Abstract:
A multi-passing apparatus to repeatedly transfer a recording medium to an image forming unit to realize a high resolution image and an image forming apparatus including the multi-passing apparatus. The multi-passing apparatus includes a feeding passageway extending from a feeding unit to an image forming unit, a divergent passageway extending from the feeding passageway to support a repeated transfer of a recording medium, and a guide unit to align a front end of the recording medium as the recording medium is transferred through the feeding passageway, and to guide the recording medium so that the recording medium passing the image forming unit for the first time is fed to the divergent passageway.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 10-2006-0055544, filed on Jun. 20, 2006, the entire content of which is incorporated herein in its entirety by reference. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present general inventive concept relates to an image forming apparatus, and more particularly, to a multi-passing apparatus to repeatedly transfer a recording medium to an image forming unit and an image forming apparatus having the same. 
         [0004]    2. Description of the Related Art 
         [0005]    Image forming apparatus can be classified into electrophotographic image forming apparatus and ink-jet image forming apparatus. The electrophotographic image forming apparatus forms image information as a latent image on a photosensitive body and transfers the image information onto a recording medium to indirectly form an image. The inkjet image forming apparatus directly transfers or sprays a developer onto a recording medium to form an image. 
         [0006]    Such image forming apparatus may skip printing on certain areas of a recording medium due to an inferiority of an image forming unit. Thus, the image quality may be deteriorated. 
         [0007]    Accordingly, it is necessary for the image forming apparatus to prevent the occurrence of such non-printed areas, by transferring the recording medium to the image forming unit repeatedly. 
       SUMMARY OF THE INVENTION 
       [0008]    The present general inventive concept provides a multi-passing apparatus to repeatedly transfer a recording medium, and an image forming apparatus having the multi-passing apparatus. 
         [0009]    The present general inventive concept also provides a multi-passing apparatus to guide a recording medium to an image forming passage repeatedly, and to align a front end of the recording medium so that the recording medium is not skewed, and an image forming apparatus having the multi-passing apparatus. 
         [0010]    Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept. 
         [0011]    The foregoing and/or other aspects and utilities of the present general inventive concept are achieved by providing a multi-passing apparatus including a feeding passageway extending from a feeding unit to an image forming unit, a divergent passageway extending from the feeding passageway to support a repeated transfer of a recording medium, and a guide unit to align a front end of the recording medium as the recording medium is transferred through the feeding passageway, and to guide the recording medium so that the recording medium passing the image forming unit for the first time is fed to the divergent passageway. 
         [0012]    The guide unit may include at least one guide member formed at the junction of the feeding passageway and the divergent passageway to move between first and second positions, wherein the first position is to transfer the recording medium, with the front end being aligned, and the second position is to connect the feeding passageway with the divergent passageway to form a path through which the recording medium is repeatedly transferred. 
         [0013]    The guide unit may further include an elastic member to urge the guide members to maintain the second position. 
         [0014]    The guide member may include an aligning surface formed on a first side to align the recording medium, and a guide surface formed on a second side to guide the recording medium to the divergent passageway. 
         [0015]    The guide member may include a pair of guide members, which are connected to each other by a bracket. 
         [0016]    The foregoing and/or other aspects and utilities of the present general inventive concept are also achieved by providing an image forming apparatus including an image forming unit, a feeding unit to load a recording medium to be fed to the image forming unit, and a multi-passing device to align a front end of the recording medium to feed the recording medium to the image forming unit and to guide the repeated transfer of the recording medium. 
         [0017]    The multi-passing device may include a feeding passageway extending from a feeding unit to an image forming unit, a divergent passageway extending from the feeding passageway to support the repeated transfer of a recording medium, and a guide unit to align a front end of the recording medium as the recording medium is transferred through the feeding passageway, and to guide the recording medium so that the recording medium passing the image forming unit for the first time is fed to the divergent passageway. 
         [0018]    The guide unit may include at least one guide member formed at the junction of the feeding passageway and the divergent passageway to move between first and second positions, wherein the first position is to transfer the recording medium, with the front end being aligned, and the second position is to connect the feeding passageway with the divergent passageway to form a path through which the recording medium is repeatedly transferred. 
