JPH10250067A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer for forming a dot of suitable density by preventing discharge medium from being introduced from a second nozzle to a first nozzle. SOLUTION: The printer comprises a first pressure chamber in which a quantitative medium 22 is to be introduced, a second pressure chamber in which a discharge medium 21 is to be introduced, a first nozzle 6 communicating at one side with the first chamber and becoming at the other a first nozzle opening 6a, a second nozzle 4 communicating at one side with the second chamber and becoming at the other a second nozzle opening 4a, a first pressure applying means for applying pressure to the medium 22 in the first chamber to extrude the medium 22, and a second pressure applying means for applying pressure to the medium 21 in the second chamber to discharge the medium 21. In this case, the opening 4a is disposed adjacent to the opening 6a, and an opening length of a directed to the opening 6a of the opening 4a is larger than that of a direction perpendicular thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called two-liquid mixing type printer device in which a fixed amount medium and a discharge medium are mixed and ejected and adhered to a recording material for recording.

[0002]

2. Description of the Related Art In recent years, documents such as desktop publishing have been actively used in offices and the like. Recently, not only characters and figures but also color images such as photographs have been developed. There has been an increasing demand for outputting natural images together with characters and figures. Along with this, it is required to print a high-quality natural image, and gradation expression by halftone display is important.

A so-called on-demand type in which ink droplets are ejected from nozzles only when necessary during printing in accordance with a control signal in accordance with a recording signal and are adhered to a recording material such as paper or film to perform recording. In recent years, the printer device has been rapidly spreading because of the possibility of miniaturization and cost reduction.

As described above, various methods have been proposed for discharging ink droplets from nozzles.
A method using a piezo element or a method using a heating element is generally used. The former is a method in which pressure is applied to ink to discharge it by deformation of a piezo element. The latter method is a method in which the ink is heated and vaporized by a heating element and the ink is ejected at a pressure of bubbles generated.

Various methods have been proposed as methods for simulating the above-described halftone display by gray scale display using a printer apparatus for ejecting ink droplets. That is, the first method is to control the size of a droplet to be ejected by changing the voltage or pulse width of a voltage pulse applied to a piezo element or a heating element, and to express gradation by changing the diameter of a print dot. Can be

However, in the first method, if the voltage or pulse width applied to the piezo element or the heating element is too low, the ink will not be ejected, so that the minimum droplet diameter is limited. It has the disadvantage of being very difficult to express, especially at low concentrations. Therefore,
It is unsatisfactory to print out natural images.

As a second method, one pixel is constituted by a matrix of, for example, 4 × 4 dots without changing the dot diameter, and the gradation is expressed by a so-called dither method or the like in units of the matrix. There is a method of performing.

However, also in the second method, when one pixel is constituted by a 4 × 4 matrix, a density of 17 gradations can be expressed. For example, the dot density is the same as that of the first method. When printed, the resolution is reduced to 1/4, and the roughness is conspicuous, which is also unsatisfactory for printing out a natural image.

In order to clarify in principle the problems of the conventional printer apparatus which discharges only ink, the present inventors have proposed an ink and a transparent solvent as disclosed in Japanese Patent Application Laid-Open No. Hei 5-201024. A two-liquid mixing type printer apparatus is proposed in which a diluting liquid is mixed at a predetermined mixing ratio immediately before ejection to form a diluted ink, and the diluted ink is immediately ejected from a nozzle to adhere to a recording material and perform recording. I've been. Hereinafter, among such methods, the ink is used as a measurement medium, the diluent is used as a discharge medium, and the ink as a measurement medium is mixed with a diluent as a discharge medium to obtain diluted ink, and the discharge medium is discharged. A method of performing recording by using a carrier jet method is described. However, in the above-described printer apparatus, there is no problem even if the diluting liquid is used as the measurement medium and the ink is used as the ejection medium.

In such a printer of the carrier jet system, it is possible to control the density of the diluted ink droplets to be ejected and to change the density for each dot to be printed, thereby causing deterioration in resolution. It is possible to print out a natural image rich in intermediate gradations without any problem.

[0011] Such a two-liquid mixing type printer device has a first pressure chamber into which a quantitative medium is introduced, and a second pressure chamber into which a discharge medium is introduced. A first nozzle that communicates with the first pressure chamber and the other is a nozzle opening, and a second nozzle that communicates with the second pressure chamber and the other is a second nozzle opening, The first nozzle opening and the second nozzle opening are arranged so as to be adjacent to each other. Then, a predetermined amount of the fixed amount medium is transmitted from the first nozzle through the opening surface and oozes out toward the second nozzle, and is brought into contact with the discharge medium filled at the second nozzle opening, and the fixed amount is fixed. A printer device that discharges the discharge medium from the second nozzle to discharge the quantitative medium and the discharge medium as a mixed solution. That is, in this printer device, the ink concentration of the mixed droplet is changed for each dot by mixing a fixed amount of the diluting liquid or ink serving as the discharge medium while changing the amount of the ink or diluting liquid which becomes the measuring medium. To represent the gradation.

