Sheet transport device and image forming apparatus

Abstract

To reduce noise during the switching of the switching component. [Solution] The sheet conveying device comprises a switching member (3001) that can be switched between a first position and a second position, a plurality of cushioning members (600) that contact and cushion when the switching member is switched to the second position, and a plurality of high sliding members (5001) that can be attached to the switching member and have higher sliding properties with respect to the sheet than the switching member. The switching member is supported by a support and has a plurality of ribs (303) arranged in the width direction. Each of the plurality of cushioning members is arranged so that it can contact the outer edge of any of the plurality of ribs when the switching member is in the second position. The high sliding members are attached to the target ribs (303A) and are arranged so that the sliding portion is located outside the outer edge of the target rib. The high sliding members are positioned in the width direction offset from the cushioning members.

Description

Technical Field

[0001] The present invention relates to a sheet conveying device for conveying sheets and an image forming apparatus.

Background Art

[0002] For example, some image forming apparatuses such as copiers and printers have a switching guide (so-called flapper) for switching the conveyance destination of sheets (see Patent Document 1). In this switching guide, weight reduction is required to achieve a high-speed switching operation. Therefore, the switching guide is configured to form a plurality of guide ribs supported by a support portion extending in the sheet width direction, and guide the sheet at the outer edges of the plurality of guide ribs. However, when guiding the sheet with a plurality of guide ribs, there is a risk that defects or streaks may be formed on the sheet. Therefore, it is also conceivable to attach a guide member with high slidability to the plurality of guide ribs, but there is a problem that attaching the guide member to all the guide ribs hinders weight reduction. Therefore, in Patent Document 1, it is proposed to attach the guide member only to the selected guide ribs among the plurality of guide ribs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the above-described switching guide is driven and switched by, for example, a solenoid or the like, there is a risk of generating noise by colliding with a fixed member such as a conveyance guide.

[0005] Therefore, an object of the present invention is to provide a sheet conveying device and an image forming apparatus capable of reducing noise during switching of a switching member. [Means for solving the problem]

[0006] One aspect of the present invention comprises: a conveying unit for conveying a sheet; a first conveying path for guiding the sheet conveyed by the conveying unit; a second conveying path branching off from the first conveying path at a branching section and guiding the sheet conveyed by the conveying unit; a switching member that can switch between a first position for guiding the conveyed sheet to the first conveying path downstream of the branching section in the conveying direction, and a second position for guiding the conveyed sheet to the second conveying path; a plurality of cushioning members that contact and cushion the switching member when the switching member is switched to the second position; and a plurality of high-sliding members that can be attached to the switching member and have higher sliding properties with respect to the sheet than the switching member, wherein the switching member comprises: a support portion arranged such that the width direction perpendicular to the conveying direction is the longitudinal direction; and a support portion A sheet conveying device comprising a plurality of ribs held and arranged in line in the width direction, wherein the switching member forms a first guide portion capable of guiding a sheet to the first conveying path when in the first position and a second guide portion capable of guiding a sheet to the second conveying path when in the second position, at least by the outer edges of the plurality of ribs, and each of the plurality of high sliding members has a sliding portion that can slide on the sheet, is attached to a target rib among the plurality of ribs, and is arranged such that the sliding portion is located outside the outer edge of the target rib, thereby forming a third guide portion capable of guiding a sheet to the first conveying path when in the first position, and is positioned offset from the buffer member in the width direction.

[0007] One aspect of the present invention is a sheet conveying device comprising: a conveying unit for conveying a sheet; a first conveying path for guiding the sheet conveyed by the conveying unit; a second conveying path branching off from the first conveying path at a branching section and guiding the sheet conveyed by the conveying unit; a switching member having a plurality of ribs that can be switched between a first position that guides the conveyed sheet to the first conveying path downstream of the branching section in the conveying direction, and a second position that guides the conveyed sheet to the second conveying path; a sponge that contacts the switching member when the switching member is switched to the second position; and a mounting member that can be attached to the switching member, wherein when the switching member is in the first position, the sheet is guided to the first conveying path by the ribs of the switching member and the mounting member attached to the switching member, and the sponge is arranged not to contact the mounting member but to contact at least one of the plurality of ribs. [Effects of the Invention]

[0008] According to the present invention, noise during the switching of the switching member can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing a printer according to the first embodiment. [Figure 2] (a) is a cross-sectional view showing the flapper and its vicinity in the first position. (b) is a cross-sectional view showing the flapper and its vicinity in the second position. [Figure 3] This is a perspective view showing the first and second guides with the flapper removed. [Figure 4] (a) is a side view showing the branch section with a flapper and its vicinity. (b) is a side view showing the branch section and its vicinity with the flapper removed. [Figure 5] This is a perspective view showing the side of the first guide section of the flapper with the add-on guide rib attached. [Figure 6] This is a perspective view showing the side of the second guide section of the flapper with the add-on guide rib attached. [Figure 7] This is a cross-sectional view showing the positional relationship between the add-on guide rib according to the first embodiment, the target rib to which it is attached, and the roller. [Figure 8] This is a cross-sectional view showing the drive mechanism of the flapper. [Figure 9] This is a cross-sectional view showing the positional relationship between the add-on guide rib according to the second embodiment, the target rib to which it is attached, and the roller. [Figure 10] This is a cross-sectional view showing the positional relationship between the add-on guide rib according to the third embodiment, the target rib to which it is attached, and the roller. [Figure 11] This is a cross-sectional view showing the positional relationship between the add-on guide rib according to the fourth embodiment, the target rib to which it is attached, and the roller. [Figure 12] This is a cross-sectional view showing the positional relationship between the add-on guide rib according to the fifth embodiment, the target rib to which it is attached, and the roller. [Modes for carrying out the invention]

[0010] <First Embodiment> The first embodiment will be described in detail below with reference to the drawings. In this specification, subscripts used in reference numerals are used to distinguish between different types of similar components (parts). When there is no particular need for distinction, the reference numerals without subscripts will be used in the description.

[0011] [Printer configuration] First, a printer 100, which is an example of an image forming apparatus according to the first embodiment, will be described using Figure 1. Figure 1 is a schematic diagram showing the printer according to the first embodiment. In Figure 1, the X direction is the horizontal direction, which is the left-right direction of the printer 100. The Y direction is also the horizontal direction, which is the front-to-back direction of the printer 100, and is also the width direction perpendicular to the sheet transport direction. The Z direction is the up-and-down direction.

[0012] As shown in Figure 1, the printer 100 is a so-called laser beam printer and has a printer body 101, which is the main body of the device. Inside the printer body 1, there is an image forming unit 102 that forms an image on a sheet and a sheet transport unit 104 that transports the sheet. The printer 100 also has an image reading device 103 installed above the printer body 101. A discharge space P for sheet ejection is formed between the image reading device 103 and the printer body 101. The printer body 101 also has a sheet feeding unit 110 that feeds sheets S from a paper feed cassette 111 to the image forming unit 102 and a sheet transport unit 104 that transports sheets from the image forming unit 102 to the outside of the printer 100. The printer body 101 also has a reversal transport unit 20, etc., for transporting the sheet with the image formed on the first surface back to the image forming unit 102. The sheet transport section 104 includes, in more detail, a fuser 150, a pair of post-fusing rollers 160, a first discharge roller pair 210, an upstream transport roller pair 180, a downstream transport roller pair 190, a second discharge roller pair 220, etc., which will be described in more detail later.

[0013] The image forming unit 102 includes a scanner unit 142, four process cartridges 140 for forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (Bk), four photoreceptor drums 141, four developer units 143, and the like. The image forming unit 102 also includes an intermediate transfer unit 145 positioned above the process cartridges 140. The operation of these components will be described in detail in the image forming operation section below.

[0014] The intermediate transfer unit 145 includes an intermediate transfer belt 146 wound around a secondary transfer inner roller 131 or the like. The intermediate transfer unit 145 also includes a primary transfer roller 144 provided inside the intermediate transfer belt 146 and contacting the intermediate transfer belt 146 at a position facing the photoreceptor drum 141. Here, the intermediate transfer belt 146 is arranged to contact each photoreceptor drum 141 and is driven by a driving unit (not shown) to rotate in the direction of arrow A. Then, by applying a positive transfer bias to the intermediate transfer belt 146 by the primary transfer roller 144, the negatively charged toner images of each color on the photoreceptor drum 141 are sequentially multi-transferred to the intermediate transfer belt 146. Thereby, a full-color image is formed on the intermediate transfer belt.

