JP2000203024A - Ink jet recording head, ink jet recording head cartridge and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve discharge characteristics such as a discharge speed and a refill frequency in an ink jet recording head having a plurality of electrothermal conversion elements in a flow path. SOLUTION: Two heaters (electrothermal conversion elements) SH1 and SH2 are provided in an ink flow path 12 having an ejection port 11 opened.
Is provided. The shape of one heater SH1 is rectangular, and the shape of the other heater SH2 is a trapezoid in which the width of the end on the discharge port 11 side is smaller than the width of the end on the liquid chamber 13 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head, an ink jet recording head cartridge and an ink jet recording apparatus used for a printer or a video printer as an output terminal of a copying machine, a facsimile, a word processor, a host computer or the like.
In particular, the present invention relates to an ink jet recording head having an electrothermal conversion element that generates thermal energy used as energy for ejecting ink. Here, the recording includes the ink application (printing) of all the ink supports to which the ink is applied, such as cloth, thread, paper, and sheet material, and includes not only meaningful images such as characters but also images. , Pattern images and the like. The recording device includes all of various information processing devices or a printer as an output device thereof, and the present invention can be used for them.

[0002]

2. Description of the Related Art An ink jet recording apparatus which performs recording on a recording medium by discharging ink is manufactured in many products from the viewpoints of easiness in miniaturization of the apparatus and low noise. In recent years, the handling of image images has increased, and the demand for high-quality color printing, particularly for halftone (halftone) images, has increased.

Conventionally, as a method of expressing halftone in an ink jet recording apparatus, a method of expressing the number of ejected ink droplets per predetermined area on a recording medium (pseudo halftone expression in binary), a discharge amount There is a method of arranging a plurality of recording heads having different recording heads or a plurality of recording heads for ejecting inks having different densities, and selecting and driving the recording heads according to the halftone to express the halftone. However, these methods may not be able to significantly improve the resolution, or may require a plurality of recording heads, so that the size of the recording apparatus may be increased. For this reason, there is a demand for an ink jet recording apparatus which changes the ejection amount in a single recording head in a plurality of stages, saves space in the recording apparatus at low cost, and has a high resolution.

In order to achieve this, a multi-heater ink jet recording head having a plurality of heaters having different areas arranged in one ink flow path is used, and each of the heaters is independently controlled and driven to discharge ink. A gradation recording method for realizing high-quality recording by changing the size of an ink droplet is disclosed, for example, in Japanese Patent Publication No. 62-48585.

[0005]

However, in order to realize the above-described multi-heater ink jet recording head, there are several problems as described below.

First, not only the ink discharge amount is made variable, but also the ink discharge speed is improved to perform high-quality printing, and the discharge reliability immediately after the discharge when the non-discharge time is long, etc. There is a demand for improvement in ink jetting and an improvement in landing accuracy of ink droplets. In particular, when an ink jet recording head having a multi-heater in one ink flow path is used, since a small ink droplet may be ejected from a large ejection port, it is difficult to increase the ejection speed suitable for small ink. There was a case.

Further, in order to enable high-speed recording, it is necessary to increase the refill (refill) frequency of the ink in the ink flow path. In particular, it is necessary to increase the refill frequency of a large ink droplet having a large ejection amount.

As another problem, there is a problem of compatibility with a general single-heater ink jet recording head having one heater in one ink flow path.
Many ink jet recording heads are removably mounted on the ink jet recording device in the form of a cartridge integrated with the ink tank that stores the ink, and are distributed as consumables that can be replaced with a new cartridge when the ink in the ink tank runs out. are doing. On the other hand, an ink jet recording apparatus using a single heater ink jet recording head is not configured to control the driving of a multi-heater ink jet recording head. It is also conceivable that an inkjet recording head is mounted. Therefore, in order to prevent confusion in the market, it is important to make the multi-heater ink jet recording head compatible with the single heater ink jet recording head.

In view of the above, according to the present invention, in a case where a plurality of electrothermal conversion elements are provided for one ink flow path in order to enable gradation recording, the discharge characteristics represented by the discharge speed and discharge amount of ink droplets are provided. It is an object of the present invention to provide an ink jet recording head or the like which further improves the recording quality. The present invention also provides
It is a second object of the present invention to provide an ink jet recording head or the like capable of improving a refill frequency to an ink flow path and performing high-speed recording. A third object of the present invention is to provide an ink jet recording head or the like which is compatible with an ink jet recording head provided with one electrothermal conversion element for one ink flow path.

