Patent Grant
11274013
The present invention relates to a sheet folding apparatus configured to perform a sheet folding process.
Hitherto, sheet folding apparatuses have been known, which are used in image forming apparatuses such as copiers and printers and which fold a sheet along center line to form two parts, or along two lines on the same side to form three parts, or along two lines at opposite sides, respectively, to form a Z-held sheet.
JP 2002-068583 A and JP 2008-207924 A, for example, disclose sheet folding apparatuses which comprise a sheet-folding roller pair configured to fold a sheet, a sheet-feeding roller pair configured to feed the sheet to the sheet-folding roller pair, a small roller provided at the front of the sheet-feeding roller pair, a pushing member configured to move to the first position to push the small roller onto one of the sheet folding rollers and to the second position remote from the sheet-folding roller pair, and a space located in front of the sheet-folding roller pair.
Any sheet folding apparatus of such a configuration has a single-folding mode and a Z-folding mode. In the single-folding mode, the sheet feeding rollers transport the sheet to a position where the front edge of the sheet hangs in a space. The pushing member is then moved from the second position to the first position, moving the sheet to a position where a prescribed part of the hanging sheet is pressed onto one of the folding rollers. Then, the folding roller pair is driven. That part of the sheet, which is pushed by the small roller, is thereby moved and nipped by the pair of sheet folding rollers. Since said part of the sheet is nipped by the pair of sheet folding rollers, the sheet is thereby held double.
Next, in the Z-folding mode, the sheet folding rollers are stopped while the folding-roller pair is nipping the front edge of the sheet, and the sheet feeding rollers are driven. The sheet therefore slackens, forming a loop in the space. When the loop is formed at the sheet feeding rollers, the sheet feeding rollers are stopped, and the pushing member moves from the second position to the first position. The small roller therefore pushes a prescribed part of the sheet loop from outside thereof, toward the sheet-folding roller pair. A prescribed part of the sheet is therefor moved to a position, where said part of the sheet is pressed onto one of the sheet folding rollers. After the pushing member is moved to the first position, the folding-roller pair is driven again. That part of the sheet, which is pushed onto the folding-roller pair by the small roller, therefore moves and nipped by the pair of sheet folding rollers, forming a second Z-folding line. Thereafter, the sheet folding rollers are driven further. Then, the loop of the sheet in the space becomes smaller gradually, and that part of the loop, which corresponds to the first Z-folding line, is nipped by the sheet-folding roller pair. The sheet is thereby Z-folded, making first Z-holding line.
In the sheet folding apparatuses disclosed in JP 2002-068583 A and JP 2008-207924 A, however, the prescribed part of the sheet pressed onto one of the sheet folding rollers by the small roller warps at its downstream side. This warping of the sheet is not always constant, inevitably changing the position where the sheet is drawn into the sheet folding rollers and nipped between them. Consequently, the position (folding line) where the sheet is single-folded differs from the position (second folding line) where the sheet is Z-folded. Further, that part of the sheet, which is pressed onto the small roller to Z-fold the sheet, is pressed to one of the sheet folding rollers via the front-edge part of the sheet. Inevitably, the sheet slips on the next sheet as it is moved, and the first folding position (first folding line) changes. If the folding position so changes, any sheet folded will have a degraded appearance and will differ from the other sheet in terms of folded state.
This invention uses, in order to reduce the change of the sheet-folding position, transport rollers, folding rollers, a pushing member, and a guide section. The pushing member is provided between the transport rollers and the folding rollers, and guides a prescribed part of the sheet in a space to the folding-roller pair. The guide section guides any sheet guided by the pushing member to the folding rollers.
A preferred embodiment of this invention will be described, with reference to the accompanying drawings.
[Image Forming System]
[Image Forming Apparatus]
The image forming apparatus A is of the type that forms an image on a sheet by using an electrostatic printing mechanism known in the art. The apparatus A has a sheet feeding section 2, an image forming section 3, a sheet ejecting section 4, and a control section (not shown), all provided in an apparatus housing 1. On the housing 1, an image reading section 5 composed of a scanner unit is provided. On the image reading section 5, an automatic document-sheet feeding section 6 is provided, integral with the image reading section 5. The image forming apparatus A according to this embodiment is a so-called internal sheet-ejecting type, and a transport relay unit 7 is arranged in a large front U-shaped sheet-ejecting space defined among the image forming section 3, sheet ejecting section 4 and image reading section 5 shown in
The sheet feeding section 2 has sheet supplying cassettes 2a and 2b, which hold sheets of one size and sheets of another size, respectively. The cassettes 2a and 2b can be inserted into, and can be removed from, the housing 1. The sheet feeding section 2 holding sheets, on which images will be formed, feeds a sheet of the size designated by the control section, from the cassette into a sheet supplying passage 8. In the sheet supplying passage 8, registering rollers 9 are provided. The sheet registered, at its front edge, by the registering rollers 9 is supplied, at prescribed timing, to the image forming section 3 which is arranged downstream.
The image forming section 3 has an electrostatic drum 10, and further has a printing head, a developing device, a transfer charger and the like, which are arranged around the electrostatic drum 10. The printing head is composed of, for example, a laser-beam emitter, and forms an electrostatic latent image on the electrostatic drum 10. The developing device applies toner ink to the electrostatic latent image, forming a toner image. The transfer charger transfers the toner image to the sheet. The sheet having the toner image transferred to it is transported to a fixing device 11. The fixing device 11 fixes the toner image by heating and with pressure, and the sheet is transported into the sheet ejecting passage 12 provided in the sheet ejecting section 4.
