JP2001238046A - Method for carrying original - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for automatically carrying originals by which more copies are read per unit time than in the conventional practice while having a configuration in which an original is once stopped to correct oblique feeding of the original. SOLUTION: The original D carried to an original reading part 12 from the nip parts of a roller pair 16 for correcting oblique feeding is accelerated up to a prescribed reading rate (V1) by the time when the front edge of the original D reaches a prescribed original reading position 26. The original 26 is accelerated up to a faster rate (V2) than the prescribed reading rate (V1) between the nip parts and the position 26 and is subsequently decelerated to the prescribed reading rate (V1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document conveying method attached to an image processing apparatus such as a copying machine, a scanner, and a facsimile and used for an automatic document conveying apparatus for automatically supplying a document.

[0002]

2. Description of the Related Art In an automatic document feeder attached to an image processing apparatus, a document is transported from a document feed tray to an image (document) reading position of the image processing apparatus and scanned by an optical system provided there. Thereafter, the document is discharged to the document discharge tray. As the optical system, a CCD arranged in a direction perpendicular to the document conveying direction is used. In such an automatic document feeder, it is desired to read as many documents as possible in a short time. However, in reality, the reading speed of the CCD is limited, so that the document feeding speed may be increased by a certain rate or more. Can not. Therefore, in order to improve the productivity by increasing the number of documents read per unit time, it is conceivable to shorten the document transport interval as much as possible.

[0003]

On the other hand, the above-mentioned automatic document feeder usually has a structure in which the leading edge of the original is parallel to the CCD reading line when the leading edge of the original passes through the original reading position. This prevents the CCD from reading oblique image information (rather than image information in a direction orthogonal to the leading edge of the document) due to the document passing obliquely with respect to the reading line. In particular,
A roller pair parallel to the reading line by the CCD is arranged upstream of the document reading position in the document conveying direction, the leading end of the document is brought into contact with the nip portion of the stationary roller pair, and then the roller pair is rotated. To feed the leading edge of the original parallel to the reading line. However, due to the structure in which the document is temporarily stopped, when a plurality of documents are continuously read, there is a limit to shortening the interval between the temporarily stopped document and the previously read document.

Accordingly, the present invention provides a document conveying method capable of reading a larger number of sheets per unit time as compared with the related art while having a configuration in which the document is temporarily stopped in order to correct the skew of the document. The purpose is to do.

[0005]

According to a first aspect of the present invention, there is provided a document conveying method according to the present invention, wherein a document fed from a predetermined reference position is moved such that the leading end of the document reaches a predetermined document reading position. In the document conveying method, the document is accelerated to a predetermined reading speed (V ₁ ) during the period, the document is read from the reference position to the document reading position at the predetermined reading speed (V ₁ ).
It accelerates to a higher speed (V ₂ ) and then decelerates to the predetermined reading speed (V ₁ ).

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Automatic Document Feeder An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram of an automatic document feeder according to the present invention. The automatic document feeder 1 is arranged on an image processing device (for example, a copying machine, a facsimile, a scanner) not shown.

(2) Paper feed section The automatic document feeder 1 has a document supply tray 2 on which documents D can be stacked. At the end of the document supply tray 2 on the downstream side in the document supply direction (the direction of the arrow 4), a paper supply unit 6 for supplying the documents stacked on the document supply tray 2 one by one is provided.

The paper feed unit 6 is rotatably provided with a document supply roller 8 that comes in contact with the uppermost document D stacked on the document supply tray 2 and feeds the document. On the downstream side of the document supply roller 8 in the document feeding direction, a separating roller pair 10 rotatable in the illustrated direction is provided to prevent simultaneous feeding of a plurality of documents. On the downstream side of the separating roller pair 10 in the document conveying direction, the separated document D
2, a U-turn passage 14 is provided. A first roller pair 16 for adjusting the document supply timing to the document reading unit 12 is provided at an end of the passage 14 on the downstream side in the document transport direction. One of the rollers of the first roller pair 16 is drivingly connected to a motor 18.

The motor 18 is a motor having an encoder that converts the rotation angle of the motor into an output pulse and sends the output pulse to the controller 19. The controller 19 counts the number of pulses corresponding to the rotation angle of the first roller pair 16 and controls the power supply 20 for the motor 18 based on the counted number, so that the rotation speed of the motor 18 can be changed. It is.
According to this configuration, the first roller pair 16
The moving distance of the document D from the nip portion (the leading end position of the document D) can be obtained. In the present embodiment, each of the above-described and later-described rollers is a controller 1
The rotation / stop is controlled by 9, but this is not specifically described in this description unless necessary.

