JP5927132B2 - Sheet conveying apparatus and image forming apparatus provided with the same - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, and an image forming apparatus including the sheet conveying apparatus.

  Conventionally, a technique described in Patent Document 1 is known as a sheet conveying apparatus that conveys a sheet. In the technique, the sheet is conveyed through the sheet conveyance path while the sheet passes through the nip portion between the conveyance roller and the guide roller. The guide roller is supported by the floating shaft together with a movable rib for guiding the sheet. The floating shaft is urged toward the conveying roller by the urging means. Even when the surface of the transport roller is worn or when the diameter of the transport roller changes due to foreign matter adhering to the surface, the pressure of the nip is kept constant by the displacement of the floating shaft. The

JP 2004-345746 A

  In the sheet conveying apparatus described in Patent Document 1, when thick paper is conveyed on the sheet conveying path, the rib marks are likely to remain due to the strong sliding of the movable rib on the surface of the thick paper. In particular, when an image is formed in advance on the surface of the cardboard, there is a problem that a streak-like image defect occurs due to the rubbing.

  The present invention has been made in order to solve the above-described problems, and even when sheets having different thicknesses are conveyed through the sheet conveyance path, it is possible to prevent rib marks from remaining on the sheet surface. It is an object of the present invention to provide a sheet conveying device and an image forming apparatus including the sheet conveying device.

A sheet conveying apparatus according to one aspect of the present invention is disposed in a casing, a sheet conveying path disposed in the casing, in which a sheet is conveyed in a predetermined conveying direction, and opposed to the sheet conveying path, A conveyance roller that conveys the sheet, a guide roller that is disposed to face the conveyance roller across the sheet conveyance path, and forms a nip portion between which the sheet is conveyed, and the sheet conveyance path Is a fixed rib that is arranged on the guide roller side and guides the sheet along the sheet conveyance path, and is arranged at intervals in the sheet width direction intersecting the conveyance direction. and a second fixing rib, wherein disposed on the guide roller side relative to the sheet conveying path, and, facing the first fixing rib and second fixing rib in the sheet width direction, the first It is disposed between the fixing ribs and the second fixing rib, wherein a movable rib of the sheet guides along the sheet conveying path is extended in the seat width direction, and supports the guide rollers and the movable ribs , The floating shaft that can approach and separate from the sheet conveying path, and the movable rib disposed between the first fixed rib and the second fixed rib in the sheet width direction, the first fixed comprising a first biasing means for biasing towards the ribs, and the first fixing rib and second fixing rib is extended toward the sheet conveying path, a slit the floating shaft is inserted An inclined surface that is inclined upward at a predetermined angle toward the movable rib facing the sheet width direction on the side opposite to the sheet conveying path, and the floating shaft is Above A first position in which the dynamic ribs are arranged so as to protrude into the sheet conveying path than the first fixing rib and second fixing rib, the movable rib, before Symbol first fixing rib and second fixing rib the The position of the movable rib can be changed along the slit between a second position that is substantially flush with the sheet conveyance path , and the movable rib is located at the first position of the floating shaft. The first urging means urges the first fixed rib to contact the first fixed rib, and is arranged along the first fixed rib to move the floating shaft from the first position to the second position. Accordingly, an end opposite to the sheet conveying path abuts on the inclined surface of the first fixing rib, and the sheet is resisted against the urging of the first urging means along the inclined surface. Moving in the width direction and being spaced apart from the first fixing rib. Features.

According to this configuration, the floating shaft can be moved toward and away from the sheet conveyance path while supporting the guide roller and the movable rib. The floating shaft has a first position in which the movable rib protrudes from the first fixed rib and the second fixed rib in the sheet conveyance path, and the movable rib , the first fixed rib, and the second fixed rib convey the sheet. The position can be changed between the second position and the second position that are substantially flush with the road. For this reason, it becomes possible to change the number of rib members for guiding the sheet in the sheet conveyance path according to the use conditions.
Further, according to this configuration, even when the first fixed rib, the second fixed rib, and the movable rib are arranged to face each other in the sheet width direction, the first fixed rib and the second fixed rib are formed. A floating shaft supporting the movable rib can move between the first position and the second position along the opening.
Further, according to this configuration, when the floating shaft is disposed at the second position, a gap can be formed between the first fixed rib and the movable rib. As a result, in the sheet width direction, the area where the rib member abuts can be dispersed, and the formation of rib marks can be further suppressed. Further, when the floating shaft is disposed at the first position, the movable rib and the guide roller can be prevented from being separated from the sheet conveyance path.