         [0019]    The guide unit may further include an elastic member maintaining the guide members in the second position. 
         [0020]    The guide member may include an aligning surface formed on a first side to align the recording medium, and a guide surface formed on a second side to guide the recording medium to the divergent passageway. 
         [0021]    The guide member may include a pair of guide members, which are connected to each other by a bracket. 
         [0022]    The foregoing and/or other aspects and utilities of the present general inventive concept are also achieved by providing a printing media supplying apparatus used with an image forming apparatus, including a feeding unit to feed the printing medium toward an image forming unit, a guide unit to control the feeding direction of the printing medium, a first feeding passageway to guide the printing medium from the feeding unit to the guide unit, a second feeding passageway to guide the printing medium from the guide unit to the printing unit, and a divergent passageway to support a reciprocating movement of the printing medium during a printing operation, the divergent passageway opening up communication with the second feeding passageway by operation of the guide unit. 
         [0023]    The guide unit may be disposed at a junction of the first and second feeding passageways to rotate between a first position to supply the printing medium towards the second feeding passageway and a second position to block the first feeding passageway and guide the printing medium towards the divergent passageway. 
         [0024]    The guide unit may include a plurality of guide members each including one or more aligning portions to align the printing medium with respect to a printing direction when the guiding unit is in the second position, and one or more first guide portions to guide the reciprocating movement of the printing medium between the divergent passageway and the second feeding passageway when the guide unit is in the second position. 
         [0025]    Each guide member may further include one or more second guide portions to guide the printing medium to the second feeding passageway as the guide unit moves from the second position to the first position. 
         [0026]    The supplying apparatus may further include an elastic member coupled to the guide unit to resiliently bias the guide unit to the second position. 
         [0027]    A driving force of the printing medium supplied toward the image forming unit by the feeding unit may push the guide unit into the first position, and the guide unit may return to the second position when the printing unit passes through the guide unit by the bias force of the elastic member. 
         [0028]    The driving force of the printing medium may align the printing medium against the guide unit, and the driving force of the printing medium may be insufficient to push the guide unit into the first position if the printing medium is not aligned with respect to a feeding direction of the printing medium. 
         [0029]    The supplying apparatus may further include a first transferring roller installed on the first feeding passageway to supply the printing medium to the second passageway, and a second transferring roller installed on the second feeding passageway to supply the printing medium to the image forming unit and to reciprocate the movement of the printing medium with respect to the image forming unit during the printing operation. 
         [0030]    The guide unit may be pivotably mounted to a rotating shaft of the first transferring roller. 
         [0031]    The foregoing and/or other aspects and utilities of the present general inventive concept are also achieved by providing a supplying apparatus, including a feeding unit to feed the printing medium toward an image forming unit, a supplying passageway to guide the printing medium toward the image forming unit, a reciprocating passageway to support a reciprocating movement of the printing medium during a printing operation, wherein the reciprocating passageway branches from the supplying passage, a guide unit, disposed on the supplying passageway, to guide the printing medium towards the reciprocating passageway during the reciprocating movement of the printing medium. 
         [0032]    The guide unit may rotate between a first position to supply the printing medium toward the image forming unit and a second position to align the printing medium and to guide the printing medium toward the reciprocating passageway. 
         [0033]    The guide unit may further include an elastic member to continually bias the guide unit to the second position, and a driving force of the printing medium supplied along the supplying passageway pushes the guide unit to the first position. 
         [0034]    The guide unit may return to the second position after the printing medium passes through the guide unit a first time. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0036]      FIG. 1  is a view illustrating a multi-passing apparatus and an image forming apparatus having the multi-passing apparatus according to an exemplary embodiment of the present general inventive concept; 
           [0037]      FIG. 2  is a view illustrating a state of a recording medium arranged and fed by the multi-passing apparatus of  FIG. 1 ; 
           [0038]      FIG. 3  is a view illustrating a state of the recording medium repeatedly transferred to an image forming unit by the multi-passing apparatus of  FIG. 1 ; 
           [0039]      FIG. 4  illustrates a plan view taken along an arrow IV of  FIG. 2 ; 
           [0040]      FIG. 5  is a perspective view illustrating the state of the recording medium arranged and fed by the multi-passing apparatus of  FIG. 1 ; and 
           [0041]      FIG. 6  is a perspective view illustrating the state of the recording medium repeatedly transferred to the image forming unit by the multi-passing apparatus of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. 
