Medium feeding device and image reading device

Abstract

To suppress occurrence of skewing by suppressing a direction of a feeding force of a feeding roller 8 from being tilted.SOLUTION: A medium feeding device 23 comprises a separation part 15 disposed to face a feeding roller 8 for separating a medium, a guide part 24 for guiding the medium toward the feeding roller, and a support part 25 for supporting the guide part. The guide part includes a shaft body part 26 extending in a direction crossing a feeding direction of the medium, a guide rib 29 which extends from the shaft body part in the feeding direction for guiding the medium toward the feeding roller and has a contact part 28 being brought into contact with an outer peripheral surface 27 of the feeding roller, and an elastic force generation part 30 for generating an elastic force for pressing the contact part in a direction contacting to the outer peripheral surface. The guide part is supported by the support part so as to displace an attitude by following an attitude of the outer peripheral surface in a state where the contact part is brought into contact with the outer peripheral surface.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a medium feeding device and an image reading device.

Background Art

[0002] As an example of this type of device, there is a medium feeding device described in Patent Document 1. In Patent Document 1, the hopper is formed in a flat plate shape on which paper can be placed, and is disposed inside the first support between the right side wall and the left side wall of the frame. The lower end is located near the paper feed roller, and the upper end is disposed so as to be close to the top of the rear wall of the frame. The hopper has the other end of a compression spring (not shown) whose one end is attached to the rear wall of the frame attached to the back surface on the lower end side. By the expansion and contraction of this compression spring, the lower end side pivots about the upper end side, and the lower end of the stored paper is pressed against and separated from the paper feed roller 32.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the medium feeding device described in Patent Document 1, with the hopper pivoted to press the paper against the paper feed roller, the paper feed roller rotates to apply a paper feed force to the paper and send the paper in the paper feed direction. If there is a left-right difference in the movement of the hopper, the direction of the paper feed force received by the paper from the paper feed roller tends to tilt, so the paper is sent while tilted, that is, skew is likely to occur. Also, the posture of the outer peripheral surface of the roller in contact with the paper may vary due to variations in the assembled state of the paper feed roller. In this case as well, the direction of the paper feed force tends to tilt, so skew is likely to occur. Patent Document 1 does not have any description regarding suppressing the occurrence of skew based on these points.

Means for Solving the Problems

[0005] To solve the above problems, a medium feeding device according to the present invention includes a feeding roller that feeds a medium placed on a placement portion in a feeding direction, a separating portion that is disposed opposite to the feeding roller and separates the medium by nipping with the feeding roller, a guide portion that guides the medium toward the feeding roller, and a support portion that supports the guide portion. The guide portion includes a shaft body portion that extends in a direction intersecting the feeding direction of the medium, a guide rib that extends from the shaft body portion in the feeding direction to guide the medium toward the feeding roller and contacts the outer peripheral surface of the feeding roller, and an elastic force generating portion that generates an elastic force for pressing the contact portion in a direction of contacting the outer peripheral surface. The guide portion is supported by the support portion so as to be posture-displaceable following the posture of the outer peripheral surface in a state where the contact portion contacts the outer peripheral surface.

[0006] An image reading apparatus according to the present invention includes a medium conveyance device according to any one of the first aspect to the seventh aspect described later, and a reading portion that reads an image of the medium.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0008] First, the present invention will be briefly described below. A first aspect of the medium feeding device according to the present invention includes a feeding roller that feeds a medium placed on a placement portion in a feeding direction, a separating portion that is disposed opposite to the feeding roller and separates the medium by nipping with the feeding roller, a guide portion (having a guiding surface) that guides the medium toward the feeding roller, and a supporting portion that supports the guide portion. The guide portion includes a shaft body portion that extends in a direction intersecting the feeding direction of the medium, a guide rib that extends from the shaft body portion in the feeding direction to guide the medium toward the feeding roller and contacts an outer peripheral surface of the feeding roller, and an elastic force generating portion that generates an elastic force for pressing the contact portion in a direction of contacting the outer peripheral surface. The guide portion is supported by the supporting portion such that the guide portion can be displaced in posture following the posture of the outer peripheral surface in a state where the contact portion is in contact with the outer peripheral surface.

