JPH03152038A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent the generation of sheet powder from a recording sheet fed to the downstream side by providing a means to separate a high friction part against an energizing force exerted on the high friction part in linkage with operation of a resist roller by a resist roller operating means during operation of the resist roller. CONSTITUTION:A high friction pad 4 is made of urethane rubber and mounted to the one end part of an inner pad holder 7 having hardness of, for example, 65 deg.. A low friction pad 14 is also made of urethane rubber and has hardness of, for example, 90 deg.. The low friction pad 14 is mounted to the end part of an outer pad holder 10 disposed to the outside of the inner pad holder 7. The high friction pad 4 is rotatably mounted as a high friction part separating means to the operation part of a solenoid 13. Through operation of the solenoid 13, the high friction pad 4 is separated away from a feed roller 2 in linkage with operation of resist rollers 5 and 5 only during the passage of a recording sheet through a resist front switch 6, and frictional resistance between the high friction pad 4 and a feed roller 2 is reduced.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a paper feeding device, and more specifically, in an image forming apparatus such as a copying machine or a facsimile, a transfer unit transfers recording sheets one by one from a storage case. This paper relates to a paper feeding device that supplies paper to a paper feeder.

(B) Conventional technology A paper feeding device in an image forming apparatus conventionally includes a paper feeding roller that rotates in contact with the surface of the recording paper in order to feed the recording paper sheet one by one from the storage case to the transfer section; A paper feeding device is used that uses a friction member that presses the back side of the recording paper, and separates and feeds the recording paper by the frictional force between the paper feeding roller and the friction member.

In this type of paper feeding device, during paper feeding, the friction member is always pressed against the paper feeding roller with the same pressure.

(C) Problems to be Solved by the Invention In general, according to a paper feed device equipped with a paper feed roller and a friction member, the friction member rubs the recording paper and feeds the recording paper sheet one by one to the transfer unit. Paper dust is generated. This paper powder has an adverse effect on the next process. That is, there are adverse effects such as paper dust clogging the blade during cleaning and paper dust adhering to the surface of the photoreceptor drum during transfer.

Such an adverse effect has been a particular problem in the above-mentioned paper feeding device in which the friction member is always in pressure contact with the paper feeding roller with the same pressure during paper feeding, because paper powder is generated significantly.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a paper feeding device that can reduce the generation of filter paper powder during paper feeding and eliminate the above-mentioned adverse effects.

(d) Means for Solving Problem R and Its Effects This invention provides a paper storage case that accommodates a plurality of sheets of recording paper one on top of the other, a paper feed roller, and a paper storage case that is located at the top of the paper storage case. A paper pressing means presses the upper surface of the upper recording paper to bring it into contact and sends out the recording paper, and a paper pressing means presses the recording paper being sent out against a paper feed roller and is biased to apply frictional resistance to the lower surface of the recording paper. A friction member, a pair of registration rollers disposed downstream of the paper feed roller, and a pair of registration rollers disposed upstream near the registration rollers that register only while the recording paper fed from the paper feed roller passes through. and a registration roller operating means for operating the rollers, the friction member comprising a high friction part and a low friction part having a lower friction coefficient than the high friction part, and the high friction part covers an intermediate area of the paper feed roller. The low-friction portion presses both end regions of the paper feed roller in a separable manner, and the low-friction portion is disposed near the friction member, and when the registration roller is operated by the registration roller actuating means, This paper feeding device is provided with a high-friction part separating means that is interlocked with the operation of the high-friction part and separates the high-friction part against the urging force applied to the high-friction part.

That is, in the paper feeding device of the present invention, the friction member, which was conventionally made of one material, is made up of a high friction portion and a pair of low friction portions having two high and low WL engagements, and the high friction portion is It is characterized in that it is pressed by the paper feed roller so that it can be separated, and that a high friction part separation means, which was not available in the past, is provided near the friction member. The high friction part separating means attempts to separate the high friction part from the paper feed roller in conjunction with the operation of the registration rollers only while the recording paper is passing through the registration roller operation means.

