Patent Publication Number: US-7912403-B2

Title: Image forming apparatus with frame and pressing member

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application Nos. 10-2007-0004353 and 10-2007-0038042, respectively filed on Jan. 15, 2007 and Apr. 18, 2007 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entireties. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present general inventive concept relates to an electrophotographic image forming apparatus to improve an assembly precision of a developing cartridge with respect to a main frame. 
     2. Description of the Related Art 
     A conventional electrophotographic image forming apparatus such as a laser printer, a facsimile, a digital copy machine, etc., scans a light to a photosensitive medium charged to a predetermined electric potential to form an electrostatic latent image, develops the latent image with a predetermined colored toner, and transfers and fuses the developed image to a printing medium to print the image. 
     Referring to  FIGS. 1 and 2 , a conventional image forming apparatus includes a main frame  1  formed by means of an injection molding for reducing a number of assembling processes and lowering a manufacturing cost, and a developing cartridge  10  slidably coupled to the main frame  1 . Here, the developing cartridge  10  includes components such as a developer, a developing roller, a supplying roller, a regulating blade, etc., therein. Here, the main frame  1  is manufactured out of a resin frame by the injection molding for improving productivity and reducing the manufacturing cost, or a metal frame by a press type for reducing a mold manufacturing and improving stability of an electrical connection. 
     Also, the components of the developing cartridge  10  are supplied with power from a high voltage source (not illustrated) disposed to the main frame  1  for performing a developing process. For this, electrodes  3  and  13  are formed to facing positions of the main frame  1  and the developing cartridge  10 , and are electrically connected with each other when the developing cartridge  10  is coupled to the main frame  1 . 
     If the main frame  1  manufactured out of the resin or the metal, and the developing cartridge  10  are manufactured, there exists a design tolerance. That is, if there is a tolerance in a direction of arrow A illustrated in  FIG. 2  in the main frame  1  and the developing cartridge  10 , the tolerance has an effect on mounting of the developing cartridge  10 . 
     For example, as illustrated by an alternate long and short dash line in  FIG. 2 , if the developing cartridge  10  is designed to meet a lower limit in design tolerance and the main frame  1  is designed to meet an upper limit in design tolerance, there exists a gap between the main frame  1  and the developing cartridge  10  so that an electrical connection inferiority between the electrodes  3  and  13  can be caused. Accordingly, power is unstably supplied to the developing cartridge  10 , thereby causing a print inferiority. 
     In contrast, if the developing cartridge  10  is designed to meet an upper limit in design tolerance and the main frame  1  is designed to meet a lower limit in design tolerance, the developing cartridge  10  is incapable of being normally mounted to the main frame  1 , or being smoothly mounted to the main frame  1 . 
     Also, a gear  15  inside the developing cartridge  10  is incapable of being smoothly engaged with a gear  5  mounted to the main frame  1 . Accordingly, the developing cartridge  10  vibrates in an operation of the developing cartridge  10 , thereby causing an image inferiority such as a jitter. 
     SUMMARY OF THE INVENTION 
     The present general inventive concept provides an image forming apparatus to smoothly mount a developing cartridge to a main frame, and to stably perform an electrical transmission and a gear engagement. 
     Additional aspects and utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present general inventive concept. 
     The foregoing and/or other aspects and utilities of the present general inventive concept are achieved by providing an image forming apparatus, comprising a main frame having a first driving force transmitting part and a first electrode to supply power, a developing cartridge mounted to the main frame and having a second driving force transmitting part engaged to the first driving force transmitting part to receive a driving force, and a second electrode electrically connected with the first electrode, and a pressing member disposed to the main frame to regulate a widthwise direction movement of the developing cartridge mounted to the main frame to guide an engagement between the first and second driving force transmitting parts, and an electrical connection between the first and second electrodes. 
     The pressing member may comprise an elastic plate disposed to the main frame to elastically press the developing cartridge in a direction in which the first and second electrodes are electrically connected with each other. 
