JP2001245105A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for reducing operating time, and to increase efficiency at double-sided reading of an original. SOLUTION: The face side reader 21 reads image data on the one side surface of the original copy at transferring it in the forward direction by second conveying roller pair 19 and so on with related devices and after finishing of its reading, the copy is transferred in the backward direction by the roller pair 19 and so on. Then the is copy re-transferred in the forward direction, and the backside reader 23 reads image data one other side of the copy. In an image read part 2, the transfer rate of the copy at reading of image data is V1 and the transfer rate of the copy at reverse direction is V2, then the relation for both transfer rate becomes, V1<=V2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus capable of reading image information on both sides of a document, and more particularly, to an image reading apparatus used in, for example, a copying machine, a facsimile apparatus, or a composite apparatus thereof. It is about.

[0002]

2. Description of the Related Art Conventionally, there are the following image reading apparatuses capable of reading image information on both sides of a document.

[0003] For example, 2
2. Description of the Related Art There is an image reading apparatus that simultaneously reads image information on both sides of a document by one reading unit with one pass (hereinafter, referred to as “prior art 1”).

Further, there is an image reading apparatus in which a document is switched back and image information of the document is read one by one by two reading means opposed to each other with a document contact roller interposed therebetween (hereinafter, referred to as an image reading apparatus).
"Prior art 2").

[0005]

However, the conventional image reading apparatus has the following problems.

In the prior art 1, since the two reading means are operated at the same time, the time required for reading both sides of the document is shorter than that for reading one side at a time. However, image processing for processing image information read by the reading means is required. Means are each (2
One) and cost increases. Furthermore, when an apparatus with a single-sided reading function as a standard function and a double-sided reading function as an option is to be developed, a single-sided reading function requires two image processing means in advance even in a standard type apparatus having a single-sided reading function. The cost merit of a device with functions is unlikely to appear.

On the other hand, in the prior art 2, the image information of the document is read one side at a time by two reading means. After reading the image information on one side, the document returned by switchback is read on the other side. Is read in the direction opposite to that of the previous surface. For example, when transmitting as a FAX image, information in which the vertical direction of the image is different for each page is transmitted. In order to avoid this, an image inverting means for inverting the read image upside down or a document inverting means for inverting the original upside down is required, which complicates the apparatus configuration.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to reduce the operation time for double-sided reading and increase the efficiency with a low cost and simple configuration. .

[0009]

In order to achieve the above object, a typical configuration of the present invention is a document transport means capable of transporting a document in forward and reverse directions, and a guide for a document transported by the document transport means. A document feed path, a first reading unit provided in the document feed path for reading image information on one side of the document, and a second reading means provided in the document feed path for reading image information on the other side of the document. Reading means for reading the image information on one side by the first reading means while the original is conveyed in the forward direction by the original conveying means, and after the image reading on one side is completed, the original by the original conveying means. In the image reading apparatus for reading the image information on the other surface by the second reading means while conveying the original in the forward direction again by the original feeding means, , The document transportation speed when reading image information V1, when the conveyance speed when conveying the original in the reverse direction is V2, both the conveying velocity relationship, V1 ≦ V
2.

According to the above construction, the transport speed V2 for transporting the document in the reverse direction is faster than the transport speed V1 for reading the image. It is possible to increase efficiency.

A document transport means capable of transporting a document in forward and reverse directions, a document transport path for guiding the document transported by the document transport means, and a document feed path provided in the document transport path and having A first reading unit that reads image information; and a second reading unit that is provided in the document conveyance path and reads image information of the other surface of the document.The document conveyance unit conveys the document in a forward direction. Reading the image information on one side by the first reading means, conveying the original in the reverse direction by the original conveying means after the image reading on one side is completed, and then again moving the original in the forward direction by the original conveying means. In the image reading apparatus for reading the image information on the other side by the second reading means while conveying the original, the original is arranged upstream of at least one of the reading means with respect to the conveying direction of the original in the forward direction. And a pair of document conveying rollers constituting the document conveying means is disposed upstream of the document detecting means, and the conveying speed when conveying the document in the reverse direction is set to V2. Further, when the original is transported in the reverse direction at the transport speed V2, the time required from when the edge of the original reaches the original detecting means to when the edge of the original is detected is t2, and when the original is transported from the transport speed V2. Assuming that the transport distance required to stop is l2 and the distance between the document transport roller pair and the document detecting means is l1, the distance l1 between the document transport roller and the document detecting means is l1. > V2 × t2 + l2.