[0010]

In order to achieve the above object, an ink jet recording head according to the present invention is provided with a plurality of electrothermal transducers which can be driven independently of each other in a flow path to which a liquid is supplied. In the ink jet recording head that foams the liquid in the flow path by driving the electrothermal conversion element and discharges the liquid from the discharge port opened in the flow path, at least one of the plurality of electrothermal conversion elements is The width of the end on the discharge port side is different from the width of the end on the side opposite to the discharge port in a trapezoidal shape.

In the ink jet recording head of the present invention configured as described above, when the electrothermal transducer provided in the flow path is driven, the liquid on the electrothermal transducer is heated and bubbles are generated. Then, droplets are ejected from the ejection ports by the action force based on the growth of the bubbles. The bubbles then defoam, at which time the liquid is refilled in the flow path.

Here, the inventors of the present invention have proposed an electric heat conversion element having a trapezoidal shape in which the width of the end on the discharge port side and the width of the end on the side opposite to the discharge port are different. It has been found that the ejection speed and the refill frequency can be improved without changing the area and position of the heat conversion element. For example, by making the width of the end on the discharge port side larger than the width of the end on the side opposite to the discharge port, the discharge speed is improved, and the width of the end on the discharge port side is changed to the end on the side opposite to the discharge port. By making the width smaller than the width of the portion, the refill frequency is improved. Therefore, by appropriately arranging such trapezoidal electrothermal conversion elements in a multi-heater ink jet recording head having a plurality of electrothermal conversion elements for one flow path, the discharge amount can be changed by changing the discharge amount. An ink jet recording head is provided which has an improved ejection speed or an improved refill frequency while enabling tone expression.

Moreover, the ink jet recording head of the present invention improves the ejection speed and the refill frequency without changing the area and position of the electrothermal transducer even when all electrothermal transducers in the flow path are driven simultaneously. It is possible. Therefore, the ink jet recording head of the present invention,
Even if it is installed in an inkjet recording device that uses a single heater inkjet recording head that has one electrothermal conversion element for one flow path, the ejection characteristics should be designed to be the same as that of a single heater inkjet recording head. Is easy.

An ink jet recording head cartridge of the present invention comprises the above ink jet recording head of the present invention,
And a tank for storing a liquid to be supplied to the ink jet recording head.

An ink jet recording apparatus of the present invention includes the above-described ink jet recording head of the present invention or a carriage on which the above-described ink jet recording head cartridge of the present invention is removably mounted, and further drives the ink jet recording head. And a recording signal supply means for supplying the recording signal to the inkjet recording head, and recording is performed by discharging liquid from the ejection port of the inkjet recording head based on the recording signal.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments. Further, in the following embodiments, ink will be described as an example of a liquid used for ejection, but is not limited thereto.
Any liquid may be used as long as the liquid can be ejected using the present invention.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of an ink flow path portion of the inkjet recording head according to the embodiment.

In the ink jet recording head of this embodiment, a plurality of ink flow paths 1 each having an opening 11
2 are arranged in parallel at a density of 360 dpi, and the end of each ink flow path 12 opposite to the ejection port is
2 is a common liquid chamber 13 for supplying ink. In each ink flow path 12, two heaters (electrothermal conversion elements) SH1 and SH2 are respectively provided.
Are arranged side by side in the width direction.

The planar shape of the heater SH 1 is a rectangle whose long side extends along the longitudinal direction of the ink flow path 12. The planar shape of the other heater SH2 is a trapezoid whose width gradually decreases from the liquid chamber 13 side toward the discharge port 11 side.
Further, the distance from the discharge port 11 to each of the heaters SH1 and SH2 is equal, and the length L of each of the heaters SH1 and SH2 is also equal.

In this embodiment, the rectangular heater SH1
Has a width W ₁ of 17 μm and a trapezoidal heater SH 2 has a discharge port 11.
The width W ₂₁ on the side was 14 μm, the width W ₂₂ on the liquid chamber side was 20 μm, and the length L of each of the heaters SH1 and SH2 was 130 μm.
Therefore, the areas of the heaters SH1 and SH2 are equal. The width of each ink channel 12 was 58 μm and the height was 40 μm.

