JPH10119280A - Liquid ejecting head and liquid ejecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control crosstalk phenomena, and eject ink stably even in the case of high frequency by the construction for supplying ink by a plurality of various shape nozzles for one heater, and where the various configured nozzles are adjacent to each other at the boundary of each bank of heaters. SOLUTION: A first nozzle 11a of a heater 11 is made relatively larger than a second nozzle 11b in the nozzle width W1 , i.e., to have a smaller flow resistance. Also, a fourth nozzle 12b of a heater 12 adjacent the nozzle 11a is made relatively smaller than a third nozzle 12a in the nozzle width W2 , i.e., to have a greater flow resistance. Accordingly, even when one component of bubble pressure of the heater 11 is transmitted to he adjacent fourth nozzle 12b along the V direction of arrow through a first common liquid chamber 6L, a large flow resistance of the fourth nozzle 12b makes influences small. In this way, a crosstalk phenomena can be suppressed so that ink can be ejected stably even in the event of high frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid discharge head and a liquid discharge apparatus that discharges liquid using the liquid discharge head.

[0002]

2. Description of the Related Art Among liquid ejecting apparatuses, an ink jet recording apparatus ejects ink as fine droplets from nozzles to record characters and figures, and is excellent as a means for outputting high-definition images and high-speed printing. Has advantages. Especially,
A method using a bubble (bubble) pressure generated by an electrothermal transducer (hereinafter, referred to as a heater) or the like, a so-called thermal ink jet recording method (Japanese Patent Publication No. 61-59911-4), requires a smaller apparatus and a higher image density. It has features such as ease.

FIG. 1 is an exploded perspective view showing one embodiment of such a conventional thermal ink jet head. The head shown in FIG. 1 is a so-called side shooter type head in which a heater 1 and an orifice 2 are provided to face each other.

As shown in FIG. 1, a plurality of heaters 1 are arranged in a row on a substrate 3, and a nozzle 4 as an ink supply path for supplying ink corresponds to an arrangement portion of each heater 1. It is formed. The plurality of nozzles 4 are constituted by a plurality of nozzle walls 5 formed in parallel. The nozzle 4 is closed at one end near the heater 1 and opened to the common liquid chamber 6 at the other end. The common liquid chamber 6 communicates with a supply port 7 for receiving ink from an ink tank (not shown). Further, an electrode wiring (not shown) for sending an electric signal to the heater 1 is provided on the substrate 3. Orifices 2 are formed at positions corresponding to the plurality of heaters 1 arranged in a row on the nozzle plate member 8 joined to the substrate 3 as described above.

FIG. 2 is an enlarged view showing the vicinity of the heater in FIG. 1, (a) is a plan view, and (b) is a schematic sectional view taken along line AA in (a).

[0006] As shown in FIG.
Is connected to the common liquid chamber 6 on the one hand and to the heater 1 on the other hand.

According to such a configuration, by reducing the size of the heater, the orifice, and the nozzle,
An ink jet head that ejects droplets of about 4 to 10 pl suitable for an image of 1,200 dpi and records a high-definition image can be created. In particular, in the method disclosed in Japanese Patent Application Laid-Open No. H10-10940, in which the nozzle height h is reduced and bubbles are communicated with the atmosphere to discharge liquid, minute droplets can be discharged stably.

Here, in the configuration shown in FIGS. 2A and 2B, if the nozzle is made smaller (especially, the nozzle height h is made smaller), the cross-sectional area of the opening of the nozzle becomes smaller, so that the flow resistance becomes smaller. Increase. This obstructs the flow of so-called refill, which replenishes ink lost by ejection from the liquid chamber, and causes a reduction in the frequency of repeated ejection of the heater. In particular, when forming an image with microdroplets,
In order to maintain the printing speed per sheet, ejection must be performed at a higher frequency, so that a situation that causes an increase in flow resistance is serious.

Therefore, a method of widening the cross-sectional area of the nozzle by widening the width W of the nozzle is considered.

