Abstract:
An image forming apparatus includes an image carrying member; an image forming section to form a toner image on the image carrying member; a transferring section to transfer the toner image formed on the image carrying member to a sheet; a fixing section to fix the toner image onto the sheet; a sheet feeding section to feed a sheet to the transferring section; a sheet tray to store sheets to be fed by the sheet feeding section; a dehumidifying heater arranged to the sheet tray and to perform dehumidification for sheets; a waste toner box arranged to adjoin the sheet tray and to accommodate waste toner; and a partition member arranged between the sheet tray and the waste toner box and between the dehumidifying heater and the waste toner box.

Description:
[0001]    This application is based on Japanese Patent Application No. 2007-218179 filed on Aug. 24, 2007 in Japanese Patent Office, the entire content of which is hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an image forming apparatus, such as a copying machine, a printer, and a facsimile, in particular to a waste toner box and a sheet tray in detail. 
         [0003]    Conventionally, in the image forming apparatus which has a series of electronic photograph processes, toner remaining on an image carrying member is removed by a cleaning member, such as a cleaning blade, and is accommodated in a waste toner box provided under the cleaning member. Moreover, in order to reduce a dead space in an apparatus and to make a maintenance work easy, it has been well known to structure the apparatus such that a waste toner box is arranged to adjoin beside a sheet tray accommodating section, and the sheet tray and the waste toner box are attached or detached from the same direction. 
         [0004]    In the above-mentioned structures, at the time of attaching or detaching the above-mentioned waste toner box, when a discharging port of a conveying passage to convey waste toner from the cleaning member to the waste toner box is separated from a joint port of the waste toner box, there has been problems that waste toner scatters from the discharging port and the joint port and pollutes the circumference. 
         [0005]    For the above-mentioned problem, there has been disclosed an apparatus in which a waste toner box is arranged at a side of a sheet tray accommodating section provided under the main body of the apparatus so as to accommodate the sheet tray and a joint section between a waste toner conveying means and a relay duct is displaced from the top of the sheet tray (for example, refer to Patent document 1). 
         [0006]    Further, there has been disclosed a waste toner recovery apparatus in which a waste toner box is arranged at a side of a sheet tray accommodating section to accommodate a sheet tray to store sheets and there is provided a forcibly conveying means for forcibly conveying waste toner to the waste toner box. At the time of separating a discharging section from the waste toner box, the forcibly conveying means is rotated reversely so as to draw waste toner into a conveying section and to prevent waste toner from scattering to the circumference. 
         [0007]    Patent document 1: Japanese Patent Unexamined Publication No. 5-61385 
         [0008]    Patent document 2: Japanese Patent Unexamined Publication No. 5-297773 
         [0009]    Patent document 1 prevents waste toner from falling while utilizing an empty space in a sheet tray accommodating section effectively. However, it is difficult to prevent waste toner from scattering to the circumference and it is not sufficient to prevent dirt of sheets. 
         [0010]    In Patent document 2, it is unable to draw waste toner adhering to a discharging port into the conveying section, and it is not sufficient to prevent scattering of waste toner. 
         [0011]    As mentioned above, it is unable to say that it is enough to prevent scattering of waste toner, and also it is unable to say that it is enough to prevent dirt of sheets. 
         [0012]    Moreover, a dehumidifying heater is provided to a sheet tray in order to dehumidify sheets. In this structure, heat generated by the dehumidifying heater is transferred to a waste toner box and the heat hardens waste toner in the vicinity of the waste toner box. As a result, the hardened waste toner interferes the fluidity of waste toner at the time of waste toner recovery and makes it difficult to recover waste toner. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention was conceived in view of the above-mentioned situation, and an object of the invention is to provide an image forming apparatus capable of preventing dirt of sheets caused by the scattering of toner and not lowering the fluidity of waste toner with heat of a dehumidifying heater at the time of waste toner recovery. 
         [0014]    The above object can be attained the following structures. 
         [0015]    An image forming apparatus, comprises: 
         [0016]    an image carrying member; 
         [0017]    an image forming section to form a toner image on the image carrying member; 
         [0018]    a transferring section to transfer the toner image formed on the image carrying member to a sheet; 
         [0019]    a fixing section to fix the toner image onto the sheet; 
         [0020]    a sheet feeding section to feed a sheet to the transferring section; 
         [0021]    a sheet tray to store sheets to be fed by the sheet feeding section; 
         [0022]    a dehumidifying heater arranged to the sheet tray and to perform dehumidification for sheets; 
         [0023]    a waste toner box arranged to adjoin the sheet tray and to accommodate waste toner; and 
         [0024]    a partition member arranged between the sheet tray and the waste toner box and between the dehumidifying heater and the waste toner box. 
         [0025]    With the above structures, it becomes possible to prevent waste toner scattered from the waste toner box from entering into the sheet tray, whereby the dirt of sheets can be prevented. Moreover, it can be prevented that heat of the dehumidifying heater transfer to the waste toner box, whereby the hardening of waste toner in the vicinity of the waste toner box due to the heat can be prevented. As a result, the fluidity of waste toner to be recovered to the waste toner box can be maintained, and waste toner can be recovered to the waste toner box smoothly without the adhesion of the waste toner onto the conveying passage. 
         [0026]    With the above structures, when the above partition member is structured so as to constitute a part of reinforcing members to reinforce a body of the apparatus, the strength for the space to arrange the sheet tray and the waste toner box can be maintained without adding another reinforcing member, thereby saving costs. 
         [0027]    With the above structures, that is, when the waste toner box is arranged at the upstream side of the sheet tray in the sheet feeding direction and the partition member is arranged between the waste toner box and the sheet tray and between the dehumidifying heater and the waste toner box, a space for a maintenance work can be secured in the sheet feeding passage, thereby conducting maintenance easily. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0028]      FIG. 1  is a cross-sectional schematic view showing an example of an image forming apparatus according to the present invention. 
           [0029]      FIG. 2  is a schematic view showing a conveyance passage of waste toner. 
           [0030]      FIG. 3  is a partial view showing a part near a partition member. 
       
