Abstract:
A developing device includes: a housing that has a developer containing part and an opening, the developer containing part containing a developer, and the opening allowing the developer to flow through; a sheet member that is provided in the housing, seals the opening when unused, and is pulled out in one direction to open the opening when used; and a loosening regulation unit that is provided on the housing or the sheet member, and regulates loosening of the sheet member, wherein the housing has a guide hole, the guide hole allowing the sheet member to be inserted in when sealing the opening with the sheet member, and guiding the sheet member when the sheet member is pulled out.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority under 35 USC 119 from a Japanese patent application No. 2008-204119 filed on Aug. 7, 2008. 
       BACKGROUND  
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a developing device, a process cartridge, an image forming device, and a developer container. 
         [0004]    2. Related Art 
         [0005]    In recent years, a large number of recording devices/printers utilizing electrophotographic principles, with improved operationality have been introduced in the market. These improved devices are provided with a cartridge (a so-called process cartridge), which integrates members for executing an electrophotographic process. 
         [0006]    Further, components constituting such a process cartridge are improved to meet demands for downsizing of recording devices. One such component is a developing device. In the developing device, a developer container part is formed in advance. The developer in the developer container part is transported outside through an outlet opening. 
       SUMMARY  
       [0007]    The invention provides a developing device, a process cartridge, an image forming device, and a developer container, which prevent a sheet member from being cut when the sheet member is pulled out to open an opening. 
         [0008]    According to one aspect of the invention, a developing device includes: a housing that has a developer containing part and an opening, the developer containing part containing a developer, and the opening allowing the developer to flow through; a sheet member that is provided in the housing, seals the opening when unused, and is pulled out in one direction to open the opening when used; and a loosening regulation unit that is provided on the housing or the sheet member, and regulates loosening of the sheet member, wherein the housing has a guide hole, the guide hole allowing the sheet member to be inserted in when sealing the opening with the sheet member, and guiding the sheet member when the sheet member is pulled out. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0009]    An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
           [0010]      FIG. 1  shows a whole structure of an image-forming device according to an exemplary embodiment of the invention; 
           [0011]      FIG. 2  is a perspective view showing a developing device according to the exemplary embodiment; 
           [0012]      FIG. 3  is an exploded perspective view showing a main part of the developing device according to the exemplary embodiment; 
           [0013]      FIG. 4  is a partial cross-sectional view observed in a direction defined by arrows IV in  FIG. 2 ; 
           [0014]      FIG. 5  is a perspective view showing a partition frame and a sheet member; 
           [0015]      FIG. 6  is a partial cross-sectional view observed in a direction defined by arrows IV in  FIG. 4 ; 
           [0016]      FIG. 7  is a partial cross-sectional view according to Modification 1, observed in the same direction as in  FIG. 6 ; 
           [0017]      FIG. 8  is a perspective view according to Modification 3, observed in the same direction as in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION  
     1. Whole Structure of Image Forming Device 
       [0018]      FIG. 1  shows a whole structure of an image-forming device  1  in which a developing device according to the exemplary embodiment is used. 
         [0019]    The image-forming device  1  is a color image-forming device of a so-called tandem type. In a device housing  2 ) image-forming units  11  (e.g., 11Y, 11M, 11C, and 11B) for four colors (yellow, magenta, cyan, and black in this exemplary embodiment) are arrayed in a longitudinal direction. Below the image-forming units  11 , there is provided a sheet feed cassette  61 , which contains paper sheets P to be supplied. Through positions corresponding to the image-forming units  11 , a sheet conveyance path  62  is set extending in a longitudinal direction, and serves as a route for conveying the paper sheets P from the sheet feed cassette  61 . 
         [0020]    The image-forming units  11  function to form toner images for yellow, magenta, cyan, and black colors, in an order from an upstream side of the sheet conveyance path  62 . Each of the image-forming units  11  has a process cartridge and an exposure device  21 . Various process units are built into the process cartridge  12 , and the exposure device  21  illuminates the process cartridge  12  with scanning light for forming images. 