[0009] Here, "the guide portion can be displaced in posture following the posture of the outer peripheral surface" in "the guide portion is supported by the supporting portion such that the guide portion can be displaced in posture following the posture of the outer peripheral surface in a state where the contact portion is in contact with the outer peripheral surface" means that the position of the guide portion is not fixed, and even if the posture of the outer peripheral surface varies due to variations in the assembled state of the feeding roller, the guide portion is supported by the supporting portion such that the guide portion can change its posture following the posture of the outer peripheral surface in a state where the contact portion is in contact with the outer peripheral surface.

[0010] According to this aspect, the guide portion includes a shaft body portion that extends in a direction intersecting the feeding direction, a guide rib that extends from the shaft body portion in the feeding direction and contacts the outer peripheral surface of the feeding roller, and an elastic force generating portion that generates an elastic force for pressing the contact portion in a direction of contacting the outer peripheral surface. And the guide portion is supported by the supporting portion such that the guide portion can be displaced in posture following the posture of the outer peripheral surface in a state where the contact portion is in contact with the outer peripheral surface. As a result, even if there is variation in the attitude of the outer peripheral surface of the feed roller in contact with the medium due to variation in the assembled state of the feed roller, the guide portion is supported by the support portion so as to be capable of attitude displacement following the attitude of the outer peripheral surface. Therefore, it is possible to suppress the inclination of the feeding force direction of the feed roller due to the attitude displacement following, and thus suppress the occurrence of skew.

[0011] A second aspect of the medium feeding device according to the present invention is an aspect subordinate to the first aspect, wherein the support portion includes a fulcrum that swingably supports the shaft body portion, and a bearing portion having shaft holes that pivotally support both end portions of the shaft body portion, and the shaft holes are elongated holes that are long in a direction that enables displacement of the attitude of the guide portion.

[0012] According to this aspect, the support portion includes a fulcrum that swingably supports the shaft body portion and a bearing portion having shaft holes that pivotally support both end portions of the shaft body portion. And the shaft holes are elongated holes that are long in a direction that enables displacement of the attitude of the guide portion. As a result, a structure in which the guide portion can be displaced in attitude following the attitude of the outer peripheral surface can be easily realized. Further, since both end portions of the shaft body portion are pivotally supported in a state of being inserted into the shaft holes of the bearing portion, even if the device receives an impact due to dropping or the like, the possibility of the guide portion falling off can be reduced.

[0013] A third aspect of the medium feeding device according to the present invention is an aspect subordinate to the second aspect, wherein the fulcrum is located at the center in the extending direction of the shaft body portion.

[0014] According to this aspect, since the fulcrum is located at the center in the extending direction of the shaft body portion, it is easy to achieve a structural balance of the guide portion in the extending direction of the shaft body portion.

[0015] A fourth aspect of the medium feeding device according to the present invention is an aspect dependent on the first aspect, characterized in that a contact position of the contact portion with the outer peripheral surface is upstream of a nip position between the feeding roller and the separating portion in the feeding direction. Note that this aspect can also be made dependent on the second aspect or the third aspect.

[0016] According to this aspect, the contact position of the contact portion with the outer peripheral surface is upstream of the nip position between the feeding roller and the separating portion in the feeding direction. That is, the medium is nipped by the feeding roller and the separating portion in a state where skew of the medium is suppressed by the guide portion. Thereby, it is possible to suppress the occurrence of skew in the medium separated by the separating portion.

[0017] A fifth aspect of the medium feeding device according to the present invention is an aspect dependent on the first aspect, characterized in that the guide rib includes a first guide rib and a second guide rib positioned apart from the first guide rib in a direction intersecting the feeding direction. Note that this aspect can also be made dependent on any one of the second aspect to the fourth aspect.

[0018] According to this aspect, the first guide rib and the second guide rib forming the guide rib are in contact with the outer peripheral surface of the feeding roller at positions separated from each other. Thereby, it is easy to equalize the contact pressure of the first guide rib and the contact pressure of the second guide rib on the outer peripheral surface. Also, the contact posture of the guide rib with respect to the outer peripheral surface is stabilized.

[0019] A sixth aspect of the medium feeding device according to the present invention is an aspect dependent on the fifth aspect, characterized in that the first guide rib and the second guide rib are arranged symmetrically with respect to a center in a direction intersecting the feeding direction of the feeding roller.

