JPH06255132A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To miniaturize the title apparatus and to enable multivalue gradation recording at a high recording speed by providing a recording means driving the ink droplets emitted from a plurality of emitting orifices different in emitting quantity in the same pixel 6f a receiving medium. CONSTITUTION:For example, ink droplets each having a volume of 17 pl are emitted from emitting orifices L by one emission and, for example, ink droplets having a volume 7 pl are emitted from emitting orifices M while, for example, ink droplets each having a volume of 4 pl are emitted from emitting orifices S. A recording head 1 performs scanning in an X-direction to perform recording and, when the recording of one line is completed, recording paper or the recording head 1 is relatively scanned in a Y-direction by a distance D and, continuously, the recording of a next line is performed. Therefore, noticing each pixel, the ink droplets emitted from the respective emitting orifices of emitting orifice groups L, M, S can be driven in and superposed one upon another to form a pixel. Therefore, multivalue gradation recording can be performed at a high recording speed.

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 apparatus, and more particularly to an ink jet recording apparatus for performing multivalue recording.

[0002]

2. Description of the Related Art In general, an ink jet recording apparatus of this type has an extremely small noise generation at the time of recording, is capable of high-speed recording, and records on plain paper without requiring a special fixing process. Since it can be done, it has been attracting attention recently. Various types of devices have been proposed for this device. In such an ink jet recording apparatus, in particular, when performing color recording, for example, C (cyan),
M (magenta), Y (yellow) and K (black)
When recording is performed using the color inks, dots such as K and M may be relatively conspicuous in the recorded image and the like, and a granular feeling may remain.

Among such ink jet recording apparatuses, the recording apparatus using the piezo method can relatively easily solve the above problems. That is, in the piezo type recording apparatus, since the voltage or pulse width of the pulse applied to the piezo element can be modulated to change the ejected ink amount, it is possible to reduce the granular feeling due to the ink dots to be recorded. Becomes

However, the piezo method has a problem that it is difficult to integrate the ejection ports with high density because it is necessary to provide a piezo element for each ejection port.

On the other hand, in the method in which flying droplets are formed by bubbles generated in the recording liquid by utilizing thermal energy, the ejection openings can be arranged at a high density, and therefore recording with high resolution can be performed. Is also possible. Further, there is an advantage that it is easy to make the recording head compact as a whole. In addition, since this type of recording head can be manufactured by fully utilizing the advantages of IC technology and micro processing technology, which have been significantly improved in technology and reliability in recent semiconductor fields, they can be manufactured with multi-nozzles and high-density mounting. It is easy to commercialize, and the productivity in mass production is good and the manufacturing cost can be reduced.

However, in the recording head of the above-mentioned system, the ejection amount in one ejection is relatively small even if the supply amount of thermal energy to be applied is changed.

Therefore, the multi-droplet method, the dark and light ink method and the like have been conventionally known as a method for significantly controlling the ejection amount and the ink concentration of ink droplets ejected once by utilizing thermal energy.

FIG. 8 is an explanatory diagram of a case where four-value recording is performed for the ejection amount by using the multi-droplet method.

In the multi-droplet method, a plurality of ink droplets are landed from the same ejection port into substantially the same pixel of the recording medium to form one dot.

Recording by the multi-droplet method will be specifically described with reference to FIGS. 8 (a) and 8 (b).

In this figure, the intersection of a vertical straight line and a horizontal straight line is the center point of each pixel. The ink amount of one droplet of the ink jet recording head is one of the two-value recording in the four-value recording in consideration of the time when the ink droplets are not ejected.
/ 3. When the multi-droplet method is performed with four-value recording, a maximum of three ink droplets are ejected from the same ejection port, so the drive frequency is three times the normal drive frequency.

The number of droplets recorded in each pixel is three (FIG. 8A) depending on the density to be expressed.
A), 2 (B in FIG. 8A), 1 (C in FIG. 8A), and 0. Since the time required for the recording paper to absorb the ink is much slower than the ejection interval of the ink droplets, the ink droplets on the recording paper are integrated before being absorbed, and as shown in FIG. The dots have different sizes. In this way, the dot size changes and multi-value recording is performed.