         [0021]    The process cartridge  12  integrates, into one cartridge, a photo-sensitive drum  13 , an electric charge roll  14 , a developing device  30 , and a cleaning device  15 . The electric charge roll  14  electrically charges the photo-sensitive drum  13  in advance. The developing device  30  visualizes an electrostatic latent image by a color toner (having a negative polarity in this exemplary embodiment), wherein the electrostatic latent image has been exposed and formed on the electrically charged photo-sensitive drum  13  by the exposure device  21 . The cleaning device  15  removes a waste toner on the photo-sensitive drum  13 . The developing device  30  is detachably attached to a base of the process cartridge  12  (not shown in the figures). 
         [0022]    Meanwhile, the exposure device  21  has a semiconductor laser, a polygon mirror, an imaging lens, and a mirror, which are contained in a casing. A light beam from the semiconductor laser is deflected by the polygon mirror, so as to scan exposure points on the photo-sensitive drum  13  by guiding a light image through the imaging lens and the mirror. 
         [0023]    Further, a conveyor belt  63  is provided, which circulates and moves along the sheet conveyance path  62  and extends through positions corresponding to the photo-sensitive drums  13  of the image forming units  11 . The conveyor belt  63  is made of a belt material (rubber or resins) capable of electrostatically attracting a paper sheet P, and is wound between a pair of tension rolls  64  and  65 . 
         [0024]    A sheet attraction roll  66  is provided at a start position of the conveyor belt  63  (i.e., a position opposite the tension roll  64 ). As a high attraction voltage is applied to the sheet attraction roll  66 , a paper sheet P is attracted by the conveyor belt  63 . Transfer rolls  67  are provided on the back surface side of the conveyor belt  63 , respectively corresponding to the photo-sensitive drums  13  of the image-forming units  11 . The photo-sensitive drums  13  and the paper sheet P on the conveyor belt  63  are kept in tight contact with each other by the transfer rolls  67 . Further, a predetermined transfer bias is applied between the transfer rolls  67  and the photo-sensitive drums  13  by a transfer bias power supply. 
         [0025]    Further, the sheet feed cassette  61  is provided with a pickup roll  71  which feeds out paper sheets P each at predetermined timing, and feeds the paper sheets P through a conveyor roll  72  and a registration roll  73  to transfer positions. 
         [0026]    A fixing device  74  is provided on the sheet convey path  62 , at a position in a further downstream side of the image-forming unit  11 B which exists in the most downstream side among the image-forming units  11 . Plural sheet output rolls  76  for outputting paper sheets are provided in the downstream side of the fixing device  74 . Paper sheets are output ad stored in a container part  77  formed above the device housing  2 . 
         [0027]    In the image-forming device configured as described above, image formation is carried out through a process as follows. 
         [0028]    In each of the image-forming units  11  (11Y, 11M, 11C, and 11B), the electric charge roll  14  electrically charges the photo-sensitive drum  13 , and a latent image is formed on the photo-sensitive drum  13  by the exposure device  21 . Thereafter, a visible image (toner image) is formed by the developing device  30 . 
         [0029]    Meanwhile, a paper sheet P is fed out at predetermined timing by the pickup roll  71  and is fed to an attraction position of the conveyor belt  63  through the conveyor roll  72  and the registration roll  73 . The paper sheet P attracted by the conveyor belt  63  is then fed to transfer positions. 
         [0030]    Toner images on the photo-sensitive drums  13  of the image forming units  11  are sequentially transferred to the paper sheet P by the transfer rolls  67 . Toner images for respective color components on the paper sheet P are then fixed by the fixing device  74 , and the paper sheet P subjected to the fixing of the toner images is then output to the container unit  77 . 
       2. Outline of Process Cartridge 
       [0031]    The process cartridge  12  has a photo-sensitive drum  13 , an electric charge roll  14 , a developing device  30 , and a cleaning device  15 . 
