JP2017071484A - Media feeding device and image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce or avoid the possibility of double feeding of sheets by feeding rollers separating a plurality of sheets by separation rollers and feeding the plurality of sheets and to appropriately transport the sheets.SOLUTION: A media feeding device comprises: a media placing section 22 having a media placing surface 22a on which a plurality of media P is placed and constituting a transportation path of the plurality of media P; feeding rollers 28 feeding the media P by rotating while being brought into contact with each surface facing the media placing surface 22a of the media P; and separation rollers 30 nipping and separating the media P among the feeding rollers 28 and the separation rollers 30. A rotation shaft 42 of the separation rollers 30 is biased toward the feeding rollers 28 by a first biasing member 46 while being provided in a displaceable manner in a back and forth direction with respect to the feeding rollers 28. A rotation shaft 50 of the feeding rollers 28 is biased toward the separation rollers 30 by a second biasing member 54 while being provided in the displaceable manner in a back and forth direction with respect to the separation rollers 30. The feeding rollers 28 are displaced following displacement of the separation rollers 30.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a medium feeding device that conveys a medium, and an image reading apparatus including the medium feeding device.

  A scanner which is an example of an image reading apparatus is provided with an automatic document feeder (also called ADF (Auto Document Feeder)) as a medium, and is configured to automatically feed and read a plurality of documents. There is a case. As a configuration of such an automatic document feeder, as shown in Patent Document 1, a feeding roller that feeds the document by rotating in contact with the surface of the document set on a tray on which the document is placed. (Pick roller in Patent Document 1) and a separator that is pressed by a spring or the like toward the feeding roller and nips the document between the feeding roller and separates a plurality of documents into one sheet And a roller (brake roller in Patent Document 1).

  The feeding roller is configured to feed a sheet bundle (a plurality of documents) stacked on a tray in order from a lower sheet, that is, a sheet on a tray mounting surface side, and the separation roller includes: Damming sheets other than the first sheet from the bottom of the sheet bundle (the second sheet from the bottom) are dammed, and the first sheet from the bottom of the sheet bundle is nipped between the feeding roller and the separation roller, and downstream It is conveyed to the side.

JP 2014-136644 A

  By the way, a downstream side conveyance roller that further conveys the sheet separated and fed by the separation roller toward the image reading unit of the scanner may be provided on the downstream side of the feeding roller. . The sheet conveying speed of the downstream conveying roller is set to be faster than the sheet conveying speed of the feeding roller, and the sheet P is conveyed in a stretched state. FIG. 10 shows a schematic diagram of such a medium feeding device according to the prior art.

Here, as shown in FIG. 10, when the nip position 84 between the feeding roller 82 and the separation roller 80 is in a position where the sheet is pressed against the conveyance path 86 on the lower side (−Z direction) on the downstream side of the separation roller 80. When the leading edge of the paper P is sandwiched between the downstream transport roller pair 90, a force is applied to the separation roller 80 in the direction away from the feed roller 82 (+ Z direction) due to the reaction force due to the rigidity of the paper P. There is. In particular, when the stiffness of the paper is strong (high rigidity), the reaction force becomes large.
Then, the separation roller 80 is pushed up against the pressing force of the spring 88 by the reaction force due to the rigidity of the paper P, so that the paper easily enters between the feeding roller 82 and the separation roller 80, and the paper bundle The second and subsequent sheets from the bottom are not dammed up and the possibility of being double fed increases. In addition, in FIG. 10, the separation roller 80 shown with a dotted line has shown the state by which the separation roller 80 was pushed up.

  In view of the above problems, an object of the present invention is to reduce or avoid the possibility of double feeding of paper by a feeding roller that separates and feeds a plurality of papers by a separation roller, and to appropriately feed paper. is there.

  In order to solve the above-described problem, the medium feeding device according to the first aspect of the present invention has a medium mounting surface on which a plurality of media are mounted, and a medium mounting unit that configures the medium transport path A feeding roller that feeds the medium by rotating while contacting a surface of the medium placed on the medium placing surface, the surface facing the medium placing surface; and the feeding roller; And a separation roller that nips and separates the medium between them, and a rotation shaft of the separation roller is provided so as to be displaceable in a direction to advance and retreat with respect to the feeding roller, and a first urging member And the rotation axis of the feed roller is provided so as to be displaceable in a direction to advance and retreat with respect to the separation roller, and the second biasing member causes the separation roller to move toward the feeding roller. Urged toward the feed b Ra is a structure which is displaced following the displacement of the separating roller, characterized in that.

