Patent Grant
9764920
Field of the Invention
The present invention relates to a sheet processing apparatus and an image forming apparatus, and, in particular, to an apparatus configured to bind sheets together without the use of a staple or other external device.
Description of the Related Art
Conventionally, some image forming apparatuses, such as copying machines, laser beam printers, facsimile apparatuses, and multifunction peripherals as combinations thereof, have been provided with a sheet processing apparatus configured to perform binding processing on sheets. Generally, such image forming apparatuses bind a sheet bundle with the use of a metallic staple. Such stapling processing allows a plurality of output sheets to be securely bound at a position specified by a user, and therefore is employed in a large number of sheet processing apparatuses.
However, although the stapling processing using a metallic staple allows the sheet bundle to be bound securely, a special tool should be used to release the sheet bundle once it is bound by this processing. Further, this processing requires work to remove the staple before the stapled sheets are put through a shredder. Similarly, when the stapled sheet bundle is recycled, the staple should also be removed, and the sheets and the staple should be separately collected.
Therefore, apparatuses configured to bind sheets without the use of a staple, especially in consideration of recyclability, are proposed among conventional sheet processing apparatuses. These sheet processing apparatuses, for example, include apparatuses configured to perform binding processing on a sheet bundle by a binding unit including V-shaped upper teeth and inverted V-shaped lower teeth (see Japanese Patent Application Laid-Open Nos. 2010-189101 and 2011-201653).
According to these sheet processing apparatuses, after sheets are bundled together and aligned to one another, the lower teeth and the upper teeth of the binding unit are engaged with each other to form an uneven surface on a part of the sheet bundle in a thickness direction to cause respective fibers of the stacked sheets in the sheet bundle to be entangled with one another, thereby binding the sheet bundle. In other words, these sheet processing apparatuses are configured to bind fibrous sheets without the use of a staple. Hereinafter, a term “staple-free binding” will be used to refer to this method of binding a fibrous sheet bundle without the use of a staple.
However, according to these conventional sheet processing apparatuses, an increase in an applied force to fasten the sheets more securely results in the sheet bundle getting stuck to the teeth. The sheet bundle sticking to the teeth produces problems, such as, impeding conveyance of the sheet bundle to be presented to a user for collection or to a next step in the printing process.
The present invention is directed to a sheet processing apparatus capable of preventing sheets from becoming stuck to teeth when the sheets are bound.
According to an aspect of the present invention, a sheet processing apparatus includes a binding unit including a first portion and a second portion, and configured to nip a sheet bundle between the first portion and the second portion to deform the sheet bundle in a thickness direction so as to bind the sheet bundle, and a detachment unit configured to urge the bound sheet bundle toward the second portion to detach the bound sheet bundle from the first portion.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. Each of the exemplary embodiments of the present invention described below can be implemented solely or as a combination of a plurality of the exemplary embodiments or features thereof where necessary or where the combination of elements or features from individual exemplary embodiments in a single exemplary embodiment is beneficial.
In the following description, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
Referring to
The image forming unit 900B includes photosensitive drums a to d configured to form toner images of four colors, i.e., yellow, magenta, cyan, and black, and an exposure device 906 configured to emit a laser beam based on image information to form an electrostatic latent image on each of the photosensitive drums a to d. Each of these photosensitive drums a to d is driven by a motor (not illustrated). Further, a primary charging device, a developing device, and a transfer charging device (not illustrated) are disposed around each of the photosensitive drums a to d. Each of the photosensitive drums a to d and these devices are unitized as process cartridges 901a to 901d.
Further, the image forming unit 900B includes an intermediate transfer belt 902 configured to be rotationally driven in a direction indicated by an arrow, a secondary transfer unit 903 configured to transfer a full color image sequentially formed on the intermediate transfer belt 902 onto a sheet P, and the like. Then, transfer biases are applied to this intermediate transfer belt 902 by transfer charging devices 902a to 902d, which causes the toner images of the respective colors on the photosensitive drums a to d to be sequentially transferred onto the intermediate transfer belt 902 in a multilayered manner. As a result, the full color image is formed on the intermediate transfer belt 902.
