Patent Publication Number: US-10307929-B2

Title: Punching apparatus

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a punching apparatus configured to punch a sheet. 
     Description of the Related Art 
     A sheet processing apparatus including a processing mechanism, which is configured to perform post-processing on a sheet, is mounted to a main apparatus, e.g., a conventional image forming apparatus configured to form an image on the sheet. 
     As the processing mechanism, there are known a binding mechanism configured to perform binding processing on sheets after gathering and stacking the sheets, a punching mechanism configured to punch file holes in a sheet to store the sheet therein, a folding mechanism configured to perform folding processing on a sheet to store the sheet therein, and a printing mechanism configured to print a predetermined stamp on a sheet to store the sheet therein. 
     The punching mechanism, which has a punching function of performing punching processing on a sheet, includes a punch member and a die member, which are configured to punch a sheet on which an image is formed in a main body of the image forming apparatus. The punch member and the die member are arranged opposite to each other so as to interpose a sheet on a sheet conveyance path therebetween. A blade at a tip of the punch member is inserted into a hole of the die member, thereby punching the sheet. The above-mentioned punching mechanism includes a chad box configured to store chads formed by performing punching processing on the sheet (Japanese Patent Application Laid-Open No. 2010-58944). The chad box is arranged below the die member, and receives the falling chads. 
     The sheet is charged with static electricity during conveyance of the sheet and during image formation on the sheet, and the chads stored in the chad box are also charged with electricity. The chads charged with electricity may be attracted onto an inner wall surface of the chad box, or fly about against other chads charged with electricity. Consequently, this poses a problem in that the chads scatter in the chad box. Further, a problem in that the chads fly out of the chad box arises. 
     SUMMARY OF THE INVENTION 
     The present invention provides a punching apparatus including a chad box configured to store a chad of a sheet. 
     According to one embodiment of the present invention, there is provided a punching apparatus, comprising:
         a punching portion configured to punch a sheet; and   a chad box configured to store a chad of a sheet punched by the punching portion,   wherein the chad box comprises:   a first inner wall portion formed of an insulator; and   a second inner wall portion formed of a conductor and arranged above the first inner wall portion.       

     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view for illustrating a configuration of an image forming system including a punching apparatus. 
         FIG. 2  is an enlarged sectional view for illustrating a configuration of the punching processing portion serving as the punching apparatus. 
         FIG. 3  is a perspective view for illustrating a chad box of the punching apparatus. 
         FIG. 4  is a top view for illustrating the chad box of the punching apparatus. 
         FIG. 5  is a sectional view for illustrating the chad box of the punching apparatus. 
         FIG. 6A ,  FIG. 6B , and  FIG. 6C  are schematic views for illustrating operation of the punching mechanism of the punching apparatus. 
         FIG. 7A ,  FIG. 7B , and  FIG. 7C  are schematic views for illustrating a state in which chads are stored in the chad box. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Preferred embodiments of the present invention will now be described in detail in accordance with the accompanying drawings. 
       FIG. 1  is a sectional view for illustrating a configuration of an image forming system  100  including a punching apparatus  30 . The image forming system  100  includes an image forming apparatus A, a post-processing apparatus B including the punching apparatus  30 , and an image reading apparatus C. The image reading apparatus C is arranged above the image forming apparatus A. 
     The post-processing apparatus B includes the punching apparatus  30  configured to punch a sheet, and a binding apparatus  40  configured to bind sheets. In the following description, the punching apparatus  30 , which is configured to punch a sheet, is referred to as a punching processing portion  30 , and the binding apparatus  40 , which is configured to bind sheets, is referred to as a binding processing portion  40 . As described above, the post-processing apparatus B includes the punching processing portion  30  configured to punch a sheet, the binding processing portion  40  configured to bind sheets, and a first stack tray  20  onto which punched and/or bound sheets are delivered. The post-processing apparatus B includes a sheet delivery path  22  and a second stack tray  21 . A sheet conveyed from the image forming apparatus A through the sheet delivery path  22  is delivered onto the second stack tray  21  without being post-processed. 
     The image forming apparatus A illustrated in FIG. will be described. The image forming apparatus A includes a main housing  1  as a main body. In the main housing  1 , there are arranged a sheet feeding portion  2 , an image forming portion  4 , and a conveying portion  7 . The sheet feeding portion  2  stores sheets on which images are to be formed. 
