Abstract:
A photosensitive belt installation device of an electrophotographic image forming apparatus that includes a soft cartridge which rolls up for storage, and an installation guide member which selectively attaches to the image forming apparatus. When unrolled, the cartridge, allows the simple installation of a photosensitive belt into the imaging forming apparatus. The soft cartridge is a flexible cartridge having a shape of the endless track of a belt unit of the imaging forming apparatus, and is open on both sides. The unrolled soft cartridge supports the photosensitive belt during installation, as one open side of the soft cartridge is fitted over a sloping surface of the installation guide member attached to the front frame of the belt unit. The soft cartridge is completely pushed around the belt unit along a sloping surface of the installation guide member. The photosensitive belt remains around the belt unit as the soft cartridge is pulled out. The installation guide member is then be removed from the front of the belt unit.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a photosensitive belt cartridge for keeping a photosensitive belt to be installed in an electrophotographic image forming apparatus, and a photosensitive belt installation device and method employing the same. Korean Patent Application No. 00-39092, filed Jul. 8, 2000, is incorporated herein in its entirety by reference.  
           [0003]    2. Description of the Related Art  
           [0004]    As shown in FIG. 1, an electrophotographic image forming apparatus such as a color laser printer includes a photosensitive belt  10  circulating around a continuous loop while supported by a plurality of rollers  11 ,  12 , and  13  installed in a main body of the image forming apparatus. On one surface of the photosensitive belt  10 , an image to be printed is developed by a developing unit  15 , and the developed image is dried while passing by a drying unit  16 , and then is printed on a paper sheet at a transfer unit  14  including a transfer roller  14   a  and a fuser roller  14   b.  Here, the unit around which the photosensitive belt  10  circulates is called a belt unit.  
           [0005]    However, as such a photosensitive belt  10  is used for a long time, a developed image gradually deteriorates in its precision. Therefore, when the photosensitive belt  10  reaches the end of its usable life, the photosensitive belt  10  must be replaced with a new one to continue to develop a neat image. However, in order to replace the photosensitive belt  10  in a conventional method, the photosensitive belt  10  is replaced by fitting it directly by hand in its installation position within the main body of the apparatus. In this method, one  13  of the plurality of rollers  11 ,  12 , and  13  is installed to be movable as shown in dotted lines in FIG. 1, and when replaced, the photosensitive belt  10  is loosened by moving the roller  13  to the position shown in dotted lines, and then is removed from its installation position by hand. Subsequently, after a new photosensitive belt is inserted into its installation position by hand, the new photosensitive belt is tensioned by moving the roller  13  to its original position.  
           [0006]    However, since the shape of the endless photosensitive belt  10  is not a rigid patterned shape, and the endless photosensitive belt  10  is as flexible as paper, there are problems in that to replace the photosensitive belt  10  by fitting it in place by hand is bothersome and difficult in itself, and, in addition, the photosensitive belt  10  may be erroneously installed depending upon a worker who performs the replacing job.  
           [0007]    Therefore, to solve those problems, a cartridge  20  for receiving such a photosensitive belt  10  as shown in FIG. 2 has been proposed. The main body of the photosensitive belt cartridge  20  is comprised of a hard case having a shape similar to the endless track of the belt unit, and leaf springs  21  installed at the inner circumferential surface of the cartridge  20  and supporting the photosensitive belt  10  in a continuous loop state (i.e., in a state as the photosensitive belt  10  is installed around the belt unit). Reference symbol S denotes spare space provided so that the roller  13  can be moved to tension the photosensitive belt  10  when the photosensitive belt  10  is installed around the belt unit. Therefore, when the photosensitive belt  10  is installed, the cartridge  20  receiving the photosensitive belt  10  is pushed on, in the direction of arrow “A,” around the belt unit within the image forming apparatus. When the roller  13  is moved as much as the spare space (S) as shown in FIG. 3, the photosensitive belt  10 , supported by the leaf springs  21 , is tightly tensioned. At this time, when the cartridge  20  is pulled back toward the outside, only the photosensitive belt  10  remains around the belt unit.  
