Abstract:
A seal assembly for inhibiting toner leakage comprises a j-seal received by a developer housing in a toner cartridge. The j-seal has an upper seat portion engagably sealing with a doctor blade seal and a leg for slidably sealing of a developer roll. The upper seat portion has an upper seat inner seal wall and an upper seat outer seal wall spaced apart a preselected distance from said upper seat inner seal wall and defining a gap therebetween. A doctor blade seal engages the upper seat inner and outer seal walls and a doctor blade bracket assembly disposed adjacent the j-seal and the doctor blade seal. The doctor blade seal further has a tongue disposed within the gap for interlocking said j-seal and sealably engaging the doctor blade bracket assembly.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This patent application is related to the U.S. patent application Ser. No. 11/959,058, filed even date herewith, entitled “Developer Roll Lip Seal” and assigned to the assignee of the present application. The lip seal disclosed in this related application may be used in combination with the upper seal disclosed herein but it may also be used independently of this upper seal. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     None. 
     REFERENCE TO SEQUENTIAL LISTING, ETC. 
     None. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a doctor blade assembly, and more specifically relates to an upper seal for a doctor blade assembly which inhibits toner leakage generally in the area of the developer housing and the doctor blade bracket assembly. 
     2. Description of the Related Art 
     Laser printers utilize a light beam which is focused to expose a discrete portion of a photoreceptive or image transfer drum in a further attempt to attract printing toner to these discrete portions. One component of a laser printer is the photoreceptive drum assembly. This photoreceptive drum assembly is made out of highly photoconductive material that is discharged by light photons typically embodied by a laser. Initially, the drum is given a charge by a charge roller. As the photoreceptive drum revolves, the printer shines a laser beam across the surface to discharge certain points. In this way, the laser “draws” the letters and images to be printed as a pattern of electrical charges—an electrostatic latent image. The system can also work with either a more positively charged electrostatic latent image on more negatively charged background or a more negative charged electrostatic latent image on a more positively charge background. 
     The printer&#39;s laser or laser scanning assembly draws the image to be printed on the photoreceptive drum. The traditional laser scanning assembly may include a laser, a movable mirror and a lens. The laser receives the image data defined by pixels that make up the text and images one horizontal line at a time. As the beam moves across the drum, the laser emits a pulse of light for every pixel to be printed. Typically, the laser doesn&#39;t actually move the beam. Instead, the laser reflects the light beam off of a movable mirror. As the mirror moves, the light beam passes through a series of lenses. This system compensates for the image distortion caused by the varying distance between the mirror and points along the drum. The laser assembly moves in one plane horizontally as the photoreceptor drum continuously rotates so the laser assembly can draw the next line. A print controller synchronizes this activity. The process of forming the light image on the photoreceptive drum discharges those areas where the image is formed. 
     When the toner becomes electrostatically charged, the toner is attracted to exposed portions of the image transfer drum. After the data image pattern is set, charged toner is supplied to the photoconductive drum. Because of the charge differential, the toner is attracted to and clings to the discharged areas of the drum, but not to the similarly charged “background” portions of the photoconductive drum. Toner is an electrostatically charged powder with two main ingredients, pigment and plastic. The pigment provides the coloring, such as black in a monochrome printer to form text and images. This pigment is blended with plastic particles, so the toner will melt when passing through the heat of a fuser assembly. The toner is stored in the toner cartridge housing, a small container built into a removable casing. The printer gathers the toner from a sump within the housing and supplies it to a developer unit using paddles and transfer rollers. The developer roll is a charged rotating roller, typically with a conductive metal shaft and an polymeric conductive coating, which receives toner from a toner adder roll position adjacent the developer roll. Due to electrical charge and mechanical scrubbing, the developer roll collects toner particles from the toner adder roll. A doctor blade assembly engages the developer roll to provide a consistent coating of toner along the length and surface of developer roll, by scraping or “doctoring” excess toner from the developer roll. The doctor blade may also induce a charge on the toner. In turn, this provides a consistent supply of toner to the photoconductive drum. When the coating of toner on the developer roll is inconsistent, too thick, too thin or bare, coating of the photoconductive drum is inconsistent and the level of darkness of the printed image may vary unintentionally, which is considered a print defect. 
