Abstract:
A cleaning device includes a cleaning blade for removing toner remaining on a surface of an image bearing member for carrying a toner image; a supporting member for supporting the cleaning blade; a mounting hole provided in one of the cleaning blade and the supporting member; a projection which is provided on the other of the cleaning blade and the supporting member and which is inserted in the mounting hole; and a recess provided in the projection and extended from a free end portion of the projection toward a base portion of the projection, wherein the cleaning blade and the supporting member are secured to each other by the projection deformed such that the recess expands outwardly of the mounting hole by resin material in the recess.

Description:
This application is a divisional of U.S. patent application Ser. No. 12/711,500, filed Feb. 24, 2010, now U.S. Pat. No. 8,073,377. 
    
    
     FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to a cleaning device, a developing device, a cartridge, a method for securing a cleaning blade, and a method for securing a development blade. 
     Here, a cleaning device (cleaning blade), and a developing device (development blade) are such apparatuses that are used in an electrophotographic image forming apparatus. 
     Further, an electrophotographic image forming apparatus is an apparatus for forming an image on a recording medium with the use of an electrophotographic image formation process. It includes an electrophotographic copying machine, an electrophotographic printer (LED printer, laser beam printer, etc., for example), an electrophotographic facsimile apparatus, an electrophotographic word processor, and the like. 
     Further, a cartridge means a process cartridge which contains a minimum of a developing means placed in the cartridge (shell) to make the developing means removably mountable in the main assembly of an image forming apparatus, or a process cartridge which contains an image bearing member, and a cleaning means for removing the developer on the peripheral surface of the image bearing member, which are integrally placed in the cartridge (shell) to make them removably mountable in the main assembly of an image forming apparatus. 
     Conventionally, a piece of metallic plate which supports a cleaning blade for removing the developer (which hereafter will be referred to as “toner”), or a piece of metallic plate which supports a developer regulating member for regulating the toner on a developer bearing member, are attached with the use of screws (Japanese Laid-open Patent Application 2003-177644; FIGS. 9 and 10). 
     However, using screws to attach the metallic plate sometimes creates the following problems. That is, when manufacturing metallic screws, some screws come out with tiny pieces of metal of which the screws are made of, or tiny pieces of metal with which the screws are plated. These tiny pieces of metal remain attached to the screws. Further, when manufacturing resin screws, some screws come out with tiny pieces of resin, and these tiny pieces of resin remain attached to the screws. Further, some of these screws are shipped out in a bundle. Thus, the screws rub against each other during shipping, and therefore, some of the tiny metallic or resin pieces sometimes become separated from the screws. Further, as these screws having tiny metallic or resin pieces are tightened, the tiny metallic or resin pieces sometimes separate from the screws as they come into contact with the screw driver. Moreover, some of the tiny pieces of metal or resin having separated from the screws fall into a process cartridge. This creates problems. That is, in the case of some process cartridges, their photosensitive drums, charge rollers, development rollers, etc., are disposed below where the abovementioned screws are attached, because of the structure of the process cartridges. Thus, it is possible that the separated tiny pieces of metal or resin will adhere to the photosensitive drums, charge rollers, development rollers, etc. Thus, a process for cleaning each cartridge, and/or a process for examining each cartridge, becomes necessary. Besides, in recent years, a required level of image quality has become higher and higher. Thus, in order to achieve the higher level of image quality, the cleaning process and/or the examining process has to be more rigidly carried out. Also in recent years, process cartridges have been substantially reduced in size, making it necessary to reduce in size the metallic plate for supporting the cleaning blade and developer regulating member. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a cleaning device, a developing device, and a cartridge, to which a blade can be easily attached, and a blade attaching method which is easier than any of the conventional blade attaching methods. 
     According to an aspect of the present invention, there is provided a cleaning device comprising a cleaning blade for removing toner remaining on a surface of an image bearing member for carrying a toner image; a supporting member for supporting said cleaning blade; a mounting hole provided in one of said cleaning blade and said supporting member; 
     a projection which is provided on the other of said cleaning blade and said supporting member and which is inserted in said mounting hole; and a recess provided in said projection and extended from a free end portion of said projection toward a base portion of said projection, wherein said cleaning blade and said supporting member are secured to each other by said projection deformed such that said recess expands outwardly of said mounting hole by resin material in said recess. 