According to the above arrangement, the distance l1 between the document conveying roller pair and the document detecting means is set to the reverse conveying distance V2.times.t from when the end of the document reaches the document detecting means until it is stopped.
By making the length longer than 2 + l2, it is possible to prevent the original from falling out of the original conveying roller pair and being unable to be re-conveyed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image reading apparatus to which the present invention is applied will be described in detail with reference to the drawings.

[First Embodiment] Referring to FIGS. 1 to 13,
The image reading device according to the first embodiment will be described in detail. In the present embodiment, a configuration of an image reading apparatus in a facsimile apparatus will be described as an example.

FIG. 2 is an external perspective view of the facsimile machine. In FIG. 2, reference numeral 1 denotes an apparatus main body, 2 denotes an image reading unit according to the present invention disposed at an upper portion of the apparatus main body 1, 3 denotes an image forming unit disposed at a lower portion of the apparatus main body 1, and 11 denotes a document D. A document mounting table 25 is a document discharge tray.

FIG. 1 is a schematic sectional view showing a schematic configuration of an image reading section in a facsimile apparatus. In FIG.
Reference numeral 12 denotes a document presence / absence detection sensor for detecting that the document D has been set on the document table 4; 13 a pickup roller for feeding the set document D into the image reading unit 2;
Reference numeral 15 denotes a separating roller and a reverse roller for separating and feeding the originals D fed in cooperation one by one, and 16 denotes a separated original D.
A document feed sensor for detecting the leading edge and the trailing edge of the document, 17 is a first transport roller pair for transporting the separated document D to a U-turn path 18 which is a U-turn-shaped transport path, and 19 is a document roller after the U-turn. Surface reading unit composed of an image sensor
A pair of forward and reverse rotatable second transport rollers for transporting the document 21; a document edge sensor 20 for detecting a leading edge and a trailing edge of the document D in order to time the start and end of reading of the document; A reverse rotation path serving as a transport path, 23 is a back surface reading unit composed of a contact type image sensor, 24 is a forward / reverse rotatable discharge roller pair that discharges the read original to the original discharge tray 25, and 26 is Pickup roller 13, separation roller
14, a reverse motor 15, a first transport roller pair 17, a second transport roller pair 19, a drive motor for driving the paper discharge roller pair 24, a pickup roller 13, a separation roller 14, and a drive motor 26 for the reverse roller 15 This is an electromagnetic clutch that temporarily shuts off driving.

In the following description with reference to FIGS. 4 to 13, V1 denotes a document conveying speed set for reading, and V1
Reference numeral 2 denotes a reverse rotation speed higher than the set document conveyance speed V1, and t2 denotes a time from when the document edge reaches the document edge sensor 20 when the document is conveyed at the reverse rotation speed V2 until the document edge is detected. Time, l1 is the second transport roller pair
The distance 12 between the document edge sensor 19 and the document edge sensor 20 is the distance required to stop the document from the reverse transport speed V2.

Although not shown, the image reading unit 2 is configured to be appropriately controlled by a control circuit (control means). For example, an image processing circuit (image processing means) for processing image information of the document D read by the front side reading unit 21 and the back side reading unit 23, and an input source of image information to the image processing circuit is the front side reading unit 21 Alternatively, it controls a switching circuit (switching means) for switching to the back surface reading unit 23. Alternatively, the pickup roller 13, the separation roller 14, the reverse rotation roller 15, and the first transport roller pair 17, the second transport roller pair 19, and the paper discharge roller pair 24 that constitute the document transport unit are rotated. Drive motor to drive
26, ON / OFF of an electromagnetic clutch 27 for temporarily interrupting the drive of the drive motor 26 to the pickup roller 13, the separation roller 14, and the reversing roller 15, the front surface reading unit 21 and the back surface The reading start / end timing of the reading unit 23 is controlled based on detection signals from the above-described document presence / absence detection sensor 12, document feed sensor 16, document edge sensor 20, and the like.