           [0008]    When the above hard-case cartridge  20  is used, the photosensitive belt  10  can be conveniently installed as described above. However, it is a problem to store the cartridge  20 . That is, since the cartridge  20  has nearly the same shape as that of the belt unit around which the photosensitive belt  10  circulates in an endless belt state, the volume of the cartridge is larger than the belt unit, and there is no way to reduce the volume any more due to the hard case of the cartridge  20 . Therefore, although the photosensitive belt  10  can be safely stored, and be easily installed, it is troublesome to store the cartridge  20 .  
         SUMMARY OF THE INVENTION  
         [0009]    To solve the above problem, it is an objective of the present invention to provide a photosensitive belt cartridge adapted to occupy small space during storage, and to be used in replacing a photosensitive belt in a convenient and fast manner, and a photosensitive belt installation device and method employing the same.  
           [0010]    Accordingly, to achieve the above objective, there is provided a photosensitive belt cartridge of an electrophotographic image forming apparatus including: a soft cartridge which has the endless track shape of a belt unit of the image forming apparatus, which receives a photosensitive belt therein in the endless track shape, which can be rolled up with the photosensitive belt received therein, and which has flexibility so that the rolled-up soft cartridge can be restored back to its original shape when an external force is removed; and a hard cartridge in which the soft cartridge is stored in a rolled-up state.  
           [0011]    In addition, there is provided a photosensitive belt installation device of an electrophotographic image forming apparatus for assisting in the installation of a photosensitive belt around a belt unit within the image forming apparatus comprising: an installation guide member which is attached to a front frame of the belt unit when the photosensitive belt is installed, and which has a sloping surface gradually enlarging in a direction from the outside of the image forming apparatus to the belt unit; and a soft cartridge in which the photosensitive belt to be installed around the belt unit is supported by predetermined restricting means in the endless track shape. The soft cartridge is a flexible cartridge having a shape of the endless track of the belt unit, and is open on both sides. The soft cartridge is shaped so that one open side of the soft cartridge fits over the sloping surface of the installation guide member. The soft cartridge is completely pushed around the belt unit along the sloping surface, and, then, the soft cartridge is pulled out and the photosensitive belt is freed from the restricted state by the restricting means, with the photosensitive belt formerly received in the soft cartridge remaining around the belt unit.  
           [0012]    In addition, there is provided a photosensitive belt installation method of an electrophotographic image forming apparatus for installing a photosensitive belt around a belt unit within the image forming apparatus including the steps of: preparing a soft cartridge which is a flexible cartridge having a shape of the endless track of the belt unit, which is open on both sides, and in which the photosensitive belt to be installed around the belt unit is supported by predetermined restricting means in the endless track shape; installing an installation guide member which has a sloping surface gradually enlarging in a direction from the outside of the image forming apparatus to the belt unit at the front frame of the belt unit; fitting one open side of the soft cartridge to the sloping surface of the installation guide member, and completely pushing the soft cartridge around the belt unit along the sloping surface; and causing the photosensitive belt received in the soft cartridge to remain around the belt unit by pulling out the soft cartridge from the image forming apparatus after the photosensitive belt is freed from the restricted state by the restricting means.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The above objective and advantage of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:  
         [0014]    [0014]FIG. 1 is a schematic diagram illustrating essential portions of a general electrophotographic image forming apparatus;  
         [0015]    [0015]FIGS. 2 and 3 are perspective and front views illustrating a conventional cartridge for storing and installing a photosensitive belt;  
         [0016]    [0016]FIG. 4 is a perspective view illustrating a photosensitive belt cartridge according to the present invention;  
         [0017]    [0017]FIG. 5 is a perspective view illustrating a soft cartridge of the photosensitive belt cartridge shown in FIG. 4 in an expanded state;  
         [0018]    [0018]FIG. 6 is a plan view illustrating a band member of the photosensitive belt cartridge shown in FIG. 4;  
         [0019]    [0019]FIG. 7 is a perspective view illustrating an engagement-hole portion of the photosensitive belt cartridge shown in FIG. 4, into which an engagement portion of the band member shown in FIG. 6 is inserted;  
         [0020]    [0020]FIG. 8 is a perspective view illustrating a belt unit around which a photosensitive belt is installed;  
         [0021]    [0021]FIG. 9 is a perspective view illustrating the belt unit of FIG. 8 to which an installation guide member is installed;  
         [0022]    [0022]FIG. 10 is a perspective view illustrating the installation guide member shown in FIG. 9;  
         [0023]    [0023]FIG. 11 is a perspective view illustrating the operation of fitting the soft cartridge of FIG. 5 to the belt unit of FIG. 8;  
         [0024]    [0024]FIG. 12 is a perspective view illustrating the belt unit to which the soft cartridge has been fitted; and  
         [0025]    [0025]FIG. 13 is a perspective view illustrating the belt unit around which the photosensitive belt has been installed after the soft cartridge with the soft cartridge removed. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    [0026]FIGS. 4 and 5 show the structure of a photosensitive belt cartridge of an electrophotographic image forming apparatus according to the present invention. As shown in FIGS. 4 and 5, a photosensitive belt cartridge according to the present invention includes a cylindrical hard cartridge  200 , and a soft cartridge  100  receiving a photosensitive belt  10  and stored in the hard cartridge  200  in a rolled-up state.  
