Abstract:
A toner container for accommodating toner, includes a first opening through which the toner is passable; a toner feeding member for feeding the toner to the first opening by reciprocating motion toward and away from the first opening; an urging member for urging the toner feeding member; a movable member movable between a position for moving the toner feeding member against an urging force of the urging member and a position for permitting the toner feeding member to move by the urging force of the urging member; a second opening for permitting the urging member and the toner feeding member to pass into the toner container to install them in the toner container; and a cap for closing the second opening.

Description:
FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to a toner container, a developing apparatus (device), and a process cartridge, which are employed by an image forming apparatus such as a facsimile machine, a printer, etc. 
     In recent years, image forming apparatuses have been significantly reduced in size. Thus, it has become necessary to significantly reduce a process cartridge in thickness. This reduction in the thickness of a process cartridge has created various problems. One of the problems is how to create a toner container thin enough to be suitable for a process cartridge which is significantly thinner than a conventional process cartridge. More specifically, conventionally, the toner in a toner container is conveyed, white being stirred, by the rotational stirring (conveying) member in the container. Thus, the container size is closely related to the radius of the circular sweeping range of the stirring member. Therefore, it has been rather difficult to reduce in thickness a toner container in thickness. One of the solutions to this problem is disclosed in Japanese Laid-open Patent Application H04-178671. In the case of the process cartridge disclosed in this patent application, its toner container is not provided with a rotational toner conveying (stirring) member. Instead, it is provided with a toner conveying member which is in the form of a piece of thin plate and is reciprocally moved in the direction in which the toner in the toner container is to be conveyed. Thus, this process cartridge is significantly thinner than any of the process cartridges in accordance with the prior art. 
     Referring to  FIG. 11 , which is a sectional view of the developing device disclose in Japanese Laid-open Patent Application H04-178671, the toner container  211  is in the form of a long and thin parallelepiped, being therefore significantly thinner compared to a conventional toner container. It has an opening  211   c  (first opening), which is next to a development roller  217 . It has also a stirring member  219  and a toner conveying member  213 . The toner stirring member  219  is on the immediately inward side of the first opening  211   c , and is significantly smaller in the radius of its sweeping range than a conventional stirring member. The toner conveying member  213  is thin and long, being roughly rectangular. Its lengthwise edges are parallel to the lengthwise direction of the cartridge, and its widthwise edges are parallel to the widthwise direction of the cartridge. 
     The downstream end of the toner conveying member  213  in terms of the toner conveyance direction is provided with a pair of elongated holes, and is supported by the stirring member  219  which is rotationally driven. There are a pair of compression springs  214  (pressure applying member) between the other end of the toner conveying member  213  and the rear wall of the toner container  211 . 
     The stirring member  219  is fitted with a sector gear (unshown). As driving force is transmitted to the sector gear from an external power source, the stirring member  219  is rotated in the direction indicated by an arrow mark U in  FIG. 11 . More specifically, while the driving force is transmitted to the sector gear, the toner conveying member  213  is moved in the direction to compress the compression springs  214  (direction indicated by arrow mark V). Then, as the transmission of the driving force to the sector gear stops, the toner conveying member  213  is moved by the compression springs  214  in the direction to release the pressure stored in the springs  214 . 
     The art disclosed in Japanese Laid-open Patent Application H04-178671 can provide a toner container  211  which is significantly thinner than a conventional toner container. However, when it is assembled, the toner conveying member  213 , compression springs  214 , and stirring member  219  have to be installed in the toner container  211  through the first opening  211   c , which is very narrow. In other words, the toner container  211  is rather difficult to assemble. 
     SUMMARY OF THE INVENTION 
     Thus, the primary object of the present invention is to provide a developing apparatus (device) which is significantly thinner and easier to assemble than a conventional developing apparatus (device), and an image forming apparatus having such a developing apparatus (device). 
     A toner container for accommodating toner, includes a first opening through which the toner is passable; a toner feeding member for feeding the toner to the first opening by reciprocating motion toward and away from the first opening; an urging member for urging the toner feeding member; a movable member movable between a position for moving the toner feeding member against an urging force of the urging member and a position for permitting the toner feeding member to move by the urging force of the urging member; a second opening for permitting the urging member and the toner feeding member to pass into the toner container to install them in the toner container; and a cap for closing the second opening. 
