Patent Description:
Hereinafter, a scanner that is an example of an image reading apparatus will be taken as an example and described. The scanner is sometimes configured to enable automatic feeding and reading of plural sheets of documents, each being an example of a medium, to be performed by mounting a feeding apparatus (ADF (Auto Document Feeder)) for automatically feeding the plural sheets of documents.

In such a feeding apparatus, an oblique movement of a document sometimes occurs, and thus, heretofore, a means for dealing with the oblique movement of a document has been employed. As an example thereof, in <CIT>, there is disclosed an image inputting apparatus which is configured to dispose a plurality of paper detection sensors in parallel to a reading line in a feeding portion; includes a means that is capable of detecting a paper movement amount even when a roller slippage has occurred; and determines input start and end positions of an image on the basis of the paper movement amount, the states of the sensors, and the positional relations among the sensors.

In such a feeding apparatus, in general, edge guides for guiding the edges of a document are mounted. The oblique movement of a document being fed is restrained by the edge guides, but, for example, in the case where the medium is such thin paper that is significantly nonelastic, when an edge of the document is brought into contact with one of the edge guides, there may occur a case where the document bends at a contact portion and, as a result, the oblique movement is not restrained. Further, such a problem not only occurs in such nonelastic thin paper, but also is likely to occur in other kinds of paper or due to other factors, such as a setting condition of paper.

Further, when the document is continuously fed while such a state remains as it is, as a result, a crease may occur at an edge portion of the document and thereby the document is likely to be damaged.

In the image inputting apparatus disclosed in <CIT>, the oblique movement of the document can be detected, but the relation between the size of the document and the edge guides is not considered, and thus, the above problem cannot be resolved.

Further, in a configuration in which an anterior end detection means for detecting the anterior end of a document is disposed on the upstream side of a reading sensor, and the reading of the document is started in response to the detection of the anterior end of the document by the anterior end detection means, when a degree of the oblique movement of the document is significant, there may occur a case where, because of the oblique movement, at the time when the anterior detection means has detected the anterior end of the document, part of the anterior end of the document has already reached the reading sensor. In this case, as a result, part of the document is lacked in the reading of the document.

<CIT> discloses an apparatus and method for scanning documents such as ID cards and bank checks that includes hinged cover and base assemblies. The base includes motor driven drive rollers for conveying a document along a paper path defined between the cover and base. Two side-by-side scanning regions are provided, one of which is configured to scan flexible documents, the other of which is configured to scan rigid media such ID cards. Sensors detect the position of the document.

An advantage of some aspects of the invention is that an image reading apparatus in which problems due to the oblique movement of a document being fed have been further taken into consideration is provided.

According to an aspect of the invention, there is provided an image reading apparatus as defined in claim <NUM>.

According to this configuration, the image reading apparatus includes the at least one medium detection means configured to detect the medium and disposed on the further downstream side than the at least one edge guide in the medium feeding direction, and further outside in the medium width direction than the at least one edge regulation position for the edge regulation by the at least one edge guide, and thus, the image reading apparatus is capable of directly detecting the medium having been obliquely moved and having protruded to the outside from one of the at least one edge regulation position, for the edge regulation by the at least one edge guide. With this configuration, the oblique movement of the medium, which, when the feeding of the medium is continued, is likely to cause a damage of an edge of the medium or a lack of an image to be read, is detected with certainty, and consequently, the image reading apparatus in which problems due to the oblique movement of the medium being fed have been further taken into consideration is provided. In the above description, "further outside in the medium width direction than the at least one edge regulation position" means "outside a medium passing region in which the medium is fed and passes without being obliquely moved".

Moreover, the feeding of the medium by the feeding means is stopped in response to the detection of the medium by any one of the at least one medium detection means, and thus, the damage of an edge of the medium is eliminated or minimized.

Preferably, the at least one edge guide and the at least one medium detection means are respectively disposed so as to form a pair of edge guides each associated with a corresponding one of both side edges of the medium and a pair of medium detection means each associated with a corresponding one of the both side edges of the medium.

According to this configuration, the at least one edge guide and the at least one medium feeding means are respectively disposed so as to form a pair of edge guides each associated with a corresponding one of both side edges of the medium and a pair of medium detection means each associated with a corresponding one of the both side edges of the medium, and thus, regardless of the direction of the oblique movement of the medium, the detection of the medium having protruded to the outside from one of the at least edge regulation position for the edge regulation by the at least one edge guide is made with certainty.

Preferably, the at least one edge guide is movable in the medium width direction, and the at least one medium detection means is located further outside than the at least one edge regulation position of the at least one edge guide, the at least one edge regulation position being associated with a maximum size of the medium in the medium width direction.

According to this configuration, the at least one edge guide is movable in the medium width direction, and the at least one medium detection means is located further outside than the at least one edge regulation position of the at least one edge guide, the at least one edge regulation position being associated with a maximum size of the medium in the medium width direction, and thus, for the medium whose size is maximum, that is, for the medium for which, when the medium is continuously fed while being obliquely moved, a damage of an edge of the medium is most likely to be caused, the detection of the medium having protruded to the outside from one of the at least one edge regulation position for the edge regulation by the at least one edge guide is made with certainty, and consequently, the damage of the edge of the medium is eliminated or minimized.

Preferably, the at least one edge guide is movable in the medium width direction, and the at least one medium detection means is disposed so as to form a plurality of medium detection means each associated with a corresponding one of a plurality of medium size standards and disposed along a movement direction of the at least one edge guide.

According to this configuration, the at least one edge guide is movable in the medium width direction, and the at least one medium detection means is disposed so as to form a plurality of medium detection means each associated with a corresponding one of a plurality of medium size standards and disposed along a movement direction of the at least one edge guide, and thus, for any medium having a size conforming to one of the plurality of medium size standards, the detection of the medium having protruded to the outside from one of the at least one edge regulation position for the edge regulation by the at least one edge guide is made with certainty.

Preferably, the at least one edge guide is movable in the medium width direction, and each of the at least one medium detection means is disposed so as to be movable together with a corresponding one of the at least one edge guide in the medium width direction.

According to this configuration, the at least one edge guide is movable in the medium width direction, and each of the at least one medium detection means is disposed so as to be movable together with a corresponding one of the at least one edge guide in the medium width direction, and thus, for any medium among media having various sizes, the detection of the medium having protruded to the outside from one of the at least one edge regulation position for the edge regulation by the at least one edge guide is made with certainty.

Preferably, the image reading apparatus further includes at least one feeding guide disposed further outside than the at least one edge regulation position in the medium width direction and each configured to regulate a corresponding one of the at least one medium width direction edge of the medium being fed. Further, preferably, at least one notch is each formed in a corresponding one of the at least one feeding guide, and each of the at least one medium detection means is disposed inside a corresponding one of the at least one notch.

According to this configuration, the image reading apparatus further includes at least one feeding guide disposed further outside than the at least one edge regulation position in the medium width direction and each configured to regulate a corresponding one of the at least one medium width direction edge of the medium being fed. Further, at least one notch is each formed in a corresponding one of the at least one feeding guide, and each of the at least one medium detection means is disposed inside a corresponding one of the at least one notch. Thus, for a medium whose rigidity is relatively high, even though an oblique movement of the medium is about to begin, the oblique movement is regulated by one of the at least one feeding guide, and since each of the at least one medium detection means is disposed inside a corresponding one of the at least one notch, the oblique movement is not detected by the at least one medium detection means, and consequently, the feeding of the medium is appropriately continued.

