Medium conveying device and image forming device

Abstract

The present invention provides a medium conveying device and an image forming device, which maintain conveying performance with a simple structure and suppress friction charging or scratches on paper, compared with a structure in which a portion in contact with the medium is formed over the entire area in the width direction or conveying direction. A medium conveying device (BH), characterized in that it includes: a conveying member (1) that supports and conveys a medium (S); and a guiding member (11) that is arranged at a position offset in the width direction of the medium (S) relative to the conveying member (1) to guide the medium (S) and has a contact portion (12) that contacts the medium (S), and the contact portion (12) is arranged at a distance relative to the conveying direction of the medium (S).

Description

Technical Field

[0001] The invention relates to a medium conveying device and an image forming device. Background Art

[0002] Regarding a medium transport device for transporting a medium such as paper or an overhead projector (OHP) sheet in an image forming apparatus such as a copier, a printer, or a facsimile (FAX), the technologies described in the following Patent Documents 1 and 2 are known.

[0003] Japanese Patent Application Laid-Open No. 2019-95571, which is Patent Document 1, describes a structure in which an upstream guide 41 between the transfer belt 24 and the fixing device 30 is provided with a protrusion 44 that protrudes from the back side of the paper P relative to the straight path R1 of the paper P. In the technology described in Patent Document 1, the paper P conveyed from the transfer belt 24 is placed on the protrusion 44 so that the paper P does not contact the introduction portion 43 on the upstream side of the protrusion 44. When the paper P reaches the downstream guide 42, the paper P is conveyed in a state in which the downstream guide 42 and the protrusion 44 are in contact.

[0004] Japanese Patent Laying-Open No. 2012-103422, which is Patent Document 2, describes the following structure: a rotating belt 81 for sucking and conveying the paper P is arranged in the central portion in the width direction, and a retaining edge 82a extending in the conveying direction is arranged outside the rotating belt 81 in the width direction, and the paper P is guided by the retaining edge 82a.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-95571 ("0040"-"0054", Figure 1 -Figure 9)

[0008] [Patent Document 2] Japanese Patent Publication No. 2012-103422 ("0022"-"0027", Figure 2 ) Summary of the invention

[0009] [Problems to be solved by the invention]

[0010] The present invention sets as a technical problem to maintain conveyance performance and suppress frictional electrification or scratches on paper with a simple structure, compared with a structure in which a portion in contact with a medium is formed over the entire area in the width direction or the conveyance direction.

[0011] [Technical means to solve the problem]

[0012] In order to solve the above technical problems, the medium transport device of the invention described in technical solution 1 includes:

[0013] A transport component that supports and transports the medium; and

[0014] The guide member is arranged at a position offset from the conveying member in the width direction of the medium, guides the medium, and has a contact portion that contacts the medium, the contact portion being arranged at a distance with respect to the conveying direction of the medium.

[0015] In the invention described in claim 2: In the medium transport device described in claim 1,

[0016] The guide member is provided on the outer side in the width direction relative to the conveying member.

[0017] In the invention described in claim 3: In the medium transport device described in claim 1 or claim 2,

[0018] The intermediate portion between the contact portions is formed in a slope shape along the conveyance direction of the medium, with the height in the gravity direction becoming higher as it goes to the downstream side.

[0019] In the invention described in claim 4: In the medium transport device described in claim 3,

[0020] The intermediate portion is formed in a convex shape facing downward with respect to the direction of gravity.

[0021] In the invention described in claim 5: In the medium transport device described in any one of claims 1 to 4,

[0022] The second guide member is disposed on an upstream side of the guide member along a medium conveying direction, guides the medium, and has a convex strip extending along the medium conveying direction.

[0023] In the invention described in claim 6: In the medium transport device described in any one of claims 1 to 5,

[0024] The height of the top of the contact portion is lower than the height of the medium supported by the conveying member.

[0025] In the invention described in claim 7: In the medium transport device described in any one of claims 1 to 6,

[0026] The conveying member includes an endless belt-shaped member that supports the medium on the surface and rotates, and an adsorption member that adsorbs the medium to the belt-shaped member.

[0027] In the invention described in claim 8: In the medium transport device described in any one of claims 1 to 7,

[0028] The contact portion includes a convex shape extending in a width direction of the medium.

[0029] In the invention described in claim 9: In the medium transport device described in claim 8,

[0030] The contact portion includes a plurality of the convex-shaped contact portions arranged at intervals in a width direction of the medium.

[0031] In the invention described in claim 10: In the medium transport device described in claim 8 or claim 9,

[0032] The contact portion includes a convex shape that is inclined toward the downstream side in the conveyance direction as it goes outward in the width direction.

[0033] In the invention described in claim 11: In the medium transport device described in any one of claims 1 to 10,

[0034] The contact portion is provided in plurality and arranged at intervals with respect to the conveyance direction and the width direction of the medium.

