JPH0729738B2 - Automatic document feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder that feeds and conveys a sheet document to an exposure section of a copying machine having a double-sided copy function, and more particularly, it automatically prints both sides of a document. The present invention relates to an automatic document feeder having a function of automatically reversing documents in page order for copying.

2. Description of the Related Art In recent years, when the acceptance of copying machines has increased, the amount of work has increased and the work needs to be simplified as the amount of copies of sheet originals on the front side other than sheet originals on one side has increased. Among them, a copying apparatus that automatically copies a double-sided sheet original on both sides of a sheet to be copied makes the copying work more efficient. However, after the sheet original is placed on the platen for exposing, that is, after the front side copying of the original is completed. The work of turning over the original and copying the back side was done manually by hand.

Problems to be Solved by the Invention However, as described above, the work of manually placing an original on the exposure platen by hand is a work of replacing the original while checking the page order, the top and bottom of the original, and the like. There is a problem in that the work of opening and closing the cover is required, which is a troublesome work. There is also an automatic document feeder that automatically reverses the original so that the front and back of the original can be copied. For example, to reverse an A3 original, which is the maximum size of commonly used originals, ,
Since a reversing unit corresponding to the longitudinal dimension of A3 size is required, it becomes a large-sized device, which cannot be installed in a normal office, and it has a serious drawback that it is expensive and difficult to spread.

The present invention solves such conventional problems,
The sheet originals placed in page order on the paper feed tray are automatically fed and conveyed to the exposure platen, and after exposure, the sheet originals are automatically inverted and conveyed to the exposure platen again, and the post-exposure discharge tray It is an object of the present invention to provide an automatic double-sided document feeder for transporting a sheet to an automatic double-sided document feeder, and further to eliminate the drawback of the conventional automatic double-sided document feeder, which is large and expensive. That is, since the conventional automatic double-sided document feeder is extremely large and expensive, it has been adopted only in a special large-sized copying machine, which is installed and purchased in a centralized copying room or a copying company. The present invention provides an automatic double-sided document feeder used in a popular copying machine used in an office.

Means for Solving the Problems In order to solve the above problems, an automatic document feeder according to the present invention is provided with a sheet feeding part for feeding a sheet document, a sheet document fed or a sheet reversed at a document passage part. The original is conveyed to the exposure platen or the sheet original on the exposure platen is conveyed to the original passage part.The conveyance part, the sheet original conveyed from the conveyance part is switched to the discharge part and sent. If the guide plate cannot be switched, the original document path that is turned over and sent again to the transport section is looped, and the size is small enough that the perimeter of the loop is sufficiently shorter than the sheet original that is relatively long in the running direction. The original document passage portion and the guide plate are composed of a sheet discharge portion for storing the sheet original document discharged from the original document passage portion on the sheet discharge tray.

Effect of the Invention With the above-described configuration, the present invention automatically feeds, conveys, and reverses a double-sided sheet original in page order when copying a double-sided sheet original in page order, in addition to copying the single-sided sheet original in page order. It is possible to reverse and eject the sheet, and the duplication work of the double-sided sheet original can be efficiently performed by an extremely small and inexpensive device.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional configuration diagram of an automatic document feeder according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a sheet document feed path in the automatic document feeder. FIG. 3 is a view showing a drive mechanism of a feed roller in a loop-shaped document passage, and FIG. 4 is a view showing a belt connection state of each feed roller in FIG. In FIGS. 1 and 2, reference numeral 1 denotes a sheet original, which is placed on the paper feed tray 2. 3 is a sheet feeding roller, 4 is a platen for exposing a document, 5 is a conveyor belt for conveying a fed sheet original to a fixed position on the platen, 6 is a belt driving roller for driving the conveyor belt 5, and 7 is a loop , A paper feed roller that feeds a sheet original in the original passage, 8 a paper guide forming a loop-shaped original passage, 9 a discharge roller, and 10 a original passage for sending a sheet original to a discharge portion or a platen. A guide plate for switching, 11 is a discharge tray for holding discharged sheet originals, and 24 is a fulcrum of the guide plate 10.

In FIGS. 3 and 4, 12, 13, 14 are feed belts for connecting and driving the feed rollers, 15, 21 are drive shaft gears for transmitting the driving force from the belt drive rollers, 16, 17, 18, 19, 20. Is a feed roller pulley connected to the feed roller, 22 is a drive shaft of the belt drive roller, and 23 is a one-way clutch for rotating the feed roller pulley in only one direction.

The operation of the automatic document feeder configured as described above will be described below with reference to FIGS. 1 to 4.

