JP7126375B2 - Image reader - Google Patents

Description

The present invention relates to image reading technology.

In conventional image reading apparatuses, for example, a feeding unit that feeds a sheet and a plurality of medium detection units that detect the sheet detect unevenness in the conveying speed from the amount of skew of the sheet being conveyed. A feeding device is known that detects and determines whether or not a feeding abnormality has occurred based on the detection result (Patent Document 1).

JP 2016-169104 A

In the feeding device of Patent Document 1, an optical sensor that optically detects a sheet is used. However, in the case of an image reading device having an image reading unit, the sensor interferes with the light irradiated onto the sheet for reading the image. There is a possibility that the sheet cannot be detected accurately, or unnecessary light may be reflected in the image read by the image reading unit.

The present invention provides a technique for more reliably detecting abnormal sheet conveyance.

The present invention has a first light source for irradiating a document conveyed on a conveying path with light , captures an image of the document by reflected light from the document, and measures the amount of movement of the document based on the image. a detection unit that detects the direction of movement ;
a reading unit that has a second light source that irradiates light onto a document transported on the transport path, and that reads the document based on reflected light from the document;
The reading unit is located on the same side of the transport path as the detection unit and on a different side of the transport path from the detection unit at a position shifted downstream from the detection unit in the document transport direction. is provided in
The reading unit on a side different from the detection unit with respect to the transport path is provided closer to the detection unit in the transport direction than the reading unit on the same side as the detection unit with respect to the transport path. It is characterized by

According to the configuration of the present invention, it is possible to more reliably detect abnormal sheet conveyance.

FIG. 2 is a cross-sectional view of the document feeding device in a conveying state; FIG. 2 is a cross-sectional view of the document feeding device in a standby state; 3 is a block diagram showing a configuration example of a control section 80 of the document feeding apparatus A; FIG. 6 is a flowchart of processing performed by the document feeder A (control unit 80) that receives an instruction to read the document S stacked on the table 1 from an external device. 4 is a diagram showing a configuration example of a movement detection sensor 45; FIG. FIG. 4 is a diagram showing a configuration example of an image reading unit 70; 4 is a diagram showing the internal configuration of an image reading unit 70 and the positional relationship between the image reading unit 70 and a movement detection sensor 45; FIG. FIG. 5 is a cross-sectional view of a document feeding device according to a second embodiment; 4 is a diagram showing the internal configuration of an image reading unit 70 and the positional relationship between the image reading unit 70 and a movement detection sensor 45; FIG. FIG. 10 is a cross-sectional view of a document feeding device according to a third embodiment; 4 is a diagram showing the internal configuration of an image reading unit 70 and the positional relationship between the image reading unit 70 and a movement detection sensor 45; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the embodiment described below is an example of a specific implementation of the present invention, and is one of the specific embodiments of the configuration described in the claims.

[First Embodiment]
In this embodiment, a document feeding device to which an image reading device is applied will be described. First, a configuration example of the document feeding device according to the present embodiment will be described with reference to FIG. 1 showing a cross-sectional view of the document feeding device.

As shown in FIG. 1, the document feeder A according to the present embodiment feeds one or more documents S stacked on a table 1 (stacking section) provided at the upper end of the rear side of the apparatus main body A1. The originals S are conveyed to a path RT inclined with respect to the horizontal plane (installation surface of the apparatus main body A1) one by one, and read. It is a device for discharging. The document S to be read is, for example, a sheet such as OA paper, a check, a check, a business card, a card, etc., and may be a thick sheet or a thin sheet. Cards are, for example, health insurance cards, driver's licenses, credit cards, and the like.

<Feeding unit>
As shown in FIG. 1, the apparatus main body A1 is provided with a first conveying section 10 as a feeding mechanism for feeding the document S along the route RT of the apparatus main body A1. In this embodiment, the first transport unit 10 includes a feed roller 110 and a separation roller 12 arranged opposite to the feed roller 110 . S is sequentially conveyed one by one in the feeding direction D1.

1 shows the configuration of the document feeder A in the conveying state, and FIG. 2 shows the configuration of the document feeder A in the standby state. In the present embodiment, the feeding direction D1 is inclined at a specified angle with respect to the placement surface of the document feeding device A, and the document S placed on the placement table 1 is fed by its own weight. A document S is supplied to the feeding mechanism.

A roller mounting portion, which is a recessed portion for mounting the feeding roller 110 so as to contact the document S on the mounting surface side of the mounting table 1, is provided on the upper end side of the apparatus main body A1. In this embodiment, a cover member that covers the periphery of the feeding roller 110 mounted inside the roller mounting portion is provided at the end portion of the roller mounting portion so as to be openable and closable. When the cover member is opened, the feeding roller 110 can be attached to and detached from the roller mounting portion.

The feeding roller 110 has two feeding roller portions (a first roller portion and a second roller portion) made of, for example, a rubber material or the like, which are individually attached to wheel portions. 11a, and is individually supported by the feed roller shaft (rotating shaft) 11b. In other words, the one-way clutch 11a of the present embodiment serves as a first one-way clutch portion and a second one-way clutch portion which are provided for a plurality of feeding roller portions separately provided on the left and right sides, respectively.

Further, the feed roller shaft 11b of the feed roller 110 has both shaft ends held by bearings provided in the roller mounting portion, and the cover member and the roller mounting are separated by closing the cover member from above. A bearing structure of the feeding roller shaft 11b is formed between the bearing portion of the roller mounting portion and both ends of the feeding roller shaft 11b are rotatably held between the bearing portion and the cover member in the roller mounting portion. That is, the feeding roller 110 can be easily attached and detached by opening and closing the cover member.

