Patent Publication Number: US-9897937-B2

Title: Development cartridge and electrophotographic image forming apparatus using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Korean Patent Application No. 10-2015-0185095, filed on Dec. 23, 2015, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field 
     The disclosure is related to an electrophotographic image forming apparatus for forming an image onto a recording medium in an electrophotographic manner, and a development cartridge capable of being detachably attached to the electrophotographic image forming apparatus. 
     2. Description of the Related Art 
     An electrophotographic image forming apparatus operating in an electrophotographic manner prints an image onto a recording medium by forming a visible toner image on a photosensitive body by supplying a toner to an electrostatic latent image formed on the photosensitive body, transferring the toner image to the recording medium, and fixing the transferred toner image to the recording medium. 
     A development cartridge is an assembly of elements for forming the visible toner image. The development cartridge is detachably attached to a main body of the image forming apparatus and is a consumable item to be replaced when its service life is over. In a development cartridge using a contact development manner, a developing roller and the photosensitive body contact each other and thus form a development nip. 
     When a long time elapses after the development nip is formed, the developing roller may be deformed and the photosensitive body may be damaged. The deformation of the developing roller and the damage of the photosensitive body may cause a change of the development nip, which reduces the image quality. 
     SUMMARY 
     Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure. 
     Provided are a development cartridge having a simple development nip detachment structure, and an electrophotographic image forming apparatus employing the development cartridge. 
     Provided are a development cartridge having a durability-improved development nip detachment structure, and an electrophotographic image forming apparatus employing the development cartridge. 
     Provided are a development cartridge having a driving noise-reduced development nip detachment structure, and an electrophotographic image forming apparatus employing the development cartridge. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosed embodiments. 
     According to an aspect of an embodiment, a development cartridge for an image forming apparatus may includes a photosensitive unit comprising a photosensitive drum; a developing unit comprising a developing roller configured to contact the photosensitive drum so as to form a development nip, the developing unit coupled to the photosensitive unit to be rotatable; a driving gear configured to drive at least one of the developing roller and the photosensitive drum, and configured to rotate in a first direction or a second direction opposite the first direction; a driving member positioned coaxially with the driving gear and configured to be rotated by the driving gear; a first one-way clutch configured to connect the driving member with the driving gear when the driving gear rotates in the second direction; and a first moving member configured to be connected to the driving member so as to move between a first location to rotate the developing unit to form the development nip and a second location to rotate the developing unit to release the development nip. 
     The driving gear may be configured to be rotated in the first direction during a printing operation, and to be rotated in the second direction during a non-printing operation. 
     The driving member may include pinion gear parts, and the first moving member comprises rack gear parts to be engaged with the pinion gear parts. 
     When the first moving member moves from the first location to the second location, the first moving member may rotate the developing unit in a direction to cause the development nip to be released, and when the first moving member moves from the second location to the first location, the first moving member may allow the developing unit to rotate in a direction to cause the development nip to be formed. 
     The development cartridge may further include an elastic member configured to provide an elastic force by which the developing unit rotates to form the development nip, and wherein, when the driving gear rotates in the first direction, the first moving member may move from the second location to the first location due to the elastic force of the elastic member. 
     The driving gear and the driving member may be disposed at the development nip, and when the first moving member moves from the first location to the second location, the first moving member may move the photosensitive unit by contacting a contact part of the photosensitive unit. 
     The driving gear and the first moving member may be disposed at the photosensitive unit, and when the first moving member moves from the first location to the second location, the first moving member may move the developing unit by contacting a contact part of the developing unit. 
     A speed reducer may be disposed between the driving gear and the driving member. The speed reducer comprises a planetary reducer. 
     The planetary reducer may include a sun gear configured to be rotated by the driving gear, and a plurality of planet gears configured to be engaged with the sun gear and to be rotatably mounted at the driving member, and the driving gear and the sun gear may be connected to each other by the first one-way clutch. 
     The photosensitive unit may include a first rotational member comprising the photosensitive drum, the developing unit may include a second rotational member comprising the developing roller, and the driving gear and the driving member may be mounted on a rotation axis of one of the first rotational member and the second rotational member. 
     The driving gear may be rotatably mounted on a rotation axis of the developing roller, and the development cartridge may further include a driving bush coupled to the rotation axis of the developing roller, and a second one-way clutch configured to connect the driving gear with the driving bush when the driving gear rotates in the first direction. 
     The photosensitive unit may include a first rotational member comprising the photosensitive drum, the developing unit may include a second rotational member comprising the developing roller, and the driving gear and the driving member may be mounted on an axis other than rotation axes of the first rotational member and the second rotational member. 
     The development cartridge may further include a charging roller configured to form a charging nip by contacting the photosensitive drum and to charge the photosensitive drum; a second elastic member configured to apply an elastic force to the charging roller in a direction to cause the charging roller to contact the photosensitive drum; and a second moving member disposed at the photosensitive unit so as to be moved, by the driving member, between a charging position to form the charging nip and a non-charging position to space the charging roller apart from the photosensitive drum. 
     The second moving member may be configured to move from the charging position to the non-charging position when the first moving member is moved from the first location to the second location. 
     The development cartridge may further include an extending part disposed at the developing unit and configured to move the second moving member to the non-charging position when the first moving member is moved from the first location to the second location. 
     The development cartridge may further include a third elastic member configured to apply an elastic force to the second moving member in a direction to cause the second moving member to return to the charging position when the first moving member is moved from the second location to the first location. 
     According to an aspect of another embodiment, an electrophotographic image forming apparatus may include: a main body, and the development cartridge above, the development cartridge capable of being detachably attached to the main body. 
     The electrophotographic image forming apparatus may further include a driving motor disposed at the main body and configured to drive the photosensitive drum and the developing roller; and a second one-way clutch disposed between the driving motor and the photosensitive drum so as to connect the driving motor with the photosensitive drum when the driving gear rotates in the first direction. 
     The electrophotographic image forming apparatus may further include a first driving motor disposed at the main body and configured to drive the photosensitive drum; and a second driving motor disposed at the main body and configured to drive the developing roller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects 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 a schematic configuration diagram illustrating an electrophotographic image forming apparatus, according to an embodiment; 
         FIG. 2  illustrates a side view of a development cartridge shown in  FIG. 1 , illustrating a state of the development cartridge in which a photosensitive drum and a developing roller are located at a development position; 
         FIG. 3  illustrates a side view of the development cartridge shown in  FIG. 1 , illustrating a state of the development cartridge in which the photosensitive drum and the developing roller are located at a non-development position; 
         FIG. 4  illustrates an example of a driving connection structure of rotational members of a developing unit and a photosensitive unit; 
         FIG. 5  is a schematic configuration diagram illustrating a structure in which a first moving member is shifted to a first location or a second location, according to an embodiment; 
         FIG. 6  is a diagram illustrating a one-way clutch that selectively connects a driving member with the driving gear, according to an embodiment; 
         FIG. 7  is a diagram illustrating a one-way clutch, according to an embodiment; 
         FIGS. 8 and 9  are diagrams illustrating a one-way clutch for driving the developing roller in one direction, according to embodiments; 
         FIG. 10  is a diagram illustrating a speed reducer between the driving gear and the driving member, according to an embodiment; 
         FIG. 11  is a diagram illustrating an example of a driving connection structure of a case in which the developing roller and the photosensitive drum are driven by a same driving motor; 
         FIG. 12  is a diagram illustrating an example of a driving connection structure of a case in which the developing roller and the photosensitive drum are driven by different driving motors; 
         FIG. 13  is a diagram illustrating the development cartridge, according to an embodiment; 
         FIGS. 14 and 15  are diagrams illustrating the development cartridge, according to an embodiment; 
         FIG. 16  is a diagram illustrating the development cartridge, according to an embodiment; and 
         FIG. 17  is a diagram illustrating the development cartridge, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to example embodiments which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the disclosure by referring to the figures. 