Here, the combination of the high friction part and the low friction part is, for example, urethane rubber (high) with a hardness of 65° and a hardness of 90°.
urethane rubber (low), foamed urethane rubber (high) with a hardness of 1f32°, and urethane rubber (low) with a hardness of 80".

Thus, in this paper feeding device, the high friction part of the friction parts t0 is separated from the paper feed roller for a predetermined period of time by the high friction part separating means, so that the frictional resistance between the friction member and the paper feed roller is reduced. This makes it possible to prevent the generation of paper dust from the recording paper that is sandwiched between the paper feed roller and the friction member and sent to the downstream side.

(E) Implementation a1 The present invention will be described in detail below based on one embodiment shown in the drawings. Note that this invention is not limited to this.

In FIGS. 1 to 4, the paper feed device IP includes a paper storage case l, a paper feed roller 2, a paper pressing means 3, a high friction pad 4 as a high friction part of the friction members, and a low friction part of the friction members. It is provided with a low friction pad 14 as a friction part, a pair of registration rollers 5, and a pre-registration switch 6 as registration roller actuating means.

The paper storage case 1 stores a plurality of recording sheets in a stacked manner. The paper feed roller 2 has the role of rotating while contacting the upper surface of the stored recording paper to feed out the recording paper. The paper pressing means 3 presses the recording paper in the paper storage case l against the paper feed roller 2 to avoid contact with the recording paper.

This paper pushing means 3 is located at the bottom [3a] of the paper storage case l.
And push up this bottom plate 3a? $3b and
It consists of a first coil spring 3c that always urges this push-up ff1H3b upward.

The high friction pad 4 is made of urethane rubber and has a hardness of 65
°. This high friction pad 4 is provided at one end of the inner pad holder 7 by one inch. The inner pad holder 7 is supported by a rotating shaft 9 on the pond end side. Further, a second coil spring 8 is attached to the end of the inner pad holder 7 as a biasing means. The high friction pad 4 is biased upward and to the right by the second coil spring 8 via the inner pad holder 7, and is brought into pressure contact with the paper feed roller 2 so as to be separable.

The low friction pad 14 is made of urethane rubber and its hardness is 9.
0'. This low-friction pad 14 is attached to an end of an outer pad holder 10 disposed outside the inner pad holder 7. The outer pad holder 10 is supported by a rotating shaft 11 at an intermediate portion. Also, the outer pad holder 10
A third coil spring 12 as a biasing means is attached to an intermediate portion of the spring. And by the third coil spring 12,
The low-friction pad 14 is urged upward and to the right via the outer pad holder 10, and is brought into pressure contact with the paper feed roller 2 in a manner that cannot be separated from the paper feed roller 2.

The high friction pad 4 is rotatably attached to the operating part of a solenoid 13 serving as a high friction part separating means. That is, the solenoid 13 is connected to the switch 6 before the recording paper is registered.
The high friction pad 4 is separated from the paper feed roller 2 only while the paper is passing through the paper feed roller 2 in conjunction with the operation of the registration rollers 5.

The operation of this paper feeding device will be explained below.

In FIGS. 3 and 5, when the first sheet feed signal is input manually and the paper feed roller 2 is turned on and its rotation shaft rotates, the paper feed roller 2 picks up the recording paper in the paper storage case l. This recording paper consists of high friction pad 4 and low friction pad 1.
The registration roller pair 5.5 is made into one sheet at the nip with 4.
sent to.

When the leading edge of the recording paper reaches the pre-registration switch 6, the switch 6 is turned on (1+ time). And 1. The leading edge of the paper is brought into contact with the pair of registration rollers 5 and 5 between the mustards 7 to align the leading edge. When the alignment of the leading edge of the recording paper is completed, the drive of the paper feed roller 2 is turned off (at time C2). At this time,
Registration roller pair 5.5 starts rotating (11 o'clock). At the same time, the solenoid 13 is turned ON, and its operating portion pulls the inner pad holder 7, as shown in FIG. -Then, the high friction pad 4 separates from the paper roller 2. At this time, the low friction pad 14 remains pressed against the paper feed/roller 2, thereby preventing the second sheet of recording paper from advancing.

