JP3471553B2 - Automatic document feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder mounted on an image reading device such as a copying machine, a facsimile device, a scanner device or the like, and more specifically, by a pair of feeding rollers provided on both sides of a reading position. The present invention relates to an automatic document feeder for feeding book documents.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus such as a copying machine, a facsimile apparatus, a scanner apparatus or the like, when a document is read, a sheet or book document is placed on a contact glass to scan an optical system. I am trying. Recently, in place of such a configuration, a so-called manuscript moving type device is widely used in which an optical system is fixed and a manuscript itself is moved to perform scanning. In this device, A0, A
It is particularly useful for an apparatus using a large-sized original such as one size, and a scanning mechanism for moving a heavy apparatus such as an optical system can be eliminated, so that the apparatus configuration can be simplified and downsized. It has the advantage that

Various types of documents having a thickness such as a book-type document have been developed with the above-mentioned structure. As a conventional automatic document feeder of this type,
JP-A-57-82867, JP-A-58-1378
57 and Japanese Patent Application Laid-Open No. 8-40597, which are shown in FIG. In FIG. 8, reference numeral 1 denotes a contact glass forming a reading position, and an image forming unit 2 for forming an image of an original read by an optical system such as a light source and a lens (not shown) is arranged below the contact glass 1. It is set up. Further, a first transport roller 3 is provided on the upstream side in the transport direction of the book document 5 with the contact glass 1 interposed therebetween, and a second transport roller 4 is provided on the downstream side in the transport direction. 2 The transport rollers 3 and 4 are adapted to transport the book document 5 inserted from the insertion port.

The first and second transport rollers 3 and 4 are provided with a side plate 6.
The side plate 6 is rotatably supported by a pair of links 8 on a cover 7 attached to the main body of the automatic document feeder.
It is configured to move up and down in parallel with the transport surface A via. A spring 9 is provided between the side plate 6 and the cover 7.
The spring 9 urges the first and second transport rollers 3 and 4 downward via the side plate 6. Further, a reflection plate 10 is provided on the lower surface of the side plate 6, and the reflection plate 10 has a function of reflecting the light emitted from the light source. Reference numeral 11 is an auxiliary first roller that comes into contact with the first conveyance roller 3 via the book original 5 and rotates together with the first conveyance roller 3, and reference numeral 12 indicates the second conveyance roller 4 via the book original 5. It is an auxiliary second roller that abuts and rotates together with the second transport roller 4.

In the device having such a structure,
When the book document 5 is inserted from the insertion opening, the driving of the first and second transport rollers 3 and 4 is started, and the book document 5 is nipped by the first transport roller 3 and the first auxiliary roller 11, and
The sheet is sandwiched by the second transport roller 4 and the second auxiliary roller 12 and transported. At this time, the first conveying roller 3 moves upward by the thickness of the book original 5 against the urging force of the spring 9, and in conjunction with this, the second conveying roller 4 moves upward together with the reflecting plate 10 by the same amount. Moving.

When the trailing edge of the book original 5 passes through the second conveying roller 4, the first and second conveying rollers 3 and 4 and the reflecting plate 10 are biased by the spring 9 and move downward in parallel to move to the original state. Return to. On the other hand, when the book document 5 enters the second transport roller 4, the book document 5 is transferred to the transport roller 4 by the book document 5.
If it enters in such a manner that it hits against, the transport will be disturbed at this moment. At this time, since the image of the original is being read through the contact glass 1, image deviation (jitter) will occur if this disturbance occurs.

According to the conventional configuration, the first and second transport rollers 3 and 4 can be raised in parallel with the transport surface A, so that the second transport roller 4 is moved to the book document 5 prior to the entry of the book document 5. The thickness can be increased by an amount corresponding to the above, and it is possible to alleviate the above-mentioned conveyance disorder and prevent the occurrence of image shift.

[0008]

However, in such a conventional automatic document feeder, the first feeding roller 3 and the second feeding roller 4 are arranged on the feeding surface A of the book original 5.
The book manuscript 5
Since the second conveying roller 4 is moved upward in conjunction with the first conveying roller 3 during the conveyance of the sheet, the impact when the leading edge of the book document 5 abuts against the second conveying roller 4 is sufficiently reduced. Could not be prevented, and reading failure such as jitter could not be prevented.