     According to the present invention, it is possible to provide a toner container which is significantly thinner than a conventional toner container, and has an opening (second opening) through which its toner conveying member and pressure applying member(s) are installable in the container, being therefore significantly easier to assemble than a conventional toner container. 
     These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of the developing device in the first embodiment of the present invention. 
         FIG. 2  is a schematic sectional view of the image forming apparatus in the first embodiment of the present invention, and shows the general structure of the apparatus. 
         FIG. 3  is a schematic sectional view of the process cartridge in the first embodiment of the present invention, and shows the general structure of the cartridge. 
         FIG. 4(   a ) is a schematic sectional view of the developing device in the first embodiment of the present invention, and shows the general structure of the device.  FIG. 4(   b ) is an enlarged view of the top half of the portion of  FIG. 4(   a ) circled by the left circle in the drawing, and  FIG. 4(   c ) is an enlarged view of the top half of the portion of  FIG. 4(   a ) circled by the right circle in the drawing. 
         FIG. 5  is a perspective view of the developing device (minus its top lid) in the first embodiment of the present invention. 
         FIG. 6  is a drawing for describing the movement of the toner conveying member in the first embodiment. 
         FIG. 7  is a partial plan view of the rotational member different in shape from the one in the first embodiment. 
         FIG. 8  is a perspective view of a toner conveying member different in design from the one in the first embodiment in that it has a pair of leaf springs instead of the pair of compression springs. 
         FIG. 9  is a schematic perspective view of a toner container different in design from the one in the first embodiment in that its pressure applying means is a single tension spring instead of the pair of compression springs. 
         FIG. 10  is a drawing for describing a toner conveying member different in structure from the one in the first embodiment. 
         FIG. 11  is a schematic sectional view of an example of a typical thin developing device in accordance with the prior art. 
         FIG. 12  is a schematic sectional view of one of the modified version of the developing device in the first embodiment, and is for describing the toner stirring portion of its rotational member. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
     First, referring to  FIGS. 2 and 3 , the developing device and image forming apparatus in the first preferred embodiment of the present invention are described.  FIG. 2  is a schematic sectional view of the image forming apparatus A in the first embodiment of the present invention. It shows the general structure of the apparatus A.  FIG. 3  is a schematic sectional view of the process cartridge B in the first embodiment. It shows the general structure of the cartridge B. 
     The image forming operation of the apparatus A is as follows: Referring to  FIGS. 2 and 3 , a photosensitive drum  7 , that is, an image bearing member in the form of a drum, is charged by a charge roller  8  across its peripheral surface. Then, the charged portion of the peripheral surface of the photosensitive drum  7  is scanned by (exposed to) the beam of laser light projected, while being modulated with the image formation signals, upon the peripheral surface of the drum  7  from an optical system  1 , through the exposure opening  9  of the cartridge. As a result, an electrostatic latent image is effected on the peripheral surface of the photosensitive drum  7 . This electrostatic latent image is developed by the developing device  10  into a visible image, that is, an image formed of toner, with the use of the toner in the developing device  10 . 
     Meanwhile, the sheets  2  of recording medium stored in layers in a cassette  3   a  are fed one by one, while being separated from the rest, into the main assembly of the image forming apparatus A, by the pickup roller  3   b  and sheet separating member  3   c . Then, each sheet  2  is conveyed to the nip T (transfer station) between the photosensitive drum  7  in the process cartridge B and the transfer roller  4  (transferring means) of the apparatus main assembly. Then, the sheet  2  is conveyed through the nip T. While the sheet  2  is conveyed through the nip T, the toner image formed on the peripheral surface of the photosensitive drum  7  is transferred onto the sheet  2 . Then, the sheet  2  is conveyed to the fixing device  5 . 
     Then, the sheet  2  is conveyed through the fixing device  5 . While the sheet  2  is conveyed through the fixing device  5 , the sheet  2  and the toner image thereon are subjected to heat and pressure by a combination of the driver roller  5   a  and heater  5   b  of the fixing device  5 . As a result, the toner image is fixed to the sheet  2 . After the fixation of the tone image, the sheet  2  is discharged from the main assembly of the image forming apparatus A by a pair of discharge rollers  3   d  through the print outlet  6 . As for the toner remaining on the peripheral surface of the photosensitive drum  7  after the transfer, it is scraped down from the photosensitive drum  7  by a cleaning blade  32 , is scooped up by a scooping sheet  33 , and then, is recovered into the residual toner storage  34   a.    
