JP3009920B2 - Skew correction device for copy manuscript - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention corrects skew of a document to be circulated in a document transport device such as a copying machine or a printer capable of circulating and transporting a document. Skew correction apparatus for copy originals.

2. Description of the Related Art In a circulation type document conveying apparatus which repeatedly conveys a document to be copied a predetermined number of times to an exposure position and scans a predetermined number of images, the document is repeatedly circulated along the same path in the apparatus. There is a problem that the document being transported is skewed due to unevenness of the diameter and contact pressure of the transport roller in the circulation path, and image scanning is performed in a state where the document is bent.

For this reason, conventionally, the length of the right and left transport paths of the document is changed by moving the guide plate of the U-turn portion of the document forming a part of the document circulation path in an oblique direction corresponding to the skew of the document. There has been proposed an apparatus for correcting skew of a document.

[Problems to be Solved by the Invention] According to this conventional apparatus, it is possible to correct skew of a document, but in a device for handling a large document, a mechanism for moving a guide becomes large-scale. Additional means such as positioning of the guide plate are required.

Therefore, an object of the present invention is to provide an apparatus which can correct skew of a document with a simple configuration.

[Means for Solving the Problems] In order to solve the above problems, a circulation path for repeatedly transporting a document to an exposure position a predetermined number of times, a document U-turn portion forming a part of the circulation path, and a circulation path. And a detector for detecting left and right bending of a document to be arranged, wherein the U-turn portion is located opposite to a left portion and a right portion of the document, respectively, and is coaxially fixed and rotates. A step roller, first and second driven rollers provided so as to be able to contact and separate from the small-diameter roller and the large-diameter roller of the first step roller, respectively, and only one of the driven rollers is selectively contacted; And third and fourth driven rollers which are provided so as to be able to contact and separate from the small-diameter roller and the large-diameter roller, respectively, and selectively contact only one of them. And the driven roller And the first and fourth driven rollers or the second and third driven rollers are selectively switched to the step roller opposed thereto when the skew of the document is detected by the detector. It is characterized by acting.

[Operation] According to such a means, in the normal transport, the first
The third driven roller and the third driven roller respectively contact the small-diameter rollers of the first and second step rollers, and convey the document by the feed amount of the small-diameter rollers. If the document is skewed in one of the left and right directions, the driven roller contacting the small-diameter roller of the step roller facing the side lagging left and right separates, and instead, the driven roller corresponding to the large-diameter roller of the step roller concerned Abuts the original, and conveys the delayed side of the original by the feed amount of the large-diameter roller to correct the skew of the original.

[Example] Hereinafter, the present invention will be described with reference to the drawings.

In FIG. 1, reference numerals 11 to 15 denote driving rollers for conveying a document, and each driving roller has upper driven rollers 21 to 25.
And the lower driven rollers 31 to 35 are arranged so as to contact with appropriate pressure. Each of the drive rollers 11 to 15 conveys the document at a constant speed. Driving rollers 11-15 and upper and lower driven rollers 21-25 and 31-35 cooperating therewith
Are provided at positions suitable for forming the shortest circulation path when the A0, A1, A2, A3, and A4 size documents are circulated and sent in the longitudinal direction, respectively, and each size of the usable document size Is formed. 41 to 45 are drive rollers
Fingers provided adjacent to each roller corresponding to each of 21 to 25, and each finger is provided so as to be independently movable, and is usually located at a position not obstructing the upper conveying path 50. However, during operation, it moves across the upper transport path 50 to change the traveling direction of the transported document.
Numerals 51 to 55 are guide members for guiding the document whose path has been changed by the operation of the finger to the lower transport path 60 along the drive roller.

A document inserted from a document insertion port (not shown) is conveyed to the above-described circulation path by a feed roller 70, and is passed through a lower conveyance path 60 by drive rollers 11 to 15 and lower driven rollers 31 to 35 to expose a document at an original exposure position. Conveyed across 80. The document exposure position 80 is usually made of a transparent glass plate, and the document is conveyed (scanned) along its upper surface with the image surface facing downward.
As is well known, this document is exposed by an exposure lamp 81,
The light image is formed on the photosensitive drum 85 via the mirror 82, the lens 83, and the mirror 84, and a copy image according to the original is formed by the action of a well-known image forming unit disposed around the photosensitive drum 85. You.