     The disclosure will be described in detail by explaining embodiments of an electrophotographic image forming apparatus and a development cartridge with reference to the attached drawings. Throughout the specification and drawings, those elements performing substantially the same function are rendered the same reference numeral, and redundant explanations thereof are omitted. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
       FIG. 1  is a schematic configuration diagram illustrating an electrophotographic image forming apparatus, according to an embodiment. The electrophotographic image forming apparatus (also referred to as the image forming apparatus) according to the embodiment prints a color image, according to an electrophotographic manner. 
     Referring to  FIG. 1 , the image forming apparatus may include a main body  1  and a plurality of development cartridges  10  detachably attached to the main body  1 . For example, a front surface of the main body  1  may be open by opening a door  2 , and the plurality of development cartridges  10  may be mounted to or detached from the main body  1 . Although not illustrated, the door  2  may open or close a side surface or a top surface of the main body  1 . 
     The plurality of development cartridges  10  may include development cartridges  10 C,  10 M,  10 Y, and  10 K for respectively developing toners of a cyan color (C), a magenta color (M), a yellow color (Y), and a black color (B). However, the scope of the disclosure is not limited thereto, and the image forming apparatus may further include development cartridges  10  for developing toners of other various colors such as a light magenta color, a white color, or the like. Hereinafter, the image forming apparatus including the development cartridges  10 C,  10 M,  10 Y, and  10 K will now be described, and unless there is a particular description contrary thereto, items with reference numerals C, M, Y, and K indicate elements for developing toners with a cyan color, a magenta color, a yellow color, and a black color. 
     Each of the development cartridges  10  may include a toner container  21  and a developing section  23 . A toner contained in the toner container  21  is supplied to the developing section  23  through a supply hole  22 . The toner container  21  may include a stirring member  19  for stirring the toner and supplying the toner to the developing section  23 . The developing section  23  may include a photosensitive drum  11  on which an electrostatic latent image is formed, and a developing roller  12  for developing a visible toner image by supplying a toner of the developing section  23  to the electrostatic latent image. The photosensitive drum  11 , as a photosensitive body on which an electrostatic latent image is formed, may include a conductive metal pipe and a photosensitive layer formed at its outer circumference. 
     A surface of the photosensitive drum  11  is charged by a charger so as to have a uniform surface potential. A charging roller  16  is an example of the charger. Instead of the charging roller  16 , a charging brush, a corona charger, or the like may be used. The development cartridge  10  may further include a charging roller cleaner  17  for removing foreign substances such as toners, dusts, or the like attached to the charging roller  16 . The charging roller cleaner  17  may be a roller that rotates while contacting the charging roller  16 . 
     The development cartridge  10  may further include a cleaning member  18  and a waste toner container  24 , wherein the cleaning member  18  removes residual toners on the surface of the photosensitive drum  11  after an intermediate transfer process to be described below, and the waste toner container  24  contains the toners removed from the photosensitive drum  11 . 
     The developing roller  12  supplies a toner to the surface of the photosensitive drum  11  while the developing roller  12  rotates and contacts the photosensitive drum  11 . A supply roller  13  for supplying a toner in the developing section  23  to the developing roller  12  may be arranged in the developing section  23 . A regulation member  14  regulates an amount of toner to be supplied to a development area where the photosensitive drum  11  and the developing roller  12  face each other. A development stirring member  15  for stirring a toner in the developing section  23  may be further arranged in the developing section  23 . In the embodiment, the development stirring member  15  and the stirring member  19  may have a same form. 
     The development cartridge  10  in the embodiment is integral type development cartridge in which the toner container  21 , the developing section  23 , and the waste toner container  24  are integrated as one body. 
     An exposure device  40  forms the electrostatic latent image on the photosensitive drum  11  by irradiating light to the photosensitive drum  11 , the light being modulated according to image information. Examples of the exposure device  40  may include a laser scanning unit (LSU) using a laser diode as a light source, a light emitting diode (LED) exposure device using an LED as a light source, or the like. 
     An intermediate transfer belt  30  temporarily has a toner image developed on the photosensitive drum  11  of each of the development cartridges  10 C,  10 M,  10 Y, and  10 K. A plurality of intermediate transfer rollers  50  are positioned to face the photosensitive drums  11  of the development cartridges  10 C,  10 M,  10 Y, and  10 K by interposing the intermediate transfer belt  30  therebetween. An intermediate transfer bias voltage is applied to the plurality of intermediate transfer rollers  50  so as to intermediately transfer toner images, which are developed on the photosensitive drums  11 , to the intermediate transfer belt  30 . Instead of the intermediate transfer roller  50 , a corona transfer device or a pin scorotron-type transfer device may be used. 
     A transfer roller  60  is positioned to face the intermediate transfer belt  30 . A transfer bias voltage is applied to the transfer roller  60  so as to transfer, to a recording medium P, the toner image that is transferred to the intermediate transfer belt  30 . 
     In the embodiment, it is described that the image developed on the photosensitive drums  11  is intermediately transferred to the intermediate transfer belt  30 , and then is transferred to the recording medium P that passes through a nip between the intermediate transfer belt  30  and the transfer roller  60 , but the disclosure is not limited thereto. That is, the recording medium P may directly pass through a nip between the intermediate transfer belt  30  and the photosensitive drums  11  so that the developed image may be directly transferred to the recording medium P. In this case, the transfer roller  60  is not employed. 
     A fixer  70  fixes the toner image onto the recording medium P by applying heat and/or a pressure to the toner image transferred to the recording medium P. A form of the fixer  70  is not limited to the embodiment of  FIG. 1 . 
     An image forming procedure according to the aforementioned configuration will now be briefly described. 
     The charging roller  16  charges the photosensitive drums  11  of the development cartridges  10 C,  10 M,  10 Y, and  10 K to have a uniform surface potential. 
