JPH04101941A - Document feeder - Google Patents

Abstract

PURPOSE:To enable approach of a succeeding document to a preceding document by providing plural pressure rollers for pressing a feed belt along the document feed direction, and individually decreasing the pressing forces of the rollers in the order of array according to the size of a document when the preceding document is placed on a read position. CONSTITUTION:An endless document transport belt 35 is disposed above a transparent plate 24 of a reader, and plural pressure rollers 36a-36e are arrayed along the transport direction. A document is transported on the transparent plate 24 by the pressing force of the belt 35 and stopped at a read position 24a to be read. The next document is fed while the preceding document is stopped and stopped by the most upstream side roller 36a. In this case, as the dimension in the transport direction of the preceding document is reduced, the pressing force of the roller 36 corresponding to the trailing end is decreased. Accordingly, the succeeding document can approach the preceding document for such decrease so as to reduce the copying time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a document feeding device that is installed in a copying machine and sequentially feeds a plurality of sheet-like documents onto a document reading surface for reading exposure.

BACKGROUND OF THE INVENTION Conventionally, copying machines have tended to be equipped with a document feeding device that automatically feeds multiple sheet-like documents sequentially onto the document reading surface for the operator's convenience. be. The device reads and exposes original images of originals that are sequentially fed onto the original reading surface, and cooperates with a copying machine to realize double-sided copying, single-sided copying, etc.

FIG. 9 is a sectional view showing a simplified configuration of a typical conventional document feeding device 1. As shown in FIG. The document feeding device 1 is installed, for example, on the upper surface 3 of the electrostatic copying machine 2. A transparent plate 4 forming a document reading surface is fitted into the upper surface 3 of the body. A document d is fed onto the transparent plate 4 along a feeding direction 5 .

The document feeding device 1 includes a plurality of endless belts 8 wrapped around a pair of rollers 6.7 arranged along the feeding direction 5. Further, a plurality of press rollers 9a to 9e are sequentially arranged along the feeding direction 5 on the inner surface side of the belt, which is the lower beam portion of the endless belt 8 facing the transparent plate 4.

The documents d stacked and placed on the stacking table 10 are fed one by one along the feeding direction 5 from the upper side in the stacking direction by a paper feeding means (not shown), and are fed in a clockwise direction (see FIG. 9). ) is conveyed over the transparent plate 4 by a rotating belt 8 , and is brought to a reading position where the downstream end of the document in the feeding direction 5 abuts against the contact piece 11 . At this time, the press roller 9
a to 9e press the fed document d onto the transparent plate 4 via the belt 8, and bring the document d to the reading position.
prevents it from floating.

The document d brought to the reading position is scanned in the direction of arrow 15 by an optical reading means 14 including a light source 12, a reflecting mirror 13, etc., so that the document image is read and exposed.

For the document d that has been read and exposed at the reading position in this way,
The abutment of the abutment piece 11 is released by driving a solenoid (not shown), the belt 8 is rotated again, and the document is ejected to the document ejection table 17 via the transport light I@16. The above-mentioned feeding is performed sequentially for the originals d stacked on the original placing table 10.

Problems to be Solved by the Invention In such a configuration in which a plurality of original sheets are sequentially fed to a reading position, it is difficult to decide at what timing to feed the original that follows the previously fed original. It greatly affects the time spent on the entire copy.

FIG. 10 is a diagram for explaining problems caused by the conventional configuration. Please note that the reference code for the original that is fed in advance is dl.
d2 is the reference number for the document to be fed subsequently, and when relating the dimensions, the same reference number is given the subscript L (
The document d1, which is shown with a large size) and S (small size), which is fed in advance, is conveyed by the belt 8 to a reading position where it comes into contact with the contact piece 11. When the document d1 is conveyed to the read value 1, the belt 8 stops, and the optical reading means 14 reads and exposes the document d1. Using the time for reading and exposing, the document d2 to be fed subsequently is conveyed to the intermediate position 1 on the transparent plate 4 in advance.

By the way, in the conventional configuration, each press roller 9a
- 9e are not individually controlled, and the pressing forces on the belt 8 are all controlled to be the same. Therefore, to avoid floating at reading 1, all press rollers 9
a to 9d are pressed toward the transparent plate 4 via the belt 8, and as a result, the press roller 9 on the most upstream side in the feeding direction
On the downstream side in the feeding direction with respect to a, the belt 8 and the transparent plate 4 are pressed against each other with the document d1 interposed therebetween. During the reading exposure, the belt 8 is stopped, so only the conveying force from the paper feeding means of the document mounting table 10 acts on the document d2, and the belt 8 on the downstream side of the feeding direction of the press roller 9a - transparent. Board 4
In other words, during the reading exposure of the preceding document di, the subsequent document d2 reaches the standby position where the downstream end in the feeding direction reaches the press roller 9a on the most upstream side in the feeding direction. Feeding to the downstream side in the feeding direction from the above-mentioned position is not possible due to bending of the leading end or paper jam.