On the other hand, in order to sufficiently reduce the impact, the first and second conveying rollers 3 and 4 are not provided in parallel with the conveying surface A, but the second conveying roller 4 is set to be more than the first conveying roller 3. However, with such a configuration, the conveyance force becomes insufficient after the trailing edge of the document passes through the first conveyance roller 3 to cause conveyance failure. However, it is necessary to set it at an intermediate level between the impact and the defective conveyance, and there is no choice but to make a compromise at an insufficient level in order to reduce the impact.

Therefore, in the present invention, the leading edge of the book original is the second.
To provide an automatic document feeder which can reduce the impact when it hits a conveying roller and prevent a reading failure such as a jitter from occurring, and also prevent an insufficient conveying force. It is an object.

[0011]

The invention according to claim 1 is
In order to solve the above-mentioned problems, in an automatic document feeder which transports a book document to a reading position and then discharges it, the book document is transported upstream from the reading position in the document transport direction. A first conveying roller, a first supporting unit that pushes up the first conveying roller when a book original enters, and supports the book original so as to move up and down according to the thickness of the book original; and a downstream side of the reading position in the original conveying direction. And a second supporting means for supporting the second conveying roller so as to move up and down in conjunction with a movement of the book conveying document pushed up by the first conveying roller. Variable means for varying the amount of vertical movement of the first transport roller and the second transport roller in accordance with the thickness of the book document, wherein the varying means is configured to increase as the thickness of the book document increases. First As the vertical movement of the second conveying roller than feed roller increases, it is characterized by varying the vertical movement amount of the second conveying roller.

In that case, conventionally, a shock (or vibration) is generated when the leading edge of the book document hits the second conveying roller.
As a result, the book original is disturbed during conveyance, and a reading error such as jitter occurs while the image of the original is being read.
In the present invention, as the thickness of the book manuscript increases, the first
Since the vertical movement amount of the second conveyance roller is variable so that the vertical movement amount of the second conveyance roller is larger than that of the conveyance roller, the leading edge of the book document smoothly enters the second conveyance roller and the impact ( (Or vibration) can be prevented, and it is possible to prevent reading errors such as jitter while reading the image of the original due to disturbance of the book original during transportation and side effects. Can be prevented.

According to a second aspect of the present invention, in order to solve the above-mentioned problems, in the first aspect of the invention, the changing means bends the outer peripheral portion of the first conveying roller when a book document is gripped during conveyance. When the amount is ΔL1 and the difference between the vertical movement amounts of the first conveyance roller and the second conveyance roller is Δ0, the movement amount of the second conveyance roller is changed so that 0 <ΔL0 ≦ ΔL1. I am trying.

In this case, if the amount of upward movement of the second conveying roller is too large as compared with the amount of upward movement of the first conveying roller, the conveying force is insufficient after the trailing edge of the original has passed the first conveying roller. However, in the present invention, as described above, 0 <ΔL0 ≦
Since the moving amount of the first conveying roller is changed so as to be ΔL1, it is possible to convey the book original with a strong conveying force by the second conveying roller, and prevent the insufficient conveying force and reliably convey the original. be able to.

In order to solve the above-mentioned problems, the invention according to claim 3 is the same as the invention according to claim 1 or 2, wherein the first supporting means and the second supporting means are composed of an integral supporting member, and The variable means comprises at least two connecting members, one end of which is connected to the support member and the other end of which is swingably supported by the automatic document feeder.
It is characterized in that a predetermined difference is provided in the swing radii of the at least two connecting members.

In this case, by providing a difference in the swinging radii of at least two connecting members, the vertical movement amount of the second conveying roller can be made larger than that of the first conveying roller. The cost can be reduced and the cost of the automatic document feeder can be prevented from increasing.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views showing a first embodiment of an automatic document feeder according to the present invention, and show an example in which the automatic document feeder of the present invention is attached to a copying machine as an image reading device. The image reading device can be applied to a facsimile device, a scanner device, and the like.

First, the structure will be described. In FIG. 1, 21
Is a copying machine, and a contact glass 22 is provided on the upper surface of the copying machine 21. Below the contact glass 22, a fluorescent lamp 23 as a reading device and a self-photolens array 24 are provided. The light emitted from the fluorescent lamp 23 to the book original through the contact glass 22 is reflected by the book original and guided to the photosensitive drum 25 via the lens array 24.

Since the photosensitive drum 25 is uniformly charged by the charging charger 26, the electrostatic latent image corresponding to the image of the book original is formed on the photosensitive drum 25 by the reflected light guided through the lens array 24. Is formed. This electrostatic latent image is developed by the developing device 27 to form a toner image (visualization), and this toner image is transferred to the roll-shaped recording paper 29 by the transfer charger 28. The separation charger 28a separates the photosensitive drum 25.