A transport roller pair 21 is provided between the separating roller pair 10 and the first roller pair 16, whereby
The document D is transported by the transport roller pair 21, and the leading edge of the document abuts on the upstream side of the nip portion of the first roller pair 16 in the document transport direction to correct the skew (that is, the document forms a loop, As a result, the leading edge of the document is adjusted perpendicular to the document transport direction.). This transport roller pair 2
One of the rollers 1 is drivingly connected to a motor (not shown). Further, a sensor 22 for detecting that the leading end of the document D is located in the nip portion is disposed near the upstream side of the nip portion of the first roller pair 16 in the document transport direction. The motor drive power supply 20 is activated in response to a detection signal from the controller.

(3) Document Reading Unit The document reading unit 12 is provided with a substrate 23 made of a transparent material such as glass, and is disposed on the upper side of the drawing of the substrate 23 so that the document D can pass between the substrate 23 and the substrate 23. A backup member 24 is disposed with a gap between the backup member 24 and a CCD 26 disposed below the transparent substrate 23 in the drawing and having image pickup devices arranged in the front and back directions of the paper surface of FIG. The CCD 26 is
A signal corresponding to the image information of the document D transported between the substrate 23 and the backup member 24 is transmitted to an image processing device (not shown).

First roller pair 1 with document reading section 12 interposed therebetween
6, the document D that has passed through the document reading unit 12 is
A second pair of rollers 32 for feeding the sheet to the sheet discharge path 28 or the intermediate path 30 is provided. Document D passing through document reading unit 12
In order to stabilize the speed of the second roller pair 32, one of the rollers of the second roller pair 32 is connected to the motor 18 connected to one of the rollers of the first roller pair 16, whereby the first roller It rotates in synchronization with the roller pair 16. A first switching claw 34 is provided in the vicinity of the nip portion of the second roller pair 32 on the downstream side in the document transport direction in order to switch the feeding to either the paper discharge passage 28 or the intermediate passage 30.
Is provided. The switching claw 34 is movable between a solid line position and a dotted line position.
When the document D sent from the nip portion 2 is guided to the paper discharge path 28, the document D is set to a solid line position, and when guided to the intermediate path 30, the document D is set to a dotted line position.

(4) Document Resupply Unit In order to read a two-sided document, the automatic document feeder 1 supplies a document to the document reading unit 12 with the surface opposite to the surface read first down. It has a supply unit 36. In the document resupplying section 36, near the end of the intermediate path 30 on the downstream side in the document conveying direction, the document D guided to the intermediate path 30 by the first switching claw 34 set at the dotted line position is placed in the first path. A first pair of reversing rollers 42 is provided to guide the reversing passage 40 and to send it out of the first reversing passage 40. Either one of the first pair of reverse rollers 42 is drivingly connected to a motor (not shown) that can rotate forward and reverse, and passes the original D through the nip during the forward rotation. It is taken into the reversing passage 40 and the first rotation is performed
From the reversing passage 40.

On the opposite side of the first reversing path 40 with respect to the first reversing roller pair 42, a re-supply path 44 for reversing the original D up and down and supplying the original D to the original reading section 12 again is provided.
Roller pair 16 is formed.

A second switching claw 46 is provided near the nip portion of the first reversing roller pair 42 on the side of the intermediate passage 30. The switching claw 46 is movable between a solid line position and a dotted line position, and is set at the solid line position when guiding the document D passing through the intermediate passage 30 to the nip portion of the first reversing roller pair 42. When the document D sent from the first reversing path 40 through the nip portion is guided to the re-supply path 44, the original D is set to a dotted line position.

(5) Paper discharge unit The original D guided to the paper discharge passage 28 by the first switching claw 34 set at the solid line position is the paper discharge unit 48. In the case of a two-sided original, the original is turned upside down, and the original discharge tray 52 is provided via a pair of discharge rollers 50 provided close to the downstream end of the discharge path 28 in the original discharge direction. The paper is ejected.

More specifically, a third switching claw 54 is provided in the middle of the paper discharge passage 28 to advance and retreat to the paper discharge passage 28. The switching claw 54 is movable between a solid line position for guiding the document D guided to the paper discharge passage 28 to the document discharge tray 52 as it is and a dotted line position for guiding the document D to the intermediate passage 56. is there.