[0035] In order to solve the above technical problems, the image forming device of the invention described in claim 12 includes:

[0036] Like holding parts;

[0037] a transfer component for transferring the image on the surface of the image holding component to a medium;

[0038] The medium conveying device described in any one of the technical solutions 1 to 11 conveys a medium to which an image is transferred; and

[0039] The fixing device fixes the image on the medium transported by the medium transport device.

[0040] [Effects of the Invention]

[0041] According to the invention described in claim 1 and claim 12, compared with a structure in which a portion in contact with the medium is formed over the entire area in the width direction or the conveying direction, it is possible to maintain conveyance performance with a simple structure and suppress frictional charging or scratches on paper.

[0042] According to the invention described in claim 2, compared with the case where the conveying member is arranged on the outer side in the width direction, it is possible to suppress the medium from being conveyed at an inclination.

[0043] According to the invention described in claim 3, compared with a case where the height in the gravity direction does not increase as the medium goes to the downstream side, it is possible to suppress the medium from getting caught and clogging.

[0044] According to the invention described in claim 4, compared with a case where the middle portion is not formed into a downwardly convex shape, the medium can be less likely to contact the middle portion just before the contact portion, thereby suppressing frictional electrification.

[0045] According to the invention described in claim 5, compared with a case where the second guide member is not provided, occurrence of paper jam can be suppressed.

[0046] According to the invention described in claim 6, the contact pressure applied to the passing medium can be reduced compared to a case where the height of the top of the contact portion is higher than the height of the supporting medium.

[0047] According to the invention described in claim 7, the medium can be transported more reliably compared to a case where the belt-shaped member and the adsorption member are not provided.

[0048] According to the invention described in claim 8, compared with a structure in which the convex strips extend in the conveying direction, it is possible to suppress the contact position with the convex strips from being charged linearly.

[0049] According to the invention described in claim 9, compared with the case where the convex shape is continuous in the width direction, the contact area can be reduced, thereby suppressing frictional electrification.

[0050] According to the invention described in claim 10, compared with a case where the convex shape does not incline toward the downstream side in the conveyance direction as it goes outward in the width direction, wrinkles of the medium can be suppressed.

[0051] According to the invention described in claim 11, the contact area can be further reduced compared to the case where the contact is continuous in the width direction, thereby suppressing frictional electrification. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is an overall explanatory diagram of the image forming apparatus of Embodiment 1.

[0053] Figure 2 This is an enlarged explanatory diagram of the visible image forming device of Example 1.

[0054] Figure 3 It is a perspective view of the medium transport device of Example 1.

[0055] Figure 4 is from Figure 3 The figure is viewed from the direction of arrow IV.

[0056] Figure 5 yes Figure 3 VV line profile.

[0057] Figure 6 This is an explanatory diagram of the main parts of the guide member of Example 1.

[0058] Fig. 7A and Figure 7B is an explanatory diagram of Modification 1 and Modification 2. Fig. 7A is an explanatory diagram of Modification Example 1. Figure 7B This is an explanatory diagram of Modification Example 2.

[0059] Fig. 8A and Figure 8B is an explanatory diagram of Modification 3 and Modification 4 of Embodiment 1, Fig. 8A is an explanatory diagram of Modification Example 3. Figure 8B This is an explanatory diagram of Modification Example 4.

[0060] Fig.9A and Fig. 9B is an explanatory diagram of Modification 5 and Modification 6 of Embodiment 1, Fig.9A is an explanatory diagram of Modification Example 5. Fig. 9B This is an explanatory diagram of Modification Example 6.

[0061] [Explanation of Symbols]

[0062] 1: Transport parts

[0063] 2: Strip parts

[0064] 6: Adsorption components

[0065] 11: Guide components

[0066] 12, 31, 32, 33: Contact part

[0067] 13: Middle

[0068] 16: Second guide member

[0069] 17: convex strips

[0070] BH: Media transport device

[0071] F: Fixing device

[0072] Py, Pm, Pc, Pk: Image holding parts

[0073] S: Medium

[0074] T1+T2+B: Transfer parts

[0075] U: Image forming device DETAILED DESCRIPTION

[0076] Next, specific examples (hereinafter referred to as examples) of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.

[0077] In addition, in order to facilitate understanding of the subsequent description, in the accompanying drawings, the front-to-back direction is set as the X-axis direction, the left-to-right direction is set as the Y-axis direction, the up-down direction is set as the Z-axis direction, and the directions or sides indicated by arrow X, arrow -X, arrow Y, arrow -Y, arrow Z, and arrow -Z are set as front, rear, right, left, top, bottom, or front side, rear side, right side, left side, top side, and bottom side, respectively.

[0078] In the drawings, a circle with “·” in it indicates an arrow pointing from the back side to the front side of the paper, and a circle with “×” in it indicates an arrow pointing from the front side to the back side of the paper.

[0079] In the following description using the drawings, for easy understanding, illustration of components other than those necessary for the description is omitted as appropriate.

[0080] [Example 1]

[0081] Figure 1 This is an overall explanatory diagram of the image forming apparatus of Embodiment 1.

