JPH04361051A - Ink jet recording - Google Patents

Abstract

PURPOSE:To obtain images in high gradation without streaks and unevenness by a method wherein a recording head is so arranged that an array of nozzles thereof becomes slant against scanning lines, and one pixel is formed by ejection of a plurality of ink droplets ejected respectively from different ejection ports. CONSTITUTION:The scanning direction over a material 2 on which recording is made and the arrangement direction of ink ejection ports of a recording head 101 are set at a specified angle, being not in parallel with each other. Under such condition, the recording is executed by making the material 2 on which the recording is made and the recording head 101 make relative movement so that ink droplets are ejected from each of the ink ejection ports of the recording head 101 to one pixel. Thereby images in high gradation without streaks and unevenness can be obtained even though there is nonuniformity among characteristics of respective ink ejection ports.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording method, and more particularly to an inkjet recording method for forming an image with gradation using a recording head having a plurality of ink ejection ports.

0002

2. Description of the Related Art The inkjet recording method is a method in which ink is ejected from an ink ejection opening (hereinafter referred to as a nozzle) in response to a recording signal to visualize an image on a recording material (recording paper). Generally, in order to perform high-speed printing, ink is ejected from a print head that is integrally formed with a large number of nozzles. In this case, a structure in which a large number of nozzles are arranged in a straight line is relatively easy to manufacture in terms of manufacturing technology, and the nozzles can be arranged at high density.

[0003] In particular, when recording color images, usually yellow, magenta, and cyan (black if necessary) are used.
A nozzle is used to eject each ink.

[0004] When attempting to express gradation using this inkjet recording method, it is sufficient to change the size of the ejected droplets, but there is no established method for this, and generally known methods are used. Image processing technology is used to control the number of dots printed per unit area. There is also a method of expressing gradation by reducing the size of one ink droplet and ejecting a large number of ink droplets at approximately the same position, and controlling the number of ejections. According to this method, the resolution Gradation recording can be performed without reducing the gradation.

[0005]

[Problems to be Solved by the Invention] In order to perform high-speed recording, it is effective to increase the number of nozzles, but increasing the number of nozzles increases the width of recording that is recorded at one time.
As a result, image density becomes uneven due to minute differences in the ejection characteristics of each nozzle.

According to experiments conducted by the inventors of the present application, even a change of only a few percent in the amount of ink ejection is recognized as unevenness in the image, which is a serious drawback when recording images with gradation. Become.

[0007] In particular, in the method of controlling the gradation by ejecting a large number of ink droplets at approximately the same position on recording paper, it is necessary to eject an extremely large number of ink droplets to record one image. However, since there is a limit to increasing the driving frequency of each nozzle, it is essential to increase the number of nozzles, and it is difficult to prevent density unevenness in images that occurs in this case.

In addition, in the method of ejecting a large number of ink droplets at approximately the same position, it is necessary to make each ink droplet small, but even if a large number of ink droplets are ejected for this purpose, the recording material The ink smears on the top are smaller,
A minute error in the implantation position may cause a gap between adjacent recording pixels, which may cause streaks in the obtained image.

[0009] In order to prevent the occurrence of such streaks,
Although it is desirable to deposit a large number of ink droplets in an overlapping manner while shifting them by a minute amount in the vertical and horizontal directions, conventionally, such control has been difficult.

SUMMARY OF THE INVENTION Therefore, in view of the above-mentioned points, an object of the present invention is to provide an inkjet recording method suitable for increasing the density of ink ejection ports and obtaining gradation images without streaks or unevenness. be.

[0011]

Means for Solving the Problems The present invention provides an inkjet recording method for forming a gradation image using a recording head having a plurality of ink ejection ports. The recording material and the recording head are set so that the ejection opening arrangement direction is non-parallel with a predetermined angle, and ink droplets are ejected from each ink ejection opening included in the recording head to the same pixel. This is to record by moving them relatively.

More specifically, the present invention provides an inkjet recording method that expresses gradation by ejecting a plurality of ink droplets overlappingly within a predetermined pixel.
When arranging a recording head having at least one row of ejection orifices in which ink ejection orifices are arranged substantially in a straight line to face a recording material, the scanning By arranging the line and the recording head and moving the recording head and the recording material relatively, a maximum of M shots (M=N/L) of ink liquid per one ejection opening arrangement can be applied to the same pixel. Droplets are ejected from different ink ejection ports making up the ejection port array.