In the vicinity of the end of the intermediate passage 56 on the downstream side in the document conveying direction, the document D guided to the intermediate passage 56 by the third switching claw 54 set at the dotted line position is connected to the second reversing passage 5.
A second pair of reversing rollers 60 are provided for guiding the reversing roller 8 and feeding it out of the second reversing passage 58. One of the rollers of the second pair of reverse rollers 60 is drivingly connected to a motor (not shown) that can rotate forward and reverse, and passes the document D through the nip portion during the forward rotation to the second direction. It is taken into the reversing passage 58 and the second reversing passage 5
8 to send out.

Between the vicinity of the end of the intermediate passage 56 on the downstream side in the document conveying direction and the vicinity of the end of the discharge passage 28 on the downstream side in the sheet discharging direction, the document sent out from the second reversing roller pair 60. A U-turn path 62 is formed for turning D upside down and supplying it to the document discharge tray 52.

A fourth switching claw 64 is provided in the vicinity of the nip portion of the second reversing roller pair 60 on the side of the intermediate passage 56 to advance and retreat to the U-turn passage 62. The switching claw 64 can move between a solid line position and a dotted line position, and moves the document D passing through the intermediate passage 56 to the second reversing roller pair 60.
When the document D sent from the second reversing path 58 through the nip is guided to the U-turn path 62, the position is set to a dotted line.

(Document Transfer Operation) The document transfer operation of the automatic document feeder 1 having the above configuration will be described. Document D is
As shown in the figure, it is arranged on the document supply tray 2. At this time, in the case of a single-sided original, the original is placed with the original side facing up, and in the case of a double-sided original, the original to be read is placed with the original side facing up. In this state, when a document supply command is issued from the image processing apparatus to the automatic document feeder 1, the document supply roller 8 rotates in contact with the upper surface of the uppermost document D, and sends the uppermost document D rightward in the drawing. At this time, the document below the uppermost document D may be supplied to the right side in the drawing due to friction. However, the originals other than the uppermost original are separated from the uppermost original by rotation of the lower separating roller 10 in the counterclockwise direction, and supply from here on is prohibited. The document D that has passed through the nip portion of the separation roller pair 10 is sent into the passage 14, and subsequently conveyed in the passage 14 by the conveyance roller pair 21, and is placed at the nip portion of the stationary first roller pair 16. Abut on each other to correct skew.

The controller 19 detects a signal from the sensor 22.
In response to the output signal, the motor 18 and the transport roller 21 are driven.
Start the motor (not shown). As a result, skew correction
The original D is transferred to the first roller pair 16 and the transport roller pair.
The document reading unit 12 is rotated by the
Will be sent out. At this time, conventionally, the speed of the original D is
2 (a). Specifically,
1 will be described.
Is accelerated by receiving the conveying force, and the predetermined speed V ₁(this
Depends on the reading speed of the CCD 26. ) Reached
Later, this speed V₁From the start of feeding while being conveyed by
T₁After a time, the leading edge of the document arrives at the reading position by the CCD 26.
Has reached.

On the other hand, in the present invention, as shown in FIG.
₂ (> V ₁ ) once (0-T ₂ ), and this speed V ₂
There is a fixed time (T ₂ ~T ₃₎ maintenance. Thereafter, the document D is decelerated to the speed _{V 1 (T 3 ~T 4)} , the leading edge of the document D at this speed V ₁ is reaches the reading position. In this case, the time T ₅ to the original tip from feeding start reaches the reading position shorter than T _1, the time difference (T ₅ -T ₁₎ is read time per only be shortened. In other words, the number of documents to be read per unit time can be increased.
Further, by counting the number of pulses proportional to the number of rotations of the motor 18 which is drivingly connected to one of the rollers of the first roller pair 16, the acceleration time (0 to T ₂ ) and the time for maintaining the speed V ₂ (T _{2 to} T ₃ ), the deceleration time (T _{3 to} T ₄ ), and the like can be managed, so that the controller 19 can reliably switch the speed.

The graph of FIG. 2B is an example of the speed control of the document D according to the present invention, and the first roller pair 1
Before reaching the document reading position from 6, if transport the document D at a faster than the rate at the time of reading speed, since the original tip can reach faster the document reading position from the time T _1, the advantages of the present invention Is possible.

