JP2000059567A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain reduction of throughput of original reading, reduction of noise, saving of a device installing space, improvement of durability and the like. SOLUTION: This device has a switching circuit 33 for switching an input origin of image information to an image processing circuit 32 to two tightly contact type image sensors 17 and 21, a driving control mechanism 36 for rotating/stopping a second carrier roller pair disposed on an upstream side of a first carrier roller/the second tightly contact type image sensor 21 pair disposed on an downstream side of the first tightly contact type image sensor 17, a cover opening/closing mechanism 37 for releasing a cover composing the original carrying path in accordance with the length in a carrying direction of the original, and the like. Then, if the leading edge reaches the second image sensor 21 before the trailing edge of the original (D) reaches the first image sensor 17, the release of the original carrying path is performed by the release of the cover by the cover opening/closing mechanism 37 and, if this trailing edge reaches the first image sensor 17 before the leading edge of the reaches the second image sensor 21, the release of the original carrying path is not performed by releasing the cover by the cover opening/closing mechanism 37.

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.

For example, JP-A-60-96069 and JP-A-60-96069
-126964, JP-A-62-51367, JP-A-62-258
552, JP-A-1-180576, JP-A-2-21564, JP-A-3-240361, and JP-A-3-256447 (hereinafter referred to as "prior art 1"). As described above, there is an image reading apparatus that simultaneously reads image information on both sides of a document by one sheet passing by two reading units facing each other via a document conveyance path.

Further, as disclosed in Japanese Patent Application Laid-Open No. 1-194658 (hereinafter referred to as "prior art 2"), two reading means facing each other via a document conveyance path can be used for one pass of paper. At the same time, read the image information on both sides of the original,
There is an image reading device that can select whether to set a page.

Further, as disclosed in Japanese Patent Application Laid-Open No. 1-126870 (hereinafter referred to as "Prior Art 3"), two original reading means which switch back an original and which oppose each other with an original contact roller therebetween. There is an image reading apparatus that reads image information of a document one by one.

Further, as disclosed in Japanese Patent Application Laid-Open No. 3-265355 (hereinafter referred to as "Prior Art 4"), reading means are provided above and below a U-turn path, respectively, so that an original can be scanned by the U-turn path. 2. Description of the Related Art There is an image reading apparatus in which image information on the front and back of a document is separately read by each of the reading means in a loop.

[0007]

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

In the above-mentioned prior art 1 and prior art 2, since two reading means are operated at the same time, there are (two) image processing means for processing image information read by the reading means.
Required and costly. 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 units in advance, and a single-sided reading function requires two image processing units in advance. The cost merit of a device with functions is unlikely to appear.

In the prior art 3, the document returned by switchback is read from the rear end, and
When transmitting as an AX 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.

[0010] Furthermore, when the leading edge of the original to be switched back protrudes most out of the apparatus, only the rear end of the original is pinched and held by the rollers. It is in a state of jumping out of
Skew is likely to occur, which may cause a conveyance failure.
In order to prevent this, it is necessary to configure a large document conveying path that contains the switched back document, and the apparatus becomes large.

In the prior art 4, if the apparatus is configured to read a large document such as an A3 size document, the document conveying path for forming a loop becomes large, and the apparatus becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the document reading throughput, reduce noise, reduce the space required for the apparatus, and improve the durability.

[0013]

A typical configuration of the present invention for achieving the above object is a first reading means for reading image information on one side of a document, and a first reading means for reading image information on the other side of the document. A second reading unit for reading, an image processing unit for processing image information read by the first reading unit and the second reading unit, and an input source of image information to the image processing unit, the first reading unit or the Document transport including switching means for switching to second reading means, at least a first transport rotating body disposed downstream of the first reading means, and a second transport rotating body disposed upstream of the second reading means. Means, a drive control means for rotating / stopping the second transport rotator, and a document transport path between the first transport rotator and the second transport rotator according to the length of the document in the transport direction. Transport path opening means for expanding the space, If the leading end of the document reaches the second reading means before the trailing end of the document reaches the first reading means, the document conveying path is opened by the conveying path opening means, and the leading end of the document is If the trailing end of the document reaches the first reading means before reaching the second reading means, the document path is not opened by the transfer path opening means.

Further, the transport path opening means opens the openable cover constituting the document transport path to reduce the slack of the document generated between the first transport rotating body and the second transport rotating body. It is characterized in that it is configured to be open to the outside.

According to the above arrangement, when the leading end of the document reaches the second reading means before the trailing end of the document reaches the first reading means, that is, between the first reading means and the second reading means. If the length of the document in the transport direction is longer than the length of the document transport path, the document transport path is opened, and the deflection of the document generated during transport is released outside the apparatus. Reading is performed.

