JPH0834542A - Document conveying device for image reading device - Google Patents

Abstract

PURPOSE:To prevent a document from being applied with excess tension and prevent the read information from being compressed even when the conveying speed differs between a roller device arranged on a document tray side and the roller device of a scanning section conveying device when the document is scanned while being conveyed by a document conveying device. CONSTITUTION:A scanning section conveying device 20 is arranged on a document conveying device 10 to face a platen 2 provided on an image reading device 1. A document fed from a document tray 11 by a paper feeder 12 is registered while its tip section collides with the registration roller device 21 of the scanning section conveying device 20, then it is conveyed at a scanning section by the roller device of the scanning section conveying device 20. The document is formed with a loop on a document conveyance path 25, the loop of the document is reduced while the document is conveyed by the scanning section conveying device, and two rocking guide plates 28, 29 of an inside guide member 27 are rocked to the inside not to apply excess tension to the document.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder for an image reading apparatus, and more particularly, it scans a document aligned by forming a loop on the document in a document feeding path arranged upstream of a scanning section feeding device. A document transport device for an image reading apparatus, which can prevent the velocity of a document from changing under the influence of transport by a roller device disposed in an upstream portion of a document transport path when scanning while transporting by the document transport device. Regarding

[0002]

2. Description of the Related Art In an image forming apparatus such as a facsimile machine or an electrophotographic copying machine, an image reading device is arranged at the upper part of the main body of the apparatus, and an original set on an original tray is read by one.
A unit is provided for reading out an image while feeding the sheets one by one toward the scanning unit and transporting them at a constant speed by the scanning unit transporting device at a position corresponding to the scanning device. For example, JP-A-4-
In the image reading device disclosed in Japanese Patent No. 358139, etc.,
The scanning section conveying device is arranged corresponding to the platen on which the scanning apparatus is arranged, and the scanning section conveying device is constituted by a platen roller corresponding to the platen and a conveying roller device arranged upstream and downstream thereof. Then, while driving the conveying roller device arranged on the upstream and downstream of the platen at a constant speed,
A scanning device located below the platen constitutes a unit for reading an image of a document.

Apart from the above-mentioned conventional example, JP-A-5-3362
In the example disclosed in Japanese Patent Publication No. 86, etc., a document is placed on a large platen with respect to a digital image reading apparatus, and a reading unit is provided in a state where the document is fixed while moving the scanning device. There is. In addition to the large platen, the scanning unit transport device is arranged for the small platen,
A device capable of scanning while moving a document while the scanning device is held at a fixed position is integrally provided, and two types of scanning devices are provided for one image reading device. In the image reading apparatus of the conventional example, when the original is a sheet, the original is fed from the original tray one by one, and a scanning unit conveying device is used to scan the original while feeding the original. When the book is thick like a book, a means for scanning while moving the scanning device can be used.

As described above, a device for reading a moving original with the scanning device arranged at a fixed position is a very widely used device, for example, it is arranged in the transmission section of a facsimile machine. A commonly used document feeder is configured as shown in FIG. 7, for example. In the document transporting device shown in FIG. 7, in the scanning unit transporting device 20a corresponding to the scanning unit, the platen roller 22 is arranged corresponding to the platen 2, and the registration roller device 21 is discharged upstream and the registration roller device 21 is discharged downstream. The rollers 23 are arranged respectively, and the original is conveyed while being slid on the platen by the platen roller while driving the conveying roller device arranged at the upstream and downstream parts of the platen roller 22 at a constant speed. Then, the image of the original is irradiated by the scanning device 5 which is stopped at a fixed position below the platen 2, and the reflected light is incident on the lens 8 through the plurality of mirrors m1 to m3, and photoelectric conversion such as CCD is performed. An image is formed on the means and output from the CCD as a digital signal.

Further, an original tray and a paper separating device 12a are arranged upstream of the scanning section conveying device 20a. In the paper separating device, the originals are separated one by one by a feed belt 17 and a retard roller 18. It constitutes the means for sending out. The scanning unit transport device 20a
Then, it is possible to configure a means for aligning the document D sent from the document tray between the sheet separating device 12a and the registration roller device 21, and in the state where the leading end of the document is projected into the registration roller device, An extra feeding action is given by the sheet separating device so that the document aligning action is performed. Therefore, in the case of configuring the sheet aligning apparatus as described above, the original aligned in the upstream portion of the scanning unit transporting device is transported at a constant speed by the transporting roller device of the scanning unit transporting device so that the scanning unit transports the document. Accurate image information can be obtained by preventing the output image information from being distorted.