[0010]

However, FIG.
As shown in (b), when the nozzle width W is increased, the amount of the ejection power generated by the heater that escapes in the direction V perpendicular to the ejection direction H increases, and the ejection speed and ejection amount of the droplets decrease. Image quality deteriorates. Further, the component in the V direction is a direction opposite to the flow of the ink refill, and adversely affects the refill.

The component in the V direction propagates to the adjacent nozzle as a V 'component as shown in FIG.
This causes a so-called crosstalk phenomenon, which adversely affects ink ejection.

On the other hand, JP-A-5-116317 mentions the stability of ejection and high-frequency driving, but does not consider the influence of the crosstalk phenomenon occurring between adjacent nozzles.

As a flow path structure having such a configuration, a head having a configuration capable of replenishing ink for one heater from two directions has been proposed.

However, in the head having such a configuration, since the flow resistances in the plurality of nozzles as the ink flow paths are all set to the same value, the flow of the ink refill may be hindered by the component in the V direction. At present, however, the crosstalk phenomenon has not yet been effectively suppressed.

An object of the present invention is to provide a liquid discharge head capable of suppressing a crosstalk phenomenon and stably discharging a liquid such as ink even at a high frequency.

It is another object of the present invention to provide a liquid discharge apparatus capable of producing a high-definition image by high-speed printing using the above-described liquid discharge head.

[0017]

A typical requirement of the present invention to achieve the above object is as follows.

[0018] At least one electrothermal converter provided to face a discharge port for discharging droplets, at least two liquid supply paths for supplying liquid to the electrothermal converter, Wherein the at least two liquid supply paths, which are to supply liquid to the same electrothermal transducer, have different flow resistances in the respective liquid supply paths.

Alternatively, each of the liquid supply paths has a different shape from each other.

Alternatively, the electrothermal converter is composed of at least two groups, the first group including a first liquid supply passage connecting the first liquid chamber and the electrothermal converter, And a second liquid supply path connecting the second liquid chamber and the electrothermal transducer and having a larger flow resistance than the first liquid supply path. A second group includes the first liquid chamber and the second liquid supply path. A third liquid supply path that communicates with the electrothermal converter; a fourth liquid supply path that connects the second liquid chamber and the electrothermal converter and has a smaller flow resistance than the third liquid supply path. A liquid ejection head including a liquid supply path.

Alternatively, the discharge ports are constituted by a plurality of ports, are arranged in rows, and the first liquid supply passages of the first group of the electrothermal transducers and the first liquid supply paths of the second group are provided. 3 liquid supply paths are arranged on one side with respect to the row of discharge ports, and the second liquid supply paths of the first group and the second liquid supply paths
A liquid discharge head, wherein the fourth liquid supply path of the group is arranged on the other side with respect to the row of the discharge ports.

Alternatively, a liquid ejection head in which the electrothermal transducers belonging to the first group and the electrothermal transducers belonging to the second group are alternately arranged along the rows of the ejection ports. .

Alternatively, a liquid discharge head in which flow resistances of adjacent liquid supply paths are alternately different.

Alternatively, a liquid discharge head in which the first liquid chamber and the second liquid chamber communicate with each other.

Alternatively, there is provided a liquid discharge head for discharging the liquid from the discharge port to the outside by using the pressure of bubbles formed in the liquid by the electrothermal transducer,
A liquid discharge head in which the bubble and the outside air communicate with each other in the vicinity of the discharge port in a state where the pressure in the bubble is lower than the outside air pressure.

Alternatively, the liquid is a liquid discharge head in which the liquid is ink.

Alternatively, there is provided a liquid discharging apparatus for discharging the liquid using the above-described liquid discharging head.

