Sheet carrier and image forming apparatus

Abstract

To provide a sheet carrier allowed to execute jam processing by a simple construction.SOLUTION: A sheet carrier comprises: a transport roller that has a rotary shaft and a sheet-carrying portion to rotate in a first rotating direction; a ratchet part that is provided on the rotary shaft between one end of the rotary shaft and the sheet-carrying portion so as to rotate with the rotary shaft and has a first projection portion projecting toward one end of the rotary shaft; a lever that has a main-body portion, a grip portion extending from the main-body portion in a manner being orthogonal to the main-body portion and a second projection portion projecting from the main-body portion toward the ratchet part and is provided to move axially and circumferentially of the rotary shaft on a side of the rotary shaft closer to one end than the ratchet part; a first biasing part that provides the lever with a first biasing force acting axially toward the ratchet part from the one end of the rotary shaft; and a second biasing part that provides the lever with a second biasing force to rotate the lever in a second rotating direction opposite to the first rotating direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In a sheet conveying device that conveys a sheet, the sheet may become jammed for some reason during conveyance. When such a jam occurs, the jammed sheet must be removed, or so-called jam clearance must be performed. In order to easily clear such a jam, a sheet conveying device that conveys a sheet sandwiched between a pair of registration rollers by operating a lever has been disclosed (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-70117 Summary of the Invention [Problem to be solved by the invention]

[0004] In the sheet conveying device disclosed in Patent Document 1, the pair of registration rollers is composed of a registration drive roller and a registration driven roller, and a lever is attached to the registration drive roller shaft. A one-way clutch that transmits rotational force only in one direction is provided between the registration drive roller shaft and the lever, and the sheet can be conveyed by rotating the lever in one direction. However, one-way clutches have a complex internal structure and are expensive. Furthermore, if the contact portion of the registration drive roller shaft with the one-way clutch is worn down by the load during rotation, slippage may occur, causing sheet conveyance problems. Therefore, it is desirable to use expensive stainless steel for the registration drive roller shaft, which is resistant to wear, which may increase the cost of the sheet conveying device.

[0005] An object of the present disclosure is to provide a sheet conveying device and an image forming apparatus that can perform jam clearance with a simple configuration. [Means for solving the problem]

[0006] A sheet conveying device according to one aspect of the present disclosure includes a conveying roller having a rotating shaft and a sheet conveying section provided on the other end side of one end of the rotating shaft and in contact with a sheet, the conveying roller rotating in a first rotation direction when conveying the sheet; a ratchet section provided between one end of the rotating shaft and the sheet conveying section so as to rotate together with the rotating shaft and having a first protrusion protruding toward the one end side of the rotating shaft; a main section provided with an insertion hole through which the rotating shaft is inserted; a grip section extending from the main section perpendicular to the rotating shaft; and a lever provided on the one end side of the rotating shaft from the ratchet section so as to be movable in the axial and circumferential directions of the rotating shaft. the lever is provided with a first biasing portion that applies a first biasing force to the lever, the first biasing force acting from one end of the rotating shaft toward the ratchet portion along the axial direction, and a second biasing portion that applies a second biasing force to the lever to rotate the lever in a second rotational direction opposite to the first rotational direction, wherein the lever is in a spaced position where the second protrusion is spaced from the first protrusion due to the second biasing force, and when the lever is rotated in the first rotational direction against the second biasing force, the first biasing force moves the second protrusion from the spaced position to an engaged position where it engages with the first protrusion, and when the lever is further rotated in the first rotational direction at the engaged position, the conveying roller rotates in the first rotational direction via the ratchet portion.

[0007] An image forming apparatus according to one aspect of the present disclosure includes a rotating shaft, a conveying roller provided on the other side of one end of the rotating shaft and having a sheet conveying section that contacts a sheet and rotates in a first rotation direction when conveying the sheet, a ratchet section provided between one end of the rotating shaft and the sheet conveying section so as to rotate together with the rotating shaft and having a first protrusion that protrudes toward the one end of the rotating shaft, a main body section provided with an insertion hole through which the rotating shaft is inserted, a grip section extending from the main body section perpendicular to the rotating shaft, and a second protrusion that protrudes from the main body section toward the ratchet section, and a lever provided on the one end side of the rotating shaft from the ratchet section so as to be movable in the axial and circumferential directions of the rotating shaft, and and a second biasing portion that applies a second biasing force to the lever to rotate the lever in a second rotation direction opposite to the first rotation direction, wherein the lever is in a spaced position where the second protrusion is spaced from the first protrusion due to the second biasing force, and when the lever is rotated in the first rotation direction against the second biasing force, the first biasing force causes the second protrusion to move from the spaced position to an engaged position where the second protrusion engages with the first protrusion, and when the lever is at the engaged position, the conveying roller rotates in the first rotation direction via the ratchet portion when the lever is further rotated in the first rotation direction. [Effects of the Invention]

