JP2983303B2 - Liquid jet recording head and liquid jet recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording apparatus for performing recording by using a liquid discharged from a discharge port and a liquid jet recording head for performing the above discharge, and more particularly to a liquid jet recording head for performing the discharge by utilizing thermal energy. The present invention relates to a liquid jet recording head for performing the above and a liquid jet recording apparatus using the head.

[0002]

2. Description of the Related Art In liquid jet recording in which a liquid is ejected by using thermal energy, for example, an electrothermal converter is used as an energy generating means for ejecting the liquid, and the thermal energy generated here acts on the liquid on its heat acting surface. To vaporize and generate air bubbles. The recording is performed by discharging the liquid from the discharge port by the pressure fluctuation of the liquid accompanying the generation of the bubble.

[0003] Recording by this method has the advantages that the ejection ports for ejecting the recording liquid can be arranged at a high density, so that a high resolution can be obtained in a recorded image and the recording head can be downsized. Have.

However, in order to arrange the discharge ports at a high density, it is necessary to make the liquid flow path thinner. In this case, after the inertance and the impedance of the liquid flow path are increased and the liquid is discharged, the time (refill time) from when the recording liquid is filled from the supply port to when a meniscus is formed near the discharge port of the liquid flow path becomes longer. This is an obstacle to performing high-speed recording.

On the other hand, the inertia and the impedance can be reduced by shortening the liquid flow path, and the refill time can be shortened. In addition, there has been a case where the volume is reduced and stable recording cannot be performed.

Japanese Patent Application Laid-Open No. 60-204352 discloses a method of supplying a recording liquid to a supply port side of an electrothermal converter in a liquid flow path so as to solve this problem and perform stable ejection even in a short liquid flow path. There is disclosed an ink jet recording head provided with a resistor for reducing outflow to the mouth side.

Japanese Patent Application Laid-Open No. 1-87356 discloses that in order to improve the ratio of the energy used by the air bubbles to be discharged,
There is disclosed an ink jet recording head having a structure in which a sectional area orthogonal to a flow of a liquid flow path in the vicinity of a heat generating portion is larger on a discharge port side. Furthermore, Japanese Patent Application Laid-Open No. 1-195050 discloses that the liquid flow path, which is a component of Japanese Patent Application Laid-Open No. Specific examples of what not to do are published.

[0008]

However, in the method described in Japanese Patent Application Laid-Open No. 60-204352, it is difficult to (1) provide a resistor in the liquid flow path as the density and the number of nozzles increase. (2) If the resistor is too far from the electrothermal converter, the effect of the resistor will be reduced, and if it is too close, bubbles generated will be directed between the resistor and the flow path wall. And the effect as a resistor is reduced by half. Therefore, it is difficult to optimally design the shape, size, position, etc. of the resistor, and even if it can be optimally designed, the effect cannot be said to be sufficient.

The method disclosed in Japanese Patent Application Laid-Open No. 1-87356 improves the energy efficiency, but has a limit to the formation of multiple nozzles. According to the invention described in this, since the cross-sectional area of the liquid flow path increases toward the discharge side, the wall separating the adjacent liquid flow paths is necessarily thinned. However, if the wall is too thin, the strength becomes insufficient, or the pressure of the bubbles is transmitted to the adjacent liquid flow path, which adversely affects the discharge, and is not suitable for high density and multi-nozzle.

Further, according to the above-mentioned Japanese Patent Application Laid-Open No. 1-195050, since the liquid flow path is not blocked by bubbles, the recording liquid can be sufficiently supplied.
Stable discharge can be performed. However, this publication only states that "the ceiling near the energy action portion of the thermal liquid jet recording head is higher than the other portions."

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a multi-nozzle liquid jet recording head capable of stably performing high-density high-speed recording and a liquid jet recording apparatus using the same. I do.

[0012]

According to the present invention, there is provided:
A plurality of discharge ports provided for discharging droplets by utilizing thermal energy, a plurality of liquid flow paths to which the liquids for forming the droplets are respectively communicated with the discharge ports, and the liquid A plurality of supply ports for supplying the liquid to each of the flow paths; and a plurality of electrothermal converters as means for generating thermal energy provided corresponding to each of the supply ports. Each of the heat converters is a liquid jet recording head having a heat acting surface as a surface on which the generated thermal energy acts on the liquid at the bottom surface of the liquid flow path, in the flow path arrangement direction of the liquid flow path. The width is
The maximum value between the center of the gas heat converter and the discharge port
And discharge from at least the portion of the maximum value.
Monotonous decrease in any direction to the mouth and the supply port
It is characterized by doing.

