Patent Application
20080001338
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the members and the like provided with the same reference signs have the same function. Therefore, duplicated descriptions of these members and the like will be abbreviated appropriately. Further, members and the like which are not necessary to be described are appropriately omitted.
At first, a sheet processing apparatus 11 provided with a sheet folding apparatus 10 according to one aspect of the present invention will be schematically described with reference to
As shown in
A sheet P on which an image is formed in the image forming apparatus 13 is discharged leftward from the image forming apparatus by the sheet-discharging roller 15 arranged near a sheet discharging opening formed in the left side surface 14 of the image forming apparatus 13. The discharged sheet P passes through an opening or sheet-receiving portion facing the sheet-discharging rollers 15 and is supplied to an inner portion of the sheet processing apparatus 11.
As shown in
(1) In the case where a processing is not performed to a sheet P on which the image is formed, the sheet P on which an image is formed is discharged to the sheet-discharging tray 16 via the conveyance path 20 extending upward in a vicinity of the sheet-discharging roller 15. Alternatively, the sheet P is discharged to the sheet-discharging tray 17 via the conveyance path 21 extending leftward and the conveyance path 22 extending upward from a halfway of the conveyance path 21. Yet alternatively, the sheet P is discharged to the sheet discharging tray 18 from the left end or the downstream end of the conveyance path 21. The sheet-discharging tray 18 can be lifted up and down, and a large amount of sheet P can be stacked thereon when the sheet-discharging tray 18 is lifted down.
(2) In the case where a stapling processing is performed, a sheet P on which an image is formed is successively discharged via the conveyance path 21, the conveyance path 23 extending downward from the halfway of the conveyance path 21, and the conveyance paths 24, 25, 26, 27 and the like shown in
(3) In the case where a center-folding processing is performed to a sheet, the sheet P on which an image is formed is supplied to the sheet folding apparatus 10 via the conveyance paths 21, 23, 26, 33 shown in
On the upstream from the holding tray 35, an aligning belt 36 is provided which is rotatable in forward and reverse directions. The aligning belt 36 is provided with a bundle lowering member 37 being disposed so as to be projected from an upper surface of the holding tray 35. On the other hand, on the downstream from the holding tray 35, there is provided an aligning belt 38 which is rotatable in forward and reverse directions. The aligning belt 38 is provided with a bundle lifting member 39 being attached so as to be projected from the upper surface of the holding tray 35.
These aligning belts 36, 38 are appropriately rotated in forward and reverse directions in accordance with a timing of a sheet P discharged to the holding tray 35 by the sheet-discharging roller 34. Accordingly, the sheets P on the holding tray 35 are aligned with respect to the conveyance direction by the bundle lowering member 37 and the bundle lifting member 39. On the other hand, with respect to the sheet width direction, the aligning is performed by a left side restricting plate and a right side restricting plate (unillustrated) which come in contact with a left end and a right end of the sheets P placed on the holding tray 35 to position the sheets P.
In such a manner as described above, the bundle of sheets aligned with respect to the conveyance direction and the sheet width direction is stapled by the second stapler 40 with a staple at its folding portion (or a portion to be folded into two-fold later) located in a substantially central position in the conveyance direction. After the center-stapling, the bundle of sheets is folded at its center by a pair of center-folding rollers 43 including center-folding rollers 41, 42, and a blade unit 44.
Specifically, after the center-stapling is performed, a folding portion (a stapling portion) of the bundle of sheets is moved by the aligning belts 36, 38 to a position corresponding to the nipping portion N of the pair of center-folding rollers 43 and the blade unit 44. Then, the bundle of sheets is pushed into the nipping portion N at its folding portion by a center-folding blade 45 (refer to
As described above, the sheet processing apparatus 11 directly discharges the sheet P being formed with an image to the sheet-discharging trays 16, 17, 18, discharges the bundle of sheets to the sheet-discharging tray 18 after the flat stapling, or discharges the bundle of sheets to the sheet-discharging tray 47 after the center-stapling and center-folding.
