JP6720726B2 - Image reading device and transportation method - Google Patents

Description

The present invention relates to an image reading device such as a scanner that reads an image of a document, and a conveyance method in the image reading device.

2. Description of the Related Art Conventionally, there is known an image reading apparatus including a feed roller (conveying roller) that conveys a document from an upstream side to a downstream side in the conveying direction and a line sensor (reading unit) that reads an image of the conveyed document. (For example, patent document 1).

In such an image reading apparatus, a pick roller (feeding roller) that feeds an original placed on a sheet placing table (placing section) to a conveyance path, and an original fed by the pick roller are fed one by one. And a separation pad (friction force imparting portion) for separating.

JP, 2005-260387, A

By the way, the separating pad separates the original by pressing the fed original against the pick roller to generate a frictional force acting between the original and the separating pad in a direction opposite to the conveying direction. It was

Therefore, while the original document is located at the sandwiching position where it is sandwiched by the pick roller and the separation pad, a frictional force acts on this original document, but when the original document passes through the sandwiching position, the original document is separated by the separation pad. The friction force due to does not work. Therefore, after the document passes through the pinching position, the document passes through the line sensor at a higher speed, and the length of the image read by the line sensor is shortened.

The present invention has been made in view of these circumstances, and an object thereof is to provide an image reading apparatus and a conveyance method that can reduce a change in the length of an image read by a reading unit.

Hereinafter, the means for solving the above problems and the operation effects thereof will be described.
An image reading apparatus that solves the above-mentioned problems is provided between a feeding roller that feeds the original document from a placing portion on which the original document can be placed toward a conveyance path, and the original document that is fed by the feeding roller. And a feeding portion having a frictional force imparting portion that imparts a frictional force to the opposite side to the feeding direction, and the feeding portion provided downstream of the frictional force imparting portion in the feeding direction. A feeding detection unit that detects the fed document, a conveyance roller that conveys the document fed by the feeding unit from the upstream side to the downstream side in the conveyance direction, and the conveyance roller that conveys the document. A reading unit that reads an image of a document and a control unit that controls driving of the conveyance roller are provided. The control unit conveys the document when the feeding detection unit detects the trailing end of the document. Reduce the transport speed.

According to this configuration, the control unit reduces the conveyance speed when the feeding detection unit detects the trailing end of the document, so that the change in the speed at which the document passes through the reading unit is reduced. Therefore, the change in the length of the image read by the reading unit can be reduced.

In the image reading apparatus, it is preferable that the control unit accelerates the conveyance speed when the trailing edge of the document passes through the reading unit.
For example, if the original document is conveyed at a low conveying speed and the subsequent document is conveyed at a high conveying speed, the succeeding original document may catch up with the original document. In this respect, according to this configuration, since the conveyance speed is increased when the document passes through the reading unit, the throughput can be improved while reducing the influence on the image read by the reading unit.

The image reading device is provided in a position between the feeding detection unit and the reading unit in the conveyance direction, and detects a conveyance detection unit capable of detecting the conveyed document and a rotation number of the conveyance roller. Further comprising a rotation detection unit that controls the speed of the conveyance when the number of rotations detected by the rotation detection unit after the conveyance detection unit detects the rear end of the document exceeds a predetermined number. It is preferable.

With this configuration, it is possible to accurately acquire the position of the document on the transport path based on the detection results of the transport detection unit and the rotation detection unit. Therefore, it is possible to reduce the risk that the transport speed is changed before the document passes through the reading unit.

The image reading apparatus further includes a discharge roller that discharges the document conveyed by the conveyance roller, and the control unit discharges the document by the discharge roller as the conveyance speed is reduced. Is preferably decelerated.

According to this configuration, since the discharge speed is reduced in accordance with the decrease in the transfer speed, the speed difference between the transfer speed and the discharge speed can be reduced. Therefore, it is possible to suitably transfer the document from the transport roller to the discharge roller and transport the document.

In the above-mentioned image reading apparatus, the transport speed is faster than the transport speed at which the feeding unit feeds the document, and the control unit detects that the transport detection unit capable of detecting the transported document detects the document. When the trailing edge is detected, the feeding speed is preferably accelerated.