The document that has been exposed is U-turned by the document U-turn unit 1 and guided to the upper transport path 50. In the case of a single copy, all the fingers 41 to 45 are at a position retracted downward from the upper conveyance path 50, and therefore, the original passes along the upper conveyance path 50 through the driving rollers 11 to 15 and the upper driven rollers 21 to 25. The sheet is conveyed outside by the discharge roller 90.

On the other hand, when copying a plurality of sheets from the same original, the original is circulated. In this case, the size of the conveyed document is detected by a size detection device (not shown) before the document is inserted into the circulation path. As a result, the finger 41 corresponding to the document size according to the detected size signal is output.
To 45 operate to form the shortest circulation path described above. For example, when the same document of A0 size is copied a plurality of times, the finger 41 operates and projects to the upper conveyance path 50 according to the detection signal of the size detection device. As a result, the image is scanned by the original exposure position 80, and the original sent to the upper transport path 50 through the U-turn section 1 is returned to the lower transport path 60 along the driving roller 11 according to the finger 41, and is again returned to the original exposure position. Conveyed to 80. This circulation is performed until the set number of copies is completed. When the exposure for the last copy is completed, the finger 41 retreats downward from the upper transport path 50,
The document is discharged by discharge rollers 90.

Similarly, if the document is of another size, the corresponding finger is activated to effect a similar circulation.

When the document circulates in circulating the document, a skew detector 100 is arranged facing the lower transport path 60 to detect the skew. In the figure, it is arranged between the lower driven rollers 34 and 35. The detector 100 has a pair of optical or mechanical sensors spaced apart in a direction substantially orthogonal to the direction of travel of the document so as to detect the passage of the leading edge of the document being transported on the left and right, respectively. Then, whether the document is skewed is detected by comparing the time when the document passes right and left. This detector is disabled in the case of one-sheet copying (without circulating feed).

To correct a skewed document, the document U-turn section
As particularly shown in FIG. 2 and FIG. 3, a first step roller 2 and a second step roller 3 having the same diameter are provided. The first step roller 2 and the second step roller 3 are located opposite to the left portion and the right portion of the document, respectively, and are coaxially fixed to the rotation shaft 4 and rotate normally. 2 and 3, the diameter difference between the small-diameter rollers 2a and 3a and the large-diameter rollers 2b and 3b of these step rollers is illustrated in an enlarged manner for convenience of explanation, and in practice, the diameter difference is small. For example, a difference in feed amount of several millimeters is formed between the leading edge of the document and the upper driven roller 25 from the position of driven rollers 5, 6, 7, and 8 to be described later.

The step roller is not limited to a roller in which a small-diameter roller and a large-diameter roller are integrated, but includes a combination of a separate small-diameter roller and a large-diameter roller.

Small diameter rollers 2a and 3a of first and second step rollers
The lower driven roller 10 is in contact with an appropriate pressure at a lower position thereof, and makes a document that has passed the document exposure position 80 make a U-turn upward along the guide member 9. The guide member 9 has a guide surface having a U-shaped cross section which is arranged at a distance from the first and second step rollers.

