JP2001270111A - Method and apparatus for jetting liquid drop - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a quantity of liquid drops constant among nozzle openings irrespective of variations of characteristics of channels such as nozzle openings, etc., and characteristics of pressing means. SOLUTION: There are provided a driving signal-generating means 31 for generating a plurality of driving signals for making pressing forces of pressure generation chambers by piezoelectric vibrators 20-1 to 20-3 different in one discharge cycle, an ID data storage means 32 where ID data for specifying each of the nozzle openings are stored, a correction data storage means 33 where correction data for correcting the quantity of liquid drops of each nozzle opening are stored, and a driving signal-applying means 35 for reading out the correction data by the ID data of the nozzle openings which are to discharge liquid drops based on a liquid drop jet command signal and selectively outputting the driving signals to the piezoelectric vibrators 20-1 to 20-3 so as to jet a predetermined quantity of liquid. Each of the nozzle openings is specified by the ID data. Liquid drops are discharged while the quantity of liquid drops from each of the nozzle openings is adjusted by a driving energy to the piezoelectric vibrators 20-1 to 20-3 based on the correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for discharging a small amount of liquid as droplets from a nozzle opening.

[0002]

2. Description of the Related Art For example, an ink jet recording head capable of discharging a small amount of liquid to a target position with relatively high precision has been applied as a droplet ejecting means such as a printing apparatus or a micro dispenser.

On the other hand, the number of nozzle openings has been increased in order to improve the efficiency of ejection. However, the amount of liquid by one ejection between nozzle openings varies up to about ± 10%. Therefore, in special applications such as injecting a fixed amount of liquid into a predetermined area, it is necessary to adjust the amount of liquid by making the number of injections into the same area a plurality of times, which lowers the work efficiency. is there.

[0004]

In order to solve such a problem, it is conceivable to manufacture components constituting the injection means such as the nozzle opening, the pressure generation chamber, and the pressure generation means with higher accuracy. There is a problem that the cost rises sharply. The present invention has been made in view of such circumstances, and a purpose thereof is to be able to discharge a fixed amount of droplets from a plurality of nozzle openings, regardless of the accuracy of the ejection unit. It is to propose an injection method. It is another object of the present invention to provide a droplet ejecting apparatus suitable for carrying out the method.

[0005]

In order to achieve the above object, according to the present invention, a pressure generating chamber communicating with each of a plurality of nozzle openings arranged at a predetermined pitch, and A droplet is ejected by using a droplet ejecting head comprising a common liquid chamber for supplying the liquid to be ejected, and pressure generating means for changing the pressure of each pressure generating chamber to suck the liquid and discharge the liquid droplet from the nozzle opening. In the method of injecting,
Each nozzle opening is specified by ID data, and the droplet amount is ejected while adjusting the driving energy to the pressure generating means based on the correction data based on the correction data.

[0006]

According to the present invention, each nozzle opening is specified by ID data, and a drive signal is finely set in accordance with the amount of liquid discharged from each nozzle opening, so that variation in liquid amount between nozzle openings is corrected with high accuracy.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 shows an embodiment of a droplet ejecting apparatus, in which a carriage 1 equipped with droplet ejecting means described later is driven by a drive motor (not shown) housed in a mechanism chamber 3 of a frame 2 as indicated by an arrow A. The liquid in the tank 5 can be supplied to the injection means via the flexible liquid supply tube 4.

A stage 6 is provided below the frame 2 for supporting the object P to face the nozzle opening of the injection means.
Are provided on both sides of the guide member 8 of the base 7 so as to be movable in the moving direction of the carriage 1 (the direction indicated by the arrow B in the figure).

FIGS. 2A and 2B show one embodiment of the above-mentioned liquid ejecting means.
The recesses and through holes formed in the nozzle plate 10
Then, the other surface is sealed with the elastic plate 13 to form the pressure generating chamber 15, the liquid reservoir 16 communicating with the nozzle opening 11, and the liquid supply port 17 connecting the pressure generating chamber 15 and the liquid reservoir 16. The piezoelectric vibrator 20 is accommodated in the holder 19 so as to receive the extension displacement and the contraction displacement of the piezoelectric vibrator 20 in the elastic plate 13.

