JP2938527B2 - Automatic document feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a facsimile, an image scanner, a copying machine, and the like, and automatically feeds a plurality of set originals one by one. Related to the device.

[Conventional technology]

For example, as an automatic document feeder (hereinafter, also referred to as "ADF") provided in a facsimile machine, a set document is pressed by a press plate, and the start switch is pressed after a document detection sensor detects the document. When
The set manuscript is sent by pre-feed roller,
In many cases, the sheet is separated into one sheet by a driving roller and a friction roller and fed sequentially.

Therefore, even if a plurality of originals are stacked and set at once, the images are usually fed one by one from the bottom side and the images are read.

The friction roller is rotatably supported on a shaft, but a relatively large frictional force (braking force) is applied to the shaft, and at least the outer peripheral surface is formed of a member having a high friction coefficient such as rubber. When one document is sandwiched between the drive roller and the drive roller, the document rotates with the transport of the document by the drive roller. However, when two documents are sandwiched, the document (paper) Since the frictional force is relatively small, the second original is pressed against the drive roller and stopped, so that only one original directly in contact with the drive roller is fed.

[Problems to be solved by the invention]

However, in such a conventional ADF, when an operator sets a plurality of originals, three or more originals 24 are put together between the driving roller 16 and the friction roller 17 as shown in FIG. It may be pushed in.

When document feeding is started from such a state, the separation operation by the friction rollers described above does not work reliably, so that there is a problem that double feeding occurs in which two or more documents are fed at the same time due to poor separation. Atsuta.

When a plurality of originals are set, the leading edge of the originals to be fed later (the lowermost side in the illustrated example) as shown in FIG. If the paper is inserted as far as it goes in the upper part (in the example, the upper side), the separation of the original document also occurs, which causes the double feeding.

When double feeding occurs, an image of the upper original that has been sent in an overlapped manner cannot be read, resulting in a page missing.

The present invention has been made in view of the above points, and when a plurality of originals are set on the ADF as described above, the originals are pushed directly between the drive roller and the friction roller, as shown in FIG. An object of the present invention is to prevent the occurrence of double feeding by preventing the sheet from being set in such a state.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a press plate for holding a set document, a pre-feed roller for feeding the document, and a document presence / absence detecting means (sensor) and a driving roller for the automatic document feeder as described above. A stopper that locks the leading edge of the document set between the document and the stopper, and holds the stopper at a position where the leading edge can be locked when setting the document, separates the prefeed roller from the document surface, and releases the holding when transporting the document. In addition, a means for bringing the pre-feed roller into contact with the original surface while providing a contact state by its own weight is provided.

Further, the drive roller is provided below the document insertion path, and the stopper is rotatably supported by a rotating branch provided above the document insertion path, and at least a portion for locking the leading end of the document is inserted. It is preferable that the document is held at a position crossing the document insertion path in a state of being inclined downward in the direction.

(Operation)

In the automatic document feeder according to the present invention, even if a plurality of originals are inserted one upon another at the time of setting the originals, the leading end of each original is locked by the stopper held between the original existence detecting means and the driving roller. There is no such thing as being pushed between the drive roller and the friction roller.

Also, at the time of document setting, the pre-feed roller that feeds the document between the drive roller and the friction roller is kept at a distance from the document surface, so that when the document is inserted, the document hit by the pre-feed roller does not reach the stop position. Also, there is no possibility that the set original is bent by the pre-feed roller so that the leading end of the original does not correctly contact the stopper.

When the original is fed, the stop state of the stopper is released and the pre-feed roller comes into contact with the original surface. Therefore, the original is moved by the pre-feed roller into the state of the drive roller 16 and the friction roller 17 in the state shown in FIG. Then, only the originals directly contacting the drive roller 16 are reliably fed one by one.

During the feeding, the stopper always comes into contact with the leading end of the original document by its own weight, so that the original document to be fed faster is slightly shifted in a stepped shape into the drive roller and the depth of the friction roller. , The occurrence of double feeding of originals can be prevented.

Further, if the stopper is held at a position crossing the document insertion path in a state where the stopper is inclined downward in the document insertion direction, the inserted document is locked by the stopper in a state as shown in FIG. As a result, the occurrence of double feed can be more reliably prevented.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic side view showing a mechanism of an automatic document feeder according to the present invention, and FIG. 2 is a schematic side view showing an internal mechanism of a facsimile apparatus provided with the automatic document feeder.

An automatic document feeder (hereinafter abbreviated as “ADF”) shown in FIG. 1 includes a presser plate 19 for holding a document 24 to be set and a document 24 on the front side along a document insertion path 14.
Is arranged opposite to the pre-feed roller 18 for feeding in the direction of arrow P, and the pre-feed roller is
A drive roller 16 (lower side) and a friction roller 17 (upper side) for separating and feeding the originals 24 fed by the feeder 18 one by one are arranged so as to be in rolling contact with each other.

