JP4800113B2 - Printing apparatus and printing method - Google Patents

Description

  The present invention relates to a technical field of a printing apparatus and a printing method.

  2. Description of the Related Art Conventionally, printing apparatuses (inkjet printers) that eject ink droplets from a nozzle onto a printing object have been widely used.

  Since such a printing apparatus can form a film having a desired shape without requiring a lithography process by causing ink droplets to land at a desired position, in recent years, an organic semiconductor film or an organic light-emitting film It is used in various fields such as film formation.

  However, in the above printing method, when the printing object is charged or the surface potential of the printing object varies, the Coulomb force acts on the ink droplets, and the landing position of the droplets deviates, and the film formation position There is a problem in that the accuracy of the shape is reduced.

In particular, when printing is performed in a dry gas atmosphere in which the air is exhausted and a clean dry gas (for example, dry nitrogen gas) is supplied in order to prevent ink deterioration, the printed object is insulating like a glass substrate. In the case of a substrate, the insulating substrate is charged as much as several KV not only when being transported in the atmosphere but also being left in the atmosphere.
JP-A-8-55693 JP-A-5-31998

  The present invention solves the above-described problems, and an object of the present invention is to increase the printing accuracy by removing electricity from a printing object.

In order to solve the above-mentioned problems, a first aspect of the present invention provides a mounting table on which a printing object can be mounted, a printing head that is provided with a plurality of nozzles and can eject ink from the nozzles, and emits X-rays. The print head has a nozzle directed to the mounting table, and the ink ejected from the nozzle is applied to the surface of the printing object on the mounting table. The X-ray generation source is disposed above the mounting table, and is configured to irradiate the surface of the printing object on the mounting table with the X-rays, and is disposed on the mounting table. The printing object is a printing apparatus configured to be neutralized by being irradiated with the X-rays , and the printing head includes the printing head on a front side and a rear side in a moving direction of the printing head. Surface potential sensor that measures the surface potential of an object The print head and the surface potential sensor are configured to reciprocate together relative to the print object on the mounting table, and when the print head moves, one of the surfaces A potential sensor is configured to move on the printing object prior to the print head and to discharge the ink while performing measurement. The surface potential sensor is connected to a control system, and the surface potential is When the measured value of the sensor exceeds a set value, the ink ejection is stopped, and the print head and the surface potential sensor are placed on the print object when the X-ray is irradiated. This is a printing apparatus configured to be retracted to a position where no X-ray shadow occurs.
The invention described in claim 2 includes a mounting table on which a printing object can be mounted, a print head provided with a plurality of nozzles and capable of ejecting ink from the nozzles, and an ionizer that discharges ionized gas. The printing head is arranged on the mounting table, and the ink ejected from the nozzle is configured to be applied to the surface of the printing object on the mounting table, and the ionizer is on the mounting table. wherein arranged in the printing surface of the object in a position to blow the ionized gas, in the configuration printing device as is the printing object placed on the mounting table are neutralizing are blown gas having the ionization The print head is provided with surface potential sensors for measuring the surface potential of the print object on the front side and the rear side in the moving direction of the print head, and the print head and the surface The potential sensor is configured to reciprocate together relative to the print object on the mounting table, and when the print head moves, one of the surface potential sensors is more than the print head. It is configured so that the ink can be ejected while moving on the printing object first and measuring.
The surface potential sensor is connected to a control system, and is configured to stop the ejection of the ink when a measured value of the surface potential sensor exceeds a set value. The print head and the surface potential sensor are When the gas is blown, the printing apparatus is configured to be able to retreat to a position where the ionized gas does not hit the nozzle .
According to a third aspect of the present invention, there is provided a mounting table on which a printing object can be mounted, a plurality of nozzles, a print head capable of ejecting ink from the nozzles, and an X-ray generation source that emits X-rays. And the print head is arranged on the mounting table, the ink ejected from the nozzle is applied to the surface of the printing object on the mounting table, and the X-ray generation source A printing apparatus that is arranged above the printing table and configured to irradiate the surface of the printing object on the printing table with the X-rays is used. The printing head has a moving direction of the printing head. A surface potential sensor for measuring the surface potential of the print object is disposed on the front side and the rear side, and the print head and the surface potential sensor are relative to the print object on the mounting table. Reciprocally move together to When the ink is moved, one of the surface potential sensors is moved on the print object before the print head, and the portion of the print object before the ink is landed. When the surface potential is measured by the surface potential sensor, the ink is ejected, and when the measured value of the surface potential sensor exceeds a set value, the ejection of the ink is stopped, and the print head and the surface potential sensor are In the printing method, when the X-ray is irradiated, the X-ray is retreated to a position where no shadow of the X-ray is generated on the print object, and the print object is irradiated with the X-ray to remove static electricity.
The invention according to claim 4 includes a mounting table on which a printing object can be mounted, a print head provided with a plurality of nozzles and capable of ejecting ink from the nozzles, and an ionizer that discharges ionized gas. The printing head is arranged on the mounting table, and the ink ejected from the nozzle is configured to be applied to the surface of the printing object on the mounting table, and the ionizer is on the mounting table. The printing object is arranged at a position where the ionized gas is blown onto the surface of the printing object, and the printing object arranged on the mounting table uses a printing apparatus configured to be discharged by blowing the ionized gas. The print head includes a surface potential sensor for measuring a surface potential of the print object on the front side and the rear side in the moving direction of the print head, and the print head and the surface. The position sensor reciprocally moves together relative to the print object on the mounting table, and when the print head moves, one of the surface potential sensors comes before the print head. The ink is ejected while the surface potential of the printing object is measured by the surface potential sensor before the ink is landed, and the surface potential sensor is measured. When the value exceeds a set value, the ejection of the ink is stopped, and the print head and the surface potential sensor are retracted to a position where the ionized gas does not hit the nozzle when the ionized gas is sprayed. The printing method of discharging electricity by spraying the ionized gas onto the printing object.