[0012]

In such a printer apparatus, first pressure applying means for applying pressure to a fixed amount medium in a first pressure chamber and pressure to a discharge medium in a second pressure chamber are applied. A second pressure applying means for applying a pressure to the quantitation medium in the first pressure chamber by the first pressure application means to allow the quantification medium to seep out from the first nozzle communicating therewith; , The second pressure applying means
By applying pressure to the discharge medium in the pressure chamber, the discharge medium is discharged from the second nozzle communicating therewith.

The first and second pressure applying means may expand and contract by changing the drive voltage to apply pressure to the first pressure chamber and the second pressure chamber.
A piezo element for applying pressure to the metering medium and the ejection medium filled therein is exemplified. In such a pressure applying means, a quantitative medium which oozes toward the first and second nozzles by the magnitude of the driving voltage, the pulse width, the timing of applying pressure to the first and second pressure chambers, and the like. And the amount of the ejection medium to be ejected is regulated.

Now, in order to perform the operation for discharging the discharge medium from the second pressure chamber, the reverse operation must be performed in advance by the second pressure applying means and kept in a standby state. No.

That is, it is necessary to draw the discharge medium into the second pressure chamber from the discharge medium supply chamber. However, at this time, there is also an operation that the ejection medium in the second nozzle is drawn into the pressure chamber. As a result, the meniscus of the ejection medium recedes from the second nozzle opening. The meniscus of the receded ejection medium is pulled again in the direction of the second nozzle opening by the surface tension, and returns to a position near the opening before the ejection medium is ejected from the second nozzle.

When the retracted meniscus returns to the nozzle opening, the meniscus does not necessarily stop immediately after reaching the nozzle opening. In fact, since the momentum is increasing in the process of returning, damped oscillation starts around the vicinity of the nozzle opening. When the vibration amount is large, a phenomenon occurs in which the ejection medium enters the first nozzle with excessive force.

When the ejection medium is ejected from the second nozzle, the meniscus of the ejection medium recedes by the amount of the ejected medium. At this time, the same phenomenon as described above occurs, and the ejection medium may enter the first nozzle in a process in which the retracted meniscus returns to the nozzle opening.

As described above, when the discharge medium enters the first nozzle, the discharge medium and the measurement medium are mixed, and the measurement medium is thinned. That is, the thinned quantitative medium is mixed with the ejection medium, and dot formation at a density lower than the predetermined ink density is performed.

In view of such circumstances, the present invention prevents a discharge medium from entering the first nozzle from the second nozzle in addition to the predetermined mixing / discharging operation, thereby forming dots having an appropriate density. It is an object of the present invention to provide a printer device capable of performing such operations.

[0020]

In order to achieve the above-mentioned object, a printing apparatus according to the present invention utilizes the property that the ejection medium is rounded by surface tension when the ejection medium protrudes from the opening of the second nozzle. The shape of the nozzle opening of No. 2 is such that the ejection medium does not enter the first nozzle from the second nozzle.

That is, the printer according to the present invention comprises:
A first pressure chamber into which the metering medium is introduced, a second pressure chamber into which the discharge medium is introduced, and a first pressure chamber in which one communicates with the first pressure chamber and the other serves as a first nozzle opening. A nozzle, a second nozzle having one communicating with the second pressure and the other being a second nozzle opening, and a first pressure application for applying a pressure to the fixed medium in the first pressure chamber to extrude the fixed medium. Means and the second
And a second pressure applying means for applying pressure to the discharge medium in the pressure chamber to discharge the discharge medium, wherein the second nozzle opening is arranged so as to be adjacent to the first nozzle opening. The opening length of the second nozzle opening in the direction toward the first nozzle opening is larger than the opening length in the direction orthogonal to the first nozzle opening. Then, the first pressure applying unit is caused to perform an extruding operation from a steady state, so that the quantitative medium is exuded from the first nozzle toward the second nozzle, and the quantitative medium is discharged near the tip of the second nozzle. After being brought into contact with the medium, the second pressure applying unit is caused to perform a discharging operation from a steady state, and the discharging medium is discharged from the second nozzle to mix and discharge the quantitative medium and the discharging medium.

The printer according to the present invention may be the following printer. That is, the printer device includes a first pressure chamber into which the fixed amount medium is introduced,
A second pressure chamber into which a discharge medium is introduced,
The first nozzle which communicates with the other pressure chamber and the other is the first nozzle opening
And a second nozzle, one of which communicates with the second pressure and the other of which is a second nozzle opening, and a first pressure for applying pressure to the quantitative medium in the first pressure chamber and extruding the quantitative medium And a second pressure applying means for applying pressure to the discharge medium in the second pressure chamber to discharge the discharge medium.
Is arranged so as to be adjacent to the first nozzle opening, and the first nozzle opening of the second nozzle opening is
Has a notch at a position opposite to the side adjacent to the nozzle opening. Then, the first pressure applying unit is caused to perform an extruding operation from a steady state, so that the quantitative medium is exuded from the first nozzle toward the second nozzle, and the quantitative medium is discharged near the tip of the second nozzle. After contacting the medium, the second
The pressure applying means performs the discharging operation from the steady state.
And discharges the discharge medium from the nozzles and mix-discharges the quantitative medium and the discharge medium.