[0015] Note that at a position facing the secondary transfer inner roller 131 of the intermediate transfer unit 145, a secondary transfer roller 132 that constitutes a secondary transfer unit 130 for transferring the full-color image formed on the intermediate transfer belt to the sheet S is provided. Further, a fixing unit 150 is arranged above the secondary transfer roller 132, and a discharge unit 200 as a sheet discharge device is arranged on the downstream side of the fixing unit 150 in the sheet conveyance direction. The discharge unit 200 is provided with a first discharge roller pair 210 and a second discharge roller pair 220.

[0016] Note that the printer 100 includes a feed passage R for conveying the sheet fed from the sheet feeding unit 110 to the image forming unit 102, and a first conveyance path R1 for conveying the sheet on which an image is formed by the image forming unit 102 to the first discharge roller pair 210. The printer 100 also includes a second conveyance path R2 that branches at a branch portion JN from the first conveyance path R1 and conveys the sheet to the second discharge roller pair 220. Furthermore, the printer 100 includes a re-conveyance path R3 provided in the reverse conveyance unit 20 that connects from the second conveyance path R2 back to the first conveyance path R1 to re-convey the sheet. In the following description, the portion from the image forming unit 102 to the branch portion JN in the first conveyance path R1 is also referred to as the first upstream conveyance path R1a, and the portion from the branch portion JN to the first discharge roller pair 210 in the first conveyance path R1 is also referred to as the first downstream conveyance path R1b.

[0017] Furthermore, a pair of post-fixing rollers 160 is arranged in the first upstream transport path R1a to pull out and transport the sheet discharged from the fixer 150. This pair of post-fixing rollers 160 has a post-fixing inner roller 161 and a post-fixing outer roller 162 which acts as an upstream roller that abuts against it to form a nip.

[0018] Furthermore, the second transport path R2 is equipped with an upstream transport roller pair 180 and a downstream transport roller pair 190 that transport the sheets that are transported after branching off from the first transport path R1 at the branching section JN. The upstream transport roller pair 180 has an upstream transport inner roller 181 and an upstream transport outer roller 182 that contacts it to form a nip. Similarly, the downstream transport roller pair 190 has a downstream transport inner roller 191 and a downstream transport outer roller 192 that contacts it to form a nip.

[0019] Furthermore, a flapper 3001, which will be described in more detail later, is positioned at the branching section JN that separates the first transport path R1 and the second transport path R2. This flapper 3001 can be switched between a first position P1 (see Figure 2(a)) and a second position P2 (see Figure 2(b)). When the flapper 3001 is in the first position P1, it guides the transported sheet from the first upstream transport path R1a to the first downstream transport path R1b (i.e., to the first transport path R1). When the flapper 3001 is in the second position P2, it guides the transported sheet from the first upstream transport path R1a to the second transport path R2. In addition, a roller 230, which acts as a rotating body, is positioned opposite the flapper 3001 in the first transport path R1. The roller 230 is configured to rotate in accordance with the transported sheet.

[0020] Furthermore, the second transport path R2 is equipped with a flapper 400 that can be switched between a position that guides the transported sheet to the second discharge roller pair 220 and a position that guides the sheet, which has been inverted by the second discharge roller pair 220 as described later, to the re-transport passage R3.

[0021] [Image Formation Process] Next, the image formation operation of the printer 100 configured in this way will be described. When the image formation operation starts, first, a laser beam is emitted from the scanner unit 142 based on image information from a personal computer or the like (not shown). This laser beam sequentially exposes the surface of the photoreceptor drum 141, whose surface is uniformly charged to a predetermined polarity and potential, to form an electrostatic latent image on the photoreceptor drum. After this, this electrostatic latent image is developed and made visible with toner. Then, the toner images of the four colors, yellow (Y), magenta (M), cyan (C), and black (Bk), on the photoreceptor drum are transferred to the intermediate transfer belt 146 by a transfer bias applied to the primary transfer roller 144, forming a full-color toner image on the intermediate transfer belt. The toner remaining on the photoreceptor drum is collected in an unshown toner discharge container by a cleaning unit (not shown) provided in the process cartridge 140.

[0022] In parallel with this toner image formation operation, the sheet S contained in the paper feed cassette 111 is fed out by the sheet feeding unit 110. After this, the sheet S is transported by the transport roller pair 121 to the registration roller pair 120, which acts as a skew correction unit, and the skew is corrected by the registration roller pair 120. Next, the transport roller pair 122 provided on the registration roller pair 120 rotates to align the leading edge of the skew-corrected sheet S with the full-color toner image on the intermediate transfer belt, and the sheet S is transported to the secondary transfer unit 130. Then, in the secondary transfer unit 130, the full-color toner image is transferred onto the sheet S all at once by the secondary transfer bias applied to the secondary transfer roller 132.

[0023] Next, the sheet S onto which the full-color toner image has been transferred is transported to the fuser 150, where heat and pressure are applied to melt and mix the toners of each color, fixing the toner image on the sheet S as a full-color image. After this, the sheet S with the fixed toner image is discharged, for example, by the first discharge roller pair 210 provided on the first transport path R1 to the discharge tray 170, which serves as a loading section at the bottom of the discharge space P. Alternatively, if, for example, the discharge tray 171, which serves as a loading section, is selected as the discharge destination, the flapper 3001 is moved from the first position P1, shown by a solid line, which directs the sheet toward the first discharge roller pair 210, to the second position P2, shown by a dashed line, which guides the sheet toward the inversion transport section 20. As a result, the sheet is guided toward the second transport path R2 and discharged by the second discharge roller pair 220 to the discharge tray 171 provided in the discharge space P.

[0024] Furthermore, when forming images on both sides of the sheet, the flapper 3001 is moved from the first position P1 to the second position P2. As a result, the sheet with the image formed on the first surface reaches the second discharge roller pair 220, which is also a reversible inversion conveying section 20 located in the second conveying path R2. After this, the flapper 400 is moved from the position indicated by the solid line, which directs the sheet toward the second discharge roller pair 220, to the position indicated by the dashed line, which directs the sheet toward the re-conveying passage R3 of the inversion conveying section 20. Then, due to the reversal of the second discharge roller pair 220, the sheet is conveyed to the re-conveying passage R3 in an inverted state. After this, the sheet is re-conveyed to the secondary transfer section 130 via the re-conveying passage R3, where an image is formed on the second surface opposite to the first surface.

[0025] Then, after the toner image is fixed again by the fuser 150, the sheet S with images formed on both sides is discharged onto the discharge tray 170 by the first discharge roller pair 210. Alternatively, the sheet S with images formed on both sides is discharged onto the discharge tray 171 provided in the discharge space P by the second discharge roller pair 220 by moving the flapper 3001 to the second position P2.

[0026] [Configuration of the branching section and its vicinity] Next, the configuration of the branch section JN and its vicinity will be explained using Figures 2 to 4. Figure 2(a) is a cross-sectional view showing the flapper in the first position and its vicinity. Figure 2(b) is a cross-sectional view showing the flapper in the second position and its vicinity. Figure 3 is a perspective view showing the first guide and second guide with the flapper removed. Figure 4(a) is a side view showing the branch section with the flapper and its vicinity. Figure 4(b) is a side view showing the branch section and its vicinity with the flapper removed.

[0027] As described above, downstream of the fuser 150 in the transport direction, there is a first transport path R1 and a second transport path R2 that branches off from the first transport path R1 at a branching section JN. As shown in Figures 2(a) and 2(b), a flapper 3001 is provided at this branching section JN that can switch between a first position P1 that guides the sheet to the first transport path R1 and a second position P2 that guides the sheet to the second transport path R2. The first upstream transport path R1a of the first transport path R1 is formed between a first guide G1 and a third guide G3, which are guide members, and the first downstream transport path R1b is formed between the first guide G1 and the second guide G2. The second transport path R2 is formed between the second guide G2 and the third guide G3.