Further, for a medium whose rigidity is low, when an edge of the medium is brought into contact with one of the at least one feeding guide, the edge of the medium is caused to bend at a contact portion, and the posture of the medium is not changed. As a result, the edge of the medium is inserted into a corresponding one of the at least one notch, and is detected by a corresponding one of the at least one medium detection means. Thus, the detection of the medium having protruded to the outside from a corresponding one of the at least one edge regulation position for the edge regulation by the at least one edge guide is appropriately made.

Preferably, the image reading apparatus further includes at least one separation roller each configured to separate the medium by nipping the medium with a corresponding one of the at least one feeding roller, and the at least one notch is disposed in a place including at least one nip position between the at least one feeding roller and the at least one separation roller.

According to this configuration, the at least one notch, that is, the at least one medium detection means, is disposed near at least one place (that is, at least one nip position between the at least one feeding roller and the at least one separation roller) at which factors of the occurrence of an oblique movement are likely to arise, and thus, the oblique movement is promptly and appropriately detected.

Preferably, each of the at least one medium detection means includes a first facing portion facing a first face of the medium, and a second facing portion facing a second face that is an opposite side face of the first face. Further, preferably, the first facing portion includes a light emitting portion configured to emit detection light toward the medium, and a first light receiving portion configured to receive a reflected light element of the detection light having been emitted from the light emitting portion, and the second facing portion includes a second light receiving portion configured to receive the detection light having been emitted from the light emitting portion.

According to this configuration, the first facing portion is configured to include the light emitting portion configured to emit detection light toward the medium, and the first light receiving portion configured to receive a reflected light element of the detection light having been emitted from the light emitting portion, and the second facing portion is configured to include the second light receiving portion configured to receive the detection light having been emitted from the light emitting portion. That is, the above configuration allows the single light emitting portion to be utilized as a light emitting portion common to the first light receiving portion and the second light receiving portion, and thus, both of the merit of the detection using a reflected-light receiving method and the merit of the detection using a transmitted-light receiving method are brought about, and simultaneously therewith, the cost reduction of the at least one medium detection means is achieved.

Preferably, the at least one medium detection means is located on the further upstream side than the reading means in the medium feeding direction.

Preferably, the image reading apparatus further includes an anterior end detection means configured to detect the passing of the anterior end of the medium and disposed on the further downstream side than the at least one medium detection means in the medium feeding means. Further, preferably, the control means, configured to control the reading means, allows the reading means to start reading of the medium in the case where, before the detection of the anterior end of the medium by the anterior end detection means, the medium is detected by any one of the at least one medium detection means.

According to this configuration, the control means, configured to control the reading means, allows the reading means to start the reading of the medium in the case where, before the detection of the anterior end of the medium by the anterior end detection means, the medium is detected by any one of the at least one medium detection means, and thus, even when such significant skew that, because of an oblique movement of the medium, causes part of the anterior end of the medium to have already reached the reading means at the time when the anterior end detection means detects the anterior end of the medium has occurred, the lack of an image to be read is eliminated or minimized.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, wherein like numbers reference like elements. ----------.

Hereinafter, an embodiment of the invention will be described with reference to the drawings. It should be noted that, in individual practice examples of the embodiment, identical components will be denoted by identical reference signs, and the description of each of such components will be made only in its first practice example, but the description thereof will be omitted in its subsequent one or more practice examples.

<FIG> is an external perspective view of a scanner according to an embodiment of the invention; <FIG> is a side view of the scanner, according to the embodiment of the invention, illustrating a medium feeding path of the scanner; <FIG> is a block diagram of constituent elements constituting the scanner; <FIG> is a diagram schematically illustrating the medium feeding path of the scanner; <FIG> is a diagram schematically illustrating the medium feeding path of the scanner and illustrating a normal feeding state; <FIG> is a diagram schematically illustrating the medium feeding path of the scanner and illustrating a state in which skew of a medium has occurred; and <FIG> is a flowchart of the feeding of the medium in the scanner, according to the embodiment of the invention.

<FIG> is a diagram schematically illustrating the medium feeding path of the scanner and illustrating a state in which part of the medium has reached an image reading section before the medium is detected by a fifth detection sensor; <FIG> is a diagram illustrating a configuration in which a plurality of fourth detection sensors are disposed in an apparatus width direction on the medium feeding path of the scanner; <FIG> is a diagram illustrating a configuration in which the fourth detection sensors are each disposed on the medium feeding path of the scanner so as to be movable together with a corresponding one of edge guides in the apparatus width direction; <FIG> is a diagram schematically illustrating the configuration of each of the fourth detection sensors according to the embodiment of the invention; and <FIG> is a diagram illustrating a state in which a medium (normal paper) has been detected in one of the fourth detection sensors.

<FIG> is a diagram illustrating a state in which a medium having been subjected to black printing has been detected in one of the fourth detection sensors; <FIG> is a diagram illustrating a state in which a transparent medium has been detected in one of the fourth detection sensors; <FIG> is a diagram illustrating a configuration in which wall portions are disposed on the upstream side of the fourth detection sensors in the medium feeding path of the scanner; <FIG> is a diagram illustrating a state in which a medium having high rigidity has been fed in a configuration of the medium feeding path, in which each of the fourth detection sensors is disposed in a corresponding one of notches of feeding guides; and <FIG> is a diagram illustrating a state in which a medium having low rigidity has been fed in the configuration of the medium feeding path, in which each of the fourth detection sensors is disposed in a corresponding one of the notches of the feeding guides.

Further, in an X-Y-Z coordinate system illustrated in each of the figures, an X direction corresponds to the apparatus width direction and a paper width direction; a Y direction corresponds to a paper transport direction in an image reading apparatus; and a Z direction is a direction orthogonal to the Y direction, and indicates a direction approximately orthogonal to the face of paper being transferred. Additionally, in each of the figures, a +Y-direction side is associated with an apparatus front side, and a -Y-direction side is associated with an apparatus rear side.

A basic concept of these practice examples is that, in a scanner <NUM>, which is an example given as the "image reading apparatus", sensors for detecting skew of a medium P are disposed outside the region of a transport path for transporting the medium P, and upon detection of the skew of the medium P by any one of the relevant sensors, predetermined processing in relation to the feeding of the medium P is performed.

Referring to <FIG> and <FIG>, the scanner <NUM> includes a lower unit <NUM>, an upper unit <NUM>, a cover portion <NUM>, and an ejection tray <NUM>. In the present practice example, although not illustrated, the upper unit <NUM> is attached to the lower unit <NUM> so as to be pivotable relative to the lower unit <NUM> about a pivot supporting point on the paper transport direction downstream side of the lower unit <NUM>.

Further, the cover portion <NUM> is attached to an upper portion of the rear side of the lower unit <NUM> so as to be pivotable relative to the lower unit <NUM>. The cover portion <NUM> is capable of being in any one of two states: one being a non-feeding state (not illustrated) in which the cover <NUM> covers both of the upper unit <NUM> and a feeding inlet <NUM>; the other one being a feeding enabled state in which, as shown in <FIG>, the cover portion <NUM> is in a state of having been pivoted at the apparatus rear side and allowing the feeding inlet <NUM> to be in an exposed state. Further, as shown in <FIG>, when the cover portion <NUM> is in the feeding enabled state, the back face of the cover portion <NUM> functions as a medium mounting portion 16a, and this medium mounting portion 16a mounts thereon the medium P.

Further, an ejection outlet <NUM> is disposed on the apparatus front side of the lower unit <NUM>, and the medium P is ejected from this ejection outlet <NUM>. Further, the lower unit <NUM> includes the ejection tray <NUM>, and this ejection tray <NUM> is drawable from the ejection outlet <NUM> toward the apparatus front side. The ejection outlet <NUM> is capable of being in two states: one being a state of being contained in the bottom portion of the lower unit <NUM> (this state being unillustrated); the other one being a state of being drawn out at the apparatus front side (see <FIG>). Further, in the present embodiment, the ejection tray <NUM> is constituted by a plurality of tray members coupled to one another, and the length of its portion drawn from the ejection outlet <NUM> is adjustable in accordance with the length of the medium P to be ejected.