     The elastic plate may comprise an installing part coupled to the main frame, a first contact part and a second contact part to protrude toward the developing cartridge to contact with different positions of the developing cartridge. 
     The pressing member may comprise a regulating plate rotatably disposed on the main frame, and an elastic member interposed between the regulating plate and the main frame to elastically bias the regulating plate so that the developing cartridge can be positioned in a direction in which the first and second electrodes contact with each other. 
     The regulating plate may comprise a first regulating part and a second regulating part to contact with different positions of the developing cartridge. 
     The main frame may comprise resin or metal. 
     The foregoing and/or other aspects of the present general inventive concept can also be achieved by providing an image forming apparatus, comprising a main frame, a developing cartridge mounted to the main frame, and a pressing member to press the developing cartridge mounted to the main frame in a different direction from a mounting direction of the developing cartridge to regulate a widthwise direction movement of the developing cartridge. 
     The developing cartridge may comprise a photosensitive medium to sense a scanned light beam to form an image. 
     The image forming apparatus may further comprise a photosensitive medium cartridge mounted to the main frame in a predetermined direction so that a widthwise direction movement thereof can be regulated by the pressing member and having a photosensitive body to sense a scanned light beam to form an image. 
     The image forming apparatus may further comprise a waste toner container provided to a side of the developing cartridge and facing the pressing member. 
     The image forming apparatus may further comprise a first cover provided to be opened and closed to a predetermined position of the main frame which corresponds to a mounting position of the developing cartridge. 
     The image forming apparatus may further comprise a second cover provided to be opened and closed to a predetermined position of the main frame, wherein the pressing member is formed to the second cover to elastically press the developing cartridge. 
     The pressing member may comprise an installing part coupled to the second cover, and a first contact part and a second contact part to protrude toward the developing cartridge to contact with different positions of the developing cartridge. 
     The pressing member may comprise a regulating plate rotatably disposed to the second cover, and an elastic member interposed between the regulating plate and the second cover to elastically bias the regulating plate toward the developing cartridge. 
     The regulating plate may comprise a first regulating part and a second regulating part to contact with different positions of the developing cartridge. 
     The foregoing and/or other aspects of the present general inventive concept can also be achieved by providing an image forming apparatus, comprising a main frame, a developing cartridge to be mounted inside the main frame, and a developing cartridge moving device to shift the developing cartridge in a direction to regulate a widthwise direction movement thereof prior to a beginning of a printing process. 
     The image forming apparatus may further comprise first electrodes mounted inside the main frame to supply power to the developing cartridge, and second electrodes mounted on a side portion of the developing cartridge, such that the developing cartridge is shifted by the moving device to establish a secure electrical connection between the first electrodes and the second electrodes. 
     The image forming apparatus may further comprise a first driving force transmitting part mounted inside the main frame, a second driving force transmitting part mounted on the developing cartridge to engage with the first driving force transmitting part to receive a driving force to perform a printing operation. 
     The first driving force transmitting part and the second driving force transmitting part may be gears which each have a thickness corresponding to a potential shifting distance of the developing cartridge. 
     The main frame may comprise a first cover to open to install the developing cartridge inside the main frame or uninstall the developing cartridge from the main frame. 
     The main frame may further comprise a second cover to which the developing cartridge moving device is attached. 
     The second cover may open to install the developing cartridge inside the main frame or uninstall the developing cartridge from the main frame. 
     The second cover may open to install a waste toner container inside the main frame or uninstall the waste toner container from the main frame. 
     The image forming apparatus may further comprise a photosensitive medium cartridge comprising a photosensitive medium to form an electrostatic latent image on a printing medium. 