    
    
     EXPLANATION OF SIGNS  
       [0031]      
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 A 
                 Image forming apparatus 
               
               
                   
                 SC 
                 Image reading apparatus 
               
               
                   
                 P 
                 Sheet 
               
               
                   
                 5Y, 5M, 5C, 5K, 8 
                 Cleaning section 
               
               
                   
                 6 
                 Intermediate transfer member 
               
               
                   
                 9 
                 Transferring section 
               
               
                   
                 20 
                 Sheet feeding section 
               
               
                   
                 21 
                 Sheet tray 
               
               
                   
                 30 
                 Fixing device 
               
               
                   
                 50 
                 waste toner box 
               
               
                   
                 60 
                 Partition member 
               
               
                   
                 P1, P2, P3, P5, P6, P7 
                 Toner recovery pipe 
               
               
                   
                 64 
                 Dehumidifying heater 
               
               
                   
                   
               
             
          
         
       
     
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0032]    An embodiment of an image forming apparatus according to the present invention will be described with reference to drawings. However, the present invention is not limited to the following embodiment. 
         [0033]      FIG. 1  is a cross-sectional schematic view showing an example of an image forming apparatus according to the present invention. 
         [0034]    The image forming apparatus according to the present invention comprises an apparatus main part A and an image reading apparatus (hereinafter, referred to as scanner) SC. The apparatus main part A is called a tandem type color image forming apparatus and comprises plural sets of image forming sections  10 Y,  10 M,  10 C, and  10 K, a belt-like intermediate transfer member  6 , a transferring section  9  being a transferring means, a sheet feeding section  20 , and a fixing device  30 . The sheet feeding section  20  is also used as a sheet tray accommodating section. 
         [0035]    A scanner SC is installed in the upper part of the apparatus main part A. An image on a document placed on a document sheet stand S 1  of the scanner SC is scanned with exposure by an optical system and is read into a line image sensor CCD. 
         [0036]    Image signals are formed through a photoelectric conversion by the line image sensor CCD, subjected to an analog processing, an A/D conversion, a shading compensation, and an image compression processing In an image processing section, and thereafter sent to exposing sections  3 Y,  3 M,  3 C and  3 K. 
         [0037]    In an image forming section  10 Y to form a yellow (Y) color toner image, a charging section  2 Y, the exposing section  3 Y, a developing device  4 Y, and a cleaning section  5 Y are arranged around a photoreceptor drum  1 Y. In an image forming section  10 M to form a magenta (M) color toner image, a charging section  2 M, the exposing section  3 M, a developing device  4 M, and a cleaning section  5 M are arranged around a photoreceptor drum  1 M. In an image forming section  10 C to form a cyan (C) color toner image, a charging section  2 C, the exposing section  3 C, a developing device  4 C, and a cleaning section SC are arranged around a photoreceptor drum  1 C. In an image forming section  10 K to form a black (K) color toner image, a charging section  2 K, the exposing section  3 K, a developing device  4 K, and a cleaning section  5 K are arranged around a photoreceptor drum  1 K. 
         [0038]    Here, the developing devices  4 Y,  4 M,  4 C, and  4 K store two component type developer composed of carrier and small particle size toner of yellow (Y), Magenta (M), cyan (C), and black (K). The toner in this embodiment contains a wax component such as fatty ester, for example, in an amount of 8 to 12 parts by weight and is manufactured by a polymerizing method. However, the toner is not limited to this toner. 
