JPH1120959A - Sheet feeding device and image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide simply structured sheet feeding and image reading devices capable of preventing overlapped feeding of documents. SOLUTION: During sheet feeding, the gas injection of a gas injecting means 14 is controlled by a control means, a moving means 13 is also controlled, and then a housing member 12 is brought close to a vacuum suction paper feeding means 2 and an uppermost sheet 1a housed in the housing member 12 is sucked by the vacuum suction paper feeding means 2. Then, the housing member 12 is stopped based on a detecting signal from a suction detecting means 9 provided in the vacuum suction paper feeding means 2 for detecting the suction of the uppermost sheet 1a by the vacuum suction paper feeding means 2, then the housing member 12 is moved away from the vacuum suction paper feeding means 2 and, by gas injected from the gas injecting means 4 to the feeding direction end part of the uppermost sheet 1a, the sucked uppermost sheet 1a is separated from other sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus which is arranged in an image forming apparatus such as a copying machine or a facsimile and feeds a sheet to a main body of the image forming apparatus. About what you do.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a facsimile, a bundle of originals stacked for image formation is quickly fed to a platen to eliminate the risk of damaging the originals when reading an image. In order to minimize the stoppage of the apparatus due to jamming or double feeding of documents, malfunctions must be prevented. The greatest problem arises when separating a document bundle on which individual documents are stacked.

Heretofore, the separation of the original bundle has conventionally been performed by friction using a roller or a belt, for example. In the friction separation using such a separation roller or a belt, reliable separation and feeding are performed. The image surface of the original was rubbed and soiled, and the edge of the original became dirty due to friction separation by a belt, causing damage to the original.

Therefore, in order to surely separate the originals without causing any damage in the original feeding operation, for example, as shown in FIG. In this case, the upper document is fed separately by injecting air and feeding the document by gas injection means 14 for separating the uppermost document 1a.

In such a sheet feeding apparatus, the rear end regulating portion 10 of the upstream end of the original 1 in the transport direction is used.
Is provided with a height detecting lever 11, and the height detecting lever 11
The document storage tray 12, which is a storage member for stacking and storing the documents (sheets), is moved up and down based on the signal from the scanner so that the document surface is positioned at an appropriate height with respect to the vacuum suction feeding means 2. .

[0006]

However, in such a conventional sheet feeding apparatus, when the uppermost original 1a is fed by the weight of the height detection lever 11, the lower part of the upper original 1a is fed. The second side 1b is also fed, and double feeding may occur.

Further, the rear end regulating portion 10 of the storage tray portion 12 is provided.
By providing the height detecting lever 11, the operability of the document is not only deteriorated, but also the storage tray unit 12 is secured in order to secure the movement of the trailing end regulating unit 10 in the document conveying direction shown by the arrow in FIG. It must be cut, and the storage tray 12
However, there is a problem that the structure becomes complicated, and a height detection lever return mechanism has to be added.

Accordingly, the present invention has been made to solve such a conventional problem, and it is possible to prevent a double feed at the time of feeding a document and to provide a sheet feeding apparatus having a simple structure. It is an object to provide an image reading device.

[0009]

According to the present invention, there is provided a storage member for stacking and storing sheets, and disposed above the storage member.
Vacuum suction paper feeding means for vacuum-suctioning the vicinity of the downstream end of the uppermost sheet stored in the storage member in the paper feeding direction and feeding the uppermost sheet in the paper feeding direction; A gas ejecting unit that is arranged on the downstream side and that ejects gas toward the end of the top sheet in the sheet feeding direction so as to separate the top sheet and another sheet sucked by the vacuum suction sheet feeding unit; Moving means for moving the storage member up and down in the direction of the vacuum suction sheet feeding means; and suction means provided in the vacuum suction sheet feeding means for detecting that the vacuum suction sheet feeding means has sucked the uppermost sheet. Detecting means, and controlling the gas ejection of the gas ejection means at the time of sheet feeding, while bringing the storage member close to the vacuum suction sheet feeding means so as to adsorb the uppermost sheet to the vacuum suction sheet feeding means. When controlling the means of transportation Control means for stopping the storage member based on a detection signal from the suction detection means, and thereafter controlling the moving means to move the storage member in a direction away from the vacuum suction paper feeding means. It is characterized by the following.

