JPH10225145A - Medium carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the friction generated between a stator and a mover, by constituting a stator carrying face of the coating layer of fluororesin material. SOLUTION: A medium carrier comprises a plate-shaped stator 1 and a mover 2, and the mover 2 is put on the stator 1, and further a medium 3 is put on it, and the stator 1 and the medium 3 are carried together by the carrying force working on the mover 2 from the stator 1. Then, for the stator 1, a plurality of strip electrodes 12 are arranged in parallel at specified intervals on a substrate 11, and thereon an insulating layer 14 is arranged, and a coating layer 14 consisting of fluororesin is provided on the insulating layer 13. Here, the base material 11 is an insulator, and the shape and the thickness can be selected freely such that it is the shape of a substrate such as glass, fiber-mixed resin, or the like, or that it is in the shape of a film or the like such as PE T, polyimide, or the like. Moreover, for the strip electrode 12, any can be used so long as it is conductive material such as gold, copper, or the like, and it is made on the substrate 11 by printing or etching. Hereby, the frictional force generated between the stator 1 and the mover 2 can be suppressed to be small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer, a facsimile, an automatic cash dispenser and the like, and a medium such as paper such as paper and bills, and cards such as cash cards and prepaid cards. The present invention relates to a medium transport device for transporting.

[0002]

2. Description of the Related Art Conventionally, copiers, printers, facsimile machines, automatic cash dispensers and the like have been disclosed in Japanese Unexamined Patent Publication No. 5-27068.
As disclosed in Japanese Unexamined Patent Publication No. 1 (1993), there has been used a transfer device that presses a rubber roller driven by a rotary electromagnetic motor against a medium such as paper sheets. However, in such a transfer device, heat generation and large power consumption of the motor itself become problems, and there is a limit to downsizing due to the configuration using the electromagnetic motor and the rubber roller. In addition, since the frictional force between the rubber roller and the transport medium is used as the force used for transporting the medium, the rubber roller itself or the rubber roller and the medium are used to obtain a stable transport force due to wear of rubber, adhesion of paper powder, and the like. It was necessary to periodically inspect and repair the pressure contact force.

In order to solve these problems, Japanese Patent Laid-Open Publication No.
There is a transfer device using an electrostatic force disclosed in 19602 and JP-A-6-56290. Such a transport device includes a stator having strip electrodes and a movable element having a resistance layer. In Japanese Patent Application Laid-Open No. Hei 5-319602, a paper to be conveyed is directly used as a moving element. In Japanese Patent Application Laid-Open No. 6-56290, a conveyed object such as paper is placed on a moving element having a high resistance value. In both cases, the electrodes of the stator are divided into three systems (three phases), which are sequentially arranged at equal intervals. For an overview of the operating principle, see
-285978 and the above-mentioned JP-A-5-3196.
As disclosed in Japanese Unexamined Patent Application Publication No. 02-206 and Japanese Unexamined Patent Application Publication No. Hei 6-56290, by applying a special combination of voltages to each phase of the stator electrode immediately before transport, positive and negative currents existing in the resistance layer of the mover can be obtained. Is electrostatically polarized. Hereinafter, this operation is referred to as an initial polarization step. When electrostatic polarization is sufficiently advanced in the movable element, when the voltage is applied to each phase of the stator electrode while switching the combination of the voltage patterns for transport, the movable element is transported by repulsion and attraction of electric charges.

[0004] However, the transfer device utilizing the electrostatic force as described above has a problem that the transfer of the moving element becomes unstable in a high humidity environment. Therefore, as a stabilization measure, Japanese Patent Laid-Open Publication No. Hei 5-191984 discloses a method in which a hole is made in a stator and air is blown out from the hole toward the mover in order to remove the mover and the stator by suction. A technique for preventing the close contact between the stator and the stator is disclosed.

In Japanese Patent Laid-Open Publication No. Hei 5-22959,
For the same purpose, there has been disclosed a technique in which a surface of a moving element or a stator is provided with irregularities to roughen a surface where the moving element and the stator come into contact, or a hole is formed in the moving element.

[0006]

However, in the method of blowing air by making holes in the stator, the number of blower pipes increases in proportion to the extension of the transport path, and the blower and external power for air compression are increased. The cost including installation is greatly increased, and at the same time, the size of the transfer device is increased. Therefore, it is difficult to differentiate the transfer device from a transfer path using a conventional electromagnetic motor. Further, if the distance between the moving element and the stator is too large, the conveyance stability is reduced. Therefore, the distance between the moving element and the stator needs to be always kept constant. For this purpose, it is necessary to control the flow rate, pressure, and the like of the air for blowing, and a control circuit, a flow rate sensor, a distance sensor, and the like are added, so that the cost increases and the product is not practical.