     The main frame may comprise a first cover to open to install the developing cartridge inside the main frame or uninstall the developing cartridge from the main frame, and a second cover to open to install the photosensitive medium cartridge inside the main frame or uninstall the photosensitive medium cartridge from the main frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view illustrating a main part of a conventional image forming apparatus; 
         FIG. 2  schematically illustrates a coupling state of a developing cartridge with respect to a main frame of the conventional image forming apparatus; 
         FIG. 3  is an exploded perspective view illustrating a main part of an image forming apparatus according to an exemplary embodiment of the present general inventive concept; 
         FIG. 4A  is a schematic partial sectional view illustrating a main frame of the image forming apparatus according to an exemplary embodiment of the present general inventive concept; 
         FIG. 4B  is a schematic partial sectional view illustrating a coupling state of a developing cartridge with respect to the main frame of the image forming apparatus according to an exemplary embodiment of the present general inventive concept; 
         FIG. 5  is an exploded perspective view illustrating a main part of an image forming apparatus according to another exemplary embodiment of the present general inventive concept; 
         FIG. 6A  is a schematic partial sectional view illustrating a main frame of the image forming apparatus according to another exemplary embodiment of the present general inventive concept; 
         FIG. 6B  is a schematic partial sectional view illustrating a coupling state of a developing cartridge with respect to the main frame of the image forming apparatus according to another exemplary embodiment of the present general inventive concept; 
         FIG. 7  is an exploded perspective view illustrating a main part of an image forming apparatus according to another exemplary embodiment of the present general inventive concept; and 
         FIG. 8  is an exploded perspective view illustrating a main part of an image forming apparatus according to another exemplary embodiment of the present general inventive concept. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The exemplary embodiments are described below so as to explain the present general inventive concept by referring to the figures. 
     As illustrated in  FIGS. 3 through 4B , an image forming apparatus according to an exemplary embodiment of the present general inventive concept includes a main frame  30 , a developing cartridge  40  mounted in the main frame  30 , and a pressing member  50  to regulate a widthwise direction movement of the developing cartridge  40  mounted in the main frame  30 . The widthwise direction movement may be performed before a printing operation is begun. The printing operation begins after the image forming apparatus receives information regarding an image to be printed. Therefore, the widthwise direction movement may be performed as compensation regarding slight deviations in a structure of either the developing cartridge  40  or the main frame  30  upon installation of the developing cartridge  40  in the main frame  30 . 
     In the exemplary embodiment of  FIGS. 3 through 4B , the main frame  30  and the developing cartridge  40  include a mold object manufactured by an injection molding process to raise productivity, reduce a number of assembling processes, and lower a manufacturing cost. 
     Elements comprised in the image forming apparatus such as the developing cartridge  40 , a photosensitive medium to form an electrostatic latent image on a printing medium, a light scanning unit, a transferring unit, a fusing unit and a feeding and discharging unit, are mounted in the main frame  30 . Also, a driving force transmitting part and a power supplying source to supply a driving force and power to the elements are mounted in the main frame  30 . 
     More specifically, a first driving force transmitting part  33  to transmit the driving force to the developing cartridge  40 , and a first electrode  35  to supply the power to the developing cartridge  40  are installed in the main frame  30 . 
     The developing cartridge  40  is mounted in the main frame  30  by a sliding coupling. To perform the sliding coupling, a coupling guiding protrusion  41  is formed to the opposite inner surfaces of the developing cartridge  40 , and a guiding groove  31  is provided to an inner surface of the main frame  30  to guide the coupling guiding protrusion  41 . 
     Also, the developing cartridge  40  may include elements such as a developer, a developing roller to apply developer corresponding to the electrostatic latent image to the printing medium, a supplying roller, a regulating blade, the photosensitive medium, etc., therein. Also, to drive the inner elements, the developing cartridge  40  includes a second driving force transmitting part  43  to engage with the first driving force transmitting part  33  to receive the driving force, and a second electrode  45  electrically connected with the first electrode  35 . 
     The second electrode  45  faces the first electrode  35  when the developing cartridge  40  is completely mounted in the main frame  30 , and is electrically connected with the first electrode  35  during coupling of the developing cartridge  40  with respect to the main frame  30 . Accordingly, the pressing member  50  prevents a potential electrical connection inferiority between the first and second electrodes  35  and  45  due to a tolerance designed during a manufacturing process of the main frame  30  and the developing cartridge  40 . 
