JPH07125865A - Electrostatic attraction belt conveyor - Google Patents

Abstract

PURPOSE:To obtain an electrostatic attraction belt conveyor which possesses the strong attraction force for a transferred article by forming an electrode film consisting of an electric conductive material on one surface of an endless belt made of insulating material and forming an electric charge supply part for applying each electric charge having the reverse polarity to the surface of the belt and the surface of the electrode film. CONSTITUTION:When a driving roller 2 is revolutionarily driven, and an electric charge supply part 7 applies the dc voltage of 500-2,000V between the surface of a belt 4 and the surface of an electrode film 6, the surface of the belt 4 is charged to the positive polarity (+) and the surface of the electrode film 6 is charged to the negative polarity (-). Also at the belt part separated from the electric charge supply part 7, a residual attracted state is generated, and if a paper sheet 5 as a transferred article is placed on an electrostatic attractive belt conveyor 1, an electrostatic attractive force is generated on the paper sheet 5 through the surface of the belt 4, and the paper sheet 5 is attracted to the surface of the belt 4, and the paper sheet 5 is transferred in this state to a driven roller 3 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic adsorption belt conveyor for adsorbing an object to be conveyed on the surface of a belt by electrostatic attraction and conveying the same.

[0002]

2. Description of the Related Art Conventionally, as a conveying means for conveying an object to be conveyed such as a paper sheet in a sheet discharging section of a printing machine or a transfer section in a copying machine, the object to be conveyed is sucked by a vacuum pad and conveyed. It is known that the transported object is caught by the dog of the chain and transported, and the transported object is sandwiched between a pair of upper and lower belts and transported.

However, since all of these conventional conveying means are constructed so that the conveying means is brought into contact with an object to be conveyed, the image is adversely affected by printing ink or toner on the surface of the object. However, there is a problem in that it may affect the product, or the device configuration may become complicated, resulting in an unavoidable increase in cost.

Therefore, in recent years, a so-called electrostatic adsorption belt conveyor has been widely used in which an object to be conveyed is adsorbed on the surface of the belt by electrostatic attraction and conveyed. According to this electrostatic adsorption belt conveyor, the transported object can be transported without contacting the surface of the transported object, and the adverse effect on the image formed on the surface of the transported object can be eliminated. At the same time, the device structure can be simplified and the device can be manufactured at low cost.

An example of a conventionally used electrostatic attraction belt conveyor will be described with reference to FIG. As shown in the figure, in a conventional electrostatic adsorption belt conveyor, a belt (adsorption layer) 21 made of a dielectric material and electrodes 22 arranged in a comb pattern so as to be in sliding contact with the lower surface of the belt 21.
And a pair of metal rollers 23 arranged below the electrodes 22 and a DC power source 24 for applying a voltage to the electrodes 22 via the rollers 23, and an insulating protective layer 25 is provided on the lower surface of the electrodes 22. Is provided. With such a configuration, when a voltage is applied to the electrode 22 from the DC power supply 24, an object to be attracted such as a paper sheet placed on the belt 21 due to the electrostatic attraction force is applied to the belt 21. It is suction-held and conveyed to a predetermined position.

[0006]

However, in the above-described conventional electrostatic attraction belt conveyor, the belt as the attraction layer is made of a dielectric material and the electrodes are arranged on the back side of the belt in a comb-shaped pattern, for example. Therefore, it is difficult to apply a high voltage between the positive and negative electrodes in consideration of the insulation between the positive and negative electrodes, which makes it difficult to obtain a strong attraction force for the transported object. There was a point.

The present invention has been made in view of these problems, and in a belt conveyor using electrostatic attraction,
The purpose of the present invention is to improve the suction force for the transported object.

[0008]

In order to achieve the above-mentioned object, an electrostatic attraction belt conveyor according to the present invention has an electrode film made of a conductive material formed on one surface of an endless belt made of an insulating material. At the same time, it is characterized in that the surface of the belt and the surface of the electrode film are provided with a charge supply section for supplying charges of opposite polarities to each other.

[0009]

When the object to be conveyed is placed on the belt conveyer, the electric charge is applied to the surface of the belt and the surface of the electrode film by the electric charge supplying section, so that an electric field is accumulated on the surface of the belt. As a result, an electrostatic attraction force is generated on the belt, and even the belt portion away from the charge supply unit is in a residual attraction state, so that the transported object is transported while being attracted to the surface of the belt. In this case, since the belt is made of an insulating material and electric charges of opposite polarities are applied to the surface of the belt and the surface of the electrode film respectively, even if the thickness of the belt is reduced, high voltage is applied. It is possible to withstand the application and it is possible to adsorb the transported object with a strong adsorption force.

It is preferable that the electrode film is arranged in a plurality of parts separately along the moving direction of the belt.

In that case, it is preferable that an electrode film is provided on the back surface side of the transport surface and a negative charge is applied to the electrode film.