     The electrostatic image on the photoconductive drum is charged such that the toner particles move from the developer roll onto the latent image on photoconductive drum. With the image data toner pattern on the photoconductive drum, the drum engages a sheet of paper or media moving adjacent thereto. The paper or other media is driven by a transport belt, which is oppositely charged to the toner causing it to transfer to the paper or other media. This charge is stronger than the charge of the electrostatic image, so the paper can pull the toner powder away from the surface of the photoconductive drum. When a medium, printing paper, passes beneath the rotating photoconductive drum, the toner is transferred to the medium. Since it is moving at the same speed as the drum, the paper picks up the image pattern exactly. To keep the paper from clinging to the drum, it can be discharged immediately after picking up the toner. 
     One problem with existing doctor blade assemblies is that of providing a consistent seal generally around the location where doctor blade assembly and the developer housing meet due to the tolerances and stiffness of the seal utilized in this location. Additionally, as shown in the prior art device depicted in  FIG. 7 , the corner area where the bracket and doctor blade meet also provides a leakage path. The paddles that move the toner from the sump to the developing components of the cartridge cause a cyclical internal toner pressure in the cartridge. The operational toner pressure as well as vibration and drop testing has demonstrated this corner location to be a frequent toner leak path, especially in higher volume developer housings. The leakage occurs in the area of the blade and bracket corner due to deformation of the upper portion of the j-seal when the bracket assembly is disposed thereon. 
     It would be desirable to inhibit toner leakage in the area of the corner of the developer housing as well as the corner where the bracket and blade meet without adding additional parts or increasing expense through additional components to seal this area. 
     SUMMARY OF THE INVENTION 
     A seal, for inhibiting toner leakage from a toner cartridge having a doctor blade assembly having a doctor blade seal and a developer roll, comprises an upper seat portion for sealably engaging said doctor blade assembly and a leg for sealably engaging said developer roll. The upper seat portion comprises an upper seat inner seal wall and an upper seat outer seal wall spaced apart from said upper seat inner seal wall a preselected distance and defining a gap therebetween for closely receiving a portion of the doctor blade seal between said upper seat inner and outer seal walls. In a further embodiment, the upper seat inner seal wall is disposed at a substantially acute angle respect to said upper seat outer seal wall and in another embodiment, the upper seat outer seal wall comprises an upper tapered horizontal edge and a curved vertical edge. 
     A seal assembly for inhibiting toner leakage comprises a j-seal positioned to be received by a developer housing. The j-seal has an upper seat portion forming a doctor blade seal and a leg for slidably sealing a developer roll. The upper seat portion has an upper seat inner seal wall and an upper seat outer seal wall spaced apart a preselected distance and defining a gap. The doctor blade seal engages the upper seat inner and outer seals. A doctor blade bracket assembly is disposed adjacent the j-seal and the doctor blade seal, the doctor blade seal further having a tongue disposed within the gap defined between the upper seat inner and outer seal walls, the doctor blade seal sealably engaging the doctor blade bracket assembly. The seal assembly further comprises a curved upper edge of the upper seat outer seal. The seal assembly further comprises having the upper seat inner seal angled to receive an angled surface of the doctor blade seal. The doctor blade bracket assembly compresses the doctor blade seal within the upper seat portion of the j-seal. The doctor blade bracket assembly engages an upper curved or tapered edge of the upper outer seat seal to provide an inwardly directed component force on the upper seat outer seat. The doctor blade seal further comprises an edge rib on an end surface. 
     The seal assembly for inhibiting toner leak comprises a j-seal having a lower j-shaped portion for receiving and slidably sealing a roll and an upper seat portion, the upper seat portion has a first upper seat seal, a second upper seat seal and a gap defined between the first upper seat seal and the second upper seat seal, a doctor blade seal has a tongue disposed at ends of the doctor blade seal, the tongue positioned between the first upper seat seal and the second upper seat seal and interlocking the j-seal and the doctor blade seal, the doctor blade seal sealing along three edges of the j-seal, a doctor blade assembly disposed on the doctor blade seal so that the doctor blade engages the first upper seat seal, the second upper seat seal, the upper seat portion of said j-seal and the doctor blade seal. The doctor blade assembly includes at least one bracket and a doctor blade. The first upper seat seal is an upper seat inner seal. The upper seat inner seal is disposed at an angle from a front surface of the j-seal. The second upper seat seal is an upper seat outer seal. An upper edge of the upper seat outer seal is curved tapered to provide an inwardly directed component force on the second upper seat seal to improve sealing. The seal assembly further comprises a recess defined by at least two surfaces of the doctor blade seal, the recess receiving the upper seat inner seal of the j-seal. 
