JP2021087154A - Automatic document reading device and image forming apparatus - Google Patents

Abstract

To provide an automatic document feeder that can prevent the occurrence of partial expansion and contraction of an image occurring in image data due to variations in speed without performing a step of detecting a defective image, and an image forming apparatus.SOLUTION: An automatic document reading device 6 comprises: roller pairs 17, 18, 20 that convey a document 7; and a reading member 29 that reads an image of the document 7 conveyed by the roller pairs 17, 18, 20. The automatic document reading device causes the reading member 29 to read the same image a plurality of times under different conditions together with positional information, deletes an image of a predetermined range set in advance in one image, and complements an image of the predetermined range in the other image different from one image into one image as image data of the document 7.SELECTED DRAWING: Figure 9

Description

The present invention relates to an automatic document reader and an image forming apparatus.

As a method for reading an original image in an image forming apparatus equipped with an automatic original reading device that automatically conveys originals one by one from a bundle of originals placed on an original tray, a contact glass is used while driving a traveling body to move the reading position. A so-called book-type reading method for reading the above original image and a so-called sheet-through type reading method in which the image reading unit is fixed and the original is conveyed at a constant speed are known.
In the sheet-through type scanning method, the document is automatically transported to the scanning position from the document bundle set in the automatic document scanning device and the scanning operation is performed. Therefore, the productivity of document scanning is improved as compared with the book type scanning method. It has the advantage of being able to improve. Recently, in order to further improve the productivity of the sheet-through type reading method, the document reading speed has been increased.

In the sheet-through type scanning method, if the document transport speed is always constant, there is no problem with the output image, but the document transport speed actually fluctuates suddenly. For example, when a document is inserted between the transfer rollers, the diameter of the transfer roller changes slightly depending on the thickness of the transferred document as compared with the case where the document is not inserted, and the angular velocities are the same. However, the peripheral speed of the transport roller is lower than when the document is not transported. Therefore, the peripheral speed of the transport roller increases at the moment when the document is removed from the transfer roller, and the transfer roller pushes out the rear end of the document removed from the transfer roller, resulting in speed fluctuation. Further, when an attempt is made to insert a document between the transfer rollers in the pressure contact state, a large load acts on the transfer rollers, the transfer speed of the tip of the document slows down, and the speed fluctuates. In this way, when the original is inserted between the conveying rollers and when the original is pulled out from between the conveying rollers, the conveying speed of the original changes, and if the conveying speed of the original becomes uneven, the image data to be read is partially There was a problem that the image was stretched or shrunk.

In the automatic document reading device, a technique for miniaturizing the speed fluctuation of a document in a transport path is known, but there is a problem that a slight speed fluctuation remains in such a technique so far.
Further, when a document is set on the contact glass of a book-type image forming apparatus, a technique is known in which a scanner reciprocates to read the document image twice to remove a defective image, but such a configuration is automatic. There is a problem that the productivity is inferior to that of the document reader.
In order to solve the above-mentioned problems, in a configuration in which a document is conveyed to an image reading unit and the same document surface is read twice, a defective image occurs when dust or other deposits are present on the image reading unit and streak noise is generated. A technique has been proposed in which images are synthesized and used without defects (see, for example, "Patent Document 1").

However, the above-mentioned technique has a problem that an extra step of comparing images to detect a location where a defect has occurred is required. Further, a method of simply averaging images read multiple times by an automatic document reader is known. This method does not require a step of detecting a defective part, but a beautiful image is reproduced when a defect occurs in the same part. There was a problem that it could not be done. Further, although a technique for complementing a missing image by image processing from surrounding pixels is known, there is a problem that the complemented image is different from the original image because the missing part does not have the original image.
The present invention solves the above-mentioned problems, and can suppress the occurrence of partial image expansion and contraction that occurs in image data due to speed fluctuations without performing a defect image detection step. An object of the present invention is to provide a reading device and an image forming device.

The invention according to claim 1 includes a roller pair that conveys a document and a reading member that reads an image of the document conveyed by the roller pair, and the same image is read a plurality of times under different conditions by the reading member. The image of the predetermined range in one image is deleted, and the image of the predetermined range in another image different from the one image is complemented with the one image. It is characterized in that it is image data of a manuscript.

According to the present invention, it is possible to suppress the occurrence of partial image expansion and contraction that occurs in image data due to speed fluctuations without performing a defect image detection process or a comparison of scanned images. A reader can be provided.

It is a schematic block diagram of the image forming apparatus to which one Embodiment of this invention is applied. It is a schematic block diagram of the automatic document transfer apparatus which concerns on one Embodiment of this invention. It is a block diagram of the controller part used in one Embodiment of this invention. It is a schematic diagram of the main part of the automatic document transfer apparatus which concerns on the modification of one Embodiment of this invention. It is a schematic diagram of the main part of the automatic document transfer apparatus explaining the place where the speed fluctuation of a document occurs in one Embodiment of this invention. It is a schematic diagram of the main part of the automatic document transfer apparatus explaining the place where the speed fluctuation of a document occurs in one Embodiment of this invention. It is a schematic diagram of the main part of the automatic document transfer apparatus explaining the place where the speed fluctuation of a document occurs in one Embodiment of this invention. It is the schematic explaining the expansion and contraction which occurred in the manuscript in one Embodiment of this invention. It is a schematic diagram of the main part of the automatic document transfer apparatus which concerns on another modification of one Embodiment of this invention. It is a schematic diagram of the main part of a manuscript for demonstrating the manuscript image reading operation in 1st Embodiment of this invention. It is a schematic diagram of the main part of the manuscript for demonstrating the manuscript image reading operation in the 2nd Embodiment of this invention. It is the schematic explaining the image reading sensor used in the 3rd Embodiment of this invention. It is a schematic diagram of the main part of the automatic document transporting apparatus explaining the 5th Embodiment of this invention.

FIG. 1 is a schematic front view of an image forming apparatus according to an embodiment of the present invention. In the figure, the full-color copying device 1 which is an image forming device includes a reading device 2 for reading the contents of a document, an automatic document transporting device 3 for automatically transporting a document, and a paper feeding device for supplying a transfer sheet S as a recording medium. 4. It has an image forming unit 5 and the like that form an image on the transfer sheet S. In the present embodiment, the copying device 1 using toners of four colors (black (K), cyan (C), magenta (M), and yellow (Y)) as the image forming device will be described as an example, but the image forming device will be described as an example. May be a monochrome image forming apparatus. The copying device 1 constitutes an automatic document reading device 6 by a reading device 2 and an automatic document transporting device 3.