The present invention is configured as described above, and the printing apparatus of the present invention has a static elimination means such as an X-ray generation source or an ionizer.
When the static elimination means is an X-ray generation source, it is preferable to arrange the printing apparatus inside a printing chamber having X-ray shielding properties so that X-rays do not leak around the printing apparatus.

  An ink used for forming an organic semiconductor film or an organic light emitting film contains an organic material that easily deteriorates with water or oxygen, such as an organic semiconductor material or an organic light emitting material. When ink contains substances that easily deteriorate due to water or oxygen, a printing device is installed in a printing chamber with an airtight ceiling and walls to block it from the atmosphere, and a dry atmosphere in which oxygen and moisture are removed from the printing chamber It is desirable to form the ink and apply the ink in the dry atmosphere.

According to the present invention, since the surface potential of the surface of the printing object can be measured before the ink is applied to the surface of the printing object, the ink is ejected while measuring the surface potential, and the absolute value of the surface potential is measured. When the value exceeds the set value, the ejection of ink can be stopped by a signal sent from the control system.
Next, the head holder can be moved to the retracted position so that X-ray shadows do not occur on the print target, and the X-rays can be irradiated for a predetermined time to perform static elimination.
If the print head is retracted to the retracted position so that the nozzle does not hit the ionizer gas, the meniscus in the nozzle can be neutralized without being disturbed by the gas.

Reference numeral 1 in FIG. 1 shows an example of the printing apparatus 1 of the present invention, and the printing apparatus 1 is disposed in the printing chamber 2.
The printing apparatus 1 has a mounting table 20 disposed on the bottom wall of the printing chamber 2, and head holders 23 a and 23 b are disposed on the mounting table 20. FIG. 2 is a schematic plan view showing the positional relationship between the mounting table 20 and the head holders 23a and 23b. Guide rails 21 ₁ and 21 ₂ extending on the mounting table 20 in the X-axis direction and the Y-axis direction, respectively. , 22 _{1 to} 22 ₄ are arranged.

