JPH03200645A - Separate paper 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 Field of the Invention The present invention relates to a paper separation device used in automatic paper feeding mechanisms of various printers.

2. Description of the Related Art At present, an automatic paper feeding mechanism exists as one of the mechanisms for improving the practicality of equipment such as printers. There is a paper conveying device 4 that presses and supports a rotatable friction roller 2 and conveys a paper 3 while sandwiching it between these members. However, this is not practical because it is not possible to separate and feed the stacked sheets 3 one by one.

Therefore, as a device for separating and feeding a plurality of stacked sheets 3, there is a device as illustrated in FIG. 5. In this paper separation and feeding device 5, two friction rollers 6.7 having different surface frictions, which are arranged opposite to each other via a paper transport path, rotate in the same direction.
If the frictional resistance between the sheets 3 is PPP, then jI
! Each frictional resistance F FP between the rubbing roller 6°7 and the paper 3,
F RP is formed such that F vp > F RP > F pp .

By doing so, the paper separation and feeding device 5 can separate and feed the plurality of sheets 3 one by one between the two friction rollers 6.7. However, the paper separation/feeding device 5 having the above-described structure has a structure in which the friction rollers 6.7, which tend to be large due to their cylindrical shape, are arranged opposite each other, and the friction rollers 6.7 are arranged in opposite directions. Motors and gear trains that drive rotation (
(not shown), it is structurally difficult to make the device smaller and thinner.

Therefore, a piezoelectric actuator 8 exists as a device that has the function of conveying the paper 3 and can be made smaller and thinner. This piezoelectric actuator 8 is, for example, a combination of an elastic material formed in a flat plate shape and a piezoelectric element.
When an alternating current voltage is applied to the piezoelectric element, vibrations called traveling waves are generated. Therefore, as illustrated in FIG. 6, it is known that when the piezoelectric actuator 8 that presses the paper 3 with a spring 9, a pressing plate 10, etc. is driven, the paper 3 travels in the opposite direction to the traveling wave generated by the piezoelectric actuator 8. ing.

Here, as an apparatus for conveying paper using such a piezoelectric actuator 8, there is an apparatus disclosed in Japanese Unexamined Patent Publication No. 1-214461. This paper conveyance device 11
As illustrated in FIG. 7, a pair of piezoelectric actuators 12 and a pair 3 placed opposite each other are biased to press each other, and these piezoelectric actuators 12,
The pair of sheets 3 generate traveling waves in the same direction, so that the sandwiched paper 3 is conveyed.

Problems to be Solved by the Invention The paper separation and feeding device 5 as illustrated in FIG. 5 is capable of separating and feeding a plurality of stacked printing papers 3 one by one. Since the rotating parts 7 move in opposite directions, it is structurally difficult to make it smaller and thinner.

On the other hand, the paper conveyance device 11 as illustrated in FIG. 7 conveys the paper 3 in a pair of three piezoelectric actuators 12 that do not require mechanical operation, so it is easy to make the device smaller and thinner. The paper conveying device 11 does not have a function of separating and feeding a plurality of stacked papers 3.

Means for Solving the Problems The invention as set forth in claim 1 comprises disposing a pair of piezoelectric actuators, each of which is made of a flat elastic body and a piezoelectric element and whose traveling waves are generated in opposite directions, facing each other via a paper conveyance path. , a pair of piezoelectric actuators is provided with a biasing means that biases the opposing surfaces in a direction in which they press each other, and assuming that the frictional force generated between the sheets to be separated is FP, the piezoelectric actuator whose traveling wave direction coincides with the paper feeding direction is provided. Frictional force FF generated between
and the frictional force FR generated between the piezoelectric actuator and the paper whose traveling wave direction is opposite to the paper feeding direction, F F > F
In the invention according to claim 2, wherein each piezoelectric actuator is characterized so as to satisfy the relationship R>F p , the pair of piezoelectric actuators are arranged such that the distance between the opposing surfaces becomes smaller in the paper feeding direction.