At the exit of the guide member 9, the first and second
The first and third driven rollers 5, 7 and the second and third rotatable rollers having substantially the same diameter so that they can be independently contacted and separated from the small-diameter rollers 2a and 3a and the large-diameter rollers 2b and 3b of the step rollers. Four driven rollers 6 and 8 are provided. First
The driven roller 5 and the second driven roller 6 are paired, and one of them is selected and comes into contact with the corresponding small-diameter roller 2a or large-diameter roller 2b. Similarly, one of the third and fourth driven rollers 7 and 8 is selected and comes into contact with the corresponding small-diameter roller 3a or large-diameter roller 3b. The document is conveyed between the step roller and the driven roller. In normal (not skewed) time, the first driven roller 5 and the third driven roller 7 are small-diameter rollers 2a,
In contact with 3a, the second driven roller 6 and the fourth driven roller 8 are separated from the large-diameter rollers 2b, 3b. The document sent by the lower driven roller 10 is sent along the guide surface of the guide member 9, and is fed by the first and second step rollers 2, 3 and the first and third driven rollers 5 and 7 by the same feed amount (left and right). It is sent to the upper conveying path 50 by the small-diameter rollers 2a, 3a).

During the circulating conveyance, when the skew of the document is detected by the skew detector 100, the driven rollers 5,
6 or 7, 8 is switched. For example, when the document is skewed so that the right side is delayed with respect to the left side of the document, as shown in FIG. 3, the third driven roller 7 separates from the small-diameter roller 3a, and instead, the fourth driven roller 8 becomes large-diameter. It comes into contact with the roller 3b. This switching is performed until the leading edge of the document reaches the driven roller 25. When the leading edge of the document reaches the driven roller 25, the original state is restored. In this way, when the document is skewed, the large-diameter roller 2b or
It is transported by the feed amount of 3b, thereby correcting skew.
At the time of this correction, since the document has slack in the gap between the guide member 9 and the step roller, the rear end of the document during image scanning is not pulled carelessly and does not shift.

In the above description, the driven roller is normally brought into contact with the small-diameter roller. However, the driven roller is normally brought into contact with the large-diameter roller, and the side that moves left and right when skewed may be switched to the small-diameter roller. .

[Effects of the Invention] As described above, according to the present invention, a conveying roller for making a U-turn of a document is constituted by a pair of left and right step rollers, and a driven roller cooperating with these rollers is a small-diameter roller of the step roller according to the skew of the document. The skew can be corrected by a simple configuration of selectively contacting any one of the large-diameter rollers.
In addition, since the right and left feed amounts of the original are directly changed by the roller unit that determines the original feed speed, the control is easy.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a skew correction apparatus according to the present invention, and FIGS. 2 and 3 are schematic views showing different operation states of the document U-turn section in FIG. Reference numeral 1 denotes a document U-turn portion, 2 denotes a first step roller, 3 denotes a second step roller, 4 denotes a rotating shaft, 5 denotes a first driven roller, 6 denotes a second driven roller. 7: Third driven roller, 8: Fourth driven roller, 9: Guide member, 11 to 15: Driving roller, 21 to 25: Upper driven roller, 31 to 35: Lower driven roller, 41-45 Fingers, 100 Skew detector.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiichi Asakura 4-2-1-3 Shimomaruko, Ota-ku, Tokyo Examiner, Katsurakawa Electric Co., Ltd. Atsushi Kurata (56) References JP-A-62-215449 (JP, A JP-A-1-145960 (JP, A) JP-A-61-44670 (JP, A) JP-A-57-93848 (JP, A) JP-A-60-178145 (JP, A) 136454 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 107 B65H 9/00-9/20

Claims (1)

(57) [Claims] 1. A circulation path for repeating a document a predetermined number of times and transporting the document to an exposure position, a document U-turn portion forming a part of the circulation path, and a detector for detecting a left or right bending of the document to be circulated. The U-turn portion is located opposite to the left portion and the right portion of the document, respectively, and is coaxially fixed and rotates first and second step rollers, and a small diameter of the first step roller A first roller and a second driven roller, which are provided so as to be able to contact and separate from the roller and the large-diameter roller, respectively, and selectively contact only one of them; and a small-diameter roller and a large-diameter roller of a second step roller. And third and fourth driven rollers which are provided so as to be able to contact and separate from each other and selectively contact only one of them, and the original is conveyed between these step rollers and the driven rollers. , The original by the detector A skew of a copy original, wherein when the skew is detected, the first and fourth driven rollers or the second and third driven rollers are selectively switched to act on opposing step rollers. Straightening equipment.