FIG. 10(1) shows a state in which a document dlL having a dimension la1 along the paper feeding direction 5 is conveyed to the reading position.

While the document dll is being read and exposed, the subsequent document d2L can be fed on standby to the press roller 9a. That is, the subsequent document d2L can be conveyed in advance by a distance of 1 cl on the transparent plate 4, and the document d
There is a gap of 1 bl between lL and original d2L. Therefore, when the document dll finishes its reading exposure and the belt 8 is driven again, the following document d2L is conveyed to the reading position by being conveyed by the dimension la1+interval 1bl.

FIG. 10(2) shows a state in which a document dlS having a dimension la2 along the feeding direction 5 is conveyed to the reading position.

Note that there is a relationship of ff1al>1a2 = (1). Even if the document d2S has the reduced size, in the conventional configuration, the subsequent document d2S can only be wait-fed up to the press roller 9a as described above. The distance lc2 for conveying the upper part in advance is lc 1 =1c2
... has the relationship (2). Therefore, the gap 1b2 between the original dlS-lS-original amount 25 is the large-sized original dl.
l.

For the said interval 1b,1 in d2L,! b1klb2
...has the relationship (3). However, the distance required to convey the following document d2S to the reading position after the reading exposure of the preceding document dlS is completed is the dimension 1a2+interval 1b2, which is the same as for the large-sized document d2L. In other words, since the waiting position for the subsequent document d2 is constant regardless of the different dimensions, the time spent to transport the reading position across multiple documents is the same regardless of the different dimensions of the documents. .

As is clear from FIG. 10, as the size of the document d decreases, the interval between the fed documents increases. If the interval can be reduced, the time it takes to convey the following document d2 to the reading position after the preceding document d1 will be shortened, and as a result, the time required to convey the following document d2 to the reading position between multiple sheets of documents will be reduced. This will significantly reduce the amount of time you spend.

Therefore, an object of the present invention is to provide a document feeding device that can significantly reduce the time required to feed a plurality of sheet-like documents onto a document reading surface with a simple configuration. be.

Means for Solving the Problems The present invention provides a belt for feeding a sheet-like original onto the original reading surface of a copying machine; a plurality of pressing rollers that press the document reading surface through the document reading surface, and when a previously fed document is placed on the document reading surface, The document feeding device is characterized in that the pressing force of the plurality of pressing rollers on the belt is individually reduced and controlled in the order of arrangement in accordance with the reduction in the dimension of the document to be fed along the feeding direction. be.

Function According to the present invention, the plurality of pressing rollers press the document fed by the belt onto the document reading surface via the belt. The pressing force is individually controlled according to the dimension along. In particular, when a previously fed document is placed on the document reading surface, the pressing force of a plurality of pressing rollers predetermined from the upstream side in the feeding direction on the belt is as follows:
Reduction control is performed individually in the order of arrangement in accordance with the reduction in the dimensions of the fed documents. Therefore, as the dimensions are reduced, the gap between the belt and the document placement surface on the upstream side in the feeding direction is widened, and the gap between the preceding document and the subsequent document that is waiting and fed in advance is increased. It can be significantly shortened.

That is, it is possible to significantly reduce the amount of time it takes to convey a subsequent document onto the document reading surface, and as a result, it is possible to significantly reduce the amount of time it takes to feed a plurality of documents.

Embodiment FIG. 1 is a sectional view showing a simplified configuration of a document feeding device 21 which is an embodiment of the present invention, and FIG. 2 is a transfer type electrostatic copying machine equipped with the document feeding device 21. 22 is a cross-sectional view showing a simplified configuration of FIG.

The document feeding device 21 is installed on the upper body surface 23 of the copying machine 22 . A transparent plate 24 made of hard glass or the like that forms a document reading surface is fitted into the upper surface 23 of the body, and the document image facing toward the inside of the body from a predetermined reading position 24 & on the transparent plate 24 is For example, it is optically scanned, read and exposed, and is copied onto recording paper P as described later. The document feeding device 21 is angularly displaceable, for example, around the axis of a rotating shaft (not shown) that is horizontal in FIG. 1, and the covering of the document feeding device 21 on the transparent plate 24 is released by the angular displacement. be able to. Thereby, a thick original such as a book can be placed on the transparent plate 24 and read and exposed.