         [0039]    The intermediate transfer member  6  is wound around plural rollers, and is supported so as to be rotatable. Respective color component toner images formed by the image forming sections  10 Y,  10 M,  10 C, and  10 K are transferred respectively as the first time transfer by the transferring sections  7 Y,  7 M,  7 C, and  7 K onto the rotating intermediate transfer member  6 . Thereby, the respective color component toner images are superimposed on the intermediate transfer member  6  so as to form a color image on the intermediate transfer member  6 . 
         [0040]    A sheet P stored in the sheet tray  21  of the sheet feeding section  20  is fed out by a feed roller  22 , and conveyed to the transferring section  9  through feed rollers  23 ,  24 ,  25  and  26  and a registration roller  27 , whereby the color toner image is transferred as the second time transfer onto the sheet P. The sheet trays  21  are supported such that each sheet tray can be pulled out from the front side of the apparatus in  FIG. 1 . Sheets P can be placed in each of the sheet trays  21  at the position where each of the sheet trays  21  is pulled out from the apparatus. 
         [0041]    The fixing device  30  comprises a fixing roller  31  which has an elastic member layer on a metallic core and a built-in heater and a pressing roller  32  which is arranged at a position opposite to the fixing roller and is able to come in pressure contact with the fixing so as to form a fixing nip section. When a sheet P bearing a toner image passes through the fixing nip section in such a way that the toner image surface comes in contact with the fixing roller, the toner image is heated, pressed and fixed onto the sheet P. 
         [0042]    After that, the sheet P in which the color toner image was fixed on the sheet P is held between paper ejecting rollers  28  and is delivered and placed on a delivery tray  29  at the outside of the apparatus. 
         [0043]    On the other hand, after the color toner image has been transferred from the intermediate transfer member  6  to the sheet by the transferring section  9 , residual toner on the intermediate transfer member  6  is removed by the cleaning section  8 . 
         [0044]    Here, the above embodiment of the image forming apparatus was the image forming apparatus to form a color image. However, it may be also an image forming apparatus to form a monochrome image. 
         [0045]    Waste toner removed by the cleaning sections  5 Y,  5 M,  5 C,  5 K, and  8  is stored in a waste toner box  50  via a conveyance passage of waste toner. 
         [0046]      FIG. 2  is a schematic view showing a conveyance passage of waste toner. In  FIG. 2 , the intermediate transfer member  6 , the transferring section  9 , and the fixing device  30  are omitted for explanation. 
         [0047]    Pipes P 1  through P 7  to convey waste toner and to recover waste toner are arranged near an outer wall of the apparatus main part A. In this embodiment, those pipes are arranged along the outer wall at the rear side in  FIG. 2  (in the direction toward to the reverse side of the sheet of  FIG. 2 ). The pipe P 1  connects the cleaning section SY and the pipe P 5 . Similarly, pipes P 2  to P 4  connect the cleaning sections  5 M,  5 C, and  5 K and P 5 , respectively. The pipe P 5  is connected to the pipe P 6 , and the pipe P 6  is connected to the pipe P 7 , and further the pipe P 7  is connected detachably to the waste toner box. 
         [0048]    The waste toner recovered by the cleaning section SY is conveyed in the direction toward to the rear side in the cleaning section  5 Y in  FIG. 2  and then conveyed to the pipe P 1 . The waste toner conveyed to the pipe P 1  is conveyed to the pipe P 5  by a conveying mechanism (un-illustrated in drawings) provided in the pipe P 1 . As the conveying mechanism, a conveying mechanism to provide a spiral screw in a pipe P 1  for example and to send waste toner into the pipe P 5  by rotating the screw with a drive motor may be employed. Similarly, the waste toner recovered by the cleaning sections SM,  5 C, and  5 K is also conveyed to the pipe P 5 . 
         [0049]    The waste toner recovered by the cleaning section  8  is conveyed in the direction toward to the rear side (in the direction toward to the reverse side of the sheet of  FIG. 2 ) in the cleaning section  8  and then conveyed to the pipe P 5 . 