The reading device 2 is mounted on the upper part of the copying device 1, and includes an irradiation unit 21 that irradiates the document with light, a first mirror 22a and a second mirror 22b and a third mirror 22c that bend the light reflected from the document, and a lens. 23, it has an image pickup device 24 which is a reading unit for a CCD or the like, an image processing substrate 25, and the like. A close contact image sensor that integrates the functions of the irradiation unit 21 and the imaging device 24 may be arranged above the reading device 2 to read the image of the document transported by the automatic document transporting device 3.
A contact glass 26 on which a document can be placed is arranged on the upper surface of the reading device 2. Above the reading device 2, an automatic document transporting device 3, which is a feature of the present invention, is arranged. The automatic document transfer device 3 will be described later.

The paper feed device 4 is provided corresponding to the paper feed cassettes 41a, 41b, 41c for accommodating the transfer sheet S and the paper feed cassettes 41a, 41b, 41c, respectively, and the paper feed means 42a, 42b for feeding the transfer sheet S. , 42c, a paper feed transporting means 43 for transporting the transfer sheet S fed from each of the paper feed cassettes 41a, 41b, 41c to the image forming unit 5, a paper feed transport path 44 for feeding the transfer sheet S, and the like. doing.

The image forming unit 5 is an exposure device 51, black (K), cyan (C), magenta (M), yellow (M) that outputs image information of a document obtained by the reading device 2 or the automatic document feeding device 3 as an image signal. It has photoconductor drums 52a, 52b, 52c, and 52d that carry the toner images of each color of Y). Further, the image forming unit 5 develops a toner image of each color on the charging devices 53a, 53b, 53c, 53d and the photoconductor drums 52a, 52b, 52c, 52d for charging the photoconductor drums 52a, 52b, 52c, 52d. It has devices 54a, 54b, 54c, 54d. Further, the image forming unit 5 transfers the primary transfer image on the intermediate transfer belt 55 and the intermediate transfer belt 55 on the transfer sheet S to the intermediate transfer belt 55 on which the toner images of each color formed on the photoconductor drums 52a, 52b, 52c, 52d are primarily transferred. It has a secondary transfer roller 56 for secondary transfer.

Further, the image forming unit 5 uses a fixing device 57 for fixing the full-color toner image secondarily transferred on the transfer sheet S on the transfer sheet S by heat and pressure, and the transfer sheet S sent from the paper feed transfer path 44. It has a sheet transport path 58a for transporting to the fixing device 57. Further, the image forming unit 5 provides images on both sides of the paper ejection tray 59 on which the image-formed transfer sheet S is loaded, the paper ejection transport path 58b for transporting the transfer sheet from the fixing device 57 to the paper ejection tray 59, and the transfer sheet S. It has a switchback transfer path 58c and a double-sided transfer path 58d used for forming.

Next, a series of operations for forming an image of the contents of the original on the transfer sheet S by the copying apparatus 1 will be described.
The document conveyed by the automatic document transfer device 3 is irradiated with light from the light source of the irradiation unit 21, and after the reflected light is photoelectrically converted, an image signal which is a surface-read image is output to the exposure device 51. The reflected light of the document is signalized by the lens 23, the image pickup apparatus 24, and the image processing substrate 25 by refraction of the mirrors 22a, 22b, and 22c.

In the case of single-sided image formation, an image signal is sent to the image forming unit 5 after the surface image of the original is read by the reading device 2, but in the case of double-sided image forming, one side is sent by the reading device 2. Is started to be read, and then the other side is started to be read, so that the image information on both sides is output to the exposure apparatus 51.
Further, the automatic document transfer device 3 is connected to the reading device 2 by a hinge so as to be openable and closable, so that the automatic document transfer device 3 can be opened. To read the image information in a book-type document that does not automatically convey the document, the irradiation unit 21 moves in the sub-scanning direction according to the size of the document while the document is placed on the contact glass 26, so that the image of the document is read. Read the information.
In conjunction with the timing at which the original image information is read and the image signal is output to the exposure apparatus 51, for example, the transfer sheet S housed in the paper feed cassette 41a is secondary by the paper feed means 42a and the paper feed transport means 43. It is conveyed to the contact portion between the transfer roller 56 and the intermediate transfer belt 55.

The exposure apparatus 51 that receives the image signal irradiates the laser beam L toward the photoconductor drums 52a, 52b, 52c, and 52d. As a result, electrostatic latent images are formed on the photoconductor drums 52a, 52b, 52c, and 52d whose surfaces are charged to a predetermined potential by the charging devices 53a, 53b, 53c, and 53d in advance. Then, each color toner is supplied from each developing device 54a, 54b, 54c, 54d to each formed electrostatic latent image, and each electrostatic latent image is visualized. The color toner images on the visualized photoconductor drums 52a, 52b, 52c, and 52d are superimposed and transferred to the intermediate transfer belt 55 in such a manner that they are superimposed, whereby the full-color toner image is formed on the intermediate transfer belt 55. It is formed.

The full-color toner image formed on the intermediate transfer belt 55 is collectively secondary-transferred to the transfer sheet S conveyed at the position facing the secondary transfer roller 56, whereby the full-color toner image is transferred onto the transfer sheet S. Is transcribed. The transfer sheet S to which the full-color toner image is transferred is sent to the fixing device 57 to fix the full-color toner image by heat and pressure. The transfer sheet S on which the full-color toner image is fixed is discharged onto the paper discharge tray 59 via the paper discharge transport path 58b.
By the series of operations described above, the image formation on one surface of the transfer sheet S is completed. When image formation is performed on both sides of the transfer sheet S, after the image formation on one surface of the transfer sheet S is completed in the fixing device 57, the transfer sheet S is conveyed to the switchback transfer path 58c to carry the transfer sheet S. After reversing the transfer direction, the transfer sheet S is transferred to the double-sided transfer path 58d and again transferred to the position opposite to the intermediate transfer belt 55 and the secondary transfer roller 56. The transfer sheet S whose front and back sides are inverted is discharged onto the paper ejection tray 59 via the fixing device 57 and the paper ejection transport path 58b in the same manner as described above after the back surface image is formed on the other side.