       3. Outline of Developing Device 
       [0032]      FIGS. 2 to 4  are views showing a developing device  30  according to this exemplary embodiment.  FIG. 2  is a perspective view of the developing device  30 .  FIG. 3  is an exploded perspective view of a main part of the developing device  30 .  FIG. 4  is a cross-sectional view seen from a direction defined by arrows IV in  FIG. 2 . In the description below, a widthwise direction and a lengthwise direction of the developing device  30  are X- and Y-axes, respectively. 
         [0033]    As shown in  FIGS. 2 and 3 , the developing device  30  has a housing  31 , an agitation auger  41 , a feed auger  42 , a magnetic roll  43 , a trimmer member  44 , and a paddle  45 . The housing  31  includes an opening  31 A and a chamber divided into a developer container part  35  and a developing part  36 . The agitation auger  41  and feed auger  42  are located in the developer container part  35 . The magnetic roll  43 , trimmer member  44 , and paddle  45  are located in the developing part  36 . 
         [0034]    A part of the magnetic roll  43  is exposed from the opening part  31 A of the housing  31  and is located near the photo-sensitive drum  13 . The trimmer member  44  regulates an mount of a developer held on a surface of the magnetic roll  43 . A paddle  45  returns the developer released from the magnetic roll  43  after completion of development. Further, torque of a drive source is transmitted to the agitation auger  41 , feed auger  42 , magnetic roll  43 , and paddle  45  through gears (none of which is shown in the figures). 
         [0035]    The housing  31  is constituted of a lower housing  32 , an upper housing  33 , and side covers  34  arranged in the left and right sides of the upper and lower housings. The housing  31  is formed by assembling the parts  32  to  34 , and is divided into the developer container part  35  and the developing part  36 . A developer G is filled in the developer container part  35 . 
         [0036]    Further, as shown in  FIG. 4 , a groove is formed in the housing  31  at a position of a boundary between the developer container part  35  and the developing part  36 . This groove is constituted of a lower groove  37  formed in the lower housing  32 , an upper groove  38  formed in the upper housing  33 , and the grooves formed in the side covers  34  which are omitted from the figure. When the developing device is not used, a partition frame  46  to which a sheet member  48  is bonded is engaged in the groove. 
         [0037]    Meanwhile, a developer receiving part  50  is formed on one side of the upper housing  33  in the lengthwise direction. 
         [0038]    The partition frame  46  and the sheet member  48  will now be described with reference to  FIG. 5 . 
         [0039]      FIG. 5  shows a relationship between the partition frame  46  and the sheet member  48 . The partition frame  46  has an outlet opening  47  through which the developer container part  35  and the developing part  36  communicate with each other. The outlet opening  47  communicates with the opening  31 A (of the developing part  36 ) of the housing  31  through the developing part  36 . As the sheet member  48  opens and/or closes, the developer container part  35  and the opening  31 A (of the developing part  36 ) are connected to or disconnected to each other. 
         [0040]    Further, the sheet member  48  is formed by layering a base layer and a thermal welding layer (both not shown). The base layer is formed, as a film having a thickness between 20 μm (micrometers) and 50 μ(micrometers), of polyester, polypropylene, polystyrene, or nylon. The thermal welding layer is formed as a film having a thickness between 20 μm (micrometers) and 40 μm (micrometers) of a polyethylene-based sealant, which contains ethylene vinyl acetate copolymer at several % to several ten %. 
         [0041]    Further, the sheet member  48  is bonded, at the peripheries by an adhesive agent, to one side surface of the partition frame  46  so as to seal the outlet opening  47 . The sheet member  48  is bonded so as to extend forward and return backward along a lengthwise direction (Y-axis) of the partition frame  46 . Therefore, the sheet member  48  is twice as or more than twice as long as the developing device  30 . A part of the sheet member  48 , which is shown in a front side of  FIG. 5  is a folded part  48 A. A part of the sheet member  48  from a base end of the sheet member  48  to the folded part  48 A is a forward part  48 B which is bonded to the partition frame  46 . A part of the sheet member  48  from the folded part  48 A to a free end is a backward part  48 C. This free end is led outside through a guide hole (not shown in the figures) formed between the upper housing  33  and the lower housing  32  and through a sheet path (not shown in the figures) in a side cover  34 . 
