Patent Publication Number: US-2015063872-A1

Title: Image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to, and claims priority benefit of Korean Patent Application No. 10-2013-0104823, filed on Sep. 2, 2013, and Korean Patent Application No. 10-2013-0130976, filed on Oct. 31, 2013, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     The following description relates to an image forming apparatus, a toner container, and a method, and more particularly, to an image forming apparatus to which a toner container is applied. 
     2. Description of the Related Art 
     To perform printing on a paper sheet, a transfer method of scanning a laser beam onto an image receptor (for example, a photosensitive drum) may be applied to form an electrostatic latent image, developing the electrostatic latent image as a toner image, and transferring the toner image onto a printing sheet directly or by using a transfer belt. 
     In an image forming apparatus, such as a laser printer using this printing method, a toner supply unit that supplies toner to a main body of the image forming apparatus is generally installed in a consumable form to be replaceable. 
     To install the toner supply unit in the main body, a part of an external housing of the main body of the image forming apparatus may need to be opened. Therefore, it may be difficult to check whether the toner supply unit is installed without opening the external housing. Since opening and closing of the external housing may be required replacement of the toner supply unit may be inconvenient. 
     SUMMARY 
     Exemplary embodiments may address at least the above problems and/or disadvantages and other disadvantages not described above. However, the exemplary embodiments are not required to overcome the disadvantages described above, and an exemplary embodiment may not overcome any of the problems described above. 
     An exemplary embodiment provides an image forming apparatus that facilitates easily checking whether a toner supply unit is installed, and conveniently performing work associated with replacement of the toner supply unit. 
     According to an aspect of an exemplary embodiment, an image forming apparatus is provided including a main body, and at least one toner container configured to be installed in the main body. The toner container may have a bottle shape. The toner container may be installed in a toner container installing groove. The toner container installing groove may be formed to be concave from an upper housing part of the main body. 
     The toner container may be installed in the toner container installing groove so as to expose at least a portion thereof outside the main body. 
     The toner container installing groove may vertically extend from the upper housing part downwards. 
     The upper housing part of the main body may include a toner container installing part having the toner container installing groove. The toner container installing part may include a lower part configured to have at least one toner discharge hole, and a vertical extending part configured to vertically extend from the lower part toward the upper housing part of the main body. 
     The toner container may include a container body configured to include at least one toner discharge hole that is formed in the container body, and a shutter member configured to be installed in the container body so as to be arranged in a first position for closing the toner discharge hole or in a second position for opening the toner discharge hole. 
     The shutter member may slide between the first and second positions in the container body. 
     The toner container may include an elastic pressurizing member that elastically pressurizes the shutter member into the first position. A lower part of the toner container installing part may include a pressurizing protrusion that pressurizes the shutter member into the second position when installing the toner container. 
     The shutter member may include a shutter part configured to have a disc shape and close the toner discharge hole when the shutter member is arranged in the first position, a support part configured to protrude from an upper surface of the shutter part and support the elastic pressurizing member, and a pressurized part configured to protrude from a lower surface of the shutter part and pressurize the pressurizing protrusion when installing the toner container. 
     The container body may be installed in the toner container installing part to bilaterally rotate within a preset angle range. An arrangement of the shutter member may be changed from the first position into the second position by a forward rotation of the container body or may be changed from the second position into the first position by a backward rotation of the container body. 
     At least one toner discharge hole may be formed in a lower part of the container body. At least one shutter hole may be formed in the shutter member and may be arranged to correspond to the at least one toner discharge hole in the second position. 
     At least one fixing protrusion may be formed at the toner container installing part to fix the shutter member, and at least one fixing groove may be formed in a lower part of the shutter member so as to insert the fixing protrusion thereinto. 
     The fixing protrusion may be elastically supported upwards by an elastic support member that is formed in the toner container installing part. 
     A screw protrusion may be formed at the lower surface of the container body, and a screw hole may be formed in the shutter member to be screwed to the screw protrusion. 
     At least one rotation protrusion may be formed at a side part of the container body, and at least one rotation guide groove may be formed in an inner surface of the toner container installing part to guide a rotation of the rotation protrusion. 
     At least one vertical guide groove may be formed in an inner surface of the vertical extending part to guide the rotation protrusion from the upper housing part to the rotation guide groove when installing the toner container. 
     The image forming apparatus may include a single toner container. 
     A toner amount display unit may be installed in the upper housing unit of the main body to display a residual amount of toner in the toner container in an analog way and may be arranged parallel with the toner container. 
     According to an exemplary embodiment, a toner container for an image forming apparatus having a housing part is provided, the toner container including at least one toner discharge hole capable of being opened upon installing the toner container in the image forming apparatus, a shutter member for opening and closing the toner discharge hole, and a pressurizing protrusion part for pressurizing the toner container. 
