JPH0489732A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To stop a separating roller at the time of excessive load and prevent the damage to a driving system by driving the separating roller reversely rotating to the feed direction through a friction member and an one-way clutch. CONSTITUTION:When a sheet to be fed between a feed roller 1 and a separating roller 2 is one, the frictional force between the feed roller 1 and the sheet is larger than the frictional force with the separating roller 2, so that the sheet is fed in accordance with the rotation of the feed roller 1. When two or more sheets are fed, the sheets are returned by the reversely rotating separating roller 2 except the sheet in contact with the feed roller 1 to present the double feed. A gear 3 for driving the separating roller 2 rotates the separating roller 2 by pressing a frictional member 4 into contact with a disk 5 fixed to the separating roller 2 by a spring 6 and prevents its normal directional rotation by an one-way clutch 9. Thus, when an excessive load is added to the separating roller 2, a slippage is caused between the disk 5 and the frictional member 4 to stop the rotation of the separating roller 2, and a damage to a driving system is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet feeding device used in a paper feeding section that feeds sheet-like objects one by one into an apparatus.

[Industrial Field of Application] Conventionally, separating means provided in the paper feed section of a microfilm rotary camera to prevent double feeding of original documents has the following structure.

As shown in FIG. 3, a pair of rollers are arranged behind the document table, the upper roller 12 being a feed roller that rotates in the forward direction, and the lower roller 13 being a separation roller that rotates in the opposite direction. This pair of rollers has convex portions 12a and 13a that are different from each other, and it is necessary to adjust the distance between the feed roller 12 and separation roller 13 depending on the paper thickness of the document during paper feeding, and change the amount of overlap shown in FIG. 4. . For thin originals, the amount of overlap must be increased, and for thick originals, the amount of overlap must be reduced, but this is because the original is deformed and the protrusions 12a, 13 of the rollers are distorted as shown in Figure 5.
This is because thin originals with weak stiffness experience a large amount of deformation, while thick originals with strong stiffness do not deform thin originals.

Further, the separation roller 13 is fixed to a gear 14 (FIG. 3), so that the separation roller 13 always rotates during paper feeding.

The originals are fed one by one from the top, but if two or more originals try to enter the roller pair 12.13, the separation roller 13
Since the frictional force between the originals exceeds the frictional force between the originals, all originals except the top one are pushed back to prevent double feeding.

The hardness of the rubber of the feed roller 12 is lower than that of the separation roller 13, and conveying force is provided by increasing the frictional force between the document and the feed roller.

[Problems to be Solved by the Invention] However, in the conventional example described above, the separation roller 13 is directly connected to the drive source, so if a document that is thicker than the adjusted overlap amount is fed, the document will be pushed to the feed roller 12.
When the document is fed between the document and the separation roller 13, a strong roller pressure is applied to the document.

Therefore, the conveyance force by the feed roller 12 increases, and the stopping force by the separation roller 13 also increases, which places a high load on the drive system. This can cause various types of damage to the drive system.

Therefore, in order to feed paper ranging from thin paper to thick paper that is used in practical use, the distance between the feed roller and separation roller must be adjusted depending on the thickness of the document, so operators must be experienced. There was also the drawback that it could be lost.

[Means for solving the problem (and operation)] According to the present invention, a friction member and a one-way clutch are inserted in the drive system without directly driving the separation roller, and an overload is applied to the separation roller. By causing the friction member to slide and the separation roller to stop at this point, paper can be fed smoothly without overloading the drive source.

[Example] FIGS. 1 and 2 are drawings that best express the features of the present invention. In FIG. 1, 1 is a feed roller for feeding a document, and 2 is a roller that is rotated in reverse to prevent the document from being electrically fed. 3 is a gear that drives the separation roller 2, and 4 is a gear that drives the separation roller 2.
5 is a friction member, 5 is a disk for pressing the friction member 4 against the gear 3, 6 is a spring, 7 is an axial direction regulating member, 8 is a gear driving the gear 3, 9 is a part of the separation roller 2 in the forward direction The one-way clutch 10 is a housing of the one-way clutch, and the housing is fixed so as not to rotate.

The gear 3 and the friction member 4 are rotatable relative to the separation roller 2, and only the disk 5 is fixed to the separation roller 2 in the rotational direction.

Further, the rubber hardness of the feed roller 1 and the separation roller 2 is lower in the feed roller 1, and the frictional force with the document is greater. Furthermore, the convex portions 1a of the feed roller 1 and the convex portions 2a of the separation roller 2 are located at different positions.

