Abstract:
An image forming apparatus includes a body, a photosensitive drum, an openable and closable member openably and closably formed at the body and having a transfer roller which is opposed to the photosensitive drum and transfers an image onto a printing medium, a printing medium pushing member pushing the printing medium to an outside of the body in association with an opening and a closing of the openable and closable member, an elastic member elastically supporting the printing medium pushing member to the outside of the body, and a pressing member formed at one side of the openable and closable member to press the printing medium pushing member toward an inside of the body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 2005-94588, filed on Oct. 7, 2005, the entire contents of which are hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a printing medium feeding apparatus and an image forming apparatus using the same. More particularly, the present invention relates to a printing medium feeding apparatus in which a printing medium jam in a printing medium feeding passage can be easily removed, and an image forming apparatus using the same.  
         [0004]     2. Description of the Related Art  
         [0005]     Generally, an image forming apparatus has an openable and closable guide member which guides a printing medium onto a paper medium feeding passage. If a printing medium jams in the paper medium feeding passage, the guide member is opened to remove the printing medium. However, if a long printing medium is jammed between a feeding roller upstream of the paper medium feeding passage and a feeding roller downstream of the paper medium feeding passage, or if the printing medium is stuck to the paper medium feeding passage by static electricity, it is difficult to pull the printing medium out of the image forming apparatus body.  
         [0006]     There have been various attempts to address these problems. Japanese Patent Publication No. 9-290942, which is hereby incorporated by reference in its entirety, discloses one example of a printing medium feeding apparatus which attempts to address these problems.  FIG. 1  shows the structure of the printing medium feeding apparatus of the image forming apparatus disclosed by Japanese Patent Publication No. 9-290942.  
         [0007]     Referring to  FIG. 1 , a guide member  8  forming a part of a paper medium feeding passage of an image forming apparatus is opened toward the outside of the image forming apparatus body to expose the paper medium feeding passage so that a printing medium  2  may be removed. The image forming apparatus further comprises a paper medium push-out member  21  for pushing out a paper medium from the inside to the outside of the paper medium feeding passage. An interlocking mechanism  22  operates the paper medium push-out member  21  as the guide member  8  is opened.  
         [0008]     One end of the interlocking mechanism (or linking member)  22  is spaced away from a first point  15  of the guide member  8  by a certain interval. The other end of the linking member  22  has an elongated hole  22   a  so that a shaft  21   b  spaced a certain interval away from a second point  20  of the printing medium push-out member  21  is inserted into the elongated hole  22   a  and slides in the elongated hole  22   a.    
         [0009]     The printing medium push-out member  21  is supported by a spring  23 . A leading end portion  21   a  of the printing medium push-out member  21  forms a part of the guide member  8  as the printing medium is fed.  
         [0010]     The image forming apparatus includes printing medium supply rollers  4  and  5 , a feeding roller  10 , and registration rollers  11 ,  12 .  
         [0011]     With this structure, the guide member  8  pivots toward the outside of the image forming apparatus body and the end portion of the elongated hole  22   a  of the interlocking mechanism  22  contacts the shaft  21   b  so that the printing medium push-out member  21  can be drawn out. Accordingly, the printing medium  2  in front of the printing medium push-out member  21  can be drawn out by the leading end  21   a  of the printing medium push-out member  21 .  
         [0012]     However, the structure of the printing medium push-out member  21  and the interlocking mechanism  22  of the above-described conventional image forming apparatus is very complicated.  
         [0013]     Accordingly, there is a need for a printing medium feeding apparatus which allows for removal of paper jams with a less complicated structure.  
       SUMMARY OF THE INVENTION  
       [0014]     An aspect of the present invention is to address at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a printing medium feeding apparatus in which a jammed printing medium can be easily removed.  
         [0015]     Another object of the present invention is to provide an image forming apparatus using the printing medium feeding apparatus.  
         [0016]     In accordance with an aspect of the present invention, an image forming apparatus comprises a body, a photosensitive drum disposed in the body, and an openable and closable member disposed on the body. The openable and closable member comprises a transfer roller disposed opposite to the photosensitive drum. A printing medium pushing member pushes the printing medium towards an outside of the body in association with an opening of the openable and closable member. An elastic member biases the printing medium pushing member towards the outside of the body, and a pressing member is formed at one side of the openable and closable member for pressing the printing medium pushing member towards the inside of the body.  
         [0017]     The printing medium pushing member may comprise a support portion hinged to the body, and a printing medium pushing portion extending from one end of the support portion to push the printing medium.  
         [0018]     The elastic member may comprise a wire spring, and a first end of the elastic member may be connected with the printing medium pushing member and a second end of the elastic member may be with the body.  
         [0019]     The wire spring may comprise a hook portion and a lock portion.  
         [0020]     The support portion of the printing medium pushing member may comprise a wire spring locking portion to accommodate the hook portion of the wire spring, and the support portion may have a groove to accommodate an outer surface of the lock portion of the wire spring.  
         [0021]     The pressing member may comprise a pressing protrusion for contacting the support portion of the printing medium pushing member.  
