JP3951718B2 - Paper feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for reading an image while conveying a sheet document, and more particularly to a sheet feeder provided with means for correcting and feeding a skewed sheet document conveyed in a document conveyance path by a guide member.
[0002]
[Prior art]
In an image forming apparatus such as an electrophotographic copying machine or a facsimile machine, an image reading device is disposed on an upper part of an image recording unit using an electrophotographic method on the upper part of the apparatus body, and image information read by the image reading apparatus. Based on the above, the recording unit performs printing on the recording paper. In general, the image reading apparatus is provided with a combination of an FBS (flatbed scanner) and an ADF (automatic document feeder). In the FBS, a page of a book set on a large size platen is used as it is. It is configured so that it can be read and a sheet document can be read. In the ADF, the scanning device used in the FBS function is stopped at a fixed position, and is configured to read the sheet document while being conveyed. The document tray and the discharge tray are arranged vertically, A scanning device that connects between both trays by a substantially U-shaped document conveying path that faces sideways, conveys a large number of documents set on the document tray one by one at the document separation unit, and conveys them to the reading unit. Reading is performed by.
[0003]
[Problems to be solved by the invention]
However, there are cases where a skewed state occurs in the document to be transported in the curved document transport path, or the document is fed while being set obliquely on the document tray. Then, when the sheet original is conveyed toward the scanning unit while being skewed, the read image information of the original read while being skewed is, as a matter of course, an image formed obliquely. A recorded image formed based on the read image information is also skewed. Further, when the document is transported along the document transport path while the document is skewed, the corners of the oblique document may enter between the guide plates of the document transport path or the gaps of the guide member that guides the document corresponding to the ADF. As a result, there is a problem that the conveyance is not performed well. The reason why the sheet document is skewed is that the feeding by the pickup roller and the separation roller of the document separating device does not act on the center in the width direction of the sheet document to be fed, or the retard in the document separating device. It is assumed that the nip action between the roller and the separation roller is not uniformly applied in the width direction of the document. In addition, there is a great influence when the length of the guide plate on which the document slides in the curved document transport path varies depending on the moving direction of the document.
[0004]
The present invention addresses the problem of document skew as described above by causing the auxiliary guide member arranged in the document transport path to appear and retract, thereby making the document movement distance on both sides in the document width direction correspond to skew. It is an object of the present invention to provide a correction device.
[0005]
[Means for Solving the Problems]
The present invention relates to a sheet feeding device that feeds a sheet document to a reading position and reads the document. According to a first aspect of the present invention, an adjusting means for adjusting a length of a surface for guiding an original is provided at a curved portion of the original conveying path upstream from the reading position, and the adjusting means is configured to adjust the length of the original conveying path. A plurality of rib members that are arranged so as to be able to appear and retract on a guide plate surface on which a document on a curved portion slides, and a back surface of the plurality of rib members, and are provided so as to be swingable around a central portion of the document conveyance path. And a pressing means .
[0008]
As described above, it is possible to easily eliminate the skew of the original by adjusting the length of the guide surface of the original as appropriate by the adjusting means provided in the curved portion of the original conveyance path, and the read original image Good quality can be maintained. Further, in order to eliminate the skew feeding, it is possible to easily cope with the problem by providing an additional rib member to the guide plate of the document conveyance path and adjusting the protruding amount of the rib member. Then, the length of the guide surface on which the document slides can be changed by the rib member in the document transport path, so that the document can be transported toward the reading unit without causing skew.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the apparatus of the present invention will be described according to the illustrated example. An ADF 1 shown in FIG. 1 is connected between a document tray 2 and a discharge tray 3 via a horizontally-oriented substantially U-shaped document conveyance path, and a sheet document conveyed in the document conveyance path has an ADF function. The image is read at the portion of the small platen 28 provided corresponding to the above and discharged toward the discharge tray 3. A paper feeding device 5 that feeds a document from the document tray 2 and conveys the document in a document conveyance path includes a pickup roller 6 that can be moved up and down by an arm 6a, a document separation device 7, and a conveyance roller device 10 in the moving direction of the document. In the reading unit corresponding to the small platen 28, the large-diameter roller 20 and the two press rollers 21 and 22 are arranged.