[0008] According to the present disclosure, the sheet conveying device and the image forming apparatus have an advantage that they can perform jam clearance with a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view illustrating an example of an internal structure of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] 1 is a perspective view illustrating an example of a configuration of a sheet conveying device according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is an exploded perspective view of the sheet conveying device shown in FIG. [Figure 4] FIG. 3 is a cross-sectional view of the sheet conveying device shown in FIG. [Figure 5] FIG. 2 is a perspective view illustrating an example of a configuration of a ratchet portion according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a side view of the ratchet portion shown in FIG. 5. [Figure 7] FIG. 2 is a plan view illustrating an example of a lever portion according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a side view of the lever shown in FIG. 7. [Figure 9] FIG. 1 is a perspective view illustrating an example of a roller holder according to an embodiment of the present disclosure. [Figure 10] 10 is an enlarged view of a portion B of the roller holder shown in FIG. [Figure 11] 1 is a cross-sectional view of the sheet conveying device shown in FIG. 2 taken along the line XI-XI. [Figure 12] 10 is a rear view of the operating part when the lever teeth portion and the ratchet teeth portion are in a separated position. FIG. [Figure 13] 12 is a cross-sectional view showing an example of the cross-sectional structure of the operation section shown in FIG. 11. [Figure 14] 10 is a rear view of the operating part when the lever teeth and the ratchet teeth are in an engagement position. FIG. [Figure 15] 15 is a cross-sectional view showing an example of the cross-sectional structure of the operation section shown in FIG. 14. [Figure 16] 10 is a rear view of the operating portion when the lever teeth and the ratchet teeth are in the engagement position and the guide protrusion has moved to its end. FIG. [Figure 17] 17 is a cross-sectional view showing an example of the cross-sectional structure of the operation section shown in FIG. 16. [Figure 18] 1 is a cross-sectional view of the sheet conveying device shown in FIG. 2 taken along the line XI-XI. [Figure 19] 19 is a cross-sectional view showing an example of the cross-sectional structure of the operation section shown in FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments and modifications of the present disclosure will be described with reference to the drawings. Note that, hereinafter, identical or corresponding components will be designated by the same reference numerals throughout the drawings, and redundant descriptions thereof will be omitted. Furthermore, the embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. Various modifications other than these embodiments and modifications are possible depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure.

[0011] (Image forming device) An image forming apparatus 100 according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a side view showing an example of the internal structure of the image forming apparatus 100 according to an embodiment of the present disclosure.

[0012] As shown in FIG. 1, the image forming apparatus 100 includes an image forming section 110, an image reading device 90, a document placing table 91, and an automatic document processing device 120.

[0013] The image forming section 110 includes a charger 1 , an exposure unit 2 , a developing unit 3 , a photosensitive drum 4 , a toner cartridge 5 , a transfer roller 6 , a fixing unit 7 , and a paper feed cassette 8 .

[0014] The charger 1 uniformly charges the surface of the photosensitive drum 4 to a predetermined potential.

[0015] The exposure unit 2 is a laser scanning unit (LSU) equipped with a laser emission section, a reflecting mirror, etc. Therefore, the exposure unit 2 is equipped with a polygon mirror that scans the laser beam, and optical members such as a lens or mirror that guide the laser light reflected by the polygon mirror to the photosensitive drum 4. The exposure unit 2 exposes the photosensitive drum 4, which has been charged by the charger 1, in accordance with image data, thereby forming an electrostatic latent image on the surface of the photosensitive drum 4 in accordance with the image data.

[0016] The developing unit 3 supplies the toner contained therein to the electrostatic latent image formed on the surface of the photosensitive drum 4, thereby forming a toner image on the surface of the photosensitive drum 4.

[0017] The transfer roller 6 is disposed so as to abut against the photosensitive drum 4 and rotate together with the photosensitive drum 4. When the sheet 30 is nipped and conveyed at the transfer nip Nt, which is the abutment portion with the photosensitive drum 4, the toner image formed on the surface of the photosensitive drum 4 is transferred to the sheet 30. A voltage is applied to the transfer roller 6 to electrostatically transfer the toner image to the sheet 30.

[0018] The fixing unit 7 includes a heat roller 7a and a pressure roller 7b, each having a heat source inside, that are arranged to rotate in contact with each other, and the heat roller 7a and the pressure roller 7b are configured to sandwich and transport the sheet 30 at a fixing nip Nf, which is the contact portion. The heat roller 7a is controlled to a predetermined fixing temperature based on a signal from a temperature detector (not shown), and the toner image transferred to the sheet 30 is melted by heat and fixed to the sheet 30 by applying pressure between the heat roller 7a and the pressure roller 7b.

