JPH11308404A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the accurate image reader of high read accuracy capable of stabilizing the carrying state of an original before and after a read position and suppressing the change of the feed speed of the original at the read position. SOLUTION: This image reader is provided with a main body side guide 100c for correcting the original carrying state after an original rear end is passed through a carrying roller pair 8 and 8a in the middle of the read position and an intermediate carrying roller pair 11 and 11a and is provided with a projected part formed higher than the original carrying surface of the downstream on the main body side guide 100c. Or, a guide roller is provided instead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image reading apparatus such as a scanner, a copying machine, and a facsimile.

[0002]

2. Description of the Related Art In a conventional image reading apparatus, as shown in FIG. 2, the vicinity of a reading position is reduced in order to reduce the size of the entire apparatus, and a conveying roller for conveying a separated document to the reading position. 8 and a first transport path R ₁ between the intermediate document transport roller 11 for transporting the read document to the sheet discharge unit.
It is configured to have a curved portion. In addition, on the first transport path R ₁ , AD
The F side guide 100a, the reading guide member 102, the main body side guide 100b, and the like are arranged at appropriate intervals. In addition,
The document feed speed is usually set so that the feed speed of the intermediate transport roller 11 downstream of the reading position is slightly higher than the feed speed of the transport roller 8 upstream of the reading position. . This is to prevent the original from bending at the reading position, because if the original is bent at the reading position, the feeding speed of the original at the reading position changes and accurate reading cannot be performed. Although it is conceivable that the upstream and downstream of the reading position have the same feed speed, the downstream side may be slowed down due to variations in the diameter of the conveying roller and the like. Therefore, the downstream side is usually set to be fast.
In such an apparatus, while the conveyance roller 8 and the intermediate conveyance roller 11 are nipping the document, the document 1 is stretched as shown by a dashed line in FIG. There is no expansion or contraction of the information. Thereafter, when the trailing end of the document passes through the transport roller 8, the transport state of the document changes from a state in which the document 1 is stretched to a state in which the document is bent as shown by a broken line in the figure. For this reason, at the reading position on the contact glass 101, the document feed speed changes due to the bending of the document, and the read image information partially expands and contracts.

[0003] Incidentally, as a device related to this kind, Japanese Patent Application Laid-Open No. 7-64359 and Japanese Patent Application Laid-Open No.
No. 7 publication.

[0004]

In the above-mentioned prior art, the conveying means (conveying roller 8) in which the rear end of the document is located upstream of the reading position.
When the document passes through, the document transport state changes from a stretched state to a bent state, so that the document feed speed changes at the reading position, resulting in partial expansion and contraction of the read image information. There's a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to improve such a problem, stabilize the conveyance state of a document before and after a reading position, suppress a change in the document feed speed at the reading position, and provide an accurate reading. An object of the present invention is to provide a highly accurate image reading apparatus.

[0006]

In order to achieve the above object, the present invention is arranged upstream of a document reading position,
An upstream conveying means for nipping and conveying the original; a downstream conveying means for nipping and conveying the original disposed downstream of the reading position; and an intermediate position between the reading position and the downstream conveying means for conveying the original. And a correction means for correcting the conveyance state of the document by projecting a part thereof, wherein the conveyance path in which the upstream conveyance means, the correction means, and the downstream conveyance means are arranged has a curved portion. It is characterized by having been done.

[0007] The correcting means has a convex portion formed higher than the document conveying surface downstream of the correcting means.
The convex portion may be configured to correct the conveyance state of the document after the rear end of the document has passed through the upstream conveyance unit. Further, the correcting means is a guide roller arranged so as to be in contact with the conveyed document at a position higher than the document conveying surface downstream of the correcting means, wherein the guide roller has a rear end of the document on the upstream conveying means. Is configured to correct the conveyance state of the document after passing through.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an image reading apparatus according to a first embodiment of the present invention. An automatic document feeder (ADF) 200 is mounted on an apparatus main body 100. The first document feed path R ₁ of the automatic document feeder 200 has a curved portion. On the first sheet feed path R ₁ , an image surface of the document 1 is located upstream of a reading position when the reading unit 10 reads the image. ,
A conveying roller pair (conveying roller 8 and conveying driven roller 8a = upstream conveying means) for pinching and conveying the document 1 to the reading position is arranged. A reading guide member 102 is disposed near the reading position, and the reading guide member 102
Downstream, a pair of intermediate conveyance rollers (an intermediate conveyance roller 11 and an intermediate conveyance driven roller 11
a = downstream conveying means).