According to a third aspect of the present invention, a biasing means is provided which includes an actuator whose biasing force acting in a direction perpendicular to the paper feeding direction is variable.

According to a fourth aspect of the present invention, a control means is provided for controlling the driving of the piezoelectric actuator whose traveling wave direction coincides with the paper feeding direction based on a detection value of a sensor provided on the paper conveyance path.

A pair of piezoelectric actuators, each made of a flat elastic body and a piezoelectric element, whose traveling waves are generated in opposite directions, are arranged facing each other across the paper conveyance path, and the pair of piezoelectric actuators are moved in a direction in which the opposing surfaces press against each other. Assuming that a biasing means for biasing is provided and the frictional force generated between the sheets to be separated is FP,
F By forming each piezoelectric actuator to satisfy the relationship F>F R>Fp, a conveying force in the direction opposite to the traveling wave direction is applied to each sheet of paper that comes into contact with these piezoelectric actuators. A plurality of sheets of paper held between these piezoelectric actuators are separated and fed one by one.

Further, the invention according to claim 2 provides a method for disposing a pair of piezoelectric actuators such that the distance between opposing surfaces decreases in accordance with the sheet feeding direction, so that the sheet of paper protrudes from the group of sheets fed between the piezoelectric actuators in the sheet feeding direction. Since the conveyance direction comes into contact with a piezoelectric actuator whose conveyance direction is opposite to the paper feeding direction, more reliable paper separation and feeding can be realized.

According to the third aspect of the invention, by providing a biasing means consisting of an actuator whose biasing force acting in a direction perpendicular to the paper feeding direction is variable, the pressing force of the biasing means can be increased or decreased to increase or decrease the pressing force of the pair of piezoelectric actuators. It is possible to adjust the paper conveyance force generated during the process.

Furthermore, the invention according to claim 4 provides a control means for controlling the drive of the piezoelectric actuator whose traveling wave direction coincides with the paper feeding direction based on the detected value of the sensor provided on the paper conveyance path. In synchronization with the fact that only one sheet of paper exists between the actuators, the drive of the piezoelectric actuator whose paper conveying force is opposite to the paper feeding direction is controlled.
It is possible to prevent or increase paper conveyance force.

Embodiment An embodiment of the invention set forth in claim 1 will be described based on FIG. First, in the separation sheet feeding device 14 of this embodiment, a reverse actuator 15 and a pair of drive actuators 15 and 6, which are a pair of piezoelectric actuators that generate traveling waves in opposite directions, are arranged opposite to each other via a sheet conveyance path. Here, due to the elastic force of a spring 18, which is a biasing means installed between the reverse actuator 15 and the frame 17, the pair of piezoelectric actuators 15 and the pair 6 are urged in a direction in which opposing surfaces press against each other. Forced.

Assuming that the frictional force generated between the paper sheets 3 to be separated is FP, this separation paper feeding device 14 operates between a drive actuator 16 whose traveling wave direction coincides with the paper feeding direction and the paper 3
The frictional force F generated between

The piezoelectric actuators 15 are arranged so that the frictional force F3 generated between the reverse actuator 15 whose traveling wave direction is opposite to the paper feeding direction and the paper 3 satisfies the relationship FF>FR>Fp.
, one pair of six opposing surfaces are formed.

In such a configuration, this separation paper feeding device 14:
First, as illustrated in FIG. 1(a), a plurality of sheets 3 to be separated and fed are inserted between the opposing surfaces of the pair of piezoelectric actuators 15 and 6, and the piezoelectric actuators (not shown) When a predetermined AC voltage is applied, traveling waves are generated in opposite directions.

In this case, as mentioned above, the frictional force between each member is FP.

FFPFR is FF>FR>F.