[0006]

However, in the document conveying apparatus as shown in FIG. 7, the state in which the document is conveyed by both the sheet separating device and the conveying roller device of the scanning section conveying device and the sheet separating device. There is a problem that the moving speed of the document changes when the trailing edge of the device is pulled out. For example, as shown in the graph of FIG. 8, when a document is being conveyed by both the conveyance roller device of the scanning unit conveyance device and the sheet separating device, conveyance resistance is imparted by the sheet separating device. , The transport speed of the scanning unit transport device is slowed by the resistance of the paper sorting device,
The magnification of the read image becomes 100% or more. On the other hand, when the trailing edge of the document is pulled out from the paper sorting device, the resistance of the paper sorting device disappears,
The transport speed of only the transport roller device of the scanning transport device is slightly higher than the set value. The image information output from the image reading device tends to be locally shortened, and slips or the like in the transport roller device of the scanning unit transport device causes scan information of the document output from the image reading device. There is a problem that it has a great influence on.

The above-mentioned problem occurs when the conveying roller device of the scanning portion conveying device is set in consideration of the resistance value of the sheet separating device so that the document conveying speed in the scanning portion can be kept constant. In practice, the difference in speed variation of the document is about several percent, so that it is not a big problem in a facsimile machine or the like. However, when the image reading device as shown in FIG. 7 is incorporated in an electrophotographic copying machine or the like to make an enlarged copy, a relatively small change in the enlargement / reduction ratio has a great influence on the image quality of the copy. It leads to the problem of giving. Therefore, in order to solve the above-mentioned problem, if the distance between the sheet separating device and the transport roller device at the upstream portion of the scanning unit transport device is set to be longer than the maximum size of the document, the document is distributed between the rollers of the transport device. The problem of inquiries will not occur.
However, in order to achieve an object such as downsizing of the configuration of the image reading apparatus, it is difficult to configure the document transport path to be long, and after aligning the documents, the document is transported in the long document transport path. Doing so also causes the document to be obliquely fed during scanning.

Further, in a digital type electrophotographic copying machine or the like, a document feeding speed in an image reading device is set to a high speed, and a document feeding device arranged on a document tray and a feeding roller device of a scanning portion feeding device are provided. Therefore, a means for forming a loop on a document to perform a matching action is provided. In the image reading device, a matching action is imparted in a state where a loop is formed on a document sent from a document tray,
When the document is conveyed toward the scanning section conveying device, the conveying operation is performed by the conveying roller device and the sheet separating device at the upstream portion of the loop of the document, and the scanning section conveying device performs the conveying operation at a constant speed. However, in the roller device that performs the conveying action on the front and rear portions of the document, the problem that the resistance of the downstream conveying roller device such as the paper separating device is added to the speed of the downstream conveying roller device is solved. Difficult to do.

Therefore, in order to solve the above-mentioned problem, for example, as shown in Japanese Patent Laid-Open No. 62-244846, the leading end portion of the paper is locked to a registration roller device or the like, and the paper is fixed. It is conceivable to use a means for forming a loop and gradually reducing the loop of the sheet during the constant speed conveyance by the registration roller device. However, the use of the above-described transport method for the paper transport path is set in a state where the difference in transport speed between the roller devices is relatively small, and the comparison is also made from the nip value of the transport roller device. Since the size is set to be relatively large, expansion and contraction of the image at the transfer portion or the like is unlikely to occur even when the sheets are conveyed while being pulled. However, the use of the loop forming method as shown in the conventional example and the conveying device in the state of pulling the originals with respect to the original conveying path cannot be easily applied due to problems such as different kinds of originals. There is a problem.

[0010]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional document feeder as described above, and the document feed path disposed between the document tray and the scanning section feed device is constructed as a curved path, so that (EN) Provided is a device that forms a loop along a document transport path to provide a matching action, and then does not fluctuate the transport speed in the scanning unit when performing scanning while transporting by the scanning unit transport device. Further, an object of the present invention is to provide an original document conveying device for an image reading apparatus in which the speed of the scanning portion does not fluctuate by reducing the loop of the original document even when the upstream conveying roller device is at a constant speed. Has an aim.

