JPH03152037A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent the generation of sheet powder from a recording sheet fed to the downstream side in a state to be nipped between a feed roller and a friction member by providing a means to relieve the magnitude of frictional resistance of a friction member against an energizing force exerted on the friction member in linkage with operation of a resist roller during operation of the roller. CONSTITUTION:A frictional resistance relieving means formed with a coupling plate 10, a third coil spring 12, and a solenoid 13 is operated to relieve the magnitude of frictional resistance of a friction pad 4 in linkage with operation of resist rollers 5 and 5 only during the passage of a recording sheet through a resist front switch 6. This constitution prevents the generation of sheet powder from a recording sheet fed to the downstream side in a state to be nipped between a feed roller 2 and a friction pad 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a paper feeding device, and more specifically, to an image forming device such as a photo-reading machine or a facsimile. This is a description of the paper feeding device that supplies paper to the transfer unit in units of ti.

(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 paper feeding device, the friction member is always pressed against the paper feeding roller with the same pressure during paper feeding.

(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 it one sheet at a time 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 paper dust during paper feeding and eliminate the above-mentioned adverse effects.

(d) Means for Solving the Problems and Their Effects This invention includes a paper storage case for storing record sheets of defeat and defeat cards in a stacked manner, a paper feed roller, and the paper feed roller located at the top of the paper storage case. a paper pressing means that presses the upper surface of the upper recording paper into contact and sends out the recording paper; and a friction member that is biased to press the delivered recording paper against a paper feed roller and apply frictional resistance to the lower surface of the recording paper. , a pair of registration rollers disposed downstream of the paper feed roller, and a pair of registration rollers disposed upstream near this registration roller that operate the registration rollers only while the recording paper is being fed out from the paper feed roller. and a registration roller actuation means, which is further disposed near the friction member, and is interlocked with the operation of the registration roller when the registration roller actuation means operates the registration roller, so that the friction member resists the retainer biasing force and increases the friction of the friction member. This paper feeding device is equipped with frictional resistance alleviating means for alleviating the magnitude of resistance.

That is, the paper feeding device of the present invention is characterized in that a friction alleviation means, which was not available in the past, is provided near the friction member. The friction reducing means attempts to reduce the magnitude of the frictional resistance of the friction member in conjunction with the operation of the registration rollers only while the recording paper passes through the registration roller operating means.

Thus, in this paper feeding device, the frictional resistance of the frictional member is reduced for a predetermined period of time by the frictional reducing means.Secondly, the recording paper that is sandwiched between the paper feeding roller and the frictional member and sent to the downstream side This makes it possible to prevent paper dust from being generated.

(e) Example Hereinafter, the present invention will be described in detail based on one practical example shown in the figure. Note that this invention is not limited to this.

In FIGS. 1 to 3, the paper feed device P includes a paper storage case 11, a paper feed roller 2, a paper pressing means 3, a rubber friction pad 4 as a friction member, a pair of registration rollers 5, and a registration roller operating means. A pre-registration switch 6 is provided.

A paper storage case is used to store a large number of recording sheets stacked one on top of the other. The paper feed roller 2 has the role of feeding out the recording paper by rotating while contacting the upper surface of the recording paper stored therein. The paper suppressing means 3 includes a paper storage case on the paper feed roller 2! Press the recording paper inside to avoid contact.

This paper pressing means 3 is a bottom plate 3a inside the paper storage case l.
It consists of a push-up member 3b that pushes up the bottom plate 3a, and a first coil spring 3c that always urges the push-up member 3b upward.

The friction pad 4 is attached to the upper end of the pad holder 7. The pad holder 7 is supported by a rotating shaft 9 at an intermediate portion. Further, a second coil spring 8 is attached to the lower end of the pad holder 7 as a biasing means. The friction pad 4 is then moved to the pad holder 7 by the second coil spring 8.
is urged toward the upper right through the paper feed roller 2, and is pressed against the paper feed roller 2.