Therefore, the sheets 3 that come into contact with the reverse actuator 15 are sequentially discharged backward, and as illustrated in FIG. 1(c), the pair of piezoelectric actuators 1
A sheet of paper 3 remains between 5 and 6, and this paper 3 is transported forward by the combined transport force (FP-FR) of the pair of piezoelectric actuators 15 and 6.

Therefore, this paper separation/feeding device 14 can separate and feed the one sheet that is in contact with the drive actuator 16 from among the plurality of sheets 3 inserted between the pair of piezoelectric actuators 15 and 6, and furthermore, This separation and feeding is realized by a pair of piezoelectric actuators 15 and 16 that do not require mechanical operation such as a rotationally driven friction roller.
It is easy to make the device smaller and thinner.

Next, an embodiment of the invention according to claim 2 will be described based on FIG. In this separation sheet feeding device 19, a pair of piezoelectric actuators 15 and a pair 6 are arranged such that the distance between their opposing surfaces becomes smaller in the sheet feeding direction. Note that the other structure is the same as that of the paper separation and feeding device 14 described above.

In such a configuration, this separation paper feeding device 19:
Since the paper 3 that protrudes in the paper feeding direction with respect to other papers 3 comes into contact with the reverse actuator 15, more reliable paper separation and feeding can be performed.

Further, an embodiment of the invention according to claims 3 and 4 will be described based on FIG. 3. In this separation sheet feeding device 20, a piezoelectric actuator 21, which is a biasing means, is attached between the reverse actuator 15 and the frame 17.
An optical sensor 22 is arranged on the drive actuator 16 at a position facing the paper 3. The sensor 22 and each piezoelectric actuator 15, 16° 21 are connected to a control circuit 23 which is a control means.

In such a configuration, this separation paper feeding device 20 has the following functions:
The conveying force for the paper 3 is adjusted by driving the piezoelectric actuator 21 controlled by the control circuit 23 and varying the pressing force between the pair of piezoelectric actuators 15 and 6.

In other words, the frictional force f generated between objects is f = μN, where the friction coefficient between the contact surfaces of the objects is μ and the normal stress between the contact surfaces is N. Therefore, the frictional force f between the sheets 3 is μ2, and the drive Assuming that the friction coefficient between the actuator 16 and the paper 3 is μm, and the friction coefficient between the reverse actuator 15 and the paper 3 is μ8, the frictional forces FP, FP, and FR between the aforementioned members are as follows: FP=μ, N FF=μFN FR =μRN (However, μm>μ8>μP).

Then, when the piezoelectric actuator 21 is driven as described above to increase the vertical stress between the pair of piezoelectric actuators 15 and 6 from N to N', the sheet conveying force becomes (Fp
FR) to (FF FR'), but in this case, FFFR=(μ, -μR)N'>(μ, -μR)N=F
Since it becomes F-FR, the paper conveyance force increases by about N'/N times.

Therefore, in this separation paper feeding device 20, the control circuit 23, which monitors the moving speed of the paper 3 on the drive actuator 16 using the optical sensor 22, increases the pressing force of the piezoelectric actuator 21 when detecting a delay in the speed. It looks like this. In other words, when there is one sheet of paper 3 located between the pair of piezoelectric actuators 15 and 6, the paper conveyance force acting on it changes from FF to (FF FR) and the conveyance speed is delayed, so the By driving the piezoelectric actuator 21 to increase the paper conveyance force, reliable paper separation and good paper conveyance can be realized.

Further, as in the invention described in claim 4, it is also possible to control the drive of the reverse actuator 15 based on the speed detection of the optical sensor 22. In this case, the position between the pair of piezoelectric actuators 15 and 6 is When only one sheet of paper 3 is left, the drive of the reverse actuator 15 is stopped and the direction of the traveling wave is reversed to prevent or increase the paper conveyance force, thereby ensuring reliable paper separation and rapid paper conveyance. It can be realized.

