JPH02209352A - Sheet feeder - Google Patents

Abstract

PURPOSE:To secure a sheet feeder installed in a various machines capable of performing sheet insertion and its tilt correction in an easy manner by installing a transfer means, selecting a wave being formed in an elastic body to progressive wave or standing wave, and also a control means changing this transfer means over to the progressive wave formation side. CONSTITUTION:Sheet insertion is detected by a set of a light emitting element 10a and a light receiving element 10c set up in a sheet inserting port whereby a controller CNT opens switches 8a, 8b, forming a standing wave in each of elastic bodies 5, 6. When these switches 8a, 8b are opened, electric energy produced in vibrators 2, 4 is not dissipated in an energy absorbing part 9, and vibration is reflected, thus the standing wave is formed. When this standing wave is formed in these elastic bodies 5, 6, frictional resistance between a sheet and the elastic bodies becomes very small, and since conveying force in the feeding direction is approximated to almost zero, the sheet is easily inserted and its tilt can be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a sheet feeding device installed in a computer, a copying machine, a facsimile machine, a word processor, a typewriter, and other various machines equipped with a mechanism for feeding sheets. be.

(Background of the Invention) Conventionally, this type of device has been configured to feed the sheet by forming a traveling wave in an elastic body that clamps the sheet, as disclosed in Japanese Patent Laid-Open No. 59-177243. Ta.

Here, we will discuss the second principle of sheet conveyance in the above proposal.
This will be explained using figures.

The sheet 13 is held between the elastic bodies 11 and 12 with appropriate pressure. Progressive bending vibrations (progressive waves) are formed in each of the elastic bodies 11 and 12, and the phase difference between these progressive waves is spatially 180°. The bending vibration of .12 progresses on the sheet 13 side so that each convex portion always faces each other. At this time, if attention is paid to, for example, a mass point with a convex portion on the surface of the elastic body 11, 12, the mass point generally moves in an elliptical orbit. In FIG. 2, regarding the elastic body 11, when the traveling wave moves to the right, the mass point will draw a clockwise elliptical locus as shown in the figure. Therefore, the moving direction of the mass points of the convex portions of the elastic bodies 11 and 12 is opposite to the direction of vibration, and this acts as a force to transport the sheet 13.

On the other hand, in the concave portion, a sheet transporting force is generated in the same direction as the traveling direction, but the pressure is smaller than that in the convex portion, so the frictional force between the sheet 13 and the elastic body 11, 12 is small, and the sheet transporting force is also small. Therefore, the total sheet conveying force acts in the direction opposite to the direction in which the bending vibrations described above proceed.

FIG. 3 shows an example of a device that generates the sheet conveying force as described above, and in the figure, reference numerals 11, 12 and 13 are the aforementioned elastic bodies and sheets. Also, 14-1. 14-2
．． 15-1 (not shown) and 15-2 are the elastic bodies 11.1
A vibrator fixed on 2, 16 a pressing support member, 17-
1. 17-2 is a support side plate, and 18 is a bottom plate.

The elastic body 12 is supported by a bottom plate 18, and the elastic body 11 is supported by a pressing support member 16.

Further, the elastic body 11 presses the sheet 13 with an appropriate force due to the spring property of the suppressing support member 13, and holds the sheet 13 together with the elastic body 12.
By applying a certain frequency voltage to each vibrator 12 and applying vibration, the respective convex portions are always facing each other as described above, so that a sheet conveying force is generated.
The sheet is conveyed in the direction of the arrow in the figure. Note that the arrows in the figure point in both directions, which means that the direction of sheet conveyance can be reversed by switching the direction of vibration.

FIG. 4 and FIG. 5 show an example of a device (only the main parts are shown) in which the vibrating body is realized with a different configuration.

FIG. 4 shows a track-shaped vibrator 19-1. Similarly track-shaped elastic body 20-1.20-2 to which 19-2 is fixed
The structure is such that the sheet 13 is held between the vibrator 19-
1. By applying a frequency voltage to 19-2, elastic body 20-1
．． By forming progressive bending vibration in 20-2,
The point of generating the sheet conveying force is similar to the apparatus shown in FIG. 3 above.