[0019] The paper feed cassette 8 is a tray for storing sheets 30 used in image formation. The image forming unit 110 is provided with a sheet transport path 9 for sending the sheets 30 in the paper feed cassette 8 to a paper discharge tray 10 via a transfer nip portion Nt and a fixing nip portion Nf. On the sheet transport path 9, a pickup roller 11, a plurality of sheet transport rollers 12, a registration roller 13, a transfer roller 6, a fixing unit 7, etc. are arranged between the paper feed cassette 8 and the paper discharge tray 10.

[0020] The pickup roller 11 is provided near the end of the paper feed cassette 8, and picks up the sheets 30 one by one from the paper feed cassette 8 and supplies them to the sheet transport path 9.

[0021] The sheet conveying roller 12 is a member for assisting in conveying the sheet 30, and is configured by a pair of rollers. A plurality of the sheet conveying rollers 12 are provided along the sheet conveying path 9.

[0022] The registration rollers 13 are members that temporarily hold the sheet 30 being conveyed in the sheet conveying path 9, and are composed of a pair of rollers (first roller 13a and second roller 13b). Of the pair of rollers, the rotation shaft 13a1 (see FIG. 2 described later) of the first roller 13a is a drive shaft that rotates in one direction when a driving force is transmitted from a drive motor (not shown), and the rotation shaft of the second roller 13b is a driven shaft that rotates by the rotation of the rotation shaft 13a1 of the first roller 13a. The registration rollers 13 convey the sheet to a contact position between the photosensitive drum 4 and the transfer roller 6 at a timing that aligns the leading edge of the toner image on the photosensitive drum 4 with the leading edge of the sheet 30.

[0023] The toner image is transferred from the photosensitive drum 4 to the sheet 30 conveyed from the registration roller 13 at the transfer nip Nf, and the toner image is fixed to the sheet at the fixing nip Tf provided downstream of the transfer roller 6 in the sheet conveyance direction. Then, the sheet 30 with the fixed toner image is sent to the paper discharge tray 10.

[0024] Additionally, an image reading device 90 and an original placement table 91 made of transparent glass are provided above the image forming unit 110. Additionally, an automatic original processing device 120 is attached above the original placement table 91. The automatic original processing device 120 automatically transports an original onto the original placement table 91. Additionally, by rotating the automatic original processing device 120 upward to open the top of the original placement table 91, an original can also be placed directly on the original placement table 91.

[0025] The image reading device 90 reads image data from a document that is transported or placed on a document placing table 91. The image forming unit 110 prints an image on a sheet 30 based on the image data read by the image reading device 90.

[0026] The image forming apparatus 100 having the above-described configuration may experience a paper jam in which the sheet 30 being fed through the sheet conveying path 9 stops and gets stuck for some reason. When such a paper jam occurs, the user must open a side wall door or the like of the housing of the image forming apparatus 100 and perform jam clearance to remove the sheet 30 from the sheet conveying path 9. In particular, if a subsequent sheet 30 is waiting at the registration rollers 13, it must be removed.

[0027] The registration roller 13 can rotate in only one direction (sheet conveying direction D), but when a paper jam occurs, if the leading edge of the sheet 30 sandwiched between the first roller 13a and the second roller 13b of the registration roller 13 is stopped without protruding from the registration roller 13 toward the transfer nip portion Nt, the user cannot grasp the leading edge of the sheet 30 that has protruded from the registration roller 13 and pull it out to remove it.

[0028] Therefore, the image forming apparatus 100 according to this embodiment is configured with a sheet conveying device 200 in which a lever 22 is provided at one end of the first roller 13a of the registration roller 13, and the user can push down the gripping portion 22a of the lever 22 (see Figure 2 described below) to send the sheet 30 downstream from the registration roller 13 in the sheet conveying direction D.

[0029] (sheet conveying device) The configuration of the sheet conveying device 200 will be described below with reference to FIGS.

[0030] Fig. 2 is a perspective view showing an example of a configuration of a sheet conveying device 200 according to an embodiment of the present disclosure. Fig. 3 is an exploded perspective view of the sheet conveying device 200 shown in Fig. 2. Fig. 4 is a cross-sectional view of the sheet conveying device 200 shown in Fig. 2. Fig. 4 shows the cross-sectional structure of part A in the sheet conveying device 200 shown in Fig. 2 when viewed from the side.

[0031] The sheet conveying device 200 of the present disclosure is configured to include a registration roller 13 (first roller 13a and second roller 13b), an operating unit 20 provided on the registration roller 13, and a roller holder 14 that supports the first roller 13a (conveying roller) and second roller 13b of the registration roller 13, respectively.

[0032] 2, a pair of first roller 13a and second roller 13b (not shown in FIG. 2) included in the registration roller 13 is supported by a roller holder 14 so as to be rotatable in one direction (rotation direction R). Then, a sheet sandwiched between the first roller 13a and the second roller 13b is sent in the sheet conveying direction D by the rotation of the first roller 13a and the second roller 13b. The side where the first roller 13a is provided is the front side of the sheet conveying device 200, and the side where the second roller 13b is provided is the back side of the sheet conveying device 200.

