JPH0647986A - Eliminating method for charge on print sheet - Google Patents

Abstract

PURPOSE:To destaticize a printed sheet as much as possible in the printer of an inspection apparatus arranged in a clean room. CONSTITUTION:A paper cutter 21 cutting a printing sheet 3 is earthed and an earthed conductive rod 5 for eliminating charge is provided in the contact state with the rear of the printing sheet 3. By this constitution, the erroneous operation generated in the electronic circuit of an inspection apparatus by the self-discharge of static electricity is excluded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for eliminating static electricity on a print sheet, and more particularly to a method for eliminating static electricity charged on the print sheet in a printer provided in a clean room.

[0002]

2. Description of the Related Art A semiconductor is manufactured in a clean room, and necessary inspections are performed by an inspection device provided in the clean room according to the process. The inspection data is printed and output by the printer of the inspection device. FIG. 2 shows an example of the inspection apparatus. The inspection apparatus 1 is installed on the floor F of a clean room, and the housing 2 has a printer 2 built therein. Although a continuous sheet is used as the paper for the printer 2, dust is strictly prohibited and a clean atmosphere is maintained in the clean room, whereas ordinary paper cannot be used because it generates a lot of dust. For this reason, a continuous sheet for a clean room (hereinafter, simply referred to as a clean sheet) that generates very little dust or does not generate dust at all is used. A printed sheet 3 on which the inspection data is printed (simply referred to as a print sheet) passes through the lower side of the paper cutter 21, is fed to the outside, is deposited on the floor F, and is cut by the paper cutter 21 whenever necessary.

[0003]

The above-mentioned clean sheet, which is mainly made of plastics, has a large insulation resistance and is easily charged, and the print sheet 3 is charged to a considerably high static voltage during printing or the like. . When the static voltage exceeds a certain limit, it self-discharges, and the electromagnetic field generated by the spark may affect the electronic circuit of the inspection apparatus 1 to cause a malfunction. FIG. 3 shows the method for measuring the above-mentioned electrostatic voltage. The sensor 42 of the static voltage measuring device 4 is placed at a predetermined interval D (for example, 100 mm) with respect to the print sheet 3 printed by the printer 2 and fed by the roller 22 to the outside of the housing 11.
The static voltage is directly read by the indicator of the measuring unit 41.
According to actual measurement, the print sheet 3 is charged to a high voltage of about 15,000 volts, and it has been found that this high voltage lasts for a considerably long time. Normally, the static voltage that self-discharges in air is about this level, and malfunctions that have occurred in electronic circuits due to this self-discharge have been confirmed, and countermeasures are required. The present invention has been made in view of the above, and an object of the present invention is to provide a method for removing static electricity of the above-mentioned print sheet as much as possible.

[0004]

SUMMARY OF THE INVENTION The present invention is a method for eliminating static electricity on a print sheet that achieves the above object, in which a paper cutter for cutting the print sheet fed from the printer is grounded. In addition, a conductive static elimination bar that is in contact with the back surface of the print sheet and is grounded is provided. By grounding the paper cutter and the static eliminator, static electricity on the front surface side and the back surface side of the print sheet is neutralized.

[0005]

In the above static elimination method, the static electricity on the front surface side of the print sheet fed out from the printer is neutralized by the grounding of the paper cutter, and the back surface side is statically neutralized by the grounding of the conductive static elimination stick that contacts this. It However,
Since the clean sheet has a large insulation resistance, the electric charge of the sheet does not easily move, and even if the front side and the back side are neutralized by the above method, some electric charge still remains inside the sheet. Therefore, in the above static elimination method, the static voltage does not become 0, but it has been confirmed by actual measurement that the residual static voltage becomes equal to or less than the limit value of self-discharge, so that there is no problem in practical use.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, (a) is a vertical sectional view of an inspection apparatus to which the static elimination method of the present invention is applied,
(b) is a partial perspective view of (a), and (c) is an explanatory diagram of residual voltage in static elimination.

1A and 1B, the paper cutter 21 of the printer 2 incorporated in the inspection apparatus 1 is connected to the ground E by the ground wire 23. Further, as shown in the figure, the conductive static eliminating rod 5 is attached to the support tool 51 fixed to the housing 11, and the ground wire is attached.
Ground to ground E by 52. The static elimination rod 5 is made of stainless steel or the like and does not generate dust, and its width is slightly larger than that of the print sheet 3. In FIG. 1 (c), the print sheet 3 printed by the printer 2 is
Rolled out by the roller 22. The surface of the sheet 3 touches the paper cutter 21 regardless of whether or not it is cut, so the static electricity on the surface side is discharged to the ground E, and then the back surface of the sheet 3 contacts the discharging rod 5 and the back surface side Static electricity is discharged to the ground E. However, since the print sheet 3 has high insulation as described above, there is no charge transfer inside, and even if the front side and the back side are discharged, the sheet 3
As shown in the figure, static electricity remains inside. When this was actually measured, it was about 15,000 volts before and after static elimination, but the internal residual voltage after static elimination was about 5000 volts. Since such residual voltage does not cause self-discharge, malfunctions occurring in the electronic circuit of the inspection apparatus 1 are eliminated.

[0008]

As described above, in the static elimination method according to the present invention, static electricity on the front side and the back side of the print sheet fed from the printer is eliminated by grounding the paper cutter and grounding the static eliminating rod, respectively. Things
The effect of eliminating the malfunction of the electronic circuit of the inspection device is great.

[Brief description of drawings]

1 shows an embodiment of the present invention, (a) is a vertical sectional view of an inspection apparatus to which the static elimination method of the present invention is applied, and (b) is
(a) is a partial perspective view, (c) is an explanatory diagram of residual voltage in static elimination.

FIG. 2 shows an example of an inspection device installed in a clean room.

FIG. 3 is an explanatory diagram of a method for measuring a static voltage of a clean sheet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inspection device, 11 ... Casing, 2 ... Printer, 21 ... Paper cutter, 22 ... Roller, 23 ... Ground wire, 3 ... Printed sheet, printed sheet, 4 ... Static voltage measuring device, 41 ... Measuring part, 42 ... Sensor, 5 ... Static eliminator, 51 ... Supporting tool, 52 ... Ground wire, F ... Clean room floor, E ... Grounding.

Claims (1)

[Claims] 1. In a printer provided in a clean room and using a continuous sheet for a clean room, a paper cutter for cutting a print sheet fed out from the printer is grounded, and a back surface of the print sheet contacts. A static elimination method for a print sheet, comprising a grounded conductive static elimination rod, and static electricity on the front surface side and the back surface side of the print sheet is eliminated by grounding the paper cutter and the static elimination rod.