According to this configuration, when the conveyance detection unit detects the trailing edge of the previously fed document, the control unit accelerates the feeding speed. Therefore, the speed difference between the feeding speed and the conveying speed can be reduced. Therefore, the document fed later can be smoothly delivered from the feeding unit to the transport roller.

A conveyance method for solving the above-mentioned problems is provided between a feeding roller that feeds the document from a placing portion on which the document can be placed toward a conveyance path, and the document fed by the feeding roller. A feeding unit having a frictional force imparting unit for imparting a frictional force to the side opposite to the feeding direction, and a feeding unit provided downstream of the frictional force imparting unit in the feeding direction. A feeding detection unit that detects the fed document, a transport roller that transports the document fed by the feeding unit from the upstream side to the downstream side in the transport direction, and the document transported by the transport roller. A feeding method for feeding the document by the feeding section, and a feeding step for feeding the fed document by the feeding roller. A trailing edge detecting step of causing the feeding detecting section to detect the trailing edge of the original, and a conveying speed at which the conveying roller conveys the original when the trailing edge of the original is detected in the rear edge detecting step. And a deceleration step of decelerating.

According to this configuration, the same effect as that of the image reading apparatus can be obtained.

FIG. 3 is a schematic diagram of an embodiment of an image reading device. FIG. 3 is a schematic diagram of a feeding unit and a feeding detection unit. The block diagram of a control part. 6 is a flowchart of an image reading processing routine. 6 is a timing chart showing a feeding speed and a conveying speed.

Hereinafter, an embodiment of the image reading apparatus will be described with reference to the drawings. The image reading apparatus of the present embodiment is, for example, a sheet feed scanner in which a fixed reading unit reads an image of a conveyed document.

As shown in FIG. 1, the image reading apparatus 11 includes a main body 12 having a substantially trapezoidal box shape in a side view, and a rotating portion 14 that is rotatable around a shaft 13 provided on the main body 12. There is. That is, the rotating portion 14 rotates between the closed position shown by the solid line in FIG. 1 and the open position shown by the chain double-dashed line in FIG.

Further, the image reading apparatus 11 feeds the document D from the placement unit 16 on which a plurality of documents D can be placed in a stacked state, and from the placement unit 16 to the conveyance path 17 indicated by a chain line in FIG. And a feeding unit 18 that operates. The feeding unit 18 includes a feeding roller 19 that feeds the document D and a frictional force applying unit 20 that generates a frictional force between the document D fed by the feeding roller 19 and the document feeding unit 19. Feed D in the feeding direction Y1. The frictional force imparting unit 20 of the present embodiment is a separation roller that rotates in contact with the documents D to separate the documents D from each other.

Further, at a position downstream of the frictional force imparting unit 20 in the transport direction Y2, a transport unit 21 that transports the document D fed by the feeding unit 18 from the upstream side to the downstream side in the transport direction Y2 is provided. ing. The feeding direction Y1 and the transporting direction Y2 in this embodiment are substantially the same. The transport unit 21 has a transport roller 22 that transports the document D, and a transport driven roller 23 that is driven to rotate as the transport roller 22 rotates. Further, the transport roller 22 and the transport driven roller 23 are provided so as to sandwich the transport path 17.

Then, at a position downstream of the transport roller 22 in the transport direction Y2, at least one (a pair in the present embodiment) reading unit 24 that reads the image of the document D transported by the transport roller 22 is provided in the transport path 17. It is provided on both sides so as to extend in the main scanning direction (width direction X).

That is, the reading unit 24 provided in the main body unit 12 reads the image on the first surface (for example, the front surface) of the document D that is transported through the transport path 17 from the upstream side to the downstream side in the transport direction Y2. Further, the reading unit 24 provided in the rotating unit 14 reads the image on the second surface (for example, the back surface) of the document D that is conveyed through the conveyance path 17 from the upstream side to the downstream side in the conveyance direction Y2.

Further, on the downstream side of the reading unit 24 in the transport direction Y2, a discharge roller 25 that discharges the document D transported by the transport roller 22, and a discharge driven roller 26 that rotates by rotation of the discharge roller 25, A discharge unit 27 for discharging the document D is provided.