As described above, the second nozzle opening of the printer device according to the present invention is the first nozzle opening of the second nozzle opening.
Of which the opening length in the direction toward the nozzle opening is larger than the opening length in the direction orthogonal thereto, or the side opposite to the side of the second nozzle opening adjacent to the first nozzle opening Has a notch at the position. That is, the shape of the second nozzle opening is such that the ejection medium is the second nozzle opening.
Utilizing the property of being rounded by surface tension when exiting from the nozzle, when the ejection medium emerges from the second nozzle, in the former case, in the direction orthogonal to the direction toward the first nozzle opening It overflows a lot, and in the latter case, it overflows in the notched direction. Therefore, in addition to the predetermined mixing and discharging operation, the discharging medium does not enter the first nozzle, and the discharging medium does not mix with the quantitative medium, so that it is possible to form dots of appropriate density. Become.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of a printer according to the present invention will be described in detail with reference to the drawings. However, here, an example of a print head of a so-called carrier jet type printer device that mixes and discharges ink while mixing the diluting liquid will be described, and an example of a print head having a plurality of nozzle sets will be described. As shown in FIG. 1, the print head mixes and discharges ink and a diluting liquid, and a pressure chamber unit 1 having two pressure chambers, a second piezo unit 2 corresponding to the two pressure chambers, and a first Piezo unit 3
It is mainly composed of

The pressure chamber unit 1 is for mixing and discharging the ink and the diluting liquid as described above, and as shown in an enlarged view in FIG. A plate-shaped orifice formed at a substantially central portion with a first inlet 6 communicating with the second inlet 5, a first nozzle 6 serving as a discharge port of the ink 22, and a first inlet 7 communicating therewith. The plate 8 and the pressure chamber side walls 9a,
9 b, 9 c, 9 d, 9 e are formed as partition walls, the second pressure chamber 10 serving as a flow path for the diluent 21, the first pressure chamber 11 serving as a flow path for the ink 22, and the diaphragm 12. Is done.

In the orifice plate 8, as shown in FIG. 2, the nozzle openings 6a and 4a of the first and second nozzles 6 and 4 face an opening surface 8a serving as a printing surface. One end of each of the first and second inlets 7 and 5 communicating with the first and second nozzles 6 and 4 is connected to the opening surface 8.
a facing the back surface 8b. Accordingly, the second inlet 5 and the second nozzle 4 pass through the orifice plate 8 as a whole, and the first inlet 7 and the first nozzle 6 also pass through the orifice plate 8 as a whole. The first and second nozzles 6 and 4 are formed such that the angle between their opening directions indicated by θ in FIG. 2 forms 45 °, and these are formed as a nozzle set.

Further, in the orifice plate 8, as shown in FIG.
4. A second supply chamber 13 having a substantially U-shaped cross section serving as a diluting liquid reservoir and a first supply chamber having a substantially U-shaped cross section serving as an ink reservoir so as to sandwich the first and second introduction ports 7 and 5 therebetween. 14 is formed such that its opening faces the back surface 8b opposite to the opening surface 8a serving as a printing surface.

At this time, the pressure chamber side walls 9a, 9b, 9c, 9 are formed as partitions on the back surface 8b side of the orifice plate 8.
d, 9e are laminated, and the pressure chamber side walls 9a, 9b,
The opening of the second supply chamber 13 and the opening of the second inlet 5 are connected by a portion where 9c, 9d, and 9e are not formed, and a second pressure chamber 10 serving as a flow path is formed. A first pressure chamber 11 serving as a flow path is formed by connecting the opening of the first supply chamber 14 and the opening of the first inlet 7.

Then, the pressure chamber side walls 9a, 9b, 9
The diaphragm 12 is formed on the layers c, 9d and 9e, and the first and second pressure chambers 11 and 10 are sealed.

The second piezo unit 2 includes a plate-shaped second laminated piezo element 15 in which a piezoelectric material and a conductive material are alternately laminated, and one end of the second laminated piezo element 15. And a second holder 17 for fixing the second support 16 on which the second laminated piezo element 15 is fixed to the pressure chamber unit 1. The same applies to the first piezo unit 3, in which one end of the first laminated piezo element 18 is fixed to the first support 19, and these are connected to the first holder 2.
0 is fixed to the pressure chamber unit 1.

The first and second laminated piezoelectric elements 18,
15, a piezoelectric material and a conductive material laminated in a direction perpendicular to the longitudinal direction of the first and second pressure chambers 11 and 10;
Alternatively, either one laminated in a direction parallel to the longitudinal direction may be used. The laminated piezo element has a characteristic of extending in the laminating direction when a voltage is applied.

For this reason, the former laminated piezo element expands in the longitudinal direction of the first and second pressure chambers 11 and 10 due to application of a voltage, and contracts in a direction perpendicular to the longitudinal direction. Therefore, this laminated piezo element does not apply pressure to the pressure chamber. Such a laminated piezo element is referred to as d
_This is referred to as a _31- mode laminated piezo element.

On the other hand, in the latter laminated piezo element,
When a voltage is applied, the first and second pressure chambers 11 and 10 extend in a direction orthogonal to the longitudinal direction, and apply pressure to the pressure chambers. Such laminated piezoelectric element is referred to as a laminated piezoelectric element of the d ₃₃ mode.

