Patent Publication Number: US-9417601-B1

Title: Image forming apparatus and structural member

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2015-016855 filed Jan. 30, 2015. 
     BACKGROUND 
     Technical Field 
     The present invention relates to an image forming apparatus and a structural member. 
     SUMMARY 
     According to an aspect of the invention, there is provided an image forming apparatus including a structural member that is attached to and detached from an image forming apparatus body. The structural member includes a portion having a developer transport path for transporting developer to a developing device and a reinforcing member that reinforces the structural member. The reinforcing member has an opening that opens towards the developer transport path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  illustrates an image forming apparatus according to an exemplary embodiment of the present invention; 
         FIG. 2  is a schematic view of a structural member of the image forming apparatus illustrated in  FIG. 1 ; 
         FIG. 3  is a schematic sectional view of the structural member illustrated in  FIG. 2  taken along line III-III in  FIG. 2 ; 
         FIG. 4  illustrates a side surface of the back of the structural member illustrated in  FIG. 2 ; 
         FIG. 5  illustrates a state in which a reinforcing member has been removed from the structural member illustrated in  FIG. 2 ; 
         FIG. 6  illustrates a state in which a portion of a body of the structural member illustrated in  FIG. 2  is cut away; and 
         FIG. 7  illustrates a reinforcing member of the structural member illustrated in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Next, an exemplary embodiment of the present invention is described with reference to the drawings.  FIG. 1  illustrates an image forming apparatus  10  according to the exemplary embodiment of the present invention. As illustrated in  FIG. 1 , the image forming apparatus  10  includes an image forming apparatus body  12 . A discharging opening  14  for discharging sheets, used as recording media, is formed in the image forming apparatus body  12 . An upper surface of the image forming apparatus body  12  is used as a discharging unit  16  onto which a sheet having an image formed thereon is discharged. 
     A process cartridge  300 , used as a structural member, is disposed in the image forming apparatus body  12 . The process cartridge  300  includes a photoconductor drum  310  and a developing device  350 . The photoconductor drum  310  is used as an image holding member that holds an image. The developing device  350  develops a latent image formed on the photoconductor drum  310  with developer. The process cartridge  300  is attachable to and detachable from the image forming apparatus body  12 . Here, the term “process cartridge” refers to one that includes at least a developing device and that is attachable to and detachable from the image forming apparatus body. The process cartridge  300  is described in detail below. 
     In the exemplary embodiment, as the developing device  350 , what is called a two-component developing device is used. The developing device  350  develops a latent image by using a two-component developer containing non-magnetic toner and magnetic carriers. More specifically, the developing device  350  develops a latent image by electrostatically moving toner in a charged state in the developer to the photoconductor drum  310 . In the exemplary embodiment, a device using a two-component developer is hereunder described. The developer may only contain toner, or may contain both toner and carriers. Therefore, it goes without saying that the present invention is not limited to the exemplary embodiment. 
     A latent image forming device  110  is attached to the image forming apparatus body  12 . The latent image forming device  110  forms a latent image on a surface of the photoconductor drum  310  by irradiating the surface of the uniformly charged photoconductor drum  310  with light. As the latent image forming device  110 , for example, a laser irradiation device may be used. 
     A toner replenishing device  120  is disposed in the image forming apparatus body  12 . The toner replenishing device  120  is a device that replenishes the developing device  350  with toner when, for example, toner density of the developer in the developing device  350  becomes low. The toner replenishing device  120  includes a toner container  124  that contains toner and a toner replenishing device body  122  to which the toner container  124  is attached and from which the toner container  124  is detached. The toner replenishing device  120  further includes a toner transport path  126  that connects the interior of the toner container  124  and the developing device  350 , and that is provided for transporting the toner contained in the toner container  124  to the developing device  350 . 
     An air current generating device  140  is attached to the image forming apparatus body  12 . The air current generating device  140  generates air current in the image forming apparatus body  12  by either introducing air into the interior of the image forming apparatus body  12  from the outside of the image forming apparatus body  12  or discharging air in the image forming apparatus body  12  to the outside of the image forming apparatus body  12 . 
