JP7045805B2 - Inkjet recording device and inkjet recording method - Google Patents

Description

The present invention relates to an inkjet recording apparatus and an inkjet recording method for forming and printing ink particles by ejecting ink from a nozzle.

After ink is ejected from a nozzle to form ink particles, the ink particles are charged and deflected, and characters in a two-dimensional matrix are recorded on a printed object that moves in a direction approximately perpendicular to the deflection direction of the ink particles. In an inkjet recording device, when ink particles used for recording fly in close proximity, mutual interference occurs due to Coulomb force and air resistance. Patent Document 1 is a technique for suppressing deterioration of print quality (print distortion) due to a shift in the flight trajectory of ink particles due to these mutual interferences. In Patent Document 1, by flying ink particles that are not used for printing between the ink particles used for printing, the speed reduction caused by the air resistance acting on the ink particles used for printing is reduced, and the ink particles are used for printing. It is disclosed that the printing distortion in which the ink particles deviate from a predetermined printing position is reduced.

Japanese Unexamined Patent Publication No. 08-118654

In Patent Document 1, the air resistance acting on the ink particles used for printing (hereinafter referred to as recording ink particles) changes depending on the flight pattern of the recording ink particles flying in front of the recording ink particles, so that printing is performed for each printing pattern. It is necessary to determine the charge amount and arrangement of the ink particles (hereinafter, dummy particles) that are not used, and there is a problem that it takes time to determine the charge amount.

In view of the above background technique, the present invention, for example, includes a nozzle for ejecting ink particles, a charged electrode for charging the ejected ink particles, and ink particles when the charged ink particles fly in an electric field. The ink particles are composed of recording ink particles used for printing and dummy ink particles not used for printing, and the recording ink particles whose flight direction is deflected are printed on the object to be printed. It is an inkjet recording device that prints by adhering it to the inside of the print area. A plurality of first dummy ink particles to fly are generated at a timing earlier than that of the recording ink particles.

According to the present invention, since the recording ink particles fly in the wake layer formed by the wake of the dummy ink particles flying ahead of the recording ink particles, the recording ink particles do not depend on the flight pattern of the recording ink particles. Since the difference in air resistance acting on the ink particles and the air resistance between the recording ink particles can be reduced, printing distortion in the deflection direction of the recording ink particles and the transport direction of the printing target can be reduced.

It is a figure which shows the ink circulation system of the ink jet recording apparatus and the flight form of the ink particle in an Example. It is a figure which shows the dot arrangement on the printed matter when the character of the 2D matrix of 5 rows and 5 columns is printed on the printed matter by the inkjet recording apparatus in an Example. It is a figure which shows the 1st example of the charge voltage pattern to the ink particle of the inkjet recording apparatus in an Example. It is explanatory drawing of the flying state of the ink particle of the inkjet recording apparatus in an Example. It is a figure which shows the 2nd example of the charge voltage pattern to the ink particle of the inkjet recording apparatus in an Example. It is the schematic of the apparatus appearance of the inkjet recording apparatus in an Example. It is the schematic of the inside of the device of the inkjet recording apparatus in an Example. It is a circuit block diagram of the inkjet recording apparatus in an Example.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

First, the appearance configuration of the inkjet recording apparatus in this embodiment will be described with reference to FIG. In FIG. 6, the inkjet recording device includes a main body 600 that houses a control system and a circulation system, a print head 610 that ejects ink particles, and a cable 620 that connects the main body 600 and the print head 610. The length of the cable 620 is generally 2-6 m. The main body 600 is provided with a touch panel type liquid crystal panel 630 that allows a user to input print contents, print specifications, etc., and display control contents, device operation status, and the like. Inside the print head 610, nozzles forming ink particles and electrodes for charging and deflecting the ink particles are housed, and are covered with a stainless steel cover. An opening 640 through which ink particles can pass is formed at the tip of the print head 610. Further, a door 670 that can be opened and closed is provided at the lower part of the main body 600, from which internal maintenance can be performed.

Next, the internal configuration of the main body 600 will be described with reference to FIG. 7. In FIG. 7, electrical components such as a control circuit 645 are arranged on the upper part of the main body 600. Circulation system control parts such as a solenoid valve unit 650 and a pump unit 655 are arranged in the lower part 680 of the main body, and an ink container 1 storing ink to be supplied to a nozzle is stored in the lower part 660 of the main body. By opening the door 670, the ink container 1 can be pulled out from the main body 600, and maintenance such as replenishment and disposal of ink can be easily performed.