Further, the feed roller shaft 11b of the feed roller 110 is provided with a feed gear portion in the gap in the axial direction of each feed roller portion. This feeding gear portion is gear-connected to a driving gear portion that transmits the driving force of a motor 3 (driving motor) installed in the apparatus main body A1. The feeding gear section has a structure in which the upper portion on the separation roller 12 side is covered by the cover member when the cover member is closed. Accordingly, the cover member can protect the paper dust from adhering to the feeding gear portion.

The feeding gear portion protected by the cover member in this way is provided with a gear diameter smaller than the diameter of each feeding roller portion. Therefore, the driving gear portion partially overlaps each feeding roller portion when viewed in the axial direction of the feeding roller shaft 11b, and the gear connection portion with the feeding gear portion overlaps each feeding roller portion when viewed in the axial direction. is provided as follows. As a result, the outer diameter of the feeding gear portion can be set small, the housing capacity of the feeding roller 110 can be improved, and physical interference with the cover member can be prevented.

The drive gear connected to the feed gear is provided on one end of the drive gear shaft, and the other end of the drive gear shaft is provided with a clutch comprising an electromagnetic clutch or the like. ing. Further, the clutch portion is connected between a drive transmission mechanism (gear train) X to which drive force is transmitted from the motor 3 by a pulley and the drive gear shaft. That is, the driving gear shaft and the drive transmission mechanism X are drivingly connected by the clutch portion of the driving gear shaft. Further, the drive transmission mechanism X for the feeding roller 110 is connected to the drive transmission mechanism for the separation roller 12 . That is, the motor 3 serves as a drive source for the separation roller 12 and the feeding roller 110 .

Here, when the clutch provided on the driving gear shaft is OFF, the reverse driving of the motor 3 (driving for returning the document to the document table 1 side) is not transmitted to the driving gear shaft, and when the clutch is ON. transmits only forward rotation of the motor 3 (driving in the direction of separating and feeding the originals) to the drive gear shaft.

When the clutch portion is turned off, the drive is transmitted only to the separation roller 12 , and the feed roller 110 rotates following the separation roller 12 at this time. As a result, when a multi-feeding detection sensor 40, which will be described later, detects that the documents are multi-fed, the feeding operation is temporarily stopped, and the motor 3 is driven to return the multi-fed documents to the table 1 side. can be done properly. It should be noted that if such a multi-feed retry function is not installed, the clutch section may not be provided.

As described above, in the present embodiment, when the motor 3 is driven and the driving force is transmitted from the driving gear to the feeding gear, the feeding roller shaft 11b moves along with the feeding gear in the feeding direction (FIG. 1). in the direction of the solid arrow D2). At this time, the one-way clutch 11a is engaged with the feed roller shaft 11b, so that the feed roller portion rotates in the feed direction together with the wheel portion.

Here, the conveying speed of the feeding roller 110 is set to be slower than the conveying speed of the conveying roller 21, which will be described later. Therefore, when the fed document S reaches the transport roller 21 and the transport speed of the document S increases, the one-way clutch 11a and the feed roller shaft 11b are disengaged, and the feed roller 110 moves along with the document S. It rotates faster than the speed at which it rotates due to drive transmission from the motor 3.

That is, the document S reaching the transport roller 21 receives a transport force from the transport roller 21 set to have a large speed difference from the feed roller 110 , so that the document S is separated by being pressed against the feed roller 110 and the feed roller 110 . It is pulled out from between the roller 12 and the roller 12 .

At this time, in this embodiment, as described above, the one-way clutches 11a are separately provided for the left and right feeding roller portions, so that the document S reaching the conveying roller 21 is fed in a skewed state. Even if the document S is pulled out from between the roller 110 and the separation roller 12, the independent operation of the one-way clutch 11a suppresses the chain of skew feeding of the succeeding document S (hereinafter referred to as "the effect of suppressing the chain of skew feeding").

Here, as described above, in the feed roller 110 of the present embodiment, since the feed gear portions are arranged in the gaps between the feed roller portions in the axial direction of the feed roller shaft 11b, the feed roller 110 The driving force of the motor 3 is stably transmitted to.

That is, the feed roller 110 receives the biasing force from the separation roller 12, and the drive transmission to the feed roller shaft 11b against this bias is performed between the feed roller portions. In the left and right feeding roller portions, the driving force is transmitted in a well-balanced manner at substantially equal positions.

Further, in the feeding roller 110 of the present embodiment, the separation roller 12 is configured to be pressed against the end portion of each roller on the side of the feeding gear portion among the feeding roller portions.

In other words, the separation roller 12 is evenly urged by a spring or the like against each feeding roller portion of the feeding roller 110. The gear connection between the feeding gear portion and the drive gear portion is further stabilized by adopting a configuration in which the rollers are pressed against the ends of the respective rollers. As a result, the power transmission to the feeding roller 110 can be performed more stably, and the state of contact pressure with the separation roller 12 can be maintained in good balance between the right and left sides.

In this embodiment, as described above, the separation roller 12 is pressed against the end of each roller on the side of the feeding gear (the side facing each other) of the feeding rollers. The roller ends on the side opposite to the feeding gear portion may be in contact with the separation roller 12 , or the central portion of each feeding roller portion in the axial direction may be in contact with the separation roller 12 . In any case, it is preferable that the separating rollers 12 are evenly pressed against the respective feeding rollers.

In this way, the feeding roller portion of the present embodiment receives the biasing force of the separation roller 12 and is pressed against the separation roller 12 in a well-balanced manner on the left and right sides. That is, the posture of the feeding roller 110 with respect to the separation roller 12 is stabilized. Therefore, since the left and right nipping forces are evenly applied to the document S, skewing of the document S can be prevented, and various kinds of documents can be stably fed. . Further, even if the preceding document S is skewed, the individual operation of the one-way clutch 11a can be stably executed for the subsequent document S, so that the effect of suppressing the chain of skew can be further enhanced.