         [0043]      FIG. 1  is a view illustrating an image forming apparatus  200  having a multi-passing apparatus  100 , according to an exemplary embodiment of the present general inventive concept. Referring to  FIG. 1 , the image forming apparatus  200  includes an image forming unit  10 , a feeding unit  50 , first and second transferring rollers  31  and  32 , a delivering roller  35 , and the multi-passing apparatus  100 . The image forming unit  10  forms an image on a recording medium P. The feeding unit  50  feeds the recording medium P to the image forming unit  10 . The first and second transfer rollers  31  and  32  transfer the recording medium P fed through the feeding unit  50 . The delivering roller  35  is disposed under the image forming unit  10 . The multi-passing apparatus  100  arranges a front end of the recording medium P fed by the feeding unit  50  and guides a repeated transfer of the recording medium P. 
         [0044]    The image forming unit  10  may be an image forming unit using various image forming methods, such as an electrophotographic method using a photosensitive medium or the like, an ink-jet method using a print head or the like, or a thermal transfer method using an ink ribbon or the like. 
         [0045]    The feeding unit  50  loads the recording medium P to be fed to the image forming unit  10  therein and includes a feeding roller  51  to feed the recording medium P. 
         [0046]    Support rollers  33  and  34  are respectively disposed opposite to the first and second transferring rollers  31  and  32 . 
         [0047]    The multi-passing apparatus  100  of  FIG. 1  is also illustrated in  FIGS. 2 ,  3 ,  5 , and  6 . 
         [0048]    As illustrated in  FIGS. 1 ,  2 , and  3 , the multi-passing apparatus  100  includes a feeding passageway  110 , at least one divergent passageway  120 , and a guide unit  20 . The feeding passageway  110  is disposed to feed the recording medium P from the feeding unit  50  to the image forming unit  10 . The divergent passageway  120  diverges from a downstream portion of the feeding passageway  110 . The guide unit  20  arranges a front end P 1  (see  FIG. 2 ) of the recording medium P transferred through the feeding passageway  110  and guides the recording medium P, which has been first transferred to the image forming unit  10 , toward the divergent passageway  120 . 
         [0049]    The feeding passageway  110  extends from the feeding unit  50  to the image forming unit  10 , and the recording medium P is picked up by the feeding roller  51  of the feeding unit  50  and then guided to the image forming unit  10  through the feeding passageway  110 . 
         [0050]    The first and second transferring rollers  31  and  32  are installed on the feeding passageway  110 . The feeding passageway  110  includes first and second feeding passageway  111  and  112 . The first feeding passageway  111  extends from the feeding unit  50  to the first transferring roller  31 , and the second feeding passageway  112  extends from the first transferring roller  31  to the image forming unit  10 . Access to the first and second feeding passageways  111  and  112  by the recording medium P is controlled by the guide unit  20 . 
         [0051]    The first feeding passageway  111  includes front and rear guide surfaces  111   a  and  111   b  forming a space through which the recording medium P is transferred. The second feeding passageway  112  includes upper and lower guide surfaces  112   a  and  112   b  forming a space through which the recording medium P is transferred. 
         [0052]    The divergent passageway  120  guides the recording medium P so that the recording medium P is repeatedly transferred to the image forming unit  10 . The divergent passageway  120  may be installed so that the recording medium P is unfolded and then repeatedly transferred. In other words, the divergent passageway  120  intersects with the second feeding passageway  112 . 
         [0053]    The divergent passageway  120  includes upper and lower guide surfaces  121  and  122  forming a space through which the recording medium P is transferred. 
         [0054]    The guide unit  20  is installed to move between first and second positions S 1  and S 2  respectively illustrated in  FIGS. 2 and 3 . The guide unit  20  moves to the first position S 1  so as to feed the recording medium P to the image forming device  10  and arrange the recording medium P. The guide unit  20  moves to the second position S 2  so as to repeatedly transfer the recording medium P to the image forming unit  10 . 
