Patent Publication Number: US-10328595-B2

Title: Post-processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2017-032139 filed Feb. 23, 2017. 
     BACKGROUND 
     (i) Technical Field 
     The present invention relates to a post-processing apparatus. 
     (ii) Related Art 
     In a post-processing apparatus that performs post-processing, such as stapling or punching, on a recording medium, such as a printing sheet, on which a printing operation has been performed, plural printing sheets on each of which post-processing is to be performed are stored in a storing unit called a compilation tray, and then the post-processing is performed on the stored printing sheets. 
     When ejecting a stack of printing sheets produced by performing post-processing, such as stapling, on plural printing sheets stored in the compilation tray, in order to eject the printing sheets stored in the compilation tray even in the case where the number of the printing sheets stored in the compilation tray is large, it is necessary to increase the height of a hook that latches onto trailing ends of the printing sheets. Thus, in the case where the number of the printing sheets to be ejected is small, for example, one, the probability of the trailing end of the printing sheet becoming caught in the hook increases. 
     SUMMARY 
     According to an aspect of the invention, there is provided a post-processing apparatus including a storing unit in which plural recording media are stored for performing post-processing, and a pushing member that latches onto and pushes trailing ends of the recording media stored in the storing unit toward an ejection port. When the number of the recording media stacked on the storing unit is small, the pushing member latches onto and pushes the trailing ends of the recording media at a position different from a position at which the pushing member latches onto and pushes the trailing ends of the recording media when the number of the recording media stacked on the storing unit is large. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a perspective view illustrating the appearance of a post-processing apparatus according to an exemplary embodiment of the present invention; 
         FIG. 2  is a diagram illustrating a state in which the post-processing apparatus according to the exemplary embodiment of the present invention is used by being connected to a printer; 
         FIG. 3  is a schematic sectional view illustrating the configuration of a principal mechanism for performing post-processing in the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 4  is a perspective view illustrating the peripheral portion of stoppers in the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 5  is a diagram illustrating the state of the stoppers mounted on one of ejection belts in the configuration illustrated in  FIG. 4 ; 
         FIG. 6  is an enlarged view of one of the stoppers having the structure illustrated in  FIG. 5 ; 
         FIG. 7A  and  FIG. 7B  are respectively a diagram illustrating a stopper body and a diagram illustrating a connecting member; 
         FIG. 8  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 9  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 10  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 11  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 12  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 13  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 14  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 15  is a diagram illustrating the operation of the post-processing apparatus according to the exemplary embodiment of the present invention; 
         FIG. 16  is a diagram illustrating the operation of a post-processing apparatus according to a comparative example; 
         FIG. 17  is a diagram illustrating the operation of the post-processing apparatus according to the comparative example; 
         FIG. 18  is a diagram illustrating a modification of the stoppers; and 
         FIG. 19  is a diagram illustrating another modification of the stoppers. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present invention will now be described in detail below with reference to the drawings. 
       FIG. 1  is a perspective view illustrating the appearance of a post-processing apparatus  10  according to an exemplary embodiment of the present invention. 
     As illustrated in  FIG. 1 , the post-processing apparatus  10  according to the exemplary embodiment of the present invention has a shape such that the post-processing apparatus  10  is used by being connected to a printer. The post-processing apparatus  10  has a function of performing post-processing, such as stapling, on plural printing sheets ejected from the printer and then ejecting a stack of the printing sheets, on which the post-processing has been performed to an ejection tray  30 . 
     A state in which the post-processing apparatus  10  is used by being connected to a printer  90  is illustrated in  FIG. 2 . 
       FIG. 2  illustrates a state in which the post-processing apparatus  10  ejects, to the ejection tray  30 , a stack of printing sheets obtained by performing post-processing, such as stapling, on printing sheets that are ejected from the printer  90  and introduced into the post-processing apparatus  10 . 
     The configuration of the post-processing apparatus  10  according to the present exemplary embodiment for performing post-processing on printing sheets and performing an ejecting operation that is to be performed after the post-processing will now be described. 
       FIG. 3  is a schematic sectional view illustrating the configuration of a principal mechanism for performing post-processing in the post-processing apparatus  10  according to the present exemplary embodiment. Note that  FIG. 3  is a schematic sectional view illustrating an operation for ejecting a stack of printing sheets performed by the post-processing apparatus  10  and does not accurately illustrate the positional relationship in the actual configuration. 
