Sheet transport device and image forming system

Abstract

It prevents damage to the seats and the occurrence of seat jams. [Solution] A sheet conveying device for conveying a sheet S is provided with a first guide 610 that forms a conveying path for conveying the sheet S in a first direction. The first guide 610 has a plurality of first ridge-shaped portions 610a that are spaced apart from each other in the sheet width direction W, extend in a direction intersecting the sheet width direction W, and have first contact portions that contact and guide the sheet S being conveyed, and a plurality of inclined portions 618 that are each positioned between at least some of the plurality of first ridge-shaped portions 610a and adjacent first ridge-shaped portions 610a in the sheet width direction W, and are inclined to move away from the virtual plane 610v formed by connecting the plurality of first ridge-shaped portions 610a toward the conveying center of the conveying path.

Description

Technical Field

[0004] ,

[0005] , ,

[0001] The present invention relates to a sheet conveying device for conveying a sheet and an image forming system to which the same is applied.

Background Art

[0002] Conventionally, a sheet conveying device for conveying a sheet in an image forming apparatus has a guide portion that forms a conveyance path for conveying the sheet. If the guide portion is planar over the entire width direction of the sheet, the conveyance resistance of the sheet increases and the sheet may stick. For this reason, as the guide portion, a plurality of rib-shaped guides arranged parallel to the sheet conveyance direction and spaced apart in the sheet width direction are known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0006] One aspect of the present invention is a sheet conveying device for conveying sheets, comprising a first guide that forms a conveying path for conveying sheets in a first direction, wherein the first guide has a plurality of first ridge-like portions that are spaced apart from each other in a width direction perpendicular to the first direction, extend in a direction intersecting the width direction, and have first contact portions that contact and guide the sheet being conveyed, and a plurality of first inclined portions that are each arranged between at least some of the plurality of first ridge-like portions and adjacent first ridge-like portions in the width direction, and are inclined to move away from a virtual plane formed by connecting the plurality of first ridge-like portions toward the conveying center of the conveying path.

[0007] Another aspect of the present invention is an image forming system characterized by comprising an image forming apparatus for forming an image on a sheet, and the above-mentioned sheet transport apparatus. [Effects of the Invention]

[0008] According to the present invention, damage to the sheet and the occurrence of sheet jams can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing an image forming system according to an embodiment. [Figure 2] This is a cross-sectional view showing an inversion module according to an embodiment. [Figure 3] This is a cross-sectional view showing the second inversion section of the inversion module according to the embodiment. [Figure 4] This figure shows the second reversal section, where (a) is a perspective view according to the embodiment, (b) is a plan view thereof, and (c) is a plan view according to a comparative example. [Figure 5]This is a plan view showing the reversal guide section of a comparative example, where (a) is an arrangement in which the first guide expands toward the second direction, and (b) is an arrangement in which the first guide expands toward the first direction. [Figure 6] This is a side view of the first guide as seen from the sheet transport direction, where (a) is an embodiment and (b) is a comparative example. [Figure 7] This is a side view showing the first guide according to the embodiment. [Figure 8] This is a plan view showing the first guide according to the embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to Figures 1 to 8. In this embodiment, the case in which the image forming system is applied to the inkjet recording system 1 is described. Figure 1 is a schematic diagram showing an example of the general configuration of the inkjet recording system 1. This inkjet recording system 1 is a sheet-fed inkjet recording system that produces a recording material by forming an ink image on a sheet S using two liquids, a reaction liquid and an ink. As shown in Figure 1, the inkjet recording system 1 consists of a feeding module 100, a print module 200, a drying module 300, a fixing module 400, a cooling module 500, an inversion module 600, and an discharge module 700. The cut sheet S supplied from the feeding module 100 is transported along the transport path, processed in each module, and discharged in the discharge module 700. In this embodiment, the sheet is a recording material and includes paper such as sheets and envelopes, plastic films such as overhead projector sheets (OHP), cloth, etc. In this embodiment, the sheet transport direction Df is positioned so that it is in the left-right direction of the inkjet recording system 1. The right side is denoted as the right direction R, the left side as the left direction L, the front side as the front direction F, the back side as the rear direction B, the top side as the up direction U, and the bottom side as the down direction D. The front-to-back direction perpendicular to the sheet transport direction is denoted as the sheet width direction W, which is an example of the width direction.

