Paper guiding device and image forming apparatus

Abstract

The present invention provides a paper guide device that can suppress the static electricity causing the transported paper to stick to an electrostatically charged auxiliary member attached to the guide surface of the transport guide section, compared to a case where the auxiliary member does not have multiple narrow sections that narrow in the direction of paper transport. [Solution] The paper guiding device 6A includes a transport guide section 61 having a guide surface 62a that guides the transported paper 19 through to the destination, and an electrostatic auxiliary member 65 attached to the guide surface 62a to assist in the guidance. The auxiliary member 65 is arranged in a width direction D that intersects the transport direction C of the paper 19 and has a plurality of narrowing sections 70 that have a shape in which the width narrows toward the transport direction C.

Description

Technical Field

[0001] The present invention relates to a paper guiding device and an image forming apparatus.

Background Art

[0002] The following Patent Document 1 describes a guiding portion for guiding a recording material and a recording material guiding device having a thin plate material provided in the guiding portion. The above guiding portion is a portion provided at an opposing position where a first rotating body and a second rotating body face each other to guide a recording material. The above thin plate material is a plate-like member that is more easily elastically deformed than the guiding portion, and is a plate material that guides the conveyed recording material along the plate surface. Further, the above thin plate material is a plate material having a thickness on the downstream side in the conveying direction that is thinner than that on the upstream side. Further, Patent Document 1 describes a guiding portion for guiding a recording material and a recording material guiding device having a plate material provided in the guiding portion. The above plate material is a plate material that extends toward the downstream side in the conveying direction toward the center in the width direction intersecting the conveying direction of the recording material and in which slits are formed.

[0003] The following Patent Document 2 describes an image forming apparatus provided with a guide member for guiding to a transfer region. The above guide member forms a contact portion that contacts a transfer material with a conductive material, and is a member for installing the contact portion. The above transfer region is a region between a toner image carrier and a transfer means. Further, the above guide member is also a member in which aluminum is vapor-deposited on a Mylar surface. Furthermore, the above guide member is also a carbon-added Mylar.

[0004] The following Patent Document 3 describes an image forming apparatus provided with a conveying means, a first guiding portion, a second guiding portion, and the like. The above conveying means is a means for conveying a transfer medium toward an image carrier. The first guide portion is a member that guides the transfer medium toward the image carrier. The first guide portion has a flexible first guide surface, its first base end is fixed in position, and the first tip of the first base end extends toward the image carrier. The second guide section described above is a means for transporting the transfer medium toward the image carrier. The second guide portion has a flexible first guide surface, its second base end is fixed in position, and the first tip of the first base end is extended toward the upstream side in the conveying direction and faces the first tip. Furthermore, Patent Document 3 describes that at least one of the first guide portion and the second guide portion is formed of a film material. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-54649 (Claim 19, Figures 2-6, 2-10) [Patent Document 2] Japanese Patent Publication No. 2000-172083 (Claim 1, Figure 1) [Patent Document 3] Japanese Patent Publication No. 2006-208840 (Claim 27, 28, Figure 2-7) [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention provides a paper guiding device and an image forming apparatus equipped therewith, which can suppress the static electricity adhesion of the transported paper to a charged auxiliary member attached to the guide surface of the transport guide section that assists in guiding the paper, compared to a case where the auxiliary member does not have multiple narrow sections that narrow in the direction of paper transport. [Means for solving the problem]

[0007] A first aspect of the present invention is: A transport guide unit having a guide surface that guides the transported paper through and toward the destination, A chargeable auxiliary member attached to the guide surface to assist in the guidance, Equipped with, The auxiliary member is a paper guide device that is arranged in a width direction intersecting the paper transport direction and has multiple narrow sections whose width narrows toward the transport direction.

[0008] A second aspect of the present invention is the paper guiding device of the first aspect described above, The aforementioned multiple narrow sections are a paper guide device in which the downstream ends in the transport direction are aligned with each other in the width direction.

[0009] A third aspect of the present invention is the paper guiding device of the first aspect described above, The paper guide device has a shape in which some of the narrow sections of the plurality of narrow sections have a diagonal side of a straight line that intersects with the planned passing position of at least one end of the left and right ends during paper transport.

[0010] A fourth aspect of the present invention is the paper guiding device of the third aspect described above, The narrow section having the aforementioned slanted side is a paper guide device in which the slanted side is inclined toward the center in the width direction with respect to the transport direction.

[0011] A fifth aspect of the present invention is the paper guiding device of the third aspect described above, The narrow section having the aforementioned slanted side is a paper guide device having a parallel side on the opposite side of the slanted side that is parallel to the transport direction.

[0012] A sixth aspect of the present invention is the paper guiding device of the third aspect described above, The remaining narrow section, apart from the aforementioned narrow section with a hypotenuse, is a paper guide device whose planar shape is an isosceles triangle with the width direction as its base.

[0013] A seventh aspect of the present invention is the paper guiding device of the third aspect described above, The narrow portion having the hypotenuse is a paper guide device arranged such that the hypotenuse exists in a line-symmetric relationship in the width direction.

[0014] The eighth aspect of the present invention is the paper guiding device according to the first aspect, wherein the auxiliary member includes a first auxiliary member attached to the guiding surface and a second auxiliary member having the narrow portion attached to the side opposite to the guiding surface of the first auxiliary member.

[0015] The ninth aspect of the present invention is the paper guiding device according to the eighth aspect, wherein a part of the first auxiliary member is attached in a state of protruding from an end portion on the downstream side in the conveying direction of the guiding surface, the second auxiliary member is attached in a state where the downstream end in the conveying direction of the narrow portion is shifted to the upstream side in the conveying direction from the end portion on the downstream side in the conveying direction of the first auxiliary member.

[0016] The tenth aspect of the present invention is the paper guiding device according to the ninth aspect, wherein the second auxiliary member is a member that is less likely to be charged than the first auxiliary member.

[0017] The eleventh aspect of the present invention is the paper guiding device according to the first aspect, wherein the auxiliary member is a film or sheet made of synthetic resin.

[0018] The twelfth aspect of the present invention is the paper guiding device according to the first aspect, wherein assuming that the narrow portion is a remaining portion after cutting off a part of the original member having a quadrangular planar shape, the planar area of the narrow portion is an area that is half or less of the planar area of the original member.

[0019] The thirteenth aspect of the present invention is the paper guiding device according to the first aspect, wherein the conveyance destination is a position where an image is formed on the paper.

[0020] A fourteenth aspect of the present invention is the paper guiding device of the first aspect described above, The destination of the transport is a paper guide device, which is the position where the paper will be folded and where it will be folded.

[0021] A fifteenth aspect of the present invention is an image forming apparatus equipped with a paper guiding device according to any of the first to fourteenth aspects described above. [Effects of the Invention]

[0022] According to the paper guiding device of the first embodiment described above, the tendency for the transported paper to stick due to static electricity to the electrostatic auxiliary member attached to the guide surface of the transport guide section to assist in guiding the paper can be suppressed compared to the case where the auxiliary member does not have multiple narrow sections that narrow in the direction of paper transport.

[0023] According to the paper guide device of the second embodiment described above, the paper is more easily transported stably compared to the case where the downstream ends of the multiple narrow sections are not aligned in the width direction.

[0024] According to the third embodiment of the paper guiding device described above, the risk of the paper being transported at an angle is reduced compared to a device without a narrow section having a slanted edge.

[0025] According to the paper guiding device of the fourth embodiment described above, the risk of the paper being transported at an angle is reduced compared to the case where the slanted edge of the narrow portion is inclined away from the center in the width direction with respect to the transport direction.

[0026] According to the fifth embodiment of the paper guiding device described above, the risk of the paper being transported at an angle is reduced compared to the case where the narrow section having a slanted side does not have a parallel side on the opposite side of the slanted side that is parallel to the transport direction.

[0027] According to the paper guide device of the sixth embodiment described above, the paper is more easily transported stably compared to the case where the remaining narrow section other than the narrow section with the inclined section has a planar shape other than an isosceles triangle (excluding an equilateral triangle).

[0028] According to the paper guiding device of the seventh embodiment described above, the paper is more easily transported stably without becoming skewed compared to the case where the narrow section having a hypotenuse is arranged so that the hypotenuse does not exist in a line-symmetric relationship in the width direction.

[0029] According to the paper guiding device of the eighth embodiment described above, even if the first auxiliary member is a member that is easily charged, it is possible to suppress the paper from sticking to the first auxiliary member due to static electricity.

[0030] According to the paper guiding device of the ninth embodiment described above, compared to the case where a part of the first auxiliary member is not mounted in a protruding state and the downstream end of the second auxiliary member is not mounted in a misaligned state, the paper is less likely to stick to the first auxiliary member due to static electricity, and the paper can be guided stably.