     Referring to  FIG. 3 , the post-processing apparatus  10  according to the present exemplary embodiment includes transport rollers  21 , sub-paddles  22 , main paddles  23 , an end guide  24 , a compilation tray  25 , an ejection port  26 , ejection belts  27 , stoppers  28 , rotating rollers  29 , and the ejection tray  30 . 
     The transport rollers  21  transport printing sheets that are ejected from a printer or the like and on which post-processing is to be performed. 
     The compilation tray  25  is a storing unit in which plural printing sheets are stored for performing post-processing. Post-processing such as, for example, stapling or punching is performed on a stack of printing sheets stored in the compilation tray  25  by a post-processing mechanism (not illustrated). 
     The main paddles  23  and the sub-paddles  22  are each formed in such a manner as to have the shape of a paddle (blade) having flexibility and are transport members that transport the printing sheets in a given direction as a result of rotating. 
     The sub-paddles  22  transport one of the printing sheets transported from the upstream side of a transport path by the transport rollers  21  in a direction toward the compilation tray  25 . More specifically, the sub-paddles  22  transport a recording medium, such as a printing sheet, to the compilation tray  25  as a result of rotating while being in contact with a surface of the recording medium. 
     Each of the sub-paddles  22  according to the present exemplary embodiment includes blades each of which comes into contact with one of the printing sheets and reinforcing portions each of which reinforces the strength of a portion of a corresponding one of the blades that does not come into contact with the printing sheet. 
     The main paddles  23  keep transporting one of the printing sheets transported by the sub-paddles  22  further toward the compilation tray  25  until an end of the printing sheet reaches the end guide  24 . 
     The end guide  24  is a sheet-aligning unit used for aligning a trailing end of a stack of the printing sheets accommodated in the compilation tray  25 . 
     A tamper (not illustrated) operates in accordance with the timing at which the printing sheets reach the end guide  24  such that alignment of a stack of the printing sheets on the compilation tray  25  in a width direction is performed. 
     Each of the ejection belts  27  is an endless belt member and is stretched between a corresponding two of the rotating rollers  29 . 
     Each of the stoppers  28  is a hook member that latches onto a trailing end of a stack of printing sheets. A pair of the stoppers  28  are mounted on each of the ejection belts  27 . 
     The ejection belts  27  are driven when ejecting a stack of printing sheets on which the post-processing has been performed. As a result of each of the ejection belts  27  being driven, the corresponding two stoppers  28  perform an operation for ejecting the stack of printing sheets, on which the post-processing has been performed in the compilation tray  25 , from the ejection port  26  by moving while rotating by 180 degrees for each movement so as to hook and push the trailing end of the stack of printing sheets. The ejection belts  27  and the stoppers  28  function as pushing members that hook and push the trailing ends of the printing sheets stored in the compilation tray  25  toward the ejection port  26 . 
     The peripheral structure of the stoppers  28  in the post-processing apparatus  10  according to the present exemplary embodiment is illustrated in  FIG. 4 . 
       FIG. 4  illustrates the two ejection belts  27  on each of which the corresponding two stoppers  28  are mounted. 
     Referring to  FIG. 4 , one of the two rotating rollers  29 , each of which is located on one end side of a corresponding one of the two ejection belts  27 , is provided with a motor (not illustrated) serving as a driving source that drives the corresponding ejection belt  27  so that the corresponding ejection belt  27  rotates. When the motors are driven, the rotating rollers  29  are caused to rotate in such a manner that the two ejection belts  27  rotate at the same time and that the stoppers  28  move in parallel with each other. 
       FIG. 5  illustrates a state in which two of the stoppers  28  in the configuration illustrated in  FIG. 4  are mounted on one of the ejection belts  27 , and  FIG. 6  is an enlarged view of one of the stoppers  28  having the structure illustrated in  FIG. 5 . 
     A hook  32  and a step portion  36  are formed on a surface of each of the stoppers  28 , the surface facing a direction of movement of the stopper  28 . 
     Each of the hooks  32  is formed at an end portion of the corresponding stopper  28  in such a manner as to project in the direction of movement of the stopper  28 . The hook  32  functions as a first hook portion that latches onto the trailing end of a stack of a large number of printing sheets stacked on the compilation tray  25 . 
     Each of the step portions  36  is formed in a sawtooth shape or a substantially sawtooth shape at a position closer to the corresponding ejection belt  27  than the corresponding hook  32  is when the stopper  28  is mounted on the ejection belt  27 . The step portion  36  functions as a second hook portion that latches onto the trailing end of a stack of a small number of printing sheets stacked on the compilation tray  25 . As a result of being formed in a sawtooth shape or a substantially sawtooth shape, the step portion  36  may easily latch onto the trailing end of a stack of printing sheets. 