The second laminated piezo element 15 is disposed so as to face the second pressure chamber 10 with the diaphragm 12 interposed therebetween, and the first laminated piezo element 18 is also disposed on the diaphragm 12.
The first pressure chamber 11 is arranged to face the first pressure chamber 11.

Therefore, in the print head having the above-described configuration, the diluent 21 flows from the diluent tank (not shown) through the supply pipe and the supply groove (not shown) to the second supply chamber 1.
2 from which a second nozzle 4 communicates with a second inlet 5 through a second pressure chamber 10 as shown in FIG.
And the second nozzle opening 4 is filled with the diluent 21.
second meniscus D ₂ is formed in the vicinity of a.

The same applies to one ink 22.
The ink is supplied from a not-shown ink tank to a first supply chamber 14 through a supply pipe or a supply groove (not shown), and communicates therefrom through a first pressure chamber 11 to a first inlet 7 as shown in FIG. The first meniscus D ₁ is filled in the vicinity of the first nozzle opening 6 a by the ink 22 after being filled in the first nozzle 6.
Is formed.

Further, in this print head,
As described above, a plurality of nozzle sets each including the first nozzle 6 and the second nozzle 4 are arranged adjacent to each other. That is,
As shown in FIG. 3, when viewed from the opening surface 8a side of the orifice plate 8 of the print head, a plurality of nozzle sets including the opening portions 6a and 4a of the first and second nozzles are connected to the second nozzle opening portions 4a. The first nozzle openings 6a are arranged adjacent to each other such that they are adjacent to each other.

FIG. 4 is a cross-sectional view of the print head taken along a line AA ′ in FIG. 3. The orifice plate 8 has a second nozzle 4 connected to the second inlet 5. Are arranged adjacent to each other, and the plurality of second pressure chambers 10 communicated with these are also arranged adjacent to each other. Further, a plurality of second laminated piezo elements 15 facing the plurality of second pressure chambers 10 are also arranged adjacent to each other, one end of which is held by the above-described second support 16, and The body 16 is fixed to a second holder 17.

The print head has the second
A first supply pipe 32 for supplying, for example, the diluent 21 to the pressure chamber 10 and a second supply pipe 23 connecting the first supply pipe 32 to an external diluent tank (not shown) are also formed. The same configuration is also applied to the first nozzle 6 side of the print head.

Next, FIG. 5 shows a cross-sectional view of the orifice plate 8 cut in the vicinity of the first and second pressure chambers 11 and 10. The second supply chamber 13 is connected to a plurality of second pressure chambers 10. The second pressure chambers 10 are formed in corresponding positions with corresponding sizes, and these second pressure chambers 10 are connected to the second supply chambers 13, respectively. The second supply chamber 13 and the first supply pipe 32 They are connected by a first supply groove 24.

On the other hand, the first supply chamber 14 has a size corresponding to the plurality of first pressure chambers 11 and is formed at a corresponding position. These first pressure chambers 11 correspond to first supply chambers 14.
The first supply chamber 14 and the third supply pipe 25 are connected by a second supply groove 26.
At this time, the third supply pipe 25 is connected to an external ink tank and the first supply pipe 32 by a fourth supply pipe (not shown).

Next, FIG. 6 shows the print head viewed from the opening surface 8a side of the orifice plate 8. For example, the second inlet 5 is formed in the opening surface 8a side of the second pressure chamber 10.
The second nozzle 4 is communicated through the second pressure chamber 10, and the second laminated piezo element 15 is disposed on the opposite side of the second pressure chamber 10 from the second nozzle 4.

Accordingly, the second liquid from the diluent tank (not shown)
The diluent 2 supplied to the second supply chamber 13 via the supply pipe 23 and the first supply pipe 32 through the first supply groove 24
1 is supplied to each of the plurality of second pressure chambers 10 and is filled in the second nozzle 4 corresponding to each of the second pressure chambers 10 and communicating with the second inlet 5. Then, each second laminated piezo element 15 corresponding to each second pressure chamber 10
Is deformed to pressurize the second pressure chambers 10 respectively,
The diluent 21 is discharged from the second nozzles 4 communicating with the second pressure chambers 10 on the side opposite to the second laminated piezo element 15.

That is, a plurality of second laminated piezo elements 1
5 is deformed and pressurized to the plurality of second pressure chambers 10, the diluent 21 is discharged from the plurality of second nozzles 4 at once, and the selected second laminated piezo element 15 is deformed. Then, the diluent 21 is discharged from the selected second nozzle 4 corresponding to this.

This is the same on the first pressure chamber 11 side, and the first pressure chamber 11 has the first surface on the opening surface 8a side.
The first nozzle 6 communicates with the first pressure chamber 11 via the inlet 7 of the first pressure chamber 11, and the first laminated piezo element 18 is arranged on the opposite side of the first pressure chamber 11 from the first nozzle 6.