     A seal assembly for preventing toner leakage comprises a first j-seal having a first upper seat portion, a second j-seal having a second upper seat portion, a doctor blade seal extending between the first j-seal and the second j-seal, ends of the doctor blade seal disposed within the respective first upper seat portion and the second upper seat portion, each of the first and second upper seat portions having a upper seat inner seal and an upper seat outer seal, a gap defined between each of the upper seat inner and outer seals, the doctor blade seal having a tongue disposed within each respective gap interlocking the first and second j-seals with the doctor blade seal, the tongue sealing within a corner defined by a doctor blade and the doctor blade bracket. The seal assembly further comprises an upper tapered edge on each of the upper seat outer seal. The seal assembly further comprises the upper seat inner seal is disposed at an acute with respect to the upper seat outer seal. The seal assembly further comprises a doctor blade assembly. The doctor blade assembly captures the doctor blade seal within the first and second seat portions of the j-seals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  depicts an exemplary electrophotographic printer; 
         FIG. 2  depicts a partially exploded perspective view of a developer assembly; 
         FIG. 3  depicts an exploded perspective view of a developer seal assembly from a first angle; 
         FIG. 4  depicts an exploded perspective view of the developer seal from a second angle; 
         FIG. 5  depicts one end of a partially assembled toner seal assembly; 
         FIG. 6  depicts one end of the toner seal assembly; and, 
         FIG. 7  depicts a prior art seal assembly which allows some leakage around the housing, j-seal and blade assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and drawings illustrate embodiments of the invention sufficiently to enable those skilled in the art to practice it. It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. For example, other embodiments may incorporate structural, chronological, electrical, process, and other changes. Examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of the invention encompasses the appended claims and all available equivalents. The following description is, therefore, not to be taken in a limited sense, and the scope of the present invention as defined by the appended claims. 
     Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings. 
     In addition, it should be understood that embodiments of the invention include both hardware and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software. As such, it should be noted that a plurality of hardware and software-based devices, as well as a plurality of different structural components may be utilized to implement the invention. Furthermore, and as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention and that other alternative mechanical configurations are possible. 
     The term image as used herein encompasses any printed or digital form of text, graphic, or combination thereof. The term output as used herein encompasses output from any printing device such as color and black-and-white copiers, color and black-and-white printers, and so-called “all-in-one devices” that incorporate two or more functions such as scanning, copying, printing, and faxing capabilities in one device. Such printing devices may utilize ink jet, dot matrix, dye sublimation, laser, and any other suitable print formats. The term button as used herein means any component, whether a physical component or graphic user interface icon, that is engaged to initiate output. The term media and paper may be used interchangeably herein and may include plain paper, glossy photo paper, coated paper, card stock, index cards, labels, envelopes, transparency, MYLAR, fabric, or other printable materials. The term operations panel, as used herein, means an interactive display allowing for menu display, menu selections, image viewing, editing of images, correction of error conditions and other operations and control functions. The term peripheral may include a single function or multi-function, or all-in-one, device which may be connected to a host computer, network connected or may be a stand-alone, which is a device which may function independently of any host computer. 
     The exemplary embodiments described herein provide a seal assembly which inhibits toner leakage from around the area of the developer housing and the doctor blade assembly at ends of the developer roll. 