[0033] The first roller 13a includes a rotary shaft 13a1 rotatably mounted in a rotation direction R (first rotation direction) and a plurality of sheet conveying portions 13a2 mounted on the circumferential surface of the rotary shaft 13a1 and in contact with the sheet 30. The sheet conveying portions 13a2 are cylindrical members each having an insertion hole at the center through which the rotary shaft 13a1 passes, and are fixed to the rotary shaft 13a1. The rotary shaft 13a1 may be made of a metal such as iron. The sheet conveying portions 13a2 may be made of an elastic material such as rubber.

[0034] Although not shown in FIG. 2, the second roller 13b also has a rotation shaft and a sheet conveying section similar to the first roller 13a, and is arranged so that the rotation shaft is parallel to the rotation shaft 13a1 of the first roller 13a.

[0035] The operating unit 20 is provided at one end (one end) of the rotating shaft 13a1 of the first roller 13a, and is configured so that when clearing a jam, the user can press the gripping portion 22a of the lever 22 downward to rotate the first roller 13a in the rotation direction R and send the sheet 30 in the sheet conveying direction D.

[0036] More specifically, as shown in Figures 3 and 4, the operating unit 20 includes a ratchet unit 21, a lever 22, a return spring 23 (second biasing unit), a slider 24, a torque spring 25 (first biasing unit), a friction washer 26 (disc), a first E-ring 27, a second E-ring 28, and a third E-ring 29.

[0037] As shown in Figure 5 described later, the ratchet portion 21 is a circular member having a hole portion 21a in the center through which the rotating shaft 13a1 is inserted, and a plurality of ratchet teeth 21d (first protrusions), and is configured to rotate together with the rotating shaft 13a1.

[0038] 3 and 4, ratchet portion 21 is provided between one end of rotary shaft 13a1 and sheet conveying portion 13a2, and has ratchet teeth 21d protruding toward one end of rotary shaft 13a1. Ratchet portion 21 is sandwiched between second E-ring 28 and third E-ring 29 provided on rotary shaft 13a1 so as to prevent axial movement on rotary shaft 13a1. The detailed configuration of ratchet portion 21 will be described later.

[0039] Lever 22 includes an annular lever body 22b having an insertion hole 22b1 through which rotation shaft 13a1 is inserted, and a grip 22a that extends from lever body 22b perpendicular to rotation shaft 13a1 and is held by a user. Lever body 22b is located closer to one end of rotation shaft 13a1 than ratchet portion 21 and has lever teeth 22d that protrude toward ratchet portion 21. Lever 22 is provided so as to be movable in the axial and circumferential directions of rotation shaft 13a1. The detailed configuration of lever 22 will be described later.

[0040] The return spring 23 applies a biasing force (second biasing force) to rotate the lever 22 in a rotational direction (second rotational direction) opposite to the rotational direction R. The return spring 23 can be realized by, for example, a kick spring. One end of the return spring 23 is inserted and fixed in a locking hole 43 (see FIG. 9 described later) provided in the roller holder 14, and the other end is inserted and fixed in a hole 22a1 provided in the grip portion 22a of the lever 22.

[0041] The slider 24 is a sliding member provided between the circumferential surface of the insertion hole 22b1 of the lever main body 22b and the rotary shaft 13a1 so that the lever 22 can rotate freely around the rotary shaft 13a1.

[0042] Torque spring 25 applies a biasing force (first biasing force) to lever 22 that acts from one end of rotary shaft 13a1 toward ratchet portion 21 along the axial direction of rotary shaft 13a1. Torque spring 25 can be realized, for example, by a compression coil spring. More specifically, as shown in FIG. 4 , torque spring 25 is provided in a compressed state between an annular friction washer 26, through which rotary shaft 13a1 is inserted, and slider 24, and can apply a biasing force to lever 22 via slider 24. Note that a surface of friction washer 26 on the side of one end of rotary shaft 13a1 is locked by a first E-ring 27 to prevent friction washer 26 from protruding outward from one end of rotary shaft 13a1.

[0043] As described above, the lever 22 is biased by the return spring 23 so as to rotate in a rotational direction opposite to the rotational direction R, and the torque spring 25 is biased in a direction from one end of the rotating shaft 13a1 toward the ratchet portion 21.

[0044] (Ratchet part) The configuration of the ratchet portion 21 will be described in more detail with reference to Figures 5 and 6. Figure 5 is a perspective view showing an example of the configuration of the ratchet portion 21 according to an embodiment of the present disclosure. Figure 6 is a side view of the ratchet portion 21 shown in Figure 5.