Next, the operation of the image reading section 2 will be described with reference to FIGS. 4 to 13 based on a flowchart shown in FIG.

When the user sets the document D on the document table 4 (S101), the document presence / absence detection sensor 12 detects this (S102, see FIG. 4).

The user selects double-sided reading and instructs to start reading (S103). When single-sided reading is selected,
The process proceeds to a well-known one-side reading operation (detailed description is omitted).

When an instruction to start reading is received, the electromagnetic clutch
27 is the pickup roller 13, separation roller 14, reverse roller
The drive to 15 is connected (S104).

The drive motor 26 rotates in the forward direction (S10).
5), the pickup roller 13 comes into contact with the document D set on the document mounting table 11 and starts picking up and transporting the document D into the apparatus (S106).

The document D picked up and conveyed is separated by the separation roller 14 and the reverse rotation roller 15, and one uppermost document is separated and fed (S107, see FIG. 5). At this time, the conveyance speed of the separation roller 14 is lower than the set document conveyance speed V1 because the conveyance speed is suppressed by the reverse rotation roller 15 in order to suppress the damage of the document at the time of separation.

When the document feed sensor 16 detects the leading edge of the document D (S108), the conveyance of the document by the pickup roller 13 is released (S109, see FIG. 6).

Then, the document D separated into one sheet is transported to the U-turn path 18 by the first transport roller pair 17 having a peripheral speed higher than the set document transport speed V1 (S110).
At this time, the delay in the separation roller 14 and the reverse rotation roller 15 is canceled by the first conveying roller pair 17, and the original is conveyed at the substantially set original conveying speed V1. The peripheral speed of the first conveying roller pair 17 is set in advance to a speed that cancels out the delay at the separation roller 14 and the reverse rotation roller 15.

Then, the document D is transported by the second transport roller pair 19 having a substantially set peripheral speed of the document transport speed V1, and the document edge sensor 20 detects the leading edge of the document D (S
111), and when a predetermined amount is conveyed from there,
The reading of the front side of the original by 1 is started (S112, see FIG. 7). The document is transported at a substantially set document transport speed V1. The peripheral speed of the discharge roller pair 24 is set at the set document transport speed V
Set slightly faster than 1 and the transfer force is
Set lower than 19. When the conveyance of the document by the discharge roller pair 24 is started, the document is tensioned by a slight peripheral speed difference between the second conveyance roller pair 19 and the discharge roller pair 24, and the front surface reading unit 21 and the back surface reading unit 23 The document is conveyed at a position most suitable for reading by the scanner. Further, the peripheral speed difference between the second transport roller pair 19 and the discharge roller pair 24 is small, and the discharge roller pair 24
Is set lower than the second conveying roller pair 19, the document is conveyed at this time at the substantially set document conveying speed V1.

When the document feed sensor 16 detects the trailing end of the document D (S113), the electromagnetic clutch 27 cuts off the driving of the pickup roller 13, separation roller 14, and reverse rotation roller 15, and the next document is not conveyed. It stops (S114, see FIG. 8).

When the document edge sensor 31 detects the trailing end of the document D (S115), when the document is conveyed by a predetermined amount, the reading of the front surface of the document by the front surface reading section 21 is completed (S116, see FIG. 9).