In the ink jet recording head configured as described above, the ink supplied from an ink tank (not shown) is temporarily held in a liquid chamber 13 and further enters each ink flow path 12 by a capillary phenomenon and discharges. A meniscus is formed at the outlet 11 to keep the ink flow path 12 filled. In this state, a pulse voltage is applied to the heaters SH1 and SH2 to apply thermal energy to the ink, thereby causing a state change accompanied by a rapid change in volume of the ink. Is discharged. Specifically, when a voltage is applied to the heaters SH1 and SH3, the ink on the heaters SH1 and SH2 is heated to generate bubbles, and the ink is pushed out from the ejection ports by the pressure generated by the growth of the bubbles. Then, the ink is supplied (refilled) from the liquid chamber 13 to the ink flow channel 12 due to the contraction (defoaming) of the bubble, and the ink flow channel 12 is filled with the ink while the meniscus is formed again at the discharge port 11.

Each of the heaters SH1 and SH2 can be driven independently, and one of the heaters SH1 and SH2 can be driven independently.
The discharge characteristics are different between when only the heater SH2 is driven and when only the other heater SH2 is driven. Table 1 shows the discharge speed, discharge amount, and refill frequency, which are some of the indexes of the discharge characteristics.

[0023]

[Table 1]

As can be seen from Table 1, both heaters SH
Since the areas SH1 and SH2 have the same area, the discharge amounts are the same. However, different results were obtained for the heaters SH1 and SH2 with respect to the discharge speed and the refill frequency.

Generally, a heater generates more heat as the current density increases. Therefore, as shown in FIG. 2A, it is presumed that bubbles 15 are generated from the narrow side first in the trapezoidal heater SH2. However, bubble 1
5 is a very short time, and since the heater SH2 of the present embodiment is not a trapezoid in which the minimum width and the maximum width are greatly different, as shown in FIG. Next, it is considered that the bubble 15 grows while having anisotropy. In the process of defoaming the bubbles 15, the bubbles 15 are defoamed from narrower to wider.

On the other hand, as shown in FIG.
Since the width of the rectangular heater SH1 is constant, the bubbles 16 uniformly grow on the heater SH1 and disappear.

At the last stage in FIG. 2, the bubbles 15 and 16 disappear. At that time, the meniscus once retreats and reaches the discharge port 11 again by capillary action. The refill frequency is the reciprocal of the time required for the meniscus to reach the discharge port 11 again, and the refill frequency is generally inversely proportional to the amount of meniscus retreat. As shown in FIG. 2A, in the case of the trapezoidal heater SH2, the defoaming position of the bubble 15 shifts to the side where the width of the heater SH2 is widened, that is, the side away from the discharge port 11, so that the defoaming point is reduced. It is considered that the inertia of the ink on the ejection port side became larger, the amount of meniscus retreat was smaller than that of the rectangular heater SH1 having the same distance from the ejection port 11, and as a result, the refill frequency was increased.

As described in the present embodiment, the two areas having substantially the same area are used.
In a multi-heater ink jet recording head using two heaters SH1 and SH2, each heater SH
1 and SH2 are driven to discharge small ink droplets, and both heaters SH1 and SH2 are simultaneously driven to discharge large ink droplets. The gradation is obtained by combining these small ink droplets and large ink droplets. It is common to make an expression. One issue with multi-heater ink jet recording heads is how to increase the refill frequency of large ink droplets with a large ejection volume. For this reason, the position of the heater that is not used when ejecting small ink droplets is shifted to the liquid chamber side. The arranged configuration is also proposed by the present inventors.

On the other hand, in the present embodiment, the rectangular heater SH1 is driven to discharge ordinary small ink droplets, and the heaters SH1 and SH2 are simultaneously driven to discharge large ink droplets. Thereby, the heater SH from the discharge port 11
The refill frequency at the time of discharging a large ink droplet can be improved without shifting the positions of 1, SH2.

Here, as shown in FIG. 3, an ink jet recording head in which two rectangular heaters SH1 'and SH2' are arranged in parallel with the ink flow path 12 'is manufactured, and a large ink droplet is ejected. The refill frequency was compared with the ink jet recording head shown in FIG. 3, the shape and size of each of the heaters SH1 'and SH2' are equal to those of the heater SH1 shown in FIG. That is,
The widths W ₁ and W ₂ are both 17 μm, and the length is 130 μm
And As a result, the refill frequency of the inkjet recording head shown in FIG. 3 was 6.0 kHz, whereas the refill frequency of the inkjet recording head shown in FIG. 1 was 8.5 kHz. in this way,
By making one heater SH2 trapezoidal, the refill frequency is improved, and high-speed recording becomes possible.

A multi-heater ink jet recording head is compatible with a single heater ink jet recording head having one heater for one ink flow path, and uses only a single heater ink jet recording head. May be used for recording devices.