     The toner container may be color-coded to identify a color of toner contained in the toner container. 
     According to an exemplary embodiment, a method for installing a toner container in an image forming apparatus is provided including inserting the toner container in the image forming apparatus, and rotating the toner container to open a toner discharge hole. 
     The method may include rotating the toner container pressurizing a shutter member of the toner container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an image forming apparatus according to an exemplary embodiment; 
         FIG. 2  is a perspective view illustrating an exemplary image forming apparatus from which a toner container is separated; 
         FIG. 3  is an exemplary cross-sectional view taken along line I-I of  FIG. 1 ; 
         FIG. 4  is an exploded perspective view of an exemplary toner container installed in an image forming apparatus; 
         FIG. 5  is a perspective view of an exemplary container installing part of an image forming apparatus; 
         FIGS. 6A and 6B  are views illustrating a process of inserting a toner container into a toner container installing part, according to an exemplary embodiment; 
         FIG. 7  is a perspective view of an exemplary alternative toner container that is installable in a main body of an image forming apparatus; 
         FIG. 8  is an exploded perspective view of an exemplary alternative toner container; 
         FIG. 9  is a plan view illustrating an exemplary part around a toner container installing groove of a main body of an image forming apparatus in which the toner container is installed; 
         FIG. 10  is a partial cross-sectional view of an image forming apparatus in which an exemplary toner container is installed; 
         FIG. 11  is a partial cross-sectional view illustrating an alternative arrangement of an exemplary shutter member; 
         FIG. 12A  is a cross-sectional view taken along line II-II of  FIG. 10  to illustrate an exemplary completed state of an operation of inserting a toner container in a process of installing the toner container in a main body of an image forming apparatus; 
         FIG. 12B  is a cross-sectional view taken along line II-II of  FIG. 10  to illustrate a completed state of an operation of rotating a toner container in a process of installing the toner container in the main body of a image forming apparatus; 
         FIG. 13  is a cross-sectional view illustrating the toner container of  FIG. 7 , according to another exemplary embodiment of the present general inventive concept; 
         FIG. 14  is a perspective view of an image forming apparatus according to an exemplary embodiment; 
         FIG. 15  is a perspective view illustrating an exemplary image forming apparatus o from which toner containers are separated; 
         FIG. 16A  is an exemplary cross-sectional view taken along line III-Ill of  FIG. 14 ; and 
         FIG. 16B  is an exemplary cross-sectional view taken along line IV-IV of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments are described in greater detail with reference to the accompanying drawings. 
     In the following description, the same drawing reference numerals are used for the same elements in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the exemplary embodiments. Thus, it is apparent that the exemplary embodiments can be carried out without those specifically defined matters. Also, well-known functions or constructions are not described in detail because they would obscure the description of exemplary embodiments with unnecessary detail. 
       FIG. 1  is a perspective view of an image forming apparatus  1  according to an exemplary embodiment.  FIG. 2  is an exemplary perspective view of an image forming apparatus  1  from which a toner container may be separated.  FIG. 3  is an exemplary cross-sectional view taken along line I-I of  FIG. 1 . 
     As illustrated in  FIGS. 1 through 3 , the image forming apparatus  1  may be a monochrome laser printer having a small size and includes a main body  100 . A toner container  200  may be detachably installed in, or to, the main body  200 . 
     The main body  100  includes an external housing  110  that houses a plurality of internal parts and forms an external appearance of the image forming apparatus  1 . The external housing  110  lower and upper housing parts  111  and  114  may face each other to form upper and lower surfaces of the image forming apparatus  1 , front and back housing parts  112  and  113  may face each other to form front and back surfaces of the image forming apparatus  1 , and right and left housing parts  115  and  116  may face each other to form right and left surfaces of the image forming apparatus  1 . The main body  100  of the image forming apparatus  1  may have, for example, a simple rectangular parallelepiped external appearance. 
     As illustrated in  FIG. 1 , an acoustic emission part  118  having acoustic emission holes may be formed in the front housing part  112 . The main body  100  may include a speaker unit (not illustrated) that provides a sound such as a notification sound, music, or the like through the acoustic emission part  118 . As illustrated in  FIG. 1 , the right housing part  115  includes a universal serial bus (USB) port  119 . The USB port  119  may be included in the left housing part  116  and/or the back housing part  113 . If an external apparatus such as a smartphone, a personal computer (PC), or the like, is connected to the USB port  119  through an USB cable, the image forming apparatus  1  may operate as a printer that outputs image data provided by the external apparatus connected to the USB port  119  and/or operate as a speaker that outputs acoustic data provided by the external apparatus. 
     As illustrated in  FIG. 3 , a paper inserting door  113   a  for insertion of a paper sheet into the main body  100  may be included in the back housing part  113 . The paper inserting door  113   a  may be pivotably combined with the back housing par  113  with a hinge  113   b . When performing a printing job, a user opens the paper inserting door  113   a  to lean the paper inserting door  113   a  against the back housing part  113  in order to supply paper sheets into the main body  100 . 
