JPS6214448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a paper feeding device for copying machines, facsimile machines, and the like.

Prior Art As a paper feeding device that feeds stacked sheets, such as paper sheets one by one, there are a roller feeding method that feeds sheets using the rotational force of a roller, a vacuum feeding method that feeds sheets using vacuum pressure, and a paper feeding device. A scraper paper feeding system is already known in which paper is fed by the movement of the oyster's arm. Each of these paper feeding methods has its own advantages, but in order to ensure reliable paper feeding, it is essential that the paper quality and thickness be the same, and that the coefficient of friction between the sheets be uniform. If this condition was not met, double feeds and paper misfeeds occurred frequently.

However, in copying machines, facsimile document feeding devices, etc., there is a need for a paper feeding device that can stack originals of different paper quality, paper thickness, etc. and feed them out one by one. Some people have proposed an air suction paper feeding system. This air suction paper feeding system is configured so that the topmost paper of the stacked sheets is sucked into a suction device, and simultaneously fed by the rotational force of a paper feed roller. Therefore, even if the coefficient of friction between the sheets differs, there is no problem in feeding the sheets, so that sheets of different quality and thickness can be fed. However, when this air suction system has only one paper feed roller, the paper conveying force is insufficient, and it is not only unsuitable for high-speed paper feeding, but also sometimes causes paper failure. In addition, as a countermeasure to solve this problem, a mechanism that uses multiple paper feed rollers may be considered, but in this case, the second sheet is simultaneously sucked at the trailing edge of the first sheet. This sometimes resulted in paper jams.

Purpose The present invention aims to eliminate the drawbacks of the air suction paper feeding method described above and to provide a paper feeding device that can feed sheets reliably and at high speed.

Configuration To achieve this purpose, the present invention includes a detection means for detecting for each paper feed roller that the trailing edge of the sheet to be fed has separated from the paper feed roller, and a detection means that stops the rotational drive of the paper feed roller based on a detection signal. This is achieved by outputting a detection signal from the detection means to the rotational drive stopping means of a paper feed roller whose rear end of the sheet is separated.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is a stacked sheet;
For example, paper sheets 2 are containers for storing paper sheets 1, such as paper cassettes, and above the paper sheets 1, a paper feeding device 3 of an air suction paper feeding type is disposed.

The paper feeding device 3 includes a plurality of paper feeding rollers 4 (three in this example) that are rotationally driven in the direction of the arrow, and a suction mechanism, and this suction mechanism has a large number of air suction holes 5a formed therein. It is composed of an air chamber 5 and a suction means configured as an axial fan 6 installed inside the air chamber 5. The paper feed rollers 4a, 4b, and 4c are arranged in parallel in the paper feed direction A of the paper sheet 1 with appropriate intervals, and rotate forward and reverse in the paper feed direction of the paper feed roller 4 downstream of the paper feed roller 4. A double feed prevention roller pair 7 consisting of rollers is provided.

The paper feeding device 3 according to the present invention has a paper sheet 1 to be fed.
A detection means that detects when the rear end leaves the paper feed rollers 4a, 4b, 4c, and a rotational drive stop that sequentially stops the rotational drive of the paper feed rollers 4a, 4b, 4c based on a signal from the detection means. Means 10a,
10b and 10c are provided.

In this embodiment, the detection means are detectors configured as micro switches 9a, 9b, and 9c for paper detection, which are provided in parallel on the paper transport path 8, and these switches 9a, 9b, and 9c are , are arranged so that the distance between the detection positions is approximately the same length as the distance between the axes of the paper feed rollers 4a, 4b, and 4c. To explain this in an easy-to-understand way, the paper feed rollers 4, a, 4
If the distance between switches _{9a and 9b} is L1, and the distance between switches 9a and 9b is _L1 , and the distance between switches 9a and 9b is L1, and the distance between 4b and 4c is _L1 , and the distance between switches 9a and 9b is
It is arranged so that the distance from c is _l2 . Also, the distance between the switch 9a and the paper feed roller 4a is l ₃
is arranged so as to be approximately equal to the length _l3 of the paper sheet in the paper feeding direction.