     According to another aspect of the present invention, there is provided a developing device comprising a developing blade for regulating toner to be applied on a developing roller; a supporting member for supporting said developing blade; a mounting hole provided in one of said developing blade and said supporting member; a projection which is provided on the other of said developing blade and said supporting member and which is inserted in said mounting hole; and a recess provided in said projection and extended from a free end portion of said projection toward a base portion of said projection, wherein said developing blade and said supporting member are secured to each other by said projection deformed such that said recess expands outwardly of said mounting hole by resin material in said recess. 
     According to a further aspect of the present invention, there is provided a cleaning blade securing method for securing a cleaning blade for a cleaning device, wherein said cleaning blade is effective to remove toner remaining on a surface of an image bearing member for carrying a toner image, and said cleaning device includes a supporting member for supporting said cleaning blade; a mounting hole provided in one of said cleaning blade and said supporting member; a projection which is provided on the other of said cleaning blade and said supporting member and which is inserted in said mounting hole; a recess provided in said projection and extended from a free end portion of said projection toward a base portion of said projection, said method comprising steps of inserting said projection into said mounting hole; injecting molten resin material into said recess to deform said projection so as to expand said recess outwardly of said mounting hole by a pressure of the resin material; and curing the resin material to secure said cleaning blade to said supporting member. 
     According to a further aspect of the present invention, there is provided a developing blade securing method for securing a developing blade for a developing device, wherein said developing blade is effective to regulate toner to be applied on a developing roller, and said developing device includes a supporting member for supporting said developing blade; a mounting hole provided in one of said developing blade and said supporting member; a projection which is provided on the other of said developing blade and said supporting member and which is inserted in said mounting hole; a recess provided in said projection and extended from a free end portion of said projection toward a base portion of said projection, said method comprising inserting said projection into said mounting hole; injecting molten resin material into said recess to deform said projection so as to expand said recess outwardly of said mounting hole by a pressure of the resin material; and curing the resin material to secure said developing blade to said supporting member. 
     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 a sectional view of the process cartridge in the first preferred embodiment of the present invention, at a plane which corresponds in position to the most essential portion of the process cartridge. 
         FIG. 2  is a sectional view of the image forming apparatus in the first preferred embodiment of the present invention, at a plane which corresponds in position to the most essential portion of the image forming apparatus. 
         FIG. 3  is a sectional view of the cleaning unit in the first preferred embodiment of the present invention. 
         FIG. 4(   a ) is a drawing which shows the general structure of a conventional cleaning unit, and  FIG. 4(   b ) is a drawing which shows the general structure of the cleaning unit in the first preferred embodiment. 
         FIG. 5(   a ) is a top plan view of the one of the bosses of the cleaning unit frame in the first preferred embodiment of the present invention, and  FIG. 5(   b ) is a perspective view of one of the bosses of the cleaning unit frame in the first preferred embodiment of the present invention. 
         FIG. 6(   a ) is a schematic sectional view of a combination of the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, in the first preferred embodiment of the present invention, and  FIG. 6(   b ) is an enlarged sectional view of the combination of the metallic plate of the cleaning blade, cleaning unit frame, and one of the bosses of the cleaning unit frame, in the first preferred embodiment of the present invention. 
         FIG. 7(   a ) is a schematic sectional view of the jig for attaching the metallic plate of the cleaning blade, the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, prior to the resin injection, in the first preferred embodiment. It shows the state of connection between the metallic plate and cleaning unit frame.  FIG. 7(   b ) is a schematic sectional view of the jig for attaching the metallic plate of the cleaning blade, the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, during the resin injection, in the first preferred embodiment. It shows the state of connection between the metallic plate and cleaning unit frame.  FIG. 7(   c ) is a schematic sectional view of the jig for attaching the metallic plate of the cleaning blade, the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, after the resin injection, in the first preferred embodiment. It shows the state of connection between the metallic plate and cleaning unit frame. 