     The pressing member  50  is disposed inside the main frame  30 , and regulates a widthwise direction movement of the developing cartridge  40  mounted in the main frame  30 . Accordingly, the pressing member  50  guides both the engagement between the first driving force transmitting part  33  and the second driving force transmitting part  43 , as well as the electrical connection between the first electrode  35  and the second electrode  45 . 
     In the exemplary embodiment of  FIGS. 3 through 4B , the pressing member  50  can include an elastic plate  150  to elastically press the developing cartridge  40  in an electrical connecting direction between the first and second electrodes  35  and  45 . The elastic plate  150  includes an installing part  151 , a first contact part  153  and a second contact part  155 . The installing part  151  is a part to couple the elastic plate  150  to an inner surface of the main frame  30 . Accordingly, the elastic plate  150  is coupled to the inner surface of the main frame  30  by a screw  157  as illustrated in  FIG. 4A , or may be coupled thereto by an adhesive, a hook member, an insert molding process, or other known coupling means in the art. The pressing member  50  is not limited to the elastic plate  150 , and can include any type of developing cartridge moving device to move the developing cartridge  40  in a manner described herein to perform the intended operations of the present general inventive concept. For example, pins, magnets, pistons, air-pressure devices, and hydraulic devices which can move the developing cartridge  40  in the intended direction can be used alternatively. 
     The first and second contact parts  153  and  155  protrude toward the developing cartridge  40 , and respectively contact different parts of the developing cartridge  40 . That is, referring to  FIG. 4B , the first contact part  153  contacts a front end part  40   a  side of the developing cartridge  40 , and the second contact part  155  contacts a rear end part  40   b  side of the developing cartridge  40 . Accordingly, the developing cartridge  40  mounted in the main frame  30  can be prevented from tilting, that is, being inclined inside the main frame  30 . Also, first and second end parts  153   a  and  155   a , respectively, of the first and second contact parts  153  and  155  are free ends, and can slide in a direction away from the installing part  151  by contacting with an inner surface  30   a  of the main frame  30  when the developing cartridge  40  is elastically pressed by the first and second contact parts  153  and  155 . Accordingly, the first and second contact parts  153  and  155  elastically press the developing cartridge  40  by an elastic bias force between the free ends  153   a  and  155   a  and the main frame  30 , so that the widthwise direction movement of the developing cartridge  40  can be regulated. 
     As illustrated in  FIG. 4A , since the main frame  30  is manufactured by the injection molding, a tolerance of an inner width W 1  of the main frame  30  is greater than that of a main frame manufactured by a press process. Similarly, as illustrated in  FIG. 4B , a tolerance of a width W 2  of the developing cartridge  40  is also greater than that of a main frame manufactured by a press process. In contrast, values of widths W 1  and W 2  are determined within allowable tolerance ranges so that the developing cartridge  40  can be smoothly mounted in the main frame  30 , although the width W 1  of the main frame  30  is minimized, and the width W 2  of the developing cartridge  40  is maximized. That is, although a forming tolerance is taken into consideration, a design tolerance is determined where W 1  is wider than W 2 . 
     Also, the elastic plate  150  may be disposed to elastically press in a contacting direction of the first and second electrodes  35  and  45  when the elastic plate  150  is mounted inside the main frame  30 . Accordingly, a margin due to tolerance between the main frame  30  and the developing cartridge  40  is formed at the elastic plate  150  side. 
     The first and second diving force transmitting parts  33  and  43  may include gears engaged with a predetermined gear ratio. Also, although the first and second driving force transmitting parts  33  and  43  deviate from each other as illustrated in  FIG. 4B , the driving force can be smoothly transmitted by adjusting a gear width of the first and/or second driving force transmitting parts  33  and  43 . 
