JP2018083369A - Continuous ejection type ink jet printing device and method of preventing immixing of foreign matter for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent immixing of foreign matter into a head part of a continuous type ink jet printer.SOLUTION: Air is supplied to a nozzle 53 of a cover 50 through a solenoid valve 57 so that the pressure inside the cover 50 becomes higher than the atmospheric pressure. When a sensor (not shown in the figure) detects a workpiece, the air supply from the nozzle 53 is stopped. After detecting the workpiece, printing is performed. As a result, the air is supplied upon non-printing, the inside of the cover 50 becomes the positive pressure, and the air is injected from a hole 51. The air supply is stopped, on the other hand, upon the printing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a continuous discharge type inkjet printing apparatus, and more particularly to prevention of foreign matter contamination.

  2. Description of the Related Art Conventionally, a printing system that prints a barcode or the like with an ink jet printer from a side surface of a cardboard moving on a conveyor is known (see Non-Patent Document 1).

  In general, a DOD (drop on demand) type in which ink is discharged at a timing when a printer is printing is used for printing on a cardboard.

  As a type other than the DOD type, a continuous discharge type (CIJ) is known. In this method, a circulation of small droplets of ink is formed, and a character in which a part of the droplet is bent on a track with a deflection electrode and attached to a product is formed. Unused droplets are collected and again made part of the ink circulation.

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  When printing with an ink jet printer, the DOD type uses water-based or oil-based ink, so that there is a problem that the printed portion is blurred when wet.

  On the other hand, CIJ type uses solvent-based ink, so there is no such problem, but it is premised on collecting unused droplets. Therefore, in an environment where there are many foreign matters such as dust and dust, Otherwise, it may cause a malfunction. That is, there was a problem that it was inferior in dust resistance.

  Such dust resistance is particularly problematic when printing on the lower surface of an object. This is because the discharge is made in the anti-gravity direction, so that foreign matter is more easily mixed by gravity.

  An object of the present invention is to solve such problems and to provide a continuous discharge type inkjet printing apparatus excellent in dust resistance.

  (1) The continuous discharge type ink jet printing apparatus according to the present invention receives a change command, a discharge unit that continuously discharges the supplied ink as ink particles, and changes the traveling direction of the discharged ink particles to the object. A direction changing unit that changes the direction, a receiving unit that receives ink particles whose course has not been changed, a collecting unit that collects ink particles that have reached the receiving unit, at least the ejection unit, the deflecting unit, and the receiving unit A casing having a discharge port for discharging the ink particles to the outside, and a cover portion for covering the casing having a passage port through which the ink particles discharged from the discharge port pass. A gas supply means for preventing foreign matter from entering the cover part from the outside of the cover port, and a gas supply control means for controlling the supply of the gas supply means. Pressure control means, depending on the timing of receiving the change instruction, so that the traveling direction does not influence on the traveling direction of the modified ink particle, stopping the gas supply.

  Thereby, the inside of the cover part can be set to a positive pressure during non-printing. Therefore, it can prevent that a foreign material mixes.

  (2) In the continuous discharge type inkjet printing apparatus according to the present invention, the discharge unit is located below the object. Therefore, even when printing is performed on the lower surface of the object to be printed, foreign matter can be prevented from being mixed.

  (3) In the continuous discharge type inkjet printing apparatus according to the present invention, the preliminary pressure for supplying the casing with a gas having a pressure that does not affect the movement of the ink particles from the discharge unit to the receiving unit. Supply means are provided. Therefore, the inside of the housing can be made positive pressure even during printing.

  (4) In the continuous discharge type inkjet printing apparatus according to the present invention, the lower part of the cover is in an open state. Therefore, a cover part can be formed easily.

  (5) In the continuous discharge type ink jet printing apparatus according to the present invention, the gas given in the casing is about 1.2 atm, and the gas given to the cover is about 1.5 atm. Therefore, the inside of the cover can be positively positive when not printing. Further, the inside of the housing can always be a positive pressure.

  (6) The foreign matter mixing prevention method for the continuous discharge type ink jet print head according to the present invention causes the ink particles to be continuously discharged, and when a change command is received, the traveling direction of the discharged ink particles is directed to the object. A method for preventing foreign matter from being mixed into a continuous discharge type ink jet print head that performs desired printing by changing the head, covering the head with a cover portion having a passage port through which ejected ink particles pass, Then, the gas is supplied to the cover so that the gas is discharged, and the supply of the gas is stopped according to the timing when the change command is received.