         [0022]     A registration unit may be disposed upstream of the photosensitive drum for aligning a leading end of the printing medium, and a fixing unit may be disposed downstream of the photosensitive drum for fixing an image onto the printing medium.  
         [0023]     The printing medium pushing member may be disposed between the registration unit and the photosensitive drum on a printing medium feeding passage.  
         [0024]     In accordance with another aspect of the present invention, a printing medium feeding apparatus of an image forming apparatus comprises an openable and closable member adapted to be disposed on a body of an image forming apparatus, the openable and closable member forming a portion of a printing medium feeding passage, the openable and closable member exposing the printing medium feeding passage when opened, a printing medium pushing member for pushing a printing medium away from the printing medium feeding passage in cooperation with the openable and closable member, an elastic member biasing the printing medium pushing member away from the printing medium feeding passage, and a pressing member formed at one side of the openable and closable member for pressing the printing medium pushing member towards the printing medium feeding passage.  
         [0025]     The printing medium pushing member may comprise a support portion hinged to the body, and a printing medium pushing portion extending from one end of the support portion to push the printing medium.  
         [0026]     The elastic member may comprise a wire spring, and a first end of the elastic member may be connected with the printing medium pushing member and a second end of the elastic member may be connected with the body.  
         [0027]     The wire spring may comprise a hook portion and a lock portion.  
         [0028]     The support portion of the printing medium pushing member may comprise a wire spring locking portion to accommodate the hook portion of the wire spring, and the support portion may have a groove to accommodate an outer surface of the lock portion of the wire spring.  
         [0029]     The openable and closable member may further comprise a first feeding roller for feeding the printing medium and a second feeding roller which is opposed to the first feeding roller.  
         [0030]     The pressing member may comprise a pressing protrusion for contacting the support portion of the printing medium pushing member.  
         [0031]     In accordance with another aspect of the present invention, an image forming apparatus comprises a body and a photosensitive drum for forming images disposed on the body. A transfer roller is disposed opposite to the photosensitive drum to form a transfer nip. A means for registering a printing medium is disposed upstream of the photosensitive drum, and a means for fixing an image on a printing medium disposed downstream of the photosensitive drum. The photosensitive drum, transfer roller, registration means, and fixing means define a printing medium feeding path. A pushing member pushes the printing medium away from the printing medium feeding path, and is biased away from the printing medium feeding path. An openable and closable member is disposed on the body for exposing a portion of the printing medium feeding path. The openable and closable member comprising a pressing member for pressing the printing medium pushing member towards the printing medium feeding path.  
         [0032]     The printing medium pushing member may comprise a support portion pivotably disposed on the body, and a printing medium pushing portion extending from the support portion to push the printing medium.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]     The above and other objects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:  
         [0034]      FIG. 1  is a view of a printing medium feeding apparatus of a conventional image forming apparatus;  
         [0035]      FIG. 2  is a view of part of a structure of an image forming apparatus according to an exemplary embodiment of the present invention;  
         [0036]      FIG. 3  is a view of the image forming apparatus of  FIG. 2  when an openable and closable member is opened;  
         [0037]      FIG. 4  is an enlarged view of a printing medium pushing member according to an exemplary embodiment of the present invention; and  
         [0038]      FIG. 5  is an exploded perspective view of the printing medium pushing member shown in  FIG. 4 . 
     
    
       [0039]     Throughout the drawings, the same reference numerals will be understood to refer to the same elements, features, and structures.  
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0040]     The matters defined in the description such as a detailed construction and elements are provided to assist in a comprehensive understanding of the embodiments of the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.  
         [0041]      FIG. 2  is a view of part of a structure of an image forming apparatus according to an exemplary embodiment of the present invention, and  FIG. 3  is a view of the image forming apparatus of  FIG. 2  when an openable and closable member is opened.  
         [0042]     Referring to  FIGS. 2 and 3 , a photosensitive drum  103  is provided in an image forming apparatus body  101 . A transfer roller  105  is disposed opposite the photosensitive drum  103  so that an image is transferred onto a printing medium P which passes between the transfer nip formed between the photosensitive drum  103  and the transfer roller  105 .  
         [0043]     The transfer roller  105  is disposed on an openable and closable member  107  which opens a part of the image forming apparatus body  101 . One end of the openable and closable member  107 is hinged so that it pivots about a hinge axis  109 . The openable and closable member  107  may be pivoted by a certain angle so as to open and close the image forming apparatus body  101 . The transfer roller  105  with contacts or is separated from the photosensitive drum  103  depending on whether the openable and closable member  107  is opened or closed.  
         [0044]     A registration unit  110  is further included upstream of the photosensitive drum  103 . Upstream refers to a direction opposite the printing medium P feeding direction, that is, the direction opposite to the direction of the arrow A in  FIG. 2 . The registration unit  110  registers a printing medium by temporarily stopping the printing medium P before the printing medium P is fed to the transfer roller  105  to align a leading end of the printing medium P. The registration unit  110  comprises a drive registration roller  111  and an idle registration roller  113 .  