According to this aspect, since the feeding roller is displaced following the displacing separation roller, the possibility that the separation roller and the feeding roller are separated can be reduced.
As a result, a stable nip between the feeding roller and the separation roller can be secured, thereby reducing or avoiding the possibility of double feeding of the medium, and feeding the medium appropriately.

  The medium feeding device according to a second aspect of the present invention includes, in the first aspect, a pair of conveyance rollers that convey the medium on the downstream side of the feeding roller and the separation roller, and the rotation of the separation roller. The shaft is positioned downstream of the rotation shaft of the feeding roller, and the biasing force of the first biasing member is such that the second medium having higher rigidity than the first medium is When receiving the feeding force from both of the feeding rollers, the second medium is allowed to be displaced toward the separation roller, and the first medium is fed from both the transport roller pair and the feeding roller. When receiving the feeding force, the first medium is set to a size that does not allow displacement of the first medium toward the separation roller.

  When the rotation shaft of the separation roller is positioned downstream of the rotation shaft of the feeding roller, the medium is conveyed so as to be pressed against the medium guide member on the feeding roller side on the downstream side of the separation roller. The When the medium is transported in this way, when the leading edge of the medium to be fed is nipped by the pair of transport rollers, a reaction force due to the rigidity of the medium may be applied in the direction in which the separation roller is lifted. The reaction force based on the rigidity of the medium becomes larger as the medium (for example, cardboard) having higher rigidity.

  Here, when the urging force of the first urging member is increased, the separation roller is prevented from being lifted by a reaction force based on the rigidity of the medium, but the urging force of the separation roller to the feeding roller is large. If it is too high, it may be difficult to appropriately convey a medium having low rigidity (such as thin paper).

  According to this aspect, when the medium is a first medium having low rigidity when the medium receives a feeding force from both the transport roller pair and the feeding roller, When the separation roller does not float due to a reaction force based on rigidity, and the medium is a second medium having high rigidity, the separation roller is combined with the feeding roller by a reaction force based on the rigidity of the second medium. Since appropriate separation can be performed by displacing upward, it is possible to achieve both proper feeding of the first medium having low rigidity and the second medium having high rigidity.

  In the medium feeding device according to a third aspect of the present invention, in the second aspect, the medium conveying speed by the pair of conveying rollers is higher than the medium conveying speed by the feeding roller. And

When the medium fed by the feeding roller and the separation roller is at a position where the medium is pressed against the medium guide member on the feeding roller side, the conveyance speed of the medium by the conveyance roller pair is determined by the feeding roller. When the speed is higher than the conveyance speed of the medium, the reaction force due to the rigidity of the medium is more likely to be applied in the direction in which the separation roller is lifted.
According to this aspect, in the medium feeding device having such a configuration, the same effect as that of the second aspect is achieved, and appropriate feeding of the first medium having low rigidity and the second medium having high rigidity is compatible. It becomes possible.

  The medium feeding device according to a fourth aspect of the present invention is the medium feeding device according to any one of the first to third aspects, wherein the means for transmitting the power of the driving source for rotating the rotating shaft to the rotating shaft is a belt. It is based on a drive mechanism.

  When the feeding roller is displaced following the displacement of the separation roller, the rotating shaft is also displaced. According to this aspect, the structure which transmits the motive power of a drive source to the rotating shaft which displaces can be implement | achieved easily.

  A medium feeding device according to a fifth aspect of the present invention provides the medium feeding device according to any one of the first to fourth aspects, wherein the bearing is configured to restrict movement of the rotating shaft in the biasing direction by the second biasing member. And the bearing portion is formed integrally with the medium placement portion.

  According to this aspect, the movement amount of the feeding roller in the direction approaching the separation roller can be regulated with high accuracy with respect to the medium placement surface. Accordingly, the feeding roller can be prevented from protruding more than a predetermined amount with respect to the medium placement surface.

