever in a state in which one end of the guide lever projects upward through the through slot of the tray. Thus, the output paper stacking device according to the present invention guides and aligns a paper sheet with guide levers having simple structures and which do not require any external driving power.

Abstract: A paper feeding apparatus of a printing device is provided. The paper feeding apparatus includes a tray releasably combined to the main body of the printing device for receiving paper. A guide plate is movably installed in the tray according to the page size of the paper, and a link is pivotally installed centering around a hinge shaft provided in the tray, to one end of which the guide plate is connected, which pivots around the hinge shaft according to the movement of the guide plate. Also, a rack is slidably installed in the tray, connected to the other end of the link, which slides according to the pivot of the link. A driving plate which rotates is provided, which engages with the rack and in which a plurality of marks corresponding to the page size of the paper are formed, and a sensor is provided for sensing the marks and the page size of the paper.

Abstract: A device for changing a resolution of a facsimile includes a pinion gear rotated by the driving power of a driving motor, a first gear for rotating a driving roller to convey a document to a contact image sensor, a second gear for changing its driving path according to a rotation direction of the pinion gear; and a third gear interlocked or separated with the first gear according to the rotation direction of the second gear. This changes the resolution. The contact image sensor reads, codes, compresses, and transmits the document data.