     Referring to  FIGS. 5 through 6B , an image forming apparatus according to another exemplary embodiment of the present general inventive concept includes a main frame  30 , a developing cartridge  40  mounted inside the main frame  30 , and a pressing member  50  to regulate a widthwise direction movement of the developing cartridge  40  mounted in the main frame  30 . Accordingly, the main frame  30 , a guiding groove  31 , and the developing cartridge  40  may have the same configurations as the image forming apparatus according to the exemplary embodiment of  FIGS. 3 through 4B  of the present general inventive concept. 
     In the exemplary embodiment of  FIGS. 5 through 6B , the pressing member  50  includes a regulating plate  251  installed to the main frame  30  to change a position of the developing cartridge  40  elastically, and an elastic member  255  to press the regulating plate  251  by elastic bias. 
     The regulating plate  251  may include a first regulating part  252  and a second regulating part  254  to contact various parts of the developing cartridge  40 . That is, the first regulating part  252  contacts a front end side of the developing cartridge  40 , and the second regulating part  254  contacts a rear end side of the developing cartridge  40 . Accordingly, the developing cartridge  40  mounted in the main frame  30  can be prevented from tilting, that is, being inclined inside the main frame  30 . Also, the regulating plate  251  is coupled to an inner surface  30   a  of the main frame  30  by a screw  259  as illustrated in  FIG. 5 , or may be coupled to the main frame  30  by a hinge (not illustrated). 
     The elastic member  255  may include a first elastic member  256  and a second elastic member  258  to elastically support the first and second regulating parts  252  and  254 , respectively. The elastic member  255  is interposed between the regulating plate  251  and the main frame  30 , and elastically biases the regulating plate  251  in a direction in which a first electrode  35  and a second electrode  45  are electrically connected. Accordingly, although there is a forming tolerance when the main frame  30  and the developing cartridge  40  are manufactured by the injection molding process, the first electrode  35  and the second electrode  45  can electrically contact each other when the regulating plate  251  and the elastic member  255  act together to move the developing cartridge  40  in a widthwise direction, thereby preventing an electrical connection inferiority. Also, although first and second driving force transmitting parts  33  and  44  deviate from each other in a widthwise direction due to a forming tolerance in configuring the first and second diving force transmitting parts  33  and  44 , the driving force can be smoothly transmitted by adjusting the width of the first and/or second diving force transmitting parts  33  and  44 . 
     In the exemplary embodiment of  FIGS. 5 through 6B , the elastic member  255  may include a compression spring interposed between the regulating plate  251  and the main frame  30 . Alternatively, the elastic member  255  may include a torsion spring, an extension spring or other known springs in the art. Also, the regulating plate  251  may be provided as an elastic plate without the elastic member  255 , as necessary. 
     Referring to  FIG. 7 , an image forming apparatus according to another exemplary embodiment of the present general inventive concept includes a main frame  300 , a developing cartridge  330 , and a pressing member  350  to press the developing cartridge  330  mounted in the main frame  300  in a lengthwise direction of a developing roller  335  to regulate a widthwise direction movement of the developing cartridge  330 . The developing cartridge  330  includes a photosensitive medium  331  to sense a scanned light beam to form an image, and the developing roller  335  and a developer (not illustrated) to develop the image formed by the photosensitive medium  331 . The developing cartridge  330  is mounted in the main frame  300  in a perpendicular direction to a lengthwise direction of the developing roller  335 . Accordingly, the developing cartridge  330  may have the same configuration as the image forming apparatus according to the exemplary embodiment of  FIGS. 3 through 4B  of the present general inventive concept. 
     Also, as illustrated in  FIG. 7 , the developing roller  335  is used as a developing member. Alternatively, a developing belt may be employed therefor as necessary. Also, the image forming apparatus according to the embodiment of  FIG. 7  of the present general inventive concept may further include a waste toner container  340  to face the pressing member  350 , and to be detachably coupled to one side of the developing cartridge  330 . The waste toner container  340  is a container to collect a waste toner remaining after the developing process finishes. The waste toner container  340  may be separable from the main frame  300  without separating the developing cartridge  330  from the main frame  300 , or may be separable according to mounting and detachment of the developing cartridge  330  or a photosensitive medium cartridge  460  illustrated in  FIG. 8 . 
