JP3527395B2 - Automatic document feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder used in a document reading section of a copying machine, a scanner device, a facsimile device or the like.

[0002]

2. Description of the Related Art FIG. 9 is a schematic block diagram of a conventional automatic document feeder, and FIG. 10 is a block diagram showing an enlarged main part of the apparatus shown in FIG. The rollers 2 are pressure plates, and the pickup roller 1
Collaborates with the pressure plate 2 that presses the originals stacked at the predetermined original setting position against the pickup roller 1,
Feed the paper while separating it. Reference numeral 3 is a feed roller, and 4 is a friction reverse roller, which constitutes a document separating / feeding device for feeding the multi-fed documents one by one by a known frictional action by both rollers 3, 4.

Further, 5 is a scanner section for optically reading the image information of the fed original on the scan line L, 6 is a white pressing plate for pressing the original on the scanner section 5,
Reference numeral 7 is a registration roller, and 8 is a registration pressure roller, and both rollers 7 and 8 feed the document to the scan line L at a constant timing. 9 is a discharge roller,
Reference numeral 10 denotes a sheet discharge pressure roller around which a plurality of small projections 10a for ejecting the original document are projected. Both rollers 9 and 10 hold the original document moved from the scanner unit 5 and the original document end. The part is kicked out and discharged.

In the structure of the conventional automatic document feeder,
A registration roller pair composed of a registration roller 7 and a registration pressure roller 8 on the upstream side of the document transport path R with respect to the scanner section 5, and a registration roller composed of a paper discharge roller 9 and a paper discharge pressure roller 10 on the downstream side of the document transport path R. Paper feed and paper discharge to the scanner unit 5 are performed by the roller pair and the paper discharge roller pair.

[0005]

In the conventional automatic document feeder, the pair of registration rollers on the downstream side of the document conveyance path R with respect to the scanner section 5 is also used as the pair of paper discharge rollers. Although the cost can be reduced by adopting such a configuration, at the time of reading a document, as shown in FIG. 11, the leading end portion of the document D is located on the side of the white pressing plate 6 and the discharge roller 9 and is the document transport path R. In the above, since there is no member for restricting the upward movement, when the small protrusion 10a for kicking out the original of the discharge pressure roller 10 repels it upward, the original D sways in a wavy manner in the scanner unit 5, The reading target surface of the document D floats on the scan line L, causing an optical defocus of the scanner unit 5 with respect to the reading target, which may cause a problem that the read image is distorted. It was

Therefore, in order to prevent the tip portion of the original document D from being repelled between the white pressing plate 6 and the paper discharge roller 9, the original document for the scanner section is utilized by utilizing the configuration shown in Japanese Utility Model Laid-Open No. 4-58543. It is also conceivable to provide a plurality of sheet-like elastic bodies on the roller on the downstream side of the transport path so as to rotate together with the roller so as to hold the document.
There is a problem that the configuration becomes complicated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and to prevent the document surface from swaying on the scan line which tends to occur when the document enters the discharge roller portion. To provide a device.

[0008]

In order to achieve the above-mentioned object, an automatic document feeder of the present invention is a document placed on a document reading section and an upper portion of the document reading section by a registration roller and a resist pressure roller. An automatic document feeder configured to discharge a document that has been fed between a pressure plate and a document reading unit by a discharge roller and a discharge pressure roller having a document kicking unit. The end portion on the side of the paper discharge roller in is disposed adjacent to the side surface of the paper discharge roller, and with this configuration, by extending the end portion of the document pressing plate close to the side surface of the paper discharge roller,
Since the original can be pressed, the shaking of the original can be suppressed.

Further, according to the present invention, in the original pressing plate, only the end portion facing the paper discharge roller is extended,
By installing adjacent to the side surface of the discharge roller,
By restricting the sway of the document pressing plate to only the discharge roller part, it is possible to suppress the sway of a document made of thin paper, that is, a so-called weak document by the narrow passage consisting of the document pressing plate and the lower guide part. It is possible to prevent the occurrence of a conveyance failure such as jamming due to the paper feed regulation.

Further, according to the present invention, a document is fed by a registration roller and a registration pressure roller between a document reading unit and a document pressing plate installed above the document reading unit, and the document passed through the document reading unit. In an automatic document feeder having a structure in which a sheet is discharged by a sheet discharge roller and a sheet discharge pressure roller having a document kicking portion, an end portion of the sheet discharge roller is on the upper surface of the document pressing plate on the sheet discharge roller side. With a guide plate that extends to a position close to the side surface of the document, this configuration provides a guide plate on the upper surface of the document pressing plate to widen the gap between the guide plate and the lower guide section to prevent document shaking. By reducing the paper feed regulation for prevention, it is possible to suppress the shaking of the document due to the guide plate that is close to the side surface of the paper discharge roller, and to prevent the conveyance failure.