  A medium feeding device according to a sixth aspect of the present invention is the medium feeding device according to any one of the first to fifth aspects, provided on the upstream side in the medium conveying direction of the feeding roller and mounted on the medium placing surface. An upstream feeding roller is provided that picks up the placed medium and sends it to the feeding roller.

  According to this aspect, since the medium picked up by the upstream-side feeding roller is fed toward the feeding roller, the medium is efficiently fed, and the medium is more reliably separated by the separation roller. It can be carried out.

  A medium feeding device according to a seventh aspect of the present invention includes a medium placement surface on which a plurality of media are placed, a medium placement portion that constitutes a transport path of the medium, and the medium placement surface By rotating while contacting the surface of the medium placed on the surface facing the medium placing surface, the medium is nipped between the feeding roller that feeds the medium and the feeding roller. A separation roller that separates the rotation axis of the separation roller, the rotation shaft of the separation roller is located downstream of the rotation shaft of the feeding roller, and the position of the separation roller is fixed, A rotation shaft is provided so as to be displaceable in a direction to advance and retreat with respect to the separation roller, and is urged toward the separation roller by an urging member, and the feeding roller resists the urging force of the urging member. And away from the separation roller Displaceably it is configured, characterized in that.

As described above, when the rotation shaft of the separation roller is located downstream of the rotation shaft of the feeding roller, the medium is pressed against the medium guide member on the feeding roller side on the downstream side of the separation roller. So that it is conveyed. When the medium is transported in this way, when the rigidity of the medium is high, a reaction force due to the rigidity of the medium may be applied in the direction in which the separation roller is lifted.
According to this aspect, since the separation roller is fixed, it is possible to avoid a possibility that a gap is generated in the nip portion with the feeding roller by displacing the separation roller in the lifting direction.

  An image reading apparatus according to an eighth aspect of the present invention is a medium feeding device according to any one of the first to seventh aspects, wherein a reading unit that reads a medium and the medium is fed toward the reading unit. And a device.

  According to this aspect, in the image reading apparatus including the reading unit that reads the medium, when the medium is fed toward the reading unit, the same effect as any one of the first to seventh aspects. Is obtained.

1 is an external perspective view showing a scanner according to the present invention. FIG. 5 is a perspective view showing a feeding state in the scanner according to the invention. The perspective view at the time of making an upper unit open with respect to the lower unit in the scanner which concerns on this invention. FIG. 4 is a side sectional view showing a feeding path in the scanner according to the invention. 1 is a perspective view showing a medium feeding device according to the present invention. 1 is a schematic diagram of a medium feeding device according to the present invention. The figure explaining operation | movement of the medium feeding apparatus which concerns on this invention. The figure explaining operation | movement of the medium feeding apparatus which concerns on this invention. Schematic which shows the other example of the medium feeding apparatus which concerns on this invention. The figure explaining a prior art.

[Example 1]
First, an outline of an image reading apparatus including a medium feeding device according to an embodiment of the present invention will be described. As an example of the image reading apparatus of the present embodiment, a document scanner (hereinafter simply referred to as a scanner 10) capable of reading at least one of the front surface and the back surface of a medium is given as an example.
FIG. 1 is an external perspective view showing a scanner according to the present invention. FIG. 2 is a perspective view showing a feeding state in the scanner according to the present invention. FIG. 3 is a perspective view of the scanner according to the present invention when the upper unit is opened with respect to the lower unit. FIG. 4 is a side sectional view showing a feeding path in the scanner according to the present invention. FIG. 5 is a perspective view showing a medium feeding device according to the present invention. FIG. 6 is a schematic view of a medium feeding device according to the present invention. 7 and 8 are diagrams for explaining the operation of the medium feeding device according to the present invention.

<Overview of the scanner>
As shown in FIG. 1, a scanner 10 as an image reading apparatus according to the present invention includes a lower unit 12, an upper unit 14, a paper support 16, and a paper discharge tray 18.