The roll-shaped recording paper 29 is a feeding roller.
After being fed by the photosensitive drum 30, it is timed by the registration roller 31 and the photosensitive drum 25 and the transfer charger.
The toner image is transferred by the transfer charger 28 at this time. The roll-shaped recording paper 29 after the toner image is transferred is cut by the cutter 32, the toner image is fixed by the fixing roller 33, and then the recording paper 29 is discharged to the transfer paper stacker 34. Further, after the residual toner is removed from the photosensitive drum 25 after the toner image is transferred by the cleaning device 35, the static electricity is removed by the static elimination lamp 36.

On the other hand, an automatic document feeder (hereinafter, simply referred to as ADF) 41 is provided on the upper surface of the copying machine 1. The ADF 41 is a book document inserted from a document table 42 through a document insertion opening 43. The 44 is conveyed onto the contact glass 22, and the book document 44, which has been read and image-formed as described above, is discharged onto the discharge tray 45.

The configuration of the ADF 41 will be specifically described below. 2 and 3, reference numeral 46 denotes a first conveying roller, which is made of rubber sponge and is arranged upstream of the contact glass 22 in the original conveying direction of the book original 44. Six sets of the first conveying rollers 46 are fixed to the second conveying roller shaft 48 via the flange 47.

The first conveyor roller shaft 48 has side plates 49a and 49b.
Is rotatably supported by a bearing 50, and a pulley 51a is attached to the end thereof. Also contact glass
A second document is provided on the downstream side of the book document 44 in the document transport direction with respect to
A carrying roller 53 is provided, and the second carrying roller 53 is provided.
6 sets are fixed to the second conveyance roller shaft 55 via the flange 54.

The second conveyor roller shaft 55 is provided with side plates 49a and 49b.
Is rotatably supported by a bearing 57 and has a second gear 58 attached to the end thereof. This second gear 58 meshes with a first gear 59 attached to the output shaft of the drive motor 60, and when the drive motor 60 is driven, the first gear 59 and the second gear
The driving force is transmitted via 58, so that the second carrying roller 53 is rotated via the second carrying roller shaft 55.

A pulley 51b is provided at the end of the second conveying roller shaft 55, and the pulley 51b is a drive belt.
The first conveyor roller 46 is connected to the pulley 51b via the drive roller 52 and is rotated by the rotation of the second conveyor roller shaft 53 being transmitted via the drive belt 52.
The side plates 49a and 49b are connected by a stay 61, and the stay 61 maintains rigidity. Further, two projecting members 62, 63 are attached to the side plate 49a, 49b, respectively. The projecting members 62, 63 are separated from a cover 66 fixed to the ADF 41 by a pair of links 64a, 64b forming a connecting member. It is loosely inserted into the projecting members 67 and 68 which project.

Therefore, the side plates 49a and 49b are adapted to move vertically with respect to the cover 66 in parallel with the carrying direction of the book original 44, and the first carrying roller 46 and the second carrying roller 53 also move vertically accordingly. To do. The cover 66 is detachably attached to the copying machine 21.
A spring 69 is contracted between the cover 66 and the cover 66, and the first transport roller 46 and the second transport roller 53 have side plates 49a and 49a.
It is urged downward by a spring 69 via b.

On the other hand, a first original detection sensor 70 is provided near the original insertion port 43, and the first original detection sensor 70 is provided.
Detects that the front end of the book document 44 has been inserted into the document insertion port 43 and outputs a signal to the controller. Based on this detection information, the controller drives the drive motor of the drive motor 60 after a lapse of a predetermined time to drive the first transport roller 46 and the second transport roller 53 to start the transport of the document.

A second document detecting sensor 71 is provided between the first conveying roller 46 and the contact glass 22.
The second document detection sensor 71 detects the leading edge of the book document 44 and outputs a signal to the controller.
Based on this detection signal, the controller recognizes that the conveyance of book document 44 has started. On the other hand, a pair of links
Of the links 64a and 64b, the link 64a located on the upper side is formed so as to have a larger swing radius than the link 64b located on the lower side, and the links 64a and 64b cause the book document 44 to move as shown in FIG. As the thickness of the
The second conveyance roller 53 is more than the vertical movement amount L1 of the conveyance roller 46.
Of the second transport roller 5 so that the vertical movement amount L2 of the
The vertical movement amount of 3 can be changed. In addition,
In FIG. 4, L1 is the first transport roller 46 from the document transport surface.
, L2 indicates the distance from the document transport surface to the center of the second transport roller 53.