     As illustrated in  FIG. 3 , the front housing part  112  may be pivotably combined with the lower housing part  111  through a hinge  112   a . Therefore, when performing the printing job, the front housing part  112  may be opened by the user, for example, to be parallel with the lower housing part  111 . Therefore, paper sheets on which the printing job has been completed may be sequentially loaded on the front housing part  112  that is opened to be parallel with the lower housing part  111 . 
     As illustrated in  FIG. 2 , a toner amount display unit  102  may be installed on the upper housing part  114  to display a residual amount of toner in the toner container  200 , for example, with an analog display. The toner amount display unit  102  may be parallel with the toner container  100  and a distance from the toner container  200 . According to an exemplary embodiment, display scales of the toner amount display unit  102  may be arranged vertically. Alternatively, the display scales of the toner amount display unit  102  may be arranged in a circular shape, e.g., similar to a speedometer display in a car. The user may view the toner display unit  102  to easily check the residual amount of toner in the toner container  200  without, for example, a computer monitor connected to the image forming apparatus  1 . 
     An exemplary toner container  200  is illustrated in  FIGS. 1 and 2 . The toner container may include feeding entrances formed on the top and housing spaces connected to the feeding entrances, and may be a bottle shape. The toner container  200  may have a circular cross-section according to an exemplary embodiment. Alternatively, the toner container  200  may have various cross-section shapes such as a elliptical cross-section, a rectangular cross-section, etc. 
     The toner container  200  contains, for example, monochrome toner (for example, black toner). A toner container installing groove  101  may be formed in the main body  100 , for example, to be concave from the upper housing part  114 . The toner container  200  may be installed in the toner container installing groove  101  to supply toner contained in the toner container  200  into the main body  100 . 
     Alternatively, the toner container installing groove  101  may be formed in a side of the main body  100  such as the left housing part  115  or the right housing part  116 . According to an exemplary embodiment, the toner container installing groove  101  may be formed in the upper housing part  114  of the main body  100  to allow the user to easily install the toner container  200  into the toner container installing groove  101 . 
     The toner container installing groove  101  vertically extends from the upper housing  114  downwards. Therefore, the toner container  200  installed in the toner container installing groove  101  is vertically arranged, and thus the toner contained in the toner container  200  may be smoothly discharged outside the toner container  200  with assistance of gravity. Since the toner container installing groove  101  may not be covered with an external casing  110  and be exposed to the outside, additional work for opening the external casing  110  is not needed when replacing the toner container  200 . Therefore, work related to replacement work of the toner container  200  may be easily performed. 
     Only one toner container  200  is illustrated in  FIGS. 1 and 2 , but another, for example, longer toner container (not illustrated) may be further used. In other words, a plurality of toner containers having same or different capacities may be installed in the main body  100 . Since the toner container  200  may be installed in the main body  100  to expose at least an upper part thereof to the outside, the user may check which type of toner container is installed in the main body  100  without viewing an interior of the main body  100 . 
     As illustrated in  FIG. 3 , the main body  110  houses parts such as a developer unit  120 , a pickup unit  141 , one or more transfer units  142 , a transfer roller  143 , a fixing unit  144 , a paper discharge unit  145 , a exposure unit  146 , etc. The developer unit  120  includes a developer unit casing  121 . A photosensitive drum  122 , a developer roller  123 , and a supply roller  124  may be housed in the developer unit casing  121 . 
     A printing process of the image forming apparatus  1  according to a paper path P is described. When a printing job starts, an electrostatic latent image reflecting printing data may be formed on the photosensitive drum  122  through a laser provided by the exposure unit  146  and developed as a toner image by the developer roller  124 . A printing paper sheet may be picked up by the pickup unit  141  and passes through the photosensitive drum  122  and the transfer roller  143  so as to transfer the toner image formed on the photosensitive drum  122  onto the printing paper sheet. Thereafter, the printing paper sheet undergoes an image fixing process performed by the fixing unit  144  and is discharged outside the main body  100  by the paper discharge unit  145 . 
     As illustrated in  FIG. 3 , the toner container installing part  150  having the toner container installing groove  101 , illustrated in  FIG. 2 , may be installed in the upper housing part  114  of the main body  100 . The toner container installing part  150  vertically extends from the upper housing part  144  into the main body  100  and may be connected to the developer unit casing  121 . Therefore, when the toner container  200  is completely installed in the toner container installing part  150 , toner discharged from the toner container  200  may be supplied into the developer unit  120  through the toner container installing part  150 . According to an exemplary embodiment, the toner container installing part  150  may form a part of the upper housing part  114 . Alternatively, the toner container installing part  150  may form a part of the developer unit casing  121 . 
