JPH0618343U - Paper transport device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent double feed reliably. [Structure] A separator rubber 8 of a paper pressing plate 5 comes into contact with a conveying roller 2 made of hard rubber with a load, and a paper 4 is fed while being prevented from overrunning. Piezoelectric ceramics 9 is attached to the upper surface of the paper pressing plate 5, and when a voltage is applied to the ceramics 9, a standing wave is generated in the paper pressing plate 5 and the pressing plate 5 vibrates. Then, on the upper surface of the paper pressing plate 5, the piezoelectric ceramic 9 is placed at a position corresponding to a node of a standing wave.
Groove grooves 6a, 6b are provided. In addition, the piezoelectric ceramics 9 is attached to a position corresponding to an antinode between the nodes.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transporting device suitable for being applied to a facsimile device or a printer device, and more particularly to a paper transporting device for transporting paper one by one while preventing so-called double feeding in which a plurality of sheets are simultaneously sent.

[0002]

[Prior art]

 Generally, in this type of paper transporting device, the paper pressing plate is brought into contact with the transporting roller with a predetermined load, and due to the difference in frictional force generated between the transporting roller, the paper and the paper pressing plate, the double feeding of the paper is performed. Was prevented. That is, assuming that the frictional force between the transport roller and the paper is G, the frictional force between the paper pressing plate and the paper is F, and the frictional force between the papers is f, the materials of the respective members are set so that G> F> f. You have selected. As a result, the first sheet is conveyed by the conveying rollers, the second and subsequent sheets are stopped by the sheet pressing plate, and the sheets are conveyed one by one to prevent double feeding.

By the way, when external environmental conditions such as temperature or humidity change, the coefficient of friction between the respective members, which is the initial design condition, changes, and the frictional force between the members also changes accordingly. In particular, f is greater than F. Also becomes large and double feed occurs. Therefore, in the conventional art, a piezoelectric element is fixed to the paper pressing plate, and the piezoelectric element vibrates the paper pressing plate to generate a separating action between the papers to prevent the frictional force f between the papers from increasing. It prevented double feeding.

[0004]

[Problems to be solved by the device]

 Since the above-mentioned conventional paper pressing plate is formed in a flat plate shape, the magnitude of vibration of the paper pressing plate is determined by the displacement of the piezoelectric element. However, there is a limit to the displacement of the piezoelectric element, and it is difficult to vibrate the paper pressing plate beyond the limit, and therefore, there is a drawback that a large effect in preventing double feed cannot be obtained. Therefore, the present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a sheet conveying device capable of reliably preventing double feeding.

[0005]

[Means for Solving the Problems]

 In order to achieve this object, a sheet conveying apparatus according to the present invention prevents a sheet from being conveyed from the second sheet onward by a conveying roller that conveys a sheet and a surface of the conveying roller that is abutted with a load. A sheet conveying device comprising a sheet holding plate for fixing and a piezoelectric element fixed to the sheet holding plate for vibrating the sheet holding plate, wherein a section coefficient corresponding to a vibration node of the sheet holding plate has a section coefficient. The piezoelectric element is formed so as to be small, and the piezoelectric element is arranged in an antinode between the nodes. Further, the sheet conveying device according to the present invention is provided with a supporting member to which a root portion of the sheet pressing plate is attached and which supports the sheet pressing plate in a cantilever manner. A section having a small section modulus is provided between the sheet holding plate and a supporting point for supporting the sheet pressing plate. Further, in the paper transporting device according to the present invention, the mounting portion of the paper pressing plate attached to the support member is arranged at a portion corresponding to a vibration node of the paper pressing plate.

[0006]

[Action]

 According to the present invention, since the section corresponding to the vibration node is formed so that the section modulus is small TP, the shape change at the node of the paper pressing plate becomes large due to the displacement of the piezoelectric element, and the paper pressing plate The displacement of vibration becomes large. Moreover, since the piezoelectric element is arranged in the antinode between the nodes, the displacement of the sheet pressing plate by the piezoelectric element and the waveform of the standing wave are the same. Also, since a section with a small cross-sectional coefficient is provided between the part of the paper pressing plate to which the piezoelectric element is fixed and the support point of the supporting member that supports the paper pressing plate, the vibration of the piezoelectric element is applied to the supporting member. It is difficult to communicate. Further, since the mounting portion of the paper pressing plate that is attached to the support member is arranged at a portion corresponding to the vibration node of the paper pressing plate, the vibration width of the paper pressing plate at the mounting portion is minimized and the vibration of the piezoelectric element is Difficult to communicate with.