[0082] Figure 2 This is an enlarged explanatory diagram of the visible image forming device of Example 1.

[0083] exist Figure 1 In the figure, a copier U as an example of an image forming device includes: a user interface UI as an example of an operating unit, a scanner unit U1 as an example of an image reading device, a feeder unit U2 as an example of a medium supply device, an imaging unit U3 as an example of an image recording device, and a medium processing device U4.

[0084] (Description of the user interface UI)

[0085] The user interface UI includes input buttons UIa for starting copying or setting the number of copies, etc. The user interface UI also includes a display unit UIb for displaying the contents inputted through the input buttons UIa or the status of the copy machine U.

[0086] (Description of Feeder Unit U2)

[0087] exist Figure 1In the image forming unit U3, the feeder unit U2 has a plurality of paper feed trays TR1, TR2, TR3, and TR4 as an example of a medium storage container. In addition, the feeder unit U2 has a medium supply path SH1, etc., and the medium supply path SH1 takes out recording paper S as an example of a medium for image recording stored in the paper feed trays TR1 to TR4 and conveys it to the image forming unit U3.

[0088] (Description of Imaging Unit U3 and Medium Processing Device U4)

[0089] exist Figure 1 In the image forming unit U3, the image forming unit U3 includes an image recording unit U3a for recording an image on the recording paper S conveyed from the feeder unit U2 based on the document image read by the scanner unit U1.

[0090] exist Figure 1 , Figure 2 In the present invention, the driving circuit D of the latent image forming device of the imaging unit U3 outputs a driving signal corresponding to the image information to the latent image forming devices ROSy, ROSm, ROSc, and ROSk of each color Y to K at a preset time according to the image information input from the scanner unit U1. Below each of the latent image forming devices ROSy to ROSk, a photosensitive drum Py, a photosensitive drum Pm, a photosensitive drum Pc, and a photosensitive drum Pk are arranged as an example of an image holding body.

[0091] The surfaces of the rotating photosensitive drums Py, Pm, Pc, and Pk are charged in the same manner by charging rollers CRy, CRm, CRc, and CRk, which are examples of charging devices. Electrostatic latent images are formed on the surfaces of the charged photosensitive drums Py to Pk by laser beams Ly, Lm, Lc, and Lk, which are examples of latent image writing light, output by latent image forming devices ROSy, ROSm, ROSc, and ROSk. The electrostatic latent images on the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are developed into toner images of yellow (Y), magenta (M), cyan (C), and black (K), which are examples of visible images, by developing devices Gy, Gm, Gc, and Gk.

[0092] In the developing devices Gy to Gk, the developer consumed by development is replenished from toner cartridges Ky, Km, Kc, and Kk, which are examples of developer storage containers. The toner cartridges Ky, Km, Kc, and Kk are detachably mounted on the developer replenishing device U3b.

[0093] The toner images on the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are repeatedly transferred to the primary transfer area Q3y, Q3m, Q3c, and Q3k on the intermediate transfer belt B as an example of an intermediate transfer body by the primary transfer rollers T1y, T1m, T1c, and T1k as an example of a primary transfer device, thereby forming a color toner image as an example of a multi-color visible image on the intermediate transfer belt B. The color toner image formed on the intermediate transfer belt B is conveyed to the secondary transfer area Q4.

[0094] In addition, in the case of only K-color image information, only the K-color photosensitive drum Pk and the developing device Gk are used to form only a K-color toner image.

[0095] After the primary transfer, the photosensitive drum Py, photosensitive drum Pm, photosensitive drum Pc, and photosensitive drum Pk are cleaned of residual developer, paper powder, and other residues attached to the surface by drum cleaners CLy, CLm, CLc, and CLk, which are examples of cleaners for image retaining bodies.

[0096] In the first embodiment, the photosensitive drum Pk, the charging roller CRk, and the drum cleaner CLk are integrated as a photosensitive unit UK of color K, which is an example of an image holding unit. In addition, regarding other colors Y, color M, and color C, similarly, the photosensitive drum Py, photosensitive drum Pm, photosensitive drum Pc, the charging roller CRy, charging roller CRm, charging roller CRc, and the drum cleaner CLy, drum cleaner CLm, and drum cleaner CLc constitute the photosensitive unit UY, photosensitive unit UM, and photosensitive unit UC.

[0097] In addition, the K-color photosensitive body unit UK and the developing device Gk having the developing roller R0k as an example of the developer holding body constitute the K-color visible image forming device UK+Gk. Similarly, the Y-color, M-color, C-color photosensitive body unit UY, the photosensitive body unit UM, the photosensitive body unit UC, and the developing devices Gy, Gm, and Gc having the developing rollers R0y, R0m, and R0c respectively constitute the Y-color, M-color, C-color visible image forming device UY+Gy, the visible image forming device UM+Gm, and the visible image forming device UC+Gc.