The sheet ejecting passage 12 branches, at the downstream end, into a first sheet-ejecting passage 13 and a second sheet-ejecting passage 14. The second sheet-ejecting passage 14 is located below the first sheet-ejecting passage 13. The first and second sheet-ejecting passages 13 and 14 are connected to a first ejection port 15 and a second ejection port 16, respectively, which open to the sheet-ejecting space.
The sheet ejecting section 4 may have a sheet circulating passage (not shown). The sheet circulating passage connects the sheet ejecting passage 12 to the sheet supplying passage 8 at, for example, a position upstream the registering rollers 9. The sheet supplied from the image forming section 3 and therefore having an image is switched back into the sheet circulating passage by rotating the sheet ejecting rollers provided in the sheet ejecting passage 12. The sheet is thereby turned upside down and is then transported again to the image forming section 3. Images can therefore be formed on both sides of the sheet.
As illustrated in
The first relay unit 17 has a first relay passage 20 in it. The first relay passage 20 has a first sheet inlet port 21 and a first sheet outlet port 22. The first sheet inlet port 21 is connected to the first ejection port 15 of the sheet ejecting section 4. The first sheet outlet port 22 is arranged and opens to the sheet-ejecting space, above the sheet-ejected tray 19. At the first relay passage 20, transport rollers are provided near the first sheet outlet port 22 and are driven by a motor incorporated in the first relay part 17. The sheet having an image formed on it and transported from the sheet ejecting section 4 through the first sheet-ejecting passage 13 is transported by the transport rollers, passes through the first relay passage 20 and is transported onto the sheet-ejected tray 19.
The second relay part 18 incorporates a second relay passage 23. The second relay passage 23 has second sheet inlet port 24, which is connected to the second ejection port 16 of the sheet ejecting section 4. The second sheet outlet port 25 of the second relay passage 23 opens, almost in flush with the left side surface of the apparatus housing 1, and is connected to the sheet inlet port of the sheet folding apparatus C as will be described later. In the second relay passage 23, a plurality of rollers are arranged. These rollers are driven by a motor incorporated in the second relay part 18, and transport the sheet. The sheet transported from the sheet ejecting section 4 via the second sheet-ejecting passage 14 and having an image formed on it is transported by the transport rollers to the sheet folding apparatus C through the second relay passage 23.
The image reading section 5 comprises a platen 26 configured to hold a document sheet, a reading carriage 27 configured to move along the platen, and an optical reading unit 28 composed of, for example, a CCD device. The reading carriage 27 scans the document sheet placed on the platen 26, optically reading the document sheet. The optical image thereby generated is opto-electrically converted to image data by the optical reading unit 28. The document-sheet feeding section 6 automatically feeds a document sheet from a sheet supply tray 29 to the platen 26.
In the image forming apparatus A configured as described above, the image reading section 5 reads a document sheet fed from the document-sheet feeding section 6, and the image forming section 3 forms an image on the basis of the image data read by the image reading section 5. If the sheet having the image formed on it need not be folded by the sheet folding apparatus C or be post-processed by the sheet post-processing apparatus B, it is transported from the sheet ejecting section 4 through the first sheet-ejecting passage 13, then passes through the first relay passage 20, and is transported onto the sheet-ejected tray 19 provided in the sheet-ejecting space. If the sheet having the image formed on it need be folded and/or post-processed, it is transported from the sheet ejecting section 4 through the second sheet-ejecting passage 14, then passes through the second relay passage 23 and is sent to the sheet folding apparatus C.
[Sheet Post-Processing Apparatus]
As shown in
The first ejected-sheet tray 105 is arranged below the sheet-outlet port 108 of the second transport path 102, which opens in said side of the housing 100. Any sheet sent from the sheet folding apparatus C is transported from the first transport path 101 onto the second transport path 102 and ejected through the sheet-outlet port 108 onto the first ejected-sheet tray 105 if the staple unit ST1 does not perform a stapling process and/or any other post-process.
The sheet-outlet port 109 of the third transport path 103 is positioned above the binding-process tray 104, opposing the sheet-mounting surface of the binding-process tray 104. To be stapled together by the staple unit ST1, the sheets sent from the sheet folding apparatus C are transported from the first transport path 101 to the third transport path 103 and are ejected from the sheet-outlet port 109 of the path 103 onto the sheet holding surface of the binding-process tray 104. The sheets accumulated on the binding-process tray 104 are stapled together, forming a sheet bundle, by the staple unit ST1. The sheet bundle is transported from the binding-process tray 104 to the second ejected-sheet tray 106 located downstream the binding-process tray 104.
[Overall Configuration of the Sheet Folding Apparatus]
As shown in
Further, an additional-folding mechanism 36 may be provided, as an optional component, near the sheet-outlet port 32b of the transport path 32. It has been well known to anyone skilled in the art that in a folding apparatus such as the sheet folding apparatus C, an additional-folding mechanism for pressing the sheet at a position downstream the sheet-folding section is used in order to fold the sheet reliably at the sheet-folding position.
[Registering-Roller Pair]
The registering-roller pair 33 is composed of a driving roller 33a and a driven roller 33b, which are arranged above and below the transport path 32, respectively. The driven roller 33b has its surface pressed to the surface of the driving roller 33a by, for example, an appropriate spring unit (not shown). Therefore, the driven roller 33b is rotated if the driving roller 33a is driven by a registering motor which will be described later.
The sheet transported from the transport relay unit 7 of the image forming apparatus A by an ejecting roller pair 37 provided near the second sheet outlet port 25 has its front edge abut on a nip part 38 of the registering-roller pair 33 not rotating. The sheet therefore is registered at its front edge. The sheet having its front edge so registered is transported toward the folding-roller pair 34 through the transport path 32, as the registering-roller pair 33 is driven at a prescribed timing.
