JPH09193371A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain uniform excellent image quality responding to requirement of various resolutions and recording speeds by establishing a specified relationship between a Weber number of ink drop and a Reynolds number, in an ink jet recording device. SOLUTION: In an on-demand type ink jet recording device having a plurality of nozzles for discharging ink drops, a relationship to be expressed by an expression III is established between a Weber number We > 0 of ink drop to be expressed by an expression I and a Reynolds number Re > 0 to be expressed by an expression II, wherein ρrepresents density of ink (g/cm<3> ), (d) and (v) respectively represent vacuum conversion diameter (μm) and flying speed (m/s) of ink drop, γ represents surface tension of ink (dyne/cm), and η represents viscosity of ink (cp). In an ink jet head, a plurality of laminated piezoelectric elements are connected and arranged in two rows on a head substrate formed of ceramics and glass epoxy resin. Also, a frame which surrounds the periphery of the laminated piezoelectric elements in each row is connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording apparatus, and more particularly to an on-demand type inkjet recording apparatus having a plurality of nozzles for ejecting ink droplets.

[0002]

2. Description of the Related Art A drop-on-demand (DOD) type ink jet recording apparatus used in printers, facsimiles, copiers, etc., has a plurality of nozzles for ejecting ink droplets, a liquid chamber communicating with the nozzles, and a liquid chamber. An ink jet is provided from a nozzle only when a recording signal is input by using an inkjet head equipped with an electromechanical conversion element such as a piezoelectric element for pressing or an actuator (driving source) including a thermomechanical conversion element such as a thermal resistor. High-speed, high-resolution recording is performed by ejecting droplets.

In such an ink jet recording apparatus, since the liquid ink is directly ejected and adhered to the recording medium (the one to which the ink droplets adhere) for printing, the shape of the ink droplets to be dots and the ink and the recording medium. The compatibility of the will greatly affect the recording quality. In particular, when using plain paper that is commonly used as a recording medium, blurring of dots,
The formation of unnecessary dots due to printing in the state where the number of flying ink drops is 2 or 3 (the unnecessary satellite drops are generated) will significantly deteriorate the image quality.

Therefore, as a conventional ink jet recording apparatus, for example, as described in JP-A-3-211057, the Reynolds number (Re) and the Weber number (We) of the ink drop are obtained in order to obtain a dot close to a perfect circle. So that the product of and is in the range of 100 to 30,000,
As described in Japanese Unexamined Patent Publication No. 4-235042, there is known one in which the ink drop weight, drop speed, drop roundness, and dot spread rate are limited.

[0005]

However, although the above-mentioned conventional ink jet recording apparatus can be expected to improve the image quality to some extent, it is still insufficient for achieving higher resolution and higher image quality. At the same time, there is a problem in that it is impossible to uniformly obtain good image quality with respect to demands of various different resolutions and recording speeds.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an ink jet recording apparatus capable of uniformly obtaining good image quality in response to various demands of various resolutions and recording speeds. To aim.

[0007]

In order to solve the above problems, an ink jet recording apparatus according to a first aspect of the present invention is an on-demand type ink jet recording apparatus having a plurality of nozzles for ejecting ink droplets. ) And the Reynolds number (Re) represented by the equation (2), the relation represented by the equation (3) is established.

[0008]

(Equation 5)

[0009]

(Equation 6)

[0010]

(Equation 7)

An ink jet recording apparatus according to a second aspect is the ink jet recording apparatus according to the first aspect, wherein the relationship represented by the above equation (3) is established between the Weber number (We) and the Reynolds number (Re). At the same time, the configuration represented by the equation (4) is established.

[0012]

(Equation 8)

An ink jet recording apparatus according to a third aspect is the ink jet recording apparatus according to the first or second aspect,
The weight of the ink droplet ejected from one nozzle by one driving pulse signal is 0.1 μg or less, and the ink droplet flying speed is 5 m / s or more.

According to a fourth aspect of the invention, there is provided an ink jet recording apparatus according to any one of the first to third aspects, wherein the number of ink droplets ejected by one drive pulse signal is one droplet per nozzle. did.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view showing an example of an ink jet head of an ink jet recording apparatus to which the present invention is applied, FIG. 2 is an enlarged sectional view of an essential part of the head, and FIG.
FIG. 3 is an enlarged cross-sectional view of a main part of the head in a direction different from that of FIG.

