JP2816996B2 - Automatic document feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic document feeder in a facsimile machine, a copying machine, an image scanner, or the like.

(Prior Art) When a plurality of documents are set on a document table in an overlapping manner, an automatic document feeder that separates and supplies documents one by one by cooperation of a feed roller and a separation roller pressed against the feed roller Generally well known.

However, one of the major problems in this type of automatic document feeder is that the user varies the separation performance depending on the state of the document set, and a specific example thereof is shown in FIG. 9 (a). Like the original D
The feed roller 31 and the separation roller
For example, when the original D is inserted into the gap between the originals 32 or as shown in FIG. 9 (b), a plurality of originals D are set in a wedge shape so that the upper original comes out earlier. In any case, it is known that so-called double feed, in which two or more originals are simultaneously sent, is likely to occur.

Therefore, some proposals have been made to solve such a problem. One of the proposals is, for example, that Japanese Patent Application Laid-Open No. 63-123740 discloses that when a document is set, the position of the leading edge of the document is fixed. Japanese Patent Application Laid-Open No. H11-157556 discloses a device provided with a stopper that abuts the leading edge of a document so as to be aligned. With this configuration, the leading end of the document is not inserted between the feed roller 31 and the separation roller 32, and the leading ends are aligned, so that double feeding can be prevented.

(Problems to be Solved by the Invention) However, in the above-described conventional technology, in order to avoid the stopper from the document path in response to the paper passing operation, control means on a system (on software) and driving means such as a solenoid are used. Must be prepared separately.

Most automatic document feeders have a mechanism that opens and closes the separation roller side with respect to the feed roller side to remove paper jams, or even if it is fixed, in relation to the document passing surface, The shutter driving means is mounted on the separation roller side, and thus, if an electric component is provided on the separation roller side, there is a problem that an undesired trouble easily occurs due to electrostatic or radio wave measures.

The present invention solves the above-mentioned problems of the prior art,
The shutter driving means is constituted by a mechanical mechanism, is inexpensive,
Another object of the present invention is to provide an automatic document feeder that is advantageous in terms of measures against static electricity and radio waves.

(Means for Solving the Problems) In order to achieve this object, an automatic document feeder according to the present invention includes a feed roller fixed to a feed shaft, a feed roller rotatable about the feed shaft, and a feed shaft. A pickup bracket having a pickup torque limiter between the pickup bracket and the pickup bracket, which is connected to the feed roller via a feed roller and an idle gear, rotates with the rotation of the feed shaft and the feed roller, and rotates the pickup bracket to rotate the lower surface of the document. And a separation roller which is rotatably provided at the other end of the separation roller bracket which is rotatable about its fulcrum O whose one end is supported, and which is urged to press against the feed roller by a spring. A document pressure plate having a lower surface pressing the upper surface of the document pressed against the pickup roller; A shutter that is rotatable about O and has a stopper portion that is positioned immediately before the separation roller and sets the leading edge of the document when setting the document, and a shutter that is rotatable about the feed shaft and between the feed shaft A shutter lever that has a limiter, rotates at a predetermined angle in accordance with the rotation of the feed shaft, and rotates the shutter so that the stopper portion rises and the document passes therethrough.

(Operation) According to this configuration, when the original is set, the stopper of the shutter is located immediately before the separation roller, so that the leading end of the original abuts the stopper and is set at a fixed position. Next, as the feed shaft starts rotating, the pickup roller is lifted up and pressed against the lower surface of the document, and at the same time as the document is started to be fed, the stopper portion of the shutter is raised to avoid the document path and pass the document. Since the sent original reaches the feed roller and the separation roller first, the leading end of the lowermost original is
The sheets are separated normally and sent. When the rotation of the feed shaft stops, the stopper automatically lowers. All of these operations are performed by a mechanical mechanism.