         FIG. 8(   a ) is a perspective view of a combination of the solidified body of resin, one of the bosses of the cleaning unit frame, the metallic plate of the cleaning blade, and the cleaning unit frame, after the completion of the process of attaching the metallic plate to the cleaning unit frame, in the first preferred embodiment of the present invention, and  FIG. 8(   b ) is a sectional view of the combination of the solidified body of resin, one of the bosses of the cleaning unit frame, the metallic plate of the cleaning blade, and the cleaning unit frame, after the completion of the process of attaching the metallic plate to the boss of the cleaning unit frame, in the first preferred embodiment of the present invention. 
         FIG. 9(   a ) is top plan view of one of the bosses of the cleaning unit frame in the second preferred embodiment of the present invention, and  FIG. 9(   b ) is a perspective view of one of the bosses of the cleaning unit frame in the second preferred embodiment of the present invention. 
         FIG. 10(   a ) is a schematic sectional view of a combination of the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, in the second preferred embodiment of the present invention, and  FIG. 10(   b ) is a sectional view, including a partial enlargement, of the combination of the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, in the second preferred embodiment of the present invention. 
         FIG. 11(   a ) is a schematic sectional view of the jig for attaching the metallic plate of the cleaning blade, the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, prior to the resin injection, in the second preferred embodiment. It shows the state of connection between the metallic plate and cleaning unit frame.  FIG. 11(   b ) is a schematic sectional view of the jig for attaching the metallic plate of the cleaning blade, the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, during the resin injection, in the second preferred embodiment. It shows the state of connection between the metallic plate and cleaning unit frame.  FIG. 11(   c ) is a schematic sectional view of the jig for attaching the metallic plate of the cleaning blade, the metallic plate of the cleaning blade, the cleaning unit frame, and one of the bosses of the cleaning unit frame, after the resin injection, in the second preferred embodiment. It shows the state of connection between the metallic plate and cleaning unit frame. 
         FIG. 12(   a ) is a perspective view of a combination of the solidified body of resin, one of the bosses of the cleaning unit frame, the metallic plate of the cleaning blade, and the cleaning unit frame, after the completion of the process of attaching the metallic plate to the cleaning unit frame, in the second preferred embodiment of the present invention, and  FIG. 12(   b ) is a sectional view, including an enlarge view, of the combination of the solidified body of resin, one of the bosses of the cleaning unit frame, the metallic plate of the cleaning blade, and the cleaning unit frame, after the completion of the process of attaching the metallic plate to the cleaning unit frame the boss, in the second preferred embodiment of the present invention. 
         FIG. 13(   a ) is a top plan view of one of the bosses of the cleaning unit frame, which is made up of two equal pieces (halves), in the third preferred embodiment of the present invention, and  FIG. 13(   b ) is a top plan view of one of the bosses of the cleaning unit frame, which is made up of six equal pieces. 
         FIG. 14(   a ) is a top plan view of the boss in the fourth preferred embodiment of the present invention, and  FIG. 14(   b ) is a side view of the boss in the fourth preferred embodiment of the present invention. 
         FIG. 15(   a ) is a top plan view of one of the bosses of the cleaning unit frame in the fifth preferred embodiment of the present invention, and  FIG. 15(   b ) is a side view of the boss in  FIG. 15(   a ), in the fifth preferred embodiment of the present invention. 
         FIG. 16(   a ) is a perspective view of a combination of the solidified resin, one of the bosses of the development unit frame, the metallic plate of the development blade, and the development unit frame, in the sixth preferred embodiment of the present invention, and  FIG. 16(   b ) is a sectional view of the combination in  FIG. 16(   a ), in the sixth preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
     Overall Structure of Image Forming Apparatus 
       FIG. 1  is a sectional view of the process cartridge, in the first preferred embodiment of the present invention, which has a development unit to which the present invention is applicable, at a plane which corresponds in position to the essential portion of the process cartridge.  FIG. 2  is a sectional view of the image forming apparatus, in the first preferred embodiment of the present invention, to which the present invention is applicable, at a plane which corresponds in position to the essential portion of the image forming apparatus. The process cartridge in this embodiment is provided with an image bearing apparatus, and a processing means which processes the image bearing member. The cartridge is removably mountable in the image forming apparatus in  FIG. 2 . As the processing means, there are a charging means for charging the peripheral surface of the image bearing member, a developing device for forming an image on the image bearing member, and a cleaning device for removing the toner remaining on the peripheral surface of the image bearing member, for example. 
