Patent Publication Number: US-7711295-B2

Title: Toner cartridge having control board mounted therein and electrophotographic image forming apparatus using the same

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
   This application claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2005-0055895, filed on Jun. 27, 2005, in the Korean Intellectual Property Office. This application is a continuation of U.S. application Ser. No. 12/216,020, filed on Jun. 27, 2008 now U.S. Pat. No. 7,570,903, which is a continuation of U.S. application Ser. No. 11/368,620, filed on Mar. 7, 2006 which issued as U.S. Pat. No. 7,395,016. All of the aforementioned applications are hereby incorporated by reference in their respective entireties. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a toner cartridge and an electrophotographic image forming apparatus. More particularly, the present invention relates to a toner cartridge having a control board mounted therein and an electrophotographic image forming apparatus using the same. 
   2. Description of the Related Art 
   In general, an image forming apparatus irradiates light onto a photosensitive medium charged to a uniform potential to form an electrostatic latent image corresponding to a desired image on the photosensitive medium, develops the electrostatic latent image using a toner to form a toner image, and transfers and fuses the toner image onto a sheet of paper, thereby forming the desired image. 
   A multi-color image forming apparatus generally requires yellow (Y), magenta (M), cyan (C), and black (K) toners. These color toners overlap each other to form a desired multi-color image. Accordingly, the multi-color image forming apparatus requires four developing cartridges for storing the respective color toners. 
   A multi-color image forming apparatus having four developing cartridges has a larger volume and a more complicated structure than a monochromic image forming apparatus for forming a single color image. 
   Furthermore, the developing cartridge has various components such as a developing roller for developing an electrostatic latent image as well as toner. When the toner is exhausted, the developing cartridge should be replaced with a new developing cartridge. 
   The life spans of the other components are longer than that of the toner. Accordingly, it is not economical to replace the developing cartridge with a new developing cartridge after the toner is exhausted, because the developing cartridge is replaced with a new developing cartridge even though the other components can still be used. 
   Accordingly, a method of separately supplying only a toner to use the developing cartridge until the life span of all components has been reached has been suggested. That is, the toner cartridge in which the toner is stored and the developing cartridge are separated, and, when the toner is exhausted, the toner cartridge is replaced with a new toner cartridge to supply the new toner. Thus, the developing cartridge is continuously used for the life span of the developing components. 
   This toner cartridge has a control board which can detect the life span of the toner. The toner board detects the depletion of toner stored in the toner cartridge and the other information regarding the toner cartridge and is generally attached to the outside of the toner cartridge. 
   The control board attached to the outside of the toner cartridge may be damaged by external impact due to, for example, a user&#39;s carelessness, and may be bumped against the other components when mounting or dismounting the toner cartridge. Also, the control board may be contaminated with foreign substances. 
   Accordingly, there is a need for an improved toner cartridge with a control board that is protected from external impacts, and an electrophotographic image forming apparatus using the same. 
   SUMMARY OF THE INVENTION 
   An aspect of the present invention is to address at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a toner cartridge in which a control board is mounted so that the control board can be protected from external impact and an electrophotographic image forming apparatus using the same. 
   According to an aspect of the present invention, a toner cartridge includes a toner tube having a mounting part on which a control board is mounted, a control board cover for covering the mounting part to mount the control board therein, and a sealing cover for sealing the toner tube. 
   In the exemplary embodiment, the control board cover may include an opening through which a contact part of the control board is exposed to the outside. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features, and advantages of certain embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a schematic diagram of an electrophotographic image forming apparatus having a developing cartridge using a conveying means according to an exemplary embodiment of the present invention; 
       FIG. 2  is a perspective view of the arrangement of toner supplying units of a plurality of developing cartridges shown in  FIG. 1 ; 
       FIG. 3  is an exploded cross-sectional view of a toner cartridge having a control board mounted therein according to an exemplary embodiment of the present invention; 
       FIG. 4  is a front view of the toner cartridge shown in  FIG. 3 ; and 
       FIG. 5  is a partial perspective view of the toner cartridge shown in  FIG. 3 . 
   

   Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. 
   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   The matters defined in the description such as a detailed construction and elements are provided to assist in a comprehensive understanding of the embodiments of the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
   Referring to  FIG. 1 , an image forming apparatus includes a photosensitive drum  10 , a plurality of developing cartridges  20 , a plurality of toner cartridges  30 , an intermediate transfer belt assembly  50  with an intermediate transfer belt  51 , a first transfer roller  54 , a second transfer roller  60 , and a fusing unit  70 . 