Further, according to the present invention, when the detection signal is input for a predetermined time from the suction detection means,
The moving means is controlled so as to stop the moving means upon judging that the vacuum suction sheet feeding means has sucked the uppermost sheet.

Further, the present invention is characterized in that the suction detecting means is provided inside a vacuum suction part of the vacuum suction feeding means.

Further, the present invention is characterized in that the suction detecting means is a photo sensor.

Further, the present invention is characterized in that the suction detecting means is a pressure sensor for detecting a change in suction pressure of the vacuum suction feeding means.

According to another aspect of the present invention, there is provided an image reading apparatus having a sheet feeding device and reading means for reading an image of a sheet fed from the sheet feeding device. Characterized in that it is described in any one of (1) to (5).

Further, as in the present invention, when feeding the sheet, the control means controls the gas ejection of the gas ejection means and controls the moving means. The top sheet stored in the storage member is attracted to the paper means. Then, the storage member is stopped on the basis of a detection signal from suction detection means provided in the vacuum suction paper feeding means and detecting that the vacuum suction paper feeding means has suctioned the uppermost sheet. While being moved away from the paper means, the adsorbed top sheet is separated from other sheets by the gas ejected from the gas ejection means toward the end of the top sheet in the sheet feeding direction.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of an image reading apparatus provided with a sheet feeding device according to an embodiment of the present invention. In addition,
8, the same reference numerals as those in FIG. 8 indicate the same or corresponding parts.

In FIG. 1, reference numeral 1A denotes an image reading device, and 1B
Reference numeral 1 denotes a sheet feeding device, which is a sheet-like document (hereinafter, referred to as a document) 1 which is loaded on a storage tray 12 of the sheet feeding device 1B and records image information such as paper or synthetic resin.
Is transported by the vacuum suction paper feeding means 2 and the transport roller 30, and thereafter, the image reading apparatus main body (hereinafter referred to as the main body) 1
It passes through a fixed exposure unit 4 through a transport path 3 provided inside A1.

At this time, the image of the original 1 is read by the optical system of the fixed scanner 5, and the read original 1 is conveyed by the rollers 31 in the direction shown by the arrow, and is transferred to the original discharge tray 7. Is discharged.

The flow of the original indicated by an arrow in FIG. 1 indicates a case where image information recorded on one side of the original 1 is read. FIG. 2 shows a case in which image information recorded on both sides of the original 1 is read.
It shows the flow. Here, when reading the double-sided image of the original 1, as described above, the original 1 whose first surface has passed through the exposure unit 4 is inverted inside the main body 21a by the switching means 6 for switching between double-sided inversion and discharge. Then, the image information on the front and back surfaces of the original 1 is read by passing the second surface again through the exposure unit 4, and thereafter, the original 1 is discharged onto the original discharge tray 7.

Incidentally, as shown in FIG. 3, the vacuum suction feeding means 2 has a plurality of suction openings 21 for sucking the original 1.
a and a suction duct 21 having a suction means (not shown);
An endless belt 23, which is stretched over a pair of pulleys 22 provided on both sides of the suction duct 21 and has a number of holes (not shown) for adsorbing a document, and the pulley 22 is driven to rotate. Driving means 27 shown in FIG. 4 for driving the endless belt 23 is provided.

Further, the vacuum suction sheet feeding means 2 is provided near the suction opening 21a inside the suction duct, and includes suction detection means 9 for detecting suction of the document 1. In the present embodiment, a photo sensor is used as the suction detecting means 9.

On the other hand, a control device 25 as control means shown in FIG. 4 is provided at a predetermined position of the sheet feeding device 1B. Here, the control device 25 is provided in the document storage tray 12, and is provided in a document detection signal from a document detection unit 26 for detecting that the document 1 is set in the document storage tray 12 and an operation unit (not shown). An image reading start signal is input from the switch SW. The suction operation of the vacuum suction paper feeding means 2 is started based on these signals, and the storage tray 12 is moved to the vacuum suction paper feeding means 2. The motor 13 (see FIG. 3), which is a moving means for moving the storage tray 12 up and down so as to approach, is rotated forward, and the separation air injection operation by the separation nozzle 14 (see FIG. 3), which is a gas ejection means, is started. I have.

