JPS60197544A - Paper supply device - Google Patents

Abstract

PURPOSE:To make it possible to surely prevent two overlapping sheets from being fed, by providing such an arrangement that a normally rotating roller is rotated in the paper feed direction under operation of a one-way clutch even upon a drive source for the roller being rested. CONSTITUTION:When the leading end of a paper 3 reaches a feed roller 8, a sensor 14 detects this leading end so that a step motor 9 for driving a normlly rotating roller 1 is rested in association with the output of the sensor 14. The paper 3 is continuously fed by the feed roller 8, and at this time, since a one way-clutch is applied with torque in its sliding direction, the normally rotating roller 1 may be rotated in association with the advance of the paper 3 even if the step motor 9 is rested. When the paper 3 has completely passed through the pressing section between the normally rotating roller 1 and a reverse roller 2, the normally rotating roller stops its rotation, thereby papers subsequent to the second one may be sustained in a stand-by condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (al) Technical Field of the Invention The present invention relates to a paper feeding device, and more particularly to a paper feeding device that can reliably feed one sheet of paper at a time without having to feed two sheets of paper.

(bl) Prior Art and Problems Conventionally, there are anti-rubbing plate methods, Konatsume methods, etc. as methods for preventing double sheet feeding in paper feeders, but both have problems in reliability and high-speed adaptability.

The present invention relates to an improvement of the double-sheet feeding prevention system using a reversing roller system (Japanese Patent Laid-Open No. 57-98445), which was previously filed. Fig. 1 shows a principle diagram of preventing double-sheet feeding using the conventional reversing roller system. .

In the figure, l is the 10th roller that always rotates in a predetermined direction (hereinafter referred to as the normal rotation roller), and 2 is the second roller that is driven in the opposite direction via a torque limiter (hereinafter referred to as the reverse rotation roller). do).

3 is the upper paper to be sent out, 4 is the lower paper to be kept on standby, arrow F is a predetermined paper feeding direction (hereinafter referred to as the F direction), and arrow B is the opposite direction to the F direction (hereinafter referred to as the B direction). shows.

When two sheets of paper are fed between these two rollers, the friction coefficient between the sheets is relatively small at 0.3 to 0.5, so the drive torque of the reversing roller 2 overcomes the friction coefficient between the sheets, and the paper 4 Return to direction B. The paper 3 is transferred to F by the forward rotating roller 1.
sent in the direction.

Also, when a sheet of paper 3 is fed between both rollers, the friction coefficient between the paper and the rollers is as large as 1.2 to 1.4, so the paper 3 is moved in the F direction by the normal roller, and the paper 3 is As the rotation roller 3 moves, a torque limiter (not shown) operates, and the reverse rotation roller 2 is driven to rotate in the F direction.

FIG. 2 shows a diagram for explaining the drawbacks of the conventional reversing roller system.

In the figure, immediately after the paper 3 passes through the pressure contact area between the forward rotation roller 1 and the reverse rotation roller 2, the reverse rotation roller 2 starts to follow rotation in the F direction by the forward rotation roller 1, and the paper 4 that has been waiting until then is removed. I will continue to send it. For this reason, there was a problem in that the spacing between sheets could not be maintained properly. To solve this problem, conventionally a method has been adopted in which the reverse rotation roller 2 is separated from the normal rotation roller 1 before the paper 3 passes through both rollers. However, if the reversing roller 2 is separated, the ability to separate the paper will be lost, so a stopper is provided that presses down the paper 4 from above to prevent the paper 4 from moving forward.
It had the disadvantage of being mechanically complex.

(C) Object of the Invention In view of the above-mentioned conventional drawbacks, the present invention aims to provide a paper feeding device that can reliably prevent double sheet feeding.

(d) Structure of the Invention According to the present invention, the first roller and the second roller driven by a constant torque are brought into pressure contact with each other and driven to rotate, thereby preventing the feeding of two sheets of paper. In the paper feeding device, the first roller is driven via a one-way clutch, and the sheet paper being fed is fed to a predetermined length by driving the first roller and the second roller. This is achieved by providing a paper feeding device characterized in that the rotation of the first roller is stopped upon detecting that the first roller is rotated.

+81 Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

In the top view, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 3 is a side view showing an embodiment of the paper feeding device according to the present invention, and FIG. 4 is an explanatory diagram of the operation of FIG.
), each part is explained in order according to the position where the paper is sent out.

Fig. 3 shows a side view of an example applied to a reading mechanism used in a facsimile machine, etc., and roughly divided into ■ is the document transport mechanism, and ■ is the reading optical system (including the reading unit illumination light). ) is shown.