[0011]

According to the present invention, a scanning device is arranged at a fixed position so as to correspond to a platen, and means for scanning an image of a document moving at a constant speed is constituted, and the scanning device is arranged at a position corresponding to the platen. A platen roller is arranged, a conveying roller device is arranged on the upstream and downstream parts of the platen roller to form a scanning unit conveying device, and a unit for conveying an original at a constant speed by the scanning unit conveying device is formed. The originals placed on the sheet are sent one by one toward the original conveying path through the paper feeding device, and the originals are aligned between the conveying roller device arranged in the original conveying path and the roller device upstream of the platen roller. The present invention relates to a document feeding device that performs an image reading while feeding a document by a scanning unit feeding device. In the present invention, the document transport path is configured as a curved path, a means for performing an aligning action on a document in a state of being curved in the document transport path is configured, and an outer guide member for partitioning the document transport path is arranged. An inner guide member corresponding to the outer guide member is swingably provided, and when a document aligned in the document transport path is transported by the scanning unit transport device, the inner loop is made to follow an operation in which the loop of the document becomes smaller. Swing the guide member.

Further, in the present invention, the inner guide member arranged in the original conveying path is a combination of two rocking guide plates, and when the leading end portions of the two guide plates are brought into contact with each other, the A drive means is provided which supports the end portion through a support shaft and swings the two guide plates in conjunction with each other.
It is possible to configure a driving means for swinging the guide plate in synchronism with the driving of the roller device of the scanning section transport device. Further, in the present invention, the inner guide member arranged in the document conveying path is composed of two guide plates, and the two guide plates are provided so as to be swingable in a state where the tip end portions of the two guide plates are in contact with each other, and It is also possible to provide swing means for swinging the two guide plates by the pressure of the original.

[0013]

In the apparatus of the present invention configured as described above, the original sent from the original tray is conveyed along the curved original conveying path, and the leading end of the original is projected to the registration roller device of the scanning conveying device. When applied, a loop is formed to provide a matching action. Then, when the image is read using the scanning device while being conveyed by the scanning unit conveying device, even if the conveying speed of the trailing edge of the document is affected by a device such as a paper separating device, the conveying speed of the scanning unit conveying device Therefore, the document can be moved at a constant speed with respect to the scanning device so as not to affect the scanning. Therefore, in the document feeder of the present invention, a swing guide plate is arranged on the inner guide member with respect to the document feeding path configured as a curved path so that the leading edge of the document is fast and the trailing edge is slow. Even when the sheet is conveyed, the operation of swinging the guide plate allows the sheet to be conveyed while allowing the action of reducing the loop of the sheet. Therefore, even if the front and rear of the document are attracted by a transport roller device or the like having different speeds, the speed difference is dealt with by changing the shape of the loop, and the speed of the document at the scanning unit is prevented from changing. It can be so. Further, in the inner guide member of the present invention, the swing guide plate is driven according to the document transport operation in the scanning section transport device, or the swing guide plate is swung by the pressure of the document. It is possible to configure the means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A document feeder for an image reading apparatus according to the present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows a configuration of a document feeding device and a scanning device of the present invention. A small platen 2 is arranged on the image reading device 1 so as to correspond to a position for scanning while moving a document.
And a large platen 3 on which a document such as a book is placed. Scanning device 5 for the two platens
The scanning device holds the fixed state at a position corresponding to the platen 2 so that the image of the moving original is read. When scanning is performed corresponding to the other platen 3, the scanning device is moved along the lower surface of the platen so that the image of the document set at the fixed position can be scanned. In the scanning device 5, the lamp 6 and the reflecting plate 7 are arranged so as to face each other, the light of the lamp 6 is focused on the original by the reflecting plate 7 and is irradiated, and the reflected light is reflected through the plurality of mirrors m1 to m3. Then, a means for transmitting the light imaged by the lens 8 to the CCD 9 and outputting it as a digital signal is constituted.