   The photosensitive drum  10  has a photoconductive layer formed on its outer circumferential surface. Instead of the photosensitive drum  10 , a photosensitive belt may be employed. A charging roller  11 , which is an example of a charger, is disposed adjacent to the outer circumferential surface of the photosensitive drum  10  to charge the photosensitive drum  10  to a uniform potential. A cleaning means  12  removes any toner that remains on the photosensitive drum  10  after transfer. 
   The charging roller  11  charges the photosensitive drum  10  while rotating in contact with or without contacting the outer circumferential surface of the photosensitive drum  10  to make the outer circumferential surface of the photosensitive drum  10  have a uniform potential. Instead of the charging roller  11 , a corona charger may be employed. 
   An exposure unit  140  irradiates light corresponding to image information onto the photosensitive drum  10  charged to the uniform potential to form an electrostatic latent image. The exposure unit  140  generally includes a laser scanning unit (LSU) using a laser diode as a light source. 
   The plurality of toner cartridges  30 Y,  30 M,  30 C, and  30 K contain yellow (Y), magenta (M), cyan (C), and black (K) toners, respectively. The plurality of developing cartridges  20 Y,  20 M,  20 C, and  20 K receive the respective color toners from the plurality of the toner cartridges  30 Y,  30 M,  30 C, and  30 K to develop the electrostatic latent image formed on the photosensitive drum  10 . 
   Each of the plurality of the developing cartridges  20  includes a developing roller  21  that is spaced from the photosensitive drum  10  by a developing gap. It is preferable that the development gap can be several tens or several hundreds of micron. 
   The image forming apparatus according to the exemplary embodiment of present invention is a multi-pass type image forming apparatus in which the plurality of the developing cartridges  20 Y,  20 M,  20 C, and  20 K sequentially operate to form an image. In this multi-pass type image forming apparatus, a developing bias may be applied to the developing roller  21 K of a selected developing cartridge  20 K while either no developing bias or a development preventing bias is applied to the developing rollers  21 Y,  21 M, and  21 C of the other developing cartridges  20 Y,  20 M, and  20 C. Alternatively, only the developing roller  21  of the selected developing cartridge  20 K may rotate and the developing rollers  21  of the other developing cartridges  20 Y,  20 M, and  20 C may not rotate. 
   As shown in  FIG. 2 , the plurality of the developing cartridges  20 Y,  20 M,  20 C, and  20 K are disposed in parallel in a travel direction of the photosensitive drum  10 . Toner supplying units  27  of the plurality of the developing cartridges  20 Y,  20 M,  20 C, and  20 K are offset from each other in a lengthwise direction so that the plurality of the toner cartridges  30 Y,  30 M,  30 C, and  30 K do not interfere with each other. With this arrangement, the height of the image forming apparatus can be minimized. 
   The plurality of the toner cartridges  30 Y,  30 M,  30 C, and  30 K may be disposed on the developing cartridges  20 Y,  20 M,  20 C, and  20 K without interfering with one another. Each toner cartridge includes a toner tube  31 , a control board cover  34 , and a sealing cover  35 , as shown in  FIGS. 3 and 4 . 
   One side of the toner tube  31  is opened and a toner storing part  32  for receiving a toner is provided in the toner tube  31 . The other side of the toner tube  31  is closed and a mounting part  33  for mounting a control board  40  is provided at the outside of the toner tube  31 . The control board  40  may be fixed to the mounting part  33 . 
   The control board cover  34  is coupled to the toner tube  31  while covering the mounting part  33  so that the control board  40  is mounted in the mounting part  33 . The control board cover  34  is fused to the toner tube  31  by applying heat to the coupled portion or bonded to the toner tube  31  by using an adhesive. Since the toner tube  31  and the control cover  34  are generally made of plastic, they are easily fused or bonded to each other. 
   The control board cover  34  further includes an opening  341  through which contact parts  41  of the control board  40  are exposed to the outside. Accordingly, when the control board  40  is mounted on the mounting part  33  and then the control board cover  34  is put on the mounting part  33 , the contact parts  41  are exposed to the outside through the opening  341 . 
   The sealing cover  35  blocks the toner storing part  32  from the outside. After the sealing cover  35  is inserted into one side (opened side) of the toner tube  31 , the sealing cover  35  is fused to the toner tube  31  by applying heat to the coupled portion or bonded to the toner tube  31  by using an adhesive. Since the sealing cover  35  is generally made of plastic, it is easily fused or bonded to the toner tube  31 . 
   It is preferable that the control board cover  34  and the sealing cover  35  are tightly integrally coupled to the toner tube  31 . 
   The toner cartridge  30  further includes an agitator  36  for agitating the toner (not shown) received in the toner storing part  32  and a driving unit  38  for driving the agitator  36 . 