[0007]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a paper conveying device according to the present invention, FIG. 2 is a plan view of FIG. 2 and FIG. 2B is a side view of the same, and FIG. It is a side view which shows the relationship of. In these figures, reference numeral 2 is a conveyance roller made of hard rubber, 3 is a paper guide for guiding the paper 4 to the conveyance roller 2, 5 is a paper pressing plate, and 8 is fixed to the lower surface of the paper pressing plate 5 and its tip is fixed. Separator rubber that is a double feed preventing member that is in contact with the surface of the conveying roller 2 with a load, and 9 is a piezoelectric ceramic attached to the upper surface of the paper pressing plate 5.

On the upper surface of the paper pressing plate 5, two parallel grooves 6a and 6b are provided, and the base end side has the same distance as the distance between the grooves 6a and 6b. A pair of mounting holes 7 for mounting the sheet pressing plate 5 on the bracket 10 on the apparatus side are provided at positions separated from the 6b only. In such a structure, when an alternating voltage is applied to the piezoelectric ceramics 9 so that the secondary-mode vibration is generated in the paper pressing plate 5, a standing wave W as shown by a solid line and a two-dot chain line in FIG. It occurs on the plate 5. Here, in this standing wave W, since vibration of the secondary mode is generated, three points A at which no displacement occurs are generated. These points A are called knots, and the midpoint B between them is called the antinode.

The feature of the present invention resides in that the grooves 6a and 6b are provided at positions corresponding to the nodes A, and the piezoelectric ceramics 9 is arranged on one of the antinodes B. As described above, by providing the grooves 6a and 6b in the node A, which is the fulcrum of bending, to form a thin section and reduce the section modulus, the sheet pressing plate 5 is easily bent and the displacement is increased. . Further, by disposing the piezoelectric ceramics 9 on the belly B, the displacement of the sheet pressing plate 5 by the piezoelectric ceramic 9 and the waveform of the standing wave W match, and the electric energy input to the piezoelectric ceramic 9 is the most efficient. It can be converted into vibration of the paper pressing plate 5. From these facts, the separating action between the sheets 4 becomes large as compared with the case where the piezoelectric ceramics are fixed, and as a result, the displacement of the sheet pressing plate 5 also becomes large, and the double feeding of the sheets 4 is further prevented. Be effective.

FIG. 4 is a side view showing the relationship between the paper pressing plate and the waveform of a standing wave according to the second embodiment of the present invention. In the second embodiment, the shape of the sheet pressing plate 5 when the vibration of the third mode is generated by the piezoelectric ceramics 9 is shown. In this case, four joints A are formed, and three grooves 6a, 6b and 6c and a mounting hole 7 are provided at positions corresponding to the joints A, and the same operation as that of the first embodiment described above is performed. Have an effect.

FIG. 5 is a vibration model diagram of a paper pressing plate showing a third embodiment of the present invention. This third embodiment shows a case where a plurality of piezoelectric ceramics 9 are attached, and in this embodiment in which the vibration of the secondary mode is generated, two piezoelectric ceramics 9 are placed at two positions corresponding to the adjacent antinode B. Two piezoelectric ceramics 9 are attached. In this case, the phases of the voltages applied to the two piezoelectric ceramics 9 are shifted so that when one surface side of the paper pressing plate 5 extends in the direction of arrow C, the voltage is applied so that the other adjacent side contracts in the direction of arrow D. is doing. In the third embodiment, since the plurality of piezoelectric ceramics 9 are provided, the displacement of the paper pressing plate 5 becomes larger.