         [0027]    The soft cartridge  100  is made of a flexible material such as polyethylene film or PVC film, and is not plastically deformed even though it is rolled up as shown in FIG. 4. Therefore, when an external force is removed, the soft cartridge  100  is restored back to its original shape, and expands as shown in FIG. 5. The expanded shape thereof is the endless track shape of a belt unit with its sides open. The photosensitive belt  10  is also received in the soft cartridge  100  in the same endless track shape as when the photosensitive belt  10  is installed around the belt unit within the image forming apparatus. To this end, a plurality of band members  110  and hooking pieces  120  are provided as restricting means and auxiliary restricting means. Since the band members  110  and the hooking pieces  120  can be rolled up when the soft cartridge  100  is rolled up, it is preferable that they are made of the same material as that of the soft cartridge  100 .  
         [0028]    The band member  110  is split into three branches at one end, and is integrally connected at the other end, as shown in FIGS. 5 and 6. In addition, a hexagonal engagement portion  113  is formed at the top end of the other end. The end portions of both outer branches  112  of the three branches are fixed to the upper inner wall surface of the soft cartridge  100 . The center branch  111  is passed through a slit  104  of the soft cartridge  1   00  and extends along the outer wall of the soft cartridge  100 . Reference numeral  111   a  denotes a cut portion formed so that the cut portion  111   a  can hook on the slit  104 , and the center branch  111  can be prevented from escaping from the slit  104 . Both the outer branches  112  are called fixed branches and the center branch  111  is called a movable branch. In addition, the engagement portion  113  at the other end of the band member  110  is elastically inserted into an engagement hole  102  formed at the side edge portion of the soft cartridge  100  positioned across the soft cartridge  100  from the slit  104  so that the band member  110  can extend across the upper inner wall of the soft cartridge  100 . That is, since the distance between two opposing angular points of the hexagonal engagement portion  113  is set to be longer than the width of the engagement hole  102 , the engagement portion  113  is elastically bent while inserted into the engagement hole  102 , and is expanded back to fix itself in place after passing through the engagement hole  102 .  
         [0029]    On the other hand, when the band member  110  is strongly pulled out, the engagement portion  113  is caused to escape from the engagement hole  102 . Reference numeral  103  denotes a stopper piece for preventing the engagement portion  113  from easily escaping from the engagement hole  102  due to even a small shock after the engagement portion  113  is inserted into the engagement hole  102 , and the free end of the stopper piece  103  is bent upward, as shown in FIG. 7. A reason why the free end of the stopper piece  103  is bent upward is to prevent the stopper piece  103  from hooking the photosensitive belt  10  within the soft cartridge  100  when the soft cartridge  100  is pulled out from the belt unit  300 .  
         [0030]    The photosensitive belt  10  is disposed between the band member  110  and the inner wall of the soft cartridge  100  configured as described above. That is, two upper portions of the photosensitive belt  10  are supported by the two band members  110  extending across the inner wall of the soft cartridge  100  so as not to be loosened in a downward direction (i.e., away from inner wall).  