   The driving unit  38  includes a driving shaft  381  and a driving gear  382  which is provided at one side of the driving shaft  381  and connected to an external power source to receive power. A fixing groove  383  into which a washer  37  for fixing the other side of the driving shaft  381  to the inside of the toner tube  31  can be inserted is formed at the other side of the driving shaft  381 . It is preferable that the driving gear  382  is a helical gear. 
   Since the teeth of helical gear are twisted at a predetermined angle with respect to the axis of the gear, axial thrust is generated. Further, hardly any vibration is generated because the gear contact area is wide. 
   The driving shaft  381  penetrates through the control board cover  34 , the control board  40 , and the toner tube  31 . The control board  40  and the toner tube  31  have penetrating holes  42  and  311  through which the driving shaft  381  penetrates, respectively. 
   A receiving groove  312  into which the washer  37  can be inserted is formed on the inside of the toner storing part  32 . As shown in  FIG. 1 , when the toner cartridge  30  is mounted on the developing cartridge  20  and receives power from an external power source in the state where the washer  37  is inserted into the fixing groove  383 , thrust is generated in the axial direction of the driving shaft  381 , and the washer  37  is tightly inserted into and closely adhered to the receiving groove  312 . Thus, the receiving groove  312  and the penetrating hole  311  are sealed so that the toner received in the storing part  32  is prevented from leaking to the outside and the control board  40  is prevented from being contaminated by the toner. This effect can be obtained by using the helical gear as the driving gear  382 . 
   In an exemplary embodiment, the opening  341  of the control board cover  34  and the driving unit  38  are provided at a same side of the toner tube  31 . That is, the opening  341  of the control board cover  34  can be provided at the side of the driving gear  382 , in order to conveniently mount the toner cartridge  30  on the developing cartridge  20 . If the opening  341  and the driving unit  38  are provided at different sides of the toner tube  31 , the control board  40  and the driving unit  38  are connected in different directions, respectively, thereby imposing limitations on the mounting arrangement. 
   As shown in  FIG. 5 , the toner cartridge  30  includes a toner outlet  313  through which the toner is introduced into the developing cartridge  20  after being mounted on the image forming apparatus, at a surface facing the developing cartridge  20 . The toner outlet  313  is opened or closed by a shutter (not shown). That is, when the toner cartridge  30  is mounted on the developing cartridge  20 , the toner outlet  313  is opened, and, when the toner cartridge  30  is separated from the developing cartridge  20 , the toner outlet  313  is closed to prevent toner from flowing out. 
   A method of assembling the toner cartridge  30  will now be described. 
   First, the control board  40  is mounted on the mounting part  33  of the toner tube  31 , and then the control board cover  34  is inserted into the toner tube  31  to mount the control board in the toner tube  31 . Then, the coupled portion of the control board cover  34  and the toner tube  31  are fused or bonded to be integrally coupled to each other. 
   After the driving unit  38  penetrates through the control board cover  34 , the control board  40 , and the toner tube  31 , the washer  37  is inserted into and fixed to the fixing groove  383 . 
   At this time, the agitator  36  may be fixed to the driving shaft  381  before or after the washer  37  is inserted into the fixing groove  383 . 
   Next, the sealing cover  35  is inserted into the opened side of the toner tube  31  and then the coupled portion is fused or bonded to be integrally coupled to each other. 
   To disassemble the toner cartridge  30 , the steps to assemble the toner cartridge  30  are reversed. 
   The intermediate transfer belt  51  is supported by supporting rollers  52  and  53  and travels at a linear travel speed equal to a linear rotating speed of the photosensitive drum  10 . A length of the intermediate transfer belt  51  should be the same or longer than a length of a sheet of paper P having a maximum size, which is used in the image forming apparatus. 
   The first transfer roller  54  faces the photosensitive drum  10  and a first transfer bias is applied to transfer the toner image formed on the photosensitive drum  10  onto the intermediate transfer belt  51 . The second transfer roller  60  faces the intermediate transfer belt  51 . While the toner image is being transferred from the photosensitive drum  10  onto the intermediate transfer belt  51 , the second transfer roller  60  is spaced apart from the intermediate transfer belt  51 , and when the toner image is completely transferred onto the intermediate transfer belt  51 , the second transfer roller  60  contacts the intermediate transfer belt  51  with a predetermined pressure. The second transfer roller  60  is applied with a second transfer bias for transferring the toner image onto the sheet. 
   The fusing unit  70  applies heat and pressure to the toner image transferred onto the sheet to fuse the toner image on the sheet. 
   As described above, in the toner cartridge having the control board mounted therein and the electrophotographic image forming apparatus using the same according to the present invention, the control board is provided in the toner cartridge and thus the toner cartridge can be prevented from being damaged due to the external impact and from malfunctioning due to contamination. 
   While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.