(Example) Hereinafter, an Example is described in detail with reference to drawings. First
FIG. 1 shows an automatic document feeder according to an embodiment of the present invention. FIG. 2 is a schematic view A in FIG. 1 and FIG. 3 is a schematic view B in FIG. FIG. 4 is a sectional view taken along the line CC of FIG. 3.

1 to 4, reference numeral 13 denotes a feed shaft, which has an electromagnetic clutch 21 at one end, and is connected or disconnected from a drive gear 27 rotated by a drive source (not shown) as needed. 12
Is a feed roller fixed to the feed shaft, 11 is a pickup bracket that is rotatable about the feed shaft 13 and has a pickup torque limiter 14 between itself and the feed shaft, 19 is attached to the pickup bracket 11,
The pickup roller 6 is connected to the feed roller 12 via the idle gear 20, rotates with the rotation of the feed shaft 13 and the feed roller 12, and presses against the lower surface of the document by the rotation of the pickup bracket 1. A separation roller bracket 8 that is rotatable about O is rotatably supported on the separation roller shaft 9 at the other end of the separation roller bracket 6, and is urged by a spring 5 so as to press against the feed roller 12. The separation roller 2 is a document pressure plate that presses the upper surface of the document whose lower surface is pressed against the pickup roller 19.
It is always urged by the pressure spring 3. Reference numeral 1 denotes a shutter which is rotatable about a fulcrum O and which has a stopper 1a which is located immediately before the separation roller 8 when the document is set and abuts against the leading edge of the document. Reference numeral 17 denotes a shutter which can rotate about the feed shaft 13; A shutter that has a shutter torque limiter 16 between itself and the feed shaft 13, rotates by a predetermined angle with the rotation of the feed shaft, and rotates the shutter so as to push up a part of the shutter 1 and raise the stopper 1 a. It is a lever. In addition,
4 is an upper base member, 18 is a lower base member, 7 is an upper guide plate, 10 is a lower guide plate, 15 is a bearing, 22 is a document presence / absence detection sensor, and 24 is a document table.

Next, the operation of this embodiment will be described. First, when a document is set, the stopper 1a of the shutter 1 is lowered, and therefore, a plurality of inserted documents are set with their leading ends abutting the stopper 1a. The document presence / absence detection sensor 22 detects the presence of a document and enters a paper passing standby state. When a paper feed ON switch (not shown) is pressed, it is connected to the electromagnetic clutch 21 and the driving force is transmitted to the feed shaft 13,
The feed roller 12 starts rotating. At the same time, the pickup bracket 11 is rotated by the action of the pickup torque limiter 14, and the pickup roller 19 is lifted up and pressed against the lower surface of the document. On the other hand, the shutter lever 17 also rotates by a predetermined angle by the action of the shutter torque limiter 16, so that the shutter 1 rotates and the stopper 1a rises to avoid the document path. Since the rotation of the feed roller 12 is transmitted by the idle gear 20 and the pickup roller 19 rotates, the original is fed to the feed roller 12 and the separation roller 8 pressed against the feed roller 12. Here, a separating operation is performed by a predetermined pressure and torque, and only the lowermost document is separated and supplied.

When a document passes a document feeder passage detection sensor (not shown), the electromagnetic clutch 21 is turned off, and the pickup roller 19 returns to the standby position. At the same time, the shutter stopper
1a is lowered and the document is placed on the next and subsequent pages. However, since the contact area and the contact pressure are not so large, the load does not increase so much and the normal separation and feeding operation is continued.

In the present embodiment configured as described above, the leading edge of the original is stopped by the stopper portion when the original is set, and the original is inserted between the feed roller and the separation roller as in the related art, or the upper original is moved to the top. Therefore, the separation and feeding are performed one by one without variation in the separation performance depending on the document setting state of the user.

FIGS. 5 and 6 show another embodiment of the present invention. The different part from the embodiment of FIGS. 2 and 3 is that an elastic member is provided immediately before the stopper 1a of the shutter 1. FIG. The point is that a document leading edge guide 23 is provided. With the guide 23, even if the document is curled, the leading end of the document can be smoothly guided between the feed roller and the separation roller. As the material of the guide 23, a leaf spring such as stainless steel or phosphor bronze, or a film such as polyester can be used.