         [0031]    The hooking pieces  120  are installed at the lower inner wall of the soft cartridge  100 . One end of each hooking piece  120  is fixed to the inner wall of the soft cartridge  100 , and the other end is a non-fixed end, i.e., a free end, and is bent to contact the inner wall of the soft cartridge  100 . Two edge portions of the lower portion of the photosensitive belt  10  are inserted, via the free ends of the hooking pieces  120 , and are supported between the hooking pieces  120  and the inner wall of the soft cartridge  100 .  
         [0032]    Consequently, the photosensitive belt  10  is supported by the band members  110  which are restricting means, and the hooking pieces  120  which are auxiliary restricting means, in the endless track shape within the soft cartridge  100 .  
         [0033]    In addition, reference numeral  130  denotes a high strength member made of a relatively high strength material such as stainless steel. Each high strength member  130  is inserted into a bag  101 , preferably provided at opposite side surfaces along a width of the soft cartridge  100 . Each high strength member is shaped to have the same curvature as that of the side surfaces of the soft cartridge  100 . These high strength members  130  assist the soft cartridge  100  in maintaining the endless track shape by causing the curvature of both the side surfaces of the soft cartridge  100  to be maintained. Preferably, the high strength members  130  are installed so that a user can carry the soft cartridge  100  while holding portions of the high strength members  130 , and so that the user can hold the portions of the high strength members  130  while inserting the soft cartridge  100  around the belt unit  300  to install the photosensitive belt  10 .  
         [0034]    In addition, reference numeral  105  denotes a projection to be detected by a sensor  301  (FIG. 8). The projection  105  is provided so that the sensor  301  provided at the belt unit can sense the projection  105  and inform the user of the completion of the insertion of the soft cartridge  100 , when the soft cartridge  100  is inserted into the image forming apparatus.  
         [0035]    As shown in FIG. 4, such a soft cartridge  100  is rolled up and stored in the hard cartridge  200  until the soft cartridge  100  is used while containing the received photosensitive belt  10  therein. As a result, since the soft cartridge  100  is stored in the cylindrical hard cartridge  200  in a rolled-up state, the space occupied by the hard cartridge  200  can be much smaller than that required when the photosensitive belt  10  is conventionally stored on a cartridge in the fully expanded volume of the endless track shape.  
         [0036]    When the photosensitive belt  10  is required to be installed, the soft cartridge  100  receiving the photosensitive belt  10  is pulled out from the hard cartridge  200  after removing a cap  210  of the hard cartridge  200 . Then, the soft cartridge  100  expands back as shown in FIG. 5.  
         [0037]    As shown in FIG. 8, a plurality of rollers including three main supporting rollers  311 ,  312  and  313  are installed between a front frame  310  and a rear frame  320  in a belt unit  300  around which the photosensitive belt  10  is to be installed. The photosensitive belt  10  circulates around the endless track while supported by the rollers. Reference numeral  314  denotes the shafts of the rollers besides the main rollers  311 ,  312 , and  313 , which support the lower portion of the photosensitive belt  10 , and the shafts  314  extend and project in front of the front frame  310 .  
         [0038]    In order to install the photosensitive belt  10 , first, an installation guide member  400  is installed at the front frame  310  of the belt unit  300 , as shown in FIG. 9. The installation guide member  400  has a connection hook  420  which is elastically fitted to a connection hole  302  (FIG. 8) of the front frame  310 , as shown in FIGS. 9 and 10, and has a sloping surface  410  which gradually enlarges in a direction from the outside of the image forming apparatus to the belt unit  300 . The sloping surface  410  is formed in consideration of possible drooping of the soft cartridge  100  on the open side since the soft cartridge  100  is flexible as described above. Therefore, although the soft cartridge  100  droops on the open side, the soft cartridge  100  is easily fitted to the belt unit  300  along the sloping surface  410 , and is gradually spread by the sloping surface  410  to restore its original endless track shape while pushed on around the belt unit  300 . Reference numeral  440  denotes holes for receiving the shafts  314  of the above rollers, and reference numeral  430  denotes a marking projection for guiding the position of completion of the pushing operation of the soft cartridge  100  around the belt unit  300 .  
