JP2009113900A - Paper guide member, discharging and conveying device, and image forming apparatus using these - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper guide member and a discharging and conveying device capable of conveying a paper favorably without or hardly without bringing the paper into contact with at least the paper guide member disposed inside the curve of a paper path, in the paper path for conveying the paper along the path curved in the definite direction, and to provide an image forming apparatus using these. <P>SOLUTION: The paper guide member is disposed inside the curve of the paper path provided for conveying paper along the path curved in the definite direction, wherein a conveying guide portion facing the paper path is formed in a shape depressed in the direction opposite to the curve of the paper path. The discharging and conveying device includes the paper guide member disposed inside the curve of the paper path provided for conveying paper fed from a fixing device provided for fixing an unfixed image onto the paper to a discharge port, along the path curved in the definite direction, with the conveying guide portion facing the paper path being formed in a shape depressed in the direction opposite to the curve of the paper path. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet guide member, a discharge conveyance device, and an image forming apparatus using them.

  As a paper guide member installed inside the curved direction of the paper conveyance path for conveying the paper along a curved path in a certain direction, for example, one applied to an image forming apparatus such as a printer, a copying machine, a facsimile machine, etc. The following are known.

  Of the guide means for guiding the transfer material that has passed through the fixing means along a slightly curved (substantially linear) path, as a guide means (reference numeral 38) installed inside the curved direction, a linear shape is used. There is one provided with a rib on which a guide surface is formed (Patent Document 1).

  In addition, it is installed inside a sliding contact member that guides a sheet conveyed along a path (slightly curved) in a direction refracted in the apparatus after image formation (for example, after fixing). As the sliding contact member (symbol 10), there is one in which the sliding contact surface is formed in an arc surface that is curved in the same direction as the bending direction (Patent Document 2).

  Further, as a sheet guide installed inside the bending direction of the sheet conveyance path for conveying the recording sheet that has passed through the fixing device along the curved path, the guide portion is bent in the same direction as the bending direction. There exists what was formed in the shape (patent document 3).

  Furthermore, as a conveyance guide (reference numeral 41) installed on the inner side of the bending direction of the sheet conveyance path for conveying the sheet that has passed through the fixing device along the curved path, the guide portion has the same direction as the bending direction. There are some which are formed in a shape that becomes convex (Patent Document 4).

JP-A-6-118818 (FIGS. 1 and 2) JP-A-10-273252 (FIGS. 1 and 2) JP 2003-76084 A (FIG. 2) Japanese Patent Laying-Open No. 2006-219205 (FIG. 2)

  According to the present invention, in a paper transport path for transporting a paper (sheet-like recording medium or the like) along a path that curves in a certain direction, the paper is installed at least inside the curving direction of the paper transport path. It is an object of the present invention to provide a paper guide member, a discharge transport device, and an image forming apparatus using them, which can be transported satisfactorily with little or no contact with the paper guide member.

  The sheet guide member of the present invention (A) is installed inside the curved direction of the sheet conveyance path for conveying the sheet along a path curved in a certain direction, and has a conveyance guide portion facing the sheet conveyance path. It is formed in a shape recessed in a direction opposite to the bending direction.

  The discharge conveying apparatus according to the present invention (B1) has a curved sheet discharge path for conveying a sheet fed from a fixing apparatus that fixes an unfixed image onto the sheet to a discharge port along a curved path in a certain direction. On the inside, a paper guide member is provided in which a conveyance guide portion facing the paper discharge path is formed in a shape recessed in a direction opposite to the curving direction.

  In addition, the discharge conveyance apparatus of the present invention (B2) has a discharge roll that rotates and feeds the paper from the discharge port in the discharge conveyance apparatus of the above-mentioned invention B1, and the paper feed speed of the discharge roll is higher than that of the discharge roll. In this case, the speed is set to be higher than the paper feed speed of the transport driving means that first exists on the upstream side in the transport direction of the paper discharge path.