The secondary transfer unit 903 includes a secondary transfer counter roller 903b supporting the intermediate transfer belt 902, and a secondary transfer roller 903a in contact with the secondary transfer counter roller 903b via the intermediate transfer belt 902. Referring to
Next, an image forming operation of the image forming apparatus 900 configured in this manner will be described. Upon a start of the image forming operation, first, the exposure device 906 emits laser light based on image information from a personal computer (not illustrated) or the like, and sequentially exposes the surfaces of the photosensitive drums a to d, which have been evenly charged so as to have predetermined polarities and potentials, thereby forming electrostatic latent images on the photosensitive drums a to d. After that, these electrostatic latent images are developed by toners to be visualized.
For example, first, the exposure device 906 emits laser light based on an image signal corresponding to a yellow component color on a document onto the photosensitive drum a via a polygonal mirror of the exposure device 906 and the like, thereby forming a yellow electrostatic latent image on the photosensitive drum a. Then, this yellow electrostatic latent image is developed by a yellow toner from the developing device, and is visualized as a yellow toner image. After that, this toner image arrives at a primary transfer portion where the photosensitive drum a is in contact with the intermediate transfer belt 902, according to a rotation of the photosensitive drum a. At this time, upon the arrival of the toner image at the first transfer unit in this manner, the yellow toner image on the photosensitive drum a is transferred onto the intermediate transfer belt 902 by a primary transfer bias applied by the transfer charging device 902a (a primary transfer).
Subsequently, upon a movement of a portion of the intermediate transfer belt 902 that bears the yellow toner image, a magenta toner image formed on the photosensitive drum b by this time in a similar manner to the above-described method, is transferred onto the intermediate transfer belt 902 from above the yellow toner image. Similarly, as the intermediate transfer belt 902 moves, a cyan toner image, and a black toner image are respectively transferred onto the intermediate transfer belt 902 at respective primary transfer portions while being superimposed onto the yellow toner image and the magenta toner image. As a result, the full color toner image is formed on the intermediate transfer belt 902.
Further, in parallel with this toner image forming operation, the sheet P contained in the sheet feeding cassette 904 is transmitted by the pickup roller 908 one by one. Then, from conveyance guide 125, the sheet P reaches the registration rollers 909, and is conveyed to the secondary transfer unit 903 after being synchronized by the registration rollers 909. After that, the toner images of the four colors on the intermediate transfer belt 902 are collectively transferred onto the sheet P at this secondary transfer unit 903 by a secondary transfer bias applied to the secondary transfer roller 903a, which is a transfer unit (a secondary transfer).
Subsequently, the sheet P with the toner images transferred thereon is guided from the secondary transfer unit 903 to a conveyance guide 920, and is conveyed to a fixing unit 905. The sheet P receives heat and a pressure while being transmitted through the fixing unit 905, by which the toner images are fixed onto the sheet P. After that, the sheet P with the images fixed thereon in this manner is transmitted through a discharge passage 921 disposed downstream of the fixing unit 905, and is then discharged by a pair of discharge rollers 918 to be conveyed to the finisher 100.
The finisher 100 takes in sheets discharged from the apparatus main body 900A sequentially. The finisher 100 includes a processing unit 139 configured to perform processing of aligning a plurality of received sheets to one another and bundling them into a single bundle, and binding processing of binding the bundled sheet bundle at an upstream edge thereof in a sheet discharge direction (hereinafter referred to as a trailing edge). Further, as illustrated in
Further, front and lateral alignment plates 109a and 109b are disposed on the intermediate processing tray 107. The front and lateral alignment plates 109a and 109b regulate (align) the positions of both side edges of the sheet P in a width direction (a lateral direction) after the sheet P is conveyed onto the intermediate processing tray 107 from a direction perpendicular to a lateral direction of the apparatus main body 900A. The front and lateral alignment plates 109a and 109b, which are a side edge alignment unit configured to align the positions of the side edges of the sheet P loaded on this intermediate processing tray 107 in the width direction, are driven to be moved in the width direction by an alignment motor M253 illustrated in
Further, normally, these front and lateral alignment plates 109a and 109b are moved to reception positions where they receive the sheet P by the alignment motor M253 driven based on a detection signal of an alignment home position (HP) sensor (not illustrated). Then, when the front and lateral alignment plates 109a and 109b regulate the positions of the both side edges of the sheet P loaded on the intermediate processing tray 107, the alignment motor M253 is driven to move the front and lateral alignment plates 109a and 109b along the width direction into contact with the both side edges of the sheet P loaded on the intermediate processing tray 107.