Further, in the present embodiment, the feeding gear portion has a cylindrical portion that holds the feeding roller shaft 11b, and this cylindrical portion protrudes and extends to both sides of the feeding roller shaft 11b in the axial direction. there is As a result, the wheels or one-way clutches 11a that hold the feeding rollers contact the end portions (first and second contact portions) of the cylindrical portions, thereby keeping the intervals between the feeding rollers constant. can be kept in However, the cylindrical portion of the feeding gear portion and the wheel portion or the one-way clutch 11a do not always have to be in contact with each other, and the wheel portion is held so as to be slightly axially movable with respect to the feeding roller shaft 11b. It suffices that the wheel portion can come into contact with the one-way clutch 11a when it moves toward the feeding gear portion. In any case, the cylindrical portion of the feeding gear portion can keep the intervals between the feeding roller portions constant.

That is, the feeding gear portion of the present embodiment serves to regulate the intervals between the feeding roller portions. Although the wheel portion and the end portion of each cylindrical portion of the feeding gear portion have been described as being in contact with each other, the same effect can be obtained by contacting the side surface portion of the one-way clutch 11a.

Further, by substantially covering the one-way clutch 11a with the tubular portions of the feeding gear portion as in the present embodiment, there is an effect of preventing paper dust from entering the gap of the one-way clutch 11a. I can expect it.

The feed roller 110 and the separation roller 12, which will be described later, are each a single unit that can be attached to and detached from the apparatus. Therefore, maintenance is easy, and the unit of the feeding roller 110 can be replaced when the roller surface is worn.

<Separation part>
The separation roller 12 arranged to face the feeding roller 110 described above is a roller for separating the documents S one by one, and is pressed against the feeding roller 110 with a constant pressure. In order to ensure this pressure contact state, the separation roller 12 is supported by a separation rocking member 121 as shown in FIG. The separation rocking member 121 is rotatably supported around a shaft portion 121 a and is biased by a compression spring 122 so that the separation roller 12 is pressed against the feeding roller 110 .

As shown in FIG. 1, the separation roller 12 receives a driving force from the motor 3 via a torque limiter 12a, and is rotationally driven in the direction of the solid arrow D3. Since the torque limiter 12a restricts the transmission of the driving force to the separation roller 12, the separating roller 12 rotates in the direction of the feeding roller 110 (in the direction of the dashed arrow D4) when it is in contact with the feeding roller 110. FIG. As a result, when a plurality of originals S are conveyed to the nip portion (pressure contact portion) N between the feeding roller 110 and the separation roller 12, two or more originals S except one are not conveyed downstream. It can be dammed like this.

The portion where the feeding roller 110 and the separating roller 12 are brought into contact with each other and exert a separating action on the document, that is, the portion which separates the document functions at least as a separating and feeding portion. For example, in the case where the feeding roller 110 is composed of two feeding roller portions as in the present embodiment, the separation feeding portion is each formed by the left and right feeding roller portions and the separation roller 12 . The portion (gap) between the nip portions N, that is, between the feeding roller portions is also included, and has the meaning of a separating feeding portion. Therefore, the downstream region in the feeding direction of the separating feeding section includes the region extending downstream from the gap between the feeding rollers.

In this embodiment, the structure using the separation roller 12 has been described, but the structure is not limited to the form of the roller. is used, and the separation member may be of any form.

<Document detection structure of the feeding section>
In order to detect the presence or absence of the document S on the table 1, a document detection sensor 90 is provided upstream of the feeding roller 110 as shown in FIG. The document detection sensor 90 is a lever-type sensor which is provided so as to hang down from above in the vertical direction due to its own weight. As another example, optical sensors such as medium detection sensors 50 and 60, which will be described later, may be used.

Here, in the present embodiment, the document detection sensor 90 is a sensor that detects the presence or absence of the document S on the upstream side (for example, immediately before) in the feeding direction of the nip portion formed by the separation roller 12 and the feeding roller portion. is. For this reason, the document detection sensor 90 is preferably arranged between the left and right feeding roller portions near the nip portion. is provided in a portion facing the feeding gear portion of the .

For example, when setting the outer diameter of the feeding gear portion for transmitting the driving force, it is preferable to prevent physical interference with the document detection sensor 90 (and the cover member). In some cases, it is desirable to bring the document detection position closer to the nip portion in order to increase the .

Therefore, in order to achieve both of these, it is necessary to arrange the feeding roller portion and the feeding roller portion so that the leading end portion of the document detecting sensor 90 overlaps the feeding roller portion and the feeding gear portion in the axial direction of the feeding roller portion. It is preferable that each of them extends like a fang between the gear portions.

Also in this case, it is preferable to interpose a cover member between the document detecting sensor 90 and the feeding gear portion. In this case, the central portion of the cover member protrudes toward the separation roller 12 in order to prevent interference with the feeding gear portion, and both sides of the central portion protrude toward the feeding roller shaft in order to prevent interference with the document detection sensor 90 . It is preferable that the shape protrudes toward the 11b side.

As a result, the cover member covers the periphery of the feed roller 110 including the feed gear portion, thereby preventing paper dust from adhering to the drive system, while preventing the drive portion of the feed roller 110 and the cover member from adhering to the drive system. It is possible to structurally separate the document detecting portion for detecting the presence or absence of the document by the document detecting sensor 90 on the surface.

It is preferable that the tooth-shaped leading end portions of the document detection sensor 90 are connected to each other in order to secure the rigidity of the document detection sensor 90. It is preferable to form it in a shape that bypasses the downstream side in the feeding direction. As a result, it is possible to bring the document detection position closer to the nip portion while ensuring the rigidity of the document detection sensor 90, and to increase the degree of freedom in designing the feeding gear portion.

