JP2018130944A - Printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing device that can dry ink printed on a print matter to be printed in short time, by heating means utilizing electromagnetic waves, in particular, microwaves.SOLUTION: The printing device comprises: an ink cartridge 2; conveying means 3 that conveys a matter T to be printed toward the ink cartridge 2; an electromagnetic wave irradiator arranged in the vicinity of the downstream side in a conveying direction of the matter to be printed with respect to the ink cartridge 2; and control means 4 that controls an electromagnetic wave oscillator MW that supplies electromagnetic waves to the electromagnetic wave irradiator. The control means 4 controls oscillation output and oscillation patterns of electromagnetic waves to the electromagnetic wave irradiator so that the output is adjusted so as not to cause electric discharge at a distance between a radiation electrode and a grounding electrode, so that an ink surface of the matter T to be printed with enhanced electric field intensity is irradiated with electromagnetic waves by the electromagnetic wave irradiator to be dried.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printing apparatus, and more particularly to a printing apparatus capable of instantly evaporating ink on the surface of a printing object, particularly water-soluble ink, after printing.

  Conventionally, many techniques for drying printed ink after printing processing on a printing material by a printing apparatus have been proposed (for example, Patent Documents 1 and 2).

  These techniques heat and evaporate ink moisture by microwave dielectric heating.

Special Table 2003-534164 JP 2014-203597 A

  However, simply heating by irradiating with microwaves takes time for the water in the ink to evaporate, and there is a problem that it is difficult to sufficiently dry the printed material that moves at high speed.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a printing apparatus capable of drying ink printed on a printing material in a short time by a heating means using electromagnetic waves, particularly microwaves. Is to provide.

The printing apparatus of the present invention made to solve the above problems is as follows.
An ink cartridge provided with a nozzle part for ejecting ink into droplets;
Transport means for transporting the substrate to be printed toward the ink cartridge;
An electromagnetic wave irradiator disposed downstream from the ink cartridge with respect to the conveyance direction of the substrate;
Control means for controlling an electromagnetic wave oscillator for supplying electromagnetic waves to the electromagnetic wave irradiator,
The electromagnetic wave irradiator is composed of a boosting means including a resonance circuit that boosts electromagnetic waves oscillated from an electromagnetic wave oscillator, and a radiation electrode and a ground electrode that radiates the boosted electromagnetic waves. Increase the electric field strength between
The control means controls the electromagnetic wave oscillating output and the oscillating pattern to the electromagnetic wave irradiator so as to adjust the output so that no discharge occurs at the distance between the radiation electrode and the ground electrode. In addition, the ink surface of the object to be processed having an increased electric field intensity is irradiated with electromagnetic waves and dried.

  In the printing apparatus of the present invention, when the ink after printing is dried with an electromagnetic wave irradiator, the electric field strength in the vicinity of the surface of the printed material irradiated with the electromagnetic wave increases due to the increased electromagnetic wave, and dielectric heating due to the electromagnetic wave, particularly microwaves, is generated. Done efficiently.

  In this case, it is composed of a boosting means comprising a resonance circuit that boosts an electromagnetic wave oscillated from an electromagnetic wave oscillator, and a discharge electrode and a ground electrode that form a discharge gap. The boosting means raises the potential difference of the discharge gap and causes discharge. The plasma generator configured as described above is disposed in the vicinity of the upstream side with respect to the conveyance direction of the printing material from the ink cartridge, and the control means detects the oscillation of the electromagnetic wave to the plasma device and the timing of ejecting the ink from the ink cartridge. It can control to synchronize with. At this time, it is preferable that the plasma generator is attached so as to be integrated with a cartridge folder for storing the ink cartridge.

  According to the printing apparatus of the present invention, the heat treatment by the microwave of the ink is performed in a short time because the microwave is irradiated by increasing the electric field strength of the heated portion by the electromagnetic wave, particularly the microwave, in the heat drying of the ink. . In addition, wettability is improved by applying plasma to the surface of the substrate as a pretreatment, and the ink can be dried at an early stage in combination with the plasma treatment of the pretreatment.