Next, a medium transport path <NUM> in the scanner <NUM> will be described with reference to <FIG>. Further, in <FIG>, for the lower unit <NUM> and the upper unit <NUM>, only the outlines of their housings are represented by virtual lines. Note that, in <FIG>, a thick line represents a guide path for a medium P transported along the medium transport path <NUM> inside the scanner <NUM>.

In the present practice example, the medium P that is set to be fed through the feeding inlet <NUM> is mounted on and supported by a medium mounting portion 16a, that is, the back face of the cover portion <NUM> taking a posture of having been pivoted at the apparatus rear side relative to the lower unit <NUM>. For the feeding inlet <NUM>, plural sheets of media P can be set. Further, a first detection sensor <NUM> is disposed on the medium mounting portion 16a. The first detection sensor <NUM> is constituted as, for example, a contact-type sensor having a lever or the like, or an optical sensor, and transmits a detection signal to a controller <NUM>, described later, upon detection of the medium P having been set on the medium mounting portion 16a. Further, the medium mounting portion 16a is capable of setting thereon the plural sheets of media P.

In the present practice example, a pair of edge guides <NUM> is disposed on the medium mounting portion 16a. The pair of edge guides <NUM> is configured to be movable in a direction in which the edge guides <NUM> become close to/far from each other in the apparatus width direction. Further, when the medium P has been set on the medium mounting portion 16a, in order to hold the side portions of the medium P, the edge guides <NUM> are allowed to move to positions at which each of the edge guides <NUM> is in contact with a corresponding one of the side portions of the medium P in the apparatus width direction. With this operation, the feeding of the medium P is guided by the edge guides <NUM>. Note that, in <FIG>, portions each enclosed by a chain double-dashed line and denoted by a reference sign <NUM>-<NUM> indicate the edge guides <NUM> being in a state of being most distanced from each other in the apparatus width direction, that is, a width direction of the medium P.

A medium P mounted on the most bottom side among the media P having been mounted on the medium mounting portion 16a is fed by feeding rollers <NUM> toward the downstream side in the feeding direction. The feeding rollers <NUM> are driven and rotated by a feeding drive motor <NUM> (see <FIG>). As an example, as shown in <FIG>, two feeding rollers <NUM> are disposed at spaced positions in the apparatus width direction. The outer peripheral surface of each of the feeding rollers <NUM> is formed of a high friction material (for example, elastomer such as rubber).

Here, in <FIG>, a reference sign G represents a bundle of media P having been mounted (set) on the medium mounting portion 16a. Before the feeding of the medium P, the anterior edge of the bundle G of the media P is held by an unillustrated stopper at a feeding waiting position (the position shown in <FIG>) so as to be regulated from being inserted between the feeding rollers <NUM> and separation rollers <NUM>. These separation rollers <NUM> will be described later. Note that the feeding rollers <NUM> and the separation rollers <NUM> constitute a feeding means <NUM>.

Further, as shown <FIG>, at a position facing each of the feeding rollers <NUM>, a corresponding one of the separation rollers <NUM> is disposed. For the separation rollers <NUM> as well, as shown in <FIG>, two separation rollers <NUM> are disposed, and these two separation rollers <NUM> are disposed at positions corresponding to the respective two feeding rollers <NUM> in the apparatus width direction. Each of the separation rollers <NUM> is disposed in a state of being energized relative to a corresponding one of the feeding rollers <NUM> by an unillustrated energizing means. Further, each separation roller <NUM> is driven and rotated by a transport drive motor <NUM> (see <FIG>) in a rotation direction (an anticlockwise direction in <FIG>) opposite to the rotation direction of the corresponding feeding roller <NUM> (this rotation direction being an anticlockwise direction in <FIG>, that is, a direction in which the medium P is fed toward the downstream side). In the present practice example, the outer peripheral surface of each separation roller <NUM> is formed of a high friction material (for example, elastomer such as rubber) just like each feeding roller <NUM>.

Moreover, in the present practice example, each separation roller <NUM> includes a torque limiter <NUM>. Each separation roller <NUM> is configured to receive a drive torque of the transport drive motor <NUM> via the torque limiter <NUM>.

Here, when a rotation torque received from the corresponding feeding roller <NUM> exceeds a limit torque of the torque limiter <NUM>, each separation roller <NUM> is disconnected from a driving system of the transport drive motor <NUM> by the torque limiter <NUM> so as to rotate following the rotation of the corresponding feeding roller <NUM> (in a clockwise direction in <FIG>).

Further, in the case where, after the start of the feeding of the medium P, plural sheets of media P have been inserted between each separation roller <NUM> and the corresponding feeding roller <NUM>, each separation roller <NUM> is brought into a state of not receiving the rotation torque from the corresponding feeding roller <NUM> and thus, the rotation of each separation roller <NUM>, which follows the rotation of the corresponding feeding roller <NUM>, stops. Further, each separation roller <NUM> receives a drive force of the transport drive motor <NUM> via the torque limiter <NUM> and starts to rotate in a rotation direction opposite to that of the corresponding feeding roller <NUM> (i.e., in the anticlockwise direction in <FIG>). With this rotation, one or more upper media P other than the lowermost medium P to be fed (i.e., one or more media P to be prevented from being multi-fed) do not receive any transport force for proceeding toward the downstream side, and thus are caused to return to the upstream side in the transport direction by the rotation of each separation roller <NUM>. With this configuration, the multi-feeding of the media P is prevented. Note that the lowermost medium P to be fed is in direct contact with the corresponding feeding roller <NUM>, and thus, is caused to proceed toward the downstream side by the transport force received from the corresponding feeding roller <NUM>.

Subsequently, in the medium transport path <NUM>, a second detection sensor <NUM> is disposed on the downstream side of the feeding rollers <NUM> and the separation rollers <NUM>. This second detection sensor <NUM> detects the feeding of the medium P. Further, as an example, as shown in <FIG>, the second detection sensor <NUM> is disposed within a transport region W. This transport region W is a region for transporting a medium P having a maximum feedable size in the apparatus width direction of the medium transport path <NUM>. The second detection sensor <NUM> is constituted as, for example, an optical sensor, and includes a light emitting portion 42a and light receiving portion 42b. Further, the light emitting portion 42a and light receiving portion 42b are disposed at a position where the light emitting portion 42a and light receiving portion 42b face each other via the medium transport path <NUM> interposed therebetween. Further, the second detection sensor <NUM> is configured to, when a medium P has been transported on the medium transport path <NUM>, allow the medium P to be detected in such a way as to cause the medium P to block detection light from the light emitting portion 42a. Further, upon detection of the medium P, the second detection sensor <NUM> transmits a detection signal to the controller <NUM>.

Here, the medium transport region W in the apparatus width direction will be described with reference to <FIG>. The medium transport region W is set to the width of a medium P having a maximum feedable size in the scanner <NUM>. Specifically, the medium transport region W is set as a region between guide faces 22a of the pair of edge guides <NUM>-<NUM> being in a state of being most distanced from each other in the apparatus width direction, each of the guide faces 22a serving as the "edge regulation position". Note that, in <FIG>, a chain double-dashed line denoted by a reference sign W1 indicates the position of one of the guide faces 22a that is an edge regulation position of a left-side one of the edge guides <NUM>-<NUM> being in a state of being most distanced from each other in the apparatus width direction; and another chain double-dashed line denoted by a reference sign W2 indicates the position of the other one of the guide faces 22a that is an edge regulation position of a right-side one of the edge guides <NUM>-<NUM> being in a state of being most distanced from each other in the apparatus width direction.

