JPH0241487B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic paper feeder that distinguishes and feeds stacked sheets one by one.

Conventional structure and its problems In a facsimile machine, an automatic paper feeder is used to feed originals stacked on a document table one by one, starting from the bottom, and feed them to the reading unit. There is a torque limiting system in which paper is fed between a rotationally driven paper feed roller and a reversing roller that is rotationally driven in the opposite direction to the paper feeding direction via a power transmission system having torque limiting means.

In this automatic paper feeder, if there is no paper or only one sheet between the paper feed roller and the reverse roller, the rotational force transmitted from the paper feed roller to the reverse roller is large, so the reverse roller also If two or more sheets of paper are interposed between the paper feed roller and the reversing roller, the rotational force transmitted from the paper feeding roller to the reversing roller is small, so the reversing roller rotates in the opposite direction to the paper feeding direction, leaving only one sheet of paper in contact with the paper feeding roller and transporting the other sheets in the opposite direction to the paper feeding direction. Through such operations, sheets are fed one by one.

However, with such conventional automatic paper feeders,
There have been problems in that the setting range of the torque limit value of the torque limit means is narrow, making it difficult to set the torque limit means, and malfunctions are likely to occur due to fluctuations in the torque limit value over time.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems, and expands the setting range of the torque limit value of the torque limit means, facilitates the setting of the torque limit means, and prevents malfunctions due to fluctuations in the torque limit value over time. It is an object of the present invention to provide an automatic paper feeder with further improved ease of assembly.

Structure of the Invention The present invention provides a plurality of reversing rollers rotatably provided on a first shaft for discriminatingly feeding sheets in cooperation with a paper feed roller, and between the first shaft and the reversing rollers. Torque limiting means is interposed, and the first shaft is supported movably in a direction in which the reversing roller is brought into contact with and away from the paper feed roller in a groove-shaped holding means having an opening at the upper part, and the first shaft is rotatably driven. A power transmission means for transmitting the rotational force of a second shaft to the first shaft is configured to connect the first shaft to the second shaft at both ends thereof, and simultaneously transmit the rotational force to the reversing roller. By configuring the first shaft to apply a force in the direction of pressing the paper feed roller,
The aim is to achieve the above objectives.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a partially omitted schematic plan view of an automatic paper feeder according to an embodiment of the present invention, FIG. 2 is a partially omitted schematic side view of the same automatic paper feeder, and FIG. -' line schematic cross-sectional view. In these figures, the reversing rollers 1a and 1b are loosely inserted into the shaft 3 through sleeves 2a and 2b made of Jyuracon (registered trademark No. 970488), and are rotatable and shaft-aligned with the sleeves 2a and 2b. 3 is movably supported in the longitudinal direction. Friction plates 4a, 4b made of phenol are fixed to both ends of the shaft 3, and pulleys 5a, 5b are further fixed to the outside thereof. Also axis 3
are provided with coil springs 6 for pressing the sleeves 2a, 2b against the friction plates 4a, 4b. The coil spring 6, together with the friction plates 4a, 4b and the sleeves 2a, 2b, constitutes a torque limiter interposed between the shaft 3 and the reversing rollers 1a, 1b. Both ends of the shaft 3 are supported by support plates 7a and 7b.
a vertical groove 8 formed in the groove and having an opening at the top;
It is held rotatably and vertically movably within the chambers a and 8b. Note that during assembly, the shaft 3 is inserted through the opening.

A shaft 9 rotatably supported by support plates 7a and 7b
Pulleys 10a and 10b are fixedly installed.
Belts 11a and 11b are passed between the pulleys 10a and 10b and the pulleys 5a and 5b. These pulleys 5a, 5b, 10a, 10b and belts 11a, 11b constitute a power transmission system for transmitting the rotational force of the shaft 9 to the shaft 3. Note that the belts 11a and 11b are elastic belts.

In addition, as shown in FIG. 2, the reversing roller 1
Paper feed rollers 12a and 12b are placed below a and 1b.
(12b is not shown) is provided.
The rotating shaft 13 on which the paper feed rollers 12a and 12b are fixed, the rotating shaft 1 of the shaft 9 and the motor 14.
A belt 16 is passed between the motor 14 and the motor 14.
By operating the shaft 9 and the rotating shaft 13
are rotated at the same time. Next, the operation will be explained. When the motor 14 is activated, the paper feed rollers 12a and 12b are driven to rotate in the direction of the arrow 18, and at the same time, the shaft 9 is driven to rotate in the direction of the arrow 19. The rotational force of the shaft 9 is transmitted to the shaft 3 via the belt 11a and the pulleys 5a, 5b, 10a, 10b, and the shaft 3 rotates in the direction of the arrow 20. The rotational force of the shaft 3 is applied to the friction plates 4a, 4b and the sleeve 2 of the torque limit means, which are in frictional engagement with each other.
It is transmitted to the reversing rollers 1a and 1b via a and 2b.

Here, as shown in FIG.
If there is any paper between a and 12b, or if no paper is present, the paper feed roller 12
The rotational force transmitted from a, 12b to the reversing rollers 1a, 1b becomes larger than the rotational force transmitted from the shaft 3 to the reversing rollers 1a, 1b via the torque limit means. In other words, a torque exceeding the torque limit value is applied to the torque limit means, the torque limit means idles, and the reversing rollers 1a and 1b move along the arrow line 2 in accordance with the rotation of the paper feed rollers 12a and 12b.
It is rotated in the opposite direction to 0. As a result, the paper 21 interposed between the rollers is transported in the paper feeding direction indicated by the arrow 22.