     (Process Cartridge B) 
     Next, referring to  FIG. 3 , the process cartridge B has a cleaning device  31  and the developing device  10 . The cleaning device  31  has a drum supporting frame  34 , which rotatably supports the photosensitive drum  7 . The aforementioned cleaning blade  32  and charge roller  8  are in this drum supporting frame  34  and are attached to the drum supporting frame  34 . 
     The developing device  10  has a toner container  11 , which has a toner chamber  11   b . The development roller  17  which the process cartridge B has is attached to the frame of the toner container  11 . The developing device  10  is rotatably supported by the drum supporting frame  34 . The lengthwise ends of the development roller  17  are fitted with a pair of spacer rings  24  (gap regulation members), one for one, which keep the development roller  17  parallel to the photosensitive drum  7  with the presence of a preset amount of gap between the roller  17  and drum  7 . 
     (Developing Device  10 ) 
     Next, referring to  FIG. 4(   a ) which is a schematic sectional view of the developing device  10  in this embodiment and shows the general structure of the device, the developing device  10  comprises the toner container  11 , a toner container lid  15 , a stationary magnet  16 , the development roller  17 , a development blade  18 , a development roller gear  22 , and a stirring member gear  23 . 
     The toner container  11  has a development chamber  11   a , the toner chamber lib, the first opening  11   c , and a second opening  11   d . The development chamber  11   a  and toner chamber lib are separated from each other by the first opening  11   c . There are a rotational member  12 , the toner conveying member  13 , the pair of compression springs  14  (pressure applying members), and a toner stirring member  19  in the toner chamber lib. 
     The second opening  11   d  is the opening through which the toner conveying member  13 , toner stirring member  19 , and rotational member  12  can be placed in the toner chamber  11   b . The second opening  11   d  is kept covered by the toner container lid  15 . 
     The toner in the toner chamber  11   b  is conveyed to the adjacencies (development roller side) of the development roller  17  by the reciprocal movement of the toner conveying member  13 . Then, the toner stirring member  19  conveys the toner to the development roller  17  in the development chamber  11   a  through the first opening  11   c  by being rotated. There is the stationary magnet  16  in the hollow of the development roller  17 . Thus, as the development roller  17  is rotated, the toner in the adjacencies of the development roller  17  is borne on the peripheral surface of the development roller  17 , and is formed by a development blade  18 , into a layer of toner which is uniform in thickness, while being frictionally charged by the blade  18 . Then, the toner particles in the toner layer on the peripheral surface of the development roller  17  transfer onto the peripheral surface of the photosensitive drum  7 , in the pattern of the electrostatic latent image on the peripheral surface of the photosensitive drum  7 , forming thereby a visible on the peripheral surface of the photosensitive drum  7 , of the toner, in the pattern of the electrostatic latent image. 
     The toner conveying member  13  is in contact with the bottom surface  11   f  of the toner chamber  11   b , and conveys the toner by being reciprocally moved in contact with the bottom surface  11   f . Thus, the portion of the bottom surface  11   f  of the toner chamber  11   b , which is in contact with the toner conveying member  13 , is flat, smooth, and parallel to the bottom surface of the toner conveying member  13 . That is, the toner conveying member  13  is reciprocally slidable on the bottom surface  11   f  of the toner chamber  11   b.    
     Next, referring to  FIG. 5  which is a perspective view of the developing device  10  (minus its top cover) in this embodiment, there are the development roller  17 , development blade  18 , and development roller gear  22  in the development chamber  11   a . The development blade  18  is solidly attached to the frame of the toner container  11  with the use of small screws (unshown). The toner stirring member  19  is rotatably attached to the frame of the toner container  11 , like the rotational member  12 . The toner stirring member gear  23  is solidly attached to the shaft of the toner stirring member  19 . The toner stirring member  19  (which hereafter may be referred to simply as stirring member  19 ) is rotated in the direction indicated by an arrow mark S in  FIG. 4(   a ). 