On the other hand, in the dark and light ink method, a plurality of recording heads for ejecting ink droplets having different densities are prepared, and a recording head for ejecting ink droplets is selected according to the density to be expressed. is there.

[0014]

However, each of the above methods has the following problems.

In the case of the multi-droplet method, in order to perform n-value recording, the ejection frequency of the recording head needs to be (n-1) times the pixel frequency. Here, when the ejection frequency of the recording head is the same as that of the conventional one, the recording speed is reduced to 1 / (n-1).

Further, in the dark and light ink method, it is necessary to provide (n-1) recording heads and inks having different densities in order to perform n-value recording, and the apparatus becomes large and complicated.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide an ink jet recording apparatus having a high recording speed.

Another object of the present invention is to provide an ink jet recording apparatus in which the apparatus is downsized and simplified.

[0019]

In order to achieve such an object, an ink jet recording apparatus of the present invention uses a recording head having a plurality of ejection ports which eject different amounts of ink from each other, and An inkjet recording device for recording by ejecting ink droplets onto a recording medium,
A moving unit that relatively moves the recording head and the recording medium, and a plurality of ejection ports that control the movement of the moving unit and the ejection amount of ink from the recording head, and that eject the ink amounts different from each other. And a recording control unit for ejecting the ink droplets into the same pixel of the recording medium.

[0020]

According to the present invention, ink droplets are ejected into the same pixel of a recording medium by using a recording head having a plurality of ejection ports which eject different amounts of ink from each other. Key record can be performed.

[0021]

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

Embodiment 1 FIG. 1 is a front view of a recording head used in an embodiment of the present invention.

The recording head 1 shown in FIG. 1 has a total of 1 discharge port, each having 6 openings in the vertical direction in the drawing.
Eight are provided. In the figure, an ink droplet having a volume of 17 pl is ejected from the ejection port indicated by L (Large) in one ejection, and an ink droplet of 7 pl is ejected from the ejection port indicated by M (Middle), and 4p from the discharge port indicated by S (Small)
l ink droplets are ejected. Recording head 1
Prints while scanning in the X direction in the figure, and when printing for one line is completed, the recording paper or print head is relatively scanned in the Y direction by the distance indicated by D in the figure, and then the next Record the line.

Therefore, paying attention to each pixel, it becomes possible to drive the ink droplets ejected from the ejection ports of the ejection port group L, the ejection port group M and the ejection port group S, respectively. The droplets can be stacked to form pixels.

Table 1 shows the relationship between the combination of the presence or absence of ejection at each ejection port and the total amount of ink ejected to each pixel in the above case.

[0026]

[Table 1]

As can be seen from Table 1, the total amount of ink recorded in each pixel varies within the range of 0 to 28 pl, and recording having a total of eight gradation levels can be performed.

FIG. 2 is a block diagram showing an image signal processing system which can be used in this embodiment.

The multi-valued input image signal 2 is stored in the table ROM 3
When input to, the signal is converted into a 3-bit signal for each pixel. That is, from the table ROM3, the discharge port group S
, A bit signal 4 indicating whether to print, a bit signal 5 indicating whether to print from the ejection port group M, and a bit signal 6 indicating whether to print from the ejection port group L are output.
The buffer 7 is a FiF that temporarily stores a bit signal for one scan.
O (First in First Out), the buffer 8 is a FiFO that temporarily stores bit signals for two scans. Therefore, the signal 9 becomes a recording signal of the ejection port group M sent by one scan from the signal 4 of the ejection port group S. Similarly, signal 1
0 is a recording signal of the ejection port group L delayed by two scans.

These signals 4, 9 and 10 are combined in the data combining section 11, and the combined signal 12 is transmitted to the recording head 13. As a result, ink droplets are ejected from the ejection ports of each ejection group, and as described with reference to FIG. 1, the relative movement of the distance D between the recording paper and the recording head and the scanning in the X direction cause each ejection port group L in each pixel. , M and S, the ink droplets can be stacked and driven.

As described above, according to the configuration of this example, 8-value recording can be easily performed. When 8-value recording is performed using the simple multi-droplet method, the recording speed is reduced to 1/7 as compared with the recording without multi-droplet, but in the present embodiment, the recording is performed three times for 8-value recording. The scanning speed is only 1/3 because it only scans
It only needs to be reduced to.