First, when the sheet feeding roller 3 is rotationally driven, the sheet original 1 is fed, and further conveyed by the conveying belt 5 on the platen 4 and fed into the loop-shaped original passage formed by the paper guide 8. At this time, in response to a signal for copying the back side of the sheet original, the guide plate 10 moves around the fulcrum 24 to close the passage to the paper discharge portion and form a passage to the platen 4 side.

In this state, the sheet original 1 is conveyed to a predetermined position on the platen 4 by the feed roller 7. After the copying exposure is completed, the sheet original 1 is again sent to the loop-shaped original passage on the side opposite to the paper feeding by the conveyor belt 5. At this time, similarly to the above, in response to a signal for copying the surface of the sheet original 1, the guide plate 10 makes a path to the platen 4 side, and the sheet original 1 again passes through the loop-shaped original path to a predetermined position on the platen 4. The copy surface is sent in the opposite direction. Here, the size of the loop is extremely small, that is, the loop-shaped document path is extremely small, that is, the path length of the loop-shaped document path is set to be at least shorter than the length of the longest document in the usable path direction. When the sheet original 1 is sent from the platen 4 to the platen 4 again via the loop-shaped original passage, the trailing edge of the sheet original 1 is still between the platen 4 and the conveyor belt 5 which is in contact with the upper surface thereof. Sometimes, the leading edge of the document is caught between the transport belt 5 and the trailing edge of the document, and at this time, the transport belt 5 is reversed. At this time, the trailing edge and the leading edge of the same sheet original 1 exist between the upper surface of the platen 4 and the lower surface of the conveying belt 5, and they are conveyed in opposite directions. The frictional force of the sheet original 1 is large. This is because the conveyor belt 5 is made of a material having a large friction coefficient so that the sheet original 1 can be conveyed. Therefore, due to the frictional force between the front and rear ends of the sheet original 1, that is, between the sheet originals and the frictional force between the rear end of the sheet original 1 and the upper surface of the platen 4, the friction between the front end of the sheet original 1 and the conveyor belt 5 is caused. The power is much greater. Further, rather than the force of the reversely conveyed conveyor belt 5 conveying the rear end of the sheet original 1 in the opposite direction,
Since the conveyance force for feeding the sheet original 1 in the forward direction by the feed roller 7 in the loop-shaped original passage is sufficiently large, the leading edge of the sheet original 1 is moved forward while the leading edge and the trailing edge of the sheet original 1 slide on each other. , That is, the sheet original 1 is sent onto the platen 4 and stays at a fixed position. Generally, the maximum document size is the JIS standard A3 size, which is often used to feed sheet documents in the longitudinal direction.However, in this type of conventional device, the perimeter of this loop-shaped document path is the A3 size length. Greater than the lateral dimension of 420 mm, so the average diameter is 133 mm
However, in the present invention, since it is only necessary to consider the bending of the sheet document regardless of the document size, it is possible to set the average diameter to about 30 mm,
It has been realized.

In addition, the page order of the sheet original 1 placed on the paper feed tray 2,
The present invention provides an excellent automatic document feeder, of course, that the page order of the sheet originals 1 ejected to the paper ejection tray 11 and the page order of the copied copy sheets are exactly the same. .

After the exposure, the belt driving roller 6 again rotates in the forward direction to drive the conveying belt 5 to feed the sheet original 1 to the side opposite to the paper feeding portion, and at the same time, the next sheet original 1 is placed on the platen 4 in the same manner as described above. Send in. The copy-completed sheet original 1 is sent to the loop-shaped original passage by the feed roller 7, and at this time, the guide plate 10 opens the passage to the paper discharge portion, contrary to the above, and the sheet original 1 is discharged to the discharge tray 11. The paper is discharged by the paper discharge roller 9.

FIGS. 3 and 4 show how the driving force of the belt driving roller 6 is transmitted to the feeding roller 7 and the paper discharging roller 9, and the belt driving roller 6 rotates forward, that is, the driving shaft 22 moves forward. When rotated, the drive shaft gear 21 does not rotate by the one-way clutch 23, but the feed roller pulley 16 rotates. As a result, the forward rotation driving force of the drive shaft 22 is transmitted to the feed roller pulley 17 via the feed belt 13 and further to the feed roller pulleys 19 and 20 via the feed belt 12. When the drive shaft 22 rotates in the reverse direction, the feed roller pulley 16 is a one-way clutch.
Although it does not rotate due to 23, the drive shaft gear 21 rotates together with the drive shaft 22, and this drive force is applied to the drive gear 15 and the feed roller pulley 18
And to the feed roller pulley 17 via the feed belt 14 and further to the feed roller pulleys 19 and 20 via the feed belt 12. Also in this case, the feed roller pulleys 17, 19 and 20 rotate forward. That is, the feed roller 7 and the paper discharge roller 9 always rotate normally regardless of whether the belt drive roller 6 rotates normally or reversely.

