JPS6164639A - Automatic original feeder - Google Patents

Abstract

PURPOSE:To make a pressure-contact surface between a feed belt and a roller selectable in an easy manner, by rotating one end of a crank member through bringing it into contact with the top of a copying machine, while transmitting this rotation to a double-feed preventive roller via a one-way clutch, and making it into stepping on a peripheral surface part of this roller. CONSTITUTION:When a projection 21 of a rocking lever 20 is pressed to a locking member on the top of copying machine and rotated clockwise, a crankshaft 11 is rotated counterclockwise as far as the specified angle via crank levers 18, 17 and 13. Therefore, with action of a compression spring 34 with the counterclockwise rotation of an engaging member 32 of a one-way clutch 30, a ball 35 serves as a wedge, making an outer ring 31 rotate counterclockwise as well. As a result, a peripheral surface of a double-feed preventive roller 4 to be pressed to a feed belt 4a moves in the counterclockwise direction, namely, in the reverse direction against original conveyance as far as the specified value whereby a new peripheral surface comes to be pressed to the feed belt 4a in consequence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a double-feed prevention device for an automatic document feeder that can be installed and used in a copying machine.

[Conventional technology]

Recording paper supplied to a copying machine is normally conveyed one by one from a paper feed cassette installed in the copying machine to an image transfer section.
A document image is recorded, and a double-feed prevention device is provided to prevent two or more recording sheets from being fed repeatedly.

Generally, the double feed prevention device is located immediately after the feed roller that carries out the recording paper from the paper feed cassette, and the double feed prevention roller is placed in a non-rotating state so that the feed belt wound around the driving and driven rollers is not rotated. The paper is configured to come into pressure contact with the pressure contact surface, and the recording paper shaped like the paper is carried into the pressure contact surface by a feed roller.

Therefore, the loaded recording paper is transported by sliding on the double-feed prevention roller by the feed belt, which has a greater frictional force than the double-feed prevention roller, but two sheets of recorded paper are overlapped. If this is the case, the frictional force between the feed belt and the double-feed prevention roller is greater than the frictional force between the recording paper surfaces, so the paper surface slips, and only the recording paper that is in contact with the feed belt is conveyed, preventing double-feeding. It looks like this.

In this way, the double-feed prevention roller usually has a tendency to wear its circumferential surface and become slippery due to the sliding of a large number of recording sheets. In some cases, a friction force greater than the friction force between the paper surfaces is required.

In order to minimize the deterioration of function due to wear of the double feed prevention roller, the double feed prevention roller is rotated by a small angle every time the required amount of copies are completed to reduce the amount of wear on the entire circumference. A method of dispersion has been proposed.

However, conventionally, this effect is based on the operation of attaching and detaching the paper feed cassette to and from the copying machine, so it has already been realized for the double-feed prevention device for recording paper in the copying machine body.
It has been considered difficult to apply this method to a document double-feed prevention device in an automatic document feeder that does not have a paper feeding capacity. For this reason, the automatic document feeder cannot be sufficiently effective because it is only rotated manually during periodic machine adjustments.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to enable a document double-feed prevention device in an automatic document feeder to consistently exhibit a stable double-feed prevention effect over a long period of time.

[Means for solving problems]

The present invention is characterized in that one end of the crank member protruding from the bottom of the document feeder rotates by touching the upper surface of the copying device, and the rotation is transferred to the double-feed prevention roller via a one-way clutch. The double-feed prevention roller is rotated in a direction opposite to the direction of document conveyance to slightly advance the curved portion of the double-feed prevention roller. The crank member is connected to the rotating shaft of a possible crank member via an all-one-way clutch, and the copying machine is enabled to operate, thereby rotating the crank member and rotating the double-feed prevention roller in the opposite direction of document conveyance. This is achieved by the copying machine's automatic document feeder, which is characterized by the automatic document feeder that stops at the same time.

〔Example〕

One embodiment of the automatic document feeder of the present invention is shown in Figure 1 and Figure 2.

In the figure, 1 is a document feed tray, 2 is a document guide plate, and the document placed thereon is sent to the double feed prevention device 4 according to the present invention by a feed roller 3 that has descended to the position shown by the broken line. The topmost single sheet is fanned and further conveyed, and after being reversed via intermediate conveyance rollers 5, it is conveyed with the document side facing downward to a document mounting table (not shown) of a copying machine by a conveyance belt 6. exposed to light.

The double-feed prevention device 4 has a function of separating documents by a sliding action between a well-known single-feed belt 4a and a double-feed prevention roller 4b that is in pressure contact with the double-feed prevention roller 4b. The rotation of the double-feed prevention roller 4b is maintained in a stopped state, but in the present invention, the double-feed prevention roller 4b is connected to the crank member 10, and the automatic document feeder 9 is connected to the copying machine. In the process of setting the roller to the operating state, the crank member 10 is actuated to rotate the double feed prevention roller by 1/1 angle and then stop again, so that the entire circumferential surface of the roller is used evenly. are doing.