[0011] The feeding module 100 is connected to the print module 200 and transports sheets to supply sheets to the print module 200, and transfers sheets between the print module 200 and the feeding module 100. The feeding module 100 has a first feeding unit 111, a second feeding unit 112, and a third feeding unit 113 as a sheet feeding unit that houses and feeds sheets S. The first feeding unit 111 has a first housing section 111a that houses sheets S and a first feeding section 111b that feeds sheets S from the first housing section 111a. The second feeding unit 112 has a second housing section 112a that houses sheets S and a second feeding section 112b that feeds sheets S from the second housing section 112a. The third supply unit 113 has a third storage section 113a for storing sheets S, and a third feeding section 113b for feeding sheets S from the third storage section 113a. The first storage section 111a, the second storage section 112a, and the third storage section 113a are each capable of storing multiple sheets and are configured to be pull out towards the front of the device. The sheets S are separated in the first storage section 111a, the second storage section 112a, and the third storage section 113a by the first feeding section 111b, the second feeding section 112b, and the third feeding section 113b, and fed one sheet at a time to be transported to the print module 200. Note that the supply unit is not limited to three units, and may have one, two, or four or more units. The feeding module 100 will be described later.

[0012] The print module 200 is an example of an image forming apparatus and includes a pre-image registration correction unit (not shown), a print belt unit 220, and a recording unit 230, which transport the sheet S. The sheet S transported from the feed module 100 has its tilt and position corrected by the pre-image registration correction unit and is transported to the print belt unit 220. The recording unit 230 is positioned opposite the print belt unit 220 with respect to the transport path. The recording unit 230 performs a recording process (printing) on ​​the transported sheet S from above using a recording head to form an image. Multiple recording heads are arranged along the transport direction. In this embodiment, in addition to the four colors Y (yellow), M (magenta), C (cyan), and Bk (black), there are a total of five line-type recording heads corresponding to the reaction solution. Note that the number of colors is not limited to four, and the number of recording heads is not limited to five. The inkjet method can employ a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS element, etc. Each color of ink is supplied to the recording head from an ink tank (not shown) via an ink tube. The sheet S printed in the recording unit 230 is transported by a print belt unit 220, ensuring clearance with the recording head. The sheet S printed in the recording unit 230 is scanned for image misalignment and color density by an inline scanner (not shown) located downstream of the recording unit in the sheet transport direction. The detection results are used to correct the printed image.

[0013] The drying module 300 includes a decoupling section 320, a drying belt unit 330, and a hot air blowing section 340. It reduces the liquid content of the ink applied to the sheet S by the recording section 230 of the print module 200, thereby improving the adhesion between the sheet S and the ink. The sheet S printed by the recording section 230 of the print module 200 is transported to the decoupling section 320 located upstream of the sheet transport direction in the drying module 300. In the decoupling section 320, the sheet S can be transported from above by air pressure and belt friction, and by weakly holding and transporting the sheet S on the belt, it prevents the sheet S on the print belt unit 220, which forms the ink image, from shifting. The drying belt unit 330 is located below the belt, and the hot air blowing section 340 is located above the belt, facing each other across the belt. The sheet S transported from the decoupling section 320 is transported by suction in the drying belt unit 330, and at the same time, the ink-applied surface is dried by hot air from the hot air blowing section 340. In addition to the method of applying hot air, the drying method may also be configured by combining a method of irradiating the surface of the sheet S with electromagnetic waves (such as ultraviolet or infrared rays) or a conductive heat transfer method using contact with a heating element.

[0014] The fixing module 400 has a fixing belt unit 410. The fixing belt unit 410 has an upper belt unit and a lower belt unit, and the ink can be fixed to the sheet S by passing the sheet S conveyed from the drying module 300 between the heated upper belt unit and the lower belt unit.

[0015] The cooling module 500 has multiple cooling units 510 and cools the high-temperature sheet S that has been transported along the sheet transport path from the fixing module 400. The cooling units 510 are configured to cool the sheet S by drawing in outside air into the cooling box with a fan, increasing the pressure inside the cooling box, and blowing air from nozzles formed in the transport guide onto the sheet S. The cooling units 510 are positioned both above and below the transport path to cool the sheet S from both sides.