[0098] Below the photosensitive drums Py to Pk, a belt module BM as an example of an intermediate transfer device is arranged. The belt module BM includes an intermediate transfer belt B as an example of an image holding member, a driving roller Rd as an example of a driving member of the intermediate transfer body, a tension roller Rt as an example of a tension imparting member, a travel roller Rw as an example of a meandering prevention member, a plurality of idle rollers Rf as an example of a driven member, and a support roller T2a as an example of an opposing member, as well as the primary transfer rollers T1y, T1m, T1c, and T1k. The intermediate transfer belt B is supported so as to be rotatable in the direction of the arrow Ya.

[0099] A secondary transfer unit Ut is arranged below the support roller T2a. The secondary transfer unit Ut has a secondary transfer roller T2b as an example of a secondary transfer member. A secondary transfer area Q4 is formed by an area where the secondary transfer roller T2b contacts the intermediate transfer belt B. In addition, the support roller T2a as an example of an opposing member faces the secondary transfer roller T2b across the intermediate transfer belt B. The contact roller T2c as an example of a power supply member contacts the support roller T2a. A secondary transfer voltage having the same polarity as the charged polarity of the toner is applied to the contact roller T2c.

[0100] The backup roller T2 a , the secondary transfer roller T2 b , and the contact roller T2 c constitute a secondary transfer device T2 as an example of a transfer member.

[0101] A medium conveying passage SH2 is arranged below the belt assembly BM. The recording paper S supplied from the medium supply passage SH1 of the feeder section U2 is conveyed toward a register roller Rr, which is an example of a member for adjusting the conveying period, by a conveying roller Ra, which is an example of a member for conveying the medium. The register roller Rr conveys the recording paper S toward the downstream side in accordance with the period when the toner image formed on the intermediate transfer belt B is conveyed to the secondary transfer area Q4. The recording paper S fed by the register roller Rr is guided by the paper guide SGr on the register side and the paper guide SG1 before transfer, and is conveyed to the secondary transfer area Q4.

[0102] When the toner image on the intermediate transfer belt B passes through the secondary transfer area Q4, it is transferred to the recording paper S by the secondary transfer device T2. In the case of a color toner image, the toner image that has been repeatedly transferred to the surface of the intermediate transfer belt B is also transferred to the recording paper S by the secondary transfer device T2.

[0103] The primary transfer rollers T1y to T1k, the secondary transfer device T2, and the intermediate transfer belt B constitute the transfer devices T1y to T1k+T2+B of the first embodiment.

[0104] The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLB as an example of an intermediate transfer body cleaner arranged on the downstream side of the secondary transfer area Q4. The belt cleaner CLB as an example of a removal member removes residual materials such as developer and paper powder that remain without being transferred in the secondary transfer area Q4 from the intermediate transfer belt B.

[0105] The recording paper S to which the toner image has been transferred is guided by the paper guide SG2 after the transfer and is conveyed to the belt conveyor BH as an example of a medium conveying device.

[0106] The fixing device F includes a heating roller Fh as an example of a heating member and a pressure roller Fp as an example of a pressure member. The recording paper S is conveyed to a fixing area Q5 as an area where the heating roller Fh and the pressure roller Fp are in contact. The toner image on the recording paper S is heated and pressed by the fixing device F to be fixed while passing through the fixing area Q5.

[0107] The visible image forming device UY+Gy to the visible image forming device UK+Gk, the transfer devices T1y to T1k+T2+B, and the fixing device F constitute an image recording section U3a as an example of an image forming member of the first embodiment.

[0108] On the downstream side of the fixing device F, a switching gate GT1 as an example of a switching member is provided. The switching gate GT1 selectively switches the recording paper S that has passed through the fixing area Q5 to either the discharge path SH3 or the reversing path SH4 on the side of the medium processing device U4. The recording paper S that has been conveyed to the discharge path SH3 is conveyed toward the paper conveying path SH5 of the medium processing device U4. In the paper conveying path SH5, a curl correction member U4a as an example of a bending correction member is arranged. The curl correction member U4a corrects the bending, so-called curl, of the recording paper S that has been conveyed. The recording paper S with the corrected curl is discharged toward the discharge tray TH1 as an example of a medium discharge portion by the discharge roller Rh as an example of a medium discharge member in a state where the image fixing surface of the paper faces upward.

[0109] The recording paper S conveyed toward the reversing path SH4 of the image forming unit U3 by the switching gate GT1 passes through the second gate GT2 as an example of a switching member, and is conveyed to the reversing path SH4 of the image forming unit U3 .

[0110] At this time, when the recording paper S is discharged with the image fixing surface facing downward, the conveying direction of the recording paper S is reversed after the rear end of the recording paper S in the conveying direction passes through the second gate GT2. Here, the second gate GT2 of the first embodiment includes a film-like elastic member. Therefore, the second gate GT2 allows the recording paper S that has been conveyed to the reversing path SH4 to pass through directly temporarily, and if the recording paper S that has passed through is reversed, that is, switched back, it is guided to the conveying path SH3 and the conveying path SH5 side. Moreover, the recording paper S that has been switched back passes through the curl correction member U4a and is discharged to the discharge tray TH1 with the image fixing surface facing downward.