Further, a pull-in paddle 106 is disposed above a downstream side of the intermediate processing tray 107 in the conveyance direction. Before the sheet P is conveyed into the processing unit 139, a paddle elevating motor M252 is driven based on detection information of a paddle HP sensor S243 illustrated in
Further, when the sheet P is discharged onto the intermediate processing tray 107, the pull-in paddle 106 is moved downward by driving of the paddle elevating motor M252 in a reverse direction, and is also rotated in a counterclockwise direction by a not-illustrated paddle motor at an appropriate timing. This rotation allows the pull-in paddle 106 to pull in the sheet P and bring the trailing edge of the sheet P into contact with a trailing edge stopper 108. In the present exemplary embodiment, this pull-in paddle 106, the trailing edge stopper 108, and the front and lateral alignment plates 109a and 109b constitute an alignment unit 130, which aligns the sheet P loaded on the intermediate processing tray 107. For example, if the intermediate processing tray 107 is largely inclined, the sheet P can be brought into contact with the trailing edge stopper 108 without the use of the pull-in paddle 106, and a knurled belt 117 that will be described below.
Referring to
Further, the finisher 100 includes a pair of inlet rollers 101 for taking the sheet P into the apparatus, and a sheet discharge roller 103. The sheet P discharged from the apparatus main body 900A is transferred to the pair of inlet rollers 101. At this time, the sheet transfer timing is also simultaneously detected by an inlet sensor S240. Then, the sheet P transferred to the pair of inlet rollers 101 is sequentially discharged onto the intermediate processing tray 107 by the sheet discharge roller 103 (i.e., a sheet discharge unit). The sheet P discharged onto the intermediate processing tray 107 is brought into contact with the trailing edge stopper 108 by a return unit such as the pull-in paddle 106 and the knurled belt 117. As a result, the sheets are aligned to one another in the sheet conveyance direction, thereby forming an aligned sheet bundle.
Referring to
Further, a static charge eliminator 104 and a bundle holder 115 are provided. The bundle holder 115 is rotated by a bundle holder motor M255 illustrated in
The binding processing unit 100A includes a staple-free binding unit 102, which is a staple-free binding unit. As illustrated in
The gear 1025 is attached to a rotational shaft 1026. Then, as illustrated in
Referring to
In the present exemplary embodiment, the cam 1027 is in contact with a roller 1028 disposed at one swingable end of the upper arm 1029 from below. As a result, a rotation of the cam 1027 causes the cam-side end of the upper arm 1029, which has been in pressure contact with the cam 1027 via the roller 1028 by a biasing member (not illustrated) until then as illustrated in
On the other hand, the upper teeth 10210, which are a first tooth form, are provided at a bottom of an end of the upper arm 1029 on the opposite side of the cam 1027. The lower teeth 10214, which are a second tooth form, are provided at a top of an end of the lower arm 1012 on the opposite side of the cam 1027. Referring to
When the cam-side end of the upper arm 1029 is moved upward by the cam 1027, the end of the upper arm 1029 opposite to the cam 1027 is moved downward. According to the downward movement of the end of the upper arm 1029 opposite to the cam 1027, the upper teeth 10210 are moved downward to be engaged with the lower teeth 10214, thereby pressing the sheet bundle. Then, when the sheet bundle is pressed in this manner, the sheet P is stretched, so that a fiber on the surface thereof is exposed. Further pressing of the sheet bundle causes the fibers of the sheets to be entangled with one another, thereby fastening the sheets to one another. The upper teeth 10210 and the lower teeth 10214 are a pair of sandwiching members (nipping members) configured to sandwich the sheet bundle to deform it in the thickness direction to thereby bind it.