[0028] Upstream of the branching section JN in the conveying direction, a pair of post-fixing rollers 160 is positioned adjacent to the flapper 3001 in the first upstream conveying path R1a. The post-fixing inner roller 161 of this post-fixing roller pair 160 is positioned embedded in the guide surface of the first guide G1 (see Figure 3), and the post-fixing outer roller 162 is positioned embedded in the guide surface of the third guide G3. As shown in Figure 3, the post-fixing inner roller 161 is a so-called single-piece roller, where the roller portion that contacts the sheet is made of silicone, rubber, etc., supported by a support shaft, and is driven by a motor (not shown). On the other hand, the post-fixing outer roller 162 has a support shaft 162b and a plurality of roller portions 162a that act as contact rotating parts that contact the sheet, as shown by the dotted line in Figure 4(a). Multiple roller sections 162a are supported by a support shaft 162b and are spaced apart so as to be divided in the width direction; in other words, the post-fixed outer roller 162 is composed of so-called ball-shaped rollers. The roller sections 162a of this post-fixed outer roller 162 are positioned to overlap with the target rib 303A and the add-on guide rib 5001, which will be described in more detail later, in the width direction when viewed from the conveying direction. The post-fixed outer roller 162 is a driven roller that moves with the post-fixed inner roller 161.

[0029] Furthermore, downstream of the branching section JN, the second transport path R2 has an upstream transport roller pair 180 and a downstream transport roller pair 190, as shown in Figures 1 and 3. Of these, the upstream transport inner roller 181 of the upstream transport roller pair 180 and the downstream transport inner roller 191 of the downstream transport roller pair 190 are positioned embedded in the guide surface of the second guide G2, as shown in Figure 3. Although not shown in Figure 3, the upstream transport outer roller 182 of the upstream transport roller pair 180 and the downstream transport outer roller 192 of the downstream transport roller pair 190 are positioned embedded in the guide surface of the third guide G3.

[0030] Next, the part of the first guide G1 that forms the guide surface will be explained using Figures 3 and 4. As shown in Figures 3 and 4(b), the first guide G1 has guide sections G1A, G1B, and G1C in order from upstream in the conveying direction, which form the guide surface. The fixed internal roller 161 is positioned between guide section G1A and guide section G1B in the conveying direction. Guide section G1A is positioned opposite the third guide G3 (see Figure 2), and together with the third guide G3, it forms the first upstream conveying path R1a. Guide sections G1B and G1C are positioned opposite the flapper 3001, as shown in Figures 2(a) and 4(a), and together with the flapper 3001 at the first position P1, they form the first conveying path R1 at the branching section JN. In other words, the flapper 3001 at the first position P1 forms a part of the first conveying path R1.

[0031] As shown in Figures 3 and 4(b), the guide section G1B has multiple ribs G1BR arranged in the width direction as second ribs. In this embodiment, cushioning members 600 made of sponge are placed in three locations on the guide section G1B so as to fit between these ribs G1BR. These ribs G1BR are positioned so as to partially overlap with the ribs 303 of the flapper 3001 at the second position P2 when viewed from the width direction. Details regarding the position of the cushioning members 600 will be described later. Furthermore, the guide section G1B forms a fourth guide section on the outer edges of the multiple ribs G1BR that can guide the sheet into the first transport path R1. The portion of this fourth guide section formed by the outer edges of the multiple ribs G1BR can be said to be a virtual surface connecting the outer edges of those ribs G1BR in the transport direction and width direction. Here, sponge is used as an example for the cushioning member 600. However, the cushioning member 600 may be made of an elastic material such as rubber, or it may be made of cloth.

[0032] Furthermore, the guide section G1C has a fifth guide section that can guide the sheet along the first transport path R1. Multiple (two) openings G1Ca are formed in this guide section G1C, and the rollers 230 are positioned in these openings G1Ca. The rollers 230 are rotatably supported by the first guide G1 by a rotating shaft (not shown in the figure) and rotate freely in contact with the sheet. As a result, as shown by the dashed line in Figure 2(a), the sheet being transported by being pulled by the first discharge roller pair 210 comes into contact with the rollers 230, which reduces the transport resistance compared to contacting the first guide G1.

[0033] [Flappa's composition] Next, the detailed configuration of the flapper 3001 according to the first embodiment will be described using Figures 5 to 7. Figure 5 is a perspective view showing the side of the first guide portion of the flapper with the add-on guide rib attached. Figure 6 is a perspective view showing the side of the second guide portion of the flapper with the add-on guide rib attached. Figure 7 is a cross-sectional view showing the positional relationship between the add-on guide rib according to the first embodiment, the target rib to which it is attached, and the roller. Note that Figure 7 shows the flapper 3001 with the add-on guide rib 5001 attached, but details of the add-on guide rib 5001 will be described later, and here we will describe the configuration of the flapper 3001.

[0034] As shown in Figures 5, 6, and 7, the flapper 3001 as a switching member according to the first embodiment is broadly composed of a support shaft 301, a support portion 302, and a plurality of ribs 303 (22 in this embodiment) as first ribs. The flapper 3001 is also composed of a plurality of ribs 304 (14 in this embodiment) that are smaller than the ribs 303 and are provided auxiliaryly between the ribs 303 in the Y direction, which is the width direction, on the side of the first guide portion 300A, which will be described in more detail later.

[0035] The support shaft 301 is positioned to penetrate the support portion 302 so as to protrude from it in the width direction (Y direction), and is fixed to the support portion 302 while being rotatably supported with respect to the second guide G2. That is, the entire flapper 3001 is configured to rotate around the support shaft 301, and can be switched between a first position P1 and a second position P2 by the drive mechanism 900 described later (see Figure 2).

[0036] The support portion 302 is positioned so as to extend along the Y direction, which is the axial direction and width direction of the support shaft 301. As shown in Figure 7, the support portion 302 is formed in a roughly triangular shape, which is generally slightly smaller than the rib 303 when viewed from the axial direction. The support portion 302 is also configured to allow the attachment of an add-on guide rib 5001, which will be described in more detail later, as a mounting member.

[0037] Each of the multiple ribs 303 is arranged in the width direction (Y direction), as shown in Figures 5 and 6, and is formed as a rib shape protruding from the support portion 302. Each rib 303, as shown in Figure 7, is formed in a roughly triangular shape that is generally slightly larger than the support portion 302 when viewed from the width direction, and the acute-angled vertex of the triangle is formed to face upstream in the conveying direction. Of the multiple ribs 303, the target rib 303A, which will be adjacent to the add-on guide rib described in more detail later, has the same shape as the other ribs 303 and refers to the rib 303 that is positioned in the width direction at a selected location, as described later. The width direction position of the target rib 303A will be described later.

[0038] Furthermore, as shown in Figure 5, each of the multiple ribs 304 is formed in a rib shape that protrudes from the support portion 302, so as not to protrude upstream in the conveying direction from the support portion 302, and to be at the same height as the adjacent rib 303.

[0039] As shown in Figure 7, the flapper 3001 has a first guide portion 300A (see Figure 5) that forms part of the first transport path R1 when it is in the first position P1 (see Figure 2(a)). The flapper 3001 also has a second guide portion 300B (see Figure 6) that forms part of the second transport path R2 when it is in the second position P2 (see Figure 2(b)). The first guide portion 300A has an upstream portion 300Aa that is upstream in the transport direction and a downstream portion 300Ab that is located downstream of the upstream portion Aa in the transport direction. In this embodiment, the upstream portion 300Aa is formed by a first outer edge portion 303a in ribs 303 where the add-on guide rib 5001 described later is not attached adjacent to it. Similarly, the downstream portion 300Ab is formed by a first outer edge portion 303a in ribs 303 where the add-on guide rib 5001 described later is not attached adjacent to it. Furthermore, the upstream portion 300Aa is formed by the third outer edge portion 500a of the add-on guide rib 5001, which is installed as described in detail later. Similarly, the downstream portion 300Ab is formed by the third outer edge portion 500a of the add-on guide rib 5001, which is installed as described in detail later.