Further, when the book original 44 is gripped during conveyance, the amount of bending of the outer periphery of the first conveying roller 46 is ΔL1, and the difference between the vertical movement amounts of the first conveying roller 46 and the second conveying roller 53 is Δ0. At this time, the movement amount of the second transport roller 53 is variable so that 0 <ΔL0 ≦ ΔL1. In the present embodiment, the side plates 49a and 49b constitute a first supporting means and a second supporting means that form a supporting member integrally formed, and the links 64a and 64b form a variable means.

1, 2 and 4, reference numeral 72 is an auxiliary first roller which comes into contact with the first conveying roller 46 via the book original 44 and rotates together with the first conveying roller 46.
Reference numeral 73 is an auxiliary second roller that comes into contact with the second transport roller 53 via the book document 44 and rotates together with the second transport roller 53. In FIG. 1, reference numeral 77 is a white roller that constitutes a white reference when reading an original, and the white roller 77 is a side plate 49.
Although it is attached to a and 49b, it is omitted in FIGS.

Next, the operation will be described. When the book document 44 starts to be transported, the first transport roller 46 moves upward by L1 against the biasing force of the spring 69 by the thickness of the book document 44, and in conjunction with this, the second transport roller 53. Has a link 64
It moves upward with a movement amount L2 larger than that of the first transport roller 46 via a and 64b.

When the trailing edge of the book original 44 passes the second conveying roller 53, the first conveying roller 46 and the second conveying roller 53 are urged by the spring 69 to move downward in parallel with the conveying surface. Return to the state of. Here, if the vertical movement amounts of the first conveyance roller 46 and the second conveyance roller 53 are the same,
The book original 44 is being conveyed by the impact (or vibration) when the leading edge of the book original 44 hits the second conveying roller 53.
Is disturbed, and a reading failure such as jitter occurs while the image of the original is being read.

In this embodiment, the link 64a is replaced with the link 64b.
The vertical movement of the first conveyance roller 46 is made larger than the vertical movement of the second conveyance roller 53 by making the swing radius larger than that of the second conveyance roller 53. The effect will be described with reference to FIG. As shown in FIG. 5A, the vertical movement amounts Y of the links 64a and 64b are the same, and the vertical movement amounts are X1 for the long link 64a of length r1 and short length of r2. The link 64b becomes X2, and the long link 64a has a short movement amount.
It becomes larger than the movement amount of 4b. For this reason, link 64
a and 64b are inclined so that the downstream side of the side plates 49a and 49b in the document transport direction is positioned higher than the upstream side by the amount of the difference (X1−X2) in the horizontal movement amount (see FIG. 5B). The second carrying roller 53 is located above the first carrying roller 46.

Further, when the book original 44 is not gripped, the downstream side and the upstream side of the side plates 49a and 49b in the original conveying direction become parallel to the original conveying surface (see FIG. 5C), and the second conveying roller 53 It is located on the same line as the first transport roller 46.
The inclination θ at this time is set based on the equation.
However, in the formula, Z is the side plates 49a, 49b of the link 64a.
It is the distance between the rocking fulcrum S on the side and the rocking fulcrum M on the side plates 49a and 49b of the link 64b.

[0035]

[Equation 1]

For this reason, as described above, when the book original 44 is conveyed, as the book original 44 becomes thicker, the vertical movement amount of the second conveyor roller 53 becomes larger than that of the first conveyor roller 46 so that the link 64a. , 64b change the vertical movement amount of the second conveying roller 53, so that it is possible to prevent the leading edge of the book document 44 from smoothly entering the second conveying roller 53 and generating an impact (or vibration). Therefore, it is possible to prevent a reading error such as a jitter from occurring while the book document is disturbed during conveyance and the image of the document is being read, and it is possible to prevent a side effect from occurring.

If the amount of upward movement of the second conveying roller 53 is too large as compared with the amount of upward movement of the first conveying roller 46, the trailing edge of the book original 44 passes through the first conveying roller 46. After that, there is a possibility that the conveyance force becomes insufficient and a conveyance failure occurs. In this embodiment, the book original 44
Δ is the amount of deflection of the outer peripheral portion of the first transport roller 46 when gripping
When L1 is set and the vertical movement difference between the first conveyance roller 46 and the second conveyance roller 53 is set to Δ0, the movement amount of the second conveyance roller 53 is changed by the links 64a and 64b so that 0 <ΔL0 ≦ ΔL1. Therefore, the book conveying original document 44 can be conveyed by the second conveying roller 53 with a strong conveying force, and it is possible to prevent the insufficient conveying force from occurring and to reliably convey the original document.