The guide rails 22 _{1 to} 22 ₄ in the X-axis direction are attached to the guide rails 21 ₁ and 21 ₂ in the Y-axis direction so as to be movable along the guide rails 21 ₁ and 21 ₂ , and the head holders 23a and 23b are mounted in the X-axis direction. The guide rails 22 _{1 to} 22 ₄ are attached so as to be movable along the guide rails 22 _{1 to} 22 ₄ . When the guide rails 22 _{1 to} 22 ₄ in the X-axis direction are moved and the distance between them is changed, the angle formed by the head holding bodies 23a and 23b with the X-axis and the Y-axis changes.

  A plurality of print heads 15a and 15b are attached to the head holders 23a and 23b, respectively. Here, there are two head holders 23a and 23b, and a plurality of print heads 15a and 15b are attached in a staggered manner, but the present invention is not limited thereto.

The head holders 23a and 23b are arranged so that the print heads 15a and 15b are positioned higher than the printing object 5 arranged on the mounting table 20, and therefore the head holders 23a and 23b are arranged as X. If the print heads 15 a and 15 b are moved along the axial guide rails 22 _{1 to} 22 ₄ , the print heads 15 a and 15 b can be passed over the print object 5 without contacting the print object 5.

Each of the print heads 15a and 15b is provided with a plurality of nozzles 16a and 16b, and the ink supplied from the ink supply system 19 to the print heads 15a and 15b is ejected from the nozzles 16a and 16b.
Although the interval between the adjacent nozzles 16a and 16b is constant, when the ink is landed at a predetermined printing position, the head holders 23a and 23b are arranged in the X axis and Y direction even if the interval between the printing positions is different from the nozzle interval. If the angle formed with the axis is changed, the interval between the nozzles 16a and 16b with respect to the X-axis direction and the Y-axis direction of the print object 5 can be changed. For example, the interval between the nozzles 16a and 16b in the Y-axis direction When the print position is adapted and moved in the X-axis direction, ink can be landed on each print position.

Next, a printing method for applying ink to the surface of the printing object 5 using the printing apparatus 1 will be described.
An exhaust system 9 and a gas supply system 8 are connected to the printing chamber 2. The exhaust system 9 is operated to discharge the gas inside the printing chamber 2 to the outside, and the gas supply system 8 is operated to perform printing. A drying gas is supplied into the chamber 2 to form a dry atmosphere inside the printing chamber 2.

  A carry-in / out port (not shown) is provided on the side wall of the printing chamber 2, and a transport device (not shown) is connected to the carry-in / out port in an airtight manner while maintaining a dry atmosphere inside the printing chamber 2. A printing object is accommodated in the transport device, and the printing object is carried into the printing chamber 2 from the carry-in / out opening and placed on the mounting table 20.

  Referring to FIG. 3, a printing object 5 is, for example, an in-process product of an organic EL element, and includes a substrate 51, a transparent electrode film 52 disposed on the substrate 51, and an insulation disposed on the transparent electrode film 52. Layer 56.

  A plurality of openings 55 are formed in the insulating layer 56, the transparent electrode film 52 is exposed on the bottom surface of the opening 55, and the insulating layer 56 is exposed on the surface outside the opening 55. For example, the insulating layer 56 is a material such as silicon dioxide. The inside of the printing chamber 2 is maintained in a dry atmosphere, and the printing object 5 with the insulating layer 56 exposed on the surface is charged when being carried in or placed on the mounting table 20.

  An X-ray generation source 40 is arranged at a position outside the moving range of the head holders 23a and 23b in the printing chamber 2. The X-ray generation source 40 is located at a position higher than the mounting table 20 with the X-ray emission window facing the mounting table 20, and the head holders 23 a and 23 b are placed above the printing object 5. If the X-ray is emitted from the X-ray generation source 40 by moving to a retreat position that is outside of the X-ray shadow on the surface of the print object 5, X-rays are irradiated to the vicinity of the surface of the print object 5. The

When X-rays are irradiated, gas (here, dry gas) is ionized on the printing object 5, + ions and − ions are generated, the charge of the printing object 5 is neutralized, and the charge is eliminated.
X-ray irradiation is performed for a predetermined time, and the head holders 23 a and 23 b are returned from the retracted position onto the print object 5.