Accordingly, the fourth ink tank (not shown)
The ink 2 supplied to the first supply chamber 14 through the supply pipe 27 and the third supply pipe 25 through the second supply groove 26
2 is supplied to each of the plurality of first pressure chambers 11 and filled in the first nozzles 6 corresponding to the respective first pressure chambers 11 and communicating with the first inlet 7. Then, each first laminated piezo element 18 corresponding to each first pressure chamber 11
Are deformed to pressurize the first pressure chambers 11 respectively,
The ink 22 is ejected from the first nozzles 6 connected to the first pressure chamber 11 on the side opposite to the first laminated piezoelectric element 18.

That is, a plurality of first laminated piezoelectric elements 1
8 are deformed and pressurized to the plurality of first pressure chambers 11, the ink 22 is ejected from the plurality of first nozzles 6 at one time, and the selected first laminated piezo element 18 is deformed. Then, the ink 22 is discharged from the selected first nozzle 6 corresponding to this.

Next, the operation of the above-described printer will be described with reference to FIG. 7 showing a driving voltage waveform. Here, the first and second laminated piezo elements 18, 1
When using the laminated piezoelectric element of the so-called d ₃₁ mode as 5 described. First, as shown in FIG. 7A, at the time of standby before printing, and at the time shown in FIG. 7A, for example, 20 [V] is applied to the second laminated piezoelectric element 15 in advance.
Is applied, and as shown in FIG.
At the time indicated by (A) in FIG. 7, for example, 20 [V] is applied to the first multilayer piezoelectric element 18 in advance.

[0049] Incidentally, at this time, as shown in FIG. 8, the second nozzle opening 4a formed in the orifice plate 8, the second meniscus D ₂ is formed, the first nozzle opening 6a a first meniscus D ₁ is formed.

At the time of printing, based on signals from a head drive, a head feed control, a drum rotation control, and the like provided in the printer device, first, the ink 22 is pushed out from the first nozzle 6 to be exuded. FIG.
7B, the voltage of the first laminated piezo element 18 is gradually reduced to, for example, 5 [V] over 50 [μsec] from the time indicated by (B) to the time indicated by (C) in FIG. . Then, the first laminated piezo element 18 gradually expands in the longitudinal direction, and the first pressure chamber 11 is gradually pressurized via the diaphragm 12 as schematically shown in FIG. 6, an ink 22 is applied to the first nozzle opening 6
a to the vicinity of the second nozzle opening 4a,
With the diluent 21 of the nozzle 4.

Also, as shown in FIG.
(B) At the time point shown in (B), the first laminated piezo element 18
7A, the voltage of the second laminated piezo element 15 is applied for 10 [μsec] from the time indicated by (D) in FIG. 7A to the time indicated by (E) in FIG. 7A. And for example 0
Start lowering gradually to [V]. Then, the second laminated piezo element 15 starts to elongate in the longitudinal direction, the second pressure chamber 10 is pressurized via the diaphragm 12, and the internal pressure starts to be applied to the second nozzle 4. Then, as shown in FIG. 10, the diluent 21 is pushed out from the second nozzle opening 4a, and the mixed liquid 40 containing the ink is pushed out from the second nozzle opening 4a in such a manner as to be pushed by the diluent 21. Then, 0 [V] is applied over 10 [μsec] until the time indicated by (E) in FIG. 7A, which is later than the time indicated by (C) in FIG. 7B.
Lower gradually. That is, the first laminated piezo element 1
8 after the pushing operation of the ink 22 by the
The discharging operation of the laminated piezo element 15 is ended. Then, as shown in FIG. 10, the diluent 21 is pushed out from the second nozzle 4, and the mixed liquid 40 containing the ink is pushed out from the second nozzle 4 in a form pushed by the diluent 21.

Then, the voltage of the first laminated piezo element 18 is maintained for 50 [μsec] from the time point indicated by (C) in FIG. 7B to the time point indicated by (F) in FIG. 7B. Also, the voltage of the second laminated piezo element 18 is shown in FIG.
(A) From the point in time (E) to the point in time (H) in FIG. During this time, a constriction 41 occurs in the mixed solution 40 as shown in FIG. When this state is further continued, the mixed solution 40 and the diluent 21 separate as shown in FIG.
0 is discharged from the second nozzle 4, and the mixed solution 40 continues to fly in a spherical shape toward the recording material, and is adhered onto the recording material to perform recording.

Next, as shown in FIG.
(B) From the time point indicated by (F) in FIG. 7B to the time point indicated by (G) in FIG. 7B, the voltage is gradually returned to the original voltage over 150 [μsec]. Then, the first laminated piezo element 18 starts to contract, and the ink 22 in the first supply chamber 14 is removed from the first pressure chamber 1.
It is taken in 0 and returns to the state of FIG. FIG.
As shown in FIG. 7A, 150 [μsec] from the time indicated by (H) in FIG. 7A to the time indicated by (J) in FIG.
c] and gradually return to the original voltage. Then, the second laminated piezo element 15 starts to contract, the diluent 21 in the second supply chamber 13 is taken into the second pressure chamber 10, and returns to the state of FIG.

Here, the state of the diluent 21 in the second nozzle 4 will be described in more detail with reference to FIGS. 13 to 18 and FIG. 7A.

First, the diluent 21 is prepared as shown in FIG.
The liquid is ejected from the second nozzle 4 from the time indicated by (E) to the time indicated by (E) in the figure. Then, as shown in FIGS. 13 and 14, the second meniscus D in the second nozzle 4 is formed.
₂ retreats by the amount of the discharged diluent 21.