Further, the image reading apparatus 11 includes a feeding motor 28 that is a driving source for rotating the feeding roller 19 and a conveyance motor 29 that is a driving source for rotating the conveyance roller 22. The transport motor 29 is also connected to the frictional force imparting unit 20 and the discharge roller 25, and also rotates the frictional force imparting unit 20 and the discharge roller 25.

Further, the feeding roller 19, the conveying roller 22, and the discharging roller 25 convey the document D from the upstream side in the feeding direction Y1 and the conveying direction Y2 to the downstream side in accordance with the driving of the feeding motor 28 and the conveying motor 29. It rotates in the normal direction. Then, the frictional force imparting section 20 rotates in reverse so as to impart a frictional force to the side opposite to the feeding direction Y1 with the document D as the transport motor 29 is driven. Further, the transport roller 22 and the discharge roller 25 rotate faster than the feeding roller 19, and the transport roller 22 feeds the document D at a feeding speed (see FIG. 5) Va at which the feeding unit 18 feeds the document D. The carrying speed (see FIG. 5) Vb for carrying is faster. Further, the transport roller 22 and the discharge roller 25 rotate at substantially the same speed, and the discharge speed at which the discharge roller 25 discharges the document D is substantially the same speed as the transport speed Vb.

The image reading device 11 includes a placement detection unit 31 that can detect the document D placed on the placement unit 16, and a feeding unit 18 that is provided downstream of the frictional force imparting unit 20 in the feeding direction Y1. A feeding detection unit 32 capable of detecting the fed document D is provided. Further, the image reading device 11 includes a conveyance detection unit 33 that can detect the conveyed document D and a rotation detection unit 34 that detects the number of rotations of the conveyance roller 22. The conveyance detection unit 33 is provided at a position between the feeding detection unit 32 and the reading unit 24 in the conveyance direction Y2, and at substantially the same position as the conveyance roller 22.

The placement detection unit 31 and the conveyance detection unit 33 are, for example, contact-type sensors having a lever, and detect the presence or absence of the document D when the lever is pressed by the document D. The feeding detection unit 32 is an optical sensor having a light emitting unit 36 that emits light and a light receiving unit 37 that receives the light emitted from the light emitting unit 36.

The rotation detection unit 34 is, for example, a rotary encoder, and detects the scale of the encoder scale 38 that rotates together with the transport roller 22. Further, the image reading device 11 includes a control unit 40 that comprehensively controls driving of each mechanism in the image reading device 11 such as the transport roller 22.

As shown in FIG. 2, in the feeding detection unit 32, the light emitting unit 36 and the light receiving unit 37 are provided at substantially the same position as the feeding roller 19 in the feeding direction Y2 so as to face each other with the feeding path 17 in between. There is. Then, the light emitting section 36 irradiates the detection area A on the transport path 17 with light, and the light receiving section 37 receives the light passing through the detection area A. Therefore, when the document D is located in the detection area A, the light is blocked by the document D, the amount of light received by the light receiving unit 37 decreases, and the feeding detection unit 32 detects the document D.

The feeding detection unit 32 is provided such that the detection area A is located at a position between the sandwiching position P1 and the intersecting position P2 in the transport direction Y2. The nipping position P1 is the position where the feeding roller 19 and the frictional force imparting section 20 nips the document D. Further, the intersecting position P2 is a position where the tangent line T of the feeding roller 19 intersects the conveying path 17 at a right angle on the downstream side of the sandwiching position P1 in the conveying direction Y2.

The tangent line T is also a common tangent line that is in contact with both the side surface of the cylindrical feeding roller 19 and the side surface of the cylindrical frictional force imparting portion 20. That is, the feeding detection unit 32 is arranged such that the detection area A is located on the upstream side in the conveyance direction Y2 with respect to the intersection position P2 which is also the intersection of the common tangent of the feeding roller 19 and the frictional force imparting unit 20 and the conveyance path 17. It is provided in.

The feeding roller 19 and the frictional force imparting portion 20 may be elastically deformed by being formed of, for example, rubber or sponge. That is, the feeding roller 19 and the frictional force imparting portion 20 may be in surface contact with each other. In this case, the downstream end of the surface where the feeding roller 19 and the frictional force imparting portion 20 are in contact with each other in the transport direction Y2 is the nipping position P1, and the feeding detection portion 32 is between the nipping position P1 and the intersecting position P2. It is provided. Therefore, the feeding detection unit 32 detects the document D that has passed through the feeding unit 18.