Referring to <FIG> again, in the medium transport path <NUM>, a third detection sensor <NUM> is disposed on the downstream side of the second detection sensor <NUM> in the medium transport path <NUM>. This third detection sensor <NUM> detects the multi-feeding of the media P. Further, as shown in <FIG>, the third detection sensor <NUM> is disposed within the medium transport region W in the apparatus width direction. In the present practice example, the third detection sensor is constituted as an ultrasonic sensor including a speaker portion 44a and a microphone portion 44b. Further, the third detection sensor <NUM> is configured to allow the speaker portion 44a to oscillate and emit ultrasonic waves toward the medium P passing through the medium transport path <NUM>, and allow the microphone portion 44b to detect transmitted waves from the medium P. In the present practice example, the third detection sensor <NUM> is configured to not only detect the multi-feeding of the media P, but also be capable of detecting the kind of paper, such as thick paper.

Further, in the medium transport path <NUM>, fourth detection sensors <NUM> are disposed on the downstream side of the third detection sensor <NUM>. Each of the fourth detection sensors <NUM> serves as each of "the at least one medium detection means". As an example, as shown in <FIG>, the fourth detection sensors <NUM> are disposed outside the medium transport region W. Specifically, at spaced positions in the apparatus width direction, there are disposed two fourth detection sensors <NUM>: one being disposed outside the left-side edge portion W1 in the apparatus width direction of the medium transport region W; the other one being disposed outside the right-side edge portion W2 in the apparatus width direction of the medium transport region W. Each of the fourth detection sensors <NUM> detects a corresponding one of medium width direction edges of the medium P. This medium width direction is a direction intersecting with the medium transport direction. A specific configuration of each of the fourth detection sensors <NUM> will be described later.

Further, in the medium transport path <NUM>, transport roller pairs <NUM> are disposed on the downstream side of the fourth detection sensors <NUM>. Further, as shown in <FIG>, two transport roller pairs <NUM> (transport drive rollers 48a) are disposed at spaced positions in the apparatus width direction. Each of the transport roller pairs <NUM> includes the transport drive roller 48a and a transport driven roller 48b. The transport driven roller 48b is driven by the transport drive roller 48a to rotate relative to the transport drive roller 48a. In the present practice example, the transport drive rollers 48a are driven and rotated by the transport drive motor <NUM>.

Further, in the medium transport path <NUM>, a fifth detection sensor <NUM> is disposed on the downstream side of the transport roller pairs <NUM>. As an example, the fifth detection sensor <NUM> is constituted as a touch sensor having a lever. Here, when the medium P is transported along the medium transport path <NUM>, the lever of the fifth detection sensor <NUM> is pushed by the anterior end of the medium P and is pivoted toward the downstream side in the transport direction (see a chain double-dashed line portion in each of <FIG> and <FIG>). Through this operation, the fifth detection sensor <NUM> detects the medium P. Further, upon detection of the medium P, the fifth detection sensor <NUM> transmits a detection signal to the controller <NUM>.

On the downstream side of the fifth detection sensor <NUM>, an image reading section <NUM> is disposed. This image reading section <NUM> serves as the "reading means". Here, the image reading section <NUM> includes an upper reading unit 52A and a lower reading unit 52B. The upper reading unit 52A is attached to the upper unit <NUM> so as to face the upper face of the medium P being transported along the medium transport path <NUM>. The lower reading unit 52B is attached to the lower unit <NUM> so as to face the lower face of the medium P being transported along the medium transport path <NUM>. In the present practice example, the upper reading unit 52A and the lower reading unit 52B are constituted as a reading unit, and, as an example, these units are constituted as a contact type image sensor (CISM).

After an image on at least one of the obverse side and the adverse side of the medium P has been read in the image reading section <NUM>, the medium P is nipped by an ejection roller pair <NUM> and is ejected from the ejection outlet <NUM>. The ejection roller pair <NUM> is located on the downstream side of the image reading section <NUM>.

Further, in the present practice example, the ejection roller pair <NUM> includes an ejection drive roller 54a and an ejection driven roller 54b. The ejection driven roller 54b is driven by the ejection drive roller 54a to rotate relative to the ejection drive roller 54a. In the present practice example, the ejection drive roller 54a is driven and rotated by the transport drive motor <NUM>. Note that, in the above description, the transport drive roller 48a and the ejection drive roller 54a are configured to be driven and rotated by a common driving source, that is, the transport drive motor <NUM>, but may be configured to be individually driven and rotated by mutually different driving sources.

Further, the controller <NUM> (see <FIG>) is disposed inside the lower unit <NUM>. In the present practice example, the controller <NUM> is constituted as an electric circuit including a plurality of electronic components. The controller <NUM> receives detection signals from the first detection sensor <NUM>, the second detection sensor <NUM>, the third detection sensor <NUM>, any one of the fourth detection sensors <NUM>, and the fifth detection sensor <NUM>, and then controls the upper reading unit 52A, the lower reading unit 52B, the feeding drive motor <NUM>, which drives and rotates the feeding rollers <NUM>, and the transport drive motor <NUM>, which drives and rotates the transport drive rollers 48a and the ejection drive roller 54a.

Further, as an example, the controller <NUM> is configured to control the transport operation and the image reading operation of the medium P in the scanner <NUM>.

Further, the controller <NUM> may control operations needed for the execution of the medium reading operation in the scanner <NUM> in accordance with instructions from the outside (a PC or the like).

Further, in the present practice example, the medium mounting portion 16a, the feeding rollers <NUM>, the edge guides <NUM>, and the fourth detection sensors <NUM> constitute a medium feeding apparatus <NUM>.

Next, the feeding of the medium P in the medium transport path <NUM> will be described with reference to <FIG>. Referring to <FIG>, in step S1, the controller <NUM> receives an image reading job start signal. Further, in step S2, the controller <NUM> starts the feeding of the medium P (see the medium P represented by a full line in <FIG>) by drivingly rotating the feeding rollers <NUM>, the separation rollers <NUM>, and the transport roller pairs <NUM> (the transport rollers 48a). Further, the medium P with its side portions guided by the edge guides <NUM> is fed toward the downstream side of the medium transport path <NUM>. Further, the medium P having been fed to the downstream side is detected by the second detection sensor <NUM> and the third detection sensor <NUM>. Further, in step S3, the controller <NUM> determines whether or not any one of the fourth detection sensors <NUM> has detected the medium P.

In the case where none of the fourth detection sensors <NUM> has detected the medium P, it is determined that, at minimum, such large skew (an oblique movement) of the medium P that causes the medium P to deviate from the medium transport region W is not occurring. Thus, the controller <NUM> continues the image reading job for the medium P. Further, in step S4, an anterior end PF-<NUM> of a medium P-<NUM> having been fed toward the downstream side in the transport direction (see a portion indicated by a chain double-dashed line and denoted by a reference sign P-<NUM> in <FIG>) is brought into contact with the fifth detection sensor <NUM>, and the anterior end PF-<NUM> of the medium P-<NUM> presses the fifth detection sensor <NUM> toward the downstream side in the transport direction. As a result, the lever-shaped fifth detection sensor <NUM> is pivoted toward the downstream side in the transport direction, and detects the anterior end PF-<NUM> of the medium P-<NUM>.

Further, in step S5, upon reception of the detection signal from the fifth detection sensor <NUM>, the controller <NUM> stops the rotation of each of the feeding rollers <NUM> and allows the image reading section <NUM> to start the image reading of the medium P. Here, as shown in <FIG>, the detection of the anterior end of the medium P-<NUM> by the fifth detection sensor <NUM> means that the medium P-<NUM> has been nipped by the transport roller pairs <NUM>. Thus, the medium P-<NUM> is transported toward the image reading section <NUM> by the transport roller pairs <NUM>, and the image reading of the medium P-<NUM> is performed in the image reading section <NUM>.