The document feeding device 10 arranged above the image reading device 1 is provided with a document tray 11 on which a sheet-like document is placed and a paper feeding device 12 arranged at a document feeding portion of the document tray 11 above. ing. Then, the original is taken out by the pickup roller 13 which constitutes the paper feeding device, and a separating operation is performed between the paper feeding roller 14 and the retard pad 15. A conveying roller device 16 is arranged downstream of the paper feeding device 12, and a document conveying path 25 is provided.
A document is fed toward the document, and the document is conveyed in a regulated state between the outer guide member 26 and the inner guide member 27 inside the document conveyance path 25 formed as a curved path. In addition, the scanning section conveying device 2 is provided at the lower end of the original conveying path 25.
0 is arranged, and the scanning unit transport device 20 includes a platen roller 22 corresponding to the platen 2, an upstream registration roller device 21, and a downstream discharge roller 23. Further, a discharge tray 24 is arranged downstream of the scanning section transporting device 20 so as to accommodate the scanned document.

The document conveying path 25 includes an outer guide member 26 arranged at a fixed position and an inner guide member 27 arranged inside the outer guide member 26 with two swing guide plates 28 and 29. Of the two rocking guide plates, the rocking guide plate 28 on the upstream side has its upstream end supported by the support shaft 38, and the end on the downstream side contacts and separates from the outer guide member 26. Place in a state. Further, the swing guide plate 29 arranged on the downstream side of the inner guide member is swingably provided via a support shaft 39 provided on the downstream end,
The upstream end of the rocking guide plate 29 performs a rocking motion for each rocking guide plate while being positioned inside the arc with respect to the tip of the upper rocking guide plate 28. To do so.

The document feeder 10 configured as described above
In FIG. 3, the original taken out from the original tray 11 is conveyed in the original conveying path 25 by the conveying roller device 16 arranged on the upstream side of the original conveying path, and the leading end portion thereof is a nip of the registration roller device 21 of the scanning conveying device 20. Make sure that the matching action is performed with the part rushing in. When performing the sheet aligning action in the document transport path 25, after the leading edge of the document is detected by the sensor S1, the action of sending the document is started in synchronization with the operation of the scanning section transport device. 21 is in a stopped state. After the leading edge of the original is detected by the sensor S1, the operation of feeding the original for a predetermined time is performed, so that the leading edge of the original enters the nip position of the registration roller device 21 and then the feeding roller device is operated. An additional feed action is provided by 16 to form a loop in the document. Then, by the reaction force of the loop of the original document, the leading end of the original document is uniformly inserted into the nip position of the registration roller device 21 to perform the matching action, and the scanning section conveying device is operated in synchronization with the operation timing of the scanning device. Each roller device is driven so that the original document is conveyed at a constant speed.

The inner guide member arranged in the document conveying path of the present invention is constituted by the swing guide plate, so that the conveying roller device 16 and the scanning section are formed in the state where a loop is formed in the document inside the document conveying path 25. This is because the registration roller device 21 and the discharge roller 23 of the transport device 20 can be driven to prevent excessive tension from being applied to the document when the document is transported at the scanning position. . That is, when a document is transported in the document transport path 25, the roller device of the scanning unit transport device that is transported at a constant speed is
When the speeds of the sheet separating device and the conveying roller device 16 at the upstream portion are low, the loop formed on the original inside the original conveying path is gradually reduced. Therefore,
If the action that reduces the loop of the original is given,
The document is strongly pressed against the inner guide member, the frictional force between the document and the inner guide member increases, and there is concern that the action of constant-speed conveyance of the document may be hindered.

In order to solve the above-mentioned problems, in the present invention, as shown in FIG. 2, the inner guide member is composed of two rocking guide plates 28 and 29, and each rocking guide plate. In order to perform the swinging with respect to, the driving device 30 is arranged so that the length of the path for guiding the document by the inner guide member can be adjusted. FIG. 2
In the inner guide member 27 and the driving device 30 shown in FIG. 2, the two rocking guide plates 28 and 29 forming the inner guide member 27 are the upper ends of the lower rocking guide plates 29 at the portions where the respective guide plates are aligned. The parts are overlapped with each other inside the arc. Further, half-moon gears 35 and 36 are respectively arranged on the support shafts 38 and 39 supporting the two guide plates, and the drive gear 32 and the intermediate gear 33 of the motor 31 are connected to the half-moon gears 35 and 36. , Are arranged so that they mesh with each other in the illustrated state.

