JPH04116037A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To reduce the occurrence of unevenness in a sheet feed speed by sizing a contact part between a resilient body and a sheet such that a contact length in a sheet conveying direction is 5mm or more and a total contact length in the direction of the width of a sheet is 1mm or more. CONSTITUTION:A resilient material 12 is supported to a bottom plate 18, and a resilient material 11 is supported to a press support member 16. The resilient material 11 presses a sheet 13 by means of a proper force through spring property which the support member 16 has, and nips the sheet 13 in corporation with the resilient material 12. A frequency voltage is applied on vibrators 14-1, 14-2, 15-1 (located to the back of the sheet 13), and 15-2 located to the resilient materials 11 and 12, respectively, to convey the sheet 13. The resilient materials 11 and 12 are formed such that a length L in a sheet conveying direction of a contact part between the resilient materials 11 and 12 and the sheet 13 is 5mm or more and width H is lmm or more. This constitution makes it clear from an experiment result that the occurrence of unevenness in a feed speed of the sheet 13 is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] (Field of Application of the Invention) The present invention is applicable to computers, copying machines, facsimile machines, word processors, typewriters, and other various machines equipped with a mechanism for feeding sheets. The present invention relates to a sheet feeding device.

[Prior Art] 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 Application Laid-open No. 59-177243. Ta.

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 180 degrees. The bending vibration of .12 progresses on the sheet 13 side so that each image portion always faces each other. At this time, if we focus on a mass point on the surface of the elastic body 11, 12, for example in the image area, the mass point generally moves in an elliptical orbit. In FIG. 3, 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 direction of movement of the mass point of the convex part is the elastic body it, 12
In both cases, the direction 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 transport 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 bodies 11 and 12 is small, and the sheet transport 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. 4 shows an example of a device for generating the sheet conveying force as described above, and in the figure, reference numerals 11, 12, and 13 are the elastic body and sheet described above. Also, 14-1.14-2.
15-1 (not shown) and 15-2 are the elastic bodies 11.
A vibrator fixed on 12, 16 a pressing support member, 17
-1.17-2 is a supporting 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. Also, the elastic body 1
1 presses the sheet 13 with an appropriate force due to the spring properties of the pressing support member 13 and holds the sheet 13 together with the elastic body 12. By applying a certain frequency voltage to each vibrator and applying vibration to the elastic bodies 11 and 12, the convex portions are always opposed to each other as described above, so 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.

In the conventional device, the dimensions of the contact portion between the elastic body and the sheet are 3 mm in the sheet conveyance direction and 0.5 mm in the sheet width direction.
The sheet was conveyed with a size of mm.

[Problem to be solved by the invention]

Figures 7, 8, and $9 show recording paper currently used in copying machines, facsimile machines, word processors, etc., 3F! The feed speed was measured when the type was conveyed by a sheet feed device using the above-mentioned elastic body (contact area 3 mm x 0.5 mm), and the average feed speed was measured for papers A, B, and C. A speed unevenness of 12% to 20% occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding device that can solve the above-mentioned problems and feed sheets with high accuracy by minimizing unevenness in sheet feeding speed.

[Means for Solving the Problems] The gist of the present invention is to press a sheet between a pair of elastic bodies, and apply electric current to the pair of elastic bodies so as to generate traveling wave vibrations. A sheet feeding device that is excited by a mechanical energy conversion element and applies a transporting force to the sheet by a traveling wave formed in the elastic body, the sheet feeding device having one or more elastic body pairs, the one or more elastic body pairs The total contact length of the contact area between the
n or more, and the total contact length in the sheet width direction is lll1 m or more.

[Function] The sheet feeding device configured as described above prevents sheet feeding speed unevenness by setting the contact length between the elastic body and the sheet in the sheet conveying direction to 5 mm or more and the contact length in the sheet width direction to 1 mm or more. becomes less.

Embodiments Embodiment 1 FIG. 1 is a perspective view showing Embodiment 1 of a sheet feeding device according to the present invention, which can be used as a printer device by, for example, providing a printing mechanism in the sheet conveying section.

It should be noted that this embodiment has basically the same structure as the conventional example shown in FIG.

In this embodiment, a pair of upper and lower elastic bodies 11 forming a sheet conveyance section are used.
．． The dimension of No. 12 in the sheet conveyance direction is 5 mm, and the dimension H in the sheet width direction is 1 mm.

10 to 15 show the above-mentioned recording paper A.