This ink jet head is provided on a head substrate 1 made of ceramic, glass epoxy resin or the like.
A plurality of laminated piezoelectric elements 2 are joined and arranged in two rows, and a frame 3 surrounding the periphery of each laminated piezoelectric element 2 in each row is joined. Here, the plurality of laminated piezoelectric elements 2 include a laminated piezoelectric element 2 (hereinafter, referred to as a “driving portion piezoelectric element” 4) that serves as a driving portion and a laminated piezoelectric element 2 (hereinafter, referred to as a strut portion). This will be referred to as "strut piezoelectric element 5"). In addition, the laminated piezoelectric element 2
The upper surface of the frame 3 and the upper surface of the frame 3 are substantially flush with each other.

A vibration plate 7 is bonded to the upper surfaces of the laminated piezoelectric element 2 and the frame 3. The vibrating plate 7 is formed of a diaphragm 8 serving as a displacement portion, a beam 9 joined to the pillar piezoelectric element 5 and a base 10 joined to the frame 3, and the diaphragm 8 is a convex portion opposed to the driving portion piezoelectric element 4. 11 and the thin film portion 12. The head substrate 1, the laminated piezoelectric element 2, and the vibration plate 7 are bonded to each other with an adhesive 6.

A liquid chamber flow path forming member 13 made of a dry film resist (photosensitive resin film) having a two-layer structure is adhered onto the vibrating plate 7, and a plurality of nozzle holes 14 are formed on the liquid chamber flow path forming member 13. The nozzle plate 15 formed with is bonded. The liquid chamber flow path forming member 13 includes an upper partition wall 17 and a lower partition wall 18, and is located on both sides of the pressurized liquid chamber 19, the pressurized liquid chamber 19 facing the piezoelectric element 4, together with the vibrating plate 7 and the nozzle plate 15. Common liquid chamber 20, pressurized liquid chamber 19 and common liquid chamber 20
The ink supply path 21 which also functions as a fluid resistance portion is formed.

Further, on the head substrate 1, a common electrode pattern 25 that conducts to all the laminated piezoelectric elements 2 and a selection electrode pattern 26 that individually conducts to the driving portion piezoelectric elements 4 are formed. The common electrode pattern 25 is electrically connected to all the laminated piezoelectric elements 2 by a conductive member (not shown) bonded on the base substrate 1 at a position corresponding to the hole 27 formed in the center of the frame 3. There is.
Although the selection electrode pattern 26 is connected to the pillar piezoelectric element 5 in the manufacturing process, the selection signal is not applied.

Further, ink supplied from the outside is supplied to the common liquid chamber 20 in the head substrate 1, the frame 3 and the vibrating plate 7.
Ink supply holes 30, 31, and 32 for supplying the ink are formed respectively.

In this ink jet, a driving pulse is applied through the common electrode pattern 25 and a selection signal corresponding to a recorded image is applied through the selection electrode pattern 26, so that the driving portion piezoelectric element 4 is selectively selected. By driving the ink to pressurize the ink in the pressurized liquid chamber 19 and eject ink droplets from the nozzles 14, an image is recorded.

Next, an example of a head drive circuit for driving such an ink jet head will be described with reference to FIGS. As shown in FIG. 4, the head drive circuit inputs a reference timing pulse to generate a drive voltage having a predetermined drive waveform, and a waveform generation circuit 41 outputs the waveform generation circuit 41 to drive each of the inkjet heads H. A constant voltage drive circuit including a low impedance output circuit 42 for outputting to the piezoelectric elements 4, 4, ... And a channel selection circuit 44 for giving a selection signal to the drive piezoelectric elements 4, 4 ,. .

The waveform generation circuit 41 of the constant voltage drive circuit is
It can be composed of an OM, D / A converter or other pulse generating circuit and a waveform modifying circuit such as a calculus integrating circuit, a clipping circuit, a clamp circuit, or the like. In addition, the low impedance output circuit 42
Is a buffer amplifier, SEPP (Single Ended Pu)
It consists of a low impedance amplifier composed of sh pull, etc. By using the low impedance output circuit, the output of the drive voltage waveform becomes a low impedance output to the piezoelectric element, and the waveform is not distorted due to the variation of the piezoelectric element and the number of drive channels.

