JPH02209337A - sheet feeding device - 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 (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 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.

Further, the elastic body 11 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 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.

However, in the conventional apparatus as described above, there is a drawback that the sheet transport force fluctuates due to changes in temperature, humidity, etc., and the transport speed or transport distance during constant distance transport also fluctuates. As a means to solve this problem, it is conventionally known to detect the sheet transport speed etc. using an optical encoder or the like and perform feedback control, but when this method is adopted, the configuration of the device is complicated, Moreover, it was inevitable that it would be expensive.

(Object of the Invention) An object of the present invention is to provide a sheet with a simple structure that eliminates fluctuations in the transport speed of the sheet or the transport distance during constant distance transport due to changes in the external environment, and provides stable transport performance. The purpose of the present invention is to provide a feeding device.

(Features of the Invention) In order to achieve the above object, the present invention includes a first detection means for detecting that a sheet that has started to be conveyed has passed a first position, and a first detection means that is separated from the first position by a certain distance. a second detection means for detecting that the vehicle has passed through a second position, and the first and second detection hands.

The time required to transport a certain section is calculated based on the signal from the stage, and the frequency voltage applied to the vibrator by the subsequent sheet conveying means is controlled according to this time, and the remaining section is transferred. A certain section in the first half of the sheet conveyance section is set as a run-up section, the length of time required to transfer that section is determined, and the subsequent time is determined based on the length of that time. It is characterized in that the frequency voltage level applied to the vibrator is controlled, that is, the vibration conditions of the elastic body are determined.

It also includes a timer for measuring a predetermined time from the start of sheet transport, a sheet transport position detecting means for detecting the transport position of the sheet at each time during transport, and a signal from the timer and the sheet transport position detecting means. control means for calculating the distance traveled in a certain period of time based on the determined distance, controlling the frequency voltage applied to the vibrator by the sheet conveying means thereafter, and controlling the distance of movement in a certain period of time thereafter; This method determines how far the sheet is transported in a certain period of time, and then controls the frequency voltage level applied to the vibrator based on the length of the distance, that is, determines the vibration conditions of the elastic body. It is characterized by the following.

(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
is an oscillator, 8a and 8b are light emitting elements, 9a and 9b are light receiving elements, 10 is an energy absorption section, and 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 l by an oscillator 7. do. The vibrators 2 and 4 generate electricity as the elastic bodies 5 and 6 vibrate. The generated electrical energy is dissipated by an energy absorbing section 1o made of a resistor or the like. Therefore, the vibration becomes a traveling wave without being reflected. When the bending vibration of the elastic body 5.6 becomes a traveling wave, 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.

The light emitting elements 8a, 8b and the light receiving element 9a described above.

9b has the role of detecting the presence or absence of a sheet, and when there is no sheet, the light emitted from the light emitting element 8a is received by the light receiving element 9a, and an on signal is input to the controller CNT. When the sheet is conveyed and reaches a certain position between the light emitting element 8a and the light receiving element 9a, the light is cut off and the signal to the controller CNT is reversed from on to off. The controller CNT determines whether the sheet has reached the normal position based on the on/off signal from the light receiving element 9a.
The same applies to the light emitting element 9b and the light receiving element 9b.

By the way, sheet feeding devices in machines such as copying machines and printers are required to have a constant feeding speed or a constant feeding amount during intermittent feeding, but the sheets used in such devices, such as paper, etc. The frictional properties of the material tend to change due to changes in temperature, humidity, etc. As a result, conventional devices of this type have had problems with stability in conveyance performance. As a means to solve this problem, it has been known to detect the sheet feeding speed and position using an optical encoder and perform feedback control, but as mentioned above, these methods are complicated and expensive. It had the disadvantage of becoming a thing.

Therefore, in the device of this embodiment, as described above, when the inserted sheet reaches the location where the light emitting element 8a and light receiving element 9a pair are provided, the signal changes from on to off, assuming that it has been conveyed to a certain fixed position. (Because the light is blocked by the sheet) When the sheet is further conveyed and reaches the location where the light emitting element 8b and light receiving element 9b pair are provided, the signal will similarly change from on to off. This signal change is detected by the controller CNT, which measures the time interval from the time of the signal change of the light receiving element 9b to the time of the signal change of the light receiving element 9b, and determines the fixed position corresponding to each element. The time required to move the sheet distance is calculated, and the desired fixed time required between the time capture and the end of sheet conveyance is compared, and the conveyance speed corresponding to the subsequent conveyance distance is controlled (the frequency to the oscillator 7 is (by changing the voltage).