On the other hand, when the trailing edge of the document reaches the first reading means before the leading edge of the document reaches the second reading means,
That is, if the length of the document in the transport direction of the document is shorter than the length of the document transport path between the first reading unit and the second reading unit in the transport direction,
Since it is not necessary to release the deflection of the document occurring during the transport to the outside of the apparatus, the document transport path is not opened, thereby reducing the throughput of reading the document, reducing noise, and reducing the space required for the apparatus. And the durability can be improved.

[0017]

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 12,
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. 1 is an external perspective view of a facsimile machine. In FIG. 1, 1 is an apparatus main body, 2 is an image reading unit according to the present invention, 3 is a recording unit composed of a laser beam printer, 4 is a document table configured to be able to stack a plurality of documents D, Reference numeral 5 denotes a document discharge tray.

FIG. 2 is a schematic sectional view showing a schematic configuration of an image reading section in the facsimile apparatus. In FIG.
Reference numeral 11 denotes a document presence / absence detection sensor for detecting whether or not the document D is set on the document table 4, reference numeral 12 denotes a pickup roller for feeding the set document D into the image reading unit 2, and reference numerals 13 and 14 cooperate. A reversing roller and a separation roller for separating a plurality of documents D one by one; a feed roller pair 15 for feeding the separated document D; and a first roller 16 for detecting the leading and trailing edges of the document. A document edge detecting sensor, 17 is a first contact type image sensor (first reading means) for reading image information on the surface of the document D, and 18 and 19 are first transport roller pairs (first transport rotation) for nipping and transporting the document D. Body) and a pair of second transport rollers (second transport rotator), 20 is a second original edge detection sensor for detecting the leading and trailing edges of the original, and 21 is the second which reads image information on the back surface of the original D. Contact type image sensor (second reading means),
Reference numeral 22 denotes a discharge roller pair for discharging the document D onto the document discharge tray 5, reference numeral 23 denotes a document transport path, and reference numeral 24 denotes an openable / closable cover constituting a U-turn path portion of the document transport path 23.

FIG. 3 is a block diagram showing an example of the control configuration. In FIG. 3, reference numeral 31 denotes a control circuit for controlling the image reading unit 2; 32, an image processing circuit (image processing circuit) for processing image information of the original D read by the first contact image sensor 17 and the second contact image sensor 21; A switching circuit (switching means) for switching the input source of image information to the image processing circuit 32 to the first contact image sensor 17 or the second contact image sensor 21; A driving motor 36 for rotating the feed roller pair 15, the first transport roller pair 18, the second transport roller pair 19, and the paper discharge roller pair 22 constitutes a component, and rotates / stops the second transport roller pair 19. A drive control mechanism (drive control means) constituted by a clutch, a solenoid, and the like, and a cover opening / closing mechanism (transport path opening means) constituted by a motor, a solenoid, a cam mechanism, and the like for opening and closing the cover 24. . Reference numeral 16 denotes the above-described first document end detection sensor, and reference numeral 20 denotes the above-described second document end detection sensor.

(Explanation of Operation of Apparatus) Next, the operation of the image reading section 2 will be described based on the flowcharts shown in FIGS. 4 and 5 with reference to FIGS.

The user sets the original D on the original placing table 4 with its front side up (S1). Then, the document D is detected by the document presence detection sensor 11 (S2).

If the input source of the image information to the image processing circuit 32 is not the first contact type image sensor 17, the switching circuit 33 switches to the first contact type image sensor 17 (S3). Then, the user sets predetermined reading conditions (resolution, density, etc.) and starts reading (S
4).

The documents D stacked on the document table 4 are picked up and conveyed by the pickup roller 12, and are separated and fed one by one by the reverse rotation roller 13 and the separation roller 14 constituting the document separation means (S5).

The separated document D reaches the feed roller pair 15, and when the leading edge of the document D is detected by the first document edge detecting sensor 16 (S6), the reading start position of the document D is set to the first contact type image sensor. After measuring the timing until the reading reference position 17 is reached, reading of the image information on the front surface by the first contact type image sensor 17 is started (S7).

The original D reaches the first conveying roller pair 18,
The image information is sent to the U-turn path portion of the document conveying path 23 and is further conveyed in the direction of the second conveying roller pair 19, and the reading of the image information is continued. During this reading, the first document edge detection sensor 16
To monitor whether the trailing edge of the document D is detected.