  In this printing object, each opening 55 is a printing position where ink is landed, and the interval between the nozzles 16a and 16b is adapted to the interval between the openings 55, and ink is ejected toward the opening 55 while moving in the X-axis direction. To do.

  Since the printing object 5 is neutralized, the ink is not affected by the electrostatic force, and is accurately landed on the bottom surface of the opening 55, and an organic layer is formed in the opening 55. The ink may be ejected while moving the head holders 23a and 23b, or after the head holders 23a and 23b are stopped at a position where the nozzles 16a and 16b are located directly above the opening 55. Also good.

  When ink is applied in each opening 55 and printing is finished, the printing object 5 is lifted from the mounting table 20 and returned to the transport device from the carry-in / out entrance. The ink contains an organic material such as an organic light emitting material or an organic semiconductor material, and these organic materials are likely to be chemically deteriorated by oxygen or moisture, but from the step of carrying in the printing object 5, If the dry atmosphere in the printing chamber 2 is maintained until the step of returning to the conveying device after the printing is completed, the organic material in the ink does not deteriorate during ejection or after application.

  In the above, the case of performing static elimination before starting printing has been described. However, the present invention is not limited to this, and printing is performed while measuring the surface potential of the printing object 5, and static elimination is performed as necessary. May be performed.

Specifically, as shown in FIGS. 1 and 2, the surface potential sensor 7 is attached to the head holders 23a and 23b.
Here, the surface potential sensor 7 of one head holding body 23a, the print head 15a of the head holding body 23a, the print head 15b of the other head holding body 23b, and the surface potential sensor 7b of the head holding body 23b are: They are arranged in the order described along the X-axis direction. Accordingly, the surface potential sensors 7a and 7b are located on both sides of the movement direction of the print heads 15a and 15b, and the head holders 23a and 23b move forward in the X axis direction and return in the X axis direction. The surface potential sensors 7a and 7b move on the print object 5 before the print heads 15a and 15b. Therefore, it is possible to measure the surface potential of the printing object 5 before the ink is landed.

  A control system 29 is disposed outside the printing chamber 2. Each of the surface potential sensors 7a and 7b is connected to a control system 29. When ink is ejected while measuring the surface potential of the printing object 5, and the absolute value of the surface potential exceeds a set value, the control system 29 Ink ejection is stopped by a signal to be sent, the head holders 23a and 23b are moved to the retracted position, the X-ray shadow is not generated on the print target 5, and X-rays are irradiated for a predetermined time to perform static elimination. .

  If neutralization is performed while measuring the surface potential, the neutralization can be terminated if the X-ray irradiation is stopped when the absolute value of the surface potential is equal to or lower than the set value. After completion of static elimination, the head holders 23a and 23b are returned from the retracted position onto the print target 5, and printing is resumed.

Although the above has described the case of performing static elimination by irradiating with X-rays, the present invention is not limited to this.
Reference numeral 3 in FIG. 5 shows another example of the printing apparatus of the present invention. This printing apparatus 3 has an ionizer 30 instead of the X-ray generation source 40 of the printing apparatus 1 shown in FIG.

The ionizer 30 has a gas supply source 31, an ionization means 32 connected to the gas supply source 31, and a jet 33 connected to the ionization means 32. When the valve of the gas supply source 31 is opened, the ionization means Gas is ejected from the ejection port 33 through the gas outlet 32. At this time, when the ionization means 32 is energized and discharge occurs in the ionization means 32, the gas flowing through the ionization means 32 is ionized. , And ejected from the ejection port 33.