     The toner container  200  and the toner container installing part  150  are described in detail with reference to  FIGS. 4 ,  5 ,  6 A, and  6 B. 
       FIG. 4  is an exploded perspective view of a toner container  200  installed in the image forming apparatus  1 .  FIG. 5  is a perspective view of a toner container installing part  150  installed in the image forming apparatus  1 .  FIGS. 6A and 6B  are views illustrating a process of installing the toner container  200  in the toner container installing part  150 . 
     As illustrated in  FIGS. 4 and 6A , the toner container  200  includes a container body  210 , a cap member  220 , a shutter member  230 , and a elastic pressurizing unit  240 . 
     The container body  210  has an approximately cylindrical shape and includes a toner containing space  215 . A toner discharge hole  211   a  is formed in a lower part  211  of the container body  210 . A screw thread  213 , for example female screw thread may be formed in a particular width on a side part  212  of the container body  210 . 
     The cap member  220  may be combined with an upper part of the container body  210  to prevent toner contained in the toner container  200  from being discharged up the toner container  200 . The cap member  220  includes a cap part  221  that closes the upper part of the container body  210  and a shutter guide protrusion  222  that protrudes from a lower surface of the cap part  221 . 
     The shutter member  230  includes a shutter part  231 , which may have a disc shape, an elastic member support part  232  that protrudes from an upper surface of the shutter part  231 , and a pressurized part  233  that protrudes from a lower surface of the shutter part  231 . 
     The shutter part  231  opens and closes the toner discharge hole  211   a  that is formed in the container body  210 . As illustrated in  FIG. 6A , a diameter of the shutter part  231  is smaller than an internal diameter of the container body  210 . Therefore, a path C that is used to move toner is formed between the shutter part  231  and the container body  210 . 
     The elastic member support part  231  is inserted into the elastic pressurizing member  240  to support the elastic pressurizing member  240  so that the elastic pressurizing member  240  maintains a position thereof between the cap part  221  and the shutter part  231 . A shutter guide hole  234  into which the shutter guide protrusion  222  of the cap member  220  is inserted may be formed in the elastic member support part  232 . The shutter guide protrusion  222  may be inserted into the shutter guide hole  234  to accurately perform upward and downward movements of the shutter member  230 . 
     The pressurized part  233  may be pressurized by a pressurizing protrusion  154  of the toner container installing part  150  of  FIG. 6A  when the toner container  200  is installed in the toner container installing part  150 . 
     The elastic pressurizing member  240  elastically pressurizes the shutter member  230  downwards. According to an exemplary embodiment, the elastic pressurizing member  240  is included as a coil spring that is disposed between the cap part  221  and the shutter member  230  of the cap member  220 . The elastic pressurizing member  240  may be supported by the elastic member support part  232  of the shutter member  230 . 
     As illustrated in  FIGS. 5 and 6A , the toner container installing part  150  includes a lower part  151  in which a plurality of toner discharge holes  153  may be formed and a vertical extending part  152  that vertically extends toward the upper housing part  114  of the main body  100  of the image forming apparatus  1 . 
     According to an exemplary embodiment, a plurality of toner discharge holes  153 , e.g., four toner discharge holes may be formed in the lower part  151 . The number of toner discharge holes  153  may be variously changed according to exemplary embodiments. The pressurizing protrusion  154  may be formed on an inner surface of the lower part  151 . When the toner container  200  is installed in the main body  100 , the shutter member  230  is pressurized upwards by the pressurizing protrusion  154  to open the toner discharge hole  211  of the toner container  200 . A male screw thread  155  corresponding to the female screw thread  213  is formed in a particular width on an inner surface of the vertical extending part  152 . 
     An exemplary process of installing the toner container  200  includes a first operation of inserting the toner container  200  into the toner container installing part  150  of the main body  100 , and a second operation of rotating the toner container  200  to open the toner discharge hole  211   a.    
       FIG. 6A  illustrates the toner container  200  and the toner container installing part  150  after the first operation (the toner inserting operation) is completed.  FIG. 6B  illustrates the toner container  200  and the toner container installing part  150  after the second operation (the toner container rotating operation) is completed. 
     As illustrated in  FIG. 6A , after the first operation (the toner container inserting operation) is performed, the shutter member  230  maintains a first position (a closed position) for closing the toner discharge hole  211   a , by an elastic force provided by the elastic pressurizing member  240 . The pressurizing protrusion  154  of the toner container installing part  150  does not contact the shutter member  230 . After the first operation (the toner container inserting operation) is performed, the toner discharge hole  221   a  is kept closed, and thus toner is not discharged from the toner container  200 . 
