JP2017061350A - Medium feeding device, image reading device, and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medium feeding device which properly separates greater variations of mediums, and to provide an image reading device including the medium feeding device and a recording device.SOLUTION: A script feeding device 3 included in an image reading device 1 includes: a cover part 6 serving as a placement part on which scripts are placed; a feeding roller 10 which feeds the scripts from the cover part 6; and a separation roller 11 which separates the scripts. The separation roller 11 is formed so as to adjust a position where the separation roller 11 contacts with the feeding roller 10. Thus, separation performance of the scripts can be adjusted without replacing device building elements such as the separation roller 11 or the feeding roller 10. Thus, the script feeding device 3 properly separates greater variations of scripts.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a medium feeding apparatus for feeding a medium, and an image reading apparatus and a recording apparatus including the medium feeding apparatus.

  Hereinafter, a scanner which is an example of an image reading apparatus will be described as an example. The scanner is provided with a feeding device (also called ADF (Auto Document Feeder)) that automatically feeds a document that is an example of a medium, and may be configured to automatically feed and read a plurality of documents. is there.

  As a configuration of such a feeding device, as shown in Patent Document 1, a tray on which a document is placed (“Shooter 14” in Patent Document 1) and a surface of the document set in the tray are brought into contact. And a separation roller for separating the document in contact with the feeding roller (“separation roller 12” in Patent Document 1). There is something with.

  The feeding roller described in Patent Document 1 is configured to sequentially feed a lower sheet, that is, a sheet on the tray mounting surface side, among a plurality of documents (sheet bundle) stacked on the tray. The upper sheet, that is, the sheet to be separated, comes into contact with the separation roller so that the downstream sheet is prevented from proceeding downstream.

Japanese Patent No. 4820314

  There are various types of originals, such as thick paper and thin paper, that is, those that are easy to separate depending on the type of medium and those that are difficult to separate. Also, depending on environmental conditions such as humidity, there are conditions that are easy to separate and conditions that are difficult to separate.

  On the other hand, the separation performance when separating the document with the separation roller and the feeding roller should be adjusted under various conditions such as the material, hardness, surface condition of both rollers, and the pressing load of the separation roller against the feeding roller. Can do. On the other hand, if an appropriate separation condition is set for a certain document, the separation performance may be inferior for other types of documents. In other words, it is very difficult to set an appropriate separation condition for all the various documents, and depending on the document to be fed, double feeding or non-feeding may occur.

  Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a medium feeding device that can appropriately separate a larger number of types of media, and an image reading device and a recording device including the same. It is to provide.

  In order to solve the above problems, a medium feeding device according to a first aspect of the present invention includes a medium loading unit for loading a medium, a feeding roller for feeding the medium from the medium loading unit, and the feeding roller. A separation roller that separates the medium by nipping the medium with the feeding roller, and the separation roller is configured to be capable of adjusting a position in contact with the feeding roller.

  According to this aspect, since the medium feeding device including the feeding roller and the separation roller is configured to be able to adjust the position where the separation roller is in contact with the feeding roller, a device such as a separation roller or a feeding roller Separation performance can be adjusted without replacing the components. Thereby, it is possible to appropriately separate more types of media.

  According to a second aspect of the present invention, in the first aspect, the separation roller is configured to be capable of adjusting the position by swinging around a rotation axis center of the feeding roller. .

  According to this aspect, since the separation roller is configured to be able to adjust the position by swinging around the rotation axis center of the feeding roller, the distance between the separation roller and the feeding roller Can be maintained. An example of the effect obtained as a result will be described later.

  According to a third aspect of the present invention, in the first or second aspect, the separation roller is displaceable together with a path forming member that forms a feeding path for feeding a medium that forms the periphery of the separation roller. It is comprised by these.

  According to this aspect, the separation roller is configured to be displaceable together with the path forming member that forms the feeding path for feeding the medium, which forms the periphery of the separation roller, and thus displaces the separation roller. Therefore, it is not necessary to secure a space for the path forming member, and the medium can be guided appropriately by appropriately configuring the path forming member.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a drive source that displaces the separation roller and a control unit that controls the drive source are provided.
According to this aspect, since the drive source for displacing the separation roller and the control means for controlling the drive source are provided, the position adjustment of the separation roller can be automatically performed, and usability is improved.