Next, the control circuit 645 of the inkjet recording device will be described with reference to FIG. In FIG. 8, the CPU 300 is a central processing unit that controls the inkjet recording device in this embodiment. The ROM 310 is a read-only memory that stores programs and control data necessary for the CPU 300 to operate. The RAM 305 is a rewritable memory that temporarily stores data and the like handled by the CPU 300 during program execution. The bus line 380 is a signal line including all the data, the address signal, and the control signal from the CPU 300. The interface circuit 315 mediates the input / output of data, address signals, control signals, and the like.

The pump control circuit 320 controls the operation of the supply pump 2 and the recovery pump 14, which will be described later, based on a command from the CPU 300. The solenoid valve control circuit 340 controls the operation of all solenoid valves such as the supply valve 33, the recovery valves 25, and 34, which will be described later, based on a command from the CPU 300.

The excitation source 370 creates an excitation signal based on the nozzle operating conditions, and drives a piezoelectric actuator (not shown) in the nozzle 6 described later. The recording signal source 360 creates a recording signal and print presence / absence information of each ink particle based on the input print data, stores the recording signal in the RAM 305, and applies the recording signal to the charging electrode 7 described later based on a command from the CPU 300. ..
Next, the operation of the inkjet recording apparatus in this embodiment will be described with reference to FIGS. 1 to 5.

FIG. 1 is a diagram showing an ink circulation system of an inkjet recording apparatus and a flight mode of ink particles in this embodiment. In FIG. 1, the inflow of ink into the ink container 1 and the outflow from the ink container 1 are performed through the ink supply flow path 21, the ink recovery flow path 22, and 23 connected to the ink container 1.

The ink supply flow path 21 includes an ink container 1, a supply pump 2 for pumping ink, a supply valve 33 for opening and closing the flow path, a pressure regulating valve 3 for adjusting the ink pressure, and a pressure gauge 4 for measuring the pressure of the supplied ink. There is a filter 5 for removing foreign matter, and the ink of the ink container 1 is supplied to the nozzle 6 at a predetermined pressure. The supply valve 33 is a two-way solenoid valve. The ink ejected from the nozzle 6 is continuously divided in synchronization with the excitation signal to form the ink particles 8.

Of the ink particles 8, the recording ink particles 8B used for printing are charged by applying a recording signal to the charging electrode 7, and then fly in a deflection electric field. The deflection electric field is formed between a pair of deflection electrodes, a high voltage electrode 9 to which a high voltage of 5 to 6 kV is applied, and a grounded ground electrode 10, and the ink particles 8 are charged according to the amount of charge thereof. Fly the route. The recording ink particles 8B used for printing fly beyond the gutter 11A and fly in a region sandwiched between the flight path 210 and the flight path 220 adhering to the object to be printed 12. Then, the recording ink particles 8B adhere to the printed matter 12 which is conveyed in a direction substantially perpendicular to the deflection direction, and print characters and the like composed of a two-dimensional matrix.

The dummy ink particles 8A fly in the flight path 200 and are incorporated into the gutter 11A. Further, the dummy ink particles 8C fly in the flight path 230 and are taken into the gutter 11B. As shown in FIG. 1, the gutters 11A and 11B are connected to the ink recovery channels 22 and 23. The ink recovery channels 22 and 23 include a filter 13 for removing foreign matter mixed during ink recovery, a recovery pump 14 for generating negative pressure in the gutters 11A and 11B, and recovery valves 25 and 34 for opening and closing the ink recovery flow path. It is provided, and the ink taken in by the gutters 11A and 11B is sent to the ink container 1 for recovery. The recovery valves 25 and 34 are electromagnetic two-way valves, which are opened during ink recovery and communicate with the ink recovery channels 22 and 23.

Here, a recording signal when printing a character composed of a two-dimensional matrix of 5 rows and 5 columns composed of 5 dots in the deflection direction and 5 dots in the transport direction, which is shown in FIG. 2, on the object to be printed 12. (Charging voltage) will be described with reference to FIG.