     The exposure device  40  forms electrostatic latent images on the photosensitive drums  11  by scanning lights to the photosensitive drums  11  of the development cartridges  10 C,  10 M,  10 Y, and  10 K, the lights being modulated according to a plurality of pieces of image information of colors. The electrostatic latent images of the photosensitive drums  11  of the development cartridges  10 C,  10 M,  10 Y, and  10 K are developed to visible toner images due to C, M, Y, and K toners in the development cartridges  10 C,  10 M,  10 Y, and  10 K. The developed toner images are intermediately transferred in a sequential order to the intermediate transfer belt  30 . The recording medium P loaded in a feeding member  80  is delivered to a nip between the transfer roller  60  and the intermediate transfer belt  30 . The toner images that are intermediately transferred onto the intermediate transfer belt  30  are transferred to the recording medium P due to a transfer bias applied to the transfer roller  60 . When the recording medium P passes through the fixer  70 , the toner images are fixed onto the recording medium P due to heat and a pressure. The recording medium P for which fixing is completed is discharged by a discharging roller  90 . 
       FIGS. 2 and 3  illustrate side views of the development cartridge  10 , according to an embodiment.  FIG. 2  illustrates a state of the development cartridge  10  in which the photosensitive drum  11  and the developing roller  12  are located at a development position, and  FIG. 3  illustrates a state of the development cartridge  10  in which the photosensitive drum  11  and the developing roller  12  are located at a non-development position. 
     Referring to  FIGS. 2 and 3 , the development cartridge  10  may include a photosensitive unit  100  and a developing unit  200 . The photosensitive unit  100  may include a first frame  101  and the photosensitive drum  11  supported by the first frame  101 . The developing unit  200  may include a second frame  201  and the developing roller  12  supported by the second frame  201 . The photosensitive unit  100  and the developing unit  200  are connected to each other so as to rotate to the development position (refer to  FIG. 2 ) where the photosensitive drum  11  and the developing roller  12  contact each other to form a development nip N 1  and the non-development position (refer to  FIG. 3 ) where the photosensitive drum  11  and the developing roller  12  are spaced apart from each other to release the development nip N 1 . For example, the photosensitive unit  100  and the developing unit  200  are connected to rotate around a hinge axis  301 . In the image forming apparatus, the photosensitive drum  11  is related to a location of the intermediate transfer roller  50 , or the like, thus, when the development cartridge  10  is mounted to the main body  1 , a location of the photosensitive drum  11  is fixed. The developing unit  200  is coupled to the photosensitive unit  100  so as to be rotatable with respect to the hinge axis  301 . However, the disclosure is not limited thereto, and thus the developing unit  200  may be located at a fixed position in the main body  1 , and the photosensitive unit  100  may be coupled to the developing unit  200  so as to be rotatable with respect to the hinge axis  301 . 
     An elastic member  330  provides an elastic force to the developing unit  200  to rotate in a direction where the development nip N 1  is to be formed. Due to the elastic force of the elastic member  330 , the developing unit  200  rotates with respect to the hinge axis  301 , so that the developing roller  12  contacts the photosensitive drum  11  and thus the development nip N 1  is formed as shown in  FIG. 2 .  FIGS. 2 and 3  illustrate, as an example of the elastic member  330 , a tension coil spring of which ends are supported by the developing unit  200  and the photosensitive unit  100 , respectively, but the example of the elastic member  330  is not limited thereto. For example, a member having one of various types including a torsion coil spring, a plate spring, or the like may be used as the elastic member  330 . 
     Rotational members of the development cartridge  10 , e.g., the photosensitive drum  11 , the charging roller  16 , the developing roller  12 , the supply roller  13 , the development stirring member  15 , or the like, may be driven by being connected to a driving motor (not shown) arranged at the main body  1  when the development cartridge  10  is mounted in the main body  1 . For example, the development cartridge  10  may have a coupler  310  to be connected to the driving motor (not shown) arranged at the main body  1  when the development cartridge  10  is mounted in the main body  1 . The rotational members may be connected to the coupler  310  by a power connecting unit (not shown), e.g., gears. The development cartridge  10  may further have a coupler  320  to be connected to the driving motor (not shown) arranged at the main body  1  when the development cartridge  10  is mounted in the main body  1 . In this case, the rotational members (second rotational members) of the developing unit  200 , e.g., the developing roller  12 , the supply roller  13 , the development stirring member  15 , or the like, may be driven by being connected to the coupler  310 , and the rotational members (first rotational members) of the photosensitive unit  100 , e.g., the photosensitive drum  11 , the charging roller  16 , or the like, may be driven by being connected to the coupler  320 . For example, the coupler  320  may be positioned on a same axis as a rotation axis of the photosensitive drum  11  or may be positioned on the rotation axis of the photosensitive drum  11 . Although not illustrated, the coupler  310  may be skipped (omitted), and the coupler  320  may be connected with the developing roller  12 , the supply roller  13 , and the development stirring member  15 . 
     In the embodiment, the rotational members of the developing unit  200  are driven by the coupler  310 , and the rotational members of the photosensitive unit  100  are driven by the coupler  320 .  FIG. 4  illustrates an example of a driving connection structure of the rotational members of the developing unit  200  and the photosensitive unit  100 . Referring to  FIG. 4 , the coupler  310  may include a gear  311 . Gears  210 ,  220 , and  230  are respectively connected to rotation axes  12   a ,  13   a , and  15   a  of the developing roller  12 , the supply roller  13 , and the development stirring member  15 . The gear  210  is a double stage gear including a gear unit  210   a  and a gear unit  210   b . The gear unit  210   a  meshes with the gear  311 , and the gear unit  210   b  meshes with the gear  220 . Torque that is delivered from the main body  1  to the coupler  310  may be delivered to the developing roller  12 , the supply roller  13 , and the development stirring member  15  through a gear train of the gear  311 -the gear  210 -the gear  220 -the gear  230 . The coupler  320  is coupled to a rotation axis  11   a  of the photosensitive drum  11 . A gear  110  and a gear  120  are respectively coupled to the rotation axis  11   a  of the photosensitive drum  11  and a rotation axis  16   a  of the charging roller  16 . The gear  110  and the gear  120  mesh with each other. By doing so, torque that is delivered from the main body  1  to the coupler  320  may be delivered to the photosensitive drum  11  and the charging roller  16 . 
     The hinge axis  301  may be coaxial with the rotation axis of the coupler  310 , but a location of the hinge axis  301  is not limited thereto. The hinge axis  301  may be arranged at a location appropriate for the photosensitive unit  100  and the developing unit  200  to form or not form the development nip N 1 . 
     In order to perform a printing operation, the developing roller  12  and the photosensitive drum  11  contact each other and thus are located at a development position for forming the development nip N 1 , and when the developing roller  12  and the photosensitive drum  11  do not perform the printing operation, the developing roller  12  and the photosensitive drum  11  are spaced apart from each other and thus are located at a non-development position where the development nip N 1  is released. In order to form or release the development nip N 1 , referring to  FIGS. 2 and 3 , the development cartridge  10  may include a first moving member  500 . 
     In the embodiment, according to a rotation direction of a driving gear to rotate at least one of rotational members of the development cartridge  10 , the first moving member  500  is shifted to a first location (refer to  FIG. 2 ) where the developing roller  12  and the photosensitive drum  11  are located at the development position, and is shifted to a second location (refer to  FIG. 3 ) where the developing roller  12  and the photosensitive drum  11  are located at the non-development position. For example, when the driving gear rotates in a first direction A 1  for a printing operation, the first moving member  500  is shifted from the second location to the first location, and when the driving gear rotates in a second direction A 2  that is opposite to the first direction A 1 , the first moving member  500  is shifted from the first location to the second location. 
