JPH03200637A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To reduce the generation of tensile vibration of a sheet and to prevent the generation of vibration noise of a sheet guide connected to a sheet by providing a friction reducing means to reduce the compression force of a sheet guide brought into pressure contact with a sheet feeding means on the upper stream side and reduce a frictional resistance force. CONSTITUTION:When a sheet P at a topmost layer is conveyed by a sheet feeding member 1 and brought into contact with the nip parts of conveying rollers 9a and 9b to produce a given slack, a solenoid 20 is turned ON simultaneously with the stop of a sheet feeding member 1, and rotation of the conveying rollers 9a and 9b is started. Through turning ON of the solenoid 20, upper and lower part pieces 16b and 16c of a lever 16 are both lowered and the upward energizing forces of a tensile spring 17 and a compression spring 18 are reduced, whereby the press forces of a friction member 5, mounted to a sheet guide 6, and a middle plate 12 are reduced. Thus, frictional resistance exerted on the sheet P at a topmost layer is reduced to prevent the generation of vibration exerted on the sheet P.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention relates to sheet feeding devices used in copying machines, laser beam printers, etc., and specifically relates to means for reducing the resistance of sheet separating devices during sheet feeding. .

(b) Prior Art Conventionally, some sheet feeding devices used in copying machines and laser beam printers are constructed as shown in FIGS. 3 and 4.

Reference numeral 1 denotes a paper feeding member fixed to a horizontally projecting shaft 3 perpendicular to the conveying direction of the sheet P from a driving means 2 provided in a copying machine. Shape roller members 4a and 4b are rotatably supported. The paper feeding member 1 has a cross section cut along a plane perpendicular to the shaft 3, and has a cylindrical portion 1a with a slightly larger diameter than the roller members 4a and 4b, and a radius that gradually decreases from the cylindrical portion 1a and becomes slightly smaller at the center of the cylindrical portion. It is made of an elastic body with a large coefficient of friction.

A guide member 6 supporting the upstream end of the friction member 5, which is always in contact with the roller members 4a and 4b, is pivotally supported by a fixed pin 6a, and is urged upward by a tension spring 7. It is adapted to come into pressure contact with the roller members 4a and 4b. An upper guide member 8 is fixedly installed opposite to the upper part of the downstream side of the guide member 6, and conveying rollers 9a, 9 are placed close to the downstream ends of the guide members 6, 8.
b are fixed to shafts 10a and 10b protruding from the drive means 2 in parallel to the shaft 3. The friction coefficient of the friction member 5 is smaller than the friction coefficient of the paper feeding member 1, and 6 larger than the friction coefficient between the sheets P.

Further, the sheet P whose downstream end is in contact with the roller members 4a and 4b is placed on the regulating plate 11 in the cassette 11 installed in a copying machine or the like.
It is laterally regulated by a and llb, and is urged upward by the middle plate 12 and loaded. Note that 13 is a compression spring that urges this intermediate plate 12 upward.

Thus, when the start key is pressed in the standby state (the state shown in FIG. 3) in which the cutout 1b of the paper feed member 1 faces downward and is not in contact with the sheet P (the state shown in FIG. 3), the paper feed member 1 moves clockwise. When the cylindrical portion 1a contacts the surface of the uppermost sheet P of the cassette 11, a frictional force is generated between the sheet P pressurized by the compression spring 13 and the sheet P next to this sheet P is moved by the friction member. 5, the top sheet P
The best sheet P overcomes the frictional force between the sheet P and the next sheet P.
is separated and advances to the downstream side, and after the tip comes into contact with the nip portion of the conveying rollers 9a and 9b, a slack 14 is generated in this sheet)-P as shown in FIG. 5, and the skew is corrected. .

When a predetermined amount of slack occurs, the paper feeding member 1 returns to the state shown in FIG. 3, stops, and enters a standby state.

Then, the conveyance rollers 9a and 9b rotate, and the sheet P is conveyed to the next process (inside the main body of the copying machine, etc.).