By adopting the lever-type document detection sensor 90 as in the present embodiment, the space for providing the feeding gear section in the feeding roller 110 is ensured, and in addition to high-precision document detection, even contact pressure on the left and right sides is ensured. Good separation feeding can be performed in the state.

<Pick Arm/Document Stopper>
As shown in FIG. 1, the document feeding apparatus A includes a pick roller 131 that presses the document S against the feeding roller 110 on the upstream side of the nip portion (pressure contact portion) where the feeding roller 110 and the separation roller 12 are in contact, and a pick roller 131 that presses the document S against the feeding roller 110 . A pick arm 13 pivotally supporting 131 is provided. The pick roller 131 presses the document S against the feeding roller 110 to increase the transport force of the document S and assist the feeding of the document S. FIG.

The pick arm 13 has a shaft portion 13 a rotatably supported by the document feeder A, and is biased by a spring (not shown) in a direction to press the pick roller 131 against the feed roller 110 . The pick arm 13 has a pressing position where the pick roller 131 presses the document S against the feed roller 110 shown in FIG. 1 and a retreat position where the pick roller 131 retreats from the feed roller 110 shown in FIG. can be moved by the driving force of the motor 4 of .

As another configuration for assisting the feeding of the feeding roller 110, there is a configuration in which another feeding roller is provided upstream of the feeding roller 110, but the configuration of FIG. down can be achieved.

The document feeder A has a document stopper 14 as shown in FIG. The original document stopper 14 has a role of blocking the stack of original documents by protruding its leading end toward the conveying path (path RT) in the state shown in FIG.

The document stopper 14 has a shaft portion 14a of the document stopper 14 rotatably supported by the document feeder A, and the document stopper 14 has an opening position at which the transport path is opened so that the document S shown in FIG. 1 can be fed, and an opening position shown in FIG. and a closing position for closing the conveying path so that the document bundle does not enter the feeding nip. FIG. 2 shows the standby state of the document feeder A. In this state, the document stack can be set on the platen 1 by abutting the front end of the document stack against the document stopper 14 .

The motor 4 is connected via a pulley P and a belt to one end of the transport roller shaft that holds the transport roller 21 and the transport roller shaft that holds the transport roller 31 .

That is, the motor 4 is a drive source for driving the conveying rollers 21 and 31, and is provided as a motor separate from the motor 3 for driving the feeding rollers. Accordingly, if the motors 3 and 4 are individually controlled, highly accurate feeding and conveying control can be realized by separately controlling the feeding drive and the conveying drive.

The pick arm 13 and document stopper 14 are driven via a drive transmission mechanism Y by the motor 4 that drives the transport rollers 21 and 31 described above. When the motor 4 drives a predetermined number of pulses in the forward direction, the pick arm 13 moves to the pressing position and the document stopper 14 moves to the opening position. moves to the retracted position, and the document stopper 14 moves to the closed position. Here, the forward direction is the direction in which transport rollers 21 and 31 (to be described later) are rotated so as to transport the document S in the feeding direction D1 in FIG.

<Transport structure>
As shown in FIG. 1, the second conveying unit 20 as a conveying mechanism located downstream of the first conveying unit 10 in the feeding direction includes a conveying roller 21 and a driven roller 22 that follows the conveying roller 21. The document S conveyed from the first conveying section 10 is conveyed downstream. A driving force is transmitted from the motor 4 to the conveying roller 21, and the conveying roller 21 is rotationally driven in the direction of the solid line arrow in the drawing. The driven roller 22 is pressed against the conveying roller 21 with a constant pressure and rotates with the conveying roller 21 .

The third conveying unit 30 located on the downstream side in the feeding direction of the second conveying unit 20 includes a conveying roller 31 and a driven roller 32 that follows the conveying roller 31. The received document S is conveyed to the discharge tray 2 . In other words, the third conveying section 30 functions as a discharge mechanism. A driving force is transmitted from the motor 4 to the conveying roller 31, and the conveying roller 31 is rotationally driven in the direction of the solid line arrow in the drawing. The driven roller 32 is pressed against the conveying roller 31 with a constant pressure and is rotated with the conveying roller 31 .

<Double feed detection>
As shown in FIGS. 1 and 2, the multi-feeding detection sensor 40 arranged between the first conveying section 10 and the second conveying section 20 detects that the originals S such as paper are in close contact with each other due to static electricity or the like. This is an example of a detection sensor (a sensor that detects the behavior and state of the originals S) for detecting when the originals S have passed through the conveying unit 10 (that is, in the case of a multi-feed state in which the originals S are conveyed overlapping each other).

Various sensors can be used as the double feed detection sensor 40, but in the case of this embodiment, it is an ultrasonic sensor, which is equipped with an ultrasonic wave transmitting unit 41 and an ultrasonic wave receiving unit 42, and detects a document such as paper. Multi-feeding is detected based on the principle that the amount of attenuation of ultrasonic waves passing through the originals S differs between when the documents S are multi-fed and when the documents S are conveyed one by one.

<Movement detector>
In this embodiment, the behavior of the document is detected by acquiring an image of the document S transported on the transport path using the movement detection sensor 45 and detecting the amount of movement based on the image information. The movement detection sensor 45 is arranged at a predetermined distance from the imaging reference plane in the transport path along which the document S is transported. The imaging reference plane is a plane that faces the movement detection sensor 45 and serves as a reference for imaging by the movement detection sensor 45. In the present embodiment, it is the surface of the transport path along which the document S (sheet) that is the object to be imaged is transported. is defined as the imaging reference plane. By separating the movement detection sensor 45 from the imaging reference plane by a predetermined distance, the image of the document can be acquired at appropriate intervals regardless of the type of the document or the position where the movement detection sensor 45 is arranged. Therefore, as the movement detection sensor 45, it is preferable to use a sensor that can focus on the document at a predetermined distance.