[0020] According to this aspect, the first guide rib and the second guide rib are arranged symmetrically with respect to the center in the direction intersecting the feeding direction. Due to this symmetrical arrangement, the balance of the contact positions between the outer peripheral surface of the feeding roller and the first guide rib and the second guide rib is improved, and it is possible to effectively suppress the inclination of the direction of the feeding force of the feeding roller.

[0021] A seventh aspect of the medium feeding device according to the present invention is an aspect dependent on the sixth aspect, characterized in that the first guide rib and the second guide rib contact the outer peripheral surface at positions at both ends in the direction intersecting the feeding direction of the feeding roller.

[0022] According to this aspect, the first guide rib and the second guide rib contact the outer peripheral surface at the positions at both ends of the feeding roller. Thereby, the occurrence of skew can be effectively suppressed.

[0023] An eighth aspect of the image reading device according to the present invention is characterized by including a medium feeding device according to any one of the first to seventh aspects and a reading unit that reads an image of the medium.

[0024] According to this aspect, in the image reading device, an effect similar to the effect according to any one of the first to seventh aspects can be obtained.

[0025] [Embodiment] Hereinafter, embodiments of the medium feeding device and the image reading device according to the present invention will be specifically described with reference to FIGS. 1 to 7. In the following description, as shown in each figure, the three axes orthogonal to each other are defined as the X-axis, Y-axis, and Z-axis, respectively. The directions indicated by the arrows of the three axes (X, Y, Z) are the + directions of each direction, and the opposite directions are the - directions. The Z-axis direction corresponds to the vertical direction, that is, the direction in which gravity acts. The +Z direction indicates vertically upward, and the -Z direction indicates vertically downward. The X-axis direction and the Y-axis direction correspond to the horizontal direction. The +Y direction indicates the front direction of the image reading device, and the -Y direction indicates the rear direction of the device. The +X direction indicates the right direction of the device, and the -X direction indicates the left direction of the device.

[0026] <Overall Configuration of Image Reading Device> The image reading device 1 of the present embodiment is a document scanner capable of reading an image of a medium 2. Here, the image means what is visually recorded on the medium 2, and is, for example, characters, figures, tables, pictures, photographs, etc. The medium is not limited to a sheet, and includes cards, brochures, etc. As shown in FIG. 1, the image reading device 1 includes reading units 31 and 32 that read an image of the medium 2, a first conveyance roller 5 provided upstream of the reading units 31 and 32 in the conveyance direction F for conveying the medium 2 along the conveyance path 4 in the conveyance direction F, and a second conveyance roller 6 provided downstream of the reading units 31 and 32. Upstream of the first conveyance roller 5 in the conveyance direction F, a feed roller 8 is arranged to send out the medium 2 set on the placement unit 7 on which the medium 2 is placed toward the first conveyance roller 5 in the conveyance direction F.

[0027] In the present embodiment, both the first conveyance roller 5 and the second conveyance roller 6 are nip rollers that nip and convey the medium 2. Specifically, the first conveyance roller 5 is composed of a pair of an upper first conveyance roller 51 and a lower first conveyance roller 52 that sandwiches and conveys the medium 2 with the upper first conveyance roller 51 at the first nip position 9. The second conveyance roller 6 is composed of a pair of an upper second conveyance roller 61 and a lower second conveyance roller 62 that sandwiches and conveys the medium 2 with the upper second conveyance roller 61 at the second nip position 10.

[0028] Further, the upper first conveying roller 51, the lower first conveying roller 52, the upper second conveying roller 61, and the lower second conveying roller 62 are each composed of two rollers that are spaced apart from each other in the axial direction and are located at two positions on the respective rotation shafts 11, 12, 13, 14. Each of the rotation shafts 11, 12, 13, 14 is rotatably supported by a bearing (not shown). The feeding roller 8 forms a nip roller in pair with the separating roller 15 which is an example of a separating unit. In FIG. 1, reference numeral 22 indicates the nip position. The feeding roller 8 is a driving roller that feeds the medium 2 placed on the placing portion 7 in the feeding direction F by the rotation of the rotation shaft 16. Here, since the feeding direction F is the same as the conveying direction F, the same reference numeral F is used. The separating roller 15 is a roller for separating one medium 2 from the bundle of media and sending it in the feeding direction F. The separating roller 15 is provided with a torque limiter (not shown) on the rotation shaft 17. When only one medium 2 is being fed, a torque exceeding the set value is applied to the torque limiter, and it rotates in the feeding direction F together with the feeding roller 8. The separating roller 15 only needs to be able to perform the function of separating the medium 2 and may be a roller to which no driving force is transmitted. Also, the separating roller 15 may be a driving roller that rotates in the direction opposite to the feeding direction F.