     Referring to  FIG. 1 , a process cartridge  15  has a photosensitive drum  11  and a charge roller  12 . The photosensitive drum  11  holds a toner image. The charge roller  12  is a charging means, and is in the adjacencies of the peripheral surface of the photosensitive drum  11 . The process cartridge  15  has also a development unit D (developing device), which has a development roller  18 , a development blade  19 , and a toner storage container  16  in which toner is stored. The process cartridge  15  has also an elastic cleaning blade  14  as a cleaning means. Further, the process cartridge  15  has a housing in which the abovementioned components are integrally held. It is removably mountable in the main assembly C of the image forming apparatus. 
     From a sheet cassette  6  mounted in the bottom portion of the main assembly C of the image forming apparatus, a sheet S of recording medium is conveyed into the main assembly C by a sheet conveyance roller  7 . In synchronism with this conveyance of the sheet S, a latent image is formed on the peripheral surface of the photosensitive drum  11  by selectively exposing the numerous points of the peripheral surface of the photosensitive drum  11  with an exposing apparatus  8 . Meanwhile, the toner in a toner storage container  16  is coated in a thin layer on the peripheral surface of the development roller  18  by the development blade  19  held by development unit frame  17 . The toner is two-component toner, that is, a mixture of magnetic toner and magnetic carrier. The development blade  19  regulates the manner in which the toner is coated on the peripheral surface of the development roller  18 . Then, the latent image is supplied (developed) with the toner by applying development bias to the development roller  18  as a developer bearing member. As a result, a visible image is formed on the peripheral surface of the photosensitive drum  11 . Then, the toner image is transferred by the application of bias voltage to a transfer roller  9 , from the photosensitive drum  11  onto the sheet S, which is being conveyed. Then, the sheet S is conveyed to a fixing apparatus  10 , in which the toner image is fixed to the sheet S. Then, the sheet S is discharged by two pairs of discharge rollers  1  into a developer tray  3 , which is a part of the top portion of the apparatus main assembly. 
     [Structure of Cleaning Unit] 
     Next, referring to  FIGS. 3 and 4 , the structure of the cleaning unit will be described in detail.  FIG. 3  is a sectional view of the cleaning unit, and  FIG. 4(   b ) is a front view of the cleaning unit.  FIG. 4(   a ) is a front view of a conventional cleaning unit, and is provided for comparison. 
     As will be evident from  FIGS. 3 and 4(   b ), the cleaning blade  14  is made up of a metallic plate  14   a  and a rubber portion  14   b . The metallic plate  14   a  is solidly attached to the frame of the cleaning unit. The rubber portion  14   b  is attached to the metallic plate  14   a . The material for the rubber portion  14   b  is polyurethane. The rubber portion  14   b  is in contact with the peripheral surface of the photosensitive drum  11 . Thus, as the photosensitive drum  11  rotates in the direction indicated by an arrow mark A in  FIG. 3 , the rubber portion  14  removes the toner on the peripheral surface of the photosensitive drum  11 . The removed toner is accumulated in a waste toner chamber  13   a . The cleaning unit has an elastic sheet  23 , which is pasted on the sheet supporting surface  13   b  of the cleaning unit frame  13 . Thus, the toner remaining on the peripheral surface of the photosensitive drum  11  after the transfer of the toner image is guided into the waste toner chamber  13   a  by the elastic sheet  23 . The elastic sheet  23  is kept lightly pressed upon the peripheral surface of the photosensitive drum  11  just enough to prevent the residual toner in the waste toner chamber  13   a  from passing between the sheet  23  and peripheral surface of the photosensitive drum  11 . 