FIG. 6 is a side view of a sheet feeding device showing a fourth embodiment of the present invention, FIG. 7 is a sheet holding plate similarly (a) is a plan view, (b) is a side view, and FIG. 8 is the same. FIG. 6 is a side view showing the relationship between the paper pressing plate and the waveform of a standing wave. The feature of the fourth embodiment resides in that two pairs of notches 11a and 11b are provided on both side surfaces of the sheet pressing plate 5, and these notches 11a and 11b are arranged as shown in FIG. Is provided at a position corresponding to. By providing the notches 11a and 11b having a small section modulus at the position corresponding to the node A, the displacement of the paper pressing plate 5 can be maximized as in the above-described embodiment.

Further, a notch 11 b is provided between the attachment position of the piezoelectric ceramics 9, which is the vibration source, and the attachment hole 7, which is the position where the paper pressing plate 5 is attached to the bracket 10. . Therefore, the vibration generated in the paper pressing plate 5 by applying the voltage to the piezoelectric ceramics 9 is absorbed by the notch 11b, and the vibration from the notch 11b to the mounting hole 9 side is damped. As a result, vibration on the free end side of the paper pressing plate 5 is less likely to be transmitted from the mounting hole 9 to the bracket 10, and vibration is less likely to be generated in the bracket 10, so that the bracket 10 cantilever-supports the paper pressing plate 5. Stabilize. Therefore, the vibration on the free end side of the paper pressing plate 5 is not hindered, and the vibration of the attached separator rubber 8 is not hindered, so that the double feeding can be prevented more effectively.

Further, in this embodiment, the mounting hole 9 is provided at a position corresponding to the node A. Even if the voltage is applied to the piezoelectric ceramics 9, the vibration of the paper pressing plate 5 is less likely to be transmitted to the bracket 10 attached at the point A where the paper pressing plate 5 is not displaced at all. Further, the vibration on the free end side of the paper pressing plate 5 is not disturbed, and the double feed prevention is made more effective.

FIG. 9 shows a fifth embodiment of the present invention and is a side view showing the relationship between the paper pressing plate and the waveform of a standing wave. In the fifth embodiment, a case where vibration of the third-order mode is generated by the piezoelectric ceramics 9 is shown. Notches 11a and 11b are provided at two places of the node A generated at four places, and the mounting hole 7 is provided at one place. Is provided. With such a configuration, the sheet pressing plate 5 is easily vibrated, and the vibration is less likely to be transmitted to the bracket 10, so that the same effect as that of the fourth embodiment described above can be obtained.

In the above-described embodiment, the groove 6 or the notches 11a and 11b are provided at the position corresponding to the node A to reduce the section modulus, but the present invention is not limited to the groove and the notch, and various design changes can be made. It is possible that the sheet pressing plate 5 is easily bent at the node A which is the fulcrum of bending, or the surface area coefficient is small so that the vibration of the sheet pressing plate 5 is hard to be transmitted to the bracket 10. .

[0017]

[Effect of device]

 As described above, according to the present invention, the piezoelectric element is fixed to the paper pressing plate that comes into contact with the surface of the conveying roller with a load to prevent the conveyance of the second and subsequent sheets of paper, and the vibration of the paper pressing plate is further fixed. Since the section corresponding to the node is formed so that the section modulus is small, the shape change at the node of the paper pressing plate, which is the fulcrum of bending, becomes large with respect to the displacement of the piezoelectric element, and therefore the paper pressing plate The displacement of vibration becomes large. In addition, since the piezoelectric element is placed in the antinode between the nodes, the displacement of the sheet pressing plate due to the piezoelectric element and the waveform of the standing wave match, and the electrical energy input to the piezoelectric element is the most efficient sheet pressing. It can be converted into the vibration of the plate, and this also increases the displacement of the vibration of the paper pressing plate, and as a result, the separating action of the paper is improved and the double feeding of the paper can be prevented more reliably.