Next, the sheet folding apparatus 10 according to the present embodiment will be described in detail with reference to
As shown in
The pair of center-folding rollers 43 includes center-folding rollers 41, 42 each having substantially the same shape. The center-folding roller 41 (hereinafter, referred to as “first roller 41”) is a driving center-folding roller rotated with a driving force given thereto. The center-folding roller 42 (hereinafter, referred to as “second roller 42”) is a driven center-folding roller which is made to come in pressed contact with the first roller 41 to define the nipping portion N and is rotated by the first roller 41. The second roller 42 is movable in a direction separating from the first roller 41.
A detailed configuration of the pair of center-folding rollers 43 will be described. Both the first roller 41 and the second roller 42 are elongated in forward and rearward directions, and respective rotational shafts 51, 52 are rotatably supported at bearings (unillustrated) provided in a front frame 53 and a rear frame 54 of a main body frame 50. The rear frame 54 is shown in
Here, the bearings supporting the rotational shaft 51 of the first roller 41 are fixedly provided on the front frame 53 and the rear frame 54. On the contrary, the bearings supporting the rotational shaft 52 of the second roller 42 are movably supported at guide grooves 55, 56 formed respectively in the front frame 53 and the rear frame 54. In the present embodiment, orientations of the guide grooves 55, 56 i.e. orientations of lines L through rotational shafts 51, 52 of the first and rollers 41, 42 are tilted such that the left portions of the guide grooves 55, 56 are positioned lower. This tilting direction is aligned with the tilting direction of the holding tray 35 shown in
The second roller 42 is moved along the above-described guide grooves 55, 56 so that it comes in contact with the first roller 41 or separates therefrom. The second roller 42 is urged by a biasing member (unillustrated) to come in pressed contact with the first roller 41. Accordingly, the nipping portion N is defined between the first roller 41 and the second roller 42. The first roller 41 is rotated by a driving mechanism in a direction of an arrow R41. In accordance with this, the second roller 42 is drivenly rotated in a direction of an arrow R42. The pair of center-folding rollers 43 including the first and second rollers 41, 42 nip and convey a bundle of sheets which is pushed into the nipping portion N with the blade unit 44 described herebelow, thereby folding the bundle of sheets into two-fold.
Next, as shown in
As shown in
These salient portions 63, 63, 64, 64, 65, 65 are provided at positions corresponding to a sheet width of a sheet P of a kind which is frequently used. Specifically, the center-folding blade 45 pushes a folding portion of a bundle of sheets with its leading end 45a into the nipping portion N of the above-described pair of center-folding rollers 43 by pushing a vicinity of opposite ends in the sheet width direction of the bundle of sheets with these salient portions 63, 63, 64, 64, 65, 65. Accordingly, the bundle of sheets can be folded into two-fold favorably, and the center-folding blade 45 can be easily pulled out of the bundle of sheets which are folded in two-fold and nipped and conveyed at the nipping portion N. The center-folding blade 45 is supported at its base end by a plate-like holder 59.
The holder 59 includes a pair of holding plates i.e. a right holding plate 57 and a left holding plate 58. The right holding plate 57 and the left holding plate 58 are formed to have the same length as that of the above-described center-folding blade 45. The right holding plate 57 and the left holding plate 58 presses the base end of the center-folding blade 45 and are fastened with screws to hold the center-folding blade 45.
The right holding plate 57 has at its lower end a bent portion 66 oriented rightward. Further, the right holding plate 57 has notches 67, 67 at its front end and rear end, and pressing portions 68, 68 for pressing shafts 73, 73. At the notches 67, 67, there are placed shafts 73, 73 described hereinafter. Further, in vicinities of notches 67, 67, there are provided hooks 70, 70. In the case where pull springs 79 (refer to
On the other hand, the left holding plate 58 has at its lower end portion a bent portion 71 which overlays on the bent portion 66 of the above-described right holding plate 57, and has at its front end and rear end bent portions 72, 72 which are bent rightward. The shafts 73, 73 serving as a pivotal axis of the holder 59 penetrates through these bent portions 72, 72 in forward and rearward directions, and base ends of the shafts 73, 73 are located at the notches 67, 67 and fastened with screws to the left holding plate 58. Further, an intermediate portion of the shafts 73, 73 are pressed between pressing portions 68, 68 and the left holding plate 58. The first guide rollers 61, 61 are rotatably supported at respective extremity ends of the shafts 73, 73 which penetrate through the bent portions 72, 72 and projected outward.