Further, although not illustrated, when the medium P is further transported toward the downstream side in the transport direction, the controller <NUM> determines, in step S6, whether or not the second detection sensor <NUM> has detected the posterior end of the medium P. In the case where the second detection sensor <NUM> has not yet detected the posterior end of the medium P, the controller <NUM> continues the process of step S6 while allowing the transport roller pairs <NUM> to continue the transport of the medium P. Further, upon detection of the posterior end of the medium P by the second detection sensor <NUM>, the controller <NUM> allows the process flow to proceed to step S7. Note that, in the present practice example, the configuration that, in step S6, allows the process flow to proceed to step S7 upon detection of the posterior end of the medium P by the second detection sensor <NUM> has been employed, but a configuration that allows the process flow to proceed to step S7, for example, upon detection of the posterior end of the medium P by the fifth detection sensor <NUM> may be employed.

Next, in step S7, the controller <NUM> determines whether or not the first detection sensor <NUM> is in a state of detecting a medium P. That is, the first detection sensor <NUM> detects whether or not a following medium P is set on the medium mounting portion 16a. Here, in the case where the following medium P is set on the medium mounting portion 16a, the controller <NUM> allows the process flow to return to step S2 to start the feeding of the following medium P from the medium mounting portion 16a and repeat the processes from step S2 to step S7.

Further, in the case where the following medium P is not set on the medium mounting portion 16a, after the medium P having been subjected to the reading of the image in the image reading section <NUM> has been ejected onto the ejection tray <NUM>, the controller <NUM> stops the rotations of the transport roller pairs <NUM> and the ejection roller pair <NUM>, and then terminates the image reading job. It should be noted that step S3 can be carried out as long as the medium P is being fed or transported.

Next, a process in the case where, in step S3, any one of the fourth detection sensors <NUM> has detected the medium P will be described. Upon detection of the medium P by any one of the fourth detection sensors <NUM>, the controller <NUM> determines that skew of the medium P is occurring, and allows the process flow to proceed to step S9 to perform first processing. Further, after having performed the first processing, in step S8, the controller <NUM> terminates the image reading job.

Here, referring to <FIG>, for example, there may occur a case where, after having set the medium P on the medium mounting portion 16a, a user forgets the setting of the edge guides <NUM> at positions for guiding the side portions of the medium P, or although a user has set the edge guides <NUM> at the guiding positions, the user carelessly touches any of the edge guides <NUM> and thereby the edge guides <NUM> are caused to move from the guiding positions for guiding the medium P. Further, there may occur a case where, in the apparatus width direction, the distance between the pair of edge guides <NUM>, for guiding the side portions of the medium P, becomes larger than a width PW of the medium P, and as a result, the guide faces 22a are incapable of guiding the side faces of the medium P. Specifically, the above case is a case where, in the apparatus width direction, a distance W3 between the guide faces 22a of the edge guides <NUM> is larger the width PW of the medium P.

Further, when the medium P having been set between the edge guides <NUM> is transferred, there may occur a case where one of the side portions of the medium P is pressed to a corresponding one of the guide faces 22a of the edge guides <NUM> due to the bias between the transport forces of the feeding rollers <NUM> and/or the bias between the transport forces of the separation rollers <NUM>. Here, since, in the case where the thickness of the medium P being transported is thin, the rigidity of the medium P is low, there may occur a case where the relevant side portion of the medium P yields to a force pressed by the corresponding guide face 22a, and as a result, the relevant side portion of the medium P is released or bends toward the upper side of the corresponding guide face 22a. In this case, the edge guides <NUM> become incapable of regulating the movement of the medium P in the apparatus width direction.

As a result, when the medium P has been fed to the downstream side in the medium transport path <NUM> by the feeding rollers <NUM>, there may occur a case where the medium P moves obliquely relative to the path, that is, the medium P is in a skew state (in an oblique movement state) (i.e., the state of the medium P, shown in <FIG>). Further, when the medium P has been in the skew state, part of the medium P protrudes to the outside of the medium transport region W in the apparatus direction. As a result, the part of the medium P passes on one of the fourth detection sensors <NUM> that is disposed outside the medium transport region W, and the relevant fourth detection sensor <NUM> detects the medium P. Further, when any one of the fourth detection sensors <NUM> has detected the medium P before the detection of the anterior end PF of the medium P by the fifth detection sensor <NUM>, the controller <NUM> determines that skew of the medium P is occurring, and performs the first processing. Here, this first processing will be described below.

In the present practice example, as an example, the first processing is processing for stopping the image reading job. More specifically, at the time when any one of the fourth detection sensors <NUM> has detected the medium P, as the first processing, the controller <NUM> stops the rotation drive of each of the feeding rollers <NUM> and the transport roller pairs <NUM> to stop the transport of the medium P. Here, in the case where the transport of the medium P is continued while the skew is remained as it is, a case where, in the image reading in the image reading section <NUM>, part of the medium P protrudes from the image reading region between the upper reading unit 52A and the lower reading unit 52B, and as a result, part of an image to be read is lacked; a case where the medium P is brought into contact with one of the side walls of the medium transport path <NUM> and the damage or crease of the medium P occurs; or a case where, in the worst case, a paper jam occurs inside the medium transport path <NUM> may occur.

Consequently, the above configuration that causes the transport of the medium P to stop reduces the occurrence of the lack of part of a to-be-read image on the medium P, the damage of the medium P, the paper jam inside the medium transport path <NUM>, and or/the like. That is, such failure occurrences can be dealt with without error because any one of the fourth detection sensors <NUM> directly detects that the medium P has been deviated from the medium transport region W due to the skew.

Further, the controller <NUM> issues an error signal by, for example, displaying error information on a display (a display means or the like) of an externally connected PC or the like. As a result, a user is able to, based on the error information, pivot the upper unit <NUM> relative to the lower unit <NUM>, and then, remove, from the medium transport path <NUM>, the medium P for which the skew has occurred. Thereafter, the user is able to perform the reading operation for the relevant medium P by setting the relevant medium P again on the medium mounting portion 16a, and setting the edge guides <NUM> to the positions for guiding the side portions of the medium P.

Next, other practice examples of the first processing will be described with reference to <FIG>. As shown in <FIG>, the degree of skew of a medium P1 (the angle of skew of a medium P1) depends on the width size of the medium P1, the length size of the medium P1 in the transport direction, the degree of the opening of each of the edge guides <NUM> relative to the medium P1 in the apparatus width direction, and/or the like. Further, when the degree of the skew of the medium P1 becomes large, there may occur a case where, in a state in which part of the medium P is detected by any one of the fourth detection sensors <NUM>, part of the anterior end PF of the medium P1 is in a state of having reached the image reading section <NUM> although the fifth detection sensor <NUM> has not yet detected the anterior end PF of the medium P1. In such a state, even though the image reading is started upon detection of the anterior end PF of the medium P1 by the fifth detection sensor <NUM>, part of data related to a to-be-read image on the medium P1 is lacked because the timing of the start of the image reading is delayed from the timing when the part of the medium P1 has reached the image reading section <NUM>.

Thus, in another practice example of the first processing, upon detection of the medium P by any one of the fourth detection sensors <NUM>, the controller <NUM> may perform control so as to start the reading of the medium P in the image reading section <NUM> even though the fifth detection sensor <NUM> has not yet detected the anterior end PF of the medium P. With this configuration, the problem in that the timing of the start of the image reading is delayed from the timing when part of the medium P1 has reached the image reading section <NUM> can be expected to be prevented from occurring, and thus, the problem in that part of data related to a to-be-read image on the medium P1 is lacked can be expected to be prevented from occurring.