     Referring now to  FIG. 1 , a perspective view of a peripheral  10  having a laser printing mechanism is depicted in perspective view. Although, the peripheral device is depicted, one skilled in the art should realize that the present design may alternatively be used with an all-in-one device, copier, fax, stand-along device or the like having an electrophotographic (laser) print engine. The exemplary peripheral embodied by the laser printer  10 , comprises a housing  12  including a primary access door  14  positioned on the top-front of the housing  12 . The housing  12  generally comprises a front surface, first and second side surfaces, a rear surface (not shown) and a bottom surface to enclose the laser printer operating mechanisms. On the front of the housing  12 , the primary access door  14  is pivotally mounted to allow opening and access for installation or removal of a developer assembly  40  ( FIG. 2 ). The front panel of the primary access door  14  comprises an operations panel  16  which includes a display  18 , an alpha numeric keypad  20 , a plurality of selection buttons  22 , as well as a flash memory slot  24 . The operations panel  16  is in electronic communication with a controller (not shown), which may be embodied by one or more micro-processors, in order to operate the laser printer  10 . Beneath the primary access door  14  is a secondary access door  26  which allows access to the developers or toner cartridges. The printer  10  may operate in both monochrome and color. For example, three additional toner cartridges may be utilized to provide the color printing comprising the toner colors cyan, yellow or magenta, although other colors may be utilized. 
     Beneath the access doors  14 ,  26  is an input tray access door  30 . When the input tray access door  30  is opened with a release  32 , an input tray (not shown) is accessible to load the printer  10  with media. The input tray may hold a stack of media for printing and further defines a starting point of a media feedpath (not shown) extending from the media input tray to a media output tray  36 . The media feedpath may be a duplex feedpath or a simplex feedpath. The media output tray  36  is located on top of the housing  12  and generally extends rearwardly to store printed media processed by the laser printer  10 . 
     Referring now to  FIG. 2 , a developer assembly  40  is depicted in perspective view. The developer assembly  40  comprises a housing  42 , formed of a first housing portion  44  and a second housing portion  46 . Along at least one side of the housing  42  is a lid  43 . Within the first housing portion  44 , a plurality of toner is stored, and at least one paddle is located therein on a rotating shaft to move the toner from the first housing portion  44  toward the second housing portion  46 . A toner adder roll  56  is located within or adjacent to the second housing portion  46 , and receives toner there from. The toner adder roll  56  coats the developer roll D with toner, which is scraped or “doctored” by the doctor blade  54  to form an even layer of toner on the developer roll D, and in turn supplies toner to the imaging or photoreceptive drum. The seal assembly of the present embodiment inhibits leakage of toner in between the developer housing  46  and the corner  59  formed by the doctor blade bracket  52  and the doctor blade  54  when it is dropped and also during operation when the developer unit  42  vibrates and creates internal pressures. 
     The developer assembly  40  comprises seals  70  at ends of the developer roll D. The developer roll D is exploded for clarity, so that the seals  70  may be seen. The seals  70  are substantially j-shaped to receive the developer roll, although other curvilinear shapes may be utilized. The upper portion of the j-seal  70  is slightly curved to substantially match the deflected shape of a blade  54 . The lower portion of the j-seal  70  is curved to receive the developer roll D. Disposed above the seals  70  is a doctor blade seal  60 , which extends in a length that is parallel to the axial dimension of the developer roll. Also disposed above the seals  70  is a doctor blade bracket assembly  50  comprising at least one first bracket  52  and a doctor blade  54 . Like the doctor blade seal  60 , the doctor blade bracket assembly  50  also extends in a direction which is substantially parallel to the axial dimension of both the toner adder roll  56  and developer roll D. The doctor blade seal  60  is captured between the doctor blade bracket assembly  50  and the j-seal  70  or the lid  43 . The doctor blade  54  engages a developer roll to scrape excess toner from the surface of the developer roll, which provides a consistent level of toner to the imaging or photoreceptive drum of the printer  10 . The doctor blade seal  60  is seated on the j-seals  70  to inhibit leakage of toner near ends of the developer roll and between the lid  43  and the developer housing  42 . The doctor blade bracket assembly  50  compresses the doctor blade seal  60  to improve sealing in this area. 