Also, a plurality of discharge ports provided for discharging liquid droplets by utilizing thermal energy, and a plurality of liquid streams respectively connected to the discharge ports and supplied with the liquid for forming the liquid droplets. Channels, a plurality of supply ports for supplying the liquid to each of the liquid flow paths, and a plurality of electrothermal converters as means for generating thermal energy provided corresponding to each of the discharge ports. Each of the electrothermal transducers has a liquid jet recording head having a heat acting surface as a surface on which the generated thermal energy acts on the liquid at a bottom surface of the liquid flow path. In the jet recording apparatus, the width of the liquid flow path in the flow path arrangement direction is
The maximum value between the center of the gas heat converter and the discharge port
And discharge from at least the portion of the maximum value.
Monotonous decrease in any direction to the mouth and the supply port
It is characterized by doing.

[0014]

According to the configuration described above [action], air bubbles generated by the heat of the electro-thermal transducer during the discharge of liquid droplets in the liquid flow path,
Maximum width between the center of the electrothermal transducer and the outlet
In this case, the impedance in the ejection direction can be reduced by this maximum width portion in the liquid flow path . Further, when the recording liquid is refilled, since the diverging pipe is formed from the supply port toward the ejection port side, the impedance at the time of refilling can be reduced, and this increases the impedance at the time of ejection.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, the principle of the present invention, which underflows in each of the embodiments described below, will be described.

The structure of the liquid flow path in the recording head is determined by considering all of the size and position of the electrothermal transducer, the generated thermal energy, the flow path resistance of the liquid flow path, and the size and shape of the discharge port. The amount and speed of droplets to be determined are determined according to the target values.
Alternatively, it may not be able to be set arbitrarily because of geometric restrictions. If there is no such restriction, the liquid flow path should be large and short because the smaller the flow path resistance (impedance, inertance) is, the higher the efficiency is. Therefore, the size and position of the electrothermal converter, the size of the discharge port, etc. Adjust
The amount and speed of the droplet can be adjusted to the target value. However, for example, in the case of a multi-nozzle (multiple discharge ports),
There are various restrictive factors such as the width of the liquid flow path being restricted by the presence of the partition wall between the adjacent liquid flow paths, and the need to consider that the partition wall is too thin and insufficient in strength. Exists.

The present invention utilizes the directionality and flow rate dependence of the fluid impedance. That is, as described above, it is desired that the impedance of the liquid flow path be as small as possible over the entire flow path. However, by making the impedance of the liquid flow path different between when ejecting a droplet and when supplying a recording liquid, the directionality and With flow rate dependency
As a result, the efficiency of ejection and refilling is improved.

In this description, the impedance of the liquid flow path is set to the discharge port side (front) and the supply port side (rear) from the electrothermal converter.
It is easy to understand if you think about it. At the time of discharging droplets, if the recording liquid easily moves forward and does not easily move backward, efficient discharge can be performed. That is, it is desirable that the impedance be smaller at the front than at the rear. On the other hand, when the recording liquid is supplied, the recording liquid that has retreated in the liquid flow path attempts to return to the original position. That is, the impedance needs to be reduced both in the front and the rear. That is, if the front impedance is always small, and the rear impedance is large when the recording liquid is ejected and small when the recording liquid is supplied, efficient ejection and refilling can be performed. In this way, the rear impedance is required to have conflicting characteristics in some cases.

The adjustment of the length and width of the liquid flow path is a method of effectively changing the impedance of the liquid flow path. The present invention has focused on width. Between the liquid flow path width and the impedance,
In general, there is a relationship that the impedance decreases as the width increases, and the impedance increases as the width decreases. From the above, it is desirable to increase the front width and decrease the rear width during droplet discharge,
When the recording liquid is supplied, the rear width is preferably large, and contradictory characteristics are required. However, this contradiction can be almost completely eliminated by taking into account the difference in the movement of the recording liquid between the time of ejection and the time of supply.