Also, a method of providing irregularities on the surface of the moving element or the stator is to mix the spacer material such as glass beads into the adhesive and apply it to the moving element or the stator. The degree of dispersion in the adhesive is an important factor, and the uniformity of the irregularities changes significantly. As a result, in order to obtain transport stability over the entire surface of the stator, it is necessary to uniformly control the mixing ratio and the degree of dispersion of the spacer material described above. High precision is required, accompanied by a significant increase in cost. When such a spacer material and an adhesive are applied to the moving element,
Because the weight of the mover is significantly increased, the maximum weight of the medium that can be conveyed is reduced. Even when the technique disclosed in JP-A-5-22959 was used, stable operation could not be obtained in a high humidity environment.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method in which a plurality of strip electrodes are arranged in parallel on an insulating base material. By placing a medium on the mover and switching the polarity of the voltage applied to the strip electrode in a predetermined pattern, the medium is used by utilizing the electrostatic force generated between the stator and the mover. In the medium transporting device for transporting the moving element on which the carrier is mounted, the transport surface of the stator is constituted by a coating layer of a fluororesin-based material.

[0009]

FIG. 1 is a block diagram showing a first embodiment of a medium conveying apparatus according to the present invention. FIG. 1 (a) is an overall perspective view, and FIG. 1 (b) is a side view of a stator. And a block diagram of a driving mechanism. The medium transport device according to the first embodiment includes a plate-like stator 1 and a moving member 2,
The moving element 2 is placed on the stator 1, the medium 3 is placed on the moving element 2, and the moving element 2 and the medium 3 are conveyed together by the conveying force acting on the moving element 2 from the stator 1. I do.

The stator 1 has a plurality of strip electrodes 12 arranged in parallel on a base material 11 at predetermined intervals, and an insulating layer 13
And a coating layer 14 made of a fluororesin is provided on the insulating layer 13. Hereinafter, the surface where the movable element 2 and the stator 1 are in contact is referred to as a sliding surface. The base material 11 is an insulator, and is made of a substrate such as glass, resin mixed with fiber, or the like.
The shape, thickness, etc., such as a film of T or polyimide, can be freely designed. In this embodiment mode, a resin material is used.

The strip electrode 12 can be made of any conductive material such as gold or copper, and can be formed on the substrate 11 by a known technique such as printing or etching. The strip-shaped electrode 12 is divided and connected into three phases.
Phase, called the C phase, the strip-shaped electrode connected to the A phase is 12A,
The strip electrodes connected to the B phase are indicated as 12B, and the strip electrodes connected to the C phase are indicated as 12C. After forming the strip electrode 12, an insulating layer 13 is provided thereon. In the present embodiment, the insulating coating is performed for the purpose of improving the withstand voltage and smoothing the transfer surface. The width and electrode pitch of the strip electrode 12 can be freely set. For example, the electrode pitch is 0.2 mm,
It can be set to 0.4 mm, 1.0 mm, etc., and the electrode width is also set to 0.1 mm.
It can be set to 1 mm, 0.2 mm, 0.3 mm, or the like. In the present embodiment, the electrode pitch is 0.4 mm and the electrode width is 0.1 mm.
Take a stator set to 1 mm as an example.

The insulating layer 13 is provided for inter-phase insulation of the strip electrode 12. Therefore, in addition to a resist agent used as an insulating coating on a normal substrate and a coverlay film made of PET or polyimide used for insulating a flexible substrate, it may be coated with a resin-based adhesive or a silicon adhesive. . In the present embodiment, the insulating layer 13 having a thickness of 40 μm is formed using a resist agent. In FIG. 1, the insulating layer 13 is provided only on one surface of the substrate 11, but may be provided on the entire surface of the substrate 11.