[0111] The reversing passage SH4 of the image forming unit U3 is connected to the circulation passage SH6, and a third gate GT3 as an example of a switching member is disposed at the connection portion of the two. The downstream end of the reversing passage SH4 is connected to the reversing passage SH7 of the medium processing device U4.

[0112] The recording paper S conveyed to the reversing path SH4 through the switching gate GT1 is conveyed toward the reversing path SH7 side of the media processing device U4 through the third gate GT3. The third gate GT3 of the first embodiment includes a film-like elastic member similar to the second gate GT2. Therefore, the third gate GT3 allows the recording paper S conveyed on the reversing path SH4 to temporarily pass through, and if the recording paper S that has passed through is turned back, it is guided toward the circulation path SH6 side.

[0113] The recording paper S conveyed to the circulation path SH6 passes through the medium conveyance path SH2 and is conveyed again to the secondary transfer area Q4 to perform printing on the second side.

[0114] The paper conveying path SH is constituted by the elements indicated by the above reference numerals SH1 to SH7. The paper conveying device SU of the first embodiment is constituted by the elements indicated by the above reference numerals SH, Ra, Rr, Rh, SGr, SG1, SG2, BH, and GT1 to GT3.

[0115] (Description of the medium transport device)

[0116] Figure 3 It is a perspective view of the medium transport device of Example 1.

[0117] Figure 4 is from Figure 3 The figure is viewed from the direction of arrow IV.

[0118] Figure 5 yes Figure 3 VV line profile.

[0119] exist Figure 3-Figure 5 In the embodiment 1, the belt conveying device BH has a conveying belt 1 as an example of a conveying member. The conveying belt 1 is arranged in the center of the front-back direction which is the width direction of the recording paper S. The conveying belt 1 has an annular belt body 2 as an example of a belt-like member, and the belt body 2 is an example of a body of the conveying member. A plurality of openings 2a are formed in the belt body 2.

[0120] The belt body 2 is supported in a state of being suspended by a driving roller 3 as an example of a driving member and a driven roller 4 as an example of a driven member. In the first embodiment, the driving roller 3 is arranged on the downstream side of the conveying direction of the recording paper S, and the driven roller 4 is arranged on the upstream side. The rotating shaft 3a of the driving roller 3 is extended toward the rear, and the gear 3b as an example of a driving transmission member is supported at the rear end of the rotating shaft 3a. Therefore, if the drive is transmitted from the driving source (not shown) provided in the imaging unit U3 to the gear 3b, the driving roller 3 rotates and the belt body 2 rotates.

[0121] A suction duct 6 as an example of an adsorption member is disposed inside the belt body 2. A fan 7 as an example of an air transfer member is supported at the rear end of the suction duct 6. When the fan 7 is operated, the suction duct 6 sucks air through the opening 2a of the belt body 2. Therefore, if there is a recording paper S on the upper surface of the belt body 2, the recording paper S is adsorbed to the surface of the belt body 2.

[0122] Figure 6 This is an explanatory diagram of the main parts of the guide member of Example 1.

[0123] exist Figure 3-Figure 5 In the embodiment 1, a ripple guide 11 as an example of a guide member is arranged on the outside of the belt body 2 in the width direction of the recording paper S. A corrugated top portion 12 as an example of a contact portion is formed on the upper surface of the ripple guide 11. The corrugated top portion 12 can contact the lower surface of the recording paper S to guide the recording paper S. A plurality of corrugated top portions 12 of the embodiment 1 are arranged at intervals along the conveying direction of the recording paper S. In addition, the corrugated top portion 12 is extended along the front-to-back direction which is the width direction. Figure 5 , Figure 6 In the embodiment 1, the height of the top of the wave top 12 is set to be lower than the height of the surface of the belt body 2. That is, in the embodiment 1, the top of the wave top 12 is configured so as not to protrude further than the belt body 2.

[0124] exist Figure 6 In the ripple guide 11 of the first embodiment, the middle portion 13 between the wave tops 12 is formed into an inclined surface shape with the height in the gravity direction becoming higher as it goes to the downstream side along the conveying direction of the recording paper S. In particular, in the first embodiment, as Figure 6As shown in FIG. 1 , the middle portion 13 includes a convex inclined surface facing downward relative to the direction of gravity. That is, the middle portion 13 includes a convex curved surface 13a facing downward, rather than a curved surface 13a formed by Figure 6 Therefore, near the top portion 12, the curved surface 13a of the middle portion 13 is recessed downward compared to the flat inclined surface 13b, and the apex of the wavelength portion 12 is sharp. In addition, the interval between the top portions 12 of Example 1 in the conveying direction is set to an interval such that even if a thin paper with low rigidity is bent, the thin paper will not stick to the middle portion 13.