     The sheet feeding portion  2 , the image forming portion  4 , and the conveying portion  7  are arranged in a frame (not shown) of the main housing  1 . The sheet feeding portion  2  includes a plurality of sheet feeding cassettes capable of storing sheets different in size, and a sheet feeding path  3  through which a sheet is conveyed from each of the sheet feeding cassettes to the image forming portion  4 . The image forming portion  4  forms an electrostatic latent image on photosensitive members (a drum and an endless belt) with a light beam emitted from a light source such as a semiconductor laser or a light emitting diode (LED), and then develops the image with toner (ink). After that, the image is transferred onto a sheet by a charger. Then, the image is fixed on the sheet by a heating device  6  (fixing rollers), and the sheet is conveyed to a first delivery port  11   a  or a second delivery port  11   b  of the main housing  1  through a sheet delivery path  9 . 
     The conveying portion  7  includes the sheet delivery path  9  through which a sheet is conveyed from the image forming portion  4  to the first delivery port  11   a  or the second delivery port  11   b , a plurality of conveying rollers, and a conveying belt. The first delivery port  11   a  and the second delivery port  11   b  are formed at different positions in the main housing  1 . Accordingly, the sheet delivery path  9  includes a first branch path  9   a  and a second branch path  9   b  which branch off therefrom. Through the first branch path  9   a , the sheet is conveyed to the first delivery port  11   a . Meanwhile, through the second branch path  9   b , the sheet is conveyed to the second delivery port  11   b.    
     Further, a sheet to be post-processed is conveyed through the first branch path  9   a  to the first delivery port  11   a . A sheet that is not to be post-processed is conveyed through the second branch path  9   b  to the second delivery port  11   b . Further, the conveying portion  7  includes a duplex path  8  through which a sheet having an image formed thereon is reversed and then conveyed to the image forming portion  4  again. 
     The image reading apparatus C includes a platen (not shown) on which an original is to be set, a carriage (not shown) including a light source (not shown) configured to irradiate the original, and a reading element (not shown) configured to receive reflected light from the original through scanning (moving) of the carriage. The reading element photoelectrically converts the reflected light, to thereby read an image on the original. Further, a feeder unit, which is configured to feed originals, is mountable to the platen. Originals set on a feed tray are separated one by one, and are conveyed to a reading portion of the platen. After images are read, the originals are delivered onto a delivery tray. 
     As illustrated in  FIG. 1 , the post-processing apparatus B includes the punching processing portion  30 , the binding processing portion  40 , the first stack tray  20 , the second stack tray  21 , an upstream sheet path  23  formed in the punching processing portion  30 , a downstream sheet path  24  formed in the binding processing portion  40 , and the sheet delivery path  22  formed above the upstream sheet path  23 . 
     A punching unit  31 , which is configured to punch a sheet, is arranged in the punching processing portion  30 . The punching unit  31  punches a sheet guided along the upstream sheet path  23 , and then conveys the sheet to the binding processing portion  40 . 
     A binding unit  41  is arranged in the binding processing portion  40 . The binding unit  41  includes a processing tray  42  on which sheets are gathered and stacked, and a binding mechanism  43  mounted to the processing tray  42 . The processing tray  42  includes a support surface configured to support a trailing edge of a sheet conveyed through the downstream sheet path  24 . The binding mechanism  43  is arranged on one end side of the processing tray  42 , and is configured to bind the sheets stacked on the processing tray  42 . A conveying belt  44  is arranged on the processing tray  42 . The conveying belt  44  conveys the bundle of sheets along the support surface of the processing tray  42 . Further, the bundle of sheets bound is conveyed by the conveying belt  44 , and is delivered onto and stacked on the first stack tray  20 . Further, the second stack tray  21 , onto which a sheet conveyed from the image forming apparatus A is delivered without being post-processed, is arranged above the binding processing portion  40 . 
     Now, the punching processing portion  30  will be described in detail.  FIG. 2  is an enlarged sectional view for illustrating a configuration of the punching processing portion  30  serving as the punching apparatus. The punching processing portion  30  includes the punching unit  31 , the upstream sheet path  23  and the sheet delivery path  22  through which a sheet is guided, a conveying roller pair  32  configured to convey the sheet along the upstream sheet path  23 , and a delivery roller pair configured to deliver the sheet guided through the sheet delivery path  22 . 
     The punching unit  31  includes a punching mechanism (a punching portion)  33  configured to punch a sheet passing through the upstream sheet path  23 , and a chad box  50  configured to store chads of a sheet punched by the punching mechanism  33 . 
     The punching mechanism  33  includes a punch member  34  including a punch blade  34   a  configured to punch a sheet, and a die member  35  having a receiving hole  35   a  formed therein. The punch member  34  and the die member  35  are arranged opposite to each other across the upstream sheet path  23 . 