[0031] According to the tenth embodiment of the paper guiding device described above, compared to the case where the second auxiliary member is more prone to static electricity than or to the same extent as the first auxiliary member, the paper is less likely to stick to the first auxiliary member due to static electricity.

[0032] According to the paper guide device of the 11th embodiment described above, compared to the case where the auxiliary member is not a film or sheet made of synthetic resin, the paper can be transported stably by suppressing static electricity-induced sticking of the paper with an auxiliary member that has a simpler structure.

[0033] According to the paper guiding device of the 12th embodiment described above, compared to the case where the flat area of ​​the narrow portion is larger than half the flat area of ​​the original member, it is easier to suppress the paper from sticking to the auxiliary member due to static electricity.

[0034] According to the paper guiding device of the 13th embodiment described above, the paper can be guided toward the position where the image is formed while suppressing it from sticking to the auxiliary member due to static electricity.

[0035] According to the paper guiding device of the 14th embodiment described above, the paper can be guided toward the folding position and the position beyond the folding point while preventing it from sticking to the auxiliary member due to static electricity.

[0036] According to the image forming apparatus of the 15th embodiment described above, in the paper guiding device, the tendency for the transported paper to stick due to static electricity to an electrostatic auxiliary member attached to the guide surface of the transport guide section to assist in guiding the paper can be suppressed compared to the case where the auxiliary member does not have multiple narrow sections that narrow in the direction of paper transport. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic diagram of an image forming apparatus equipped with a paper guiding device according to Embodiment 1. [Figure 2] This is a schematic diagram of the paper guiding device and its surrounding area according to Embodiment 1. [Figure 3] Figure 2 is an enlarged schematic diagram of the paper guiding device, etc. [Figure 4] (A) is a schematic plan view of the first transport guide section and the auxiliary member having a narrow section, and (B) is a schematic cross-sectional view along the QQ line of (A). [Figure 5] This is an enlarged plan view of the narrow section. [Figure 6] This is an explanatory diagram showing the configuration of the narrow section of Figure 5. [Figure 7] (A) is a front view diagram illustrating the operation of the paper guide device, and (B) is a side view diagram illustrating the operation of the paper guide device. [Figure 8] This is a graph showing the results of the evaluation test. [Figure 9] This is a graph showing the results of a comparative test. [Figure 10] This is a schematic diagram of a reversing transport device equipped with a paper guiding device according to Embodiment 2. [Figure 11] This is a schematic diagram of the front view of the paper guide device and its surrounding area according to Embodiment 2. [Figure 12] Figure 11 is a schematic diagram of the paper guide device and its surrounding area from the side. [Figure 13] (A) is a front-view explanatory diagram showing the operation of the reversing transport device and the paper guide device, and (B) is a front-view explanatory diagram showing the operation following (A). [Modes for carrying out the invention]

[0038] The following describes embodiments for carrying out the present invention.

[0039] Embodiment 1. Figure 1 shows an image forming apparatus 10 equipped with a paper guiding device 6A according to Embodiment 1. Figure 2 shows a paper guiding device 6A according to Embodiment 1.

[0040] In this specification and the drawings, substantially identical components are denoted by the same reference numerals. Furthermore, redundant descriptions of these identical components are omitted in this specification. In Figure 1, etc., the arrow +X indicates the right direction when viewed from the front of the image forming apparatus 10, and the arrow -X indicates the left direction. Also, the arrow +Y indicates the upward direction of the image forming apparatus 10, and the arrow -Y indicates the downward direction. Furthermore, the symbol +Z indicates the depth direction when viewed from the front of the image forming apparatus 10, and the symbol -Z indicates the forward direction. In addition, the symbol with a "×" inside a "○" in Figure 1, etc., indicates the direction from the front to the back of the drawing. The symbol with a "·" inside a "○" indicates the direction from the back to the front of the drawing.

[0041] (Image forming apparatus) The image forming apparatus 10 is an apparatus for forming a predetermined image on a sheet of paper 19. An image is a representational element of various information, including visible text, figures, tables, and still images, on a sheet of paper. As shown in Figure 1, the image forming apparatus 10 has the image forming apparatus 20, paper supply device 40, etc., arranged inside the housing 11. Additionally, the image forming apparatus 10 has a paper guiding device 6A located inside the housing 11.

[0042] Of these, the housing 11 is a box-shaped structure having a predetermined external shape and internal space. The enclosure 11 is composed of, for example, a frame, plates, exterior materials, etc. The housing 11 is provided with a paper output and storage section 12 at its top for ejecting and storing the paper 19 on which the image has been formed. The housing 11 is also provided with a paper output port 13 near the paper output and storage section 12 for ejecting the paper 19.

[0043] The image forming apparatus 20 in Embodiment 1 is configured as an apparatus that employs an image forming method such as electrophotography. The image forming apparatus 20 comprises four imaging units 21A, 21B, 21C, and 21D, an intermediate transfer unit 30, and a fixing unit 50.

[0044] The image-forming units 21A, 21B, 21C, and 21D are units that create unapplied toner images using developers of predetermined colors (A, B, C, D). Examples of predetermined colors (A, B, C, D) include yellow, magenta, cyan, and black.

[0045] Each of the image-forming units 21A, 21B, 21C, and 21D has a photosensitive drum 22 that is driven to rotate in the direction indicated by arrow A. Around each photosensitive drum 22, a charging device 23, an exposure device 24, a developing device 25, a drum cleaning device 26, and the like are similarly arranged.

[0046] The charging device 23 is a device that charges the image-forming surface on the outer surface of the photosensitive drum 22 to a predetermined surface potential. The exposure apparatus 24 is a device that forms an electrostatic latent image by irradiating light onto the charged image-forming surface of the photosensitive drum 22. The light to be irradiated is generated in accordance with image information input from outside the image forming apparatus 10. The developing device 25 is a device that develops the electrostatic latent image on the photosensitive drum 22 with a predetermined color developer (toner) to form a toner image.

[0047] In Figure 1, the symbols for the charging device 23, exposure device 24, and drum cleaning device 26 are shown only for the image-making unit 21D. Furthermore, the developing device 25 is labeled 25A, 25B, 25C, and 25D to correspond to the different colors of developer used (A, B, C, D).

[0048] The intermediate transfer unit 30 is a unit that relays the toner images created by the image-forming units 21A, 21B, 21C, and 21D of the image-forming apparatus 20 and transfers them to the paper 19. The intermediate transfer unit 30 includes an intermediate transfer belt 31, a primary transfer device 33, a secondary transfer device 34, a belt cleaning device 36, and the like.

[0049] The intermediate transfer belt 31 is an endless belt capable of holding and transporting the toner image on its outer surface, primarily by electrostatic force. The intermediate transfer belt 31 rotates as it passes over each of the photosensitive drums 22 of the image-forming units 21A, 21B, 21C, and 21D. The intermediate transfer belt 31 is also wrapped around a predetermined number of support rolls 32a, 32b, 32c, and 32d and rotates in the direction indicated by arrow B.

[0050] Of these, support roll 32a is configured, for example, as a drive roll and secondary transfer back roll. Support roll 32b is configured as a belt travel adjustment roll to adjust the travel state of the intermediate transfer belt 31. Support rolls 32c and 32d are configured as surface preparation rolls that form the primary transfer surface on the intermediate transfer belt 31.

[0051] The primary transfer device 33 is a device that transfers each toner image formed on each photosensitive drum 22 to the outer surface of the intermediate transfer belt 31. The secondary transfer device 34 is a device that transfers the toner image, which was primarily transferred to the outer surface of the intermediate transfer belt 31, to one side of the paper 19. In Figure 1, the symbol TP1 indicates the primary transfer position where the primary transfer device 33 faces each photosensitive drum 22 across the intermediate transfer belt 31. The symbol TP2 indicates the secondary transfer position where the secondary transfer device 34 faces the support roll 32a across the intermediate transfer belt 31.

[0052] The paper supply device 40 is a device that receives a predetermined amount of paper 19 and then supplies it to the image forming apparatus 20. The paper supply device 40 includes a container 41 for holding the paper 19, a feeder 43 for feeding the paper 19 one sheet at a time from the container 41, and the like. The paper supply device 40 may also consist of multiple sets of containers 41 and feeders 43.

[0053] The paper 19 is a recording medium that is transported inside the housing 11 and can be used to transfer toner images in the image forming apparatus 20. The paper 19 is mainly a sheet-like material cut to a predetermined size. The paper 19 is not limited to pulp paper. For example, the paper 19 may be coated paper coated with a resin material.