Here, when the pitch of the scanning lines is A, it is preferable to set A×L to 0.5 mm or less, or to set L to 8 or less.

[0014]

According to the present invention, by arranging the ink ejection orifice rows of the recording head diagonally, the area covered by the plurality of ink ejection orifices becomes only the width of a predetermined number of scanning lines. By shifting the relative position of the recording head and recording material (recording paper), ink is ejected from different ink ejection ports to the same pixel, so the characteristics of each ink ejection port may vary slightly. Even if there are streaks, it is possible to make the streaks on the image less noticeable.

Regarding claim 2, according to the present invention, although printing is performed using a printing head having N ink ejection ports, the width that is printed at one time is only L scanning lines. Therefore, even if the density of the image is uneven due to variations in the ejection characteristics of each ejection port, the streaks will not be noticeable because the recording width of L scanning lines is repeated over the entire image.

According to research conducted by the inventors of the present application, it has been found that unevenness in image density generally becomes easier to recognize as the recording width becomes wider. For example, 1 per mm
When viewing an image composed of about 6 pixels at a clear vision distance, if the unevenness is about 8 mm wide, even a few percent change in density will be recognized as unevenness, but if the width is about 1 mm or less, it will be recognized as unevenness. In this case, even density fluctuations of several tens of percent or more can be visually tolerated.

As described above, according to the present invention, since the width of printing at one time is as small as L scanning lines, the width of density unevenness caused by variations in ink ejection ports, etc. is reduced to an almost tolerable level. can do. Moreover, even though the width recorded at one time is small, the recording speed does not become slow.

Furthermore, according to the present invention, since a plurality of ink ejection ports are used to form one pixel, even if there are variations in the characteristics of each ejection port, the This has the effect of averaging and reducing variations, which also suppresses image unevenness.

[0019]

EXAMPLES Examples of the present invention will be described in detail below.

Example 1 FIG. 1 is a schematic external view showing an example of an inkjet recording apparatus to which the present invention is applied.

In this embodiment, a recording paper 2, which is a recording material, is wound around a drum 4, and is rotated by a drive device 6. The recording head 101 is arranged so that its nozzle array is slightly oblique (that is, not parallel) to the main scanning direction formed by the rotation of the recording paper 2 .

[0022] When recording a full-color image, three (yellow, magenta, cyan) or four (additional black) recording heads are used (not shown), and color ink is applied from each recording head. Discharge and record.

The recording head 101 performs recording while moving from left to right in the sub-scanning direction by a head driving device (not shown).

FIG. 2 shows a schematic configuration of a control system circuit in the embodiment shown in FIG. Here, 201 is a main controller that controls the entire device such as discharge timing, and includes, for example, a CPU (central processing unit), a program ROM (read only memory), and a work RA.
A one-chip microprocessor or the like having a built-in M (random access memory) or the like is usually used. The main controller 201 sends the gradation data signal to the host computer 20.
3 and stores it in frame memory 205 for buffering in units of frames. When recording an image (when discharging ink), the main controller 201 controls the carriage feed motor 209 through the first motor driver 207.
and controls the driving of the paper feed motor 213 through the second motor driver 211. Based on the gradation data read from the frame memory 205, the driver controller 215 and the head driver 217
Ejection control of the head 101 (described in detail below) is performed via the head 101, thereby recording a gradation image on the recording paper 2.

FIG. 3 shows the relative positional relationship between the recording paper 2 and the nozzle array included in the recording head 101. In this figure, a-17 to a+2 written on the left side of the figure indicate pixel numbers in the main scanning direction on the recording paper. Further, vertical lines b+1 to b+4 indicate main scanning lines formed by the rotation of the drum 4.

In this embodiment, the recording head 101 has 20 nozzles, and each rotation of the drum 4 causes ink droplets to land on four scanning lines (more precisely, on and around the lines). let In other words, the 20 nozzles linearly provided in the recording head 101 are arranged so that the arrangement direction is oblique to the main scanning direction, and the ink landing area ( The impact position is on and around the four main scanning lines.