In this case, all heaters in the same ink flow path are simultaneously driven and only large ink droplets are ejected. However, if all heaters are rectangular, the ejection speed, ejection amount, etc. Even if an attempt is made to design the discharge characteristics of the ink jet recording head to be equal to that of a single-heater ink jet recording head, the length of the ink flow path from the discharge port to the liquid chamber cannot be changed significantly with respect to the single-heater ink jet recording head. . Further, it has been confirmed that it is effective to increase the length of the ink flow path in order to improve the refill characteristics.

Therefore, in the conventional multi-heater ink jet recording head, there is a limitation in changing the position and size of the heater, and it may be difficult to make the ink jet recording head compatible with the single heater ink jet recording head. . On the other hand, as shown in the present embodiment, the trapezoidal heater S
By providing H2, it is possible to obtain the same effect in a sense that the position of the heater is shifted, and to make the ejection characteristic equal to that of the single-heater inkjet recording head without changing the position of the heater so much. Becomes possible. That is, it is easy to make the ejection characteristics equal to those of a single-heater inkjet recording head.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of an ink flow path portion of the inkjet recording head according to the embodiment.

In this embodiment, two heaters SH which can be driven individually for one ink flow path 22 are also provided.
3 and SH4. In the present embodiment, each of the heaters SH3 and SH4 has a trapezoidal shape in plan view. The heaters SH3 and SH4 are arranged in opposite directions. One heater SH3 has a width decreasing from the discharge port 21 side to the liquid chamber 23 side, and the other heater SH3 has a smaller width.
H4 increases in width from the discharge port 21 side to the liquid chamber 23 side.

Each of the heaters SH3, SH4
To the heaters SH3, SH4
Is the width W _{31 of} one heater SH3 on the discharge port 21 side.
= Width W _{42 of the} other heater SH4 on the liquid chamber side = 20 μm,
The width W _{32 of} one heater SH3 on the liquid chamber 23 side = the width W _{41 of the} other heater SH4 on the discharge port 21 side = 14 μm. The lengths of the heaters SH3 and SH4 and the dimensions of the ink flow paths 22 were the same as those in the first embodiment.

Table 2 shows the discharge characteristics of the above-described ink jet recording head when the heaters SH3 and SH4 are individually driven and when the heaters are simultaneously driven.

[0038]

[Table 2]

As can be seen from Table 2, the discharge speed is higher when the heater SH3 is driven. As described in the first embodiment, the trapezoidal heater SH3
Is considered that the ink foams from the narrow side. Therefore, in the case of the present embodiment, it is considered that when a pulse voltage is applied to the heater SH3, foaming starts from the liquid chamber 23 side, and the bubbles gradually grow to the discharge port 21 side. Therefore, when the heater SH3 is driven, when foaming starts on the ejection port 21 side, a flow of ink is generated in the heater SH3 toward the ejection port 21, and bubbles are grown in such a manner that the flow is accelerated. It is considered that the discharge speed increases.

The refill frequency is higher when the heater SH4 is driven. This is the first
As described in the embodiment, it is considered that the defoaming position shifts to the discharge port 21 side in the heater SH3, and the defoaming position shifts to the liquid chamber 23 side in the heater SH4. However, when both heaters SH3 and SH4 are driven simultaneously, the effect of the heater SH4 is
3, and the refill frequency is lower than when only the heater SH4 is driven.

As described above, in the configuration of this embodiment, although the refill frequency when a large ink droplet is ejected is slightly lower than that of the first embodiment, the ejection of the small ink droplet by driving only the heater SH1 is performed. Speed is greatly improved.
Thereby, the ejection reliability of the small ink droplet is improved.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of an ink flow path portion of the inkjet recording head according to the embodiment.

In the above-described first and second embodiments, two heaters are arranged at the same position from the discharge port. However, in this embodiment, two heaters S
H5 and SH6 are arranged at positions different from each other from the discharge port 31, and one heater SH5 is located closer to the discharge port 31 than the other heater SH6. Each heater SH5, S
As in the second embodiment, the shape of H6 is trapezoidal in plan view, and one heater SH5 becomes narrower from the discharge port 31 side toward the liquid chamber 33 side, and the other heater SH6 becomes narrower.
Are arranged such that the width increases from the discharge port 31 side toward the liquid chamber 33 side.