[0054] The fixing unit 50 is a unit that fixes the toner image formed on the paper 19 by the image forming apparatus 20 to the paper 19. The fixing unit 50 is constructed by arranging a heating rotating body 52, a pressurizing rotating body 53, etc., inside the fixing housing 51. The heating rotating body 52 and the pressurizing rotating body 53 are rotating bodies in the form of a roll or a belt. The heating rotating body 52 and the pressurizing rotating body 53 come into contact under pressure and rotate in the direction indicated by the dashed arrow. In the fixing unit 50, the contact area between the heating rotating body 52 and the pressurizing rotating body 53 becomes a fixing nip that passes the paper 19 through for fixing. The fixing nip also serves as the fixing position FP.

[0055] Inside the housing 11, a paper transport path Rt is provided, which is illustrated by a dashed line in Figure 1. The paper transport path Rt has a transport path from the paper supply device 40 through the intermediate transfer unit 30 and the fixing unit 50 to the discharge port 13. The paper transport path Rt is composed of a predetermined number of pairs of transport rolls 45, 46, 47, 48 and transport guide members (not shown). As part of the transport guide members, a transport guide section 61 (see Figure 2, etc.), which will be described later in the paper guide device 6A, is arranged.

[0056] Of these, a pair of transport rolls 46 are adjustment rolls that temporarily stop the paper 19 and then feed it out in time for the secondary transfer operation. The adjustment rolls are also called registration rolls. The pair of transport rolls 46 are configured by making contact between a drive roll 46a and a driven roll 46b.

[0057] A paper guide device 6A is positioned in the paper transport path Rt to guide the paper 19, which has been fed out from a pair of transport rolls 46, to the secondary transfer position TP2. Details of the paper guide device 6A will be described later.

[0058] (Image formation process) Image formation by the image forming apparatus 10 is performed as follows. This explanation assumes that toner images are formed using all of the image-forming units 21A, 21B, 21C, and 21D of the image-forming apparatus 20.

[0059] When the control unit (not shown) of the image forming apparatus 10 receives a command to perform an image forming operation, the image forming apparatus 20, paper supply device 40, etc., are started.

[0060] At this time, in the image forming apparatus 20, each photosensitive drum 22 of the image forming units 21A, 21B, 21C, and 21D begins to rotate in the direction indicated by arrow A. In addition, charging, exposure, development, transfer, and cleaning operations are performed on the rotating photosensitive drums 22.

[0061] At this time, in the image forming apparatus 20, the intermediate transfer belt 31 in the intermediate transfer unit 30 begins to rotate in the direction indicated by arrow B. In the intermediate transfer unit 30, the primary transfer operation, secondary transfer operation, and cleaning operation are performed. Furthermore, at this time, the paper supply device 40 and the paper transport path Rt perform paper feeding operations in accordance with the timing of the secondary transfer operation.

[0062] As a result, in the image forming apparatus 20, after the toner image of the color corresponding to each photosensitive drum 22 is formed, it is first transferred to the intermediate transfer belt 31 and transported to the secondary transfer position TP2. Meanwhile, in the image forming apparatus 20, a predetermined sheet of paper 19 is fed from the paper supply device 40 and supplied to the secondary transfer position TP2 via the paper transport path Rt. At this time, the paper 19 fed out by the pair of transport rolls 46 is transported to the secondary transfer position TP2 via the paper guide device 6A.

[0063] Then, in the image forming apparatus 20, the toner image is secondarily transferred from the intermediate transfer belt 31 to the paper 19 at the secondary transfer position TP2.

[0064] Furthermore, when the image forming apparatus 20 receives a command for image forming, the fixing unit 50 starts up in earnest. At this time, the heating rotating body 52 and the pressurizing rotating body 53 in the fixing unit 50 begin to rotate. Also at this time, the heating rotating body 52 in the fixing unit 50 begins to heat up to a temperature at which fixing is possible. Then, in the fixing unit 50, the fixing operation is performed after the temperature is maintained at a temperature suitable for the fixing operation.

[0065] As a result, in the image forming apparatus 20, the paper 19 on which the toner image has been secondarily transferred is introduced into and passed through the fixing nip of the fixing unit 50. At this time, the toner on the paper 19 is heated and melted under pressure as it passes through the fuser nip, and is fixed to the paper 19.

[0066] Finally, in the image forming apparatus 10, the fixed paper 19 is transported from the fixing unit 50 through the paper transport path Rt to the paper discharge port 13. At this point, the fixed paper 19 is discharged from the discharge port 13 by the discharge roll 48 and stored in the paper discharge storage section 12.

[0067] The above series of operations completes the image formation process, which forms an image composed of predetermined colors (A, B, C, D) on one side of the paper 19.

[0068] (Paper guide device) As shown in Figures 2 and 3, the paper guide device 6A includes at least a transport guide section 61 and an auxiliary member 65. In Embodiment 1, the paper guide device 6A constitutes a part of the paper transport path Rt. Furthermore, this paper guide device 6A is positioned between the pair of transport rolls 46 and the secondary transfer position TP2.

[0069] The transport guide section 61 is a component having a guide surface that guides the transported paper 19 through to the destination. In Embodiment 1, the transport guide section 61 is composed of a first guide member 62, a second guide member 63, and a third guide member 64.

[0070] The first guide member 62 is a plate-like member with a rectangular planar shape and a predetermined thickness. The rectangular planar shape is approximately rectangular, elongated along the width direction D which intersects the transport direction C of the paper 19 (see Figure 4(A)). The first guide member 62 is positioned so as to extend from a position where it has passed the pair of conveyor rolls 46 to a position where it approaches the intermediate transfer belt 31. This approaching position is a position where it faces the portion of the intermediate transfer belt 31 supported by the support roll 32d at a predetermined angle and distance.

[0071] The third guide member 64 is positioned between the pair of transport rolls 46 and the upstream end 62d of the first guide member 62. The upstream end 62d is the upstream end of the first guide member 62 in the transport direction C of the paper 19.

[0072] The second guide member 63 is positioned to face the first guide member 62 and the third guide member 64 with a predetermined distance between them. As a result, the second guide member 63 forms a transport space TA through which the paper 19 passes between the first guide member 62 and the third guide member 64. The transport space TA is a space in which the gap gradually narrows toward the downstream side in the transport direction C of the paper 19.

[0073] Furthermore, the first guide member 62 has a guide surface 62a formed on the side opposite to the intermediate transfer belt 31 that can guide the paper 19. The guide surface 62a is a nearly flat surface, but a bent surface 62b is provided on the upstream side in the paper transport direction C of the paper 19. The bent surface 62b is a plane that bends at a predetermined angle in the direction approaching the second guide member 63.

[0074] Furthermore, guide surfaces 63a and 64a are also formed on the second guide member 63 and the third guide member 64, respectively. The guide surface 63a has a surface shape that curves at a predetermined angle in the direction away from the first guide member 62. The guide surface 64a has a surface shape that is almost continuous with the curved surface 62b of the guide surface 62a. Both guide surfaces 63a and 64a are provided with multiple protrusions that extend linearly and parallel to each other along the paper transport direction C of the paper 19 on a flat surface. These protrusions are also called ribs.

[0075] In this embodiment, the first guide member 62 is made of a metal material. Furthermore, both the second guide member 63 and the third guide member 64 are made of resin material. The second guide member 63 and the third guide member 64 are independent, dedicated components, but they may also be formed as part of other components.

[0076] The auxiliary member 65 is attached to the guide surface 62a of the first guide member 62, which serves as the transport guide section 61, and is a member that assists in guiding the paper 19. Furthermore, the auxiliary member 65 is also a material that can be charged. Chargeability is a physical property that can be charged by external factors. For example, an external factor may be that a charged sheet of paper 19 comes into contact with or approaches the auxiliary member 65 as it passes by.

[0077] Furthermore, the auxiliary member 65 has multiple narrow sections 70, as shown in Figure 4, etc. The narrow portion 70 is a part whose width narrows in the direction C of paper transport. The narrow portion 70 is also a part that lies parallel to the width direction D, which intersects with the paper transport direction C of paper transport. The width of the narrow section 70 is the dimension along the width direction D mentioned above.

[0078] As shown in Figures 3 and 4, the auxiliary member 65 in Embodiment 1 is composed of a first auxiliary member 66 and a second auxiliary member 67.

[0079] The first auxiliary member 66 is an auxiliary member attached to the guide surface 62a of the first guide member 62. In Embodiment 1, the first auxiliary member 66 is a film or sheet made of synthetic resin. Here, the film is, for example, a thin film with a thickness of less than 250 μm. The sheet is, for example, a thin film with a thickness of 250 μm or more. Examples of synthetic resins include polypropylene (PP), polyacetal resin (POM), and polyethylene terephthalate (PET).