FIG. 3 is a diagram showing an example of a charging voltage pattern on ink particles of the inkjet recording apparatus in this embodiment. In FIG. 3, first, the wake formation mode 140 is performed before printing is performed. In the wake formation mode 140, dummy ink particles 8A and dummy ink particles 8C are alternately formed. The dummy ink particles 8A are charged with a charging voltage V0: 101 flying in the flight path 200. Further, the dummy ink particles 8C are charged with a charging voltage V6: 102 flying through the flight path 230. In the case of this embodiment, since the ink particles are generated at 70 kHz, the charging voltage V0: 101 and the charging voltage V6: 102 are alternately switched at 14.3 μs intervals and applied to the charging electrode.

After flying a predetermined number of dummy ink particles 8A and 8C, the printing mode 150 is switched to fly the recording ink particles 8B. In the print mode 150, the recording ink particles 8B are formed by applying the charging voltages V1 to V5 changed in five stages to the charging electrode 7 in synchronization with the generation timing of the ink particles 8, and is shown in FIG. Printing is performed on the first row (C1) having a 5-dot configuration.

The recording ink particles charged with the charging voltage V1 fly through the flight path 210, reach the printed object 12, and adhere to the R1 line of the two-dimensional matrix character. Further, the recording ink particles charged with the charging voltage V5 fly through the flight path 220, reach the object to be printed 12, and adhere to the R5 line of the two-dimensional matrix character. Similarly, the recording ink particles 8B charged with the charging voltages V2, V3, and V4 are set to adhere to the R2, R3, and R4 lines of the two-dimensional matrix character after flying in the region between the flight path 210 and the flight path 220. Has been done. In this embodiment, the charging voltage is set as V6> V5> V4> V3> V2> V1> V0.

From the second row (C2) onward, printing is performed by repeatedly applying the charging voltage changed in five stages to the charging electrode 7 four times in the same manner as in the first row (C1).

FIG. 4 shows an explanatory diagram of the flying state of the ink particles having the above configuration. As shown in FIG. 4, the recording ink particles 8B fly in the wake layer (air flow) previously formed by the wakes of the dummy ink particles 8A and 8C, and have air resistance regardless of the printing pattern. Becomes smaller. Further, the difference between the air resistance received by the recording ink particles 8B for printing in the first row (C1) and the second and subsequent rows (C2) can be reduced. As a result, the flight time in the static electric field and the flight time from the nozzle 6 to the object to be printed 12 are almost the same, and the print distortion due to the positional deviation in the deflection direction and the transport direction can be reduced.

As for the number of dummy ink particles 8A and 8C generated, it is sufficient to form a wake-up layer sufficient to reduce air resistance in the flight region of the recording ink particles 8B, and about 1000 or more dummy ink particles fly. However, it does not specify the number.

Further, the dummy ink particles may be a plurality of dummy ink particles to which the charging voltage V6: 102 is applied after the plurality of dummy ink particles to which the charging voltage V0: 101 is first applied as shown in FIG. The order may be reversed or it may be done randomly. Further, the charging voltages V0 and V6 may be changed within a range that can be recovered by the gutter 11.

Further, of the dummy ink particles 8A and 8C, only the dummy ink particles 8C may be used to form the wake-up layer.

Further, in the above embodiment, the dummy ink particles are deflected to the outside of the print area in the deflection direction (vertical direction: V6> V5, V0 <V1) in the print area of the object to be printed, but printing is performed in the deflection direction. Dummy ink particles may be made to fly out of the printed area (V5 to V1) where there is no printed object in the transport direction of the printed object. Further, when printing by the dummy ink particles is permitted on the printed object, the dummy ink particles are within the printing area (V5 to V1) in the deflection direction and at the timing when the printed object is also in the transport direction of the printed object. May be made to fly.

As described above, in this embodiment, the nozzle for ejecting the ink particles, the charging electrode for charging the ejected ink particles, and the deflection that deflects the flight direction of the ink particles when the charged ink particles fly in the electric field. The ink particles include electrodes, and the ink particles are composed of recording ink particles used for printing and dummy ink particles not used for printing, and the recording ink particles whose flight direction is deflected are adhered to the printed area of the object to be printed. A first dummy that is an inkjet recording device that performs printing, has a larger deflection amount than the recording ink particles adhering to the uppermost part of the print area of the object to be printed by the charged electrode and the deflection electrode, and flies out of the print area. A plurality of ink particles are generated at a timing earlier than that of the recording ink particles.

Further, by the charging electrode and the deflection electrode, the second dummy ink particles which have a smaller deflection amount than the recording ink particles adhering to the lowermost part of the print area of the object to be printed and fly out of the print area are recorded ink. The configuration is such that multiple particles are generated at an earlier timing than the particles.