As described above, since the nozzle array (discharge port array) of the recording head is arranged to form a slight angle with the main scanning line, the actual pitch PN between the nozzles is approximately 2% smaller than the pixel pitch PP. It has become somewhat longer. That is,
Since the recording paper moves by one pixel pitch in the direction of the arrow each time each nozzle of the recording head repeatedly discharges droplets, the nozzle pitch in the main scanning direction matches the pixel pitch.

In this case, as an example, the repeat droplet ejection frequency per nozzle of the recording head is 10 kHz, and the pixel density is 1.
Assuming 16 pieces per mm, the pixel pitch PP is 62.
5 μm, and the nozzle pitch PN is 63.7 μm.
The speed of the recording paper is 0.625 m/sec.

In this embodiment, five ink droplets are ejected per pixel in the highest density area. Therefore, 5
It is possible to record six levels of gradation: 1 shot, 4 shots, 3 shots, 2 shots, 1 shot, and 0 shots.

The process of performing such six-step gradation recording will be described in detail below.

First, nozzle number 1-1, 1 shown in FIG.
-2, 1-3, 1-4, 1-5, etc. will be explained. Of these nozzle numbers (x-y), x indicates which main scanning line the pixel corresponds to. That is, x=1 corresponds to a nozzle for forming pixels on main scanning line b+1, and x=2 corresponds to a nozzle for forming pixels on main scanning line b+2 (hereinafter omitted).

Further, among the nozzle numbers (x-y), y represents the nozzle used when ejecting ink droplets from ``y'' (y≦5 in this example), and the number of ink droplets is It does not represent the ejection order. For example, main scanning line b+
When three ink droplets are to land at the position of pixel number a-1 on Nozzle 1, first the first ink droplet is ejected from nozzle 1-3, and then the recording paper is moved in the direction of the arrow. The recording paper is moved by one pixel pitch in the direction of the arrow to eject the second ink droplet from nozzle 1-1, and the recording paper is further moved by one pixel pitch in the direction of the arrow to eject the third ink droplet from nozzle 1-2. ink droplets are ejected. In this way, the ink is landed as shown in FIG. 4(C).

Furthermore, in order to eject five ink droplets as shown in FIG. At the same time, ink is ejected in the order of nozzles 1-3, 1-1, 1-2, and 1-4.

Next, other specific examples of ink ejection control will be described in detail with reference to FIGS. 5 to 11. In each of these figures, small circles indicate nozzle positions, and large circles indicate landing marks (dots or ink dots) of ink droplets.

The ink ejection states shown in FIGS. 5 to 11 are as follows:
This figure shows an ejection sequence when forming a maximum density pattern (5 ink ejections per pixel) with a width of 1 pixel and a length of 3 pixels on the main scanning line b+2 in FIG. 3 .

In this way, as shown in FIG. 11, the maximum number of ink droplets (5 shots) are ejected at each position of pixel numbers a, a+1, and a+2. In addition, in each of these figures,
To make the diagram easier to read, the size of the recorded dots relative to the nozzle pitch is drawn much smaller than the actual size.

By controlling the ink ejection as described above and moving the recording head 101 in the sub-scanning direction, an image is printed spread out in the direction perpendicular to the main-scanning direction, and even in high-density areas, there are gaps between scanning lines. Prevents the formation of gaps (streaks).

Note that in FIG. 4, for convenience of explanation, the landing positions are shown as being lined up straight and horizontally, but as is already known, an inkjet recording head having a plurality of nozzles is driven in a time-division manner. is desirable, and in that case, it is also possible to expand the landing positions in the vertical direction by shifting the driving timing between adjacent nozzles.

Further, the pattern of overlapping ink droplets is not limited to this embodiment, and it is also possible to control the ink droplets to be ejected from the nozzles at both ends, for example, when only two ink droplets are ejected.

Furthermore, if the timing of time-division driving is taken into account when designing, the pitch of the nozzles may be slightly changed from this embodiment, and the angle between the nozzle row and the main scanning line may be changed accordingly. can.