[0016] Further, the cooling module 500 has a conveyance path switching unit 520, and can switch the conveyance path of the sheet S according to whether the sheet S is conveyed to the inversion module 600 or to the duplex conveyance path used during duplex printing. During duplex printing, the sheet S is conveyed to the conveyance path below the cooling module 500. In this case, from the cooling module 500, it is further conveyed along the duplex conveyance paths of the fixing module 400, the drying module 300, the printing module 200, and the feeding module 100. A first inversion unit 420 for inverting the front and back of the sheet S is provided in the duplex conveyance path of the fixing module 400. Then, again, it is conveyed from the feeding module 100 to the pre-image registration correction unit, the print belt unit 220, and the recording unit 230 of the printing module 200, and is printed by the recording unit 230.

[0017] The inversion module 600 is an example of a sheet conveyance device that conveys the sheet S, has a second inversion unit 640, can invert the front and back of the conveyed sheet S, and can change the front and back orientation of the discharged sheet S. The discharge module 700 has a top tray 720 and a stacking unit 750, and stacks the sheets S conveyed from the inversion module 600 in an aligned manner.

[0018] [Inversion Module] Next, the configuration of the inversion module 600 will be described using FIG. 2. FIG. 2 is a schematic cross-sectional view showing the inversion module 600. The inversion module 600 has a conveyance path 604, and an entrance roller pair 601 and an exit roller pair 605 arranged on the conveyance path 604. The sheet S is carried into the entrance roller pair 601 from the cooling module 500, passes through the conveyance path 604, and is discharged from the exit roller pair 605.

[0019] Further, the inversion module 600 has a second inversion unit 640 that branches from the conveyance path 604 to invert the front and back of the sheet. The second inversion unit 640 has a branch path 641, an inversion path 642, an intermediate path 643, a confluence path 603d, a first switching unit 602, a second switching unit 606, and a third switching unit 607.

[0020] The branch path 641 is a path that branches from the conveyance path 604 and rejoins the conveyance path 604 again. The first switching unit 602 is provided at the branching portion of the conveyance path 604 and the branch path 641, and switches the conveyance destination of the sheet between the conveyance path 604 and the branch path 641 by rotation. The inversion path 642 is a path that branches from the branch path 641. The second switching unit 606 is provided at the branching portion of the branch path 641 and the inversion path 642, and switches the conveyance destination of the sheet between the branch path 641 and the inversion path 642 by rotation. The intermediate path 643 is a path that branches from the inversion path 642 and rejoins the branch path 641. The third switching unit 607 is provided at the branching portion of the inversion path 642 and the intermediate path 643, and switches the conveyance destination of the sheet between the inversion path 642 and the intermediate path 643 by rotation. Note that the branching point between the inversion path 642 and the intermediate path 643 is the nip portion formed by the inversion roller 608.

[0021] When the user designates a change in the front and back orientation of the sheet S to be discharged to the discharge module 700, the tip of the first switching unit 602 rotates upward. The sheet S is carried into the inlet roller pair 601 from the cooling module 500 and is conveyed to the second inversion unit 640 under the guidance of the first switching unit 602. On the other hand, when the user does not designate a change in the front and back orientation of the sheet S to be discharged to the discharge module 700, the first switching unit 602 rotates downward, and the sheet S is guided to the conveyance path 604 and discharged from the outlet roller pair 605 to the discharge module 700.

[0022] FIG. 3 is a detailed view of the second inversion unit 640. The sheet S conveyed to the second inversion unit 640 is conveyed through the branch path 641. The second switching unit 606 rotates to a position where it guides the sheet to the inversion path 642 side, and the third switching unit 607 rotates to the first position (lower side) where it guides the sheet in the inversion path 642. Thereby, the sheet is guided to the inversion roller 608 via the second switching unit 606 and the third switching unit 607.

[0023] The reversing roller 608 switches the sheet transport direction between the first direction D1 and the second direction D2, which is opposite to the first direction D1, by reversing its direction of rotation. When the sheet transport direction is the second direction D2 (rightward R), the reversing roller 608 stops rotating after the upstream end of the sheet has passed the downstream end of the third switching unit 607. The third switching unit 607 rotates to the upper second position, and the reversing roller 608 rotates in the opposite direction. The sheet S is transported from the intermediate path 643 to the branch path 641 with the sheet transport direction set to the horizontal first direction D1 (leftward L) by the reversing roller 608 which has rotated in the opposite direction. The sheet is guided from the branch path 641 to the transport path 604 and discharged from the outlet roller pair 605 to the discharge module 700.