In an another embodiment, the registering-roller pair 33 can be replaced by ejecting rollers (equivalent to the ejecting roller pair 37) which eject the sheet from the image forming apparatus A to the sheet folding apparatus C. This reduces the number of components constituting the sheet folding apparatus C, lowering the manufacturing cost and rendering the apparatus C shorter in the sheet transporting direction. In this case, the ejecting roller pair 37 should better have a function of aligning the sheet transported to the transport path 32, at its front edge, as described above.
[Folding-Roller Pair]
The folding-roller pair 34 consists of an upper folding roller 34a and a lower folding roller 34b provided across the transport path 32. The rollers 34a and 34b are pressed to each other, at their surfaces, by an appropriate spring unit (not shown), nip the front edge and folding line of each sheet transported from the registering-roller pair 33 and fold the sheet. Further, the rollers 34a and 34b pressed to each other are driven, in unison, by a folding-roller drive motor described later, and rotate to transport the sheet.
The folding-roller pair 34 is arranged above the tangential line 39a passing a nip part 39 where the rollers press each other, positioning the nip 38 of the registering-roller pair 33 above the tangential line 39a. In the embodiment of
[Transport Path]
As shown in
The sheet inlet path 41 has an upper inlet guide 41a and a lower inlet guide 41b which are arranged one above the other and extend in the sheet transport direction and which guides the front edge of the sheet to the nip part 38 of the registering-roller pair 33. The upper inlet guide 41a greatly flares out upwards from the point near the registering-roller pair 33 toward the inlet side to provide a space large enough to allow the sheet to warp and form a loop as it is transported from the upstream side to the ejecting roller pair 37, as the front edge of the sheet abuts on the nip part 38 of the registering-roller pair 33 and is thereby aligned.
As shown in
As described above, the tangential line 38a passing the nip part 38 of the registering-roller pair 33 and the tangential line 39a passing the nip part 39 of the registering-roller pair 34 extend parallel to each other and are arranged one above the other. Therefore, the upper transport guide 45 has a first horizontal part 45a horizontally extending downstream along the tangential line 38a, a second horizontal part 45b horizontally extending upstream along the tangential line 39a, and an inclining part 45c extending downward from the upstream side to the downstream side as if connecting the tangential lines 38a and 39a.
As shown in
In another embodiment, the part connecting the inclining part 45c and the second horizontal part 45b may be curved. In this case, the protrusion 47 is shaped, protruding almost downward from the center path 42. The part connecting the inclining part 45c and the first horizontal part 45a may be curved similarly. In still another embodiment, the second horizontal part 45b and inclining part 45c of the upper transport guide 45 may be separate members, and may constitute the protrusion 47.
In this embodiment, as shown in
The lower transport guide 46 has a first lower guide part 46a and a second lower guide part 46b. The first lower guide part 46a extends in the downstream direction, from the registering-roller pair 33 to a prescribed position in the sheet transporting direction. The second lower guide part 46b extends in the upstream direction, from the folding-roller pair 34 to a prescribed position in the sheet transporting direction. The first lower guide part 46a and the second lower guide part 46b are secured to the housing 31, defining, between them, a large space 48 extending in the sheet transporting direction. The space 48 between the first lower guide part 46a and the second lower guide part 46b can be opened and closed by the pushing plate 35 which can horizontally move toward or retreats from the nip part 39 of the folding-roller pair 34 as will be described later.
As shown in
The first lower guide part 46a has a first horizontal guide part 51a and a first inclining guide part 51b. The first horizontal guide part 51a extends horizontally from the registering-roller pair 33 to the downstream side, while opposing the first horizontal part 45a of the upper transport guide 45. The first inclining guide part 51b extends downward, from the first horizontal guide part 51a, almost parallel to the middle part of the inclining part 45C of the upper transport guide 45. The downstream end of the first inclining guide part 51b defines the hanging start position of sheet when the space 48 is opened. In this embodiment, the lower end of the first inclining guide part 51b is located above the tangential line 39a extending through the nip part 39 of the folding-roller pair 34.
The second lower guide part 46b is composed of a second horizontal guide part 52a (first transport guide member), a second inclining guide part 52b (second restriction guide member), and a vertical guide part 52c (first restriction guide member). The second horizontal guide part 52a horizontally extends from the folding-roller pair 34 in upstream direction. The second inclining guide part 52b inclines downwards, from the second horizontal guide part 52a. The vertical guide part 52c extends downward, almost vertically, from the second horizontal guide part.
The second horizontal guide part 52a cooperates with the second horizontal part 45b of the upper transport guide 45, and guides the front edge of the sheet to the nip part 39 of the folding-roller pair 34, while restricting the sheet at both side in the thickness direction, namely the vertical direction. The second inclining guide part 52b inclines toward the loop-forming space 50, to guide the sheet hanging in the loop-forming space 50, into the nip part 39. The second inclining guide part 52b cooperates with the vertical guide part 52c, isolating the sheet hanging in the loop-forming space 50 from the folding-roller pair 34, while maintaining a sufficient size of the loop-forming space. That is, the second inclining guide part 52b and the vertical guide part 52c are arranged in the loop-forming space 50 located below the space 48 of the lower transport guide 46, and functions as a loop guide unit 53 for restricting the upstream part of the sheet loop hanging in the loop-forming space 50. In this embodiment, the second horizontal guide part 52a, second inclining guide part 52b and vertical guide part 52c of the second lower guide part 46b are provided on one lower transport guide member. Instead, they may be provided on three members, respectively.
While the pushing plate 35 remains in the retreat position (described later), the sheet transported from the registering-roller pair 33 to the center path 42 may move beyond the downstream end of the first inclining guide part 51b. In this case, the sheet transported from the registering-roller pair 33 to the center path 42 hang down linearly, first at its front edge, through the open space 48 into the loop-forming space 50. If the space 48 is opened while the front edge of the sheet remains nipped by the folding-roller pair 34 and the folding-roller pair 34 are stopped, the sheet in the center path 42 is curved and hangs down, in the shape of a loop, through the space 48 into the loop-forming space 50.