     The punch member  34  is mounted in a freely swingable manner to a cam holder  38  through a support shaft  39 . The cam holder  38  is mounted in a freely rotatable manner to a rotary cam (eccentric cam)  36 . A rotation shaft  37  is driven to rotate through drive of a drive source (not shown), thereby rotating the rotary cam  36 . Further, the rotation shaft  37  is rotated by 180 degrees so that the punch member  34  makes a vertical reciprocating motion. In this manner, punching processing is performed. 
       FIG. 6A ,  FIG. 6B , and  FIG. 6C  are schematic views for illustrating operation of the punching mechanism  33 . As illustrated in  FIG. 6A , in a state in which a sheet K is stopped at a predetermined punching position in the upstream sheet path  23 , the rotation shaft  37  is driven to rotate, thereby rotating the rotary cam  36  by 90 degrees from an initial position ( FIG. 6A ). Thus, as illustrated in  FIG. 6B , the punch member  34  pierces through the sheet K, and is lowered to a position of the die member  35  below the upstream sheet path  23 , thereby punching the sheet. Subsequently, the rotary cam  36  is further rotated by 90 degrees (rotated by 180 degrees from the initial position). In this manner, as illustrated in  FIG. 6C , the punch member  34  is retreated to a position above the upstream sheet path  23 . Further, the punched sheet is conveyed by the conveying roller pair  32  into the downstream sheet path  24 . Chads S of the sheet punched by the punching mechanism  33  fall into the chad box  50  arranged below the die member  35 . 
       FIG. 3  is a perspective view for illustrating the chad box  50 .  FIG. 4  is a top view for illustrating the chad box  50 .  FIG. 5  is a sectional view for illustrating the chad box  50 . The chad box  50  is arranged below the die member  34  of the punching mechanism  33 , and is mounted to the post-processing apparatus B in a freely removable manner. As illustrated in  FIG. 3 , the chad box  50  is formed into an elongated rectangular parallelepiped shape and made of a resin. The chads S of a sheet punched by the punching mechanism  33  fall into the chad box  50  so as to be stored in the chad box  50 . Further, a grip  51  is arranged at one end of the chad box  50  in a longitudinal direction of the chad box  50 . The grip  51  is gripped by a user when the user pulls out the chad box  50  from the post-processing apparatus B. 
     A conductive member is arranged at a predetermined position inside the chad box  50  in a height direction of inner wall surfaces of the chad box  50  in which the chads S are collected. The inner wall surfaces of the chad box  50  are formed of an insulator made of a resin, and a conductor formed of the conductive member. That is, a bottom-surface-side inner wall portion of the inner wall surfaces of the chad box  50  is formed of the insulator, and an inner wall portion above the bottom-surface-side inner wall portion is formed of the conductor. Thus, a portion of the inner wall surfaces from a bottom surface to a predetermined height of the chad box  50  is divided into two layers. In the embodiment, as illustrated in  FIG. 3  and  FIG. 4 , a metal wire  55  is used as the conductive member. Further, in addition to the above-mentioned grounded conductive wire  55 , a fullness detector  60  is mounted to the chad box  50 . The fullness detector  60  is configured to detect whether or not the chad box  50  is full of the chads S. 
     The fullness detector  60  is an optical sensor including a light emitting element and a light receiving element. In the vicinity of an opening in an upper portion of the chad box  50 , the fullness detector  60  is arranged on one of opposed inner wall surfaces of the chad box  50  extending along a longitudinal direction thereof. Further, a reflecting plate  61  is arranged on another inner wall surface opposed to the one of the inner wall surfaces on which the fullness detector  60  is arranged. That is, the fullness detector  60  is configured such that the reflecting plate  61  reflects light emitted from the light emitting element, and that the light receiving element receives the reflected light. 
     Next, as illustrated in  FIG. 3 ,  FIG. 4 , and  FIG. 5 , the conductive wire  55  is extended on a lower side of the fullness detector  60  over a substantially center portion in the height direction (vertical direction) of the chad box  50  along a horizontal direction of the inner wall surfaces. Specifically, a plurality of mounting portions  52  are formed on the four inner wall surfaces of the chad box  50  along the horizontal direction of the inner wall surfaces. Conductive support screws  53   a  to  53   e  serving as support members, which are configured to support the wire  55 , are mounted to the mounting portions  52 , respectively. Further, one wire  55  is sequentially wound around bodies of the plurality of support screws  53   a  to  53   e , thereby extending the wire  55  along the horizontal direction of the inner wall surfaces of the chad box  50 . In the embodiment, one end of the wire  55  is wound around the first support screw  53   a , and the wire  55  is sequentially wound along the inner wall surfaces of the chad box  50  around the second support screw  53   b , the third support screw  53   c , and the fourth support screw  53   d  in the stated order. Finally, another one end of the wire  55  is wound around the fifth support screw  53   e.    