  According to a fifth aspect of the present invention, in the fourth aspect, the apparatus includes a height detection unit that detects a stacking height of the medium placed on the medium placement unit, and the control unit includes the height detection unit. The separation roller is displaced according to the detection result.

  When the stacking height of the medium is high (when the number of set sheets of the medium is large) and when it is low (when the number of set sheets of the medium is small), the separation property of the medium is different. According to this aspect, the apparatus includes a height detection unit that detects a stacking height of the medium placed on the medium placement unit, and the control unit performs the separation roller according to a detection result of the height detection unit. Therefore, appropriate separation according to the stacking height of the medium can be performed.

  According to a sixth aspect of the present invention, in the fourth or fifth aspect, the control means displaces the separation roller in accordance with information about a medium input by a user.

  According to this aspect, the control unit displaces the separation roller in accordance with information about the medium input by the user. Therefore, by adjusting the position of the separation roller in accordance with the type of medium, the type of medium Appropriate separation can be performed according to the conditions.

  According to a seventh aspect of the present invention, in any one of the fourth to sixth aspects, a humidity detection unit that detects humidity is provided, and the control unit controls the separation roller according to a detection result of the humidity detection unit. Displaced.

  The separation property of the medium differs depending on whether the humidity is high or low. According to this aspect, it is provided with the humidity detection means for detecting the humidity, and the control means displaces the separation roller in accordance with the detection result of the humidity detection means, so that appropriate separation according to humidity can be performed. it can.

  According to an eighth aspect of the present invention, in any one of the fourth to seventh aspects, a double feed detection unit that detects a double feed of a medium is provided on the downstream side of the feed roller, and the control unit includes: The separation roller is displaced according to the detection result of the double feed detection means.

  According to this aspect, it is provided with the double feed detection means for detecting the double feed of the medium, and the control means displaces the separation roller according to the detection result of the double feed detection means. Accordingly, the separation performance can be appropriately maintained by displacing the separation roller.

  According to a ninth aspect of the present invention, in any one of the fourth to seventh aspects, a non-feed detection unit that detects non-feed of the medium is provided on the downstream side of the feed roller, and the control unit includes: The separation roller is displaced according to the detection result of the non-delivery detection means.

  According to this aspect, the non-feed detection means for detecting the double feed of the medium is provided, and the control means displaces the separation roller according to the detection result of the non-feed detection means. Accordingly, the separation performance can be appropriately maintained by displacing the separation roller.

  An image reading apparatus according to a tenth aspect of the present invention includes a reading unit that reads a medium, and a medium feeding device according to any one of the first to ninth aspects that feeds the medium toward the reading unit. , Provided.

  A recording apparatus according to an eleventh aspect of the present invention is a medium feeding apparatus according to any one of the first to ninth aspects, wherein the recording means performs recording on a medium and the medium is fed to the recording means side. And.

  According to the tenth aspect, in the image reading apparatus and according to the eleventh aspect, in the recording apparatus, it is possible to obtain the same effects as any of the first to ninth aspects described above. .

1 is a perspective view showing an external appearance of an image reading apparatus according to the present invention. 1 is a perspective view showing an external appearance of a state in which a cover part of an image reading apparatus according to the present invention is opened. FIG. 3 is a side cross-sectional view illustrating a sheet conveyance path of the image reading apparatus according to the present invention. FIG. 4 is an enlarged view of a document feeding unit in FIG. 3. The front view (partial block diagram) of the mechanism which displaces a separation roller. The flowchart which shows an example of the control which a control part performs. The front view which shows other embodiment of the mechanism which displaces a separation roller (partial block diagram).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. However, the invention is not limited to the embodiment described below, and various modifications are possible within the scope of the invention described in the claims. Assuming that these are also included in the scope of the present invention, one embodiment of the present invention will be described below.