[0080] Furthermore, the first auxiliary member 66 in Embodiment 1 is configured as a member of a predetermined thickness with a substantially rectangular planar shape. This first auxiliary member 66 is attached to almost the entire surface of the guide surface 62a, excluding the bent surface 62b, by fastening means such as double-sided tape. The first auxiliary member 66 is attached such that its downstream end 66e protrudes from the downstream end 62e of the first guide member 62. The downstream end 66e of the first auxiliary member 66 is the end that is downstream in the paper transport direction C of the paper 19. The downstream end 66e of the first auxiliary member 66 protrudes to a position that is almost opposite the downstream end 63e of the second guide member 63. Furthermore, the upstream end 66d of this first auxiliary member 66 is positioned to reach the boundary with the bent surface 62b of the guide surface 62a.

[0081] The second auxiliary member 67 is attached to the opposite side of the guide surface 62a of the first auxiliary member 66 and is an auxiliary member having a narrow portion 70. In Embodiment 1, the second auxiliary member 67 is a film or sheet made of synthetic resin, similar to the first auxiliary member 66. Examples of synthetic resins include polypropylene (PP) and polyacetal resin (POM).

[0082] Furthermore, the second auxiliary member 67 in Embodiment 1 is configured as a member of a predetermined thickness consisting of a base portion 672 and a narrow portion 70. The base portion 672, as shown in Figures 4 and 5, is a part with a substantially rectangular planar shape and a predetermined thickness. The base portion 672 is installed and used with its longitudinal direction aligned with the width direction D.

[0083] The narrow section 70 is a portion composed of multiple narrow sections 71, 72, and 73, each having a triangular planar shape. The narrow sections 71, 72, and 73 are arranged to be aligned along one of the longer sides of the base section 672 (see Figure 5, etc.). The narrow sections 71, 72, and 73 are formed to the same thickness as the base section 672.

[0084] The narrow section 71 is a narrow section located in the central region in the width direction D of the area through which the transported paper 19 can pass. Furthermore, the narrow portions 71 are formed in such a way that multiple portions are arranged side by side in the width direction D. In Embodiment 1, five narrow portions 71 are arranged side by side in the width direction D.

[0085] The narrow sections 72 and 73 are narrow sections located at the edges on both sides of the central region in the width direction D of the area through which the transported paper 19 can pass. Furthermore, the narrow portions 72 and 73 are formed in such a way that multiple portions are lined up in the width direction D. In Embodiment 1, six narrow portions 72 and 73 are arranged in the width direction D. The number and position of the narrow sections 72 and 73 are selected mainly to correspond to the type of paper width W being transported 19.

[0086] In the narrow sections 71, 72, and 73, the downstream ends 71e, 72e, and 73e in the paper transport direction C are aligned with each other in the width direction D (see Figure 5). The downstream ends 71e, 72e, and 73e are rounded (chamfered).

[0087] The second auxiliary member 67 is attached to the first auxiliary member 66 in a position offset to the upstream side in the paper transport direction C. Specifically, the downstream ends 71e, 72e, and 73e of the narrow sections 71, 72, and 73 are shifted upstream in the paper transport direction C of the first auxiliary member 66 compared to the downstream end 66e of the first auxiliary member 66.

[0088] Furthermore, the second auxiliary member 67 is attached in such a manner that it is present on almost the entire surface of the guide surface 62a of the first guide member 62, excluding the bent surface 62b. In other words, the downstream ends 71e, 72e, and 73e of the narrow sections 71, 72, and 73 are approximately aligned with the downstream end 62e of the first guide member 62 in the transport direction C. Furthermore, the base portion 672 is in a state where it reaches the bent surface 62b.

[0089] Furthermore, the second auxiliary member 67 is attached to the first auxiliary member 66 by fastening means such as double-sided tape.

[0090] Furthermore, the narrow section 70 has a hypotenuse of a straight line that intersects with the planned passage position of at least one of the left and right ends 19c, 19d of the paper 19 during transport (see Figure 6). The dashed arrows in Figure 6 indicate the designed path (position) through which the left and right ends 19c, 19d of the paper 19 pass. In Embodiment 1, the narrow portions 72 and 73 are narrow portions having the hypotenuses 72a and 73a of a straight line through which the left and right ends 19c and 19d of the paper 19 pass.

[0091] In this embodiment, the paper transport path Rt employs a center register transport method. The center register transport method is a method in which the center of the paper 19 in the width direction D during transport is aligned with the center of the width direction D of the paper transport path Rt during transport. Furthermore, it is assumed that the paper transport path Rt of the image forming apparatus 10 is capable of transporting, for example, six different widths W1 to W6 of paper 19. In Figure 6, the symbols W1 to W6 represent six different widths.

[0092] The narrowest sections 72 and 73, positioned closest to the center, have hypotenuses 72a1 and 73a1 through which the left and right edges of the paper 19 with a minimum width W1 are expected to pass. The second narrowest section 72,73, positioned closer to the center, has hypotenuses 72a2,73a2 through which the left and right edges of the paper 19, which has a width W2 that is the next widest width W1, are expected to pass. The third narrow section 72,73, positioned closer to the center, has hypotenuses 72a3,73a3 through which the left and right edges of the paper 19, which has a width W3 that is the next widest width W2, are intended to pass. The fourth narrow section 72,73, positioned closer to the center, has hypotenuses 72a4,73a4 through which the left and right edges of the paper 19, which has a width W4 (the next widest width than W3), are intended to pass. The fifth narrowest section, 72,73, located closer to the center, has hypotenuses 72a5,73a5 through which the left and right edges of the paper 19, which has a width W5 (the next widest width than W4), are intended to pass. The narrowest sections 72 and 73, located at the outermost ends, have hypotenuses 72a6 and 73a6 through which the left and right edges of the paper 19 with a maximum width W6 are expected to pass.

[0093] In Embodiment 2, the narrow sections 72 and 73 have inclined sides such that the hypotenuses 72a and 73a are inclined toward the center in the width direction D with respect to the transport direction C. This makes it less likely for the transport orientation of the paper 19 to change even if the left and right edges of the paper 19 come into contact with the hypotenuses 72a and 73a as they pass. Specifically, there is no risk of the left and right edges of the paper 19 being guided to the left and right outer edges in the width direction D.

[0094] Furthermore, the narrow sections 72 and 73 are arranged such that the hypotenuses 72a and 73a exist symmetrically in the width direction D (see Figure 5). The dashed line J in Figure 5 is the linear axis indicating symmetry. This suppresses changes in the transport orientation when the hypotenuses 72a and 73a of the paper 19 come into contact with the transport system, even when a center register transport system is adopted. The linear axis J is positioned to approximately coincide with the center of the width direction D in the paper transport path Rt of the center register transport system. The narrow portion 71 located in the central region in Embodiment 1 is also arranged in a symmetrical relationship with respect to the width direction D.

[0095] Furthermore, the narrow sections 72 and 73 have parallel sides 72b and 73b on the opposite side from the hypotenuses 72a and 73a, which are parallel to the transport direction C. As a result, even if the left and right edges of the paper 19 come into contact with the narrow sections 72 and 73 as they pass, the contact area between the paper 19 and the narrow sections 72 and 73 is reduced compared to when there are no parallel sides 72b and 73b.

[0096] The narrow sections 72 and 73 are constructed as narrow sections whose planar shape is a right-angled triangle with the width direction D as its base. However, the narrow sections 72 and 73 differ in that their hypotenuses 72a and 73a are inclined in different directions (see Figure 6). Furthermore, the narrow section 71 is configured as a narrow section whose planar shape is an isosceles triangle with width D as its base. This isosceles triangle also includes equilateral triangles. As a result, the narrow section 71 narrows in width at the same rate on both sides in the transport direction C, and the change in contact state with the paper 19 is stabilized.

[0097] The paper guide device 6A can guide the paper 19 being transported within the transport space TA to move along the transport path Gr, which is illustrated by the dashed line in Figure 3. In other words, the paper guide device 6A guides the paper 19 by bringing it into contact with the auxiliary member 65 as the paper 19 moves along the guide surface 62a of the first guide member 62 of the transport guide section 61.

[0098] (Operation of the paper guide device) The paper guide device 6A guides the paper 19 as it is fed out and transported from the pair of transport rolls 46.

[0099] At this time, the guide surface 64a of the third guide member 64, the guide surface 62a of the first guide member 62, and the guide surface 63a of the second guide member 63 restrict the range of movement of the paper 19. As a result, the paper 19 moves through the transport space TA formed by the first guide member 62, the second guide member 63, and the third guide member 64 of the transport guide section 61. In other words, the paper 19 is transported by moving through the transport space TA as illustrated by the dashed line in Figure 7(A).

[0100] As a result, the paper 19 is guided to pass through the transport space TA and towards the destination secondary transfer position TP2. The paper guide device 6A guides the paper 19 so that it begins to contact the outer surface of the intermediate transfer belt 31 at a position Pf just before the secondary transfer position TP2. The position Pf is a position slightly before reaching the secondary transfer position TP2, as illustrated by the dashed ellipse in Figure 2. Incidentally, the secondary transfer position TP2 at the transport destination can also be described as the position where the image is formed on the paper 19. More precisely, it is the position where the unfixed image that will become the basis of the image is formed on the paper 19.