At this time, when the second sheet P from the lowest is separated from the lowest sheet P, what blocks the lowest sheet P is the intermediate plate 12 and the friction member 5, and the intermediate plate 12 is separated from the lowest sheet P.
Generally, the coefficient of friction is smaller than that of the lowest sheet P, and the lowest sheet P is easily dragged by the second sheet P from the lowest. Therefore, the frictional force of the middle plate 12 is increased to stabilize the separation ability from the lowest sheet P. Separation sheet 1 is placed at the downstream end of the intermediate plate 12 to
Install 5.

(C) Problems to be Solved by the Invention However, when the sheet P is conveyed by the conveyance rollers 9a and 9b and the slack 14 is removed, it is pressed against the friction member 5 by the roller members 4a and 4b as shown in FIG. ,
The sheet P having frictional resistance is pulled by the transport rollers 9a and 9b.

Then, the following two problems arise.

(2) The sheet P, which is an elastic body pulled by a frictional force, vibrates because the tensile force changes from static friction to dynamic friction. Due to the vibrations caused by so-called stick and slip development, the guide member 6 and the like connected to the sheet P vibrate, generating vibration noise.

(2) Shortening the life of the conveying rollers 9a, 9b, friction member 5, etc. that are subjected to load and conveyed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet feeding device that reduces the frictional resistance force exerted on a sheet by an upstream sheet feeding means when the sheet is conveyed by a downstream sheet feeding means. .

(d) Means for solving the problem The present invention has been made in view of the above circumstances, and includes:
For example, referring to FIG. 1, there are sheet feeding means (1, 5) on the upstream side in the conveying direction of the sheet (P), and at least one sheet conveying means (9a, 9b) on the downstream side. and when the downstream sheet conveying means (9a, 9b) conveys the sheet (P), the upstream sheet feeding means (1, 5) causes friction against the sheet (P). In the sheet feeding device that provides resistance, frictional force reducing means (16) reduces the pressing force of the sheet guide (6) that presses against the upstream sheet feeding means (1, 5) to reduce frictional resistance force. , 19, 20).

(E) Effect Based on the above configuration, the sheet (P) is fed by the upstream sheet feeding means (1, 5), and the fed sheet CP) is fed to at least one downstream sheet. When conveyed by the sheet conveying means (9a, 9b) on the side, the sheet feeding means (1, 5) on the upstream side applies frictional resistance to the sheet CP). At this time, the frictional force reducing means (16, 19, 20) reduces the pressing force of the sheet guide (6) that presses against the upstream sheet feeding means (1°5) to reduce the frictional resistance of the sheet. Reduce force.

Note that the symbols in parentheses are just examples and do not limit the configuration in any way.

(f) Example Hereinafter, the present invention will be explained in detail with reference to FIG.

Components having the same structural functions as those of the conventional example shown in FIGS. 3 and 4 are given the same reference numerals, and explanations thereof will be omitted.

The mx-shaped lever 16 is supported by a fixed shaft 16a,
A tension spring 17 is interposed between the end of the upper piece 16b of the lever 16 and the guide member 6, and the guide member 6 is biased upward. Further, a compression spring is interposed between the end of the lower piece 16C of the lever 16 and the downstream end of the middle plate 12, and the middle plate 12 is biased upward.

Further, a permanent magnet 19 is attached to the upper surface of the middle part of the lower piece 16c of the lever 16, and a solenoid 20 is fixedly installed opposite to the -E direction of this permanent magnet 19. When this solenoid 20 is off, the permanent magnet When the solenoid 19 is attracted to the iron core of the solenoid 20 or turned on, a repulsive magnetic force is generated against the permanent magnet 19, causing the permanent magnet 19 to fall.

Further, a stopper 21 is fixedly provided below the lower piece 16c of the lever 16 to prevent the lower piece 16c from falling.