Generally, as shown in FIGS. 1 and 2, the document feeder 21 is arranged to cover a transparent plate 24, and is used to carry sheet-like documents stacked on a document table 25. It is possible to perform one-sided copying or double-sided copying on the recording paper P by automatically feeding the sheets one after another and reading and exposing them.

The configuration of the document feeding device 21 will be described below with reference to FIG.

The original document mounting table 25 is provided on the upper right side of the machine body in FIG. The document mounting table 25 is provided with a pair of alignment plates 27 that face each other in the width direction perpendicular to the feeding direction 26 of the stacked documents.

The alignment plate 27 can be manually moved toward both ends in the width direction of the stacked document trays, and regulates the positions of both ends in the width direction of the document trays. Note that the matching plate 2
Due to the regulation in accordance with No. 7, the center position in the width direction of the stacked originals remains constant regardless of different sizes.

The document mounting table 25 is also provided with a size detector S1. In FIG. 1, the size detector S1 has a configuration of a pair of size detectors provided facing each other along the feeding direction 26. It consists of a claw member 100, etc. that protrudes toward the surface side. When the original is placed on the original placing table 25, the protruding claw member 1
00 is pressed by the original weight. In the pair of size detectors Sla and Slb, the claw member 1
By determining the combination of pressures 00, the dimensions along the feeding direction 26 of the original placed on the original placing table 25 can be approximately determined. Furthermore, the size detector S
Based on the combination of the detection result No. 1 and the regulating position of the alignment plate 27, the size of the document placed thereon can be determined. However, if the stacked manuscripts contain a mixture of different sizes, such as A4 size (Japanese Industrial Standards A row 4 size, hereinafter the same) and A3 size, not all sizes will be judged. , is set based on the combination of the pressing forces of the claw member 100.

Further, a document detector S2 comprising, for example, an optical detector is provided above the document tray placed above in the stacking direction. The document detector S2 determines whether or not a document is placed on the document table 25.

A paper feeding means 28 is arranged at the downstream end of the stacked originals in the feeding direction and on the upper side! be done. In Figure 1,
The paper feeding means 28 includes, for example, a roller 29,
It comes into contact with the top of the stacked originals in the stacking direction, and feeds the originals one by one from the top. Note that the paper feeding means 28 may have a structure other than the roller 29, and may be composed of, for example, suction conveyance means.

The document fed by the paper feeding means 28 is moved along the feeding direction 26 by the feeding rollers 30 and 31 to the feeding path 3.
2 and is transported onto the transparent plate 24. On the conveyance path 32, a sheet length detector S3 including, for example, a light emitting element S3a and a light receiving element S3b is arranged.

The sheet length detector S3 calculates the time during which the irradiation light from the light-emitting element S3a to the light-receiving element S3b is interrupted by the conveyed document sheet, and calculates the length of time from the conveyance speed of the document sheet set by the conveyance rollers 30, 31. Original feeding direction 26
Calculate the dimensions along. As a result, even if the size of originals of different sizes stacked on the original platen 25 cannot be determined by the size detector S1, the sheet length can be detected at the time the originals are conveyed onto the transparent plate 24. The dimension along the feeding direction 26 can be determined by the container S3.

On the upper side of the transparent plate 24, rollers 33 and 34 having axes along the width direction of the document tray are disposed in a pair along the feeding direction 26. A plurality of endless belts 35 are wound between the rollers 33 and 34.
A plurality of (five in this embodiment) press rollers 36a to 3 are provided on the inner surface side of the belt with respect to the lower rack portion 35a of 5.
6e are arranged in this order along the feeding direction 26. The press rollers 36a to 36e, which are pressing rollers, are
Press the belt 35 toward the transparent plate 24, and press the belt 35 toward the transparent plate 24.
5 to avoid loosening of the tension of the belt 35-
This prevents the original paper fed between the transparent plates 24 from floating.

In this embodiment, each of the press rollers 36a to 36
The pressing force of e on the belt 35 is individually controlled. In FIG. 1, a press roller 36a on the upstream side of the feeding direction 26,
36b is controlled by switching the pressing force against the belt 35 according to the dimension of the document to be fed along the feeding direction 26. On the other hand, regarding the remaining press rollers 36c to 36e, the belt 3
The pressing force on 5 is controlled in the same manner.

