JPH058906A - Document automatic conveyer - Google Patents

Abstract

PURPOSE:To perform stable conveyance with a small diagonal feed by suppressing unevenness of a diagonal feed amount generated by a difference between conveying modes (conveying path) of one side-document, both-side document, etc. CONSTITUTION:A loop forming diagonal feed correcting means is provided in an optimum part in accordance with each conveying mode (both-side document read mode, one-side document read mode), and further so that a nip line of these diagonal feed correcting means (roller 12 and roller 11, roller 12 and roller 26) can be independently adjusted.

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, and more particularly, to a structure of a double-sided document automatic feeder which is combined with, for example, an image forming apparatus.

[0002]

2. Description of the Related Art Some conventional double-sided document feeders are constructed as shown in FIG. In this device,
The originals separated one by one in the separating unit 101 are abutted against the nip of the registration roller pair 102 to form a loop for skew correction, and then fed onto the platen glass 103 and stopped. When forming a single-sided original, an image is formed in this state.

In the case of a double-sided original, the reversing roller 104 is conveyed from this state in the direction opposite to the paper feeding direction.
After rotating around the circumference, the nips of the registration roller pair 102 are again brought into contact with each other to form a loop, which is fed onto the platen glass 103 to form an image on the back side of the double-sided original. Next, in the same manner as above, the reversing roller 104 is again used.
Similarly, after the skew correction is performed around the circumference, the surface image is formed on the platen.

As described above, in the conventional double-sided document feeder, the leading end is abutted by the same nip of the pair of registration rollers 102 when feeding a single-sided document and when feeding a double-sided document three times. Was formed to perform skew correction.

[0005]

However, in the above-mentioned conventional example, the leading end of the original is the nip of the registration roller during the first loop formation of the single-sided original and the double-sided original and during the second and third loop formation of the double-sided original. Is the same, but the parts other than the leading end are in completely different paper paths. So, for example,
Regarding the degree of bending of the central portion of the document, when it is one-sided as shown in FIG. 9, it is in a substantially linear path after the loop portion at the tip, whereas when it is both-sided as shown in FIG. It is different in the form wrapped around.
Due to such a difference, the shape of the loop may be slightly different, of course, and the skew correction may be insufficient at the time of pulling out with the registration roller pair after skew correction, or a new skew may occur. Could also cause

For these reasons, it has been sufficiently considered that skew may occur in a double-sided original even if the skew is adjusted for a single-sided original.

In the conventional document processing apparatus, as shown in FIG. 11, the reversing roller 104, the roller 105, the guide plate 106 around the roller 105, that is, one end of the paper path is moved left and right, and the position of the paper path is set to the front side. There is a document in which the skew of a double-sided original is adjusted by gradually changing from the rear side to the rear side.
That is, when the document is conveyed around the reversing roller,
By utilizing the fact that the paper is conveyed while being pressed to the outside of the bent paper path by the waist of the paper, the shaft center of the reversing roller 104 is slightly displaced from the direction orthogonal to the paper conveyance, and the paper on the front side and the paper on the back side are moved. The aim is to reduce the skew by changing the path length.

However, since this method does not actively form a loop, various factors such as a difference in the stiffness of the paper depending on the paper type and a change in the sliding load depending on the paper size can be considered. However, there is a defect that even if skew correction is possible for the original document, it is not compatible with other types of documents.

[0009]

According to the present invention, the document leading end abutting portion for correcting the skew of the document is provided at a plurality of locations, the correction location is selected by the document transport mode, and the plurality of locations are selected. By making it possible to adjust at least one of them independently, it is possible to provide a stable image in which skewing is suppressed for both single-sided originals and double-sided originals. Further, even in the case of a special transport mode such as thick paper, the optimum skew feeding correction method can be selected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a double-sided document feeder according to an embodiment of the present invention. The structure will be briefly described. Reference numeral 1 denotes a document tray on which an operator places a document s. Reference numeral 2 denotes a document stopper to which the front end of the document is abutted. A half-moon roller 3 separates the leading edge of the document and conveys the bottom sheet of the document. Reference numeral 4 denotes a weight, which falls when the original does not easily enter the separating portion and is pressed from above the half-moon roller 3 to assist the original conveyance. 5
Is a separation control plate that prevents the stack of documents from entering. 6
Is a paper feed roller, which cooperates with the following pair of separation rollers 7 and 8 and a separation belt 9 to separate the lowermost document from the document stack. The tip of the upper guide 10 has a registration roller 11 and a reversing roller 1.
The document is guided so that the original easily enters the resist nip formed by 2. 13 is an inner guide plate, 14
Are medium guides, each of which forms a conveyance path for a document and guides the document onto the platen 15. Drive roller 16, tan roller 1
The original is conveyed onto the platen 15 by the conveyor belt 18 stretched between the rollers 7 and the roller 19 which is pressed from the rear surface thereof, and stops. After the copying is completed, the conveyor belt 18 is reversed, and the original is scooped up by the jump table 20 and the lower guide 21 and the middle guide 1
The sheet is re-loaded on the tray 1 by the discharge roller pair 24, passing through the path formed by 4 and further between the opening / closing guide 22 and the reversing roller 12, the upper part of the flapper 23, and the upper part of the upper guide 10.