On the other hand, the selection circuit 44 includes a shift register circuit, a latch circuit, and a piezoelectric element 4 of each drive unit of the ink jet head H (a channel, where a channel is composed of one nozzle, a pressurized liquid chamber and a piezoelectric element). It is used in the sense of the part) and consists of a transistor and a die-dode array.

Here, a specific example of the constant voltage drive circuit will be described with reference to FIG. This circuit connects an input terminal IN, to which an input signal is applied, to the base of a transistor Tr1 via a buffer B and to the base of a transistor Tr2 via an inverter I, and supplies the power supply voltage Vs to the collectors of these transistors Tr1. However, the emitter of the transistor Tr2 is grounded.

Between the emitter of the transistor Tr1 and the collector of the transistor Tr2 are connected a parallel circuit of a series circuit of a resistor ra and a diode D1 and a series circuit of a resistor rb and a diode D2, and these diodes D1 and D2 are connected.
1 and D2 are connected to a point, a capacitor Ck is connected between the a point and the ground, and a time constant circuit for charging with a resistor ra and a capacitor Ck and a time constant circuit for discharging with a resistor rb and a capacitor Ck. Are configured. Further, the point a connected between the capacitor Ck and the resistors ra and rb is a diode Dk.
Is connected to the power supply voltage Vth via.

Then, point a is the transistor Tr3 to Tr3.
A low-impedance output circuit 42 consisting of 6 is connected between the base of a transistor Tr3 on the input side and the base of a transistor Tr4, and is a transistor Tr on the output side.
Between the emitter of No. 5 and the collector of the transistor Tr6, a plurality of driving parts piezoelectric elements 4, 4 of the inkjet head H are provided.
Is connected to the common terminal COM.

In this constant voltage drive circuit, when a pulsed input signal is input to the input terminal IN (becomes "H"), the buffer B outputs a voltage level lower than the power supply voltage Vs, and the transistor Tr1 is turned on. The transistor I is turned on, and the inverter I turns off the transistor Tr2. Therefore, charging of the capacitor Ck is started with a time constant determined by the resistor ra and the capacitor Ck by the power supply voltage Vs. At this time, since the point a is connected to the power supply voltage Vth via the diode Dk (falling voltage Vd), the charging voltage of the capacitor Ck does not rise to the power supply voltage Vs, but the voltage Vp.
It is clipped to (Vp = Vth + Vd).

When the pulsed input signal is not input to the input terminal IN (becomes "L"), the output of the buffer B becomes the power supply voltage Vs, so that the transistor Tr1 is turned off and the output of the inverter I is output. Becomes "H", the transistor Tr2 is turned on. Therefore, the resistance r
The capacitor Ck is discharged with a time constant determined by b and the capacitor Ck.

Therefore, the low impedance output circuit 4
A drive waveform as shown in FIG. 6 is output from 2 and applied to the drive piezoelectric element 4 selected by the channel selection circuit 44, so that each channel of the inkjet head H is selectively driven.

Therefore, the control of ink drops according to the present invention will be described with reference to FIG. 7 and subsequent figures. First, the above equations (1) and (2) derived from the physical properties of ink (density, viscosity, surface tension) and the ejection characteristics of ink droplets (ink droplet diameter, droplet velocity)
Weber number (We) and Reynolds number (R
Regarding e), as shown in the above formula (3), 8 · Re
-300 ≦ We ≦ 8 · Re + 100 relationship (however, We
> 0 and Re> 0. ), An excellent image can be obtained. The conditions of the ink droplets vary depending on the resolution and the recording speed (printing speed), but the ejection characteristics of the ink droplets that produce a good image under each condition are included in the range represented by the above formula (3).
The evaluation results regarding this point will be described later.

Further, together with the relation expressed by the equation (3),
As shown in the above formula (4), We ≦ −5 · Re + 500
By setting the relationship (however, We> 0) to be established, more stable recording can be performed in consideration of the shape of the ink droplet.