Further, in the dark and light ink method, which is one of the gradation expression methods, it is necessary to use a large number of recording heads for ejecting inks having different densities, but this is not necessary in the present embodiment, so the apparatus is downsized. And simplified.

Embodiment 2 In this embodiment, the recording method of Embodiment 1 is applied to the multi-droplet method.

In this embodiment, a plurality of ink droplets are ejected from each ejection port of the recording head having the structure shown in FIG. 1 and landed in the same pixel. For example, when four-value recording is performed by the multi-droplet method with the pixel frequency being 1/3, the ejection port group S, the ejection port group M, and the ejection port group L
Since four-value recording can be performed from each of the ejection ports, the gradation of 4 × 4 × 4 = 64 can be expressed as a whole. The recording speed at this time is (pixel frequency) x (ejection frequency) compared to the case of performing normal recording.
= (1/3) × (1/3) = 1/9. On the other hand, when the same number of gradations is realized by using the multi-droplet method, the recording speed is 1/63, which is extremely high in comparison with this.

Example 3 In this example, the present invention is applied to full-color recording.

In this case, four recording heads for ejecting ink droplets of different colors of cyan (C), magenta (M), yellow (Y) and black (K) are prepared with the configuration shown in FIG. Then, the recording head is arranged in the main scanning direction, that is, the X direction.

Full-color recording is performed by using recording heads for ejecting these four color inks, respectively.

At this time, for example, in the case of reproducing red (R) by mixing M and Y, it is necessary to perform masking because the Y component in the M ink becomes excessive. When the ink has three colors of C, M and Y, the under color removal (U
CR) to replace the gray component with the black signal.
Furthermore, it is necessary to perform gradation correction such as γ correction and contrast correction, and edge enhancement as necessary.

After performing such color processing, C, M,
The signals of Y and K, or C, M and Y are processed as shown in FIG. 2, and ink droplets are ejected from the recording heads onto the recording paper to perform overprinting. Also in the present embodiment, as in the first embodiment, by using the recording heads having different ejection opening areas of the ejection opening group L, the ejection opening group M, and the ejection opening group S, for example, by moving the recording paper, the maximum Overprinting can be performed in the same pixel three times. For this reason, the recording speed can be reduced to 1/3 as compared with the case of full-color recording in which the areas of all the ejection openings are the same.

Embodiment 4 In this embodiment, as a structure for ejecting ink droplets having different ejection amounts by utilizing thermal energy, the ejection amount is changed by changing the distance between the ejection heater and the orifice. It is what makes me.

FIG. 3 is a sectional view showing a schematic structure of the ink jet recording head used in this embodiment.

In the figure, for example, an electrothermal conversion element (ejection heater) 20 for generating energy for ejecting ink and an electrode 21 for supplying electric power to the ejection heater 20 are formed on a silicon substrate. Formed by membrane technology. Here, the discharge heater 20 is, for example, HfB ₂
Is used as a heating resistor.

In this structure, when electricity is supplied in accordance with the recording signal, the discharge heater 20 generates heat to generate bubbles in the ink in the ink liquid path 23. As a result of the generation of the bubbles, ink is ejected from the orifice 22. Droplets are ejected.

At this time, the amount of ink to be ejected depends on the volume of the ink column existing between the ejection heater 20 and the orifice 22.

In this embodiment, instead of the discharge port group L, the discharge port group M and the discharge port group S of the first embodiment, the distance between the orifice 22 and the discharge heater 20 is set to d ₁ , d ₂ and A recording head having d ₃ (d ₁ > d ₂ > d ₃ ) is prepared. By doing so, the amount of ink droplets ejected from the orifice 22 changes, and eight values can be expressed as in the first embodiment. When expressing 8 gradations in the recording without the multi-droplet method,
Although the recording speed is reduced to 1/7, the recording speed can be reduced to 1/3 in this embodiment.

Further, according to this embodiment, it is not necessary to reduce the area of the ejection port to reduce the ejection amount, and the distance d can be shortened, so that clogging due to minute dust or thickened ink does not occur. Hard to wake up.

Embodiment 5 FIG. 4 is a front view showing a schematic structure of a recording head according to this embodiment.