FIG. 2 is a schematic configuration diagram of a sheet-through type ADF which is an automatic document transporting device 3 according to the present embodiment, and FIG. 3 is a diagram illustrating a control configuration of the automatic document transporting device 3.
The automatic document transporting device 3 transports an image as a sheet (including the concept of both a single sheet and a bundle consisting of a plurality of stacked sheets) to a fixed scanning device site at a predetermined speed while transporting an image by the scanning device. Read.
An example of the basic configuration, operation, and operation will be described below. As shown in FIG. 2, the automatic document transfer device 3 is a separate feeding unit that separates and feeds the original 7 from the original setting unit A for setting the original 7 and the set plurality of originals 7 one by one. B. It has a resist unit C that temporarily abuts and aligns the fed document 7 and pulls out and conveys the aligned document 7. Further, the automatic document transfer device 3 is a device for reading the surface image of the turn portion D and the document 7 from below the second contact glass 27, which turns the transferred document 7 and conveys the document surface downward on the reading side. The first reading and conveying unit E to be read by the first image reading sensor 29 composed of the close contact image sensor which is the reading member inside, and the back surface image of the document 7 is read by the second image reading sensor 19 which is an image reading means after reading the front surface image. It has a second reading / conveying unit F for making the image. Further, the automatic document transfer device 3 has a paper discharge unit G that discharges the documents 7 whose front and back sides have been read to the outside of the device, a stack unit H that loads and holds the documents 7 after the reading is completed, and a drive that drives these transfer operations. It has units 61 to 65 (see FIG. 3) and a controller unit 60 (see FIG. 3) as a control means for controlling a series of operations.
As shown in FIG. 3, the controller unit 60 is connected to the main body control unit 9 that controls the entire copying apparatus 1 via the interface I / F8. An operation unit 10 in which the user of the copying apparatus 1 performs each main operation is connected to the main body control unit 9. The controller unit 60 has an image processing unit 77 inside the image processing unit 77 that stores and transforms the images read by the sensors 19 and 29.

As shown in FIG. 2, the document 7 to be read is set on the document table 32 including the movable document table 31, and the document 7 is set with the image surface facing upward. The document 7 is positioned in a direction (main scanning direction) orthogonal to the document transport direction by a side fence (not shown).
The set of the document 7 is detected by the set filler 33 and the document set sensor 34 which is turned on and off by the set filler 33, and is transmitted to the main body control unit 9 by the interface I / F8. The sheet detecting means is composed of the set filler 33 and the document set sensor 34.
The length of the document 7 in the transport direction is roughly determined by the document length detection sensors 35 and 36 provided on the document table 32. As the document length detection sensors 35 and 36, a reflective sensor or an actuator type sensor capable of detecting even one document 7 is used. The sensors 35 and 36 are arranged so that at least the vertical or horizontal size of a document of the same size can be determined.

The movable document table 31 can be moved up and down in the directions a and b shown in FIG. 2 by a bottom plate raising motor 65 (see FIG. 3) as a table driving means, and the sheet detecting means means that the document 7 is set. The movable document table 31 is raised so that the top surface of the document 7 comes into contact with the pickup roller 37 by rotating the bottom plate raising motor 65 in the normal direction.
The pickup roller 37 is displaced in the directions of arrows c and d shown in FIG. 2 by a cam mechanism to which the pickup elevating motor 61 (see FIG. 3) is connected. Then, the pick-up roller 37 is pushed by the upper surface of the document on the movable document table 31 as the movable document table 31 rises and rises in the direction of arrow c, and the upper limit is detected by the table rise detection sensor 38. The movable document table 31 occupies a home position which is a lower limit position when the document 7 is not set, and this home position position is detected by the bottom plate home position sensor 47.

When the print key provided on the operation unit 10 (see FIG. 3) is pressed by the device user and a document transfer signal is transmitted from the main body control unit 9 to the controller unit 60 via the interface I / F8, the pickup roller 37 Is rotationally driven by the forward rotation of the paper feed motor 62 (see FIG. 3), and picks up several (ideally one) documents 7 on the document table 32. The document transport belt 39 is driven in the paper feed direction by the forward rotation of the paper feed motor 62, and the reverse roller 11 is rotationally driven in the direction opposite to the document transport direction by the forward rotation of the paper feed motor 62. As a result, the top-level document 7 and the document 7 below it are separated, and only the top-level document 7 is conveyed. The document transport belt 39 and the reverse roller 11 constitute a separate feeding means.

More specifically, the reverse roller 11 is in contact with the document transport belt 39 at a predetermined pressure, and when it is in direct contact with the document transfer belt 39 or in a state of being in contact with the document transfer belt 39 via one document 7, the document transfer belt 39 It rotates counterclockwise according to the rotation of.
When two or more originals enter between the document transport belt 39 and the reverse roller 11, the driven rotational force is set to be lower than the torque of the torque limiter, and the reverse roller 11 is originally It rotates clockwise, which is the driving direction, and pushes back excess documents to prevent double feeding.

Due to the action of the document transport belt 39 and the reverse roller 11, the document 7 separated into one sheet is further fed by the document transport belt 39, and after the tip is detected by the abutting sensor 12, the document 7 is further advanced and stopped. The tip is brought into contact with the pull-out roller pair 13.
After that, the document 7 is sent by a predetermined amount from the detection of the abutting sensor 12 by a predetermined distance, and as a result, is pressed against the pull-out roller pair 13 with a predetermined amount of deflection. Then, by stopping the paper feed motor 62 in this state, the driving of the document transport belt 39 is stopped. At this time, the pickup roller 37 is retracted from the upper surface of the document 7 by rotating the pickup lifting motor 61, and the document 7 is fed only by the transport force of the document transport belt 39, so that the tip of the document 7 is a pull-out roller pair 13. The tip is aligned (skew correction) by entering the nip.

The pull-out roller pair 13 has the skew correction function described above, and is a roller for transporting the skew-corrected document 7 after separation to the intermediate roller pair 14, and is driven by the reversal of the paper feed motor 62. When the paper feed motor 62 is reversed, the pull-out roller pair 13 and the intermediate roller pair 14 are both driven, but the pickup roller 37 and the document transport belt 39 are not driven together.
A plurality of document width sensors 15 are arranged side by side in the paper surface direction in FIG. 2, and detect the size in the width direction orthogonal to the transport direction of the document 7 conveyed by the pull-out roller pair 13.
As for the length of the document 7 in the transport direction, the length of the document 7 is detected from the motor pulse by reading the front and rear ends of the document 7 with the abutting sensor 12.
When the document 7 is conveyed from the resist unit C to the turn unit D by driving the pull-out roller pair 13 and the intermediate roller pair 14, the transfer speed at the resist unit C is higher than the transfer speed at the first reading transfer unit E. Is also set at a high speed to shorten the processing time for feeding the document 7 to the first image reading sensor 29.