  In the above configuration, when the first sheet having the first thickness is conveyed to the sheet conveying path, the floating shaft moves to the first position, and the first thickness reaches the sheet conveying path. It is preferable that the floating shaft moves to the second position when a second sheet having a second thickness larger than the second sheet is conveyed.

  According to this configuration, when the first sheet is transported through the sheet transport path, the movable rib guides the first sheet. In addition, when the second sheet is conveyed through the sheet conveyance path, the movable rib and the fixed rib guide the second sheet. For this reason, the contact pressure of each rib is reduced with respect to the 2nd sheet which is thicker than the 1st sheet, and is easy to have a rib mark, and the formation of the rib mark is controlled appropriately.

  In the above configuration, the sheet conveyance path is a conveyance path extending in a lateral direction, the conveyance roller is disposed below the sheet conveyance path, the guide roller is disposed above the sheet conveyance path, and the sheet When the second sheet is transported to the transport path, it is preferable that the floating shaft moves from the first position to the second position by pushing up the guide roller upward. .

  According to this configuration, when the second sheet is conveyed through the sheet conveyance path, the floating shaft is pushed up from the first position to the second position due to the thickness and stiffness of the second sheet. As a result, rib marks on the second sheet can be suppressed with a simple configuration.

  In the above-described configuration, it is preferable that a moving unit that moves the floating shaft from the first position to the second position when the second sheet is conveyed to the sheet conveyance path is preferable.

  According to this configuration, the floating shaft can be moved from the first position to the second position by the moving means.

  In the above-described configuration, it is desirable to have second urging means for urging the floating shaft from the second position toward the first position.

  According to this configuration, when the floating shaft is disposed at the first position, the movable rib and the guide roller can be prevented from being separated from the sheet conveyance path.

  An image forming apparatus according to another aspect of the present invention includes an image forming unit that forms an image on a sheet, and transports the sheet toward the image forming unit or transports the sheet on which the image is formed. And a sheet conveying apparatus according to claim 1.

  According to this configuration, it is possible to change the number of rib members for guiding the sheet conveyed in the sheet conveyance path according to the use conditions. For this reason, the formation of rib marks on the sheet conveyed to the image forming unit is suppressed. Further, rib marks are formed on the sheet on which the toner image is formed in the image forming unit, and image quality defects are prevented from occurring in the toner image.

  According to the present invention, even when sheets having different thicknesses are conveyed on the sheet conveying path, a sheet conveying apparatus that suppresses rib marks from remaining on the sheet surface and an image forming apparatus including the sheet conveying apparatus are provided. Is done.

1 is a schematic front view illustrating a structure of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing of the sheet conveying apparatus which concerns on one Embodiment of this invention. It is a sectional side view of the sheet conveying apparatus which concerns on one Embodiment of this invention. FIG. 4 is an enlarged view around a floating shaft arranged at a first position in the sheet conveying apparatus according to the embodiment of the present invention. FIG. 5 is an enlarged view of the vicinity of a floating shaft arranged at a second position in the sheet conveying apparatus according to the embodiment of the present invention. It is a sectional side view of the sheet conveying apparatus which concerns on one Embodiment of this invention. In the sheet conveying apparatus which concerns on other embodiment of this invention, it is an enlarged view of a floating shaft periphery.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic front view showing the internal structure of an image forming apparatus 1 according to an embodiment of the present invention by broken lines. Here, a printer is exemplified as the image forming apparatus 1, but the image forming apparatus may be a multifunction machine, a copier, a facsimile machine, or the like.

  <Description of Image Forming Apparatus>

  The image forming apparatus 1 includes an apparatus body 10 having a substantially rectangular parallelepiped housing structure. The apparatus main body 10 is a housing having a substantially rectangular parallelepiped shape. The image forming apparatus 1 includes an image forming unit 11, a fixing unit 12, a paper feed tray 13, a sheet conveyance path 14, and a paper discharge unit 15.

  The image forming unit 11 performs a process of generating a toner image and transferring it onto a sheet based on a known electrophotographic method. In other embodiments, other image forming methods such as an ink jet method may be employed.