     A regulating member  54  is formed on each portion between the screws on the inner wall surface of the chad box  50 , and is configured to regulate the wire  55  toward the inner wall surface. In the embodiment, the regulating member  54  comprises a hook of an unciform shape and regulates the wire  55  by the wire  55  being interposed between the regulating member  54  and the inner wall surface of the chad box  50 . 
     Further, a ground spring  56  serving as a ground member is mounted on an outer side surface of the chad box  50  on another end side different from the side on which the grip  51  is mounted. The ground spring  56  includes an elastic portion coiled into a spiral shape, and a linear portion extended into a linear shape. An end of the linear portion of the ground spring  56  is wound around the body of the third support screw  53   c . With this configuration, at the body of the third support screw  53   c , conduction is established between the wire  55  and the ground spring  56 . Meanwhile, when the chad box  50  is mounted to the post-processing apparatus B, an end of the elastic portion of the ground spring  56  is brought into contact with a metal frame (not shown) of the post-processing apparatus B, to thereby be grounded through the metal frame. That is, the wire  55  is grounded through the ground spring  56  and the metal frame of the post-processing apparatus B so as to remove static electricity charging the chads S in the chad box  50 . 
       FIG. 7A ,  FIG. 7B , and  FIG. 7C  are schematic views for illustrating a state in which the chads S are stored in the chad box  50 . The chads S of a sheet punched by the punching mechanism  33  fall into the chad box  50  by their own weights, and are stored in a heap shape in the chad box (see  FIG. 7A ). At this time, a part of the chads S charged with electricity are attracted onto the inner wall surfaces of the chad box  50 . The wire  55  formed of the conductor has a larger attracting force because an electric potential of the chads S with respect to the wire  55  formed of the grounded conductor is higher than an electric potential of the chads S with respect to the insulator made of a resin. Accordingly, the chads S attracted onto the inner wall surfaces of the chad box  50  are attracted toward the wire  55  (see  FIG. 7B ). Thus, as a height of the chads S stored in the chad box  50  becomes closer to a height of the wire  55 , a height of a heap of the chads S is gradually leveled (see  FIG. 7C ). The height of the heap of the chads S is leveled in the above-mentioned manner, and hence the chads S do not reach a fullness detection position P 1  in a state in which there is still a large space in the chad box  50 , and the fullness detector  60  can detect fullness when a proper amount of the chads S is stored. 
     In addition, the wire  55  is extended over a position below the fullness detector  60 . Accordingly, at least the chads S having fallen down to a position below the wire  55  are attracted to the wire  55 , thereby reducing a sticking of the chads S on the fullness detector  60 . Thus, frequency of false detection of the fullness detector caused by the sticking of the chads S can also be reduced. 
     That is, in the above-mentioned embodiment, the bottom-surface-side inner wall portion of the chad box  50  is formed of the insulator (resin), and an inner wall portion on the opening side with respect to the inner wall portion formed of the insulator is formed of the conductor (wire). The inner wall surfaces of the chad box  50  are formed into the above-mentioned two-layer structure including the insulator and the conductor, thereby being capable of substantially leveling the height of the heap of the chads S. Further, the two-layer structure including the insulator and the conductor is formed on the bottom side with respect to the fullness detector  60 , thereby being capable of preventing the chads S from sticking on the fullness detector  60 . 
     In the above-mentioned embodiment, the wire  55  is extended over four inner wall side surfaces of the chad box  50 , but the wire  55  may be mounted only on opposed longitudinal surfaces (surfaces extending in the longitudinal direction of the chad box  50 ) among the inner wall side surfaces of the chad box  50  along the horizontal direction of the inner wall side surfaces. In this case, wires  55  respectively mounted on the opposed longitudinal surfaces among the inner wall surfaces of the chad box  50  may be separately connected and electrically conducted to the ground spring  56  mounted on the outer side surface of the chad box  50 , and may be grounded in this manner. 
     Further, in the above-mentioned embodiment, the conductive wire  55  is used as an extended member. However, as long as a grounded conductive member is used, a member other than the wire  55  may be used. For example, even when, as the extended member, a band-like metal plate is mounted on the lower side of the fullness detector  60  along the horizontal direction of the inner wall surfaces, the same effects as those of the above-mentioned embodiment can be obtained. 
     Still further, in the above-mentioned embodiment, the ground spring  56  is used to ground the conductive wire  55  through the frame of the post-processing apparatus B. However, the wire  55  may be connected to a self-discharge mechanism so as to discharge an electric charge. 
     According to the above-mentioned embodiment, scatter of the chads S in the chad box  50  can be suppressed. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2016-030763, filed Feb. 22, 2016, which is hereby incorporated by reference herein in its entirety.