Further, a reading guide member 1 near the reading position.
02 and the intermediate conveyance roller pair 11, 11a, the first
Body side guide 100c partially on the conveyance path R ₁ to correct the conveying state of the document 1 projects (= correcting means) is disposed. That is, as shown in FIG.
0c has a leading end portion (= convex portion) formed higher than the document transport surface (the guide surface of the ADF side guide 100a) downstream thereof, and the leading end portion has a reading guide member facing the contact glass 101. 102 and intermediate transport roller pair 1
Near the reading position so as to be in contact with the tangent line with the pair of transport rollers 8, 8a and the pair of intermediate transport rollers 11, 11a. Is provided between the reading guide member 102 and the pair of intermediate transport rollers 11 and 11a. With this configuration, while the pair of transport rollers 8, 8a and the intermediate transport rollers 11, 11a hold the document 1, the document 1 is stretched upstream and downstream of the reading position as indicated by a dashed line. It is in. Further, when the trailing end of the document passes through the pair of conveying rollers 8 and 8a, a portion upstream of the reading position of the document 1 changes to a bent state as shown by a dotted line.
On the other hand, the portion downstream of the reading position of the original 1 is lifted by the leading end of the main body side guide 100c, and thus the transport state before the rear end of the original passes through the transport roller pair 8, 8a (the state where the original is stretched without bending). Keep).

When the main body side guide 100c is formed, the leading end thereof may simply be raised so as to be in contact with the tangent line. However, the curvature of the conveying path itself becomes small, which is unsuitable for conveying thick paper originals. More preferably, it is more preferable to arrange the intermediate transport roller pair 11, 11a lower,
The guide member at the lower part of the conveyance path (the end of the main body side guide 100c) is formed so as to contact the document surface. In order to reduce the load of transporting the document by the main body side guide 100c, the height of the leading end may be set to be about 0.5 to 1 mm lower than the height at which the leading end contacts the document surface.

Further, instead of the main body side guide 100c,
A guide roller 103 as shown in FIG. 4 may be provided. The guide roller 103 is located on the downstream side of the document transport surface (ADF).
(The guide surface of the side guide 100a) so as to be in contact with the conveyed document at a higher position, that is, so as to be in contact with the tangent line. In addition, the transport load of the document 1 can be reduced as compared with the embodiment.

In this embodiment, the sheet feeding / separating unit for sequentially conveying the originals 1 stacked and placed on the original table 2 one by one from the uppermost one is provided on the original feeding side on the original table 2. A bottom plate 4 for supporting and raising the sheet 1 to a position in contact with the call roller 5, a sheet feeding member 6 that rotates in the sheet feeding direction and takes in the original 1 called by the call roller 5, and a direction opposite to the sheet feeding direction , And a separation member 7 for separating only the uppermost one of the fed documents 1. The sheet feeding member 6 and the separating member 7 are driven by a drive motor (not shown) (for example, a stepping motor).

A transport unit for transporting the original 1 transported from the paper feed / separation unit to a reading position on the contact glass 101 is provided by a pair of transport rollers 8, 8a, intermediate transport rollers 11, 11a, and the like. The rollers are driven by a drive motor (not shown) (for example, a stepping motor). Since the transport speed of the intermediate transport roller 11 is set to be slightly faster (for example, about 1%) than the transport speed of the transport roller 8, the transport roller pair 8,
The document 1 nipped and conveyed at 8a moves on the contact glass 101 and is scooped by the main body side guide 100c, and then the document 1 is nipped by the pair of conveying rollers 8, 8a and the intermediate conveying rollers 11, 11a. While the document 1 is stretched, the document 1 is not in contact with the contact glass 101,
In addition, the state where the contact surface with the reading guide member 102 is small is maintained. Further, even after the trailing edge of the document has passed the pair of conveying rollers 8 and 8a, the document 1 is kept stretched by the main body side guide 100c as described above, and passes through the reading position.

A reading unit 1 for reading an image surface of the original 1
Reference numeral 0 denotes an unillustrated exposure lamp, a first mirror, an optical system such as a lens, and the like, and is provided in the apparatus main body 100 below the contact glass 101. When reading an image, the exposure lamp and the first mirror are moved in the horizontal direction in FIG. 1 below the contact glass 101 or stopped below the reading position, and light is irradiated on the image surface by the exposure lamp. After that, the reflected light is imaged on a photosensitive drum (not shown) via the first mirror and the optical system, and toner or the like is attached to the electrostatic latent image formed on the photosensitive drum to form a recording paper. The image is transferred or the reflected light is imaged on an image sensor such as a CCD via a first mirror and an optical system. The image sensor converts a light signal into an electric signal, and uses various image forming means. To transfer the image to recording paper.