[0101] Furthermore, the paper guiding device 6A guides the paper 19 being transported along the guide surface 62a of the first guide member 62 by bringing it into contact with the auxiliary member 65.

[0102] At this time, the auxiliary member 65 first has the second auxiliary member 67, which has a narrow portion 70, come into contact with the paper 19. Subsequently, a portion of the first auxiliary member 66 comes into contact with the paper 19. The portion of the first auxiliary member 66 is at least a part of the portion of the first auxiliary member 66 that is exposed below the second auxiliary member 67. As a result, the paper 19 moves after coming into contact with the second auxiliary member 67 having a narrow portion 70, and then moves after coming into contact with a part of the first auxiliary member 66. In particular, the paper 19 moves after first coming into contact with at least a part of the narrow portion 70 of the second auxiliary member 67.

[0103] As a result, the paper 19 moves in contact with the second auxiliary member 67, which has a narrow portion 70, before it comes into contact with a part of the first auxiliary member 66. Therefore, the second auxiliary member 67 having the narrow portion 70 has a reduced contact area with the paper 19 compared to when the narrow portion 70 is absent. Furthermore, the contact between the second auxiliary member 67 and the paper 19 decreases as it moves in the transport direction C (see Figure 7(B)).

[0104] Therefore, in the paper guide device 6A, even if the paper 19 passes through continuously, the auxiliary member 65 gradually becomes charged, and the paper 19 does not or rarely stick to the auxiliary member 65 due to static electricity. In other words, with the paper guide device 6A, compared to the case where the auxiliary member 65 does not have a narrow portion 70, the paper 19 is less likely to stick to the auxiliary member 65 due to static electricity. In this case, the sticking occurs to the second auxiliary member 67 and to a part of the first auxiliary member 66.

[0105] Therefore, the paper guide device 6A also prevents the paper 19 from sticking to the auxiliary member 65 and causing a paper jam in the transport space TA. A paper jam is a malfunction also known as a jam. Furthermore, in the image forming apparatus 10 equipped with the paper guide device 6A, the paper 19 is transported smoothly to the secondary transfer position TP2.

[0106] Furthermore, in the paper guide device 6A, the paper 19 passes through the second auxiliary member 67 and then comes into contact with a part of the first auxiliary member 66 as it passes.

[0107] At this time, a portion of the first auxiliary member 66 that is not supported by the first guide member 62 elastically bends due to contact with the paper 19. This bending is a deformation in which the downstream end 66e of the first auxiliary member 66 elastically bends so that it approaches the intermediate transfer belt 31. As a result, the paper 19 is guided so that its leading edge 19a in the transport direction C approaches and contacts the outer surface of the intermediate transfer belt 31.

[0108] Furthermore, the paper guide device 6A has narrow sections 72 and 73, which are part of the narrow section 70, and these narrow sections have straight hypotenuses 72a and 73a. Therefore, in the paper guide device 6A, the left and right ends 19c and 19d of the transported paper 19 may come into contact with the hypotenuses 72a and 73a as it passes. Even in this case, the paper guide device 6A reduces the risk of the paper 19 being transported at an angle compared to the case where the narrow section 70 does not have hypotenuses. The case where the narrow section 70 does not have hypotenuses is when there is no hypotenuse of a straight line that intersects with the intended passage positions of the left and right ends 19c and 19d of the paper 19. As a result, the paper 19 is guided to contact the outer surface of the intermediate transfer belt 31 in the correct orientation and supplied to the secondary transfer position TP2.

[0109] (Evaluation test) Next, we will describe the evaluation tests conducted on the paper guide device 6A. In the evaluation test, the image forming apparatus 10 continuously transported paper 19 through paper guide devices with different configurations of auxiliary members 65. The evaluation test investigated the surface potential of each auxiliary member 65 and whether or not jams occurred during this process.

[0110] As a paper guiding device, various auxiliary members 65 were prepared, each individually attached to the guide surface 62a of the first guide member 62. One example is a paper guide device (embodiment) to which an auxiliary member 65 made of PP (half the area) having the narrow portion 70 described above is applied. Half the area means that, assuming that a portion of the original member, which has a rectangular planar shape, is cut off and the remaining portion is the area of ​​the auxiliary member 65, the planar area of ​​the auxiliary member 65 is half the area of ​​the original member.

[0111] One is a paper guide device (Comparative Example 1) that uses an auxiliary member 65 made of PET (total area) without the narrow section 70 mentioned above. Total area means the same area as the flat area of ​​the original member. In the evaluation test, the total area was approximately 9000 mm². 2 That's what I decided. One example is a paper guide device (Comparative Example 2) that uses an auxiliary member 65 made of PP (total area) without the narrow portion 70 mentioned above. One example is a paper guide device (reference example) to which an auxiliary member 65 made of PET (half the area) having the narrow portion 70 described above is applied.

[0112] The image forming apparatus 10 was operated at a process speed of 70 pmm (sheets / minute) in an environment of 28°C and 85% RH. For paper 19, we used A3-sized plain paper (manufactured by Oji Paper Co., Ltd.: recycled PPC). The surface potential of the auxiliary member 65 was measured periodically after a predetermined number of sheets had passed through it. The surface potential was measured using an electrostatic meter (Simco FNX-004). The presence or absence of jam formation was checked by measuring the surface potential of the auxiliary member 65 and then passing a sheet of A4-sized plain paper through it. The A4-sized plain paper used was plain paper with a moisture content of approximately 8% (Oji Paper Co., Ltd.: Recycled PPC, Fujifilm Business Innovation Co., Ltd.: C2).

[0113] The results of this evaluation test are shown in Figure 8. In the example, no jam occurred even when approximately 18,000 sheets (=1.8kV) of paper 19 were passed through. In Comparative Example 1, a jam occurred after only a small number of sheets (approximately 1000) of paper 19 had passed through. In Comparative Example 2, a jam occurred after approximately 15,000 sheets (=1.5kV) of paper 19 had passed through. Incidentally, in the example shown, a jam occurred after approximately 9000 sheets (=0.9kV) of paper 19 had passed through.

[0114] (Comparative study) Next, we will describe the comparative tests conducted on the auxiliary member 65 of the paper guide device 6A. In the comparative test, three types of sheets or similar materials were used as auxiliary members 65, with their surface area modified, and paper 19 was continuously transported through the paper guide device. During the comparative test, the surface potential of each auxiliary member 65 was periodically examined, in the same manner as in the evaluation test.

[0115] Three types of auxiliary materials were used for the auxiliary members 65: PET, PP, and POM. The planar area of ​​each auxiliary member 65 of the original member is approximately 9000 mm². 2 That's what I decided. Furthermore, the flat area of ​​each auxiliary member 65 was changed according to the width of the flat area of ​​the narrow section 70. Surface electricity was measured after transporting 18,000 sheets (=1.8kV) of A4-sized plain paper (recycled PPC, C2) as paper 19. The test environment was the same as that used for the evaluation test described above.

[0116] The results of this comparative study are shown in Figure 9. The comparative test results established an evaluation index where jamming does not occur if the surface voltage is -0.6kV or lower. As a result, it was found that the PP auxiliary member 65 can be made to a degree that does not cause jamming when a narrow section 70 is formed with a flat area of ​​less than half of the maximum area. Less than half of the maximum area is approximately 4500 mm². 2 The area is as follows: On the other hand, it was found that even when the flat area of ​​the PET auxiliary member 65 is reduced to a small area of ​​about 1 / 4 of its maximum area, it is difficult to prevent jamming.

[0117] (Other configurations of auxiliary members) The paper guide device 6A employs a second auxiliary member 67 having a narrower section 70, which is made of a material that is less prone to static charge than the first auxiliary member 66. A material that is less prone to static charge is, for example, a material whose triboelectric series is positioned on the side that is relatively less prone to static charge. Specifically, if a PET material is used as the first auxiliary member 66, a PP material is used as the second auxiliary member 67.

[0118] As a result, the paper guide device 6A is less likely to cause the paper 19 to stick to the first auxiliary member 66 due to static electricity compared to the following case. In this case, the paper 19 is also less likely to stick to the second auxiliary member 67 due to static electricity. The following case refers to the case where the second auxiliary member 67 is more prone to static charge than or to the same extent as the first auxiliary member 66.

[0119] Assuming that the narrow section 70 is the remaining portion after a part of the original member 670, which has a rectangular planar shape, the paper guide device 6A employs the following configuration. The original member 670 is a rectangular member that surrounds the narrow section 70, as illustrated by the dashed line in Figure 5, including the portion of the base 672 where the narrow section 70 exists. The following configuration is one in which the flat area of ​​the narrow section 70 is less than half the flat area of ​​the original member 670. In Embodiment 1, the flat area of ​​the narrow section 70 is the sum of the flat areas of the narrow section 70 and the base section 672.