The first guide rollers 61, 61 and the second guide rollers 62, 62 are formed to be cylindrical. The first guide rollers 61, 61 have flange-like stoppers 61a, 61a at positions close to base ends of the shafts 73, 73. The second guide rollers 62, 62 are rotatably supported by shafts 60, 60. The shafts are provided on the lower side from the first guide rollers 61, 61 in the bent portion 72 and projected outward from the bent portion 72. The guide rollers 62, 62 and the inner portions of the first guide rollers 61, 61 than the stoppers 61a, 61a are engaged with guide grooves 75, 76 which will be described hereinafter.
As shown in
The guide grooves 75, 76 are formed such that an extension of a center C of the groove width W is aligned with the nipping portion N of the above-described pair of center-folding rollers 43. In other words, a center line C is oriented in a direction substantially perpendicular to the above-described straight line L. Further, the above-described straight line L is tilted such that the line lowers leftward as described above. Thus, the guide grooves 75, 76 are tilted such that the guide grooves 75, 76 rise leftward. The above-described first guide rollers 61, 61 and the second guide rollers 62, 62 are fitted in the guide grooves 75, 76 with an appropriate clearance as described below.
As shown in
On the other hand, the second clearance W2 has a length (second length) greater than the first clearance W1. Here, “greater” means that the second clearance W2 has a length greater than the clearance which allows the second guide roller 62, 62 to roll smoothly. In other words, a play is positively provided. Accordingly, the second guide rollers 62, 62 can be moved or deviated within the groove width W of the guide grooves 75, 76.
Since the first and second clearances W1, W2 are provided as described above, the blade unit 44 (the holder 59, and the center-folding blade 45 held by the holder 59) can swing about the first guide rollers 61, 61 as a center (swing about the first guide rollers 61, 61 as a pivotal supporting point). Accordingly, the leading end 45a of the center-folding blade 45 can be moved or swung.
In the present embodiment, the blade unit 44 is pushed in a substantially oblique upper right direction by a link 92 of a crank mechanism 89 which are described below. Further, the guide grooves 75, 76 are tilted leftward as described above. Therefore, the second guide rollers 62, 62 comes in contact with guide surfaces 75b, 76b on the left side (the guide surfaces positioned on the side of the driven center-folding roller 42) in the guide grooves 75, 76 under the own weight of the blade unit 44.
Assuming that the guide surfaces 75b, 76b are reference guide surfaces, a state where the second guide rollers 62, 62 comes in contact with the reference guide surfaces is a reference posture of the blade unit 44 including the holder 59 and the center-folding blade 45. When the blade unit 44 is driven by the driving mechanism 80 in a state where there is no bundle of sheets, it is raised along the guide grooves 75, 76 while keeping the reference posture, and the leading end 45a of the center-folding blade 45 pushed into the nipping portion N. In other words, the reference posture is set so as to allow the above-described operation to be performed.
As described above, the blade unit 44 comes into the reference posture under its own weight. Therefore, when a folding portion of a bundle of sheets is pushed up into the nipping portion N of the pair of center-folding rollers 43 by the center-folding blade 45 of the blade unit 44, the blade unit 44 can be moved against a force given from the bundle of sheets to the blade unit 44.
In some cases, the reference posture of the blade unit 44 cannot be maintained assuredly under its own weight in accordance with an orientation of the guide groove 75, 76. In such cases, spring members may be provided between the front frame 53 and a part of a front end of the holder 59, or between the rear frame 54 and a part of a rear end of the holder 59 respectively. Thus, the spring members urge the blade unit 44 to keep at the reference posture.