In other words, the center path 42 is composed of a first passage part which transports the sheet from the registering-roller pair 33, a second passage part which can selectively connect the center path 42 to the loop-forming space 50, and a third passage part which guides the sheet to the nip part 39 of the folding-roller pair 34. The first to third passage parts are practically connected in the sheet transporting direction by the upper transport guide 45 composed of the first and second upper transport guide members. At the lower surface of the sheet, the first passage part is composed of the first lower guide part 46a secured in position, and the third passage part is composed of the second lower guide part 46b secured in position. By contrast, the second passage part is composed of the space 48 which can be opened and closed by moving the pushing plate 35.
In another embodiment, the first passage part may be composed of only a horizontal guide part, not using the first inclining guide part 51b. As shown in
The sheet outlet path 43 has an upper transport guide 43a and a lower transport guide 43b which are arranged in the sheet transporting direction and one above the other, in order to guide any sheet folded to the sheet-outlet port 32b. In front of the sheet-outlet port 32b, an additional-folding mechanism 36 is provided. The mechanism 36 has a plurality of rolling members that move on the lower transport guide 43b in, for example, a direction which intersects with the sheet widthwise direction, thereby to further fold the sheet that has been folded already.
[Pushing Plate]
As show in
While the pushing plate 35 remains at the retread position, the space 48 of the lower transport guide 46 fully opens, and the center path 42 therefore has its second passage part opened to the loop-forming space 50 located below. The sheet in the center path 42 can therefore hang down in the loop-forming space 50.
At the guiding position indicated by the broken lines 35′, the pushing plate 35 completely closes the space 48 of the lower transport guide 46, opposes the upper transport guide 45 in the vertical direction at the same time, and forms a part of the lower transport guide 46. The sheet is guided from the center path 42 into the second passage part, without hanging down in the loop-forming space 50. Then, the sheet is transported from the first passage part to the third passage part.
While remaining at the pushing position indicated by broken lines 35″, the pushing plate 35 enters the gap between the second horizontal part 45b of the upper transport guide 45 and the second horizontal guide part 52a of the second lower guide part 46b in the third passage part. This pushing position is a position where the pushing plate 35 moves the folding line of the sheet to the nip part 39 of the folding-roller pair 34.
The pushing plate 35 is moved to the retread position and between the guiding position and the pushing position, by the pushing-plate drive motor M3 provided in a drive mechanism shown in
[Drive Mechanism in the Sheet Folding Apparatus]
The drive mechanism 58 for driving the registering-roller pair 33 comprises a registering-roller drive motor MT1, a drive pulley P1 mounted on the shaft of the registering-roller drive motor MT1, a driven pulley P2 mounted on one end of the roller shaft 61 of the driving roller 33a, and a timing belt TB1 wrapped around both pulleys P1 and P2. The drive force of the registering-roller drive motor MT1 is transmitted from the shaft of the registering-roller drive motor MT1 to the driving roller 33a through the transmission mechanism composed of the drive pulley P1, timing belt TB1 and driven pulley P2.
A drive mechanism 59 for driving the folding rollers 34 comprises a folding-roller drive motor MT2, a driving pulley P3 mounted on the shaft of the motor MT2, a driven pulley P4 mounted on the roller shaft 56 of the lower folding roller 34b, and a timing belt TB2 wrapped around both pulleys P3 and P4. The drive mechanism 59 further comprises gears Z1 and Z2. The gear Z1 is mounted coaxially on the roller shaft 56, and can rotate as the roller shaft 56 is driven. The gear Z2 is mounted coaxially on the roller shaft 55, and can rotate as the roller shaft 55 of the upper folding roller 34a is driven.
The drive force of the folding-roller drive motor MT2 is transmitted from the shaft of the motor MT2 to the lower folding roller 34b through the transmission mechanism composed of the driving pulley P3, timing belt TB2 and driven pulley 4. Further, the drive force of the folding-roller drive motor MT2 is transmitted from the roller shaft 56 having the driven pulley P4 to the upper folding roller 34a through the gears Z1 and Z2 which are in mesh with each other. The upper folding roller 34a and the lower folding roller 34b therefore rotate at the same time in opposite directions, and can cooperate to transport the sheet nipped by the rollers 34a and 34b in the sheet transporting direction.
The drive mechanism 60 for driving the pushing plate 35 comprises the pushing-plate drive motor M3, a driving pulley P5, a rotary shaft 62, a driven pulley P6, a timing belt TB3, a first rack-pinion mechanism 63, and a second rack-pinion mechanism 64. The driving pulley P5 is mounted on the shaft of the pushing-plate drive motor M3. The rotary shaft 62 extends in the sheet widthwise direction. The driven pulley P6 is mounted on one end of the rotary shaft 62. The timing belt TB3 is wrapped around both pulleys P5 and P6. The first rack-pinion mechanism 63 is arranged at one end of the rotary shaft 62 and located inner than the driven pulley P6. The second rack-pinion mechanism 64 is provided at the other end of the rotary shaft 62.
The first rack-pinion mechanism 63 has a first pinion 63a and a first rack 63b. The first pinion 63a is mounted on one end of the rotary shaft 62, positioned more inner than the driven pulley P6, and can rotate as the shaft 62 is driven. The first rack 63b is provided on one end of the pushing plate 35 and meshes with the first pinion 63a. Similarly, the second rack-pinion mechanism 64 has a second pinion 64a and a second rack 64b. The second pinion 64a is mounted on the other end of the rotary shaft 62, and can rotate as the shaft 62 is driven. The second rack 64b is provided on the other end of the pushing plate 35 and meshes with the second pinion 64a. The first and second racks 63b and 64b are arranged so that the pushing plate 35 synchronously moves in the same direction to move the first and second pinions 63a and 64a in the horizontal direction.