In the XYZ coordinate system shown in each drawing, the X direction is the apparatus width direction, the paper width direction, and the Y direction is the paper transport direction. The Z direction is a direction that intersects the Y direction, and generally indicates a direction that is orthogonal to the surface of the sheet being conveyed. Further, the + Y direction side is the front side of the apparatus, and the −Y direction side is the back side of the apparatus. Also, the right side when viewed from the front side of the apparatus is the + X direction, and the left side is the −X direction. Further, the + Z direction is the upper side of the apparatus (including the upper and upper surfaces), and the −Z direction side is the lower side of the apparatus (including the lower and lower surfaces).
Further, in the scanner 10, the paper P as a medium is transported in the + Y direction in each drawing. In the following, the direction in which the paper P is conveyed (+ Y direction side) is referred to as “downstream”, and the opposite direction (−Y direction side) is referred to as “upstream”.

  The upper unit 14 is attached to the lower unit 12 so as to be rotatable with respect to the lower unit 12 with the downstream side in the sheet conveying direction as a rotation fulcrum. The upper unit 14 is closed with respect to the lower unit 12 and constitutes a paper transport path for the paper P together with the lower unit 12 (see FIG. 2), and is rotated to the front side of the apparatus with respect to the lower unit 12 to form It is possible to assume an open state (see FIG. 3) in which the paper jam path of the paper P can be easily performed by exposing the P paper transport path.

Further, a paper support 16 that opens and closes the upper portion of the upper unit 14 is provided.
The paper support 16 is attached to the lower unit 12 so as to be rotatable with respect to the upper part on the back side of the lower unit 12. As shown in FIG. 1, the paper support 16 is in a non-feeding state that covers the upper portion of the upper unit 14 and the feeding port 20 (FIG. 2), and from the non-feeding state in FIG. The paper feed port 20 is opened, and the back surface (support surface 16a described later) of the paper support 16 can be in a feed state in which the paper P is connected to the medium placement portion 22.

  Further, a discharge port 24 for discharging the paper P is provided on the front side of the lower unit 12. Further, the lower unit 12 includes a paper discharge tray 18 that can be pulled out from the discharge port 24 toward the front side of the apparatus. The paper discharge tray 18 can be in a state of being housed in the bottom of the lower unit 12 (see FIG. 1) and in a state of being pulled out to the front side of the apparatus (see FIG. 2). Further, in the present embodiment, the paper discharge tray 18 is configured by connecting a plurality of tray members, and the pull-out length from the discharge port 24 can be adjusted according to the length of the paper P to be discharged.

<About the feeding route in the scanner>
Next, a sheet conveyance path in the scanner 10 will be described with reference to FIG.
The front end side (downstream side) of the paper P set in the feeding port 20 is supported by the medium placement surface 22 a of the medium placement portion 22, and the rear end side (upstream side) of the paper P is set to the lower unit 12. The paper support 16 in a posture rotated to the back side is supported and placed by the support surface 16a which is the back side. A plurality of sheets P can be set in the feeding port 20.

  A plurality of sheets P set in the feeding port 20 are fed by the medium feeding device 25 and sent toward an image reading unit 34 described later. The medium feeding device 25 according to the present embodiment includes a first feeding roller 26, a second feeding roller 28, a separation roller 30, and a transport roller pair 32. The medium feeding device 25 will be described below.

The paper P placed on the medium placement unit 22 is fed by a first feed roller 26 as an “upstream feed roller” provided rotatably with respect to the lower unit 12 on which the medium placement unit 22 is provided. Picked up and fed downstream (+ Y direction side). Specifically, the sheet P is fed toward the downstream side by rotating the first feeding roller 26 in contact with the surface of the sheet P facing the medium placement surface 22a. Accordingly, when a plurality of sheets P are set in the feeding port 20 in the scanner 10, the sheets are fed in order from the sheet P on the medium placement surface 22 a side of the medium placement unit 22 toward the downstream side.
The first feeding roller 26 is disposed so that a part thereof protrudes from the medium placement surface 22a of the medium placement portion 22 (see FIG. 5).

The medium stacking unit 22 supports the paper P set in the feeding port 20 on the upstream side of the first feeding roller 26, and the first feeding roller on the downstream side of the first feeding roller 26. It plays a role as a conveyance path of the paper P fed by the feeding roller 26.
Further, at a position facing the first feeding roller 26, a paper returning member 27 urged toward the first feeding roller 26 by a pressing spring 29 (see FIG. 5) is provided. Is suppressed.