[0010]
In the document conveying apparatus configured as described above, the sheet feeding device 5 takes out a sheet document from the document tray 2 by the pickup roller 6 and applies a separating action by the document separating device 7 to separate the separated documents one by one. Transport toward the downstream part. The document separation device 7 is provided with a feed roller 8 driven in the direction of conveying the document and a retard roller 9 driven in the return direction so as to face each other, and the document separation device 7 is in a state where two or more documents overlap each other. When entering, only the upper one is sent to the downstream part. A conveyance roller device 10 is disposed downstream of the document separation device 7 and is fed toward the conveyance unit by a large-diameter roller 20 disposed as a scanning unit roller device. A cover 4 that covers the entire apparatus frame is provided above the ADF 1, and the opening of the document conveyance path by opening the upper frame is configured in the same manner as in the case of a conventional apparatus. The laterally substantially U-shaped document conveyance path 11 includes an outer guide plate 12 that guides both sides of the document and an inner guide plate 12a arranged at a predetermined interval, and the conveyance roller device 10 and the large-diameter roller 20 are separated from each other. As a means for correcting the skew of the document by the adjusting unit 13 when the document passes through the curved part of the document conveying path 11 by providing a curved part between them and the adjusting unit 13 for the curved part. Make it work.
[0011]
The large-diameter roller 20 provided at a position facing the small platen 28 and used as a scanning unit roller device is configured to read a document by a scanning device positioned below the small platen 28 while conveying the document at a constant speed. Yes. In the scanning unit, the large-diameter roller 20 driven at a constant speed reads the original while conveying the original at a constant speed. In the scanning unit, press rollers 21 and 22 are arranged on both side portions in the upstream and downstream direction of the small platen 28, and the scanning unit is operated in a state where the original is pressed against the large-diameter roller 20 by the two press rollers 21 and 22. Pass through the image so that no movement noise is generated in the image reading information. Then, the document that has passed through the scanning section passes through a discharge path 24 and is discharged by a discharge roller device 25 to a discharge tray 3 provided on the platen cover.
[0012]
The ADF 1 configured as described above can be combined with an image reading apparatus as shown in FIG. The image reading apparatus 30 shown in FIG. 2 is configured by combining an FBS function for reading a document of a book and an ADF function. The image reading apparatus 30 corresponds to a platen glass 27 corresponding to the FBS function and the ADF function. The small platen 28 is arranged on the upper part of the main body frame of the image reading device 30. As the image reading device function, a scanning device 31 that can move inside the frame is provided. The scanning device 31 is provided with two carriages 32 and 34 in order to read the image by moving along the lower surface of the platen glass 27 as in the case of the conventional general image reading device. The carriage is driven at a constant speed using drive transmission means such as wires 38 and 38a using drive pulleys 37 and 37a arranged at one end of the apparatus.
[0013]
In the scanning device 31, a full-rate carriage 32 that moves at a constant speed along the entire surface of the platen glass 27 is provided with a lamp 33 and one mirror m 1, and moves in the same direction at half the speed of the carriage 32. The half-rate carriage 34 is provided with two mirrors m2 and m3. Then, the lamp 33 irradiates the image surface of the document, the reflected light is reflected by the three mirrors m1 to m3, condensed by the lens 35 onto the CCD 36, and the image information obtained by converting the optical signal into an electrical signal is obtained. The signal is transmitted to the image signal processing means of the image reading apparatus. The image signal transmitted to the image reading apparatus is used as an image writing signal for the photoconductor in the recording unit of the copying machine. In the case of an image forming apparatus provided with a facsimile function, the image signal is transmitted through a telephone line. It is also possible to transmit to the facsimile machine.
[0014]
When reading an image of a document by the ADF 1, the two carriages 32 and 34 of the scanning device 31 are moved and positioned to the left in the figure, and the image of the document passing through the document transport path 11 of the ADF 1 is The image information is read from the small platen 28 and output from the CCD 36 in the same manner as in the FBS. When the ADF function is used, it is possible to operate the scanning device corresponding to the ADF by setting a document on the document tray 2 and pressing an operation start button of the image reading apparatus. This can be done in the same way as Further, in this embodiment, the upper surface of the platen cover 29 provided on the upper portion of the image reading device 30 is configured as a discharge tray so that the document read using the ADF function can be easily handled.
[0015]
In the sheet feeding device 5 of the ADF 1 configured as described above, a document that is picked up by the pickup roller 6 from the document tray 2 and subjected to the separating action by the document separating device 7 is conveyed when being conveyed by each of the roller devices. Alternatively, skewing may occur when being conveyed while sliding on the guide plate of the document conveying path. Therefore, in order to eliminate the skew when the document is skewed and to convey the skew toward the scanning unit, the adjustment unit 13 is made to correspond to the curved portion of the document transport path 11. It is arranged. A plurality of rib members 15... Provided in the adjustment unit 13 are arranged in a direction orthogonal to the document conveyance direction (main scanning direction) via a slit provided in the upper guide plate 12, and the document conveyance path 11 extends from the slit. It is provided so as to appear in the inside. Then, by adjusting the amount by which each of the rib members 15... Protrudes from the upper guide plate toward the document conveying path, the document passing through the document conveying path 11 is allowed to move to the upper guide with the rib member added. The length of sliding on the plate 12 is set so as to be different on both sides in the width direction of the document so that the skew of the document can be eliminated during conveyance in the document conveyance path 11.