According to the characteristic configuration of the present invention, since a plurality of liquid supply passages are provided corresponding to one electrothermal converter, some components of the bubbling pressure at the time of discharging the liquid replenish the liquid. It does not work only in the obstructing direction, so that the loss of the ejection force can be suppressed. In addition, since the flow resistances of the at least two liquid supply paths in relation to supply the liquid to the same electrothermal transducer are different from each other, the liquid can be smoothly replenished through the liquid supply path having a relatively small flow resistance. In addition to the above, it is possible to reduce the influence of the bubbling pressure from other electrothermal converters through the liquid supply path having a relatively large flow resistance, and to suppress the crosstalk phenomenon effectively.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

[First Embodiment] FIG. 4 is an exploded perspective view showing a first embodiment of the liquid discharge head of the present invention, and FIG.
FIG. 5 is an enlarged schematic plan view showing the vicinity of the heater shown in FIG. 4. 4 and 5, the same components as those of the conventional head shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description of those components is omitted. I do.

The liquid ejection head according to this embodiment is of a so-called side shooter type, like the conventional head, but has two rows of orifices extending in a staggered manner extending in parallel with each other. The heaters 11, 12, 13, and 14 corresponding to these orifices are also arranged in a staggered manner. The heaters 11, 13 belong to the same row, and the heaters 12, 14 belong to another same row.

The heater 11 is provided at the bottom of one end of the first nozzle 11a having a nozzle width W1. One end of the first nozzle 11a communicates with the nozzle 11a,
The nozzle 11a extends along the length direction of the nozzle 11a.
a second nozzle 11b having a nozzle width narrower than the nozzle width a
Is provided. The other end of the first nozzle 11a communicates with the first common liquid chamber 6L, and the second nozzle 1a
1b communicates with the second common liquid chamber 6R at the end remote from the heater 11. Such a first nozzle 1
Since 1a and the second nozzle 11b have different nozzle widths,
The flow resistance is also set to be different.

The heater 1 adjacent to the heater 11
2 is provided at the bottom of one end of the third nozzle 12a having a nozzle width W2, and communicates with the third nozzle 12a at one end of the third nozzle 12a. A fourth nozzle 12b having a nozzle width narrower than the nozzle width of the nozzle 12a along the length direction is provided. The third nozzle 12a communicates with the first common liquid chamber 6L at the other end, and the fourth nozzle 12b
At the end remote from the second liquid chamber 6, it communicates with the second common liquid chamber 6R. Since the third nozzle 12a and the fourth nozzle 12b have different nozzle widths, they are set to have different flow resistances.

Here, the arrangement relationship of the liquid supply passage between the heater 11 and the heater 12 adjacent thereto will be described.

As described above, the first nozzle 11a of the heater 11 has a larger nozzle width W1 than the second nozzle 11b and therefore has a smaller flow resistance. The nozzle width of the fourth nozzle 12b is relatively smaller than that of the third nozzle 12a, and therefore, the flow resistance is large. Even if one component of the bubbling pressure of the heater 11 propagates through the first common liquid chamber 6L to the fourth nozzle 12b of the adjacent heater 12 along the direction of arrow V in FIG. Since the flow resistance is large, it is less affected.

The relationship between the heater 13 and the heater 14 is the same as the relationship between the heater 11 and the heater 12 described above.

The above-mentioned two common liquid chambers 6L and 6L
R may be independent of each of the liquid supply paths described above, or may be the same connected liquid chamber.

In this embodiment, basically, one heater can be efficiently replenished with liquid from the common liquid chamber via two liquid supply passages, so that high-frequency discharge is possible. Further, since the flow resistance of one liquid supply path is larger than the flow resistance of the other liquid supply path, the escape of the discharge force to the liquid supply path having a large flow resistance is reduced.

In this embodiment, as shown in FIG.
When the ejection pulse is applied to the heaters 11 and 13 at the same time, and the ejection pulse is applied to the heaters 12 and 14 after a delay time, the ejection force of the heater 11 from the nozzle 11a in FIG.
The component that has escaped in the direction indicated by the arrow V in FIG.
The heaters 12 and 13 are affected through the second nozzle 12b and the nozzle 13a of the heater 13 adjacent thereto.
However, since the flow resistance of the nozzle 12b is high and the position of the nozzle 13a is considerably far from the heater 11,
Before reaching 2, 13, the effect is attenuated and is not a problem. In addition, in such a delicate nozzle, there is a concern that the nozzle may be clogged by dust in the ink. However, according to this configuration, the ink is supplied to the heater from two directions. Even if it becomes clogged, it is possible to continue discharging.