[0024] In this embodiment, the third switching section 607 is an example of a switching section and is positioned on the side facing the plurality of first ridge-shaped sections 610a, which will be described later, in a direction perpendicular to the virtual plane 610v (up and down direction). The third switching section 607 switches between a first position that allows the sheet to be transported in the second direction D2 relative to the first guide 610, and a second position that allows the sheet to be transported in the first direction D1 by the first guide 610. When the third switching section 607 is in the first position, the reversing roller 608 transports the sheet, which has been guided from above from the third switching section 607 to the first guide 610, in the second direction D2, and stops rotating after the upstream end of the sheet in the second direction D2 has passed the third switching section 607. When the third switching section 607 switches from the first position to the second position, the reversing roller 608 reverses its direction of rotation and transports the sheet in the first direction D1 to guide it to the first guide 610.

[0025] [Second Reversal Section] Next, the intermediate path 643 and the reversal path 642 in the second reversal section 640 will be described in detail using Figures 4(a) to 8. Figure 4(a) is a perspective view showing the intermediate path 643 and the reversal path 642. The intermediate path 643 is formed by an upper guide G1 that guides the sheet facing the upper surface of the sheet and a lower guide G2 that guides the sheet facing the lower surface of the sheet. Part of the upper guide G1 is formed by the third switching section 607. The lower guide G2 is formed by the first guide 610 and the third guide 611. Part of the reversal path 642 is formed by the second guide 609. The second guide 609, the first guide 610, and the third guide 611 are each composed of multiple rib-shaped components arranged in the sheet width direction W. These rib-shaped components are fixed to axes 612, 613, 614, 615, 616, and 617 along the sheet width direction W, and are positioned in the sheet conveying direction and vertically. The rib-shaped components are made of resin. Therefore, compared to the case where the conveying guide (lower guide G2) is made of sheet metal, the possibility of scratching the surface of the conveyed sheet is reduced.

[0026] The first guide 610 is positioned below the intermediate path 643 that transports the sheet in the first direction D1 and the second direction D2, and forms the intermediate path 643. The rib-shaped components forming the first guide 610 have a first ridge-shaped portion 610a at their upper end. The first ridge-shaped portions 610a are spaced apart from each other in the sheet width direction W, extend in a direction intersecting the sheet width direction W, and have a first contact portion 610a1 that contacts and guides the sheet being transported. That is, the first ridge-shaped portions 610a do not contact the sheet over their entire length, and may not contact the sheet in areas other than the first contact portion 610a1, such as the upstream and downstream ends in the sheet transport direction, which are inclined downwards. The first ridge-shaped portions 610a are formed by a plane having a narrow width in the sheet width direction W. Preferably, both ends of the first ridge-shaped portions 610a in the sheet width direction W are rounded into a circular arc shape in cross-section. In this embodiment, the first ridge-like portion 610a is formed by a flat surface, but it is not limited to this, and may be a curved surface that curves in the sheet width direction W, or a linear shape along the conveying direction (first direction D1 and second direction D2). Furthermore, if we consider a virtual surface 610v (see Figure 6(a)) formed by connecting a plurality of first ridge-like portions 610a, this virtual surface 610v becomes the guide surface of the first guide 610.

[0027] The second guide 609 is positioned upstream of the first guide 610 in the first direction D1. The rib-shaped components forming the second guide 609 have a second ridge-shaped portion 609a at their upper end. The second ridge-shaped portions 609a are spaced apart from each other in the sheet width direction W, extend in a direction intersecting the sheet width direction W, and have a second contact portion 609a1 that contacts and guides the conveyed sheet. The rib-shaped components of the first guide 610 and the rib-shaped components of the second guide 609 are positioned so that their ends in the sheet conveying direction overlap each other, with their ends interlocking in the sheet conveying direction. That is, in the first direction D1, the downstream ends of the multiple second ridge-shaped portions 609a are positioned interlocked with the upstream ends of the multiple first ridge-shaped portions 610a.

[0028] The third guide 611 is positioned downstream of the first guide 610 in the first direction D1. The rib-shaped component forming the third guide 611 has a third ridge-shaped portion 611a at its upper end. The third ridge-shaped portions 611a are spaced apart from each other in the sheet width direction W, extend in a direction intersecting the sheet width direction W, and have a third contact portion 611a1 that contacts and guides the conveyed sheet. The rib-shaped components of the first guide 610 and the rib-shaped components of the third guide 611 are positioned so that their ends in the sheet conveying direction overlap each other, with their ends interlocking in the sheet conveying direction. That is, in the first direction D1, the upstream ends of the multiple third ridge-shaped portions 611a are positioned interlocked with the downstream ends of the multiple first ridge-shaped portions 610a.