[0125] exist Figure 3-Figure 5 In the embodiment, an introduction guide 16 as an example of a second guide member is provided on the upstream side of the ripple guide 11 along the conveying direction of the recording paper S. The introduction guide 16 is formed in a flat plate shape. On the upper surface of the introduction guide 16, a plurality of convex strips 17 extending along the conveying direction are formed. The convex strips 17 of Example 1 are arranged at a position corresponding to the width of the recording paper S of a fixed size such as A4 or B5, and are arranged at a position slightly inside the fixed width in a manner that can contact the lower surface of the end of the width direction of the fixed recording paper S to guide it. The introduction guide 16 of Example 1 guides the recording paper S from the transferred paper guide SG2 to the ripple guide 11, and the length in the conveying direction is formed to be about the length of one pitch of the wave top 12.

[0126] (Effect of Example 1)

[0127] In the copier U of the first embodiment having the above-described structure, the recording paper S to which the image is transferred in the secondary transfer area Q4 is guided by the post-transfer paper guide SG2 while the image is not fixed, and is conveyed to the belt conveyor BH. The recording paper S that has reached the belt conveyor BH is attracted to the conveyor belt 1, and is conveyed toward the fixing device F on the downstream side as the conveyor belt 1 rotates.

[0128] On the outer side in the width direction of the conveyor belt 1, the recording paper S is guided by the introduction guide 16 and then by the ripple guide 11. The vicinity of the top of the wave top 12 of the ripple guide 11 contacts the portion of the recording paper S not attracted to the conveyor belt 1, and guides the recording paper S to the downstream side.

[0129] In the past, guide members, such as the structure described in Patent Document 2, have formed guide ribs such as the ridges 17 of the introduction guide 16 over the entire area in the conveying direction in order to reduce the contact area with the recording paper S and thereby suppress the conveying resistance or friction charging. However, in this structure, when the recording paper S passes through, the guide ribs are continuously contacted at the same position in the width direction of the recording paper S, resulting in a state where only the contacted portion is significantly frictionally charged, and the other portions are not frictionally charged. Therefore, there is a situation where, due to the deviation in the charging state, the unfixed developer is scattered in the frictionally charged linear portion, resulting in linear image quality defects.

[0130] In the technology described in Patent Document 1, the paper P is guided in a state where the protrusion 44 extending in the width direction rather than the conveying direction contacts the lower surface of the paper P. However, in the structure described in Patent Document 1, the paper P is supported by only one part of the protrusion 44, and there is a concern that the contact pressure at the position of the protrusion 44 becomes high, the amount of frictional electrification is likely to increase, or scratches may occur.

[0131] In addition, there may be a structure in which the entire area in the width direction includes the conveyor belt and does not have the ripple guide 11 of Example 1. However, a homogeneous belt must be made in the entire area in the width direction of the belt, or the rollers for mounting the belt (equivalent to the driving roller 3 and the driven roller 4 of Example 1) must be made uniformly in the axial direction, or the attraction force must be made uniform in the width direction. Therefore, there are also the following problems: the longer the length in the width direction of the belt, the stricter the precision becomes, the higher the manufacturing cost, or the additional structure required to ensure the precision, and the structure is easy to be complicated. In addition, it is not realistic to uniformly produce the wear of the belt or roller over time in the entire area in the width direction, and the recording paper is easy to tilt (skew) due to uneven wear. Moreover, if a belt is provided in the entire area in the width direction, the influence of uneven wear is easy to become larger, and the conveying performance (skew) is easy to deteriorate.

[0132] In view of these problems, in the ripple guide 11 of Example 1, a plurality of wave tops 12 are provided at intervals in the conveying direction. Therefore, compared with a structure in which the entire surface of the recording paper S contacts the guide, conveying resistance or frictional charging is suppressed, and compared with the conventional structure of the guide rib extending in the conveying direction, there is no situation in which only specific positions are continuously in contact, thereby suppressing the deviation of the charged state. In addition, the recording paper S is supported by a plurality of wave tops 12 along the conveying direction, and the contact pressure is dispersed compared with the structure of Patent Document 1, thereby suppressing the amount of frictional charging and also suppressing the occurrence of scratches. In particular, in Example 1, the wave tops 12 extend in the width direction rather than the conveying direction, thereby suppressing continuous contact only in specific positions in the width direction. In addition, in Example 1, instead of the entire area in the width direction being the conveying belt 1, the ripple guides 11 are provided on both sides, thereby making it easy to suppress the complexity of the structure and maintain the conveying performance.

[0133] In addition, in the ripple guide 11 of the first embodiment, the height of the middle portion 13 increases as it goes to the downstream side. Therefore, even if the front end of the recording paper S contacts the middle portion 13, it is guided to the wave top 12 by the surface of the middle portion 13. In particular, in thin paper that is easily bent and the front end is easy to droop downward, if the front end hits the surface between the wave tops 12 or hangs on the surface, paper jams or paper wrinkles are likely to occur. In contrast, in the middle portion 13 of the first embodiment, the occurrence of paper jams and the like is suppressed.