FIG. 3 is a side view showing a simplified configuration of the press roller 36c. Although FIG. 3 is described in relation to the press roller 36c, the press rollers 36d and 36e, which are controlled in the same way, also have a similar configuration. The press roller 36c is provided around a shaft portion 37 having an axis parallel to the width direction of the document to be fed, and both ends of the shaft portion 37 are rotatably supported by a support shaft 38. A connecting member 39 is connected to the support shaft 38, and a pressing coil spring 40 is wound between the connecting member 39 and the support shaft 38. The spring force of the spring 40 sets the pressing force of the press roller 36c against the belt 35 via the support shaft 38. In this way, the press rollers 36c to 36e press the belt 35 toward the transparent plate 24 with the same pressing force.

FIG. 4 is a front view showing a simplified configuration of the press roller 36a, and FIG. 5 is a side view showing a simplified configuration of the press roller 36a. Note that FIG. 4 corresponds to a sectional view taken along the section line N-IV in FIG. 1. Press roller 3
6a, a plurality of narrow rollers 361a to 364a (four in FIG. 4) are rotatably supported on a shaft portion 41 having an axis parallel to the width direction of the document to be fed. .

Connecting portions 42a extend radially outward from the rotation center of the shaft portion 41 from both ends of the shaft portion 41.

42b are connected, and the connecting parts 42a, 4
Rotating shaft parts 43a and 43b having an axis along the width direction are continuous to the other end part of 2b that is not connected to the shaft part 41. The rotational axes of the rotational shaft portions 43a and 43b'' are the same,
It is rotatably supported by side walls 44a and 44b provided on both sides, respectively, and supported by bearings 45a and 45b. A gear 46 is fixed to the rotating shaft portion 43a on the negative side, and the gear 46 meshes with a gear 47 that is rotationally driven by the motor M1.

Therefore, by driving the motor M1, the press roller 36a can be angularly displaced by the angle θ around the axes of the rotating shaft portions 43a and 43b. That is,
As shown in FIG. 5, the press roller 36a can move up and down between an upper position shown by a solid line and a lower position shown by a phantom line. When the press roller 36a is placed in the upper position, the pressing force on the belt 35 is controlled to be reduced, and on the other hand, when the press roller 36a is placed in the lower position, the pressing force on the belt is controlled to be increased. It turns out.

In this embodiment, the displacement θ is constant, so the pressing force of the press roller 36a on the belt 35 is 2.
Switched over stages. Further, the pressing force is adjusted by setting the lengths of the connecting portions 42a and 42b.

Further, a roller position detector S4 consisting of, for example, an optical detector is disposed near the press roller 36a. The roller position detector S4 is the press roller 36
The arrangement state of the upper position and lower position of a is detected from, for example, the amount of angular displacement of the gear 46.

Note that the configuration of the press roller 36b is also the same as that of the press roller 3.
The configuration is similar to that of 6a, and the pressing force on the belt 35 can be switched and controlled. In addition, press rollers 36a, 3
The configuration in which the belt 6b moves up and down to control the pressing force on the belt 35 is not limited to the configuration of this embodiment.

As described above, the document sheets sequentially fed from the document rack 25 are pressed and conveyed on the transparent plate 24 by the belt 35, and the downstream end of the document sheet in the feeding direction is on the downstream side of the transparent plate 24 in the feeding direction 26. It is conveyed to the reading position 24a where it comes into contact with the abutment piece 47 that is arranged to protrude at the end.

In this embodiment, the movable press roller 36
The set positions of a and 36b, that is, the pressing force against the belt 35, are individually set depending on the size of the document to be fed.

FIG. 6 shows press rollers 36a to 36e in this embodiment.
FIG. 3 is a diagram for explaining a setting operation. In addition, in FIG. 6, the reference symbol of the document fed in advance is Dl,
The reference mark of the document to be fed subsequently is D2, and when further associating the dimensions, the subscript L (first
Dimensions) 1M (second dimension) and S (third dimension) are shown.

In FIG. 6(1), Wl>111≧W with respect to the distances Wl and W2 between the press rollers 36a and 36b and the contact piece 47.
2...A document DIL having a feeding direction dimension 111 (first dimension) that satisfies the relationship (4) is shown being fed to the reading position 24a. At this time, the press rollers 36a and 36b are both placed in the lower position, and the pressing force is not controlled to be reduced.In the document feeding device 21, the preceding document DIL is fed to the reading position 24a and as described below. While the document is being read and exposed, so-called standby feeding is performed in which the subsequent document D2L is previously fed to just before the upstream end in the feeding direction of the preceding document DIL and held on standby. In FIG. 6(1), all the press rollers 36a to 36e press the belt 35, so that the gap between the belt 35 and the transparent plate 24 is smaller on the downstream side in the feeding direction than the press roller 36a on the most upstream side in the feeding direction. The document D2L is pressed against the document DIL, and as a result, the subsequent document D2L can be fed to the standby position 24b where the downstream end of the document D2L in the feeding direction reaches the press roller 36a. Feeding from the standby position 24b to the downstream side in the feeding direction is not executed due to a bend in the leading edge or a paper jam. Therefore, the interval f13 between the preceding original DLL and the waiting subsequent original D2L.
is the interval obtained by subtracting the dimension 111 from the interval W1,
After the reading exposure of the preceding document DIL is completed, the standby position 24b
The distance required to convey the subsequent document D2 located at the reading position 24a is the distance W1.