Continuous conveyance was performed using three types of elastic bodies, B and C, using the dimensions of the elastic body in the sheet conveyance direction and the dimension H in the direction perpendicular to the sheet conveyance direction as parameters, and the speed unevenness in a certain section of the recording paper being conveyed was measured. This is a graph.

From these data, it can be seen that speed unevenness can be significantly reduced if the distance is 5 mm or more in the sheet transport direction and 1 m or more in the direction perpendicular to the sheet transport direction.

In Figures 16, 17, and 18, L = 5 mm.

With a pair of elastic bodies 11.12 of H= 1 ma+, A
, B, and C. The results show that the speed unevenness has improved to 2 to 3%.

As explained above, if the size of the sheet contacting portion of the elastic body is 5+nm or more in the sheet conveyance direction and 1 mm or more in the direction perpendicular to the sheet conveyance direction, it is effective to reduce the unevenness in the feed speed.

Note that this dimension represents the area of the contact area between the elastic body and the sheet, and even if the elastic body has various other shapes or multiple pairs of elastic bodies are used, the contact area with the sheet will be A similar effect can be obtained if the portion satisfies the above-mentioned dimensions, and such an example is shown in Example 2.3 below.

Embodiment 2 The second section is a perspective view showing Embodiment 2 of the present invention. In this embodiment, a first sheet driving section A consisting of vertically paired elastic bodies 11 and 12 and a second sheet driving section B consisting of vertically paired elastic bodies 19 and 20 are arranged at right angles to the sheet conveyance direction. The dimensions of the elastic bodies in the sheet conveying direction in each sheet conveying section A and B are 5 mm, and the dimension H in the direction perpendicular to the sheet conveying direction is 0.5 ma+. In this case, the total dimension of the sheet in contact with the elastic body in the direction perpendicular to the sheet conveyance direction is 1 mm, and the contact length in the sheet conveyance direction is 5 mm, resulting in the same contact area as in Example 1 above. , a similar effect can be obtained.

Example 3 FIG. 6 shows a perspective view of the third embodiment.

In this embodiment, a sheet conveying section A and a second sheet conveying section B are arranged in series along the sheet conveying direction, and the elastic body in each sheet conveying section A and B is The dimension H is 2.5 mm, and the dimension H in the direction perpendicular to the sheet conveyance direction is 1+nm.

In this case, the total dimension of the sheet in contact with the elastic body in the sheet conveyance direction is 5 mm, and the dimension in the direction perpendicular to the sheet conveyance direction is 1 mm, so as a result, the same contact area as in Example 1 is obtained, and the same effect can be obtained.

[Effects of the Invention] As explained above, according to the present invention, the dimensions of the elastic body used in the sheet conveyance device are set to 5 mm or more in the sheet conveyance direction and 1 mm or more in the sheet width direction. Unevenness in feeding is reduced and stable sheet feeding is possible.

[Brief explanation of the drawing]

Fig. 1: Schematic diagram showing Embodiment 1 of the sheet feeding device according to the present invention, Fig. 2: Schematic diagram of Embodiment 2, Fig. 3: Diagram explaining the sheet conveyance principle, Fig. 4: Conventional sheet feeding device. An external perspective view showing the device, FIG. 5: A diagram explaining the sheet conveying force generating section, FIG. 6: A schematic diagram of Embodiment 3, FIGS. 7, 8, and 9: A conventional sheet feeding device Figures 10, 11, 12, and 13 show data on measuring the feed speed during conveyance. Figures 14 and 15: Data obtained by measuring feed speed unevenness using the dimensions of the elastic body as a parameter. Measured data, 9. Elastic sheet 14-1.14-2 Vibrator and 4 other people Figure Figure Figure Paper position! (m) 1.0 1.5 Hl++nl Figure 12 Figure 10 L (mml Figure 14 L fIw++1 H (surface) H-Measurement range 11 17 Figure paper position fmm1 Paper position (nwnl

Claims (1)

[Claims] A sheet is pressed between a pair of elastic bodies, and the pair of elastic bodies is excited by an electro-mechanical energy conversion element to generate traveling wave vibration, and the traveling waves formed in the elastic bodies are excited. A sheet feeding device that applies a transporting force to the sheet by a force, which has one or more pairs of elastic bodies, and the contact portion between the one or more pairs of elastic bodies and the sheet has a total contact length in the sheet conveying direction. A sheet feeding device characterized in that the total contact length in the sheet width direction is 5 mm or more, and the total contact length in the sheet width direction is 1 mm or more.