     The development roller gear  22  is in mesh with the photosensitive drum gear (unshown). Thus, the rotational driving force is transmitted from the main assembly of the image forming apparatus to the development roller gear  22  by way of the photosensitive drum gear (unshown). Further, the development roller gear  22  rotates the stirring member  19  by way of the stirring member gear  23 . It rotates the rotational member  12  by way of the rotational member gear  21 . 
     Referring again to  FIG. 4(   a ), the rotational member  12  is rotatably supported by the frame of the toner container  11 , and is fitted with a pair of cams  12   a . More specifically, each cam  12   a  is solidly attached to the shaft  12   d  of the rotational member  12  with the use of an elastic pin or the like. Thus, as the rotational member  12  is rotated in the direction indicated by an arrow mark Q, the cams  12   a  rotate in the direction of the arrow mark Q, while intermittently pressing the toner conveying member  13  in the direction indicated by an arrow mark X. Further, the developing device  10  is provided with a pair of compression springs  14  which are between the toner conveying member  13  and the frame of the toner container  11 , and the toner conveying member  13  is kept pressured toward the development roller  17  (direction indicated by arrow mark X) by the compression springs  14 . Therefore, as the rotational member  12  is rotated, the toner conveying member  13  is made to intermittently and reciprocally (direction indicated by arrow mark −X or direction indicated by arrow mark X) move by the combination of the cams  12  and compression springs  14 . That is, the rotational member  12  is a rotatable member, and is capable of being in the state in which it presses the toner conveying member  13  in the direction indicated by the arrow mark X against the resiliency of the compression springs  14 , and in the state in which it allow the toner conveying member  13  to be moved in the direction indicated by the arrow mark −X by the resiliency of the compression spring  14 . 
     Next, referring to  FIG. 5 , each of the lengthwise end walls of the toner container  11  is provided with a toner conveying member regulating portion  11   e , which is for regulating the movement of the toner conveying member  13  in terms of the lengthwise direction of the toner container  11 , that is, the direction (indicated by arrow mark X) perpendicular to the direction in which the compression spring  14  presses on the toner conveying member  13 . Each toner conveying member regulating portion  11   e  protrudes inward of the toner container  11  by a preset distance from the inward surface of the corresponding lengthwise end wall of the toner container  11 . It regulates the toner conveying member  13  in terms of the movement of the toner conveying member  13  in the lengthwise direction of the toner container  11 . The developing device  10  is provided with two compression springs  14  which are at the lengthwise ends of the toner container  11  one for one. Therefore, the toner conveying member  13  is kept stable in attitude while remaining under the pressure from the compression springs  14 . Referring again to  FIG. 4(   a ), the top lid  15  of the toner container  11  has a pair of toner conveying member regulating portions  15   a , which project inward of the container  11 . The regulating portions  15   a  prevent the toner conveying member  13  from becoming afloat from the bottom wall  11   f  of the toner container  11 , in the direction perpendicular to the lengthwise direction of the member  13  and the direction in which the member  13  is kept pressed by the compression springs  14 . That is, the toner conveying member regulating portions  15   a  prevent the toner conveying member  13  from separating from the bottom surface  11   f  of the toner container  11 , that is, the surface with which the toner conveying member  13  is required to remain in contact. Designing the toner container  11  so that the toner conveying member regulating member  15   a  is an integral part of the toner container lid  15  makes it possible to integrate the process of attaching the toner container lid  15  to the main structure of the toner container  11 , with the process of properly positioning the toner conveying member  13  in the toner container  11 , making it easier to assembly the toner container  11 . 
     Next, referring to  FIG. 4(   b ) which is an enlarged view of the top half of the portion of  FIG. 14(   a ) surrounded by the circle on the development roller side of the drawing, the toner conveying member  13  is provided with a pair of projections  13   d , which are perpendicular to the bottom surface  11   f  of the toner chamber  11   b  after the installation of the toner conveying member  13  into the toner container  11 . The projections  13   d  are positioned so that after the installation of the toner conveying member  13 , they will be in the adjacencies of the development roller  17 , and will be at the lengthwise ends of the toner conveying member  13 , one for one. 