[0120] As a result, the paper guide device 6A is less likely to cause the paper 19 to stick to the first auxiliary member 66 due to static electricity compared to the following case. In this case, the paper 19 is also less likely to stick to the second auxiliary member 67 due to static electricity. The following case is when the flat area of ​​the narrow portion 70 is larger than half the flat area of ​​the original member 670.

[0121] Embodiment 2. Figure 10 shows a reversal transport device 8 to which the paper guiding device 6B according to Embodiment 2 is applied. Figure 11 shows an enlarged view of the paper guiding device 6B from Figure 10.

[0122] The reversing transport device 8 transports the paper 19 that is being transported along the normal paper transport path Rt in such a way that its front and back sides are reversed and it joins the paper transport path Rt. The reversing conveying device 8 is equipped with the following six guide members as the conveying guide section 81: the first guide member 82, the second guide member 83, the third guide member 84, the fourth guide member 85, the fifth guide member 86, and the sixth guide member 87.

[0123] The first guide member 82 is a guide member having a guide surface 82a that forms a normal paper transport path Rt. The first guide member 82 is positioned with its guide surface 82a facing downwards and tilted so that the transport direction C of the paper 19 is in the upward direction.

[0124] The second guide member 83 is a guide member having a first guide surface 83a, a second guide surface 83b, and a third guide surface 83c. The second guide member 83 is, for example, a member with a shape having three sides. The three sides of the second guide member 83 are formed as the first guide surface 83a, the second guide surface 83b, and the third guide surface 83c. The second guide member 83 is positioned such that its upper edge becomes the first guide surface 83a, and its two sides that converge below become the second guide surface 83b and the third guide surface 83c. The second guide member 83 is positioned below the first guide member 82. The second guide member 83 is positioned such that its first guide surface 83a faces the guide surface 82a of the first guide member 82 with a predetermined distance between them.

[0125] The third guide member 84 is a guide member having a guide surface 84a. The third guide member 84 is positioned on the side of the second guide member 83 where the second guide surface 83b is located. The third guide member 84 is positioned such that the middle portion of the guide surface 84a faces the second guide surface 83b of the second guide member 83 at a predetermined distance. The guide surface 84a has a bent guide portion 84ac at its lower part. The bent guide portion 84ac is formed as a surface that is substantially parallel to and faces the upper part of the guide surface 87a of the sixth guide member 87, which will be described later.

[0126] The fourth guide member 85 is a guide member having a guide surface 85a. The fourth guide member 85 is positioned below the third guide member 84 and is connected to the lower end of the third guide member 84.

[0127] The fifth guide member 86 is a guide member having a guide surface 86a. The fifth guide member 86 is positioned on the side of the second guide member 83 where the third guide surface 83c is located. The fifth guide member 86 is positioned such that its guide surface 86a faces the third guide surface 83c of the second guide member 83 at a predetermined distance.

[0128] The sixth guide member 87 is a guide member having a guide surface 87a. The sixth guide member 87 is positioned below the fifth guide member 86 and connected to the lower end of the fifth guide member 86. The upper part of the guide surface 87a of the sixth guide member 87 is positioned opposite the lower part of the guide surface 84a of the third guide member 84 at a predetermined distance. The lower part of the guide surface 84a is the bent guide portion 84ac of the guide surface 84a. The lower part of the guide surface 87a of the sixth guide member 87 is positioned opposite the guide surface 85a of the fourth guide member 85 at a predetermined distance.

[0129] Furthermore, the reversing and conveying device 8 has conveying spaces TA1, TA2, TA3, TA4, and TA5.

[0130] The transport space TA1 is a transport space for normal transport. The transport space TA1 is formed between the guide surface 82a of the first guide member 82, the first guide surface 83a of the second guide member 83, and the upper part of the guide surface 84a of the third guide member 84. The transport space TA1 constitutes the normal paper transport path Rt.

[0131] The transport space TA2 is a transport space for branch introduction. The transport space TA2 is formed between the second guide surface 83b of the second guide member 83 and the guide surface 84a of the third guide member 84. The transport space TA3 is a transport space for pulling in. The transport space TA3 is formed between the lower part of the guide surface 85a of the fourth guide member 85 and the guide surface 86a of the fifth guide member 86 and the guide surface 87a of the sixth guide member 87.

[0132] Conveyor space TA4 is a conveyor space for return and discharge. Conveyor space TA4 is the same conveyor space as conveyor space TA3 and is used for both purposes. The transport space TA5 is a transport space for merging. The transport space TA5 is formed between the third guide surface 83c of the second guide member 83 and the guide surface 86a of the fifth guide member 86.

[0133] The reversing conveying device 8 also includes a conveying destination switching member 91 and a pair of conveying rolls 93, 94, and 95.

[0134] The transport destination switching member 91 is a member that switches the transport destination of the paper 19 being transported along the normal paper transport path Rt. The transport destination switching member 91 is driven to swing towards two stopping positions using the shaft 92 as a pivot point and then stop. The shaft 92 is positioned near the point where the first guide surface 83a and the second guide surface 83b of the second guide member 83 meet. The two stopping positions described above are the positions that block the transport space TA1 and the positions that block the transport space TA2 (see the state indicated by the dashed line in Figure 10).

[0135] When the transport destination switching member 91 swings to a position that blocks the transport space TA1, it switches the transport destination of the paper 19 to the branching introduction transport space TA2. When the transport destination switching member 91 swings to a position that blocks the transport space TA2, it switches the transport destination of the paper 19 to the transport space TA1 used for normal transport.

[0136] The pair of conveyor rolls 93 are for retraction. The pair of conveyor rolls 93 consists of a driven roll and a driven roll that rotate in the direction indicated by the dashed arrow. A pair of transport rolls 93 are positioned at predetermined locations within the transport space TA2 for branch introduction.

[0137] The pair of conveyor rolls 94 are forward and reverse-rotating conveyor rolls for retraction and discharge. The pair of conveyor rolls 94 consists of a driven roll and a driven roll that rotate in both directions, as indicated by the dashed double arrows. A pair of transport rolls 94 are positioned at predetermined locations in the transport space TA3 for retraction and the transport space TA4 for folding and unfolding.

[0138] The pair of conveyor rolls 95 are conveyor rolls for merging. The pair of conveyor rolls 95 consists of a driven roll and a driven roll that rotate in the direction indicated by the dashed arrow. A pair of conveyor rolls 95 are positioned in predetermined locations within the conveyor space TA5 for merging.

[0139] (Paper guide device) Furthermore, the reversing transport device 8 is equipped with a paper guiding device 6B. As shown in Figure 11, the paper guide device 6B includes at least a transport guide section 81 and an auxiliary member 65B.

[0140] In Embodiment 2, the paper guide device 6B constitutes a junction point where the transport path from transport space TA2 to transport space TA3 and the transport path from transport space TA4 to transport space TA5 merge. Furthermore, the paper guide device 6B is positioned such that the auxiliary member 65B connects the transport space TA4 and the transport space TA5. In this state, the auxiliary member 65B also covers the end of the transport space TA2.

[0141] In the paper guiding device 6B, a second guide member 83 is used as the transport guide section 81. Furthermore, the paper guide device 6B has an auxiliary member 65B attached to the lower end of the third guide surface 83c of the second guide member 83. It is preferable to provide a mounting recess at the lower end of the third guide surface 83c for attaching the auxiliary member 65B so that it is flush with the third guide surface 83c.

[0142] As shown in Figure 11, the auxiliary member 65B in Embodiment 2 is composed of a first auxiliary member 66 and two second auxiliary members 67A and 67B.

[0143] The first auxiliary member 66 is an auxiliary member that is attached to the third guide surface 83c of the second guide member 83 with one of the second auxiliary members 67A interposed between them. The other components of the first auxiliary member 66 are the same as those of the first auxiliary member 66 in Embodiment 1. The first auxiliary member 66 is attached such that the free end 66f opposite to the end attached to the third guide surface 83c of the second guide member 83 is close to or in contact with the lower end of the guide surface 84a of the third guide member 84. The area near the lower end of the guide surface 84a is close to the boundary with the bent guide portion 84ac.

[0144] The second auxiliary member 67A is attached to the third guide surface 83c of the second guide member 83 and is an auxiliary member having a narrow portion 70. In other words, the second auxiliary member 67A is attached to the side of the first auxiliary member 66 that faces the third guide surface 83c (see Figure 12). Figure 12 omits the illustration of the second auxiliary member 67B. The other second auxiliary member 67B is an auxiliary member having a narrow portion 70. The second auxiliary member 67B is attached to the third guide surface 83c of the first auxiliary member 66 and the surface opposite to the second auxiliary member 67A.