After reading the original surface, the drive motor 26
Is rotated in the opposite direction (S117), and the document is
The document is conveyed in the reverse direction by the pair of sheet discharge rollers 9 and at a reverse rotation speed V2 higher than the substantially set document conveyance speed V1, and is conveyed to the reverse rotation path 22 by the shape of the junction of the U-turn path 18 and the reverse rotation path 22. (S118, see FIG. 10). At this time, since the document is conveyed at the reverse rotation conveyance speed V2 higher than the substantially set document conveyance speed V1 (V1 ≦ V2), the processing speed in double-sided reading is increased, and work efficiency can be improved. Note that the original is slightly loosened between the rollers due to the peripheral speed difference between the pair of second transport rollers 19 and the pair of discharge rollers 24, but the front-side reading unit 21 and the back-side reading unit 23 do not read the image. There is no effect on

Document edge sensor 20 and second transport roller pair 19
Is greater than the distance V2 × t2 conveyed by the time when the document edge sensor 20 detects the end of the document, and the distance l2 required to stop the document from the reverse transport speed V2. Is also set long (11> V2 ×
At time t2 + l2), the document does not fall out of the second transport roller pair 19 and cannot be transported again.

When the document edge sensor 20 detects the passage of the edge of the document D (S119, see FIG. 11), the reverse transport of the document is stopped. Then, the drive motor 26 rotates in the forward direction again (S120). At this time, since the document has been further transported to a predetermined position after passing through the discharge roller pair 24, slack of the document has been eliminated.

When the document edge sensor 20 detects the edge of the document D again (S121), when the document is conveyed by a predetermined amount from the edge, the reading of the back surface of the document by the back surface reading unit 23 is started (S122, see FIG. 12). The document transport state is determined by the first transport roller pair 17 set at a speed (substantially set document transport speed V1) that cancels out the delay at the separation roller 14 and the reverse rotation roller 15.
The document is conveyed by both the pair of second conveying rollers 19 having a substantially set peripheral speed of the document conveying speed V1 (when reading the front side of the document), or the pair of second conveying rollers having a substantially set peripheral speed of the document conveying speed V1 Although there is a difference between whether the document is conveyed only at the time of 19 (when reading the back of the document), the document conveyance speed V
1, the document conveyance speed when reading the back side of the document is the same as when reading the front side of the document.

When the document edge sensor 20 detects the trailing end of the document D (S123), when the document D is conveyed by a predetermined amount, the reading of the back surface of the document by the back surface reading unit 23 is completed (S123).
124), the original D is discharged by the discharge tray 25 by the discharge roller pair 24.
(S125, see FIG. 13). Discharge roller pair 24
Is set to a peripheral speed slightly higher than the set document conveying speed V1, thereby preventing the document from being loosened in the front surface reading unit 21 and the back surface reading unit 23.

If the document presence / absence detection sensor 12 has detected the document D, the process returns to step S104, and the electromagnetic clutch 27 is connected to the pickup roller 13 and the separation roller 1 as described above.
4. The drive to the reverse rotation roller 15 is connected, and the next original is conveyed. If no detection is detected, the reading operation is terminated (S12).
6).

As described above, according to the present embodiment, the reverse transport speed V2, which is the transport speed when the original is transported in the reverse direction, is set to be lower than the substantially set original transport speed V1, which is the transport speed at the time of image reading. , The operation time for double-sided reading can be reduced, and efficiency can be increased.

Since the distance l1 (see FIG. 4) between the second pair of transport rollers 19 and the document edge sensor 20 is longer than the reverse transport distance V2 × t2 + l2 after the detection of the document edge sensor, the document D Can be prevented from slipping out of the nip portion of the second transport roller pair 19 and being unable to re-transport the document D by the second transport roller pair 19.

[Second Embodiment] Referring to FIGS. 14 to 25,
The image reading device according to the second embodiment will be described in detail. In the present embodiment, a configuration of an image reading apparatus in a facsimile apparatus will be described as an example.

In the following description, members having substantially the same functions as those constituting the apparatus of the above-described embodiment are denoted by the same reference numerals.