[0134] Furthermore, in Example 1, the curved surface 13a of the middle portion 13 is not a planar inclined surface 13b, but a downward convex curved surface 13a. In the planar inclined surface 13b, if the recording paper S is bent, it is easy to contact the middle portion 13 from closer to the wave top 12, and the contact surface with the recording paper S is easy to become larger. Therefore, there is a concern that the conveying resistance or frictional electrification will be aggravated. In contrast, in the downward convex curved surface 13a, the distance from the upper surface of the conveying belt 1 that is roughly consistent with the passing trajectory of the recording paper S is longer than the planar inclined surface 13b, and the recording paper S is not easy to contact the middle portion 13 near the wave top 12. Therefore, the aggravation of the conveying resistance or frictional electrification is suppressed.

[0135] In addition, in Example 1, an introduction guide 16 is provided on the upstream side of the ripple guide 11. In a structure in which the introduction guide 16 is not provided, the front end of the recording paper S first reaches the middle portion 13, and in the case where the front end is prone to droop downward like thin paper, there is a concern that the paper may be jammed. In contrast, in the structure of Example 1 in which the recording paper S from the paper guide SG2 after transfer is first guided by the introduction guide 16, paper jams of the recording paper S are suppressed.

[0136] Furthermore, in Example 1, the height of the wave top 12 is lower than the height of the upper surface of the conveyor belt 1. If the height of the wave top 12 is higher than the upper surface of the conveyor belt 1, the recording paper S adsorbed on the conveyor belt 1 is pressed by the wave top 12 on the outer side in the width direction, and the contact pressure tends to increase. In contrast, in Example 1 in which the height of the wave top 12 is lower than the height of the upper surface of the conveyor belt 1, the increase in contact pressure is suppressed. Therefore, the increase in frictional charge under high contact pressure or the increase in scratches and conveying resistance is suppressed.

[0137] In Embodiment 1, the recording paper S is conveyed with its center portion in the width direction attracted to the conveyor belt 1. Therefore, compared with the configuration described in Patent Document 1 without the conveyor belt 1, the recording paper S with the unfixed image transferred thereto can be conveyed stably.

[0138] Furthermore, in Embodiment 1, the ripple guide 11 is disposed on the outer side of the conveyor belt 1. It is also possible to set the ripple guide 11 in the central portion in the width direction and to set the conveyor belt 1 on both sides of the outer side in the width direction. However, if the conveyor belt 1 is set on both sides, there is a case where a speed difference occurs between the two conveyor belts 1, and the recording paper S is tilted (skewed). In contrast, when the conveyor belt 1 is set in the central portion in the width direction as in Embodiment 1, the recording paper S is less likely to be skewed, and the conveying performance is improved. Therefore, it is desirable to set the conveyor belt 1 in the central portion in the width direction.

[0139] (Variation 1, Variation 2)

[0140] Fig. 7A and Figure 7B is an explanatory diagram of Modification 1 and Modification 2. Fig. 7A is an explanatory diagram of Modification Example 1. Figure 7B This is an explanatory diagram of Modification Example 2.

[0141] In the first embodiment, the curved surface 13a of the middle portion 13 is exemplified as including a convex curved surface facing downward, but the present invention is not limited thereto. Fig. 7A As shown, a structure may be adopted in which the downstream side of the wave top 12 is formed as a vertical surface 21 extending downward in the gravity direction, and a planar inclined surface 22 is formed from the lower end of the vertical surface 21 to the next wave top 12 .

[0142] In addition, if Figure 7B As shown, it can also be set along Figure 6 The shape of the imaginary line 13b.

[0143] (Variation 3-Variation 6)

[0144] Fig. 8A and Figure 8Bis an explanatory diagram of Modification 3 and Modification 4 of Embodiment 1, Fig. 8A is an explanatory diagram of Modification Example 3. Figure 8B This is an explanatory diagram of Modification Example 4.

[0145] In the first embodiment, the structure in which the wave top 12 is extended in the width direction is exemplified, but the present invention is not limited thereto. Fig. 8A , Figure 8B As shown in FIG. 1 , the wave top 31 may be formed by leaving a gap in the width direction. Fig. 8A As shown, the wave tops 31 adjacent to each other in the conveying direction may also be arranged at the same position in the width direction, as shown in FIG. Figure 8B As shown, they can also be arranged at different positions in the width direction. Fig. 8A , Figure 8B In the case of such a configuration, the contact area between the recording paper S and the corrugated top 31 is further reduced compared to the case of the first embodiment, and the frictional charging is further suppressed. Figure 8B In the case of the structure of , the number of times that the contact position of the recording paper S and the corrugated top 31 is the same in the width direction is likely to be reduced, and Fig. 8A Compared with the case of , friction charging is further suppressed.

