Patent Publication Number: US-9417599-B2

Title: Image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/030,772, filed on Sep. 18, 2013, which is currently pending and claims the priority benefit of Korean Patent Application No. 10-2012-0119350, filed on Oct. 25, 2012 in the Korean Intellectual Property Office, the disclosures of each of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments of the present disclosure relate to an image forming apparatus having a transfer device to transfer toner to a printing medium from a plurality of developing units. 
     2. Description of the Related Art 
     An image forming apparatus represents an apparatus designed to form an image on a printing medium, and includes a printer, a copy machine, a facsimile, and a multifunctional device having the functionalities of the printer, the copy machine, and the facsimile. 
     An image forming apparatus includes a body provided at one side thereof with an opening, and a side cover rotatably installed at the body to open and close the opening. The body is provided at an inside thereof with a plurality of developing units to develop electrostatic latent images to visible images through toners according to colors, an exposure device to form an electrostatic latent image on a photoconductor of each of the developing units by irradiating light onto the photoconductor of the developing units, a transfer device to transfer the visible image developed on the photoconductor to the printing medium, and a fusing device to fix the toner to the printing medium. 
     In addition, the transfer device is movably installed at the body so as to be separated from the body through the opening. 
     SUMMARY 
     Therefore, it is an aspect of the present disclosure to provide an image forming apparatus capable of separating a transfer device from a body in a safe manner. 
     It is an aspect to provide an image forming apparatus capable of preventing a sensing unit from making friction with a transfer device when the transfer device is separated or installed. 
     Additional aspects of the disclosure 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 disclosure. 
     In accordance with an embodiment, an image forming apparatus includes a body, a transfer device and at least one locking lever. The body may be provided at one side thereof with an opening. The transfer device may be movably installed at the body so as to be detachable through the opening. The at least one locking lever may be rotatably installed at the transfer device. The locking lever may rotate between a first position at which one end of the locking lever protrudes from the transfer device and a second position at which the one end is accommodated within the transfer device. The body may include a locking protrusion that is locked with other end of the locking lever in a state that the locking lever is at the first position. 
     The image forming apparatus may further include a lever spring configured to elastically support the locking lever such that the locking lever is maintained at the first position. 
     The image forming apparatus may further include one pair of guide members configured to guide separation of the transfer device while being disposed at opposite sides of inside the body, respectively. The guide member may include the locking protrusion and a rail part on which the transfer device is movably installed. 
     The transfer device may include an intermediate transfer belt on which toners are transferred in an overlapping manner, a driving roller and a driven roller that are disposed at opposite sides of inside of the intermediate transfer belt to rotate the intermediate transfer belt, and one pair of transfer device frames which are spaced apart from each other and to which both ends of each of the diving roller and the driven roller are rotatably installed. The at least one locking lever may include one pair of locking levers rotatably installed at the one pair of transfer device frames, respectively. 
     The locking lever may be provided at one end thereof with a button part protruding toward an upper side of the transfer device, provided at other end thereof with a locking part locked with the locking protrusion, and provided at a middle portion thereof with a hinge part such that the locking lever is rotatably installed at the transfer device frame. 
     The guide member may include a depression part provided in parallel to the locking protrusion such that the locking part is moved downward. 
     The transfer device frame may include an accommodation part in which the locking lever is accommodated, and a first through-hole provided at an upper side of the accommodation part so as to allow the button part to pass therethrough. 
     The transfer device may include a frame cover configured to cover the accommodation part, and the accommodation cover may include a second through-hole allowing the locking part to pass therethrough. 
     In accordance with an aspect, an image forming apparatus includes a body, a cover, a plurality of developing units, a transfer device and a sensing unit. The body may have an opening. The cover may open and close the opening. The plurality of developing units may be configured to develop an electrostatic latent image to a visible image through toner. The transfer device may be movably installed at the body so as to be detachable through the opening. The sensing unit may be disposed at a lower side of the transfer device to check toner transferred to the transfer device. The transfer device may be detached through the opening while being movably installed at an inside the body. The sensing unit may rotate while interacting with movement of the transfer device while being rotatably installed at the body. 