         [0045]     A fixing unit  130  is included downstream of the photosensitive drum  103 . The fixing unit  130  heats and presses the image transferred onto the printing medium P by the transfer roller  105  and comprises a heat roller  131  and a press roller  133 .  
         [0046]     A printing medium pushing member  150  is formed between the registration unit  110  and the photosensitive drum  103  on the printing medium P feeding passage. The printing medium pushing member  150  is rotated to the outside of the image forming apparatus body  101  as the openable and closable member  107  is opened so as to push the printing medium P to the outside of the image forming apparatus body  101  and provide a space in which a user can easily pull out the printing medium P. The openable and closable member  107  has a pressing member  160  that interferes with the printing medium pushing member  150 . The pressing member  160  comprises a pressing protrusion  161 .  
         [0047]      FIG. 4  is an enlarged view of the printing medium pushing member  150  according to an exemplary embodiment of the present invention, and  FIG. 5  is an exploded perspective view of the printing medium pushing member  150 .  
         [0048]     Referring to  FIGS. 4 and 5 , the printing medium pushing member  150  comprises a supporting portion  153  rotatably connected with one side of the image forming apparatus body  101  about a hinge axis  151 , and a printing medium pushing portion  155  bent at one end of the supporting portion  153  to push the printing medium P.  
         [0049]     An elastic member  170  biases the printing medium pushing member  150  towards the outside of the image forming apparatus body  101 . At this time, if the openable and closable member  107  is closed, the pressing protrusion  161 , which forms the pressing member  160  in the openable and closable member  107 , contacts the supporting member  153  so that the elastic member  170  is pressed (refer to  FIG. 2 ).  
         [0050]     In contrast, if the openable and closable member  107  is opened, the pressing protrusion  161  is separated from the supporting portion  153  so that the printing medium pushing member  150  is rotated towards the outside of the image forming apparatus body  101  by a restitution force of the elastic member  170  and the printing medium P is pushed towards the outside of the image forming apparatus body  101  (refer to  FIG. 3 ).  
         [0051]     the elastic member  170  may be formed in various configurations; however, in the present exemplary embodiment, the elastic member comprises a wire spring  171 . One end of the wire spring  171  comprises a hook portion  171   a  and a lock portion  171   b  disposed on the support portion  153  of the printing medium pushing member  150 . The wire spring may be formed, for example, by a number of bending operations.  
         [0052]     To fix the wire spring  171 , a wire spring locking portion  157  is formed at one side of the support portion  153  of the printing medium pushing member  150  to lock the hook portion  171   a  of the wire spring  171 , and a groove  159  is formed at the support portion  153  to receive an outer surface of the lock portion  171   b  of the wire spring  171 .  
         [0053]     A first end of the wire spring  171  is connected with the printing medium pushing member  150  and a second end of the wire spring  171  is connected with one side of the image forming apparatus body  101 .  
         [0054]     The operation of removing a jammed printing medium from the image forming apparatus according to an exemplary embodiment of the present invention will now be described.  
         [0055]     Referring to  FIG. 2 , as an image forming operation is performed, the leading end of the printing medium P fed by a printing medium feeding unit (not shown) is aligned by the registration unit  110 . Then, the printing medium P is fed to the transfer nip between the photosensitive drum  103  and the transfer roller  107  so that an image is transferred to the printing medium P. The fixing unit  130  heats and presses the transferred image to fix the image on the printing medium P.  
         [0056]     While the image forming operation is performed, the openable and closable member  107  is closed and the pressing protrusion  161 , which is the pressing member  160  in the openable and closable member  107 , presses the support portion  153  of the press medium pushing member  150 . Accordingly, the printing medium pushing member  150  does not interfere with the printing medium feeding passage.  
         [0057]     Referring to  FIG. 3 , if the printing medium P is jams during the image forming operation, the openable and closable member  107  is opened. The pressing protrusion  161  of the openable and closable member  107  is separated from the support portion  153  of the printing medium pushing member  150 . Accordingly, the printing medium pushing member  150  is rotated towards the outside of the image forming apparatus body  101  by a restitution force of the wire spring  171 , which is the elastic member  170 , so that the printing medium P is pushed towards the outside of the image forming apparatus body  101 . Accordingly, the printing medium P forms a curl C so that a space is formed to easily remove the jammed printing medium. With the space, the printing medium P can be easily pulled out from the image forming apparatus body  101 .  
         [0058]     In the present exemplary embodiment, the printing medium pushing member  150  is disposed between the photosensitive drum  103  and the registration unit  110 , and the transfer roller  107  is disposed opposite the photosensitive drum  103 .  
         [0059]     However, this is only an example of a suitable configuration. The printing medium pushing member  150  may be formed at any position on the printing medium feeding passage. In other words, the printing medium pushing member  150  may be applied to any type of image forming apparatus in which the printing medium feeding passage is opened to remove a printing medium P.  
         [0060]     As described above, if a printing medium P is jammed and the openable and closable member is opened, the printing medium is pushed towards the outside of the image forming apparatus body so that a user can easily pull out the printing medium.  
         [0061]     While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.