  FIG. 1 is a perspective view showing an external appearance of an image reading apparatus 1 according to an embodiment of the present invention, FIG. 2 is a perspective view showing an external appearance of the image reading apparatus 1 in a state where a cover 6 is opened, and FIG. 3 is an image reading apparatus. FIG. 4 is an enlarged view of the document feeding unit in FIG. 3. FIG. 5 is a front view (partial block diagram) of a mechanism for displacing the separation roller 11, and FIG. 6 is a flowchart illustrating an example of control performed by the control unit 31. FIG. 7 is a front view (partially block diagram) showing another embodiment of a mechanism for displacing the separation roller 11.

  In the XYZ coordinate system shown in each drawing, the X direction is the apparatus width direction, the document width direction, the Y direction is the depth direction of the image reading apparatus and the document discharge direction, and the Z direction is orthogonal to the document discharge direction. Shows direction. In each figure, the + Y direction side is the front side of the apparatus, and the −Y direction side is the back side of the apparatus.

The overall configuration of the image reading apparatus 1 according to the present invention will be described below.
The image reading apparatus 1 is configured as a document scanner capable of reading at least one of the front surface and the back surface of a document to be read. The image reading apparatus 1 includes a document feeding device 3 (FIG. 3) which is an embodiment of a “medium feeding device” according to the present invention. The main body of the image reading apparatus 1 includes a lower unit 4, an upper unit 5, a cover unit 6, and a discharge tray 7.

  The upper unit 5 is provided so as to be rotatable about a rotation shaft (not shown) provided downstream of the lower unit 4 in the sheet conveyance direction. The upper unit 5 can take a closed state (FIGS. 1 to 5) that constitutes a document transport path with the lower unit 4 and an open state (not shown) that opens the document transport path by rotating. .

  A cover portion 6 is provided on the upper portion on the back side of the lower unit 4. The cover 6 is attached to the lower unit 4 so as to be rotatable. By rotating, the cover 6 switches between a closed state that covers the top of the upper unit 5 as shown in FIG. 1 and an open state that opens the top of the upper unit 5 as shown in FIG. The cover 6 constitutes a part of a document placing portion (medium placing portion) on which a document to be set is placed in the open state.

  Next, a document discharge port 8 for discharging the read document is provided on the front side of the apparatus. The lower unit 4 includes a discharge tray 7 that can be pulled out from the document discharge port 8 toward the front side of the apparatus. The discharge tray 7 can be in a state of being housed in the bottom of the lower unit 4 (see FIG. 1) and in a state of being pulled out to the front side of the apparatus (see FIG. 2). In this embodiment, the discharge tray 7 is configured by connecting a plurality of tray members.

Next, the sheet conveyance path in the image reading apparatus 1 will be described with reference to FIG. In FIG. 3 and subsequent figures, only the main components of the image reading device 1 and the document feeder 3 are shown, and the components unnecessary for the description are omitted. In FIG. 3, the lower unit 4 and the upper unit 5 show only the outline of the housing by phantom lines.
The document placed on the cover 6 in the opened state is fed to the downstream side in the feeding direction by a feeding roller 10 that is rotated by a motor that is a driving source (not shown). Sent. The outer peripheral surface of the feeding roller 10 is made of a high friction material (for example, rubber). Reference numeral 10 a is a rotation axis of the feeding roller 10.

  In FIG. 3, the symbol G indicates a placed document bundle. The front end of the original bundle G is held at a feeding standby position (position shown in FIG. 3) by a shutter (not shown), and entry of the original bundle between the feeding roller 10 and a separation roller 11 described later is restricted. Yes. The shutter is retracted when feeding is started, and the leading end of the document bundle G contacts the separation roller 11.

  A separation roller 11 is provided at a position facing the feeding roller 10. In the present embodiment, the separation roller 11 is provided in a state of being urged with respect to the feeding roller 10 by an urging means (not shown). The outer peripheral surface of the separation roller 11 is made of a high friction material (for example, rubber) in the same manner as the feeding roller 10. Reference numeral 11 a is a rotation shaft of the separation roller 11.