     Hereinafter, with respect to rotation directions of gears, rotational members, and all rotational elements, a rotation direction during a printing operation is marked as the first direction A 1 , and a rotation direction during a non-printing operation is marked as the second direction A 2 . 
     When the first moving member  500  is shifted from the first location to the second location, the developing unit  200  rotates with respect to the hinge axis  301  in a direction opposite to the elastic force of the elastic member  330 , so that the developing roller  12  and the photosensitive drum  11  are shifted from the development position to the non-development position. When the first moving member  500  is shifted from the second location to the first location, the developing unit  200  rotates with respect to the hinge axis  301  due to the elastic force of the elastic member  330 , so that the developing roller  12  and the photosensitive drum  11  are shifted from the non-development position to the development position. When the first moving member  500  is shifted from the second location to the first location, the first moving member  500  allows the developing unit  200  to rotate in a direction to the development position. 
     Hereinafter, embodiments of a structure for shifting the first moving member  500  between the first location and the second location will now be described. 
       FIG. 5  is a schematic configuration diagram illustrating a structure in which the first moving member  500  is shifted to the first location or the second location, according to an embodiment. In the embodiment, the first moving member  500  may slide to the first location or the second location according to a rotation direction of the driving gear  210  that drives the developing roller  12 . Referring to  FIG. 5 , the first moving member  500  is mounted on the second frame  201  so as to slide in a reciprocating direction. The driving gear  210  is arranged on the rotation axis  12   a  of the developing roller  12 . The driving gear  210  is coupled to the rotation axis  12   a  of the developing roller  12  so as to rotate together with the developing roller  12 . A driving member  510  is coupled to the rotation axis  12   a  of the developing roller  12  so as to shift the first moving member  500  to the first location or the second location. The driving member  510  is coaxially arranged with respect to the driving gear  210  and thus is rotated by the driving gear  210 . Rack gear parts  501  are arranged at the first moving member  500 , and pinion gear parts  511  to be engaged with the rack gear parts  501  are arranged at the driving member  510 . Therefore, when the driving member  510  rotates, the first moving member  500  is linearly shifted. 
     The driving member  510  is selectively connected with the driving gear  210  according to a rotation direction of the driving gear  210 . For example, when the driving gear  210  rotates in the first direction A 1 , the driving member  510  is disconnected from the driving gear  210  and thus does not rotate. When the driving gear  210  rotates in the second direction A 2 , the driving member  510  is connected with the driving gear  210  and thus rotates. 
       FIG. 6  is a diagram illustrating a one-way clutch (a first one-way clutch) that selectively connects the driving member  510  with the driving gear  210 , according to an embodiment. Referring to  FIG. 6 , the one-way clutch may include a first clutch unit  211  and a second clutch unit  512 , wherein the first clutch unit  211  is arranged at the driving gear  210  and the second clutch unit  512  is arranged at the driving member  510 . The first clutch unit  211  has a structure in which a first stumbling portion  211   a  and a first slope portion  211   b  are alternately arrayed in a circumferential direction. The second clutch unit  512  has a structure in which a second stumbling portion  512   a  and a second slope portion  512   b  are alternately arrayed in the circumferential direction, wherein the second stumbling portion  512   a  and the second slope portion  512   b  face the first stumbling portion  211   a  and the first slope portion  211   b , respectively. An elastic member  520  pushes the driving member  510  toward the driving gear  210 . 
     According to the aforementioned configuration, when the driving gear  210  rotates in the first direction A 1 , the first and second slope portions  211   b  and  512   b  contact each other, so that the driving member  510  is pushed in an opposite direction of an elastic force of the elastic member  520  as shown using a broken line in  FIG. 6 . Therefore, the first and second stumbling portions  211   a  and  512   a  are spaced apart from each other, and thus, even though the driving gear  210  rotates, the driving member  510  does not rotate. When the driving gear  210  rotates in the second direction A 2 , the driving member  510  is pushed toward the driving gear  210  due to the elastic force of the elastic member  520 , and when the first and second stumbling portions  211   a  and  512   a  face each other and the driving gear  210  rotates in the second direction A 2 , the driving member  510  also rotates in the second direction A 2 . 
     Referring to  FIGS. 2 and 5 , the first moving member  500  is located at the first location. The photosensitive drum  11  and the developing roller  12  are located at the development position while contacting each other due to the elastic force of the elastic member  330 . In this state, when the driving gear  210  rotates in the first direction A 1 , as shown using the broken line in  FIG. 6 , the first and second clutch units  211  and  512  are spaced apart from each other so that the driving gear  210  is disconnected from the driving member  510 , thus, the driving member  510  does not rotate. Therefore, while a printing operation is performed, the photosensitive drum  11  and the developing roller  12  remain at the development position. 
     When the printing operation is ended, for example, the driving motor arranged at the main body  1  rotates the driving gear  210  in the second direction A 2 . Then, as shown using a solid line in  FIG. 6 , the first and second clutch units  211  and  512  are connected with each other, the driving member  510  rotates in the second direction A 2 . Due to the pinion gear parts  511  and the rack gear parts  501 , the first moving member  500  moves forward toward the photosensitive drum  11 . The first moving member  500  pushes the photosensitive unit  100 . For example, the first moving member  500  may contact a contact portion  104  of the first frame  101  supporting the photosensitive drum  11  and may push the photosensitive unit  100 . When the photosensitive drum  11  is mounted in the main body  1 , the photosensitive drum  11  is fixed in the main body  1 , thus, the photosensitive unit  100  is also fixed in the main body  1 . Therefore, the developing unit  200  rotates with respect to the hinge axis  301  in an opposite direction of the elastic force of the elastic member  330 , i.e., the developing unit  200  rotates in a direction B 1  of  FIG. 5 . As shown in  FIG. 3 , when the first moving member  500  arrives at the second location, the developing roller  12  arrives at the non-development position spaced apart from the photosensitive drum  11 . Since the rack gear parts  501 , the pinion gear parts  511 , the first clutch unit  211 , and the second clutch unit  512  are engaged with each other, and the driving gear  210  is connected with the driving motor of the main body  1 , in spite of the elastic force of the elastic member  330 , when the driving gear  210  is stopped, the photosensitive drum  11  and the developing roller  12  remain at the non-development position. 
     When the driving gear  210  rotates in the first direction A 1  so as to perform a printing operation in a state shown in  FIG. 3 , as shown using the broken line in  FIG. 6 , the second clutch unit  512  is spaced apart from the first clutch unit  211  so that the driving gear  210  is disconnected from the driving member  510 , and the driving member  510  may freely rotate. Due to the elastic force of the elastic member  330 , the second frame  201  rotates with respect to the hinge axis  301  in a direction where the developing roller  12  approaches the photosensitive drum  11 , i.e., a direction B 2  of  FIG. 5 . When the second frame  201  rotates in the direction B 2 , the first moving member  500  is shifted from the first location to the second location, and the driving member  510  naturally rotates in the first direction A 1  so that the driving member  510  allows the first moving member  500  to be shifted from the first location to the second location. The developing roller  12  and the photosensitive drum  11  arrive at the development position where the developing roller  12  and the photosensitive drum  11  contact each other, and the first moving member  500  arrives at the second location. 