[0029] As shown in FIG. 1, in this embodiment, a curved reversing path 19 which forms a part of the conveying path 18 is provided downstream of the second conveying roller 6 in the conveying direction F. An intermediate roller pair 20 is arranged at the downstream end portion of the curved reversing path 19, and further downstream of that, a discharging roller pair 21 is arranged. The medium 2 discharged after passing through the discharging roller pair 21 is supported and held on the receiving surface of a discharging receiving portion (not shown).

[0030] The operations of the feeding roller 8, the first conveying roller 5, the second conveying roller 6, the intermediate roller pair 20, the discharging roller pair 21, and the reading units 31, 32 are executed by a control unit (not shown). The control unit includes a CPU, a flash ROM, and a RAM. The CPU performs various arithmetic processes according to the programs stored in the flash ROM and controls the operations of the entire image reading apparatus 1. The flash ROM, which is an example of the storage means, is a non-volatile memory that can be read from and written to. Various kinds of information are temporarily stored in the RAM, which is an example of the storage means.

[0031] <Media feeding device> The image reading apparatus 1 includes a media feeding device 23. The media feeding device 23 feeds the media 2 placed on the placement unit 7 in the feeding direction F. The fed media 2 is conveyed through the reading areas of the reading units 31 and 32 by the first conveying roller 5, and the image is read, and then further conveyed downstream by the second conveying roller 6. The media feeding device 23 includes a feeding roller 8 that feeds the media 2 placed on the placement unit 7 in the feeding direction F, and a separating roller 15 that is arranged opposite to the feeding roller 8 and separates the media 2 by nipping with the feeding roller 8 and is a separating unit. Further, it includes a guide unit 24 that guides the media 2 toward the feeding roller 8, and a support unit 25 (FIG. 2) that supports the guide unit 24.

[0032] As shown in FIGS. 2 and 3, the guide unit 24 includes a shaft body portion 26 that extends in a direction (X-axis direction) intersecting the feeding direction F of the media 2, and a guide rib 29 that extends from the shaft body portion 26 in the feeding direction F and guides the media 2 toward the feeding roller 8. The guide rib 29 has a contact portion 28 that contacts the outer peripheral surface 27 of the feeding roller 8. The guide unit 24 further includes an elastic force generating portion 30 that generates an elastic force for pressing the contact portion 28 in the direction of contacting the outer peripheral surface 27. Then, the guide unit 24 is supported by the support unit 25 so that it can be displaced in posture following the posture of the outer peripheral surface 27 in a state where the contact portion 28 contacts the outer peripheral surface 27. Here, "capable of posture displacement following the posture of the outer peripheral surface 27" means that the guide portion 24 is not fixed in position, and even if there is variation in the posture of the outer peripheral surface 27 due to variation in the assembled state of the feed roller 8, the contact portion 28 is supported by the support portion 25 in such a structure that it can change its posture following the posture of the outer peripheral surface 27 while being in contact with the outer peripheral surface 27. In the present embodiment, the shaft body portion 26 has a substantially rectangular parallelepiped-shaped base portion 261 and cylindrical shaft portions 262 and 263 located at both ends in the longitudinal direction (X-axis direction) of the base portion 261. Further, a guide rib 29 projects from the side surface on the feed roller 8 side of the base portion 261 in the feed direction F.

[0033] ≪Support portion≫ As shown in FIGS. 2 and 4, in the present embodiment, the support portion 25 includes a fulcrum 33 that swingably supports the shaft body portion 26, bearing portions 351 and 352 having shaft holes 341 and 342 that pivotally support the shaft portions 262 and 263 located at both ends of the shaft body portion 26, and a base plate portion 36. The fulcrum 33 and the bearing portions 351 and 352 are provided on the base plate portion 36. Here, the fulcrum 33, the bearing portions 351 and 352, the base plate portion 36, and the shaft holes 341 and 342 are formed by integral molding of synthetic resin. The support portion 25 is fixed to a frame (not shown) that is a skeletal member of the medium feeding device 23. The shaft holes 341 and 342 are long holes 37 that are long in a direction that allows displacement of the posture of the guide portion 24. The dimension in the longitudinal direction of the long hole 37 is set to a dimension that does not restrict, that is, allows, the displacement of the shaft portions 262 and 263 even when the posture of the guide portion 24 is displaced following the posture of the outer peripheral surface 27 in a state where the guide rib 29 is in contact with the outer peripheral surface 27 of the feed roller 8. The guide portion 24 is supported in a state where a protrusion 50 projecting from the bottom of the base portion 261 of the shaft body portion 26 is in contact with the fulcrum 33.