In this embodiment, the flow path resistance is made different by making the width and length of the nozzle connected to one heater different. However, the fluid height is changed by providing the nozzle height and the sectional area or the fluid resistance element. The resistances may be different. Further, the heaters may be arranged not in a staggered shape but in a straight line.

Further, although the position of the supply port is also on the extension of the heater row in FIG. 4, an elongated supply port may be arranged in parallel with the heater row, facing the nozzle.

Next, a method for manufacturing the liquid discharge head according to this embodiment will be described. To manufacture a liquid ejection head, a solid layer serving as a nozzle as a flow path is formed on a substrate, a resin layer is formed around and on the solid layer, the solid layer is removed, and a nozzle is formed. A method of forming an orifice as an ink discharge port at a position of the layer facing the heater on the substrate can be used. Here, the nozzle and the orifice formed a pattern using a photocurable resin as a mold. The size of the heater is set to 26 μm × 26 μm, and 42
64 pieces were arranged at a pitch of μm. Orifice thickness t ₁
Was 10 μm and the orifice diameter was 18 μm. The thickness t _{2 of the} nozzle portion is 10 μm, and the length L ₁ of the nozzle 11a is 20.
μm, width W ₁ = 18 μm, length L _{2 of} nozzle 12a = 4
0 μm and width W ₂ = 10 μm. This head was driven at a frequency of 10 kHz, but could discharge normally.

[Second Embodiment] FIG. 7 is a schematic plan view showing a liquid discharge head according to a second embodiment of the present invention.

This embodiment is characterized in that, of the two nozzles,
A portion of one of the nozzles has a constriction 11c, 12c. . . Is provided. According to this configuration, even if the power in the initial stage of bubbling in the heater attempts to escape in the nozzle direction, a strong vortex is formed in the constricted portion due to the speed of the flow, and energy is lost. On the other hand, the replenishment flow of the ink is more gentle, so that the energy is not lost even in the constricted portion. If the length of the constricted portion is sufficiently short, the flow resistance is small, so that the influence is small. As a result, it is possible to provide a liquid discharge head that can be driven at a high frequency and has little crosstalk.

In the present embodiment, unlike the first embodiment, the heaters 11, 12,. . . Are arranged in a line, but if the nozzle has a configuration in which a constricted portion is provided in a part of the nozzle, a configuration in which the heaters are arranged in two lines in a staggered manner is employed as in the first embodiment. May be.

Third Embodiment FIG. 8 is a schematic plan view showing a third embodiment of the liquid discharge head of the present invention, and FIG.
9 is a graph for explaining the driving of the head shown in FIG.

In the present embodiment, unlike the first embodiment in which the heaters are arranged in a staggered manner, a plurality of heaters having the same nozzle are continuously arranged and have the same shape, but have the same orientation. A plurality of heaters having different nozzles are sequentially arranged, and the former group (block 1) of heaters 11
To 13 and the latter group (block 2) of heaters 14 to 16
It is characterized in that it belongs to another nozzle row. This configuration is effective when it is desired to simultaneously drive a group of continuous heaters, that is, heaters belonging to the blocks 1 or 2.

That is, as shown in FIG.
After the ejection pulse is applied to the heaters belonging to block 2, after a predetermined delay time, the ejection pulses are applied to the heaters belonging to block 2.

Generally, when driving is performed in such a manner,
Among the discharge powers of the heaters belonging to block 1, the component in the direction of arrow V shown in FIG. 8 increases by the number of nozzles, and crosstalk also increases.