In this embodiment, as shown in the first embodiment, the ejection port group L, the ejection port group M, and the ejection port group S are not arranged in one recording head, but ejection port groups having different areas are arranged. Three recording heads La, Lb, and Lc are arranged in a zigzag pattern in the Y direction (sub-scanning direction).

These recording heads La, Lb and Lc
Are sequentially recorded while moving in the X direction (main scanning direction). The present embodiment differs from the first embodiment in that the print heads of the ejection port groups are arranged in a staggered manner, and the scan of the print heads is the same as that of the first embodiment. Therefore, the print heads La, Lb and L are scanned.
Using c, it is possible to perform overprinting up to three times within the same pixel.

Similar to the first embodiment, eight gradations can be expressed by superposing the inks ejected from the recording heads La, Lb and Lc. In the simple multi-droplet method, the recording speed is reduced to 1/7 when 8-value recording is performed, but in the present embodiment, since recording can be performed by scanning the recording head three times, the recording speed is reduced to 1/3. Just do it.

In this embodiment, since the discharge ports having the same area can be processed separately, the first embodiment
As described above, there is an advantage that the manufacturing process is simplified and the yield is improved as compared with the case where the recording heads having different ejection openings are manufactured.

Embodiment 6 FIG. 5 is a front view showing a schematic structure of a recording head according to an embodiment of the present invention.

In the fifth embodiment, the recording heads are arranged in a zigzag pattern, but in this embodiment, three recording heads La, Lb and Lc are arranged in parallel in the Y direction.

The recording heads La, Lb, and Lc respectively have ejection port groups L, L of the first embodiment corresponding to the areas of the ejection ports.
It corresponds to the ejection port group M and the ejection port group S.

The recording heads La and Lb having the above-mentioned structure
By scanning Lc and Lc in the X direction, recording for one line is performed. As a result, it is possible to perform repeated hits up to three times in one scan.

Further, in this embodiment, eight gradations can be expressed by one scanning as compared with the first embodiment.

In this embodiment, the capacities of the buffer 7 and the buffer 8 shown in FIG. 2 are not the capacities for one scan and two scans, respectively, but the capacities corresponding to the distances between the recording heads. I'm done.

Further, in this embodiment, the discharge amount was made different in the area of the discharge port, but as described in the fourth embodiment, the discharge amount is changed by changing the distance between the discharge heater and the orifice. Of course, it may be done.

Embodiment 7 In the above embodiments, description has been made on the assumption that the volume of ink droplets ejected from one ejection port is constant, but the present invention is not limited to this. .

For example, when it is not always necessary to downsize the apparatus, it is also possible to provide one recording head having a different ejection opening area and to make the amount of ink droplets ejected from this recording head variable. To be In this case, for example, a piezo element can be used as the element that generates the energy used for ejection, and the degree of contraction of this element can be directly modulated to, for example, three types.

At this time, since four-value recording is possible,
The number of gradations is 4 × 4 × 4 = 64, and 64 gradations can be expressed.

FIG. 6 is a schematic perspective view showing the main part of the ink jet recording apparatus used in the present invention.

In FIG. 6, the recording head 101 is provided with an ejection port group L, an ejection port group M, and an ejection port group S on the surface facing the recording paper 107 in a direction perpendicular to the conveyance direction of the recording paper 107. Get Further, the recording head 101 is provided with an ink path (not shown) in communication with each of these ejection port groups, and the recording head 1 corresponds to each ink path.
An electrothermal converter that generates thermal energy for ejecting ink is formed on the substrate forming 01. The electrothermal converter generates heat by an electric pulse applied to it according to drive data, which causes film boiling in the ink, and the ink is ejected from the ejection port as bubbles are generated by the film boiling. To be done. Each ink path is provided with a common liquid chamber that communicates with them in common, and the ink stored therein is supplied to the ink path according to the ejection operation in each ink path.

The carriage 102 carries the recording head 101, and slidably engages with a pair of guide rails 103 extending parallel to the recording surface of the recording paper 107. As a result, the recording head 101 can move along the guide rail 103, and recording is performed by ejecting ink toward the recording surface at a predetermined timing with this movement. After the above movement, the recording paper 107 is conveyed by a predetermined amount in the direction of the arrow in the drawing, and the above movement is performed again to perform recording. By repeating such an operation, the recording paper 10
In 7, we will record sequentially.