The conditions for the coating layer 14 are as follows: smoothness, low friction,
It is water repellent, moisture proof, low water absorbing, and insulating. An example of a material satisfying these is a fluororesin-based material. PTFE, FE are examples of fluororesin-based materials.
P, ETFE, PFA, PCTFE and the like. In the present embodiment, P having both a low friction coefficient, high resistance, and low water absorption is used.
TFE was used. In addition, as a coating method of the fluororesin, a known technique can be used. Further, if a PTFE adhesive tape with an adhesive applied to PTFE is used, the coat layer 14 can be easily provided. The thickness of the coat layer can be freely selected, but if it is too thick, the transport force is weakened, and the transport characteristics are deteriorated. As a result of the experiment, the distance from the upper surface of the strip-shaped electrode 12 to the surface of the stator 1 was set to 0.
When it was about 2 to 0.3 times, the conveying force became maximum. In the present embodiment, since the pitch of the strip electrode is 0.4 mm and the insulating layer 13 of 40 μm is provided on the strip electrode 12, the coating layer 14 is formed using a PTFE adhesive tape having a thickness of 40 μm. The method of providing the coat layer 14 is optional,
In consideration of moisture resistance, it is desirable to sufficiently dry the stator 1 before providing the coat layer 14.

The base of the moving element 2 is, for example, PET, polyimide, polycarbonate, polyamide, glass fiber or the like. In this embodiment, a 25 μm-thick PE
At T, the surface resistance of the surface on which the medium 3 is placed is 10 ¹¹ to 10
What was adjusted to ¹⁵ [Ω / □] was used. As a method of adjusting the surface resistance, a method of applying an antistatic agent having a weak antistatic effect or the like can be used. In addition to this, similarly to the stator, a flexible printed circuit board having electrodes therein can be used as the moving element 2. If a coat layer is also provided on the surface of the moving element 2, the transport stability is further improved.

The power supply 5 is a voltage source for applying a voltage to the strip electrode 12, and supplies a positive voltage and a negative voltage to the drive circuit 6. The drive circuit 6 can freely switch positive and negative voltages and 0 [V] (ground potential) to each of the A-phase, B-phase and C-phase of the strip-shaped electrode 12, respectively.
The polarity of the voltage applied to each phase is changed by a control signal from the control circuit 7. The drive circuit 6 includes a control circuit 7
The voltage value to be applied can be changed according to the signal from.

Hereinafter, in the present embodiment, the voltage polarity applied to each phase is represented as [A-phase polarity, B-phase polarity, C-phase polarity]. The positive polarity is represented by P, the negative polarity by N, and the ground potential by G. For example, when applying a positive polarity voltage to the A phase, a negative polarity voltage to the B phase, and a negative polarity voltage to the C phase, [P, N,
N]. The operation will be described below.

The medium transport device utilizing the electrostatic force polarizes the electric charge in the moving element 2 into a predetermined pattern, and repulses and attracts the polarity of the polarized electric charge and the polarity of the voltage applied to the strip electrode 12. Use Here, an initial polarization step of pre-polarizing the charges in the moving element 2 to be transported is required. The pattern of the voltage applied to the strip electrode 12 during the initial polarization step is called an initial polarization pattern, and the voltage pattern applied to the strip electrode 12 during transport is called a transport pattern.

FIG. 2 is an explanatory view showing the principle of movement of the moving element in the present embodiment. When the moving element 2 on which the medium 3 has arrived reaches the transport start position, under the control of the control circuit 7, the driving circuit 6 outputs an initial polarization pattern, for example, [N,
P, P] is applied to each phase of the strip electrode 12. When [N, P, P] is applied to each phase of the strip electrode 12, due to the influence of the electric charge charged in the electrode, as shown in FIG. Charges of opposite polarity accumulate. When sufficient charges are accumulated in the initial polarization pattern in the movable element 2, as shown in FIG. 2 (2), the voltage applied to the strip electrode 12 is the first stage pattern of the transport pattern [P, N, G]. , The same polarity repels and the opposite polarity attracts between the polarity of the voltage applied to the strip electrode 12 of each phase and the polarity of the electric charge polarized in the moving element 2. Due to the repulsion and attraction of the electric charges in the strip-shaped electrode 12 on the stator 1 side and the electric charges in the movable element 2, the movable element 2 and the medium 3 placed thereon start moving in the direction shown by the arrow.

When the moving element 2 moves by one pitch of the band-shaped electrode 12, the force in the conveying direction is weakened and the downward suction force is increased, and at the same time, the frictional force between the moving element 2 and the stator 1 is significantly increased. The mover 2 stops to move up. next,
As shown in FIG. 2C, the voltage applied to the strip electrode 12 is the second stage pattern of the transport pattern [G, P,
N], the moving element 2 is moved by one pitch of the electrode in the direction of the arrow and stopped by the same operation as described above. Further, although not shown, when the voltage applied to the strip-shaped electrode 12 is switched to the third stage pattern [N, G, P] of the transport pattern, the moving element 2 moves the electrode 1 pitch in the direction of the arrow by the same operation as described above. Move a minute and stop. Thereafter, the moving element 2 moves in the direction indicated by the arrow in FIG. 2 by one pitch of the strip electrode 12 by sequentially and repeatedly applying the first to third steps of the transport pattern. If the switching frequency of the three stages of the transport pattern is called a driving frequency, the moving speed of the movable element 2 can be controlled by changing the driving frequency. Speed is improved.