The gas supply source 31 and the ionization means 32 are provided outside the printing chamber 2, and the ejection port 33 is attached to a position higher than the mounting table 20 on the inner wall of the printing chamber 2.
The ejection port 33 is directed to the surface of the printing object 5 disposed on the mounting table 20, and a gas containing ions is blown onto the surface of the printing object 5, and the printing object 5 is discharged. At this time, if the print heads 15a and 15b are retracted to the retracted position so that the nozzles 16a and 16b do not hit the gas, the meniscus in the nozzles 16a and 16b will not be disturbed by the gas.

<Experimental example 1>
Dry nitrogen as a dry gas was supplied while exhausting the inside of the printing chamber 2 to form a dry atmosphere. After leaving the glass substrate in this dry atmosphere for 10 hours, the surface potential was measured. The measurement results are shown on the left side of the graph of FIG. After the surface potential measurement, the ionizer 30 was energized, a gas containing ions was sprayed onto the glass substrate surface, and the surface potential of the glass substrate after charge removal was measured. The measurement results are shown together with the value of the surface potential on the right side of the graph of FIG.
As is clear from FIG. 6, the surface potential of the glass substrate before static elimination was about 2 KV, whereas the surface potential was below 100 V after static elimination.

<Experimental example 2>
After measuring the surface potential before and after neutralization, the neutralized glass substrate was conveyed inside the printing chamber 2 where the dry atmosphere was maintained, and the surface potential after conveyance was measured. The glass substrate after conveyance was neutralized, and the surface potential of the glass substrate after neutralization was measured.

  From the left side of the graph of FIG. 7, the surface potential of the substrate before transport and before neutralization, the surface potential of the substrate before transport and after neutralization, the surface potential of the substrate after transport and before neutralization, The surface potential of the substrate after the transfer and after the charge removal is shown. Regarding the substrate after neutralization (with neutralization), the numerical value of the surface potential is also described below the graph of FIG.

  As is clear from FIG. 7, when the glass substrate is transported in a dry atmosphere, the surface potential rises again to about 1 to 1.6 KV. However, when the glass substrate after transport is neutralized, the potential is reduced. The voltage dropped to about 15V to 8V. From the above, the static elimination effect of the printing apparatus 1 of the present invention was confirmed.

Other embodiments of the present invention will be described below, but the present invention is not limited thereto.
A temperature control unit such as a heating unit or a cooling unit may be provided on the mounting table 20, and static elimination or ink application may be performed while maintaining the temperature of the printing object 5 at a predetermined temperature.

The X-ray generation source 40 is not particularly limited. For example, an X-ray tube can be used. The wavelength of X-rays generated by the X-ray generation source 40 is not particularly limited. However, X-rays on the short wavelength side (with a wavelength of less than 10 ⁻¹ nm) are not preferable because they are not easily absorbed by the gas and the amount of ions generated is small. In addition, ultraviolet rays longer than X-rays ionize the gas, but if oxygen is present inside the printing chamber 2, ozone is generated, which is not preferable. Therefore, X-rays used in the present invention are more easily absorbed by gas than X-rays on the short wavelength side, have higher ionization energy than ultraviolet rays, and do not generate ozone (wavelengths from 10 ⁻¹ nm to 10 nm). The following is particularly preferable.

  The installation height of the X-ray generation source 40 and the ionizer 30 is not particularly limited, but the installation height is preferably close to the surface of the printing object 5 disposed on the mounting table 20. . For example, the height is several cm higher than the surface of the mounting table 20.

  Further, it is preferable that the printing apparatus 1 is completely covered with the printing chamber 2 in order to prevent X-rays from leaking outside the printing chamber 2 and contaminating the external environment. In order not to leak X-rays, the preferred thickness of the ceiling, side walls, and bottom wall of the printing chamber 2 is 0.5 mm or more, and the material thereof is, for example, a glass, a metal plate, or a resin plate such as a vinyl chloride plate. . In the case where the static elimination means is the ionizer 30, the thickness and material of the ceiling, side walls, and bottom wall of the printing chamber are not particularly limited.