Further, the original 1 after the reading is transferred to the discharge tray 15.
Alternatively, a paper discharge unit for discharging to the intermediate tray 17 includes a paper discharge sensor (for example, an optical reflective sensor) 13 for detecting the original 1 conveyed through the intermediate conveyance roller pair 11 and 11a, A switching claw 14 for changing the transport direction at the time of reversing, a reversing sensor (for example, an optical reflective sensor) 18 for obtaining detection information as a trigger for controlling the timing of changing the transport direction, and a drive motor (not shown) Driven paper ejection roller 12 and reversing roller 1
6, etc.

The ADF 200 of the present embodiment is connected to a main body 100 of the apparatus by a connecting member such as a hinge (not shown).
And can be opened and closed in the direction of arrow C.
Next, the sheet feeding / separating operation in the present embodiment will be described.
In the present embodiment, the originals 1 stacked on the original table 2 with the first image surface facing upward are the main body 100 of the apparatus.
When a start signal is sent to the ADF 200 by pressing a start button (not shown) in the operation unit,
Paper is fed one by one in order from the top. The operation procedure will be described below. When the originals 1 are stacked and placed on the original table 2, the leading end of the originals is positioned by abutting the paper feed guide plate 3. When the original 1 is set in this manner, the bottom plate 4 is raised by a solenoid (not shown) in the direction of arrow A in response to the start signal, and pushes the original 1 up to a position where the original 1 comes into contact with the call roller 5. The original 1 pressurized by the call roller 5 is fed by the call roller 5 rotating in the sheet feeding direction, by the sheet feeding member 6 and the separation member 7.
And is separated one by one from the top. The bottom plate 4 that has risen as described above falls after a fixed time from the start of sheet feeding or after the leading edge of the document is detected by the registration sensor 9. That is, when the bottom plate 4 is lowered, the pressure between the bottom plate 4 and the call roller 5 applied to the original 1 is released, and the second image surface of the original 1 being conveyed is rubbed against the first image surface of the next original. This is to reduce time. When the bottom plate 4 is lowered after a predetermined time from the start of sheet feeding, it is desirable to set the time as short as possible in order to reduce dirt due to rubbing. Note that manuscript 1
Is only a single-sided image (first image side), there is no second image side, so there is no need to lower the bottom plate 4. Whether to perform single-sided reading or double-sided reading is set in advance by the user arbitrarily selecting the single-sided / double-sided mode using the operation unit.

[0017] Thus the document 1 which is separated one by one is conveyed to the first conveyance path R ₁ to conveying roller pairs 8,8a are arranged. A registration sensor 9 disposed in the vicinity of the conveying roller pair 8, 8a detects the leading edge of the document and reads the document.
The timing of the passage of the leading edge of the document to the start of image reading is adjusted. If the registration sensor 9 does not detect the leading edge of the document 1 even after a certain period of time after the document 1 is separated and conveyed, it is determined that a jam has occurred.

Further, a single-sided / double-sided mode in the operation unit is provided.
The reading operation starts according to the setting of the mode. First in single-sided mode
When reading only one image surface, the original 1 is
The image information of the first image plane was read as described above.
Then, a pair of intermediate transport rollers 11 and 11a, a discharge roller 12,
Transport path R in which the paper discharge driven roller 12a is disposed
_TwoAnd is discharged to the paper discharge tray 15. At this time, constant
Even after a lapse of time, the leading edge of the original is detected by the paper ejection sensor 13.
If no document is found, or after the leading edge of the document is detected,
The trailing edge of the document is not detected by the paper ejection sensor 13 even after the elapse
In this case, the jam is determined. The switching claw 14 is in the B position.
(Home position), the discharge rollers 12 and
The document 1 nipped and conveyed by the driven lower roller 12a is discharged.
It is guided to the paper tray 15 side.

On the other hand, the first image plane and the second
When reading an image plane, after the document 1 is read a first image plane, as described above, through the second conveyance path R _2, third conveyance reverse roller 16, and the reversing driven roller 16a is disposed It is discharged to the intermediate tray 17 through the road R _3.
At this time, whether the leading edge of the document is detected by the paper discharge sensor 13
Alternatively, at a predetermined timing after the registration sensor 9 detects the document 1, the switching claw 14 is lowered from the position B (home position) to the position B ′ by a solenoid (not shown), and the paper discharge roller 12 and the paper discharge Lower driven roller 12
The document 1 pinched and conveyed at a is guided to the intermediate tray 17 side. Incidentally, when the document 1 through the third conveyance path R ₃ even when predetermined time has elapsed not detected reverse sensor 18 is determined to be jammed.