         [0042]    When separating the sheet member  48  off from the partition frame  46 , the free end, which is led outside through the side cover  34  is pulled in a direction of an arrow A. The backward part  48 C is pulled to the rear side in the figure, and the folding part  48 A accordingly moves to the rear side. The rear side (in the figure) of the forward part  48 B is accordingly separated from the partition frame  46 . Thus, the sheet member  48  is separated from the partition frame  46  and the outlet opening  47  opens accordingly, thereby connecting the developer container part  35  to the developing part  36 . 
         [0043]    Next, the structure of the developer receiving part  50  will now be described with reference to  FIGS. 4 to 6 .  FIG. 6  is a cross-sectional view seen from a direction defined by arrows VI in  FIG. 4 . 
         [0044]    The developer receiving part  50  is formed in a shape such as a half barrel on the upper housing  33 . The developer receiving part  50  has an outer part  50 A, a cover part  50 C, and a spring  50 E. The outer part  50 A has a long regulation hole  50 B formed extending in a lengthwise direction (X-axis direction) of the half barrel. A protrusion  50 D to be engaged in the regulation hole  50 B is protruded from the cover part  50 C. The spring  50 E presses the cover part  50 C in a direction of closing the cover part  50 C. An inlet opening  51  is formed at a position on the housing  31  where the developer receiving part  50  is formed. 
         [0045]    Next, the developer receiving part  50  and a sheet member  52  will be described below. The sheet member  52  is bonded, at boundaries, to an inner surface of the upper housing  33  so as to seal the inlet opening  51 . As shown in  FIG. 6 , the sheet member  52  has a folding part  52 A in the left side of the figure. A part of the sheet member  52  from a base end to the folding part  52 A is a forward part  52 B, which is bonded to the peripheries of the inlet opening  51 . A part of the sheet member  52  from the folding part  52 A to a free end  52 D is a backward part  52 C. The free end  52 D of the sheet member  52  is led outside through the guide hole  53  formed on the upper housing  33  and a seal member  54  bonded to the lower housing  32 , and further through a sheet path (not shown in the figures) formed on the side covers  34 . 
       4. Features of Exemplary Embodiment  
       [0046]    The developing device  30  according to this exemplary embodiment has a feature that the sheet member  52 , which seals the inlet opening  51 , is provided with a press plate  81  as a loosening regulation unit, which is positioned between t he backward part  52 C of the sheet member  52  and the lower housing  32 , as shown in  FIG. 6 . The sheet member  48 , which seals the outlet opening  47 , is also provided with a loosening regulation unit. The latter loosening regulation unit has the same structure and operations as the former loosening regulation unit and a detailed description of the latter loosening regulation unit will therefore be omitted herefrom. 
         [0047]    The press plate  81  is sandwiched between the backward part  52 C of the sheet member  52  and the seal member  54  (of the lower housing  32 ). A base end  81 A of the press plate  81  protrudes outside from the housing  31 , like the free end  52 D of the sheet member  52 . A distal end  81 B of the press plate  81  extends to the center of the inlet opening  51 . 
         [0048]    The press plate  81  may have a width, which is between 25% and 100% of that of the sheet member  52  or longer than a size of the press plate  81  in the X-axis direction. Further, the press plate  81  is formed of a harder material than that of the sheet member  52 . For example, a metal, plastic, or wooden material processed to have a thickness between 0.05 mm to 2 mm may be used as the press plate  81 . This exemplary embodiment utilizes PET (polyethylene terephthalate) having a thickness of 0.1 mm. 