Further, as further another practice example, after the detection of the medium P by any one of the fourth detection sensors <NUM>, the controller <NUM> may perform control so as to correct the skew of the medium P. Specifically, as an example, the medium feeding speed may be corrected so as to reduce the skew for the medium P by changing the speeds of the drives of the two feeding rollers <NUM>, disposed at spaced positions in the apparatus width direction, to mutually different speeds. Note that, in the present practice example, instead of the above configuration in which the two feeding rollers <NUM> are driven and rotated by the same feeing drive motor <NUM>, a configuration that allows each of the two feeding rollers <NUM> to be driven and rotated by a corresponding one of mutually different feeding drive motors is applicable.

Further, as another example of the correction of the skew, the parallel degrees of the separation rollers <NUM> relative to the feeding rollers <NUM> may be changed. Specifically, a configuration that allows each of the separation rollers <NUM> to be inclined relative to a corresponding one of the feeding rollers <NUM> by allowing the each separation roller <NUM> to be pivoted or slid in the right direction or the left direction in the apparatus width direction, or a configuration that allows the two separation rollers <NUM> to be coupled to each other through a shaft member, and allows the shaft member to be pivoted or slid, together with the separation rollers <NUM>, toward the downstream side or the upstream side in the transport direction about a supporting point on a left-side portion or a right-side portion of the shaft member in the apparatus width direction may be employed. With these configurations, the parallel degrees of the separation rollers <NUM> relative to the feeding rollers <NUM> are changed, and thus, the medium P can be caused to rotate around the Z axis, thereby enabling the skew of the medium P to be reduced.

Additionally, a pair of wall portions <NUM> may be further disposed on the downstream side of the fourth detection sensors <NUM>. In this case, notches (which expression includes gaps) each containing therein a corresponding one of the fourth detection sensors <NUM> and allowing a medium to be inserted thereinto toward the corresponding fourth detection sensor <NUM> are formed between the wall portions <NUM> on the upstream side and the wall portions on the downstream side. These notches correspond to notches <NUM>, which will be described below with reference to <FIG> and <FIG>.

(<NUM>) Further, a configuration such as shown in <FIG> and <FIG> may be employed. Referring to <FIG> and <FIG>, in the apparatus width direction, a pair of feeding guides <NUM> is disposed outside the guide faces 22a of the pair of edge guides <NUM>. The pair of feeding guides <NUM> constitutes side walls of the medium transport path <NUM>. The feeding guides <NUM> extend along the transport direction of the medium P. Further, in each of the feeding guides <NUM>, a corresponding one of the notches <NUM> is disposed. Each of the notches <NUM> has a concave shape that is concaved from the inside toward the outside in the apparatus width direction.

As an example, the notches <NUM> are disposed at places each including a nip position Y1, and this nip position Y1 corresponds to nip points between the feeding rollers <NUM> and the separation rollers <NUM> in the medium feeding direction (see a chain double-dashed line extending in the right-left direction on the figure in each of <FIG> and <FIG>). Specifically, when, in the medium feeding direction, the beginning position of each of the notches <NUM> is denoted by Y2 and the end position of each notch <NUM> is denoted by Y3, as an example, the beginning position Y2 is located on the further upstream side than the nip position Y1 in the medium feeding direction, and the end position Y3 is located on the further downstream side than the nip position Y1 in the medium feeding direction.

Further, when, in each of the feeding guides <NUM>, a guide face on the further upstream side than the beginning position Y2 in the medium feeding direction is denoted by 60a, and a guide face on the further downstream side than the end position Y3 in the medium feeding direction is denoted by 60b, the upstream-side guide face 60a is located further outside than the downstream-side guide face 60b. Further, in the inside of each of the notches <NUM>, a corresponding one of the fourth detection sensors <NUM> is disposed.

In the above configuration, a case where a medium P4 is fed will be described with reference to <FIG>. This medium P4 has high rigidity. When the medium P4, having high rigidity, is nipped by the feeding rollers <NUM> and the separation rollers <NUM> and is fed toward the downstream side in the feeding direction, there may occur a case where an oblique movement of the medium P4 arises due to the variations of the transport forces with respect to the feeding rollers <NUM> and the separation rollers <NUM>. Note that, in the present practice example, the oblique movement means a state in which, when the medium P4 is transported toward the downstream side in the transport direction, the medium P4 is transported toward the downstream side in the transport direction and further in the medium width direction while being subjected to, not only a transport force that is a transport-direction element, but also a transport force in a direction intersecting with the transport direction, that is, in the medium width direction.

Further, for example, when the medium P4 exits a state of being regulated by the edge guides <NUM>, skew (a rotation) of the medium P4 occurs. Specifically, in <FIG>, for the medium P4, a rotation in the clockwise direction and an oblique movement are occurring. As a result, the right-side portion of the medium P4 in the medium width direction is brought into contact with the upstream-side guide face 60a of one of the feeding guides <NUM>. Here, since the medium P4 has high rigidity, even though the side portion thereof is brought into contact with the upstream-side guide face 60a, a distortion does not occur, or even when a distortion occurs, the distortion is a small distortion, and thus, the skew of the medium P4 is regulated by the upstream-side guide face 60a. With this configuration, at each of the nip points of the feeding rollers <NUM> and the separation rollers <NUM>, slippages occur between the medium P4 and a corresponding one of the feeding rollers <NUM> and between the medium P4 and a corresponding one of the separation rollers <NUM>. As a result, the oblique movement of the medium P4 is corrected (see a chain double-dashed line portion denoted by a reference sign P4-<NUM>), and the medium P4 is not inserted into any of the notches <NUM>. Thus, none of the fourth detection sensors <NUM> detects the side portions of the medium P4. With this configuration, the feeding of the medium P4, having high rigidity, toward the downstream side in the transport direction can be continued.

Next, a case where a medium having low rigidity, that is, a medium P5, is fed will be described with reference to <FIG>. When the medium P5, having low rigidity, has been fed toward the downstream side in the feeding direction and has exited a state of being regulated by the edge guides <NUM> while being nipped by the feeding rollers <NUM> and the separation rollers <NUM>, in the case where skew of the medium P (a rotation in the clockwise direction in <FIG>) occurs, the right-side portion of the medium P5 in the medium width direction is brought into contact with the upstream-side guide face 60a of one of the feeding guides <NUM>. Here, since the medium P5 has low rigidity, when the side portion of the medium P5 has been brought into contact with the upstream side face 60a, the side portion of the medium P5 is caused to bend or crush at a contact portion of the medium P5. As a result, the medium P5 with its posture uncorrected is fed toward the downstream side as it is, and a side portion of the medium P5 is inserted into one of the notches <NUM> (see a chain double-dashed line portion denoted by a reference sign P5-<NUM>). With this configuration, a corresponding fourth detection sensor <NUM> detects the side portion of the medium P5. Through this detection, the medium P having protruded to the outside from the guide face 22a of a corresponding edge guide <NUM> is appropriately detected.

Further, in the medium feeding direction, the notches <NUM> are disposed at positions corresponding to the nip position Y1, that is, positions corresponding to a place where factors of the occurrence of the oblique movement are likely to arise, and thus, the oblique movement of the medium P is promptly and appropriately detected.

Note that, in the above modification example, the configuration that allows the upstream-side guide face 60a to be located further outside than the downstream-side guide face 60b has been employed, but instead of this configuration, a configuration that allows the upstream-side guide face 60a to be located further inside than or in line with the downstream-side guide face 60b may be employed.