[0145] The other configurations of the second auxiliary members 67A and 67B are the same as those of the second auxiliary member 67 in Embodiment 1.

[0146] The second auxiliary member 67A is mounted such that its lower end 67f is slightly offset above the free end 66f of the first auxiliary member 66. The lower end 67f is the narrowest tip of the narrow section 70 and also corresponds to the downstream end of the narrow section 70. In this configuration, the lower end 67f of the second auxiliary member 67A is mounted close to the lower end of the guide surface 84a of the third guide member 84. On the other hand, the second auxiliary member 67B is attached such that its upper end 67h is slightly shifted upward from the free end 66f of the first auxiliary member 66. The upper end 67h is the narrowest tip of the narrow section 70 and also corresponds to the downstream end of the narrow section 70.

[0147] (Operation of the reversing transport device and paper guide device) The reversal transport device 8 guides and transports the paper 19 that has been introduced into the transport space TA2 for branch introduction toward the return stop position SP, which is the destination.

[0148] At this time, the paper 19 is transported in the transport direction C1 by the retraction transport roll 93. As a result, the paper 19 is fed from the transport space TA2 to the retraction transport space TA3 (see Figure 13(A)). At this time, the paper 19 moves by contacting and passing through the auxiliary member 65B of the paper guide device 6B, and is guided into the transport space TA3.

[0149] Next, the paper 19 is handed over to the transport roll 94 for retraction and discharge in the retraction transport space TA3 and transported in a predetermined amount. In other words, the paper 19 at this time is transported toward the return stop position SP, which is the destination. The paper 19 is transported until its rear end exits the branch introduction transport space TA2 and then stops.

[0150] The reversal stop position SP is the position where the drive of the transport rolls 94 for retraction and discharge stops, and the transport of the paper 19 ends and the paper stops. The reversal stop position SP is set, for example, within a predetermined range before and after the transport rolls 94 in the transport space TA3.

[0151] The paper guide device 6B operates as follows when the paper 19 is transported toward the folding stop position SP. In the paper guide device 6B, the portion of the paper 19 including its leading edge 19a passes through in contact with a part of the second auxiliary member 67A of the auxiliary member 65B. Subsequently, in the paper guide device 6B, the portion of the paper 19 including its leading edge 19a passes through in contact with a part of the first auxiliary member 66 of the auxiliary member 65B. The leading edge 19a of the paper 19 is the end of the paper when it is being transported in the transport direction C1.

[0152] As a result, the paper 19 moves in contact with the second auxiliary member 67A, which has a narrow portion 70, before it comes into contact with a part of the first auxiliary member 66. Therefore, the second auxiliary member 67A having the narrow portion 70 has a reduced contact area with the paper 19 compared to when the narrow portion 70 is absent. Furthermore, the contact of the second auxiliary member 67 with the paper 19 decreases as it moves in the transport direction C1.

[0153] Therefore, in the paper guide device 6B, even if the paper 19 passes continuously through the auxiliary member 65B in the transport direction C1, the auxiliary member 65B gradually becomes charged, and the paper 19 does not or rarely stick to the auxiliary member 65B due to static electricity. In other words, with the paper guide device 6B, compared to the case where the auxiliary member 65B does not have a narrow portion 70, the paper 19 is less likely to stick to the auxiliary member 65B due to static electricity. Therefore, the paper guide device 6A also prevents the paper 19 from sticking to the auxiliary member 65B and causing a paper jam in the transport space TA2.

[0154] Furthermore, the reversal transport device 8 guides and transports the paper 19 that has been transported to the reversal stop position SP toward the merging transport space TA5, which is the reversal destination.

[0155] At this time, the paper 19 is transported in the transport direction C2 with its rear end 19b leading by the reverse-rotating transport roll 94 for pulling in and ejecting. As a result, the paper 19 is sent from the transport space TA4 to the merging transport space TA5 (see Figure 13(B)). The rear end 19b is the end opposite to the front end 19a. Next, the paper 19 is transferred to the consolidation transport roll 95 and transported. In other words, at this point, the rear end of the paper 19 is fed out from the transport roll 95 and sent to the normal transport space TA1 for consolidation.

[0156] Through the above series of operations, the inversion transport device 8 transports the paper 19 so that it merges with the normal transport space TA1 with its front and back sides reversed.

[0157] The paper guide device 6B operates as follows when the paper 19 is transported toward the transport space TA5, which is the position to be folded. In the paper guide device 6B, the portion of the paper 19 including the rear end 19b often passes without contacting a part of the first auxiliary member 66 of the auxiliary member 65B.

[0158] However, the paper 19 may pass through in such a state that the portion including the rear end 19b comes into contact with a part of the first auxiliary member 66 of the auxiliary member 65B. Even in this case, the paper 19 moves after coming into contact with the second auxiliary member 67B, which has a narrow portion 70, before coming into contact with a part of the first auxiliary member 66. As a result, the paper 19 moves in contact with the second auxiliary member 67A, which has a narrow portion 70, before it comes into contact with a part of the first auxiliary member 66. Therefore, the second auxiliary member 67B having the narrow portion 70 has a reduced contact area with the paper 19 compared to when the narrow portion 70 is absent. Furthermore, the contact between the second auxiliary member 67B and the paper 19 decreases as it moves in the transport direction C2.

[0159] Therefore, in the paper guide device 6B, even if the paper 19 passes continuously through the auxiliary member 65B in the transport direction C2, the auxiliary member 65B gradually becomes charged, and the paper 19 does not or rarely stick to the auxiliary member 65B due to static electricity. In other words, with the paper guide device 6B, compared to the case where the auxiliary member 65B does not have a narrow portion 70, the paper 19 is less likely to stick to the auxiliary member 65B due to static electricity. Therefore, the paper guide device 6B also prevents the paper 19 from sticking to the auxiliary member 65B and causing a paper jam in the transport space TA2.

[0160] Therefore, the paper guide device 6B also prevents the paper 19 from sticking to the auxiliary member 65B and causing a paper jam in the transport space TA5, etc. Furthermore, the reversing transport device 8, which is equipped with a paper guide device 6B, can effectively reverse and transport the paper 19 without causing paper jams.

[0161] Variant expression. The present invention is not limited to the configuration examples illustrated in each of the above embodiments. The present invention can be modified as necessary, as long as it does not alter the gist of the invention as described as a means of solving the problem. Therefore, the present invention also includes, for example, the following modifications.

[0162] The auxiliary members 65 and 65B may consist only of auxiliary members having a narrow portion 70. In other words, the auxiliary members 65 and 65B may consist only of the second auxiliary member 67 having a narrow portion 70, and the first auxiliary member 66 may be omitted. This modification is effective when the guide surface 62a to which the auxiliary member 65 is attached, or the third guide surface 83c to which the auxiliary member 65B is attached, has properties that make it prone to static charge buildup.

[0163] The narrow portion 70 is not limited to having a triangular shape in its planar form. The narrow portion 70 may have a trapezoidal or semicircular shape in its planar form. Furthermore, the multiple narrow sections 70 are not limited to three types of narrow sections 71-73, but may also consist of two types of narrow sections or four or more types of narrow sections. Furthermore, the multiple narrow sections 70 may all have the same planar shape.

[0164] The paper guide device 6A is not limited to a paper transport device whose destination is the secondary transfer position TP2, but may also be a paper transport device whose destination is a position where another image is formed. The reversing transport device 8, which includes a paper guide device 6B, can be used as part of the paper transport path of the image forming apparatus 10. The paper guide devices 6A and 6B can also be applied to a side-register paper transport path. The side-register transport method is a method in which the paper 19 is transported by aligning the same side of the paper in the width direction D with one end of the paper transport path Rt.

[0165] The image forming apparatus 10 employing paper guide devices 6A and 6B is not particularly limited in terms of its image forming method or the type of image formed. Therefore, the image forming apparatus 10 may be an image forming apparatus that employs an image forming method such as an inkjet method or a printing method, rather than an electrophotographic method. Furthermore, the image forming apparatus 10 is not limited to forming multicolored images; it may also form monocolored images.