         [0049]    In this manner, the press plate  81  has a shape which presses the backward part  52 C toward the forward part  52 B, so that the backward part  52 C is prevented from floating up from the forward part  52 B, thereby reducing flexure. Further, movement of the sheet member  52  is regulated since the sheet member  52  presses the backward part  52 C toward the forward part  52 B (toward the inlet opening  51  ). 
         [0050]    In the developing device  30  according to this exemplary embodiments the press plate  81  provided for the sheet member  52  prevents the backward part  52 C of the sheet member  52  from floating up from the foward part  52 B. The backward part  52 C is thereby prevented from loosening, and movement of the backward part  52 C is regulated. As a result, even when the developing device  30  vibrates due to transportation or the like, the sheet member  52  is prevented from loosening and from creating a gap between parts of the sheet member  52  itself. Accordingly, a gap in which a developer G may be caught and accumulated is prevented from being created. 
         [0051]    When pulling out the sheet member  52  by pulling the free end  52 D to outside, the press plate  81  sandwiched between the sheet member  52  and the lower housing  32  is pulled out together with the sheet member  52 . The press plate  81  is therefore prevented from remaining in the developer containing part  35 , thereby closing the inlet opening  1 , and from touching any other part. 
       5. Modifications 
       [0052]    The invention is not limited to the exemplary embodiment as described above but is practicable in other various forms For example, the invention may be modified as follows in practice. 
         [0053]    5-1. Modification 1 
         [0054]    In Modification 1, the lower housing  32  is provided with a press plate  82  as shown in  FIG. 7 . The press plate  82  is made of an L-shaped bent plate member. A base end  82 A of the press plate  82  is fixed to inside of the housing  32  on a side of the seal member  54 . A top end  82 B extends to an edge of the inlet opening  51 . The press plate  82  is formed of a harder material than that of the sheet member  52 . 
         [0055]    The press plate  82  described above operates and functions in the same manner as in the exemplary embodiment. That is, the press plate  82  prevents the backward part  52 C from floating up from the forward part  52 B. The backward part  52 C is thereby prevented from loosening, and movement of the backward part  52 C is regulated. 
         [0056]    5-2. Modification 2 
         [0057]    In Modification 2, a press plate  83  as shown in  FIG. 8  is provided in the upper housing  33  and the press plate  83  is made of a plate member, which is bent like inverted “V”. A base end  83 A of the press plate  83  is fixed to inside of the upper housing  33  in a deep side of the inlet opening  51 . A front end  83 B extends to the folded part  52 A of the sheet member  52  (or to an edge of the inlet opening  51  in the other side). The press plate  83  is formed of a harder material than that of the sheet member  52 . 
         [0058]    The press plate  83  described above regulates movement of the folded part of the sheet member  52 . Accordingly, the backward part  52 C is prevented from floating up from the forward part  52 B and from loosening as a result. 
         [0059]    5-3. Modification 3 
         [0060]    In Modification 3, a press plate  84  as shown in  FIG. 9  is bonded to the backward part  52 C of the sheet member  48 . The press plate  84  is formed of a harder material than that of the sheet member  48 . 
         [0061]    The press plate  84  prevents the backward part  52 C of the sheet member  48  from floating up from the forward part  52 B and from loosening as a result. 
         [0062]    5-4. Modification 4 
         [0063]    The exemplary embodiment and Modifications 1 and 2 have exemplified a case that the sheet member  52  is prevented from loosening by a press plate as a loosening regulation unit. Modification 3 has exemplified a case that the sheet member  48  is prevented from loosening by a press plate. However, press plates may be provided for both of the sheet members  48  and  52 . 
         [0064]    Further, the loosening regulation unit is not limited to a press plate but may be any member insofar as the member regulates loosening of the sheet member. 
         [0065]    5-5. Modification 5 
         [0066]    The exemplary embodiment and Modifications have exemplified a case that a loosening regulation unit is used in the developing device  30 . Needless to say, however, the invention is not limited to this case but is applicable to a developer container, which has a developer containing part and uses a sheet member to seal an opening in a developer containing part.