[0040] Specifically, as shown in Figures 5 and 7, the rib 303 has a first outer edge portion 303a on the side of the first guide portion 300A at its outer edge. In other words, the first outer edge portion 303a forms the first guide portion 300A of the flapper 3001 and also forms a part of the first transport path R1 on which the sheet can be guided. Furthermore, the first outer edge portion 303a has a curved portion 303ab that curves inward in a concave shape when viewed from the width direction, and straight portions 303aa and 303ac that extend in a straight line. As a result, when the sheet is in the first position P1 (see Figure 2(a)), the first outer edge portion 303a first guides the leading edge of the sheet being transported from below by contacting it at a gentle angle with the straight portion 303aa. After that, the first outer edge portion 303a changes the angle of the leading edge of the sheet with the curved portion 303ab so that it faces the direction of the first discharge roller pair 210. The leading edge of the sheet is then guided toward the first discharge roller pair 210 while moving away from the straight section 303ac. The portion formed by the first outer edges 303a of the multiple ribs 303 in the first guide section 300A can also be described as a virtual plane connecting these first outer edges 303a in the conveying direction and width direction.

[0041] On the other hand, the rib 303 has a second outer edge portion 303b on the side of the second guide portion 300B at its outer edge, and as shown in Figures 6 and 7, it extends over the entire outside of the main body portion 302A in the transport direction. In other words, the second guide portion 300B, which forms part of the second transport path R2, is composed of the second outer edge portion 303b of the rib 303 in ribs 303 where the add-on guide rib 5001, which will be described later, is not attached adjacent to it. In other words, when a sheet is transported along the second transport path R2, the sheet is configured to come into contact with the support portion 302 as little as possible. Note that the second guide portion 300B is formed by the fourth outer edge portion 500b of the add-on guide rib 5001, which will be described in more detail later.

[0042] As shown in Figure 7, the second outer edge portion 303b has, when viewed from the width direction, a first straight portion 303ba positioned upstream in the conveying direction, and a second straight portion 303bb that is continuously connected to the first straight portion 303ba and positioned downstream of the first straight portion 303ba in the conveying direction. As a result, when the flapper 3001 is in the second position P2, the second outer edge portion 303b guides the leading edge of the sheet being conveyed from below upward while contacting the first straight portion 303ba and the second straight portion 303bb. The portion formed by the second outer edge portions 303b of the multiple ribs 303 in the second guide portion 300B can also be said to be a virtual plane connecting these second outer edge portions 303b in the conveying direction and the width direction.

[0043] The flapper 3001, configured in the shape described above, is made of, for example, plastic resin to reduce weight. Furthermore, by forming multiple ribs 303 from the support portion 302 and configuring their outer edges to contact the sheet, a so-called comb-shaped sheet guide portion is formed, which is lighter than, for example, configuring the sheet to be guided by the outer surface of the support portion 302. Consequently, the switching control by the drive mechanism 900 described later can be accelerated, contributing to improved productivity of the printer 100.

[0044] [Configuration of the flapper's drive mechanism] Next, the drive mechanism 900, which drives the flapper 3001 to switch between the first position P1 and the second position P2, will be explained using Figure 8. Figure 8 is a cross-sectional view showing the drive mechanism of the flapper.

[0045] As shown in Figure 8, the drive mechanism 900 that drives and controls the switching of the flapper 3001 comprises a solenoid 901 having a plunger 902, a first arm 904, a second arm 907, and a spring 908. When energized by a command from a control unit (not shown), the solenoid 901 drives the plunger 902 in the direction of the upward arrow U in the figure. The first arm 904 is rotatably supported at one end by a pivot shaft 903, and an engagement shaft 906 is fixed to the other end, with a hook 904A formed thereon to which one end of the spring 908 is connected. Furthermore, it is connected to the plunger 902 near the center by a connecting shaft 905. The other end of the spring 908 is fixed to the frame (i.e., the printer body 101) that supports the drive mechanism 900. The second arm 907 has one end fixed to the support shaft 301 of the flapper 3001 and has an elongated hole 907A formed at the other end, and the engagement shaft 906 is slidably engaged with the elongated hole 907A.

[0046] In the drive mechanism 900 configured in this way, under the control of a control unit (not shown), when the plunger 902 of the solenoid 901 is not driven, the biasing force of the spring 908 causes the first arm 904 to be in a lower position and the second arm 907 to be in a lower position. In this state, since the second arm 907 to which the support shaft 301 is fixed is also in a lower position, the flapper 3001 is controlled to a first position P1 (see Figure 2(a)). When the plunger 902 of the solenoid 901 is driven upward in the direction of arrow U by the control of a control unit (not shown), the first arm 904 is driven upward in the direction of arrow V against the biasing force of the spring 908, and the engagement shaft 906 also rotates the second arm 907 upward. As a result, the support shaft 301 of the flapper 3001 fixed to the second arm 907 is rotated, and the flapper 3001 is controlled to a second position P2 (see Figure 2(b)).

[0047] [Add-on Guide Lib Configuration] Next, the structure of the add-on guide rib 5001 as a high-sliding member according to the first embodiment will be described with reference to Figures 5 to 7. The add-on guide rib 5001 is a component that can be retrofitted to the flapper 3001, and is made of a high-sliding material that has better sliding properties with the sheet than the material of the flapper 3001, particularly the material of the rib 303. For example, the add-on guide rib 5001 is made of fluoropolymer (PFA).

[0048] As shown in Figures 5 and 6, the add-on guide rib 5001 is positioned adjacent to the target rib 303A among the multiple ribs 303. Furthermore, as shown in Figure 7, the add-on guide rib 5001 is attached to the support portion 302 adjacent to the target rib 303A. The support portion 302 has a plate-shaped main body portion 302A formed in a triangular shape when viewed from the width direction, as described above. The add-on guide rib 5001 has a claw portion 500c that engages with one end 302Aa of the main body portion 302A, and a claw portion 500d that engages with the other end 302Ab. Thus, the add-on guide rib 5001 is attached to the support portion 302 by elastically deforming the claw portions 500c and 500d in the direction of transport (from upstream to downstream in the transport direction, from bottom to top in Figure 7) to hook and engage with the support portion 302. Furthermore, the add-on guide rib 5001 can be detached from the flapper 3001 by deforming its claw portions 500c and 500d to release any entanglement with the flapper 3001. In other words, the add-on guide rib 5001 is detachable from the flapper 3001.

[0049] In this embodiment, the add-on guide rib 5001 is described as being attached to the support portion 302 of the flapper 3001 from upstream to downstream in the conveying direction, but this is not the only configuration. In other words, if it is attached to the flapper 3001 from, for example, from downstream to upstream in the conveying direction, there is a risk of it coming off due to collision with the sheet. Therefore, the direction of attachment can be any direction other than the reverse flow direction (a direction other than the reverse flow direction) so as to reduce the possibility of it coming off.

[0050] When the add-on guide rib 5001 according to this embodiment is attached to the main body portion 302A adjacent to the target rib 303A, its outer edge is located outside the outer edge of the target rib 303A. That is, the third outer edge portion 500a of the add-on guide rib 5001 is substantially the same shape (similar shape) as the first outer edge portion 303a of the target rib 303A, and is configured to be located outside the first outer edge portion 303a. In other words, the third outer edge portion 500a is positioned outside the straight portion 303aa, the curved portion 303ab, and the straight portion 303ac of the first outer edge portion 303a. As a result, the third outer edge portion 500a constitutes a third guide portion that guides the sheet to the first transport path R1 when the flapper 3001 is in the first position P1. Furthermore, the portion formed by the third outer edges 500a of the multiple ribs 303 acting as the third guide section can be described as a virtual plane connecting these third outer edges 500a in the conveying direction and the width direction.

[0051] Similarly, the fourth outer edge portion 500b of the add-on guide rib 5001 has the same shape (similar shape) as the second outer edge portion 303b of the target rib 303A, and is configured to be located outside the second outer edge portion 303b. In other words, the fourth outer edge portion 500b is positioned outside the first straight portion 303ba and the second straight portion 303bb. As a result, the fourth outer edge portion 500b constitutes a fourth guide portion that guides the sheet to the second transport path R2 when the flapper 3001 is in the second position P2. The portion formed by the fourth outer edge portions 500b of the multiple ribs 303 acting as the fourth guide portion can also be described as a virtual plane connecting these fourth outer edge portions 500b in the transport direction and width direction.