The above-described conveyance of the recording paper 107 is performed by a pair of conveying rollers 1 arranged above and below the recording surface.
This is done by rotating 04 and 105. A platen (not shown) for maintaining the flatness of the recording surface is provided on the back side of the recording surface of the recording paper 107.

The carriage 102 can be moved by driving a motor, for example, a belt (not shown) attached to the carriage 102. Further, the conveyance rollers 104 and 105 are also rotated by the motor. It becomes possible by being transmitted to.

FIG. 7 is a block diagram showing the control arrangement of the ink jet recording apparatus shown in FIG.

In FIG. 7, the CPU 100 executes control processing, data processing, etc. of the operation of each part of the device based on the signal sent from the host device. The ROM 100A stores the processing procedure and the like, and the RAM 100B is used as a work area for executing the above processing.

Ink ejection in the recording head 101 is
This is performed by the CPU 100 supplying drive data and drive control signals for the electrothermal converter to the head driver 1A. The CPU 100 also includes a carriage motor 20 and a conveyance roller 1 for moving the carriage 102.
Paper feed for rotating 04 and 105 F. The rotation of the motor 50 is controlled by the motor drivers 20A and 5A, respectively.
Control via 0A.

(Others) The present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention brings about excellent effects in a recording head and a recording apparatus of the type in which the state of ink is changed by the heat energy. This is because such a system can achieve high density recording and high definition recording.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely 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 which can be recorded by the recording apparatus. 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 recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the electrical connection to the main body of the apparatus or the ink from the main body of the apparatus by being mounted on the main body of the apparatus. 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 integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add the ejection recovery means of the recording head, the preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single-color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying thermal energy such as ink that is liquefied by applying thermal energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. 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, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function are provided. It may be a form or the like.

[0079]

As described above, according to the present invention,
Since ink droplets are ejected into the same pixel of a recording medium by using a recording head having a plurality of ejection ports that eject different amounts of ink from each other, it is possible to perform multi-value gradation recording at an increased recording speed.

Further, according to the present invention, since the dark and light ink method is not used, there is an advantage that the ink jet recording apparatus is downsized and the structure is simplified.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration of a recording head used in a first embodiment of the present invention.

FIG. 2 is a block diagram of an image signal processing system used in the first embodiment of the present invention.

FIG. 3 is a sectional view of a recording head used in a fourth embodiment of the present invention.

FIG. 4 is a block diagram showing a schematic configuration of a recording head used in a fifth embodiment of the present invention.

FIG. 5 is a front view showing the configuration of a recording head used in a sixth embodiment of the present invention.

FIG. 6 is a perspective view showing a schematic configuration showing a main part of an inkjet recording apparatus used in the present invention.

7 is a block diagram showing a control configuration of the inkjet recording apparatus shown in FIG.

FIG. 8 is an explanatory diagram for explaining the principle of the multi-droplet method.

[Explanation of symbols]

 1 recording head 2 input image signal 3 table ROM 4, 5, 6-bit signal 7, 8 buffer 9, 10 signal 11 data synthesizing section 12 signal 101 recording head

Claims (4)

[Claims] 1. An ink jet recording apparatus for recording by using a recording head having a plurality of ejection openings each of which ejects a different amount of ink and ejecting ink droplets from the recording head onto a recording medium. Moving means for moving the head and the recording medium relative to each other; controlling the movement of the moving means and the ejection amount of ink from the recording head; An inkjet recording apparatus, comprising: a recording control unit for ejecting a droplet into the same pixel of the recording medium. 2. The ink jet recording apparatus according to claim 1, wherein the plurality of ejection openings having different amounts of ejected ink have different opening areas. 3. The ink jet recording apparatus according to claim 1, wherein the recording head has an electrothermal conversion element that generates thermal energy used to eject ink droplets. 4. The ink jet recording apparatus according to claim 1, wherein the plurality of ejection ports having different amounts of ejected ink have different distances between the respective ejection ports and the electrothermal conversion element. .