These points will be described in detail. First, the relationship between the ink drop velocity, the ink drop shape, and the dot shape will be described with reference to FIGS. 7 to 10. FIG. 7 shows a change in ink droplet speed (ink droplet flying speed m / s) when a driving condition (for example, driving energy) is changed. In FIG. 7, v1 is the speed of one ink droplet or a plurality of ink droplets. The velocity of the first ink drop when ejecting
Reference numeral 2 indicates the velocity of the last ink droplet when a plurality of ink droplets are being ejected. In addition, A, B, and C in the figure respectively show typical measurement points.

As can be seen from FIG. 7, when the driving conditions are changed and the ink droplet velocity is increased, a plurality of ink droplets are ejected at a certain value (x) as a boundary. That is, as shown in FIG. 8, the number of ink droplets I ejected from the nozzles 14 of the nozzle plate 15 (ink droplet shape) is one droplet at the measurement point A as shown in FIG. At the measurement point B, a plurality of drops are formed as shown in FIG.
Further, at the measurement point C, the number of droplets is large and the number of droplets is large as shown in FIG.

Drive conditions for increasing the drive speed include increasing the power supply voltage Vs or Vth in the constant voltage drive circuit of FIG. 5 to increase the drive waveform Vp or decreasing the resistance ra. This can be obtained by reducing the rise time of the drive waveform (tr in FIG. 6).

Further, as shown in FIG. 9, when the ink drop weight is kept constant and the ink drop velocity is changed to the drop velocities A ', B', and C ', the ink drop shapes are also shown in FIGS. (C)
Same as shown in. That is, the ink drop velocity A '
8A, the ink shape shown in FIG. 8A is obtained, the ink shape shown in FIG. 8B is obtained at the ink drop velocity B ', and the ink drop shape shown in FIG. 8C is obtained at the ink drop velocity C'. . In this way, the shape of the ink drop is greatly influenced by the difference in ink drop velocity.

On the other hand, regarding the shape of the ink drop and the shape of the dot, while the ink jet head having the nozzles for ejecting the ink drop is moved at a constant speed, as shown in FIGS.
The dot shapes when printed with the ink droplet shape shown in are as shown in FIGS. That is, FIG.
The dot shape shown in FIG. 10A is obtained when the ink droplet shape shown in FIG. 8A is obtained, and the dot shape shown in FIG. 10B is obtained when the ink droplet shape shown in FIG. When the ink droplet shape is shown in FIG. 10A, the dot shape shown in FIG. From this, it can be seen that when printing is performed in the state where a plurality of ink droplets are formed, the roundness of dots is significantly reduced.

Therefore, in the present invention, the number of ink droplets ejected by one drive pulse signal is always one. Here, as described above, when the driving condition is changed to change the ink droplet speed, a plurality of ink droplets are formed under a certain driving condition (value of x). Therefore, by controlling the ink physical property value and the head structure. The value of (x) is changed to a higher ink drop velocity so that the number of ink drops ejected by one drive pulse signal is always one.

When the dot shape shown in FIG. 10 (b) is obtained with the ink droplet shape shown in FIG. 8 (b), the moving speed of the ink jet head (the carriage moving speed on which the head is mounted) is increased. As the ink droplet shape shown in FIG. 8B is changed to the dot shape shown in FIG. 10C, the ink droplet ejected by one drive pulse signal is always one droplet. By doing so, high-speed printing can be realized.

Here, if the ink droplet speed is set to a driving condition such that the ink droplet speed is slower than the value (x) shown in FIG. 7, it is possible to always make one ink droplet. If it becomes slower, when ink droplets are ejected from a plurality of nozzles, variations in ink droplet velocity among the nozzles will appear as variations in dot position accuracy. That is, as the ink drop velocity is slower or the carriage movement speed is faster, the ink drop velocity variation becomes more prominent as the dot position accuracy variation.

Therefore, the dot position accuracy can be ensured by making one ink drop ejected by one drive pulse signal and making the ejected ink drop velocity 5 m / s or more. Then, considering the bleeding of dots, the permissible water content of paper, and the higher density of dots, the weight of ink droplets ejected from one nozzle by one drive pulse signal is set to 0.
Make 1 μg.