  Further, the separation roller 11 is provided with a torque limiter 9, and further, through this torque limiter 9, a rotation direction (clockwise in FIG. 3) for sending a document downstream from a torque supply means (not shown) or a driving source such as a motor. It is configured to receive a driving torque in a direction opposite to the rotation direction (counterclockwise direction in FIG. 3).

  In the above configuration, when the separation roller 11 is in direct contact with the feeding roller 10, the rotational torque received from the feeding roller 10 exceeds the limit torque of the torque limiter 9, so that the separation roller 11 rotates following the feeding roller 10. (Clockwise direction in FIG. 3).

Then, when the feeding of the original is started and a plurality of originals enter between the feeding roller 10 and the separation roller 11, the separation roller 11 does not receive the rotational torque from the feeding roller 10 and is driven by the feeding roller 10. Rotation stops. As a result, the upper document excluding the lowest document to be fed (the document that should be prevented from being double-fed) is not subjected to the transport force for proceeding to the downstream side, and the leading end is in contact with the separation roller 11 Cannot proceed downstream. As a result, double feeding of documents is prevented.
Since the lowest document to be fed is in direct contact with the feeding roller 10, the lowermost document advances downstream by the conveying force received from the feeding roller 10.
In FIG. 3, the broken line indicated by the symbol E indicates the conveyance locus of the conveyed document.

  In the present embodiment, the feeding roller 10 and the separation roller 11 are provided in the central region of the document in the document width direction (X direction) although not shown. In the present embodiment, the reference position in the document width direction (X direction) is the center, and the document fed in the above manner has a central portion in the document width direction at the center in the document width direction regardless of its size. 11 is contacted.

  Subsequently, on the downstream side of the feeding roller 10 and the separation roller 11, a document conveying unit including feeding rollers 12 and 13 is provided. The lowermost document sent out by the feeding roller 10 receives a feeding force from the feeding rollers 12 and 13 and is further conveyed downstream.

  On the downstream side of the feed rollers 12 and 13, reading sensors 16 and 17 as document reading means are vertically opposed to each other. In the present embodiment, the reading sensors 16 and 17 are configured as a contact image sensor module (CISM) as an example.

  After the document is read by at least one of the front surface and the back surface by the reading sensors 16 and 17, the document discharge port is provided by a document discharge means including feed rollers 14 and 15 positioned downstream in the transport direction of each sensor. 8 is discharged.

The above is the general configuration of the image reading apparatus 1, and the configuration of the document feeder 3 will be described in detail below with reference to FIG. Hereinafter, various lines shown in FIG. 4 will be described first.
The straight line L1 is a straight line connecting the axis center C1 of the rotation shaft 10a of the feeding roller 10 and the axis center C2 of the rotation shaft 11a of the separation roller 11.
A straight line M1 is an entry path (entrance) to the feeding roller 10 at the center in the width direction (X direction) of the lowermost document to be fed (portion entering between the feeding roller 10 and the separation roller 11). Angle). The straight line M <b> 1 is also a tangent line that contacts the outer periphery of the feeding roller 10.
A straight line M2 indicates a passage route of a portion other than the central portion in the width direction (X direction) of the lowest document to be fed (details will be described later).
A straight line M3 indicates a rush path (one example) of the document to be prevented from being double fed to the separation roller 11.
The straight line L2 is a line orthogonal to the straight line M1 at a position where the straight line M1 is in contact with the feeding roller 10.

  Reference numerals 20 and 21 are guide members provided on both sides in the X direction with respect to the feeding roller 10 and the separation roller 11. The guide members 20 and 21 guide the width direction (X direction) central portion of the lowest document to be fed between the feeding roller 10 and the separation roller 11, and from between both rollers. Guided downstream. Accordingly, the straight line M1 varies depending on the shape of the guide members 20 and 21 and the protruding amount.