Further, between the pre-feed roller 18 and the drive roller 16, the sensor 1 as the document presence detecting means and the stopper 20 for locking the leading end of the document 24 to be set are provided.

The stopper 20 is a rotation fulcrum provided above the document insertion path 14.
20a is rotatably supported, and at least a portion for locking the leading end of the original is abutted against a fixed positioning pin 15 at a position crossing the original insertion path 14 in a state of being inclined downward along the original inserting direction. Is held.

A pickup arm 23 having two substantially L-shaped arms 23a and 23b and a claw 23c for locking the stopper 20 is rotatably supported on a shaft 16a of the drive roller 16 within a predetermined range. The pre-feed roller 18 is supported at the tip of the arm 23a, and the other arm 23b is connected to the operating member 21a of the solenoid 21.

When the solenoid 21 is turned on / off, the operating member 21a moves in the direction of arrow E, and the pickup arm 23 rotates to move the pre-feed roller 18 up and down in the direction of arrow F.

In the state shown in the figure, the solenoid 21 is OFF, and at this time, the claw 23c locks the stopper 20 to hold the leading end of the document 24 at a position where it can be locked, and the pre-feed roller 18 is separated from the document surface. maintain.

When the solenoid 21 is turned on, the pick-up arm 23 is applied rightward to disengage the stopper 20, and the above-mentioned holding is released, and at the same time, the pre-feed roller 18 is raised in the direction of arrow F to contact the original surface. Let it.

As the sensor 1, a transmission-type or reflection-type photo sensor, a microswitch, or the like is used in the same manner as the sensor 2 serving as a document leading-edge / rear-end detection unit, which will be described later. Shall be.

In the facsimile apparatus shown in FIG. 2, following the ADF 3 and the sensor 2 described above, two pairs of transport rollers 5, 6 are further arranged at intervals in the document transport direction. A light source 4 that illuminates the lower surface, mirrors 7a and 7b that sequentially reflect light reflected from the original surface, a lens 8 that collects the reflected light to form an image, and receives the image forming light to perform photoelectric conversion. A CCD image sensor 9 is provided at a predetermined position.

Therefore, documents with images such as characters and graphics on the bottom
When the sheet is fed one by one by the ADF 3, the image is converted into an electric signal by the CCD image sensor 9 while being further conveyed while being held between the conveying rollers 5 and 6, respectively. Is input to a facsimile control unit (FCU) to be described later, and then the original is sent out in the direction of arrow A.

At the rear of the facsimile apparatus, a thermal recording paper 10 wound in a roll is loaded, pulled out through a pressure contact portion between a thermal head 11 and a platen roller 12, and sent out in the direction of arrow B after printing. I do.

In the transmission mode, the FCU 13 modulates the image signal read by the CCD image sensor 9 and transmits the modulated image signal to the facsimile apparatus of the other party through the public line. In the copy mode, the FCU 13 transmits the image signal to its own thermal head 11 for thermal recording. A print is made on paper 10, and in a reception mode, a signal received from the outside is demodulated by facsimile communication, and the image signal is sent to thermal head 11 to be printed on thermal recording paper 10.

As shown in FIG. 3, the FCU 13 is supplied with power from a power supply unit (PSU) 25, and performs various detections from the sensor 1 for detecting the presence or absence of the document and the sensors 2 for detecting the leading and trailing edges of the document. A signal is input to drive and control the solenoid 21 and the original conveying motor 26.

The document transport motor 26 is connected to a
The drive roller 16, pre-feed roller 18, and all of the transport roller pairs 5, 6 shown in FIGS. 1 and 2 are rotationally driven.

Next, the operation of the facsimile apparatus will be described with reference to the flowchart of FIG.

In the standby state, the solenoid 21 is turned off and the ADF 3 is in the state shown in FIG. 1, and the original conveying motor 26 is stopped, so that the driving roller 16, the pre-feed roller 18, and the conveying roller pairs 5, 6 are all stopped. ing.

When a plurality of originals 24 are set by the operator in the standby state, the leading ends of the originals 24 abut against the stopper 20 and are locked, and as shown in FIG. It is set slightly out of step into the back. At this time, the pre-feed roller 18 is held in a state of being separated from the document surface.

As a result of the insertion of the original, the detection signal of the sensor 1 becomes a state in which the original is present (OFF because the transmission type photo sensor is used).
The FCU 13 determines this and shifts to a start standby state.

Then, when the start button (copy button in the copy mode) is pressed and turned on by the operator, the document feed motor 26 is driven to rotate the drive roller 16, the pre-feed roller 18, and the feed roller pair 5, 6. Let it.

Further, the solenoid 21 is turned ON, the pick-up arm 23 is applied to the right, the pre-feed roller 18 is raised to a position in contact with the lower surface of the original, and the stopper 23
Release the hold status of 0.