Further, according to the present invention, the section modulus is small between the portion of the paper pressing plate to which the piezoelectric element is fixed and the support point of the supporting member for supporting the paper pressing plate to which the paper pressing plate is attached. Since the part having the section is provided, the vibration generated in the sheet pressing plate by the piezoelectric element is absorbed at the part having a small section modulus and is damped at the mounting hole side. As a result, the vibration on the free end side of the paper pressing plate is less likely to be transmitted to the bracket, the vibration is less likely to occur in the bracket, and the cantilever support state of the paper pressing plate by the bracket is stable. Therefore, the vibration on the free end side of the paper pressing plate is not hindered, and the vibration of the heavy running prevention member attached to the paper pressing plate is not hindered, so that the double feeding is further effectively prevented.

Further, according to the present invention, since the mounting portion of the paper pressing plate attached to the supporting member is arranged at a portion corresponding to a vibration node of the paper pressing plate, the bracket does not displace the paper pressing plate at all. Since it is attached to the part, the vibration of the paper pressing plate is less likely to be transmitted to the bracket, the vibration is less likely to occur to the bracket, and the cantilever support state of the paper pressing plate by the bracket is stable. Therefore, the vibration on the free end side of the paper pressing plate is not hindered, and the vibration of the heavy running prevention member attached to the paper pressing plate is not hindered, and the double feed prevention is made more effective. .

[Brief description of drawings]

FIG. 1 is a side view of a sheet conveying device according to the present invention.

2A and 2B show a paper pressing plate of a paper transporting device according to the present invention, wherein FIG. 2A is a plan view and FIG. 2B is a side view.

FIG. 3 is a side view showing the relationship between the paper holding plate and the waveform of a standing wave of the paper transporting device according to the present invention.

FIG. 4 is a side view showing the relationship between the sheet pressing plate and the waveform of a standing wave of the second embodiment of the sheet conveying device according to the present invention.

FIG. 5 is a side view showing the relationship between the sheet pressing plate and the waveform of a standing wave in the third embodiment of the sheet conveying device according to the present invention.

FIG. 6 is a side view of a fourth embodiment of the sheet conveying device according to the present invention.

7A and 7B show a paper pressing plate of a fourth embodiment of the paper conveying device according to the present invention, FIG. 7A is a plan view, and FIG. 7B is a side view.

FIG. 8 is a side view showing a relationship between a sheet pressing plate and a waveform of a standing wave in a sheet conveying device according to a fourth embodiment of the present invention.

FIG. 9 is a side view showing the relationship between the sheet pressing plate and the waveform of a standing wave in the sheet conveying device according to the fifth embodiment of the present invention.

[Explanation of symbols]

 2 Conveyor roller 4 Paper 5 Paper pressing plate 6 Groove 8 Double feed prevention member 9 Piezoelectric ceramics 11 Notch

Claims (3)

[Scope of utility model registration request] 1. A transport roller for transporting a sheet, a sheet retainer plate having a load on the surface of the transport roller to abut against the second and subsequent sheets of sheet, and a sheet retainer plate fixed to the sheet retainer plate. In a sheet conveying device including a piezoelectric element that vibrates a sheet pressing plate, a portion corresponding to a vibration node of the sheet pressing plate is formed so as to have a small sectional modulus, and the piezoelectric element is divided into a node and a node. A sheet conveying device, which is arranged on an antinode. 2. A transport roller for transporting a sheet, a sheet retainer plate having a load on the surface of the transport roller to abut against the second and subsequent sheets, and a root portion of the sheet retainer plate. In a paper conveying device comprising a support member attached to support the paper holding plate in a cantilever manner and a piezoelectric element fixed to the paper holding plate and vibrating the paper holding plate, the piezoelectric element of the paper holding plate is fixed. A sheet conveying device, wherein a portion having a small section modulus is provided between the formed portion and a supporting point of the supporting member for supporting the sheet pressing plate. 3. A transport roller for transporting a sheet, a sheet retainer plate having a load on the surface of the transport roller and abutting against the transport roller for preventing the transport of the second and subsequent sheets, and a root portion of the sheet retainer plate. In a sheet conveying device including a support member attached to support the sheet holding plate in a cantilever manner and a piezoelectric element fixed to the sheet holding plate and vibrating the sheet holding plate, a sheet holding plate attached to the supporting member is provided. A sheet conveying device characterized in that a mounting portion is arranged at a portion corresponding to a vibration node of the sheet pressing plate.