The rotational drive stopping means 10a, 10b, 10c
can control the rotation of the paper feed roller 4, and is provided on each of the paper feed rollers 4a, 4b, and 4c. For example, when the paper feed rollers 4a, 4b, 4c are drivingly connected to a drive motor (not shown) via an electromagnetic clutch (not shown), the rotational drive stopping means 10a, 10b, 10c may be used to stop the rotational drive. It outputs a signal to turn on and off the Further, when each of the paper feed rollers 4a, 4b, and 4c is driven by a separate drive motor, a switch is provided to turn on/off the power supply to the motor. The rotation drive stopping means 10a sequentially stops the paper feed rollers 4a, 4b, and 4c based on the detection signal from the switch 9a, the detection signal 10b from the switch 9b, and the detection signal 10c from the switch 9c.

Next, the operating mode of the present invention will be explained.

When a paper feed start signal is issued, the axial fan 6 starts rotating in response to this signal, and the uppermost paper of the paper sheets 1 placed thereon is sucked into the air chamber 5.
At the same time as this suction, the paper feed rollers 4a, 4b, and 4c start rotating, and the sucked paper sheet 1 is sent in the direction of arrow A, and the leading edge of the paper sheet 1 eventually passes the double-feed prevention roller pair 7. and sent into the conveyance path 8. Then, the tip of the fed paper sheet 1 is connected to the switch 9a.
When detected, a detection signal from the switch 9a is output to the rotation drive stop means 10a, and the paper feed roller 4a is
Stops rotational drive. Further, the leading edge of the paper sheet 1 is sequentially detected by the switches 9b and 9c, and the rotational drive of the paper feed rollers 4b and 4c is sequentially stopped in the same manner as described above. Thereafter, the sent paper sheet 1 is held between a pair of transport rollers (not shown) and sent into the main body of a copying machine or the like to be fed.

In this case, the axial fan 6 operates until the trailing edge of the sheet 1 leaves the sheet feed section. Therefore, the next highest sheet 1 may be sucked into the air chamber 5 before the sheet 1 to be fed leaves the sheet feeding section. However, in the paper feeding device of the present invention, when the paper sheet 1 to be fed is detected by the switch 9a, the paper feeding roller 4a stops;
Since the length _l3 in the feeding direction is equal to the distance _l3 from the paper feed roller 4a to the switch 9a, even if the next sheet 1
Paper feed roller 4 with which the paper comes into contact even if a is sucked
This means that a has already stopped. When the next sheet of paper is detected by the switches 9b and 9c in order to be fed while the next sheet of paper is being sucked, even when the next sheet of paper comes into contact with the paper feed rollers 4b and 4c, the paper has already been fed. The rollers 4b and 4c are also stopped. Therefore, when the second paper sheet is sucked, all the paper feed rollers 4 are stopped, and the paper feed rollers 4 are not fed and a paper jam does not occur. Additionally, regarding the conventional air suction type paper feeding device equipped with multiple paper feeding rollers, conventionally all of the paper feeding rollers were rotated and stopped at the same time, as shown in the figure. When the next paper sheet 1a is sucked, it is sent out by the rotation of the paper feed roller 4a, and the double feed prevention roller pair 7
Advancement is blocked by the lower reversing roller. However, there is a problem in that the paper sheet 1a is forcibly stopped and the feeding operation continues, resulting in a paper jam. It's as obvious as this. Furthermore, conventionally, it has been proposed to stop all of the paper feed rollers 4 at the point when the paper sheet to be fed is bitten by the double-feed prevention roller. If paper is conveyed only by rollers with feeding power, not only will paper not be fed due to the frictional load of the paper feed roller that has stopped rotating, but it will also be pointless to install multiple paper feed rollers for high-speed conveyance. .