When the tip of the document 7 is detected by the scanning inlet sensor 16, the pull-out roller pair is used to make the document transport speed equal to the scanning transport speed before the tip of the document 7 enters the nip of the scanning inlet roller pair 17. Deceleration of 13 and intermediate roller vs. 14 is started. At the same time, the reading motor 63 is driven in the forward direction to drive the reading inlet roller pair 17, the reading outlet roller pair 18, the second image reading sensor 19, and the outlet roller pair 20. The intermediate roller pair 14 and the reading inlet roller pair 17 constitute a conveying means.

When the tip of the document 7 is detected by the resist sensor 28, the transport speed of the document 7 is decelerated over a predetermined transport distance, and the controller unit 60 is at the reading position of the first image reading sensor 29 on the second contact glass 27. The document 7 is temporarily stopped in front of the user, and a resist stop signal is transmitted to the main body control unit 9 via the interface I / F8. Subsequently, when a reading start signal is transmitted from the main body control unit 9 to the controller unit 60, the controller unit 60 determines the temporarily stopped document 7 until the tip reaches the reading position of the first image reading sensor 29. The speed is increased so that the speed rises to the transport speed of. At this time, at the timing when the tip of the document 7 detected by the pulse count of the reading motor 63 reaches the first image reading sensor 29, the sub-scanning direction effective image area of the first surface of the document 7 with respect to the main body control unit 9 The gate signal indicating the above is transmitted through the first image reading sensor 29 until the rear end of the document 7 is removed. Then, while the document 7 is conveyed by the drive of the reading inlet roller pair 17 and the scanning outlet roller pair 18, the first image reading sensor 29 reads the first surface image, that is, the surface image of the document 7.

In the case of single-sided document scanning, the document 7 that has been read by the first image reading sensor 29 in the first scanning and transporting unit E passes through the second scanning and transporting unit F and is transported to the paper ejection unit G. At this time, when the tip of the document 7 is detected by the paper ejection sensor 40, the controller unit 60 drives the paper ejection motor 64 in the forward rotation to rotate the paper ejection roller pair 45 in the counterclockwise direction. Further, the controller unit 60 drives the paper ejection motor 64 immediately before the rear end of the document 7 comes out of the nip of the paper ejection roller vs. 45 based on the paper ejection motor pulse count from the tip detection of the document 7 by the paper ejection sensor 40. Is decelerated to control so that the document 7 ejected onto the output tray 46 does not pop out.

On the other hand, in the case of double-sided document reading, the tip of the document is detected by the paper ejection sensor 40, the tip position of the document 7 being conveyed is detected by the pulse count of the scanning motor 63, and the document is detected by the second image reading sensor 19. At the timing when the tip of the 7 reaches, the second image reading sensor 19 receives a gate signal from the controller unit 60 indicating an effective image area in the sub-scanning direction on the second surface, that is, the back surface of the document 7. 19 is transmitted until the rear end of the document 7 is removed.
Then, while the document 7 is conveyed by the drive of the reading outlet roller pair 18 and the outlet roller pair 20, the back surface image of the document 7 is read by the second image reading sensor 19 by the document scanning method (sheet-through reading method). .. The white reference roller 48 arranged to face the second image reading sensor 19 suppresses the floating of the document 7 in the second image reading sensor 19 and is white for acquiring shading data in the second image reading sensor 19. Also serves as a reference member.

A translucent member constitutes a document reading surface by the second image reading sensor 19 so as to face the second image reading sensor 19 as an image reading means including a close contact image sensor. A white reference roller 48, which is arranged so as to face the second image reading sensor 19, is arranged via the translucent member.
The translucent member is arranged on the second image reading sensor 19 side as one transport guide that forms the transport path of the document 7, and the white reference roller 48 serves as the other transport guide that forms the transport path of the document 7.
As a result, the automatic document transfer device 3 is configured.

FIG. 4 shows an automatic document transfer device 30 according to a modified example of the embodiment of the present invention. The automatic document transfer device 30 is mainly different from the automatic document transfer device 3 shown in FIG. 2 in that it does not have the second image reading sensor 19, and has the same configuration as the automatic document transfer device 3. Have similar reference numerals, and detailed description of each is omitted.
When scanning double-sided documents, the document 7 sent out from the pull-out roller pair 13 is conveyed to the first image reading sensor 29 via the transport path 49 and the scanning inlet roller pair 17, and the surface image is captured by the first image reading sensor 29. Can be read. The document 7 on which the surface image has been read is sent to the switchback transport path 66 via the reading outlet roller pair 18 and the transport path 50. The switchback transport path 66 is provided with a switching plate 67 for switching the transport destination of the document 7, and a reversing roller pair 68 is provided on the downstream side thereof. The switching plate 67 is selectively positioned at the position A shown by the solid line and the position B shown by the broken line by a switching means (not shown), and the reversing roller pair 68 is rotated forward and reverse by a drive motor (not shown).

When the document 7 is sent to the switchback transport path 66, the reversing roller 68 is rotating clockwise in the clockwise direction in FIG. 4, and the switching plate 67 is held at the position B. The document 7 sent to the switchback transport path 66 has its rear end passing through the paper ejection roller pair 45 and traveling a certain distance, and then the reversing roller 68 reverses in the counterclockwise direction in FIG. 4 and the switching plate 67. Is displaced to position A and is sent to the reverse transport path 69.
The document 7 sent to the reverse transfer path 69 is conveyed by the rotation of the paper ejection roller pair 45, and then the back image is captured by the first image reading sensor 29 via the pullout roller pair 13, the transport path 49, and the reading inlet roller pair 17. Can be read.
When the original 7 is ejected as it is after reading the back image, the original 7 is guided by the switching plate 67 occupying the position A via the transport path 50 and the paper ejection roller vs. 45 and ejected onto the paper ejection tray 46. Will be done. On the other hand, when the document 7 is inverted again to align the page order, the document 7 is switched back and conveyed via the switching plate 67 and the switchback transfer path 66 in the same manner as described above, and then the reverse transfer path 69, respectively. It is discharged to the output tray 46 via the transport paths 49 and 50.