[0166] (Note) (((1))) A transport guide unit having a guide surface that guides the transported paper through and toward the destination, A chargeable auxiliary member attached to the guide surface to assist in the guidance, Equipped with, The auxiliary member is arranged in a width direction intersecting the paper transport direction and has a plurality of narrow sections having a shape in which the width narrows toward the transport direction. (((2))) The paper guide device according to (((1))), wherein the plurality of narrow sections have their downstream ends in the transport direction aligned with each other in the width direction. (((3))) The paper guide device according to (((1))) or (((2))), wherein some of the narrow sections of the plurality of narrow sections have a shape in which the hypotenuse of a straight line intersects with the planned passing position of at least one end of the left and right ends when the paper is being transported. (((4))) The narrow portion having the hypotenuse is inclined such that the hypotenuse faces toward the center in the width direction with respect to the transport direction (((3))) paper guide device as described in (((3))). (((5))) The narrow portion having the hypotenuse has a shape in which the opposite side of the hypotenuse has a parallel side that is parallel to the transport direction, as described in (((3))) or (((4))). (((6))) The paper guiding device according to any one of (((3))) to (((5))), wherein the remaining narrow portion other than the narrow portion having the hypotenuse has a planar shape that is an isosceles triangle with the width direction as its base. (((7))) The narrow portion having the hypotenuse is arranged such that the hypotenuse is symmetrical with respect to the line in the width direction, according to any of (((3))) to (((6))) the paper guiding device. (((8))) The paper guiding device according to any one of (((1))) to (((7))), wherein the auxiliary member comprises a first auxiliary member attached to the guide surface and a second auxiliary member having the narrow portion attached to the opposite side of the first auxiliary member from the guide surface. (((9))) The first auxiliary member is attached such that a portion of it protrudes from the downstream end of the guide surface in the transport direction. The paper guide device according to (8)), wherein the second auxiliary member is attached such that the downstream end of the narrow portion in the transport direction is shifted upstream in the transport direction compared to the downstream end of the first auxiliary member in the transport direction. (((10))) The paper guiding device according to (((8))) or (((9))), wherein the second auxiliary member is a member that is less prone to static charge than the first auxiliary member. (((11))) The paper guiding device according to any one of (((1))) to (((10))), wherein the auxiliary member is a film or sheet made of synthetic resin. (((12))) Assuming that the narrow portion is the part remaining after cutting off a portion of the original member which has a rectangular planar shape, the paper guide device according to any one of (((1))) to (((11))) wherein the planar area of ​​the narrow portion is less than or equal to half the planar area of ​​the original member. (((13))) The transport destination is the position where an image is formed on the paper, according to any of (((1))) to (((12))) the paper guiding device. (((14))) The transport destination is the paper guide device according to any one of (((1))) to (((13))) where the paper is folded and stopped at the folding point. (((15))) An image forming apparatus equipped with a paper guiding device as described in any of (((1))) to (((14))).

[0167] According to the paper guiding device described in (((1))), the tendency for the transported paper to stick to the electrostatically charged auxiliary member attached to the guide surface of the transport guide section to assist in guiding the paper can be suppressed compared to the case where the auxiliary member does not have multiple narrow sections that narrow in the direction of paper transport. According to the paper guide device described in (((2))), the paper is more easily transported stably compared to the case where the downstream ends of multiple narrow sections are not aligned in the width direction. According to the paper guiding device described in (((3))), the risk of the paper being transported at an angle is reduced compared to a device without a narrow section having a slanted edge. According to the paper guiding device described in (((4))), the risk of the paper being transported at an angle is reduced compared to the case where the slanted edge of the narrow part is inclined away from the center in the width direction with respect to the transport direction. According to the paper guiding device described in (((5))), the risk of the paper being transported at an angle is reduced compared to a case where the narrow section having a hypotenuse does not have a parallel side on the opposite side of the hypotenuse that is parallel to the transport direction. According to the paper guide device described in (((6))), the paper is more easily transported stably compared to when the remaining narrow section, other than the narrow section with the inclined section, has a planar shape other than an isosceles triangle (excluding an equilateral triangle). According to the paper guiding device described in (((7))), the paper is more easily transported stably without becoming skewed compared to the case where the narrow section with a hypotenuse is arranged so that the hypotenuse does not exist in a line-symmetric relationship in the width direction. According to the paper guiding device of (((8))), even if the first auxiliary member is a member that is easily charged, it is possible to suppress the paper from sticking to the first auxiliary member due to static electricity. In the paper guiding device according to (((9))), compared to the case where a part of the first auxiliary member is not mounted in a protruding state and the downstream end of the second auxiliary member is not mounted in a misaligned state, the paper is less likely to stick to the first auxiliary member due to static electricity, and the paper can be guided stably. According to the paper guiding device of (((10))), compared to the case where the second auxiliary member is more prone to static charge than or to the same extent as the first auxiliary member, the paper is less likely to stick to the first auxiliary member due to static electricity. According to the paper guide device described in (((11))), compared to cases where the auxiliary member is not a film or sheet made of synthetic resin, the paper can be transported stably by suppressing static electricity-induced sticking of the paper with an auxiliary member that has a simpler configuration. According to the paper guiding device of (((12))), the paper is less likely to stick to the auxiliary member due to static electricity compared to the case where the flat area of ​​the narrow part is larger than half the flat area of ​​the original member. According to the paper guiding device of (((13))), the paper can be guided toward the position where the image is formed while suppressing it from sticking to the auxiliary member by static electricity. According to the paper guiding device of (((14))), the paper can be guided toward the folding position and the position beyond the folding, while suppressing the paper from sticking to the auxiliary member by static electricity. According to the image forming apparatus described in (((15))), in the paper guiding device, the tendency for the transported paper to stick due to static electricity to an electrostatically charged auxiliary member attached to the guide surface of the transport guide section to assist in guiding the paper can be suppressed compared to the case where the auxiliary member does not have multiple narrow sections that narrow in the direction of paper transport. [Explanation of Symbols]

[0168] 6A, 6B... Paper guide device 10…Image forming apparatus 19… Paper 19c, 19d… both ends (left and right) 61,81…Transportation guidance section 62...First guide member (an example of a transport guide section having a guide surface) 62a... Guide surface 65, 65B... Auxiliary members 66...First auxiliary member 66e…Downstream end 67, 67A, 67B... Second auxiliary member 67e…Downstream end 70…Multiple narrow sections 71, 72, 73... Three types of narrow sections (an example of multiple narrow sections) 71e,72e,73e...downstream end 72, 73... Part of the narrow width of the three types of narrow sections 72a, 73a... Hypotenuses of the straight lines 72b, 73b… Parallel sides 83...Second guide member (another example of a transport guide section having a guide surface) 83c...Third guide surface (another example of a guide surface) 670... Original component C, C1, C2... Conveying direction D…Width direction TP2…Secondary transfer position (an example of the position where an image is formed on the paper) SP...Turnaround stopping position TA5…Conveyor space (an example of the return destination location)

Claims

1. A transport guide unit having a guide surface that guides the transported paper through and toward the destination, A chargeable auxiliary member attached to the guide surface to assist in the guidance, Equipped with, The auxiliary member is arranged in a width direction intersecting the paper transport direction and has a plurality of narrow sections having a shape in which the width narrows toward the transport direction.

2. The paper guiding device according to claim 1, wherein the downstream ends of the plurality of narrow sections in the transport direction are aligned with each other in the width direction.

3. The paper guide device according to claim 1, wherein some of the narrow portions of the plurality of narrow portions have a shape in which the hypotenuse of a straight line intersects with the intended passing position of at least one end of the left and right ends when the paper is being transported.

4. The paper guiding device according to claim 3, wherein the narrow portion having the slanted side is inclined such that the slanted side faces toward the center in the width direction with respect to the transport direction.

5. The paper guiding device according to claim 3, wherein the narrow portion having the hypotenuse has a parallel side on the opposite side from the hypotenuse that is parallel to the transport direction.

6. The paper guiding device according to claim 3, wherein the remaining narrow portion other than the narrow portion having the hypotenuse has a planar shape that is an isosceles triangle with the width direction as its base.

7. The paper guiding device according to claim 3, wherein the narrow portion having the hypotenuse is arranged such that the hypotenuse exists in a line-symmetric relationship in the width direction.

8. The paper guiding device according to claim 1, wherein the auxiliary member comprises a first auxiliary member attached to the guide surface and a second auxiliary member having the narrow portion attached to the opposite side of the first auxiliary member from the guide surface.

9. The first auxiliary member is attached such that a portion of it protrudes from the downstream end of the guide surface in the transport direction. The paper guiding device according to claim 8, wherein the second auxiliary member is attached such that the downstream end of the narrow portion in the transport direction is offset to the upstream side in the transport direction compared to the downstream end of the first auxiliary member in the transport direction.

10. The paper guiding device according to claim 9, wherein the second auxiliary member is a member that is less prone to static charge than the first auxiliary member.

11. The paper guiding device according to claim 1, wherein the auxiliary member is a film or sheet made of synthetic resin.

12. Assuming that the narrow portion is the part remaining after cutting off a portion of the original member which has a rectangular planar shape, the paper guide device according to claim 1, wherein the planar area of ​​the narrow portion is less than or equal to half the planar area of ​​the original member.

13. The paper guiding device according to claim 1, wherein the destination of the transport is a position where an image is formed on the paper.

14. The paper guiding device according to claim 1, wherein the transport destination is the position where the paper is folded and where it is folded.

15. An image forming apparatus comprising a paper guiding device according to any one of claims 1 to 14.

Images