Since the lowermost document to be fed is guided by a guide member (not shown) located at a position lower than the guide members 20 and 21 except for the central portion (for example, both end portions) in the width direction (X direction). A route such as a straight line M2 shown as an example is traced. Accordingly, the straight line M2 also changes depending on the shape of the guide members 20 and 21 and the protruding amount.
Further, in FIG. 4, a symbol α indicates an angle formed by the straight line L1 and the straight line L2.

As the angle α is increased, the straight line M3 enters the separation roller 11 at a steep angle. Therefore, as the angle α is increased, the double feed suppression effect is increased.
Further, as the angle α is increased, the straight line M1 also enters the separation roller 11 at a steep angle. Therefore, as the angle α is increased, the lowermost document to be fed enters the separation roller 11 at a steep angle, so that non-feeding is likely to occur.
Further, as the angle α is increased, the lowermost document to be fed is pressed against the feeding roller 10 at the rear end side.
If the angle α is reduced, the reverse phenomenon will occur. For example, the angle α can be set in a range of less than 20 degrees.

By the way, there are various types of originals such as thick paper and thin paper, that is, those that are easy to separate depending on the types of the original and those that are difficult to separate. Also, depending on environmental conditions such as humidity, there are conditions that are easy to separate and conditions that are difficult to separate. On the other hand, the separation performance when the original is separated by the separation roller 11 and the feeding roller 10 can be adjusted by changing the angle α as described above.
The document feeder 3 according to the present embodiment is configured to be able to adjust the angle α. Hereinafter, this adjustment mechanism will be described with reference to FIG.

  In FIG. 5, reference numeral 27 denotes a gear provided at both ends of the rotation shaft 10 a of the feeding roller 10. The rotary shaft 10a is formed longer than the assumed maximum document width, and the gears 27 are provided at both ends of the rotary shaft 10a. However, the gear 27 is provided so as to be rotatable relative to the rotary shaft 10a.

Reference numeral 26 denotes a support arm provided integrally with the gear 27, and the support arm 26 supports the rotating shaft 11 a of the separation roller 11. However, the rotating shaft 11a is supported by the support arm 26 so as to be freely rotatable. The rotating shaft 10a is also freely rotatable with respect to the support arm 26.
With the above configuration, when the support arm 26 swings around the rotation shaft 10a, the separation roller 11 moves in a planetary motion around the feeding roller 10.

  On the other hand, the gear 27 meshes with the gear 27. Reference numeral 28 is provided at both ends of a rotating shaft 28a extending in the document width direction. A motor 30 is disposed on one side of the two gears 28, and the motor 30 transmits power to the gear 28 via the pinion gear 29. That is, the separation roller 11 is displaced around the feeding roller 10 by the driving force of the motor 30.

The motor 30 is controlled by the control unit 31. The control unit 31 is also a control unit that controls document conveyance and image reading operations in the image reading apparatus 1.
Information from the user input unit 32 that receives an operation input from the user is input to the control unit 31. Examples of the user input unit 32 include an input device (a keyboard, a mouse, etc.) of a terminal such as a computer connected to the image reading apparatus 1.
Information from the height detection means 18 is input to the control unit 31. The height detection means 18 is provided in the vicinity of the upstream side of the feeding roller 10 as shown in FIG. 3, and is a detection means for detecting the stacked height of the set originals G. The height detecting means 18 can be constituted by a known ultrasonic sensor, for example.

Information from the document detection means 19 is input to the control unit 31. As shown in FIG. 3, the document detection means 19 is provided in the vicinity of the downstream side of the feeding roller 10, detects whether the leading edge or the trailing edge of the document has passed, and feeds only one document. Or detecting means for detecting whether the paper is being double-fed. That is, the document detection unit 19 serves as both a non-feed detection unit that detects a non-feed of a document and a double feed detection unit that detects a multi-feed of documents. The document detection means 19 can be constituted by a known ultrasonic sensor, for example.
Further, information from humidity detecting means 33 for detecting humidity is input to the control unit 31. Although not shown in FIG. 3, the humidity detecting means 33 is provided in the vicinity of the height detecting means 18 in this embodiment.

