JPH0811632B2 - Automatic document feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic document feeder that separates and feeds stacked documents one by one toward a document processing unit such as a copying machine, a recording device, and a facsimile device. Regarding the sending device.

(Prior Art) An example of a conventional automatic document feeder will be described with reference to FIGS. 5 and 6. In FIG. 5, an original conveying belt 4 wound around a belt roller 2 and urged by a roller 3 is in sliding contact with the upper surface of the contact glass 1. Below the contact glass 1, a document exposure device is provided in a copying machine, and a document reading device (not shown) is provided in a facsimile device or a recording device. A document table 5 is arranged above the document transport belt 4, and a document table 5 having an image surface facing upward is provided on the document table 5.
Are stacked. The document table 5 is formed with a hole 5a through which a part of the peripheral surface of the calling roller 6 projects, and the roller is in contact with the lower surface of the lowest document. Manuscript table 5
The separation roller 7 is disposed at the tip of the. The separation roller 7 is rotatably supported by a support shaft 8. A brake member 9 made of rubber or the like is brought into contact with the upper peripheral surface of the separation roller 7. The brake member 9 has one end 9a locked to a hook 11 fixed to the cover 10, and the other end 9b locked to the cover 10 via a tension spring 12.

As shown in FIG. 6, pull-out rollers 13 and 13 are rotatably arranged on both sides of the separation roller 7 on the support shaft 8. The pull-out rollers 13, 13 are in pressure contact with the rollers 15, 15 fixed to the drive shaft 14. Drive shaft 14
Is driven to rotate in the document feeding direction by a drive source (not shown). The separation roller 7 is integrally formed with a gear 7a. On the other hand, the calling roller 6 is driven in the document feeding direction by a drive shaft 16 which is rotationally driven by a drive source (not shown). A gear 6a is integrally formed on the calling roller 6, and the gear and the gear 7a are connected by a gear 17. A document passage including guide plates 18 and 19 is provided between the pull-out roller 7 and the contact glass 1. A document sensor 20 for detecting a fed document is arranged in the document passage.

In FIG. 5, when a document feeding start signal is issued, the calling roller 6, the separation roller 7, the pullout roller 13, the roller 1
5, The document transport belt 4 is rotated in the direction of the arrow. The calling roller 6 moves the entire stacked originals to the left in the figure, and feeds the leading end between the rotating separating roller 7 and the braking member 9. The feeding force of the separating roller 7 acts on the lowermost original, and the braking force of the brake member 9 acts on the uppermost original, so that only the lowermost original is separated and the pullout roller 13 and the roller 15 are separated. Sent between and. When the document sensor 20 detects the leading edge of the document sandwiched between the roller pairs 13 and 15, the transmission of the driving force to the calling roller 6 is cut off based on the document detection signal. Therefore, the driving force to the separation roller 7 is also cut off. Therefore, after this, the document is fed by the pull-out roller 13 and the roller 15 and fed onto the contact glass 1 by the document transport belt 4. The separating roller 7 and the calling roller 6 rotate together with the fed document. The original conveyed on the contact glass 1 is reversely fed by the original conveying belt 4 which is rotated in the reverse direction, and its side edge is abutted against the original scale 21 in order to correct the stop position.

By the way, although the separation roller 7 is driven to rotate, a force acting on the original fed by the roller pair 13 and 15 is impeded by the brake member 9 to prevent the feeding. for that reason,
Although the document feeding force by the roller pair 13 and 15 is set to be relatively large, a slip may occur between the document and the roller pair 13 and 15. In order to eliminate this slip, it is sufficient to increase the pressure contact force of the rollers 15, 15, ... However, there is a problem that the operation for removing jammed paper becomes troublesome, and this cannot be increased so much. Then, since the roller 15 of the roller pair is driven, the roller 15 rubs against the image surface of the document to impair the image. In particular, when the original has a pencil-written image, the image damage is likely to occur.

Further, the document reading device, the exposure device, the developing device, the recording paper feeding device, and the like (not shown) are controlled in various operations on the basis of a signal for detecting the leading edge and the trailing edge of the document, that is, a signal for detecting the document length. It has become. Therefore, it is important for document processing to detect the correct document length. As a means for detecting the length of a document, one in which a pulse encoder is provided on the shaft 14 has been proposed. However, if slips occur on the roller pairs 13 and 15 that feed the separated documents, the rotation of the roller pairs 13 and 15 and the amount of movement of the documents do not match, and the correct document length cannot be detected. Occurs.