     A sheet transport path  500  for transporting sheets is formed in the image forming apparatus body  12 . The sheet transport path  500  includes a main transport path  502  and a reverse transport path  504 . A sheet-feed device  510 , transport rollers  520 , registration rollers  522 , a transfer device  130 , the aforementioned photoconductor drum  310 , a fixing device  150 , and discharge rollers  524  are disposed along the main transport path  502  in that order from an upstream side in a transport direction of a sheet transported in the main transport path  502 . 
     The sheet-feed device  510  includes a sheet container  512  that contains stacked sheets and a sending-out device  514  that sends out a topmost sheet among the stacked sheets towards the main transport path  502 . The transport rollers  520  transport the sheet sent out by the sending-out device  514  towards the registration rollers  522 . 
     The registration rollers  522  temporarily stop movement of a leading end portion of the sheet, and causes the movement of the leading end portion of the sheet towards a nip N, formed by the photoconductor drum  310  and the transfer device  130 , to start again so as to match a timing in which a toner image is formed on the surface of the photoconductor drum  310 . 
     Transfer bias is applied to the transfer device  130 , and the toner image formed on the surface of the photoconductor drum  310  is electrostatically transferred to the sheet. 
     The fixing device  150  fixes the toner image transferred to the sheet by the transfer device  130  by using, at least, heat. 
     The discharge rollers  524  discharge the sheet to which the toner image has been fixed by the fixing device  150  towards the discharging unit  16  so as to cause the sheet to pass through the discharging opening  14 . When a toner image is also to be formed on the other surface of the sheet on whose one surface the toner image has been formed, the discharge rollers  524  start to rotate in a reverse direction at a timing in which a portion near a trailing end portion of the sheet reaches the discharge rollers  524 . By rotating in the reverse direction, the discharge rollers  524  send out the sheet on whose one surface the toner image has been formed to the reverse transport path  504  starting from the trailing end portion of this sheet. 
     For example, three sets of transport rollers, that is, transport rollers  530 , transport rollers  532 , and transport rollers  534  are disposed along the reverse transport path  504  in that order from an upstream side in a sheet transport direction in the reverse transport path  504 . The transport rollers  530 , the transport rollers  532 , and the transport rollers  534  transport the sheet towards the transport rollers  520  while reversing the sheet on whose one surface the toner image has been formed. 
       FIG. 2  schematically illustrates the process cartridge  300 . The process cartridge  300  includes a cartridge body  302 . The aforementioned photoconductor drum  310  is attached to the cartridge body  302  so as to be rotatable in the direction of arrow a shown in  FIG. 2 . The aforementioned developing device  350 , a charging device  312 , and a toner removing device  330  are disposed in the cartridge body  302 . 
     Prior to forming a latent image on the surface of the photoconductor drum  310 , the charging device  312  uniformly charges the surface of the photoconductor drum  310 . 
     The toner removing device  330  is a device that, after a developer image has been transferred to the sheet from the surface of the photoconductor drum  310  by the transfer device  130  (see  FIG. 1 ), removes any toner remaining on the surface of the photoconductor drum  310 . Here, not only the toner, but also carriers in the developer are adhered to the surface of the photoconductor drum  310 . In this case, the toner removing device  330  removes, not only the toner, but also the carriers from the surface of the photoconductor drum  310 . 
     The toner removing device  330  includes a scraping off member  332  and a toner transporting member  334 . One end portion of the scraping off member  332  is secured to the cartridge body  302 , and the other end portion of the scraping off member  332  is pressed against the photoconductor drum  310 . When the photoconductor drum  310  rotates, the other end portion of the scraping off member  332  removes the toner so as to scrape it off from the surface of the photoconductor drum  310 . 
     The toner transporting member  334  is a member that includes, for example, a spiral blade unit and that rotates. For example, when the toner transporting member  334  rotates, the toner that has been scraped off by the scraping off member  332  is transported towards the back (that is, the inner side in the plane of each of  FIGS. 1 and 2 ) of the image forming apparatus  10  and the process cartridge  300 . 
     Through a toner receiving opening  352 , the developing device  350  receives toner supplied from the toner replenishing device  120  (see  FIG. 1 ) and transported in the toner transport path  126 . The developing device  350  includes a developing roller  360 , a developer transporting member  370 , a developer transporting member  380 , and a layer thickness regulating member  390 . 
     The developing roller  360  includes a developing sleeve  362  and a magnet roller  364 . The developing sleeve  362  is used as a developer supplying member that supplies developer to the photoconductor drum  310 . The magnet roller  364  is positioned in the developing sleeve  362  and does not move with respect to the cartridge body  302 . 