  The image forming unit 11 includes a photosensitive drum (not shown) and a charger, an exposure device, a developing device, a cleaning device, and the like (not shown) arranged around the photosensitive drum.

  The photosensitive drum rotates about its axis, and an electrostatic latent image and a toner image are formed on its peripheral surface. As the photosensitive drum, a photosensitive drum using an amorphous silicon (a-Si) material can be used. The charger uniformly charges the surface of the photosensitive drum. The exposure device includes a laser light source and optical devices such as a mirror and a lens, and forms an electrostatic latent image by irradiating the peripheral surface of the photosensitive drum with light based on image data of the original image. The developing device supplies toner to the peripheral surface of the photosensitive drum in order to develop the electrostatic latent image formed on the photosensitive drum. The developing device is for a two-component developer and includes a screw feeder, a magnetic roller, and a developing roller. The cleaning device includes a cleaning roller and cleans the peripheral surface of the photosensitive drum after the toner image is transferred.

  A transfer roller (not shown) (not shown) is disposed facing the photosensitive drum. The toner image on the photosensitive drum is transferred to the sheet at the transfer nip portion between the photosensitive drum and the transfer roller. A secondary transfer bias potential having a polarity opposite to that of the toner image is applied to the transfer roller.

  The fixing unit 12 performs a fixing process for fixing the toner image on the sheet. A pressure roller is pressed against a fixing roller (not shown) to form a fixing nip portion. As the sheet passes through the fixing nip portion, the toner image transferred to the sheet is fixed to the sheet.

  The sheet feed tray 13 protrudes from the right wall portion of the apparatus main body. The sheet placed on the paper feed tray 13 is fed toward the image forming unit 11 by a paper feed roller (not shown).

  The sheet conveyance path 14 is a conveyance path that is disposed inside the apparatus main body 10 and conveys a sheet in a predetermined conveyance direction. The sheet conveyance path 14 is a conveyance path that extends from the paper feed tray 13 through the image forming unit 11 and the fixing unit 12 to the paper discharge unit 15. In particular, in the present embodiment, the conveyance direction of the sheet carried out from the fixing unit 12 is changed from a horizontal direction (a direction from right to left) to a vertical direction (a direction from bottom to top). The paper discharge unit 15 is disposed on the upper surface of the apparatus main body 10.

<Description of sheet conveying device>
Next, the sheet conveying apparatus 20 according to the present embodiment will be described in detail with reference to FIGS. 2 to 5. FIG. 2 is a cross-sectional view of the sheet conveying apparatus 20 according to the present embodiment. FIG. 3 is a side sectional view of the sheet conveying apparatus 20 according to the present embodiment. FIG. 4 is an enlarged view of the periphery of the floating shaft 42 disposed at the first position in the sheet conveying apparatus 20. FIG. 5 is an enlarged view of the periphery of the floating shaft 42 arranged at the second position in the sheet conveying apparatus 20.

  As illustrated in FIG. 2, the sheet conveying device 20 is disposed in an area where the sheet conveying path 14 curves from the horizontal direction to the vertical direction, and conveys the sheet along the sheet conveying path 14. The sheet conveying device 20 includes a support member 21. The support member 21 is a housing portion that supports each component of the sheet conveying apparatus 20 and is disposed so as to extend in the sheet width direction (the depth direction of the paper surface of FIG. 2). Further, the sheet conveying apparatus 20 includes a conveying roller 30, a guide roller 40, a first upper fixing rib 22 (fixing rib), a second upper fixing rib 23, a first lower fixing rib 24, and a second lower fixing. A rib 25, a gap 26, and a guide plate 27 are provided.

  The conveyance roller 30 is disposed to face the sheet conveyance path 14 and conveys the sheet in the conveyance direction. The transport roller 30 includes a shaft 31 and an elastic roller 32. The shaft 31 serves as a rotation axis of the transport roller 30. The elastic roller 32 is a roller member disposed around the shaft 31. The peripheral surface of the elastic roller 32 contacts the sheet. The transport roller 30 is rotationally driven by a driving unit (not shown). In the present embodiment, the sheet conveying path 14 extends in the lateral direction at the position where the conveying rollers 30 face each other, and the conveying roller 30 is disposed below the sheet conveying path 14.