In order to perform high-definition printing, it is preferable to reduce the arrangement pitch of the ink flow paths 32. Therefore, the width of the ink flow paths 32 should be as small as possible. But,
In the structure where two heaters SH5 and SH6 are arranged side by side,
The width of heaters SH5 and SH6 is limited. Therefore, as shown in FIG. 5, the two heaters SH5 and SH
6, the discharge ports 3 of the heaters SH5 and SH6 can be arranged without increasing the width of the ink flow path 32.
The ratio between the width on the one side and the width on the liquid chamber 33 side can be increased, and the discharge speed can be further increased. Also, when discharging small ink droplets, only the heater SH5 on the discharge port 31 side is driven, and the heater SH6 on the liquid chamber 33 side is driven only when discharging large ink droplets. In addition, it is possible to improve the refill frequency when a large ink droplet is ejected.

(Fourth Embodiment) In this embodiment, an ink jet recording head cartridge and an ink jet recording apparatus equipped with the above-described ink jet recording head of the present invention will be described.

FIG. 6 is a schematic perspective view of an ink jet recording apparatus according to a fourth embodiment of the present invention, and FIG. 7 is a perspective view of an ink jet recording head cartridge mounted on the ink jet recording apparatus shown in FIG. It is.

In FIG. 6, a lead screw 52 having a spiral groove 53 is rotatably supported on the main body frame 51. The lead screw 52 is driven to rotate via driving force transmission gears 60 and 61 in conjunction with forward and reverse rotation of a driving motor 59. Further, a guide rail 5 for slidably guiding the carriage 55 is provided on the main body frame 51.
4 is fixed. The carriage 55 has a spiral groove 53
The carriage 55 can be reciprocated in the directions indicated by arrows a and b by rotating the lead screw 52 by the rotation of the drive motor 59. The paper pressing plate 72 presses the recording medium 90 against the platen roller 73 over the moving direction of the carriage 55.

An ink jet recording head cartridge 80 is mounted on the carriage 55. As shown in FIG. 7, the ink jet recording head cartridge 80 includes an ink jet recording head 81 provided with a heater as described in the first to third embodiments, and an ink supplied to the ink jet recording head 81. An ink tank 83 to be stored is integrated with the ink tank 83, and is mounted on the carriage 55 so that the arrangement direction of the ejection ports 82 of the inkjet recording head 81 is perpendicular to the reciprocating direction of the carriage 55.

The ink jet recording head cartridge 80 is fixed to and held on the carriage 55 by positioning means and electric contacts provided on the carriage 55, and is detachably mounted on the carriage 55.

The photocouplers 57 and 58 are connected to the carriage 5
The home position detecting means for confirming the presence of the lever 56 in this region in this region and performing reverse rotation of the rotation direction of the drive motor 59 and the like is constituted. A cap member 67 for capping the front surface of the ink jet recording head 81 (the surface on which the discharge port 82 is opened) is supported by the support member 62 and further includes a suction unit 66. Perform recovery. A support plate 65 is attached to the main body support plate 64, and the cleaning blade 6 slidably supported by the support plate 65.
3 is moved in the front-rear direction by driving means (not shown). The configuration of the cleaning blade 63 is not limited to the illustrated one, and it is needless to say that a known blade can be applied. The lever 70 is used to start the suction recovery operation of the ink jet recording head 81, and moves with the movement of the cam 71 in contact with the carriage 55.
From 9, the driving force is controlled by known transmission means such as gear and clutch switching.

The capping, cleaning, and suction recovery processes are performed at corresponding positions by the action of the lead screw 52 when the carriage 55 moves to the home position side area. If a desired operation is performed at a known timing, any of the embodiments can be applied.

The ink jet recording apparatus described above has recording signal supply means for supplying a recording signal for driving the heater of the mounted ink jet recording head 81 to the ink jet recording head 81, and controls the operation of the ink jet recording apparatus. It has a part. In addition,
The inkjet recording apparatus may be for a single-heater inkjet recording head or for a multi-heater inkjet recording head. However, in the case of a single-heater ink jet recording head, it is not possible to control the drive of the heater so as to switch between ejection of small ink droplets and ejection of large ink droplets, and only large ink droplets are ejected by simultaneous driving of two heaters. .

The ink jet recording apparatus of the present embodiment
Ink jet recording head 81 having trapezoidal heater
Since the ink ejection speed is improved, the ink ejection direction is stable, and high-quality images can be recorded, and the ink refill frequency is improved. It becomes possible. In the present embodiment, an example is shown in which the ink jet recording head cartridge 80 is detachably mounted on the carriage 55. However, the present invention is not limited to this, and the ink jet recording head is integrally mounted on the carriage 55, and only the ink tank is detachably mounted. It may be configured to be mounted.