     [Solid Attachment of Cleaning Blade] 
     Next, the method for solidly attaching the cleaning blade  14  will be described. Conventionally, the cleaning blade  14  is attached to the cleaning unit frame  13  as shown in  FIG. 4(   a ). That is, the cleaning blade  14  is precisely positioned relative to the cleaning unit frame  13  by engaging the cleaning blade positioning portion  25 , with which the metallic plate  14   a  of the cleaning blade  14  is provided, with the cleaning blade positioning portion  24  of the cleaning unit frame  13 . The cleaning blade positioning portion  24  of the cleaning unit frame  13  is a boss which is rectangular in cross section, whereas the cleaning blade positioning portion  25  of the cleaning blade  14  is a recess with which the metallic plate  14   a  of the cleaning blade  14  is provided. Thus, as these two cleaning blade positioning portions  24  and  25  engage with each other, the cleaning blade  14  is precisely positioned relative to the cleaning unit frame  13 . Incidentally, in the case of some cleaning units, the cleaning blade  14  is precisely positioned by a combination of a round boss, and a round recess (unshown). The cleaning blade  14  is attached to the cleaning unit frame  13  by putting screws  26  through through holes of the metallic plate  14   a , and a blind holes or through holes of the cleaning unit  13 , and tightening the screws  26 . Next, referring to  FIGS. 4(   b ) and  8 , in the case of the cleaning unit in this embodiment, the metallic plate  14   a  of the cleaning blade  14  is provided with the through holes  14   c  (blade attachment holes), whereas the cleaning unit frame  13  is provided with bosses  27 . Thus, the cleaning blade  14  is attached to the cleaning unit frame  13  by positioning the cleaning blade  14  so that the bosses  27  fit in the holes  14   c  of the cleaning blade  14 , and then, applying resin. 
     Next, the attachment of the cleaning blade  14  to the cleaning unit frame  13 , to which the cleaning blade  14  is to be attached, in this preferred embodiment of the present invention, will be described in detail.  FIGS. 5(   a ) and  5 ( b ) show one of the bosses for attaching the cleaning blade  14  to the cleaning unit frame  13 .  FIG. 6(   a ) shows the metallic plate  14   a  and one of the bosses (protrusions) of the cleaning unit frame  13 , in this embodiment, prior to the attachment of the cleaning blade  14 .  FIG. 5(   a ) is a top plan view of the boss  27 , and  FIG. 5(   b ) is a perspective view of the boss  27 .  FIG. 6(   a ) is a sectional view of the metallic plate  14   a  and boss  27 , at a plane indicated in  FIG. 5(   a ) by a single-dot chain line.  FIG. 6(   b ) is a sectional view of the metallic plate  14   a  and boss  27  when the boss  27  is in the hole  14   c  of the metallic plate  14   a.    
     The metallic plate  14   a  of the cleaning blade  14  has the cleaning blade attachment holes  14   c . The cleaning unit frame  13  has the bosses  27 , with which the metallic plate  14   a  is solidly attached to the cleaning unit frame  13 . Each boss  27  is cylindrical and hollow. That is, the end portion of the boss  27  is a cylindrical blind hole, which extends inward from the tip of the boss  27 . The cylindrical wall of the boss  27  is thinner than the wall of the main structure of the cleaning unit frame  13 . The metallic plate  14   a  is placed on the cleaning unit frame  13  so that the bosses  27  come through the cleaning blade attachment holes  14   c , one for one ( FIG. 6 ), with the presence of a minute gap  30  between each boss  27  and the wall of the corresponding hole  14   c , because the boss  27  is slightly smaller in cross section than the hole  14   c  ( FIG. 6(   b ); enlarged view). Next, an resin injection jig  28  is placed on the metallic plate  14   a  so that the boss  27  and hole  14   c  are covered with the jig  28 , as shown in  FIG. 7(   a ). The resin injection jig  28  has a resin injection hole  28   a , which is in the middle of the top wall of the jig  28 , and through which melted resin  29  is injected inward of the jig  28 . It also has a space in which the boss  27  and hole  14   c  will be as the jig  28  is placed on the metallic plate  14   a . The melted resin  29  is injected inward of the jig  28  through the abovementioned center hole  28   a . Since the melted resin  29  (which will cool down and become solid resin  29  after injection) is injected through the center hole  28   a , the melted resin  29  flows into the adjacencies of the center portion F (portion covered with dots) of the boss  27  ( FIG. 7(   b )). The wall of the boss  27  is thin as described above. Therefore, as the melted resin  29  is injected, the boss  27  outwardly deforms because of the pressure from the melted resin  29 . Then, the injected melted resin  29  flows into an area G, which is the outward adjacency of the boss  27 , through a gap H which is between the top of the boss  27  and the inward surface of the jig  28 , and fills the abovementioned internal space of the jig  28  ( FIG. 7(   c )). Then, the jig  28  is moved away, ending thereby the process of attaching the metallic plate  14   a  to the cleaning unit frame  13  ( FIGS. 8(   a ),  8 ( b ), and  8 ( c )). As the injected melted resin  29  fills the center hole of the boss  27 , surrounds the adjacencies of the hole  14   c  of the metallic plate  14   a , and solidifies, the metallic plate  14   a  becomes solidly attached to the cleaning unit frame  13 . Further, as the melted resin  29  is injected, the bottom portion of the wall of the boss  27  is expanded as wide as the diameter of the hole  14   c  of the metallic plate  14   a  by the pressure from the injected melted resin  29  as described above. Thus, the metallic plate  14   a  is precisely positioned in terms of the diameter direction of the hole  14   c  of the metallic plate  14  as well ( FIG. 8(   b ); enlarged view). 