         [0055]    The guide unit  20  includes at least one or more guide members. As illustrated in  FIGS. 2-6 , the guide unit  20  may include guide members  21  and  22 . The guide members  21  and  22  pivot at an intersecting point between the feeding passageway  110  and the divergent passageway  120  along a direction F 2  opposite to a direction F 1  along which the recording medium P is fed as illustrated in  FIG. 2 . 
         [0056]    The guide unit  20  may include a pair of guide members  21  and  22  which are connected to each other and pivot together by a bracket  23  as illustrated in  FIG. 4 . 
         [0057]    The guide members  21  and  22  may pivot by a recovery force of an elastic member  25  along the direction F 2  opposite to the direction F 1  along which the recording medium P is fed. The elastic member  25  may be a coil spring, a torsion spring, a plate spring, or the like. 
         [0058]    The elastic member  25  may include a first end  25   a  fixed to ends of the guide members  21  and  22  and a second end  25   b  fixed to a body of the image forming apparatus  200 . The elastic member  25  elastically urges the guide members  21  and  22  to pivot along the direction F 2  opposite to the direction F 1  along which the recording medium P is fed. 
         [0059]    The guide members  21  and  22  may be pivotably supported on a rotary shaft  31   a  of the first transferring roller  31  and pivot on the rotary shaft  31   a  of the first transferring roller  31  by the recovery force of the elastic member  25 . 
         [0060]    The guide members  21  and  22  respectively include arrangement surfaces  21   a  and  22   a  on their sides and guide surfaces  21   b  and  22   b  on other sides as illustrated in  FIGS. 2-6 . 
         [0061]    If the feeding roller  51  of the feeding unit  50  and the first transferring roller  31  are driven to feed the recording medium P through the feeding passageway  110  along the direction F 1  indicated by an arrow of  FIG. 2 , the guide members  21  and  22  pivot along the direction F 1  by a transfer force of the recording medium P to move to the first position S 1  connecting the first and second feeding passageways  111  and  112 . 
         [0062]    When the front end P 1  of the recording medium P is not arranged along a width direction in the first position S 1 , i.e. the recording medium P is skewed with respect to the width direction of the first position S 1 , the guide members  21  and  22  pivot along the direction F 2  of  FIG. 2  by the recovery force of the elastic member  25 . The guide members  21  and  22  uniformly press on the front end P 1  of the recording medium P toward the width direction due to the pivot force as illustrated in  FIG. 4  to arrange the front end P 1  of the recording medium P to an alignment position. 
         [0063]    If a rear end of the recording medium P completely passes the guide member  21  and  22 , the guide members  21  and  22  pivot along the direction F 2  of  FIG. 2  opposite to the direction F 1  of  FIG. 2  along which the recording medium P is fed due to the recovery force of the elastic member  25  so that the guide surfaces  21   b  and  22   b  of the guide members  21  and  22  move to the second position S 2  which connects the divergent passageway  120  and the second feeding passageway  112  as illustrated in  FIG. 3 . 
         [0064]    While the recording medium P is repeatedly transferred along directions R 1  and R 2  indicated by arrows in  FIG. 3  while in the second position S 2  of the guide members  21  and  22  by the movement of the second transferring roller  32 , the image forming unit  10  can form an image on the recording medium P and prevent the occurrence of non-printed areas. 
         [0065]    The guide members  21  and  22  moved to the second position S 2  close the connection between the first and second feeding passageways  111  and  112  to block the entrance of the recording medium P into the first feeding passageway  111 . 
         [0066]    As illustrated in  FIGS. 5 and 6 , insertion grooves  122   a  may be formed in the lower guide surface  122  of the divergent passageway  120  adjacent to front ends of the guide members  21  and  22 . The guide members  21  and  22  are inserted into the insertion grooves  122   a.  Thus, the divergent passageway  120  and the second feeding passageway  112  may form a further gentle guide surface. 
         [0067]    According to exemplary embodiments of the present general inventive concept, a recording medium P can be guided along an image forming passage repeatedly, and the recording medium P is well aligned with respect to a feeding direction so that it is not skewed when fed to the image forming unit. 
         [0068]    Although a few embodiments of the present general inventive concept have been illustrated and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.