FIG. 6(2) shows the distance W2 between each press roller 36b, 36c and the contact piece 47. For W3, W2>121≧
W3...A document D'1M having a feeding direction dimension 121 (second dimension) that satisfies the relationship (5) is shown being fed to the reading position 24a. When it is determined that the dimension of the document D1 to be fed is the second dimension, the press roller 36a on the most upstream side in the feeding direction is moved upward! The pressing force on the belt 35 is controlled to be reduced. Therefore, the original DIM is transferred to the remaining press rollers 36b to 36e.
The press roller 36a is pressed and conveyed to the reading position 24a by the press roller 36a, so that the belt 35-
A gap is formed between the transparent plates 24. Therefore, the downstream end of the subsequent document D2M in the feeding direction is located at the press roller 36b.
It is possible to carry out standby feeding to the standby position 24b where it comes into contact with. That is, the interval 123 between the preceding original DIM and the waiting original original D2M is the interval obtained by subtracting the feeding direction dimension 121 from the interval W2, and the interval 123 is equal to the interval W2 minus the feeding direction dimension 121.
1.

Furthermore, the conveyance distance 122 on the transparent plate 24 to the standby position 24b of the subsequent document D2M can be ensured to be sufficiently larger than the conveyance distance 112 when the first dimension 111 is determined by the reduction control of the press roller 36a. can. As a result, the distance for conveying the subsequent document D2, which is waiting at the standby position 24b after the completion of the reading exposure of the preceding document DIM, to the reading position 24a becomes the interval W2, and the first
This is sufficiently shortened compared to the distance W1 when the dimension is 111.

Note that when conveying the subsequent document D2M to the reading position 24a, the press roller 36a is moved to the lower position to sufficiently transmit the conveyance force of the belt 35 to the document D2M, and after conveyance, the size of the document D2M is again adjusted. Accordingly, move upward 1.

Furthermore, FIG. 6(3) shows the press roller 36c and the contact piece 4.
7, the document DIS having the feeding direction dimension 131 (third dimension) that satisfies the relationship W3>131 (6) is the read value! 24a is shown. When it is determined that the dimension of the document D1 to be fed is the third dimension, the two press rollers 36a on the upstream side in the feeding direction
, 36b move to the upper position, and the pressing force on the belt 35 is controlled to be reduced. Therefore, the original DIS is conveyed under pressure to the reading position 24a by the press rollers 36c to 36e, and a gap is formed between the belt 35 and the transparent plate 24 on the upstream side in the feeding direction from the press roller 36c. Therefore, the subsequent document D2S is placed at the standby position 24 where its downstream end in the feeding direction reaches the press roller 36C.
It is possible to perform standby feeding up to b. That is, the interval 13 between the preceding original DIS and the waiting subsequent original D2S
3 is an interval obtained by subtracting the dimension 131 in the feeding direction from the interval W3, and is set according to the dimension 131.

Further, the conveyance distance f32 on the transparent plate 24 to the standby position 24b of the subsequent document D2S is determined by the press roller 36a,
By reducing the distance 36b, it is possible to ensure that the second dimension 121 is sufficiently larger than the distance 122. As a result, the distance required to convey the subsequent original D2S, which is waiting after the reading exposure of the preceding original DIS, to the reading position 24a is the interval W3, and the first dimension 1 described above is
11 and the second dimension 121. Note that the subsequent document D2S is read at the reading position 24.
When conveying to document D2S, the press roller 36a or press roller 36b is moved to a lower position to sufficiently transmit the conveyance force of the belt 35 to the document D2S, and after the conveyance, the document D2S is rotated to an upper position according to the dimensions of the document D2S. Move to.

Therefore, in the conventional configuration, the conveyance distance to the standby position is the same regardless of the size of the different types, but according to this embodiment, the arrangement along the feeding direction is Since the pressing force of the pushing slope is controlled to be reduced in order, the following original can be brought close to the preceding original without colliding with the preceding original and can be fed in advance in a standby manner. Accordingly, as the size is reduced, the distance required to transport subsequent originals waiting at standby position 1 to the reading position can be shortened, and as a result, multiple originals can be transported to reading position 1. The time it takes to do this can be significantly reduced.

Referring again to FIG. 1, an optical reading means 48 is provided inside the body with respect to the transparent plate 24.

As described above, the document conveyed to the reading position 24a is optically scanned by the optical reading means 48, and the presented document image is read and exposed.

After the reading exposure is completed, the transparent plate 24 is caused to protrude by excitation of a solenoid SQL (not shown). Contact piece 4
7 is angularly displaced as shown by the imaginary line in FIG. 1, and the reading position W 24 a opens the conveying path 49 that goes downstream in the feeding direction. As the belt 35 is released, the belt 35 is rotated clockwise again, and the document whose reading exposure has been completed at the reading position 24a starts to be discharged and transported to the transport path 49.

At the same time, the subsequent document D2 that has been waiting at the standby position 24b is conveyed along the feeding direction 26 to the reading position 24a. At this time, the press rollers 36a and 36b, which have been reduced and controlled according to the dimensions as described above, are moved to the lower position to sufficiently transmit the conveying force of the belt 35 to the document D2. When the subsequent document D2 is conveyed to the reading position 24a, the pressing force of the corresponding press rollers 36a and 36b on the belt 35 is controlled to be reduced again according to the dimensions of the conveyed document D2 as described above. , further forming a gap for a standby position for the subsequent document D3, and thereafter, the document D3
Executes standby feeding.

Further, the document conveyed to the conveyance path 49 is conveyed by conveyance rollers 50 and 51, and is discharged onto the document discharge table 52. In the vicinity of the abutment piece 47 with respect to the conveyance path 49, a discharge detector S5 including, for example, a light emitting element S5a and a light receiving element S5b is disposed. The discharge detector is at reading position 2.
4a is discharged to the conveyance path 49, and it is determined whether or not there is a paper jam in the path. When the downstream end of the conveyed document sheet in the feeding direction is detected, the The solenoid SQL is controlled to cause the contact piece 47 to protrude from above the transparent plate 24 again. This ensures that the document D2 following the discharged document D1 is placed at the reading position 2.
4a to prevent the document D2 from being discharged to the conveyance path 49.

Furthermore, in the vicinity of the document ejection table 52 with respect to the conveyance path 49, an ejection detector S6 including, for example, a light emitting element S6a and a light receiving element S6b is disposed.

The paper ejection detector S6 detects the state of one feed of the document through the conveyance path 49, and determines whether or not the document has been reliably ejected to the document ejection table 52.

In this way, the originals placed in a stack on the original placing table 25 are sequentially fed to the reading position 24a, read and exposed, and then discharged to the original delivery table 52.

Next, the internal configuration of the copying machine 22 will be briefly described with reference to FIG. The optical reading means 48 includes a first moving body 5 having a light source 53 such as a halogen lamp and a reflecting mirror 54.
5, a second moving body 58 having reflecting mirrors 56 and 57, a zoom lens 59, and further a reflecting mirror 60.

The light source 53 irradiates the original document presenting the original image to the reading position 24a, and the first moving body 55 moves in the direction of the arrow 6.
1, the document tray is optically scanned, and the document tray is read and exposed. During the reciprocation of the first moving body 55, the second moving body 58 moves in the same direction at half the traveling speed of the first moving body, thereby keeping the optical path length of the reflected light reflected from the document tray constant. to hold.

The reflected light from the original plate forms an image on a right cylindrical photoreceptor 63, which has a vertical axis in FIG. 2 and is rotated in the direction of arrow 62. The outer surface of the photoreceptor 63 is charged in advance by a charging corona discharger 64, and an electrostatic latent image corresponding to the original image read by the imaging is formed. The electrostatic latent image is visualized into a toner image by a developing device 65, and transferred onto one surface of the recording paper P by a transfer corona discharger 66. The recording paper P is stored in a paper feed cassette 67 in advance, and is transported by a transport means 69 including a pair of registration rollers 68 and guided to a transfer area 70 . A power transmission means is connected to the rotation shaft of the registration roller 68 via a clutch CLT (not shown). By performing the connection/disconnection control of the clutch CLT in relation to the conveyance state of the document tray, the photoreceptor 63
The timing of conveyance of the recording paper P by the registration rollers 68 can be matched with respect to the upper toner image. The recording paper P onto which the toner image has been transferred by the transfer corona discharger 66 is guided from the conveyance means 71 to the fixing device 72 and is fixed thereon.

In the case of single-sided copying, the recording paper P after fixing is immediately discharged through the conveyance path 77 to a tray 78 outside the machine.

On the other hand, in the case of double-sided copying, the recording paper P after the fixing is
The conveyance direction is reversed by the direction changing means 73, and the sheet is temporarily stored in the intermediate storage means 75 via the conveyance path 74. The recording paper P in the intermediate storage means 75 is led to the transfer area 70 again by the conveyance means 76 and the registration rollers 68, and the toner image is transferred to the other surface of the recording paper P. The recording paper P on which the transfer has been completed is discharged to a tray 78 outside the machine via a conveyance means 71, a fixing device 72, and a conveyance path 77. By thus cooperating the copying machine 22 and the document feeding device 21, single-sided copying and double-sided copying onto the recording paper P can be performed.

Further, the paper feed cassettes 67, 79 to 81 store recording papers P having mutually different dimensions, and are selected in accordance with the dimensions of the document sheet to be brought to the reading position 24a and placed in the transfer area 70. transported to.

FIG. 7 is a block diagram showing the electrical configuration of the document feeding device 21. As shown in FIG. A size detector S1 and a sheet length detector S3 that detect the dimensions of the original document to be transported along the feeding direction. Document detector S2 that detects the conveyance state of the document, discharge detector S
5, and a discharge detector S6. Furthermore, press roller 36a
, 36b from the roller position detector S4, a central processing circuit (hereinafter referred to as rcpuJ) 82 consisting of, for example, a microcomputer etc.
is input to. The CPU 82 determines the conveyance state of the document based on each of the detection signals and controls each circuit.

The CPL 182 includes a read-only memory (ROM).
83 and a random access memory (RAM) 84 are connected, and according to a control program stored in advance in the memory 83, the cpus 2 controls the copying operation by cooperating with the copying machine 22 and document feeding device 21. Memory 8
4 is used as a calculation area for counters, timers, flags, etc. necessary for controlling copying operations, for example. The CPU 82 includes, as the flag area, an area of a coincidence flag F used to determine the correspondence between the dimension of the original document to be conveyed along the feeding direction 26 and the press rollers 36a, 36b to be subjected to reduction control, as will be described later. A motor drive circuit 84, a solenoid drive circuit 85, and the like are connected to. Each of the drive circuits 85 and 86 drives the memory 83 and 84 based on signals from the various detectors 81 to S6.
controlled according to the program. Motor drive circuit 85
are connected to various motors such as a motor Ml that moves the press rollers 36a and 36'b up and down, a motor M2 that rotationally drives the rollers 33 and 34 and conveys the belt 35, and a motor M3 that drives various conveyance rollers. . Various solenoids such as a solenoid SQL that causes the contact piece 47 to protrude and retract from the surface of the transparent plate 24 are connected to the solenoid drive circuit 86 .

FIG. 8 is a flowchart for explaining the document feeding operation in this embodiment. In the program shown in FIG. 8, an original to be copied is placed on the original placing table 25,
Starts when the print switch is operated. Note that the document placed on the document placing table 25 may be a document having different sizes, such as A4 size and A3 size. It is determined whether or not the original document to be loaded has been placed. Manuscript Dii! After f, the size detector S1 is activated in step n2, and the size of the placed document is determined based on the combination with the regulating position of the alignment plate 27, for example. However, the dimensions determined at this point are based on the dimensions detected by the size detector S1, and, for example, not all of the mixed dimensions are determined. Therefore, for example, even if an A4 size original is stacked above an A3 size original, the size of the original determined at this point will be A3 size.

In step n3, the coincidence flag F is set to a reset state, and the press rollers 36a and 36b are set in a correctable state. In step n4, it is determined which of the first dimension to third dimension the document size determined in advance in step n2 is, and the corresponding press roller 36a, 36b is
is moved up and down to reduce the pressing force on the belt 35.

In step n5, the press roller 36a36b is moved to the corresponding position based on the detection result from the roller position detector S4.
, and step n4. until the movement is confirmed. Repeat step n5, after completing the movement, step n5
At step 6, it is assumed that the movement correction of the press rollers 36a36b has been completed, and the match flag F is set to the set state.

Thereafter, in step n7, paper feeding starts from the uppermost original in the stacking direction on the original placing table 25.

In step n8, the dimensions of the document to be fed are detected by the sheet length detector S3. As a result, even if the document has a different size that is not detected by the size detector S1, the size can be reliably determined when feeding the document to the reading position 24a, and as described later, the size of the document can be determined reliably.
, 36b on the belt 35 can be switched and corrected.