As shown in FIG. 15, the second meniscus D ₂ receding in FIG. 14 tends to return in the direction of the second nozzle opening 4a due to the surface tension indicated by the arrow in the figure. Thereafter, as shown in FIG. 16, the diluent returns to the nozzle opening 4a. At this time, as shown in FIG. 17, the returning diluent exerts a force to spread from the second nozzle opening 4a due to the returning momentum.

However, in this embodiment, as shown in FIG. 19, the shape of the second nozzle opening 4a has an opening length A toward the first nozzle opening 6a of the second nozzle opening 4a. Is formed in a shape larger than the opening length B in a direction orthogonal to the direction, for example, an elliptical shape. Or
As shown in FIG. 20, the shape of the second nozzle opening 4a has a cutout at a position opposite to the side of the second nozzle opening 4a adjacent to the first nozzle opening 6a. It is formed in a shape, for example, a semicircular shape. The shape of the second nozzle opening 4a utilizes the property that both liquids are rounded by surface tension, and the force of the diluting liquid 21 going in the direction of the first nozzle 6 is suppressed by surface tension. doing. Therefore, even if the diluent 21 overflows from the second nozzle 4, it does not go in the direction of the first nozzle 6.

Specifically, when the shape of the second nozzle opening 4a is elliptical as shown in FIG.
As shown in FIG. 1, the diluent 21 tends to extend in the minor axis direction indicated by the arrow X in the figure, so that the diluent 21 is prevented from going in the direction of the first nozzle 6. Also, in the case of a semicircular shape as shown in FIG. 20, as shown in FIG. 22, since it tends to extend in a direction in which the circle indicated by the arrow Y in the figure is cut, the first direction which is the opposite direction is used. Of the diluent 21 in the direction of the nozzle 6 is suppressed.

Further, from the time point indicated by (H) in FIG. 7A to the time point indicated by (J) in FIG. 7A, pulling of the second laminated piezo element 15 is performed, and the second supply chamber is drawn. The diluent 21 in 13 is drawn into the second pressure chamber 10. But,
At the same time, as shown in FIG. 14, the second meniscus D ₂ is also drawn into the second pressure chamber 10 and retreats. Again, as described above, the second meniscus D ₂ retracted in FIG. 14, as shown in FIGS. 15 to 17, the force to be to spread from the second nozzle opening 4a acts. For the sake of simplicity, the figure used to explain the period between the point indicated by (E) in FIG. 7A and the point indicated by (H) in the figure is used here, but the degree of meniscus retreat is not necessarily limited. They do not match.

However, in the present embodiment, the shape of the second nozzle opening 4a is formed in an elliptical shape shown in FIG. 19 or a semicircular shape shown in FIG. For this reason, as described above, even if the diluent 21 overflows from the second nozzle 4, the diluent 21 does not go toward the first nozzle 6 due to the surface tension that tends to round.

[0061] Incidentally, In more detail, the diluent 21 overflowing a maximum at 18, returns to the second nozzle 4, the second meniscus D ₂ is centered on the second nozzle opening 4a Makes a damped vibration. If there remains once second momentum meniscus D ₂ drawn into the second nozzle 4, a force that tries to enter again the first nozzle 6 as shown in FIG. 18.

However, as described above, in the present embodiment, the shape of the opening 4a of the second nozzle is formed into an elliptical shape shown in FIG. 19 or a semicircular shape shown in FIG. For this reason, as described above, even if the diluent 21 overflows from the second nozzle 4, the diluent 21 does not go toward the first nozzle 6 due to the surface tension that tends to round. FIGS. 7 (a) in the same is true for the second motion of the meniscus D ₂ in the case of FIG from time indicated by (E) (H).

Here, if the second nozzle opening 4a is formed in a circular shape as in the prior art, the diluent 21 that has returned thereafter returns as shown in FIG. Due to the momentum, it protrudes from the second nozzle opening 4a and starts overshoot. The overshoot diluent 21 enters the first nozzle 6 as shown in FIG. As a result, the diluent 21
Is mixed with the ink 22 in the first nozzle 6 and
, The dot density lower than the predetermined density is finally formed. What has been described above has been described from the time point indicated by (E) in FIG. 7A to the time point indicated by (H) in the figure, and from the time point indicated by (J) in FIG. 7A to the time point indicated by (D) in FIG. It happens in between and becomes a problem.

As described above, in the present embodiment, since the shape of the second nozzle opening 4a is elliptical or semicircular, even if the diluent 21 overflows from the second nozzle 4,
The diluting liquid 21 does not go in the direction of the first nozzle 6 due to the surface tension that tries to curl. That is, since the diluent 21 and the ink 22 do not mix except for the predetermined mixing and discharging operation, it is possible to form dots having an appropriate density.

The shape of the second nozzle opening 4a of the printer device according to the present invention is not limited to the above-mentioned elliptical shape, but rather the first nozzle opening 6a of the second nozzle opening 4a. Any shape can be used as long as the opening length in the direction toward is larger than the opening length in the direction orthogonal to this. For example, a rectangular shape shown in FIG. 23 or a rhombus shape shown in FIG. 24 can be used. In extreme cases, a shape shown in FIG. 25 can be used.