     According to the aforementioned configuration, a driving structure for driving the first moving member  500  is arranged in the development cartridge  10 , and it is not required to arrange a separate device in the main body  1 . Therefore, it is possible to drive the first moving member  500  by using the driving motor that drives the rotational members of the development cartridge  10  by using the simple driving structure. 
     In a case in which an integrated first moving member (not shown) for integrally controlling the development nips N 1  of the development cartridges  10 C,  10 M,  10 Y, and  10 K is arranged at the main body  1 , elastic forces of the elastic member  330  of the development cartridges  10 C,  10 M,  10 Y, and  10 K are simultaneously applied to the integrated first moving member, thus, a motor having a large driving force is required to drive the integrated first moving member and durability of each of the integrated first moving member and a driving member for driving the integrated first moving member may deteriorate. According to the embodiment, since the first moving member  500  is arranged at each of the development cartridges  10 C,  10 M,  10 Y, and  10 K, the development nips N 1  of the development cartridges  10 C,  10 M,  10 Y, and  10 K may be individually controlled. Therefore, it is possible to drive the first moving member  500  by using a small driving force, and durability of a driving member for controlling the development nips N 1  may be relatively improved. In addition, in order to print a single-colored image, the photosensitive drum  11  and the developing roller  12  of each of the development cartridges  10 C,  10 M, and  10 Y are located at the non-development position, and the photosensitive drum  11  and the developing roller  12  of the development cartridge  10 K may be located at the development position. 
     In addition, the first moving member  500  is driven by the small driving force, and a speed of the driving motor while the driving motor drives the first moving member  500  may be adjusted. Therefore, a shift speed for shifting the photosensitive drum  11  and the developing roller  12  from the development position to the non-development position may be adjusted by adjusting the speed of the driving motor, so that noise due to a position change may be decreased. 
     A distance between the photosensitive drum  11  and the developing roller  12  at the non-development position may be controlled by controlling an amount of rotation of the driving gear  210  in the second direction A 2 . In other words, the amount of rotation of the driving gear  210  in the second direction A 2  may be controlled by controlling an amount of rotation of the driving motor (not shown) arranged at the main body  1 . A size of the development nip N 1 , i.e., an amount of overlap between the developing roller  12  and the photosensitive drum  11  at the development position may be quite different from a designed value, according to a manufacture error of the elements that configure the development cartridge  10 . Even if a desired separation distance cannot be achieved at the non-development position due to the manufacture error, the desired separation distance may be achieved by adjusting the amount of rotation of the driving motor, without modifying shapes of elements for controlling a development nip, for example, shapes of the first moving member  500 , the second frame  201  at which the first moving member  500  is mounted, or the like. Therefore, according to the embodiment, an error of the separation distance due to the manufacture error may be compensated for by software-based modification that involves adjusting the amount of rotation of the driving motor. 
     The separation distance between the photosensitive drum  11  and the developing roller  12  is controlled by the first moving member  500  only at the non-development position. At the development position, the first moving member  500  does not greatly affect the size of the development nip N 1 . Therefore, the development nip N 1  may be stably maintained resulting in stability of an image quality. 
     The one-way clutch is not limited to the example of  FIG. 6 .  FIG. 7  is a diagram illustrating a one-way clutch (a first one-way clutch), according to an embodiment.  FIG. 7  illustrates the one-direction clutch with a spring clutch structure. Referring to  FIG. 7 , the driving member  510  is rotatably arranged on the rotation axis  12   a  of the developing roller  12 . A clutch spring  530  is wound up around the rotation axis  12   a  of the developing roller  12 . An end  531  of the clutch spring  530  projects in a radial direction and is held in a spring groove  513  of the driving member  510 . When the driving gear  210  not shown in the embodiment is coupled to the rotation axis  12   a  of the developing roller  12  and then rotates, the developing roller  12  rotates. 
     When the developing roller  12  rotates in the first direction A 1 , the end  531  of the clutch spring  530  pushes an end  513   a  of the groove  513 . Here, a reaction force in the second direction A 2  is applied to the end  531 , due to that, the clutch spring  530  is slightly loosened from the rotation axis  12   a . Then, the rotation axis  12   a  slips with respect to the clutch spring  530 , and torque of the rotation axis  12   a  is not delivered to the clutch spring  530 . Therefore, the driving member  510  does not rotate. 
     When the developing roller  12  rotates in the second direction A 2 , the end  531  of the clutch spring  530  pushes an end  513   b  of the groove  513 . Here, a reaction force in the first direction A 1  is applied to the end  531 , due to that, the clutch spring  530  tightens the rotation axis  12   a . By doing so, the clutch spring  530  rotates together with the rotation axis  12   a , and since the end  531  pushes the driving member  510 , the driving member  510  also rotates in the second direction A 2 . 
     According to the aforementioned configuration, it is possible to selectively rotate the driving member  510  according to a rotation direction of the driving gear  210 . 
     The developing roller  12  may rotate only when the driving gear  210  rotates in the first direction A 1 , and may not rotate when the driving gear  210  rotates in the second direction A 2 . To do so, the one-way clutch may also be arranged between the driving gear  210  and the developing roller  12 . 
       FIGS. 8 and 9  are diagrams illustrating a one-way clutch for driving the developing roller  12  in one direction, according to one or more embodiments. Referring to  FIGS. 8 and 9 , a driving bush  540  is coupled to the rotation axis  12   a  of the developing roller  12 . The driving gear  210  and the driving member  510  are rotatably coupled to the rotation axis  12   a . A first one-way clutch is arranged between the driving gear  210  and the driving member  510 , and a second one-way clutch is arranged between the driving gear  210  and the driving bush  540 . 
     A structure of the first one-way clutch is equal to a structure of the one-way clutch shown in  FIG. 6 . That is, the driving gear  210  and the driving member  510  are selectively connected by the first and second clutch units  211  and  512  according to a rotation direction of the driving gear  210 . That is, when the driving gear  210  rotates in the first direction A 1 , the first one-way clutch disconnects power between the driving gear  210  and the driving member  510 , and when the driving gear  210  rotates in the second direction A 2 , the first one-way clutch connects the power between the driving gear  210  and the driving member  510 . 
     The second one-way clutch may be embodied by a third clutch unit  212  and a fourth clutch unit  541 , wherein the third clutch unit  212  is arranged at the driving gear  210  and the fourth clutch unit  541  is arranged at the driving bush  540 . Structures of the third and fourth clutch units  212  and  541  are the same as structures of the first and second clutch units  211  and  512 . However, the third and fourth clutch units  212  and  541  are connected to each other when the driving gear  210  rotates in the first direction A 1 , so that the driving gear  210  and the driving bush  540  rotate together, and when the driving gear  210  rotates in the second direction A 2 , the third and fourth clutch units  212  and  541  are spaced apart from each other, so that the driving bush  540  does not rotate. 