Further, it is an inkjet recording method in which ink is ejected from a nozzle and continuously generated ink particles are charged and deflected so that the recording ink particles adhere to the print area of the object to be printed and printing is performed. Dummy ink particles are used in the area where the ink particles fly to create a flow of air, and the recording ink particles are made to fly in the flow.

Further, the air flow is generated by flying the dummy ink particles in front of the recording ink particles and in the vertical direction.

As a result, the recording ink particles fly in the wake layer formed by the wake of the dummy ink particles flying ahead of the recording ink particles, so that the recording ink particles do not depend on the flight pattern of the recording ink particles. Since the acting air resistance and the difference in air resistance between the recording ink particles can be reduced, printing distortion in the deflection direction of the recording ink particles and the transport direction of the printing target can be reduced.

1: Ink container 2: Supply pump, 6: Nozzle, 7 ... Charging electrode, 8 ... Ink particles, 8A, 8C: Dummy ink particles, 8B: Recording ink particles, 9, 10: Deflection electrodes, 11, 11A, 11B : Gutter, 14: Recovery pump, 21: Ink supply flow path, 22, 23: Ink recovery flow path

Claims (10)

The ink particles are provided with a nozzle for ejecting ink particles, a charging electrode for charging the ejected ink particles, and a deflection electrode for deflecting the flight direction of the ink particles when the charged ink particles fly in an electric field. It is an inkjet recording device that prints by adhering recording ink particles that are composed of recording ink particles used for printing and dummy ink particles that are not used for printing and whose flight direction is deflected into the printing area of the object to be printed. ,
A printing mode that generates a plurality of recording ink particles and prints composed of a plurality of dots, and a printing mode.
It has a wake formation mode that is executed before the print mode.
It has a control circuit for executing the wake formation mode, flying the dummy ink particles by a predetermined number, and then switching to the printing mode for flying the recording ink particles.
In the wake formation mode, the charging electrode and the deflection electrode have a larger deflection amount than the recording ink particles adhering to the uppermost part of the print area of the printed object, and the first dummy ink flies out of the print area. An inkjet recording device characterized by generating a plurality of particles. The inkjet recording apparatus according to claim 1.
Further, in the wake formation mode, the charging electrode and the deflection electrode have a second deflection amount smaller than that of the recording ink particles adhering to the lowermost part of the print area of the printed object, and the particles fly out of the print area. An inkjet recording device characterized by generating a plurality of dummy ink particles. The inkjet recording apparatus according to claim 2.
The wake-up formation mode is an inkjet recording apparatus characterized in that the first dummy ink particles and the second dummy ink particles are alternately generated. The inkjet recording apparatus according to claim 2.
The wake-up formation mode is an inkjet recording apparatus characterized in that one of the first dummy ink particles and the second dummy ink particles is continuously generated. It is an inkjet recording method in which ink is ejected from a nozzle and continuously generated ink particles are charged and deflected so that the recording ink particles adhere to the printing area of the object to be printed and printing is performed.
A printing mode that generates a plurality of recording ink particles and prints composed of a plurality of dots, and a printing mode.
It has a wake formation mode that is executed before the print mode.
The wake-up formation mode is executed to create an air flow by flying a predetermined number of dummy ink particles in the region where the recording ink particles fly, and then the printing mode is switched to the air flow. An inkjet recording method characterized by flying the recording ink particles. The inkjet recording method according to claim 5.
The inkjet recording method, characterized in that the air flow is generated by flying the dummy ink particles in front of and in the vertical direction of the recording ink particles. The inkjet recording method according to claim 5.
The air flow is generated by flying a plurality of first dummy ink particles having a larger deflection amount than the recording ink particles adhering to the uppermost part of the print area of the printed object and flying outside the print area. An inkjet recording method characterized by the fact that. The inkjet recording method according to claim 7.
The air flow further causes a plurality of second dummy ink particles that have a smaller deflection amount than the recording ink particles adhering to the lowermost part of the print area of the object to be printed and fly outside the print area. An inkjet recording method characterized by producing. The inkjet recording method according to claim 8, wherein the inkjet recording method is used.
An inkjet recording method characterized in that the first dummy ink particles and the second dummy ink particles are alternately flown. The inkjet recording method according to claim 8, wherein the inkjet recording method is used.
An inkjet recording method comprising continuously flying either one of the first dummy ink particles and the second dummy ink particles.

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