FIGS. 7 and 8 show still another embodiment of the present invention. In this embodiment, the rear end of the original which can be adjusted on the original table 24 in accordance with the length of the set original is shown. Guide 25 is further provided. When the document is set, the front and rear of the document is securely held by the stopper 1a of the shutter 1 and the rear end guide 25 so that the front end of the document abuts on the stopper 1a, and the setting state is further uniformed.

(Effects of the Invention) As described above, according to the present invention, the set state of the original is always standardized such that the leading end of the set original abuts against the stopper portion of the shutter, and the pickup roller is fixed. With the rotation of, the lower document enters the feed roller / separation roller first.
Feeding is assured. Moreover, a series of operations of the shutter
The structure is performed mechanically in conjunction with the rotation and stop operations of the feed shaft, leading to cost reduction. In addition, since electric components such as solenoids are not used, it is advantageous in terms of measures against static electricity or radio waves. .

Further, in the case where a document leading end guide made of an elastic member is provided immediately before the stopper portion, in addition to the above effects,
Even if the document has a curl, it is possible to eliminate the influence on the separation performance.

Further, by providing the document trailing edge guide, the set state is further uniformed, and effects such as further improving the separation performance are exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view of an automatic document feeder according to an embodiment of the present invention, FIG. 2 is a schematic A view of FIG. 1, and FIG.
FIG. 4 is a schematic sectional view taken along the line CC of FIG. 3,
5 and 6 are configuration diagrams of another embodiment of the present invention, FIG. 7 is a configuration diagram of still another embodiment of the present invention, FIG. FIG. 9 shows a problem in the conventional example. 1... Shutter, 1a... Stopper portion, 2.
5 ... Spring, 6 ... Separable roller bracket, 8 ...
Separating roller, 11 ... Pickup bracket, 12 ... Feed roller, 13 ... Feed shaft, 14 ... Pickup torque limiter, 16 ... Shutter torque limiter, 17 ... Shutter lever, 19 ... Pickup roller, 20 ... ... Idle gear, 21 ... Electromagnetic clutch, 23 ... Document guide, 25
…… Guide trailing edge guide.

Claims (3)

(57) [Claims] A pickup torque limiter (14) is provided between a feed roller (12) fixed to a feed shaft (13) and the feed shaft (13) and rotatable about the feed shaft (13). ) With pickup bracket (11)
And the pickup bracket (11), which is connected to the feed roller (12) via an idle gear (20), and the feed shaft (13) and the feed roller (12)
And a separation roller bracket (6), which rotates with the rotation of the pickup bracket and presses against the lower surface of the document by the rotation of the pickup bracket (11), and a separation roller bracket (6) supported at one end and rotatable about its fulcrum O. A separation roller (8) rotatably provided at the other end and urged by a spring (5) to press against the feed roller (12);
A document pressure plate (2) having a lower surface pressing the upper surface of a document pressed against the pickup roller (19); a document pressure plate (2) rotatable around the fulcrum O; and positioned immediately before the separation roller (8) when setting a document. A shutter (1) having a stopper (1a) for abutting the leading end of a document, and a shutter torque limiter (16) rotatable around the feed shaft (13) and between the feed shaft (13). And a shutter lever (17) for rotating the shutter (1) such that the stopper (1a) rises and the document passes therethrough by rotating a predetermined angle with the rotation of the feed shaft (13). An automatic document feeder, comprising: 2. The automatic document feeder according to claim 1, further comprising a document leading edge guide (23) disposed immediately before a stopper (1a) of the shutter (1) and made of an elastic member. 3. A document trailing edge guide according to claim 1, further comprising a document trailing end guide disposed on the document table and capable of adjusting the position according to the length of the set document. Automatic document feeder.