Then, all the set originals 24 are converted to the pre-feed roller 18
The document is then fed in the direction indicated by the arrow P in FIG. 1, and the lowermost document is sandwiched between the driving roller 16 and the friction roller 17 and further fed as shown in FIG.

At this time, the stopper 20 is pushed up by the document, but the leading end of the stopper rubs against the leading end of the document, thereby increasing the effect of shifting the document as shown in FIG.

In this embodiment, it is almost unlikely that two originals are simultaneously clamped between the drive roller 16 and the friction roller 17.
Due to the operation of 17, only one sheet of document directly contacting the drive roller 16 is fed.

When the leading edge of the fed document enters between the sensors 2,
The sensor 2 detects this, and the output signal changes from ON to OFF. In the detection of the leading edge of the document, the FCU 13 turns off the solenoid 21 and lowers the pre-feed roller 18 to stop sending the document by delaying the time until the leading edge of the document is clamped by the pair of transport rollers 5.

The fed document is transported in the direction of arrow A by the transport roller pairs 5 and 6 and its image is read. When the trailing end of the document passes the sensor 2, the sensor 2 detects that and turns off the output signal. Becomes ON from.

At this time, the sensor 1 is checked, and if the original 24 has been detected (if it has been turned OFF), there is still the original 24 set, so the process returns to the step of turning on the solenoid 21 again, and the subsequent processing is performed. repeat.

If the document is no longer detected (turned on) by the sensor 1 check, the ADF3 has fed the final document.
Is no longer lifted and held by the document, and is lowered and rests on the claw 23c of the pick-up arm 23.

Therefore, the solenoid 21 is turned on for a short time and then turned off immediately, so that the stopper 20 is lowered until it comes into contact with the pin 15 and is held at that position by the claw 23c of the pickup arm 23.

After that, the document feed motor 26 is stopped by delaying the time until the final document leaves the feed roller pair 6, and the rotation of the drive roller 16, the pre-feed roller 18, and the feed roller pairs 5 and 6 is all stopped, and the standby state is established. become.

Although the embodiment in which the present invention is applied to a facsimile apparatus has been described above, the automatic document feeder according to the present invention can be similarly applied to an image scanner and a copying machine.

〔The invention's effect〕

As described above, in the automatic document feeder according to the present invention, the drive roller for separating and feeding documents one by one and the stopper provided on the front side of the nip portion of the friction roller are provided at the leading end of the document to be set. And the pre-feed roller that feeds the set document during conveyance of the document between the drive roller and the friction roller comes into contact with the document. 8, it is no longer set in the state shown in FIG.
The document surface is not bent by the feed roller during document setting, and the stopper is kept in contact with the leading edge of the document while the document is being fed, so that the leading edge of the document always contacts the drive roller and the friction roller. As a result, it is possible to prevent double feeding due to poor separation of originals.

Further, if the leading edge of the document is locked in a downwardly inclined state along the stopper document insertion direction, the document can be set in a more easily separable state, and the effect of preventing double feeding can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a mechanism of an automatic document feeder according to an embodiment of the present invention, FIG. 2 is a schematic side view showing an internal mechanism of a facsimile apparatus having the automatic document feeder, FIG. 4 is a block diagram of a portion related to the FCU of the facsimile apparatus shown in FIG. 2, FIG. 4 is a flow chart showing the operation of the facsimile apparatus shown in FIG. 2 according to the present invention, and FIGS. FIGS. 7 and 8 are explanatory views corresponding to FIGS. 5 and 6 for explaining the problems in the conventional automatic document feeder. DESCRIPTION OF SYMBOLS 1: Document presence / absence detection sensor 2: Document top / bottom edge detection sensor 3: Automatic document feeder (ADF) 4: Light source, 5, 6: transport roller pair 9: CCD image sensor 10 … Thermal recording paper, 11… Thermal head 12… Platen roller 13… Facsimile control unit 14… Document insertion path, 16… Drive roller 17… Friction roller 18… Pre-feed roller 19… Pre-shear Plate 20: Stopper, 21: Solenoid 23: Push-up arm, 24: Original

Claims (2)

(57) [Claims] 1. A push plate for holding a set original, a pre-feed roller for feeding the original, a driving roller and a friction roller for separating and feeding the originals fed by the free feed roller one by one,
An automatic document feeder comprising: a document presence detecting unit provided between the pre-feed roller and a driving roller; and a stopper for locking a leading end of the set document between the document presence detecting unit and the driving roller. The stopper is held at a position where the leading end thereof can be locked when the original is set, the pre-feed roller is separated from the original surface, the holding is released when the original is conveyed, and the contact is made by its own weight. Means for contacting a pre-feed roller with the document surface. 2. The automatic document feeder according to claim 1, wherein a driving roller is provided below the document insertion path, and said stopper is pivotally mounted on a rotation fulcrum provided above the document insertion path. An automatic document feeder which is supported and held at a position crossing the document insertion path in a state where at least a portion for locking the leading end of the document is inclined downward along the document insertion direction.