The switching claw 14, which has been lowered to the position B ', is moved for a certain period of time after the leading edge of the document has passed through the paper discharge sensor 13 (when the trailing edge of the document has passed through the paper discharge roller pair 12, 12a, the switching claw 14).
After the elapse of the time until the pressure reaches), the solenoid is released to return to the position B (home position). After the return of the switching claw 14, the reversing roller 16 rotates in the reverse direction, and the leading end of the document enters the nip portion of the discharge roller 12 and the driven upper roller 12b. At this time, the discharge rollers 12
Is stopped, and a skew (original skew feed) butting correction is performed. After the abutment correction end, the document 1 is conveyed to the reading position through the fourth conveyance path R ₄ and the first transport path R _1,
The reading unit 10 reads the second image surface.

After the second image surface is read in this way, the switching claw 14 is moved to the position B 'in order to arrange the pages of the original 1 (so that the first image surface is stacked downward). Thus, the document 1 after reading through the second conveyance path R ₂ passes through the third conveyance path R _3, the second image plane is temporarily held in the intermediate tray 17 downward. After this, the switching claw 1
4 returns to the B position (home position), and the document 1 once held in the intermediate tray 17 is moved to the fourth transport path R ₄ ,
The sheet passes through the first transport path R ₁ and the second transport path R _2, and is discharged to the discharge tray 15 with the first image surface facing downward.

Thereafter, the feeding operation of the next original by the call roller 5 is started by the start signal from the operation unit. When the bottom plate 4 is raised by the start signal, the bottom plate 4 is raised to a predetermined position. Is added to the paper feed time, the bottom plate 4 is raised in advance before the start signal is received in preparation for feeding the next document. That is, when the discharge operation of the current document, the document leading end passes through the fourth conveyance path R _4, the leading edge of the document is detected, raising the bottom plate 4 by the registration sensor 9. The timing of raising the bottom plate 4 may be raised between the time when the rear end of the original passes through the page roller 5 and the start of feeding the next original. Is set so that the bottom plate 5 rises at the time.

[0023]

As described above, according to the present invention,
Between the reading position and the downstream transport unit (= intermediate transport roller pair), the rear end of the document is the upstream transport unit (= transport roller pair).
A correction means (= body side guide) for correcting the state of document transport after passing the document is provided, and the correction means has a convex portion formed higher than the document transport surface on the downstream side, so that the leading edge of the document is moved from the reading position. The conveyance state of the document while being conveyed to the downstream conveyance means is conveyed in substantially the same state as the document conveyance state stretched by the upstream and downstream conveyance means, and a change in the document feed speed at the reading position is suppressed. Thus, accurate image information can be read.

Further, the correcting means is constituted by a guide roller arranged so as to be in contact with the original at a position higher than the original conveying surface on the downstream side thereof, so that a conveying load is applied to the original in addition to the above-mentioned effect. The effect that there is no is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an image reading device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration near a reading unit in a conventional image reading apparatus.

FIG. 3 is a diagram illustrating a configuration near a reading unit in the image reading apparatus according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration near a reading unit in an image reading apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original 8 Conveyance roller 8a Conveyance driven roller 10 Reading part 11 Intermediate conveyance roller 11a Intermediate conveyance driven roller 102 Reading guide member 101 Contact glass 100a ADF side guide 100c Body side guide

Continued on the front page (72) Inventor Minoru Itoigawa Ricoh Elemex Co., Ltd. 2-2-1-13 Nishiki, Naka-ku, Nagoya City, Aichi Prefecture

Claims (3)

[Claims] 1. An image forming apparatus, which is disposed upstream of a document reading position,
An upstream conveying means for nipping and conveying the original; a downstream conveying means for nipping and conveying the original disposed downstream of the reading position; and an intermediate position between the reading position and the downstream conveying means for conveying the original. And a correction means for correcting the conveyance state of the document by projecting a part thereof, wherein the conveyance path in which the upstream conveyance means, the correction means, and the downstream conveyance means are arranged has a curved portion. An image reading apparatus, comprising: 2. The correcting device according to claim 1, wherein the correcting device has a convex portion formed higher than a document conveying surface downstream of the correcting device, and the rear end of the document has passed through the upstream conveying device at the convex portion. 2. The image reading apparatus according to claim 1, wherein the image reading apparatus is configured to correct a conveyance state of a subsequent document. 3. The correcting means is a guide roller arranged so as to be in contact with a conveyed document at a position higher than a document conveying surface downstream of the correcting means. 2. The image reading apparatus according to claim 1, wherein the image reading apparatus is configured to correct a conveyance state of the document after passing through the side conveyance unit.