That is, when an external environment change occurs, for example, an increase in humidity, the coefficient of friction of the paper decreases, the transfer force of the feed device decreases, and the feed speed decreases. Alternatively, during intermittent feeding, the conveyance performance fluctuates, such as a decrease in the amount of feed. In this embodiment, the change in the transfer force is known by measuring the change in the moving distance in the above-mentioned fixed section, and based on this result, the vibration of the elastic body 5.6 is controlled, and the second position (8b, 9b vs. position) The subsequent transfer force is changed so that the overall moving time is always constant.

For example, if the travel time is long, the frequency voltage applied to the vibrator 1.3 is increased in accordance with the length of the time to compensate for the decreased transport force and maintain a certain transport force. Although changes in the external environment change over time, they usually occur slowly over time, so even if the subsequent driving conditions are determined based on the conditions in the above-mentioned period, the conveyance performance will be affected within the entire sheet conveyance time. It becomes sufficiently stable.

According to this embodiment, since a certain section is set as a run-up section and subsequent driving conditions are determined from the travel time of that section, the stability of conveyance performance can be improved with a simple structure. .

b is the second detection means according to claim 1, and controller C
NT corresponds to the control means, respectively. The timing means, sheet transport position detection means, and control means according to claim 2 are as described in the following modified examples.

(Modified Example) In this embodiment, the method of determining the driving conditions based on the travel time in a certain section has been mainly described, but as described in the examples, there is another method that determines the driving conditions based on the travel distance in a certain period of time. It is also effective to determine the In this case, as a means for detecting the constantly changing conveyance position of the sheet, for example, a -dimensional image sensor, a timer for measuring a certain period of time, etc. are required.The vibration conditions of the elastic body are determined as described above. Similar to the embodiment, this is possible using the controller. This method of measuring the moving distance is effective for devices that perform intermittent quantitative feeding.

(Effects of the Invention) As explained above, according to the present invention, a certain section in the first half of the sheet conveyance section is set as a run-up section, the length of time required to transfer the section is determined, and the length of the time is determined. According to
Alternatively, it is easy to calculate how far the sheet is transported in a certain period of time, and then control the frequency voltage level applied to the vibrator from then on depending on the length of the distance, in other words, determine the vibration conditions of the elastic body. With this configuration, it is possible to eliminate fluctuations in the transport speed of the sheet or the transport distance during constant distance transport due to changes in the external environment, thereby making it possible to stabilize the transport performance.

[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...
...Light emitting element, 9a, 9b... Light receiving element, 1o
・・・・・・Energy absorption L CNT−・−・−controller. Figure 2 Figure 4

Claims (2)

[Claims] (1) An elastic body to which a vibrator is fixed, and a sheet that is conveyed by applying a frequency voltage to the vibrator to form a traveling wave in the elastic body and applying a transporting force to the sheet pressed against the surface of the elastic body. A sheet feeding device comprising: a first detection means for detecting that a sheet that has started to be transported has passed a first position; and a second position that is separated by a certain distance from the first position. A second detection means detects the passage, and the time required to travel a certain section is calculated based on the signals from the first and second detection means, What is claimed is: 1. A sheet feeding device comprising: a control device for controlling a frequency voltage applied to a vibrator by a sheet feeding device and determining a transfer time for the remaining section. (2) An elastic body to which a vibrator is fixed, and a sheet that is conveyed by applying a frequency voltage to the vibrator to form a traveling wave in the elastic body and applying a transporting force to the sheet pressed against the surface of the elastic body. a sheet feeding device comprising: a timing device for counting a predetermined time from the start of sheet feeding; a sheet transfer position detecting device for detecting the transfer position of the sheet at each time during transportation; The distance traveled in a certain period of time is determined based on the signal from the sheet transport position detection means, and the frequency voltage applied to the vibrator by the sheet transport means thereafter is controlled according to the distance, and the frequency voltage applied to the vibrator is thereafter constant. A sheet feeding device comprising: a control means for controlling a transport distance in time.