(Operation when the trailing edge of the original is not detected by the first edge detecting sensor in S8) First, before the trailing edge of the original D is detected by the first edge detecting sensor 16, The operation when the trailing edge of the document D is detected by the second document edge detection sensor 20 (S8, S9) will be described.

After the document D reaches the second transport roller pair 19, the leading edge of the document D is detected by the second document edge detecting sensor 20 (S9, see FIG. 6). The rotation of the transport roller pair 19 is stopped (S10), and the cover 24 is opened by the cover opening / closing mechanism 37 (S11, see FIG. 7). That is, the space of the U-turn path portion of the document conveying path 23 between the first conveying roller pair 18 and the second conveying roller pair 19 is widened.

At this time, the vicinity of the leading end of the original D is stopped by the second pair of transport rollers 19, but the portion upstream of the original D is continuously transported by the first pair of transport rollers 18 and the like. The document D sags between the roller pair 18 and the second transport roller pair 19. However, as described above, since the cover 24 is opened and the slack of the document D is configured to swell outside the image reading unit 2 as shown in FIG. 8, the document D does not jam. .

Thereafter, when the trailing edge of the document D is detected by the first document edge detection sensor 16 (S12), the reading end position of the document D is maintained until the reading end position of the first contact image sensor 17 reaches the reading reference position. After measuring the timing, the reading of the image information of the front surface by the first contact type image sensor 17 is completed (S13).

The switching circuit 33 switches the input source of the image information to the image processing circuit 32 to the second contact type image sensor 21 (S14), and the second drive control mechanism 36 restarts the rotation of the second conveying roller pair 19. Is performed (S15).

After measuring the timing until the reading start position of the document D reaches the reading reference position of the second contact image sensor 21, reading of the back side image information by the second contact image sensor 21 is started. (S16, see FIG. 9).

When the rear end of the original is detected by the second original end detecting sensor 20 (S17), the cover 24 is closed by the cover opening / closing mechanism 37 (S18, see FIG. 10).

At the same time, the timing until the reading end position of the document D reaches the reading reference position of the second close contact type image sensor 21 is measured, and then the reading of the back side image information by the second close contact type image sensor 21 ends. (S19).

Thereafter, the document D is discharged onto the document discharge tray 5 by the discharge roller pair 22 (S20).

The above steps S5 to S20 are repeated until the document D on the document table 4 is exhausted. When the absence of the document is detected by the document presence / absence detection sensor 11, all reading operations are completed.

(Operation when the trailing edge of the original is detected by the first edge detecting sensor in S8) On the other hand, before the leading edge of the original D is detected by the second edge detecting sensor 20, The operation when the leading edge of the document D is detected by the document edge detection sensor 20 (S8) will be described.

When the trailing edge of the document D is detected by the first document edge detection sensor 16 (S8, see FIG. 11), the reading end position of the document D reaches the reading reference position of the first contact image sensor 17. After the timing up to, the reading of the image information on the front surface by the first contact image sensor 17 is terminated (S21).

The input source of the image information to the image processing circuit 32 is switched to the second contact type image sensor 21 by the switching circuit 33 (S22).

Thereafter, the original D is transferred to the second transport roller pair 19.
And the leading edge is detected by the second document edge detecting sensor 20 (S23, see FIG. 12), the timing until the reading start position of the document D reaches the reading reference position of the second contact image sensor 21 The second contact image sensor
The reading of the image information on the back side by 21 is started (S2
Four).

When the trailing end of the original is detected by the second original end detecting sensor 20 (S25), the timing is measured until the reading end position of the original D reaches the reading reference position of the second contact image sensor 21. After the second contact type image sensor 21
The reading of the image information on the back side is terminated (S19).

Thereafter, the document D is discharged onto the document discharge tray 5 by the discharge roller pair 22 (S20).

The steps S5 to S20 are repeated until the document D on the document table 4 is exhausted. When the absence of the document is detected by the document presence / absence detection sensor 11, all reading operations are completed.

As described above, when the trailing edge of the document D is detected in S8, the cover 24 is opened by the cover opening / closing mechanism 37 (S8).
11), driving of the second conveying roller pair 19 is stopped (S10), re-driving of the second conveying roller pair 19 (S15), and the cover 24 is closed (S10).
18) Steps can be omitted.

In this embodiment, the length of the document transport path between the first document edge detection sensor 16 and the second document edge detection sensor is set to the A4 horizontal transport which is a document size normally used by the user. Approximately 210mm (210mm (A4 horizontal length) +
The cover 24 is not opened when the user sets an A4 size document that is normally used horizontally on the side.