In the automatic document transporting device 3 shown in FIG. 2 and the automatic document transporting device 30 shown in FIG. 4 described above, the transport speed of the document fluctuates due to the document transport path, and the document is transported from one end to the other end in the document transport direction. Stretching and shrinking occur in the images in a predetermined range between them. The mechanism by which stretching and shrinking occur in such an image will be described below.
FIG. 5 is a schematic view of a main part of FIG. 2, which is a diagram showing speed fluctuations that occur in the document 7 due to the transport resistance of the document 7 by the guide plate. As described above, the document 7 is conveyed toward the first image reading sensor 29 by the scanning inlet roller pair 17, but the tip of the document 7 beyond the first image reading sensor 29 is conveyed by the first image reading sensor 29. It collides with the end side of the guide plate 70 provided on the downstream side in the direction. Due to this collision, the transport speed of the document 7 is reduced, and the document 7 is read by the first image reading sensor 29 in a state where the speed is reduced. Therefore, as shown in FIG. 8A, the image of the document 7 is stretched 71. The stretch 71 of the image is generated from a predetermined position separated by a distance K with respect to the tip of the document 7 in the transport direction. As shown in FIG. 5, the distance K corresponds to the distance between the image reading position of the document 7 by the first image reading sensor 29 and the position where the tip of the document 7 collides with the guide plate 70.

FIG. 6 is a schematic view of a main part of FIG. 2, which is a diagram showing speed fluctuations caused by an increase in the peripheral speed of the transport rollers at the moment when the document 7 is pulled out from between the transport rollers. The document 7 is conveyed by the reading inlet roller pair 17 and the reading outlet roller pair 18 via the first image reading sensor 29, but at the moment when the rear end of the document 7 in the conveying direction passes through the nip of the reading inlet roller pair 17. The roller diameter of the reading inlet roller pair 17 changes depending on the thickness of the document 7, the transport speed of the document 7 increases, and the image of the document 7 read by the second image reading sensor 19 is as shown in FIG. 8 (a). Image shrinkage 72 occurs. The shrinkage 72 of the image occurs from a position separated by a distance M with respect to the rear end in the transport direction of the document 7, and the distance M is the nip position of the reading inlet roller pair 17 as shown in FIG. 6, more accurately, the document 7. It corresponds to the distance between the position where the rear end passes through the nip of the reading inlet roller pair 17 and the image reading position of the document 7 by the first image reading sensor 29.

FIG. 7 is a schematic view of a main part of FIG. 2, which is a diagram showing speed fluctuations caused by resistance when the document 7 enters the nip of a pair of rollers. The document 7 is conveyed by the reading outlet roller pair 18, but the conveying speed of the document 7 is due to the resistance when the tip of the document 7 in the conveying direction passes through the second image reading sensor 19 and enters the nip of the outlet roller pair 20. As shown in FIG. 8B, the image of the document 7 read by the second image reading sensor 19 is stretched 73. The image elongation 73 is generated from a position separated by a distance N with respect to the tip of the document 7 in the transport direction, and the distance N is the image reading position of the document 7 by the second image reading sensor 19 and the exit roller as shown in FIG. It corresponds to the nip position of the pair 20, or more accurately, the distance between the tip of the document 7 and the position where the tip of the document 7 enters the nip of the exit roller vs. 20.

Further, as shown in FIG. 5, image elongation also occurs when the tip of the document 7 that exceeds the first image reading sensor 29 enters the nip of the reading outlet roller pair 18, and the transport speed of the document 7 is increased. As shown in FIG. 8A, the image of the document 7 which is reduced and read by the first image reading sensor 29 is stretched 74. The image elongation 74 occurs at a position separated from the tip of the document 7 in the transport direction by a distance J, and the distance J is the image reading position and the reading outlet of the document 7 by the first image reading sensor 29 as shown in FIG. It corresponds to the nip position of the roller vs. 18, or more accurately, the distance between the tip of the document 7 and the position where the tip of the document 7 enters the nip of the reading outlet roller vs. 18.

Further, as shown in FIG. 7, shrinkage of the image also occurs when the rear end of the document 7 whose image has been read by the second image reading sensor 19 passes through the nip of the reading outlet roller pair 18 and causes the document 7 to shrink. As shown in FIG. 8B, shrinkage 75 of the image occurs in the image of the document 7 read by the second image reading sensor 19 as the transport speed increases. The shrinkage 75 of the image occurs at a position separated from the rear end of the document 7 in the transport direction by a distance O. As shown in FIG. 7, the distance O is such that the rear end of the document 7 is the nip position of the reading outlet roller pair 18. More precisely, it corresponds to the distance between the position where the rear end of the document 7 passes through the nip of the reading outlet roller pair 18 and the image reading position of the document 7 by the second image reading sensor 19.

As described above, the deformation of the scanned image due to the fluctuation of the transport speed due to the transport path of the document 7, that is, the extension 71, 73, 74 of the image in the document 7 is based on the tip of the document 7, and the shrinkage 72, 75 of the image is It occurs at the same position each time with respect to the rear end of the document 7, that is, in a predetermined range from one end to the other end in the document transport direction.
In the present invention, the scanning operation is performed twice with the transport conditions of the document 7 changed so that the positions of the speed fluctuation occurrence points described above change with respect to the same document 7. That is, the image corresponding to the speed fluctuation occurrence location in the first reading operation is read in a state deviated from the speed fluctuation occurrence location in the second reading operation. In this way, the stretched or shrunk image corresponding to the speed fluctuation occurrence location at the time of the first reading is read by shifting from the speed fluctuation occurrence location at the second reading. Then, the location where the speed fluctuation occurs in the first time is replaced (complemented) with the second image read normally, and the two images are combined. When replacing (complementing), adjust the position from the reference. This makes it possible to form an image with a synthesized normal image (scanned image).
As described above, the location where the speed fluctuation occurs is determined by the predetermined arrangement positions of the plurality of members constituting the document transporting means of the roller pair for transporting the sensors 19 and 29 and the document 7 and the guide plate for guiding the transport. Therefore, the position where the image is stretched or shrunk is predetermined. Therefore, in the present invention, it is possible to delete a predetermined range of images that have been denatured and stretched or shrunk without detecting a defective image or comparing the scanned images twice. Moreover, since the image in a predetermined range is not used, it does not have to be read. Examples of the plurality of members in the present embodiment include a reading inlet roller pair 17, a reading outlet roller pair 18, and an outlet roller pair 20.

FIG. 9 shows an automatic document transfer device 76 according to still another modification of the embodiment of the present invention. The automatic document transfer device 76 is different from the automatic document transfer device 30 shown in FIG. 4 only in that it has a second image reading sensor 19, and other configurations are the same. In the automatic document transfer device 76, the document 7 whose image has been read by the first image reading sensor 29 is inverted and conveyed, and the conditions are changed with respect to the same document surface of the document 7 to read the image by the second image reading sensor 19. It is configured to be able to do.