[0045] 5 and 6, ratchet portion 21 is a substantially disk-shaped member having a hole 21a at its center through which rotary shaft 13a1 is inserted. A main surface 21b of ratchet portion 21 is provided with a plurality of outer edge portions 21c that extend from hole 21a outward in the radial direction of rotary shaft 13a1, bend along the outer periphery of ratchet portion 21, and protrude toward one end of rotary shaft 13a1 in side view. A plurality of ratchet teeth 21d (first protrusions) are formed by the plurality of outer edge portions 21c.

[0046] 5 and 6, ratchet tooth portion 21d includes first engagement portion 21d2 having an inclined surface that engages with lever tooth portion 22d (described later), and first inclined portion 21d1 having a more gentle inclined surface than first engagement portion 21d2. That is, when ratchet portion 21 is viewed from the side, first inclined portion 21d1 is inclined to form angle α (first angle) with respect to main surface 21b. Meanwhile, first engagement portion 21d2 is inclined to form angle β (second angle) with respect to main surface 21b that is greater than angle α.

[0047] In the ratchet portion 21, the first inclined portion 21d1 is provided on the side of the ratchet teeth portion 21d facing the rotation direction R of the rotary shaft 13a1, and the first engaging portion 21d2 is provided on the opposite side of the rotation direction R of the ratchet teeth portion 21d.

[0048] (lever) Next, the configuration of the lever 22 will be described with reference to Figures 7 and 8. Figure 7 is a plan view showing an example of the lever 22 according to an embodiment of the present disclosure. Figure 8 is a side view of the lever 22 shown in Figure 7.

[0049] 7, lever 22 has grip portion 22a and lever body portion 22b. Grip portion 22a is a plate-like member extending from lever body portion 22b so as to be perpendicular to rotation axis 13a1, and hole 22a1 is provided near lever body portion 22b.

[0050] On the other hand, lever main body 22b is an annular member having insertion hole 22b1 through which rotation shaft 13a1 is inserted, and a main surface 22b2 of lever main body 22b is provided with a plurality of lever teeth 22d (second protrusions) extending in the circumferential direction of rotation shaft 13a1 and provided on the outer periphery of insertion hole 22b1. Each of the plurality of lever teeth 22d protrudes toward the side where ratchet portion 21 is provided in a side view. In addition, guide protrusions 22c protruding perpendicular to rotation shaft 13a1 are provided on the outer circumferential surface of lever main body 22b.

[0051] 7 and 8, lever tooth portion 22d includes second engagement portion 22d2 having an inclined surface that engages with ratchet tooth portion 21d, and second inclined portion 22d1 having a more gentle inclined surface than second engagement portion 22d2. That is, when lever 22 is viewed from the side, second inclined portion 22d1 is inclined to form angle α (first angle) with respect to main surface 22b2. Meanwhile, second engagement portion 22d2 is inclined to form angle β (second angle) with respect to main surface 22b2 that is greater than angle α.

[0052] In the lever 22, the second inclined portion 22d1 is provided on the opposite side of the lever tooth portion 22d in the rotation direction R of the rotation shaft 13a1, and the first engaging portion 21d2 is provided on the rotation direction R side of the lever tooth portion 22d.

[0053] The guide protrusion 22c engages with a guide groove 42 provided in the roller holder 14, which will be described later, and restricts the range of movement in the axial and circumferential directions of the rotation shaft 13a1 of the lever 22. The guide groove 42 will be described in detail later.

[0054] (roller holder) The configuration of the roller holder 14 will be described with reference to Figures 9 and 10. Figure 9 is a perspective view showing an example of the roller holder 14 according to an embodiment of the present disclosure. For ease of explanation, Figure 9 illustrates the end of the roller holder 14 on which the lever 22 is provided. Figure 10 is an enlarged view of part B of the roller holder 14 shown in Figure 9.

[0055] 9, the roller holder 14 includes a roller holder main body 40 and an end cover 41 that protrudes outward from the end of the roller holder main body 40 along the axial direction of the rotation shaft 13a1. The roller holder 14 supports the first roller 13a and the second roller 13b. Here, the configuration for supporting the first roller 13a of the roller holder 14 will be described.

[0056] The roller holder main body 40 extends along the axial direction of the rotation shaft 13a1, and a partition wall 40a that separates the first roller 13a and the second roller 13b (not shown) is erected along the sheet conveying direction D. When the surface of the partition wall 40a on which the first roller 13a is provided is defined as the front surface and the opposite surface is defined as the back surface, the second roller 13b is provided on the back surface side of the partition wall 40a.

[0057] The partition wall 40a has a plurality of communication holes 40b provided so that the first roller 13a and the second roller 13b communicate with each other. Each of the plurality of sheet conveying portions 13a2 provided on the first roller 13a comes into contact with a sheet conveying portion (not shown) of the second roller 13b provided on the back side of the partition wall 40a through each of the plurality of communication holes 40b.