[0054]

As described above, according to the present invention, at least one of the plurality of electrothermal transducers provided in the flow path of the ink jet recording head of the multi-heater has a trapezoidal shape, so that small droplets can be reduced. The discharge characteristics such as the discharge speed and the refill frequency can be improved while enabling the gradation expression using large droplets. In addition, since it becomes easy to design the discharge characteristics when each electrothermal transducer is driven at the same time as a single-heater inkjet recording head, it is possible to have compatibility with a single-heater inkjet recording head. .

Further, since the ink jet recording apparatus of the present invention is equipped with the above ink jet recording head of the present invention, it is possible to record high-quality images and the like and to perform high-speed recording.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an ink flow path portion of an ink jet recording head according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a difference between a process of growing bubbles and a process of eliminating bubbles between a trapezoidal heater and a rectangular heater.

FIG. 3 is a schematic cross-sectional view of an ink flow path portion of an ink jet recording head in which two heaters are rectangular heaters in order to compare a refill frequency with the ink jet recording head shown in FIG.

FIG. 4 is a schematic sectional view of an ink flow path portion of an ink jet recording head according to a second embodiment of the present invention.

FIG. 5 is a schematic sectional view of an ink flow path portion of an ink jet recording head according to a third embodiment of the present invention.

FIG. 6 is a schematic perspective view of an ink jet recording apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view of an ink jet recording head cartridge mounted on the ink jet recording apparatus shown in FIG.

[Explanation of symbols]

11, 21, 31, 82 Discharge ports 12, 22, 32 Ink flow paths 13, 23, 33 Liquid chambers SH1, SH2, SH3, SH4, SH5, SH6
Heater (electric heat conversion element) 51 Body frame 52 Lead screw 54 Guide rail 55 Carriage 59 Drive motor 60, 61 Driving force transmission gear 72 Paper press plate 73 Platen roller 80 Ink jet recording head cartridge 81 Ink jet recording head 83 Ink tank 90 Recording Medium

Claims (9)

[Claims] 1. A plurality of electrothermal conversion elements that can be driven independently of each other are provided in a flow path to which liquid is supplied, and the liquid in the flow path is foamed by driving the electrothermal conversion elements. In an ink jet recording head for discharging liquid from a discharge port opened in the flow path, at least one of the plurality of electrothermal transducers has a width of an end on the discharge port side and an end on an opposite side to the discharge port. An ink jet recording head having a trapezoidal shape in which the width of a portion is different. 2. The ink jet recording head according to claim 1, wherein said trapezoidal electrothermal transducer has a width at an end on the discharge port side larger than a width at an end on a side opposite to the discharge port. 3. The ink jet recording head according to claim 1, wherein the width of the trapezoidal electrothermal transducer is smaller at the end on the discharge port side than at the end on the side opposite to the discharge port. 4. The flow path is provided with two of the electrothermal transducers, one of the electrothermal transducers has a rectangular shape, and the other electrothermal transducer has a shape closer to the end on the discharge port side. 2. The ink jet recording head according to claim 1, wherein the width of the portion is a trapezoid smaller than the width of an end opposite to the discharge port. 5. The flow path is provided with two of the electrothermal conversion elements, and one of the electrothermal conversion elements has a shape in which the width of the end on the discharge port side is the end on the side opposite to the discharge port. The shape of the other electrothermal transducer is a trapezoid whose width at the end on the discharge port side is smaller than the width at the end on the side opposite to the discharge port. The inkjet recording head according to the above. 6. The ink jet recording head according to claim 5, wherein the one electrothermal conversion element is arranged at a position closer to the discharge port than the other electrothermal conversion element. 7. An ink jet recording head cartridge comprising: the ink jet recording head according to claim 1; and a tank for storing a liquid to be supplied to the ink jet recording head. 8. The inkjet recording head according to claim 1, further comprising: a recording signal supply unit that supplies a recording signal for driving the inkjet recording head to the inkjet recording head. An ink jet recording apparatus that performs recording by discharging liquid from a discharge port of the ink jet recording head based on a recording signal. 9. A carriage on which the ink jet recording head cartridge according to claim 7 is removably mounted.
Recording signal supply means for supplying a recording signal for driving an ink jet recording head of an ink jet recording head cartridge mounted on the carriage to the ink jet recording head, wherein a liquid is supplied from a discharge port of the ink jet recording head based on the recording signal. An ink jet recording apparatus that performs recording by discharging ink.