In the present invention, the user input means 32, the height detection means 18, the document detection means 19, and the humidity detection means 33 are arbitrary constituent elements and may not be provided with all of them. One or a combination of the two may be provided.
Furthermore, a detecting means for detecting the posture of the support arm 26 may be provided. With this posture detection means, the current position of the separation roller 11 (and hence the angle α in FIG. 4) can be detected.

  Control performed by the control unit 31 in the document feeder 3 having the above configuration will be described with reference to FIG. When the feeding operation is started (step S101), the control unit 31 determines whether the adjustment flag is “0” (step S102). This adjustment flag indicates whether or not to adjust the position of the separation roller 11. If “0” (Yes in step S102), the process proceeds to step S105. If the adjustment flag is not “0”, that is, “1” or “2” (No in step S102), the motor 30 is controlled to adjust the position of the separation roller 11 (step S103). Thereafter, the adjustment flag is reset to “0” (step S104).

  Next, it is detected whether or not the document detection means 19 has detected a document when the feeding roller 10 is rotated by a predetermined amount (steps S105 and S106). When a document is detected (Yes in step S106), it is detected whether the detected content is only one document or two or more documents, that is, double feed (step S107). If double feeding is not detected (No in step S107), the feeding process is terminated, and the document transport operation and the reading operation are subsequently performed (the description thereof is omitted).

  On the other hand, if the original is not detected in step S106, that is, if it can be determined that the document is not sent (No in step S106), the adjustment flag is set to "1" (step S110). If double feed is detected in step S107 (Yes in step S107), the adjustment flag is set to “2” (step S108). Then, an alert corresponding to non-feed or double feed is issued (step S109). This alert may be displayed on a display of a terminal such as a computer (not shown) connected to the image reading device 1, or a warning lamp (not shown) provided in the image reading device 1 may be turned on or blinked. good.

  The adjustment flag set as described above is used in step S103 after starting document feeding as described above. Hereinafter, the position adjustment of the separation roller 11 performed in step S103 will be further described.

When the adjustment flag is “1”, it indicates that a non-feed has occurred in the previous document feeding. Therefore, in this case, the control unit 31 moves the separation roller 11 in a direction in which the angle α in FIG. 4 decreases. The amount of movement of the separation roller 11 at this time can be set in advance, for example.
By adjusting the position of the separation roller 11 as described above, the entry angle of the leading end of the document with respect to the separation roller 11 is reduced, and non-feeding is suppressed.

On the other hand, when the adjustment flag is “2”, this indicates that double feeding has occurred in the previous document feeding. Therefore, in this case, the control unit 31 moves the separation roller 11 in a direction in which the angle α in FIG. 4 increases. The amount of movement of the separation roller 11 at this time can be set in advance, for example.
By adjusting the position of the separation roller 11 as described above, the entry angle of the leading end of the document with respect to the separation roller 11 is increased, and double feeding is suppressed.

  The characteristics of the image reading apparatus 1 configured as described above are summarized as follows. First, the document feeder 3 provided in the image reading apparatus 1 includes a cover unit 6 as a placement unit on which a document as an example of a medium is placed, a feed roller 10 that feeds a document from the cover unit 6, and a feed. And a separation roller 11 that separates the document by nipping the document with the roller 10. The position where the separation roller 11 is in contact with the feeding roller 10 can be adjusted.

Therefore, it is possible to adjust the separation performance of the document without exchanging apparatus constituent members such as the separation roller 11 or the feeding roller 10. Thereby, it is possible to appropriately separate more types of documents.
In addition, since the optimum and minimum load settings can be made in the separation unit, the durability of the separation roller 11 or the feeding roller 10 is improved, and the frequency of component replacement can be reduced.

Further, in the present embodiment, the separation roller 11 is configured to be able to adjust the position by swinging around the rotation axis center (C1 in FIG. 4) of the feeding roller 10. In FIG. 4, the arc line N indicates the movement locus of the center C2 around the center C1. Therefore, the distance between the separation roller 11 and the feeding roller 10 can be maintained. Thereby, for example, the urging force that urges the separation roller 11 toward the feeding roller 10 can be easily maintained constant.
However, the present invention is not limited to this, and the position where the separation roller 11 contacts the feeding roller 10 may be adjusted by moving the separation roller 11 in an appropriate direction.