That is, the present inventors have paid attention to the difference in time required for ejection and supply. Since the discharge is performed in a shorter time than the supply, the flow velocity is high, and the supply is a slow flow. By devising the flow velocity difference and the structure of the liquid flow path, the impedance can be made directional and flow velocity dependent.

First, the rear of the liquid flow path will be described. According to the liquid flow path structure of the present invention, the recording liquid at the time of discharge is a tube (a narrowing tube) whose width decreases from the electrothermal converter toward the supply port.
It will flow fast, so it is difficult to flow. That is, compared with the case where the width is constant, the impedance is increased with respect to the flow in the direction opposite to the discharge direction, and the discharge can be performed efficiently. On the other hand, at the time of supply, the direction of the flow is reversed, and the flow slowly flows through a pipe (spreading pipe) having a larger width from the supply port to the electrothermal converter. Done in Next, the front of the liquid flow path will be described. In front, when discharging,
At the time of supply, the flow of the recording liquid is directed from the electrothermal converter to the ejection port side. Therefore, in order to improve the efficiency, a structure of a divergent pipe facing the discharge port may be used.

From the above, it can be said that the efficiency of the whole flow path is improved if the flow path has a divergent pipe structure from the supply port to the discharge port. However, the structure in front of the liquid flow path is
Because of the important role of controlling the ejection speed, the structure cannot be determined only by the factors that give priority to the efficiency of ejection or the like as described above. Further, in the structure of a simple expanding pipe as described above, there is a limit in increasing the density of the liquid flow path and in forming a multi-nozzle. Thus, the front structure of the present invention was born. In other words, the structure is such that the width of the liquid flow path decreases from the electrothermal transducer portion toward the discharge port in order to control the amount of the droplet and the discharge speed. At this time, it is desirable that the maximum width portion of the liquid flow path is further forward (discharge port side), but the effect of the present invention can be realized if it is closer to the discharge port than the electrothermal converter which acts as the center of action for generating the discharge pressure. it can. According to this structure, the efficiency of ejection and the like is improved, so that it is relatively easy to control the number of droplets to a desired amount and ejection speed, and it is possible to increase the density and the number of nozzles.

That is, according to the present invention, the liquid flow path structure which becomes a divergent pipe from the supply port side to the electrothermal converter section has a maximum liquid flow path width in front of the central section of the electrothermal converter section,
Since the portion having the maximum width is extremely small, the width can be maximized in consideration of the pitch of the liquid flow path. Thereby, the flow path impedance of the entire liquid flow path can be reduced. On the other hand, in the conventional liquid flow path, the maximum liquid flow path width is relatively long, so that the thickness of the partition wall can be reduced in consideration of the strength of the partition wall and the influence of the bubble pressure on the adjacent liquid flow path. However, this width was smaller than the pitch of the liquid flow path. Therefore, the multi-nozzle can be reduced in size according to the present invention. In the present invention, the length of the portion forming the maximum flow path width is determined from the characteristics of the material forming the partition wall of the liquid flow path, the rate of monotonously decreasing toward the discharge port and the supply port, and the like. When the length is 0), the widest width can be realized. In addition, since the distance between the electrothermal transducer and the wall of the liquid flow path can be increased, the bubbles can grow without being restrained by the walls, and the efficiency of converting the energy of the bubbles into the discharge energy can be improved.

Example 1 and Comparative Example As shown in FIG. 1, partition walls 7 are formed at regular intervals on a substrate 4, an electrothermal converter 5 is provided between them, and a top plate 6 is covered thereon to eject liquid. A recording head was obtained. The space surrounded by the partition, the substrate and the top plate becomes the liquid flow path 1, and the liquid to be discharged is supplied from the supply port 3 and discharged from the discharge port 2.

In the vicinity of the center of the electrothermal converter 5, the width of the partition wall is set to almost zero, and the width of the liquid flow path 1 is maximized (in the figure, a certain width is taken for explanation).

The dimensions of each part are as follows: discharge port area 40 × 30 μm
^2. Liquid channel length 500 μm, liquid channel height 40 μm, size of electrothermal transducer 32 × 150 μm ² , liquid channel pitch 10
It was 5.8 μm. Liquid flow path width is maximum 95 .mu.m (substantially central portion of the electrothermal transducers), minimum 30 [mu] m (supply port portion)
And

FIG. 2 is a plan view showing a portion of the liquid flow path 1 of the present embodiment.