In other words, when the staple-free binding unit 102 performs the binding processing on the sheets, the upper arm 1029 is swung to cause the upper teeth 10210 on the upper arm 1029 and the lower teeth 10214 on the lower arm 1012 to bite and press the sheets therebetween. The sheets are bitten and pressed by the upper teeth 10210 and the lower teeth 10214, thereby being fastened to one another. At this time, the position of the cam 1027 is detected by a cam sensor S247 illustrated in
Further, referring to
Then, this image signal control unit 206 outputs this data to a printer control unit 207, and the printer control unit 207 outputs the data received from the image signal control unit 206 to a exposure control unit (not illustrated). An image on a document read by an image sensor (not illustrated) mounted on the image reading apparatus 950 is output from an image reader control unit 205 to the image signal control unit 206, and the image signal control unit 206 outputs this image output to the printer control unit 207.
Further, an operation unit 210 includes a plurality of keys for setting various kinds of functions regarding image formation, a display unit for displaying a setting state, and the like. Then, the operation unit 210 outputs a key signal corresponding to a user's operation performed on each key to the CPU circuit unit 200, and also displays corresponding information on the display unit based on a signal from the CPU circuit unit 200.
The CPU circuit unit 200 controls the image signal control unit 206 and also controls the document conveyance device 950A (refer to
In the present exemplary embodiment, the finisher control unit 220 is mounted on the finisher 100, and drives and controls the finisher 100 by exchanging information with the CPU circuit unit 200. Alternatively, the finisher control unit 220 may be mounted on the apparatus main body side integrally with the CPU circuit unit 200, and may be configured to directly control the finisher 100 from the apparatus main body side.
Further, the finisher control unit 220 drives a conveyance motor M250, the tray elevating motor M251, the paddle elevating motor M252, the alignment motor M253, the assist motor M254, the bundle holder motor M255, and the staple-free binding motor M257 via a driver 225.
Further, the inlet sensor S240, a sheet discharge sensor S246, the tray HP sensor S241, the tray lower limit sensor S242, the paddle HP sensor S243, the assist HP sensor S244, and the bundle holder HP sensor S245 are connected to the finisher control unit 220. Further, the cam sensor S247 is connected to the finisher control unit 220. Then, the finisher control unit 220 drives the alignment motor M253, the staple-free binding motor M257, and the like based on detection signals from these respective sensors.
At the time of execution of the staple-free binding on the sheets, first, the finisher control unit 220, which controls an operation of the staple-free binding unit 102, detects the position of the cam 1027 by the cam sensor S247. Then, at the time of reception of the sheets before exertion of the staple-free binding, the finisher control unit 220 controls a rotation of the staple-free binding motor M257 so that the cam 1027 is positioned at a bottom dead center as illustrated in
At the time of the exertion of the binding operation, the finisher control unit 220 rotates the staple-free binding motor M257 to swing the upper arm 1029 by the cam 1027 about the axis 10211 in the clockwise direction. Then, when the cam 1027 reaches a top dead center as illustrated in
If the cam 1027 is further rotated after the cam 1027 has reached the top dead center, the roller 1028 can get over the top dead center of the cam 1027 by a deflection of a deflection portion 1029a formed on the upper arm 1029. Then, once the roller 1028 has gotten over the top dead center of the cam 1027 in this manner, the upper arm 1029 is moved in a direction for separating the upper teeth 10210 from the lower teeth 10214. After that, when the cam 1027 is further rotated to reach the bottom dead center again, the cam sensor S247 detects the cam 1027. With this operation, the finisher control unit 220 stops the rotation of the staple-free binding motor M257.