     Next, referring to  FIG. 4(   c ) which is an enlarged view of the top half of the portion of  FIG. 4(   a ) surrounded by the circle on the compression spring side, the toner conveying member  13  is made up of an external frame, and multiple parallel slats connected to the lengthwise ends of the frame, being thereby provided with multiple holes  13   a , which are trapezoidal in cross-section at a plane perpendicular to the lengthwise direction of the member  13 . The holes  13   a  are wider at the top than at the bottom in terms of the widthwise direction of the member  13 . Each hole  13   a  functions as a portion in which the toner conveying member  13  holds toner. Further, each slat, that is, the portion of the toner conveying member  13 , which is between the adjacent two holes  13   a  of the member  13 , is also trapezoidal in cross-section at a plane parallel to the lengthwise direction of the member  13 . It has a surface  13   e  and a surface  13   f . The surface  13   e  faces toward the compression springs  14  and is acutely angled relative to the moving direction of the toner conveying member  13  toward the compression springs  14 , whereas the surface  13   f  faces toward the development roller  17  (first opening  11   c ) and is roughly perpendicular to the bottom surface  11   f  of the toner chamber  11   b . In other words, each hole  13   a  is between the slanted surface  13   e  of a slat of the toner conveying member  13 , and the roughly vertical surface  13   f  of the next slat. 
     Providing the toner conveying member  13  with multiple holes  13   a  as described above makes it easier for the toner conveying member  13  to convey toner. More concretely, as the toner conveying member  13  is moved in the direction indicated by the arrow mark −X (toward first opening  11   c ), the toner held in each hole  13   a  is conveyed (moved) in the direction of the arrow mark −X by the toner conveyance surface  13   f , whereas as the member  13  is moved in the direction of the arrow mark X (away from first opening  11   c ), the toner in each hole  13   a  is made to slide over the slat of the toner conveying member  13  between the adjacent two holes  13   a , following the slanted surface  13   e , by the movement of the member  13 . That is, as the toner conveying member  13  is moved in the direction of the arrow mark X, the toner in a given hole  13   a  of the member  13  is made to move into the adjacent upstream hole  13   a  in terms of the movement of the member  13  in the direction of the arrow mark X. 
     The compression springs  14  are not to interfere with the toner conveyance. Therefore, they are positioned on the inward side of the toner conveyance member  13  as seen from the first opening side of the toner container  11 . Further, the compression springs  14  are to remain anchored, and it is only in the widthwise direction of the toner conveying member  13  (X direction or −X direction) that the compression springs  14  are to be allowed to expand, or compress. Thus, each compression spring  14  is anchored to the rib  13   b  (spring anchor) of the toner conveying member  13 ; one end of the compression spring  14  is fitted around the rib  13   b.    
     (Movement of Toner Conveying Member  13 ) 
     Referring to  FIG. 6(   a ), as the rotational member  12  is rotated in the direction indicated by an arrow mark Q, the toner conveying member  13  is pressed in the X direction by the cams  12   a  of the rotational member  12 . Thus, the toner conveying member  13  moves in the X direction while following the bottom surface  11   f  of the toner chamber  11   b , and compressing the compression springs  14  in the X direction. Consequently, a force which works in the direction to press the toner conveying member  13  in the −X direction is stored in the compression springs  14  as shown in  FIG. 6(   b ). 
     Next, referring to  FIG. 6(   c ), as the cam  12   a  is rotated further by the further rotation of the rotational member  12 , the amount of force applied to the toner conveying member  13  by the cams  12   a  reduces, being thereby overwhelmed by the resiliency of the compression springs  14 . Thus, the toner conveying member  13  is swiftly moved in the −X direction by the resiliency of the compression springs  14  until the compression springs  14  extend as far as they can. 
     A point D at which the downstream edge of the toner conveying member  13 , in terms of the direction in which the compression springs  14  expand, is when the compression springs  14  have extended as far as they are allowed is within the sweeping range C of the cams  12   a . It is also the point at which the cams  12   a  begin to push the toner conveying member  13  in the X direction as they continue to rotate. Then, as the rotational phase of the cams  12   a  become such that the cams  12   a  can press the toner conveying member  13 , the toner conveying member  13  begins to be pressed again by the cams  12   a , being thereby moved in the direction of the arrow mark X (state shown in  FIG. 6(   a )). 