[0016]
In the example shown in FIGS. 3 and 4, the rib members 15... Are individually supported at predetermined intervals with respect to the upper guide plate 12, and the rib members 15. Are omitted) from the original transport path 11. The rib member 15 is provided with a flange member 16a provided with a screw hole in the vertical direction at the upstream end in the document conveying direction, and the shaft member 16 is provided at a predetermined position. In order to support the rib member 15 provided with the shaft member 16 and the flange member 16a, the upper guide plate 12 is provided with a shaft support portion 14 and a screw adjusting portion 14a, and the shaft member 16 of the rib member 15 is connected to the shaft support portion 14. The flange member 16a at the end is positioned on the screw adjusting portion 14a, and the screw 14b projects the inner guide surface of the rib member 15 into the document conveyance path (projects from the inner surface of the upper guide plate of the rib member). Adjust the height.
[0017]
When a plurality of the rib members 15... Are arranged at a predetermined interval with respect to the width direction of the document conveying path 11, the rib members 15. By adjusting the protrusion amount, it is possible to correct the skew of the document. For example, when it is visually detected that the document is skewed, the sliding distance (guide distance by the rib member) with respect to the guide member of the document with respect to the adjustment unit 13 with respect to the delay side of the document. And a process of increasing the sliding distance on the leading side of the document. In order to adjust the distance for guiding the original, the screw 14b is moved up and down to swing the rib member 15 via the shaft support portion 14, and the arc-shaped guide surface of the inner surface of the rib member 15 is moved to the upper guide plate 12. Try to invade the inner surface.
[0018]
That is, when adjusting the sliding distance of the document with respect to the guide, the outer guide surface on which the document is slid is moved by moving the rib member 15 protruding to the document conveyance path 11 outward and approaching the upper guide plate 12. become longer. On the other hand, when the rib member 15 is protruded greatly toward the document conveyance path, the guide surface on which the document slides is set short. Therefore, with respect to the plurality of rib members 15 arranged in the width direction of the document conveying path, screws are tightened on one side of the document conveying path to shorten the protruding amount of the rib member 15, and screws 14b are arranged on the other side. By adjusting the length of the rib member 15 to be increased by loosening, it is possible to easily adjust the skew of the document generated in the upstream portion of the document transport path or the curved portion 11a.
[0019]
The examples shown in FIGS. 5 and 6 show a case in which the rib members 15... Provided in the adjustment portion of the document conveyance path are configured to be adjusted using one rib pressing member 18. In the case where the plurality of rib members 15 are configured as one unit, the plurality of rib members 15 are supported in a skewered manner via one support shaft 17 so that the support shaft 17 is supported by the upper guide plate 12. Or it is pivotally supported by the device frame. Further, a rib pressing member 18 is disposed behind the plurality of rib members 15... And the central portion in the length direction of the rib pressing member 18 (the central portion in the width direction of the document conveying path) is a fulcrum 18a. It is provided so as to be supported by a frame so that it can be swung around the fulcrum 18a.
[0020]
In order to adjust the protruding amount of the rib member 15, as shown in FIG. 6, the rib pressing member 18 is moved to the support shaft 17 side or moved away from the support shaft 17. The amount of each rib member 15 protruding into the document conveyance path changes around the support shaft 17. Then, after the rib pressing member 18 is swung to adjust the protruding amount of each rib member 15..., Screws (not shown) are inserted into the long holes 19 a of the end fixing portions 19 provided at both ends thereof. By mounting and fixing, the sliding distance of the document in the adjusting unit 13 is set to a different value on both sides of the document transport path.
[0021]
In the example of the rib member 15 shown in FIG. 5, the state of the guide surface of the document conveyance path when the rib holding member 18 is moved will be described with reference to FIGS. In the example of the rib member 15 shown in FIGS. 5 and 6, it is assumed that the document slides while pushing up the guide surface against the weight of the rib member 15, The rib member 15 needs to be configured as a very light one. On the other hand, when a spring 17a is provided that swings the rib member 15 upward, that is, in a clockwise direction with respect to the support shaft 17, a force that causes an excessive skew is applied to the conveyed document. Therefore, the guiding operation can be satisfactorily performed by the rib members 15.
[0022]
As shown in FIG. 7A, when the rib member 15 is slightly protruded from the inner surface of the upper guide plate 12, the length of the guide surface of the document is increased. In FIG. Since the rib member 15 protrudes greatly, the guide surface on which the document slides is set short. Further, in the example of FIG. 5B, since the sliding length is set to a medium level, the original is moved according to the skew state of the original that is conveyed in the original conveying path and read by the scanning unit. The length of the guide surface of the document is adjusted on the left and right in the width direction of the transport path 11 so as to eliminate the skew that has occurred in the document. When the rib pressing member 18 is used to adjust the plurality of rib members 15... At once, the skew adjustment can be performed by swinging the rib pressing member 18 about the fulcrum 18a. However, when rib members such as those shown in FIGS. 3 and 4 are used, it is necessary to perform screw tightening adjustment on each rib member. When the adjusting means as shown in FIG. 4 is used, for example, when the number of rib members is small, it can be handled with a relatively simple configuration.