Effects of the Invention As described above, the invention according to claim 1 includes a pair of piezoelectric actuators each comprising a flat elastic body and a piezoelectric element and generating traveling waves in opposite directions, which are arranged opposite to each other via a paper conveyance path. , a pair of piezoelectric actuators is provided with a biasing means that biases the opposing surfaces in a direction in which they press each other, and assuming that the frictional force generated between the sheets to be separated is FP, the piezoelectric actuator whose traveling wave direction coincides with the paper feeding direction is provided. The frictional force FF generated between the piezoelectric actuator and the paper and the frictional force FIl generated between the piezoelectric actuator whose traveling wave direction is opposite to the paper feeding direction and the paper satisfy the relationship FF>Fp>FPP. By forming each piezoelectric actuator at Since a conveyance force acts in the paper feeding direction on the paper that comes into contact with the opposite piezoelectric actuators, the plurality of papers inserted between these piezoelectric actuators are separated and fed one by one.
Moreover, since this separation feeding is realized by a piezoelectric actuator that does not require mechanical operation such as a rotationally driven friction roller, it is easy to make the device smaller and thinner. The present invention arranges a pair of piezoelectric actuators so that the distance between their facing surfaces decreases in accordance with the paper feeding direction, so that the paper that protrudes in the paper feeding direction from a group of papers fed between the piezoelectric actuators is arranged so that the conveyance direction is the paper feeding direction. Since the piezoelectric actuator comes into contact with the piezoelectric actuator opposite to the direction, it is possible to realize more reliable paper separation and feeding. By providing a biasing means consisting of an actuator, it is possible to adjust the paper conveying force generated between a pair of piezoelectric actuators by increasing or decreasing the pressing force of this biasing means, so that the biasing means can be driven at a predetermined timing. According to the fourth aspect of the present invention, the traveling wave direction matches the paper feeding direction based on the detected value of a sensor provided on the paper transport path. By providing a control means for controlling the drive of the piezoelectric actuators, the drive of the piezoelectric actuators whose paper conveying force is opposite to the paper feeding direction is controlled in synchronization with the fact that only one sheet of paper exists between the pair of piezoelectric actuators. Therefore, it is possible to prevent or increase the paper conveyance force, thereby achieving both reliable paper separation and rapid paper conveyance.

[Brief explanation of drawings]

FIG. 1 is an operation explanatory diagram showing an embodiment of the invention as claimed in claim 1, FIG. 2 is a side view showing an embodiment of the invention as claimed in claim 2,
FIG. 3 is a side view showing an embodiment of the invention according to claims 3 and 4, and FIGS. 4 to 7 are side views showing a conventional example. 9...paper, 14゜19゜20...separation paper feeding device, 15゜6...piezoelectric actuator, ■8゜biasing means, 22...sensor, 23...control means applicant Ricoh Co., Ltd. 1 figure

Claims (1)

[Claims] 1. A pair of piezoelectric actuators, each of which is made of a flat elastic body and a piezoelectric element and generate traveling waves in opposite directions, are arranged facing each other via a paper conveyance path, and the pair of piezoelectric actuators are If a biasing means is provided to bias the facing surfaces in a direction in which they press each other, and the frictional force generated between the paper sheets to be separated is F_P, then between the piezoelectric actuator and the paper paper whose traveling wave direction coincides with the paper feeding direction. The frictional force F_F generated at
A separation sheet feeding device characterized in that each of the piezoelectric actuators is formed so as to satisfy the relationship _R>F_P. 2. The paper separation and feeding device according to claim 1, wherein the pair of piezoelectric actuators are arranged such that the distance between the opposing surfaces decreases in the paper feeding direction. 3. The paper separation device according to claim 1, further comprising a biasing means whose biasing force acting in a direction perpendicular to the paper feeding direction is variable. 4. Separated sheet feeding according to claim 1, further comprising a control means for controlling the driving of the piezoelectric actuator whose traveling wave direction coincides with the sheet feeding direction based on the detected value of a sensor provided on the sheet conveying path. Device.