Next, the electrical configuration of the image reading device 11 will be described.
As shown in FIG. 3, the control unit 40 controls the reading unit 24, the feed motor 28, and the feed motor based on the detection results of the placement detector 31, the feed detector 32, the feed detector 33, and the rotation detector 34. Control the drive of 29.

Next, with reference to the flowchart shown in FIG. 4, a method of conveying the document D in the image reading apparatus 11 will be described based on an image reading processing routine. The image reading processing routine is executed at the timing when a job for reading an image is input.

As shown in FIG. 4, the control unit 40 drives the feeding motor 28 and the conveyance motor 29 in step S101 to cause the feeding unit 18 to feed the document D (feeding process), and the document D is fed. The document D is transported by the transport roller 22 (transport process).

In step S102, the control unit 40 determines whether or not the conveyance detection unit 33 has detected the leading end of the document D (the downstream end in the conveyance direction Y2). Then, when the conveyance detection unit 33 does not detect the document D (step S102: NO), the feeding motor 28 and the conveyance motor 29 are driven and stand by.

When the conveyance detection unit 33 detects the document D, the control unit 40 determines that the leading edge of the document D has been conveyed to the conveyance detection unit 33 (step S102: YES), and stops the feeding motor 28 in step S103. Further, the control unit 40 causes the reading unit 24 to start reading an image in step S104, and causes the feeding detection unit 32 to detect the rear end of the document D in the subsequent step S105 (rear end detection step).

That is, when the feeding detection unit 32 detects the document D, the control unit 40 determines that the document D has not passed the feeding detection unit 32 and waits (step S105: NO). Then, when the detection result of the feeding detection unit 32 changes from the state in which the document D is detected to the state in which the document D is not detected, the control unit 40 determines that the rear end of the document D is detected by the feeding detection unit 32. It is determined (step S105: YES). Further, in step S106, the control unit 40 decelerates the conveyance motor 29 and reduces the conveyance speed Vb at which the conveyance roller 22 conveys the document D (deceleration step).

In step S107, the control unit 40 determines whether the next document D is placed on the placing unit 16 based on the detection result of the placement detecting unit 31. When the document D is placed on the placing section 16 (step S107: YES), the control section 40 drives the feeding motor 28 in step S108, and the process proceeds to step S109. .. When the document D is not placed on the placement unit 16 (step S107: NO), the control unit 40 determines whether the trailing end of the document D has passed the reading unit 24 in step S109. to decide.

That is, when the number of rotations of the transport roller 22 after the transport detection unit 33 detects the rear end of the document D is smaller than a predetermined number of times, the control unit 40 does not pass the rear end through the reading unit 24. And waits (step S109: NO). If the number of rotations of the transport roller 22 after the transport detection unit 33 detects the trailing edge of the document D exceeds a predetermined number (for example, 0.5 rotations), the trailing edge of the document D is read. It is determined that the vehicle has passed (step S109: YES). The predetermined number of times is set according to the model of the image reading apparatus 11, and the distance from the transport roller 22 to the reading unit 24 is the transport amount of the document D transported as the transport roller 22 makes one rotation. It is the value divided by.

Then, the control unit 40 ends the reading of the image by the reading unit 24 in step S110, and accelerates the carry motor 29 in step S111. Further, in step S112, the control unit 40 determines whether the feeding motor 28 is being driven.

When the feeding motor 28 is being driven (step S112: YES), the control unit 40 accelerates the feeding motor 28 in step S113, and the process proceeds to step S102. When the feeding motor 28 is stopped (step S112: NO), the controller 40 stops the carry motor 29 and ends the image reading processing routine in step S114.

Next, regarding the operation of the image reading apparatus 11 configured as described above, the operation when a job for reading an image is input in a state where two originals D are placed on the placing section 16 will be described with reference to FIG. A description will be given based on the timing chart. Further, the placement detection unit 31, the feeding detection unit 32, and the conveyance detection unit 33 output the detection signal S1 when the document D is detected, and output the non-detection signal S2 when the document D is not detected.

Now, as shown in FIG. 5, the control unit 40 drives the feeding motor 28 and the conveyance motor 29 at the first timing t1. Then, the feeding unit 18 feeds the document D at the first feeding speed Va1, and the conveying unit 21 conveys the document D at the first conveying speed Vb1.