The separation roller 11 is configured to be displaceable together with a path forming member (for example, guide members 23 and 24 in FIG. 3) that forms a document feeding path that forms the periphery of the separation roller 11 and that feeds the document. Also good. With this configuration, it is not necessary to secure a space for displacing the separation roller 11 in the path forming member, and the original can be appropriately guided by appropriately configuring the path forming member.
In addition, by displacing the unit including the separation roller 11, for example, when providing a mechanism for applying a rotational torque in the reverse direction to the separation roller 11, the mechanism is complicated by displacing the unit including the mechanism. Can be avoided.

  The document feeder 3 includes a motor 30 that is a drive source for displacing the separation roller 11 and a control unit 31 that serves as a control unit that controls the motor 30. Thereby, the position adjustment of the separation roller 11 can be automatically performed, and usability is improved.

  In the embodiment described above, the position of the separation roller 11 is adjusted according to the result of double feeding and non-feeding at the time of the previous feeding, but the height detection for detecting the stacking height of the set document bundle. The position of the separation roller 11 may be adjusted according to the detection result of the means 18.

  Specifically, when the stacking height of the originals is high (when the number of originals set is large), there is a higher risk of double feeding than when the height is low (when the number of originals set is small). This is because the frictional force generated between the lowest document to be fed and the document on it increases with the weight of the set. Therefore, when the stack height of the set document bundle is high, the control unit 31 moves the separation roller 11 in the direction in which the angle α in FIG. 4 increases. Then, as the stacking height decreases, the separation roller 11 is moved in a direction in which the angle of FIG. 4 decreases. In this way, appropriate separation according to the stacking height of the originals can be performed.

  In addition, the control unit 31 may displace the separation roller 11 in accordance with information regarding the document input by the user. For example, when the original is thick special paper, if the angle α in FIG. 4 is large, there is a high risk of non-feeding. In this case, the angle α in FIG. 4 is adjusted to be small. In this way, by adjusting the position of the separation roller 11 according to the type of document, it is possible to perform appropriate separation according to the type of document. Note that the document type includes not only the paper quality and paper thickness as described above, but also the size.

  Further, the control unit 31 may displace the separation roller 11 according to the detection result of the humidity detection unit 33. Specifically, when the humidity is high and when the humidity is low, sticking between the originals becomes more prominent and double feeding is likely to occur. In this case, the angle α in FIG. 4 is adjusted to increase. . By doing so, it is possible to perform appropriate document separation according to humidity.

  Further, as described with reference to FIG. 6, the control unit 31 displaces the separation roller 11 in accordance with the feeding result at the previous feeding, that is, according to the double feeding or non-feeding of the document. Therefore, the separation performance can be appropriately maintained by displacing the separation roller 11 according to the occurrence state of double feed or non-feed.

  In the embodiment described above, for example, the document placement angle by the cover unit 6 can be adjusted, and the angle of the straight lines M1, M2, and M3 in FIG. Can be finely adjusted.

  Moreover, the structure shown in FIG. 7 can also be employ | adopted as a mechanism to which the separation roller 11 is displaced. The configuration shown in FIG. 7 is an example in which a biasing unit that biases the separation roller 11 toward the feeding roller 10 is incorporated in a mechanism that displaces the separation roller 11. 7, reference numerals 26a and 26b are obtained by dividing the support arm 26 described with reference to FIG. 5. Hereinafter, the reference numeral 26a is referred to as a first support arm, and the reference numeral 26b is referred to as a second support arm.

  Rods 34, 34 are fixed to the first support arm 26a, and the rods 34, 34 are loosely inserted into the long holes 26c, 26c formed in the second support arm 26b. As a result, the second support arm 26b is slidable in a direction to advance and retreat relative to the first support arm 26a. Thus, the first support arm 26a, the second support arm 26b, and the rods 34 and 34 are integrated to form the support arm 26 shown in FIG.