     As illustrated in  FIG. 6B , as the toner container  220  is rotated in a first direction (in a forward direction) in the second operation (the toner container rotating operation), the female screw thread  213  of the toner container  200  interacts with the male screw thread  155  of the toner container installing part  150  to position the toner container  200  a little more downwards. In the second operation, the shutter member  230  is pressurized by the pressurizing protrusion  154  of the toner container installing part  150  to be disposed in a second position (an opened position) for opening the toner discharge hole  211   a  of the container body  210 . Therefore, when the second operation (the toner container rotating operation) is completed, the toner discharge hole  211   a  of the toner container  200  is kept open, for example, as illustrated in  FIG. 6B . As a result, the toner contained in the toner container  200  may be supplied into the developer unit  120  through the toner discharge hole  211   a  of the toner container  200  and the toner discharge hole  153  of the toner container installing part  150 . 
     A process of separating the toner container  200  from the main body  100  may be performed directly opposite to the process of installing the toner container  200 . The toner container  200  may be rotated in a second direction (in a backward direction) to release an interaction between the screw threads  213  and  155  and pressurization of the pressurizing protrusion  154  onto the shutter member  230 . As illustrated in  FIG. 6A , since the pressurizing of the pressurizing protrusion  154  is released, the shutter member  230  returns into a first position in which the toner discharge hole  211   a  is closed by an elastic force of the elastic pressurizing member  240 . The toner container  200  may be removed from the toner container installing part  150  to complete the process of separating the toner container  200 . 
     The toner discharge hole  211   a  is closed by the shutter member  230 , and the toner container  200  may be separated from the toner container installing part  150 . Therefore, when performing work related to a replacement of the toner container  200 , the main body  100  and/or the user may be prevented from being soiled by residual toner in the toner container  200 . 
     An alternative toner container  300  may be installed in the main body  100 . The stoner container  300  is described with reference to  FIGS. 7 through 11 ,  12 A, and  12 B. 
       FIGS. 7 through 11  are first referred to. 
       FIG. 7  is a perspective view of the alternative toner container  300  that may be installed in the main body  100  of an image forming apparatus  1 .  FIG. 8  is an exemplary exploded perspective view of the toner container  300  of  FIG. 7 .  FIG. 9  is an exemplary plan view illustrating a part around a toner container installing groove of the main body  100  of the image forming apparatus  1  in which the toner container  300  of  FIG. 7  is installed.  FIG. 10  is an exemplary cross-sectional view of the image forming apparatus  1  in which the toner container  300  of  FIG. 7  is installed.  FIG. 11  is an exemplary cross-sectional view illustrating an alternative arrangement of a shutter member  330 . 
     The toner container  300  includes a container body  310  that has a cylindrical shape and includes a toner containing space  317 , a cap member  320  that may be combined with an upper end of the container body  310 , and a shutter member  330  that may be combined with a lower part  311  of the container body  310 . 
     The container body  310  includes a lower surface  311  that has a disc shape and a side part  312  that vertically extends from an edge of the lower surface  311  upwards. A screw protrusion  316  may be formed in a center of the lower surface  311  to protrude upwards. First and second toner discharge holes  313   a  and  313   b  and first and second fixed protrusion through-holes  314   a  and  314   b  may be formed in the lower surface  311 . First and second rotation protrusions  315   a  and  315   b  may be formed at an uppermost end of the side part  312 . According to an exemplary embodiment, two rotation protrusions  315   a  and  315   b  are included. Alternatively, according to exemplary embodiments, the number of rotation protrusions may be changed, for example, to one, three, or the like. 
     As illustrated in  FIGS. 9 and 10 , first and second rotation guide grooves  156   a  and  156   b  that guide rotations of the first and second rotation protrusions  315   a  and  315   b  may be formed on an inner surface of the vertical extending part  152  of the toner container installing part  150 . First and second vertical guide grooves  157   a  and  157   b  may be vertically formed on the inner surface of the vertical extending part  152  to guide the first and second rotation protrusions  315   a  and  315   b  to the first and second rotation guide grooves  156   a  and  156   b  when installing the toner container  300 . In consideration of shapes of the first and second rotation guide grooves  156   a  and  156   b  illustrated in  FIG. 9 , rotation angle ranges of the first and second rotation protrusions  315   a  and  315   b  may be, for example, each 90°. 
     The cap member  320  may be combined with an upper end of the container body  310  to prevent toner contained in the toner container from being discharged upwards. 