[0058] A roller support portion 40c that rotatably supports the first roller 13a and locks the first roller 13a so that it does not move in the axial direction of the rotation shaft 13a1 is provided at an end of the roller holder main body 40. The roller support portion 40c is a flat plate member that protrudes from the partition wall 40a toward the front side in a direction perpendicular to the axial direction of the rotation shaft 13a1, and is provided with a hole through which the rotation shaft 13a1 is inserted.

[0059] Further, an end cover portion 41 is provided so as to protrude outward from the roller support portion 40c along the axial direction of the rotary shaft 13a1.

[0060] The roller support portion that supports the rotation shaft of second roller 13b also has an end cover portion that protrudes outward along the axial direction of the rotation shaft of second roller 13b. However, end cover portion 41 provided for first roller 13a differs from the end cover portion provided for second roller 13b in that it further includes a guide groove 42 and a return spring locking hole 43.

[0061] The return spring locking hole 43 is a hole through which the other end of the return spring 23 is inserted and fixed.

[0062] The guide groove 42 is a groove that engages with the guide protrusion 22c of the lever 22 and restricts the movement of the guide protrusion 22c, thereby regulating the movement range of the lever 22. The groove shape of the guide groove 42 is a substantially rectangular parallelepiped with the vertical direction as its longitudinal axis. As shown in FIG. 10 , the guide groove 42 includes a pair of side walls extending in the vertical direction, a first side portion 42a located on one end side of the rotation shaft 13a1, a second side portion 42b located on the opposite side, an upper end portion 42c connecting the upper ends of the first side portion 42a and the second side portion 42b, a first curved portion 42d that curves from the lower end of the first side portion 42a toward one end side of the rotation shaft 13a1, and a second curved portion 42e that curves from the lower end of the second side portion 42b toward one end side of the rotation shaft 13a1 and connects to the first curved portion 42d.

[0063] The area surrounded by the first curved portion 42d and the second curved portion 42e and tapering toward one end of the rotating shaft 13a1 is a retreat portion, and a guide portion is formed in the area extending upward from this retreat portion and surrounded by the retreat portion, the first side portion 42a, and the second side portion 42b.

[0064] The guide groove 42 has a groove width that allows the guide protrusion 22c to move in the axial direction of the rotation shaft 13a1 in the guide portion. In other words, the distance between the first side portion 42a and the second side portion 42b is sized to allow the guide protrusion 22c to move from a separation position where the lever tooth portion 22d is separated from the ratchet tooth portion 21d to an engagement position where the lever tooth portion 22d is engaged with the ratchet tooth portion 21d.

[0065] Here, the relationship between the position of the guide protrusion 22c in the guide groove 42 and the positions of the ratchet teeth 21d and the lever teeth 22d will be described with reference to Fig. 11. Fig. 11 is a cross-sectional view taken along line XI-XI of the sheet conveying device 200 shown in Fig. 2. Fig. 11 shows the positional relationship of the guide protrusion 22c in the guide groove 42.

[0066] That is, when guide protrusion 22c is at position P1 in FIG. 11 (a state in which guide protrusion 22c is in the retracted portion), lever teeth 22d and ratchet teeth 21d are in a separated position. When guide protrusion 22c is at position P2, lever teeth 22d and ratchet teeth 21d are engaged. Position P3 of guide protrusion 22c is the end of the range of movement of lever 22 when lever teeth 22d and ratchet teeth 21d are engaged. The angle of the movable range of guide protrusion 22c, i.e., the angle between P2 and P3, can be approximately 60 degrees. This movable range can be adjusted by the number of teeth provided on ratchet teeth 21d and lever teeth 22d, respectively.

[0067] More specifically, when the guide protrusion 22c is at position P1, the guide protrusion 22c is located in the retracted portion of the guide groove 42, as shown in FIG. 12. When the guide protrusion 22c is located in the retracted portion, the lever tooth portion 22d and the ratchet tooth portion 21d are spaced apart, as shown in FIG. 13. That is, FIG. 12 is a rear view of the operating unit 20 when the lever tooth portion 22d and the ratchet tooth portion 21d are in the spaced apart position. Note that, for ease of explanation, the roller holder main body 40 is not shown in FIG. 12. FIG. 13 is a cross-sectional view showing an example of the cross-sectional structure of the operating unit 20 shown in FIG. 12. FIG. 13 shows the cross-sectional structure of the operating unit 20 shown in FIG. 11 when viewed from the front.

[0068] 13, when lever tooth portion 22d and ratchet tooth portion 21d are in the separated position, guide protrusion portion 22c is pressed against the side of the retracted portion of guide groove 42 by the biasing force of return spring 23 acting on lever 22 as shown in Fig. 12. In this way, during printing in image forming apparatus 100, lever tooth portion 22d and ratchet tooth portion 21d are in the separated position, and guide protrusion portion 22c is maintained so as not to move in the axial direction of rotation shaft 13a1 in the retracted portion.