Figure 2 shows the configuration of the crank member IO.

11! i. The crankshaft of the spear 1 is rotatably provided on an extension of the axis of the double-feed prevention roller 4b, and the engaging member 32 attached to the end thereof is an outer ring integrated with the double-feed prevention roller 4b. 31, and a ball 33 and a compression spring 34 are accommodated in a plurality of wedge-shaped spaces provided therebetween, forming a well-known Hall clutch. Further, a crank lever 13 of the spear 1 having a pin 14 at its tip is fixed to the crankshaft 11.

Reference numeral 16 denotes a crankshaft of fang 2 which is parallel to the crankshaft 11 and rotatable, and has a stepped portion at its end to which pin 14t of crank lever 13 is engaged. A lever 17 and a pin 19 at the tip of the other end.
The crank levers 18 of the fangs 3 are each fixedly attached.

Reference numeral 20 denotes a swinging lever pivotally attached to a side board (not shown) of the automatic document feeder, one end of which is in a position where it can lock the pin 19 of the crank lever 18, and the other end of which is in a position where the pin 19 of the crank lever 18 can be locked, and the other end is in a position where the pin 19 of the crank lever 18 can be locked. A window 40a provided in the bottom plate 40 of the device by forming a
It occupies a position that protrudes outside the twisting device.

The torsion spring 1 still attached to the crank lever 13
4, the crank 1) ζ 111° 16 and the crank lever 13° 17.
The pin 19 of No. 8 is held in the state shown in the figure because it is locked to the swing lever 20 which is in contact with the inner wall surface of the bottom plate 40 and is prevented from rotating counterclockwise.

Next, its effect will be explained.

The automatic document feed device is generally supported pivotally on the upper surface of the copying machine via a hinge, so that it can be set on the document placement surface with easy operation. As a result of this operation, the protrusion 21 of the swing lever 20 is simultaneously pressed against the fixed member on the upper surface of the copying machine and rotated clockwise, causing the crank lever ls, 17.
13, the crankshaft 11 is rotated counterclockwise by a predetermined angle.

Therefore, as the engaging member 32 rotates counterclockwise, the ball 35 acts as a wedge, causing the outer ring 31 to rotate counterclockwise as well.

As a result, the circumferential surface of the double feed prevention roller 4b that comes into contact with the feed belt 4a moves a predetermined amount in a counterclockwise direction, that is, in the opposite direction of the original feed, so that the circumferential surface of the double feed prevention roller 4b comes into contact with the feed belt 4a. However, the amount of movement is the same as that of the projection 21.
The setting is determined by the swinging angle of the swinging lever 20 due to the pressure.

When the document is transported in such a state, the double-feed prevention roller 4b receives clockwise frictional resistance due to the sliding of the document. It is impossible to rotate clockwise due to the weight of the device and the sticking resistance caused by magnet attraction, etc., so that the double feed prevention device 4 is able to perform its function.

Further, in order to release the setting of the automatic document feeder 61c, when the bottom plate 40 is moved away from the document placement surface, the swing lever 20 returns counterclockwise again by the action of the torsion Q spring 12. Returning to the illustrated state, since the retaining member 32 of the one-way clutch 30 rotates clockwise in this case, no wedging action occurs. Therefore, the double-feed prevention roller 4b
does not rotate in any direction and remains in pressure contact with the feeding dowel 4a.

As described above, in the automatic document feeder of the present invention, the circumferential surface of the double-feed prevention roller is automatically moved each time the device is used, so that the pressure contact surface with the feed belt can be moved without troublesome disassembly or adjustment. By setting an appropriate amount of movement, it is possible to utilize the entire circumferential surface without wasting it, so it is applicable not only to automatic document feeders but also to other double feed prevention devices. It provides unique functions.

〔Effect of the invention〕

The present invention provides an automatic document feeder that exhibits a stable double-feed prevention function over a long period of time without requiring any special preparation such as inspection or adjustment, and thereby can feed documents without feeding accidents. became.

[Brief explanation of drawings]

1 and 1 are block diagrams of an automatic document feeder according to the present invention. , f
Figure-2 is a perspective view of the main part. 4°... Double feed prevention device, 4a... Feed belt, 4b... Double feed prevention roller, 1o... crank member, 11.16°°... °Crankshaft, 1
2...Torsion spring, 13°17.18...
・Crank lever, 14.19...Bent hinge 20...Pa・Swinging lever, 21...Protrusion, 3o...One-way clutch, 40...Curved bottom plate, 40a...Sigh.

Claims (1)

[Claims] The double-feed prevention roller that presses against the document feed belt and the rotating shaft of the swingable crank member are connected via a one-way clutch, and the crank member is rotated by making the copying machine ready for operation. An automatic document feeder for a copying machine, wherein the double-feed prevention roller is rotated in a direction opposite to document conveyance and then stopped.