FIG. 14 is a schematic sectional view showing a schematic configuration of an image reading section in a facsimile apparatus. In FIG.
11 is a document table for setting the document D, and 12 is a document D
, A document detection sensor for detecting that the document D is set on the document table 4, a pickup roller 13 for feeding the set document D into the image reading section 2, and a document D fed in cooperation with 14 and 15. A separation roller and a reverse rotation roller for separating and feeding the document D one by one; a document feed sensor 16 for detecting the leading and trailing edges of the separated document D; and 17 a U-turn shaped conveyance path for the separated document D. A first transport roller pair for transporting to the U-turn path 18, 19 is a second transport roller pair for transporting the document D after the U-turn to the front surface reading unit 21 configured by the close contact type image sensor, and 31 is a document for the front surface reading unit 21. The first document edge sensor 32 detects the leading edge and the trailing edge of the document D in order to measure the timing of the start and end of the reading of the front surface. Third transport roller pair Reference numerals 33 and 33 denote transport path switching which is opened when the original document enters from the forward direction (arrow P direction), and is cut off when the original document enters from the reverse direction (arrow Q direction) to guide the original document to the reverse rotation path 34. A flapper 35 is a second document edge sensor that detects the leading edge and the trailing edge of the document D in order to measure the timing of starting and ending the reading of the back side of the document by the back side reading unit 23 composed of a contact type image sensor. A pair of discharge rollers capable of normal and reverse rotation for discharging the completed document to the document discharge tray 25, a pickup roller 13, a separation roller 14, a reverse rotation roller 15, a first transport roller pair 17, and a second transport roller pair 19 And a drive motor 27 for driving the third transport roller pair 32 and the paper discharge roller pair 24, and an electromagnetic clutch 27 for temporarily interrupting the drive of the drive motor 26 to the pickup roller 13, the separation roller 14, and the reverse rotation roller 15.

In the following description with reference to FIGS. 16 to 25, V1 is a document conveying speed set for reading,
Reference numeral 2 denotes a reverse transport speed higher than the set document transport speed V1, and t2 denotes a time from when the document edge reaches the second document edge sensor 35 when the document is transported at the reverse transport speed V2 until the document edge is detected. Is the distance between the third conveying roller pair 32 and the second document edge sensor 35, and l2 is the distance required to stop the document from the reverse conveying speed V2.

Although not shown, the image reading section 2 is configured to be appropriately controlled by a control circuit (control means). For example, an image processing circuit (image processing means) for processing image information of the document D read by the front side reading unit 21 and the back side reading unit 23, and an input source of image information to the image processing circuit is the front side reading unit 21 Alternatively, it controls a switching circuit (switching means) for switching to the back surface reading unit 23. Alternatively, a pickup roller 13, a separation roller 14, a reverse rotation roller 15, and a first transport roller pair 17, a second transport roller pair 19, and a third transport roller pair 32 that constitute an original transport unit and an original transport unit. An electromagnetic clutch 27 that temporarily cuts off the drive and drive switching of a drive motor 26 that rotationally drives the discharge roller pair 24 and the drive of the drive motor 26 to the pickup roller 13, the separation roller 14, and the reverse rotation roller 15.
ON / OFF, and further, the start / end timing of reading by the front side reading unit 21 and the back side reading unit 23 are determined by the above-described document presence / absence detection sensor 12, document feed sensor 16, first document edge sensor 31, and second document edge. The control is performed based on a detection signal from the sensor 35 or the like.

Next, the operation of the image reading section 2 will be described with reference to FIGS. 16 to 25 based on the flowchart shown in FIG.

When the user sets the document D on the document table 4 (S201), the document presence / absence detection sensor 12 detects it (S202, see FIG. 16).

The user selects double-sided reading and instructs to start reading (S203). When single-sided reading is selected,
The process proceeds to a well-known one-side reading operation (detailed description is omitted).

When an instruction to start reading is received, the electromagnetic clutch
27 is the pickup roller 13, separation roller 14, reverse roller
The drive to 15 is connected (S204).

The drive motor 26 rotates in the forward direction (S20).
5), the pickup roller 13 comes into contact with the document D set on the document placing table 11 and starts picking up and transporting the document D into the apparatus (S206).

The document D picked up and conveyed is separated by the separation roller 14 and the reverse rotation roller 15, and one uppermost document is separated and fed (S207, see FIG. 17). At this time, the conveyance speed of the separation roller 14 is lower than the set document conveyance speed V1 because the conveyance speed is suppressed by the reverse rotation roller 15 in order to suppress the damage of the document at the time of separation.