The shape of the second nozzle opening 4a is as follows:
The shape is not limited to the above-described semicircular shape, and any shape may be used as long as it has a notch at a position opposite to the side of the second nozzle opening 4a adjacent to the first nozzle opening 6a. . For example, any of the eclipse shapes shown in FIGS. 26 and 27 can be used, or, to be extreme, a slightly distorted shape as shown in FIG. 28. However, as can be said with respect to the shape shown in FIG. 28, in the case of using a multi-nozzle, it is desirable that all the second nozzles have a shape disturbed in the same direction in order to stabilize the ejection direction. .

As described above, the second nozzle opening 4a is
Even if the diluent 21 overflows from the second nozzle opening 4a,
The diluent 21 is shaped so as to suppress the force of the diluent 21 trying to spread to the first nozzle opening 6a side. Therefore, the diluent 21 does not enter the first nozzle 6.

When the present invention is applied to a so-called continuous-type printer which is not an on-demand type, the drive waveform of the second laminated piezo element 15 is devised so that the second nozzle 4 can be used. First nozzle 6
The diluent 21 can be prevented from being mixed. Incidentally, the on-demand type is a method in which dots are not formed in a portion having no density, and the continuous type does not exude a quantitative medium, but discharges a discharge medium even in a portion having no density. It is a method.

That is, as described above, the diluent 2 between the time point indicated by (E) and the time point indicated by (H) in FIG.
The overshoot from the first second nozzle 4 occurs. Therefore, as shown in FIG. 29, it is preferable to start pulling the second multilayer piezoelectric element 15 at the time shown by (H) in the figure, for example, 20 [μs] after the time shown by (E) in FIG. As a result, the overshoot of the diluent 21 does not need to be mixed into the first nozzle 6.

[0070] Further, as described above, during the time indicated by the time shown in FIG. 29 (J) (D), but it always diluent 21 is drawn into the second nozzle 4, the meniscus D ₂ Returns to the surface, overshoots, and enters the first nozzle 6. Therefore, as shown in FIG.
The second laminated piezo element 15 is pulled, for example, for 85 [μs] from the time point indicated by (H) in FIG. 29 to the time point indicated by (J) in FIG.
It is preferable that the pressing operation of the second multilayer piezoelectric element 15 be started at the time point shown in FIG. 29D after [μs]. As a result, the overshoot of the diluent 21 does not need to be mixed into the first nozzle 6.

Assuming that the pressing time from the time point indicated by (D) in FIG. 29 to the time point indicated by (E) in FIG. 29 is 10 μs, one cycle of the drive waveform of the second laminated piezoelectric element 15 is as follows.
The total is 125 [μs], and the operation is 8 [kHz].

The present invention can be applied to both on-demand type and continuous type. However, in the case of the on-demand type, since there is a cycle in which the ejection operation is not performed, the time from the time point shown in FIG. 29J to the time point shown in FIG.
35 [μs], and the diluent 21 is likely to be mixed into the first nozzle 6.

As described above, the diluting liquid 21 that has receded into the second nozzle 4 due to the pushing operation of the second laminated piezo element 15
When the second piezo element 15 is overshooted and mixed into the first nozzle 6 when returning,
Should be started. Further, when the diluting liquid 21 drawn into the second nozzle 4 by the pulling operation returns, it overshoots and mixes into the first nozzle 6 before returning to the second laminated piezoelectric element 15. , Ie, the discharge operation of the diluent 21 may be started.
This can prevent the diluting liquid 21 from being mixed with the ink 22 in the first nozzle 6.

[0074]

As is clear from the above description, in the printer according to the present invention, the first pressure applying means is caused to perform the pushing operation from the steady state, and the first pressure is applied from the first nozzle to the second nozzle. After the quantitation medium is oozed toward the medium and the quantitation medium is brought into contact with the ejection medium near the tip of the second nozzle, the second pressure applying unit is caused to perform the ejection operation from a steady state, In a printer device that discharges a discharge medium and mixes and discharges a fixed amount medium and a discharge medium, the shape of the second nozzle opening is adjusted by utilizing the property that the discharge medium is rounded by surface tension when it comes out of the second nozzle. Since the shape is long in the direction toward the first nozzle opening or has a notch on the side opposite to the direction of the first nozzle opening, when the ejection medium comes out of the second nozzle,
In the former case, a large amount overflows in a direction perpendicular to the direction toward the first nozzle opening, and in the latter case, a large amount overflows in a cutout direction. Accordingly, the ejection medium does not enter the first nozzle, and the ejection medium does not mix with the fixed amount medium.

Therefore, the printer according to the present invention does not mix the discharge medium with the fixed amount medium except for the predetermined mixing and discharging operation, so that dots of an appropriate density can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part showing an example of a print head of a printer device to which the present invention is applied.

FIG. 2 is an enlarged schematic cross-sectional view of a main part of the vicinity of an orifice plate of an example of a print head of the printer device.

FIG. 3 is a plan view showing an example of a print head of the printer device.

FIG. 4 is a cross-sectional view illustrating an example of a print head of the printer device.