[0029] Furthermore, the reversing roller 608 is an example of a conveying roller and is positioned in the overlapping region of the upstream end of the multiple first ridge-shaped portions 610a and the downstream end of the multiple second ridge-shaped portions 609a in the first direction D1.

[0030] Figure 4(b) is a plan view showing the intermediate path 643 and the reversal path 642, illustrating the sheet transport direction through which the leading edge of the sheet S passes. In the second guide 609, the leading edge of the sheet is transported in the second direction D2. Therefore, the second guide 609 is positioned with the orientation of its rib-shaped components angled outward toward the downstream side in the transport direction relative to the second direction D2. That is, the multiple second ridge-like portions 609a are positioned such that their upstream ends in the first direction D1 are further away from the transport center C1 of the transport path in the sheet width direction W than their downstream ends. Similarly, in the third guide 611, the leading edge of the sheet is transported in the first direction D1. Therefore, the third guide 611 is positioned with the orientation of its rib-like components angled outward toward the downstream side in the transport direction relative to the first direction D1. That is, the multiple third ridge-like portions 611a are positioned such that their downstream ends in the first direction D1 are further away from the transport center C1 of the transport path in the sheet width direction W than their upstream ends.

[0031] Here, we consider the direction of the spread of the rib-shaped component of the first guide 610. Since the sheet conveying direction of the sheet S is reversed by the reversing roller 608, the sheet conveying direction of the leading edge of the sheet in the first guide 610 can be either the first direction D1 or the second direction D2. Specifically, the first guide 610 guides the leading edge of the sheet being conveyed in the second direction D2 in the reversing path 642. Furthermore, the first guide 610 guides the leading edge of the sheet being conveyed in the first direction D1 in the intermediate path 643 after the sheet conveying direction is switched by the reversing roller 608. For this reason, the first guide 610 cannot be positioned at an angle that spreads outward toward the downstream side of the sheet conveying direction, like the second guide 609 and the third guide 611.

[0032] For example, as shown in Figure 5(a), suppose the rib-shaped component of the first guide 610c is positioned at an angle that spreads outward toward the second direction D2. In this case, when the sheet S is transported in the first direction D1 after being inverted by the reversing roller 608, the leading edge of the sheet will bite into the first guide 610c, which may cause a load on the sheet and lead to a sheet jam. On the other hand, as shown in Figure 5(b), suppose the rib-shaped component of the first guide 610d is positioned at an angle that spreads outward toward the first direction D1. In this case, when the sheet S is transported in the second direction D2 before being inverted by the reversing roller 608, the leading edge of the sheet will bite into the first guide 610d, which may cause a load on the sheet and lead to a sheet jam. Therefore, as shown in Figure 4(c), it is desirable to position the rib-shaped component parallel to the sheet transport direction so that the leading edge of the sheet does not bite into the first guide 610b during transport in either direction.

[0033] However, if the rib-shaped components are arranged parallel to the sheet conveying direction, the side edges of the sheet in the sheet width direction W may rub against the sides of the rib-shaped components during sheet conveying. If the side edges of the sheet continue to rub against the sides of the rib-shaped components during conveying, it may damage the sheet or cause a load on the sheet, potentially leading to a sheet jam. Therefore, in this embodiment, as shown in Figures 6(a) to 8, an inclined portion 618 is provided between the rib-shaped components of the first guide 610.

[0034] [First Guide] Next, the first guide 610 will be explained using Figures 6(a) to 8. Figure 6(a) is a view of the first guide 610 from the downstream side in the first direction D1. The first guide 610 is composed of multiple rib-shaped parts in the sheet width direction W, and the virtual surface 610v formed by connecting the first ridge-shaped parts 610a of the multiple rib-shaped parts serves as the guide surface. Figure 6(b) is a view of the first guide 610b from the sheet transport direction in the comparative example shown in Figure 4(c). Compared to the first guide 610 shown in Figure 6(a), in the first guide 610b shown in Figure 6(b), there is a possibility that the side edge of the sheet may fall between the rib-shaped parts. If the sheet is transported in a fallen state, the sheet may rub against the side of the guide, damaging the sheet, or a load may be applied to the sheet, potentially causing a sheet jam.