However, according to the configuration shown in FIG. 8, in order for the above-described component in the direction of the arrow V escaping from the block 1 to affect the heater belonging to the block 2, the component must pass through a narrow nozzle having a large flow resistance. Therefore, in practice, crosstalk from the block 1 to the block 2 can be efficiently suppressed, and good liquid ejection can be performed.

In this embodiment, block 1 or block 2
Although only three heaters are shown as belonging to each block, the number of heaters belonging to each block may be, for example, 16, and the 16 heaters may be driven simultaneously as one unit.

The configuration of the head to which the present invention can be applied is not limited to the scope of the above-described embodiment. For example, as a material for forming the orifice, a photosensitive resin,
Plating substrates with orifices formed by electroforming, thin resin tapes such as polyimide, and moldable resins (for example, PS
F) etc. can be used. The orifice can be formed by patterning with light, ashing with UVO ₃ , patterning with an excimer laser, or the like.

The overall configuration of such a liquid discharge head will be described with reference to FIGS. 10 (a) and 10 (b).

FIGS. 10A and 10B are diagrams showing a schematic configuration of an example of the liquid discharge head of the present invention.
0 (a) is a perspective view showing the appearance, and FIG. 10 (b) is a cross-sectional view along the line AA in FIG. 10 (a).

In FIG. 10, reference numeral 3 denotes a Si element substrate in which a heater as an electrothermal conversion element and a discharge port are formed by a thin film technique. This element substrate 3 has a structure shown in FIG.
As shown in (a), a plurality of discharge ports 2 arranged in two rows are provided in a staggered manner. The element substrate 3 is bonded and fixed to a part of the support member 102 processed into an L shape. Similarly, a wiring board 104 is fixed on the support member 102,
The wiring portion of the wiring substrate 104 and the wiring portion of the element substrate 3 are electrically connected by bonding. The support member 102 is formed of an aluminum material from the viewpoint of cost, workability, and the like. The mold member 103 has a part of the support member 102 inserted therein to support the support member 102 and a liquid supply path 107 formed therein.
This is a member for supplying a liquid (for example, ink) from a liquid storage unit (not shown) to a discharge port provided in the above-mentioned element substrate 3 via a liquid crystal display. Further, the mold member 103 serves as a mounting and positioning member for detachably fixing the entire liquid ejection head of the present embodiment to a liquid ejection device described later.

The inside of the element substrate 3 includes a mold member 10.
The communication path 105 for further supplying the liquid supplied through the liquid supply path 107 of the third substrate to the discharge port is provided on the element substrate 3.
Are provided to pass through. The communication passage 105 communicates with a liquid flow path that communicates with each discharge port, and has a role as a common liquid chamber.

Next, an example of a liquid discharge apparatus to which the above-described liquid discharge head can be mounted will be described.

In FIG. 11, reference numeral 200 denotes a carriage for detachably mounting the above-described liquid discharge head. In this example, four types of liquid discharge heads are mounted according to the type of ink color as a liquid, and each head has a yellow ink tank 201Y and a magenta ink tank 2
01M, a cyan ink tank 201C, and a black ink tank 201B are mounted on the carriage 200.

The carriage 200 is mounted on the guide shaft 20
The guide shaft 2 is supported by an endless belt 204 supported by the motor 2 and driven in a forward or reverse direction by a motor 203.
02 is reciprocable on arrow A in the direction of arrow A. Endless belt 204 is wound between pulleys 205 and 206.

The recording paper P as a recording medium is conveyed intermittently in the direction of arrow B perpendicular to the direction of arrow A. The recording paper P includes a pair of roller units 207 and 208 on the upstream side,
The sheet is nipped by a pair of roller units 209 and 210 on the downstream side, is applied with a constant tension, and is conveyed while ensuring flatness with respect to the head. The application of the driving force to each roller unit is performed by the driving unit 211,
The roller unit may be driven by using the above-described drive motor.

The carriage 200 stops at the home position as needed at the start of printing or during printing. At this position, a cap member 212 for capping the ejection opening surface of each head is provided.
Is connected to suction recovery means (not shown) for forcibly suctioning the discharge port on the discharge port surface to prevent clogging in the discharge port.