A conventional liquid jet recording head is used as a comparative example,
FIG. 13 shows a diagram corresponding to FIG. In the comparative example, the liquid flow path 1 is not narrowed in the direction of the supply port 3.

In the comparative example, the liquid flow path width was set to a maximum of 70
The dimensions of each part are the same as those of the first embodiment, except that μm (main part of the liquid flow path) and minimum 35 μm (discharge port part).

The operation of this embodiment will be described in comparison with a comparative example.

When an electric pulse is applied to the electrothermal converter 5,
Bubbles 8 are generated and grow as shown in FIGS. In the present embodiment, since the width of the liquid flow path 1 has the maximum value at the substantially central portion of the electrothermal converter, the bubbles 8 are less affected by the partition walls and grow freely in an elliptical shape. On the other hand, the maximum width of the flow path of the comparative example is structurally narrower than that of the present embodiment, so that the presence of the wall influences the growth of the bubble 8, and the bubble 8 is considerably longer than the electrothermal converter and becomes a gourd shape shown in FIG. Become. For this reason, the efficiency of utilizing the energy of bubbles is better in this embodiment.

In the present embodiment, when the recording liquid is supplied, the recording liquid spreads from the supply port 3 and flows through the tubular liquid flow path 1 relatively slowly, so that the impedance at the time of supply is smaller than that at the time of ejection. The comparative example does not have this effect. In the structure of the comparative example, since the difference in impedance between discharge and supply is small, it is difficult to satisfy the above-described characteristics required for the liquid flow path during discharge and during supply. Therefore, the impedance is determined by the balance between the two. On the other hand, according to the present embodiment, the characteristics required for both can be almost satisfied.

Second Embodiment A liquid jet recording head according to a second embodiment shown in FIG.
Length 200 μm, size of electrothermal transducer 5 45 × 35
The same as Example 1 except that μm ² was used. In this example, the effect of the wide liquid flow path width, which is a feature of the present invention, is utilized to the utmost, and the maximum liquid flow path width and the electrothermal transducer 5 are brought closer to the discharge port 2 side. Widen the liquid flow path 1
Was shortened.

The reason why the electrothermal transducer 5 can be brought close to the discharge port 2 is that bubbles can grow freely and do not extend in the flow direction of the recording liquid as in the comparative example. That is, in the comparative example shown in FIG. 13, when the electrothermal transducer 5 is too close to the discharge port 2, the air bubbles 8 communicate with the outside air and the liquid flow path 1
In some cases, air may get inside and cause discharge failure, but in this embodiment, this concern has been eliminated. Further, since the electrothermal converter 5 is close to the discharge port 2, the discharge can be performed by the small electrothermal converter 5, thereby achieving high efficiency and energy saving. Further, since the flow path length can be shortened, there is also an effect of reducing the impedance of the entire liquid flow path 1, and the efficiency is considerably improved as compared with the conventional case.

Example 3 As shown in FIG. 4, electrothermal transducers 5 were formed at regular intervals on a substrate 4 (FIG. 4 is omitted for the sake of clarity). The electrothermal transducer 5 of the top plate 6
The liquid flow path 1 was formed by providing a groove at a position corresponding to. The liquid ejecting recording head was obtained by combining the top plate 6 and the substrate 4. Each liquid flow path 1 is separated by a partition 7. The liquid to be discharged is supplied from the supply port 3 and discharged from the discharge port 2.

Near the center of the electrothermal converter 5, the width of the partition wall 7 is set to almost zero (a certain width is taken for illustration in the figure) to maximize the liquid flow path width, The path height was maximized, and the cross-sectional area of the liquid flow path 1 was maximized in this portion.

The dimensions of each part are as follows: discharge port area 35 × 35 μm
^2. Same as Example 1 except that the maximum height of the liquid flow path was 60 μm.

FIG. 5A is a plan view showing a portion of the liquid flow path of the present embodiment, FIG. 5B is a sectional view taken along the line aa 'of FIG. 5, and FIG. It is b 'sectional drawing.

The operation and effect of this embodiment are the same as those of the first embodiment.

[0041]

[Table 1]

Table 1 shows the characteristics of the liquid jet recording heads of Examples 1, 2, and 3 and Comparative Example. As can be seen from the table, the liquid jet recording heads of the examples have excellent characteristics.