         [0039]    After the installation guide member  400  as described above is installed at the front frame  310  of the belt unit  300 , the soft cartridge  100  taken out from the hard cartridge  200  is pushed on around the belt unit  300  as shown in FIG. 11. At this time, when the user holds both sides of the soft cartridge  100  at which the high strength members  130  are installed, and pushes the soft cartridge  100  on around the belt unit  300 , the open side of the soft cartridge  100  is gradually spread along the sloping surface  410  of the installation guide member  400 , and is fitted to the belt unit  300 . The soft cartridge  100  is pushed on until the rear edge of the soft cartridge  100  is aligned with the marking projection  430  formed on the installation guide member  400 . At this moment, the projection  105  (FIG. 5) is sensed by the sensor  301 , and the sensor  301  generates a signal for informing the user of the completion of the pushing operation of the soft cartridge  100 .  
         [0040]    When the pushing operation of the soft cartridge  100  is completed as shown in FIG. 12, the user holds the movable branches  111  of the two band members  110  and pulls the movable branches  111  in the direction of arrows. Then, the engagement portions  113  of the band members  110  are pulled out from the respective engagement holes  102 , and accordingly, the photosensitive belt  10  hung over and supported by the band members  110  is seated around the rollers including the main supporting rollers  311 ,  312 , and  313  of the belt unit  300 . The triangle symbols marked on the movable branches  111  are intended for guiding the position of pulling the band members  110 . When the band members  110  are pulled until the symbols reach the edge of the soft cartridge  100 , the engagement portions  113  are completely pulled out from the engagement holes  102 .  
         [0041]    In this state, when the soft cartridge  100  is again pulled out from the belt unit  300 , the photosensitive belt  10  remains around the belt unit  300  and only the soft cartridge  100  is pulled away from the belt unit  300 . Since the belt unit  300  is provided with belt stoppers  303 , the belt stoppers  303  interfere with the photosensitive belt  10  so that the photosensitive belt  10  can not be pulled out together with the soft cartridge  100  when the soft cartridge  100  is pulled out from the belt unit  300 .  
         [0042]    As described above, after the soft cartridge  100  is pulled out, the installation guide member  400  is removed, and the installation of the photosensitive belt  10  is completed when the roller  313  is moved in the direction of the arrow shown in FIG. 13, making the photosensitive belt  10  tightly tensioned.  
         [0043]    In addition, it is preferable that the thickness of the material of the soft cartridge  100  is set to be about 0.15˜0.25 mm. When the thickness is too thin, the endless track shape cannot be maintained and the soft cartridge  100  easily droops, and when the thickness is too thick, it is difficult to roll up the soft cartridge  100 . Therefore, to make the thickness be about 0.15˜0.25 mm is advantageous for storing the soft cartridge  100  and performing the installation operation of the photosensitive belt  10 .  
         [0044]    In addition, if light passes through the soft cartridge  100 , the photosensitive belt therein may be damaged. Therefore, it is preferable that the color of the soft cartridge  100  is an opaque color such as a black color.  
         [0045]    As described above, when the operation of replacing a photosensitive belt is performed by employing the photosensitive belt cartridge of an electrophotographic image forming apparatus and the photosensitive belt installation device according to the present invention, since the soft cartridge can be stored in the hard cartridge in a rolled-up state before the installation, and can be expanded when installed, the space required for storing the photosensitive belt can be considerably reduced. In addition, since the soft cartridge is simply pushed on around the belt unit and is simply pulled out from the belt unit by using the installation guide member when the photosensitive belt is installed, the replacing operation of the photosensitive belt can be performed in a very convenient and fast manner.  
         [0046]    It is contemplated that numerous modifications may be made to the present invention without departing from the spirit and scope of the invention as defined in the following claims. For example, the engagement portion may have shapes other than hexagonal (e.g., polygonal, circular, and/or having different interior and exterior shapes).