[0052] In short, the third outer edge portion 500a forms part of the first transport path R1 at the outer edge of the add-on guide rib 5001 and forms part of the first guide portion 300A of the flapper 3001. Furthermore, the fourth outer edge portion 500b forms part of the second transport path R2 at the outer edge of the add-on guide rib 5001 and forms the second guide portion 300B of the flapper 3001.

[0053] Assume that the add-on guide rib 5001 configured in this way is attached to the flapper 3001 adjacent to the target rib 303A. Then, when the flapper 3001 is in the first position P1 and guiding the sheet to the first transport path R1, the leading edge of the sheet comes into contact with the third outer edge 500a of the add-on guide rib 5001, as shown by the solid line in Figure 2(a), and does not come into contact with the first outer edge 303a of the target rib 303A. As a result, when the sheet is guided along the first transport path R1, the leading edge of the sheet comes into contact with the add-on guide rib 5001, which is a highly sliding material, and is guided in this way, thereby reducing the risk of defects or streaks being formed on the sheet. The sheet, guided in contact with the third outer edge 500a of the add-on guide rib 5001, is then guided along the first transport path R1 toward the first discharge roller pair 210, as shown by the dotted line in Figure 2(a).

[0054] Furthermore, when the flapper 3001 is in the second position P2 and guiding the sheet to the second transport path R2, the leading edge of the sheet contacts the fourth outer edge 500b of the add-on guide rib 5001, as shown by the solid line in Figure 2(b), but does not contact the second outer edge 303b of the target rib 303A. As a result, even when the sheet is guided along the second transport path R2, it is guided in contact with the add-on guide rib 5001, which is a highly sliding material, thus reducing the risk of defects or streaks forming on the sheet. The sheet, guided in contact with the fourth outer edge 500b of the add-on guide rib 5001, is then guided along the second transport path R2 toward the second discharge roller pair 220 (see Figure 1), as shown by the dotted line in Figure 2(b).

[0055] Furthermore, the add-on guide rib 5001 configured as described above is not attached to all ribs 303, but only to the target rib 303A. This prevents the flapper 3001 from becoming unnecessarily heavy due to the attachment of the add-on guide rib 5001.

[0056] Furthermore, as described above, the add-on guide rib 5001 is positioned in the width direction when viewed from the conveying direction, overlapping with the roller portion 162a of the fixed outer roller 162. In other words, the sheet conveyed by the roller portion 162a of the fixed outer roller 162, which is located immediately upstream of the conveying direction of the flapper 3001, is configured to easily come into contact with the add-on guide rib 5001 rather than the rib 303. This reduces the risk of the sheet being pressed against the rib 303 by the roller portion 162a of the fixed outer roller 162, thereby reducing the possibility of defects or streaks being formed on the sheet.

[0057] [Positional relationship between add-on guide ribs and rollers] Next, the positional relationship between the add-on guide rib 5001 attached to the flapper 3001 according to the first embodiment and the roller 230 arranged in the first transport path R1 will be described. As described above, the multiple rollers 230 are arranged in two locations in the width direction so as to protrude from the opening G1Ca of the guide portion G1C of the first guide G1, as shown in Figures 3 and 4(b). The target rib 303A, which is located near the center in the width direction, and the add-on guide rib 5001 attached adjacent to the target rib 303A, are arranged in close proximity to the rollers 230 in the width direction, as shown in Figures 4(a) and 4(b). Therefore, the rollers 230 make it easier to slide the sheet, which will pass closer to the flapper 3001 than to the guide portion G1C of the first guide G1 in the first transport path R1, onto the add-on guide rib 5001, which has higher sliding properties than the rib 303. This reduces the risk of defects or streaks being formed on the sheet guided by the rollers 230.

[0058] Furthermore, as shown in Figures 2(a) and 7, in the downstream portion 300Ab facing the roller 230, the third outer edge portion 500a is positioned outside the first outer edge portion 303a of the rib 303. Therefore, when the flapper 3001 is in the first position P1, the sheet guided by the roller 230 can slide against the add-on guide rib 5002. Consequently, the sheet, which will pass closer to the flapper 3001 than the guide portion G1C of the first guide G1 in the first transport path R1 due to the roller 230, is more easily slid against the add-on guide rib 5002, which has higher sliding properties than the first outer edge portion 303a of the rib 303. This reduces the risk of defects or streaks forming on the sheet guided by the roller 230.

[0059] [Positional relationship between add-on guide ribs and cushioning material] Next, the positional relationship between the add-on guide rib 5001 and the cushioning member 600 will be explained. As mentioned above, if the add-on guide rib 5001 is attached to all the ribs 303, the flapper 3001 may become heavy, potentially worsening the productivity of the printer 100. Therefore, as shown in Figures 5 and 6, in this embodiment, the add-on guide rib 5001 is attached adjacent to four target ribs 303A in the width direction. Two of these four target ribs 303A are positioned so that their ends are slightly inside the smallest width size that the printer 100 can print on (e.g., postcard size). The other two of these four target ribs 303A are positioned so that their ends are slightly inside the largest width size that the printer 100 can print on (e.g., A4 size). In other words, out of the 22 ribs 303, four target ribs 303A are selected according to the smallest and largest sheet sizes.

[0060] On the other hand, as shown in Figures 3, 4(a), and 4(b), as described above, the guide portion G1B of the first guide G1 has multiple ribs G1BR arranged in the width direction. Furthermore, cushioning members 600 made of sponge or the like are arranged at intervals in the width direction on the guide portion G1B of the first guide G1 so as to fit between these ribs G1BR. As shown in Figure 2(b), these cushioning members 600 prevent the ribs 303 of the flapper 3001 from coming into contact (colliding) with the flapper 3001 when the flapper 3001 is switched to the second position P2, thus preventing noise from being generated by the flapper 3001 directly colliding with the first guide G1.

[0061] As shown in Figure 4(a), these cushioning members 600 are positioned to contact a rib 303 different from the target rib 303A. In other words, among the multiple ribs 303, the rib offset in the width direction (Y direction) from the position where the cushioning member 600 is positioned is selected as the target rib 303A. The target rib 303A, whose position is selected in the width direction in this way, remains in a different position in the width direction from the cushioning member 600 even when the flapper 3001 is switched to the second position P2. That is, the add-on guide rib 5001 attached to the target rib 303A is also positioned in a position offset in the width direction from the cushioning member 600, and the add-on guide rib 5001 and the cushioning member 600 do not come into contact when the flapper 3001 is switched to the second position P2. This makes it possible to avoid increased noise caused by contact between the add-on guide rib 5001 and the buffer member 600 when the flapper 3001 is switched to the second position P2, and thus reduce noise during the switching of the flapper 3001. An example has been given in which the buffer member 600 is positioned so as to abut against one rib 303 that is different from the target rib 303A, without contacting the add-on guide rib 5001. However, for example, the buffer member 600 may be positioned so as to simultaneously contact two adjacent ribs 303 without contacting the add-on guide rib 5001.

[0062] <Second Embodiment> Next, a second embodiment, which is a modified version of the first embodiment described above, will be explained with reference to Figure 9. Figure 9 is a cross-sectional view showing the positional relationship between the add-on guide rib according to the second embodiment, the target rib to which it is attached, and the roller. In this explanation of the second embodiment, the same reference numerals are used for parts similar to those in the first embodiment, and their descriptions are omitted.

[0063] In this second embodiment, the shape of the add-on guide rib 5002 is modified compared to the add-on guide rib 5001 according to the first embodiment. Specifically, as shown in Figure 9, in the add-on guide rib 5002 according to the second embodiment, the third outer edge 500a of the add-on guide rib 5002 is positioned inward at the downstream portion 300Ab of the first guide portion 300A of the flapper 3001. In other words, at the downstream portion 300Ab of the first guide portion 300A, the rib 303 of the flapper 3001 is outside the third outer edge 500a of the add-on guide rib 5002, and the straight portion 303ac, which is the outer edge of the rib 303, is formed to extend downstream in the conveying direction.