FIG. 5 is a cross-sectional view of the apparatus shown in FIG. 4 as viewed from the sheet feeding direction, and there is a difference in level between the left and right sides. This is the elastic body 20-
1. Since the direction of the sheet transport force is acting in opposite directions on the left and right sides of 20-2, this is to prevent the transport force on the opposite side (the right side in Figure 5) from acting on the sheet 13. be.

By the way, in the conventional device as described above, when inserting a sheet, traveling waves are formed in the elastic body.
A transporting force acts on the sheet while it is being inserted, and if the sheet is inserted at an angle, the sheet will be conveyed at an angle.

Further, in order to avoid this, it is conceivable to perform traveling wave driving only after the insertion of the sheet is completed, but in this case, the frictional resistance against the sheet is high and it is difficult to insert the sheet.

(Object of the Invention) An object of the present invention is to solve the above-mentioned problems and provide a sheet feeding device that can easily insert a sheet and correct the inclination of the sheet.

(Features of the Invention) In order to achieve the above object, the present invention provides a switching means for changing the wave formed on the elastic body into a traveling wave or a standing wave, and a first detection means for detecting when a sheet is inserted. , a second detection means detects the completion of sheet insertion, and upon detection by the first detection means, the switching means switches to the standing wave forming side. In order to convey the sheet by applying a conveying force to the pressed sheet, a control means for switching the switching means to the traveling wave forming side is provided, so that when the sheet is inserted, a standing wave is formed and the conveying force is It is characterized by reducing only frictional resistance without working.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, 1.2,
3.4 is a vibrator made of a piezoelectric element, 5゜6 is an elastic body, 7
8a is an oscillator that applies a frequency voltage to the vibrators 1 to 4;
, 8b is a switch, 9 is an energy absorption part, 10a, 1
Reference numeral 0b denotes a light projecting element, which together with light receiving elements 10c and 10d constitutes means for detecting that the sheet has arrived at the insertion slot or a predetermined position. CNT is a controller.

The vibrator 1.2 is fixed to the elastic body 5 with adhesive or the like.

Similarly, the vibrator 3.4 is fixed to the elastic body 6 with adhesive or the like. Further, the elastic bodies 5 and 6 are held down with an appropriate force. In this embodiment, the elastic bodies 5 and 6 are connected to a ground circuit as conductors, and vibration is generated in the elastic bodies 5 and 6 by applying a frequency voltage (alternating current electric field) to the vibrator 1 by an oscillator 7. do. The vibrators 2 and 4 generate electricity as the elastic bodies 5 and 6 vibrate. When the switches 8a, 8b are closed, the generated electrical energy is dissipated by the energy absorbing section 9 made of a resistor or the like. Therefore, in this case, the vibration becomes a traveling wave without being reflected. Elastic body 5
, 6 becomes a traveling wave, and if we focus on one point on its surface, its locus depicts an ellipse. Therefore, the outside part of the bend always has a velocity component in the opposite direction to the traveling direction of the traveling wave, and since the sheet is always in contact with the part outside the bend, it has a velocity component in the opposite direction to the traveling direction of the traveling wave. Sent. In FIG. 1, sheets are fed from left to right.

Next, the case of inserting a sheet will be explained.

As mentioned above, when a sheet is inserted with a traveling wave formed in the elastic body in advance, a transporting force acts on the sheet, so
If the sheet is tilted, it will be conveyed in that state. Alternatively, in order to avoid this, it is possible to form a traveling wave on the elastic body and start conveyance after the sheet is inserted, but in this case, there is a large frictional resistance between the sheet and the elastic body. insertion is extremely difficult.