In the drive device 30, the drive information input to the motor 31 can be output in synchronization with the drive information for the registration roller device 21 of the scanning section transport device 20. For example, when the document transport device carries out the document transport operation, the drive mode for the motor 31 is set in accordance with the information about the tension applied to the document by the transport roller devices located upstream and downstream of the document transport path 25. The swinging operation of the inner guide member with respect to the swing guide plates 28, 29 can be performed according to the degree of reduction of the loop of the document. Therefore, the document transport path 2
Control is performed such that the guide distance of the document by the inner guide member is gradually reduced according to the difference between the transport speed of the transport roller device 16 in the upstream portion of No. 5 and the transport speed of the registration roller device of the scanning transport device. be able to.

In the document feeding apparatus having the above-described structure, the document feeding operation can be performed as shown in the timing chart of FIG. In the timing chart of FIG. 3, the leading edge of the document is fed by the paper feeding device, and the paper feeding by the paper feeding device is
When the carrying action of the carrying roller device 16 is started, the sensor S
It ends when it is detected by 1. Then, after that, the conveying operation is continued by the conveying roller device 16, the leading edge of the document is detected by the sensor S2, and after reaching the nip position of the registration roller device 21, an extra drive is performed for a predetermined time t1. , Stops when a loop is formed on the document. At that time, a loop having a predetermined size is formed on the document, and the loop is formed along the outer guide member 26 of the document transport path 25.

As described above, after the document aligning operation is performed, the registration roller device 21 of the scanning section conveying device 20 is synchronized with the operation of the scanning device.
Is driven, the original is passed through the reading position by the platen 2, and the operation of scanning the image of the original is started. Before the operation of starting the conveyance of the document, the two swing guide plates 2 of the inner guide member 27 are provided in the document conveying device.
When the registration roller device 21 conveys the document toward the scanning unit after starting the operation of swinging the inner parts 8 and 29 inward, the inner guide member corresponds to the action of feeding the document in a state where the loop of the document becomes small. Do not slide on the document. Further, when starting the operation of sending the document toward the scanning section by the registration roller device 21, the transport roller device 16 arranged upstream of the document transport path.
To prevent the resistance of the retard pad of the sheet feeding device from affecting the speed of the document conveyed by the roller device of the scanning section conveying device.

As described above, at the scanning section corresponding to the platen 2, while the original is being conveyed by the scanning section conveying device 20, the rear end of the original leaves the nip position of the conveying roller device 16, When the information detected by the sensor S1 is obtained, the driving of the transport roller device is stopped. At the same time, the two swing guide plates 28, 29 of the inner guide member 27 are returned to their original positions. However, even if the swing guide plates are returned to their original positions, the trailing edge of the document remains free. Since the document is in the state, even if the document is slid on the inner guide member in a state where no tension is applied to the document, the document transport operation of the scanning section transport device is not affected. Then, after a lapse of a predetermined time from the detection of the trailing edge of the original by the sensor S2, the driving of the scanning unit transport device 20 to the roller device is stopped, but the driving of the scanning unit transport device is stopped.
After the detection information of the sensor S2 is input, the setting is performed according to the time set by a timer or the like, and the setting is set according to the timing when the document passes through the discharge roller 23 at the downstream portion of the scanning unit transport device.

[0024]

[Embodiment 2] In addition to using the document guiding means as shown in FIG. 1, in the present invention, it is also possible to construct a document conveying path as shown in each of FIGS. Is. In the document transport path 25a shown in FIG. 4, the outer guide member 26 is arranged at a fixed position, but the swing guide plates 41 and 45 that form the inner guide member 40.
Has a spring 4 without a motor drive.
A swinging mechanism composed of 3, 47 is provided. Further, the swing guide plates 41 and 45 are swingably provided via the respective support shafts 42 and 46, and are made to follow the operation in which the loop formed in the document becomes smaller, and are guided by the pressing force of the document. The plate is swung inward so that the sliding resistance of the guide plate with respect to the document does not increase.