     When the driving gear  210  rotates in the first direction A 1  for a printing operation, as shown in  FIG. 8 , the third and fourth clutch units  212  and  541  are engaged with each other so that the driving bush  540  and the driving gear  210  rotate together in the first direction A 1 . Therefore, the developing roller  12  rotates in the first direction A 1 . In this regard, since the first clutch unit  211  and the second clutch unit  512  are spaced apart from each other, the driving member  510  does not rotate. 
     After the printing operation is ended, when the driving gear  210  rotates in the second direction A 2 , the third clutch unit  212  moves away from the fourth clutch unit  541 , and the driving gear  210  is spaced apart from the driving bush  540  and is moved toward the driving member  510  along the rotation axis  12   a . The connection between the third and fourth clutch units  212  and  541  is disconnected, the first and second clutch units  211  and  512  are connected with each other. Thus, when the driving gear  210  rotates in the second direction A 2 , the driving bush  540  and the developing roller  12  do not rotate, and the driving member  510  rotates in the second direction A 2 , so that the first moving member  500  may be shifted from the first location to the second location. 
     When the driving gear  210  rotates in the first direction A 1  in a state shown in  FIG. 9 , the first clutch unit  211  is spaced apart from the second clutch unit  512 , and the driving gear  210  is spaced apart from the driving member  510  and approaches toward the driving bush  540 . The third clutch unit  212  and the fourth clutch unit  541  are connected with each other, and the connection between the first and second clutch units  211  and  512  is disconnected. Therefore, when the driving gear  210  keeps rotating in the first direction A 1 , the driving bush  540  and the developing roller  12  rotate in the first direction A 1 . The developing unit  200  rotates with respect to the hinge axis  301  so as to locate the photosensitive drum  11  and the developing roller  12  at the development position by using the elastic force of the elastic member  330 . Since the developing unit  200  rotates, the first moving member  500  is shifted from the second location to the first location, and the driving member  510  slightly rotates in the first direction A 1 . 
     A speed reducer may be arranged between the driving gear  210  and the driving member  510 . By doing so, it is possible to stably control the development nip N 1  without increasing torque of the driving motor. In addition, it is possible to precisely control a position of the first moving member  500 . 
       FIG. 10  is a diagram illustrating the speed reducer between the driving gear  210  and the driving member  510 , according to an embodiment. Referring to  FIG. 10 , the driving gear  210  may include a sun gear  210   c . For example, three planet gears  510   a ,  510   b , and  510   c  are rotatably mounted at the driving member  510 . The three planet gears  510   a ,  510   b , and  510   c  are engaged with the sun gear  210   c . According to the aforementioned configuration, when the driving gear  210  rotates, the driving member  510  decelerates and rotates in an opposite direction. Therefore, although not illustrated, the rack gear parts  501  of the first moving member  500  are arranged to be engaged with the pinion gear parts  511  above the driving member  510  in  FIG. 5 . 
     With this configuration, it is possible to embody the speed reducer that occupies a very compact space. 
     When the driving gear  210  rotates in the second direction A 2 , the driving member  510  rotates in the first direction A 1 , and a first moving member  500  is shifted from the first location to the second location. When the driving gear  210  rotates in the first direction A 1 , the driving member  510  rotates in the second direction A 2 , and the first moving member  500  is shifted from the second location to the first location. In this state, connection between the rack gear parts  501  and the pinion gear parts  511  is disconnected, and the first moving member (nip control member)  500  remains at the first location. 
     The one-way clutch shown in  FIG. 7  may be arranged between the driving gear  210  and the sun gear  210   c . Referring to  FIG. 10 , a bush  210   d  is arranged at the driving gear  210 , and the clutch spring  530  is wound up around the bush  210   d . The sun gear  210   c  is inserted into the driving gear  210  while the sun gear  210   c  surrounds the clutch spring  530 . 
     A connection relationship between the clutch spring  530  and the bush  210   d  is understandable by treating the driving member  510  of  FIG. 7  as the sun gear  210   c  and treating the rotation axis  12   a  as the bush  210   d . According to the aforementioned configuration, when the driving gear  210  rotates in the first direction A 1 , the sun gear  210   c  does not rotate, and the driving member  510  does not rotate either. Only when the driving gear  210  rotates in the second direction A 2 , the sun gear  210   c  may rotate in the second direction A 2 , and the driving member  510  may rotate in the first direction A 1 . 
     In the aforementioned embodiments, the developing roller  12  and the photosensitive drum  11  may be driven by a same driving motor.  FIG. 11  is a diagram illustrating an example of a driving connection structure of a case in which the developing roller  12  and the photosensitive drum  11  are driven by a same driving motor  3 . Referring to  FIG. 11 , the driving motor  3  may drive the developing roller  12  through the coupler  310  and the driving gear  210 . In addition, the driving motor  3  may drive the photosensitive drum  11  through the coupler  320 . The driving member  510  may be connected with the driving gear  210  by having a one-way clutch  4   a  arranged therebetween, or may be connected with the driving gear  210  through a one-way clutch  4   b  and the developing roller  12 . The one-way clutch  4   a  may be the one-way clutch shown in  FIG. 6 , and the one-way clutch  4   b  may be the one-direction clutch shown in  FIG. 7 . According to the aforementioned configuration, when the driving gear  210  rotates in the first direction A 1  or the second direction A 2 , the developing roller  12  and the photosensitive drum  11  also rotate. 
     The developing roller  12  may be connected with the driving gear  210  through a one-way clutch  4   c . In this case, the driving member  510  is connected with the driving gear  210  through the one-way clutch  4   a . The one-way clutch  4   a  and the one-way clutch  4   c  may each be the one-way clutch shown in  FIG. 8 . According to the aforementioned configuration, when the driving gear  210  rotates in the first direction A 1  or the second direction A 2 , the photosensitive drum  11  rotates in both cases but the developing roller  12  rotates only when the driving gear  210  rotates in the first direction A 1 . 
     The photosensitive drum  11  may rotate only when the driving gear  210  rotates in the first direction A 1 , and may not rotate when the driving gear  210  rotates in the second direction A 2 . In this case, for example, a one-way clutch  4   e  may be arranged between the coupler  320  and the photosensitive drum  11 . It is apparent that a one-way clutch  4   d  may be arranged between the driving motor  3  and the coupler  320 . The one-way clutches  4   e  and  4   d  may each be the one-way clutch shown in  FIG. 6 or 7 . 
       FIG. 12  is a diagram illustrating an example of a driving connection structure of a case in which the developing roller  12  and the photosensitive drum  11  are driven by different driving motors. Referring to  FIG. 12 , a first driving motor  3   a  drives the photosensitive drum  11  through the coupler  320 . A second driving motor  3   b  may drive the developing roller  12  through the coupler  310  and the driving gear  210 . The driving member  510  may be connected with the driving gear  210  by having the one-way clutch  4   a  arranged therebetween, or may be connected with the driving gear  210  through the one-way clutch  4   b  and the developing roller  12 . The one-way clutch  4   a  may be the one-way clutch shown in  FIG. 6 , and the one-way clutch  4   b  may be the one-way clutch shown in  FIG. 7 . According to the aforementioned configuration, when the driving gear  210  rotates in the first direction A 1  or the second direction A 2 , the developing roller  12  also rotates. The developing roller  12  may be connected with the driving gear  210  through the one-way clutch  4   c . In this case, the driving member  510  is connected with the driving gear  210  through the one-way clutch  4   a . The one-way clutch  4   a  and the one-way clutch  4   c  may each be the one-way clutch shown in  FIG. 8 . According to the aforementioned configuration, the developing roller  12  rotates only when the driving gear  210  rotates in the first direction A 1 . 