     Thus, as the rotational member  12  is rotated, the toner conveying member  13  is reciprocally moved, whereby the toner is moved to the adjacencies of the toner stirring member  19 . That is, the developing device  10  is structured so that for each full rotation of the rotational member  12  (cams  12   a ), the cams  12   a  are in the state in which they are in contact with the toner conveying member  13  and press the toner conveying member  13 , or in the state in which they are not in contact with the toner conveying member  13  and do not press the toner conveying member  13 . The state in which the cams  12   a  are in contact with the toner conveying member  13  and press the toner conveying member  13  is equivalent to the state of the developing device  10  shown in  FIGS. 6(   a ) and  6 ( b ), whereas the state in which cams  12   a  are not in contact with the toner conveying member  13  and do not press the toner conveying member  13  is equivalent to the state of the developing device  10  shown in  FIG. 6(   c ). Regarding the speed at which the toner conveying member  13  is reciprocally moved, the speed at which the toner conveying member  13  is moved (rearward) by the pressure applied by the cams  12   a  of the rotational member  12  is different from the speed at which toner conveying member  13  is moved (forward) by the resiliency of the compression springs  14 . Therefore, the amount by which the toner is conveyed can be adjusted by adjusting the compression springs  14  in the amount of resiliency, instead of substantially changing the amount of torque applied to rotate the rotational member  12 . 
     (Assembly of Developing Device  10 ) 
       FIG. 1  is an exploded perspective view of the developing device  10  in this embodiment. It shows how the developing device  10  is to be assembled. Referring to  FIG. 1 , first, the rotational member  12  and toner stirring member  19  are to be placed in the toner container  11  through the second opening  11   d . During the placement of these components  12  and  19 , the rotational member  12  is to be in such a rotational phase that its cams  12   a  do not press the toner conveying member  13 , and the toner stirring member  19  is to be kept tilted. Further, the stirring member  19  is to be inserted so that its leading end, in terms of the stirring member insertion direction, fits into a first hole  11   g , with which the lengthwise end wall of the developing device frame (toner container frame) on the opposite side from the side from which the developing device  10  is driven, is provided. Incidentally, in order to make it easier for the stirring member  19  to be inserted into the first hole  11   g , the first hole  11   g  is chamfered on the side from which the stirring member  19  is inserted. In terms of the direction parallel to the axial line of the development roller  17  (lengthwise direction of toner container  11 ), the side from which the developing device  10  is not driven means the opposite side of the developing device  10  from the side where the development roller gear  22  ( FIG. 4 ) is attached. Thus, the lengthwise end of the toner container  11 , to which the development roller gear  22  (for development roller  17 ) is attached, is referred to as the “driving side”, and the opposite side of the toner container  11  from the “driving side” may be referred to as non-drive side”. 
     Next, the toner stirring member gear  23  is to be inserted into the toner container  11  from the “driving side”. The rotational member  12  also is to be inserted, while being kept tilted, into the toner container  11  through the second opening  11   d  as is the toner conveying member  13 , so that its leading end, in terms of its insertion direction, fits into a second hole  11   h , with which the lengthwise end wall of the toner container  11  on the “non-drive side” is provided. Then, the rotational member gear  21  is to be inserted into the second hole  11   h  to solidly fit the gear  21  around the lengthwise end of the rotational member  12  so that the gear  21  does not slip relative to the rotational member  12  in terms of their rotational direction. 
     Next, the compression springs  14  are to be attached to the toner conveying member  13 . More specifically, in terms of the lengthwise direction of the toner container  11 , the compression springs  14  are to be attached to the read end of the toner conveying member  13  as seen from where the development roller  17  will be after the completion of the developing device  10 . Further, in terms of the widthwise direction of the toner container, one of the compression springs  14  is attached to one end, and the other is attached to the other end. After the attachment of the compression springs  14 , the toner conveying member  13  is to be inserted into the toner chamber  11   b  through the second opening  11   d , in such a manner that after the insertion of the toner conveying member  13 , the toner conveying member  13  is in contact with the compression springs  14  and the compression springs  14  are in contact with the rear wall of the toner container  11 . 