As described above, according to the present embodiment, the path length of the loop-shaped document passage can be extremely reduced as a device for copying a double-sided sheet document. In other words, in the conventional device, the average diameter of 133 mm is too high, so in reality it is a horizontally long ellipse, but for example, if the short diameter is 30 mm, the long diameter will be about 200 mm, so it is automatic. A unit separate from the document feeder main unit has been devised, but in any case, it is not used in a general office because it is large and expensive, and has only a special purpose. However, in this embodiment, since the loop portion has a diameter of 30 mm, it can be realized in a very small size, and therefore it can be provided in the same frame without increasing the outer size as a part of the main body of the automatic document feeder. Also, when copying a double-sided sheet document, it is possible to automatically perform double-sided copying without manually turning the sheet document upside down.

As described above, according to the present invention, after copying one side of a double-sided sheet original, the sheet original is passed through a loop-shaped original passage and the inverted sheet original is set at a fixed position on the platen by switching the guide plate.
The present invention realizes an automatic document feeder capable of automatically performing double-sided copying.

Further, although the conveyor belt rotates in both forward and reverse directions by one motor, the feed roller in the loop-shaped document passage is not always rotated in the normal direction, and the sheet document reverse rotation passage and the sheet discharge passage are shared. When the sheet original is reversed, the leading edge of the original is conveyed onto the platen while the trailing edge of the original is still on the platen, so the conveyance path of the sheet original can be extremely shortened. It was possible to realize a double-sided automatic document feeder of almost the same size as the automatic document feeder. The conventional double-sided automatic document feeder is about 200 mm larger than one side for A3 size documents, so it is either a separate unit or a very large size. It was limited. It should be noted that the manuscript is not A3 size, and the leisure size, which is often used in North America, has become larger because the longitudinal direction becomes larger. As described above, according to the present invention, since it can be provided in a space and price that can be installed in a normal office, it has been rapidly spread as an automatic document feeder capable of copying double-sided documents, including general offices, and sheet documents It is possible to efficiently carry out the copying work.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of an automatic document feeder according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram schematically showing a sheet document feeding path, and FIGS. 3 and 4 are sheet document inversions. Or, it is a structural view showing a connection / driving mechanism of a belt driving roller and a feeding roller and a discharging roller in a loop-shaped document passage for discharging a sheet. 1 ... Sheet original, 2 ... Paper feed tray, 3 ... Paper feed roller, 4 ... Platen, 5 ... Convey belt, 6 ... Belt drive roller, 7 ... Feed roller, 8 ... Paper guide, 9 ...
… Paper ejection rollers, 10… Guide plate, 11 …… Paper ejection tray, 12,
13,14 …… Feed belt, 15,21 …… Drive shaft gear, 16,1
7, 18, 19, 20 …… Feed roller pulley, 22 …… Drive shaft, 2
3 …… One-way clutch, 24 …… Support point.

Claims (4)

[Claims] 1. A paper feeding means for feeding the originals one by one from a paper feed tray capable of accommodating a plurality of originals, a conveying means for conveying the originals, and the originals conveyed by the conveying means for re-copying the originals. A loop-shaped document path means for reversing the sheet to the transport means or discharging the sheet onto a sheet discharge tray, and a sheet discharge means for discharging a document whose front and back surfaces are exposed from the document passage means to a sheet discharge tray. The conveying means conveys the original sent from the paper feeding means or the original passage means to a predetermined position on the platen, and conveys the original exposed at this position to the original passage means. At the same time, the original fed from the paper feeding means is passed through the platen and conveyed to the original passage means, and the original passage means is a longest original in the passage direction at least the passage length of the original passage means. Less than the length of At the same time, a feed roller is provided in the document passage means, and the document conveying force by the feed roller is made larger than the frictional force between the document conveying means and the document so that the inverted document leading edge is the conveying means and the document trailing edge. An automatic document feeder, characterized in that it is conveyed in between. 2. An automatic document feeder according to claim 1, wherein at least the conveying means and the document passage means are provided in the same frame. 3. An automatic document feeder according to claim 1, wherein at least the paper discharge means and the document passage means are provided in the same frame. 4. An automatic document feeder according to claim 1, wherein the conveying means, the document passage means, and the paper discharge means are provided in the same frame.