In such a transport system utilizing electrostatic force, it has been confirmed that the transport characteristics of the moving element 2 suddenly deteriorate or sometimes become impossible from a normal environment to a high humidity environment. It is considered that this is because if the distance between the stator and the moving element is too close, a suction force is generated between the two, and the stator and the moving element come into close contact to generate a large frictional force. It is also considered that trace water adhering to the surface of the stator and the moving element forms a bridge structure between the moving element and the stator, and the transport operation is hindered by the influence of the surface tension.

As one of the methods for adjusting the distance between the stator 1 and the moving element 2, a means for providing a spacer between them can be considered. Further, in order to reduce friction due to suction, it is preferable that the surface of the spacer has a low friction coefficient. In order to reduce the influence of surface moisture, it is preferable that the spacer surface has water repellency. Similarly, in order to improve the operation in a high humidity environment, the spacer should have low water absorption and moisture proof properties. As a material that satisfies all of these conditions, a coating of a fluororesin material represented by PTFE is considered.
As a means for easily realizing this, there is a method of attaching an adhesive tape with an adhesive to PTFE.

In view of the above, PTF obtained by attaching an adhesive to PTFE
E. An adhesive tape is applied to the insulating layer 13 of the stator 1 to form a coat layer 14, and the stator 1 having no coat layer
And a comparative experiment was performed. In this experiment, the arrival rate, which is the ratio of the designated moving distance to the actual moving distance of the moving element, was used as an evaluation criterion. When the moving element has moved the specified distance, the arrival rate is 100%. Conversely, if the mover has not moved at all, the arrival rate is 0%. The evaluation criteria for humidity used the absolute water content obtained from the room temperature and the relative humidity at that time. FIG. 3 is a graph showing the relationship between the absolute water content and the arrival rate.
E Compared to stator 1 without adhesive tape, PT
By providing the stator 1 to which the FE adhesive tape was stuck, that is, the coat layer 14, the transport characteristics of the stator 1 were remarkably improved.

As described above, according to the first embodiment of the medium transport apparatus of the present invention, the transport stability of the movable element 2 is improved by providing the fluororesin coat layer 14 on the surface of the stator 1. The properties are significantly improved. In addition, since a known simple application technique can be used for forming the coating layer 14 using a fluororesin, a special application technique and high application accuracy are not required. Furthermore, if the coating layer 14 is configured by attaching a fluororesin adhesive tape, the coating layer 14 can be formed very simply in the attaching step. In addition, since the price of the fluororesin itself is also low, it is possible to provide a medium transporting apparatus having low cost and high transport stability in addition to the simplification of the process.

FIG. 4 is a perspective view showing a second embodiment of the medium carrying device of the present invention. Since the electrical resistance and the dielectric breakdown electric field strength of the fluororesin are sufficient values as an insulating material, the insulating layer 13 can be omitted if the coat layer 14 also serves as the inter-phase insulation of the strip electrode 12. In this case, the coat layer 14 is provided directly on the stator 1 on which the strip electrodes 12 are formed. The coating layer 14 uses, for example, a PTFE coating or a PTFE adhesive tape.

When the configuration is such that the insulating layer 13 is not provided, assuming that the strip electrode pitch is 0.4 mm as described in the first embodiment, the distance from the strip electrode 12 to the stator surface is taken into consideration. Then, the thickness of the coat layer 14 is 80
It is necessary to be about μm. As described above, by omitting the insulating layer 13, the number of manufacturing steps can be reduced by one step, and also in this case, the transport stability is improved.

According to another embodiment of the present invention, a coating layer 14 is provided on the moving element 2 side in consideration of further reducing the friction coefficient on the sliding surfaces of the moving element 2 and the stator 1. The sliding surfaces of the stator 1 and the moving element 2 may both be the coat layer 14. By providing the fluororesin coating layers on both surfaces of the moving element 2 and the stator 1 in this manner, the friction coefficient is further reduced, and the transport stability is further improved.