As shown in
A torque of the motor 81 is transmitted to a gear 84 integrally formed with a pulley 82 via a driving belt 83 extending between an output shaft 81a of the motor 81 and the pulley 82. The gear 84 is in mesh with a large-diameter gear 85, and a torque of the gear 84 is transmitted via the large-diameter gear 85 at a reduced speed to a small-diameter gear 86 which is integrally formed with the large-diameter gear 85. The small-diameter gear 86 is in mesh with other large-diameter gear 87, and a torque of the small-diameter gear is transmitted via the large-diameter gear 87 at a reduced speed to other small-diameter gear 88 integrally formed with the large-diameter gear 87. A torque of the small-diameter gear 88 is transmitted to a driving gear 90 which constitutes a part of a crank mechanism 89.
The crank mechanism 89 includes a driving gear 90, a pin 91 projected outward at a position away off from a center of the driving gear 90, and a link 92 disposed between the pin 91 and a shaft 73 on the above-described blade unit 44. A similar crank mechanism 89 is provided also on the rear end of the blade unit 44 (right hand side in
Each member of the driving mechanism 80 is rotated as described herebelow when the crank mechanism 89 is at the home position, and the output shaft 81a is rotated in the direction of an arrow a. In other words, in accordance with the rotation of the output shaft 81a in the direction of the arrow a, the driving belt 83 rotates in the direction of an arrow b, the pulley 82 and the gear 84 rotate in the direction of an arrow c, the large-diameter gear 85 and the small-diameter gear 86 rotate in the direction of an arrow d, and other large-diameter gear 87 and other small-diameter gear 88 then rotate in the direction of an arrow e.
Accordingly, the driving gear 90 of the crank mechanism 89 rotates in the direction of an arrow f. The link 92 pushes the shaft 73 of the blade unit 44 in a substantially upper-right direction while the driving gear 90 rotates half the way. Further, while the driving gear 90 rotates the remaining half of the way, the blade unit 44 is moved down in a substantially lower-right direction. In accordance with these operations, the blade unit 44 including the holder 59 and the center-folding blade 45 is moved up and down, in other words, the blade unit 44 is push into the nipping portion N and moved down in accordance with the rolling (movement) of the first guide rollers 61, 61 and the second guide rollers 62, 62 along the guide grooves 75, 76.
In the state where there is no bundle of sheets, this movement is performed while the blade unit 44 is maintained at the reference posture under its own weight. Further, the leading end of the center-folding blade 45 is pushed upward about 5 mm from the straight line L in
In the sheet folding apparatus 10 having the above-described configuration, in the state where the crank mechanism 89 is at the home position, a bundle of sheets is placed on the holding tray 35 such that a folding portion (binding portion) of the bundle of sheets corresponds to the nipping portion N between the center-folding blade 44 and the pair of center-folding rollers 43 as shown in
Here, in the present embodiment, the first clearance W1 is set to have a small value, and the second clearance W2 is set to have a value greater than the first clearance W1, as described above. Therefore, the leading end of the center-folding blade 45 of the blade unit 44 can be swung about the first guide rollers 61, 61 a distance corresponding to the second clearance W2.
When the number of sheets P is small, and the thickness of the bundle of sheets is small, the blade unit 44 pushes up the folding portion or the stapling portion of the bundle of sheets at the leading end 45a of the center-folding blade 45, and inserts the same into the nipping portion N between the pair of center-folding rollers 43 while maintaining the above-described reference posture.
By the way, when the thickness of the bundle of sheets is greater as the number of sheets to be folded increase, the gap of the nipping portion N become wider owing to that the separated distance between the first roller 41 and second roller 42 increases as the thickness of the bundle of sheets is greater. This gap, in principle, can be twice as large as the thickness of the bundle of sheets. In this case, the leading end of the center-folding blade 45 is moved by the bundle of sheets toward a center of the nipping portion N, in other words, from the surface of the first roller 41 toward the second roller 42 an amount corresponding to the thickness of the bundle of sheets.