[0034] As shown in FIG. 4, in the present embodiment, the fulcrum 33 is configured to be located at the center C in the X-axis direction, which is the extending direction of the shaft body portion 26. Correspondingly, the protrusion 50 that contacts the fulcrum 33 is located at the center C in the X-axis direction, which is the extending direction of the shaft body portion 26. In addition, when other structural members are arranged at the center C, the fulcrum 33 and the protrusion 50 may be arranged by shifting them to positions near the center C. Also, as shown in FIG. 3, the contact position 38 where the contact portion 28 of the guide rib 29 contacts the outer peripheral surface 27 of the feed roller 8 is upstream of the nip position 22 between the feed roller 8 and the separation roller 15 in the feed direction F.

[0035] ≪Guide rib≫ As shown in FIGS. 2 to 4, in the present embodiment, the guide rib 29 includes a first guide rib 291 and a second guide rib 292 that is located away from the first guide rib 291 in the X-axis direction, which is a direction intersecting the feed direction F. The first guide rib 291 and the second guide rib 292 are arranged symmetrically with respect to the center C, that is, the center C, in the X-axis direction, which is a direction intersecting the feed direction F of the feed roller 8. Specifically, the positions of the contact portions 28 of the first guide rib 291 and the second guide rib 292 are arranged symmetrically with respect to the line. Furthermore, as shown in FIG. 4, in the present embodiment, the first guide rib 291 and the second guide rib 292 are configured to contact the outer peripheral surface 27 at the positions of both ends P1 and P2 in the X-axis direction, which is a direction intersecting the feed direction F of the feed roller 8.

[0036] ≪Elastic force generating portion≫ In the present embodiment, the elastic force generating portion 30 is composed of a torsion coil spring 40. As shown in FIGS. 2 to 4, the torsion coil spring 40 is provided on each of the shaft portions 262 and 263. The torsion coil spring 40 has an L-shaped locking portion 42 formed at the tip of one elastic piece 41 inserted and locked into the respective holes 45 formed in the bearing portions 351 and 352. Note that the hole 45 of the bearing portion 352 is located at a position not shown in the figure. The other elastic piece 43 of the torsion coil spring 40 is assembled in a state where its tip is pressed against the convex portions 44 provided at both side ends of the base portion 261. That is, the torsion coil spring 40 applies an elastic force that presses each contact portion 28 of the first guide rib 291 and the second guide rib 292 against the outer peripheral surface 27 of the feed roller 8. As a result, the guide portion 24 is supported via the protrusion 50 at the fulcrum 33 of the support portion 25, and each contact portion 28 of the first guide rib 291 and the second guide rib 292 is pressed against the outer peripheral surface 27 of the feed roller 8 by the elastic force of the torsion coil spring 40. This state is the state in which the guide portion 24 is used.

[0037] <Explanation of the attitude displacement of the guide portion following the attitude of the outer peripheral surface of the feed roller> FIGS. 4 and 5 show the case where the feed roller 8 is assembled almost as designed. In this case, each contact portion 28 of the first guide rib 291 and the second guide rib 292 is pressed against the outer peripheral surface 27 of the feed roller 8 by the torsion coil spring 40 and follows the attitude of the outer peripheral surface 27, and the shaft portions 262 and 263 of the guide portion 24 are located substantially at the centers of the shaft holes 341 and 342 of the support portion 25. FIGS. 6 and 7 show the case where the feed roller 8 is assembled with a slight deviation from the design. In this case, each contact portion 28 of the first guide rib 291 and the second guide rib 292 is pressed against the outer peripheral surface 27 of the feed roller 8 by the torsion coil spring 40 and follows the attitude of the outer peripheral surface 27, and the shaft portions 262 and 263 of the guide portion 24 are not located at the centers of the shaft holes 341 and 342 of the support portion 25. Here, one shaft portion 262 is displaced upward in the figure within the long hole 37, and the other shaft portion 263 is displaced downward in the figure within the long hole 37. In any case, the direction of the feeding force of the feeding roller 8 is suppressed from being inclined by the posture displacement following the above, and thus the occurrence of skew can be suppressed.