[0035] In contrast, in this embodiment, as shown in Figure 6(a), an inclined portion 618 is provided between at least some of the rib-shaped components among the plurality of rib-shaped components and adjacent rib-shaped components in the sheet width direction W. The inclined portion 618 is an example of a first inclined portion and has an inclined surface that is inclined to move away from the virtual surface 610v toward the transport center C1. In other words, the inclined surface is inclined so that as it moves away from the transport center C1 in the sheet width direction, it approaches the guide (third switching portion 607) positioned opposite the first guide 610. As a result, because there is an inclined portion 618 between the rib-shaped components, the sheet does not fall between the rib-shaped components, enabling stable sheet transport. Furthermore, since the inclined portion 618 is inclined in the sheet width direction W, even if the sheet shifts laterally during sheet transport, the side edges of the sheet can be prevented from rubbing against the sides of the rib-shaped components. This prevents sheet damage and sheet jams.

[0036] In this embodiment, one rib-shaped component and an inclined portion 618 adjacent to the conveying center C1 side (conveying center side) are integrally formed. Multiple rib-shaped components, each with an integrally formed inclined portion 618, are arranged in the sheet width direction W and fixed using shafts 614 and 615 to form the first guide 610. However, this is not limited to this, and the entire first guide 610 may be integrally formed, or all the rib-shaped components and the inclined portion 618 may be constructed as separate parts.

[0037] In this embodiment, some of the multiple inclined sections 618 are positioned on one side of the conveying center C1 in the sheet width direction W (for example, in the forward direction F). Other parts of the multiple inclined sections 618 are positioned on the other side of the conveying center C1 in the sheet width direction W (for example, in the rear direction B). The inclined sections 618 positioned on one side of the conveying center C1 and the inclined sections 618 positioned on the other side of the conveying center C1 have opposite inclination directions in the sheet width direction W.

[0038] Furthermore, in this embodiment, the inclined portion 618 is shorter than the first ridge-like portion 610a in the first direction D1 (Figure 8). Moreover, the inclined portion 618 is positioned to overlap with the center of the first ridge-like portion 610a in the first direction D1. The inclined surface of the inclined portion 618 is inclined at an angle of about 30 degrees with respect to the virtual surface 610v (Figure 6(a)). However, it is not limited to about 30 degrees, and it is preferable that it is inclined at an angle of at least 45 degrees or less.

[0039] In this embodiment, as shown in Figure 4(b), the reversing roller 608 has a first roller 608a and a second roller 608b. The first roller 608a and the second roller 608b are rollers that contact the sheet and convey it by rotation, and are arranged coaxially with respect to the conveying center C1 in the sheet width direction W. The inclined portion 618 is located in a region that does not overlap with the region Ar1 between the side surface of the first roller 608a on the conveying center C1 side and the side surface of the second roller 608b on the conveying center C1 side in the sheet width direction W. Sheets narrower than this region Ar1 are not conveyed. Therefore, the inclined portion 618 is not located in a part that overlaps with the paper-passing area of ​​the smallest size sheet that can be conveyed. This makes it possible to avoid providing an unnecessary inclined portion 618 in the region Ar1 through which the sheet does not pass in the reversing module 600. Furthermore, it is preferable not to place the inclined portion 618 in a part that does not overlap with the paper-passing area of ​​the largest size sheet that can be conveyed.

[0040] Figure 7 is a side view of the first guide 610 as seen from the sheet width direction W. A conveying surface 619 is formed at the upstream end of the first guide 610 in the first direction D1. The conveying surface 619 is an example of a second inclined section, and in the first direction D1, it is an inclined surface that slopes away from the virtual surface 610v from the upstream end of the inclined section 618 toward the upstream. By providing the conveying surface 619, it is possible to prevent the leading edge of the sheet being conveyed from the second guide 609 in the first direction D1 from getting caught on the upstream end of the inclined section 618. On the other hand, a conveying surface 620 is formed at the downstream end of the second guide 609 in the first direction D1. The conveying surface 620 is an inclined surface that slopes away from the virtual surface 610v on the downstream end side in the first direction D1. By providing the conveying surface 620, it is possible to prevent the leading edge of the sheet being conveyed from the first guide 610 in the second direction D2 from getting caught on the upstream end of the second guide 609.

[0041] Figure 8 is a plan view of the first guide 610. As shown in Figure 8, at the upstream end of the first guide 610 in the first direction D1, the second guide 609 and the rib-shaped component are arranged to alternately enter the sheet width direction W. At the downstream end of the first guide 610 in the first direction D1, the third guide 611 and the rib-shaped component are arranged to alternately enter the sheet width direction W.