  A tension spring 35 is provided between the first support arm 26a and the second support arm 26b, and the first support arm 26a is biased toward the second support arm 26b by the tension spring 35. . As a result, the separation roller 11 is urged against the feeding roller 10.

  The displacement mechanism of the separation roller 11 described with reference to FIGS. 5 and 7 is provided in the lower unit 4, but it is also preferable to provide all the displacement mechanisms of the separation roller 11 in the upper unit 5. As a result, when the upper unit 5 is opened, the nip between the separation roller 11 and the feeding roller 10 is released, and the original removal operation when the original jam occurs is facilitated.

  In the above embodiment, the example in which the medium conveying apparatus according to the present invention is applied to the image reading apparatus 1 has been described. However, the present invention is not limited thereto, and the recording unit performs recording on a recording medium (for example, printing paper). The present invention can also be applied to a recording apparatus provided with An example of the recording means is an ink jet recording head, and examples of the recording apparatus include a facsimile and a printer. As an example of the configuration of the recording apparatus, for example, an ink jet recording head may be provided instead of the reading sensor 17 of FIG. 3, and a platen for supporting paper may be provided instead of the reading sensor 16 of FIG.

  Further, 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.

DESCRIPTION OF SYMBOLS 1 Image reader, 3 Document feeder, 4 Lower unit, 5 Upper unit, 6 Cover part, 7 Discharge tray, 8 Document discharge port, 9 Torque limiter, 10 Feed roller, 10a Rotating shaft, 11 Separation roller, 11a Rotating shaft, 12-15 Feed roller, 16, 17 Reading sensor, 18 Height detecting means, 19 Document detecting means, 20-23 Guide member, 26 Support arm, 27 Gear, 28 Gear, 28a Rotating shaft, 29 Pinion gear, 30 motor, 31 control unit, 32 user input means, 33 humidity detection means, G, E document

Claims (11)

A medium placement unit for placing a medium;
A feeding roller for feeding out the medium from the medium mounting section;
A separation roller for separating the medium by nipping the medium with the feeding roller,
The separation roller is configured to be capable of adjusting a position in contact with the feeding roller.
A medium feeding device. The medium feeding device according to claim 1, wherein the separation roller is configured to be capable of adjusting the position by swinging around a rotation axis center of the feeding roller.
A medium feeding device. 3. The medium feeding device according to claim 1, wherein the separation roller is configured to be displaceable together with a path forming member that forms a feeding path for feeding a medium, which forms a periphery of the separation roller. ing,
A medium feeding device. In the medium feeding device according to any one of claims 1 to 3, a driving source for displacing the separation roller;
Control means for controlling the drive source,
A medium feeding device. The medium feeding device according to claim 4, further comprising a height detection unit that detects a stacking height of the medium placed on the medium placement unit,
The control means displaces the separation roller according to the detection result of the height detection means;
A medium feeding device. The medium feeding device according to claim 4 or 5, wherein the control unit displaces the separation roller in accordance with information about a medium input by a user.
A medium feeding device. The medium feeding device according to any one of claims 4 to 6, further comprising humidity detection means for detecting humidity,
The control means displaces the separation roller according to the detection result of the humidity detection means.
A medium feeding device. The medium feeding device according to any one of claims 4 to 7, further comprising a double feed detection unit that detects double feeding of the medium on a downstream side of the feeding roller.
The control means displaces the separation roller according to the detection result of the double feed detection means.
A medium feeding device. The medium feeding device according to any one of claims 4 to 8, further comprising a non-feed detection unit that detects non-feed of the medium on the downstream side of the feed roller,
The control means displaces the separation roller according to the detection result of the non-delivery detection means.
A medium feeding device. Reading means for reading the medium;
The medium feeding device according to any one of claims 1 to 9, wherein the medium is fed to the side of the reading unit.
An image reading apparatus comprising: Recording means for recording on a medium;
The medium feeding device according to any one of claims 1 to 9, wherein the medium is fed to the recording means side.
Recording device.

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