On the downstream side of the first feeding roller 26, a second feeding roller 28 as a “feeding roller” is rotatably provided in the lower unit 12, and a separation roller 30 is rotatably provided in the upper unit 14. Yes.
Similarly to the first feeding roller 26, the second feeding roller 28 is disposed so that a part of the second feeding roller 28 protrudes from the medium placement surface 22 a of the medium placement portion 22 (see FIG. 5). The sheet P is fed toward the downstream side by rotating while being in contact with the surface facing the medium placement surface 22a.

In the present embodiment, the separation roller 30 is given a predetermined rotational resistance. When two or more sheets P are fed by the first feeding roller 26, only the sheet P separated by the separation roller 30 and in contact with the second feeding roller 28 is the second feeding roller. 28 and the separation roller 30 and is fed downstream in the feeding direction.
The configurations and operations of the second feeding roller 28 and the separation roller 30 will be described in detail later.

  A transport roller pair 32, an image reading unit 34 as a “reading unit”, and a discharge roller pair 36 are provided on the downstream side of the second feeding roller 28 in the transport direction. The sheet P that is nipped by the second feeding roller 28 and the separation roller 30 and fed downstream in the conveyance direction is nipped by the conveyance roller pair 32 and is fed to the image reading unit 34 that is located downstream of the conveyance roller pair 32. Be transported.

  The conveyance roller pair 32 includes a conveyance driving roller 32 a provided in the lower unit 12 and a conveyance driven roller 32 b provided in the upper unit 14 and rotated following the conveyance driving roller 32 a. In the present embodiment, the conveyance speed of the paper P by the conveyance roller pair 32 is set to be higher than the conveyance speed of the paper P by the second feeding roller 28. As a result, when the paper P is sandwiched by the transport roller pair 32, the paper P is in a tensioned state, and the paper P can be stably transported.

  The image reading unit 34 includes an upper image reading sensor 38 provided on the upper unit 14 side and a lower image reading sensor 40 provided on the lower unit 12 side. In the present embodiment, the upper image reading sensor 38 and the lower image reading sensor 40 are configured as a contact image sensor module (CISM) as an example.

  After the image P is read by the image reading unit 34 at least one of the front and back surfaces of the paper P, the sheet P is nipped by a discharge roller pair 36 located downstream in the transport direction of the image reading unit 34 and discharged. The sheet is discharged from 24 toward the sheet discharge tray 18. Note that the alternate long and short dash line in FIG.

  In the present embodiment, the discharge roller pair 36 includes a discharge drive roller 36a provided in the lower unit 12 and a discharge driven roller 36b provided in the upper unit 14 and driven to rotate relative to the discharge drive roller 36a.

  In the present embodiment, the first feed roller 26, the second feed roller 28, the transport drive roller 32a, and the discharge drive roller 36a are rotated by at least one drive source (not shown) provided in the lower unit 12. Driven.

<About the configuration of the second feeding roller and separation roller>
Next, the configuration of the second feeding roller 28 and the separation roller 30 will be described with reference to FIGS.
As shown in FIG. 5, the separation roller 30 has a rotation shaft 42 provided in a roller holder 44. The roller holder 44 rotates around a fulcrum 48 (FIG. 6), and the rotation shaft 42 is displaced in a direction to advance and retreat with respect to the second feeding roller 28, so that the separation roller 30 is moved to the second feeding roller 28. It is configured to move forward and backward.

  The roller holder 44 is provided with a first compression spring 46 as a “first urging member”, and the rotating shaft 42 is urged by the first compression spring 46 via the roller holder 44. The separation roller 30 is urged toward the second feeding roller 28 with a predetermined urging force. The urging force of the first compression spring 46 will be described later.

  The second feeding roller 28 is pivotally supported on the rotation shaft 50, and the rotation shaft 50 is provided on the bearing portion 52. The rotation shaft 50 of the second feeding roller 28 is provided so as to be displaceable in a direction that advances and retreats with respect to the separation roller 30. The second compression spring 54 as a “second urging member” serves as the separation roller 30. It is energized towards.