  The guide roller 40 is disposed to face the conveyance roller 30 with the sheet conveyance path 14 interposed therebetween. The guide roller 40 forms a nip portion where the sheet is conveyed with the conveying roller 30. The guide roller 40 abuts on the circumferential surface or the sheet of the transport roller 30 and rotates following these. In the present embodiment, the guide roller 40 is disposed above the sheet conveyance path 14.

  The first upper fixing rib 22 and the second upper fixing rib 23 are arranged on the guide roller 40 side with respect to the sheet conveyance path 14 and guide the sheet along the sheet conveyance path 14. The first upper fixing rib 22 is disposed downstream of the guide roller 40 in the sheet conveying direction. The second upper fixing rib 23 is disposed on the upstream side of the guide roller 40 in the sheet conveying direction.

  The first lower fixing rib 24 and the second lower fixing rib 25 are arranged on the conveying roller 30 side with respect to the sheet conveying path 14 and guide the sheet along the sheet conveying path 14. The first lower fixing rib 24 is disposed on the downstream side in the sheet conveying direction from the conveying roller 30. Further, the second lower fixing rib 25 is disposed on the upstream side in the sheet conveying direction from the conveying roller 30.

  The first upper fixing rib 22, the second upper fixing rib 23, the first lower fixing rib 24, and the second lower fixing rib 25 extend along the sheet conveying path 14 and intersect the sheet conveying direction. A plurality are arranged at intervals in the width direction. At this time, the first upper fixing rib 22 and the first lower fixing rib 24 and the second upper fixing rib 23 and the second lower fixing rib 25 are arranged to face each other with the sheet conveyance path 14 interposed therebetween. As shown in FIG. 2, there is a gap 26 between the first upper fixing rib 22 and the first lower fixing rib 24 and between the second upper fixing rib 23 and the second lower fixing rib 25. It is formed. A part of the sheet conveying path 14 is formed by the gap 26. The guide plate 27 is disposed in the sheet conveyance path 14 on the downstream side of the conveyance roller 30 in the sheet conveyance direction. The guide plate 27 guides the sheet conveyed by the conveyance roller 30 to be conveyed upward along the sheet conveyance path 14.

  Referring to FIG. 4, the first upper fixing rib 22 includes an inclined surface 22H. The inclined surface 22H is an inclined surface that is inclined at a predetermined angle with respect to the sheet width direction on the opposite side of the first upper fixing rib 22 from the sheet conveyance path 14. The inclined surface 22H is inclined from the first upper fixed rib 22 so as to approach a movable rib 41 described later.

  Further, the sheet conveying apparatus 20 includes a movable rib 41, a floating shaft 42, a shaft biasing spring 50, and a rib biasing spring 51.

  The movable rib 41 is disposed on the guide roller 40 side with respect to the sheet conveyance path 14. The movable rib 41 is disposed to face the first upper fixed rib 22 in the sheet width direction, and guides the sheet along the sheet conveyance path 14. Referring to FIG. 3, the movable rib 41 is disposed between the adjacent first upper fixed ribs 22. The movable rib 41 is supported by the floating shaft 42. In the present embodiment, as shown in FIG. 3, two movable ribs 41 are connected to the floating shaft 42. In other embodiments, the number of movable ribs 41 may be one, or three or more. Further, the plurality of movable ribs 41 may be supported by different shaft members.

  The floating shaft 42 extends in the sheet width direction and supports the guide roller 40 and the movable rib 41. Further, the floating shaft 42 can be moved toward and away from the sheet conveying path 14 in the vertical direction. In the present embodiment, the floating shaft 42 extends through the plurality of first upper fixing ribs 22 in the seat width direction. At this time, the floating shaft 42 is inserted into a long-hole-shaped guide groove 43 (slit) that extends toward the sheet conveyance path 14 in the first upper fixing rib 22. The floating shaft 42 fixedly supports the plurality of movable ribs 41. The floating shaft 42 supports the guide roller 40 so as to be rotatable. For this reason, a bearing member (not shown) is interposed between the floating shaft 42 and the guide roller 40. With the floating shaft 42 integrally supporting the guide roller 40 and the movable rib 41, the floating shaft 42 approaches or separates from the sheet conveying path 14 along the guide groove 43.