     Also, the image forming apparatus according to the exemplary embodiment of  FIG. 7  may further include a first cover  310  and a second cover  320  disposed to a predetermined position of the main frame  300  to be opened and closed. The first cover  310  is formed to open and close in a direction of arrow C, in which the developing cartridge  330  is mounted. When the first cover  310  is opened, the developing cartridge  330  may be mounted in and/or detached from the main frame  300 . The second cover  320  is formed on the main frame  300  to open and close in a direction of arrow B to be positioned to one side of the developing cartridge  330  mounted inside the main frame  300 . Accordingly, if the second cover  320  is opened, the waste toner container  340  detachably mounted to a side of the developing cartridge  330  can be mounted in and/or detached from the main frame  300 . Accordingly, the first and second covers  310  and  320  may be respectively coupled to the main frame  300  by a hinge to rotate about the hinge. 
     The pressing member  350  is formed on the second cover  320  to elastically press the developing cartridge  330  in the lengthwise direction of the developing roller  335 . The pressing member  350  includes an installing part  351  coupled to the second cover  320 , and first and second contact parts  353  and  355 . The installing part  351  is a part to couple the pressing member  350  to an inner side of the second cover  320 , and may be coupled to the inner side of the second cover  320  by a screw as illustrated in  FIG. 7 , or by an adhesive, a hook member, an insert molding process, or other known coupling components in the art. 
     The first and second contact parts  353  and  355  protrude toward the developing cartridge  330 , and respectively contact with different parts of the developing cartridge  40  or the waste toner container  340 . Accordingly, the developing cartridge  330  mounted in the main frame  300  can be prevented from being inclined inside the main frame  300 . Here, the pressing member  340  may have the same configuration as the pressing member  50  illustrated in  FIG. 3  of the image forming apparatus according to the exemplary embodiment of  FIGS. 3 through 4B  of the present general inventive concept. 
     With this configuration, if the developing cartridge  330  is mounted in the direction of the arrow C through an area opened by the first cover  310 , the waste toner container  340  is mounted in the direction of the arrow B through a side of the developing cartridge  330  opened by the second cover  320 , and the first and second covers  310  and  320  are closed, the pressing member  350  formed to the second cover  320  presses the waste toner container  340 , and the waste toner container  340  is pressed so that the developing cartridge  300  coupled with the waste toner container  340  can be pressed. Accordingly, although there is a forming tolerance when the main frame  300  and the developing cartridge  330  are manufactured by the injection molding, the electrodes  35  and  45  illustrated in  FIG. 4B , which are positioned to an opposite position to the pressing member  350  can be stably electrically connected with each other. 
     The pressing member  350  may include a regulating plate having a configuration as illustrated in  FIGS. 5 to 6B  to be rotatably disposed on the second cover  320 , and an elastic member interposed between the regulating plate and the second cover  320  to elastically bias the regulating plate toward the developing cartridge  330 . The regulating plate may include a first regulating part and a second regulating part to contact different positions of the developing cartridge  330 . The pressing member  350  may have the same configuration as the pressing member  50  of the image forming apparatus according to the exemplary embodiment of  FIGS. 5 through 6B  of the present general inventive concept. 
     In the exemplary embodiment of  FIG. 7 , the first and second covers  310  and  320  are formed on the main frame  300 , and the waste toner container  340  is detachably mounted in the main frame  300  through the second cover  320 . However, various changes may be employed to the exemplary embodiment of  FIG. 7  without departing from the principles and spirit of the present general inventive concept. For example, the pressing member  350  provided to an inner surface of the second cover  320  may directly press a side of the developing cartridge  330  without the waste toner container  340  being detachable. 