     The photosensitive drum  11  may turn on or off the first driving motor  3   a  according to a rotation direction of the driving gear  210 , so that the photosensitive drum  11  may rotate when the driving gear  210  rotates in the first direction A 1 , and may stop when the driving gear  210  rotates in the second direction A 2 . 
     In the aforementioned embodiment, it is described that the first moving member  500  is driven by using the driving gear  210  coupled to the rotation axis  12   a  of the developing roller  12 , but the scope of the disclosure is not limited thereto. The first moving member  500  may be driven by using another rotational member such as the gear  220  coupled to the rotation axis  13   a  of the supply roller  13 , or the gear  230  coupled to the rotation axis  15   a  of the development stirring member  15 . In this case, the driving member  510  may be arranged on the rotation axis  13   a  of the supply roller  13  or the rotation axis  15   a  of the development stirring member  15 , and in the aforementioned embodiments, the driving gear  210  may be the gear  220  or the gear  230 . 
     In addition, it is not required that a driving gear that selectively drives the driving member  510  is necessarily arranged at the rotational member of the development cartridge  10 , for example, one of the rotation axes  12   a ,  13   a , and  15   a  of the developing roller  12 , the supply roller  13 , and the development stirring member  15 . It is acceptable that the driving gear is one of gears that belong to the gear train for driving the rotational member of the developing unit  200 . 
       FIG. 13  is a diagram illustrating the development cartridge  10 , according to an embodiment. Referring to  FIG. 13 , an axis  202  is mounted at the second frame  201  of the developing unit  200 . A driving gear  250  and the driving member  510  are coupled to the axis  202 . The driving gear  250  receives torque from the coupler  310 . For example, the driving gear  250  is engaged with the gear unit  210   b  of the driving gear  210 . 
     A structure of the driving gear  250  and the driving member  510  is the same as in the aforementioned embodiment. For example, the axis  202  may be fixed at the second frame  201 , and the driving gear  250  is mounted to be rotatable with respect to the axis  202 . The driving gear  250  and the driving member  510  may have same forms as those of the driving gear  210  and the driving member  510  shown in  FIG. 6 . In this case, the driving gear  210  of  FIG. 6  may be the driving gear  250 . 
     When the axis  202  is coupled to the second frame  201  so as to rotate together with the driving gear  250 , the driving member  510  may be selectively power-connected to the axis  202  by the clutch spring  530 , as shown in  FIG. 7 . In this case, in  FIG. 7 , the rotation axis  12   a  may be the axis  202 . 
     According to the aforementioned configuration, when the driving gear  250  rotates in the first direction A 1  for a printing operation, the driving member  510  does not rotate. Therefore, the first moving member  500  is located at the first location, and the photosensitive drum  11  and the developing roller  12  are located at the development position as shown in  FIG. 2 . 
     When the driving gear  250  rotates in the second direction A 2 , the driving member  510  is connected with the driving gear  250  and thus rotates in the second direction A 2 . Then, the first moving member  500  is shifted from the first location to the second location, and the second frame  201  rotates with respect to the hinge axis  301  in a direction opposite to the elastic force of the elastic member  330 , so that the photosensitive drum  11  and the developing roller  12  are located at the non-development position where the photosensitive drum  11  and the developing roller  12  are spaced apart from each other. In this state, when the developing roller  12  rotates in the first direction A 1  and thus the driving gear  210  rotates in the second direction A 2 , connection between the driving gear  250  and the driving member  510  is disconnected, and the driving member  510  may freely rotate. Due to the elastic force of the elastic member  330 , the second frame  201  rotates with respect to the hinge axis  301  in a direction where the photosensitive drum  11  and the developing roller  12  contact each other, and the first moving member  500  slightly rotates the driving member  510  in the second direction A 2  and is shifted from the second location to the first location. 
     During the printing operation, the photosensitive drum  11  and the charging roller  16  contact each other and form a charging nip N 2 . When the charging nip N 2  is formed during a non-printing operation, the photosensitive drum  11  and the charging roller  16  may be deformed and damaged. When the first moving member  500  is moved to the second location and thus the photosensitive drum  11  and the developing roller  12  are located at the non-development position, the charging roller  16  may be spaced apart from the photosensitive drum  11 , and by doing so, the development nip N 1  and the charging nip N 2  may be simultaneously controlled. 
       FIGS. 14 and 15  are diagrams illustrating the development cartridge  10 , according to an embodiment. Referring to  FIGS. 14 and 15 , the charging roller  16  is biased in a direction so as to contact the photosensitive drum  11  due to an elastic force of a second elastic member  130 . A second moving member  550  including a first lever portion  551  and a second lever portion  552  is arranged at the first frame  101 . The first lever portion  551  is located close to the rotation axis  16   a  of the charging roller  16 . The second moving member  550  may be shifted between a non-charging position and a charging position, wherein, at the non-charging position, the first lever portion  551  pushes the rotation axis  16   a  of the charging roller  16  so that the charging roller  16  is spaced apart from the photosensitive drum  11  and thus the charging nip N 2  is released, and at the charging position, the charging roller  16  contacts the photosensitive drum  11  so that the charging nip N 2  is formed. For example, the second moving member  550  may be mounted at the first frame  101  so as to be rotatable between the non-charging position and the charging position. 
     The second moving member  550  may be located at the charging position when the photosensitive drum  11  and the developing roller  12  are located at the development position, and may be shifted to the non-charging position when the photosensitive drum  11  and the developing roller  12  are located at the non-development position. The second moving member  550  may be shifted between the charging position and the non-charging position by the driving member  510 . 
     In the embodiment, an extending part  203  that extends to an inner side of the first frame  101  may be arranged at the second frame  201 . The second lever portion  552  contacts the extending part  203 . Due to an elastic force of a third elastic member  560 , the second lever portion  552  may remain contacting the extending part  203 . The third elastic member  560  applies, to the second moving member  550 , the elastic force in a direction to the charging position. 
     The second lever portion  552  may be located while being slightly spaced apart from the extending part  203 . In this case, a stopper (not shown) for allowing the second moving member  550  to remain at the charging position may be arranged at the first frame  101 . 
     As illustrated in  FIG. 14 , when the photosensitive drum  11  and the developing roller  12  are located at the development position, the first moving member  500  is located at the first location. The second moving member  550  is located at the charging position, and the charging roller  16  remains contacting the photosensitive drum  11 . 
     When the first moving member  500  is shifted from the first location to the second location by the driving member  510 , the second frame  201  rotates in a direction B 1  with respect to the hinge axis  301 . Then, the extending part  203  pushes the second lever portion  552 , and the second moving member  550  rotates to the non-charging position. The first lever portion  551  pushes the rotation axis  16   a  of the charging roller  16  so as to allow the charging roller  16  to be spaced apart from the photosensitive drum  11 . 