  The bearing portion 52 is configured to restrict movement of the rotating shaft 50 in a biasing direction (+ Z direction in FIG. 5) by the second compression spring 54 beyond a predetermined amount. The urging force of the second compression spring 54 is set according to the urging force of the first compression spring 46, and the rotating shaft 50 in the non-feed state of the paper P is applied to the bearing portion 52 by the second compression spring 54. It is supported with a space 53 (FIG. 6) that allows movement in the urging direction. As a result, when the separation roller 30 is displaced in the direction away from the second feeding roller 28 (+ Z direction), the rotary shaft 50 can be displaced in the + Z direction following the displacement. That is, the second feeding roller 28 is displaced following the displacement of the separation roller 30.

Further, the effects of the present invention will be described with specific examples.
As shown in FIG. 6, in the present embodiment, the rotation shaft 42 of the separation roller 30 is located on the downstream side of the rotation shaft 50 of the second feeding roller 28. Therefore, the contact position of the separation roller 30 with respect to the second feeding roller 28, that is, the nip portion 62 between the separation roller 30 and the second feeding roller 28, causes the sheet P to be fed second on the downstream side in the transport direction of the separation roller 30. It is in a position to press against the medium guide member 60a side on the roller 28 side (see FIG. 7). The medium guide members 60a and 60b are members constituting the transport path of the paper P, and are provided on the second feeding roller 28 side (lower side) and the separation roller 30 side (upper side), respectively.
When the sheet P is not sandwiched between the nip portions 62 of the separation roller 30 and the second feeding roller 28, the separation roller 30 rotates together with the rotation of the second feeding roller 28.

  When a plurality of sheets P are fed to the nip portion 62 of the separation roller 30 and the second feeding roller 28, the first sheet P1 from the bottom passes through the nip portion 62 as shown in FIG. However, the resistance (hindering force) of the separation roller 30 exceeds the force of the second and subsequent sheets P2 and P3 as the first sheet P1 is conveyed, and the sheet P2 Block P3.

The paper P1 that has passed the nip portion 62 is sent, and the leading edge thereof is nipped by the transport roller pair 32, and further sent downstream by the transport force of the transport roller pair 32 (FIG. 8).
Here, as described above, when the transport speed of the paper P by the transport roller pair 32 is set higher than the transport speed of the paper P by the second feeding roller 28, the paper P is sandwiched between the transport roller pair 32. At this time, the paper P is stretched between the nip portion 62 of the separation roller 30 and the second feeding roller 28 and the nip portion 64 of the transport roller pair 32.

At this time, the reaction force due to the rigidity of the paper P is applied in the direction in which the separation roller 30 is lifted (+ Z direction). The reaction force based on the rigidity of the paper P increases as the rigidity of the paper increases.
For this reason, when a sheet having high rigidity is conveyed, the separation roller 30 may be displaced in the + Z direction.

In the present embodiment, since the second feeding roller 28 is displaced following the displacing separation roller 30 (see FIG. 8), the separation roller 30 and the second feeding roller 28 (nip distance) may be separated. Can be reduced. As a result, a stable nip between the second feeding roller 28 and the separation roller 30 can be secured, and feeding can be appropriately performed while reducing or avoiding the possibility of double feeding of the paper P.
In FIG. 8, the positions before displacement of the separation roller 30 and the second feeding roller 28 are indicated by dotted lines.

  Next, the biasing force of the first compression spring 46 will be described. If the urging force of the first compression spring 46 is increased, the lifting of the separation roller 30 due to the reaction force based on the rigidity of the paper P is suppressed, but if the urging force of the separation roller 30 to the second feeding roller 28 is too large, There are cases where it is difficult (for example, non-feeding) to properly transport a sheet of low rigidity (such as thin paper).

  In the present embodiment, the urging force of the first compression spring 46 is such that the second medium is applied to a sheet having a low rigidity (hereinafter referred to as a first medium) and a sheet having a higher rigidity (hereinafter referred to as a second medium). When receiving feed force from both the transport roller pair 32 and the second feed roller 28, the second medium is allowed to displace to the separation roller 30 side, and the first medium is transported to the transport roller pair 32 and the second feed roller. When receiving a feeding force from both the feeding roller 28, the first medium is set to a size that does not allow displacement of the first medium toward the separation roller 30 side.