Further, according to the present invention, the guide plate is provided only in a portion of the document pressing plate that faces the paper discharge roller, so that the guide plate is provided with only the paper discharge roller portion as the shake suppressing portion. It is possible to prevent the occurrence of a conveyance failure such as a jam by further weakening the sheet feed regulation for suppressing the shaking due to the narrow passage including the plate and the lower guide portion.

Further, according to the present invention, a document is fed by a registration roller and a registration pressure roller between a document reading unit and a document pressing plate installed above the document reading unit, and the document passed through the document reading unit. In an automatic document feeder having a structure in which the sheet is discharged by a sheet discharge roller and a sheet discharge pressure roller having a document kicking portion, an end portion of the sheet is discharged at a part of the document pressing plate on the sheet discharge roller side. An extension portion extending to a position adjacent to the side surface of the roller is provided, and the diameter of the discharge roller portion facing the extension portion is formed to be smaller than other portions. In the same manner as described above, it is possible to suppress the shaking of the document by the document pressing plate, and it is possible to prevent the trouble such as the winding of the extension portion by the paper discharge roller due to the extension portion coming too close.

Further, according to the present invention, the end portion of the extending portion of the document pressing plate is extended to the side surface of the small diameter portion without contacting the large diameter portion adjacent to the small diameter portion of the paper discharge roller. By letting it out, the original pressing plate and the side surface of the paper ejection roller can be brought close to each other so as to overlap with each other, so that troubles such as involvement of the extending portion can be prevented and the original can be shaken more effectively. Can be suppressed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The configuration of the present embodiment is applied to the automatic document feeder as shown in FIG. 9, and the members corresponding to the members described with reference to FIGS. , Its detailed description is omitted.

FIG. 1 is a block diagram of a main part of an automatic document feeder for explaining a first embodiment of the present invention, FIG. 2 is a plan view of the main part of FIG. 1, and 5 is a plan view of FIG. Like the device,
The scanner unit, which is a document reading unit that optically reads the image information of the document fed from the pair of registration rollers on the scan line L, 9 is a sheet discharge roller, and 10 is a small protrusion 10a for kicking the document around. A plurality of ejecting pressure rollers provided in a projecting manner. The rollers 9 and 10 clamp the document moved from the scanner section 5 and eject the document by pushing the edge of the document outward.

Reference numeral 11 is a white pressing plate which is a document pressing plate for pressing the document against the scanner section 5. One end portion (the left end side in the drawing) of the white pressing plate 11 is a discharge roller 9 and a discharge pressure. Laura 10
Adjacent to the side surfaces of the rollers 9 and 10 to the extent that they do not interfere with the operation of the rollers. Therefore, as shown in FIG. 2, the white pressing plate 11 (shown by a chain double-dashed line in FIG. 2) is closer to both rollers 9 and 10 than the conventional white pressing plate 6 (shown by a solid line in FIG. 2). Has been extended to.

Therefore, as shown in FIG. 1, in the document D moving in the scanner section 5, the narrow document conveyance path R formed by the white pressing plate 11 and the lower guide section 12 reaches near both rollers 9, 10. Therefore, the leading edge of the document D is located at both rollers 9 and 10, and particularly the small protrusion 10 for kicking out the document of the discharge pressure roller 10.
Original D, even if it comes in contact with a and is repelled upward
Swaying as a whole is suppressed.

Therefore, since the inadvertent movement of the document D on the scanner unit 5 such as upward swing and floating is always regulated, the document is mounted on the scanner unit 5 at the scan line L of the scanner unit 5. The optical reading means can be maintained in a state of being properly focused, and the accuracy of the read information is improved.

FIG. 4 is a block diagram of the essential parts of an automatic document feeder for explaining the second embodiment of the present invention. The white pressing plate 6 has a paper discharging roller 9 and a paper discharging roller on its upper surface. One end 15a of the guide plate 15 is fixed to the pressure roller 10 side. The other end 15b of the guide plate 15 is adjacent to the side surfaces of the rollers 9 and 10 to the extent that they do not interfere with the operation of the rollers 9 and 10.