The piezoelectric vibrator 20 contracts in a charged state,
The other end is fixed to the base 21 in a state where the distal end is in contact with the elastic plate 13 so as to face the pressure generating chamber 15 at the time of transition from the charging state to the discharging state. In the drawing, reference numeral 22 denotes an introduction pipe for supplying a liquid to the reservoir 16 by the liquid supply tube 4, and reference numeral 23 denotes a flexible cable for supplying a drive signal to the piezoelectric vibrator 20.

FIG. 3 shows an embodiment of a discharge device. The discharge control means 30 outputs a discharge command at a predetermined period in accordance with the relative position between the discharge target and the nozzle opening of the discharge means. Driving signal generating means 31 for outputting a plurality of types of driving signals to be described later to the piezoelectric vibrator 20 as pressure generating means.
And ID data storage means 32 in the piezoelectric vibrators 20-1 to 20-3 related to the nozzle openings from which droplets are to be ejected.
In order to apply an optimal drive signal by referring to the data in the correction data storage unit 33, the switching units 34-1 to 3-3 are used.
Drive signal applying means 3 for outputting a signal for turning on 4-3
And 5.

As shown in FIG. 4, the drive signal generating means 31 outputs a plurality of signals, in this embodiment, three types of signals S1, S2, and S3 having different amounts of displacement of the piezoelectric vibrator 20 in one ejection cycle at a constant cycle. It is configured to output.

The drive signal S2 is a reference amount, for example, a liquid amount of a droplet generated by one ejection is a piezoelectric amount of a nozzle opening of 10 picoliters. The drive signal S1 is a liquid amount of a single droplet. Is applied to a piezoelectric vibrator with a nozzle opening of 10.5 picoliters, and the drive signal S3 is applied to a piezoelectric vibrator with a smaller liquid amount of one drop, for example, a nozzle opening of 9.5 picoliters. The driving signal S1 and the driving signal S3 are set to voltages V1 and V2 different from the driving voltage V2 of the reference driving signal S2. For this reason,
The drive energy applied to the piezoelectric vibrator can be adjusted, and even if there are variations in the flow path characteristics such as the nozzle opening, the piezoelectric constant of the piezoelectric vibrator 20, and the displacement characteristics,
By appropriately selecting any one of the drive signals S1 and S2, it is possible to discharge a droplet having substantially the reference liquid amount in one discharge.

When the driving signal is configured as a trapezoidal or triangular wave signal, the energy required for the piezoelectric vibrator to eject droplets is not only the voltage of the driving signal but also the rate of change of the voltage, That is, it can be adjusted by changing the voltage that increases or decreases per unit time.

The ID data storage means 32 stores ID data for specifying each of a plurality of nozzle openings provided on the nozzle plate 10 of the injection means.

The correction data storage means 33 stores data for selecting one of the drive signals S1, S2, S3 in which the liquid amount of the liquid droplet ejected at one time from the nozzle opening specified by the ID data becomes a reference value. It is stored and configured.

In this embodiment, the reference drive signal S1
Drive the piezoelectric vibrators 20-1, 20-2, and 20-3, respectively, and measure the liquid amount of each droplet. As a result, the liquid volumes of the droplets discharged from the nozzle openings by driving the piezoelectric vibrators 20-1, 20-2, and 20-3 are 10.5 picoliter, 10.0 picoliter, and 9.5, respectively. If it is determined that the pressure is picoliter, the correction data storage means 33 stores the drive signal S1 for the piezoelectric vibrator 20-1 and the drive signal S2 for the piezoelectric vibrator 20-2 in correspondence with the ID data of the nozzle openings. And the piezoelectric vibrator 20
-3 stores data instructing to apply the drive signal S3.

When the ejection command is input at the stage when the correction data for all the nozzle openings has been stored in this way, the ejection control means 30 activates the drive signal generation means 31 to drive the drive signal during one ejection cycle. The signals S1, S2, and S3 are output serially.