The value of (+ α) is set to a length in consideration of the detection error of the sensor, and is preferably set to a value as small as possible from the viewpoint of miniaturization of the apparatus and cost reduction. In this embodiment, (α = 10 mm) is set.

When a B4 or A3 size original is used, the second original end detection sensor 20 detects the leading end of the original D before the first original end detection sensor 16 detects the rear end of the original D. Therefore, the deflection of the document D that occurs during the conveyance of the document when the cover 24 is opened is absorbed, and good duplex reading is possible.

As described above, according to the present embodiment, if the leading end of the document D reaches the second contact image sensor 21 before reaching the first contact image sensor 17, When the length of the document D in the transport direction of the U-turn path portion of the document transport path 23 between the first contact image sensor 17 and the second contact image sensor 21 is longer than the length of the document transport path 23, The U-turn path is opened, and the deflection of the document D generated during the conveyance is released to the outside of the apparatus, so that good reading is performed.

That is, in the case of a document which is not used frequently by the user and which is not frequently used (for example, when a document of B4 or A3 size is vertically conveyed), the U-turn path portion of the document conveying path 23 is opened. And good two-sided reading is possible.

On the other hand, when the leading end of the document D reaches the first contact image sensor 17 before reaching the second contact image sensor 21, that is, when the original D contacts the first contact image sensor 17, Document feed path between image sensors 21
When the length of the document D in the transport direction is shorter than the length of the U-turn path portion 23 in the transport direction, the document D does not bend as described above, so that it is not necessary to release the deflection of the document outside the apparatus. The U-turn path section of the document transport path is not opened. Thereby, the following effects can be obtained.

In the case where the length of the original is a frequently used original which is normally used by the user (for example, when the A4 size original is conveyed horizontally), the U-turn path of the original conveying path 23 must be opened. Since it is not performed, the throughput of reading the document can be reduced.

For a user who frequently uses a document having a length in which the U-turn path of the document conveying path 23 is not opened, the installation space can be reduced.

Further, there is an effect that noise due to the opening and closing operation is reduced, and durability and reliability are improved because the opening and closing operation is not performed when unnecessary.

Since operations such as stopping and re-driving the second conveying roller pair 19 are not performed, there are effects such as a reduction in document reading throughput, and an improvement in durability and reliability.

The two contact image sensors 17 and 21
Can be switched by the switching circuit 33 and the image information can be sent to one image processing circuit 32. Therefore, it is not necessary to have a plurality of image processing circuits, and the electric circuit board can be downsized.
Costs can be kept low.

When a device having only a single-sided reading function is used as a standard form and a double-sided reading function is optional,
It is possible to realize the standard mode and the optional expansion mode with one image processing circuit, and it is possible to reduce the cost as compared with a configuration having two image processing circuits.

Before the image information of the original D is read by the second contact image sensor 21, the leading end of the original D is stopped by the pair of second transport rollers 19, and the original transport path 23 is opened, so that the original D is Since the slack of the document D resulting from the conveyance of the rear end side can be tolerated and the image information on the rear end side of the document D can be read by the first contact image sensor 17 while the front end of the document D is stopped. , First contact type image sensor
The distance between the image sensor 17 and the second contact image sensor 21 can be reduced, and the size of the device can be reduced.

Further, the leading end of the document D is moved to the second conveying roller pair 19.
After holding the document, the document transport path 23 is opened, and the document transport path 23 can be closed immediately after the slack of the document D has been eliminated. In addition, transport stability can be improved.

Further, since image information can be read from the front end of the document D on both the front and back sides, there is no need for an image reversing means for reversing the read image information or a document reversing means for reversing the document upside down. Therefore, as compared with a device that requires a document reversing unit or the like, the document reading throughput is faster, the device cost can be reduced, and the device configuration can be simplified.

The size of the entire apparatus can be reduced by opening the document conveying path 23 to allow the slack of the original D to escape outside the apparatus.

[Other Embodiments] In the above embodiment,
Before the leading edge of the document reaches the second contact image sensor 21, the configuration using the document edge detection sensors 16 and 20 has been exemplified as a means for determining whether the trailing edge reaches the first contact image sensor. The present invention is not limited to this. For example, as means for detecting the length of the document in the transport direction, the user can specify the document length before transporting the document, or
The same effect can be obtained by detecting the length of the cover 24 when it is set above and determining whether to open or close the cover 24.

In the above-described embodiment, the length of the document transport path between the first document edge detection sensor 16 and the second document edge detection sensor is set to the width of the A4 size document normally used by the user. Although the configuration supposing the case where the sheet is set and transported is described as an example, the present invention is not limited to this. The length may be set to a frequently used length as needed.