     In other words, the hooks  32  or the step portions  36  are latched onto the trailing end of a stack of printing sheets in accordance with the number of the printing sheets on the compilation tray  25  and push the stack of printing sheets toward the ejection port  26 . 
       FIG. 7A  and  FIG. 7B  are diagrams each illustrating an exploded state of one of the stoppers  28  having the structure illustrated in  FIG. 6  that has been removed from the corresponding ejection belt  27 . The stopper  28  includes a stopper body  37  and a connecting member  38  connected to the stopper body  37 .  FIG. 7A  is a diagram illustrating a connecting surface of the stopper body  37  that is connected to the connecting member  38 .  FIG. 7B  is a diagram illustrating a connecting surface of the connecting member  38  that is connected to the stopper body  37 . 
     As illustrated in  FIG. 7A , the stopper body  37  includes a body portion  37   a  that includes the step portion  36 , two to-be-connected portions  37   b  each of which is cut out in a quadrangular shape, a projecting portion  37   c  that includes the hook  32  and projects from the body portion  37   a , and a recess  37   d  that is formed in the body portion  37   a  by being recessed. One of the ejection belts  27  is mounted in the recess  37   d . When the ejection belt  27  is mounted in the recess  37   d , the outer peripheral surface of the recess  37   d  is formed so as to be straight. A center portion of the inner peripheral surface of the recess  37   d  is recessed in such a manner as to follow the shape of the ejection belt  27 , and the inner peripheral surface is inclined from the center portion toward the end portions thereof to a larger extent than the shape of the ejection belt  27 . The end portions of the recess  37   d  are formed by being recessed in such a manner as to be wider than the center portion of the recess  37   d.    
     As illustrated in  FIG. 7B , the connecting member  38  includes a body portion  38   a , two connecting portions  38   b  that are to be connected to the two to-be-connected portions  37   b  of the stopper body  37 , and a recess  38   c  formed in the body portion  38   a  by being recessed. One of the ejection belts  27  is mounted in the recess  38   c . When the ejection belt  27  is mounted in the recess  38   c , the outer peripheral surface of the recess  38   c  is formed so as to be straight. A center portion of the inner peripheral surface of the recess  38   c  is recessed in such a manner as to follow the shape of the ejection belt  27 , and the inner peripheral surface is inclined from the center portion toward the end portions thereof to a larger extent than the shape of the ejection belts  27 . The end portions of the recess  38   c  are formed by being recessed in such a manner as to be wider than the center portion of the recess  38   c.    
     The end portions of the ejection belt  27  are fitted into the recess  37   d  of the stopper body  37  and the recess  38   c  of the connecting member  38  so as to be sandwiched between the stopper body  37  and the connecting member  38 , and the connecting portions  38   b  of the connecting member  38  are mounted on and connected to the to-be-connected portions  37   b  of the stopper body  37 . 
     When the stopper body  37  is mounted on the ejection belt  27 , and the connecting member  38  is connected to the stopper body  37 , for example, spaces K are formed between the ejection belt  27 , the stopper body  37 , and the connecting member  38  in a curved portion of the ejection belt  27  as illustrated in  FIG. 6 . Each of the spaces K functions as a curve-absorbing portion that absorbs the curve of the ejection belt  27 . More specifically, a base portion of the stopper  28  on the rear side of the stopper  28  when the stopper  28  is brought into contact with the ejection belt  27  has a structure in which the spaces K absorb the curve of the ejection belt  27  such that the stopper  28  is connected to the ejection belt  27 . 
     In other words, the stopper body  37  has a structure in which a load generated as a result of the stopper  28  being pulled by the ejection belt  27  when the stopper  28  passes across the curved portion of the ejection belt  27  is reduced by being connected to the connecting member  38  while the spaces K are formed therebetween, so that the stopper  28  smoothly passes across the curved portion of the ejection belt  27 . 
     Each of the stoppers  28  according to the present exemplary embodiment is detachable from the corresponding ejection belt  27 , and when the stopper  28  is required to be replaced due to deterioration thereof, the stopper  28  may be easily replaced. In addition, each of the stoppers  28  is capable of being mounted on a versatile belt member. 
     Each of the ejection belts  27  is formed of, for example, an elastic member made of an elastic rubber or the like, which is a material such as ethylene-propylene-diene rubber (EPDM) having a high elastic limit and a low modulus of elasticity. The stopper bodies  37  and the connecting members  38  are each formed of, for example, a member made of a resin. 