FIG. 2 is a side view, and reference numeral 11 denotes a document mounting table on which a document P is placed and guided to the feed roller 1. As shown in FIG.

When the original P is placed on the original plate 11, the original P slides down on the original plate 11 due to its own weight and is introduced into the feed roller l. At this time, if only one document enters the feed roller 1, the frictional force between the feed roller 1 and the document is greater than the separation roller 2.
is larger than the frictional force of the original, so the original is moved to feed roller 1.
Paper is fed as the machine rotates. If two or more originals try to enter the feed roller 1, the separation roller 2, which is rotating in reverse, will push them back, except for the topmost document that is in contact with the feed roller 1, and eventually the topmost document will be pushed back. Only one original is fed, and when the trailing edge of the -th original passes through the feed roller 1, the second original is introduced by the feed roller 1 and fed in the same manner.

In the case of a thick document, even if the gear 3 is rotating, the document is separated by being introduced by the feed roller 1 rather than by the friction force generated by the spring 6 pressing the disc 5 against the friction member 4. When the load applied to the roller 2 becomes larger, a slip occurs between the gear 3 and the friction member 4, or between the friction member 4 and the disk 5, and the rotation of the separation roller 2 is stopped. The thickness of the paper at which the separation roller stops rotating when the document is fed can be determined arbitrarily by changing the spring force of the spring 6 or by changing the material of the friction member 4. Can be adjusted.

Further, since the one-way clutch 9 is attached to the separation roller 2, the separation roller 2 never rotates in the direction in which the documents travel, so there is no need to worry about double feeding.

Generally, when the amount of overlap is the same, the restraining force of the separation roller 2 against the document is smaller when the separation roller 2 is stopped than when it is rotating in reverse. Therefore, since the document conveyance force is large, thicker documents can be fed in this embodiment in which the separation roller 2 is stopped for the same amount of overlap, compared to the case where the separation roller always rotates in reverse as in the conventional example.

Therefore, if you adjust the distance between feed roller 1 and separation roller 2 to avoid double feeding with the thinnest originals fed by this device, the distance between feed roller 1 and separation roller 2 will be smaller for thicker documents. It is possible to feed paper without readjusting the spacing.

Not only in the case of thick originals, but also in the case of thin originals, when multiple sheets of originals are sandwiched between the feed roller 1 and the separation roller 2 in a wedge shape, the load on the separation roller 2 increases and the separation roller Since the rotation of 2 is stopped, paper can be fed without applying excessive force to the drive source.

As described above, even if the distance between feed roller 1 and separation roller 2 is adjusted to prevent double feeding of thin documents, even if a thick document is fed, a load above a certain level is applied to separation roller 2. Then, the separation roller 2 stops rotating, so that paper can be fed smoothly without applying excessive force to the drive system.

[Effects of the Invention] As explained above, a friction member and a one-way clutch are inserted in the middle of driving the separation roller, and when a load above a certain level is applied to the separation roller, the friction member is slid to stop the separation roller. This prevents overload from being applied to the transmission system in the middle of the drive source, such as the motor, and prevents damage to the drive system.

In addition, since the separation roller stops due to the load, the document stopping force exerted by the separation roller is reduced, and even thick documents can be fed even with a large amount of overlap, allowing paper to be fed from thin to thick documents without adjusting the amount of overlap. It also has the effect of being able to.

Furthermore, since there is no need to adjust the amount of overlap, there is an advantage that the operation can be performed by anyone, not only those who have experience in operating a rotary camera.

[Brief explanation of drawings]

Fig. 1 is a front view of a paper feeding system embodying the present invention, Fig. 2 is a side view of Fig. 1, Fig. 3 is a drawing showing a conventional example of the paper feeding system, and Fig. 4 is a side view of Fig. 3. Figure 5 is a diagram showing a state in which a document is placed in the paper feed system. 1... Feed roller 2... Separation roller 3... Gear 4... Friction member 5... Disk 6... Spring 7... Axial direction regulating member 9... One-way clutch

Claims (1)

[Claims] Sheets are fed one by one into a device that has a pair of rollers that rotate in the forward and reverse directions with respect to the feeding direction, with the convex and concave portions facing each other, and the concave and convex portions facing each other so as not to touch each other. A sheet feeding device characterized in that a roller rotating in a direction opposite to the feeding direction is driven via a friction member and a one-way clutch.