Next, a sheet binding processing operation of the finisher 100 according to the present exemplary embodiment will be described. As illustrated in above-described
Subsequently, the sheet P transferred to the pair of inlet rollers 101 is transferred from the pair of inlet rollers 101 to the sheet discharge roller 103. The leading edge of the sheet P is discharged onto the intermediate processing tray 107 while static electricity is removed therefrom by the static charge eliminator 104, at the same time as being conveyed while lifting up the trailing edge drop member 105. The sheet P discharged onto the intermediate processing tray 107 by the sheet discharge roller 103 is pushed from above due to the weight of the trailing edge drop member 105, which can reduce a time taken for the trailing edge of the sheet P to drop onto the intermediate processing tray 107.
Subsequently, the finisher control unit 220 controls the inside of the intermediate processing tray 107 based on a signal of the trailing edge of the sheet P, which is detected by the sheet discharge sensor S246. More specifically, as illustrated in above-described
After conveying the sheet P conveyed thereto by the pull-in paddle 106 to the trailing edge stopper 108, the knurled belt 117 conveys the sheet P while slipping thereon, thereby constantly biasing the sheet P toward the trailing edge stopper 108. This slipping conveyance can bring the sheet P into contact with the trailing edge stopper 108, thereby correcting a skew of the sheet P. Subsequently, after bringing the sheet P into contact with the trailing edge stopper 108 in this manner, the finisher control unit 220 drives the alignment motor M253 to move the alignment plates 109a and 109b in the width direction perpendicular to the sheet discharge direction, thereby aligning the position of the sheet P in the width direction. The finisher control unit 220 repeatedly performs this series of operations on a predetermined number of sheets to be subjected to the binding processing, thereby forming a sheet bundle PA aligned on the intermediate processing tray 107 as illustrated in
Subsequently, after this alignment operation is performed, the binding unit performs the binding processing if a binding mode is selected. After that, as illustrated in
After that, as illustrated in
If the sheet stacking tray 114 is lowered and starts preventing the light from being transmitted to the tray lower limit sensor S242 during the operation, the finisher control unit 220 notifies the CPU circuit unit 200 of the image forming apparatus 900 of a full load of the sheet stacking tray 114, thereby causing the image forming apparatus 900 to stop the image formation. After that, once the sheet bundles on the sheet stacking tray 114 are removed, the sheet stacking tray 114 is raised until it starts preventing the light from being transmitted to the tray HP sensor S241, and is then lowered to allow the light to be transmitted to the tray HP sensor S241, thereby determining the sheet surface on the sheet stacking tray 114 again. With this operation, the image forming apparatus 900 resumes the image formation.
Next, control of the staple-free binding operation by the finisher control unit 220 during execution of the staple-free binding will be described with reference to a flowchart illustrated in
Then, in step ST1, the finisher control unit 220 detects the position of the cam 1027 by the cam sensor S247 illustrated in
Subsequently, in step ST5, the finisher control unit 220 determines whether to perform the binding operation. If the finisher control unit 220 determines to perform the staple-free binding (YES in step ST5), in step ST6, the finisher control unit 220 drives the staple-free binding motor M257. As the staple-free binding motor M257 is driven, the upper arm 1029 is swung by the cam 1027 about the axis 10211 in the clockwise direction. When the cam 1027 is further rotated to reach the position illustrated in
Subsequently, in step ST7, the finisher control unit 220 detects the position of the cam 1027 by the cam sensor S247. If the finisher control unit 220 determines that the cam 1027 is not located at the HP (NO in step ST8), in step ST9, the finisher control unit 220 continues driving the staple-free binding motor M257. After that, if the finisher control unit 220 determines that the cam 1027 is located at the HP by the cam sensor S247 (YES in step ST8), in step ST10, the finisher control unit 220 stops the staple-free binding motor M257. As a result, the sheet binding operation is completed. On the other hand, if the finisher control unit 220 determines not to perform the binding operation (NO in step ST5), the finisher control unit 220 ends the sheet binding operation immediately.
Then, if the surface of the lower teeth 10214 is coarser than the surface of the upper teeth 10210, the fibers of the fastened sheets are placed into a state of sticking to the lower teeth 10214. In other words, according to the present exemplary embodiment, the sheets can be intentionally stuck to the lower teeth 10214 by roughening the surface of the lower teeth 10214.