     The operation of the post-processing apparatus  10  according to the present exemplary embodiment will now be described with reference to  FIG. 8  to  FIG. 15 . 
     First, in an initial state, the blades of the sub-paddles  22  are stationary at positions where the blades face away from a sheet transport path as illustrated in  FIG. 8 . 
     Thus, as illustrated in  FIG. 9 , a printing sheet P transported by the transport rollers  21  passes under the sub-paddles  22  without being hindered and then stops. 
     In the state illustrated in  FIG. 9 , when power is supplied to the motors so as to cause the sub-paddles  22  to start rotating, as illustrated in  FIG. 10 , the blades of the sub-paddles  22  are brought into contact with the printing sheet P, and the printing sheet P is transported in the direction toward the compilation tray  25 . 
     Then, as illustrated in  FIG. 11 , the printing sheet P is brought into contact with the main paddles  23  and transported by the main paddles  23  until the printing sheet P abuts against the end guide  24 . 
     Subsequently, when the next printing sheet P is transported by the transport rollers  21 , an operation similar to the above is performed, and as a result, the plural printing sheets P are accommodated and stacked one on top of the other in the compilation tray  25  as illustrated in  FIG. 12 . 
     When a predetermined number of printing sheets P are accommodated in the compilation tray  25  by repeating such control, post-processing is performed on a stack of the printing sheets P. 
     When the stack of the printing sheets P, on which the post-processing has been performed, is ejected from the ejection port  26 , as illustrated in  FIG. 13 , the motors are brought into a non-operating state, and each of the sub-paddles  22  is caused, by a spring, to stop at a stop position at which the sub-paddle  22  does not hinder the passage of the printing sheets P. In this state, when each of the ejection belts  27  is driven by a driving source (not illustrated), as illustrated in  FIG. 13  and  FIG. 14 , the step portions  36  of the stoppers  28  latch onto and push the trailing end of the stack of the printing sheets P such that the stack of the printing sheets P is ejected from the ejection port  26 . As a result, as illustrated in  FIG. 15 , the stack of the printing sheets P, which has been ejected, falls onto the ejection tray  30 . 
     By performing control such as that described above, a stack of printing sheets obtained by performing the post-processing on plural printing sheets, on each of which a printing operation has been performed, is ejected to the ejection tray  30 . 
       FIG. 16  and  FIG. 17  illustrate an example in which a stopper  1  that employs a belt-ejection system and that does not include the step portion  36  is used. The stopper  1  includes a hook  2  that latches onto the trailing end of a stack of printing sheets. 
     Modifications of the stoppers  28 , which have been described above, will now be described with reference to  FIG. 18  and  FIG. 19 . 
     As illustrated in  FIG. 18 , a stopper  48  according to one of the modifications includes the hook  32 , which is included in each of the above-described stoppers  28 , and a step portion  34  having a step-like shape or a substantially step-like shape. Also in the stopper  48  according to the present modification, in the case where the number of printing sheets stacked on the compilation tray  25  is large, a surface that is located on the inner surface side of the hook  32  and is located between the hook  32  and the step portion  34  latches onto an end portion of a stack of the printing sheets, and in the case where the number of the printing sheets is small, a lower surface of the step portion  34  latches onto the end portion of the stack of the printing sheets in such a manner that the stopper  48  pushes the stack of the printing sheets toward the ejection port  26 . 
     As illustrated in  FIG. 19 , a stopper  58  according to the other modification includes the step portion  36 , which is included in each of the above-described stoppers  28  and which has a sawtooth shape or a substantially sawtooth shape, and the step portion  36  is formed in such a manner as to be inclined. 
     Modifications 
     In the above-described exemplary embodiment, although a case has been described in which the present invention is applied to a post-processing apparatus that is configured to be installed onto a printer, the present invention is not limited to such a post-processing apparatus and may also be applied to post-processing apparatuses each having any structure for performing post-processing on a sheet on which a printing operation has been performed. 
     In addition, in the above-described exemplary embodiment, although a configuration has been described in which a stopper is detachable from an ejection belt, the present invention is not limited to this configuration, and a stopper and an ejection belt may be integrally formed into one member. 
     Furthermore, in the above-described exemplary embodiment, although a configuration has been described in which two stoppers are mounted on one ejection belt, the present invention is not limited to this configuration, and an ejection belt may be provided with at least one stopper. 
     The foregoing description of the exemplary embodiments 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 embodiments were 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.