For example, as shown in FIG. 5, the movement detection sensor 45 includes a light source 213 that emits light toward the transport path, and reflected light from the document S (reflected light from the document S with respect to the light emitted from the light source 213). and an image pickup unit 211 for picking up an image of the document S by receiving the light.

The light source 213 is, for example, a light-emitting element (laser light source) that outputs infrared laser light, and the imaging unit 211 is configured by, for example, sensor elements including light-receiving elements. The mold members 212 a and 212 b that block light and the translucent plate (filter) 212 c that transmits light constitute part of a case body 212 that covers the image pickup section 211 and the light source 213 . Mold members 212 a , 212 b form walls perpendicular to substrate 200 . The light-transmitting plate 212c is connected to the ends of the mold members 212a and 212b opposite to the ends on the substrate 200 side. In the arrangement of FIG. 5, the wall formed by mold member 212b is longer than the wall formed by mold member 212a so that transparent plate 212c is inclined with respect to the surface of substrate 200 or the imaging reference plane described above. ing.

The light-transmitting plate 212c transmits light that is output from the light source 213 and directed toward the document S. As shown in FIG. The light transmitted through the transparent plate 212 c and reflected by the document S is transmitted through the transparent plate 212 c and received by the imaging unit 211 . Such a configuration of the movement detection sensor 45 can prevent paper dust from directly adhering to the movement detection sensor 45, and can also prevent paper dust from being erroneously extracted as a feature point. The wavelength of the light emitted from the light source 213 is preferably in the near-infrared region of about 850 nm, and the transparent plate 212c is preferably a filter capable of transmitting light in that band. In addition, in preparation for the case where light is reflected by the light-transmitting plate 212c, a material having a reflectance r2 (r1>r2) lower than the reflectance r1 of the light-transmitting plate 212c may be used for the mold members 212a and 212b. . As a result, it is possible to effectively reduce excess reflected light directed toward the imaging unit 211 after being reflected by the inner walls of the mold members 212a and 212b. This is a countermeasure against erroneous detection of the movement amount of the sheet (original document) caused by the reflected light incident on the movement detection sensor 45 as described above.

The movement detection sensor 45 of the present embodiment is, for example, a sensor that is completed in one package. 211 acquires an image obtained by receiving light at a predetermined sampling period, tracks the movement of characteristic points included in the image, and detects the amount or direction of movement of the document S based on the result. sensor.

That is, the movement detection sensor 45 of the present embodiment is a tracking sensor that tracks the movement and change of the feature points of the document within one detection area, and mainly detects the diagonal movement of the document in the conveying path. row) is used as a sensor to detect

Further, in this embodiment, the one-way clutch 11a is provided in each feeding roller portion to suppress the skew chain, and in addition, the feeding gear portion is provided in the gap between the feeding roller portions to transmit the driving force to the feeding roller 110. , the occurrence of skew can be suppressed. However, for example, when a plurality of documents are bound at one side of the corners of the documents by stapling, the binding part becomes the center of rotation of the documents, causing the skewed feeding of the documents, and the separation feeding operation is continued as it is. Otherwise, the document may be damaged. Therefore, the skew of the bound document can be detected by the movement detection sensor 45, and the driving of the separating and feeding section can be temporarily stopped early based on the detection result.

<Registration sensor>
The medium detection sensor 50 arranged downstream in the feeding direction from the double feeding detection sensor 40 is arranged upstream from the second conveying section 20 and downstream from the first conveying section 10. is an example of a detection sensor (a sensor that detects the behavior and state of the document S). Detect whether the edge has been reached or passed. In this embodiment, as shown in FIGS. 1 and 2, the medium detection sensor 50 is provided in the same downstream region as the double feed detection sensor 40 described above on the side of the second conveying section 20. .

Various sensors can be used as the medium detection sensor 50, but in the case of the present embodiment, an optical sensor is provided, which includes a light emitting portion 51 and a light receiving portion 52 for the light emitting portion 51. The document S is detected based on the principle that (the amount of received light) changes.

In this embodiment, when the leading edge of the document S is detected by the medium detection sensor 50, the document S reaches a position where the multi-feed detection sensor 40 can detect the multi-feed. The sensor 50 is provided in the vicinity of the double feed detection sensor 40 on the downstream side thereof. Note that the medium detection sensor 50 is not limited to the optical sensor described above. For example, a sensor (image sensor or the like) that can detect the edge of the document S may be used, or a lever-type sensor projecting onto the path RT may be used. It's okay.

A medium detection sensor 60 different from the medium detection sensor 50 is arranged upstream of the image reading unit 70 . The medium detection sensor 60 is an example of a downstream detection sensor arranged downstream of the second transport unit 20 and detects the position of the document S transported by the second transport unit 20 .

Various sensors can be used as the medium detection sensor 60, but in the present embodiment, like the medium detection sensor 50, it is an optical sensor including a light emitting unit 61 and a light receiving unit 62. Alternatively, the document S is detected based on the principle that the intensity of received light (amount of received light) changes due to passage.

<Placement of CIS>
The image reading unit 70 located downstream of the medium detection sensor 60, for example, optically scans, converts it into an electrical signal, and reads it as image data. etc. That is, the image reading unit 70 is configured by a contact image sensor (CIS) that reads the document S. As shown in FIG.

The image reading unit 70 will be described with reference to FIG. As shown in FIG. 6, the image reading unit 70 includes an LED 304 as a light source, a light guide 301 for linearly diffusing the light from the LED 304, and an image sensor (to be described later) that receives the reflected light from the document S. and a rod lens array 303 for guiding to the element 305 . Although not shown in FIG. 6, at the back of the rod lens array 303, the light receiving elements of the image sensor and the substrate on which the elements are mounted are installed. The LEDs 304 are composed of red, green, and blue LEDs and are connected to a drive circuit (not shown). Also, the LEDs 304 and the light guide 301 can be replaced with a linear array of LEDs.