[0038] <Description of the effects of Embodiment 1> (1) In the present embodiment, the guide portion 24 includes a shaft body portion 26 extending in a direction intersecting the feeding direction F, a guide rib 29 having a contact portion 28 extending from the shaft body portion 26 in the feeding direction F and contacting the outer peripheral surface 27 of the feeding roller 8, and an elastic force generating portion 30 that generates an elastic force for pressing the contact portion 28 in the direction of contacting the outer peripheral surface 27. And the guide portion 24 is supported by the support portion 25 so as to be posture-displaceable following the posture of the outer peripheral surface 27 in a state where the contact portion 28 is in contact with the outer peripheral surface 27. Thereby, even if there are variations in the posture of the outer peripheral surface 27 of the feeding roller 8 in contact with the medium 2 due to variations in the assembled state of the feeding roller 8, the guide portion 24 is supported by the support portion 25 so as to be posture-displaceable following the posture of the outer peripheral surface 27. Therefore, the direction of the feeding force of the feeding roller 8 is suppressed from being inclined by the posture displacement following the above, and thus the occurrence of skew can be suppressed.

[0039] (2) Further, in the present embodiment, the support portion 25 includes a fulcrum 33 that swingably supports the shaft body portion 26, and bearing portions 351, 352 having shaft holes 341, 342 that pivotally support shaft portions 262, 263 at both ends of the shaft body portion 26. And the shaft holes 341, 342 are long holes 37 that are long in a direction that allows displacement of the posture of the guide portion 24. Thereby, a structure in which the guide portion 24 can be posture-displaced following the posture of the outer peripheral surface 27 can be easily realized. Further, since the shaft portions 262, 263 at both ends of the shaft body portion 26 are pivotally supported in a state of being inserted into the shaft holes 341, 342 of the bearing portions 351, 352, even when receiving an impact due to the dropping of the device or the like, the risk of the guide portion 24 falling off can be reduced.

[0040] (3) Further, in the present embodiment, since the fulcrum 33 is located at the center C in the extending direction of the shaft body portion 26, it is easy to achieve a structural balance of the shaft body portion 26 of the guide portion 24 in the extending direction. (4) Further, in the present embodiment, the contact position 38 with the outer peripheral surface 27 of the contact portion 28 is upstream of the nip position 22 of the feed roller 8 and the separation roller 15 in the feed direction F. That is, the medium 2 is nipped by the feed roller 8 and the separation roller 15 in a state where the skew of the medium 2 is suppressed by the guide portion 24. Thereby, it is possible to suppress the occurrence of skew in the medium 2 separated by the separation roller 15.

[0041] (5) Further, in the present embodiment, the first guide rib 291 and the second guide rib 292 forming the guide rib 29 are in contact with the outer peripheral surface 27 of the feed roller 8 at positions separated from each other. Thereby, it is easy to make the contact pressure of the first guide rib 291 and the contact pressure of the second guide rib 292 on the outer peripheral surface 27 uniform. Also, the contact posture of the guide rib 29 with respect to the outer peripheral surface 27 is stabilized. (6) Further, in the present embodiment, the first guide rib 291 and the second guide rib 292 are arranged symmetrically with respect to the center C in the direction intersecting the feed direction F. By this symmetrical arrangement, the balance of the contact positions 38 of the outer peripheral surface 27 of the feed roller 8 and the first guide rib 291 and the second guide rib 292 is improved, and it is possible to effectively suppress the inclination of the direction of the feed force of the feed roller 8. (7) Further, in the present embodiment, the first guide rib 291 and the second guide rib 292 are in contact with the outer peripheral surface 27 at the positions of both ends P1 and P2 of the feed roller 8. Thereby, the occurrence of skew can be effectively suppressed.