During both sides, the flapper 23 is deflected so that the original document passes under the flapper and is conveyed again onto the platen by the registration roller 11 and the reversing roller 12.

Next, a skew correction method will be described.
(FIG. 1) In the case of a single-sided original, the pre-registration sensor is set just before one original separated by the paper feed roller 6 and the separation belt 9 enters the nip of the registration roller 11 and the reversing roller 12 (hereinafter referred to as the registration nip). The tip is detected at 25,
After the leading edge reaches the resist nip and is abutted, the paper feed roller 6 is rotated and stopped only by forming a certain loop based on the previous detection. Inner guide plate 1 at this point
A stable loop is formed in the space formed by 3 and the upper guide 10, and the deviation between the front and the back when the resist nip enters is corrected.

In the case of a double-sided original, it is corrected once as in the case of the single-sided original and then fed onto the platen 15. Then, the conveyor belt 18 is rotated in the reverse direction to convey the document in the left direction. The leading edge of the document is the reverse roller 12 and the lower guide roller 2.
The tip is detected by the reversing sensor 27 immediately before entering the nip with 6 (hereinafter referred to as the second resist nip), and the tip is the second
After reaching the resist nip and hitting the resist nip, a certain loop is formed based on the previous detection.
Turn to stop. At this point, a stable loop is formed in the space formed by the lower guide 21 and the middle guide 14, and the deviation between the front and the back when the second resist nip enters is corrected.

Next, a method for adjusting the skew feeding will be described.

First, in the case of a single-sided original, an explanation will be given with reference to FIG. There is a mounting hole 28 on the image forming apparatus side, and legs 29 on the document conveying apparatus side are inserted to position the both. The bracket 30 and the mounting leg 29 on the side of the carrying device are fixed by a step screw 31, and the bracket 30 is movable in the direction of the arrow in the drawing by the long hole of the mounting leg with respect to the leg. Further, the bent portion 30a of the bracket and the leg 29 are fixed to each other at a constant interval by an adjusting screw 32 and a nut 33. It is possible to change the relative position of the bracket 30 and the leg 29 by moving the screw and nut.

FIG. 2 is a top view of the transport device, and the mounting portions for the image forming device are provided at two locations A and B. The adjustable mounting portion described above is provided on the B side, and the A side is completely fixed. The arrow direction in FIG. 3 described above coincides with the arrow direction in FIG. Now, assume that the one-sided original is skewed clockwise on the platen as shown in FIG. As an adjusting method in this case, the skew on the platen is adjusted by adjusting the relative position of the bracket to the leg in the right direction of the arrow in FIG. 3, that is, in the upward direction of the arrow in FIG.

After the adjustment of the one-sided original is completed, the adjustment of the two-sided original is performed. FIG. 4 shows a configuration for adjusting the skew feeding at the time of both sides, which is the essence of the present invention. The lower guide 21 is rotatable about a fulcrum 21a, and is biased by a lower guide spring 34 in the upward direction of the figure and counterclockwise about the fulcrum. Further, the plurality of lower guide rollers 26 are the lower guide roller shafts 35.
It is rotatable around and is pressed against the reversing roller 12 by the lower guide roller spring 36 to form a second resist nip. The fulcrum 21a of the lower guide is supported by a pin 38 protruding from the fulcrum plate 37, and the side plate 39 mounting hole 37a of the fulcrum plate 37 and the side plate through hole 39a of the pin 38 are provided in the reversing roller 1.
2 is a slot at right angles to the line connecting the centers of 2 and the lower guide roller 26. The fulcrum plate 37 and the lower guide 2
1 and 1 can be adjusted in the direction of the elongated hole as they are.

The above-mentioned adjustable structure may be provided on only one of the rear side and the front side of the lower guide. It is provided on the front side, which is usually easy to operate, and the rear side is adjustable to the front side. It is fixed by a pin connection with looseness.

With the above construction, the second resist nip line formed by the plurality of lower guide rollers 26 and the reversing roller 12 is aligned with the axis of the reversing roller 12 by adjusting the lower guide 21 and the fulcrum plate 37 left and right. It is possible to maintain the positional relationship of twist.

The skew feeding of a double-sided document can be adjusted by moving the lower guide 21 and the fulcrum plate 37 to the right in FIG. 4 if the front side of the document is moving forward.