1 is a schematic diagram of a printing apparatus according to a first embodiment. The electromagnetic wave irradiation device (plasma generator) used for the printing apparatus is shown, (a) is an overall cross-sectional view, (b) is a plan view of the electrode part, and (b) is a front view of a part of the electrode part cut away. is there. It is a front view of the partial cross section which shows the structural example of the plasma generator provided with the plasma jet function. It is the equivalent circuit of the pressure | voltage rise means of the electromagnetic wave irradiation device (plasma generator). 4A and 4B are schematic views of a substrate-type plasma generation apparatus used in the printing apparatus of Embodiment 3, wherein FIG. 5A is a schematic view of a first substrate, FIGS. 5B and 5C are schematic views of an intermediate substrate, and FIG. Schematic diagram of two substrates, (e) is a cross-sectional view in a state of being housed in a case. It is a front view of the substrate type plasma generation apparatus. It is the equivalent circuit of the pressure | voltage rise means of the same plasma generator.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

<Embodiment 1> Printing apparatus Embodiment 1 is a printing apparatus according to the present invention. As shown in FIG. 1, the printing apparatus 1 according to the present invention includes an ink cartridge 2 including a nozzle unit that ejects ink in droplets, a conveyance unit 3 that conveys a printing material T toward the ink cartridge 2, and An electromagnetic wave irradiator 8 disposed in the vicinity of the downstream side of the ink cartridge T with respect to the conveyance direction of the printing material, and a control means 4 for controlling the electromagnetic wave oscillator MW that supplies the electromagnetic wave to the electromagnetic wave irradiator 8. The irradiator 8 is composed of a boosting means composed of a resonance circuit that boosts the electromagnetic wave oscillated from the electromagnetic wave oscillator MW, and a radiation electrode and a ground electrode that radiates the boosted electromagnetic wave. The control means 4 outputs the oscillation output and oscillation pattern of the electromagnetic wave to the electromagnetic wave irradiator 8 so that no discharge occurs at the distance between the radiation electrode and the ground electrode. By controlling to adjust so that, by the electromagnetic wave irradiator 8, so that drying by irradiating the electromagnetic wave to the ink surface of the object T of increased field intensity. The electromagnetic wave irradiator 8 is preferably attached to the cartridge folder 5 that houses the ink cartridge 2.

  Further, in the vicinity of the upstream side with respect to the transport direction of the substrate T from the ink cartridge 2, a boosting means comprising a resonance circuit that boosts the electromagnetic wave oscillated from the electromagnetic wave oscillator MW, a discharge electrode and a ground electrode that form a discharge gap, It is possible to dispose a plasma generator 6 configured to increase the potential difference of the discharge gap by the boosting means and generate discharge. The plasma generator 6 controls the electromagnetic wave oscillation of the plasma generator 6 by the control means 4 that controls the electromagnetic wave irradiator 8 so as to synchronize with the timing of ink ejection from the ink cartridge. The structure of the plasma generator 6 can be the same as that of the electromagnetic wave irradiator 8. The electromagnetic wave oscillator MW and the control means 4 can be provided separately from the electromagnetic wave irradiator 8, but can also be used as the electromagnetic wave irradiator 8.

<Electromagnetic wave irradiator>
The electromagnetic wave irradiator 8 of the present embodiment includes an input unit 52 that receives supply of an electromagnetic wave oscillated from an electromagnetic wave oscillator MW, a boosting unit 50 that boosts the input electromagnetic wave (for example, 2.45 GHz microwave), and a booster A radiation electrode 55a and a ground electrode 51a for radiating the electromagnetic wave, and the step-up means 50 increases the electric field strength between the radiation electrode 55a and the ground electrode 51a and in the space near the radiation electrode 55a and the ground electrode 51a. It is configured.

  The radiation electrode 55a is formed at the tip of an electrode shaft portion 55b extending from the bottomed tubular portion 54 through which the input shaft portion 53 extending from the input portion 52 is inserted to the side opposite to the input portion. An input shaft portion 53 extending from the input portion 52 is insulated from the cylindrical portion 54. Specifically, a cylindrical insulator 59 is interposed between the inner peripheral surface of the cylindrical portion 54. By constituting the insulator 59 so as not to be in contact with the inner peripheral surface of the cylindrical portion 54, the cylindrical portion 54 and the input shaft portion 53 are capacitively coupled, and form an equivalent circuit C1 described later. Further, the cylindrical portion 54 and the electrode shaft portion 55 b are also electrically insulated from the inner peripheral surface of the front end side casing 51 </ b> A of the casing 51. In the present embodiment, the cylindrical portion 54 and the electrode shaft portion 55 b are enclosed in a cylindrical insulator 59. An equivalent circuit C2 described later is formed between the outer peripheral surface of the cylindrical portion 54 and the inner peripheral surface of the casing 51A covering the cylindrical portion 54, and between the electrode shaft portion 55b and the inner peripheral surface of the casing 51A. An equivalent circuit capacitor C3 is formed. The resonance frequency is adjusted by the dielectric constant that varies depending on the type of the insulator 59. In addition, C1 mentioned above can also be abbreviate | omitted by connecting the input shaft part 53 with the cylindrical member 54 electrically.