  In other words, when the paper P receives a feeding force from both the transport roller pair 32 and the second feeding roller 28, and the paper P is a first medium with low rigidity, the paper P (first medium) ) Due to the reaction force based on the rigidity of the sheet P, the separation roller 30 is not displaced upward, and the sheet P is the second medium having a high rigidity. The roller 30 is displaced upward together with the second feeding roller 28. This makes it possible to achieve both appropriate feeding of the first medium with low rigidity and the second medium with high rigidity.

  In this embodiment, a belt drive mechanism 58 is used as a transmission means for transmitting the power of the drive source 56 that rotates the rotary shaft 50 to the rotary shaft 50. By using the belt drive mechanism 58 to transmit power from the drive source 56 to the rotary shaft 50, a configuration for transmitting the power of the drive source 56 to the rotating shaft 50 that is displaced can be easily realized. In addition, it is also possible to use another mechanism, for example, a drive mechanism using a gear (gear) as the transmission means.

In the present embodiment, the bearing portion 52 is integrally formed with the medium placement portion 22. Since the bearing portion 52 is integrated with the medium placement portion 22, the amount of movement of the second feeding roller 28 in the direction approaching the separation roller 30 can be regulated with respect to the medium placement surface 22a with high accuracy. it can. Accordingly, it is possible to suppress the second feeding roller 28 from protruding beyond a predetermined amount with respect to the medium placement surface 22a.
Of course, the bearing portion 52 can be provided separately from the medium placement portion 22.

  In the present embodiment, the separation roller 30 and the second feeding roller 28 are provided at a predetermined interval in the apparatus width direction (X-axis direction) in the medium placement unit 22. Similarly, two first feeding rollers 26 are also provided at a predetermined interval in the apparatus width direction in the medium loading unit 22. The separation roller 30, the second feeding roller 28, and the first feeding roller 26 may be a single roller provided at the center in the apparatus width direction of the medium placement unit 22.

  In addition, the present invention can be applied to a medium feeding device having a configuration in which the first feeding roller 26 is not provided. In the present embodiment, since the paper P is picked up by the first feeding roller 26 and sent to the second feeding roller 28, the paper P is efficiently fed and the separation roller 30 can more reliably separate the paper P. Can be done.

[Example 2]
In the second embodiment, another example of the medium feeding device will be described with reference to FIG.
FIG. 9 is a schematic view showing another example of the medium feeding device according to the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components is omitted.

In the present embodiment, the separation roller 70 is fixed, and the rotation shaft 74 of the second feeding roller 72 is urged in the + Z direction by a compression spring 76 as an urging member and provided in the bearing portion 78. Yes. The separation roller 70 is rotatably fixed by the rotation shaft 71 being fixed to the upper unit 14 (see FIG. 4).
On the other hand, the second feeding roller 72 is configured to be displaceable in a direction against the urging force of the compression spring 76 (−Z direction).

  Also in the present embodiment, as in Example 1, the contact position of the separation roller 70 with respect to the second feeding roller 72, that is, the nip portion 79 places the paper P on the second feeding roller 72 side on the downstream side of the separation roller 70. It is in the position pressed against the medium guide member 60a. Accordingly, when the rigidity of the paper P is high, the reaction force due to the rigidity of the paper P is applied in the direction in which the separation roller 70 is lifted when the leading edge of the paper P is nipped by the conveyance roller pair 32.

  However, in this embodiment, since the separation roller 70 is fixed, the separation roller 70 is not displaced. Accordingly, it is possible to avoid a possibility that a gap is generated in the nip portion 79 with the feeding roller due to the separation roller 70 being displaced.