When the document feed sensor 16 detects the leading edge of the document D (S208), the conveyance of the document by the pickup roller 13 is released (S209, see FIG. 18).

Then, the document D separated into one sheet is transported to the U-turn path 18 by the first transport roller pair 17 having a peripheral speed higher than the set document transport speed V1 (S210).
At this time, the delay in the separation roller 14 and the reverse rotation roller 15 is canceled by the first conveying roller pair 17, and the original is conveyed at the substantially set original conveying speed V1. The peripheral speed of the first conveying roller pair 17 is set in advance to a speed that cancels out the delay at the separation roller 14 and the reverse rotation roller 15.

Then, the original D is transported by the second transport roller pair 19 and the third transport roller pair 32 having a substantially set peripheral speed of the original transport speed V1, and the first original edge sensor 31 detects the leading edge of the original D. Then, when the document is conveyed by a predetermined amount from that position (S211), reading of the front side of the document by the front side reading unit 21 is started (S212, see FIG. 19). The document is transported at a substantially set document transport speed V1. The peripheral speed of the discharge roller pair 24 is set slightly higher than the set document conveyance speed V1, and the conveyance force is set lower than that of the third conveyance roller pair 32.
When the document transport by the discharge roller pair 24 is started, the document is tensioned by a slight peripheral speed difference between the third transport roller pair 32 and the paper discharge roller pair 24. However, since the peripheral speed difference between the third pair of conveying rollers 32 and the pair of discharging rollers 24 is small and the conveying force is set to be lower than that of the third pair of conveying rollers 32, the document is also substantially set at this time. The document is transported at the determined document transport speed V1.

When the document feed sensor 16 detects the trailing end of the document D (S213), the electromagnetic clutch 27 cuts off the driving of the pickup roller 13, the separation roller 14, and the reverse roller 15, and the next document is not conveyed. Stop (S214, FIG. 2)
0).

When the first document edge sensor 31 detects the trailing end of the document D (S215), when the document is conveyed by a predetermined amount, the reading of the document surface by the front surface reading unit 21 ends (S216).

When the document D is further conveyed further downstream by the third conveying roller pair 32 and its rear end passes through the conveyance path switching flapper 33 (S217, see FIG. 21), the drive motor 26
Rotates in the opposite direction (S218).

Then, the document D is transferred to the third transport roller pair 32.
Then, the paper is conveyed in the reverse direction by the paper discharge roller pair 24, and guided to the reverse rotation path 34 by the conveyance path switching flapper 33 (S21).
9, see Figure 22). At this time, the document conveyance speed V which is substantially set
(V1)
.Ltoreq.V2), the processing speed in double-sided reading is increased, and the working efficiency can be increased. Note that the document loosens slightly between the third transport roller pair 32 and the paper discharge roller pair 24 due to the peripheral speed difference between the rollers.
Has not been read, so there is no effect on the image.

The distance 11 between the second document edge sensor 35 and the third transport roller pair 32 is a distance V2 × t2 that is transported until the second document edge sensor 35 detects the edge of the document,
Since the distance is set to be longer than the reverse transport speed V2 plus the distance l2 required to stop the original (l1
> V2 × t2 + l2), so that the original does not fall out of the third transport roller pair 32 and cannot be transported again.

When the second document edge sensor 35 detects the passage of the edge of the document D (S220), the reverse conveyance of the document is stopped. Then, the drive motor 26 rotates in the forward direction again (S
221, see FIG. 23). At this time, since the document has been further transported to a predetermined position after passing through the discharge roller pair 24, slack of the document has been eliminated.

The second original edge sensor 35 detects the original D again.
Is detected (S222), reading of the back surface of the document by the back surface reading unit 23 is started when the predetermined amount is conveyed from there (S223, see FIG. 24). The peripheral speed of the discharge roller pair 24 is set slightly higher than the set document conveyance speed V1, and the conveyance force is set lower than that of the third conveyance roller pair 32.
When the document transport by the discharge roller pair 24 is started, the document is tensioned by a slight peripheral speed difference between the third transport roller pair 32 and the paper discharge roller pair 24, and is most likely to be read by the back surface reading unit 23. The document is transported at a suitable position. Further, since the peripheral speed difference between the third conveying roller pair 32 and the discharge roller pair 24 is small, and the conveying force of the discharge roller pair 24 is set lower than that of the third conveying roller pair 32, Also at this time, the original is conveyed at a substantially set original conveying speed V1.