     The shutter member  330  opens and closes the toner discharge holes  313   a  and  313   b  of the container body  310 . Therefore, first and second shutter holes  331   a  and  331   b  that open and close the first and second discharge holes  313   a  and  313   b  may be formed in the shutter member  330 . A screw hole  333 , as illustrated in  FIG. 8 , for example, that interacts with the screw protrusion  316  of the container body  310  may be formed in a center of the shutter member  330 . Fixing grooves  332   a  and  332   b , for example, a pair of fixing grooves, may be formed in a lower surface of the shutter member  330 . Fixing protrusions  158   a  and  158   b , for example, a pair of fixing protrusions, (as illustrated, for example, in  FIG. 10 ) that are elastically supported by elastic support parts  159   a  and  159   b , for example, a pair of elastic support parts, may be installed at the lower part  151  of the toner container installing part  150 . When installing the toner container  300 , the fixing protrusions  158   a  and  158   b  may be inserted into the fixing grooves  332   a  and  332   b  of the shutter member  330  to fix the shutter member  300  so that the shutter member  330  is not rotated. In the illustrated exemplary embodiment, the number of fixing protrusions and the number of fixing grooves are respectively two, but the number may be changed, for example, to one, three, or the like. 
     The shutter member  330  may be screwed to the screw protrusion  316  of the container body  310  through the screw hole  333  to be installed on the lower surface  311  of the container body  310 . Since the shutter member  330  may be screwed to the container body  310  by a screwing method, positions of the fixing grooves  332   a  and  332   b  of the shutter member  330  may be set to accurately correspond to positions of the fixing protrusions  158   a  and  158   b  of the toner container installing part  150  at a time when the shutter member  330  is completely installed. Therefore, when the toner container  300  is installed in the toner container installing part  150 , the fixing protrusions  158   a  and  158   b  may be accurately inserted into the fixing grooves  332   a  and  332   b  of the shutter member  330 , for example, as illustrated in  FIG. 10 . 
     If the screw hole  333  and the screw protrusion  316  are replaced with a non-threaded hole and protrusion, the fixing grooves  332   a  and  332   b  of the shutter member  330  may be arranged in arbitrary positions and not in fixed positions. Therefore, when installing the toner container  300 , it may be difficult to accurately insert the fixing protrusions  158   a  and  158   b  into the fixing grooves  332   a  and  332   b  of the shutter member  330 . 
     As illustrated in  FIG. 10 , the screw protrusion  316  may be formed on the inner surface of the lower surface  311  of the container body  310 . The shutter member  330  may be arranged in the container body  310 . Alternatively, as illustrated in  FIG. 11 , the screw protrusion  316  may be formed on an outer surface of the lower surface  311  of the container body  310 . In this case, the shutter member  330  may be arranged outside the container body  310 . The fixing protrusion through-holes  314   a  and  314   b  do not need to be formed in the lower surface  311  of the container body  310 . 
       FIGS. 12A and 12B  are described. 
     Installing of the toner container  300  may be performed by a first operation of inserting the toner container  300  into the toner container installing part  150  of the main body  100 , and a second operation of rotating the toner container  300  to open the toner discharge holes  331   a  and  331   b.    
       FIGS. 12A and 12B  are cross-sectional views taken along line II-II of  FIG. 10 .  FIG. 12A  illustrates a completed state of a toner container inserting operation (the first operation) in a process of installing the toner container  300  of  FIG. 7 .  FIG. 12B  illustrates a completed state of a toner container rotating operation (the second operation) in the process of installing the toner container  300  of  FIG. 7 . 
     As illustrated in  FIG. 12A , if the toner container inserting operation (the first operation) is completed, the first and second rotation protrusions  315   a  and  315   b  of the container body  310  are arranged in the first and second rotation guide grooves  156   a  and  156   b  of the toner container installing part  150 . The fixing protrusions  158   a  and  158   b  of the toner container installing part  150  are inserted into the fixing grooves  332   a  and  332   b  (as illustrated, for example, in  FIG. 8 ) of the shutter member  330  through the fixing protrusion through-holes  314   a  and  314   b  of the container body  310  to prevent the shutter member  330  from being rotated. The toner discharge holes  313   a  and  313   b  formed in the container body  310  are kept closed by the shutter member  330 . 
     As illustrated in  FIG. 12B , the toner container  310  may be 90° rotated, for example, in a counter-clockwise direction (in direction R1) in the toner container rotating operation (the second operation). If the second operation is completed, the first and second toner discharge holes  313   a  and  313   b  of the container body  310  are arranged in positions corresponding to positions of the first and second shutter holes  331   a  and  331   b  of the shutter member  330 . Accordingly, the first and second toner discharge holes  313   a  and  313   b  of the container body  310  are opened by the shutter member  330 . Therefore, after the second operation is completed, the toner contained in the toner container  300  may be discharged from the toner container  300  to be supplied into the developer unit  120 . 
     Separating the toner container  200  from the main body  100  may be performed in an opposite manner to the work for installing the toner container  300 . The toner container  300  may be rotated, for example, 90° in a clockwise direction, opposite to direction R1 illustrated in  FIG. 12B  to close the toner discharge holes  313   a  and  313   b  by the shutter member  330 . Thereafter, the toner container  300  may be taken out of the toner container installing part  150  to complete the work for separating the toner container  300 . 