     The transfer device may include an intermediate transfer belt on which visible images are transferred from the plurality of developing units in an overlapping manner, and the sensing unit may check toner on the intermediate transfer belt. 
     The image forming apparatus may further include a cam member that is rotatably installed at one side of the sensing unit to allow the sensing unit to rotate according to movement of the transfer device. 
     The transfer device may include a driving roller and a driven roller that are disposed at opposite sides of inside of the intermediate transfer belt, and one pair of transfer device frames to which both ends of each of the diving roller and the driven roller are rotatably installed. The transfer device may include a protrusion part protruding downward to interact with the cam member. 
     The cam member may include a cam part formed to be locked with the protrusion part according to the movement of the transfer device. 
     The sensing unit may include first hinge shafts formed at both side ends thereof, respectively, such that the sensing unit is rotatably installed at the body, and a second hinge shaft spaced apart from the first hinge shaft in parallel to the first hinge shaft such that the cam member is rotatably installed at the second hinge shaft. The cam member may include a hinge hole allowing the second hinge shaft to pass therethrough for installation. 
     The body may include a body frame on which the sensing unit is rotatably installed. The image forming apparatus may further include a sensor spring configured to elastically support the sensing unit such that one side of the sensing unit is maintained in a state of being supported by the body frame. 
     As is apparent from the above description, only in a state that a worker operates the locking lever while gripping the transfer device frame of the transfer device, the transfer device is separated from the body, thereby separating the transfer device in a safe manner. 
     In addition, the sensing unit rotates by movement of the transfer device, thereby preventing the sensing unit from making friction with the transfer device in a process of detaching and attaching the transfer device. 
    
    
     
       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 of which: 
         FIG. 1  is a cross sectional view of an image forming apparatus in accordance with an embodiment. 
         FIG. 2  is a cross sectional view of a process in which a transfer device is separated in the image forming apparatus in accordance with an embodiment. 
         FIG. 3  is an exploded perspective view illustrating an installation state of a transfer device and a sensor unit in the image forming apparatus in accordance with an embodiment. 
         FIG. 4  is a perspective view illustrating a guide member in the image forming apparatus in accordance with an embodiment. 
         FIG. 5  is a perspective view illustrating an installation state of a locking member in the image forming apparatus in accordance with an embodiment. 
         FIGS. 6 to 9  are side views illustrating an operation of a locking lever when a transfer device is separated in the image forming apparatus in accordance with an embodiment. 
         FIG. 10  is a perspective view illustrating an installation state of a sensor unit in the image forming apparatus in accordance with an embodiment. 
         FIG. 11  is an exploded perspective view illustrating an installation state of a sensor unit in the image forming apparatus in accordance with an embodiment. 
         FIGS. 12 and 13  are side views illustrating an operation of a sensor unit when a transfer device is separated from a body in the image forming apparatus in accordance with an embodiment. 
         FIGS. 14 and 15  are side views illustrating an operation of a sensor unit when a transfer device is installed on a body in the image forming apparatus in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
     Referring to  FIG. 1 , an image forming apparatus in accordance with an embodiment includes a body  10  forming the external appearance of the image forming apparatus, a printing medium storage unit  20  to store printing medium, a plurality of developing units  30 C,  30 M,  30 Y and  30 K to develop electrostatic latent images to visible images according to colors by use of toner, an exposure unit  40  to form electrostatic latent images by irradiating light onto photoconductors  31  of the charged developing units  30 C,  30 M and  30 Y and  30 K, a transfer device  50  to receive a printing medium from the printing medium storage unit  20  and transfer the visible image formed on the photoconductors  31  to the printing medium, a fusing unit  60  to fix the toner, which is transferred to the printing medium, to the printing medium, and a sensing unit  70  to check the toner on the intermediate transfer belt  51  of the transfer device  50 . 