[0023]
In the example in which the rib members 15... Are arranged on the curved portion 11 a of the document conveying path 11, the rib member 15 can be made of a plate-like material such as plastic or metal. What is necessary is just to form the curvature of this guide surface etc. corresponding to the curvature of the curved part 11a. Further, instead of using the plurality of rib members, as shown in a rear view of FIG. 8A and a side view of FIG. It is also possible to form the adjusting portion 13a using an auxiliary guide plate 40 configured as a single curved plate. The auxiliary guide plate 40 is provided with a support portion 41 at the center in the width direction and held at a predetermined position of the apparatus frame, and is provided so as to be swingable in the direction of the arrow with the support portion 41 as the center.
[0024]
In the example shown in FIG. 8, one end of the auxiliary guide plate 40 is moved to the lower guide plate 12a by swinging the auxiliary guide plate 40 around a support portion 41 provided upstream in the document conveying direction. Swing so that the other end is separated from the lower guide plate. Then, the document passing through the curved path 11a is adjusted so as to eliminate skew by changing the distance (length) of sliding on the guide surface on the left and right in the moving direction. Further, when the support portion is configured to be supported by an axis parallel to the document conveying direction, the swinging action of the auxiliary guide plate 40 can be easily adjusted. Further, even when the auxiliary guide plate 40 is configured as the one curved plate member, after the swing position is adjusted, the support portion of the auxiliary guide plate 40 or a part of the main body is fixed by the fixing means. If held, it is possible to maintain a state in which the skew of the conveyed document is eliminated. If adjustment of the skew of the document is performed by the adjustment unit at the time of shipment of the image forming apparatus, the adjusted product can be delivered to the user, and the document can be skewed while using the ADF. Even when a line is generated, it is possible to easily eliminate the skew by adjusting the skew in the adjustment unit.
[0025]
【The invention's effect】
Since the apparatus of the present invention is configured as described above, the skew of the document is adjusted by appropriately adjusting the length of the guide surface of the document by the adjusting means provided in the curved portion of the document transport path. Can be easily eliminated, and the image quality of the read original can be maintained satisfactorily. Further, in order to eliminate the skew feeding, it is possible to easily cope with the problem by providing an additional rib member to the guide plate of the document conveyance path and adjusting the protruding amount of the rib member. Then, the length of the guide surface on which the document slides can be changed by the rib member in the document transport path, so that the document can be transported toward the reading unit without causing skew.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of an ADF.
FIG. 2 is an explanatory diagram of a configuration of an image reading apparatus.
FIG. 3 is an explanatory diagram of a rib member.
FIG. 4 is an explanatory diagram of a state in which a rib member is attached to an upper guide plate.
FIG. 5 is an explanatory diagram of an example in which a plurality of rib members are collectively provided.
FIG. 6 is an example of one rib member shown in FIG.
FIGS. 7A to 7C are explanatory views showing a state of a protruding amount of the rib member. FIGS.
FIG. 8 is an explanatory diagram of an example using an auxiliary guide plate, in which (a) is a rear view and (b) is a side view.
[Explanation of symbols]
1 ADF, 2 document tray, 3 discharge tray,
5 Paper feeder, 6 Pickup roller, 7 Document separator,
8 feed rollers, 9 retard rollers,
10 transport roller device, 11 document transport path, 12 upper guide plate,
12a Lower guide plate, 13 adjustment section, 14 shaft support section,
15 rib member, 16/17 support shaft, 18 rib holding member,
19 end fixing part, 27 platen glass, 28 small platen,
29 platen cover, 30 image reading device, 31 scanning device,
32 full rate carriage, 33 lamp,
34 half-rate carriage, 35 lens,
36 CCD, 37 pulley, 38 wire,
40 Auxiliary guide plate, 41 Shaft support.

Claims (1)

In a sheet feeding device that feeds a sheet document to a reading position and reads the document,
An adjusting means for adjusting the length of the surface for guiding the document is provided at the curved portion of the document conveyance path upstream from the reading position ;
As the adjusting means, a plurality of rib members disposed so as to be able to project and retract on a guide plate surface on which a document on a curved portion of the document conveyance path slides, and a central portion of the document conveyance path located on the back surface of the plurality of rib members And a pressing means provided so as to be swingable with respect to the fulcrum .

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