  The casing 51B on the rear end side of the casing 51 has a through hole. An input portion 52 that receives supply of electromagnetic waves from the electromagnetic wave oscillator MW is formed at one end of the casing 51B, and an input shaft portion 53 that extends from the input portion 52 is formed at the other end. A protruding tubular insulator 59 is disposed, and a radiation electrode 55a, a tubular portion 54, an electrode shaft portion 55b, and a casing 51A including the insulator 59 covering these are incorporated. The method of incorporating the input portion 52, the input shaft portion 53, and the casing 51A of the insulator 59 covering them is not particularly limited, but in the present embodiment, it corresponds to the outer peripheral surface of the insulator 59 and the through hole of the casing 51B. The step is inserted from the left side of the figure to engage the insulator with the step to prevent falling off to the right side, and the casing 51A is inserted from the left side to cover the input portion 52, the input shaft portion 53 and these. The falling of the insulator 59 to the left side is also prevented. Although the method for fixing the casing 51A to the casing 51B is not particularly limited, in the present embodiment, the fixing is performed by screwing the male screw portion engraved on the outer peripheral surface of the casing 51A into the female screw portion engraved in the through hole. To do. After fixing by screwing, the casing 51A can be securely fixed to the casing 51B using a fixing means such as welding, or can be fixed using a fixing means such as welding without forming a threaded portion. it can.

  The ground electrode 51a is formed at the tip of a cylindrical casing 51A that covers the radiation electrode 55a, and forms a certain gap between the inner surface of the ground electrode 51a and the outer surface of the radiation electrode 55a. The ground electrode 51a (the tip of the casing 51A) forming this gap forms a slit s as shown in FIG. The distance between the radiation electrode 55a and the ground electrode 51a is preferably set in the range of 0.2 to 1.2 mm, and the discharge is performed depending on the output of the electromagnetic wave supplied from the electromagnetic wave oscillator MW described later, the oscillation time, the oscillation interval, and the number of oscillations. It is a distance that does not occur.

  The boosting means 50 is constituted by an equivalent circuit shown in FIG. The step-up means 50 uses the electrode shaft portion 55b as a coil L, forms a resonance structure at three positions between the capacitors C1, C2, and C3 described above, and steps up the supplied electromagnetic wave. In particular, the first resonance region by the capacitor C2 formed between the outer peripheral surface of the cylindrical portion 54 and the inner peripheral surface of the casing 51 that covers the cylindrical portion 54, and the casing 51 that covers the electrode shaft portion 55b and the electrode shaft portion 55b. Is boosted by the second resonance region formed by the capacitor C3 between the radiating electrode 55a and the ground electrode 51a, and the electric field strength in the space near the radiating electrode 55a and the ground electrode 51a is increased. I try to increase it. In addition, it can also be set as the structure which does not form C1 of an equivalent circuit by electrically connecting the input shaft part 53 and the cylindrical part 54, and not carrying out capacitive coupling.

  The electromagnetic wave oscillator MW is always supplied with a predetermined voltage, for example, 12 V from the electromagnetic wave power source P. Then, an electromagnetic wave (eg, 2.45 GHz microwave) is output from the control means 4 as a pulse wave of an oscillation pattern in which an electromagnetic wave oscillation signal is set with a predetermined duty ratio, pulse time, and the like.