  Specifically, as the floating shaft 42 moves along the guide groove 43, the position can be changed between the first position (FIGS. 2 and 4) and the second position (FIGS. 5 and 6). Is done. In the first position shown in FIG. 2, the movable rib 41 is disposed so as to protrude from the first upper fixed rib 22 into the sheet conveyance path 14. Further, at the second position shown in FIG. 5, the movable rib 41 and the first upper fixed rib 22 are disposed substantially flush with the sheet conveying path 14. For this reason, it is possible to change the number of rib members for guiding the sheet conveyed through the sheet conveyance path 14 according to the use conditions of the image forming apparatus 1.

  The shaft biasing spring 50 (FIG. 3) (second biasing means) biases the floating shaft 42 from the second position toward the first position. In other words, the shaft biasing spring 50 biases the floating shaft 42 so that the guide roller 40 abuts on the transport roller 30.

  The rib urging spring 51 (FIG. 4) (first urging means) includes a movable rib 41 arranged between the adjacent first upper fixing ribs 22 in the sheet width direction, and a front first upper fixing rib. Energize towards 22. As shown in FIG. 4, at the first position of the floating shaft 42, the movable rib 41 is disposed along the first upper fixed rib 22 on the front side by the biasing force of the rib biasing spring 51. On the other hand, in the second position of the floating shaft 42 shown in FIG. 5, the movable rib 41 resists the urging force of the rib urging spring 51 from the first upper fixed rib 22 on the front side in the seat width direction. Moved away.

  Next, with reference to FIG. 6 in addition to FIGS. 1 to 5, the operation of the sheet conveying apparatus 20 according to the present embodiment will be described. FIG. 6 is a side sectional view of the sheet conveying apparatus 20 according to the present embodiment, and shows a state where the floating shaft 42 is disposed at the second position. On the other hand, FIG. 2 described above shows a side sectional view of the sheet conveying apparatus 20 in a state in which the floating shaft 42 is disposed at the first position. As described above, in the present embodiment, the sheet conveying apparatus 20 is disposed in an area where the sheet conveying path 14 is curved. In such a region, the sheet is easily rubbed strongly against the rib member that guides the sheet, and rib marks are easily formed.

  When thin paper or plain paper (first sheet) having the first thickness is placed on the sheet feed tray 13 and the sheet is conveyed through the sheet conveyance path 14, the floating shaft 42 is moved to the state shown in FIGS. Arranged (moves) in the first position shown. At this time, the movable rib 41 is disposed above the sheet conveying path 14 so as to protrude from the first upper fixed rib 22 into the sheet conveying path 14. For this reason, the sheet conveyed on the sheet conveyance path 14 by the conveyance roller 30 and the guide roller 40 is conveyed toward the downstream side in the conveyance direction while being mainly guided by the movable rib 41. At this time, as shown in FIG. 4, the one movable rib 41 is arranged along the opposing first upper fixed rib 22 by the biasing force of the rib biasing spring 51.

  On the other hand, when a thick sheet (second sheet) having a second thickness larger than the first thickness is placed on the sheet feeding tray 13 and the sheet is conveyed through the sheet conveyance path 14, the thickness of the sheet is increased. As a result, the guide roller 40 is pushed upward. As a result, the floating shaft 42 that supports the guide roller 40 and the movable rib 41 is moved upward along the guide groove 43 and moved to the second position (FIGS. 5 and 6). At this time, as changed from FIG. 4 to FIG. 5, the front movable rib 41 moves in the sheet width direction (rear direction) along the inclined surface 22H of the first upper fixed rib 22 facing the front rib. Move upward. As a result, the guide roller 40 is separated from the transport roller 30. Further, the rear movable rib 41 coupled to the front movable rib 41 via the floating shaft 42 also moves upward while moving in the sheet width direction.

  At the second position of the floating shaft 42, the movable rib 41 and the first upper fixed rib 22 are disposed substantially flush with the sheet conveyance path 14 above the sheet conveyance path 14. Therefore, the sheet conveyed through the sheet conveyance path 14 by the conveyance roller 30 and the guide roller 40 is conveyed toward the downstream side in the conveyance direction while being guided by the movable rib 41 and the first upper fixed rib 22.