  Thereby, the inside of the cover part can be set to a positive pressure during non-printing. Therefore, it can prevent that a foreign material mixes.

  The correspondence between the terms in the claims and the terms used in the present embodiment will be described. The discharge part is the nozzle 1, the direction changing part is the charging electrode 2 and the deflection electrode 3, the receiving part is the gutter 5, the recovery part is the circulation part 6, the housing is the head 10, and the cover part is the cover 50. The hole corresponds to the hole 51, the gas supply means corresponds to the solenoid valve 57 and the nozzle 53, the gas supply control means corresponds to the MPU 122 and the air controller 131, and the preliminary pressure supply means corresponds to the precision regulator 57 and the nozzle 55, respectively.

It is a figure which shows the structure of the inkjet type printing apparatus concerning this invention. 3 is a perspective view of a cover 50. FIG. It is a timing chart which shows the relationship between printing and the supply timing of air.

  FIG. 1 shows an ink jet printing apparatus 100 according to the present invention. The ink jet printing apparatus 100 includes a head unit 10 and a main body unit 20.

  The main unit 20 includes an MPU 122, a ROM 123, a RAM 124, a storage device 125, an input panel 126, a display device 127, a bus line 128, an excitation voltage generation circuit 129, a charging voltage generation circuit 130, a high voltage control circuit 132, and an air controller 131. I have.

  An MPU (microprocessing unit) 122 controls the entire inkjet recording apparatus. A ROM (read only memory) 123 stores a control program and data necessary for the MPU 122 to operate. A RAM (rewritable memory) 124 temporarily stores data required during program execution. The storage device 125 stores programs, print data, and the like. The input panel 126 inputs print contents and set values, and the display device 127 displays input data and print contents. The bus line 128 transmits the data signal, address signal, and control signal of the MPU 122. The excitation voltage generation circuit 129 applies a voltage for atomizing the ink. The charging voltage generation circuit 130 generates a voltage for charging the ink particles. The high voltage control circuit 132 applies a deflection voltage to the deflection electrode 3.

  The head unit 10 will be described.

  The head 10 houses a nozzle 1, a charging electrode 2, a deflection electrode 3, a gutter 5, and a circulation unit 6, and performs continuous ink jet printing. The head 10 has a hole 11.

  The plate 70 is moved in the arrow α direction by a conveyor (not shown). A workpiece detection sensor (not shown) detects that the plate 70 has reached a predetermined position.

  An excitation voltage is applied to the nozzle 1 by an excitation voltage generation circuit 129. Thereby, the nozzle 1 particles the ink supplied from the pump 32 and discharges the ink particles. The charging electrode 2 charges the ink particles with the voltage supplied from the charging voltage generation circuit 130. The ink particles are collected by the ink collecting gutter 5, passed through the path 6, and supplied to the nozzle 1 again by the pump 32.

  Upon receiving the detection signal of the workpiece detection sensor, the MPU 122 sends a change signal to the deflection electrode 3 by the high voltage power source 4. As a result, the traveling direction of the charged ink particles is changed. The ink particles whose traveling direction has been changed pass through the holes 11 and 51, reach the plate 70 which is the printing material, and are printed.

  Air is supplied into the head 10 and the cover 50 as follows. Thereby, even a continuous ink head that collects ink particles that have not been used for printing can prevent clogging due to foreign matter, as will be described below.

  As shown in FIG. 2, the cover 50 has a cylindrical shape in which an ink discharge hole 51 is provided in the upper part and the lower part is opened. In the present embodiment, the hole 51 has an oval shape that is long in the direction orthogonal to the arrow α direction, but the shape of the hole is not limited.

  As shown in FIG. 1, the cover 50 is provided with a nozzle 53 on the side surface. Air is supplied to the nozzle 53 via an electromagnetic valve 57. In the present embodiment, the output pressure in the electromagnetic valve 57 is set to atmospheric pressure + 0.5 atm. However, this is not limited, and the point is that the pressure inside the cover 50 is higher than the atmospheric pressure. Good. It depends on the size of the hole 51, the degree of opening of the lower part of the cover 50, the volume of the head 10, and the like.

  The air supply timing by the MPU 122 will be described with reference to FIG. When the workpiece detection sensor (not shown) detects a workpiece, the air supply from the nozzle 53 is stopped. After a predetermined time elapses after the workpiece is detected, the high voltage control circuit 132 is turned on, whereby the traveling direction of the ink particles is changed and printing is performed.