     The body  10  is provided at an upper portion thereof with a loading part  10   a  on which the printing medium completed with the image formation is loaded, and a discharge port  10   b  is provided at one side of the loading part  10   a  to allow the printing medium completed with the image formation to be discharged therethrough. In addition, an opening  10   c  is provided at one side of the body  10  to repair components or replace expendable materials of an inside the body  10 , and a side cover  11  is installed to open and close the opening  10   c . In accordance with an embodiment of the present disclosure, the side cover  11  has a lower end rotatably installed at the body  10  so as to open and close the opening  10   c  while rotating on the lower end thereof. 
     The printing medium storage unit  20  includes a printing medium cassette  21  movably installed at the body  10 , a knock-up plate  22  to load the printing media while being disposed in the printing medium cassette  21 , and an elastic member  23  to elastically support the knock-up plate  22 . 
     Each of the developing units  30 C,  30 M,  30 Y and  30 K includes a photoconductor  31 , on a charged surface of which an electrostatic latent image is formed by the exposure unit  40 , a developing roller  32  to supply toner to the photoconductor  31 , and a charging unit  33  to charge the surface of the photoconductor  31 . 
     The developing units  30 C,  30 M,  30 Y and  30 K in accordance with the embodiment of the present disclosure include four developing units  30 C,  30 M,  30 Y and  30 K each storing one of toners of cyan C, magenta M, yellow Y and black K at an inside thereof, to develop one of cyan C, magenta M, yellow Y and black K colors. The four developing units  30 C,  30 M,  30 Y and  30 K are disposed at a lower side of the transfer device  50 . 
     The exposure unit  40  forms the electrostatic latent images on the surfaces of the photoconductors  31  by irradiating including image information to the photoconductors  31  provided at the developing units  30 C,  30 M,  30 Y and  30 K, respectively. 
     The transfer device  50  includes an intermediate transfer belt  51  on which visible images developed on the photoconductors  31  of the developing units  30 C,  30 M,  30 Y and  30   k  are transferred in an overlapping manner, a driving roller  52  and a driven roller  53  disposed at opposite sides of inside the intermediate transfer belt  51  to rotate the intermediate transfer belt  51 , a plurality of first transfer rollers  54  disposed opposite to the photoconductors  31  of the developing units  30 C,  30 M,  30 Y and  30 K, respectively, while interposing the intermediate transfer belt  51  therebetween, such that the visible images formed on the photoconductors  31  are transferred to the intermediated transfer belt  51 , and transfer device frames  56  on which both ends of each of the first transfer rollers  54 , the driving roller  52  and the driven droller  53  are rotatably installed. 
     Meanwhile, a second transfer roller  55  is disposed at the side cover opposite to the driving roller  52  while interposing the intermediate transfer belt  51  therebetween, to press the printing medium toward the intermediate transfer belt  51  to transfer the visible image of the intermediate transfer belt  51  to the printing media. 
     The fusing unit  60  includes a heating roller  61  to generate heat, and a pressing roller  62 , an outer circumferential surface of which is formed of elastically deformable material to press the printing medium onto an outer circumferential surface of the heating roller  61 . 
     In addition, at the body  10 , a pick-up unit  80  is disposed at an upper side of the printing medium storage unit  20  to pick up the printing media loaded on the knock-up plate  22  one by one, a delivery roller  12  to guide the printing medium, which is picked up by the pick-up unit  80 , upward, and a discharge unit  90  disposed at an upper side of the fusing unit  60  while being adjacent to the discharge port  10   b  to allow the printing medium passing through the fusing unit  60  to be discharged through the discharge port  10   b . The pick-up unit  80  includes a pick-up roller  81  to pick up the printing media located on the knock-up plate  22  one by one, and the discharge unit  90  includes one pair of discharge rollers  91  disposed at an inside the discharge port  10   b.    
     In addition, frames are provided at the body  10  to install and support the above described elements, and the frames include a body frame  13  that is disposed at a lower side of inside the opening  10   c  such that the sensing unit  70  is installed thereon. 
     Referring to  FIGS. 2 to 4 , the transfer device  50  is detachably installed at the body  10  so as to be removable from the body  10  through the opening  10   c . One pair of guide protrusions  56   a  and  56   b  are provided at each of the transfer device frames  56 , and one pair of guide members  14  each having rail parts  14   a  and  14   b  are disposed at each of opposite sides of inside of the body  10 . In accordance with this embodiment, one pair of guide protrusions  56   a  and  56   b  are provided at each of the transfer device frames  56 , and one pair of rail parts  14   a  and  14   b  are disposed in parallel to each other in a upper and lower side direction. 