  In other words, as compared with the case where the floating shaft 42 is disposed at the first position, the number of rib members for guiding the sheet is increased, and the pressure applied by the individual rib members to the sheet is reduced. For this reason, even if it is a strong paper and it is easy to make a rib mark by contact | abutting to a rib member, it is suppressed suitably that a rib mark is attached. Further, even when the toner image is formed on the sheet surface after passing through the image forming unit 11 and the fixing unit 12 as in the present embodiment, the image has a streak-like image defect. Occurrence is suppressed.

  In the present embodiment, as described above, when the floating shaft 42 is disposed at the second position, a gap is formed between the first upper fixed rib 22 and the movable rib 41 in the seat width direction. (FIG. 5). As a result, in the sheet width direction, the area where the rib member abuts on the sheet can be dispersed, and the formation of rib marks can be further suppressed.

  In the present embodiment, when the second sheet is unloaded from the sheet conveying apparatus 20, the floating shaft 42 is again moved along the guide groove 43 by the weight of the floating shaft 42 including the guide roller 40 and the movable rib 41. Moved to position 1. As described above, in the present embodiment, the position of the floating shaft 42 can be changed by the thickness of the second sheet and the weight of the floating shaft 42. Therefore, the number of rib members that contact the sheet can be changed with a simple configuration. Realized.

  Further, in the above embodiment, even when the first upper fixed rib 22 and the movable rib 41 are arranged to face each other in the sheet width direction, the guide groove 43 formed in the first upper fixed rib 22 Along the way, the floating shaft 42 supporting the movable rib 41 can move between the first position and the second position. Further, when the floating shaft 42 is disposed at the first position, the floating shaft 42 receives the urging force of the shaft urging spring 50 and the rib urging spring 51, so that the movable rib 42 and the guide roller 40 are in contact with the sheet conveying path 14. It is suppressed that it is separated from (leaps up) from.

  Next, a sheet conveying apparatus 20A according to the second embodiment of the present invention will be described. FIG. 7 is an enlarged view of the periphery of the floating shaft 42A. In this embodiment, compared with the first embodiment described above, the floating shaft 42A is different in the manner of movement from the first position to the second position. Therefore, the difference will be described, and other points will be described. Description is omitted.

  In the present embodiment, the sheet conveying apparatus 20 </ b> A includes a cam 52 (moving unit) and a motor 53. The cam 52 contacts the floating shaft 42A from below on one end side of the floating shaft 42A. In the present embodiment, the cam 52 moves the floating shaft 42A from the first position to the second position when the second sheet is conveyed to the sheet conveyance path. The motor 53 generates a driving force that rotates the cam 52.

  When the first sheet is conveyed to the sheet conveying apparatus 20A, the cam 52 is disposed at a position shown in FIG. 7 by a control unit (not shown) provided in the image forming apparatus 1. As a result, the floating shaft 42A is disposed at the first position, and the first sheet is guided along the sheet conveying direction by the movable rib 41A.

  On the other hand, when the second sheet is conveyed to the sheet conveying apparatus 20A, the motor 53 rotates the cam 52 by 180 degrees from the state of FIG. 7 as controlled by the control unit. As a result, the cam 52 moves the floating shaft 42A upward. At this time, similarly to the first embodiment, the movable rib 41A moves upward along the inclined surface 22HA of the first upper fixed rib 22A while moving in the sheet width direction (front-rear direction). As a result, the floating sheet 42A is disposed at the second position, and the second upper sheet 22A and the movable rib 41A, which are substantially flush with the sheet conveyance path, cause the second sheet to move along the sheet conveyance direction. Guided. Therefore, the number of rib members that guide the second sheet is increased, and the pressure that each rib member applies to the second sheet is reduced.

  The sheet conveying apparatuses 20 and 20A and the image forming apparatus 1 including the sheet conveying apparatuses 20 and 20A according to the embodiment of the present invention have been described above. However, the present invention is not limited to this, and for example, the following modified embodiment is provided. Can be adopted.

  (1) In the above embodiment, when the first sheet having the first thickness is conveyed to the sheet conveying path 14, the floating shaft 42 is disposed at the first position and is thicker than the first thickness. Although the embodiment has been described in which the floating shaft 42 is disposed at the second position when the second sheet is conveyed to the sheet conveyance path 14, the present invention is not limited to this. Not only the thickness of the sheet, but also a mode in which the floating shaft 42 is arranged at the first position and the second position depending on the strain, surface property, material, and the like of the sheet.