Therefore, in the apparatus according to the first embodiment, a strong feed restriction is applied to the original document by the narrow original document conveyance path R, and an original document made of thin paper, that is, a so-called weak original document is jammed. However, since the guide plate 15 is provided on the upper surface of the white pressing plate 6 in the device according to the second embodiment, the first plate is provided between the guide plate 15 and the lower guide portion 12 at this portion. Compared with the apparatus according to the embodiment, the original conveyance path R having a vertical width S slightly longer than other portions can be provided. Therefore, it is possible to prevent the conveyance failure such as the document jamming due to the paper feed restriction due to the shake suppression. Moreover, by extending the guide plate 15 as described above, it is possible to prevent the entire document from swaying even if the document front end is repelled as in the apparatus according to the first embodiment.

FIG. 3 is a plan view showing a modified example of the apparatus according to the first embodiment. In this example, the discharge roller 9 and the discharge pressure roller are provided at one end of the white pressing plate 11.
Only the portion 11a facing the roller 10 is extended so as to be adjacent to the side surfaces of the rollers 9, 10.

With such a configuration, the shaking suppression portion by the white pressing plate 11 is installed only on the rollers 9 and 10 where the repulsion of the document is likely to occur. The following document, that is, a so-called weak document is jammed due to jamming due to paper feed regulation for suppressing shaking due to a narrow passage including the white pressing plate 11 and the lower guide portion 12 shown in FIG. Can be prevented.

FIG. 5 is a plan view showing a modified example of the apparatus according to the second embodiment. In this example, the discharge roller 9 and the discharge pressure roller 10 are provided on the upper surface of the white pressing plate 6.
The guide plate 15 is provided so that only the portion facing the roller 9 and 10 is close to the side surfaces of the rollers 9 and 10 and the shaking suppression portion 15b of the guide plate 15 is provided only near the small protrusion 10a on the roller 9 and 10 side.

With this structure, the shaking suppressing portion 15b of the guide plate 15 is limited to the vicinity of the small protrusion 10a on the rollers 9 and 10, and the guide plate 15 and the lower guide portion 12 are provided as shown in FIG. A slightly longer original conveying path R having a width S is formed between the guide plate 15 and the lower guide portion.
Since the paper feed regulation for suppressing the shaking due to the narrow passage composed of 12 is further weakened, it is possible to prevent the occurrence of conveyance failure such as jamming of a document having a weak waist, and the document transporting property is improved.

By the way, as shown in FIGS. 4 and 5, the positions of the guide plate 15 which is a part of the white pressing plate 6 are adjacent to the side surfaces of the rollers 9 and 10 at both ends on the rollers 9 and 10 side. It is possible to prevent the document from shaking by providing the shake suppressing portion 15b which is an extending portion extending up to, but especially since the tip of the shake suppressing portion 15b is adjacent to the side surface of the paper discharge roller 9. However, if the adjacent distance between the two is too short, there is a possibility that the shake suppressing portion 15b is sometimes caught by the paper discharge roller 9 during the conveyance of the document.

Therefore, in the third embodiment of the present invention, FIG.
As shown in the configuration diagram of FIG. 7 and the plan view of FIG. 7, the diameter of the discharge roller 9 adjacent to the tip of the shake suppressing portion 15b of the white pressing plate 6 is made smaller than the other portion (small diameter portion 9a), and the shake Suppression point
It prevents the inclusion of 15b.

The small diameter portion 9a and the large diameter portion 9b of the paper discharge roller 9
In the case of the two-stage configuration of the above, it is effective to prevent the document from shaking by forming the small diameter portions 9a on both sides close to the portion where the small protrusion 10a for ejecting the document is installed in the discharge pressure roller 10. It is desirable to do. On the other hand, if the length of the small diameter portion 9a in the roller axial direction is made longer than that of the large diameter portion 9b, the document conveying force will be reduced, which is not desirable. Further, since the small diameter portion 9a is provided to prevent the sway suppressing portion 15b from being caught, the width of the small diameter portion 9a in the roller axis direction is the sway suppressing portion.
It is desirable to make it slightly wider than the width of 15b.

FIG. 8 is a block diagram showing a modification of the device according to the third embodiment. In this example, the end portion of the shake suppressing portion 15b of the guide plate 15, which is a part of the white pressing plate 6, is removed. The large diameter portion 9b of the paper roller 9 is extended to the side surface of the small diameter portion 9a without contacting the large diameter portion 9b adjacent to the small diameter portion 9a. The guide plate 15 is installed so that the shake suppressing portion 15b of the guide plate 15 is close to or overlaps with the inside.

With this configuration, the effect of preventing the swaying suppression portion 15b from being caught can be obtained, and
Compared with the configuration shown in FIGS. 6 and 7, the edge of the guide plate 15 and the side surface of the paper discharge roller 9 come closer to each other so as to overlap each other, so that the shaking of the document is more effectively prevented. Done.