Further, in the above modification example, in the medium transport direction, the positions of the notches <NUM> in the feeding guides <NUM> have been disposed at positions corresponding to the nip point position Y1, but instead of this configuration, the notches <NUM> may be disposed at positions further upstream than the nip point position Y1 in the medium transport direction or may be disposed at positions further downstream than the nip point position Y1 in the medium transport direction.

Next, a preferred configuration of each of the fourth detection sensors <NUM> will be described with reference to <FIG>. Referring to <FIG>, each of the fourth detection sensors <NUM> includes a first facing portion 46a and a second facing portion 46b. The first facing portion 46a is disposed on the side of the lower unit <NUM>, that is, on the side facing a first face of the medium P. The second facing portion 46b is disposed on the side of the upper unit <NUM>, that is, on the side facing a second face of the medium P.

The first facing portion 46a includes a light emitting portion 46c and a first light receiving portion 46d. The light emitting portion 46c emits detection light to the medium P. The first light receiving portion 46d receives a reflected light element of the detection light having been emitted from the light emitting portion 46c. Further, the second facing portion 46b includes a second light receiving portion 46e, and this second light receiving portion 46e receives the detection light having been emitted from the light emitting portion 46c. That is, the light emitting portion 46c and the first light receiving portion 46d constitute a reflection sensor, and the light emitting portion 46c and the second light receiving portion 46e constitute a transparent sensor.

<FIG> illustrates a state in which the medium P is not transported at a position where the relevant fourth detection sensor <NUM> is disposed on the medium transport path <NUM>. In this state, the detection light having been emitted from the light emitting portion 46c (see an arrow in <FIG>) is received by the second light receiving portion 46e located on the light axis of the detection light. Thus, the medium P is not detected by the second light receiving portion 46e. Further, the detection light having been emitted from the light emitting portion 46c is not reflected because the medium P does not exist, and thus, reflected light is not received by the first light receiving portion 46d. Thus, the medium P is not detected by the first receiving portion 46d as well. Accordingly, since the medium P is not detected by both of the first receiving portion 46d and the second receiving portion 46e, the controller <NUM> does not receive the detection signal from the relevant fourth detection sensor <NUM>, and thus determines that the relevant fourth detection sensor <NUM> does not detect the medium P.

Next, as shown in <FIG>, when the medium P, as an example, plain paper, has been transported at the position where the relevant fourth detection sensor <NUM> is disposed on the medium transport path <NUM>, the detection light having been emitted from the light emitting portion 46c is blocked by the medium P and thus is not received by the second light receiving portion 46e. As a result, the medium P is detected by the second light receiving portion 46e. On the other hand, the detection light having been emitted from the light emitting portion 46c is reflected by the medium P, and reflected light is detected by the first light receiving portion 46d. As a result, the medium P is also detected by the first receiving portion 46d. Since the medium P is detected by both of the first light receiving portion 46d and the second light receiving portion 46e, the controller <NUM> receives the detection signal from the relevant fourth detection sensor <NUM>, and thus determines that the relevant fourth detection sensor <NUM> has detected the medium P.

Next, as shown in <FIG>, when a medium P2, that is, for example, a medium whose first face side is subjected to black printing, has been transported at the position where the relevant fourth detection sensor <NUM> is disposed on the medium transport path <NUM>, the detection light having been emitted from the light emitting portion 46c is blocked by the medium P2 and thus is not received by the second light receiving portion 46e. As a result, the medium P2 is detected by the second light receiving portion 46e. On the other hand, the detection light having been emitted from the light emitting portion 46c is not reflected at the surface of the medium P2, which is subjected to black printing, and thus, reflected light is not detected by the first light receiving portion 46d. As a result, the medium P2 is not detected by the first light receiving portion 46d. Here, since the medium P2 is detected by the second light receiving portion 46e, the controller <NUM> determines that the relevant fourth detection sensor <NUM> has detected the medium P2.

Next, as shown in <FIG>, when a medium P3, as an example, a transparent medium (such as an OHP sheet), has been transported at the position where the relevant fourth detection sensor <NUM> is disposed on the medium transport path <NUM>, part of the detection light having been emitted from the light emitting portion 46c is not blocked by the medium P3 but transmits through the medium P3, and thus is received by the second light receiving portion 46e. As a result, the medium P3 is not detected by the second light receiving portion 46e. On the other hand, for the detection light having been emitted from the light emitting portion 46c, part of the detection light is reflected at the surface of the medium P3, and thus, reflected light is detected by the first light receiving portion 46d. As a result, the medium P3 is detected by the first light receiving portion 46d. Here, since the medium P3 is detected by the first light receiving portion 46d, the controller <NUM> determines that the relevant fourth detection sensor <NUM> has detected the medium P3.

Here, when the relevant fourth detection sensor <NUM> is constituted by only the light emitting portion 46c and the first light receiving portion 46d, which is a reflection sensor, the medium P2, which is subjected to black printing, cannot be detected. Further, when the relevant fourth detection sensor <NUM> is constituted by only the light emitting portion 46c and the second light receiving portion 46e, which is a transparent sensor, the medium P3, which is transparent, cannot be detected. In the present practice example, the relevant fourth detection sensor <NUM> includes the light emitting portion 46c, the first light receiving portion 46d, which is a reflection sensor, and the second light receiving portion 46e, which is a transparent sensor, and the second light receiving portion 46e is disposed on the light axis of the detection light emitted from the light emitting portion 46c, and thus, the medium P2, which is subjected to black printing, and the medium P3, which is transparent, can be detected by such a set of sensors.

Further, if a detection sensor having a lever, such as the fifth detection sensor <NUM>, is used, the detection of the medium P2, which is subjected to black printing, and the detection of the medium P3, which is transparent, could be detected, but a paper jam on the transport path could not be detected. On the other hand, a conventional reflection sensor or transparent sensor can detect the paper jam. The relevant fourth detection sensor <NUM> in the present practice example includes both of the configuration of the reflection sensor and the configuration of the transparent sensor, and thus, the paper jam can be detected by the relevant fourth detection sensor <NUM>. Accordingly, the configuration of the relevant fourth detection sensor <NUM> enables characteristics that cannot be detected by each of the reflection sensor, the transparent sensor, and the sensor having a lever to be detected by one sensor, and thus, reduces the number of sensors disposed on the medium transport path <NUM>, thereby enabling the cost reduction to be achieved.

In the present practice example, the configuration in which the fourth detection sensor <NUM> includes the light emitting portion 46c, the first light receiving portion 46d, which is a reflection sensor, and the second light receiving portion 46e, which is a transparent sensor, has been employed, but a configuration in which at least one of the second detection sensor <NUM> and the fifth detection sensor <NUM> includes the light emitting portion 46c, the first light receiving portion 46d, which is a reflection sensor, and the second light receiving portion 46e, which is a transparent sensor, may be employed.

Summarizing the above description, the medium feeding apparatus <NUM> includes the medium mounting portion 16a for mounting the medium P; the feeding means <NUM> for feeding the medium P from the medium mounting portion 16a; the edge guides <NUM> for regulating medium width direction edges of the medium P, that is, apparatus width direction edges of the medium P, mounted on the medium mounting portion 16a, the medium width direction, that is, the apparatus width direction, being a direction intersecting with the medium feeding direction; and the fourth detection sensors <NUM> being for use in detecting the medium P and being disposed on the further downstream side than the edge guides <NUM> in the medium feeding direction and further outside than the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, in the apparatus width direction, that is, the medium width direction.

According to the above configuration, the medium feeding apparatus <NUM> includes the fourth detection sensors <NUM> being for use in detecting the medium P and being disposed on the further downstream side than the edge guides <NUM> in the medium feeding direction and further outside than the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, in the apparatus width direction, that is, the medium width direction, and thus, the medium feeding apparatus <NUM> is capable of directly detecting the medium P having been obliquely moved and having protruded to the outside from one of the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>.