Therefore, in the document conveying path 25a shown in FIG. 4, a loop is first formed in the document to perform the document aligning operation, and then the document is conveyed by the scanning section conveying device while being scanned. Following the operation of reducing the shape of the loop of the document, the inner guide path of the document by the inner guide member 40 is reduced, and the document is conveyed by the scanning unit while the resistance to the document is small. You can Then, the rear end portion of the document is the conveyance roller device 1
Since the pressing force of the document against the inner guide member is released in a state where the nip position of 6 is removed, the two rocking guide plates 41, 45 constituting the inner guide member 40 are
It is returned to its original position by the force of the spring so that it can deal with the next document to be sent.

In the example shown in FIG. 5, the document conveying path 25b
The inner guide member 50 inside the outer guide member 26 arranged in
And means for reducing the loop of the original document against the elasticity of the film member 51. Further, a fixed guide 52 is arranged inside the film member 51 as the inner guide member to set a limit for reducing the loop of the document. However, in the operation of conveying the document in a normal state, The document is arranged at a position where it does not slide on the fixed guide 52. By constructing the document transport path 25b as shown in FIG. 5, in this embodiment, the document delivered from the document tray 11 by using the sheet feeding device 12 is transported by the transport roller device in the document transport path 25b. 1
6 is conveyed. Then, the leading end portion of the original is stopped in a state of abutting against the nip position of the registration roller device 21 of the scanning unit transport device 20, and a loop is formed along the outer guide member 26, and the leading end portion of the original document is set to the registration roller. The document is pressed against the nip portion of the device 21 with a uniform force to align the document. After that, by driving the scanning section transporting device 20 in accordance with the operation of the scanning device, an image is read by the scanning device while the document is transported on the platen 2 at a constant speed.

As described above, while the document is being conveyed in the scanning section, the document conveyance speed between the conveyance roller device 16 and the roller devices of the registration roller device 21 is different, so that the document loop is formed. Occurs so that the value becomes smaller. Since the film member 51 forming the inner guide member is pressed by the document and curved inward due to the contraction action of the loop of the document, the frictional action between the film and the document is not a large value. No
The frictional force with the film does not affect the document transporting action. Further, in the embodiment shown in FIG. 5, as the film member, for example, a thin film member made of elastic plastic such as Mylar (trade name) can be used. It is possible to use a plastic film member having a relatively small frictional force with the film member, and use an arbitrary means such as attaching the upstream end of the film member to the fixed guide 52 of the inner guide member. It can be attached and used.

In addition to the embodiment shown in FIG. 5, the original document feeding apparatus of the present invention may have an original document feeding path 25c as shown in FIG. The document transport path 25c
In, the inner guide member 55 is arranged inside the outer guide member 26 with a large gap, and the inner guide member 55 is provided at a fixed position. Then, in a state where the original is pressed against the inner surface of the outer guide member 26 of the original conveying path 25c, a loop Dr is formed in the original to perform the original aligning operation, and thereafter, the roller device of the scanning portion conveying device 20 is driven. Meanwhile, the document is conveyed and scanned. When the document loop gradually becomes smaller during the scanning of the document, the document loop Dr is separated from the outer guide member as illustrated as a loop Dr1 and approaches the inner guide member 55. However, general A3
For a document of a size or less, even if the loop of the document becomes small during scanning, the document is prevented from sliding on the inner guide member 55. Therefore, the smallest loop Dr1 of the document is the inner guide member. The transport action corresponding to the scanning is performed in a state away from 55.

In the document conveying path shown in each of the embodiments of the present invention, the registration roller device 21 arranged upstream of the scanning portion conveying device 20 is used as a constant speed conveying roller device having no registration performance. In that case, in this case, a registration gate or the like may be provided in the upstream portion of the registration roller device 21 to constitute a means for aligning the leading end portion of the document. The means for moving the guide surface of the inner guide member inward is provided in response to the fact that the original aligned in the original conveying path is conveyed by the scanning portion conveying device and the loop becomes smaller. In addition to each embodiment, an arbitrary swing guide plate or the like can be used. Further, even when the inner guide member is arranged at a position largely separated from the outer guide member in correspondence with the document conveying path and the inner guide member is configured not to slide with respect to the document loop, the document loop Even when the size is reduced to the minimum, the document can be conveyed without sliding on the inner guide member. Furthermore, the document feeder of the present invention is not limited to the document feeder shown in FIG. 1, but can be incorporated in any automatic document feeder.