  The arrangement and the number of the X-ray generation sources 40 are not particularly limited, but when the irradiation range of the X-ray generation sources 40 is smaller than the area of the surface of the printing object 5, a plurality of X-ray generation sources 40 are connected to the X-ray generation sources 40. If the entire surface of the printing object 5 is irradiated with X-rays so that at least a part of the irradiation range overlaps each other at an interval so as to overlap each other, the surface potential after static elimination does not vary. For example, in FIG. 2, three X-ray generation sources 40 are arranged on both sides of the printing object 5 arranged on the mounting table 20.

  Similarly, the arrangement and the number of the ionizers 30 are not particularly limited, but when the surface area of the printing object 5 is large, ions are spread over the entire surface of the printing object 5 and the surface potential after static elimination becomes uniform. Thus, it is preferable to provide a plurality of ionizers 30 around the mounting table 20.

  The ink used in the present invention is an ink in which an inorganic material or an organic material is dissolved or dispersed in water or an organic solvent. As the organic material contained in the ink, in addition to the organic light emitting material, an organic semiconductor material, a charge transfer material, an electron transfer material, an electron injection material, a charge injection material, a coloring material, and the like can be used. Only one type of organic material may be included in the ink, or two or more types may be included in the same ink. Further, an ink added with a dispersant or a surfactant may be used.

  There are no particular limitations on the type of drying gas used in the formation of the drying atmosphere or the ionizer, but a gas that does not alter the ink is preferred.For example, when the ink contains an organic material, a drying gas that does not contain water or oxygen is used. It is preferable to use it. In addition, when the components in the ink are not affected by oxygen, dry air may be used as the dry gas. In addition, one type of dry gas may be used alone, or two or more types may be mixed and used.

The printing object 5 used in the present invention is not particularly limited, but the present invention is particularly effective when the insulating material is exposed on at least a part of the surface to which the ink is applied.
The printing apparatuses 1 and 3 of the present invention are not limited to the case where the print heads 15a and 15b are moved. If the print heads 15a and 15b move relative to the print object 5, for example, the print head The printing object 5 may be moved together with the mounting table 20 with the 15a and 15b being stationary, and the printing head 5a is moved together with the mounting table 20 while the printing heads 15a and 15b are moved. You may let them.

  Further, when the printing position of the printing object 5 is concentrated on a small area, printing may be performed in a state where the print heads 15 a and 15 b are relatively stationary with respect to the printing object 5.

  The printing apparatus and the printing method of the present invention are not only for manufacturing an organic EL element, but also for an insulating property that covers a wiring pattern or a wiring pattern in a manufacturing process of a mounting part incorporating a semiconductor element or a flat display panel (FDP). It can be used for film formation of resin films, color filters, alignment films, and the like.

Sectional drawing explaining an example of the printing apparatus of this invention Plan view for explaining the positional relationship between the mounting table and the print head Sectional drawing explaining an example of a printing target object Plan view for explaining an example of a printing object Sectional drawing explaining the other example of the printing apparatus of this invention Graph showing surface potential before and after static elimination Graph showing substrate surface potential after transport and surface potential after static elimination

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 3 ... Printing apparatus 2 ... Printing room 5 ... Print object 7a, 7b ... Surface potential sensor 15a, 15b ... Print head 16a, 16b ... Nozzle 20 ... Mounting table 30 ... Ionizer 40 ... ... X-ray source

Claims (4)