Further, when the correction is performed by the second resist nip, the original is in a straight path under the conveyor belt 18 in the portion on the rear end side of the loop, so that a new skew after the skew correction is performed. Lines are unlikely to occur.

(Embodiment 2) In the above embodiment, the leading edge abutting portion on both sides of the original is formed as the second resist nip by the nip of the reversing roller and the lower guide roller, and skew feeding correction is performed. A document tip abutting portion may be provided on the right side of the glass. As shown in FIG. 5, platen glass 1
On the right side of 5, a glass presser 40 is attached to the upper surface of the glass with a length equal to or larger than the width of the original. As shown in FIG. 6, the glass edge of the glass top surface of the glass presser 40 is made of glass 1
It is attached in parallel with 5. During double-sided printing, the original is once fed to the right edge of the glass and abutted against the edge of the glass holder to correct skew. After that, the conveyor belt 18 rotates in the reverse direction and is conveyed to a predetermined position.

In this structure, the paper conveying path becomes long, the system speed is lowered, and the front end of the paper is abutted against the glass holder, so that the front end is apt to be damaged. This can reduce the impact on system speed reduction. The damage to the tip may be limited to the special mode such as the thick paper mode.
For thick paper, the conventional correction method for forming the tip abutting loop has difficulty in entering the nip and loops, making it difficult to remove skew and to prevent damage to the tip. It can be seen that it is.

Third Embodiment In the first embodiment, the second resist nip is formed by the nip of the reversing roller and the lower guide roller, and the entire lower guide is moved to adjust the nip line. That is, the nip between the plurality of lower guide rollers and the reversing roller is on a straight line. However, since the lower guide rollers are independently pressed against the reversing roller, each of the plurality of lower guide rollers may be movable left and right. For example, as shown in FIG. 7, it is assumed that there are six lower guide rollers 26 and nip of the reversing roller 12 for the original having the maximum paper width. Since it is more stable to perform correction with two roller nips that are as close to the paper width as possible, that is, the paper width, two nips at both ends of the six papers are adjusted for the maximum width original. However, in the case of a manuscript having a small paper width, if the manuscript device is set to the back side reference, it is conceivable that the front two of the six are not used and only the back four are conveyed. At this time, the skew correction is performed by the outermost roller nip in the small paper width, here, the third (12 ₃ ) and the innermost (12 ₆ ) roller nips from the front side. That is, the nippline can be changed depending on the size. However, in this case,
It is necessary that the nip line of the original (l ₁ ) having a small width is located on the downstream side of the nip line of the original (L ₁ ) having a wider width.

If the above conditions are not met,
In the case of a wide original, a means for releasing the central nip may be provided, or a wide nip may be provided on the upstream side.

[0026]

As described above, the document leading edge abutting portion for correcting the skew of the document is provided at a plurality of locations, the correction location is selected according to the document transport mode, and at least one of them is independently configured. By making the adjustment possible, it is possible to provide a stable image with no skew for a single-sided document, each paper type, and a two-sided document of each size.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a double-sided automatic conveyance device embodying the present invention,

FIG. 2 is a diagram showing a method of mounting and skew adjusting between the conveying device and the image forming apparatus,

FIG. 3 is a diagram showing a method for mounting and skewing between the conveying device and the image forming apparatus,

FIG. 4 is a diagram showing a configuration of an adjusting portion, which is the essence of the present invention,

FIG. 5 is an explanatory view of the second embodiment,

FIG. 6 is an explanatory diagram of a second embodiment,

FIG. 7 is an explanatory diagram of a third embodiment,

FIG. 8 is a sectional view of a conventional double-sided automatic transfer device,

FIG. 9 is a diagram showing a state at the time of conventional skew feeding correction;

FIG. 10 is a diagram showing a conventional skew correction state;

FIG. 11 is a diagram showing one of the conventional correction methods.

[Explanation of symbols]

 10 Upper Guide 11 Registration Roller 12 Reverse Roller 13 Inner Guide 14 Middle Guide 15 Platen Glass 18 Conveyor Belt 21 Lower Guide 22 Opening Guide 25 Pre-Registration Sensor 26 Lower Guide Roller 27 Inversion Sensor 37 Support Point Plate 37a Support Point Plate Mounting Hole (Long Hole) 38 pin 39 side plate 39a side plate hole (pincan including elongated hole)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiro Aoki 5540-11 Sakate-cho, Mizukaido-shi, Ibaraki Canon Aptex Corp.

Claims (1)

Claim: What is claimed is: 1. A double-sided document automatic conveyance device for automatically separating, conveying, reversing a single-sided document and a double-sided document, and sending the document to a predetermined position of an image forming apparatus to form an original document. An original document characterized in that a plurality of original document abutting portions for correcting the skew feeding are provided at a plurality of positions, a correction place is selected by an original document transportation mode, and at least one of the plurality of positions can be independently adjusted. Automatic transport device.