[0042] 〔Other Embodiments〕 The medium feeding device 23 and the image reading device 1 according to the present invention are basically configured as described in the above-described embodiments, but it is of course possible to make partial configuration changes, omissions, etc. without departing from the gist of the present invention. In the above-described embodiment, the guide rib 29 has been described as being composed of two ribs, i.e., the first guide rib 291 and the second guide rib 292, but the number is not limited to two. It may be one or three or more. When there is one rib, from the viewpoint of ensuring the "displacement following", it is preferable to make the contact portion 28 have a planar shape and increase the contact area as much as possible within the possible range. The medium feeding device 23 can be mounted on devices other than the image reading device 1, and can also be mounted on a recording device such as an inkjet printer for use.

Explanation of Reference Numerals

[0043] 1... Image reading device, 2... Medium, 4... Conveying path, 5... First conveying roller, 6... Second conveying roller, 7... Placement portion, 8... Feeding roller, 9... First nip position, 10... Second nip position, 11... Rotation axis, 12... Rotation axis, 13... Rotation axis, 14... Rotation axis, 15... Separation roller, 16... Rotation axis, 17... Rotation axis, 18... Conveying path, 19... Curved inversion path, 20... Intermediate roller pair, 21... Discharge roller pair, 22... Nip position, 23... Medium feeding device, 24... Guide portion, 25... Support portion, 26... Shaft body portion, 27... Outer peripheral surface, 28... Contact portion, 29... Guide rib, 30... Elastic force generating portion, 31... Reading portion, 32... Reading portion, 33... Fulcrum, 36... Base plate portion, 37... Long hole, 38... Contact position, 40... Torsion coil spring, 41... One elastic piece, 42... L-shaped locking portion, 43... The other elastic piece, 44... Protrusion, 45... Hole, 50... Protrusion, 51... Upper first conveying roller, 52... Lower first conveying roller, 61... Upper second conveying roller, 62... Lower second conveying roller, 261... Base portion, 262... Shaft portion, 263... Shaft portion, 291... First guide rib, 292... Second guide rib, 341... Shaft hole. 342... Shaft hole, 351... Bearing portion, 352... Bearing portion, C... Center, central, F... Conveying direction, feeding direction

Claims

1. A feed roller for feeding a medium placed on a placement portion in a feed direction, a separation portion disposed opposite to the feed roller and nipping with the feed roller to separate the medium, a guide portion for guiding the medium toward the feed roller, and a support portion for supporting the guide portion, and the guide portion has a shaft body portion extending in a direction intersecting the feed direction of the medium, a guide rib extending from the shaft body portion in the feed direction to guide the medium toward the feed roller and having a contact portion contacting the outer peripheral surface of the feed roller, and an elastic force generating portion for generating an elastic force for pressing the contact portion in a direction of contacting the outer peripheral surface, and the guide portion is supported by the support portion so as to be capable of posture displacement following the posture of the outer peripheral surface in a state where the contact portion is in contact with the outer peripheral surface, A medium feeding device characterized by the above.

2. The medium feeding device according to claim 1, wherein the support portion has a fulcrum for swingably supporting the shaft body portion, and a bearing portion having shaft holes for pivotally supporting both ends of the shaft body portion, and the shaft holes are long holes that are long in a direction allowing displacement of the posture of the guide portion, A medium feeding device characterized by the above.

3. The medium feeding device according to claim 2, wherein the fulcrum is located at the center in the extending direction of the shaft body portion, A medium feeding device characterized by the above.

4. The medium feeding device according to claim 1, wherein a contact position of the contact portion with the outer peripheral surface is upstream of the nip position of the feed roller and the separation portion in the feed direction, A medium feeding device characterized by the above.

5. The medium feeding device according to claim 1, wherein the guide rib has a first guide rib, and a second guide rib located away from the first guide rib in a direction intersecting the feed direction, A medium feeding device characterized by the above.

6. The medium feeding device according to claim 5, wherein the first guide rib and the second guide rib are arranged symmetrically with respect to the center in a direction intersecting the feed direction of the feed roller, A medium feeding device characterized by the above.

7. The medium feeding device according to claim 6, wherein the first guide rib and the second guide rib contact the outer peripheral surface at positions at both ends in a direction intersecting the feed direction of the feed roller, A medium feeding device characterized by the above.

8. The medium feeding device according to any one of claims 1 to 7, and An image reading unit that reads an image of the medium, and An image reading apparatus characterized by the above.

Images