When the conveyance detection unit 33 detects the leading edge of the document D at the second timing t2, the control unit 40 stops the feeding motor 28 and sets the feeding speed Va to zero. Since the transport motor 29 is driven at this time, the transport roller 22 transports the document D at the first transport speed Vb1, and the feeding roller 19 rotates along with the document D transported by the transport roller 22. On the other hand, the frictional force applying section 20 rotates in the reverse direction and continues to apply the frictional force to the document D. Then, the reading unit 24 reads the image of the document D at the timing when the document D passes.

When the document D transported by the transport rollers 22 passes through the holding position P1, the frictional force applied by the frictional force imparting unit 20 does not act on the document D, and the feeding detection unit 32 causes the document detection unit 32 to detect the document D. Detect the trailing edge.

At the third timing t3, when the feeding detection unit 32 detects the trailing edge of the document D, the control unit 40 decelerates the carry motor 29. Specifically, the control unit 40 reduces the transport speed Vb at which the transport roller 22 transports the document D from the first transport speed Vb1 to the second transport speed Vb2. The second transport speed Vb2 is a speed that can cancel the change in frictional force that occurs before and after the trailing edge of the document D passes through the holding position P1. Therefore, when the document D to which the frictional force imparting unit 20 imparts the frictional force is conveyed at the first conveying speed Vb1, the speed at which the document D passes through the reading unit 24 and the document on which the frictional force by the frictional force imparting unit 20 does not act. When D is transported at the second transport speed Vb2, the speed at which the document D passes through the reading unit 24 is substantially the same.

Since the transport roller 22 also rotates the discharge roller 25 and the frictional force imparting unit 20, the discharge speed at which the discharge roller 25 discharges the document D and the rotation speed of the frictional force imparting unit 20 are also reduced in accordance with the transport speed Vb. .. That is, the control unit 40 reduces the discharge speed in accordance with the decrease in the transport speed Vb.

Further, at the third timing t3, the placement detector 31 detects the next document D, so at the fourth timing t4 when a predetermined time has elapsed from the third timing t3, the controller 40 causes the feeding motor 28 to move. Drive. The predetermined time is a time that is set according to the model of the image reading device 11 and the type of the document D, and is such that the document D fed first and the document D fed later do not overlap. It is set to time (for example, 1 second).

When the conveyance detection unit 33 detects the trailing edge of the document D at the fifth timing t5, the control unit 40 waits until the trailing edge of the document D passes through the reading unit 24 and sets the conveyance speed Vb and the feeding speed Va. To accelerate. Specifically, the control unit 40 causes the rotation number detected by the rotation detection unit 34 after the conveyance detection unit 33 detects the rear end of the document D to exceed a predetermined number of times, and the rear end of the document D causes the reading unit 24 to move. At the passed sixth timing t6, the carry motor 29 is accelerated. That is, the transport speed Vb is accelerated from the second transport speed Vb2 to the first transport speed Vb1.

When the transport speed Vb reaches the first transport speed Vb1 at the seventh timing t7, the control unit 40 accelerates the feed motor 28 to change the feed speed Va from the first feed speed Va1 to the second feed speed Va2. To accelerate.

When the conveyance detector 33 detects the leading edge of the document D at the eighth timing t8, the controller 40 stops the feeding motor 28 and sets the feeding speed Va to zero.
When the feeding detection unit 32 detects the trailing edge of the document D at the ninth timing t9, the control unit 40 decelerates the conveyance motor 29 and decelerates the conveyance speed Vb from the first conveyance speed Vb1 to the second conveyance speed Vb2. Let Further, at this time, since the placement detector 31 has not detected the document D, the controller 40 does not drive the feeding motor 28.

When the conveyance detection unit 33 detects the trailing edge of the document D at the tenth timing t10, the control unit 40 waits until the trailing edge of the document D passes through the reading unit 24, and causes the transportation motor 29 to operate at the eleventh timing t11. To accelerate. Then, at the twelfth timing t12, when the transport speed Vb is accelerated to the first transport speed Vb1 and the document D is discharged to the discharge unit 27, the control unit 40 stops the transport motor 29 and sets the transport speed Vb to zero. To

According to the above embodiment, the following effects can be obtained.
(1) Since the control unit 40 reduces the conveyance speed Vb when the feeding detection unit 32 detects the trailing edge of the document D, the change in the speed at which the document D passes through the reading unit 24 is reduced. Therefore, the change in the length of the image read by the reading unit 24 can be reduced.