According to the research conducted by the present inventors, the ability of human vision to discriminate density generally depends on the period of shading and the roughness (resolution) of the image. If the pixels that make up the image are sufficiently small, the period of shading is several mm.
The discrimination ability is highest when the size is , and even if the size is larger or smaller than that, it becomes inconspicuous.

In particular, the period of light and shade due to image unevenness is 0.
If it is less than 5mm, it will suddenly become inconspicuous and the distance will be 0.5m.
When the period is m, it is possible to identify density unevenness of 4 to 5%, but when the period is 0.3 mm, it is only possible to identify unevenness of about 10% or more. If it is 0.2 mm or less, it will be almost impossible to distinguish, regardless of the degree of density unevenness. On the other hand, 1mm
If the period is , even density unevenness of 2% or less can be identified.

[0043] Although there are individual differences in these discrimination limits,
There are not many individual differences in the tendency toward the cycle.

[0044] When the pixels constituting the image are coarse (low resolution), fine variations in density cannot be identified. If the period of density unevenness is five pixels or less, the difference in density is almost hidden by the roughness of the pixels and is not a problem.

If the period of density unevenness is about 8 pixels, 1
Density unevenness of about 0% can be identified. If the number of pixels is 10 or more, even unevenness of about 5% or less can be identified. This tendency is almost the same when the image is coarser than about 16 pixels per mm. For example, in the case of a rough image with approximately 2 pixels per mm, only the roughness is noticeable when viewed from a close distance, so density unevenness with a small period cannot be identified. In practical terms, such images are viewed from a distance greater than the distance of clear vision. Therefore, the shortest distance for viewing a practical image depends on the roughness of the pixels, and as a result, the discrimination limit for density unevenness is determined by the number of pixels in the image.

Considering the above, in this embodiment, the pitch of the scanning lines is A, and the number of scanning lines recorded simultaneously is L.
When , A x L is 0.5 mm or less, or
If L is set to 8 or less, there will be no problem with the image even if the unevenness due to the difference in ejection characteristics of each nozzle reaches several percent.

Especially in this embodiment, considering that one pixel is recorded by a plurality of nozzles, there is no problem even if the difference in the size of ink droplets ejected from each nozzle is about 10%. You can get beautiful images without any problems.

Furthermore, if the above A×L is selected to be 0.3 mm or less, or if L is selected to be 5 or less, image unevenness due to minute variations in the ejection characteristics of each nozzle becomes almost indistinguishable, and variations in the recording head Regardless of the situation, extremely beautiful images can be obtained.

Embodiment 2 FIG. 12 shows a second embodiment to which the recording method of the present invention is applied. In this embodiment, a recording head 101 is provided on a carriage 50, and recording is performed in synchronization with the movement of the carriage 50, as in a normal serial printer.

L scanning lines are recorded by one movement of the carriage 50, and the recording paper 2 is sent in the direction of arrow A accordingly.

[0051] In this embodiment as well, the recording method is the same as in the first embodiment. Therefore, the recording head 101 is arranged so that its nozzle arrangement direction is substantially horizontal.

In the apparatus of the first embodiment, when a recording head with a very large number of nozzles is used, the distance between the nozzle tips at both ends and the recording paper 2 must be widened.
The size of the recording head that can be used is limited to a relatively small one, but in the apparatus of this embodiment, by making the platen 52 flat, even a large recording head with a relatively large number of nozzles can be used. There are advantages to getting it.

On the other hand, the method using the rotation of the drum (Example 1) is easier to increase the relative movement speed of the recording paper and the recording head than the method using the movement of the carriage (Example 2). The device of Example 1 is suitable for a recording head that has a relatively small number of nozzles and can be driven at high speed.

Example 3 In the third example, the above-mentioned Example 1 or Example 2 is used.
By using a device similar to the above and varying the size of ink droplets ejected from each nozzle, it is possible to increase the number of gradations without increasing the number of overprints.

For example, nozzles 1-1, 2- in FIG.
For Nozzles 1, 3-1, and 4-1, if the volume of ink is approximately twice that of other nozzles is ejected, even if the number of overlapping strokes is the same, depending on the combination of which nozzles are ejected, It is possible to express seven gradations.