At the same time, the drive signal applying means 35 is operated, and the ID data storing means 32 and the correction data storing means 3 are operated.
3, the switching means 34-1 is turned on when the drive signal S1 is output, and the switching means 34-2 is turned on when the drive signal S2 is output.
Is turned on, and when the drive signal S3 is output, the switching means 34-3 is turned on.

As a result, the piezoelectric vibrator 20-1 generates energy weaker than the reference value, and the liquid amount when the reference signal S2 is applied is less than 10.5 picoliter.
A 0.0 picoliter droplet is applied to the piezoelectric vibrator 20-3.
Discharges a liquid droplet of 10.0 picoliters, which is larger than the liquid amount of 9.5 picoliters when the reference signal S2 is applied.
Picoliter droplets can be ejected.

As described above, when the carriage 1 and the stage 6 are driven to move the object P at the time when the ejection of the liquid to the predetermined location is completed, the ejection control means 30 outputs an ejection signal. The above steps are repeated.

In the above embodiment, one droplet is ejected in one ejection cycle. However, as shown in FIG. 5, the period is such that the meniscus does not interfere with each other due to the mutual drive signal. When the drive signals S1, S2, and S3 are set as one set, and this is repeated a plurality of sets within one ejection cycle,
Since the liquid amount from each nozzle opening can be adjusted to a value other than the reference value, the liquid amount within one ejection cycle can be finely adjusted.

In the above-described embodiment, an independent drive signal is applied to the pressure generating means in accordance with the amount of liquid in each nozzle opening. However, as shown in FIG. , And a plurality of driving signals A and B having different driving energies A-1 and B-1 to A-4 and B-
4 is generated at intervals at which the movement of the meniscus due to the mutual signal does not stop, and at which timing it is supplied to the piezoelectric vibrator is defined as mode 1 to mode 5,
Taking an example of a piezoelectric vibrator having a nozzle opening for discharging a reference amount of droplets, it is possible to adjust from 36 picoliters to 40 picoliters in increments of 1 picoliter.

That is, assuming that the standard amount is 38 picoliters, mode 5 is used for a piezoelectric vibrator having a nozzle opening that can discharge only 36 picoliters, and a piezoelectric vibrator having a nozzle opening that can discharge 40 picoliters is used. By adjusting the data of the correction data storage unit 33 so that the drive signal is applied in the mode 1, it is possible to correct the variation in the liquid amount between the nozzle openings.

Further, by dynamically selecting the plurality of modes, it is possible to adjust the amount of one drop to an arbitrary value while correcting the variation in the amount of liquid between nozzle openings.

Similarly, as shown in FIG. 7, a plurality of drive signals C having the same drive energy in one ejection cycle are generated at a constant cycle in which the movement of the meniscus due to the mutual signal is not stopped, in this embodiment, four drive signals are generated. The liquid amount can be adjusted by selecting the timing of application to the piezoelectric vibrator 20.

That is, when the next drive signal C2 is applied at the time (t1) when the time T0 until the meniscus by the immediately preceding droplet ejection is substantially flattened as in mode 2, FIG. As shown in (3), a droplet equivalent to the immediately preceding drive signal C1 is ejected. However, as in mode 3, the movement of the meniscus due to the immediately preceding droplet ejection goes to the pressure generating chamber side (t2). When the next driving signal C4 is applied, the kinetic energy of the meniscus after droplet ejection is used as shown in FIG. 8 (b), the meniscus largely moves, and as a result, the The amount increases.

In such a droplet ejecting apparatus, as shown in FIG. 9, the surface of the substrate 40 is divided by a bank material 41 into a fixed area, and a prescribed amount of a liquid dye 43 is applied to each of the divided areas 42. This is an optimal means for the purpose of forming a filter by evaporating the solvent after injection.

Further, in the above-described embodiment, a case has been described in which liquid droplets are supplied to the object to be coated. However, by using ink as a liquid, a predetermined image or character can be printed on a print medium with high quality. be able to.