Further, as shown in FIG. 6, roller pairs 13 and 15 are arranged on both sides of the separation roller 7. If the outer diameters of the roller pairs arranged on both sides of the separation roller are different, there is a problem that the left and right feed lengths of the document are different in the transport direction and the document is skewed.

(Object) An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an automatic document feeder which can detect an accurate length without damaging an image and prevent skew.

(Structure) In order to achieve the above object, the present invention provides, in the automatic document feeder as described above, a first drive system for driving the separating roller in the document feeding direction and the pull-out roller for feeding the document. A second drive system for driving in the direction, and when the document is detected to be sandwiched between the pull-out roller and the pinch roller, the clutch means for releasing the driving force to the separation roller is driven by the first drive system. It is characterized by being provided in the system. A first drive system that drives the separation roller in the document feeding direction; and a second drive system that includes a support shaft that rotatably supports the separation roller in the document feeding direction and drives the pullout roller. One of a plurality of pinch rollers, which is provided between the support shaft and each of the pullout rollers, and which transmits a rotation of the support shaft in the document feeding direction to each of the pullout rollers, and one of a plurality of pinch rollers. And a pinch roller support shaft that rotatably supports another pinch roller, and drives the separation roller when it is detected that the document is nipped between the pullout roller and the pinch roller. It is characterized in that clutch means for releasing the force is provided in the first drive system.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments. The members having the same functions as those of the example shown in FIG. 5 are given the same reference numerals.

In FIG. 1, a gear 31 is fixed to a shaft 30 of the belt roller 2 around which the document conveying belt 4 is wound. Gear 31
Engages with a gear 33 fixed to a shaft 32. A gear 34 fixed to the shaft 32 meshes with an output gear 36 of a drive motor 35 as a drive source. A gear is attached to one end of the shaft 32 via a one-way clutch (drive transmission direction will be described later) 37.
38 are provided. The gear 38 has a calling roller support shaft.
The gear 40 fixed to 39 is meshed. The call roller 6 and the gear 44 are supported on the call roller support shaft 39 via one-way clutches 41 and 42 that transmit only rotation when the shaft is driven to rotate in the document feeding direction (first). 2 (see (a), (d)). Gear 44 has idle gear 17
Are in mesh. This idle gear 17 is the separation roller 7
Meshes with a gear 7a that is integral with. The separation roller 7 is supported by a support shaft 49 via a one-way clutch 48 (see FIG. 2 (b)). The one-way clutch 48 is the separation roller 7
The rotation of the support shaft 49 after the transmission of the driving force to the separating roller 7 is stopped. A brake member (see reference numeral 9 in FIG. 5) is brought into pressure contact with the separation roller 7.

A gear 50 meshing with the gear 38 is fixed to the end of the support shaft 48. Pull-out rollers 51 and 52 are provided on both sides of the support shaft 49 of the separation roller 7. The pull-out rollers 51, 52 are support shafts 4 that rotate in the document feeding direction.
Support shaft via one-way clutches 53, 54 that transmit the rotation of 9
It is attached to 49 (see FIG. 2 (a)). A pinch roller 56, which is in contact with the pull-out rollers 51, 52, is fixedly supported on a pinch roller support shaft 55 arranged in parallel with the support shaft 49. The pinch rollers 56, 56, ... are pressed against the pull-out rollers 51, 52 by means not shown in the drawing, and rotate following the rollers 51, 52.

The separation roller 7 includes a drive motor 35, gears 38 and 40, and a support shaft.
It is driven by a first drive system connected to 39, gear 44, idle gear 17, and gear 7a. The first drive system is provided with an electromagnetic clutch 57 as a clutch means for connecting and disconnecting the support shaft 39 which is divided into two in the longitudinal direction. The electromagnetic clutch 57 is activated by a signal when the document sensor 20 (see FIG. 5) detects the leading edge of the document, and cuts off the driving force to the separation roller 47. Pullout rollers 51,5
The second motor 2 is driven by a second drive system which is connected to the gears 38 and 50, the pull-out roller support shaft 49, and the one-way clutches 53 and 54 from the drive motor 35.

The operation of the embodiment configured as described above will be described with reference to FIGS. 1 and 5. When the document feed signal is issued,
The drive motor 35 rotates in the document feeding direction, and the gears 36, 34, 3
The original conveying belt 4 is connected via the gears 3 and 31, the separation roller 7 and the calling roller 6 are connected via the first drive system connected from the gear 36 to the gear 7a, and the second connecting the gear 36 to the one-way clutches 53 and 54. The pull-out rollers 51, 52 are rotationally driven in the document feeding direction via a drive system. For the originals stacked by the rotation of the calling roller 6, the leading end of the original is braked by the brake member 9.
And the separation roller 7 are allowed to enter the wedge-shaped space. Then, the lowermost original that receives the feeding force by the separating roller 7 and the pull-out rollers 51 and 52 that are respectively driven is separated from other originals that are being braked by the brake member 9. The separated document is fed toward the contact glass 1 by the feeding force of the separating roller 7, the pullout rollers 51, 52 and the pinch roller 56. When the leading edge of the document is detected by the document sensor 20, the electromagnetic clutch 57 is turned off by this detection signal, and the drive force transmission to the separation roller 7 by the first drive system is cut off. After that, the separating roller 7 and the calling roller 6 rotate together with the fed document. At this time, the document is fed while rubbing the brake member 9 by the pull-out rollers 51, 52 driven by the second drive system and the pinch rollers 15, 15 ... It Therefore, a force may be applied to the original document in a direction that hinders its feeding, and slip may occur between the original document and the pullout rollers 51 and 52.
However, the pinch rollers 15,1 that are in contact with the image surface of the original
Since 5 ... is accompanied by the manuscript to be fed,
There is no slip between the pinch roller and the original, and there is no image damage. Further, the rotational force of the support shaft 49 that is rotationally driven in the document feeding direction is not transmitted to the separation roller 7 by the action of the one-way clutch 48.
Therefore, since the separation roller 7 that stops the documents other than the fed document with the brake member 9 cannot be rotated, the stopped document is not advanced.

When the document is fed onto the contact glass 1, the drive motor 35 is de-energized, and the document conveying belt 4 for reversing the motor 35 is driven in the direction indicated by the arrow a. As a result, the document is abutted against the scale 21. When the drive motor 35 rotates in the reverse direction, the shaft 32 rotates in the direction opposite to the document feeding direction, but the rotation of this shaft is not transmitted to the first drive system and the second drive system by the action of the one-way clutch 37. That is, since the reverse rotation of the drive motor 35 at the time of document positioning is not transmitted to the calling roller 6 and the separation roller 7, the document on the document table 5 is not moved in the opposite direction, and its damage is prevented.

Next, referring to FIG. 3, another invention will be described.
The feature of the present invention resides in that, in addition to preventing the document image from being damaged, the moving speed of the document fed by the pull-out roller can be accurately detected, and the same reference numerals are given to the components already described. stop.

3 and 4, a pulse encoder 58 and a photo interrupter are provided at the end of the pinch roller support shaft 55.
A document length detecting means 60 including 59 is provided. The pulse encoder 58 has a shaft 55, as shown in FIG.
And slits 58a are formed at equal intervals in the circumferential direction. The photo interrupter 59 is composed of a light emitting element and a light receiving element. Pullout rollers 51,52
Of the pinch rollers 56, 56, ...
The pinch roller 56A that contacts the roller 51A is shown in FIG. 4 (e).
4, the other pinch roller 56B is attached to the support shaft 55 via the one-way clutch 61, as shown in FIG. 4 (f). The one-way clutch 61 acts in a direction to transmit the rotation of the pinch roller support shaft 55 to the roller. On the other hand, the pullout rollers 51A, 51, 51, ...
The outer diameter of the roller 51A is the largest. Since the pull-out roller (51) cannot be processed coaxially due to the assembling relationship, the pull-out roller (51) has a difference in outer diameter in the axial direction.
This difference in roller diameter causes skew of the document. Therefore, each pull-out roller 51 acts on the one-way clutch 53, (5
4) is pivoted through. Therefore, the fed document is moved in accordance with the rotation of the pullout roller 51A having the largest diameter, and the skew is eliminated. It should be noted that, unlike the example shown in the drawing, the position where the pull-out roller having the maximum diameter is arranged is effective for skew prevention if it is as close as possible to the central portion of the fed document.

The pinch roller 56A fixed to the support shaft is in contact with the pullout roller having the largest diameter.
It is 51A. That is, the fed document depends on the rotation speed of the pull-out roller 51A, and the pinch roller 56A
Will rotate following this document. Therefore,
The pulse encoder 58 rotates substantially integrally with the pinch roller 56A that rotates along with the document that is actually moving, and the document length detection means 60 detects the correct document length. It will be. When feeding documents with the pull-out roller and pinch roller, use the pinch rollers 56B and 56B.
The rotation of the pinch roller 56A, which rotates following the document, is transmitted via the support shaft 55 to rotate and feed the document.

(Effect of the Invention) As described above, according to the present invention, the pull-out roller is brought into contact with the surface opposite to the image surface of the original, so that even if slip occurs between the pull-out roller and the original, the original image Is not damaged. Further, since one of the pinch rollers is fixed to its support shaft and the other roller is made rotatable, the accurate length of the original can be detected, and accurate processing can be performed according to the length and moving speed of the original.

[Brief description of drawings]

1 is a front sectional view showing an embodiment of the first invention, FIG. 2 (a) is a side view showing a one-way clutch provided on a gear 38, and FIG. 2 (b) is a separation roller and its side. FIG. 2 (c) is a side view showing the clutch, FIG. 2 (c) is a side view showing the pull-out roller and its clutch, FIG. 2 (d) is a side view showing the one-way clutch provided on the gear 44, and FIG. FIG. 4 (a) is a side view showing a one-way clutch provided on the gear 38, and FIG. 4 (b) is a side view showing a separating roller and its clutch. FIG. 4 (c) is a side view showing the pullout roller and its clutch, and FIG. 4 (d).
Is a side view showing the one-way clutch provided on the gear 44, FIG. 4 (e) is a side view showing the pinch roller fixed to the pinch roller support shaft, and FIG. 4 (f) is rotating on the pinch roller support shaft. FIG. 4 (g) is a side view showing a pulse encoder of the document length detecting means, and FIG. 5 is a side view showing an automatic document feeder to which the present invention is directed. FIG. 6 is a plan view showing a conventional structure. 1 …… Contact glass, 5 …… Original table, 7 ……
Separation roller, 9 ... Brake member, 49 ... Support shaft, 51,5
1A, 52 …… Pullout roller, 53,54 …… One-way clutch, 55 …… Pinch roller support shaft, 56A, 56 …… Pinch roller, 57 …… Clutch means.

Claims (2)

[Claims] 1. A separating roller, which is rotatably provided with a brake member for preventing the movement of an original document, which is pressed against the brake member.
The separation roller has a substantially same outer diameter and is provided coaxially with the separation roller, and a pinch roller abutting the pullout roller and driven to rotate. An automatic original that separates the lowest original among a plurality of originals stacked on the original table by the brake member and the separating roller, and then reverses the pullout roller and the pinch roller to feed the original toward the contact glass. The feeding device includes a first drive system for driving the separation roller in the document feeding direction and a second drive system for driving the pullout roller in the document feeding direction, and the pullout roller and the pinch roller. When it is detected that the document is nipped, the clutch means for releasing the driving force to the separation roller is provided in the first drive system. Automatic document feeder and butterflies. 2. A separating roller, which is rotatably arranged and is pressed against a brake member for preventing movement of a document.
A plurality of pull-out rollers that have substantially the same outer diameter as the separation roller and are coaxial with the separation roller and are provided on both sides of the separation roller; and a pinch roller that abuts on the pull-out roller and is driven to rotate. Of the plurality of originals stacked with the image surface facing upward, the lowest original is separated by the brake member and the separation roller, and then inverted by the pullout roller and the pinch roller to form a contact glass. In an automatic document feeder for feeding toward a document, the pull-out includes a first drive system for driving the separating roller in the document feeding direction, and a support shaft for rotatably supporting the separating roller in the document feeding direction. A second drive system for driving the rollers, and a support shaft and the pull-out rollers are provided between the support shaft and the pull-out rollers to rotate the support shaft in the document feeding direction. The pull-out roller and the pinch roller, and a one-way clutch that transmits to the outroller, and a pinch roller support shaft that fixes one of the plurality of pinch rollers and rotatably supports the other pinch roller. An automatic document feeder, wherein the first drive system is provided with clutch means for releasing the driving force to the separation roller when it is detected that the document is nipped.