Further, in the present embodiment, the mechanism having such an effect is provided with a link 64 having a predetermined difference in swing radius.
Since it can be achieved by providing a and 64b, the structure of the variable means can be made inexpensive, and the cost of the ADF 41 can be prevented from increasing. In the present embodiment, the first transport roller 46 and the second transport roller 53 are made of rubber sponge, but the invention is not limited to this and may be made of rubber.

FIG. 6 is a diagram showing a second embodiment of the automatic document feeder according to the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG.
Reference numerals 81 and 82 are links that are formed to have different lengths L1 and L2 and intersect with each other with the center portion as a fulcrum. At both ends of these links 81 and 82, long holes 81a, 81b and 82, respectively.
a and 82b are formed.

One ends of the brackets 81 and 82 are slidably fitted into projecting members 84 and 85 projecting from the bracket 83 provided on the cover 66.
The other end portions of the 81 and 82 project from the side plates 49b by the projecting members 86 and 87.
The long holes 81b and 82b are slidably fitted in. In addition,
Links similar to the links 81 and 82 are also provided on the side plate 49a side, but the illustration is omitted because they have the same configuration.

Further, one end of the long link 81 is slidably attached to the bracket 83 at a position upstream in the document conveying direction, and the other end of the long link 81 is arranged in the document conveying direction. It is slidably attached to the side plates 49a and 49b at the downstream position. In the present embodiment, the links 81 and 82 form variable means. Even in the present embodiment, the long link 81 and the short link 82 are provided so as to intersect with each other to form the long link.
The other end of 81 is provided with a side plate 49a at a position on the downstream side in the document transport direction,
By being slidably attached to the 49b, the swing radius of the link 81 can be made larger than the swing radius of the link 82, and the downstream sides of the side plates 49a and 49b in the document transport direction are located above the upstream side. Can be tilted like. Therefore, as the book document 44 becomes thicker, the vertical movement amount of the second conveyance roller 53 can be made larger than the vertical movement amount of the first conveyance roller 46, and the same effect as that of the first embodiment can be obtained. be able to. Even in the present embodiment, the first transport roller 46 when the book document 44 is gripped at the time of transport
The bending amount of the outer peripheral portion is set to ΔL1, and the first conveying roller 46 and the second conveying roller 46
When the difference in the amount of vertical movement of the transport roller 53 is Δ0, 0 <
It goes without saying that the lengths and attachment positions of the links 81 and 82 are set so that the movement amount of the second transport roller 53 is changed so that ΔL0 ≦ ΔL1.

FIG. 7 is a diagram showing a third embodiment of the automatic document feeder according to the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG.
A gear 91 having a number of teeth A is rotatably provided on the side plate 49b. This gear 91 is a gear 92a inside the two-stage gear 92 rotatably provided on the side plate 49b (the number of teeth is the same as that of the gear A). )
Meshes with. Further, the gear 91 meshes with a rack 93 provided on the cover 66, and a gear 92b outside the two-stage gear 92 is provided.
The rack 94 provided on the cover 66 is meshed with (having the number of teeth B larger than the number of teeth A). In this embodiment, the gear 91
And the two-stage gear 92 constitutes a variable means. Although the same structure as the gear 91, the two-stage gear 92, and the racks 93 and 94 is provided on the side plate 49a side, the illustration thereof is omitted.

In this embodiment, the gear 91 rotates along the rack 93 when the first transport roller 46 and the second transport roller 53 move upward, and the inner side of the two-stage gear 92 meshing with the gear 91. The outer gear 92b rotates along the rack 94 as the gear 92 rotates. At this time, since the number of teeth B of the outer gear 92b is larger than the number of teeth A of the gear 91, the side plates 49a, 49a
It is possible to incline the downstream side of the document conveyance direction b so as to be located above the upstream side. For this reason, the book manuscript 44
As the thickness increases, the vertical movement amount of the second conveyance roller 53 can be made larger than the vertical movement amount of the first conveyance roller 46, and the same effect as that of the first embodiment can be obtained.

Even in this embodiment, the amount of deflection of the outer peripheral portion of the first conveying roller 46 when the book original 44 is gripped during conveyance is set to ΔL1, and the first conveying roller 46 and the second conveying roller 53 are vertically moved. When the difference of the movement amount is Δ0, 0 <ΔL0 ≦ Δ
It goes without saying that the number of teeth of the gear 91 and the two-step gear 92 is set so that the moving amount of the second transport roller 53 is changed to L1.