The drive force of the pushing-plate drive motor M3 is transmitted from the shaft thereof to the first pinion 63a and second pinion 64a through the transmission mechanism composed of the driving pulley P5, timing belt TB3 and driven pulley P6. Therefore, the first and second racks 63b and 64b move synchronously in the same direction, and move the pushing plate 35 in the horizontal direction.
[Control System in the Sheet folding Apparatus]
The first detection sensor S1 is arranged in front of the registering-roller pair 33 of the sheet inlet path 41, and detects the front edge of the sheet transported from the image forming apparatus A through the sheet-inlet port 32a. The second detection sensor S2 is arranged in front of the folding-roller pair 34 of the center path 42, and detects the front edge of the sheet transported from the registering-roller pair 33 to the folding-roller pair 34. The third detection sensor S3 detects the position of the pushing plate 35 moving to the retreat position, the guiding position or the pushing position. The outputs of the first to third detection sensors S1 to S3 are supplied to the control section 120 in real time.
The control section 120 is connected to the control section 121 of the image forming apparatus A, by the sheet post-processing apparatus B. The control section 121 is connected to the input section (not shown) and the display section (not shown), both incorporated in the console panel D of the image forming apparatus A. The data, such as the sheet type the user has set on the console panel D of the image forming apparatus A, and the data, such as the sheet-folding mode in which to operate the sheet folding apparatus C are transmitted from the control section 121 to the control section 120 through the sheet post-processing apparatus B.
The CPU of the control section 120 executes the program stored in a ROM, and controls the drive motors MT1, MT2 and MT3 and an additional-folding motor MT4 for driving the additional-folding mechanism 36. That is, the CPU of the control section 120 executes the program stored in the ROM, and controls the drive motors MT1, MT2, MT3 and MT4. On the basis of the outputs from the first to third detection sensors 51 to S3 and the various data items received from the control section 121 of the image forming apparatus A, the drive motors MT1 to MT4 are controlled, thereby controlling the sheet transportation in the transport path 32 and the sheet-folding process in the sheet folding apparatus C.
The control section 120 can transmit, in real time, the information about the sheet transportation and sheet folding, both performed in the sheet folding apparatus C, to the control section 121 of the image forming apparatus A through the post-processing apparatus B. If the information received from the control section 120 contains alarm data or undesirable data representing sheet-transportation error or insufficient sheet folding, the alarm or the undesirable data can be displayed at, for example, the display unit of the console panel D.
The sheet folding apparatus C according to the present embodiment can fold a sheet along two parallel lines along the sheet transporting direction to achieve the so-called Z-folding.
[Sheet-Folding Process in the Sheet Folding Apparatus]
How the sheet folding apparatus C folds a sheet will be described hereinafter. A Z-folding mode of folding a sheet along two lines and a non-folding mode of not folding a sheet at all are preset in the sheet folding apparatus C. Before starting the image-forming process in the image forming apparatus A, the user determines which process, the image-forming process or the sheet-folding process, should be performed. To perform the sheet-folding process, the sheet-folding mode is selected and input at the console panel D. The sheet-folding mode is stored, as information about the sheet subject to folding process, in the control section 121 of the image forming apparatus A.
How the sheet folding apparatus C operates will be explained briefly, with reference to the flowchart of
If the sheet information acquired from the control section 121 of the image forming apparatus A contains the instruction of performing the selection of the folding mode or the instruction of performing the sheet-folding process (Y in Step ST03), the operation proceeds to Step ST04, performing the sheet folding process. Alternatively, the sheet information acquired may not contain the instruction of performing the selection of the folding mode or the instruction of performing the sheet-folding process or may contain the instruction of not performing the sheet-folding process. If this is the case, the process goes to Step ST07, and no sheet folding is performed.
In Step ST07 (performing sheet non-folding), the pushing plate 35 is positioned in the guiding position (indicated by broken lines 35′), and the registering-roller pair 33 and the folding-roller pair 34 are rotated. Therefore, the sheet transported from the image forming apparatus A passes through the transport path 32 without being folded and transported to the sheet post-processing apparatus B.
The sheet-folding process starting in Step ST04 is performed in three steps, i.e., the registering process (Step ST04) performed by the registering-roller pair 33, the loop forming process (Step ST05) performed by the folding-roller pair 34, and the folding-line forming process (Step ST06) performed by the pushing plate 35 and folding-roller pair 34. In the registering process, the sheet transported into the sheet folding apparatus C is registered at its front edge, eliminating the sheet skew (sheet inclination). In the loop forming step, the front edge of the sheet is looped in order to make a folding line. In the folding-line forming step, the folding-roller pair 34 forms a folding line on the looped sheet.
The processes performed in Steps ST04 to ST06 will be described below in greater detail.
[Registering Process]
The control section 120 waits until a prescribed time passes after the first detection sensor 51 detects the front edge of the sheet transported into the sheet inlet path 41 and is thereby turned on while the rotation of the registering-roller pair 33 is being halted (Y in Step ST10). The prescribed time is long enough to abut the sheet, at its front edge, on the nip part 38 of the registering-roller pair 33, thereby to align the front edge of the sheet. The prescribed time is preset in the control section 120 on the basis of, for example, the results of experiments.
When the prescribed time elapses (Y in Step ST11), the control section 120 actuates a register loop counter (i.e. software-operated timer counter), which starts measuring time (Step ST12). Then, the control section 120 drives the registering-roller drive motor MT1, rotating the registering-roller pair 33 (Step ST13).