By raising the storage tray 12 and injecting the separation air in this way, when the uppermost document 1a reaches 8 mm or less from the vacuum suction feeding means 2, for example, the uppermost document 1a is separated by the separation air. The document 1a is separated and sucked by the vacuum suction feeding unit 2.

On the other hand, when the original 1a is attracted to the endless belt 23, a detection signal is inputted from the suction detecting means 9 which has detected the original 1a. 13 is stopped, and then the motor 13 is rotated in the reverse direction to lower the storage tray 12. When the storage tray 12 descends and the amount of the depression reaches a predetermined amount, the document 1 other than the uppermost document 1a being sucked is surely separated due to the separating effect by the separation nozzle 14.

As described above, by providing the suction detecting means 9 in the vacuum suction feeding means 2 and controlling the height of the storage tray 12 based on the detection signal from the suction detecting means 9,
With a simple structure, double feeding during document feeding can be prevented.

After the uppermost document 1a is sucked, the driving means 27 drives the endless belt 23 holding the document 1 to feed the document 1a.

By the way, after the uppermost original 1a is fed, the next original 1 is fed.
Is determined by the length of the document 1 in the transport direction. When the original 1 is placed on the original storage tray 12, the rear end regulating unit 10 is moved to match the rear end of the original 1 with the rear end regulating unit 10.
At this time, the control unit 23 makes a determination based on a signal output from the trailing end regulating unit 10 for identifying the length of the document 1 in the transport direction according to the movement amount.

On the other hand, in the present embodiment, the rear end of the previously fed original 1 is
The suction of the vacuum suction sheet feeding means 2 is started at the timing of exiting a.

Then, after the original is continuously fed at such a timing, the original 1 is exhausted from the original storage tray 12, and when the detection signal is not input from the original detecting means 26, the original feeding is terminated. I have to.

Next, the sheet feeding operation in the sheet feeding apparatus thus configured will be described with reference to the flowchart shown in FIG.

First, as shown in FIG.
When the document 1 is set on the document tray 2, a document detection signal is input from the document detection means 26 provided on the document storage tray 12 to the control device 25, and thereafter, when an image reading start signal is input from the switch SW, The control device 25 starts the suction operation of the vacuum suction sheet feeding means 2 (process 50), and
By rotating the motor 13 in the forward direction, the storage tray 12 is raised (lifted up) so that the storage tray 12 approaches the vacuum suction feeding means 2 (process 51). Further, the separation nozzle 1
4 is used to inject separation air. Note that, in the drawing, an arrow a indicates the adsorbed air, an arrow b indicates the separation air, and an arrow c indicates the moving direction of the storage tray 12, respectively.

When the document 1 is set on the document storage tray 12, the controller 26 identifies the length of the document 1 in the transport direction by adjusting the trailing edge regulating portion 10 to the rear end of the document 1.

Next, when the original 1 approaches the paper feeding position and the uppermost original 1a reaches 8 mm or less from the vacuum suction paper feeding means 2, the separation air jetted by the separation nozzle 14 causes the original 1 to be removed. The uppermost document 1a is separated and sucked by the vacuum suction feeding means 2. Then, when the document 1 is sucked in this way, the suction detecting means 9 detects this and inputs a detection signal to the control device 25.

Next, when this detection signal is inputted for a predetermined time (Y in decision 52), the control device 25 stops the motor 13, and thereafter rotates the motor 13 in the reverse direction to thereby store the storage tray 1
2 is lowered (lifted down). Then, when the descending amount of the storage tray 12 becomes a predetermined amount, that is, when the storage tray 12 is lowered (lifted down) by a predetermined amount (decision 53)
Y), this time, due to the separating effect by the separation nozzle 14,
The originals 1 other than the uppermost original 1a being sucked are reliably separated.

After the uppermost original 1a is attracted as described above, the driving means 27 drives the endless belt 23 which is adsorbing the original 1, so that the uppermost original 1a as shown in FIG. The sheet is conveyed (step 54).