When the coating layer 14 is provided only on the stator 1 side, not only the surface of the stator 1 but also the entire surface may be covered with the coating layer 14. By covering the whole surface of the stator 1 with the coat layer 14, the moisture-proof effect is further enhanced. Further, when the coating layer 14 is provided on the movable element, the entire surface of the movable element 1 is not limited to the sliding surface,
By covering with, the effect of the moisture-proof property becomes higher.

As described above, according to the present invention, as in the prior art, a special spacer is dispersed in a resin at a highly controlled weight ratio and with high precision, and is fixed with high uniformity. There is no need to coat the rotor, no complicated control units such as air pressure control and air flow control, and many detection devices such as position detection sensors and flow sensors are not required. Therefore, the medium conveyance device of the present invention has a very small increase in cost regardless of the length of the conveyance path, and has no effect on the product competitiveness.

In addition, since the fluororesin tape has a very high flexibility, if a flexible substrate is used as the stator 1, even if the fluororesin tape is stuck on the entire surface of the stator 1, the flexibility of the stator 1 can be improved. , And it is possible to form a curved conveyance path having a curved portion. On the other hand, when the stator is coated with a resin in which a special spacer material is dispersed as in the related art, a curved path cannot be formed because the flexibility of the stator is impaired.

Further, in the present invention, when the stator 1 is provided with a coat layer, there is no increase in the weight of the moving member, so that the maximum transport speed does not decrease. Furthermore, even when a coat layer is provided on the moving element 2, the weight of the coat layer is extremely small compared to the weight of the moving element, so that the influence on the transfer characteristics is very small, and high transfer stability can be obtained. No problem at all.

Also, since fluororesin has high moisture-proof properties,
By coating the stator 1 and the mover 2,
It is possible to prevent the stator 1 and the moving element 2 from being impregnated with water, and it is possible to greatly delay the influence of the water impregnation on the transport characteristics. In the description of the medium transport device of the present invention, in each embodiment, a movable element having a predetermined resistance value is used, but if the resistance value of the transported medium is sufficiently high,
It is also possible to carry the medium 3 directly on the stator 1 without using a moving element.

Also in this case, by providing a coating layer 14 made of a fluororesin on the surface of the stator 1, high transport stability can be obtained. Further, even in the case of a device that has an electrode inside as the movable element 2 like the stator 1 and applies a voltage to this voltage to create an initial polarization state,
Sliding surface of stator 1 or sliding surface of moving member 2;
Further, by providing the coating layer 14 made of a fluororesin on both sliding surfaces, high transport stability can be obtained.

[0033]

As described above, according to the present invention, in the medium conveying device utilizing electrostatic force, the conveying surface of the stator is constituted by the coating layer of the fluororesin-based material. Depending on the thickness, the distance between the strip-shaped electrode and the movable element can be optimized, the frictional force generated between the stator and the movable element can be reduced, and furthermore, the water impregnation on the transfer surface can be prevented. Therefore, high transport stability can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a medium transport device of the present invention.

FIG. 2 is an explanatory view showing a moving principle of a moving element.

FIG. 3 is a graph showing a relationship between an absolute water content and an arrival rate.

FIG. 4 is a perspective view showing a second embodiment of the medium transport device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Moving element 12 Strip electrode 14 Coat layer

Claims (6)

[Claims] 1. A moving element is placed on a transfer surface of a stator having a plurality of strip electrodes arranged in parallel on an insulating base material,
By switching the polarity of the voltage applied to the band-shaped electrode in a predetermined pattern, utilizing a static force generated between the stator and the movable element, a medium transporting apparatus for transporting the movable element includes: A medium transport device, wherein a transport surface of the child is formed of a coat layer of a fluororesin-based material. 2. The medium transport apparatus according to claim 1, wherein the medium to be transported is placed on the movable element, and the medium is loaded by utilizing an electrostatic force generated between the stator and the movable element. A medium transport device for transporting a child. 3. The medium transport apparatus according to claim 1, wherein a medium to be transported is used as the movable element, and the medium is directly transported by utilizing an electrostatic force generated between the stator and the medium. A medium transport device characterized by performing the following. 4. The medium transporting device according to claim 2, wherein a coating layer made of a fluororesin-based material is provided on a surface of the movable member that contacts the transporting surface of the stator. 5. The medium transport device according to claim 1, wherein the coat layer is formed by sticking an adhesive tape whose surface is formed of a fluororesin-based material. Transport device. 6. The medium transport apparatus according to claim 1, wherein the coat layer is formed by applying a fluororesin-based material.