[0030]

As described above, according to the automatic document feeder of the present invention, even if the sheet discharge pressure roller having the document kicking portion is installed, the document pressing plate or the guide plate always keeps Since inadvertent movements such as shaking and floating of the document on the scanner unit are restricted, the document can be maintained in a state where it can be properly read on the scan line of the scanner unit, and the accuracy of the read information is improved. become.

Also, when an original made of thin paper, that is, a so-called weak original, is subjected to paper feed regulation for suppressing shaking by a narrow passage formed by the original pressing plate or the guide plate and the lower guide portion, etc., it is jammed. It is possible to prevent the occurrence of a conveyance failure such as the occurrence of a conveyance error.

Further, even if the leading end of the document pressing plate or the guide plate is arranged adjacent to the side surface of the roller, it is possible to prevent the possibility that they are caught by the roller during document transportation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part in an automatic document feeder for explaining a first embodiment of the present invention.

FIG. 2 is a plan view of a main part of FIG.

FIG. 3 is a plan view showing a modified example of the device according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a main part in an automatic document feeder for explaining a second embodiment of the present invention.

FIG. 5 is a plan view showing a modified example of the device according to the second exemplary embodiment of the present invention.

FIG. 6 is a configuration diagram of a main part in an automatic document feeder for explaining a third embodiment of the present invention.

FIG. 7 is a plan view of a main part of FIG.

FIG. 8 is a configuration diagram of a main part showing a modified example of the device according to the third embodiment of the present invention.

FIG. 9 is a schematic configuration diagram of a conventional automatic document feeder.

10 is a configuration diagram showing an enlarged main part of the apparatus of FIG.

11 is an explanatory diagram of a problem in the conventional device of FIG.

[Explanation of symbols]

1 ... Pickup roller, 2 ... Pressure plate, 3 ... Feed roller, 4 ... Friction reverse roller, 5 ...
Scanner section, 6, 11 ... White pressing plate, 7 ... Registration roller, 8 ... Registration pressure roller, 9 ... Paper ejection roller,
9a ... small diameter part of discharge roller, 9b ... large diameter part of discharge roller, 10 ... discharge pressure roller, 10a ... small projection of discharge pressure roller, 12 ... lower guide part, 15 ... guide plate, 15b …
A place where the guide plate is suppressed from shaking.

Claims (6)

(57) [Claims] 1. A document is fed between a document reading unit and a document pressing plate installed above the document reading unit by a resist roller and a resist pressure roller, and a document passing through the document reading unit is ejected by a discharge roller. In the automatic document feeder having a configuration in which the sheet is ejected by the sheet ejection roller and the sheet ejection pressure roller with the document ejection section,
An automatic document feeder, wherein an end of the document pressing plate on the side of the paper discharge roller is disposed adjacent to a side surface of the paper discharge roller. 2. The automatic original document according to claim 1, wherein only the end portion of the original document pressing plate facing the paper ejection roller is extended so as to be adjacent to the side surface of the paper ejection roller. Feeding device. 3. A document is fed between a document reading section and a document pressing plate installed above the document reading section by a registration roller and a resist pressure roller, and a document passing through the document reading section is ejected by a roller. In the automatic document feeder having a configuration in which the sheet is ejected by the sheet ejection roller and the sheet ejection pressure roller with the document ejection section,
An automatic document feeder, wherein a guide plate is provided on the upper surface of the document pressing plate on the paper discharge roller side, the guide plate having an end extending to a position adjacent to the side surface of the paper discharge roller. 4. The automatic document feeder according to claim 3, wherein the guide plate is provided only in a portion of the document pressing plate that faces the paper discharge roller. 5. A document is fed between a document reading unit and a document pressing plate installed above the document reading unit by a resist roller and a resist pressure roller, and a document that has passed through the document reading unit is discharged by a roller. In the automatic document feeder having a configuration in which the sheet is ejected by the sheet ejection roller and the sheet ejection pressure roller with the document ejection section,
An extension part is provided at a part of the document pressing plate on the side of the paper ejection roller, the end part extending to a position adjacent to the side surface of the paper ejection roller, and the paper ejection roller facing the extension part. An automatic document feeder, wherein the diameter of a part is smaller than that of other parts. 6. The end portion of the extending portion of the document pressing plate is extended to the side surface of the small diameter portion without contacting the large diameter portion adjacent to the small diameter portion of the paper discharge roller. The automatic document feeder according to claim 5.