Furthermore, the ink droplet speed and the ink droplets can be changed depending on whether the ink droplets are ejected at a high driving frequency from a plurality of nozzles at the same time for all printing patterns, for example, the ink droplets are ejected at a low driving frequency from a single nozzle. If the difference in weight is large, the print quality will be adversely affected.

Therefore, when the fluctuation range of the ink drop velocity and the ink drop weight is within 15% of the ink drop ejection characteristic value (drop speed, drop weight) of a single nozzle with respect to the fluctuation of the driving condition, the dots depending on the print pattern. Stable printing characteristics can be obtained by suppressing deterioration of image quality due to changes in diameter and dot position accuracy.

In this regard, FIG. 11 shows the results of evaluation of drive frequency and ink drop weight variation with heads of different dimensions. The broken line in the figure shows the change in the weight of the ink droplet when the width of the ink supply path for supplying ink to the ink liquid chamber is widened to reduce the fluid resistance value, and the solid line shows the change in the width of the ink supply path and the The changes in the ink drop weight when the resistance value is increased are shown.

As can be seen from the figure, the drive frequency is set to 1K.
When the frequency is set to Hz, the ink droplet weight is almost the same regardless of the fluid resistance value. However, when the driving frequency is increased, the ink cannot be smoothly supplied when the fluid resistance value is large, and the ejected ink is ejected. Drop weight is significantly reduced. That is, when compared with the ink drop weight when the drive frequency is 1 KHz, the maximum drop is about 12% when the fluid resistance value is small, but the maximum drop is about 39% when the fluid resistance value is large. When printing was performed using each of these heads, good results were obtained with a head with a small fluid resistance value, but with a head with a large fluid resistance value, the variation in dot diameter due to the drive frequency was marked. It was not suitable for.

Next, a specific example of the present invention will be described with reference to FIG. In the figure, the ink surface tension is 29.6.
10 in the range of (dyne / cm) to 58.2 (dyne / cm)
The Weber number (We) and the Reynolds number (Re) when performing ink droplet ejection evaluation using various types of ink are shown. In the figure, the print dot shape at the points indicated by "○" is as shown in FIG. 10A, and the print dot shape at the points indicated by "△" is as shown in FIG. Therefore, the print dot shape at the points indicated by “x” becomes the dot shape as shown in FIG.
This indicates that the ejected ink droplets are unstable and the ink droplet ejection characteristics are not suitable for printing.

Here, when the dot shape as shown in FIG. 10A, or at least the dot shape as shown in FIG. 10B is obtained, that is, the dot shape at the point indicated by ◯ or Δ in FIG. Number of Webers (We)
And the Reynolds number (Re) are generalized, the relationship represented by the above equation (3) holds between the Weber number (We) and the Reynolds number (Re), and the above equation (3) It was found that the dot shape becomes better when the relationship shown in 4) holds.

Therefore, different physical properties and ink ejection characteristics of the ink are selected so that the relationship represented by the equation (3) is established between the Weber number (We) and the Reynolds number (Re). It is possible to obtain an appropriate image quality that meets each condition for various specifications. Then, by further satisfying the relationship represented by the equation (4), stable ink ejection characteristics can be obtained, so that an image with excellent reproducibility can be obtained.

Table 1 shows the relationship between the ink droplet speed and the number of ink droplets ejected by one driving pulse signal when the ink droplet ejection evaluation is performed with inks having different physical property values. This result shows that the physical property value of the ink is the surface tension of 29.8 (d
yne / cm) and a viscosity of 1.40 (cp) and an ink having a surface tension of 35.9 (dyne / cm) and a viscosity of 3.35 (cp), respectively, and an ink drop velocity of 4 ~ 11m /
It shows the number of ink drops when changed in the range of s.

[0050]

[Table 1]

The obtained dot shape and dot position were analyzed. As for the inks shown in Table 1, when the ink drop velocity was 8 to 9 m / s and there was only one ink drop, the dot shape and dot position were determined. Good results were obtained in terms of accuracy. Also, depending on the moving speed of the carriage,
For each of the inks, a good image was obtained when the ink drop velocity was 5 m / s or more and the number of ink drops was one.