In addition, the size of each nozzle is greatly changed, and the volume of droplets discharged from each nozzle is set to a discharge volume ratio of, for example, 1, 1/2, 1/4, 1/8, 1/16. By doing so, 32 gradations can be achieved.

In order to do this, it is sufficient to make the ejection volume of ink droplets different for each nozzle. For example, in an inkjet head system, bubbles are generated in the ink using thermal energy, and the bubbles are removed. When using a method of ejecting ink as it is generated, the size of the heat generating surface of the heater and the opening area of the ejection port may be changed.

Generally, if a nozzle is designed so that the opening area of the nozzle becomes large in order to increase the ejection volume of ink droplets, it is difficult to increase the density of the nozzle arrangement. Since overlapping is performed, the opening area of the nozzle can be designed to be smaller than the conventional one in which overlapping is not performed, making it easy to achieve high density.

Furthermore, in each of the embodiments described so far, it is possible to arrange a nozzle with a relatively small volume of ejected ink droplets adjacent to a nozzle with a relatively large volume of ejected ink droplets. Densification is easy. Here, as a method of making the ejected ink droplet volume different for each nozzle, for example, as described in JP-A-60-27548, the meniscus of all the nozzles is vibrated using a piezo element, and each nozzle is driven. It is also effective to perform this at different timings.

(Others) The present invention particularly relates to means for generating thermal energy as energy used to eject ink, in an inkjet recording system.
For example, the present invention provides an excellent effect in a recording head or recording apparatus that is equipped with an electrothermal converter (for example, an electrothermal converter, a laser beam, etc.) and uses the thermal energy to cause a change in the state of the ink. This is because such a system can achieve higher recording density and higher definition.

For its typical configuration and principle, see, for example, US Pat. Nos. 4,723,129 and 4,740.
Preferably, it is carried out using the basic principles disclosed in the '796 specification. This method is the so-called on-demand type.
It can be applied to any continuous type, but in particular, in the case of an on-demand type, it is applicable to the electrothermal converter placed corresponding to the sheet holding the liquid (ink) or the liquid path. , by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise exceeding nucleate boiling, the electrothermal transducer generates thermal energy to produce film boiling on the thermally active surface of the recording head. As a result, liquid (ink) is generated in one-to-one correspondence with this drive signal.
This is effective because air bubbles can be formed inside. Due to the process of growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening (ejection port) to form at least one droplet. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, making it possible to eject liquid (ink) with particularly excellent responsiveness. As this pulse-shaped drive signal, US Pat. No. 4,463,359
Suitable materials are those described in No. 4,345,262. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

[0062] In addition to the configuration of the recording head, which is a combination of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44 disclose a configuration in which a heat acting part is arranged in a bending region.
A configuration using the specification of No. 59600 is also included in the present invention. In addition, JP-A-59-123670 discloses a configuration in which a plurality of electrothermal transducers have a discharge section having a common slit as a discharge opening, and a hole absorbing pressure wave of thermal energy is disclosed. The effects of the present invention are also effective even with a configuration based on Japanese Patent Application Laid-Open No. 138461/1983, which discloses a configuration in which a discharge portion is provided corresponding to a discharge portion. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.

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

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, etc. to the configuration of the recording apparatus of the present invention, since this further stabilizes the effects of the present invention. Specifically, these include capping means, cleaning means, pressure or suction means for the recording head, electrothermal transducers that generate thermal energy to eject ink droplets necessary for recording, and Preheating means that performs preheating using a different heating element or a combination thereof, and preliminary ejection means that performs ejection other than recording.

Regarding the type and number of recording heads to be mounted, for example, in addition to a single head that corresponds to a single color ink, there are also systems that correspond to a plurality of inks of different recording colors and densities. A plurality of them may be provided. That is, for example, the recording mode of the recording apparatus is not limited to a recording mode for only a mainstream color such as black, but may also be a recording mode in which the recording head is configured integrally or in a combination of multiple colors, Alternatively, the present invention is extremely effective for an apparatus equipped with at least one of the full-color recording modes using color mixing.

[0066] Furthermore, the ejection port array is not limited to one row, but can also be configured to have a plurality of rows (for example, one row has 20 ejection ports, and these are arranged in four rows).