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.

[0065]

As described above, according to the present invention,
If the leading end of the document reaches the second reading means before the trailing end of the document reaches the first reading means, that is, the length of the document conveying path between the first reading means and the second reading means in the conveying direction. In the case where the length of the document in the transport direction is longer than that, by opening the document transport path, the deflection of the document generated during transport is released to the outside of the apparatus, so that good reading is performed.

That is, in the case of an infrequently used document which is not normally used by the user (for example, when a B4 or A3 size document is vertically conveyed), the document conveyance path is opened, so that good duplex reading is performed. Is possible.

On the other hand, if the trailing edge of the document reaches the first reading means before the leading edge of the document reaches the second reading means,
That is, if the length of the document in the transport direction of the document is shorter than the length of the document transport path between the first reading unit and the second reading unit in the transport direction,
Since it is not necessary to release the deflection of the document generated during the transport to the outside of the apparatus, the following effects can be obtained by not opening the document transport path.

When the length of the original is a frequently used original which is usually used by the user (for example, when the A4 size original is conveyed horizontally), the original conveying path is not opened. The throughput of reading the document can be reduced.

Also, for a user who frequently uses a document having a length that does not open the document conveyance path, the installation space can be reduced.

Further, there is an effect that noise due to the opening / closing operation is reduced, and durability and reliability are improved because the opening / closing operation is not performed when unnecessary.

Since operations such as stopping and re-driving the second transport rotating body are not performed, there are effects such as a reduction in document reading throughput, and an improvement in durability and reliability.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a facsimile machine.

FIG. 2 is a schematic sectional view illustrating a schematic configuration of an image reading unit in the facsimile apparatus.

FIG. 3 is a block diagram showing an example of a control configuration in the image reading unit.

FIG. 4 is a flowchart showing a flow of an operation in the image reading unit.

FIG. 5 is a flowchart showing a flow of an operation in the image reading unit.

FIG. 6 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

FIG. 7 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

FIG. 8 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

FIG. 9 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

FIG. 10 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

FIG. 11 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

FIG. 12 is a cross-sectional view illustrating a document conveying operation of the image reading unit.

[Explanation of symbols]

 D: Document 1: Device body 2: Image reading unit 3: Recording unit 4: Document table 5: Document discharge tray 11: Document presence / absence detection sensor 12: Pickup roller 13: Reverse rotation roller 14: Separation roller 15: Feeding roller Pair 16: First document edge detection sensor 17: First contact image sensor 18: First transport roller pair 19: Second transport roller pair 20: Second document edge detection sensor 21: Second contact image sensor 22 … Discharge roller pair 23… Document feed path 24… Cover 31… Control circuit 32… Image processing circuit 33… Switching circuit 34… Drive motor 36… Drive control mechanism 37… Cover opening and closing mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/00 108 G06F 15/64 320J F-term (Reference) 3F101 FB02 FE02 FE17 LA02 LA05 LB02 3F102 AA02 AA10 AB01 BA12 BB13 CA02 CB01 EA03 EB01 EC01 EC04 5B047 AA01 AB01 BA01 BA07 BB02 CA09 CA11 CA21 CB06 CB09 CB23 CB25 5C062 AA05 AB17 AB22 AB30 AB46 AC04 AC11 AC15 AC66 AC68 AC71 AD02 AD06 AE15 BA04 5C07 A03 A03 NA03 A03 A03 XA01 XA05

Claims (2)

[Claims] A first reading unit for reading image information on one side of the original; a second reading unit for reading image information on the other side of the original; and reading by the first reading unit and the second reading unit. Image processing means for processing the image information, and switching means for switching the input source of the image information to the image processing means to the first reading means or the second reading means, at least downstream of the first reading means Document transporting means having a first transporting rotator disposed and a second transporting rotator disposed upstream of the second reading means, a drive control means for rotating / stopping the second transporting rotator, and a document Transport path opening means for enlarging the space in the document transport path between the first transport rotary body and the second transport rotary body according to the length in the transport direction of the document. Before reaching the reading means, the leading edge of the original When the document reaches the second reading means, the document conveying path is opened by the conveying path opening means, and the trailing end of the document reaches the first reading means before the leading end of the document reaches the second reading means. An image reading apparatus that does not open the document conveyance path by the conveyance path opening means. 2. The apparatus according to claim 2, wherein the opening of the openable cover constituting the original conveying path is used to reduce a slack of the original generated between the first conveying rotator and the second conveying rotator. 2. The image reading apparatus according to claim 1, wherein the image reading apparatus is configured to be opened outside the apparatus.