     Also, the pressing member  350  may have a configuration to press and release to interlock with or detach from the second cover  320 . That is, a link unit (not illustrated) may be separately provided. If the second cover  320  is closed, the pressing member  350  moves to a pressing position, and if the second cover  320  is opened, the pressing member  350  moves to a releasing position. 
     Referring to  FIG. 8 , an image forming apparatus according to another exemplary embodiment of the present general inventive concept includes a main frame  300 , a developing cartridge  430 , a photosensitive medium cartridge  460 , and a pressing member  350  to press the developing cartridge  430  mounted in the main frame  300  in a lengthwise direction of a developing roller  435  to regulate a widthwise direction movement of the developing cartridge  430 . 
     In comparison with the image forming apparatus according to the exemplary embodiment of  FIG. 7  of the present general inventive concept, the image forming apparatus according to the exemplary embodiment of  FIG. 8  distinctively includes the separate photosensitive medium cartridge  460  excluding a photosensitive medium from the developing cartridge  430 . 
     The photosensitive medium cartridge  460  includes a photosensitive medium  461  to sense a scanned light beam to form an image, and a cleaning blade (not illustrated) to remove a toner remaining on the photosensitive medium  461 . Accordingly, a mounting direction of the photosensitive medium cartridge  460  may be determined independent of a mounting direction of the developing cartridge  430 . That is, the photosensitive medium cartridge  460  may be mounted in a direction of arrow B perpendicular to the mounting direction of the developing cartridge  430 , or in a direction of arrow C, which is the same direction as the mounting direction of the developing cartridge  430 . Also, the photosensitive medium cartridge  460  may be detachably mounted with respect to the main frame  300 , or may be securely coupled inside the main frame  300 . 
     Since the photosensitive medium cartridge  460  has a longer life span than the developing cartridge  430 , a replacement period of the developing cartridge  430  is relatively short. Accordingly, if the developing cartridge  430  and the photosensitive medium cartridge  460  are separately provided, as in the exemplary embodiment of  FIG. 8 , the replacement period can be independently determined, thereby reducing an unnecessary expendable replacement of the photosensitive medium cartridge  460 . 
     As illustrated in  FIG. 8 , if the photosensitive medium cartridge  460  is configured to be mounted in the direction of the arrow B, a second cover  420  has a bigger width than the second cover  230  according to the exemplary embodiment of  FIG. 7  of the present general inventive concept. 
     Since regulation of the widthwise direction movement of the developing cartridge  430  is required relatively more frequently than regulation of the movement of the photosensitive medium cartridge  460  due to a replacement period difference, the position of a regulating member  320  is determined with a consideration of a mounting position of the developing cartridge  430 . In addition to regulating the developing cartridge  430 , the regulating member  320  contacts to the photosensitive medium cartridge  460  at a predetermined position to regulate the widthwise direction movement of the photosensitive medium cartridge  460 , thereby preventing the photosensitive medium cartridge  460  from being inclined inside the main frame  300 . 
     As described above, an image forming apparatus according various embodiments to the present general inventive concept can prevent a driving force transmission inferiority and a power supplying inferiority due to a forming tolerance generated when a main frame and a developing cartridge are manufactured by an injection molding process. 
     That is, by designing an inner width of the main frame wider than a width of the developing cartridge with a prediction of deformations from injection conditions of the main frame and the developing cartridge, and from a usage environment, a jitter problem corresponding to an image and a noise problem generated in the conventional developing cartridge forcedly mounted due to insufficient marginal space between the main frame and the developing cartridge can be fundamentally solved. 
     Also, since the pressing member prevents an electrical connection inferiority between the developing cartridge and the main frame, the power supplying inferiority can be prevented. Also, by determining the widths of first and second driving force transmitting parts with consideration of a forming margin, a driving force transmission can be smoothly accomplished. 
     Also, although a separate cover is provided to open and close in a side, the present general inventive concept may be applied thereto, thereby efficiently pressing the developing cartridge. 
     Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.