     Next, the development blade  18  is to be attached to toner container  11  with the use of small screws, and then, the development roller  17  is to be placed in the development chamber  11   a . Then, a pair of development roller holder  20  are to be attached to the “driving side” end and “non-drive side” ends of the toner container  11 , one for one, so that the rotational member  12 , development roller  17 , and toner stirring member  19  are accurately positioned in terms of the lengthwise direction of the developing device (toner container  11 ). 
     After the attachment of all the components of the developing device  10  except for the toner container lid  15 , the toner container  11  is to be filled with toner through the second opening  11   d . Next, the toner container  11  is to be fitted with the toner container lid  15  so that the second opening  11   d  of the container  11  is covered with the lid  15 . Lastly, the lid  15  is to be welded to the toner container  11  to complete the developing device  10 . 
     Because the toner conveying member  13  is to be positioned between the pair of compression springs  14  and the first opening  11   c , it is difficult to accurately place the compression springs  14  in the toner container  11  through the first opening  11   c . In this embodiment, however, the toner container  11  is provided with the second opening  11   d  in addition to the first opening  11   c , and the second opening  11   d  is positioned so that where the toner conveying member  13  and compression springs  14  are to be placed in the toner container  11  are accessible through the second opening  11   d . That is, the developing device  10  is structured so that the toner conveying member  13  and compression springs  14  are placed on the bottom surface  11   f  of the toner container  11 , as the interior of the toner container  11  is seen from the second opening side ( FIG. 4(   a )). 
     In other words, when the developing device  10  is assembled, the toner conveying member  13  is not between the second opening and compression springs  14 . Therefore, where the compression springs  14  are to be placed can be directly accessed through the second opening  11   d , making it easier to attach the compression springs  14 . That is, even if the design of a given thin developing device is such that the compression springs  14  are behind the toner conveying member  13  as seen from the first opening side, the compression springs  14  and toner conveying member  13  can be easily installed in the toner container  11 . As is evident from the detailed description of the developing device  10  in the first embodiment of the present invention, the present invention can provide a toner container  11  which is significantly thinner and easier to assemble than any developing device in accordance with the conventional art. 
     Further, in this embodiment, the developing device  10  is structured so that the rotational member  12  is not one of the integral parts of the toner conveying member  13 , and can be placed in contact with, or separated from, the toner conveying member  13 . Thus, the compression springs  14  and toner conveying member  13  can be installed when there is a gap between the rotational member  12  and toner conveying member  13 . That is, it is when there is a gap between the rotational member  12  and toner conveying member  13 , and therefore, the rotational member  12  is not pressing the toner conveying member  13  that the compression springs  14  and toner conveying member  13  are to be installed. That is, in this embodiment, the toner conveying member  13  is independent from the rotational member  12  as described above, being therefore easier to install than the toner conveying member ( 13 ) of any thin process cartridge in accordance with the prior art. 
     Also in this embodiment, the compression springs  14  were used as the means for pressing the toner conveying member  13  toward the development roller  17 . However, the developing device  10  may be structured so that the rotational member  12  is rotated in the opposite direction from the rotational direction of the rotational member  12  in this embodiment, and a tension spring is employed in place of the compression springs  14 . 
     Further, instead of providing the rotational member  12  with the cams  12   a , the portions of the rotational member  12 , which corresponds in position to the cams  12   a , may be bent in the form of a crank. That is, all that is necessary is that as the rotational member  12  is rotated, the toner conveying member  13  is reciprocally moved by the combination of the cams  12   a  or the like (crank), and the compression springs  14  or tension spring, and also, that the closest point to the development roller  17  in terms of the moving direction of the toner conveying member  13 , which the toner conveying member  13  reaches when the member  13  is pressed by the compression springs  14  is in the sweeping range of the cam  12   a . As the rotational member  12  is rotated, its crank-like portions also press the toner conveying member  13  rearward of the toner container  11  so that the toner conveying member  13  is reciprocally moved. 
     Next, referring to  FIG. 8 , instead of providing the developing device  10  with the compression springs  14  as the means for moving the toner conveying member  13  toward the first opening  11   c , the toner conveying member  13  may be provided with a pair of leaf springs  13   c  (pressure applying members), or the toner container  11  may be provided with a toner conveying member pressing means which is integral with the frame of the toner container  11 . 