Thus, when the top layer sheet P is conveyed by the sheet feeding member 1 and its tip abuts the nip portion of the conveying rollers 9a and 9b to form a predetermined slack 14, the shaft 3 stops.
That is, at the same time as the paper feeding member 1 stops, the solenoid 20 is turned on and the conveying rollers 9a and 9b start rotating.

Therefore, the ends of both the upper piece 16b and the lower piece 16c are lowered, and the upward biasing force of the tension spring 17 and the compression spring 18 is reduced, so that the pressing force of the friction member 5 and the middle plate 12 is reduced. , the frictional resistance exerted on the top layer sheet P is reduced.

However, at this time, the sheet P that is in contact with the top layer sheet P
In order to provide the springs 17 and 18 with a biasing force that maintains enough frictional force to prevent entangled movement (double feeding), the biasing force is adjusted by the position of the stopper 21. As a result, the static frictional force and the kinetic frictional force become smaller, and the fluctuations in the frictional force between the two become smaller, making it possible to prevent vibrations against the seat P, thereby preventing vibrations and vibration noise of the members connected to the seat P. Ru.

Next, another embodiment will be described with reference to FIG.

In this embodiment, the stopper 21 for adjusting the urging force of the springs 17 and 18 is omitted. A plate-shaped sensor lever 22 that automatically falls into the hole 12a of the middle plate 12 is pivotally supported by a fixed pin 22a, and when it falls, it no longer blocks the interrupter 23 and the seat P 12, an interrupter 23 is fixedly installed so as to shut off the interrupter 23. By doing this, when the final (lowest) sheet P runs out and falls into the sensor lever 22 or the hole 12a of the middle plate 12 and the interrupter 23 is turned on, the solenoid 20 is turned on and the permanent magnet 19 falls. As a result, the upper part 16b and the lower piece 16c of the lever 16 descend to the lowest position, and press the friction member 5, the separation sheet 15, or the roller members 4a, 4b slightly or do not press the sheet P.
The frictional resistance will be very small or zero.

As a result, since there is no other sheet P (below) on the bottom sheet P, the bottom sheet P is not only pressed against the friction member 5 over its entire surface but also against the separation sheet 15. It is subject to the strongest frictional resistance, stationary, moving, i.e. stick,
The one that receives the largest amount of variable slipping load (when the sheet P is on the lower side, the front end of the sheet P covers a part of the friction member 5 and also covers the separation sheet 15) is The maximum vibration and vibration noise can be eliminated to reduce it to little or no vibration.

(g) As described in the detailed description of the invention, according to the present invention, the at least one
When the sheet is conveyed by the downstream sheet conveyance means, the frictional resistance force applied to the sheet by the upstream sheet conveyance means is reduced by the frictional resistance reducing means, so that sticks and slips caused by friction are reduced. In order to reduce the tensile vibration of the sheet that is induced by the phenomenon, it is possible to prevent the vibration and vibration noise of the sheet kite etc. connected to the sheet, and
By reducing the load due to the frictional resistance, the life of the downstream sheet conveying means and the upstream sheet feeding means can be extended.

[Brief explanation of drawings]

FIG. 1 is a vertical side view showing an embodiment of the present invention, FIG. 2 is a vertical side view of another embodiment, FIG. 3 is a vertical side view of a conventional sheet feeding device, and FIG. 4 is a perspective view thereof. FIG. 5 is a perspective view showing the sheet in a sagging state, and FIG. 6 is a longitudinal sectional side view showing the sheet in a stretched state. 9a, 9b...Downstream sheet conveyance means (conveyance roller) 16,19.20...Frictional force reduction means (
Lever Permanent magnet, solenoid) P...Seat

Claims (1)

[Claims] 1. It has an upstream sheet feeding means and at least one downstream sheet transporting means in the sheet transporting direction, and when the downstream sheet transporting means transports the sheet,
In a sheet feeding device in which the upstream sheet feeding means applies frictional resistance to the sheet, a frictional force that reduces a frictional resistance force by reducing a pressing force of a sheet guide that is in pressure contact with the upstream sheet feeding means. A sheet feeding device characterized by being provided with a reduction means.