  (2) In the above embodiment, the sheet conveying device 20 has been described as being disposed on the downstream side in the sheet conveying direction with respect to the image forming unit 11 and the fixing unit 12, but the present invention is limited to this. is not. The sheet conveying device 20 may be applied to other areas where the sheet is conveyed.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Apparatus main body 11 Image forming part 12 Fixing part 13 Paper feed tray 14 Sheet conveyance path 15 Paper discharge part 20 Sheet conveying apparatus 21 Support member 22 First upper fixed rib (fixed rib)
22H inclined surface 23 second upper fixed rib 24 first lower fixed rib 25 second lower fixed rib 26 gap 27 guide plate 30 transport roller 31 shaft 32 elastic roller 40 guide roller 41 movable rib 42 floating shaft 43 guide groove (slit)
50 Shaft biasing spring (second biasing means)
51 Rib biasing spring (first biasing means)
52 Cam (moving means)
53 motor

Claims (6)

A housing,
A sheet conveyance path disposed in the housing and conveying a sheet in a predetermined conveyance direction;
A conveying roller disposed opposite to the sheet conveying path and conveying the sheet;
A guide roller that is disposed opposite the conveyance roller across the sheet conveyance path, and forms a nip portion between which the sheet is conveyed.
A fixed rib that is disposed on the guide roller side with respect to the sheet conveyance path and guides the sheet along the sheet conveyance path, and is disposed at an interval in the sheet width direction that intersects the conveyance direction. A first fixing rib and a second fixing rib ;
Wherein disposed on the guide roller side relative to the sheet conveying path, and said facing in the sheet width direction in the first fixing rib and second fixing rib, and the second fixing rib and the first fixing rib A movable rib disposed between and guiding the sheet along the sheet conveyance path;
A floating shaft that extends in the sheet width direction, supports the guide roller and the movable rib, and can approach and separate from the sheet conveyance path;
Wherein in the sheet width direction, and a first biasing means for biasing toward the placed the movable rib, the first fixing rib between the first fixing rib and second fixing rib,
The first fixed rib and the second fixed rib are extended toward the sheet conveying path, and the slit through which the floating shaft is inserted and on the side opposite to the sheet conveying path, with respect to the sheet width direction An inclined surface that is inclined upward at a predetermined angle toward the opposed movable rib,
Said floating shaft has a first position in which said movable ribs are arranged to protrude into the sheet conveying path than the first fixing rib and second fixing rib, the movable rib, before Symbol first fixing rib and the Between the second position where the second fixed rib is disposed substantially flush with the sheet conveyance path , the position can be changed along the slit .
The movable rib is disposed along the first fixed rib in contact with the first fixed rib by the biasing of the first biasing means at the first position of the floating shaft. Along with the movement from the first position to the second position, the end opposite to the sheet conveying path comes into contact with the inclined surface of the first fixing rib, and along the inclined surface, The sheet conveying apparatus is arranged to move in the sheet width direction against the urging force of the first urging unit and to be separated from the first fixing rib .   When the first sheet having the first thickness is conveyed to the sheet conveying path, the floating shaft moves to the first position, and the second thicker than the first thickness is moved to the sheet conveying path. 2. The sheet conveying apparatus according to claim 1, wherein when the second sheet having a thickness of 1 mm is conveyed, the floating shaft moves to the second position. The sheet conveyance path is a conveyance path extending in a lateral direction,
The transport roller is disposed below the sheet transport path, and the guide roller is disposed above the sheet transport path,
When the second sheet is conveyed to the sheet conveyance path, the floating sheet moves from the first position to the second position by the second sheet pushing up the guide roller upward. The sheet conveying apparatus according to claim 2.   The sheet according to claim 2, further comprising a moving unit that moves the floating shaft from the first position to the second position when the second sheet is conveyed to the sheet conveyance path. Conveying device. 5. The sheet conveying apparatus according to claim 1 , further comprising a second urging unit that urges the floating shaft from the second position toward the first position . 6. An image forming unit for forming an image on a sheet;
The sheet conveying apparatus according to claim 1, wherein the sheet is conveyed toward the image forming unit, or the sheet on which the image is formed is conveyed,
An image forming apparatus comprising:

Images