At this time, since the blade unit 44 can move a distance corresponding to the second clearance W2 as described above, the blade unit 44 as a whole follows in accordance with the movement of the center-folding blade 45, thereby pushing the bundle of sheets into the nipping portion N in a stable posture. In other words, the second clearance is secured to allow the center-folding blade 45 to move freely without any difficulty in accordance with a thickness of the bundle of sheets to be center-folded. It means that each of the second guide rollers 62, 62 has a diameter which allows the center-folding blade 45 to move. Therefore, in a case where the thickness of the bundle of sheets is small, and even in the case where the thickness is large, deviation of position, wrinkles, breakage of the bundle of sheets can be prevented from occurring.
If the above-described second clearance W2 is unnecessarily large, the posture of the blade unit 44 is likely to be unstable. Therefore, it is preferable to set the second clearance W2 such that a swing width F of the leading end 45a of the center-folding blade 45 becomes smaller than the maximum thickness of the bundle of sheets which are to be center-folded.
Further, as shown in
In the above descriptions, the present invention is described with the example where a bundle of sheets is folded at its center after being formed with image. However, the present invention may be widely applied to a case where a bundle of sheets is folded regardless of image forming, or a case where a bundle of sheet is folded into two-fold at not a center but a desirable position.
The specific embodiment described above mainly includes the following arrangements.
A sheet folding apparatus comprises: a pair of center-folding rollers including a first roller and a second roller, each roller being rotatable about an axis thereof, the first roller and the second roller being made pressed contact with each other to define a nipping portion but being separable from each other; a center-folding blade projecting toward the nipping portion for pushing a folding portion of the bundle of sheets into the nipping portion so as to allow the pair of center-folding rollers to nip and convey the folding portion to thereby fold the bundle of sheets into two-fold; a holder for holding a base end portion of the center-folding blade; a guide member including a guide groove having a pair of guide surfaces extending along a tangential direction through the nipping portion; a first guide roller and a second guide roller held by the holder and rollable in the guide groove, the first guide roller being arranged closer to the nipping portion than the second guide roller; and a driving mechanism for moving the center-folding blade to the nipping portion via the holder, wherein a first clearance between a groove width of the guide groove and a diameter of the first guide roller is a first necessity minimum length to allow the first guide roller to roll in the guide groove, and a second clearance between the groove width and a diameter of the second guide roller is a second length longer than the first necessity minimum length.
According to this arrangement, the holder is movable within a range between a position where the second guide roller comes in contact with one guide surface and a position where the second guide roller comes in contact with other guide surface, with the first guide roller as a center. At which position the holder comes into a stable posture between any one of the positions within the range is unambiguously determined in accordance with a moment applied to the center of the first guide roller. The amount of the moment is changed during the folding operation, but its direction is not changed. Thus, when the bundle of sheets has a small thickness, or when it has a great thickness, a posture of the holder and center-folding blade is not greatly changed during the folding operation. Accordingly, deviation of a folding position, wrinkles, breakage and the like which are likely to be generated when the bundle of sheets is thick can be suppressed.
In this case, it is preferable that the first roller is given with a driving force, and the second roller which comes in pressed contact with the first roller to define the nipping portion is rotated by the first roller. The second roller is movable in a direction of separating from the first roller.
In the above-described arrangement, it is preferable that the guide surface positioned on the side of the driven center-folding roller serves as a reference guide surface, and when the second guide roller comes in contact with the reference guide surface, the holder and the center-folding blade are in a reference posture in which a leading end of the center-folding blade directs to the nipping portion.
According to this arrangement, the second guide roller comes in contact with the reference guide surface in the reference posture of the holder and center-folding blade. Accordingly, a second clearance is secured between the second guide roller and the other guide surface. Therefore, when the bundle of sheets has a great thickness, and the folding portion of the bundle of sheets is pushed into the nipping portion by the center-folding blade, the driven center-folding roller is separated from the driving center-folding roller. Further, the center-folding blade is also moved toward the driven center-folding roller an amount corresponding to the thickness of the bundle of sheets. Accordingly, the second guide roller is moved toward the other guide surface about the first guide roller as a center. In other words, the second guide roller is moved in a direction of making the second clearance be narrow. The amount of movement of the second roller becomes greater as the thickness of the bundle of sheets becomes greater, and the second clearance becomes that amount narrower. In other words, the second clearance allows the center-folding blade to follow with respect to a thickness of the bundle of sheets.