According to the above configuration, even if a plurality of paper feed rollers are provided, it is possible to prevent paper jams as in the conventional case, and furthermore, since the paper feed roller is rotated until the paper is separated to be fed, the conveyance force of the paper feed roller is reduced. By making full use of it, high-speed paper feeding became possible.

By the way, it is conceivable that the paper feeding device of the present invention may have a problem in feeding sheets of paper having different lengths in the feeding direction. In this case, switches 9a, 9b, 9c
may be provided on one moving member (not shown), and the position of this moving member may be adjusted depending on the size of the paper sheet. That is, if the paper cassette is, for example, number 5 in row B, then the distance between the paper feed roller 4a and the switch 9a is set to B.
Adjust the moving member so that it is equal to the length in the feed direction of row No. 5, and if it is row A no. 4, adjust it again. Note that this adjustment can be performed by providing a detection device and a drive device, and activating the drive device in response to a signal from the detection device to automatically adjust and move the moving member, or manually.

FIG. 2 shows another embodiment of the present invention,
In this embodiment, the detection means consists of one microswitch 9a and a timer 11. In this case, the switch 9a is arranged to have a width _l3 in the feeding direction of the paper sheet 1 from the paper feed roller 4a as in the above embodiment, and the signal from the switch 9a is transmitted to the timer 11.
A signal is output to the rotation stop means 10a. Also, the timer 11 is set to switch 9a.
From the signal of
rotation stop means 10b, 10, respectively when passing through
The timer includes, for example, a cam (not shown) and a microswitch (not shown) operated by the cam. Note that the other configurations are the same as in the above embodiment.

The paper feeding device configured in this manner is capable of feeding paper sheets 1 to be fed.
When the rear end leaves the paper feed roller 4a, the switch 9a detects the leading end. Then, the detection signal is output to the rotation stop means 10a and the timer 11, and the timer 11 detects that the paper sheet 1 is
The rotation stop means 10 is almost synchronized with the time of leaving c.
Signals are output to b and 10c, respectively. Therefore, the same effects as in the above embodiment can be obtained in this embodiment as well.

Effects The paper feeding device according to the present invention is configured as described above, and it has become possible to feed paper sheets of different quality and thickness reliably and at high speed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of a paper feeding device according to the present invention, and FIG. 2 is a sectional view showing another embodiment thereof. 1...Paper leaf, 3...Paper feeder, 4a, 4b, 4c...
Paper feed roller, 5... Air chamber, 6... Suction means, 9a, 9b, 9c... Micro switch, 10
a, 10b, 10c... Rotation stop means, 11... Timer.

Claims (1)

[Scope of Claims] 1. A plurality of paper feed rollers 4a, 4b, and 4c arranged in parallel in the sheet feeding direction above the stacked sheets; In a paper feeding device that has suction mechanisms 5 and 6 that suction in tangential directions, and feeds the sheet sucked by the suction mechanism by rotation of the paper feed roller, the sheet is fed. Detection means 9 for each paper feed roller to detect that the trailing edge of the sheet has left the paper feed roller
a, 9b, 9c, 11, and rotational drive stop means 10a, 10b, 10c, which are provided on each of the paper feed rollers and stop the rotational drive of the paper feed rollers in response to a detection signal from the detection means, The paper feeding device, wherein a detection signal from the detection unit is output to the rotational drive stopping unit of the paper feeding roller whose rear end of the sheet is separated. 2. The detection means includes the same number of detectors 9a, 9b, and 9c as the number of paper feed rollers, which are arranged downstream of the paper feed roller in the sheet feed direction and spaced apart from each paper feed roller by a sheet width in the feed direction. , a paper feeding device according to claim 1. 3. Claim 1, wherein the detection means is composed of one detector 9a and a timer 11.
Paper feeding device as described in section.