FIG. 7 shows the internal configuration (sectional view) of the image reading unit 70 and the positional relationship between the image reading unit 70 and the movement detection sensor 45 . As shown in FIG. 7, the image reading unit 70 is positioned downstream from the movement detection sensor 45 in the direction of the arrow (conveyance direction of the original document S) in the same direction as the movement detection sensor 45 with respect to the path RT (conveyance path). located on the side.

A document 307, which is an example of the document S, is conveyed in the direction of the arrow (conveyance direction) in the path RT. A light receiving element 305 of the image sensor is mounted on a substrate 306 . Here, as shown in FIG. 7, the light guide 301 (light source) is arranged such that the direction of light irradiation is directed downstream in the transport direction so that the light reflected by the document S can easily enter the rod lens array 303 . Since it is tilted, in this embodiment, the light from the movement detection sensor 45 (light source 213) is prevented from interfering with the light from the light guide 301 (the irradiation range of the light from the light source 213 is the light guide 301). In order not to overlap the irradiation range of the light from 301), the movement detection sensor 45 is mounted inside the apparatus main body A1 so that the light source 213 irradiates light perpendicularly to the transport path. As described above, in FIG. 7, the movement detection sensor 45 is mounted inside the apparatus main body A1 so that the light source 213 irradiates light perpendicularly to the transport path, and the light guide 301 irradiates the light downstream in the transport direction. , the light from the light source 213 and the light from the light guide 301 do not interfere with each other. It is possible to solve the problem that unnecessary light may be reflected in the image read by the image reading unit 70 . The movement detection sensor 45 is preferably installed inside the apparatus main body A1 so that the light source 213 emits light toward the upstream side in the feeding direction (upstream side in the transporting direction).

In this embodiment, as shown in FIG. 7, since the movement detection sensor 45 is arranged upstream of the image reading unit 70, the light guide body 301 is placed upstream of the rod lens array 303, and the light is guided. Although the body 301 is tilted so as to irradiate light downstream in the feeding direction, if the arrangement of the image reading unit 70 and the movement detection sensor 45 is reversed, the light guide body 301 will come to the downstream side of the rod lens array 303. , and the light guide 301 may be tilted so as to irradiate the light upstream in the feeding direction. At this time, the movement detection sensor 45 is mounted in the apparatus main body A1 so that the light source 213 irradiates light perpendicularly to the transport path or irradiates the light source 213 toward the downstream side in the feeding direction. You can do it.

Note that the combination of the respective positions of the light source 213 and the light guide 301 and the light irradiation direction so that the light from the light source 213 and the light from the light guide 301 do not interfere with each other is not limited to the above example. That is, one of the light source 213 and the light guide 301 irradiates light to a side different from the side on which the other of the light source 213 and the light guide 301 is positioned in the direction along the route RT (transportation path).

Next, a configuration example of the control section 80 of the document feeder A will be described with reference to the block diagram of FIG.

The CPU 81 executes processing using the computer programs and data stored in the storage unit 82 to control the operation of the document feeding apparatus A as a whole, and to perform various functions described as being performed by the document feeding apparatus A. perform or control a process;

The storage unit 82 is composed of memory devices such as RAM and ROM, and stores computer programs and data for causing the CPU 81 to execute or control each process described as being performed by the document feeder A.

The operation unit 83 is configured by a user interface such as a switch and a touch panel, and can input various instructions to the CPU 81 by a user's operation.

The communication unit 84 is a communication interface for performing data communication with an external device. Assuming a PC (personal computer) as the external device, the communication unit 84 may be, for example, a USB interface or a SCSI interface. In addition to such a wired communication interface, the communication unit 84 may be a wireless communication interface, or may be provided with both wired communication and wireless communication interfaces.

The interface unit 85 is an I/O interface for inputting/outputting data between the actuator 86 and the sensor 87 . Actuator 86 includes motor 3, motor 4, and the like. The sensor 87 includes the double feed detection sensor 40, the movement detection sensor 45, the medium detection sensors 50 and 60, the image reading unit 70, the document detection sensor 90, and the like.

<Reading Operation of Document S by Document Feeding Apparatus A>
Processing performed by the document feeder A (control unit 80) that receives an instruction to read the document S placed on the table 1 from an external device will be described with reference to FIG. 4 showing a flowchart of the processing. When the document feeder A receives an instruction to read the document S from an external device, it starts driving the first transport section 10 , the second transport section 20 , and the third transport section 30 . S is conveyed sheet by sheet starting with the document S positioned at the bottom. The instruction to read the document S is not limited to being input from an external device to the document feeder A, but may be input to the document feeder A by the user pressing the start button included in the operation unit 83. can be

In step S1, the CPU 81 acquires the reading instruction received by the communication section 84 from the external device.

In step S2, the CPU 81 refers to the signal output from the document detection sensor 90 to determine whether the signal indicates that the document S is placed on the document table 1 or not. determine whether the As a result of this determination, if the signal from the document detection sensor 90 indicates that the document S is placed on the placing table 1, the process proceeds to step S4, and the signal from the document detection sensor 90 indicates that the document S is placed. If it indicates that the document S is not placed on the table 1, the process proceeds to step S3.

In step S3, the CPU 81 displays, for example, an image indicating that the document S is not placed on the table 1 on the screen of the touch panel in order to notify the user that the document S is not placed on the table 1. or characters.

On the other hand, in step S4, the CPU 81 drives the motor 4 in the forward direction. At this time, the pick arm 13 is moved to the pressure contact position, and the document stopper 14 is moved to the open position.