[0042] Furthermore, the first guide 610 has a conveying surface 621 that protrudes upstream in the first direction D1 from the conveying surface 619, and a conveying surface 622 that protrudes downstream in the first direction D1 from the inclined portion 618. By providing these conveying surfaces 621 and 622, the gap between adjacent rib-shaped parts can be narrowed, enabling stable sheet conveyance between rib-shaped parts.

[0043] As described above, according to this embodiment, the first guide 610 has an inclined portion 618 between the rib-shaped parts. Therefore, the sheet is prevented from falling between the rib-shaped parts, enabling stable sheet transport. Furthermore, since the inclined portion 618 is inclined in the sheet width direction W, even if the sheet shifts laterally during sheet transport, the side edges of the sheet will not rub against the sides of the rib-shaped parts. This suppresses sheet damage and sheet jams.

[0044] Furthermore, according to this embodiment, the first guide 610 is configured so that the sheet conveying direction can be switched between two directions: a first direction D1 and a second direction D2. For this reason, the rib-shaped components need to be arranged parallel to the sheet conveying direction, but since the inclined portion 618 is provided, sheet damage and sheet jamming can be suppressed. As a result, sheet damage and sheet jamming can be suppressed even when the sheet conveying direction is switched between two directions.

[0045] Furthermore, according to this embodiment, a conveying surface 619 is formed at the upstream end of the first guide 610 in the first direction D1. Therefore, it is possible to prevent the leading edge of the sheet being conveyed from the second guide 609 in the first direction D1 from getting caught on the upstream end of the inclined portion 618.

[0046] In the embodiments described above, the first guide 610 was described in a case where the sheet conveying direction can be switched between two directions, a first direction D1 and a second direction D2, but it is not limited to this. For example, even in a guide where the sheet conveying direction is only one direction, an inclined portion 618 may be provided between the rib-shaped components. In this case, the rib-shaped components may be arranged parallel to the sheet conveying direction, or they may be arranged so that the downstream side in the sheet conveying direction is wider.

[0047] Furthermore, although the above-described embodiment described a case where the first guide 610 is a guide positioned below the transport path, it is not limited to this. For example, it may be positioned on both sides (upper and lower) of the transport path. Alternatively, it may be positioned only on the upper side of the transport path. In other words, although the above-described embodiment describes a case where the first guide 610 of the lower guide G2 has an inclined portion 618 and the upper guide G1 does not have an inclined portion 618, it is not limited to this. Both the upper guide G1 and the lower guide G2 may be provided with an inclined portion 618. Alternatively, the inclined portion 618 may be provided only on the upper guide G1 and not on the lower guide G2. Also, although this embodiment described a case where the upper guide G1 and the lower guide G2 form a transport path as a pair of transport guides facing each other in the vertical direction, it is not limited to this. That is, the pair of transport guides may face each other in the horizontal direction (including the direction inclined with respect to the horizontal direction), and the transport path may face in the vertical direction (including the direction inclined with respect to the vertical direction). In this case as well, it is conceivable that one or both of the pair of transport guides have an inclined portion 618.

[0048] Furthermore, although the above-described embodiment described the case where the sheet transport device is applied to the reversal module 600 as an example, it is not limited to this. For example, it may be applied to the first reversal unit 420 of the fixing module 400, or to other modules, including cases where the transport direction is unidirectional. Moreover, the sheet transport device can be applied to inspection devices that read and inspect the image of the sheet after image formation, or to automatic document feeders that feed originals for image reading.

[0049] Furthermore, although the above-described embodiment described the case in which the image forming system is applied to an inkjet recording system 1 of the inkjet recording method, it is not limited to this and may also be applied to an electrophotographic image forming apparatus. [Explanation of symbols]

[0050] 1…Inkjet recording system (image forming system), 600…Reversal module (sheet transport device), 607…Third switching section (switching section), 608…Reversal roller (transport roller), 608a…First roller, 608b…Second roller, 609…Second guide, 609a…Second ridge section, 609a1…Second contact section, 610…First guide, 610a…First ridge section, 610a1…First contact section, 610v…Virtual surface, 611…Third guide, 611a…Third ridge section, 611a1…Third contact section, 618…Inclined section (first inclined section), 619…Transport surface (second inclined section), 643…Intermediate path (transport path), D1…First direction, S…Sheet, W…Sheet width direction (width direction)

Claims

1. In a sheet transport device that transports sheets, It includes a first guide that forms a transport path for transporting the sheet in a first direction, The first guide is, A plurality of first ridge-like portions are arranged at intervals from each other in the width direction perpendicular to the first direction, extend in a direction intersecting the width direction, and have first contact portions that contact and guide the sheet being conveyed, The device has a plurality of first inclined portions, each of which is positioned between at least some of the plurality of first ridge-shaped portions and adjacent first ridge-shaped portions in the width direction, and which are inclined to move away from the virtual plane formed by connecting the plurality of first ridge-shaped portions toward the transport center of the transport path, A sheet conveying device characterized by the following features.