On the other hand, when a plurality of sheets of paper 21 are interposed between the paper feed rollers 12a, 12b and the reverse rotation rollers 1a, 1b, the rotational force transmitted from the paper supply rollers 12a, 12b to the reverse rotation rollers 1a, 1b is , is smaller than the frictional force generated between the friction plates 4a, 4b and the sleeves 2a, 2b. In other words, the torque value applied to the torque limit means becomes smaller than the torque limit value. As a result, the reversing rollers 1a and 1b are rotated in the direction of the arrow 20, and the paper feed roller 12
The lowest paper that comes into contact with the rollers a and 12b is sent in the paper feeding direction, but the remaining papers are sent back by the reversing rollers 1a and 1b in the opposite direction to the paper feeding direction.

Now, if the contact pressure between the paper feed rollers 12a, 12b and the reversing rollers 1a, 1b is large, the rotational force transmitted from the paper feeding rollers 12a, 12b to the reversing rollers 1a, 1b becomes large; If is small, the transmitted rotational force will be small. Therefore,
This contact pressure is an important factor in setting the torque limit value.

FIG. 4 is a diagram showing the relationship between such contact pressure and torque limit value. In this figure, the shaded area C
indicates an area where the automatic paper feeder can distinguish and feed sheets one by one. For example, if the contact pressure is constant as shown by the straight line 23, the range of torque limit values that allows normal automatic paper feeding is A.

On the other hand, in this embodiment, the shaft 3 is provided with grooves 8a and 8b.
The reversing rollers 1a,
The rotational force of the rotating shaft 9 provided on the front side of 1b is transferred to the belt 1.
Since the power transmission mechanism is configured so that the power is transmitted to the shaft 3 by 1a and 11b, when the reversing force is transmitted, the direction in which the reversing rollers 1a and 1b are pushed against the paper feed rollers 12a and 12b as a component of the transmitted force is force is applied to the reversing rollers 1a and 1b. A similar force is
It also occurs due to friction between the shaft 3 and the grooves 8a, 8b.
Therefore, the reverse rotation rollers 1a, 1b and the paper feed roller 12
a, 12b and the contact pressure is the resultant force of the pressing force due to the component of this transmitted force and the own weight of the reversing rollers 1a, 1b. The pressing force due to the component force of this transmitted force has a characteristic that it increases as the torque limit value increases. Furthermore, between the phenol friction plates 4a, 4b and the Duuracon sleeves 2a, 2b, which constitute the torque limit means, the dynamic friction coefficient is larger than the static friction coefficient, and the relative rotational speed of the shaft 3 and the reversing rollers 1a, 1b is The larger the difference, the greater the frictional force between the friction plates 4a, 4b and the sleeves 2a, 2b. Therefore, in the case of this example,
The contact pressure is proportional to the torque limit value, as shown by the solid line 24 in FIG.

Therefore, the setting range of the torque limit value that allows normal automatic paper feeding is B, which is obviously wider than range A, and therefore the setting of the torque limit means is facilitated. The torque limit value is mainly determined by the elastic force of the spring spring 6, but if the setting range of the torque limit value is widened as described above, the accuracy conditions for the spring spring 6 are relaxed, and the torque limit means can be adjusted without having to be adjusted. .

Note that the lighter the reversing rollers 1a and 1b, the more
The setting range of the torque limit value is expanded and the setting becomes easier.

Although one embodiment has been described in detail above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the friction plates 4a, 4
b and the materials of the sleeves 2a and 2b are selected, but it is also possible to change the material to a material whose dynamic friction coefficient is less than the static friction coefficient. However, in order to widen the setting range of the torque limit value, it is advantageous to select the material as in the above embodiment.

Further, a rotating shaft 9 is provided on the paper discharge side, and a pulley 5a,
5b and the pulleys 10a, 10b may be replaced with gears that mesh with each other (the rotating direction of the rotating shaft 9 is the same as in the above embodiment).

Further, the rotating shaft 9 may be rotated by a motor separate from the motor 14.

Effects of the Invention As described above, according to the present invention, the setting range of the torque limit value is widened, so the setting of the torque limit means can be made easier or no adjustment is required, and it is also possible to prevent the torque limit means from changing over time. Effects such as being able to reliably prevent malfunctions can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially omitted schematic side view of an automatic paper feeder according to an embodiment of the present invention, FIG. 2 is a partially omitted schematic plan view of the same automatic paper feeder, and FIG. 3 is the same as that shown in FIG. 1.
4 is a sectional view taken along the line '' and is a diagram showing the relationship between torque limit value and contact pressure. 1a, 1b...Reverse roller, 2a, 2b...Dyuracon sleeve, 3...Shaft, 4a, 4b...
Phenol friction plate, 5a, 5b, 10a, 10
b...Pulley, 6...Coil spring, 7a, 7b...
...Support plate, 8a, 8b...Groove, 9...Rotating shaft, 1
1a, 11b, 16...belt, 12a, 12b
... Paper feed roller, 13 ... Axis, 14 ... Motor,
21...Paper.

Claims (1)

[Claims] 1. Paper feed roller 12 that is rotationally driven in the paper feeding direction.
a, 12b, reversing rollers 1a, 1b that contact the upper part of this paper feeding roller with their own weight and are driven in the opposite direction to the paper feeding direction via torque limiters 4a, 4b, and moving these reversing rollers 1a, 1b up and down. Groove-shaped holding means 8a and 8b that are held freely and rotatably and have an opening at the top; a driving means 14 that drives the paper feed rollers 12a and 12b and the reversing rollers 1a and 1b; and driving of this driving means. force to the paper feed roller 12
a, 12b and driving force transmitting means 11a, 11b; 16 for transmitting to the reversing rollers 1a, 1b, the driving force transmitted from the driving force transmitting means 11a, 11b;
An automatic paper feeder characterized in that a force is generated in a direction that presses the paper feed rollers 12a and 12b.