As the registering-roller pair 33 is driven, the sheet is transported to the folding-roller pair 34 through the transport path 32 as is illustrated in
[Loop Forming Process]
The loop forming process is performed in, for example, the sequence illustrated in the flowchart of
The process of retreating the pushing plate 35 is performed in, for example, the sequence shown in the flowchart of
When the third detection sensor S3 arranged below the first lower guide part 46a detects the detection flag of the pushing plate 35 and is turned on (Y in Step ST51), the pushing-plate drive motor M3 is stopped (Step ST52). The pushing plate 35 is thereby moved to the retreat position shown in
Next, the control section 120 starts driving the registering-roller drive motor MT1 when the second detection sensor S2 detects the front edge of the sheet in Step ST21, and keeps driving the registering-roller drive motor MT1 until the motor MT1 is driven by a first preset drive value (Y in Step ST23). Then, the control section 120 stops the folding-roller drive motor MT2 (Step ST24). The first preset drive value is equivalent to the value by which the registering-roller drive motor MT1 should be driven to move the sheet to the position where the front edge of the sheet is nipped at the nip part 39 of the folding-roller pair 34. The drive amount of the registering-roller drive motor MT1 can be the rotation value of the motor (i.e., the number of rotations, rotation angle or rotation time of the rotor shaft) or the distance the sheet is transported by the registering-roller pair 33, namely the rotation value of the driving roller 33a (i.e., the number of rotations, rotation angle or rotation time of the roller shaft 61).
The sheet is therefore held, with its front edge nipped at the nip part 39 of the folding-roller pair 34. Thereafter, the registering-roller drive motor MT1 is kept driven. The registering-roller pair 33 therefore keeps rotating, transporting the sheet further. As a result, that part of the sheet, which is upstream of the folding-roller pair 34, hangs down into the loop-forming space 50 through the space 48, forming a loop FL. The loop FL will be processed to make a folding line. Thereafter, the loop FL grows as the registering-roller pair 33 transports the sheet. The sheet nipped, at its front edge, by the registering-roller pair 33, bulges into the loop-forming space 50, as described above, before the pushing plate 35 is retreated. Hence, the sheet is smoothly and stably bent, forming a loop in the loop-forming space 50, without excessively increasing the load on the registering-roller drive motor MT1.
In this embodiment, the distance (i.e., transport distance) the sheet is transported until the front edge of the sheet moves from the position where it is detected by the second detection sensor S2 to the position 10 mm ahead the nip part 39 of the folding-roller pair 34 is converted into the drive value of the registering-roller drive motor MT1, which corresponds to the distance, and this value is used as the first preset drive value mentioned above.
In the sheet folding apparatus C, the part of the foldable sheet, at which the sheet will be folded and which is identified from, for example, the distance from the front edge of the sheet in the sheet transporting direction is predetermined from the size and orientation (lengthwise or widthwise) of the sheet. The prescribed count value equivalent to said part of the sheet is preset in the register loop counter. After the folding-roller drive motor MT2 is stopped in Step ST24, the count value of the register loop counter that starts operating in Step ST11 is increased to the prescribed count value (Y in Step ST25). Then, the operation goes to the next folding-line forming process (i.e., Step ST06).
[Folding-Line Forming Process]
After the sheet is warped to a prescribed degree in the loop-forming space 50, the control section 120 performs the folding-line forming process. The folding-line forming process is performed, for example, in the sequence shown in the flowchart of
First, the control section 120 drives the pushing-plate drive motor M3 (Step ST53), moving the pushing plate 35 in horizontal direction toward the folding-roller pair 34. The pushing plate 35 moves toward the nip part 39 of the folding-roller pair 34, while its front edge is pushing that part of the loop FL which will form a folding line which is the second line as seen from the front edge of the sheet. While the pushing plate 35 is moving, the control section 120 controls the registering-roller drive motor MT1 and the pushing-plate drive motor M3, moving the pushing plate 35 at the same speed as the sheet is transported by the registering-roller pair 33 so that the loop FL pushed by the front end of the pushing plate 35 may not change in position and the pushing plate 35 may move at the same speed v1 as the sheet is transported by the registering-roller pair 33. Driven by the pushing-plate drive motor M3, the pushing plate 35 moves to the pushing position 35″ to a position immediately before the nip part 39.
This embodiment is characterized in that the control section 120 changes the speed at which the pushing plate 35 moves by the time when it reaches the pushing position 35″, namely from a high speed to a low speed. That is, as shown in
More specifically, the control section 120 determines whether the pushing-plate drive motor M3 has been driven by a second preset value, thereby finding whether the pushing plate 35 has moved to the guiding position 35′ (Step ST54). The second preset value is the drive value that enables the pushing-plate drive motor M3 to move the pushing plate 35 at the speed v1 to a position immediately before the second horizontal guide part 52a. The second preset value can be the rotation value of the motor MT2 (i.e., number of revolutions, angle of rotation or rotation time) or the distance the pushing plate 35 should be moved.
This embodiment is further characterized in that the control section 120 controls the folding-roller drive motor MT2 in order to start driving the folding-roller pair 34 at low speed at the time immediately before the pushing plate 35 reaches the pushing position 35″.
More specifically, the folding-roller drive motor MT2 is driven (Step ST56) at time t2 when the drive value of the pushing-plate drive motor M3 reaches a third preset value (Y in Step ST 55) after the moving speed of the pushing plate 35 is switched to the speed v2, so that the folding-roller pair 34 may rotate at the same speed as the sheet-transporting speed v2 of the registering-roller pair 33 as shown in
Next, when the driven value of the pushing-plate drive motor M3 reaches a fourth preset value at time t3 (Y in Step ST57), the control section 120 stops the pushing-plate drive motor M3, assuming that the pushing plate 35 has moved to the pushing position 35″ (Step ST58).