2. A portion of the plurality of first inclined portions is arranged on one side from the transport center in the width direction, The other of the multiple first inclined portions are arranged on the other side of the conveying center in the width direction. The first inclined portion located on one side of the conveying center and the first inclined portion located on the other side of the conveying center have opposite inclination directions in the width direction. The sheet conveying device according to feature 1.

3. It contacts the sheet and conveys it by rotation, and comprises a first roller and a second roller arranged on either side of the conveying center in the width direction, The first inclined portion is positioned in a region in the width direction that does not overlap with the region between the side surface of the first roller on the conveying center side and the side surface of the second roller on the conveying center side. The sheet conveying device according to feature 1.

4. The first inclined portion is shorter than the first ridge-like portion in the first direction. The sheet conveying device according to feature 1.

5. The first inclined portion is positioned in the first direction such that it coincides with the center of the first ridge-like portion. The sheet conveying device according to feature 4.

6. The first inclined portion is inclined at an angle of 45 degrees or less with respect to the virtual plane. The sheet conveying device according to feature 1.

7. The first ridge-like portion is arranged parallel to the first direction, The sheet conveying device according to feature 1.

8. The first guide guides the sheet being transported in a second direction opposite to the first direction. The sheet conveying device according to feature 1.

9. In the first direction, a second guide is provided, which is positioned upstream of the first guide. The second guide has a plurality of second ridge-like portions that are spaced apart from each other in the width direction, extend in a direction intersecting the width direction, and have second contact portions that contact and guide the sheet being conveyed. In the first direction, the downstream ends of the plurality of second ridge-like portions are positioned so as to be intertwined with each other relative to the upstream ends of the plurality of first ridge-like portions. The sheet conveying device according to feature 1.

10. The first guide has a second inclined portion that, in the first direction, is inclined upstream from the upstream end of the first inclined portion so as to move away from the virtual plane. The sheet conveying device according to feature 9.

11. The plurality of the second ridge-like portions are arranged such that their upstream ends in the first direction are further away from the transport center in the width direction than their downstream ends. The sheet conveying device according to feature 10.

12. In the first direction, the overlapping region of the upstream ends of the plurality of first ridge-shaped portions and the downstream ends of the plurality of second ridge-shaped portions is provided with a conveying roller that contacts and conveys the sheet. The conveying roller switches the sheet conveying direction between the first direction and a second direction opposite to the first direction by reversing its rotation direction. The sheet conveying device according to feature 10.

13. The device includes a switching unit that is positioned on the side opposite to a plurality of first ridge-like portions in a direction perpendicular to the virtual surface, and switches between a first position that allows the sheet to be transported in the second direction relative to the first guide, and a second position that allows the sheet to be transported in the first direction relative to the first guide. When the switching section is in the first position, the conveying roller conveys the sheet guided by the first guide from the switching section in the second direction, and stops rotating after the upstream end of the sheet in the second direction has passed the switching section. When the switching unit switches from the first position to the second position, the conveying roller reverses its rotational direction and conveys the sheet in the first direction to guide it to the first guide. The sheet conveying device according to feature 12.

14. In the first direction, a third guide is provided, which is located downstream of the first guide. The third guide has a plurality of third ridge-like portions that are spaced apart from each other in the width direction, extend in a direction intersecting the width direction, and have third contact portions that contact and guide the sheet being conveyed. In the first direction, the upstream ends of the plurality of third ridge-like portions are positioned so as to be intertwined with each other relative to the downstream ends of the plurality of first ridge-like portions. The sheet conveying device according to feature 1.

15. The plurality of the third ridge-like portions are arranged such that their downstream ends in the first direction are further away from the transport center in the width direction than their upstream ends. The sheet conveying device according to feature 14.

16. The first direction is the horizontal direction, The first guide is located below the transport path. The sheet conveying device according to feature 1.

17. An image forming apparatus that forms an image on a sheet, A sheet transport device comprising: An image forming system characterized by the following features.

Images