  Further, the discharge transport apparatus of the present invention (B3) has a function of switching the paper feed direction by the reverse rotation of the discharge roll in the discharge transport apparatus of the above invention B1 or B2, and the paper guide member of the discharge roll A switching guide member, which is installed at a position on the paper introduction side and switches and guides the transport destination of the paper transported by the reverse rotation of the discharge roll, the switching guide portion obliquely intersects the transport guide portion of the paper guide member. Therefore, it is installed so as to be displaced in a continuous state.

  Further, the discharge conveyance device of the present invention (B4) is the discharge conveyance device according to any one of the above-mentioned inventions B1 to B3, wherein the sheet fed from the fixing device between the fixing device and the discharge port is fed to the sheet conveyance path. The sheet guide member is provided between the warp correcting means and the discharge port.

  The image forming apparatus of the present invention (C1) has a paper transport path for transporting the paper along a path that curves in a certain direction, and the paper transport path of the invention A1 is inside the curving direction. A sheet guide member is arranged.

  The image forming apparatus of the present invention (C2) includes an image forming apparatus that forms an unfixed image on a sheet, a fixing apparatus that fixes an unfixed image formed by the image forming apparatus on the sheet, and the inventions B1 to B1. It has one of the discharge conveying apparatuses of B4.

  According to the sheet guide member of the invention A, compared with the case of not having the configuration of the invention, in the sheet conveyance path of the path curved in a certain direction, the sheet is fed at least in the bending direction of the sheet conveyance path. It can be transported satisfactorily with little or no contact with the paper guide member installed inside.

  According to the discharge conveyance device of the above invention B1, compared with the case where it does not have the configuration, the paper conveyance route sent out from the fixing device in the paper discharge route of the path curved in a fixed direction between the fixing device and the discharge port. The sheet transported via the sheet can be transported satisfactorily without contact with or hardly in contact with the sheet guide member installed at least inside the curving direction of the sheet discharge path.

  In the discharge conveying device of the above-described invention B2, compared with the case where the configuration is not provided, the sheet sent out from the fixing device and conveyed via the sheet conveying path is disposed outside the curved direction of the sheet discharging path. The contact with the sheet guide member is eliminated or reduced.

  In the discharge conveyance device of the above invention B3, the conveyance guide portion of the sheet guide member installed at least inside the curved direction of the sheet discharge path has the discharge roll reversely rotated as compared with the case without the configuration. It can be used as a portion that guides the leading edge of the paper when being conveyed, and the leading edge of the paper that is guided by the conveyance guiding portion can finally be smoothly delivered to the switching guide member.

  In the discharging and conveying apparatus of the invention B4, the sheet after passing through the warp correcting means is at least in the curved direction of the sheet discharge path between the warp correcting means and the discharge port, as compared with the case without the configuration. It can be transported satisfactorily with little or no contact with the paper guide member installed inside.

  According to the image forming apparatus of the invention C1, compared with the case where the configuration is not provided, in the sheet conveyance path of the path curved in a certain direction, the sheet is at least inside the curve direction of the sheet conveyance path. It is transported satisfactorily with little or no contact with the installed paper guide member, and the occurrence of problems such as paper contamination and paper damage when contacting the paper guide member can be eliminated or reduced.

  According to the image forming apparatus of the invention C2, compared with the case where the configuration is not provided, in the sheet discharge path of the path curved in a fixed direction between the fixing apparatus and the discharge port, the sheet conveyance path is fed from the fixing apparatus. The sheet transported via the sheet is transported satisfactorily with little or no contact with the sheet guide member installed at least inside the curved direction of the sheet discharge path. It is possible to eliminate or reduce the occurrence of problems such as image disturbance, paper contamination, and paper damage when contacted.

  FIG. 1 is an explanatory diagram showing a main part of a sheet guide member 1, a discharge transport device 2, and an image forming apparatus 100 using the same according to an embodiment of the present invention.