In step S5, the CPU 81 drives the motor 3 to rotate the feeding roller 110 in the direction of feeding the document S (forward direction), thereby feeding the document S. As shown in FIG.

In step S6, the CPU 81 detects, based on the signal from the medium detection sensor 50, that the leading edge of the document S fed in step S5 (hereinafter referred to as the fed document S) has passed through the medium detection sensor 50. In S<b>7 , the CPU 81 detects that the leading edge of the fed document S has passed the medium detection sensor 60 based on the signal from the medium detection sensor 60 .

At this time, since the leading edge of the fed document S has passed the medium detection sensor 60, the fed document S has reached the second conveying section 20, so even if the first conveying section 10 is stopped, the feeding of the manuscript S will continue. Since the document S is transported by the second transport unit 20, the CPU 81 stops the motor 3 in step S8.

On the other hand, the image reading of the fed document S by the image reading unit 70 is started after a predetermined time has elapsed from the time when the leading edge of the fed document S reaches the medium detection sensor 60 until it reaches the image reading unit 70 .

In step S<b>9 , the CPU 81 detects that the trailing edge of the fed document S has passed the medium detection sensor 60 based on the signal from the medium detection sensor 60 . After a lapse of a predetermined time from this time, the image reading of the fed document S by the image reading unit 70 ends. Thus, a series of reading operations for one sheet of the fed document S is completed.

In step S10, the CPU 81 refers to the signal output from the document detecting sensor 90 to determine whether the signal indicates that the document S is placed on the table 1 or not. determine whether the As a result of this determination, if the signal from the document detection sensor 90 indicates that the document S is placed on the placing table 1, the process proceeds to step S5, and the signal from the document detection sensor 90 indicates that the document is placed. If it indicates that the document S is not placed on the table 1, the process proceeds to step S11.

At step S11, the CPU 81 causes the motor 4 to stop. At this time, the motor 4 is stopped after a predetermined period of time has elapsed so that the fed document that has passed through the medium detection sensor 60 is discharged by the third conveying section 30 . When the motor 4 does not drive the third conveying unit 30, the motor 4 may be stopped immediately.

In step S12, the CPU 81 drives the motor 4 in the reverse direction by a predetermined number of pulses, and then stops. At this time, the pick arm 13 is moved to the retracted position and the document stopper 14 is moved to the closed position and stopped. This completes the feeding/conveying operation.

By performing the processing according to the flowchart of FIG. Starts reading an image and outputs the read image to the output destination. The CPU 81 may store the read image in the storage unit 82, display the read image on the screen of the touch panel, or transmit the read image to the external device through the communication unit 84. can be In other words, the output destination of the read image is not limited to a specific output destination. Then, the document S (fed document S) whose image has been read is discharged to the discharge tray 2 by the third conveying section 30, and the image reading processing of the document S is completed. Since the medium detection sensor 60 is used as a trigger to perform transport control for feeding the next document S, a predetermined sheet interval is provided at the reading position of the image reading unit 70, thereby stably feeding the document S continuously. can be transported.

In the flow of reading control described above, the movement detection sensor 45 is used to obtain an image of the document S transported on the transport path, the amount of movement is detected based on the image information, and the amount of movement is determined to be abnormal. If the threshold for is exceeded, it is detected that a transport abnormality has occurred.

[Second embodiment]
In each of the following embodiments (including this embodiment), differences from the first embodiment will be explained, and unless otherwise specified, the embodiments are the same as the first embodiment. In this embodiment, as shown in FIG. 8, the image reading unit 70 is provided on a different side of the route RT from the movement detection sensor 45 .

FIG. 9 shows the internal configuration (sectional view) of the image reading unit 70 and the positional relationship between the image reading unit 70 and the movement detection sensor 45. As shown in FIG. As shown in FIG. 9, the image reading unit 70 is provided at a position shifted downstream in the transport direction from the movement detection sensor 45, as in the first embodiment. It differs from the first embodiment in that it is provided on the side different from 45 . In FIG. 9, the movement detection sensor 45 is mounted inside the apparatus main body A1 so that the light source 213 irradiates light perpendicularly to the transport path, and the light guide 301 irradiates light downstream in the transport direction. is tilted to

In such a configuration, the movement detection sensor 45 and the image reading unit 70 respectively pick up images of different sides of the document 307 that has been conveyed. According to the configuration of FIG. 9, the light from the light source 213 and the light from the light guide 301 do not interfere with each other. It is possible to solve the problem that unnecessary light may be reflected in the image read by the reading unit 70 .

Also in the present embodiment, the combination of the direction of irradiation of light from the light source 213 and the direction of irradiation of light from the light guide 301 is such that the light from the light source 213 and the light from the light guide 301 do not interfere with each other. In this embodiment, the image reading unit 70 is provided on a different side of the route RT from the movement detection sensor 45, although this is basically the same as the first embodiment. Since the image reading unit 70 is provided at a position shifted downstream in the transport direction from the movement detection sensor 45, each of the light source 213 and the light guide 301 emits light perpendicularly to the transport path. Even with such a configuration, the light from the light source 213 and the light from the light guide 301 do not interfere with each other. This is the same even if the arrangement of the image reading unit 70 and the movement detection sensor 45 is reversed.