Fourth Embodiment FIGS. 6 and 7 show views similar to FIGS. 1 and 2, respectively, showing a modification of the first embodiment. That is, the liquid flow path 1
In this embodiment, the maximum width portion is arranged further from the central portion of the electrothermal converter 5 shown in Embodiment 1 to the discharge port side. Thereby, the growth of the bubble 8 is promoted to the ejection port 2 side, and the ejection efficiency can be further improved.

In each of the embodiments described below, the maximum width position is similarly located closer to the discharge port.

Further, in the structure shown in this embodiment, similarly to the embodiment shown in FIG. 5, the height of the liquid channel at the position of the maximum width may be maximized.

Further, as shown by broken lines a, b and c in FIG. 7, the structure of the liquid flow path 1 may be a structure shown by any of these broken lines or a combination thereof. That is, the effect of the present invention is a structure in which the maximum width portion of the liquid flow path is constituted by a point or an extremely short line, and the width decreases at least toward the front and the rear thereof. Obtained by being greater than that at the rear. This is a principle common to the embodiments of the present invention.

Fifth Embodiment FIG. 8 is a view similar to FIG. 3, showing a modification of the second embodiment. In the present embodiment, the maximum width position of the liquid flow path 1 is determined according to the second embodiment.
3 shows a structure shifted to the ejection port 2 side as compared with the case of FIG.

In the configuration shown in FIGS. 3 and 8, the width of the electrothermal transducer 5 in the ink flow direction is larger than the width of the embodiment shown in FIGS. Converter 5
Is longer than the length in the ink flow direction. This configuration ensures that the bubbles grow in the width direction, and the electrothermal converter 5
This is preferable because it is possible to discharge the ink located on the discharge port side more reliably and quickly, and to further improve the refill characteristics.

In addition, since the width of the discharge port in the embodiment shown in FIGS. 3 and 8 is smaller than the width of the electrothermal transducer 5, the rapid and quick ink discharge force in the flow path is more concentrated. It enables good recording.

Further, in the configuration shown in FIG. 8, the end of the electrothermal transducer 5 on the discharge port 2 side is not a region where the flow path width monotonously decreases, but a portion having substantially the same flow path width (or a monotonous flow path width). The area may increase). The configuration of FIG. 8 has the above-described width configuration as compared with the embodiments of FIGS.

According to these, the grown bubbles are likely to grow toward both side walls on the upstream side having a width smaller than the maximum width, so that the ink in the downstream area after the electrothermal converter is rapidly discharged to the discharge port side. Can be directed to Moreover, in this example, the growth of bubbles can be made relatively small toward the upstream side, so that the refill effect is also excellent.

Embodiment 6 FIGS. 9, 9A and 9B are FIGS. 4 and 5 respectively.
14A and 14B are diagrams similar to FIGS. 14A and 14B and show a modification of the third embodiment.

In FIGS. 9, 10 (a) and 10 (b), the width of the partition wall 7 is made substantially zero on the surface of the substrate 4 on the side of the discharge port 2 from the center of the electrothermal transducer 5, and Maximize width. Further, the height of the liquid flow path was further maximized on the side of the discharge port 2 than the maximum part of the liquid flow path width, and the maximum section of the liquid flow path was provided on the side of the discharge port 2 from the center of the electrothermal converter 5.

The dimensions of each part are as follows.
5 μm ² , liquid flow path maximum width 95 μm, liquid flow path maximum height 60
It is the same as the first embodiment except that the width of the liquid channel ceiling at the maximum height of the liquid channel is 45 μm.

FIG. 11 shows the above-described liquid jet recording head, which is of a replaceable type in which an ink tank is integrated.

The recording head 10 shown in the figure has a top plate having a concave portion (groove) for forming a liquid flow path and a common liquid chamber as described above, an electrothermal transducer for generating discharge energy, and An Al wiring or the like for supplying an electric signal thereto is formed by joining a substrate formed on a Si substrate by a film forming technique.