Further, in the present exemplary embodiment, as illustrated in
At this time, the detachment plate spring 10215 is elastically projected upward beyond the teeth of the lower teeth 10214, i.e., in a direction for detaching the sheets beyond the tooth tips of the lower teeth 10214 in the sheet thickness direction. Then, when the detachment plate spring 10215 is raised in this manner, the detachment plate spring 10215 pushes the sheets in the direction away from the lower teeth 10214, thereby detaching the sheets from the lower teeth 10214. Therefore, the detachment plate spring 10215 can prevent the sheets from being stuck to the lower teeth 10214.
It should be noted here that the detachment plate spring 10215 has to be disposed within a detachable region where the detachment plate spring 10215 can detach the sheets illustrated in
As illustrated in
δ=WL3/3EI
In this equation, δ represents a deflection amount, W represents a load, L represents a beam length, E represents a Young's modulus, and I represents a moment of inertia of area.
Assuming that the origin G is a fixed point and a distance in the x direction corresponds to the beam length, the deflection amount δ is proportional to the cube of the distance. In other words, an increase in the distance in the x direction leads to a cubed increase in the deflection amount δ of the sheets to be detached. Therefore, the detachment plate spring 10215 should lift up the sheets largely in the positive z direction to detach the sheets. This curve L1 also exists at a symmetric position about the tooth form, and this curve is expressed as a curve L2.
Further, as illustrated in
Then, when the binding is not performed, the tip portions 102151 of the detachment plate spring 10215 are located on an upper side relative to a top position V of protrusions of the lower teeth 10214 in the z direction as illustrated in
As described above, in the present exemplary embodiment, the detachment plate spring 10215 is provided on the lower arm 1012, and the bound sheets are pushed by the detachment plate spring 10215 in the direction for detaching the sheets from the lower teeth 10214. As a result, even when the sheets are in a state of sufficiently being fastened to one another, the sheet P can be securely detached from the lower teeth 10214 as the first tooth form. Further, the sheets can be detached without moving each of the pair of tooth forms relative to the sheets. In other words, like the present exemplary embodiment, pushing the bound sheets by the detachment plate spring 10215 can prevent the sheets from being stuck to the teeth when the sheets are bound, with the use of a small and simple structure.
In the present exemplary embodiment, the detachment plate spring 10215 is provided on the lower arm 1012. However, if the upper teeth 10210 have a coarser surface, the detachment plate spring 10215 may be provided on the upper arm 1029. In other words, the present exemplary embodiment can be realized by providing the detachment plate spring 10215 on at least one of the lower arm 1012 and the upper arm 1029, and pushing the bound sheets by the detachment plate spring 10215 in a direction for detaching the sheets from at least the one of the upper teeth 10210 and the lower teeth 10214.
In the present exemplary embodiment, the tip portions 102151 of the detachment plate spring 10215 are located at the positions offset from the region where the sheets are fastened to one another. However, the present invention is not limited thereto, and the tip portions of the detachment plate spring 10215 may be located within the region where the sheets are fastened to one another.
Next, a second exemplary embodiment of the present invention will be described as an example in which the detachment plate spring is disposed within the region where the sheets are fastened to one another.
Referring to
After that, when the upper arm 1029 is moved upward, the tip portions 102151A of the detachment plate spring 10215A are located on an upper side relative to the top position V of protrusions of the lower teeth 10214A in the z direction as illustrated in
Next, a third exemplary embodiment of the present invention will be described as an example in which the detachment plate spring is disposed within the regions where the sheets are fastened to one another and at the centers of the upper teeth and the lower teeth.
Referring to
After that, when the upper arm 1029 is moved upward, the tip portion 102151B of the detachment plate spring 10215B is located on an upper side relative to the top position V of protrusions of the lower teeth 10214B in the z direction as illustrated in
The above-described exemplary embodiments have been described based on the example in which the staple-free binding unit detaches the sheets by the detachment plate spring. However, the present invention is not limited thereto. For example, the staple-free binding unit may detach the sheets by a pushing member movable vertically and configured to be moved by being driven, instead of the detachment plate spring.