     Referring to  FIGS. 5 and 6 , the transfer device  50  includes a locking lever  57  configured to enable a worker to separate the transfer device  50  from the body  10  in a safe manner, and a lever spring  58  configured to elastically support the locking lever  57  to maintain the locking lever  57  in a state of being rotated in one direction. 
     The locking lever  57  is rotatably installed at one of the two transfer device frames  56  of the transfer device  50  so as to be rotatable between a first position at which one end of the locking lever  57  protrudes from the transfer device  50  and a second position at which the one end of the locking lever  57  is accommodated within the transfer device  50 . 
     The one end of the locking lever  57  protruding from the transfer device  50  is provided with a button part  57   a  to which a worker applies force to rotate the locking lever  57 , and the other end of the locking lever  57  is provided with a locking part  57   b  configured to be locked with the guide member  14  to limit the movement of the transfer device  50 , and a hinge part  57   c  formed in a middle portion of the locking lever  57  such that the locking lever  57  is rotatably installed at the transfer device frame  56 . 
     The lever spring  58  elastically supports the locking lever  57  such that the locking lever  57  is rotated to the first position and is maintained at the first position. 
     For installation of the locking lever  57 , an accommodation part  56   c  is provided at one side of the transfer device frame  56 , and an accommodation part cover  59  is installed at the transfer device frame  56  to cover and hide the accommodation part  56   c . A first through-hole  56   d  allowing the button part  57   a  to pass therethrough is provided at an upper surface of the transfer device frame  56 , and a second through-hole  59   a  allowing the locking part  57   b  to pass therethrough is provided at the accommodation part cover  59 . 
     Referring to  FIG. 4 , the guide member  14  is provided at a lower portion thereof with a depression part  14   c  depressed downward such that the locking part  57   b  is moved downward according to movement of the transfer device  50 , and a locking protrusion  14   d  which is provided in line with the depression part  14   c  and to which the locking part  57   b  of the locking lever  57  is locked. 
     Accordingly, in a state in which the transfer device  50  is installed at an inside the body as shown in  FIG. 6 , when a user pulls the transfer device  50  to the outside the opening  10   c  through the opening  10   c  to separate the transfer device  50 , the transfer device  50  is guided by the rail parts  14   a  and  14   b  of the guide member  14  and moved as shown in  FIG. 7 , and if the locking part  57   b  reaches the position of the depression part  14   c  as shown in  FIG. 8 , the locking lever  57  is rotated from the second position to the first position by the elastic restoring force of the lever spring  58 , and thus button part  57   a  protrudes to the upper side of the first through-hole  56   d  and the locking part  57   b  moves downward to enter the inside of the depression part  14   c . In this manner, the locking part  57   b  entering the inside of the depression part  14   c  is locked with the locking protrusion  14   d , thereby limiting the movement of the transfer device  50 . 
     In order to move the transfer device  50  again, the locking part  57   b  needs to be separated from the depression part  14   c  be moving upward. Accordingly, a worker needs to press the button part  57   a  while gripping the transfer device frame  56  of the transfer device  50 , and if the worker presses the button part  57   a , the locking lever  57  is rotated from the first position to the second position as shown in  FIG. 9 , and accordingly, the locking part  57   b  is separated from the depression part  14   c , thereby enabling the transfer device  50  to be moved again. 
     Accordingly, when the worker pulls the transfer device  50  to the outside of the opening  10   c , the transfer device  50  is withdrawn through the opening  10   c  and is completely separated from the body  10 . 
     In a process of withdrawing the transfer device  50  as the above, the worker needs to maintain a state of having the button part  57   a  pressed while gripping the transfer device frame  56 , so that the worker needs to withdraw the transfer device  50  in a state of gripping the transfer device frame  56 . Accordingly, the worker may separate the transfer device  50  from the body  10  in a safe manner. 