     The developing sleeve  362  has a cylindrical shape, is formed of, for example, aluminum, and is rotatable in the direction of arrow b shown in  FIG. 2 . The magnet roller  364  is formed from a permanent magnet with S magnetic poles and N magnetic poles being disposed as appropriate. By magnetic force that is generated from the magnet roller  364 , carriers adhere to a surface of the developing sleeve  362 , and a magnetic brush is held by the surface of the developing sleeve  362 . When charged toner electrostatically moves from the magnetic brush to the photoconductor drum  310 , a latent image formed on the photoconductor drum  310  is developed. 
     The developer transporting member  370  includes a shaft  372  and a spiral blade unit  374 . The shaft  372  is rotatably attached to the cartridge body  302 . The spiral blade unit  374  is attached to the shaft  372 . The developer transporting member  370  rotates to transport the developer already contained in the cartridge body  302  and toner supplied from the toner receiving opening  352  while stirring the developer and the toner. The developer transporting member  380  includes a shaft  382  and a spiral blade unit  384 . The shaft  382  is rotatably attached to the cartridge body  302 . The spiral blade unit  384  is attached to the shaft  382 . The developer transporting member  380  rotates to transport the developer while stirring the developer. 
     The layer thickness regulating member  390  is attached to the cartridge body  302  such that the size of a gap between the layer thickness regulating member  390  and the developing sleeve  362  becomes a predetermined value. When the developing sleeve  362  has rotated in the direction of arrow b, the layer thickness regulating member  390  scrapes off developer held by the developing sleeve  362  while a predetermined thickness of the developer held by the developing sleeve  362  is made to remain on the developing sleeve  362 , to regulate the layer thickness of the developer held by the developing sleeve  362 . 
       FIG. 3  is a schematic sectional view of the process cartridge  300  taken along line III-III in  FIG. 2 . As shown in  FIG. 3 , the process cartridge  300  has a toner transport path  320  for transporting the toner removed from the photoconductor drum  310  by the developer removing device  330  to the developing device  350 . An upper end portion of the toner transport path  320  communicates with the interior of the toner removing device  330 , and a lower end portion of the toner transport path  320  communicates with the interior of the developing device  350 . The toner removed from the surface of the photoconductor drum  310  by the scraping off member  332  and transported towards the back (right in  FIG. 3 ) by the toner transporting member  334  is transported towards the developing device  350  so as to fall in the toner transport path  320 . 
     An accelerating mechanism  340  for suppressing stagnation of the toner in the toner transport path  320  and for accelerating the falling of the toner in the developing device  350  may be provided in the toner transport path  320 . For example, with the accelerating mechanism  340  being connected to the developer transporting member  370 , for example, when the accelerating mechanism  340  moves in, for example, a vertical direction in response to the rotation of the developer transporting member  370 , the falling of the toner that stagnates in the toner transport path  320  in the developing device  350  is accelerated. 
     A reinforcing member  410  that reinforces the process cartridge  300  is attached to a side surface of the process cartridge  300  at a side where the toner transport path  320  is formed. The reinforcing member  410  has an opening  420  that opens towards the toner transport path  320 . At least one opening is formed in the reinforcing member  410 . In the exemplary embodiment two openings, that is, the opening  420  and an opening  430  (see  FIG. 4 ) are formed in the reinforcing member  410 . 
     In the process cartridge  300  having the above-described structure, when, for example, the layer thickness of the developer is regulated by the layer thickness regulating member  390  in the developing device  350 , the developer generates heat due to friction. When an image is to be formed on the other surface of a sheet on whose one surface an image has been formed, the sheet that has been heated when fixing a toner image to the one surface of the sheet by the fixing device  150  contacts the photoconductor drum  310 , as a result of which the photoconductor drum  310  is heated. 
     Toner that has been heated along with the photoconductor drum  310  is removed by the toner removing device  330  from the surface of the heated photoconductor drum  310 , and the heated toner is transported into the developing device  350  via the toner transport path  320 . For these reasons, the developer in the developing device  350  becomes very hot. Therefore, the quality of an image that is formed may be reduced due to, for example, fusing of the developer that has become very hot. Consequently, it is desirable to accelerate heat dissipation from the developer and cool the developer. 