[0069] When sheet 30 becomes jammed at registration roller 13, the user pushes down gripping portion 22a of lever 22 against the biasing force of return spring 23 so that the tip of gripping portion 22a faces downward. When gripping portion 22a is pushed down in this manner, lever tooth portion 22d moves toward ratchet tooth portion 21d due to the biasing force of torque spring 25. At this time, guide protrusion 22c moves from the retracted portion toward ratchet portion 21 along second curved portion 42e to position P2 shown in FIG. 14, and lever tooth portion 22d engages with ratchet tooth portion 21d as shown in FIG. 15.

[0070] Fig. 14 is a rear view of the operating unit 20 when the lever tooth portion 22d and the ratchet tooth portion 21d are in the engagement position. For ease of explanation, the roller holder main body 40 is not shown in Fig. 14. Fig. 15 is a cross-sectional view showing an example of the cross-sectional structure of the operating unit 20 shown in Fig. 14. Fig. 15 shows the cross-sectional structure of the operating unit 20 shown in Fig. 14 when viewed from the front.

[0071] When lever tooth portion 22d and ratchet tooth portion 21d are in the engaged position, if the user grips grip portion 22a of lever 22 and pushes the tip of grip portion 22a further downward, ratchet tooth portion 21d, which is engaged with lever tooth portion 22d, rotates in response to the rotation of lever tooth portion 22d. Along with this rotation of ratchet tooth portion 21d, rotation shaft 13a1 also rotates. As a result, sheet 30 jammed in registration roller 13 moves in sheet conveyance direction D.

[0072] With the lever tooth portion 22d and the ratchet tooth portion 21d engaged as shown in FIG. 17, the guide protrusion portion 22c moves to the position P3 as shown in FIGS. 11 and 16. FIG. 16 is a rear view of the operating unit 20 when the lever tooth portion 22d and the ratchet tooth portion 21d are in the engaged position and the guide protrusion portion 22c has moved to its end. For ease of explanation, the roller holder main body 40 is not shown in FIG. 16. FIG. 17 is a cross-sectional view showing an example of the cross-sectional structure of the operating unit 20 shown in FIG. 16. FIG. 17 shows the cross-sectional structure of the operating unit 20 shown in FIG. 16 when viewed from the front.

[0073] When the user presses down on grip portion 22a and guide protrusion 22c moves to position P3, and then the user releases grip portion 22a, grip portion 22a pressed down by the user moves upward as shown in Fig. 18 due to the biasing force of return spring 23, and guide protrusion 22c moves from P3 to P4. Fig. 18 is a cross-sectional view of sheet conveying device 200 shown in Fig. 2 taken along line XI-XI. Fig. 18 shows a transition state from the position of lever 22 when guide protrusion 22c is at P3 to the position of lever 22 when guide protrusion 22c is at P4.

[0074] That is, the biasing force of return spring 23 is greater than the biasing force of torque spring 25. Therefore, the force acting in the rotational direction (second rotational direction) opposite to rotational direction R of return spring 23 causes second inclined portion 22d1 of lever tooth portion 22d to climb over first inclined portion 21d1 of ratchet tooth portion 21d, and guide protrusion 22c moves from P3 to P4. Finally, the biasing force of return spring 23 returns lever 22 to position P1.

[0075] Here, first inclined portion 21d1 and second inclined portion 22d1 are gently inclined, and guide groove 42 has a groove width that allows guide protrusion 22c to move in the axial direction of rotation shaft 13a1. Therefore, lever tooth 22d can easily climb over ratchet tooth 21d. Once lever tooth 22d climbs over ratchet tooth 21d, lever tooth 22d is pushed toward the base end of ratchet tooth 21d by the biasing force of torque spring 25, and lever tooth 22d and ratchet tooth 21d engage with each other, as shown in FIG. 19 . Then, the user again pushes down grip portion 22a of lever 22 against the biasing force of return spring 23 so that the tip of grip portion 22a faces downward, thereby rotating ratchet portion 21 and thus rotating rotation shaft 13a1.

[0076] By repeating this process, the sheet 30 jammed in the registration rollers 13 is sent out from the registration rollers 13 and can be removed by the user.

[0077] 19 is a cross-sectional view showing an example of the cross-sectional structure of the operation unit 20. Fig. 19 shows the cross-sectional structure of the operation unit 20 when viewed from the front side when the guide protrusion 22c is positioned at P4.

[0078] As described above, the sheet conveying device 200 according to the present embodiment can easily remove the sheet 30 jammed in the registration rollers 13 without using a one-way clutch. Therefore, the sheet conveying device 200 can perform jam clearance with a simple configuration.