     In this embodiment, the metallic plate  14   a  is solidly attached to the cleaning unit frame  13  with the use of resin, making it possible to eliminate the screws which have been used in the case of the conventional method for attaching the metallic plate  14   a . Therefore, the abovementioned metallic nuisance (tiny pieces of metal) which might result from the usage of the screws does not occur. Further, the two portions, that is, the positioning portion and attachment portion, which the conventional method for attaching the cleaning blade to the cleaning unit frame require, do not need to be separately provided. That is, in the case of the cleaning blade attaching method in this embodiment, both the metallic plate positioning function and metallic plate attaching function are provided by the same combination of components (boss and corresponding hole), making it possible to reduce the cleaning unit in size, and also, affording more latitude when designing an image forming apparatus (cleaning unit). 
     Incidentally, in this preferred embodiment, the cleaning unit frame  13  is provided with the bosses  27 , and the cleaning blade  14  is provided with the blade attachment hole  14   c . Instead, however, the cleaning unit frame  13  may be provided with the blade attachment holes, and the cleaning blade  14  may be provided with the cleaning blade attachment bosses. That is, all that is necessary is that one of the cleaning blade  14  and cleaning unit frame  13  is provided with the holes  14   c , and the other is provided with the bosses. 
     Embodiment 2 
     Shown in  FIGS. 9(   a ) and  9 ( b ) is another preferred embodiment of the present invention. In this preferred embodiment, each of the bosses  127  has four vertical slits which are distributed with even intervals in the circumferential direction of the boss  127 . Each slit extends from the tip of the boss  127  to the bottom of the boss  127 . In other words, the boss  127  has a cylindrical central hole  14   c , which is similar to the cylindrical central hole  14   c  of the boss  27  in the first preferred embodiment, and four slits (gaps) which extend from the center hole  14   c  to the peripheral surface of the boss  127 . 
     First, the metallic plate  14   a  is placed against the cleaning unit frame  13  so that each boss  127  fits in the corresponding hole  14   c  of the metallic plate  14   a  ( FIGS. 10(   a ) and  10 ( b )). Incidentally, the boss  127  is slightly smaller in diameter than the hole  14   c . Thus, as the boss  127  fits in the hole  14   c , a small gap  30  remains between the peripheral surface of the boss  127  and the inward surface of the hole  14   c  of the metallic plate  14   a  ( FIG. 10(   b ); enlarged view). 