In the above-described arrangement, it is preferable that the holder and the center-folding blade come into the reference posture under their own weight. According to this arrangement, the holder and center-folding blade can be easily moved by following a force given thereto.
Further, it is preferable that a biasing member for biasing the holder and the center-folding blade to the reference posture is provided. According to this arrangement, the biasing member urges the holder and the center-folding blade to stably maintain the reference posture of the same.
In the above-described arrangement, it is preferable that the holder includes a shaft for rotatably supporting the first guide roller, and the driving mechanism transmits a driving force to the holder via the shaft. According to this arrangement, the action of the center-folding blade and the holder is freely made. In other words, a transmission of a driving force does not interfere with the action of the center-folding blade and the holder.
In this case, it is preferable that the driving mechanism transmits a driving force to the shaft via a crank mechanism. According to this arrangement, a favorable movement can be given to the center folding blade which presses the bundle of sheets into the nipping portion.
In the above-described arrangement, it is preferable that the second clearance is smaller as a ratio of a distance between a center of the first guide roller and a center of the second guide roller against a distance between a leading end of the center-folding blade and a center of the first guide roller becomes smaller.
According to this arrangement, the second clearance and a swing width of a leading end of the center-folding blade are made substantially proportional. Thus, the second clearance is made small when the distance ratio is small, thereby preventing the swing width of the center-folding blade from becoming greater than the necessity minimum.
In this case, it is preferable that the second clearance is set such that a swing width of the center-folding blade is smaller than the thickness of the bundle of sheets to be folded.
According to this arrangement, the defect can be prevented which occurs when a swing width of the center-folding blade is greater than the thickness of the bundle of sheets. Specifically, the defect can be prevented which a posture of the center-folding blade and the holder becomes stable when the second guide roller does not come in contact with the other guide surface.
A sheet folding apparatus comprises: a pair of center-folding rollers including a first roller and a second roller, each roller being rotatable about an axis thereof, the first roller and the second roller being made pressed contact with each other to define a nipping portion but being separable from each other; a center-folding blade projecting toward the nipping portion for pushing a folding portion of the bundle of sheets into the nipping portion so as to allow the pair of center-folding rollers to nip and convey the folding portion to thereby fold the bundle of sheets into two-fold; a holder for holding a base end portion of the center-folding blade; a guide member including a guide groove having a pair of guide surfaces extending along a tangential direction of the nipping portion; a first guide roller and a second guide roller held by the holder and rollable in the guide groove, the first guide roller being arranged closer to the nipping portion than the second guide roller; and a driving mechanism for moving the center-folding blade to the nipping portion via the holder. The center-folding blade is movable about the first guide roller supported at the guide surface in accordance with a thickness of a bundle of sheets to be folded at its center, and the second guide roller has a roller diameter operable to allow the movement of the center-folding blade.
A sheet processing apparatus comprises: a sheet folding apparatus for performing a center-folding processing to a bundle of sheets; a sheet-receiving portion for receiving supply of the sheet; a sheet-discharging portion for discharging a processed sheet; and a conveyance path for allowing the sheet supplied from the sheet-receiving portion to be conveyed to the sheet-discharging portion via the sheet folding apparatus. The sheet folding apparatus includes: a pair of center-folding rollers including a first roller and a second roller, each roller being rotatable about an axis thereof, the first roller and the second roller being made pressed contact with each other to define a nipping portion but being separable from each other; a center-folding blade projecting toward the nipping portion for pushing a folding portion of the bundle of sheets into the nipping portion so as to allow the pair of center-folding rollers to nip and convey the folding portion to thereby fold the bundle of sheets into two-fold; and a pivotal shaft for swingably supporting the center-folding blade so as to allow a projecting leading end of the center-folding blade to be swung in accordance with a thickness of a bundle of sheets to be folded at its center.
This application is based on Japanese Patent application serial no. 2006-180966 filed in Japan Patent Office on Jun. 30, 2006, the contents of which are hereby incorporated by reference.
Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-180966 | Jun 2006 | JP | national |