         [0050]    The waste toner conveyed to the pipe P 5  drops through the inside of the pipe P 5 , and is conveyed to the pipe P 6 . It is desirable to provide an adhesion prevention mechanism (un-illustrating) to the pipe P 5  so that waste toner may not adhere or solidify in the pipe P 5  so as not to become obstacle to the dropping of waste toner. As examples of the adhesion prevention mechanism, an adhesion prevention mechanism to provide a rudder-like member in the pipe P 5  and to move the rudder-like member up and down in the inside of the pipe P 5  with a drive mechanism so as to prevent adhesion may be employed. Moreover, an oscillation may be provided to the pipe  5 . 
         [0051]    The waste toner conveyed to the pipe P 6  is conveyed to the pipe P 7  by a conveying mechanism provided in the pipe P 6 . As the conveying mechanism, a conveying mechanism similar to the conveying mechanism in the pipe  5  may be employed. 
         [0052]    The waste toner conveyed to the pipe P 7  drops through the inside of a pipe P 7 , and is accommodated in the waste toner box  50 . It is desirable to provide the pipe P 7  with a adhesion prevention mechanism similar to the above-mentioned adhesion prevention device provided to the pipe  5 . Thereby, the adhesion of waste toner in the pipe P 7  can be prevented. 
         [0053]    The waste toner box  50  is arranged so as to adjoin the sheet tray  21  at the upstream side in the sheet feeding direction. The waste toner box  50  is installed in such a way that the waste toner box  50  can be detached from the front side of the apparatus in  FIG. 1 , that is, in the direction to detach the sheet trays  21 . With this arrangement, it becomes possible to attach or detach the sheet trays  21  and the waste toner box  50  in the same direction, whereby their operability can be improved. Moreover, since the waste toner box  50  is arranged so as to adjoin the sheet tray  21  at the upstream side in the sheet feeding direction, the space for a maintenance can be secured on a sheet feeding passage at the downstream side in the sheet feeding direction in the sheet trays  21 , thereby its maintenance ability for jam of sheets can be improved. 
         [0054]    The partition member  60  is arranged between the waste toner box  50  and the sheet trays  21 . In  FIG. 3 , A 11  and A 12  represent a part of a frame of the apparatus main part.  FIG. 3  is a segmentary view near the partition member  60 . The partition member  60  is guided by a guide member provided in the apparatus, and is positioned in a specified position of the apparatus. In this embodiment, the partition member  60  is guided by a guide member A 13  provided in a frame A 11 , and a guide member A 14  provided in a frame A 12 . 
         [0055]    After the partition member  60  is positioned in the specified position, bent sections  61 ,  62 , and  63  of the partition member  60  are fixed to a frame of the apparatus main body with screw. Thereby, the partition member  60  can be constituted as a part of reinforcement members to reinforce the apparatus main body. The guide members, the positions fixed with screws, and so on are not limited to this embodiment, and are suitably determined in accordance with the structure of the apparatus main body, the configuration of the partition member  60 , and so on. In the example of  FIG. 3 , as for the rear side of the partition member  60  (in the direction toward to the reverse side of the sheet of  FIG. 3 ) is fixed by a bent section  63  and the front side (in the direction toward to the front side of the sheet of  FIG. 3 ) is fixed in bent sections  61  and  62 . 
         [0056]    With this arrangement, even when waste toner scatters at the side of the waste toner box  50 , the partition member  60  shelters such that waste toner does not enter into the sheet tray  21 . Moreover, the partition member  60  shelters such that heat of the dehumidifying heater  64  arranged in a sheet tray does not transfer to the side of the waste toner box  50 . 
         [0057]    A metal, resin, etc. may be used for the partition member  60 . However, since the partition member  60  is fixed with screws so as to be constituted as a reinforcement member of the apparatus main body, a metal is used preferably. 
         [0058]    By the above, even when waste toner scatters at the side of the waste toner box  50 , it can be sheltered such hat waste toner may not enter into the sheet tray  21  side, and the dirt of sheet P can be prevented. Moreover, it can be sheltered such that heat of the dehumidifying heater  64  may not be transferred to the side of the waste toner box, and adhesion of waste toner in the vicinity of the jointing port between the pipe P 7  and the waste toner box  50  or in the waste toner box  50  can be prevented.