[Third Embodiment]
In this embodiment, as shown in FIG. 10, an image reading unit 70a is provided above and an image reading unit 70b is provided below the path RT. Both the image reading unit 70a and the image reading unit 70b have the same configuration as that of the image reading unit 70. Hereinafter, the reference number for the image reading unit 70a will be denoted by a, and the image reading unit 70b will be referred to as the image reading unit 70b. The reference numbers for the configurations are suffixed with a b. FIG. 11 shows the internal configuration (sectional view) of the image reading units 70a and 70b and the positional relationship between the image reading units 70a and 70b and the movement detection sensor 45. As shown in FIG. As shown in FIG. 11, the image reading units 70a and 70b are provided at positions shifted downstream in the transport direction from the movement detection sensor 45, as in the first embodiment. It differs from the first embodiment in that an image reading unit 70a is provided on the lower side and an image reading unit 70b is provided on the lower side. In FIG. 11, the movement detection sensor 45 is mounted inside the apparatus main body A1 so that the light source 213 emits light perpendicularly to the route RT. The light guide 301a in the image reading unit 70a located on the same side of the path RT as the movement detection sensor 45 is inclined so as to irradiate light downstream in the transport direction. Further, the light guide 301b in the image reading unit 70b located on the different side of the path RT from the movement detection sensor 45 is inclined so as to irradiate the light downstream in the transport direction. Here, it is necessary to adjust the positions and light irradiation angles of the image reading units 70a and 70b so that the light irradiation ranges of the image reading units 70a and 70b do not overlap.

Of the image reading units 70 a and 70 b , the image reading unit 70 b is arranged at a position closer to the movement detection sensor 45 . That is, the image reading unit 70b on the different side of the transport path from the movement detection sensor 45 is arranged closer to the movement detection sensor 45 than the image reading unit 70a on the same side of the transport path as the movement detection sensor 45 is. At least one of the light guide 301a and the light source 213 of the image reading unit 70a is positioned so that the other of the light guide 301a and the light source 213 of the image reading unit 70a is positioned in the direction along the route RT (conveyance path). irradiate the light on the side different from the side.

In such a configuration, both sides of the document 307 conveyed are imaged by the image reading unit 70a and the image reading unit 70b. 11, the light from the light source 213 and the light from the light guides 301a and 301b do not interfere with each other, so that the movement detection sensor 45 cannot detect the document S accurately. and the problem that unnecessary light may be reflected in the image read by the image reading unit 70a and the image reading unit 70b.

In this embodiment, in order to prevent the light from the light source 213 from interfering with the light from the light guides 301a and 301b, the document is shielded while it is being transported along the transport path. The image reading unit 70b facing the movement detection sensor 45 across the transport path is arranged at a position close to the movement detection sensor 45 in the transport direction so that the movement detection sensor 45 and the transport path are in contact with each other. On the other hand, the image reading unit 70a located on the same side as the image reading unit 70b is arranged on the downstream side in the conveying direction. The combination of is not limited to the example of FIG. 11, and this point is the same as in the first and second embodiments.

Further, in this embodiment, by directing the irradiation directions of the light guides 301a and 301b of the image reading units 70a and 70b to the downstream side in the transport direction, the light can be positioned upstream of the image reading units 70a and 70b. The influence on the arranged movement detection sensor 45 is reduced. However, the irradiation directions of the light guides 301a and 301b of the image reading units 70a and 70b are not limited to this, and may be tilted so that they face the other side or face the other side. Even in this case, by arranging the image reading unit 70b, which is the side shielded by the document, at a position closer to the movement detection sensor 45 than the image reading unit 70a, the above-described mutual influence is reduced. can exert the effect of

Note that the LED 304 may be extinguished while the light source 213 is on.

[Fourth embodiment]
In the first to third embodiments, the document feeding device was described as an example. The present invention can also be applied to a printing apparatus (printer, etc.) that performs printing, or an apparatus having a document conveying system such as a multifunction machine combining these.

A document feeder S document 1 placement table 2 discharge trays 3 and 4 motor 10 first transport section 11a one-way clutch 11b feed roller shaft 12 separation roller 13 pick arm 14 document stopper 20 second transport section 21 transport roller 22 driven roller 30 Third Conveying Section 31 Conveying Roller 32 Driven Roller 40 Double Feed Detection Sensor 41 Transmitting Section 42 Receiving Section 45 Movement Detection Sensors 50, 60 Medium Detection Sensor 51 Light Emitting Section 52 Light Receiving Section 70 Image Reading Unit 80 Control Section 81 CPU
82 Storage unit 83 Operation unit 84 Communication unit 85 Interface unit 86 Actuator 87 Sensor 90 Document detection sensor 110 Feed roller 121 Separation swing member 121a Shaft 122 Compression spring 131 Pick roller 200 Substrate 211 Imaging unit 213 Light source 212a Mold member 212b Mold Member 212c Translucent plate 212 Case body 301 Light guide 303 Rod lens array 304 LED
305 light receiving element 306 substrate 307 sheet

Claims (5)

It has a first light source that irradiates light onto a document conveyed on the conveying path, captures an image of the document by reflected light from the document, and detects the amount or direction of movement of the document based on the image. a detection unit that
a reading unit that has a second light source that irradiates light onto a document transported on the transport path, and that reads the document based on reflected light from the document;
The reading unit is located on the same side of the transport path as the detection unit and on a different side of the transport path from the detection unit at a position shifted downstream from the detection unit in the document transport direction. is provided in
The reading unit on a side different from the detection unit with respect to the transport path is provided closer to the detection unit in the transport direction than the reading unit on the same side as the detection unit with respect to the transport path. An image reading device characterized by: One of the first light source and the second light source provided on the same side as the detection unit with respect to the transport path is the light source with respect to the first light source and the transport path in the direction along the transport path. 2. The image reading apparatus according to claim 1 , wherein the second light source provided on the same side as the detection section emits light toward a side different from the side on which the other is located. The second light source provided on the same side of the transport path as the detector and the second light source provided on the different side of the transport path from the detector are arranged in a direction along the transport path. 3. The image reading apparatus according to claim 1 , wherein light is emitted toward a side different from the side where the first light source is located. 4. The image reading apparatus according to claim 1 , wherein the second light source is turned off while the first light source is turned on. 5. The image reading apparatus according to claim 1 , wherein the image reading apparatus outputs an image of the document read by the reading section.

Images