Further, when a reverse polarity charge supplying portion for supplying a charge having a polarity opposite to that of the charge supplying portion to the belt and the electrode film is provided, the polarity of the belt surface is reversed by the reverse polarity charge supplying portion. As a result, it is possible to prevent the attraction force from decreasing due to the electret phenomenon of the belt, and to always secure a strong attraction force for the transported object.

The belt is preferably made of a resin having a volume resistivity of 10 ¹³ Ωcm or more.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the electrostatic attraction belt conveyor according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an electrostatic attraction belt conveyor according to an embodiment of the present invention. As shown in the figure, the electrostatic attraction belt conveyor 1 of this embodiment has a driving roller 2 and a driven roller 3 which are arranged in parallel with each other at a predetermined interval, and an endless type which is suspended between these rollers 2 and 3. Belt 4 of. A paper sheet 5, which is an object to be conveyed, is placed on the upper surface of the belt 4, and the paper sheet 5 is moved forward by the rotation of the drive roller 2 in the direction of the arrow (rightward in the figure).
Is transported to.

As shown in FIGS. 2 and 3, on the back surface of the belt 4, rectangular (square in the illustrated example) electrode films 6 are arranged at predetermined intervals along the transport direction. It is stacked. Further, roller guides 4a are formed on both sides of the electrode film 6 provided on the back surface of the belt 4 so as to avoid the pressing force of the driving roller 2 or the driven roller 3 against the electrode film 6.

The belt 4 is made of an insulating resin having a thickness of about 30 to 200 μm and a volume resistivity of 10 ¹³ Ωcm or more, and has bending elastic modulus, abrasion resistance, tensile strength, and the like, a roller diameter, and an object to be conveyed. An appropriate material is selected in consideration of the conditions such as the weight, transport speed, tension applied to the belt, and durability time. Preferable examples of the material forming the belt 4 include polyester, polyacetal, polypropylene, vinyl chloride, polycarbonate, urethane, and fluorine-based film. Also, in consideration of the fact that the adsorption force tends to differ depending on temperature conditions and humidity conditions, it is possible to use a composite film formed by laminating resin such as polyester, vinyl chloride, styrene, and polyethylene having low water absorption on the surface, By doing so, it becomes possible to obtain a more stable adsorption force.

The electrode film 6 is formed by depositing a conductive metal such as aluminum, copper, nickel or silver on the surface of the belt 4 made of an insulating resin as described above, or by adhering it with an adhesive. It is formed. In that case, the thickness of the electrode film 6 is set to about 0.1 to 50 μm, and an appropriate thickness is selected according to durability and load voltage. For example, in order to obtain one that can withstand use of 500,000 to 1,000,000 rotations, a belt made of polyester resin has a thickness of 1
It is preferable to select a rolled copper foil having a thickness of 0 to 30 μm, which is subjected to an adhesion process. Alternatively, a carbon-based inorganic material may be dispersed in a resin binder, coated on the surface of a belt made of a fluororesin, and then baked at 250 to 300 ° C. to be selected.

Further, since positive and negative charges are alternately applied to the adjacent electrode films 6 and 6, as will be described later, it is better to narrow the interval between the electrode films 6 and 6. Although a strong attracting force can be obtained, there is a case where a short circuit occurs depending on the voltage applied from the charge supplying brushes 8, 9; 13, 14 described later and the temperature and humidity conditions during use. The distance between 6 is 3 to 10 mm, preferably 5 to 7 mm.

In the belt conveyer 1 having the above-described structure, as shown in FIG. 2, the charge supplying section 7 is arranged slightly upstream of the driving roller 2 in the belt moving direction. The charge supply unit 7 includes charge supply brushes 8 and 9 that contact the surface of the belt 4 and the surface of the electrode film 6, respectively.
And a DC power source 10 for applying a voltage of 500 to 2000 V to the belt 4 and the electrode film 6 via the charge supply brushes 8 and 9.
The surface of the electrode is charged with positive (+) charges, and the surface of the electrode film 6 is charged with negative (-) charges.

A reverse polarity charge supply unit 11 is arranged upstream of the charge supply unit 7 in the belt moving direction. The reverse polarity charge supply section 11 has a structure similar to that of the charge supply section 7, but supplies a charge having a reverse polarity to the charge supply section 7 to the belt 4 and the electrode film 6, respectively. That is, 500 to 2000V by the DC power supply 12
When the voltage is applied, the surface of the belt 4 is charged with a negative (−) charge through the charge supply brushes 13 and 14, and the surface of the electrode film 6 is charged with a positive (+) charge. To be done.

In the electrostatic attraction belt conveyor 1 having such a structure, the driving roller 2 is rotationally driven, and in the charge supplying section 7, the voltage of 500 to 2000 V is applied between the surface of the belt 4 and the surface of the electrode film 6 in the charge supplying section 7. When a DC voltage is applied, the surface of the belt 4 is charged with positive (+) charges, and the surface of the electrode film 6 is charged with negative (−) charges.