[0079] Furthermore, one-way clutches have a complex internal structure and are expensive. Furthermore, the sliding surface between the inner ring of the one-way clutch and the rotating shaft is subject to friction and wear, so the rotating shaft must be made of stainless steel, which is strong but expensive. In contrast, the sheet conveying device 200 according to this embodiment has a simple configuration and does not require the rotating shaft to be made of stainless steel, which reduces manufacturing costs compared to sheet conveying devices that use one-way clutches. [Explanation of symbols]

[0080] 9 Sheet transport path 13 Registration roller 13a First Roller 13a1 Rotation axis 13a2 Sheet transport section 13b Second Roller 14 Roller holder 20 Control section 21 Ratchet section 21a Hole 21b Main surface 21c outer edge 21d Ratchet teeth 21d1 1st slope part 21d2 First engaging part 22 Lever 22a Gripping part 22a1 Hole 22b Lever body 22b1 Insertion hole 22b2 Main surface 22c Guide protrusion 22d Lever teeth 22d1 2nd slope part 22d2 Second engaging part 24 Slider 26 Friction washer 30 sheets 40 Roller holder main body 40c Roller support 41 End cover part 42 Guide groove 42a First side 42b Second side 42c Upper end 42d First curved section 42e Second curved section 43 Locking hole 100 Image forming device

Claims

1. a conveying roller having a rotating shaft and a sheet conveying portion that is provided on the other end side of the rotating shaft from one end thereof and that contacts the sheet, and that rotates in a first rotation direction when conveying the sheet; a ratchet portion provided between one end of the rotary shaft and the sheet conveying portion so as to rotate together with the rotary shaft, the ratchet portion having a first protrusion protruding toward the one end of the rotary shaft; a lever having a main body portion provided with an insertion hole through which the rotary shaft is inserted, a grip portion extending from the main body portion perpendicular to the rotary shaft, and a second protrusion portion protruding from the main body portion toward the ratchet portion, the lever being provided on one end side of the rotary shaft closer to the ratchet portion so as to be movable in the axial direction and the circumferential direction of the rotary shaft; a first biasing portion that applies a first biasing force to the lever, the first biasing force acting from one end of the rotation shaft toward the ratchet portion along the axial direction; a second biasing portion that applies a second biasing force to the lever to rotate the lever in a second rotation direction that is opposite to the first rotation direction, the lever is at a spaced position where the second protrusion is spaced from the first protrusion by the second biasing force, When the lever is rotated in the first rotation direction against the second biasing force, the first biasing force moves the second protrusion from the separated position to an engaged position where the second protrusion engages with the first protrusion, When the lever is further rotated in the first rotation direction at the engagement position, the conveying roller rotates in the first rotation direction via the ratchet portion.

2. a roller holder that supports the conveying roller; 2. The sheet conveying device according to claim 1, wherein one end of the second biasing portion is engaged with the roller holder and the other end is engaged with the lever.

3. The rotary shaft further includes a circular plate engaged with the rotary shaft at a position closer to one end of the rotary shaft than the first biasing portion, The sheet transport device according to claim 2 , wherein the first biasing portion is provided in a compressed state between the disk and the lever.

4. The main body has a guide protrusion that protrudes perpendicular to the rotation axis, 3. The sheet conveying device according to claim 2, wherein the roller holder includes a guide groove for guiding the guide protrusion so that the lever moves from the separated position to the engaged position as the lever rotates.

5. 5. The sheet conveying device according to claim 4, wherein the guide groove has a retraction portion that engages the guide protrusion so that the lever maintains the separated position, and a guide portion that guides the guide protrusion so that the first biasing force moves the lever from the separated position to the engaged position.

6. The sheet conveying device according to claim 5 , wherein the guide portion has a groove width that allows the guide protrusion portion to move along the axial direction.

7. the ratchet portion has an outer edge portion on a main surface on one end side of the rotary shaft, the outer edge portion extending radially outward from the rotary shaft, and the first protrusion portion is constituted by the outer edge portion; The first protrusion is a first inclined portion having an inclined surface that is inclined at a first angle with respect to a main surface of the ratchet portion in a side view; a first engagement portion having an inclined surface inclined at a second angle greater than the first angle with respect to the main surface of the ratchet portion, In the lever, the second protrusion is provided on a main surface of the main body on the ratchet portion side along a circumferential direction of the rotation shaft, The second protrusion is a second inclined portion having an inclined surface inclined at the first angle with respect to the main surface of the main body portion in a side view; and a second engaging portion having an inclined surface inclined at the second angle with respect to the main surface of the main body portion and engaging with the first engaging portion, the first inclined portion is provided on a side of the first protrusion in the first rotation direction, the first engagement portion is provided on a side of the first protrusion in the second rotation direction, the second inclined portion is provided on the second protrusion portion on a side of the second rotation direction, The sheet conveying device according to claim 1 , wherein the second engagement portion is provided on a side of the second protrusion in the first rotation direction.

8. An image forming apparatus comprising the sheet conveying device according to claim 1 .

Images