     Next, the resin injection jig  28  is placed on the metallic plate  14   a  so that the boss  127  and hole  14   c  are covered with the jig  28 , as shown in  FIG. 11(   a ). The resin injection jig  28  has a resin injection hole  28   a , which is in the middle of the top wall of the jig  28 , and through which melted resin  29  is injected inward of the jig  28 . The jig  28  has also a space in which the boss  127  and hole  14   c  will be as the jig  28  is placed on the metallic plate  14   a . The melted resin  29  is injected inward of the jig  28  through the abovementioned center hole  28   a . Since the melted resin  29  (which will cool down and become solid resin  29  after injection) is injected through the center hole  28   a , the melted resin  29  flows into the adjacencies of the center portion F (portion covered with dots) of the boss  127  ( FIG. 11(   b )). As the melted resin  29  is injected, the boss  127  outwardly deforms by being pressed outward by the pressure from the melted resin  29 . Then, the injected melted resin  29  flows into the area G, which is the outward adjacency of the peripheral surface of the boss  127 , through the slits  127   a , and fills the abovementioned internal space of the jig  28  ( FIG. 11(   c )). Then, the jig  28  is moved away, ending thereby the process of attaching the metallic plate  14   a  to the cleaning unit frame  13  ( FIGS. 12(   a ) and  12 ( b )). As the injected melted resin  29  fills the center hole of the boss  127 , surrounds the adjacencies of the hole  14   c  of the metallic plate  14   a , and solidifies, the metallic plate  14   a  becomes solidly attached to the cleaning unit frame  13 . Further, as the melted resin  29  is injected, the bottom portion of the wall of the boss  127  is expanded as wide as the diameter of the hole  14   c  of the metallic plate  14   a  by the pressure from the injected melted resin  29  as described above. Thus, the metallic plate  14   a  is precisely positioned in terms of the diameter direction of the hole  14   c  of the metallic plate  14   a  as well ( FIG. 12(   b ); enlarged view). In other words, the second preferred embodiment can provide the same effects as those provided by the first preferred embodiment. In addition, the boss  127  in this embodiment is provided with the slits  127   a . Therefore, it more easily deforms during the injection of the resin  29 . In this embodiment, therefore, even if the pressure generated by the injection of the resin  29  is lower, the metallic plate  14   a  is precisely positioned relative to the cleaning unit frame  13 . 
     Embodiment 3 
     The number of pieces into which each of the bosses of the cleaning unit  13  is to be split does not need to be four as it is in the second preferred embodiment. That is, each boss may be split into two pieces ( FIG. 13(   a )) like each of the bosses  227 , or more than four pieces ( FIG. 13(   b )) like each of the bosses  327 , in this preferred embodiment. The same effects as those obtained in the first and second preferred embodiments can also be obtained even in the case where each of the bosses of the cleaning unit frame are split into two pieces, or four or more pieces. 
     Embodiment 4 
     The bosses of the cleaning unit frame may be square ( FIG. 14 ) in cross section, instead of being circular. In this embodiment, each boss is square in cross section, and has multiple (four) sections separated by multiple (four) slits  427   a . The same effects as those obtainable in the first and second preferred embodiments can also be obtained by a boss such as the boss  427  in this embodiment. 
     Embodiment 5 
     Instead of structuring each of the bosses of the cleaning unit frame as if it is split into four pieces by a cross, each boss may be made up of multiple smaller bosses like the eight smaller bosses  527   b , in this embodiment, which are roughly circularly positioned ( FIG. 15 ). The same effects as those obtainable in the first and second preferred embodiment can also be obtained even if each of the bosses of the cleaning unit frame is made up of smaller bosses like the bosses  527   b , in this embodiment, which are roughly circularly positioned. 
     Embodiment 6 
     In the preceding preferred embodiments of the present invention, the metallic plate  14   a  is solidly attached to the cleaning unit frame  13  to solidly attach the cleaning blade  14  to the cleaning unit frame  13 . However, the present invention can be applied to attach a development blade  19  to a developing device frame  17  ( FIGS. 16(   a ) and  16 ( b )). In such a case, effects similar to those obtained in the first preferred embodiment can be obtained by replacing the cleaning blade  14  and cleaning unit frame  13  with the development blade  19  and developing unit frame  17 , respectively. Further, the development blade  19  can be solidly attached to the developing unit frame  17  with the use of bosses like those in the first, second, third, fourth, and fifth preferred embodiments. 
     In this (sixth) preferred embodiment, the development unit frame  17  is provided with the bosses, and the development blade  19  is provided with the development blade attachment holes. Instead, however, it may be the development unit frame  17  and development blade  19  that are provided with the development blade attachment holes and bosses, respectively. 
     Further, the preceding preferred embodiments of the present invention were described with reference to the cartridges which are removably mountable in the main assembly of an image forming apparatus. However, the present invention is applicable also to a cleaning device or developing device which is solidly attached to the main assembly of an image forming apparatus. Further, the present invention is applicable to a cleaning device or developing device which is structured so that it is removably mountable in the main assembly of an image forming apparatus. 
     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. 046386/2009 and 286066/2009 filed Feb. 27, 2009 and Dec. 17, 2009, respectively, which are hereby incorporated by reference.