  In FIG. 1, reference numeral 110 denotes an apparatus main body including a support frame and an exterior cover of the image forming apparatus 100. Reference numeral 120 denotes an image forming apparatus that forms a toner image as an unfixed image and transfers the toner image to a sheet 9. Is a fixing device for fixing the toner image transferred by the image forming device 120 to the paper 9. Further, reference numeral PR1 is a paper feed path for transporting and feeding the paper 9 from a paper feeding device (not shown) to the image forming apparatus 120, and reference numeral PR2 is transporting the paper 9 sent from the fixing device 130 to the discharge port 112 of the apparatus main body 110. The paper discharge path, the sign PR3, is formed again in the image forming apparatus 120 (actually, the joining point of the paper feed path PR1) with the front and back surfaces of the paper 9 sent out from the fixing device 130 turned on at the time of double-sided image formation. A reverse retransmission path 113 for conveying the sheet 9 is a paper discharge container for storing the sheets 9 discharged from the discharge port 112 in a stacked state. An alternate long and short dash line with an arrow indicates a part of the conveyance path of the paper 9.

  The image forming apparatus 120 employs a recording method such as a known electrophotographic method or electrostatic recording method. Specifically, an electrostatic latent image based on input image information input from the outside of the apparatus is formed on an image holding member such as a photosensitive member charged by a charging device by the latent image forming device, and then the electrostatic latent image is developed by the developing device. A toner image is formed by developing with the developer supplied from the toner, and then the toner image is directly transferred to one side of the required paper 9 supplied through the paper feed path PR1 by the transfer device or intermediate The transfer material is relayed and transferred. The image forming device 120 is a single color image forming device that forms a single color toner image composed of one type of toner, and a multicolor image forming device that forms a multicolor toner image composed of a plurality of types (colors) of toner. Any of the image devices may be used.

  The paper feed path PR1 is installed in a predetermined number of guide members 141 that form a transport path for the paper 9 in a process from a paper feed device (not shown) to the image forming device 120, and a predetermined position in the transport path. A pair of transport rolls 142. Of the transport rolls 142, the transport roll 142 a installed at a position immediately before the image forming device 120 operates to temporarily stop the leading end portion of the paper 9 being transported and then send it to the image forming device 120 at a predetermined timing. .

  The fixing device 130 includes a heating rotator 131 that is heated to a predetermined temperature by a heating source 132 and rotationally driven, and a pressure rotator 133 that rotates in contact with the heating roll 131 at a predetermined pressure. It is. The heating rotator 131 is rotationally driven at a predetermined speed by a rotation driving device (not shown). In FIG. 1, reference numeral 135 denotes a heat-insulating housing that covers the periphery of the heating rotator 131 and the pressure rotator 133, reference numeral 136 denotes an introduction-side guide plate that can guide the sheet 9 to be fixed at the time of introduction, and 137 denotes fixing. A discharge-side guide plate capable of guiding the subsequent sheet 9 during discharge is shown.

  In the fixing device 130, the sheet 9 to which the toner image is transferred and sent out by the image forming device 120 is guided by the introduction-side guide plate 136 and is brought into contact with the heating rotator 131 and the pressure rotator 133 (fixing nip portion). By being introduced and heated and pressurized when passing through the contact portion, the toner of the toner image is melted and fixed on the paper 9. The sheet 9 after the fixing process is guided to the discharge side guide plate 137 and sent out of the casing 135.

  The discharge transport device 2 constitutes a part of the paper discharge path PR2. As shown in FIGS. 1 to 4, the discharge conveyance device 2 in this embodiment is a pair of paper 9 that is finally fed out from the discharge port 112 and is fed from the fixing device 130 and conveyed via the paper discharge path PR <b> 2. Discharge rolls 21 and 22 and a rotation drive device 23 for rotating the discharge roll 21 are provided. The rotation drive device 23 is composed of an electric motor 23a, a rotation transmission gear 23b, and the like that can be rotated in the forward and reverse directions, and the power of the electric motor 23a is transmitted through a predetermined number of rotation transmission gears 23b. By transmitting to the drive shaft 21b of the discharge roll 21, the discharge roll 21 fixed to the drive shaft 21b is rotated in a predetermined direction and at a predetermined speed. The discharge roll 22 rotates following the rotation of the discharge roll 21 that is driven to rotate at a predetermined pressure.