     Referring to  FIGS. 10 and 11 , the sensing unit  70  includes a sensor  71  disposed opposite to the intermediate transfer belt  51  to check the toner on the intermediate transfer belt  51 . In this embodiment of the present disclosure, three sensors  71  are provided and disposed while being spaced apart from one other in a width direction of the intermediate transfer belt  51 . 
     The sensing unit  70  is disposed at a lower side of the transfer device  50 , and rotatably installed at the body frame  13  so as to be rotated according to the movement of the transfer device  50 . Such a configuration enables the sensing unit  70  to be disposed adjacent to the intermediate transfer belt  51  while preventing the sensing unit  70  from being in friction with the intermediate transfer belt  51  upon detaching the transfer device  50 . 
     In order for the sensing unit  70  to rotate while interacting with the movement of the transfer device  50 , a cam member  72  is rotatably installed at one side of the sensing unit  70 . In addition, in order to maintain the sensing unit  70  in a state of having the sensor  71  disposed opposite the intermediate transfer belt  51  when an external force does not exert, a sensor spring  73  is provided to elastically support the sensing unit  70  toward the body frame  13 . The sensor spring  73  has one end connected to a second hinge shaft  70   b , which is to be described later, and the other end connected to the body frame  13 . 
     Meanwhile, a protrusion part  56   e  protrudes downward from a lower portion of one side end of the transfer device frame  56  adjacent to the opening  10   c , and configured to interact with the cam member  72  while making contact with the cam member  62  according to movement of the transfer device  50 . 
     First hinge shafts  70   a  are provided at both ends of the sensing unit  70 , respectively, so that the sensing unit  70  is rotatably installed at the body frame  13 . The sensing unit  70  is provided at one of both side ends thereof with a second hinge shaft  70   b  that is formed while being spaced apart from the first hinge shaft  70   a  in parallel to the first hinge shaft  70   a  such that the cam member  72  is rotatably installed at the second hinge shaft  70   b.    
     The cam member  72  includes a hinge hole  72   a  allowing the second hinge shaft  70   b  to pass therethrough for installation, and a cam part  72   b  protruding toward the body frame  13  so as to be locked with the protrusion part  56   e  of the transfer device frame  56  according to movement of the transfer device  50 . 
     Accordingly, when a worker pulls the transfer device  50  to the outside the opening  10   c  to withdraw the transfer device  50  from the body  10 , the protrusion part  56   e  provided on the transfer device frame  56  applies force to the inner side of the cam part  72   b  of the cam member  72  as shown in  FIG. 12  and thus the cam member  72  rotates clockwise as shown in  FIG. 13  to cause the sensing unit  70  to rotate on the first hinge shaft  70   a  clockwise. According to the rotation of the sensing unit  70 , the upper surface of the sensing unit  70  becomes spaced apart from the lower surface of the transfer device  50 , so that the sensing unit  70  is prevented from making contact with the intermediate transfer belt  51  when the transfer device  50  is separated from the body  10 . 
     On the contrary, when the worker pushes the transfer device  50  to the inside the opening  10   c  to install the transfer device  50  in the body  10 , as shown in  FIG. 14 , the protrusion part  56   e  provided on the transfer device frame  56  applies force to the outer side of the cam part  72   b  of the cam member  72 , and thus the cam member  72  rotates toward the inside the opening  10   c . As the cam member  2  rotates at a predetermined angle, the cam part  72   b  of the cam member  72  is supported by the body frame  13 , and at this time, if the protrusion part  56   e  continues to transfer force through the cam part  72   b , as shown in  FIG. 15 , the cam member  72  is rotated counterclockwise on the second hinge shaft  70   b  at the same time when the sensing unit  70  is rotated clockwise on the first hinge shaft  70   a . According to the rotation of the sensing unit  70 , the upper surface of the sensing unit  70  becomes spaced apart from the lower surface of the transfer device  50 , so that the sensing unit  70  is prevented from making contact with the intermediate transfer belt  51  when the transfer device  50  is installed on the body  10 . 
     Although a few embodiments have been shown and described, it would 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 disclosure, the scope of which is defined in the claims and their equivalents.