Returning to FIG. 1, when reading only one side,
When the rear end of the document D has passed the reading position, the first and second roller pairs 16 and 32 are temporarily stopped. When the rollers stop, the number of pulses proportional to the number of rotations of the motor 18 drivingly connected to one of the rollers of the first roller pair 16 (this corresponds to the moving distance of the leading end of the document) reaches a predetermined value. It will be done at the time. Subsequently, the second document D is transported until the leading end thereof contacts the nip portion of the first roller pair 16, and the controller 19 receives the detection signal from the sensor 22 again, and Rotate the roller pairs 16 and 32 (note that, for the feeding of the second document D, for example,
A sensor 66 is provided near the downstream side of the nip portion of the separating roller pair 10 in the document conveying direction.
Receives the detection signal transmitted by detecting that the rear end of the document D has passed, and starts feeding the second document D after a predetermined time has elapsed. ). At this time, the first and third switching claws 34,
Reference numeral 54 is arranged at a solid line position, and the first document D is discharged to the document discharge tray 52 through the paper discharge path 28 with the document face down. Subsequently, the second document D is also discharged onto the first document D in the document discharge tray 52 through the document reading unit 12 and the discharge path 28.

When reading both sides of a document, even if the rear end of the document D passes the reading position, the first and second roller pairs 1
When the document D is sent out from the nip portion of the second roller pair 32 without stopping the first and second switching claws 34 and 32, the first switching claw 34 is disposed at the dotted line position and the second switching claw 46 is disposed at the solid line position. Let it. Therefore, the document D is transferred to the intermediate passage 30.
, And then guided to the first reversing passage 40 by the forward rotation of the first pair of reversing rollers 42. At this time, the surface of the document already read faces downward. Then, manuscript D
When the vicinity of the rear end is sandwiched between the first pair of reversing rollers 42, the first pair of reversing rollers 42 rotates in the opposite direction. At this time,
The second switching claw 46 has been switched to the dotted line position, so that the document D is conveyed again to the first roller pair 16 through the resupply path 44.

Thereafter, the document D passes through the document reading section 12 while switching the speed in the same manner as described above, and the surface which has not been read first is read. When the rear end of the document D passes the reading position, the first and second roller pairs 16 and 3
Stop 2 once. Subsequently, the second document D is transported until the leading end thereof contacts the nip portion of the first roller pair 16, and the first and second roller pairs 16, 32 are rotated again.

At this time, the first switching claw 34 is positioned at the solid line,
The third switching claw 54 is switched to the dotted line position, and the fourth switching claw 64 is switched to the solid line position. After the document D passes through the intermediate passage 56, the second reversing roller pair 60 is rotated forward by the second rotation. To the reversing passage 58. At this time, the surface of the original that has been read first faces upward. Subsequently, when the vicinity of the rear end of the document D is sandwiched between the second pair of reversing rollers 60, the second pair of reversing rollers 60 rotates in the opposite direction. At this time, the fourth switching claw 64 has been switched to the dotted line position, so that the document D passes through the U-turn path 62 and
The document is ejected with the original surface read first down. Further, the second document D is also read by the document reading unit 12 and the intermediate passage 3.
0, the first reversing path 40, the re-supply path 44, and the document reading section 12, and after the both sides are read, the intermediate path 5
6. The document is discharged onto the first document D in the document discharge tray 52 through the second reversing path 58 and the U-turn path 62.

[0029]

According to the automatic document feeder of the present invention, the document is transported at the first transport speed until the leading edge reaches the vicinity of the image reading position, and then the second transport speed is lower than the first transport speed. It passes through the image reading position at the transport speed. Therefore, as compared with the related art, the time from the skew feeding correction roller (document conveying means) to the reading position is shortened, so that the distance to the document read earlier is shortened. That is, since the interval between documents can be reduced only by controlling the speed, the number of sheets read per unit time can be increased with an inexpensive configuration.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an automatic document feeder according to the present invention.

FIG. 2A is a graph showing conventional document speed control when a document is transported from a skew feeding correction roller pair to a document reading position. (B) A graph showing the speed control of the document according to the present invention when the document is transported from the skew feeding correction roller pair to the document reading position.

[Explanation of symbols]

1: automatic document feeder, 12: document reading unit, 16: first
Roller pair, 26: CCD, 32: second roller pair.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H076 AA58 BA24 BA36 BA41 BA42 BA49 BA57 BA58 BA68 3F049 AA10 EA10 EA12 EA17 LA02 LA05 LB02 5B047 AA01 BA01 BB02 CA08 5C062 AA02 AA05 AB17 AB32 AC02 AC12 BA04 5C07A NA

Claims (1)

[Claims] 1. A document transport method for accelerating a document sent from a predetermined reference position to a predetermined reading speed (V ₁ ) while the leading edge of the document reaches a predetermined document reading position. between the position to the document reading position, a document, and then accelerated to a faster rate (V ₂₎ than the predetermined reading speed (V _1), then to decelerate to the predetermined reading speed (V ₁₎ Characteristic document conveyance method.