The document image reading operation according to the first embodiment of the present invention using the automatic document transport device 76 shown in FIG. 9 will be described below.
10 (a), (b), (c), and (d) are all the same manuscript 7, and FIGS. 10 (a) and 10 (b) show the first surface image, that is, the surface image, and FIGS. 10 (c) and 10 (d) are shown. Indicates a second surface image, that is, a back surface image, and shows a state in which the front surface image is transparent. Alphabets A to Z are printed on the surface of the document 7.
FIG. 10A shows the document 7 set on the document table 32 viewed from above in FIG. The document 7 transported with the left end as the tip in FIG. 10 (a) is transported, and as shown in FIG. 10 (b) viewed from above in FIG. 9, the first image reading sensor is downward with the surface facing downward. The surface image is read by 29. In the first side image of the document 7 read at this time, as shown in FIG. 8A, the image extension 71 is at a position of a distance K from the tip, and the image extension 74 is at a position of a distance J from the tip. Image shrinkage 72 occurs at a position at a distance M from the rear end.

Subsequently, the document 7 whose surface image has been read by the first image reading sensor 29 is sent to the switchback transport path 66 for switchback transport. At this time, the reversing roller pair 68 is rotating clockwise in the clockwise direction, and the switching plate 67 occupies the position B. In the document 7 sent to the switchback transport path 66, after the rear end passes through the paper ejection roller pair 45 and advances a certain distance, the reversing roller pair 68 reverses in the counterclockwise direction and the switching plate 67 is positioned A. By being displaced to, it is sent to the reverse transport path 69. Further, the surface image of the document 7 read by the first image reading sensor 29 is stored in a storage unit provided inside the controller unit 60 at a distance from the tip end (left end portion in FIG. 10A). Remembered with.

The document 7 sent from the reversing transfer path 69 to the reversing roller pair 68 by the rotation of the paper ejection roller pair 45 is conveyed in the reversing transport path 69 by reversing the reversing roller pair 68. At this time, the document 7 has its surface facing down as shown in FIG. 10 (c) when viewed from above in FIG. 9, and is inverted from the initial state set in the document table 32 shown in FIG. 10 (a). There is. Then, with the left end in FIG. 10 (c) as the tip, the pull-out rollers are transported in the transport path 49 by the pair 13. The conveyed document 7 is inverted and sent to the second image reading sensor 19 via the reading inlet roller pair 17, the first image reading sensor 29, the reading outlet roller pair 18, and the transport path 50, and is upward in FIG. As shown in FIG. 10 (d) seen from the above, the surface image is read by the second image reading sensor 19 on the upper side with the surface facing up. In the first side image of the document 7 shown in FIG. 10 (d) read at this time, as shown in FIG. 8 (b), an extension 73 of the image is predetermined from the rear end at a position at a predetermined distance N from the front end. Shrinkage 75 of the image occurs at the position of the distance O.

In this way, the surface image of the same document surface is read twice by different transport paths under different transport conditions, and the image stretch 71, image stretch 74, and image shrink 72 that occur during the first scan. The positions of occurrence of the image are different from those of the image stretch 73 and the image shrink 75 that occur during the second reading. In order to improve the accuracy, each may be read a plurality of times and averaged.
The controller unit 60 (see FIG. 3) is an image of a predetermined portion specified in advance corresponding to the image stretch 71, the image stretch 74, and the image shrink 72 in the surface image of the document 7 read for the first time. Is specified by the distance from the tip and deleted, and the entire surface image is synthesized and stored by replenishing from the equivalent part of the surface image of the document 7 read a second time. As a result, one surface image without stretching or shrinking can be obtained.

As described above, according to the present invention, the controller unit 60 causes the sensors 19 and 29 to read the same image of the document 7 at least twice under different conditions, and the image processing unit 77 reads each image once. The controller unit 60 stores the image from the position information of the predetermined range corresponding to the expansion and contraction of one of the images stored in the image processing unit 77, and deletes the image of the predetermined range in the other image. It is complemented with the image of the above and stored as image data of the entire surface image of the original 7.
This makes it possible to suppress the occurrence of partial image expansion and contraction that occurs in image data due to speed fluctuations without performing the defect image detection process or comparing the scanned images twice. A transport device can be provided.

In the first embodiment, an example is shown in which an automatic document transport device 76 having a reverse transport mechanism including two sensors 19, 29, a pair of reverse rollers 68, a reverse transport path 69, and the like is used, which is shown in FIG. The present invention is also applicable to the automatic document transfer device 3 which does not have such a reverse transfer mechanism and the automatic document transfer device 30 which has only one sensor 29 as shown in FIG. In this case, the initial arrangement of the original 7 with respect to the original table 32 is different from each other, and the reading operation is performed twice. Of the one image, the image in a predetermined range corresponding to the expansion and contraction is deleted, and the other image is displayed. By complementing an image in a predetermined range with one image and storing it as image data of the document 7, it is possible to obtain the same effect as in the case of the automatic document transport device 76. Hereinafter, a second embodiment will be described.

11 (a), (b), (c), and (d) all show the same original 7, showing the first side image, that is, the front side image (left side) and the second side image, that is, the back side image, and the front side image is transparent. (Right side) is shown. Alphabets A to Z are printed on the surface of the document 7. That is, in each figure, the left side shows the state of the document 7 set on the document table 32, and the right side shows the state of the document 7 read by the sensor 19 or the sensor 29. Hereinafter, FIG. 11 (a) will be referred to as aspect a, FIG. 11 (b) will be referred to as aspect b, FIG. 11 (c) will be referred to as aspect c, and FIG. 11 (d) will be referred to as aspect d.
In aspects a and b, the printed surfaces are set facing upward, and the directions orthogonal to the conveying direction are arranged in opposite directions, and the ends in the conveying direction are different from each other. In aspects a and b, the surface image is read by the first image reading sensor 29.
In aspects c and d, the printed surfaces are set facing downward, and the directions orthogonal to the conveying direction are arranged in opposite directions, and the ends in the conveying direction are different from each other. In aspects a and b, the surface image is read by the second image reading sensor 19.