In addition, in the embodiments of the present invention described above, the ink is described as a liquid, but even if the ink solidifies at room temperature or lower, it may be softened or liquefied at room temperature. , can be liquefied and used during recording, so it can be used in the present invention. Alternatively, in the inkjet method, in some cases, the temperature is adjusted so that the ink itself is kept within a range of 30° C. to 70° C., and the temperature is controlled so that the viscosity of the ink is within a stable ejection range. In this case 30℃
An ink that becomes liquid at temperatures above 70° C. or below can be used. In addition, in order to actively prevent the temperature of the ink itself from rising due to thermal energy by using the energy to change the state of the ink from a solid state to a liquid state, or to prevent the ink from evaporating, it is first liquefied by heating. You may also use ink. In any case, the ink is liquefied by the application of thermal energy in accordance with the recording signal, and the liquid ink is ejected, or the ink has already begun to solidify by the time it reaches the recording medium. The present invention is also applicable when using ink that is liquefied for the first time. The ink in this case is
JP-A-54-56847 or JP-A-60-7
The material may be used for recording while being held as a liquid or solid material in the recesses or through holes of a porous sheet, as described in Japanese Patent No. 1260. In the present invention, the most effective method for each of the above-mentioned inks is to perform the above-mentioned method of causing film boiling.

In addition, the inkjet recording device according to the present invention can be used as an image output terminal for information processing equipment such as a computer, a copying device combined with a reader, etc., and a facsimile machine having a sending/receiving function. It may also take the form of a device.

[0069]

As described above, according to the present invention, the print head is arranged so that the nozzle rows of the print head and the scanning line are diagonal, and a plurality of ink droplets are ejected from different ink ejection ports. Since one pixel is formed by the following steps, it is possible to obtain a high-gradation image without streaks or unevenness caused by variations in the amount of ink ejected. Furthermore, since there is a large degree of freedom in designing the amount of ink discharged, it becomes easy to increase the density of the ink discharge ports.

[Brief explanation of drawings]

FIG. 1 is a schematic external view showing an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control unit in an embodiment of the present invention.

FIG. 3 is a diagram illustrating the positional relationship between recording paper, which is a recording material, and a recording head having a plurality of ink ejection ports (nozzles).

FIG. 4 is a diagram showing a state when a plurality of ink droplets land on one pixel in this embodiment.

FIG. 5 is a diagram showing a specific process of ink ejection control.

FIG. 6 is a diagram showing a specific process of ink ejection control.

FIG. 7 is a diagram showing a specific process of ink ejection control.

FIG. 8 is a diagram showing a specific process of ink ejection control.

FIG. 9 is a diagram showing a specific process of ink ejection control.

FIG. 10 is a diagram showing a specific process of ink ejection control.

FIG. 11 is a diagram showing a specific process of ink ejection control.

FIG. 12 is an external view showing an inkjet recording apparatus according to another embodiment of the present invention.

[Explanation of symbols]

2 Recording paper as the recording material 4 Drums 6 Drum drive device 50 Carriage 52 Platen 101 Recording head

Claims (3)

[Claims] 1. In an inkjet recording method for forming a gradation image using a recording head having a plurality of ink ejection orifices, the scanning direction on a recording material and the ink ejection orifice arrangement direction of the recording head are set in a predetermined manner. Recording is performed by relatively moving the recording material and the recording head so that ink droplets are set at an angle and non-parallel to the same pixel from individual ink discharge ports included in the recording head. An inkjet recording method characterized by: 2. In an inkjet recording method that expresses gradation by ejecting a plurality of ink droplets in a predetermined pixel in an overlapping manner, an ejection port array in which N ink ejection ports are arranged substantially in a straight line is used. When arranging a recording head having at least one row to face the recording material, the scanning line and the recording head are arranged so that the ejection port arrays face each other across L scanning lines, and the recording head and the recording material By relatively moving the material, a maximum of M (M=N/L) ink droplets per ejection port array can be ejected from different ink ejection ports that make up the ejection port array within the same pixel. An inkjet recording method characterized by: 3. In claim 1, when the pitch of the scanning lines is A, A×L is 0.5 mm or less, or
An inkjet recording method characterized in that L is set to 8 or less.