     After the toner container holes  313   a  and  313   b  are closed by the shutter member  330 , the toner container  300  may be separated from the toner container installing part  150 . Therefore, when performing a replacement of the toner container  300 , the main body  100  and/or the user may be prevented from being soiled by the residual toner in the toner container  300 . 
       FIG. 13  is a cross-sectional view illustrating the toner container  300  of  FIG. 7 , according to an exemplary embodiment. 
     As illustrated in  FIG. 13 , a female screw thread  315 ′ may be formed at the toner container  300 , and a male screw thread  156 ′ corresponding to the female screw thread  156 ′ may be formed at the toner container installing part  150 . Therefore, when opening and closing the toner discharge holes  313   a  and  313   b , rotation of the toner container  300  in the toner container installing part  150  may be achieved. According to the exemplary embodiment, the rotation protrusions  315   a  and  315   b  (as illustrated, for example, in  FIG. 8 ), the rotation guide grooves  156   a  and  156   b , and the vertical guide grooves  157   a  and  157   b  are not needed. 
       FIG. 14  is a perspective view of an image forming apparatus  2  according to an exemplary embodiment.  FIG. 15  is an exemplary perspective view of the image forming apparatus  2  of  FIG. 14  from which toner containers are separated. 
     As illustrated in  FIGS. 14 and 15 , the image forming apparatus  2  according to an exemplary embodiment is a two-color laser printer having a relatively small size and includes a main body  500  and two toner containers  600 A and  600 B that are detachably installed in the main body  500 . 
     The main body  500  includes an external housing  510  that houses a plurality of internal parts to form an external appearance of the image forming apparatus  2 . The external housing  510  includes lower and upper housing parts  511  and  514  that face each other to form lower and upper surfaces of the image forming apparatus  2 , front and back housing parts  512  and  513  that face each other to form front and back surfaces of the image forming apparatus  2 , and right and left housing parts  515  and  516  that face each other to form right and left surfaces of the image forming apparatus  2 . The main body  500  has an approximately simple rectangular parallelepiped appearance formed by the external housing  510 . 
     A paper discharge hole  512   a  that discharges a printed paper sheet may be formed in an upper end of the front housing part  512 . A front end of a paper tray unit  530  is exposed in a lower end of the front housing part  512 . A user may pull the paper tray unit  530  and supply paper sheets into the paper tray unit  530 . 
     The upper housing part  514  includes a front area  514   a  that is arranged in front and a back area  514   b  that is arranged at the back. The front and back areas  514   a  and  514   b  may have a step difference so that the back area  514   b  is arranged slightly deeper than the front area  514   a . Two toner container installing grooves  501 A and  501 B are formed in the back area  514   b  to be concave downwards. The external housing  510  includes a cover member  518  that may be formed of a transparent or semi-transparent material to open and close the back area  514   b.    
     The two toner containers  600 A and  600 B may have cylindrical or bottle shapes. The two toner containers  600 A and  600 B may be respectively installed in the first and second toner container installing grooves  501 A and  501 B formed in the upper housing part  514 . Therefore, toners contained in the toner containers  600 A and  600 B may be supplied in to the main body  500 . As illustrated in  FIG. 15 , the first and second toner container installing grooves  501 A and  501 B are arranged in parallel and distanced from each other. Therefore, the first and second toner containers  600 A and  600 B installed in the first and second toner container installing grooves  501 A and  501 B are arranged in parallel and distanced from each other. 
     Alternatively, the toner container installing grooves  501 A and  501 B may be formed in a side part of the main body  500  such as the left housing part  515  or the right housing part  516 . However, the toner container installing grooves  501 A and  501 B may be formed in the upper housing part  514  of the main body  500  according to an exemplary embodiment to allow the user to easily install the toner containers  600 A and  600 B in the toner container installing grooves  501 A and  501 B. 
     The toner container installing grooves  501 A and  501 B vertically extend from the upper housing part  514  downwards. Therefore, the toner containers  600 A and  600 B installed in the toner container installing grooves  501 A and  501 B are also vertically arranged to smoothly discharge the toners contained in the toner containers  600 A and  600 B outside the toner containers  600 A and  600 B with assistance of gravity. 
     Since the toner container installing grooves  501 A and  501 B are exposed to the outside only by opening of the cover member  518 , accesses to the toner containers  600 A and  600 B may be easy so as to conveniently perform work for installing and separating the toner containers  600 A and  600 B. 
     The toner containers  600 A and  600 B are long enough to expose at least portions thereof outside the toner container installing grooves  501 A and  501 B when the toner containers  600 A and  600 B are installed in the toner container installing grooves  501 A and  501 B. A part of a toner container, e.g., upper ends (for example, cap parts) of the toner containers  600 A and  600 B may have the same colors as those of toner contained therein. Therefore, the user may easily check types of toner containers installed in the image forming apparatus  2 . 