Further, since the residual adsorption state is obtained even in the belt portion distant from the electric charge supplying section 7, when the paper sheet 5 as the conveyed object (adsorbed object) is placed on the electrostatic adsorption belt conveyor 1, the belt is moved. An electrostatic attraction force is generated on the paper sheet 5 through the surface of the paper sheet 4, the paper sheet 5 is attracted to the surface of the belt 4, and in this state, the paper sheet 5 is conveyed to the driven roller 3 side. When the belt 4 comes to the position of the driven roller 3 in this way, the paper sheet 5 on the belt 4 is discharged to a stack or other transfer means provided in the front by a separator (not shown) arranged in the vicinity of the driven roller 3.

After the paper sheet 5 is discharged, when the belt 4 reaches the position of the opposite polarity charge supplying section 11, the opposite polarity charge supplying section 11 forms the charge supplying section on the surface of the belt 4 and the surface of the electrode film 6. Charges having a polarity opposite to that of 7 are applied, whereby the polarities of the charges of the belt 4 and the electrode film 6 are switched. In this way, the charge supply unit 7
By alternately switching the polarities of the electric charges of the belt 4 and the electrode film 6 between and and the opposite polarity charge supply unit 11, it is possible to prevent the belt 4 from being in an electret state, and thereby the next new paper It becomes possible to generate a strong suction force on the surface of the belt 4 when the sheet 5 is conveyed.

The charge supplying brushes 8, 9; 13, 14 used in this embodiment are preferably made of a conductive resin or metal and have good wear resistance. Further, when long-term durability is required, it is desirable to use a conductive roller instead of the brush and apply the electric charge by rotating the roller. Even in that case, it is preferable to use a roller made of a metal such as copper, aluminum or iron or a conductive resin.

The electrostatic attraction belt conveyor 1 of this embodiment is
It is preferably used as a sheet conveying means between a transfer device and a fixing device in a copying machine. When applied to a copying machine in this way, since the surface of the belt 4 is positively charged, the toner image that is negatively charged and adheres to the sheet is adsorbed and the toner on the sheet is absorbed. The amount of adhesion can be increased, an image with high solid density, which is important in a copying machine, can be obtained, and transfer efficiency can be improved. Further, by positively charging the surface of the belt in this way, it is possible to reduce the transfer voltage when transferring the toner to the paper, and further, a device for removing ozone generated by corona discharge is unnecessary. Therefore, the device can be manufactured at low cost.

Further, according to the present embodiment, since the charge polarities of the belt 4 and the electrode film 6 can be automatically changed, a special changeover switch and a large-scale power supply device are unnecessary, and the device can be downsized. It can be manufactured at low cost.

Further, since the dielectric film generally used as a conventional belt material has a low insulation property, it is necessary to have a predetermined thickness or more. According to this embodiment, for example, the dielectric breakdown strength is 10 to 10. By using the insulating film of 30 KV / mm or more, even if the thickness of the belt 4 is reduced, it is possible to withstand the application of a high voltage, so that the adsorption force can be increased.

[0029]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the belt material can be selected from general insulating materials, and the selection range is wide, and the material suitable for the use environment and the belt are connected. Materials suitable for processing conditions such as ultrasonic welding and heat welding can be obtained at low cost. Further, since the insulating material is used, it is possible to withstand the application of high voltage even if the thickness of the belt is reduced, and it is possible to obtain a strong adsorption force.

[Brief description of drawings]

FIG. 1 is a perspective view showing an electrostatic attraction belt conveyor according to an embodiment of the present invention in a paper sheet transporting state.

FIG. 2 is an explanatory view of a main configuration of an electrostatic attraction belt conveyor according to an embodiment of the present invention.

FIG. 3 is a back view (a) of the electrostatic attraction belt conveyor according to the embodiment of the present invention and a sectional view (b) taken along the line AA thereof.

FIG. 4 is a sectional view showing an example of a conventional electrostatic adsorption belt conveyor.

[Explanation of symbols]

 1 Electrostatic Adsorption Belt Conveyor 2 Drive Roller 3 Driven Roller 4 Belt 6 Electrode Film 7 Charge Supply Part 11 Reverse Charge Charge Supply Part 8, 9; 13, 14 Charge Supply Brush

Claims (5)

[Claims] 1. An electric charge supply for forming an electrode film made of a conductive material on one surface of an endless belt made of an insulating material and giving electric charges of opposite polarities to the surface of the belt and the surface of the electrode film, respectively. An electrostatic adsorption belt conveyor having a section. 2. The electrostatic adsorption belt conveyor according to claim 1, wherein the electrode film is arranged in a plurality of parts separately along a moving direction of the belt. 3. The electrode film is provided on the back surface side of the transport surface, and a negative charge is applied to the electrode film.
The electrostatic attraction belt conveyor according to. 4. The electrostatic attraction belt conveyor according to claim 3, further comprising a reverse polarity charge supply unit that supplies a charge having a polarity opposite to that of the charge supply unit to the belt and the electrode film, respectively. 5. The electrostatic adsorption belt conveyor according to claim 1, wherein the belt is made of a resin having a volume resistivity of 10 ¹³ Ωcm or more.