Next, a fourth exemplary embodiment of the present invention will be described as an example in which the staple-free binding unit detaches the sheets by the vertically movable pushing member, instead of the detachment plate spring.
Referring to
Further, as illustrated in
After that, according to an upward movement of the upper arm 1029, the detachment pin 10215C is raised by the solenoid 10216 so that the tip portion 102151C thereof protrudes upward relative to the top position V of protrusions of the lower teeth 10214C in the z direction as illustrated in
Alternatively, the staple-free binding unit may be configured in such a manner that the detachment pin 10215C is raised by the solenoid 10216 after the upper arm 1029 is moved upward.
Further, in the second to fourth exemplary embodiments, the detachment plate spring 10215A or 10215B, or the detachment pin 10215C is disposed only at the lower teeth. However, the present invention is not limited thereto. If the surface property of the tooth form is similar between the upper teeth and the lower teeth, a similar detachment effect can be acquired by disposing the detachment plate spring 10215A or 10215B, or the detachment pin 10215C at the upper and lower teeth.
Next, a fifth exemplary embodiment of the present invention will be described as an example in which the staple-free binding unit includes detachment wire springs disposed at the lower teeth and the upper teeth instead of the detachment plate spring, and detaches the sheets with the use of these detachment wire springs.
Referring to
In the present exemplary embodiment, the lower teeth 10214D and the upper teeth 10210D are formed by similar processing methods, and therefore there is no difference between their surface properties. Then, if there is no difference between the surface properties of the lower teeth 10214D and the upper teeth 10210D, the fibers of the bound sheets are stuck to at least one of the lower teeth 10214D and the upper teeth 10210D.
In the present exemplary embodiment, the “binding region”, where the staple-free binding unit fastens the sheets to one another, corresponds to a region indicated by a broken line in
When the binding is not performed, a tip portion 102151D of the detachment wire spring 10215D is located on an upper side relative to the top position V of protrusions of the lower teeth 10214D in the z direction as illustrated in
After that, when the upper arm 1029 is moved upward, an elastic force of the tip portion 102151D of the detachment wire spring 10215D is transmitted to the sheet P, thereby detaching the sheet P from the lower teeth 10214D as illustrated in
In the present exemplary embodiment, the detachment wire spring 10215D and the detachment wire spring 10215E are disposed at the centers of the lower teeth 10214D and the upper teeth 10210D, respectively, but the positions thereof are not limited to this example. Further, the pushing force for detaching the sheets may be increased by disposing a plurality of detachment wire springs in an arranged manner. Further, the upper teeth 10210D and the lower teeth 10214D may be formed so as to have different surface properties from each other in a similar manner to the above-described first to fourth exemplary embodiments, and the detachment wire spring may be disposed only at one of the tooth forms that has a coarser surface. Further, if the surface property of the tooth form is similar between the upper teeth 10210D and the lower teeth 10214D, like the present exemplary embodiment, a similar detachment effect can be acquired by disposing the detachment plate spring 10215, 10215A, or 10215B, or the detachment pin 10215C at the upper and the lower teeth.
As illustrated in
All of the above-described exemplary embodiments have been described based on the example in which the lower teeth are fixed and only the upper teeth are moved by the moving unit 102A. However, the respective exemplary embodiments may be configured in such a manner that the upper teeth are fixed and only the lower teeth are moved by the moving unit. Alternatively, the respective exemplary embodiments may be configured in such a manner that both the upper teeth and the lower teeth are movable and the moving unit moves them into and out of contact with each other.
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.
This application claims the benefit of Japanese Patent Application No. 2013-115584 filed May 31, 2013, which is hereby incorporated by reference herein in its entirety.
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| 2013-115584 | May 2013 | JP | national |
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| Number | Date | Country | |
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| 20140353900 A1 | Dec 2014 | US |