     When the first moving member  500  arrives at the second location, as illustrated in  FIG. 15 , the second moving member  550  arrives at the non-charging position, and the charging roller  16  is spaced apart from the photosensitive drum  11 . 
     In the state shown in  FIG. 15 , when the first moving member  500  returns to the first location, the second frame  201  rotates in a direction B 2  with respect to the hinge axis  301 , and the second moving member  550  is shifted to the charging position due to the elastic force of the third elastic member  560 . The charging roller  16  is moved to the photosensitive drum  11  due to the elastic force of the second elastic member  130  and contacts the photosensitive drum  11 . 
     According to the aforementioned configuration, the development nip N 1  and the charging nip N 2  may be simultaneously controlled by using the driving member  510 . 
     In the aforementioned embodiment, the first moving member  500  is mounted at the second frame  201 , but the first moving member  500  may be mounted at the first frame  101 .  FIG. 16  is a diagram illustrating the development cartridge  10 , according to an embodiment. Referring to  FIG. 16 , the first moving member  500  is mounted at the first frame  101  so as to be switched between the first location and the second location. The second frame  201  may include a contact part  204  that the first moving member  500  contacts when the first moving member  500  is shifted from the first location to the second location. 
     The driving member  510  is mounted on the rotation axis  11   a  of the photosensitive drum  11 . The gear  110  is arranged at the coupler  320 . The gear  110  functions as the driving gear  210  in the aforementioned embodiment. Therefore, hereinafter, the gear  110  is referred to as the driving gear  110 . The driving gear  110  may be integrated with the coupler  320 , or may be mounted on the rotation axis  11   a , separately from the coupler  320 . 
     For example the driving gear  110  may rotate together with the rotation axis  11   a . In this case, selective power connection between the driving member  510  and the driving gear  110  may be realized by the one-way clutch structure shown in  FIG. 6 . In this case, the driving gear  210  in  FIG. 6  may be the driving gear  110 . In addition, the selective power connection between the driving member  510  and the driving gear  110  may be realized by the one-way clutch structure shown in  FIG. 7 . 
     In this case, the rotation axis  12   a  in  FIG. 7  may be the rotation axis  11   a . In addition, when the speed reducer is used, the driving gear  210  in  FIG. 10  may be the driving gear  110 . Also, the driving gear  110  may be connected to the driving member  510  by a planetary reducer. In this case, as shown in  FIG. 7 , the bush  210   d  may be arranged at the driving gear  110 , and the sun gear  210   c  may be inserted into the bush  210   d  by having the clutch spring  530  arranged therebetween. 
     According to the aforementioned configuration, when the driving gear  110  rotates in the first direction A 1  for a printing operation, the driving member  510  does not rotate, the first moving member  500  remains at the first location, and the photosensitive drum  11  and the developing roller  12  are located at the development position where the photosensitive drum  11  and the developing roller  12  contact each other. 
     When the driving gear  110  rotates in the second direction A 2 , the driving member  510  rotates together with the driving gear  110 , and the first moving member  500  is switched from the first location to the second location. In this regard, the first moving member  500  pushes a part of the second frame  201 , for example, the contact part  204 , so as to rotate the second frame  201  in a direction B 1  with respect to the hinge axis  301 , that is, in a direction opposite to the elastic force of the elastic member  330 . By doing so, the developing roller  12  becomes spaced apart from the photosensitive drum  11 . When the first moving member  500  arrives at the second location, the photosensitive drum  11  and the developing roller  12  are located at the non-development position where the photosensitive drum  11  and the developing roller  12  are spaced apart from each other. 
     In this state, when the driving gear  110  rotates in the first direction A 1 , connection between the driving gear  110  and the driving member  510  is disconnected, and the driving member  510  may freely rotate. Due to the elastic force of the elastic member  330 , the second frame  201  rotates with respect to the hinge axis  301  in a direction B 2 , and the first moving member  500  having pushed by the second frame  201  returns from the second location to the first location. The developing roller  12  returns to the development position where the developing roller  12  contacts the photosensitive drum  11 , and then the developing roller  12  remains at the development position due to the elastic force of the elastic member  330 . 
       FIG. 17  is a diagram illustrating the development cartridge  10 , according to an embodiment. Referring to  FIG. 17 , an axis  103  is mounted at the first frame  101 . A driving gear  150  to be rotated by the coupler  320  is mounted on the axis  103 . For example, the driving gear  150  is engaged with the gear  110 . The driving member  510  is rotatably mounted on the axis  103 . 
     Selective power connection between the driving member  510  and the driving gear  150  may be realized by the one-way clutch structure shown in  FIG. 6 . In this case, the driving gear  210  in  FIG. 6  may be the driving gear  150 . In addition, the selective power connection between the driving member  510  and the driving gear  150  may be realized by the one-way clutch structure shown in  FIG. 7 . In this case, the rotation axis  12   a  in  FIG. 7  may be the axis  103 . In addition, when the speed reducer is used, the driving gear  210  in  FIG. 10  may be the driving gear  150 . 
     Also, the driving gear  150  may be connected to the driving member  510  by the planetary reducer. In this case, as shown in  FIG. 7 , the bush  210   d  may be arranged at the driving gear  150 , and the sun gear  210   c  may be inserted into the bush  210   d  by having the clutch spring  530  arranged therebetween. 
     According to the aforementioned configuration, when the driving gear  150  rotates in the first direction A 1  for a printing operation, the driving member  510  does not rotate. Therefore, the first moving member  500  is located at the first location, and the photosensitive drum  11  and the developing roller  12  are located at the development position as shown in  FIG. 2 . 
     When the driving gear  150  rotates in the second direction A 2 , the driving member  510  rotates together with the driving gear  150 . Then, the first moving member  500  is switched from the first location to the second location, and the second frame  201  rotates with respect to the hinge axis  301  in a direction opposite to the elastic force of the elastic member  330 , so that the photosensitive drum  11  and the developing roller  12  are located at the non-development position where the photosensitive drum  11  and the developing roller  12  are spaced apart from each other. 
     In this state, when the driving gear  150  rotates in the first direction A 1 , the connection between the driving gear  150  and the driving member  510  is disconnected, and the driving member  510  may freely rotate. Due to the elastic force of the elastic member  330 , the second frame  201  rotates with respect to the hinge axis  301  in a direction where the photosensitive drum  11  and the developing roller  12  contact each other, and the first moving member  500  rotates the driving member  510  in the first direction A 1  and is shifted from the second location to the first location. 
     Although not illustrated, the structure of simultaneously controlling the development nip N 1  and the charging nip N 2  shown in  FIGS. 14 and 15  may also be applied to the embodiments of  FIGS. 16 and 17 . 
     While this disclosure has been particularly shown and described with reference to the embodiments thereof, it will be understood by one of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims. The embodiments should be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the disclosure is defined not by the detailed description of the disclosure but by the appended claims, and all differences within the scope will be construed as being included in the disclosure.