(2) For example, if the original document D is conveyed at the low conveying speed Vb and the succeeding original document D is conveyed at the high conveying speed Vb, the succeeding original document D may catch up with the preceding original document D. In this respect, since the conveyance speed Vb is increased when the document D passes through the reading unit 24, the throughput can be improved while reducing the influence on the image read by the reading unit 24.

(3) The position of the document D in the transport path 17 can be accurately acquired based on the detection results of the transport detection unit 33 and the rotation detection unit 34. Therefore, it is possible to reduce the risk that the transport speed Vb is changed before the document D passes through the reading unit 24.

(4) Since the discharge speed is reduced in accordance with the decrease in the transfer speed Vb, the speed difference between the transfer speed Vb and the discharge speed can be reduced. Therefore, it is possible to preferably transfer the document D from the transport roller 22 to the discharge roller 25 and transport the document D.

(5) When the conveyance detection unit 33 detects the trailing edge of the document D fed earlier, the control unit 40 accelerates the feeding speed Va. Therefore, the speed difference between the feeding speed Va and the conveying speed Vb can be reduced. Therefore, the document D fed later can be smoothly transferred from the feeding unit 18 to the transport roller 22.

(6) For example, when the feeding roller 19 starts rotating at a high speed, the feeding roller 19 may slip with respect to the document D, and the document D may not be fed. In this respect, since the control unit 40 accelerates the feeding speed Va after the feeding is started, it is possible to reduce the risk that the document D is not fed.

The above embodiment may be modified as follows.
In the above embodiment, the placement detection unit 31, the feeding detection unit 32, the conveyance detection unit 33, and the rotation detection unit 34 may be any detection unit such as a contact type or a non-contact type. For example, the feeding detection unit 32 may be a contact type sensor having a lever. Further, for example, the transport detection unit 33 may be an optical sensor. Further, the feeding detection unit 32 and the conveyance detection unit 33 may be an image sensor that detects the document D by image processing or an ultrasonic sensor that detects the document D according to the degree of attenuation of the ultrasonic waves.

-In above-mentioned embodiment, the 1st conveyance speed Vb1 may be the same speed as the 1st feeding speed Va1.
In the above embodiment, the control unit 40 does not have to accelerate the feeding speed Va even if the conveyance detection unit 33 detects the trailing edge of the document D. That is, the control unit 40 does not have to accelerate the feeding speed Va at the seventh timing t7 shown in FIG. Further, the control unit 40 accelerates the feeding speed Va at the fifth timing t5 when the conveyance detection unit 33 detects the trailing end of the document D and the sixth timing t6 when the trailing end of the document D passes through the reading unit 24. You may let me.

In the above embodiment, the discharge roller 25 and the discharge driven roller 26 may not be provided.
In the above embodiment, the discharge speed may be constant regardless of the transport speed Vb. That is, for example, as compared with the pressure at which the transport roller 22 and the transport driven roller 23 clamp the document D, the pressure at which the discharge roller 25 and the discharge driven roller 26 clamp the document D are weakened, and the transport speed Vb is reduced. In this case, the discharge roller 25 and the document D may be slid.

In the above embodiment, at least one of the conveyance detection unit 33 and the rotation detection unit 34 may not be provided. For example, the control unit 40 may determine that the rear end of the document D has passed the reading unit 24 when a predetermined time has elapsed since the conveyance detection unit 33 detected the rear end of the document D.

In the above embodiment, even if the trailing edge of the document D passes through the reading unit 24, the conveyance speed Vb does not have to be accelerated. That is, the conveyance speed Vb does not have to be accelerated at the sixth timing t6 and the eleventh timing t11. When the next document D is being fed, the conveyance speed Vb may be accelerated between the sixth timing t6 and the eighth timing t8. Further, at the eleventh timing t11 when the trailing edge of the last document D passes through the reading unit 24, the transport motor 29 may be stopped as it is.