     The two toner containers  600 A and  600 B may contain different colors of toners. According to an exemplary embodiment, the first toner container  600 A contains a black color of toner, and the second toner container  600 B contains a highlight color of toner different from the black color of toner. For example, the second toner container  600 B may contain a red color of toner used for highlighting. However, an exemplary embodiment is not limited thereto, and the second toner container  600 B may contain a different color of toner (for example, blue color toner, green color toner, yellow color toner, or the like) that may be used for highlighting. 
     A basic color of toner, e.g., a black color of toner, and a red color of toner used for highlighting may be provided by the two toner containers  600 A and  600 B. Therefore, monochrome printing and monochrome printing to which highlighting is added may be performed by the image forming apparatus  2 . 
     Each of the toner containers  600 A and  600 B may have a structure such as one of the first type of toner container  200  of  FIG. 2  and the second type of toner container  300  of  FIG. 7 . Therefore, similar to the toner containers  200  and  300 , when performing a replacement work for the toner containers  600 A and  600 B, the main body  500  or the user may be prevented from being soiled by residual toners in the toner containers  600 A and  600 B. 
       FIG. 16A  is a cross-sectional view taken along line III-Ill of  FIG. 14 .  FIG. 16B  is a cross-sectional view taken along line IV-IV of  FIG. 14 . 
     As illustrated in  FIGS. 16A and 16B , the main body  500  may house parts such as first and second developer units  520 A and  520 B, a pickup unit  541 , a plurality of transfer units  542   a ,  542   b ,  542   c , first and second primary transfer rollers  543 A and  543 B, a secondary transfer roller  590 , a transfer belt  570 , a fixing unit  544 , a paper discharge unit  545 , first and second exposure units  546 A and  546 B, etc. 
     The first developer unit  520 A is a developer unit corresponding to the first toner container  600 A and includes a developer unit casing  521 A, and a photosensitive drum  522 A, a developer roller  523 A, and a supply roller  524 A that are housed in the developer unit casing  521 A. The second developer unit  520 B is a developer unit corresponding to the second toner container  600 B and includes a developer unit casing  521 B, and a photosensitive drum  522 B, a developer roller  523 B, and a supply roller  524 B that are housed in the developer unit case  521 B. The transfer belt  570  is rotatably supported by a driver roller  581  and an idle roller  582 . 
     Parts of the image forming apparatus  2  are disclosed. 
     A printing process performed by the image forming apparatus  2  according to a paper path P is disclosed. If a printing job starts, electrostatic latent images reflecting image data may be formed on the photosensitive drums  522 A and  522 B by laser beams provided by the exposure units  546 A and  546 B. The electrostatic latent images are converted into toner images by the developer rollers  523 A and  523 B and transferred to the transfer belt  570 . A printing paper sheet may be picked up by the pickup unit  541  and passes between the idle roller  582  and the secondary transfer roller  590  so as to secondarily transfer the toner images transferred to the transfer belt  570  onto the printing paper sheet. Thereafter, the printing paper sheet undergoes an image fixing process through the fixing unit  544  and may be discharged outside the main body  500  through the paper discharge hole  512   a.    
     One or more toner container installing parts, e.g., two toner container installing parts  550 A and  550 B may be formed in the upper housing part  514  of the main body  500 . 
     As illustrated in  FIG. 16A , the first toner container installing part  550 A has the first toner container installing groove  501 A (as illustrated in  FIG. 15 ) and vertically extends from the upper housing  514  into the main body  500 . The first toner container installing part  550 A may be connected to the developer unit casing  521 A of the first developer unit  520 A. Therefore, if the first toner container  600 A is completely installed in the first toner container installing part  550 A, a black color of toner contained in the first toner container  500 A may be supplied into the first developer unit  520 A through the first toner container installing part  550 A. 
     As illustrated in  FIG. 16B , the second toner container installing part  550 B has the second toner container installing groove  501 B (as illustrated in  FIG. 15 ) and vertically extends from the upper housing  514  into the main body  500 . The second toner installing part  550 B may be connected to the developer unit casing  521 B of the second developer unit  520 B. There, if the second toner container  600 B is completely installed in the second toner container installing part  550 B, a highlight color of toner contained in the second toner container  600 B may be supplied into the second developer  520 B through the second toner container installing part  550 B. 
     According to an exemplary embodiment, the toner container installing parts  550 A and  550 B may form a part of the upper housing part  514 . Alternatively, the toner container installing parts  550 A and  550 B may form a part of the developer unit casings  521 A and  521 B corresponding to the toner container installing parts  550 A and  550 B. 
     The foregoing exemplary embodiments and advantages are merely exemplary and are not to be construed as limiting. The present disclosure can be applied to other types of apparatuses. The description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and alternatives, modifications, and variations will be apparent to those of ordinary skill in the art.