In the figure, reference numeral 600 denotes a sub ink tank disposed adjacent to the recording head main body 10, and the sub ink tank 600 and the main body are provided with lids 300 and 8 respectively.
Supported by 00. Further, reference numeral 1000 denotes a cartridge main body, and 1100 denotes a lid member of the cartridge main body. An ink tank is built in the cartridge body, and supplies ink to the sub ink tank 600 as appropriate.
The above recording head body 10 and cartridge body 1000
These make the recording head cartridge 80
Can be obtained.

The recording head of the present invention can be obtained in the form of a cartridge 80 as shown in FIG. 11, and can be used to constitute a liquid jet recording apparatus as shown in FIG.

In FIG. 12, reference numeral 80 denotes the cartridge shown in FIG. 11. The cartridge 80 is fixed on the carriage 51 by a pressing member 81.
These can be reciprocated in the longitudinal direction along the shaft 21. The positioning with respect to the carriage 51 can be performed by, for example, a hole provided in the lid 300 and a dowel provided on the carriage 15 side. Further, the electrical connection is made to the connection pads provided on the wiring board by the carriage 51.
What is necessary is just to couple the upper connector.

The ink ejected by the recording head reaches the recording medium 18 whose recording surface is regulated by the platen 19 at a minute interval from the recording head, and forms an image on the recording medium 18.

The recording head is supplied with an ejection signal corresponding to image data from an appropriate data supply source via a cable 16 and a terminal connected thereto. Cartridge 80
One or more (two in the figure) can be provided according to the ink color or the like to be used.

In FIG. 12, 17 is a carriage motor for scanning the carriage 51 along the shaft 21, and 22 is a driving force of the motor 17 for the carriage 51.
Wire to be transmitted to Reference numeral 20 denotes a feed motor which is coupled to the platen roller 19 to convey the recording medium 18.

Although the discharge port of this embodiment is shown as a monotonically reduced end, the discharge port may be a discharge port having a smaller area than the monotonically reduced partial end. The discharge section may have a thickness (length in the flow direction).

(Others) The present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the electric connection with the apparatus main body and the ink from the apparatus main body can be provided by being mounted on the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

It is preferable to add recovery means for the recording head, preliminary auxiliary means, and the like provided as a configuration of the recording apparatus in the present invention since the effects of the present invention can be further stabilized. . If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof, Performing a preliminary ejection mode in which ejection is performed separately from printing is also effective for performing stable printing.

The type and number of recording heads to be mounted are, for example, different from those provided with only one ink corresponding to a single color ink and those corresponding to a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, but may be any of integrally forming the printing head or a combination of a plurality of printing heads. The present invention is also extremely effective for an apparatus provided with at least one of full colors by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature, or an ink jet system In general, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Anything can be used. In addition, the temperature rise due to thermal energy can be positively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or ink that solidifies in a standing state to prevent evaporation of the ink can be used. In any case, the ink is liquefied by the application of the thermal energy according to the recording signal, and the ink is liquefied, and the liquid ink is discharged. The present invention is also applicable to a case where an ink that liquefies for the first time by energy is used. In such a case, the ink is disclosed in JP-A-54-56847 or JP-A-60
As described in JP-A-71260, a configuration may be adopted in which a liquid or solid substance is held in a concave portion or through hole of a porous sheet and opposed to an electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not limited to those used as image output terminals of information processing equipment such as computers, copying apparatuses combined with readers and the like, and facsimile apparatuses having a transmission / reception function. It may take a form.

[0073]

According to apparent the present invention from the description above, according to the present invention, air bubbles generated by the heat of the electro-thermal transducer during the discharge of liquid droplets in the liquid flow path, the central portion of the electrothermal transducers
Grows at the maximum width between the discharge port and
The impedance in the ejection direction can be reduced by this maximum width portion in the liquid flow path . Further, when the recording liquid is refilled, since the diverging pipe is formed from the supply port toward the ejection port side, the impedance at the time of refilling can be reduced, and this increases the impedance at the time of ejection.

As a result, it is possible to obtain a liquid jet recording head and a device suitable for increasing the density and increasing the number of nozzles, while improving the efficiency of using the energy of bubbles for discharging the recording liquid. Furthermore, if the width of the liquid flow path is maximized, the efficiency will be further increased, and much more energy saving can be realized as compared with the conventional case.

Further, it is possible to obtain a liquid jet recording head and an apparatus thereof which have a discharge speed equal to or higher than the conventional one.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a liquid jet recording head according to a first embodiment.