In the above embodiment, the frictional force imparting unit 20 may be a separation pad that holds the document D together with the feeding roller 19 and separates the documents D from each other.
In the above embodiment, the image reading device 11 is not limited to the sheet feed type, and may be a flat bed type image reading device including an automatic document feeding device (auto sheet feeder) that automatically feeds the document D. .. Further, the image reading device 11 may be applied to a multi-function device integrated with a printing device, a FAX having a communication function, or the like.

A... Detection area, D... Original, P1... Nip position, P2... Crossing position, S1... Detection signal, S2... Non-detection signal, T... Tangent line, Va... Feed speed, Va1... First feed speed, Va2... 2nd feeding speed, Vb... conveyance speed, Vb1... 1st conveyance speed, Vb2... 2nd conveyance speed, Y1... feeding direction, Y2... conveyance direction, t1-t12... 1st timing-12th timing, 11... Image reading device, 12... Main body part, 13... Shaft, 14... Rotating part, 16... Placement part, 17... Conveying path, 18... Feeding part, 19... Feeding roller, 20... Friction force applying part, 21 ...Conveying section, 22...conveying roller, 23...conveying driven roller, 24...reading section, 25...ejection roller, 26...ejection driven roller, 27...ejection section, 28...feeding motor, 29...conveying motor, 31...mounting Position detector, 32... Feeding detector, 33... Conveyance detector, 34... Rotation detector, 36... Light emitting unit, 37... Light receiving unit, 38... Encoder scale, 40... Control unit.

Claims (5)

Between the feeding roller that feeds the original document from the placing portion on which the original document can be placed toward the conveyance path, and the original document that is fed by the feeding roller, in the direction opposite to the feeding direction. A feeding unit having a frictional force imparting unit that imparts a frictional force, and
A feeding detection unit that is provided on the downstream side of the frictional force imparting unit in the feeding direction and that detects the document fed by the feeding unit,
A transport roller that transports the document fed by the feeding unit from the upstream side to the downstream side in the transport direction,
A reading unit for reading an image of the original document conveyed by the conveyance roller;
A control unit for controlling the drive of the transport roller,
When the feeding detection unit detects the rear end of the document, the control unit reduces the conveyance speed at which the conveyance roller conveys the document, and when the rear end of the document passes through the reading unit, the conveyance speed is changed. image reading apparatus according to claim Rukoto was accelerated. A conveyance detection unit which is provided at a position between the feeding detection unit and the reading unit in the conveyance direction and is capable of detecting the conveyed document;
And a rotation detection unit that detects the number of rotations of the transport roller,
Wherein, in claim 1 the rotational speed of the rotation detecting unit detects the conveyance detection unit from the detection of the rear end of the document is characterized in that to accelerate the conveying speed After exceeds a predetermined number of times The image reading device described. Further comprising a discharge roller for discharging the original document transported by the transport roller,
Wherein the control unit includes an image reading apparatus according to claim 1 or claim 2 wherein the discharge roller fit to decelerate the transport speed is equal to or decelerating the discharge speed for discharging the original document. The conveyance speed is faster than the feeding speed at which the feeding unit feeds the document,
Wherein the control unit, any one of the claims 1 to 3, characterized in that the document conveyed conveyance detection unit capable of detecting to accelerate the feed rate and detecting a trailing edge of the document The image reading device according to item. Between the feeding roller that feeds the original document from the placing portion on which the original document can be placed toward the conveyance path, and the original document that is fed by the feeding roller, in the direction opposite to the feeding direction. A feeding unit having a frictional force imparting unit that imparts a frictional force, and
A feeding detection unit that is provided on the downstream side of the frictional force imparting unit in the feeding direction and that detects the document fed by the feeding unit,
A transport roller that transports the document fed by the feeding unit from the upstream side to the downstream side in the transport direction,
And a reading unit that reads an image of the document conveyed by the conveyance roller,
A feeding step of feeding the original by the feeding section,
A conveying step of conveying the fed original by the conveying roller,
A trailing edge detecting step of causing the feeding detecting section to detect the trailing edge of the document,
When the trailing edge of the document is detected in the trailing edge detection step, a deceleration step of decelerating the transport speed at which the transport roller transports the document ,
And a accelerating step of accelerating the transportation speed when the trailing edge of the document passes through the reading unit .

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