[0045]

According to the first aspect of the present invention, as the thickness of the book original becomes thicker, the second feeding roller than the first feeding roller is moved.
Since the vertical movement amount of the second conveyance roller is variable so that the vertical movement amount of the conveyance roller becomes large, the leading edge of the book document smoothly enters the second conveyance roller and an impact (or vibration) occurs. It is possible to prevent the occurrence of a reading error such as a jitter while reading the image of the original due to the disorder of the book original during the transportation and the occurrence of side effects. can do.

According to the second aspect of the present invention, the book original can be conveyed with a strong conveying force by the second conveying roller, and the original can be surely conveyed while preventing the insufficient conveying force. . According to the third aspect of the present invention, by providing the swing radii of the at least two connecting members to be different, the vertical movement amount of the second transport roller can be made larger than that of the first transport roller, so that it is variable. The structure of the means can be made inexpensive, and the cost of the automatic document feeder can be prevented from increasing.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an automatic document feeder according to the present invention, and is a schematic configuration diagram of a copying machine equipped with the automatic document feeder.

FIG. 2 is a schematic configuration diagram of an automatic document feeder according to the first embodiment.

FIG. 3 is a sectional view of the automatic document feeder according to the first embodiment.

FIG. 4 is a diagram showing a state in which a document is gripped by a first transport roller of the first embodiment.

5A is a diagram showing a swinging state of a link of the first embodiment, FIG. 5B is a diagram showing a tilt of a side plate when a document is gripped by the first and second conveyance rollers, and FIG. Is the first and second
It is a figure which shows the state of the side plate at the time of standby of a conveyance roller.

FIG. 6 is a schematic configuration diagram showing a second embodiment of an automatic document feeder according to the present invention.

FIG. 7 is a schematic configuration diagram showing a third embodiment of an automatic document feeder according to the present invention.

FIG. 8 is a schematic view of a conventional automatic document feeder.

[Explanation of symbols]

22 Contact Glass (Reading Position) 41 ADF (Automatic Document Feeder) 44 Book Document 46 First Transport Rollers 49a, 49b Side Plates (First Support Means, Second Support Means, Support Members) 53 Second Transport Rollers 64a, 64b Links (Variable means) 81, 82 Link (variable means) 91 Gear (variable means) 92 Two-stage gear (variable means) 93, 94 Rack (variable means)

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-4-17454 (JP, A) JP-A-4-85232 (JP, A) JP-A-5-24707 (JP, A) JP-A-8- 40597 (JP, A) JP 57-82857 (JP, A) JP 57-93359 (JP, A) JP 57-137857 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/00-1/00 108 H04N 1/04-1/207 G03G 15/00 107 B65H 5/02 B65H 5/06 B65H 5/22 B65H 29/12-29/24 B65H 29 / 32 G03B 27/58-27/64

Claims (3)

(57) [Claims] 1. An automatic document feeder for transporting a book document to a reading position and then ejecting the book document, which is arranged upstream of the reading position in the document feeding direction,
A first conveying roller that conveys a document, a first supporting unit that pushes up the first conveying roller when a book document enters, and supports the book document so as to move up and down according to the thickness of the book document; It is arranged on the downstream side in the transport direction,
A second transport roller for transporting the document; a second support unit for supporting the second transport roller so as to move up and down in conjunction with a movement of the book document pushed up by the first transport roller; A changing unit that changes the vertical movement amount of the roller and the second conveying roller in accordance with the thickness of the book original, the changing unit being more than the first conveying roller as the thickness of the book original becomes thicker. Also, in the automatic document feeder, the vertical movement amount of the second conveyance roller is changed so that the vertical movement amount of the second conveyance roller becomes large. 2. The variable means sets a deflection amount ΔL of an outer peripheral portion of the first transport roller when a book document is gripped during transport.
When the difference between the vertical movement amounts of the first conveyance roller and the second conveyance roller is Δ0, the movement amount of the second conveyance roller is changed so that 0 <ΔL0 ≦ ΔL1. The automatic document feeder according to claim 1. 3. The first supporting means and the second supporting means are composed of an integral supporting member, and the variable means has one end connected to the supporting member and the other end connected to the automatic document feeder. 3. The automatic document feeder according to claim 1, wherein the automatic document feeder is composed of at least two connecting members that are swingably supported, and the swing radii of the at least two connecting members are provided with a predetermined difference. apparatus.