In step n9, the press roller 36a, which is set as described above based on the detection result by the sheet length detector S3,
It is determined whether or not the positions of the rollers 36b correspond to each other based on the detection signal from the roller position detector S4. When the dimensions and roller positions correspond, the process proceeds to step n1.
3, the original document fed to the reading position 24a is read and exposed by the optical reading means 48, and a copying operation is executed. On the other hand, if it is determined in step n9 that the detected dimensions and roller position 1 do not correspond, the process proceeds to step nlO, where the coincidence flag F is temporarily set to a reset state, and the press rollers 36a, 36b Correct and move the position again so that it corresponds to the dimensions of the document tray. Thereafter, in step n12, the coincidence flag F is set, and in step n13, a copying operation is performed on the document fed to the reading position 24a.

Note that the processing from step 08 to step n12 is as follows:
A roller position correction operation executed to achieve higher quality and higher speed, the steps n8 to n1
2 may be omitted, so in the case of said omission, said press roller 36a.

36b is controlled only according to the dimensions determined based on the size detector S1.

When the copying operation is completed, the process proceeds to step n14, and it is determined from the detection result of the document detector S2 whether or not document feeding has been completed. If the judgment is negative, the process returns to step n7, and the above process is repeated.
The press rollers 36a and 3
The position of 6b is corrected and the copying operation is performed. on the other hand,
If the judgment in step n14 is affirmative,
The process proceeds to other processes such as stopping the operations of the copying machine 22 and document feeding device 21.

Therefore, according to this embodiment, when feeding a plurality of sheet-like originals to a reading position, the belts of the plurality of press rollers on the upstream side in the feeding direction are It is possible to reduce and control the pressing force on the document with a simple configuration, thereby making it possible to bring the standby feeding position of the subsequent document sufficiently close to the preceding document. Therefore, the distance, or transport time, required to transport the document following the preceding document to the reading position is significantly shortened, and as a result, the time required to feed multiple sheets of document to the reading position is significantly reduced. can do. Therefore, the copying time in the copying machine can be significantly shortened.

Although this embodiment has been described in relation to the configuration of a transfer type electrostatic copying machine, it may also be configured to copy onto photosensitive recording paper, for example.

Further, the number of press rollers that control the reduction of the pressing force of the belt is not limited to two, but may be more than two, and depending on the number of press rollers to be controlled, The range of document dimensions for which the combination of controls is set is determined.

Effects of the Invention According to this book, the pressing force of the plurality of pressing rollers on the belt from the upstream side in the feeding direction is set in a combination corresponding to the reduction in the size of the document fed in advance. Mitigation is controlled by a simple configuration. Therefore, a gap is formed between the belt and the original reading surface, and the original that is fed subsequent to the preceding original can be kept sufficiently close to the preceding original and kept on standby. Therefore, the time required for ejecting the preceding original and transporting the following original onto the original reading surface can be significantly reduced. The time spent on can be significantly reduced. Therefore, the copying time in a copying machine equipped with the document feeding device can be significantly shortened.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a simplified configuration of a document feeding device 21 which is an embodiment of the present invention, and FIG.
3 is a side view showing a simplified configuration of the press roller 36c, and FIG. 4 is a sectional view showing a simplified configuration of the press roller 36a. A front view, FIG. 5 is a side view showing a simplified configuration of the press roller 36a, FIG. 6 is a diagram for explaining the setting operation of the press rollers 36a to 36e in this embodiment, and FIG. 7 is a diagram showing the document feeding. FIG. 8 is a block diagram showing the electrical configuration of the device 21, FIG. 8 is a flowchart for explaining the document feeding operation in this embodiment, and FIG. 9 is a sectional view showing the simplified configuration of the conventional document feeding device W1. , FIG. 10 is a diagram for explaining the conventional problems. 21... Original feeding device, 22... Copying machine, 24...
・Transparent plate, 24a...reading position! , 24b - Standby position, 26... Feeding direction, 35... Belt, 36a-36
e-press roller, 48... optical reading means, 63...
・Photoreceptor, Sl...Size detector, S3・Sheet length detector, S4...Roller position detector, M motor, D・
・・Manuscript agent Patent attorney Number of strokes Keiichi F.

Claims (1)

[Scope of Claims] A belt for feeding a sheet-like original onto the original reading surface of a copying machine; a plurality of pressing rollers that press upward, the plurality of pressing rollers being predetermined from the upstream side in the feeding direction when a previously fed document is placed on the document reading surface; A pressing force on the belt is controlled to be reduced individually in the order of arrangement according to a reduction in the dimension of the fed document along the feeding direction.