Thereafter, the pair of registration rollers 5 and 5 transport the recording paper without passing through the next process. During this time, the paper feed roller 2 is caused to follow the recording paper by holding a one-way clutch on its rotating shaft.

After the pair of registration rollers 5 and 5 feed out the first sheet of recording paper with the high friction pad 4 separated from the paper feed roller 2, the switch 6 is turned OFF during the interval for feeding the recording sheet of the second outlet. , the registration roller pair 5.5 stops rotating, and at the same time, the solenoid 13 turns OFF (at time ts). After that, the second sheet feed signal is input and the paper feed roller 2
Turn it on (at 4 o'clock).

Thus, in this paper feeder, the solenoid! 3 operates as described above, and only while the recording paper passes through the pre-registration switch 6, the high friction pad 4 separates from the paper feed roller 2 in conjunction with the operation of the registration rollers 5.
Frictional resistance between the friction member and paper feed roller 2 is reduced.

Therefore, it is possible to prevent paper dust from being generated from the recording paper that is sandwiched between the paper feed roller 2 and the friction member and sent downstream. Also, when passing thick recording paper with a large coefficient of friction such as overhead project film, the solenoid 13 is pulled in an individual mode to move the high friction pad 4 away from the paper feed roller 4 to reduce frictional resistance. By doing so, you can prevent non-delivery. Furthermore,
It is possible to reduce the wear of the paper feed roller 2 and extend the life of the paper feed roller 2, high friction pad 4, and low friction pad 14.

(F) Effects of the Invention According to the paper feeding device of the present invention, the frictional resistance of the high frictional part of the frictional member is eliminated for a predetermined period of time by the high frictional part separating means, so that the paper feeding roller and the frictional member are It becomes possible to prevent paper dust from being generated from the recording paper sent to the downstream side.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention. That is, FIG. 1 is a diagram illustrating the configuration of the main parts of the paper feeding device seen from the side, FIG. 2 is a diagram illustrating the configuration of the main parts of the paper feeding device seen from the front,
FIG. 3 is an explanatory diagram of the overall configuration of the paper feeding device when the high friction part separating means is not operating, and FIG. 4 is an explanatory diagram of the entire configuration of the paper feeding device when the high friction part separating means is operating. , 5th
The figure is a time chart showing the operation of the high friction part separating means. 3c...First coil spring, 4...High friction pad (high friction part), 5...
...Registration roller, 6...Renost front switch (registration roller actuation means), 7...Inner pad holder, 8...Second coil spring, 9...times Moving shaft, 0...outer pad holder, l...rotating axis, 2...third coil spring, 3... solenoid. j...Paper storage case, 2...Paper feed roller, 3...Paper pressing means, 32L...Bottom plate, 3b...Pushing member, Figure 2 Figure 1 Figure 3 Figure Figure 3

Claims (1)

[Claims] 1. A paper storage case that accommodates a plurality of sheets of recording paper stacked one on top of the other, a paper feed roller, and a paper storage case that presses the top surface of the topmost recording paper in the paper storage case against the paper feed roller. A paper pressing means that feeds out the recording paper by contacting it, a friction member that is biased to press the recording paper to be sent out against the paper feed roller and apply frictional resistance to the lower surface of the recording paper, and a friction member disposed on the downstream side of the paper feed roller. A pair of registration rollers are provided, and a registration roller actuating means is provided on the upstream side near the registration rollers and operates the registration rollers only while the recording paper sent out from the paper feed roller passes. The member is composed of a high friction part and a low friction part having a lower coefficient of friction than the high friction part, the high friction part presses the middle area of the paper feed roller so as to be able to separate it, and the low friction part presses the middle area of the paper feed roller so as to be able to separate from the middle area. The rollers are arranged in the vicinity of the friction member, and are interlocked with the operation of the registration rollers by the registration roller operation means to resist the urging force applied to the high friction portions. A paper feeding device comprising high friction part separating means capable of separating high friction parts.