     Referring now to  FIG. 3 , an exploded perspective view of the seal assembly  38  is depicted. The doctor blade bracket assembly  50  and the doctor blade seal  60  are cut in section for purpose of clarity. As previously indicated, the doctor blade bracket assembly  50  is disposed above the doctor blade seal  60  which is positioned above the j-seal  70 . The doctor blade bracket assembly  50  comprises a bracket  52  and a blade  54  connected to the bracket  52 . According to the exemplary embodiment, the blade  54  is welded to the bracket  52 . However the bracket  52  may be connected to the blade  54  by a fixative such as epoxy, cement, glue or the like. In a further alternative, the blade  54  may be connected to the bracket  52  by a fastener or, the blade  54  may be captured or sandwiched between first and second bracket members. The bracket  52  includes an aperture  58  for connection of the doctor blade bracket assembly  50  to the housing  42 . The aperture  58  is oval in shape so as to provide an adjustment for the blade  54  toward or away from the developer roll D. The bracket  52  is generally a stiff material such as steel and rectangular in shape extending from one side of the housing  42  to an opposed side of the housing  42 . The bottom surface of the bracket  52  is generally smooth so as to engage the upper surface of the doctor blade seal  60 . 
     The blade  54  extends from the bracket  52  toward a peripheral surface of the developer roll D in order to scrape excess toner from the outer surface of the developer roll D. The blade  54  is generally rectangular in shape having a long or width-wise dimension substantially parallel to the direction of the axial dimension of the developer roll. The blade  54  includes a front surface  55  and a rear surface  57 . The blade  54  is straight in its natural state, but in order to provide a “doctoring” force on the developer roll D has a slight curvature due to interference with the developer roll D upon installation. In addition, the blade  54  has notches near ends of the blade for removing all toner from the ends of the developer roll D where printing does not occur. The blade  54  may also receive an electrical potential in order to charge the developer roll D with a desired polarity during operation. The lower surface of the bracket  52  engages an upper surface  62  of the doctor blade seal  60 , so as to capture the seal  60  between the doctor blade assembly  50  and the j-seal  70 . According to the exemplary embodiment, the blade  54  may be formed of phosphor bronze to provide the desired elasticity and electrical conductivity or alternatively may be formed of a hardened stainless steel to provide a desired elasticity and also withstand corrosion which might damage the developer roll. Other materials may also be utilized. 
     An end portion  61  of the doctor blade seal  60  is shown above one of the j-seals  70 . The doctor blade seal  60  has first and second ends  61  ( FIG. 2 ). As previously described, the doctor blade seal  60  extends between the ends  61  in a direction generally parallel to the axial dimension of the developer roll and the toner adder roll  56 . The doctor blade seal  60  is formed of a foam material to act as a deformable seal between the bracket assembly  50  and the j-seal  70  or the lid  43 , as well as around the housing  42  adjacent the j-seal  70  and between the bracket  52  and blade  54 . The ends  61  are positioned on an upper seat surface  73  of the j-seal  70 . The portion of the doctor blade seal  60  between the ends  61  is supported by the lid  43  of the housing  42  ( FIG. 2 ). 
     The doctor blade seal  60  has an upper surface  62 , a lower surface  63  and a plurality of sides extending between the upper and lower surfaces  62 , 63 . Along the front of the doctor blade seal  60 , toward the doctor blade  54 , a tongue  64  is integrally formed with and extending from the doctor blade seal end  61 . On an outer side of the tongue  64  is an end surface  65  ( FIG. 4 ) of the doctor blade seal  60 . On the opposite surface of the tongue  64  near the blade  54 , is a tongue extending surface  66 . Angled from the tongue extending surface  66  is an angled or tapered surface  68 . The angled surface  68  joins the tongue extending surface  66  and a front seal surface  69 , which extends the distance of the doctor blade seal  60  to the opposite end  61  (not shown) of the doctor blade seal  60 . Therefore, the tongue  64  generally extends from the angled surface  68  in a direction substantially perpendicular to the front seal surface  69 . In combination, the surfaces  69 ,  68 ,  66  define a recess wherein an upper seat inner seal wall  78  of the J-seal  70  is received. As previously indicated, the doctor blade seal  60  extends in a width-wise direction, which corresponds to the width of a media sheet, and perpendicular to the media feed path direction to an opposite end of seal  60  (not shown). 