[0062]

As is apparent from the above description, according to the present invention, a structure is used in which ink is supplied to a single heater by a plurality of nozzles having different shapes, and nozzles having different shapes are formed at the boundaries of each heater group. By adopting an adjacent configuration,
Discharge at high frequency and stable discharge with little crosstalk can be performed. In addition, it is possible to reduce the loss due to the ejection power and the defect due to dust clogging.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a conventionally known ink jet head.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a diagram illustrating the flow of ink in FIG. 2;

FIG. 4 is a diagram showing the entire first embodiment of the present invention.

FIG. 5 is a conceptual diagram illustrating a first embodiment of the present invention.

FIG. 6 is a diagram illustrating driving of the heater of FIG. 5;

FIG. 7 is a diagram showing a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a third embodiment of the present invention.

FIG. 9 is a diagram illustrating driving of the heater of FIG. 8;

FIGS. 10A and 10B are diagrams showing a schematic configuration of a liquid discharge head of the present invention, wherein FIG. 10A is a perspective view showing an external appearance, and FIG. It is sectional drawing which follows the -A line.

FIG. 11 is a schematic perspective view showing an example of a liquid ejection apparatus to which the liquid ejection head of the present invention can be mounted.

[Explanation of symbols]

 1, 11, 12, 13, 14, 15, 16 Heater 2 Orifice (discharge port) 3 Substrate 4 Nozzle 5 Nozzle wall 6 Common liquid chamber 7 Supply port 8 Nozzle plate 11a, 11b, 12a, 12b Nozzle

Claims (10)

[Claims] At least one electrothermal converter provided to face a discharge port for discharging liquid droplets, and at least two liquid supply paths for supplying a liquid to the electrothermal converter. Wherein the at least two liquid supply paths, which are to supply liquid to the same electrothermal transducer, have different flow resistances in the respective liquid supply paths. head. 2. The liquid discharge head according to claim 1, wherein the liquid supply paths have different shapes. 3. The electrothermal converter comprises at least two groups, a first group comprising a first liquid supply passage connecting a first liquid chamber and the electrothermal converter, And a second liquid supply path connecting the second liquid chamber and the electrothermal transducer and having a larger flow resistance than the first liquid supply path. A second group includes the first liquid chamber and the second liquid supply path. A third liquid supply path that communicates with the electrothermal converter; a fourth liquid supply path that connects the second liquid chamber and the electrothermal converter and has a smaller flow resistance than the third liquid supply path. The liquid ejection head according to claim 1, further comprising a liquid supply path. 4. The discharge port is constituted by a plurality of discharge lines, and is arranged in a row, and the first liquid supply path of the first group of the electrothermal transducers and the first liquid supply path of the second group are 3 liquid supply passages are arranged on one side with respect to the row of discharge ports,
The liquid supply path of the first group and the fourth liquid supply path of the second group are arranged on the other side with respect to the row of the discharge ports. The liquid discharge head according to any one of Items 1 to 3. 5. The electrothermal converters belonging to the first group and the electrothermal converters belonging to the second group are alternately arranged along the rows of the discharge ports. The liquid ejection head according to claim 4, wherein 6. The liquid discharge head according to claim 5, wherein flow resistances of adjacent liquid supply paths are alternately different. 7. The liquid ejection head according to claim 3, wherein the first liquid chamber and the second liquid chamber communicate with each other. 8. A liquid discharge head that discharges the liquid from the discharge port to the outside by using a pressure of a bubble formed in the liquid by the electrothermal transducer, wherein the pressure in the bubble is outside. The liquid ejection head according to any one of claims 1 to 7, wherein the bubble and the outside air communicate with each other in the vicinity of the ejection port when the pressure is lower than the atmospheric pressure. 9. The liquid discharge head according to claim 1, wherein the liquid is ink. 10. A liquid discharge apparatus that discharges the liquid using the liquid discharge head according to claim 1. Description: