Patent Application
20200180897
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 at a predetermined position. The sheet folding process includes folding a sheet along a center line to form two parts, folding a sheet along two lines on the same side to form three parts, and folding a sheet along two lines at opposite sides, respectively, to form a Z-held sheet.
A sheet folding apparatus is known, which comprises a sheet-feeding roller pair provided upstream of a horizontal upper guide plate, a sheet-folding roller pair provided downstream of the horizontal upper guide plate, and a sheet deflection guide member (i.e., a pushing member) provided upstream from the sheet-folding roller pair (e.g., JP 2002-068583 A). This apparatus is configured such that the sheet deflection guide member moves from a second position which is retreated obliquely downward, upstream from the sheet-folding roller pair, to a first position where the front edge of the sheet is brought to a location near the sheet take-in part of the sheet-folding roller pair, allowing a prescribed end of the sheet hanging down in a space in front of the sheet-folding roller pair to be taken into the sheet take-in part, whereby the sheet is held double or Z-folded.
Additionally, there is proposed a sheet processing apparatus which comprises a sheet-transporting roller pair provided upstream of a sheet transport path constituted by an upper guide member and a lower guide member facing each other, a sheet-folding roller pair provided downstream of the sheet transport path, and a pressing member (i.e., a pushing member) which is freely movable between a first position and a second position, the first position functioning to block a cutaway portion formed in the lower guide plate, the second position being retreated obliquely downward from the upstream side of the cutaway portion, and, with the above structure, the sheet processing apparatus also performs sheet material bending process including the double-folding and Z-folding (e.g., JP 2005-067741 A). The pressing member moves, from the second position, along the upper guide member, abutting on the sheet material hanging down from a cutaway portion opened between the sheet-feeding roller pair and the sheet-folding roller pair, to the first position, while pressing, with its front-end roller, the sheet material, and guides the bending position of the sheet material to a nip between the sheet-folding rollers, which bend the sheet material by their rotation.
In the above apparatuses disclosed in patent documents 1 and 2, in the case of Z-folding of sheet, while the sheet-folding roller pair is nipping the front edge (downstream edge in the sheet transporting direction) of the sheet and being stopped, the sheet-feeding roller pair continues transporting the sheet from upstream side to make a loop of sheet in the space opened at a lower part of the transport path. However, since the sheet is transported horizontally and linearly from the sheet-feeding roller pair toward the sheet-folding roller pair, when the sheet is made to curve into a loop shape, the transport load applied on the sheet-feeding roller pair temporarily increases due to the stiffness of the sheet. In addition, the foregoing configuration may cause the sheet to be curved toward the transport path, opposite to the space, depending on the transporting conditions.
Particularly, in the sheet-feeding roller pair, the sheet may slip due to the increase of transport load, and as a result, the sheet-folding position which the pushing member is pressed against may change and the change will not allow the sheet to be folded along an accurate folding line.
The present invention relates to a sheet folding apparatus, including: a feeding-roller pair, a loop-forming space which is provided downstream from the feeding-roller pair, for forming a sheet loop, a pushing member for pushing the sheet formed in a loop shape, a folding-roller pair for folding the sheet by nipping a prescribed part of the sheet pushed by the pushing member, and a path which is provided between the feeding-roller pair and the folding-roller pair and guides the sheet coming from the feeding-roller pair toward the direction of the loop-forming space.
A preferred embodiment of this invention will be described, with reference to the accompanying drawings.
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-electronically 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.
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.
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.
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.
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 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
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 transporting 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 illustrated 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 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 constituted by a single lower transport guide 46 having a second horizontal guide part 52a, a second inclining guide part 52b and a vertical guide part 52c. 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 in upstream direction, 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 of the folding-roller pair 34. 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 50.
While the pushing plate 35 remains in the retreat position, the sheet transported from the registering-roller pair 33 to the 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 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 path 42 is curved and hangs down, in the shape of a loop, through the space 48 into the loop-forming space 50.
It is favorable to arrange the protrusion 47 of the upper transport guide 45 almost at the center of the space 48 along the sheet transporting direction, and hence, in one embodiment, as shown in
Due to the stiffness of sheet, it is difficult, as compared to a center portion of the space 48, to make the sheet curve downward at a location near the downstream end of the first lower guide part 46a and at a location near the upstream end of the second horizontal guide part 52a of the second lower guide part 46b, when viewing the path 42 in the sheet transporting direction. When the protrusion 47 is arranged as illustrated in
According to another embodiment, the protrusion 47, as illustrated in
So arranged as illustrated in
The path 42 is substantially continuous, in the sheet transporting direction, above the upper surface of the sheet, due to the upper transport guide 45 composed of the first and second upper transport guide members. Below the lower surface of the sheet, the path 42 is composed of the fixed first lower guide portion 46a, fixed second lower guide portion 46b and the pushing plate 35 having been moved.
In another embodiment, the path 42 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.
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 path 42 therefore has its second passage part opened to the loop-forming space 50 located below. The sheet in the 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 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 motor MT3 provided in a drive mechanism shown in
The drive mechanism 58 for driving the registering-roller pair 33 comprises a transport motor MT1, a drive pulley P1 mounted on the shaft of the transport 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 transport motor MT1 is transmitted from the shaft of the transport 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 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 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 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 motor MT3, 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 motor MT3. 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 motor MT3 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.
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 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 control section 120 is connected to the transport motor MT1, folding motor MT2 and pushing motor MT3. When providing the additional-folding mechanism 36, the control section 120 is also connected to an additional-folding drive motor MT4. On the basis of the outputs from the first to third detection sensors S1 to S3 and the various data items received from the control section 121 of the image forming apparatus A, the motors MT1 to MT3 and, optionally, 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.
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 Steps ST04 to ST06, 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 in Steps ST04 to ST06 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 with reference to
The control section 120 is turned on when the first detection sensor S1 detects the front edge of the sheet transported into the sheet inlet path 41 while the rotation of the registering-roller pair 33 is being stopped (Y in Step ST10), and, in response, a folding loop counter (not shown) starts measuring time (Step ST11). When a prescribed time elapses (Y in Step ST12) after the start of the measurement, the control section 120 drives the transport motor MT1 (Step ST13), rotating the registering-roller pair 33 (Step ST13).
The prescribed time in Step ST12 is a time length required to form, in the sheet inlet path 41, a loop necessary or large enough to align the front part of the sheet when the front edge of the sheet abuts on the nip part 38 of the registering roller pair 33. For example, this time can be predetermined based on a test result or the like and preset in the control section 120.
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
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 motor MT3 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 transport motor MT1 when the second detection sensor S2 detects the front edge of the sheet in Step ST21, and keeps driving the transport 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 motor MT2 (Step ST24). The first preset drive value is equivalent to the value by which the transport 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.
As shown in
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 transport motor MT1, which corresponds to the distance, and this value is used as the first preset drive value mentioned above. The drive amount of the transport 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).
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 folding loop counter. After the folding motor MT2 is stopped in Step ST24, the count value of the folding 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).
The folding-line forming process is performed, for example, in the sequence shown in the flowchart of
The pushing process is performed in, for example, the sequence shown in the flowchart of
The sheet, pushed by the pushing plate 35, moving downstream through the third passage part of the path 42 is restricted, at its upper part (bent upward over the pushing plate 35), from above, by the second horizontal part 45b of the upper transport guide 45, while its lower part (bent downward with respect to the pushing plate 35) is restricted from below by the second horizontal guide part 52a of the second lower guide part 46b, in a state that its leading end part upstream from the nip part 39 of the folding roller pair 34 is held between the second horizontal part 45b and the second horizontal guide part 52a. The sheet can therefore be bent at the folding position pushed by the pushing plate 35, at which the sheet will be folded to form the second folding line 203 (in
When the driven value of the pushing motor MT3 reaches a second preset value (Y in Step ST54), the control section 120 stops the pushing motor MT3 (Step ST55), whereby the front edge of the pushing plate 35 enters, as is shown in
As described above, by making the pushing plate 35 advance to a gap between the upper transport guide 45 and the second lower guide part 46b, the sheet is provisionally folded by being forcedly bent, at the folding position, one upon the other in the vertical direction. After the provisional folding, the sheet is nipped by the folding roller pair 34 at the folding position. This prevents the sheet from opening along the second folding line and hence can provide a neatly folded sheet.
The second preset value is the drive value that enables the pushing motor M3 to move the pushing plate 35 to the pushing position 35″ from the retreated position. The drive value of the pushing motor MT3 can be the rotation value of the motor (i.e., the number of rotations, rotation angle or rotation time of the rotor shaft).
After the pushing motor MT3 is stopped in Step ST58, the transport motor MT1 is driven by a third preset value (Y in Step ST31). Then, the control section 120 drives the folding motor MT2 (Step ST32). The third preset value is the drive value by which the transport motor MT1 is driven to rotate the registering-roller pair 33, thereby to transport the sheet continuously even after the pushing motor MT3 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 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 motor MT2 in Step ST32, 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 ST33). 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 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 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, in the sheet inlet path 41, 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 ST34). Then, the control section 120 performs a guiding process, moving the pushing plate 35 from the retreat position to the guiding position 35′ (Step ST35). 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 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 fourth preset value is the drive value of the pushing motor MT3, 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 space 48 between the first and second lower guide parts 46a and 46b. Then, the rear edge of the sheet is guided through the 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 motor MT3 (i.e., number of rotations, angle of rotation or rotation time of the rotary shaft) can be used as the drive value of the pushing motor MT3.
Next, the second detection sensor S2 may detect the rear edge (i.e., upstream edge) of the sheet passing through the path 42, and may be turned off (Y in Step ST36). At this time, the control section 120 starts measuring the drive value of the folding motor MT2. When the drive value of the motor MT2 reaches a preset motor-stopping value (Y in Step ST37), the transport motor MT1 and the folding motor MT2 are stopped (Step ST38).
The motor-stopping value mentioned above is a drive value of the folding 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.
According to another embodiment of the present invention, the sheet can be transported straight to the inclined part (second passage) 45c of the path 42 from the registering-roller pair 33. Also, the inclined part (second passage) 45c of the path 42 can be a curved passage. Further, the inclined part (second passage) 45c and the second horizontal part 45b, of the path 42 can be configured by a continuous curved passage.
The modification shown in
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. 2018-230528, filed Dec. 10, 2018, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-230528 | Dec 2018 | JP | national |