[0030]

Since the document feeder of the image reading apparatus of the present invention is configured as described above, the document fed from the document tray is fed along the curved document feeding path, In the state where the leading end of the document is abutted against the registration roller device of the scanning section transporting device, the action of forming a loop and providing the aligning action can be exhibited well. Then, when the image is read using the scanning device while being conveyed by the scanning unit conveying device, even if the conveying speed of the trailing edge of the document is affected by a device such as a paper separating device, the conveying speed of the scanning unit conveying device It is possible to move the document at a constant speed with respect to the scanning device, without affecting the above. Therefore, since it is possible to prevent the document conveyance speed from changing during scanning, it is possible to prevent the scan information of the document from being reduced or enlarged and to output clear scan information.

In order to achieve the above-mentioned object, in the document conveying apparatus of the present invention, the swing guide plate is arranged on the inner guide member with respect to the document conveying path formed as a curved path, and the leading end of the document is arranged. Even when the sheet is conveyed at a high speed and the trailing edge is conveyed at a low speed, it is possible to use means for conveying the sheet while allowing the action of reducing the loop of the sheet by the action of swinging the guide plate. Therefore, even if the front and rear of the document are attracted by a transport roller device or the like having different speeds, the speed difference is dealt with by changing the shape of the loop, and the speed of the document at the scanning unit is prevented from changing. it can. Further, in the inner guide member of the present invention, the swing guide plate is driven according to the document transport operation in the scanning section transport device, or the swing guide plate is swung by the pressure of the document. It is possible to configure the means.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a document feeder of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an inner guide member of FIG.

FIG. 3 is a timing chart showing a document feeding operation by the document feeding apparatus of FIG.

FIG. 4 is an explanatory diagram of a second embodiment of the document feeder of the present invention.

FIG. 5 is an explanatory diagram of a third embodiment of the document feeder of the present invention.

FIG. 6 is an explanatory diagram of a fourth embodiment of the document feeder according to the present invention.

FIG. 7 is an explanatory diagram showing a configuration of a conventional document feeder.

8 is a graph showing a problem of scanning information in the document feeder of FIG.

[Explanation of symbols]

1 image reading device, 2.3 platen, 5
Scanning device, 10 document transport device, 11 document tray, 12 sheet feeding device, 16 transport roller device, 20 scanning unit transport device, 21 registration roller device, 22 platen roller, 23 discharge roller, 25 document transport path, 26 outer guide member , 27 inner guide member, 28/29 swing guide plate, 30 drive device, 40/50/55 inner guide member.

Claims (3)

[Claims] 1. A scanning device is arranged at a fixed position corresponding to a platen, and means for scanning an image of an original moving at a constant speed is constituted, and a platen roller is arranged at a position corresponding to the platen. Conveying roller devices are arranged upstream and downstream of the rollers to form a scanning unit conveying device, and a means for conveying the original document at a constant speed is configured by the scanning unit conveying device, and the original document placed on the original tray is fed. The originals are sent one by one toward the original conveying path through the apparatus, and the originals are aligned between the conveying roller device arranged in the original conveying path and the roller device upstream of the platen roller. In a document conveying device for reading an image while conveying a sheet, the document conveying path is configured as a curved path, and means for performing an aligning action on a document in a state of being curved in the document conveying path is provided. An outer guide member that defines the document transport path is disposed, an inner guide member corresponding to the outer guide member is swingably provided, and the document aligned in the document transport path is transported by a scanning unit transport device. The document feeder of the image reading apparatus, characterized in that the inner guide member is swung while following the operation of reducing the loop of the document. 2. The inner guide member arranged in the original conveying path is a combination of two swing guide plates,
The guide plates are rocked by providing drive means for supporting the other ends of the two guide plates via a support shaft in a state where the front end portions of the two guide plates are brought into contact with each other and swinging the two guide plates in conjunction with each other. 2. The document feeding device of the image reading apparatus according to claim 1, wherein the driving means for performing the driving is synchronized with the driving of the roller device of the scanning unit feeding device. 3. The inner guide member arranged in the document conveying path is composed of two guide plates, and the two guide plates are swingably provided so that the leading end portions of the two guide plates are in contact with each other, and the two guide plates are provided. The document feeding device of the image reading apparatus according to claim 1, further comprising: a swinging unit that swings the guide plate according to the pressure of the document.