  Air supply is stopped as follows. The MPU 122 gives a stop command to the air controller 131 when the work detection sensor (not shown) detects a work. The air controller 131 gives a close signal to the electromagnetic valve 57. Thereby, the air supplied to the electromagnetic valve 57 is stopped. That is, air is supplied during non-printing, the inside of the cover 50 is at a positive pressure, and air is ejected from the holes 51, but such air supply is stopped during printing.

  Note that air near the atmospheric pressure + about 0.2 atmospheric pressure is constantly supplied from the precision regulator 59 by the nozzle 55 from the vicinity of the ink particle ejection hole 11 of the head 10. By supplying such a pressure of about +0.2 atm to the head 10, even when the pressurization by the nozzle 53 is stopped, the inside of the head 10 is kept at a positive pressure, and foreign matter is introduced into the head 10 from the hole 11. Mixing can be prevented. The degree of pressurization is not limited to this as long as it does not affect the course of ink particles.

  In the present embodiment, the case where the pump 32 and the high-voltage power supply 4 are physically separated from the main body 20 has been described. However, the pump 32 and the high-voltage power supply 4 may be built in the main body 20 or the head 10.

  In the present embodiment, the cover 50 has a shape that covers about 先端 of the tip of the head 10, but it may cover a larger area. Furthermore, it is arbitrary whether an open part is provided in the lower part.

  In the above-described embodiment, the continuous ink jet type print head is printed by charging and deflecting, but other methods may be used.

  In the present embodiment, the case where printing is performed on the printing object from the lower side has been described. However, in an environment with a lot of dust and dust, the head can be configured in the same manner even if printing is not performed on the lower side. Foreign matter can be prevented from entering 10.

  In the present embodiment, the air supply is stopped by the work detection sensor. However, in short, it is sufficient that the air supply can be stopped a little before printing, and the air supply may be stopped by other means. .

10 ・ ・ ・ ・ ・ ・ Head
11 ・ ・ ・ ・ ・ ・ Hole
20 ・ ・ ・ ・ ・ ・ Main body
50 ・ ・ ・ ・ ・ ・ Cover
51 ・ ・ ・ ・ ・ ・ Hole
53 ・ ・ ・ ・ ・ ・ Nozzle
55 ・ ・ ・ ・ ・ ・ Nozzle
57 ・ ・ ・ ・ ・ ・ Solenoid valve

Claims (6)

An ejection unit that continuously ejects the supplied ink as ink particles;
Upon receiving the change command, a direction changing unit that changes the traveling direction of the ejected ink particles toward the object,
A receiving portion for receiving ink particles whose course has not been changed,
A collecting unit for collecting the ink particles reaching the receiving unit;
A housing that covers at least the ejection unit, the deflection unit, and the receiving unit, and has a ejection port that ejects the ink particles to the outside;
A continuous discharge type inkjet printing apparatus comprising:
A cover that covers the housing, the cover having a passage port through which ink particles discharged from the discharge port pass;
A gas supply means for preventing foreign matter from being mixed into the cover part from the outside of the passage opening of the cover part;
Gas supply control means for controlling the supply of the gas supply means;
With
The gas supply control means stops the gas supply so that there is no influence on the traveling direction of the ink grains whose traveling direction has been changed according to the timing of receiving the change command;
A continuous discharge ink jet printing apparatus characterized by the above. The continuous discharge type inkjet printing apparatus according to claim 1,
The discharge part is located below the object;
A continuous discharge ink jet printing apparatus characterized by the above. The continuous discharge inkjet printing apparatus according to claim 1 or 2, further comprising:
Preliminary pressure supply means for supplying a gas having a pressure that does not affect the movement of ink particles from the ejection unit to the receiving unit to the housing;
Having
A continuous discharge ink jet printing apparatus characterized by the above. In the continuous discharge type inkjet printing apparatus according to claim 2 or 3,
The lower part of the covering part is in an open state;
A continuous discharge ink jet printing apparatus characterized by the above. In the continuous discharge type inkjet printing apparatus according to claim 3,
The gas given in the casing is about 1.2 atm.
The gas given to the cover is about 1.5 atm.
A continuous discharge ink jet printing apparatus characterized by the above. When ink particles are ejected continuously and a change command is received, foreign matter is prevented from entering the continuous ejection ink jet print head that performs desired printing by changing the direction of travel of the ejected ink particles toward the object. A method,
Cover the head with a cover portion having a passage port through which the ejected ink particles pass;
Supplying gas to the cover so that the gas is discharged from the passage port, and stopping the supply of the gas according to the timing of receiving the change command,
A method for preventing foreign matter from being mixed into a continuous discharge type inkjet print head.

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