[0064] The sheet, guided by contact with the third outer edge 500a of the add-on guide rib 5001, is guided along the first transport path R1 toward the first discharge roller pair 210, as shown by the dotted line in Figure 2(a). At this time, the third outer edge 500a of the add-on guide rib 5001 is not positioned outside the straight section 303ac of the rib 303 of the flapper 3001. That is, if the rear end of the sheet being transported by the first discharge roller pair 210 were to slide only on the four add-on guide ribs 5001 in the width direction, there is a risk of streaks being formed. However, the rear end of this sheet is transported by the straight sections 303ac of multiple (22) ribs 303 (including the target rib 303A), meaning that the force of contact is distributed more evenly than if the rear end of the sheet were to slide on the four add-on guide ribs 5001. Therefore, the risk of streaks forming on the sheet can be reduced, and the flow of the sheet conveyed by the first discharge roller pair 210 can be improved.

[0065] Furthermore, the third outer edge 500a of the add-on guide rib 5001 is not positioned outside the downstream portion 300Ab. This configuration reduces the risk of the add-on guide rib 5001 colliding with the roller 230 and damaging each other during assembly when attaching the add-on guide rib 5001 to the flapper 3001, thus improving ease of assembly.

[0066] <Third Embodiment> Next, a third embodiment, which is a modified version of the first and second embodiments described above, will be explained with reference to Figure 10. Figure 10 is a cross-sectional view showing the positional relationship between the add-on guide rib according to the third embodiment, the target rib on which it is attached, and the roller. In this explanation of the third embodiment, the same reference numerals are used for parts similar to those in the first and second embodiments, and their descriptions are omitted.

[0067] In this third embodiment, the shape of the add-on guide rib 5003 is modified compared to the add-on guide rib 5001 according to the first embodiment. Specifically, as shown in Figure 10, in the add-on guide rib 5003 according to the third embodiment, the third outer edge 500a of the add-on guide rib 5003 is positioned outward at the downstream portion 300Ab of the first guide portion 300A of the flapper 3001. On the other hand, in the upstream portion 300Aa of the first guide portion 300A of the flapper 3001, the add-on guide rib 5003 is positioned inward from the first outer edge 303a (straight portion 303aa and curved portion 303ab) of the target rib 303A.

[0068] Therefore, when the flapper 3001 is in the first position P1, the leading edge of the sheet being conveyed by the fixed roller pair 160 comes into contact with the first outer edge 303a of all ribs 303 (including the target rib 303A) that can come into contact in the width direction. Accordingly, in the configuration of this third embodiment, the force of contact is distributed more evenly than when the leading edge of the sheet comes into contact with the four add-on guide ribs 500 as in the first embodiment, and the occurrence of damage to the leading edge of the sheet can be reduced.

[0069] Furthermore, in the add-on guide rib 5003, similar to the second embodiment, the third outer edge 500a of the add-on guide rib 5003 is positioned outward at the downstream portion 300A of the first guide portion 300A of the flapper 3001. As a result, the sheet guided by the roller 230 can slide against the add-on guide rib 5003. Consequently, the sheet, which will pass closer to the flapper 3001 than the guide portion G1C of the first guide G1 in the first transport path R1 due to the roller 230, can be more easily slid against the add-on guide rib 5003, which has higher sliding properties than the first outer edge 303a of the rib 303. This reduces the risk of defects or streaks forming on the sheet guided by the roller 230.

[0070] In this third embodiment, the add-on guide rib 5003 is positioned on the side of the second guide portion 300B of the flapper 3001 so that it is generally positioned outside the second outer edge portion 303b of the target rib 303A. However, the configuration is not limited to this, and the fourth outer edge portion 500b of the add-on guide rib 5003 may be positioned inward from the second outer edge portion 303b upstream of the second guide portion 300B in the conveying direction. This ensures that when the flapper 3001 is in the second position P2, the leading edge of the sheet being conveyed by the fixed roller pair 160 contacts the second outer edge portion 303b of all ribs 303 (including the target rib 303A) that can contact it in the width direction. This configuration disperses the force of contact more effectively than when the leading edge of the sheet contacts four add-on guide ribs 500 as in the first embodiment, thereby reducing the occurrence of damage to the leading edge of the sheet.

[0071] <Fourth Embodiment> Next, a fourth embodiment, which is a modified version of the first to third embodiments described above, will be explained with reference to Figure 11. Figure 11 is a cross-sectional view showing the positional relationship between the add-on guide rib according to the fourth embodiment, the target rib on which it is attached, and the roller. In this explanation of the fourth embodiment, the same reference numerals as in the first to third embodiments will be used for the same parts, and their explanations will be omitted.

[0072] In this fourth embodiment, the shape of the flapper 3002 is partially modified compared to the flapper 3001 according to the first to third embodiments. In addition, the shape of the add-on guide rib 5004 is also modified to match the shape of the flapper 3002.

[0073] More specifically, as shown in Figure 11, in the flapper 3002 according to the fourth embodiment, when viewed from the width direction, the upstream portion 300Aa of the first guide portion 300A is formed in a straight line, and the downstream portion 300Ab is formed in a concave curved shape. That is, the first outer edge portion 303a of the rib 303 has, when viewed from the width direction, a straight portion 303ad formed in a straight line upstream in the conveying direction, and a concave curved portion 303ae formed downstream in the conveying direction.

[0074] Furthermore, the third outer edge portion 500a of the add-on guide rib 5004 according to the fourth embodiment has, when viewed from the width direction, a straight portion 500aa formed in a straight line upstream in the conveying direction and a curved portion 500ab formed in a concave shape downstream in the conveying direction. That is, in the upstream portion 300Aa of the first guide portion 300A of the flapper 3002, the straight portion 500aa of the add-on guide rib 5004 is positioned inward from the straight portion 303ad of the first outer edge portion 303a of the target rib 303A. Also, in the downstream portion 300Ab of the first guide portion 300A of the flapper 3002, the curved portion 500ab of the add-on guide rib 5002 is positioned outward from the curved portion 303ae of the first outer edge portion 303a of the target rib 303A.

[0075] Therefore, when the flapper 3001 is in the first position P1, the leading edge of the sheet being conveyed by the fixed roller pair 160 comes into contact with the straight portion 303ad of the first outer edge 303a of all ribs 303 (including the target rib 303A) that can come into contact in the width direction. Accordingly, in the configuration of this fourth embodiment, the force of contact is distributed more evenly than when the leading edge of the sheet comes into contact with the four add-on guide ribs 500 as in the first embodiment, and the occurrence of damage to the leading edge of the sheet can be reduced.

[0076] Then, the leading edge of the sheet that has come into contact with the straight portion 303ad of the first outer edge 303a of the rib 303 (including the target rib 303A) is carried further and slides against the curved portion 500ab of the add-on guide rib 5002 of the add-on guide rib 5004. As a result, the sheet is smoothly guided toward the first discharge roller pair 210.

[0077] Furthermore, in the add-on guide rib 5004, similar to the second and third embodiments, the curved portion 500ab of the third outer edge 500a of the add-on guide rib 5004 is positioned outward at the downstream portion 300A of the first guide portion 300A of the flapper 3002. As a result, the sheet guided by the roller 230 can slide against the add-on guide rib 5004. Consequently, the sheet, which will pass closer to the flapper 3002 than the guide portion G1C of the first guide G1 in the first transport path R1 due to the roller 230, can be more easily slid against the add-on guide rib 5004, which has higher sliding properties than the curved portion 303ae of the target rib 303A. This reduces the risk of defects or streaks forming on the sheet guided by the roller 230.

[0078] <Fifth Embodiment> Next, a fifth embodiment, which is a modified version of the second embodiment described above, will be explained with reference to Figure 12. Figure 12 is a cross-sectional view showing the positional relationship between the add-on guide rib according to the fifth embodiment, the target rib to which it is attached, and the roller. In this explanation of the fifth embodiment, the same reference numerals as in the second embodiment will be used, and their explanations will be omitted.

[0079] In this fifth embodiment, the relative positional relationship between the flapper 3001 and the roller 230 is changed. For example, an opening can be formed in the guide portion G1B of the first guide G1 (see Figure 3), and the roller 230 can be positioned to protrude from the guide portion G1B.

[0080] In this configuration, as shown in Figure 12, the roller 230 is positioned opposite the upstream portion 300Aa of the first guide portion 300A of the flapper 3001. Therefore, when the flapper 3001 is in the first position P1, the sheet guided by the roller 230 can slide against the third outer edge portion 500a of the add-on guide rib 5001. Consequently, the sheet, which will pass closer to the flapper 3001 than the guide portion G1B of the first guide G1 in the first transport path R1 due to the roller 230, is more easily slid against the add-on guide rib 5001, which has higher sliding properties than the first outer edge portion 303a of the target rib 303A. This reduces the risk of defects or streaks forming on the sheet guided by the roller 230.