FIG. 5 is a sectional view showing an orifice plate of an example of a print head of the printer device.

FIG. 6 is a plan view schematically showing an example of a print head of the printer device.

FIG. 7 is a diagram showing a driving waveform of an example of a driving method of the printer device.

FIG. 8 is a cross-sectional view schematically showing an operation of the print head of the printer device at the time of printing, in which the first and second meniscuses are formed on the first and second nozzles. FIG.

FIG. 9 is a cross-sectional view schematically showing a printing operation of a print head of the printer in the order of operation, and schematically showing a state in which ink is mixed with a diluent of a second nozzle.

FIG. 10 is a cross-sectional view schematically illustrating a printing operation of the print head of the printer device in the order of operation, in which a mixed solution of a diluent and ink is formed.

FIG. 11 is a cross-sectional view schematically illustrating an operation of the print head of the printer device during printing in the order of operation, and schematically illustrating a state in which the mixed solution has constricted.

FIG. 12 is a cross-sectional view schematically showing a printing operation of a print head of the printer device in the order of operation, and schematically showing a state in which a mixed solution is discharged from a second nozzle.

FIG. 13 is a cross-sectional view schematically showing a printing operation of a print head of the printer device in an operation order, and schematically showing a state in which the mixed solution flies as spherical droplets.

FIG. 14 is a cross-sectional view illustrating a state of a diluting liquid in a second nozzle of the print head of the printer apparatus, in which a meniscus of a discharge medium in the second nozzle is retracted.

FIG. 15 is a cross-sectional view illustrating a state of a diluting liquid in a second nozzle of the print head of the printer device, in which a meniscus of a discharge medium in the second nozzle is retracted and then returned. It is.

FIG. 16 is a view showing a state of a diluent in a second nozzle of the print head of the printer apparatus, in which a meniscus of a discharge medium in the second nozzle retreats and returns to an opening. FIG.

FIG. 17 is a cross-sectional view showing a state of a diluent in a second nozzle of the print head of the printer apparatus, and showing a state in which a meniscus of a discharge medium in the second nozzle slightly protrudes from an opening. is there.

FIG. 18 illustrates an operation of the print head of another printer during printing, in which the diluent in the second nozzle protrudes from the second nozzle opening and enters the first nozzle. FIG.

FIG. 19 is a plan view showing shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 20 is a plan view illustrating shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 21 is a plan view showing a state in which a diluent overflows from a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 22 is a plan view illustrating a state in which a diluent overflows from a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 23 is a plan view showing the shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 24 is a plan view showing the shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 25 is a plan view showing the shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 26 is a plan view showing the shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 27 is a plan view showing shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 28 is a plan view showing shapes of a first nozzle opening and a second nozzle opening of a pudding head of a printer apparatus to which the present invention is applied.

FIG. 29 is a diagram illustrating a driving waveform of an example of a driving method of a continuous type printer device to which the present invention is applied.

[Explanation of symbols]

4 2nd nozzle, 6 1st nozzle, 10 2nd pressure chamber, 11 1st pressure chamber, 15 2nd laminated piezo element, 18 1st laminated piezo element, 21 diluent, 22
ink

Claims (2)

[Claims] 1. A first pressure chamber into which a metering medium is introduced,
A second pressure chamber into which a discharge medium is introduced,
Of the first nozzle which communicates with the pressure chamber of
And a second nozzle, one of which communicates with the second pressure and the other of which is a second nozzle opening, and a first pressure for applying pressure to the quantitative medium in the first pressure chamber and for pushing out the quantitative medium Applying means for applying pressure to the discharge medium in the second pressure chamber to discharge the discharge medium, wherein the second nozzle opening is adjacent to the first nozzle opening. And the opening length of the second nozzle opening in the direction toward the first nozzle opening is made larger than the opening length in the direction orthogonal to the first nozzle opening. After the extruding operation is performed from the state, the quantitative medium is exuded from the first nozzle toward the second nozzle, and the quantitative medium is brought into contact with the ejection medium near the tip of the second nozzle, and then the second medium is discharged. The pressure application means performs the discharging operation from the steady state, and the second nozzle Printer apparatus characterized by mixing and discharging the discharge medium and metering medium by ejecting et discharge medium. 2. A first pressure chamber into which a metering medium is introduced,
A second pressure chamber into which a discharge medium is introduced,
The first nozzle which communicates with the other pressure chamber and the other is the first nozzle opening
And a second nozzle, one of which communicates with the second pressure and the other of which is a second nozzle opening, and a first pressure for applying pressure to the quantitative medium in the first pressure chamber and extruding the quantitative medium Applying means for applying pressure to the ejection medium in the second pressure chamber to eject the ejection medium, wherein the second nozzle opening is adjacent to the first nozzle opening. The second nozzle opening has a notch at a position opposite to the side adjacent to the first nozzle opening, and is pushed out of the first pressure applying means from a steady state. After the operation is performed to cause the quantitation medium to seep out from the first nozzle toward the second nozzle and bring the quantitation medium into contact with the ejection medium near the tip of the second nozzle, the second pressure application means In the steady state, and ejects the ejection medium from the second nozzle. Printer apparatus characterized by mixing and discharging the discharge medium and metering medium by.