FIG. 2 is a plan view of the liquid flow path portion.

FIG. 3 is a plan view of a liquid flow path according to a second embodiment.

FIG. 4 is a partial perspective view of a liquid jet recording head according to a third embodiment.

FIGS. 5A, 5B, and 5C are a plan view and a cross-sectional view, respectively, of the liquid flow path portion.

FIG. 6 is a partial perspective view of a liquid jet recording head according to a fourth embodiment.

FIG. 7 is a plan view of the liquid flow path portion.

FIG. 8 is a plan view of a liquid channel portion according to a fifth embodiment.

FIG. 9 is a partial perspective view of a liquid jet recording head according to a sixth embodiment.

FIGS. 10A and 10B are a plan view and a cross-sectional view, respectively, of the liquid flow path portion.

FIG. 11 is an external perspective view of a head cartridge configured using the liquid jet recording head according to the embodiment of the present invention.

FIG. 12 is an external perspective view of a liquid jet recording head that can use the cartridge.

FIG. 13 is a plan view of a liquid flow path portion of a conventional liquid jet recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid flow path 2 Discharge port 3 Supply port 4 Substrate 5 Electrothermal converter 6 Top plate 7 Partition wall 8 Bubble

Claims (8)

(57) [Claims] 1. A plurality of discharge ports provided for discharging liquid droplets by utilizing thermal energy, and a plurality of liquid flows respectively connected to the discharge ports and supplied with a liquid for forming the liquid droplets. Channel, a plurality of supply ports for supplying the liquid to each of the liquid flow paths, and a plurality of electrothermal converters as means for generating thermal energy provided corresponding to each of the supply ports. Wherein each of the electrothermal transducers has a heat-acting surface on the bottom surface of the liquid flow path as a surface on which the generated thermal energy acts on the liquid; The width in the channel array direction is
When the maximum value is taken from the center of the body to the outlet
In addition, at least the discharge port and the portion from the maximum value
Monotonously decreasing in any direction up to the supply port
Liquid jet recording head, characterized in that. 2. The liquid passage according to claim 1, wherein said liquid passage has a width in a direction in which said liquid passage is arranged.
The rate of decrease in the discharge port side is large.
The liquid jet recording head according to claim 1. 3. The height of the liquid flow path in the flow path arrangement direction.
Is a distance from the center of the electrothermal transducer to the discharge port.
At the maximum value, and at least the maximum value part
To the discharge port and the supply port in any direction
3 is also monotonically decreasing.
3. The liquid jet recording head according to item 1. 4. cause film boiling in the liquid by said thermal energy, claims 1, wherein the discharging droplets on the basis of the generation of bubbles due to the film boiling 3 Neu
A liquid jet recording head according to any of the preceding claims. 5. A plurality of discharge ports provided for discharging liquid droplets by utilizing thermal energy, and a plurality of liquid streams each of which communicates with said discharge port and is supplied with a liquid for forming said liquid droplets. Channels, a plurality of supply ports for supplying the liquid to each of the liquid flow paths, and a plurality of electrothermal converters as means for generating thermal energy provided corresponding to each of the discharge ports. Each of the electrothermal transducers has a liquid jet recording head having a heat acting surface as a surface on which the generated thermal energy acts on the liquid at a bottom surface of the liquid flow path. In the jet recording apparatus, the width of the liquid flow path in the flow path arrangement direction may be the electrothermal conversion.
When the maximum value is taken from the center of the body to the outlet
In addition, at least the discharge port and the portion from the maximum value
Monotonously decreasing in any direction up to the supply port
Liquid jet recording apparatus characterized by. 6. The width of the liquid flow path in the flow path arrangement direction.
The rate of decrease in the discharge port side is large.
The liquid jet recording apparatus according to claim 5, wherein 7. The height of the liquid flow path in the flow path arrangement direction.
Is a distance from the center of the electrothermal transducer to the discharge port.
At the maximum value, and at least the maximum value part
To the discharge port and the supply port in any direction
7. The device according to claim 5, wherein said value also monotonically decreases.
3. The liquid jet recording apparatus according to item 1. 8. cause film boiling in the liquid by said thermal energy, 5 to claim, characterized in that for discharging droplets on the basis of the generation of bubbles due to the film boiling 7 Neu
A liquid jet recording apparatus according to any of the preceding claims.