  2 to 4, reference numeral 20 denotes a support frame in the discharging and conveying apparatus 2, reference numeral 25 denotes a charge eliminating member for discharging the paper 9 when discharged, and reference numeral 26 denotes a sheet 9 that can be accommodated in the discharge accommodating portion 113. Spindle-shaped corrugation rolls, a reference numeral 27 is a discharge assisting tool, and reference numerals 28 and 29 are upper and lower guide surface portions for paper introduction distributed in an area substantially corresponding to the maximum width of the paper 9 to be conveyed. The discharge assisting tool 27 is a member that can swing with the support shaft 27a as a fulcrum, and is normally suspended (when the sheet is not discharged). However, when the sheet 9 is discharged, After being pushed up, it moves so as to finally hang down due to its own weight, and thereby the rear end side of the sheet 9 is pressed down so as to be dropped and reliably accommodated in the discharge accommodating portion 113. .

  The discharge path PR2 is a discharge port 121 (discharge roll) that is disposed at a position obliquely above the fixing device 130 from the position on the paper discharge side of the fixing device 130 (in this example, an upper position shifted to the heating rotator 131 side). 21, 22), and a plurality of guide members 143 that form a conveyance path for the sheet 9. The discharge path PR2 is a paper path that curves so as to swell toward a direction obliquely upward to the left in FIG. 1 (a direction on the left side of the paper conveyance path shown by a one-dot chain line in FIG. 1). As the guide member 143, an upper guide member having an inclined guide surface that gradually rises toward the discharge rolls 21 and 22 at a position above the fixing device 130 is installed. The guide member 143 also functions as a guide member for the reverse conveyance path PR3 described later. Further, the guide member 143 includes the upper and lower guide surface portions 28 and 29 and the paper transport member 1 in the discharge transport device 2. Further, a switching guide member (4) of the reverse conveyance path PR3 described later also functions as a part of the guide member 143.

  In this embodiment, a warp correction roll 5 that corrects the warpage state (so-called curl) of the paper 9 is installed at a position on the paper discharge side of the fixing device 130 that is the starting side of the discharge path PR2. As shown in FIG. 5, the warp correction roll 5 is composed of a pair of rolls 51 and 52 that rotate in contact with each other, and one of the rolls is rotationally driven at a predetermined speed by a rotation driving device (not shown). It becomes the drive roll 51, and when the other roll comes into contact with the drive roll 51, the elastic roll 52 is elastically deformed greatly in a state where the elastic outer peripheral portion is wound around the roll peripheral surface of the drive roll 51. The drive roll 51 in the warp correction roll 5 rotates at the same speed as the heating rotator 131 of the fixing device 130. The elastic roll 52 prevents the paper 9 discharged from the fixing device 130 (front and rear end portions or the whole in the feeding direction) from being bent in a state where the fixing image surface on which the toner image to be fixed exists is inside. From this point of view, it is arranged on the side of the fixed image surface (in other words, the heating rotator 131 of the fixing device).

  The sheet guide member 1 is disposed between the warp correction roll 5 and the discharge roll 21 (22) of the discharge conveyance device 2 in the discharge path PR2, strictly speaking, the paper guide lower guide portion 29 of the warp correction roll 5 and the discharge conveyance device 2. It is installed between. The sheet guide member 1 of this embodiment is integrally installed as a part of the discharge conveyance device 2 and is the most advanced in the feed direction of the sheet 9 discharged upstream of the sheet introduction lower guide portion 29 in the sheet discharge direction. The support part 12 has substantially the same length, and a plurality of conveyance guide parts 14 formed by being divided with a predetermined interval in the longitudinal direction of the support part 12. The paper guide member 1 is attached in a state where the support portion 12 is joined to the paper guide lower guide portion 29 of the discharge conveyance device 2 (FIG. 4).

  As shown in FIGS. 1 and 5, the conveyance guide portion 14 in the sheet guide member 1 has a portion facing the discharge path PR <b> 2 in a direction in which the conveyance path (path) of the discharge path PR <b> 2 curves (left oblique in the figure). It is formed in a shape recessed in the opposite direction (upward direction in the figure). In this embodiment, the paper 9 is formed in a shape curved in a direction opposite to the direction in which the paper 9 is curved.

  The reverse retransmission path PR3 branches at a position before the discharge rolls 21 and 22 of the discharge path PR2, passes through the upper position of the fixing device 130 from the branch point, and reaches the merge point with the sheet feed path PR1. It is composed of a plurality of guide members 145 that form a conveyance path for the sheet 9, and a pair of conveyance rolls 146 to 148 installed in a predetermined number at predetermined positions in the conveyance path. Further, at the branching point of the reverse retransmission path PR3 with the discharge path PR2, the rear end portion 9b of the sheet 9 in the feeding direction of the paper 9 being discharged by the discharge rolls 21 and 22 of the discharge conveyance device 2 is reverse to the discharge roll 21. A switching guide member 4 is provided for switching and conveying the sheet so that it is fed to the paper path side of the reverse retransmission path PR3 by rotation.

  As shown in FIG. 5, the switching guide member 4 in this embodiment swings in the directions of arrows C and D with the support shaft 41 as a fulcrum at the paper discharge side position of the warp correction roll 5 (upper position in FIG. 5). It is a member of the taper form which can do. 1 and 5, the switching guide member 4 is formed as a lower surface guiding portion 42 having a slightly curved shape so that its lower surface swells obliquely upward to the left, and its upper surface is on the upper side. The upper surface guiding portion 43 has a curved shape that swells up. Further, the switching guide member 4 is in a lower position where the tapered leading end portion 4a enters the gap between the conveyance guide portions 14 arranged in a plurality of divided portions of the paper guide member 1 in normal times (when the sheet is not conveyed). On the other hand, when the sheet 9 is discharged and conveyed, the lower guide part 42 is pushed by the leading end of the sheet 9 and is swung in the direction of arrow D to be lifted. (A state indicated by a two-dot chain line in FIG. 5).

  Next, the operation of the image forming apparatus 100 will be described.

  When an image is formed, a toner image based on the input image information is formed in the image forming device 120 as described above, and the toner image is transferred to one side of the paper 9 sent to the image forming device 120 through the paper feed path PR1. The Subsequently, the sheet 9 on which the toner image is transferred by the image forming device 120 is sent out from the image forming device 120 and then sent to the fixing device 130, and the toner image is rotated as described above and the heating rotator 131 and the heating member 131. When passing through the contact portion of the pressure rotator 133, it is heated and pressurized and fixed to the paper 9.

  After the fixing, the sheet 9 is sent out from the fixing device 130 as shown in FIG. 6, and first passes through the warp correction roll 5 that is installed on the starting point side of the discharge path PR2 and rotationally driven. Thereafter, as shown in FIGS. 6 and 7, the sheet 9 is maintained in a state in which the switching guide member 4 is swung up and pushed up, through the discharge path PR2, and in the arrow direction (counterclockwise in the drawing). It is sent to the discharge roll 21 (22) rotating in the direction of rotation) and finally sent out from the discharge port 112 by the discharge roll 21 (22).

  At this time, the leading end 9a of the sheet 9 sent out from the warp correction roll 5 abuts against the lower surface guiding portion 42 of the switching guide member 4, and the direction of the arrow D in the direction of the switching shaft 4 with the support shaft 41 as a fulcrum (FIG. 5). Can be swung. As a result, the leading end portion 4a of the switching guide member 4 is lifted so as to face obliquely upward to the right, and is displaced to a position away from the conveyance guide portion 14 of the paper guide member 1. As a result, the lower surface guidance of the switching guide member 4 is performed. A sheet path as the discharge path PR2 is formed between the section 42 and the conveyance guide section 14 of the sheet guide member 4 (a state indicated by a two-dot chain line in FIG. 5 or a state illustrated in FIG. 6).

  When the sheet 9 passes between the switching guide member 4 and the sheet guide member 1 that are lifted so as to be directed obliquely upward to the right, the sheet 9 is conveyed in a curved state in the upward direction. At this time, the leading end portion and the fixed image surface side of the sheet 9 are conveyed in a state of being spaced from the conveyance guide portion 14 of the sheet guide member 1 installed inside the curved discharge path PR2. There is no contact with the guide portion 14 or a momentary contact (FIGS. 6 and 7). For this reason, the leading end portion or the fixed image surface side of the sheet 9 comes into contact with the conveyance guide unit 14 of the sheet guiding member 1, and the sheet 9 becomes dirty or a part of the fixed image is disturbed. Thus, the occurrence of problems such as the toner adhering to the conveyance guide unit 14 to contaminate the conveyance guide unit 14 is eliminated or reduced.

  Then, the sheet 9 sent out from the discharge port 112 by the discharge rolls 21 and 22 starts to be accommodated with its leading end 9 a landing on the sheet discharge accommodating portion 113. When the rear end portion 9b of the sheet 9 in the feeding direction passes through the switching guide member 4, the switching guide member 4 swings in the direction of arrow C (FIG. 5) with the support shaft 41 as a fulcrum, and the leading end 4a is guided to the sheet. It will be in the state (state shown as the continuous line of Drawing 5) which entered into the crevice between conveyance guide parts 14 of member 1.

  The paper rear end 9b after passing through the switching guide member 4 is pushed by the switching guide member 4 swinging in the direction of arrow C so as to approach the conveyance guide portion 14 of the paper guide member 1, but the paper guide member 1 is not touching or touching momentarily. Even if the paper rear end 9b is warped toward the fixed image surface, the fixed image surface at the rear end 9b is obliquely downward to the right of the paper guide member 1, as shown in FIG. There is no contact with the curved conveyance guide section 14.

  Further, as shown in FIG. 9A, even when the sheet 9 is curved and warped so that the fixed image surface 90 side is inward, the driving roll 51 and the elastic roll 52 of the warp correction roll 5 are provided. Is held in a state of being temporarily pressed along the peripheral surface shape of the drive roll 51, as shown in FIG. 5B, the direction opposite to the fixed image surface 90 side. It is discharged in a state of being temporarily warped. Even when the sheet 9 warped in such a direction passes through the sheet guide member 1, the sheet guide member 1 hardly comes into contact with the conveyance guide unit 14 curved downward.

  Further, in the discharge conveyance device 2, the paper feed speed V 1 of the discharge roll 21 is set to be higher than the paper feed speed V 2 of the warp correction roll 5 (drive roll 51) that first exists on the upstream side of the discharge path PR in the conveyance direction of the discharge path PR 2. Is set to a fast speed (V1> V2). In this embodiment, the paper feed speed V1 of the discharge roll 21 is set to a speed that is, for example, 2.5% faster than the paper feed speed V2 of the warp correction roll (this is the same as the feed speed of the heating rotator 131 of the fixing device).

  For this reason, the portion of the paper 9 that is being transported through the discharge path PR2 that is being transported while being sandwiched between the discharge roll 21 (22) and the warp correction roll 5 (51, 52) is the discharge roll 21. It is pulled to the (22) side, and is conveyed in a state along a substantially straight path connecting the discharge roll 21 (22) and the warp correction roll 5 (51, 52). This also prevents the portion of the sheet 9 between the rolls from coming into contact with the conveyance guide portion 14 that curves downward on the sheet guide member 1.

  When images are formed on both the front and back sides of the paper 9, the following operation is performed.

  In this case, first, after the image is formed on one side (after fixing), the sheet 9 is conveyed by the discharge roll 21 (22) of the discharge conveying device 2, and the rear end portion 9b in the feed direction moves the switching guide member 4 over. At the time after passing through and before passing through the discharge roll 21 (22), the discharge roll 21 is switched to the direction opposite to the discharge direction (clockwise direction in the figure) as shown in FIG. 10 ( Reverse) Start to rotate. At the same time, the transport rolls 146 to 148 in the reverse transport path PR3 (on the drive roll side of the pair of rolls) start to rotate in the paper transport direction (clockwise direction in the drawing). At this time, the paper feed speed V3 of each of the transport rolls 146 to 148 in the reverse transport path PR3 is set to the same speed as the paper feed speed V1 of the discharge roll 21 that rotates in the reverse direction.

  At this time, the sheet 9 starts to be conveyed with the trailing end 9b leading, due to the conveying force of the reversely rotating discharge roll 21 (22), and is normally guided to the upper surface guiding part 43 of the switching guiding member 4 ( The state shown by the sheet rear end portion 9b shown by a two-dot chain line in FIG. 10) is conveyed toward the reverse conveying path PR3.

  At this time, even when the rear end 9b of the sheet is warped with the fixed image surface side inward (downward), the sheet rear end 9b is swung in the arrow C direction and is in the lower position. The upper surface guide portion 42 of the switching guide member 4 is continuous with the conveyance guide portion 14 of the paper guide member 1 obliquely intersecting (for example, intersecting at an obtuse angle of 130 ° or more), in other words, curved downward and continuous. The paper guide section is configured. For this reason, the sheet rear end portion 9b along the lower side starts to be guided in a state in which the sheet rear end portion 9b is in contact with the conveyance guide portion 14 of the sheet guide member 1 and then smoothly moves to the upper surface guide portion 42 of the switching guide member 4. To be guided to. As a result, the sheet rear end portion 9b is guided to the upper surface guide portion 42 of the switching guide member 4 and is stably fed to the reverse conveyance path PR3.

  As shown in FIG. 11, the rear end portion 9b of the sheet 9 guided to the upper surface guide portion 42 of the switching guide member 4 is first disposed on the upstream side in the transport direction of the reverse transport path PR3 and is driven to rotate. Are held on the reverse conveyance path PR3 by the conveyance force of the conveyance roll 146. At this time, the front end portion 9a when the sheet 9 is discharged is conveyed by the reversely rotating discharge rolls 21 and 22 so as to be pulled back to the discharge path PR2 from the discharge storage section 113, and then the reverse conveyance path PR3. Is sent to. Thus, the sheet 9 when being conveyed so as to be fed into the reverse conveying path PR3 does not come into contact with the conveyance guide portion 14 of the sheet guide member 1 on the fixed image surface 90 side.

  Then, the sheet 9 sent to the reverse conveyance path PR3 is conveyed one after another by the conveyance force of each of the conveyance rolls 146 to 148, and is retransmitted in a state where the front and back surfaces are reversed to the paper supply path PR1. The paper 9 retransmitted to the paper feed path PR1 is transferred to the fixing device 130 after the toner image is transferred to the opposite side by the image forming device 120, and subjected to fixing processing. Further, the sheet 9 fixed by the fixing device 130 is transported through the discharge path PR2 in the same state as described above, and finally sent out from the discharge port 112 to the discharge storage unit 113 for storage.

[Modification]
In the above-described embodiment, the conveyance guide portion 14 of the paper guide member 1 is formed in a curved state, but may be formed in a concave shape that is bent in the same direction. However, from the viewpoint of realizing stable guidance of the paper, it is preferable that the conveyance guide unit 14 has a curved shape.

  In the above-described embodiment, the configuration example in which the paper guide member 1 is integrally installed as a part of the discharge conveyance device 2 has been described. However, the paper guide member 1 is separate from the discharge conveyance device 2. You may comprise so that it may install as. In addition, the paper guide member 1 can be disposed inside the paper path that is curved between the fixing device 130 and the warp correction roll 5 (as a discharge guide member).

  Furthermore, the paper guide member 1 is not limited to being installed in the discharge path PR2, but can be installed in other curved paper transport paths. For example, in the guide member 145 that forms a curved paper path between the transport roll 146 and the transport roll 147 in the reverse retransmission path PR3 in FIG. 1, the paper is placed on the inner side (right side in the drawing) of the curved direction. The guide member 1 can be installed.

  In addition, the paper guide member 1 and the discharge conveyance device 2 using the same illustrated in the above embodiment are not limited to the case of being applied to the image forming apparatus 100, and other devices having a paper conveyance path that curves in a certain direction. It is possible to apply to. Other devices include, for example, a paper feeding device (curved paper conveyance path) that supplies a large amount of paper and supplies the paper to the image forming apparatus, and paper on which an image is formed by the image forming apparatus. And a post-processing device that performs post-processing such as aligning and binding (curved paper conveyance path).

  Further, the discharge conveyance device 2 and the image forming apparatus 100 exemplified in the above embodiment may be omitted without installing the warp correction roll 5. In the case where the warp correction roll 5 is not installed, the transport driving means that first exists on both sides in the transport direction in the discharge path PR2 is the heating rotator 133 (and the pressure rotator) of the fixing device 130. In addition, instead of the warp correction roll, a known warp correction means having another configuration (form) may be applied.

FIG. 3 is an explanatory diagram illustrating a main part of a sheet guide member, a discharge conveyance device, and an image forming apparatus using the same according to an embodiment. FIG. 2 is a perspective view (when viewed from the paper introduction side) illustrating the paper guide member and the discharge conveyance device in FIG. 1. FIG. 2 is a perspective view (when viewed from the paper discharge side) illustrating the paper guide member and the discharge conveyance device in FIG. 1. It is a partial cross section figure which follows the QQ line of FIG. It is explanatory drawing which expands and shows the structure of a paper guide member, a switching guidance member, and a curvature correction roll. FIG. 6 is an explanatory diagram illustrating a state when a sheet after fixing is conveyed through a discharge path (an initial stage of being fed). FIG. 10 is an explanatory diagram illustrating a state when a sheet after fixing is conveyed through a discharge path (a middle stage in which a sheet front end is sent out from a discharge port). FIG. 10 is an explanatory diagram illustrating a state when a sheet after fixing is conveyed through a discharge path (the final stage after the sheet rear end portion has passed through a switching guide member). It is explanatory drawing which shows the state of the paper before and after passing through the curvature correction roll. FIG. 6 is an explanatory diagram illustrating a state when a sheet is conveyed on a reverse conveyance path (an initial stage of being fed). FIG. 10 is an explanatory diagram illustrating a state when a sheet is conveyed on a reverse conveyance path (an intermediate stage when the sheet is held by the first conveyance roll in the reverse conveyance path).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Paper guide member, 2 ... Discharge conveyance apparatus, 4 ... Switching guidance member, 5 ... Warpage correction roll (warpage correction means, the conveyance drive means which exists initially), 9 ... Paper, 14 ... Conveyance guide part (conveyance guide part) ) 21, 22... Discharge roll, 43... Upper surface guide part (switching guide part), 120... Image forming device, 130... Fixing device, PR2... Discharge path (paper conveyance path, paper discharge path on a curved path), PR3 ... Reverse retransmission path (paper transport path having a curved path).

Claims (7)

Installed inside the curving direction of the paper transport path for transporting the paper along the path curving in a certain direction,
A paper guide member characterized in that a conveyance guide portion facing the paper conveyance path is formed in a shape recessed in a direction opposite to the curving direction. Inside the curving direction of the paper discharge path for transporting the paper fed from the fixing device for fixing the unfixed image to the paper to the discharge port along the path curved in a certain direction,
A discharge conveying apparatus comprising: a sheet guide member in which a conveyance guide portion facing the sheet discharge path is formed in a shape recessed in a direction opposite to the curving direction. A discharge roll that rotates and feeds the paper from the discharge port;
3. The discharge transport apparatus according to claim 2, wherein the paper feed speed of the discharge roll is set to be higher than the paper feed speed of the transport driving means that is first present upstream of the discharge roll in the transport direction of the paper discharge path. The discharge roll has a function to reversely rotate and switch the paper feed direction,
The paper guide member is installed at a position on the paper introduction side of the discharge roll,
The switching guide member for switching and guiding the transport destination of the paper transported by the reverse rotation of the discharge roll is displaced so that the switching guide portion obliquely intersects the transport guide portion of the paper guide member and is continuous. The discharge conveyance device according to claim 2 or 3 installed in. A warp correcting means for allowing a sheet fed from the fixing device between the fixing device and the discharge port to pass in a state curved in a direction opposite to a direction in which the sheet conveying path is curved;
The discharge conveyance device according to any one of claims 2 to 4, wherein the sheet guide member is installed between the warp correction means and the discharge port.   The paper guide path according to claim 1, further comprising a paper transport path that transports the paper along a path that curves in a certain direction, and the paper guide member according to claim 1 is disposed inside the curved direction of the paper transport path. An image forming apparatus.   An image forming device that forms an unfixed image on a sheet, a fixing device that fixes an unfixed image formed by the image forming device on the sheet, and the discharge conveyance device according to claim 2. An image forming apparatus.

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