[0081] Furthermore, in the downstream portion 300Ab of the first guide portion 300A of the flapper 3001, the third outer edge portion 500a of the add-on guide rib 5001 is not formed, and the sheet is guided by sliding along the first outer edge portion 303a of the rib 303. In this case, since the roller 230 does not face the straight portion 303ac of the first outer edge portion 303a of the rib 303, the sheet does not pass as close to it as, for example, when the roller 230 is arranged facing it. Therefore, even if the sliding properties of the first outer edge portion 303a of the rib 303 are lower than those of the add-on guide rib 5001, the risk of defects or streaks being formed on the sheet is reduced.

[0082] In addition, in the add-on guide rib 5001 shown in the first embodiment, the roller 230 may be positioned opposite the upstream portion 300Aa of the first guide portion 300A of the flapper 3001.

[0083] <Possibility of other embodiments> In the first to fifth embodiments described above, the add-on guide rib 500 was positioned adjacent to the target rib 303A, and configured so that the outer edge of the add-on guide rib 500 was outside the outer edge of the target rib 303A. However, the configuration is not limited to this, and the add-on guide rib may be attached (joined) to the target rib so as to cover the outer edge of the target rib. Furthermore, the entire add-on guide rib 5001 does not need to have high sliding properties. That is, it is sufficient if at least the third outer edge portion 500a of the add-on guide rib 5001 that contacts the sheet has higher sliding properties with respect to the sheet than the material of the flapper 3001. In addition, a member with high sliding properties was given as an example of the add-on guide rib 5001. However, the add-on guide rib 5001 does not necessarily have to be a member with higher sliding properties than the flapper 3001. That is, the add-on guide rib 5001 should be such that, when attached to the flapper 3001, it can provide stable sheet guidance or reduce damage to the sheet.

[0084] Furthermore, in the first to fifth embodiments, an arrangement was described in which the add-on guide ribs 500 (target ribs 303A) were placed at four locations in the width direction, and the cushioning members 600 were placed at three locations in the width direction, and these were arranged to be offset from each other. However, the number and arrangement of these can be any number and any arrangement. In other words, as long as the add-on guide ribs 500 and the cushioning members 600 do not come into contact (collide) with each other when the flapper 300 is switched, and the ribs 303 and the cushioning members 600 come into contact, the number and arrangement can be any.

[0085] Furthermore, in the first to fifth embodiments, a structure was described in which the add-on guide rib 500 is attached to the flapper 300 by hooking the claw portions 500c and 500d onto the main body portion 302A of the support portion 302 of the flapper 300. However, the structure is not limited to this, and it may also be attached using an elastically deformable structure such as a snap-fit, or even by bonding with an adhesive.

[0086] Furthermore, in the first to fifth embodiments, the add-on guide rib 500 was described having a third outer edge portion 500a and a fourth outer edge portion 500b, that is, sliding with the sheet at both the first guide portion 300A and the second guide portion 300B of the flapper 300. However, it is not limited to this, and for example, the add-on guide rib 500 may have only one of the third outer edge portion 500a and the fourth outer edge portion 500b. In other words, the add-on guide rib 500 only needs to form at least one of the following: a third outer edge portion 500a that can guide the sheet to the first transport path R1 when it is in the first position P1, and a fourth outer edge portion 500b that can guide the sheet to the second transport path R2 when it is in the second position P2.

[0087] Furthermore, in the first to fifth embodiments, a flapper 300 was described in which a plurality of ribs 303 have a first outer edge portion 303a and a second outer edge portion 303b, that is, the flapper 300 is slidable with the sheet at both the first guide portion 300A and the second guide portion 300B. However, it is not limited to this, and for example, a rib 303 may have only one of the first outer edge portion 303a and the second outer edge portion 303b. In other words, the flapper 300 only needs to have a first outer edge portion 303a that can guide the sheet to the first transport path R1 when it is in the first position P1, and a second outer edge portion 303b that can guide the sheet to the second transport path R2 when it is in the second position P2, formed by the outer edges of at least a plurality of ribs 303.

[0088] Furthermore, in the first, third to fifth embodiments, a case was described in which the third outer edge 500a of the add-on guide rib 500 is located outward from a part of the first guide portion 300A (first outer edge portion 303a) of the flapper 300. Specifically, in the first and fifth embodiments, a case was described in which the third outer edge 500a of the add-on guide rib 500 is located outward from the upstream portion 300Aa (first outer edge portion 303a of the rib 303) of the first guide portion 300A of the flapper 300. Furthermore, in the third and fourth embodiments, a case was described in which the third outer edge 500a of the add-on guide rib 500 is located outward from the downstream portion 300Ab of the first guide portion 300A of the flapper 300. However, the part of the first guide portion 300A is not limited to either the upstream portion 300Aa or the downstream portion 300Ab. For example, the third outer edge 500a of the add-on guide rib 500 may be shaped such that it is positioned outside the first guide section 300A at two or more locations in the transport direction. Also, the boundary between the upstream section 300Aa and the downstream section 300Ab may be at any position; in other words, the portion where the third outer edge 500a of the add-on guide rib 500 is located on the outside may be defined as the upstream section 300Aa or the downstream section 300Ab. Furthermore, if the third outer edge 500a of the add-on guide rib 500 is located outside the upstream section 300Aa, it may also protrude outside a portion of the downstream section 300Ab. In other words, in this case, the third outer edge 500a of the add-on guide rib 500 should be positioned outside the upstream section 300Aa when viewed from the width direction, and not outside at least a portion of the downstream section 300Ab. Similarly, if the third outer edge 500a of the add-on guide rib 500 is located outside the downstream portion 300Ab, the third outer edge 500a of the add-on guide rib 500 may also protrude outside a portion of the upstream portion 300Aa. In other words, in this case, the third outer edge 500a of the add-on guide rib 500 should be positioned outside the downstream portion 300Ab when viewed from the width direction, and not outside at least a portion of the upstream portion 300Aa.

[0089] Furthermore, in the first to fifth embodiments, the first transport path R1 is a transport path toward the first discharge roller pair 210, and the second transport path R2 is a transport path toward the second discharge roller pair 220, meaning that the first transport path R1 is located below the second transport path R2. However, these relationships may be reversed, and furthermore, for example, one of the first and second transport paths may be a transport path that discharges the sheet to the outside of the printer 100, and the other may be a re-transport path that re-transports the sheet to the image forming unit 102. In other words, the first and second transport paths may be any transport paths, and the flapper 300 may be located at any branch of the transport path.

[0090] Furthermore, in the first to fifth embodiments, the buffer member 600 was described as being positioned to collide with the rib 303 when the flapper 300 is switched to the second position P2. However, the buffer member is not limited to this, and may be positioned to collide with the rib 303 when the flapper 300 is switched to the first position P1. Moreover, the buffer member may be positioned on both sides of the rotational direction of the flapper 300 when viewed from the width direction, so as to collide with the rib 303 regardless of which position the flapper 300 is switched to.

[0091] Furthermore, in the first to fifth embodiments, the drive mechanism 900 was described in which the flapper 300 is biased to a first position P1 by the biasing force of a spring 908 and switched to a second position P2 by the drive of a solenoid 901. However, the invention is not limited to this, and it is also acceptable for the flapper 300 to be biased to a second position P2 by the biasing force of a spring 908 and switched to a first position P1 by the drive of a solenoid 901. In particular, in this case, the cushioning member may be positioned to collide with the rib 303 when the flapper 300 is switched to the first position P1.

[0092] Furthermore, in the first to fifth embodiments, the target rib 303A was described as being positioned in close proximity to the roller 230, but this proximity does not necessarily mean that there are no other ribs 303 in between. That is, the target rib 303A can be any rib adjacent to the roller 230 in the width direction, or any rib positioned close by one or more ribs in between.