In the above-described embodiment, droplets are ejected by changing the volume of the pressure generating chamber by the piezoelectric vibrator. However, a heating element is incorporated in the pressure generating chamber to vaporize the liquid. The same effect can be obtained by applying the present invention to a device that discharges a liquid by pressure during vaporization.

[0031]

As described above, in the present invention,
Each nozzle opening is specified by the ID data, and the droplet amount of each nozzle opening is ejected while adjusting the driving energy to the pressure generating means based on the correction data. The drive signal can be finely set according to the amount of liquid discharged from each nozzle opening specified by ID data, and droplets can be ejected while correcting variations in liquid amount between nozzle openings with high accuracy. .

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an injection device of the present invention.

FIGS. 2 (a) and 2 (b) are an assembly perspective view and a sectional view, respectively, showing an embodiment of an injection means used in the above-described injection device.

FIG. 3 is a block diagram showing an embodiment of the injection device of the present invention.

FIG. 4 is a diagram illustrating an example of a drive signal.

FIG. 5 is a waveform chart showing another embodiment of the present invention.

FIG. 6 is a waveform chart showing another embodiment of the present invention.

FIG. 7 is a waveform chart showing another embodiment of the present invention.

FIGS. 8A and 8B are diagrams for explaining a change in a droplet amount in the embodiment.

FIGS. 9A and 9B are a perspective view and a cross-sectional view, respectively, showing an example of an object to which a droplet ejecting apparatus according to the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 carriage 2 frame 3 liquid supply tube 5 tank 6 stage 10 nozzle plate 11 nozzle opening 12 flow path forming plate 13 elastic plate 15 pressure generating chamber 16 liquid reservoir 20, 20-1 to 20-3 piezoelectric vibrator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B05C 5/02

Claims (7)

[Claims] 1. A pressure generating chamber communicating with each of a plurality of nozzle openings arranged at a predetermined pitch, a common liquid chamber for supplying a liquid to be injected from the outside to the pressure generating chamber, and a pressure of each pressure generating chamber. In the method of ejecting liquid droplets using a liquid droplet ejecting head comprising liquid suction by changing the pressure and a pressure generating means for ejecting liquid droplets from the nozzle openings, each nozzle opening is specified by ID data, A droplet ejecting method for ejecting a droplet while adjusting a driving energy to the pressure generating means based on correction data on a droplet amount of each nozzle opening. 2. The droplet according to claim 1, wherein a period during which the driving energy for discharging the liquid to be ejected as droplets can be applied to the pressure generating means a plurality of times is set as one ejection cycle. Injection method. 3. The droplet ejecting method according to claim 1, wherein the liquid amount at the nozzle opening is adjusted to a predetermined value by applying the driving energy a plurality of times within the one ejection cycle. 4. A pressure generating chamber communicating with each of a plurality of nozzle openings arranged at a predetermined pitch, a common liquid chamber for supplying a liquid to be injected from outside to the pressure generating chamber, and a pressure of each pressure generating chamber. And a driving signal for changing the pressure of the pressure generating chamber by the pressure generating means, the discharging signal comprising one discharge cycle. A plurality of drive signal generation means, ID data storage means for storing ID data for specifying each of the nozzle openings, and correction data storage means for storing correction data for correcting the droplet amount of each of the nozzle openings Reading the correction data based on the ID data of the nozzle opening from which a droplet is to be ejected based on the droplet ejection command signal, and instructing the pressure generating means to eject a predetermined amount of liquid. And a drive signal applying means for selectively outputting a drive signal of the drive signal generating means. 5. The drive signal applying means selects a plurality of drive signals within one ejection cycle based on the ID data and the correction data and outputs the selected drive signals to the pressure generating means.
A liquid droplet ejecting apparatus according to claim 1. 6. The droplet ejecting apparatus according to claim 4, wherein the pressure generating chamber has an elastically deformable wall surface, and the wall surface is displaced by a piezoelectric vibrator. 7. The droplet ejection apparatus according to claim 4, wherein a heating element is stored in the pressure generating chamber, and the droplet is ejected by a vaporization pressure of the liquid to be ejected by the heating element.