Since the transport directions of the document 7 are different from each other in the aspect a and the aspect b, even if the images are read by the same first image reading sensor 29, the locations where the expansion and contraction occur are different from each other. Further, since the transport directions of the document 7 are different from each other in the aspect c and the aspect d, even if the images are read by the same second image reading sensor 19, the locations where the expansion and contraction occur are different from each other.
Further, in aspects a and c, and aspects b and d, the front end side of the document 7 in the transport direction is the same and the front and back sides are opposite, but the sensors 19 and the sensor 29 are different from each other in reading the image. , The locations where the stretched and shrunk images are generated are different from each other.
After scanning the image, as in the first embodiment, the image of the portion corresponding to the expansion or contraction in the surface image of the document 7 scanned the first time is deleted, and the deleted image is scanned the document the second time. By replenishing and storing the surface image of No. 7 from the same location, the same effect as that of the first embodiment can be obtained.

In the second embodiment, the method of setting the original 7 on the original table 32 is changed between the first reading and the second reading, and the operation method is displayed on the operation unit 10 (see FIG. 3). May be. In this configuration, the operation unit 10 functions as a display device.
In a device such as the automatic document transporting device 30 shown in FIG. 4 which does not have the second image reading sensor 19, when the operation unit 10 displays the document setting method in aspect a and the document setting method in aspect b, the document 7 is displayed. On the other hand, it is possible to easily set documents having different transport directions.
Further, in a device having a second image reading sensor 19 such as the automatic document transporting device 3 shown in FIG. 2, two modes in which the speed fluctuation occurrence locations do not match may be selected and displayed from the modes a to d. .. Here, the first image reading sensor 29 and the second image reading sensor 19 often use different sensors or different characteristics from each other. When the same sensor is combined with the same original image to complement the image, the operation unit 10 may select and display the combination of the aspect a and the aspect b, or the aspect c and the aspect d. On the other hand, when complementing the same original image using different sensors, the four combinations of aspect a and aspect c, aspect a and aspect d, aspect b and aspect c, and aspect b and aspect d are used. The selection of may be displayed on the operation unit 10.
In any combination, the same original image is read twice under different transport conditions, and the speed fluctuation occurrence points are different from each other because the image reading conditions are different from each other. Therefore, as in the first embodiment, the read images can be complemented with each other to form one image without stretching or shrinking.

When forming one image by combining normal images without stretching or shrinking, a positional shift may occur at the boundary of positions that complement the images. For example, in the method of reading the original image by passing the first image reading sensor 29 twice, the skew amount differs between the first transfer and the second transfer. Therefore, when complementing the images read in the first and second times, skew correction and resist correction are performed so as to have an affinity at the boundary line portion and not cause a sense of discomfort.

FIG. 12 shows a third embodiment of the present invention. This third embodiment is different in that an image reading sensor 78 is used as an image reading means instead of the image pickup device 24 shown in FIG. 1, and the other configurations are the same.
The image reading sensor 78 includes an RGB sensor 78a which is a third image reading means and an RGB sensor 78b which is a fourth image reading means. The sensors 78a and 78b are arranged in parallel with each other and at different positions in the sub-scanning direction so that the same original image can be read at different timings, that is, at different reading positions. When the document 7 is read by the image reading sensor 78, the timing of reading the images on the same line is different from each other, so that the reading is started after delaying according to the difference in the positions of the sensors 78a and 78b in the sub-scanning direction. To. Further, the linear image sensors other than the RGB sensor can also be arranged at different positions in the sub-scanning direction so as to be parallel to each other, so that the timing of reading the image can be made different from each other.

When two images separated by a certain distance in the sub-scanning direction are read in one transfer as in the third embodiment, the skew amount and the resist amount are the same, and the image processing can be simplified. In addition, by setting the distance longer than the speed fluctuation occurrence location, different positions are read when the speed fluctuation occurs, so that the speed fluctuation occurrence locations in the original image are different from each other, and the speed fluctuation occurs. The work can be done efficiently and easily when synthesizing normal images.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, the roller pairs 17 and 18 are configured to be rotatable in the forward and reverse directions, and the operation of the roller pairs 17 and 18 having different distances from the reading position is controlled by the controller unit 60 (see FIG. 3). .. In the present embodiment, the document 7 is conveyed by the reading inlet roller pair 17 and the scanning outlet roller pair 18, the image reading by the first image reading sensor 29 is completed, and the rear end of the document 7 passes through the first image reading sensor 29. After that, the reading outlet roller pair 18 and the reading inlet roller pair 17 are inverted while being sandwiched between the reading outlet roller pair 18. Then, the transport direction is reversed so that the document 7 is read again by the first image reading sensor 29.
With this configuration, original images read in different transport directions can be complemented with each other to form one image without expansion or contraction. In the fourth embodiment, the reading inlet roller pair 17 and the reading outlet roller pair 18 constitute the reverse feed means.

In the fourth embodiment, the configuration in which the surface image is read by the first image reading sensor 29 is shown, but the second image reading is performed like the automatic document conveying device 3 shown in FIG. 2 and the automatic document conveying device 76 shown in FIG. In the case of the configuration having the sensor 19, in addition to the above-mentioned reading of the front surface image, the back surface image can be read by the second image reading sensor 19. Hereinafter, a modified example of the fourth embodiment will be described with reference to FIG. 7.
In the automatic document transfer device 3 shown in FIG. 2, when the second image reading sensor 19 performs two image readings by reverse feeding, the rollers 18 and 20 having different distances from the reading position are rotated in the forward and reverse directions, respectively. The operation of each roller pair 18 and 20 is controlled by the controller unit 60 so as to be possible. In the present embodiment, the document 7 is conveyed by the reading outlet roller pair 18 and the outlet roller pair 20, the image reading by the second image reading sensor 19 is completed, and the rear end of the document 7 has passed through the second image reading sensor 19. After that, the outlet roller pair 20 and the reading outlet roller pair 18 are inverted while being sandwiched between the outlet roller pair 20. Then, the transport direction is reversed so that the document 7 is read again by the second image reading sensor 19.

In the automatic document transfer device 76 shown in FIG. 9, when the second image reading sensor 19 performs two image readings by reverse feeding, the roller pairs 18 and 45 having different distances from the reading position are rotated in the forward and reverse directions, respectively. It is configured to be possible, and the operation of each roller pair 18, 45 is controlled by the controller unit 60. In the present embodiment, the document 7 is conveyed by the reading outlet roller pair 18 and the paper ejection roller pair 45, the image reading by the second image reading sensor 19 is completed, and the rear end of the document 7 passes through the second image reading sensor 19. After that, the paper ejection roller pair 45 and the reading outlet roller pair 18 are inverted while being sandwiched between the paper ejection rollers vs. 45. Then, the transport direction is reversed so that the document 7 is read again by the second image reading sensor 19.
In the modified example of the fourth embodiment, documents read in different transport directions can be complemented with each other to form one image without stretching or shrinking. In this modification, the back feed means is configured by the reading outlet roller pair 18 and the outlet roller pair 20 in the configuration shown in FIG. 2, and by the reading outlet roller pair 18 and the paper ejection roller pair 45 in the configuration shown in FIG.