[0093] Furthermore, in the first to fifth embodiments, an arrangement was shown in which the flapper 3001 and the roller 230 do not overlap when viewed from the width direction when positioned in the second position. However, the flapper 3001 and the roller 230 may be arranged so that they overlap when viewed from the width direction when positioned in the second position. In such a case, where the flapper 3001 and the roller 230 overlap when viewed from the width direction, one roller 230 should be positioned between two of the multiple ribs 303 in the width direction. Also, in this case, the add-on guide rib attached to the flapper 3001 also overlaps with the roller 230 when viewed from the width direction. The roller 230 is then positioned between the target rib 303A (the rib to which the add-on guide rib is adjacent or the rib to which the add-on guide rib is joined) and the rib adjacent to the target rib. In this case, it is preferable that the roller 230 and the target rib are adjacent in the width direction, that is, that there is no other rib 303 between the roller 230 and the target rib in the width direction. In other words, it is preferable to configure the roller 230 and the add-on guide rib to be adjacent in the width direction, that is, so that none of the multiple ribs are positioned between the roller 230 and the add-on guide rib in the width direction.

[0094] Furthermore, in the first to fifth embodiments, the sheet transport unit 104, as an example of a sheet transport device, was described as being located downstream of the image forming unit 102 in the transport direction and transporting the sheet to the outside of the printer 100. However, it is not limited to this, and any sheet transport device that transports sheets is acceptable. That is, the sheet transport device may be, for example, the part that supplies the sheet to the image forming unit. Moreover, the sheet transport device may be, for example, the part that transports sheets in a large-capacity feeding deck, inspection device, finisher, reversing device, binding device, bookbinding device, folding device, cutting device, perforation device, etc., or the device itself. [Explanation of symbols]

[0095] 100…Printer (image forming apparatus) / 102…Image forming unit / 104…Sheet transport unit (sheet transport device) / 150…Fuser (transport unit) / 160…Post-fusing roller pair (transport unit) / 162…Post-fusing outer roller (upstream roller) / 162a…Roller part (contact rotating part) / 162b…Support shaft / 180…Upstream transport roller pair (transport unit) / 190…Downstream transport roller pair (transport unit) / 210…First discharge roller pair (transport unit) / 220…Second discharge roller pair (transport unit) / 230…Roller (rotating body) / 300…Flapper (switching member) / 300A…First guide unit / 300Aa…Upstream unit / 300A b...downstream section / 300B...second guide section / 302...support section / 303...rib (first rib) / 303A...target rib / 303ab...curved section / 303aa...straight section / 500...add-on guide rib (high sliding member, mounting member) / 500a...third outer edge section (sliding part, third guide section) / 600...cushioning member (sponge) / G1...first guide (guide member) / G1B...guide section (fourth guide section) / G1BR...rib (second rib) / G1C...guide section (fifth guide section) / G1Ca...opening / JN...branch section / P1...first position / P2...second position / R1...first transport path / R2...second transport path / S...sheet

Claims

1. A conveying unit that transports the sheets, A first transport path that guides the sheet being transported by the transport unit, A second transport path branches off from the first transport path at the branching point and guides the sheet being transported by the transport section, A switching member that can switch between a first position that guides the conveyed sheet to the first conveying path downstream of the branching point in the conveying direction, and a second position that guides the conveyed sheet to the second conveying path, A plurality of buffer members that contact and buffer the switching member when the switching member is switched to the second position, The system comprises a plurality of high-sliding members that can be attached to the switching member and have higher sliding properties against the sheet than the switching member, The switching member has a support portion arranged such that the width direction perpendicular to the conveying direction is the longitudinal direction, and a plurality of ribs supported by the support portion and arranged in line in the width direction. The switching member has, at least by the outer edges of the plurality of ribs, a first guide portion that can guide the sheet to the first transport path when in the first position, and a second guide portion that can guide the sheet to the second transport path when in the second position. Each of the plurality of high-sliding members has a sliding portion that can slide on the sheet, is attached to a target rib among the plurality of ribs, and is positioned such that the sliding portion is located outside the outer edge of the target rib, thereby forming a third guide portion that can guide the sheet along the first transport path when in the first position, and is positioned offset from the buffer member in the width direction. A sheet conveying device characterized by the following features.

2. The system includes a guide member positioned opposite the switching member, capable of guiding the sheet along the first transport path, and on which the cushioning member is positioned. The sheet conveying device according to feature 1.

3. The aforementioned rib is the first rib, The guide member is positioned such that a portion of it overlaps with the first rib of the switching member in the second position when viewed from the width direction, and has a plurality of second ribs that form a fourth guide portion on their outer edges capable of guiding a sheet along the first transport path when the switching member is in the first position. Each of the plurality of buffer members is positioned between the plurality of second ribs in the width direction, The sheet conveying device according to feature 2.

4. The guide member has a plurality of openings arranged in the width direction and a fifth guide portion capable of guiding the sheet along the first transport path. The system comprises a plurality of rotating bodies that protrude from each of the plurality of openings and are rotatable while in contact with the sheet. The sheet conveying device according to feature 3.

5. The fifth guide section is positioned downstream of the fourth guide section in the conveying direction. The sheet conveying device according to feature 4.

6. The sliding portion of the high sliding member is not positioned opposite the rotating body when viewed from the width direction. The sheet conveying device according to feature 4.

7. The target rib is one of the plurality of ribs that is positioned in close proximity to the rotating body in the width direction. The sheet conveying device according to feature 4.

8. The conveying unit has a plurality of contact rotating parts that are spaced apart in the width direction and come into contact with the sheet, and a support shaft that supports these contact rotating parts, and has an upstream roller that is positioned adjacent to the upstream of the switching member in the conveying direction. The target rib is one of the plurality of ribs that is positioned to overlap with the contact rotating portion in the width direction when viewed from the conveying direction. The sheet conveying device according to feature 4.

9. The sliding portion of the high sliding member is positioned so as to be located outside a part of the first guide portion in the conveying direction. The sheet conveying device according to feature 1.

10. The first guide section has an upstream section and a downstream section located downstream of the upstream section in the conveying direction, The sliding portion of the high sliding member is positioned so as viewed from the width direction that it is located outside the upstream portion and not outside at least a portion of the downstream portion. The sheet conveying device according to feature 9.

11. The first guide section has an upstream section and a downstream section located downstream of the upstream section in the conveying direction, The sliding portion of the high sliding member is positioned so as viewed from the width direction, it is located outside the downstream portion and is not positioned outside at least a portion of the upstream portion. The sheet conveying device according to feature 9.

12. The first guide portion has a curved portion that is concave when viewed from the width direction and a straight portion that is straight, The sliding portion of the high sliding member is positioned so as viewed from the width direction, it is located outside the curved portion, and is not positioned outside at least a portion of the straight portion. The sheet conveying device according to feature 1.

13. Each of the aforementioned multiple high-sliding members is mounted on the switching member from a direction different from the reverse flow direction, which is from downstream to upstream in the conveying direction. The sheet conveying device according to feature 1.

14. A conveying unit that transports the sheets, A first transport path that guides the sheet being transported by the transport unit, A second transport path branches off from the first transport path at the branching point and guides the sheet being transported by the transport section, A switching member equipped with multiple ribs, which can be switched between a first position that guides the conveyed sheet to the first conveying path downstream of the branching section in the conveying direction, and a second position that guides the conveyed sheet to the second conveying path, A sponge that contacts the switching member when the switching member is switched to the second position, The switching member comprises a mounting member that can be attached to the switching member, When the switching member is in the first position, the ribs of the switching member and the mounting member attached to the switching member guide the sheet to the first transport path. The sponge is positioned so as not to come into contact with the mounting member, but to come into contact with at least one of the plurality of ribs. A sheet conveying device characterized by the following features.

15. The mounting member can be attached to any of the plurality of ribs, The mounting member is attached to the switching member such that a portion of the mounting member is located outside the outer edge of the rib to which the mounting member is attached. The sponge is positioned so as to abut against the ribs among the plurality of ribs to which the mounting member is not attached. The sheet conveying device according to feature 14.

16. It is equipped with a rotating body that can rotate in contact with the seat, The mounting member overlaps with the rotating body when viewed from the width direction perpendicular to the conveying direction, The rotating body is arranged so as to be adjacent to the mounting member in the width direction. The sheet conveying device according to feature 14.

17. A sheet conveying device according to claims 1 to 16, It comprises an image forming unit that forms an image on a sheet, An image forming apparatus characterized by the following:

Images