  Specifically, the supply of electromagnetic waves in which plasma is not generated (no dielectric breakdown occurs) is performed when the distance between the radiation electrode 55a and the ground electrode 51a is about 0.2 to 1 mm, and the peak output is less than 500 W, preferably 300 W or less. Supply electromagnetic waves. Further, it is preferable that the oscillation pattern has an oscillation time of 2 to 3 μs and a duty ratio of 60 to 90%. In this embodiment, control is performed so that the duty ratio is 83% at an oscillation time of 2.5 μsec and an oscillation cycle of 3 μsec. As a result, the average output is 100 to 200 W, and in this embodiment, the average output is 145 W.

  The electromagnetic wave irradiator 8 is attached to an arm extending from the cartridge folder 5 of the ink cartridge 2 so that the position in the vertical direction can be adjusted. Thereby, the clearance gap between the front end surface by the side of the irradiation electrode 55a of the electromagnetic wave irradiation device 8 and the surface of the to-be-printed material T can be adjusted. The distance M (see FIG. 2C) between the front end surface of the electromagnetic wave irradiator 8 on the irradiation electrode 55a side and the surface of the printing material T is as much as possible within the range where it does not come into contact with the ink printed by the in-cartridge 2. According to the experiments by the present inventors, the distance of about 1 to 2 mm is used, and the surface of the ink after printing is caused by electromagnetic waves (microwaves) irradiated in the region E where the electric field strength is increased. Induction heating is effectively received. This makes it possible to dry the ink for a short time.

<Plasma generator>
The plasma generator 6 according to the present embodiment includes an input unit 52 that receives the supply of electromagnetic waves oscillated from the electromagnetic wave oscillator MW, a boosting unit 50 that boosts the input electromagnetic waves (for example, 2.45 GHz microwaves), and a booster. The discharge electrode 55a that radiates the electromagnetic wave and the ground electrode 51a are provided, and the voltage difference of the discharge gap G is increased by the boosting means 50 to cause discharge. The basic structure is the same as that of the electromagnetic wave irradiator 8, and the radiation electrode of the electromagnetic wave irradiator 8 functions as a discharge electrode. The output of the electromagnetic wave to be supplied, the oscillation time, the duty ratio, especially the output of the electromagnetic wave is irradiated with the electromagnetic wave. It is larger than 5 and is controlled so that dielectric breakdown occurs in the discharge gap G by boosting the electromagnetic wave.

  Specifically, the supply of electromagnetic waves in which plasma is generated (dielectric breakdown occurs) is such that when the distance between the discharge electrode 55a and the ground electrode 51a is about 0.2 to 1 mm, the peak output is 500 W or more, preferably 800 W or more. Supply electromagnetic waves. Further, as the oscillation pattern, it is preferable that the oscillation time is 0.1 to 2 μs and the duty ratio is 10 to 40%. In this embodiment, control is performed so that the duty ratio is 25% with an oscillation time of 0.5 μsec and an oscillation cycle of 2 μsec. As a result, dielectric breakdown occurs in the discharge gap and plasma is generated, so that the wettability of the surface of the substrate T to be in contact with the plasma is improved.

  Although the plasma generated in the discharge gap G of the plasma wave generator 5 may be configured as shown in FIG. 1 so as to directly contact the substrate T, the casing 51 is covered as shown in FIG. A nozzle cap 7 can also be arranged on the front. A space serving as a predetermined gap is provided between the inner peripheral surface of the nozzle cap 7 and the casing 51, and compressed air is provided between the external compressed air generator A and the compressed air introduction port 7 b opened in the nozzle cap 7. Connected by the introduction pipe 70, compressed air is supplied to the space between the inner peripheral surface of the nozzle cap 7 and the casing 51. Then, the plasma jet 7a provided at the tip of the nozzle cap 7 is positioned in the vicinity of the discharge gap G of the plasma generator 6, so that the plasma generated in the discharge gap G becomes a plasma jet from the plasma jet 7a to the substrate T. Is erupted. The pressure flow rate of the compressed air generator A is adjusted by the control means 4, and the humidity is adjusted by the humidifier B provided in the flow path of the compressed air as necessary. At this time, the injection amount of compressed air is preferably about 5 liters / minute to 20 liters / minute.

  Moreover, the plasma generation apparatus can also use the plasma generation apparatus 9 using a flat plate type electromagnetic wave shown in FIG. The plasma generator 9 is configured by forming a predetermined pattern on a plurality of insulating substrates and laminating them. The insulating substrate has a rectangular shape, and an input terminal portion is formed at one end and a plasma generation portion (discharge portion) is formed at multiple ends. The plasma generation device 9 is disposed so as to be integrated with the ink cartridge 2 and is attached so that the height from the printing surface on which the ink cartridge 2 prints can be finely adjusted.

The insulating substrate is formed by firing a powder (hereinafter referred to as a ceramic raw material) of ceramics (for example, alumina (Al ₂ O ₃ ), aluminum nitride, cordierite, mullite, etc.). In this embodiment, a single-layer ceramic insulating substrate can be used. Specifically, a uniform slurry is produced by adding a binder / solvent to the ceramic raw material and mixing and grinding. Thereafter, the mixture is granulated by spray drying (spray drying) to form granules. The granules are formed into a ceramic molded body having a desired shape by CIP molding (cold isostatic pressing), press molding, injection molding or the like, and then fired in a firing furnace. CIP molding is suitable for molding small plate-like bodies by placing granules in a rubber mold and molding using water pressure, and press molding is a process for placing granules in a mold and molding. This is the most suitable method for forming the insulating substrate having the form. In addition to the materials described above, the insulating substrate may be a plate made of resin, such as polytetrafluoroethylene or glass epoxy material that is a fluororesin.

  The resonance electrode 93 constituting the central electrode 92 and the discharge electrode 93a formed on the insulating substrate is made of a conductive paste mainly composed of metal powder (for example, silver, copper, tungsten, molybdenum, etc. having low electrical resistance) as shown in FIG. Although printing is performed on an insulating substrate by a technique such as screen printing so as to obtain a configuration as shown in a) and (d), the present invention is not limited to this.

  The plasma generation apparatus 9 is configured such that four substrates are stacked and accommodated in a hollow prismatic case 90. The substrates 91B and 91C, which are intermediate substrates, are a single substrate in consideration of the thickness. Can also be configured.

  The first substrate 91A has a central electrode 92 formed on the main surface, an input unit 95 (for example, an SMA connector) connected to an external electromagnetic wave oscillator MW at one end of the short side, and a predetermined thickness and length at multiple ends. An antenna portion 92a having a thickness is provided.

  The second substrate 91D includes a resonance electrode 93. The resonance electrode 93 includes a discharge portion 93a, a resonance portion 93b, and a connecting portion 93c that electrically connects the discharge portion 93a and the resonance portion 93b. The discharge part 93a is configured so as to face the antenna part 92a when stacked. Further, both sides of the discharge portion 93a are provided with notches so that the ground electrode portion 90a formed at the end portion of the case 90 enters when the substrate laminated on the case 90 is stored. As a result, the short side where the discharge part 93a is formed becomes convex.

  In the above configuration, an electromagnetic wave (2.45 GHz microwave in this embodiment) supplied from the external electromagnetic wave oscillator MW is transmitted from the antenna portion 92a of the center electrode 92 to the resonance portion 93b of the resonance electrode 93 via the discharge portion 93a. As a result, the voltage is increased and the potential difference between the discharge portion 93a of the resonance electrode 93 and the ground electrode 90a is increased. As a result, primary plasma SP1 is generated between the discharge part 93a and the ground electrode 90a (see FIG. 6). The antenna portion 92a and the discharge portion 93a form a capacitor that is capacitively coupled. An equivalent circuit of the boosting means of the plasma generator 6 is shown in FIG.

  The generation of the primary plasma SP1 causes impedance mismatch, but electromagnetic waves passing through the center electrode 92 not passing through the resonance part are supplied from the antenna part 92a to the primary plasma SP1, and the primary plasma SP1 is maintained. Enlarged. The plasma generated in this manner improves the adhesion of ink by modifying the surface of the substrate T on the upstream side of the ink cartridge 2 of the printing apparatus and improving the wettability as in the first embodiment.

  Moreover, since the electromagnetic wave oscillator MW is a pulse oscillation device that can arbitrarily change the electromagnetic wave (microwave) from nanoseconds to milliseconds as described above, various pulse oscillation patterns can be easily changed. This makes it possible to easily control the type of radical generated by changing the energy state during ionization. Furthermore, even if the printing surface is not a flat surface but a curved surface, the plasma generating device 9 is mounted so that the height from the printing surface of the ink cartridge 2 can be finely adjusted. Thus, plasma can be generated in the gap and the surface of the substrate T can be well modified.

  The flat plate type plasma generating apparatus 9 using electromagnetic waves has the advantage that the structure is simple, the manufacturing is simple, the cost can be reduced, and the plasma region is easier to expand than the cylindrical type. .

<Operation of printing device>
A printing operation of the printing apparatus 1 according to the present embodiment will be described. Upon receipt of the print command, the control means 4 transmits a print command to the cartridge 2 and transmits an electromagnetic wave oscillation signal to the electromagnetic wave power source P and the electromagnetic wave oscillator MW so as to oscillate the electromagnetic wave to the plasma generator 6 in accordance with the print timing. To do.

  Moreover, the conveyance means 3 in this embodiment shows the example in the case of printing on the to-be-printed material T wound by roll shape, and the storage roller 31 which sets the roll-shaped to-be-printed material T, and the to-be-printed material T are substantially horizontal. The feed base 30 printed by the ink ejected from the ink cartridge 2, the feed roller 33 that feeds the substrate T drawn from the storage roller 31 to the feed base 30, and the printed substrate T are wound. The take-up roller 35 to be taken, the receiving roller 34 to deliver the print T to the take-up roller 35, the tension between the storage roller 31 and the feed roller 33 and the take-up roller 35 and the take-up roller 34 to the print T The tension roller 32 is provided.

  By this conveying means 3, the print target portion of the substrate T is sequentially sent below the ink cartridge 2 for printing. The plasma generator 6 irradiates the surface of the substrate T to be printed with a plasma before printing from the cartridge 2 to improve the wettability of the surface. As a result, the contact angle of the ink with respect to the surface of the printing material is reduced, which contributes to drying in a short time. Further, the wetness of the plasma generator 6 is improved, and the ink surface printed by the ink cartridge 2 approaches the vicinity of the tip of the electromagnetic wave irradiator 8 where the electric field strength is high and the electromagnetic wave is irradiated. The ink is heated over time, and the ink is dried in a short time. At this time, when the ink is a water-soluble ink, induction heating by electromagnetic waves (microwaves) is particularly effectively promoted.

  In particular, the plasma generator 6 improves the wettability of the surface of the substrate T to reduce the ink contact angle, thereby reducing the amount of ink required for printing. Thereby, the heating efficiency by the electromagnetic wave irradiator 8 is improved. Further, by adding a powdery electromagnetic wave absorber, such as carbon microcoil or carbon nanocoil, to the ink, the heating efficiency is further improved by heating not only from the ink surface but also from the inside.

  As described above, the printing apparatus of the present invention can be suitably used as a newly designed printing apparatus, and can also be suitably used as an improvement of an existing printing apparatus.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Ink cartridge 3 Conveyance means 4 Control means 5 Cartridge folder 6 Plasma generator 7 Nozzle cap 8 Electromagnetic wave irradiation device

Claims (2)

An ink cartridge provided with a nozzle part for ejecting ink into droplets;
Transport means for transporting the substrate to be printed toward the ink cartridge;
An electromagnetic wave irradiator disposed downstream from the ink cartridge with respect to the conveyance direction of the substrate;
Control means for controlling an electromagnetic wave oscillator for supplying electromagnetic waves to the electromagnetic wave irradiator,
The electromagnetic wave irradiator is composed of a boosting means including a resonance circuit that boosts electromagnetic waves oscillated from an electromagnetic wave oscillator, and a radiation electrode and a ground electrode that radiates the boosted electromagnetic waves. Increase the electric field strength between
The control means controls the electromagnetic wave oscillating output and the oscillating pattern to the electromagnetic wave irradiator so as to adjust the output so that no discharge occurs at the distance between the radiation electrode and the ground electrode. A printing apparatus in which an ink surface of an object to be processed with an increased electric field intensity is irradiated with an electromagnetic wave to be dried. The booster is composed of a resonance circuit that boosts an electromagnetic wave oscillated from an electromagnetic wave oscillator, and a discharge electrode and a ground electrode that form a discharge gap. The booster increases the potential difference of the discharge gap and generates discharge. A plasma generator is disposed in the vicinity of the upstream side with respect to the conveyance direction of the substrate from the ink cartridge,
The printing apparatus according to claim 1, wherein the control unit controls the oscillation of an electromagnetic wave to the plasma device so as to synchronize with an ink ejection timing from the ink cartridge.

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