Therefore, in the device of this embodiment, whether or not a sheet has been inserted is detected by the pair of light emitting element 10a and light receiving element 10c arranged in the sheet insertion slot, that is, by the on/off state of the light receiving element 10c (the controller CNT detects this by checking the on/off state of the light receiving element 10c). make judgments) and
Upon detecting that the sheet has been inserted, the controller CNT opens the switches 8a and 8b to close the elastic bodies 5.
6 to form a standing wave. In this way, switches 8a and 8b
When the oscillator 2.4 is opened, the electrical energy generated by the vibrator 2.4 is not dissipated in the energy absorbing section 9, and therefore the vibration is reflected and a standing wave is formed. When standing waves are formed in the elastic body 5.6, the frictional resistance between the sheet and the elastic body becomes very small, and the conveying force in the feeding direction becomes almost zero, making it easy to insert the sheet. becomes possible. Furthermore, even in the inserted state, there is almost no frictional resistance, so the sear can be easily moved. Therefore, even if the sheet is tilted, the tilt can be easily corrected.

Next, when the sheet insertion is completed, the controller CNT closes the switches 8a and 8b, but whether or not the sheet insertion is completed is determined based on the on/off states of the light emitting element 10b and the light receiving element 10d. The switches 8a, 8b
When closed, as mentioned above, the electrical energy generated in the vibrator 2.4 is dissipated and the vibration is no longer reflected.
A traveling wave is formed in the elastic body 5.6, and the conveyance of the sheet begins.

According to this embodiment, since standing waves are formed when inserting the sheet, it is possible to easily insert the sheet and correct the inclination of the sheet.

(Correspondence between the invention and the embodiment) In this embodiment, the oscillator 7 is the waveforming means of the present invention.
The light emitting element 10a and the light receiving element 10c serve as first detection means,
The light emitting element 10b and the light receiving element 10d serve as second detection means,
The switches 8a, 8b and the energy absorbing section 9 correspond to switching means, and the controller CNT corresponds to control means.

(Modification) In this embodiment, the determination of sheet insertion completion is made using the light emitting element 10.
Although the determination is made based on the on/off state of the light receiving element 10c and the light receiving element 10d, it may also be determined based on, for example, that the off state continues for a predetermined period of time after the light receiving element 10c is turned from on to off.

(Effects of the Invention) As explained above, according to the present invention, the switching means for changing the wave formed on the elastic body into a traveling wave or a standing wave, and the first detection means for detecting when a sheet is inserted. , the switching means is switched to the standing wave forming side by the detection by the second detection means for detecting the completion of sheet insertion and the first detection means, and the detection by the second detection means causes the elastic body surface to In order to convey the sheet by applying a conveying force to the pressed sheet, a control means for switching the switching means to the traveling wave forming side is provided, so that when the sheet is inserted, a standing wave is formed and the conveying force is Since only the frictional resistance is reduced without working, it is possible to easily insert the sheet and correct the inclination of the sheet.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a diagram for explaining a sheet conveying system in this type of device,
FIG. 3 is a perspective view showing the structure of a conventional device, FIG. 4 is a perspective view showing the structure of another conventional device, and FIG. 5 is a sectional view taken from the sheet feeding direction of FIG. 1.2.3.4... Vibrator, 5.6...
・Elastic body, 7... Oscillator, 8a, 8b...
...Switch, 9...Energy absorption section, 10
a, 10b... Light projecting element, 10c, 10d...
... Light receiving element, CNT ... Controller.

Claims (1)

[Claims] (1) In a sheet feeding device comprising an elastic body to which a vibrator is fixed, and a wave forming means that applies a frequency voltage to the vibrator to form waves on the elastic body, A switching means for changing the wave to a traveling wave or a standing wave, a first detecting means for detecting when the sheet is inserted, a second detecting means for detecting the completion of sheet insertion, and detection by the first detecting means. , the switching means is switched to the standing wave forming side, and the switching means is switched to the traveling wave forming side in order to transfer the sheet by applying a transporting force to the sheet pressed against the elastic body surface by detection by the second detection means. A sheet feeding device characterized by comprising a control means for switching to a forming side.