[0146] Fig.9A and Fig. 9B is an explanatory diagram of Modification 5 and Modification 6 of Embodiment 1, Fig.9A is an explanatory diagram of Modification Example 5. Fig. 9B This is an explanatory diagram of Modification Example 6.

[0147] In addition, if Fig.9A As shown in FIG. 1 , the apex of the wave top 32 may be arranged in a point-like shape instead of being extended in the width direction. That is, the wave top 32 may be arranged with a gap in both the width direction and the conveying direction. Fig.9A By configuring in this way, the contact area is further reduced, thereby suppressing frictional charging.

[0148] Furthermore, if Fig. 9B As shown, the wave top 33 may be inclined relative to the width direction and the conveying direction. In this structure, continuous contact at the same position in the width direction is prevented compared to the guide rib, and friction charging at a specific position is prevented. Fig. 9B In the form of the wave top 33, the wave top 33 is inclined toward the outer side in the width direction as it moves toward the downstream side in the conveying direction. Therefore, the recording paper S that contacts the wave top 33 is subjected to a force that expands toward the outer side in the width direction as it moves toward the downstream side. Therefore, the force that stretches the recording paper S is exerted, which is different from the case without the wave top 33. Fig. 9BCompared with the case of the structure, the generation of wrinkles in the recording paper S is suppressed.

[0149] (Change Example)

[0150] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H06) of the present invention are shown below.

[0151] (H01) In the above embodiment, a copy machine U is illustrated as an example of an image forming apparatus, but the present invention is not limited thereto and may be applied to a FAX or a multifunction machine having multiple functions such as a FAX, a printer, and a copy machine. In addition, the present invention is not limited to a multi-color image forming apparatus and may include a monochrome image forming apparatus, i.e., a so-called black-and-white image forming apparatus.

[0152] (H02) In the above-described embodiments, the specific numbers illustrated can be appropriately changed in accordance with changes in design or specifications. For example, the number and interval of wave tops are not limited to the illustrated forms and can be changed in accordance with the purpose.

[0153] (H03) In the above-described embodiments, the embodiment 1 or the modifications 1 to 6 may be combined with each other. For example, the modification 1 may be combined with the modification 6.

[0154] (H04) In the above-described embodiment, it is desirable to provide the introduction guide 16, but a structure in which the introduction guide 16 is not provided may be adopted.

[0155] (H05) In the above embodiment, the conveyor belt 1 is illustrated as an example of a conveying member, but the present invention is not limited thereto. A roller-shaped conveying member may also be used. In addition, it is desirable to have a structure that attracts the recording paper S, but it may also be a structure that does not have an attracting function.

[0156] (H06) In the above-described embodiment, the height of the wave top is preferably set to be less than the height of the conveyor belt 1, but the present invention is not limited thereto. The height of the wave top may be set to be higher than the conveyor belt 1 within a range in which the contact pressure is allowed.

Claims

1. A medium transport device, characterized in that: include: Transport components, supporting and transporting the medium; as well as The guide member is arranged at a position offset from the conveying member in the width direction of the medium, guides the medium, and has a contact portion that contacts the medium, the contact portion being arranged at a distance relative to the conveying direction of the medium. The middle portion between the contact portions is formed into a slope shape along the conveying direction of the medium, with the height in the gravity direction becoming higher as it goes to the downstream side. The intermediate portion is formed in a convex shape facing downward with respect to the direction of gravity.

2. The medium transport device according to claim 1, characterized in that: The guide member is provided on the outer side in the width direction relative to the conveying member.

3. The medium transport device according to claim 1 or 2, characterized in that: The second guide member is disposed on an upstream side of the guide member along the conveyance direction of the medium, guides the medium, and has a convex strip extending along the conveyance direction of the medium.

4. The medium transport device according to claim 1 or 2, characterized in that: The height of the top of the contact portion is equal to or lower than the height at which the transport member supports the medium.

5. The medium transport device according to claim 1 or 2, characterized in that: The conveying member includes an endless belt-shaped member that supports the medium on a surface and rotates, and an adsorption member that adsorbs the medium toward the belt-shaped member.

6. The medium transport device according to claim 1 or 2, characterized in that: The contact portion includes a convex shape extending in a width direction of the medium.

7. The medium transport device according to claim 6, characterized in that: The contact portion includes a plurality of the convex-shaped contact portions arranged at intervals in the width direction of the medium.

8. The medium transport device according to claim 6, characterized in that: The contact portion includes a convex shape that is inclined toward the downstream side in the conveyance direction as it goes outward in the width direction.

9. The medium transport device according to claim 1 or 2, characterized in that: The contact portion includes a plurality of contact portions that are arranged at intervals with respect to a conveyance direction and a width direction of the medium.

10. An image forming device, characterized in that: include: Like holding parts; a transfer component for transferring the image on the surface of the image holding component to a medium; The medium conveying device according to any one of claims 1 to 9, conveying the medium to which the image is transferred; as well as The fixing device fixes the image on the medium transported by the medium transport device.

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