When the pushing plate 35 moves to the pushing position 35″, its front edge reaches, as is shown in
Thus, the pushing plate 35 and the folding-roller pair 34 are simultaneously driven between time t1 when the pushing plate 35 transports the folding part of the sheet, at which second folding line 203 will be made, to a prescribed position before the pushing position 35″ (i.e., guiding position 35′ in this embodiment), and time t2 when the pushing plate 35 transports the folding part to the pushing position 35″. Therefore, the sheet is not pushed by the pushing plate 35, and is transferred to the folding-roller pair 34. Since the sheet is not pushed into the space P illustrated in
Even after the pushing-plate drive motor M3 is stopped in Step ST58, the control section 120 keeps driving the registering-roller pair 33 and the folding-roller pair 34 at the speed v2. Therefore, as shown in
The driven value of the registering-roller drive motor MT1 reaches a fifth preset value at time t4 (Y in Step ST59) after the second folding line is made. At this time t4, the control section 120 controls the registering-roller drive motor MT1 and the folding-roller drive motor MT2 so that the registering-roller pair 33 and the folding-roller pair 34 may transport the sheet at high speed v1 (Step ST60).
After the pushing-plate drive motor M3 is stopped in Step ST58, the registering-roller drive motor MT1 is driven by a sixth preset value (Y in Step ST61). Then, the control section 120 drives the folding-roller drive motor MT2 (Step ST62). The sixth preset value is the drive value by which the registering-roller drive motor MT1 is driven to rotate the registering-roller pair 33, thereby to transport the sheet continuously even after the pushing-plate drive motor M3 is stopped in Step ST58, until the part FP 2 of the sheet is taken into the nip part 39 of the folding-roller pair 34.
When the folding-roller pair 34 is driven by the folding-roller drive motor MT2, that part of the sheet, at which the second folding line will be made, is taken into the nip part 39 of the folding-roller pair 34 as shown in
After driving the folding-roller drive motor MT2 in Step ST62, the control section 120 performs a plate-retreating process, moving the pushing plate 35 from the pushing position 35″ back to the above-mentioned retreat position, not to prevent the sheet from being taken into the nip part 39 of the folding-roller pair 34 (Step ST63). The plate-retreating process is performed in the same way as in loop-forming process explained with reference to
That is, in the state of
At this time, the space 48 between the first lower guide part 46a and the second lower guide part 46b is fully opened and the second passage part of the center path 42 is connected to the loop-forming space 50 located below. The loop FL can therefore be continuously and smoothly taken into the nip part 39 of the folding-roller pair 34 from the nipping start as illustrated in
Even after the pushing plate 35 is moved to the retreat position, the folding-roller pair 34 is kept driven. Therefore, as shown in
As the sheet is so transported, the loop FL gradually becomes smaller in the loop-forming space 50. The loop FL then enters the third passage part of the center path 42, and is squeezed, from above and below, by the first horizontal part 45a of the upper transport guide 45 and the second inclining guide part 52b of the second lower guide part 46b. The loop therefore becomes a thin loop extending in the sheet transporting direction. The loop FL further moves into the gap between the second horizontal part 45b and the second horizontal guide part 52a of the second lower guide part 46b, and is folded double, from above and below, at a part FP1 at the rear edge (upstream edge) of the sheet, where a first folding line will be made.
The sheet having the folded part FP1, so bent as described above, is transported without slipping or changes in position, with respect to the upstream part of the sheet overlapped on it. The sheet is then pressed and bent at the nip part 39 of the folding-roller pair 34. The sheet can therefore have a first folding line (line 202 shown in
A Z-folded sheet SH is thereby obtained, which has an inner folding line 202 and an outer folding line 203 as illustrated in
Next, the first detection sensor S1 detects the rear edge of the sheet being transported by the registering-roller pair 33 and the folding-roller pair 34, and is turned off (Y in Step ST64). Then, the control section 120 performs a guiding process, moving the pushing plate 35 from the retreat position to the guiding position 35′ (Step ST65). At this time, the folding loop FL has already passed from the folding-roller pair 34. Therefore, even if the pushing plate 35 is moved to the guiding position 35′, no troubles will be made in the process of transporting the sheet through the center path 42 or in the process of forming a folding line by using the folding-roller pair 34.
The above-mentioned guiding process is performed in the sequence shown in, for example, the flowchart of
The seventh preset value is the drive value of the pushing-plate drive motor M3, which is required to move the pushing plate 35 from the retreat position to the guiding position 35′. The pushing plate 35 therefore closes the gap between the first and second lower guide parts 46a and 45b. Then, the rear edge of the sheet is guided through the center path 42 onto the upper surface of the pushing plate 35, and the sheet is transported straight toward the folding-roller pair 34. The rotation value of the pushing-plate drive motor M3 (i.e., number of revolutions, angle of rotation or rotation time) can be used as the drive value of the pushing-plate drive motor M3.
Next, the second detection sensor S2 may detect the rear edge (i.e., upstream edge) of the sheet passing through the center path 42, and may be turned off (Y in Step ST66). At this time, the control section 120 starts measuring the drive value of the folding-roller drive motor MT2. When the drive value of the motor MT2 reaches a preset motor-stopping value (Y in Step ST67), the registering-roller drive motor MT1 and the folding-roller drive motor MT2 are stopped (Step ST68).
The motor-stopping value mentioned above is a drive value of the folding-roller drive motor MT2, which is large enough to allow the rear edge of the sheet to pass through the nip of the folding-roller pair 34. The registering-roller pair 33 and the folding-roller pair 34 can therefore be stopped without making any trouble in transporting the sheet through the sheet-outlet port 32b to the sheet post-processing apparatus B, terminating the process of Z-folding the sheet.