In the fourth embodiment, as shown in FIGS. 5 and 6, the distance M to the reading inlet roller pair 17 and the distance J to the reading exit roller pair 18 are different from each other with respect to the first image reading sensor 29. The arrangement of each roller pair 17 and 18 is asymmetric with respect to the first image reading sensor 29. If the document 7 can be conveyed from both the left and the right and the roller configuration is symmetrical with respect to the first image reading sensor 29, the speed fluctuation occurrence points with respect to the document 7 will be at the same position during reciprocation. However, by arranging the transport members asymmetrically with respect to the first image reading sensor 29 as in the present embodiment, the speed fluctuation occurrence points with respect to the document 7 can be set to different positions during reciprocation, and different transports can be made. Documents read in directions can be complemented with each other to form a single image without stretching or shrinking.
In the fourth embodiment and the modified example, the reading inlet roller pair 17 and the first image reading sensor 29, the reading outlet roller pair 18 and the first image reading sensor 29, the reading outlet roller pair 18 and the second image reading sensor 19, the outlet. The relationship between the roller 20 and the second image reading sensor 19, and the paper ejection roller pair 45 and the second image reading sensor 19 has been described. However, the first image reading sensor 29 and the guide plate 70 on the downstream side of the first image reading sensor 29 have been described. The same applies to the relationship between the end portion of the guide plate 70 and the end portion of the guide plate 70 on the upstream side.

FIG. 13 shows a fifth embodiment of the present invention. Compared with the configuration shown in FIG. 5, this fifth embodiment bulges an immovable lower guide member that constitutes a transport path 79 between the first image reading sensor 29 and the downstream reading outlet roller pair 18. However, the difference is only in that the guide plate 80 as the range variable member constituting the document transporting means is arranged in the bulging portion, and the other configurations are the same.
One end of the guide plate 80 is supported by an immovable upper guide member constituting the transport path 79, and the guide plate 80 is configured to swing around this one end. The guide plate 80 is a member that is swung by an actuator such as a solenoid or a motor (not shown) by the controller unit 60 (see FIG. 3). The guide plate 80 is configured to be able to arbitrarily occupy a position between the position shown by the solid line and the position shown by the broken line in FIG. With this configuration, the guide plate 80 becomes a range-variable member capable of changing the document length of the distance J between the first image reading sensor 29 and the reading outlet roller pair 18, and arbitrarily changes the speed fluctuation occurrence location of the document 7. be able to.
According to the fifth embodiment, in the manuscript 7 of various sizes including irregular shapes, the speed fluctuation occurrence location can be changed for each reading operation, and the manuscripts read under different transport conditions are complemented with each other. You can easily form one image without stretching or shrinking.

In the above-described embodiment and each modification, an example in which the image forming apparatus of the full-color copying apparatus 1 in which the automatic document scanning apparatus is integrated is used is shown, but images of a printer, a facsimile, a multifunction device, such a monochrome machine, and the like are shown. The present invention can also be applied to an automatic document reading device such as a scanner that is separate from the forming device. Further, in each embodiment, the configuration in which the manuscript 7 is used is shown, but the manuscript 7 includes thick paper, postcards, envelopes, plain paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and OHP sheet. , OHP film, resin film and the like are also included, and any material may be used as long as it is in the form of a sheet and can be transported.
Further, in each embodiment, the configuration in which the transfer sheet S is used as the recording medium on which the image is formed is shown, but the transfer sheet S includes thick paper, postcards, envelopes, plain paper, thin paper, and coated paper (coated paper or Art paper, etc.), tracing paper, transparencies, transparencies, resin films, etc. are also included, and any material may be used as long as it is in the form of a sheet and can form an image.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and unless otherwise specified in the above description, the present invention described in the claims. Various modifications and changes are possible within the scope of the purpose.
The effects described in the embodiments of the present invention merely exemplify the most preferable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not it.

1 Image forming device (copying device)
3,30,76 Automatic document transfer device 5 Image forming unit 6 Automatic document reader 7 Document 10 Display device (operation unit)
17 Roller pair (reading inlet roller pair)
18 roller pair (reading outlet roller pair)
19 Reading member, second image reading member (second image reading sensor)
20 roller pair (exit roller pair)
29 Reading member, first image reading member (first image reading sensor)
77 Image processing unit 78a Third image reading member (RGB sensor)
78b Fourth image reading member (RGB sensor)
80 Range variable member (guide plate)

Japanese Unexamined Patent Publication No. 2010-226361

Claims (9)

A pair of rollers that convey the document,
A reading member for reading an image of a document conveyed by the roller pair is provided.
The same image is read a plurality of times together with position information by the reading member under different conditions, an image in a predetermined range set in advance is deleted from one image, and another image different from the one image is used. An automatic document scanning device that complements an image in the predetermined range with the one image to obtain image data of the document. In the automatic document reader according to claim 1,
An automatic document reading device having a plurality of roller pairs, wherein the predetermined range is determined based on the arrangement of the plurality of roller pairs and the reading member. In the automatic document reader according to claim 2,
The reading member has a first image reading member for reading the front surface image of the document and a second image reading member for reading the back surface image of the document, and the roller pair reads the front and back of the document whose image is read by the reading member. An automatic document reading device characterized in that it is inverted and conveyed again toward the reading member. In the automatic document reader according to claim 2,
In addition to having a display device, the reading member has a first image reading member for reading the front surface image of the document and a second image reading member for reading the back surface image of the document, so that the document can be read under different conditions. An automatic document reading device characterized by displaying on the display device. In the automatic document reader according to claim 2,
The reading member is a third image reading member that reads an image of one side of the document, and a fourth image that is arranged at a predetermined distance from the third image reading member and reads an image of one side of the document. An automatic document reading device characterized by having a reading member. In the automatic document reader according to claim 2,
The roller pair is an automatic document reading device characterized in that a document whose image has been read by the reading member is back-fed toward the reading member. In the automatic document reader according to claim 6,
An automatic document reading device characterized in that the plurality of roller pairs are arranged at positions asymmetric with respect to the reading member in the document transport direction. In the automatic document reader according to claim 2,
An automatic document reading device comprising a range-variable member that changes the predetermined range. An image forming apparatus comprising the automatic document reading apparatus according to claim 1 to 8 and an image forming unit that forms an image.

Images