A mounting table on which a printing object can be mounted;
A plurality of nozzles, and a print head capable of ejecting ink from the nozzles;
An X-ray source that emits X-rays;
The print head has a nozzle directed to the mounting table, and the ink ejected from the nozzle is configured to be applied to the surface of the printing object on the mounting table.
The X-ray generation source is disposed above the mounting table, and is configured to irradiate the X-ray on the surface of the printing object on the mounting table.
The printing object arranged on the mounting table is a printing apparatus configured to be neutralized by being irradiated with the X-ray ,
In the print head, surface potential sensors for measuring the surface potential of the print object are arranged on the front side and the rear side in the moving direction of the print head, and the print head and the surface potential sensor are described above. Configured to reciprocate together relative to the print object on the table;
When the print head moves, one of the surface potential sensors is configured to move on the print object ahead of the print head and to discharge the ink while measuring,
The surface potential sensor is connected to a control system, and when the measured value of the surface potential sensor exceeds a set value, the ejection of the ink is stopped,
The printing apparatus configured such that the print head and the surface potential sensor can be retracted to a position where no shadow of the X-ray is generated on the print object when the X-ray is irradiated. A mounting table on which a printing object can be mounted;
A plurality of nozzles, and a print head capable of ejecting ink from the nozzles;
An ionizer that discharges ionized gas,
The print head is disposed on the mounting table, and the ink ejected from the nozzle is configured to be applied to the surface of the printing object on the mounting table.
The ionizer is disposed in a position to blow the ionized gas on the printing object surface on the mounting table,
The printing object arranged on the mounting table is a printing apparatus configured to be discharged by blowing the ionized gas ,
In the print head, surface potential sensors for measuring the surface potential of the print object are arranged on the front side and the rear side in the moving direction of the print head, and the print head and the surface potential sensor are described above. Configured to reciprocate together relative to the print object on the table;
When the print head moves, one of the surface potential sensors is configured to move on the print object ahead of the print head and to discharge the ink while measuring,
The surface potential sensor is connected to a control system, and when the measured value of the surface potential sensor exceeds a set value, the ejection of the ink is stopped,
The printing apparatus, wherein the print head and the surface potential sensor can be retracted to a position where the ionized gas does not hit the nozzle when the ionized gas is sprayed . A mounting table on which a printing object can be mounted;
A plurality of nozzles, and a print head capable of ejecting ink from the nozzles;
An X-ray source that emits X-rays;
The print head is disposed on the mounting table, and the ink ejected from the nozzle is configured to be applied to the surface of the printing object on the mounting table.
The X-ray generation source is disposed above the mounting table, and uses a printing apparatus configured to irradiate the surface of the printing object on the mounting table with the X-rays.
The print head is provided with surface potential sensors for measuring the surface potential of the print object on the front side and the rear side in the moving direction of the print head, and the print head and the surface potential sensor are arranged in front of each other. When the print head moves reciprocally together relative to the print object on the mounting table, one of the surface potential sensors is placed on the print object before the print head. Keep moving
Discharging the ink while measuring the surface potential of the object to be printed before the ink is landed by the surface potential sensor;
When the measured value of the surface potential sensor exceeds a set value, the ink ejection is stopped,
The print head and the surface potential sensor are retracted to a position where a shadow of the X-ray does not occur on the print object when the X-ray is irradiated, and the print object is irradiated with the X-ray. Printing method to eliminate static electricity. A mounting table on which a printing object can be mounted;
A plurality of nozzles, and a print head capable of ejecting ink from the nozzles;
An ionizer that discharges ionized gas,
The print head is disposed on the mounting table, and the ink ejected from the nozzle is configured to be applied to the surface of the printing object on the mounting table.
The ionizer is disposed at a position where the ionized gas is sprayed onto the surface of the printing object on the mounting table.
The printing object arranged on the mounting table uses a printing apparatus configured to be discharged by blowing the ionized gas,
The print head is provided with surface potential sensors for measuring the surface potential of the print object on the front side and the rear side in the moving direction of the print head, and the print head and the surface potential sensor are arranged in front of each other. When the print head moves reciprocally together relative to the print object on the mounting table, one of the surface potential sensors is placed on the print object before the print head. Keep moving
Discharging the ink while measuring the surface potential of the object to be printed before the ink is landed by the surface potential sensor;
When the measured value of the surface potential sensor exceeds a set value, the ink ejection is stopped,
The printing head and the surface potential sensor, when the ionized gas is sprayed, retreat to a position where the ionized gas does not hit the nozzle, and the ionized gas is sprayed on the printing object to remove electricity Method.

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