When the second document edge sensor 35 detects the trailing edge of the document D (S224), when the document is conveyed by a predetermined amount therefrom, the reading of the back surface of the document by the back surface reading unit 23 is completed (S225). Is discharged to the discharge tray 25 by the discharge roller pair 24 (S226, see FIG. 25). Paper output roller pair 2
By setting 4 to a peripheral speed higher than the set document conveying speed V1, the document is prevented from being loosened in the front-side reading unit 21 and the back-side reading unit 23.

If the document presence detection sensor 12 has detected the document D, the process returns to step S204, and the electromagnetic clutch 27 is connected to the pickup roller 13 and the separation roller 1 as described above.
4. The drive to the reverse rotation roller 15 is connected, and the next original is conveyed. If no detection is detected, the reading operation is terminated (S22).
7).

As described above, also in this embodiment,
Similarly to the above-described embodiment, the reverse transport speed V2, which is the transport speed when transporting the document in the reverse direction, is faster than the substantially set document transport speed V1, which is the transport speed at the time of image reading. The operation time during double-sided reading can be shortened, and efficiency can be increased.

Further, the distance 11 (see FIG. 14) between the third pair of conveying rollers 32 and the second document edge sensor 35 is longer than the reverse conveying distance V2 × t2 + 12 after the detection of the second document edge sensor. In addition, it is possible to prevent the document D from falling out of the nip portion of the third transport roller pair 32 and being unable to re-transport the document D by the third transport roller pair 32.

[Other Embodiments] In the above embodiment,
Although the U-turn path has been described as an example of the document conveyance path,
The present invention is not limited to this. For example, the same effects can be obtained even with a straight path.

Although the flapper has been described as an example of the transport path switching means, the present invention is not limited to this. For example, a mylar or the like is used to push the mylar away in the forward direction, and follow the mylar in the reverse direction. You may be made to guide.

In the above-described embodiment, the image reading unit in the facsimile apparatus is exemplified as the image reading apparatus. However, the present invention is not limited to this. For example, the image reading apparatus may be a scanner alone or a copier. The same effect can be obtained by applying the present invention to an image reading device or an image reading device in a multifunction device in which a printer function, a facsimile function, a copy function, and the like are appropriately combined.

[0066]

As described above, according to the present invention,
Since the transport speed V2 when the document is transported in the reverse direction is higher than the transport speed V1 when reading the image, the operation time when reading both sides of the document can be reduced, and the efficiency can be increased.

The distance l1 between the original detecting means provided upstream of the reading means and the pair of original conveying rollers constituting the original conveying means provided upstream of the original detecting means is determined by the end of the original. By setting the reverse transport distance V2 × t2 + l2 from when the document reaches the document detecting means to when the document is stopped, it is possible to prevent the document from falling out of the document transport roller pair and being unable to be transported again. .

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of an image reading unit according to a first embodiment of the present invention.

FIG. 2 is an external perspective view of a facsimile apparatus including an image reading unit to which the present invention has been applied.

FIG. 3 is a flowchart illustrating a flow of an operation in the image reading unit according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 13 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 14 is a schematic cross-sectional view illustrating a schematic configuration of an image reading unit according to a second embodiment of the present invention.

FIG. 15 is a flowchart illustrating a flow of an operation in the image reading unit according to the second embodiment of the present invention.

FIG. 16 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 17 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 18 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 19 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 20 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 21 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 22 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 23 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 24 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

FIG. 25 is a cross-sectional view illustrating a document conveying operation of the image reading unit according to the first embodiment of the present invention.