     The process cartridge  300  is attached to and detached from the image forming apparatus body  12 . Therefore, for example, an operator may accidentally cause the process cartridge  300  to fall when, for example, attaching the process cartridge  300  to or detaching the process cartridge  300  from the image forming apparatus body  12 . It is desirable for, for example, the process cartridge to have strength so as not to be broken when, for example, the process cartridge is caused to fall from the image forming apparatus body  12 . A structure in which the cartridge body  302  is provided with, for example, an urging unit (not shown), such as a spring, and in which the developing roller  360  is pressed against the photoconductor drum  310  by the urging unit may be used. In this case, it is desirable that the process cartridge  300  have strength so as not to be broken by urging by the aforementioned urging unit. 
       FIG. 4  illustrates a side surface of the back of the process cartridge  300 . As shown in  FIG. 4 , the aforementioned opening  420  and the aforementioned opening  430  are formed in the reinforcing member  410 . Air current generated by the aforementioned air current generating device  140  (see  FIG. 1 ) passes through the opening  420  and the opening  430 . The reinforcing member  410  includes a connecting portion  412 , a connecting portion  414 , and a connecting portion  416 . The connecting portion  412 , the connecting portion  414 , and the connecting portion  416  of the reinforcing member  410  are described in detail below. 
     As shown in  FIG. 4 , the opening  420  has a width c. 
       FIG. 5  illustrates the side surface of the back of the process cartridge  300  in a state in which the reinforcing member  410  has been removed. As shown in  FIG. 5 , the toner transport path  320  has a width d, which is equal to the width c. That is, the opening  420  (see  FIG. 4 ) has the same width as the toner transport path  320  along the toner transport path  320 . 
       FIG. 6  illustrates the process cartridge  300  in a state in which a portion of the cartridge body  302  has been cut away. As mentioned above, the upper end of the toner transport path  320  communicates with the interior of the toner removing device  330 , and the lower end of the toner transport path  320  communicates with the interior of the developing device  350 . 
       FIG. 7  illustrates the reinforcing member  410 . As shown in  FIG. 7 , in the reinforcing member  410 , a protrusion  418  that reinforces the reinforcing member  410  is formed over of the entire periphery of the opening  420 . The protrusion  418  is formed at a portion of the periphery of the opening  430 . In the exemplary embodiment, although the protrusion  418  is formed around the entire periphery of the opening  420 , the protrusion  418  may be formed around part of the opening  420 . In addition, in the exemplary embodiment, although the protrusion  418  is formed around part of the opening  430 , the protrusion  418  may be formed around the entire portion of the periphery of the opening  430 . 
     Although, in the exemplary embodiment, the protrusion  418  is formed on a surface of the reinforcing member  410  at a side of the toner transport path  320  so as to protrude at the side of the toner transport path  320 , the protrusion  418  may be formed on a surface of the reinforcing member  410  at a side that is opposite to the toner transport path  320  so as to protrude at the side opposite to the toner transport path  320 . 
     As shown in  FIG. 7 , the aforementioned connecting portion  412  connects a first side portion  424  of the reinforcing member  410 , which forms a first side  422  of the opening  420 , and a second side portion  438  of the reinforcing member  410 , which forms a second side  426  of the opening  420  that opposes the first side  422 , to each other. The connecting portion  412  is inclined with respect to the first side  422  and the second side  426 . Similarly to the connecting portion  412 , the aforementioned connecting portion  414  also connects the first side portion  424  of the reinforcing member  410 , which forms the first side  422  of the opening  420 , and the second side portion  438  of the reinforcing member  410 , which forms the second side  426  of the opening  420  that opposes the first side  422 , to each other. The connecting portion  414  is inclined with respect to the first side  422  and the second side  426  similarly to the connecting portion  412 . 
     The aforementioned connecting portion  416  connects a first side portion  434  of the reinforcing member  410 , which forms a first side  432  of the opening  430 , and a second side portion  438  of the reinforcing member  410 , which forms a second side  436  of the opening  430  that opposes the first side  432 , to each other. The connecting portion  416  is inclined with respect to the first side  432  and the second side  436 . 
     As described above, the present invention is applicable to an image forming apparatus, such as a copying machine, a facsimile apparatus, or a printer, and to a structural member that is used in, for example, such an image forming apparatus. 
     The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.