JPH0331139A - Sheet feeder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] 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. It is something.

[Prior art] This type of device was previously developed in Japanese Patent Application Laid-open No. 5! As disclosed in Japanese Patent No. 1-177243, a traveling wave is formed in an elastic body that clamps a sheet to feed the sheet.

Here, we will discuss the third 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 1110''. The bending vibration of .12 progresses in such a way that each convex part always faces the sheet 13 side.At this time, if we pay attention to a mass point on the surface of the elastic body 11, 12, for example in the image area, the mass point is generally The elastic body 11 moves in an elliptical orbit.
In other words, when the traveling wave moves to the right, the mass point will draw a clockwise elliptical trajectory as shown in the figure. Therefore, the movement direction of the mass point of the convex portion is the elastic body 11.
12, the direction is opposite to the direction of vibration, and this acts as a force to feed the sheet 13 eight times.

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 1112 is small, and the sheet transporting force is also small. The total sheet transport force is:
The bending vibration acts in the opposite direction to the direction of movement of the bending vibration described above.

FIG. 4 shows an example of a device that generates the sheet transport force as described above, and FIG. 5 is a cross-sectional view of the device shown in FIG. 4 taken along a plane perpendicular to the sheet feeding direction. It is.

In FIG. 4, forming a traveling wave in the elastic bodies 20-1 and 20-2 and generating a transporting force on the sheet is similar to that shown in FIG. 20-
Since 2 has a track shape, the directions of the traveling waves generated on the opposing straight parts of the elastic body are different, so the direction of the transport force applied to the pressed sheet is different.
It was difficult to obtain transfer force in a fixed direction. In order to solve this difficulty, conventionally, as shown in FIG. 5, a step was provided on the surface of the elastic body so that the elastic body was pressed only by one straight section.

[Problems to be Solved by the Invention] In the conventional example, since the elastic body is provided with a step, the stiffness of the elastic body becomes partially non-uniform, resulting in non-uniform traveling wave amplitude or torsional vibration amplitude. This method has disadvantages in that the sheet conveyance speed decreases or sheet conveyance speed fluctuations increase due to an increase in the number of sheets.

An object of the present invention is to provide a sheet feeding device that can maintain sheet conveyance with high precision without providing a step in an elastic body.

[Means for Solving the Problems] The gist of the present invention is to achieve the object of the present invention by using electric-mechanical energy conversion elements that are excited to generate progressive vibrations and are arranged opposite to each other. In a sheet feeding device that has a pair of elastic bodies and conveys a sheet by applying a conveying force to the sheet held between the elastic bodies, the
The pair of elastic bodies are formed symmetrically with respect to the sheet conveying direction, with sheet conveying surfaces formed in opposite directions of the sheet conveying force, and one of the pair of elastic bodies presses the sheet on the sheet conveying surface side. There is a sheet feeding device characterized in that both elastic bodies are held at an angle with respect to a sheet transfer path so as to form a gap on the other sheet transfer surface side.

[Function] The sheet feeding device configured as described above presses and pinches the sheet on one sheet transfer surface side of the pair of elastic bodies that are different in the sheet transfer direction, and does not press and pinch the sheet on the other sheet transfer surface side. , only the sheet transport force generated on one sheet transport surface side is applied to the sheet.

[Embodiment] FIG. 1 is a schematic diagram showing an embodiment of a sheet feeding device according to the present invention.

This embodiment includes track-shaped elastic bodies 20-120-2 to which track-shaped vibrators 19-1 and 19-2 are fixed.
The structure is such that the sheet 13 is held between the vibrator 19-
1.19-2 by applying a frequency voltage to the elastic body 20-1.
A progressive bending vibration is formed at 20-2.

When bending vibration becomes a traveling wave, if we focus on one point on its surface, its locus draws an ellipse as described above. 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.

FIG. 2 is a sectional view taken along the line A-A in FIG.
1.20-2 is a straight part 2 in the other direction so as to press against the sheet 13 at the side edge of one straight part 2O-1a, 2O-2a.
O-1b and 2O-2b are arranged at an angle with respect to the sheet conveyance surface so as to be open. That is, within the straight portion, the direction of the traveling wave is in a constant direction, so that a transporting force in a constant direction can be obtained.

Also, since there is no need to provide a step shape on the surface of the elastic body,
The traveling waves formed are uniform, and there is no phenomenon such as an increase in torsional vibration.

Therefore, it is possible to solve the disadvantages of the conventional example, such as a decrease in conveyance speed and an increase in fluctuations in conveyance speed.

[Effects of the Invention] As described above, according to the present invention, since the elastic body is arranged at an angle so as not to press and pinch the sheet between the sheet 23 feeding surfaces of the other pair of elastic bodies, the elastic body There is no need to process steps on the body surface, the rigidity of the elastic body can be made uniform, and sheets can be fed with high precision without reducing sheet conveyance speed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a sheet feeding device according to the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. A schematic diagram of the sheet feeding device, and FIG. 5 is a sectional view of the main part thereof. 13... Sheet 19-1.19-2... Vibrator 20-1.20-2... Elastic body 2O-1a, 2O-2a, 2O-1b, 2O-2b -
Straight section and 4 others

Claims (1)

[Scope of Claims] 1. A sheet having a pair of elastic bodies which are excited to produce progressive vibration by an electro-mechanical energy conversion element and which are arranged opposite to each other, and which is sandwiched between the elastic bodies. In the sheet feeding device that conveys the sheet by applying a conveying force to the sheet, the pair of elastic bodies are formed so that the sheet conveying surfaces, in which the direction of the sheet conveying force is opposite to each other, are formed symmetrically with respect to the sheet conveying direction. A sheet feeder characterized in that both elastic bodies are inclined with respect to the sheet transport path so as to press and hold the sheet on one sheet transport surface side of the elastic body and to form a gap on the other sheet transport surface side. Device.