When the fed document 1a hits the transport roller 30, the suction of the vacuum suction feeding means 2 is stopped (step 55), and the driving of the endless belt 23 is turned off.
Change to F. As a result, the original 1a can be transferred to the transport roller 30, and thereafter, the original 1a is
Transported by 0.

A predetermined time elapses after the feeding of the uppermost document 1a is started (Y in decision 56).
The rear end of the original 1a is connected to the suction opening 2 of the vacuum suction feeding means 2.
After passing through 1a, it is determined whether or not the document 1 remains in the document storage tray 12. Here, if the document detecting means 26 does not detect the absence of the document (N in decision 57), the suction of the vacuum suction feeding means 2 is started again, and the operation of bringing the storage tray 12 close to the vacuum suction feeding means 2 is restarted. I do.

Finally, when there is no document in the document storage tray 12 and no document is detected by the document detecting means 26 (Y in decision 57), the document feeding is terminated.

In the above description, the case where a photosensor is used as the document suction detecting means 9 has been described. However, the present invention is not limited to this. May be used.

[0041]

As described above, according to the present invention, it is possible to prevent double feeding during document feeding by controlling the height of the storage member by the suction detecting means provided in the vacuum suction feeding means. It is possible to provide a sheet feeding device and an image reading device that are simple and have a simple structure.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image reading apparatus including a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a case where image information recorded on both sides of a document is read by the image reading apparatus.

FIG. 3 is a diagram illustrating a configuration of the sheet feeding device.

FIG. 4 is a block diagram of a control device of the sheet feeding device.

FIG. 5 is a flowchart illustrating a sheet feeding operation of the sheet feeding apparatus.

FIG. 6 is a diagram showing a state in which the sheet feeding device starts a sheet feeding operation.

FIG. 7 is a diagram showing a state of the sheet feeding device when feeding a sheet.

FIG. 8 is a diagram illustrating a configuration of a conventional sheet feeding apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 document 1a top document 1A image reading device 1B sheet feeding device 12 storage tray 2 vacuum suction feeding means 21 suction duct 23 endless belt 9 suction detection means 13 motor 14 separation nozzle 25 control device

Claims (6)

[Claims] 1. A storage member for stacking and storing sheets, and a vacuum suction unit disposed above the storage member and suctioning the vicinity of the downstream end in the sheet feeding direction of the uppermost sheet stored in the storage member. Vacuum suction paper feeding means for feeding the sheet in the paper feeding direction, and a top sheet and another sheet which are arranged downstream of the storage member in the paper feeding direction and are sucked by the vacuum suction paper feeding means are separated from each other. Gas ejecting means for ejecting gas toward the end in the sheet feeding direction of the uppermost sheet, moving means for moving the storage member up and down in the direction of the vacuum suction sheet feeding means, and the vacuum suction sheet feeding means Suction suction means for detecting that the vacuum suction paper feeding means has suctioned the uppermost sheet; and controlling the gas blowing of the gas blowing means during sheet feeding, and the vacuum suction paper feeding means. Adsorb the top sheet The fit said housing member controls the moving means so as to approach the vacuum suction feeding means stops the receiving member based on a detection signal from the suction detecting means,
And a control means for controlling the moving means so as to move the storage member in a direction away from the vacuum suction paper feeding means. 2. The control means determines that the vacuum suction sheet feeding means has sucked the top sheet and stops the moving means when a detection signal from the suction detecting means is inputted for a predetermined time. 2. The sheet feeding apparatus according to claim 1, wherein the moving means is controlled to perform the operation. 3. The sheet feeding device according to claim 1, wherein the suction detecting unit is provided inside a vacuum suction unit of the vacuum suction sheet feeding unit. 4. A sheet feeding apparatus according to claim 1, wherein said suction detecting means is a photo sensor. 5. A sheet feeding apparatus according to claim 1, wherein said suction detecting means is a pressure sensor for detecting a change in suction pressure of said vacuum suction paper feeding means. 6. An image reading apparatus comprising: a sheet feeding device; and reading means for reading an image of a sheet fed from the sheet feeding device. An image reading apparatus according to any one of the above.