  The rotation shaft 74 in the non-feeding state of the paper P is restricted by the bearing portion 78 from moving in the urging direction (Z direction) by the compression spring 76. By forming the bearing portion 78 integrally with the medium placement portion 22, the position of the rotation shaft 74 with respect to the medium placement surface 22a can be positioned with high accuracy. Accordingly, the second feeding roller 72 can be arranged with high accuracy with respect to the medium placement surface 22a.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

10 ... Scanner (image reading device), 12 ... Lower unit, 14 ... Upper unit,
16 ... paper support, 16a ... support surface, 18 ... discharge tray, 20 ... feed port,
22 ... Medium placement unit, 22a ... Medium placement surface, 24 ... Discharge port, 25 ... Medium feeding device,
26 ... 1st feeding roller, 27 ... Paper return member, 28 ... 2nd feeding roller,
29 ... Presser spring, 30 ... Separation roller, 32 ... Conveying roller pair,
32a ... conveyance drive roller, 32b ... conveyance driven roller,
34: Image reading unit, 36: Discharge roller pair, 36a: Discharge drive roller,
36b ... discharge driven roller, 38 ... upper image reading sensor, 40 ... lower image reading sensor,
42 ... rotating shaft, 44 ... roller holder, 46 ... first compression spring, 48 ... fulcrum,
50 ... Rotating shaft, 52 ... Bearing part, 54 ... Second compression spring, 56 ... Drive source,
58 ... Belt drive mechanism, 60a, 60b ... Medium guide member, 62 ... Nip part,
64 ... nip part, 70 ... separation roller, 72 ... second feed roller,
74 ... Rotating shaft, 76 ... Compression spring, 78 ... Bearing part, 79 ... Nip part,
P ... paper

Claims (8)

A medium placement section having a medium placement surface on which a plurality of media are placed, and constituting a transport path of the medium;
A feeding roller that feeds the medium by rotating while contacting a surface of the medium placed on the medium placing surface and facing the medium placing surface;
A separation roller that nips and separates the medium from the feeding roller, and
The rotating shaft of the separation roller is provided so as to be displaceable in a direction to advance and retreat with respect to the feeding roller, and is biased toward the feeding roller by the first biasing member,
A rotation shaft of the feeding roller is provided so as to be displaceable in a direction to advance and retreat with respect to the separation roller, and is biased toward the separation roller by a second biasing member, and the feeding roller is It is configured to follow and follow the displacement of the separation roller.
A medium feeding device. The medium feeding device according to claim 1, further comprising a pair of conveying rollers that conveys the medium on a downstream side of the feeding roller and the separation roller,
The rotation axis of the separation roller is located downstream of the rotation axis of the feeding roller;
The biasing force of the first biasing member is such that when the second medium having higher rigidity than the first medium receives a feeding force from both the pair of transport rollers and the feeding roller, the second medium When the first medium receives a feeding force from both the transport roller pair and the feeding roller, the first medium is displaced toward the separation roller. Is set to a size that does not allow
A medium feeding device. The medium feeding device according to claim 2, wherein
The medium feeding apparatus according to claim 1, wherein a conveyance speed of the medium by the conveyance roller pair is higher than a conveyance speed of the medium by the feeding roller.   4. The medium feeding device according to claim 1, wherein the means for transmitting the power of the driving source for rotating the rotating shaft to the rotating shaft is a belt driving mechanism. 5. A medium feeding device characterized by the above. In the medium feeding apparatus according to any one of claims 1 to 4,
A bearing portion for restricting movement of the rotating shaft in the urging direction by the second urging member;
The medium feeding device, wherein the bearing portion is formed integrally with the medium placing portion. In the medium feeding device according to any one of claims 1 to 5,
An upstream feeding roller provided on the upstream side in the medium conveying direction of the feeding roller, and picking up the medium placed on the medium placement surface and sending it to the feeding roller;
A medium feeding device. A medium placement section having a medium placement surface on which a plurality of media are placed, and constituting a transport path of the medium;
A feeding roller that feeds the medium by rotating while contacting a surface of the medium placed on the medium placing surface and facing the medium placing surface;
A separation roller that nips and separates the medium from the feeding roller, and
The rotation axis of the separation roller is located downstream of the rotation axis of the feeding roller, and the position of the separation roller is fixed,
A rotation shaft of the feeding roller is provided so as to be displaceable in a direction to advance and retreat with respect to the separation roller and is biased toward the separation roller by a biasing member, and the feeding roller is biased to the biasing member It is configured to be displaceable in a direction away from the separation roller against the urging force of
A medium feeding device. A reading unit for reading a medium;
The medium feeding device according to any one of claims 1 to 7, wherein the medium is fed toward the reading unit.
An image reading apparatus.

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