     Beneath the doctor blade seal  60 , the j-seal  70  comprises an upper seat portion  72 , and a developer roll leg  74 , which is substantially j-shaped and depending from the upper seat portion  72 . The j-seal  70  may be formed in a molding process, such as injection molding, compression molding, or other known processes for forming a plastic, such as a thermoplastic rubber having the trade name SANTOPRENE. The leg  74  has a front surface  75  comprising a plurality of grooves  76 , which provide several functions. The grooves  76  “snowplow” the toner on the developer roll and capture toner between the grooves to inhibit leakage. The grooves  76  also direct the toner toward a storage area via rotation of the developer roll D ( FIG. 2 ). The grooves  76  are disposed at an angle, which may be from about zero to about forty-five degrees from the sidewall of the leg  74 . 
     The upper seat portion  72  comprises a seating surface  73 , an upper seat inner seal or seal wall  78  and an upper seat outer seal or seal wall  80 . A gap  86  is disposed between the upper seat inner seal  78  and the upper seat outer seal  80 , wherein the tongue  64  may be closely received within the upper seat portion  72  to interlock the j-seal  70  and the doctor blade seal  60 . The seating surface  73  also comprises an aperture made for receiving an alignment pin for proper positing of the j-seal  70  to the housing  42 . 
     The upper seat inner seal wall  78  extends upwardly from the upper seat surface  73 . The upper seat inner seal  78  is disposed at an acute angle with respect to the outer seal  80  which corresponds to that of the angled surface  68 , so that the upper seat inner seal  78  and angled surface  68  engage one another in sealing fashion. Further, the upper seat inner seal  78  is received within the recess defined by the surfaces  66 ,  68 ,  69 . 
     Referring additionally now to  FIG. 4 , the sealing assembly  38  is depicted from an opposite side as  FIG. 3  and in an exploded perspective view. The upper seat outer seal  80  is depicted extending upwardly above the upper seat surface  73  and from a front edge  75  of the j-seal  70  rearwardly. The upper seat outer seal wall  80  comprises an upper tapered horizontal edge  82  and a curved vertical edge  84 . When the bracket assembly  50  is located on the doctor blade seal  60 , the seal  60  compresses within the j-seal upper seat  72 . Due to this compression, the lower surface of the bracket  52  engages the tapered horizontal edge  82 . Since the upper edge  82  of the upper outer seat seal  80  is tapered, the downward force on the edge  82 , caused by the bracket assembly  50 , results in an inwardly directed component force which pushes the upper seat outer seal  80  inwardly against the doctor blade seal  60 . This causes increased sealing performance along the interface between the j-seal  70  and the end surface  65  of the doctor blade seal  60 . The curved vertical edge  84  matches the profile of the blade  54  to engage the rear surface of the blade  54 . 
     Also extending from the end surface  65  of seal  60  is an edge rib  67 . The rib  67  is deformed so as to be positioned over an edge of the housing wherein the j-seal  70  is seated. Since the rib  67  extends outwardly from the end surface  65 , the upper seat outer seal  80  does not extend rearwardly the entire length of the seating surface  73 . Accordingly, space is provided for the edge rib  67  to extend outwardly beyond the outer seal wall  80 . 
     Referring now to  FIG. 5 , a perspective view of the assembly  38  is depicted with the doctor blade seal  60  positioned in the upper seat portion  72 . The upper seat inner seal  78  is disposed within the recess defined by surfaces  66 ,  68 ,  69 . Further, the angled surface  68  is engaging the upper seat inner seal wall  78 . When the bracket assembly  50  is lowered on the doctor blade seal  60 , the doctor blade seal  60  is compressed so that the seal surfaces  66 ,  68 ,  69  expand to engage inner seal wall  78 . The tongue  64  of the doctor blade seal  60  is extending into and through the j-seal gap  86 . 
     Referring now to  FIG. 6 , the bracket assembly  50  is positioned on the doctor blade seal  60 . The down force of the assembly  50  which is tightened against the housing  42  ( FIG. 2 ) compresses the doctor blade seal  60 . The compressing of the doctor blade seal  60  also forces the doctor blade seal  60  into the corner defined at the junction between the doctor blade  54  and the bracket  52  inhibiting leakage from that path. Additionally, the bracket assembly  50  engages the horizontal edge  82 , providing an inwardly directed force on the upper seat outer seal  80  to improve sealing along the interface between the doctor blade seal  60  and the j-seal  70 . 
     The foregoing description of the various embodiments of the invention has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the claims appended hereto.