     Next, referring to  FIG. 9 , the developing device  10  may be provided with a tension spring  114  instead of the compression springs  14 . In a case where the developing  10  is provided with the tension spring  114 , the toner container  11  and toner conveying member  13  are provided with spring anchoring portions  11   j  and  113   b , respectively, and the tension spring  114  is placed between the two spring anchoring portions  11   j  and  113   b , that is, between the toner conveying member  13  and toner container  11 . 
     In the case where the developing device  10  is provided with the tension spring  114  instead of the pair of compression springs  14 , however, it is possible that the tension spring  114  will interfere with the toner conveyance by the toner conveying member  13 . One of the solutions to this problem is to provide the toner conveying slats which are adjacent to the tension spring  114 , with the second toner conveyance surface  13   a   3  as shown in  FIGS. 10(   a ) and  10 ( b ). The second toner conveyance surface  13   a   3  is roughly perpendicular to the bottom surface  11   f  of the toner chamber  11   b  ( FIG. 3) . More specifically, the toner conveyance slat is formed so that the angle θ between the axial line  114   a  (straight line) of the cylindrical portion of the tension spring  114  and the toner conveyance surface  13   a   3  becomes acute. Thus, as the toner conveying member  13  is made to shuttle, the toner in the adjacencies of the tension springs  114  is conveyed in the direction indicated by a pair of arrow marks in  FIG. 10(   c ), by the toner conveyance surfaces  13   a   3 . 
     That is, the toner conveyance surfaces  13   a   3  are in the adjacencies of the tension spring  114 , and diagonally face the tension spring  114 . Further, they are acutely angled relative to the direction in which the tension spring  114  pulls the toner conveying member  13  (which is opposite to direction in which spring  114  is extended). Therefore, the toner conveyance surfaces  13   a   3  convey the toner in the direction of where toner would not be conveyed without these surfaces  13   a   3 . 
     Even in a case where the leaf springs  13   c  or tension spring  114  are employed in place of the compression springs  14  as the pressure applying means, this embodiment of the present invention allows the pressure applying members and toner conveying member  13  to be installed into the toner container  11  through the second opening  11   d , making the process cartridge (developing device  10 ) in this embodiment easier in terms of the installation of the pressure applying members and toner conveying member  13  than any thin process cartridge (developing device  10 ) in accordance with the prior art. In other words, the present invention can make it easier to assembly the toner container  11 , that is, a thin toner container, and afford more latitude in the choice of the structural arrangement for conveying toner in the toner container  11 . 
     Lastly, referring to  FIG. 12 , the rotational member  12  may be provided with a toner stirring portion  12   c . The toner stirring portion  12  is a sheet of a desired choice of substance and is to be attached to the shaft  12   d  of the rotational member  12 . Thus, as the rotational member  12  is rotated, the toner stirring portion  12   d  stirs the developer in the adjacencies of the first opening  11   c . In the case of the toner container  11  shown in  FIG. 12 , it is a tension spring  54  instead of the compression springs  14  that is attached to the toner conveying member  13 . The tension spring  54  pulls the toner conveying member  13  in the direction indicated by an arrow mark X in  FIG. 12 . Thus, as the rotational member  12  is rotated in the direction indicated by an arrow mark F, it presses the toner conveying member  13  in the direction indicated by an arrow mark −X. Therefore, each time the rotational member  12  is rotated one full turn, it moves the toner conveying member  13  in the direction of the arrow mark −X against the resiliency of the tension spring  54 . Further, each time the rotational member  12  is rotated one full turn, it supplies the development roller  17  with the toner, by its stirring portion  12   c . In other words, the rotational member  12  doubles as a toner stirring member, making it unnecessary to provide the toner container  11  with a member dedicated to the stirring of the toner. That is, this embodiment of the present invention makes it easier to assembly a thin toner container than the preceding embodiment of the present invention. 
     While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims. 
     This application claims priority from Japanese Patent Applications Nos. 2010-291708 and 2011-249456 filed Dec. 28, 2010 and Nov. 15, 2011 which are hereby incorporated by reference.