[Modification 1]
The first modification of the embodiment described above will be described below. In the first modification, a loop guide unit 70 different from the loop guide unit 53 is provided.
As shown in
The first loop guide 71a of the loop guide unit 70 inclines upward from the upstream end of the second lower guide part 46b, gradually leaving the second horizontal part 45b of the upper transport guide 45 in the vertical direction. The second loop guide 71b of the loop guide unit 70 extends upstream almost horizontally from the lower end of the first loop guide 71a. In this embodiment, the lower end of the first loop guide 71a extends in the sheet transporting direction to a position near the downstream end of the first lower guide part 46a in the sheet transporting direction, and the upstream end of the second loop guide 71b extends to a position below the registering-roller pair 33. Since the loop guide unit 70 is so configured, the loop-forming space 50 is relatively shallow in the height direction intersecting at right angles with the sheet transporting direction, and is relatively long in the sheet transporting direction, below the center path 42.
Thereafter, the folding-roller pair 34 are stopped, and the pushing plate 35 is moved to the retreat position. The front edge of the sheet is thereby nipped by the folding-roller pair 34. When the registering-roller pair 33 transports the sheet, while the folding-roller pair 34 is stopped, the sheet in the center path 42 is bent into the loop-forming space 50, in the form of a loop, through the space 48, as is illustrated in
The more the sheet hangs, forming a loop, in the loop-forming space 50, the more it bends along the slope from the folding-roller pair 34 to the first loop guide 71a of the loop guide unit 70. Then, as shown in
Immediately below the registering-roller pair 33 and the pushing plate 35 in the retreat position, a first partitioning member 73 is provided and secured to the housing 31. The first partitioning member 73 partially defines the upper part of the loop-forming space 50, and positions the sheet or the sheet loop, in the loop-forming space 50, from the registering-roller pair 33 and the pushing plate 35. In
Moreover, a second partitioning member 74 is secured to the housing 31 and extends to the upstream side from the loop guide unit 70 and first partitioning member 73. The second partitioning member 74 defines the loop-forming space 50 in the sheet transporting direction, and prevents the sheet or the loop from extending from the loop-forming space 50, upstream in the sheet transporting direction.
The first partitioning member 73 can not only position the sheet and the loop in the loop-forming space 50, away from the registering-roller pair 33 and the pushing plate 35, but can also restrict the sheet loop in the sheet transporting direction, from above in the height direction. In this case, the first partitioning member 73 can be said to constitute a part of the loop guide unit 70. The first partitioning member 73 and the loop guide unit 70 can be secured to the housing 31 separately, or can be formed integral to each other.
Like the first partitioning member 73, the second partitioning member 74 can be arranged to restrict the sheet loop in the sheet transporting direction, from above in the height direction, in the loop-forming space 50. If this is the case, the second partitioning member 74 and the loop guide unit 70 can be secured to the housing 31 separately, or can be formed integral to each other.
In the embodiment described above, the registering-roller pair 33 transports the sheet downstream, while the folding-roller pair 34 is nipping the sheet and stopping the sheet, and a sheet loop is thereby formed. Alternatively, the folding-roller pair 34 may transport the sheet upstream in the reverse direction (namely, toward the registering-roller pair 33, while the registering-roller pair 33 is nipping the sheet and stopped, thereby to make a sheet loop.
That is, the folding loop FL further extends smoothly from the first loop guide 71a along the second loop guide 71b to the upstream side in the sheet transporting direction in accordance with the transport distance of the sheet reversely transported by the folding-roller pair. The loop FL is therefore elongated in the loop-forming space 50 regulated by the loop guide 70, is relatively thin in the height direction and is relatively long in the sheet transporting direction.
[Modification 2]
The second modification of the embodiment described above will be described below. In the second modification, a driven roller 80 is provided at the second horizontal part 45b of the upper transport guide 45.
The driven roller 80 is secured to the second horizontal part 45b of the upper transport guide 45, and has a shaft 80a that can freely rotate. The driven roller 80 is biased downwards by a spring 81. As shown in
The function of the driven roller 80 will be explained. The pushing plate 35 pushes the sheet at the part where the second folding line (line 203 shown in
It is desirable that two driven rollers 80 should be provided, respectively at the sides of the sheet, spaced apart in the widthwise direction of the sheet. In the modification 2, two driven rollers 80 are arranged respectively at the sides of the sheet of minimum size that can be processed.
The preferred embodiments of this invention has been described above. However, the invention is not limited to the embodiments. Needless to say, the invention can be reduced to practice, by changing or modification, within its technical scope.
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-230527, filed Dec. 10, 2018, Japanese Patent Application No. 2018-245126, filed Dec. 27, 2018 and Japanese Patent Application No. 2019-094929, filed May 21, 2019, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2018-230527 | Dec 2018 | JP | national |
| JP2018-245126 | Dec 2018 | JP | national |
| JP2019-094929 | May 2019 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 8256757 | Imazu | Sep 2012 | B2 |
| 8590880 | Imazu | Nov 2013 | B2 |
| 9168762 | Nakamura | Oct 2015 | B2 |
| Number | Date | Country |
|---|---|---|
| H05-319686 | Dec 1993 | JP |
| 2001-171907 | Jun 2001 | JP |
| 2002-068583 | Mar 2002 | JP |
| 2005-067741 | Mar 2005 | JP |
| 2008-207924 | Sep 2008 | JP |
| 2008-247531 | Oct 2008 | JP |
| 2012-111567 | Jun 2012 | JP |
| 2016-182998 | Oct 2016 | JP |
| 2016-216185 | Dec 2016 | JP |
| 2017-128441 | Jul 2017 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20200180896 A1 | Jun 2020 | US |