In the above embodiments, an ink jet head using a piezoelectric element as an actuator has been described, but the present invention is also applicable to an ink jet head using a heater element as an actuator. However, the use of the piezoelectric element for the actuator has an advantage that the ink droplets can be easily controlled.

[0053]

As described above, according to the ink jet recording apparatus of the first aspect, the Weber number (We) represented by the equation (1) and the Reynolds number represented by the equation (2) ( Re), the relationship represented by the equation (3) is established, so that good image quality that meets each condition can be obtained for various specifications with different resolutions and recording speeds. .

According to the ink jet recording apparatus of the second aspect, in the ink jet recording apparatus of the first aspect,
Since the relationship represented by the equation (3) is established between the Weber number (We) and the Reynolds number (Re), and the relation represented by the equation (4) is established,
Stable ink ejection characteristics can be obtained, and an image with excellent reproducibility can be obtained.

According to the ink jet recording apparatus of the third aspect, in the ink jet recording apparatus of the first or second aspect, the weight of the ink droplet ejected from one nozzle by one driving pulse signal is 0.1 μg or less. Moreover, since the ink droplet flying speed is set to 5 m / s or more, it is possible to form uniform dots having excellent dot position accuracy, and it is possible to obtain a higher quality image.

According to the ink jet recording apparatus of the fourth aspect, in the ink jet recording apparatus according to any one of the first to third aspects, the number of ink droplets ejected by one drive pulse signal is one droplet per nozzle. As a result, the deterioration of the image quality due to unnecessary satellite droplets is reduced, the roundness of the dots is improved, and a clearer image can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of an inkjet head to which the present invention is applied.

FIG. 2 is an enlarged sectional view of a main part of the head.

FIG. 3 is an enlarged cross-sectional view of a main part of the head in a direction different from that of FIG.

FIG. 4 is a block diagram of a head drive circuit.

FIG. 5 is a specific circuit diagram of a constant voltage drive circuit of a head drive circuit.

FIG. 6 is a waveform diagram of drive waveforms output from the identification voltage drive circuit.

FIG. 7 is an explanatory diagram illustrating a relationship between a driving condition and an ink drop velocity.

FIG. 8 is an explanatory diagram illustrating the relationship between ink drop velocity and ink drop shape.

FIG. 9 is an explanatory diagram illustrating the relationship between ink drop weight and ink drop velocity.

FIG. 10 is an explanatory diagram illustrating the relationship between ink drop velocity and dot shape.

FIG. 11 is a diagram illustrating the relationship between the drive frequency and the ink drop weight for different fluid resistance values.

FIG. 12: Weber number (We) and Reynolds number (R
e) An explanatory view for explaining the relationship with

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Multilayer piezoelectric element, 3 ... Frame, 4 ... Drive part piezoelectric element, 5 ... Support part piezoelectric element, 7 ... Vibrating plate, 13
... liquid chamber flow path forming member, 14 ... nozzle, 15 ... nozzle plate,
17 ... Upper partition wall, 18 ... Lower partition wall, 41 ... Waveform generating circuit, 42 ... Low impedance output circuit.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hideyuki Makita 1-3-3 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Yoshihisa Ota 1-3-3 Nakamagome, Ota-ku, Tokyo Shares Company Ricoh

Claims (4)

[Claims] 1. An on-demand type ink jet recording apparatus having a plurality of nozzles for ejecting ink droplets,
Weber number (We) represented by the equation (1) of the ink drop
And the Reynolds number (Re) shown in equation (2),
An inkjet recording apparatus characterized in that the relationship represented by (3) is established. [Equation 1] [Equation 2] (Equation 3) 2. The ink jet recording apparatus according to claim 1, wherein the Weber number (We) and the Reynolds number (R)
The inkjet recording apparatus is characterized in that the relationship expressed by the formula (3) and the relationship expressed by the formula (4) are satisfied with respect to e). (Equation 4) 3. The ink jet recording apparatus according to claim 1, wherein the weight of the ink droplet ejected from one nozzle by one driving pulse signal is 0.1 μg or less, and the ink droplet flying speed is An ink jet recording apparatus having a speed of 5 m / s or more. 4. The ink jet recording apparatus according to claim 1, wherein the number of ink droplets ejected by one drive pulse signal is one per nozzle. .