A connecting plate 10 supported by a rotating shaft 11 is disposed below the pad holder 7 . The pad holder 7 and the connecting plate lO are connected by a third coil spring 12. The right end portion of the connecting plate 10 is rotatably attached to the operating portion of the solenoid 13. The connecting plate lO1, the third coil spring 12, and the solenoid 13 are combined to constitute a frictional resistance alleviating means. In other words, the frictional resistance alleviating means acts to reduce the amount of frictional resistance of the friction bed 4 in conjunction with the operation of the rollers 5, 5 only while the recording paper passes through the pre-registration switch 6.

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

In FIGS. 2 and 4, when the first sheet feed signal is input and the paper feed roller 2 turns 'ON L' and its rotating shaft rotates, the paper feed roller 2 picks up the recording paper in the paper storage case l. This recording paper is combined into one sheet at the nip portion with the friction ped 4 and sent toward the registration roller pair 5.5.

When the leading edge of the recording paper reaches the pre-registration switch 6, the switch 6 is turned on (1+ time).

Then, align the leading edge of the paper by bringing the leading edge of the paper into contact with the registration roller pair 5. When the leading edge of the recording paper is aligned, the drive of the paper feed roller 2 is turned off (at the time of IT). At this time, the 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 third coil spring 12 via the connecting plate IO, as shown in FIG. Then, the third coil spring 1
2 pulls the pad holder 7 downward to relieve the nip pressure.

Thereafter, the pair of registration rollers 5 transports the recording paper to the next process. During this time, the paper feed roller 2 is driven by the recording paper by holding a one-way clutch on its rotating shaft.

With the nip pressure relaxed, the registration roller pair 5. 5 stops rotating, and at the same time solenoid 13h<OFF (at 1+). After that, the second sheet feed signal is input and paper feed roller 2 is turned on (1. o'clock)
.

Thus, in this paper feeding device, the connecting plate lO1 third
The frictional resistance reducing means consisting of the coil spring 12 and the solenoid 13 operates as described above, and the registration roller 5 is operated only while the recording paper passes through the pre-registration switch 6.
- In conjunction with the operation of 5, the magnitude of the frictional resistance of the friction pad 4 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 pad 4 and sent to the downstream side. Furthermore, when passing thick recording paper with a large coefficient of friction such as film for overhead projects, non-feeding can be prevented by pulling the solenoid 13 in side splitting mode to reduce frictional resistance.

Furthermore, it is possible to reduce the wear of the paper feed roller 2 and extend the life of the paper feed roller 2 and the friction pad 4.

(F) Effects of the Invention According to the paper feeding device of the present invention, the frictional reducing means reduces the amount of frictional resistance of the frictional member for a predetermined period of time. This makes it possible to prevent the generation of paper dust from the recording paper that is sent to the printer.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention. That is, FIG. 1 is an explanatory diagram of the main part configuration of the paper feeding device, FIG. 2 is an explanatory diagram of the overall configuration of the paper feeding device when the frictional resistance reducing means is not operating, and FIG. FIG. 4 is a time chart showing the operation of the frictional resistance reducing means.

[...Paper storage case, 2...Paper feed roller, 3...Paper pressing means, 3a...Bottom plate, 3b...Pushing up Member, 3c...First coil spring, 4...Friction pad (friction 1% [member), 5...
...Registration roller, 6...Registration front switch (registration roller operation child), 7...Pad holder, 8...Second coil spring, 9... Rotating shaft, lO...Connecting plate,
l[...Rotating wheel, Supervisor 2...Third coil spring, 13...Solenoid. ] Figure Figure Figure

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 provided therein; and a registration roller actuating means that is provided upstream near the registration rollers and operates the registration rollers only while the recording paper sent out from the paper feed roller passes; , a frictional resistor disposed near the frictional member, which is interlocked with the operation of the registration roller when the registration roller operating means operates the frictional member, and is capable of alleviating the magnitude of the frictional resistance of the frictional member against the urging force applied to the frictional member. A paper feeding device comprising a relaxation means.