The document transport mechanism section I includes a document table 5. Manuscript paper 6 stacked on the manuscript table 5 (the highest paper is distinguished from paper 32 and the next highest paper is paper 4), a feeding roller 7 that feeds out the manuscript paper 6 one by one according to a command, and the first paper fed out. A drive source (hereinafter abbreviated as a step motor) 9 is provided which presses the motor 3 between the normal rotation roller 1 and the reverse rotation roller 2 and causes the motor to travel in the F direction.

The step motor 9 also commonly drives the feed roller 7 in the F direction at the same time. A one-way clutch 12 whose meshing direction is in the F direction is interposed between the step motor 9 and the normal rotation roller 1.

The reversing roller 2 is connected to a constant torque drive source (hereinafter abbreviated as DC motor) 10 and rotates in the B direction.

This DC motor IO is driven with a constant current so as to output a constant torque. Therefore, if the load applied to the DC motor 10 is within the constant torque limit, the reversing roller 2 is
When the limit is exceeded, it rotates in the F direction.

Driving the DC motor 1o with a constant current has the same function as a conventional torque limiter.

Reference numeral 8 denotes a delivery roller, which consists of a pair of upper and lower rollers;
It is rotated in the F direction by a step motor 11.

The distance between the pressure contact point between the normal rotation roller 1 and the reverse rotation roller 2 and the pressure contact point of the delivery roller 8 is set to be slightly shorter than the length of the paper 3 in the feeding direction. Reference numerals 13 and 14 indicate sensors that detect the position of the leading edge of each paper being sent out.

The operation of FIG. 3 will be explained below with reference to FIG. 4.

FIG. 4 Ta) shows the standby state before operation. In this state, the step motor 9 is stopped. When a paper feed command is given, the step motor 9 rotates and the feed roller 7
rotates in the F direction. Next, by a descending function (not shown), as shown in FIG. 4 (bl), the feeding roller 7 descends and presses onto the paper 6 stacked on the document table 5, and feeds out the topmost paper 3 in the direction F. Next, as shown in FIG. 4(C), when the leading edge of the paper 3 reaches the normal rotation roller 1, the sensor 13 detects this, and the feed roller 7 moves upward based on the detection signal.At the same time, the step motor 9 The forward rotation roller 1 is rotated in the F direction via the one-way clutch 12, and the paper 3 is sent to the delivery roller 8.At this time, the forward rotation of the second and subsequent sheets is prevented by the reverse rotation roller 2.

Next, as shown in FIG. 4 (dl), when the leading edge of the paper 3 reaches the delivery roller 8, the sensor 14 detects this, and the step motor 9 is stopped based on the output of the sensor 14.

The paper 3 is continuously fed by the feed roller 8, and at this time, the one-way clutch I2 is given rotational force in the sliding direction.
The normal rotation roller 1 can be driven to rotate as the paper 3 moves forward even when the step motor 9 is stopped. Next, as shown in FIG. 4 (el), when the paper 3 finishes passing through the pressure contact area between the forward rotation roller 1 and the reverse rotation roller 2, the normal rotation roller 1 stops its driven rotation. Paper 6 remains in a standby state.

(f) Effects of the Invention As explained in detail above, according to the paper feeding device of the present invention, even if the drive source for the normal rotation roller is stopped, the normal rotation roller is driven in the predetermined paper feeding direction by the action of the one-way clutch. It is possible to rotate the paper, and the normal rotation roller drive can be stopped while the paper is passing between the rollers, so that the next paper is not continuously fed, and an appropriate paper interval can be maintained.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of preventing double sheet feeding using a conventional reversing roller system, Fig. 2 is a diagram for explaining the drawbacks of the conventional reversing roller system, and Fig. 3 is an embodiment of a paper feeding device according to the present invention. FIG. 4 is a side view showing the operation of FIG. 3. In the figure, 1 is the first roller, 2 is the 20th roller, 3 is the top paper, 4 is the next paper, 6 is the stacked paper,
9 is a drive source, and 10 is a constant torque drive source. 12 indicates a one-way clutch.

Claims (1)

[Claims] In a paper feeding device equipped with a mechanism that prevents feeding of two sheets of paper by pressing a first roller and a second roller driven by a constant torque and driving the rotation, the first roller is It is driven via a one-way clutch, and detects that the sheet paper being fed out has been sent out to a predetermined length by driving the first roller and the second roller, and then controls the rotation of the first roller. A paper feeding device characterized in that it is configured to stop.