[Explanation of symbols]

 D: Document V1: Document transport speed V2: Reverse transport speed 11: Distance 12: Distance t2: Time 1: Device body 2: Image reading unit 3: Image forming unit 11: Document mounting table 12: Document detection sensor 13: Pickup Roller 14… Separation roller 15… Reverse roller 16… Document feed sensor 17… First transport roller pair 18… U-turn path 19… Second transport roller pair 20… Document edge sensor 21… Surface reading section 22… Reverse path 23… Back side reading Unit 24… Discharge roller pair 25… Document discharge tray 26… Drive motor 27… Electromagnetic clutch 31… First document edge sensor 32… Third transfer roller pair 33… Transport path switching flapper 34… Reverse path 35… Second document Edge sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/00 108 H04N 1/00 108M 1/12 Z F-term (Reference) 2H076 BA14 BA24 BA35 BA36 BA58 BA68 BB02 BB05 BB08 5B047 AA01 BA01 BC18 CA08 CB06 5C062 AA02 AA05 AB32 AB46 AC02 AC11 AC12 AC15 AC66 AC71 BA04 5C072 AA01 BA03 NA01 NA05 NA07 WA02 XA01

Claims (6)

[Claims] A document feeder for feeding a document in a forward / reverse direction; a document feeder for guiding the document fed by the document feeder; and a document feeder provided in the document feeder. A first reading unit that reads image information, and a second reading unit that is provided in the document conveyance path and reads image information on the other surface of the document, while the document conveyance unit conveys the document in a forward direction. Reading the image information on one side by the first reading means,
After the reading of the image on one side is completed, the original is transported in the reverse direction by the original transporting means, and then, while the original is transported in the forward direction again by the original transporting means, the image information of the other side is read by the second reading means. In the image reading apparatus for reading the document, when the document conveying unit sets the conveying speed of the document when reading the image information to V1 and the conveying speed when conveying the document in the reverse direction to V2, the relationship between the two conveying speeds is as follows: V1 ≦
V2. 2. A document conveying means capable of conveying a document in a forward / reverse direction, a document conveying path for guiding a document conveyed by the document conveying means, and a document conveying path provided in the document conveying path. A first reading unit that reads image information, and a second reading unit that is provided in the document conveyance path and reads image information on the other surface of the document, while the document conveyance unit conveys the document in a forward direction. Reading the image information on one side by the first reading means,
After the reading of the image on one side is completed, the original is transported in the reverse direction by the original transporting means, and then, while the original is transported in the forward direction again by the original transporting means, the image information of the other side is read by the second reading means. In the image reading apparatus for reading the document, a document detecting means for detecting the document is disposed on the upstream side of at least one of the reading means with reference to the transport direction in the forward transport of the document, and the upstream side of the document detecting means. A document conveying roller pair that constitutes the document conveying means, and a conveying speed when the document is conveyed in the reverse direction is set to V2. Further, when the document is conveyed in the reverse direction at the conveying speed V2, the document is detected. The time required from when the document edge reaches the means to when the document edge is detected is t2, the transport distance required to stop the document from the transport speed V2 is l2, and the document transport is performed. Wherein the distance between the document feed roller and the document detecting means is l1> V2 × t2 + l2, where the distance between the roller pair and the document detecting means is l1. apparatus. 3. The image reading apparatus according to claim 1, further comprising: a document feeder configured to feed the documents one by one toward the document feeder. 3. A bypass means for preventing a document conveyed in the reverse direction by said document conveying means from returning to said document feeding means is provided upstream of said reading means. Image reading device. 4. The branch transport path provided at an upstream side of at least one of the reading means and guiding a document branched from the document transport path and transported in a reverse direction by the document transport means. The image reading device according to claim 3, wherein: 5. A branch conveyance path provided on an upstream side of at least one of the reading means, for guiding a document branched from the document conveyance path and conveyed in a reverse direction by the document conveyance means. The image reading apparatus according to claim 3, further comprising a conveyance path switching unit that switches a conveyance path at a branch portion between the document conveyance path and the branch conveyance path. 6. The apparatus according to claim 1, wherein the transport speed V2 for transporting the document in the reverse direction is a maximum transport speed of a driving unit that rotationally drives the document transport unit.
The image reading device according to claim 5.