With this configuration, the oblique movement of the medium P, which, when the feeding of the medium P is continued, is likely to cause a damage of an edge of the medium P or a lack of an image to be read, is detected with certainty, and consequently, the medium feeding apparatus <NUM> in which problems due to the oblique movement of the medium P being fed have been further taken into consideration is provided.

The pair of edge guides <NUM> and the pair of fourth detection sensors <NUM> are disposed so as to allow each of the edge guides <NUM> and each of the fourth detection sensors <NUM> to be associated with a corresponding one of both side edges of the medium P. According to this configuration, regardless of the direction of the oblique movement for the medium P, the detection of the medium P having protruded to the outside from one of the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, is made with certainty.

The edge guides <NUM> are movable in the apparatus width direction, that is, the medium width direction, and the fourth detection sensors <NUM> are located further outside than the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM> and which are associated with a maximum size of the medium P in the apparatus width direction, that is, the medium width direction. According to this configuration, for the medium P whose size is maximum, that is, for a medium for which, when the medium is continuously fed while being obliquely moved, a damage of an edge of the medium is most likely to be caused, the detection of the medium P having protruded to the outside from one of the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, is made with certainty, and consequently, the damage of the edge of the medium P is eliminated or minimized.

The edge guides <NUM> are movable in the apparatus width direction, that is, the medium width direction, and along a movement direction of the edge guides <NUM>, the plurality of fourth detection sensors <NUM> are disposed at positions each associated with a corresponding one of a plurality of medium size standards. According to this configuration, for any medium having a size conforming to one of the plurality of medium size standards, the detection of the relevant medium having protruded to the outside from one of the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, is made with certainty.

The edge guides <NUM> are movable in the apparatus width direction, that is, the medium width direction, and each of the fourth detection sensors <NUM> is disposed so as to be movable together with a corresponding one of the edge guides <NUM> in the apparatus width direction, that is, the medium width direction. According to this configuration, for any medium among media having various sizes, the detection of the relevant medium having protruded to the outside from one of the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, is made with certainty.

The feeding guides <NUM> for regulating the medium width direction edges of the medium P being fed are disposed on the further downstream side than the edge guides <NUM> in the medium feeding direction and further outside than the guide faces 22a in the medium width direction; the notches <NUM> are each formed in a corresponding one of the feeding guides <NUM>; and the fourth detection sensors <NUM> are each disposed inside a corresponding one of the notches <NUM>. According to this configuration, for the medium P4 whose rigidity is relatively high, even though an oblique movement of the medium P4 is about to begin, the oblique movement is regulated by one of the feeding guides <NUM>, and since the fourth detection sensors <NUM> are each disposed inside a corresponding one of the notches <NUM>, the oblique movement is not detected by the any of fourth detection sensors <NUM>, and consequently, the feeding of the medium P4 is appropriately continued.

Further, for the medium P5 whose rigidity is low, when an edge of the medium P5 is brought into contact with one of the feeding guides <NUM>, the edge of the medium P5 is caused to bend at a contact portion, and the posture of the medium P is not changed. As a result, the edge of the medium P5 is inserted into a corresponding one of the notches <NUM> and is detected by a corresponding one of the fourth detection sensors <NUM>. Thus, the detection of the medium P5 having protruded to the outside from a corresponding one of the guide faces 22a, which are edge regulation positions for the edge regulation by the edge guides <NUM>, is appropriately made.

The feeding means <NUM> includes the feeding rollers <NUM> for feeding the medium P, and the separation rollers <NUM> each for separating the medium P by nipping the medium P with a corresponding one of the feeding rollers <NUM>, and the notches <NUM> are disposed at places each including the nip position Y1 between the feeding rollers <NUM> and the separation rollers <NUM> in the medium feeding direction. According to this configuration, the notches <NUM>, that is, the fourth detection sensors <NUM>, are disposed near places (each including the nip position Y1 between the feeding rollers <NUM> and the separation rollers <NUM>) at which factors of the occurrence of an oblique movement are likely to arise, and thus, the oblique movement is promptly and appropriately detected.

Each of the fourth detection sensors <NUM> includes the first facing portion 46a facing the first face of the medium P, and the second facing portion 46b facing the second face, that is, the opposite side face of the first face. The first facing portion 46a includes the light emitting portion 46c for emitting detection light toward the medium P, and the first light receiving portion 46d for receiving a reflected light element of the detection light having been emitted from the light emitting portion 46c, and the second facing portion 46b includes the second light receiving portion 46e for receiving the detection light having been emitted from the light emitting portion 46c.

According to the above configuration, the first facing portion 46a is configured to include the light emitting portion 46c for emitting detection light toward the medium P, and the first light receiving portion 46d for receiving a reflected light element of the detection light having been emitted from the light emitting portion 46c, and the second facing portion 46b is configured to include the second light receiving portion 46e for receiving the detection light having been emitted from the light emitting portion 46c. That is, the above configuration allows the single light emitting portion 46c to be utilized as the light emitting portion 46c common to the first light receiving portion 46d and the second light receiving portion 46e, and thus, both of the merit of the detection using a reflected-light receiving method and the merit of the detection using a transmitted-light receiving method are brought about, and simultaneously therewith, the cost reduction of the fourth detection sensors <NUM> is achieved.

The scanner <NUM> includes the image reading section <NUM> for reading the medium P, and the medium feeding apparatus <NUM> for feeding the medium P for the image reading section <NUM>.

The controller <NUM> for controlling the feeding rollers <NUM> performs the first processing in response to the detection of the medium P by one of the fourth detection sensors <NUM>. Further, the first processing is processing for stopping the feeding of the medium P by the feeding rollers <NUM>. According to this configuration, the damage of an edge of the medium P is minimized or eliminated.

The fifth detection sensor <NUM> for detecting the passing of the anterior end PF of the medium P is disposed on the further downstream side than the fourth detection sensors <NUM> and on the further upstream side than the image reading section <NUM> in the medium feeding direction, and in the case where, after the detection of the medium P by one of the fourth detection sensors <NUM>, the anterior end PF of the medium P has reached the image reading section <NUM> without having been detected by the fifth detection sensor <NUM>, the controller <NUM> for controlling the image reading section <NUM> allows the image reading section <NUM> to start the reading of the medium P. According to this configuration, even when such significant skew that, because of an oblique movement of the medium P, causes part of the anterior end PF of the medium P to have already reached the image reading section <NUM> at the time the fifth detection sensor <NUM> detects the anterior end of the medium P has occurred, the lack of an image to be read is eliminated or minimized.

Claim 1:
An image reading apparatus (<NUM>) comprising:
a medium mounting portion (16a) configured to mount a medium (P);
feeding means (<NUM>) comprising feeding rollers (<NUM>) configured to feed the medium from the medium mounting portion;
at least one edge guide (<NUM>) each configured to regulate a corresponding one of at least one medium width direction edge of the medium having been mounted on the medium mounting portion, the medium width direction being a direction intersecting with a medium feeding direction;
reading means (<NUM>) configured to read the medium and disposed further downstream than the at least one edge guide in the medium feeding direction;
at least one medium detection means (<NUM>) configured to detect the medium and disposed further downstream than the at least one edge guide in the medium feeding direction and further outside in the medium width direction than at least one edge regulation position (22a) for the edge regulation by the at least one edge guide; and
control means (<NUM>) configured to control the feeding means, characterised in that the control means is configured to determine skew of the medium in response to a detection of the medium by one of the at least one medium detection means, to control the feeding means to continue feeding of the medium when the control means does not determine skew of the medium and to stop feeding of the medium when the control means determines skew of the medium, and to correct a medium feeding speed so as to reduce the skew of the medium by changing the speeds of the feeding rollers.