JPH03224745A - Inkjet head drive system and recording device - Google Patents

Abstract

PURPOSE:To make it possible to change stable recording density by enabling selection between a power-ON ejection mode and a power-OFF ejection mode for a head drive process in a single head and thereby controlling the diameter of ink droplets. CONSTITUTION:If the turn-ON ejection mode is used for the drive of an ink jet head, an oscillation plate 2 is deformed in a direction where a liquid chamber 5 contracts by application of a voltage to a piezoelectric element 1 when a liquid chamber 5 has expanded with the piezoelectric element 1 remaining undriven. Subsequently, ink is ejected from a nozzle 4. Next, if a turn-OFF ejection mode is employed, ink is supplied to the liquid chamber 5 following its expansion by gradually lowering a voltage from a state where a voltage is applied during printing process. However, in this mode, the liquid chamber 5 remains contracted due to the application of a voltage to the piezoelectric chamber 1 during non-printing process. When the piezoelectric element 1 is energized in the following step of operation by a drive signal, the liquid chamber 5 contracts to allow ink to be ejected from the nozzle 4. Subsequently, an intermediate tone can be obtained by selecting between the turn-ON ejection mode and the turn-OFF ejection mode using an external input signal and thereby changing the diameter of ink dots.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet head drive system and a recording device, and more particularly to an inkjet recording device applied to inkjet printers, plotters, facsimile machines, copiers, and the like.

In the past, in methods using piezoelectric elements and bubble jet methods using heating elements, the diameter of ink droplets was controlled by changing the pulse width or driving voltage. Also,
When expressing halftones using conventional technology, the ink dot diameter is controlled by changing the pulse width or the drive voltage as described above to express halftones, and the ink deposition density is The midtones were expressed by changing the .

However, although it is possible to digitally change the pulse width, it has not been possible to significantly change the ink droplet diameter. In addition, to change the drive voltage, it is necessary to do it in an analog manner, which not only tends to complicate the drive circuit, but also causes the following problems. , is a diagram showing the relationship between the drive voltage of the inkjet head, the mass of the ink droplet, and the velocity of the ink droplet. Figure 1 (a) is a diagram of the relationship between the drive voltage of the inkjet head and the mass of the ink droplet, and Figure (b) is the diagram showing the relationship between the drive voltage of the inkjet head and the mass of the inkdrop. FIG. 3 is a relationship diagram between voltage and ink droplet velocity. As is clear from the above relationship diagram, both the ink droplet mass and the ink droplet velocity increase in proportion to the drive voltage of the inkjet head. Therefore, if the driving voltage is lowered to reduce the mass of the ink droplet, the velocity of the ink droplet will also be reduced.

On the other hand, in a serial (continuous) scanning type inkjet recording device, the inkjet head moves at a constant speed in the main scanning direction while ejecting ink. This changes the position of the inkjet head in response to changes in the active voltage of the inkjet head, which affects the dot position accuracy.

When the main scanning speed is constant, the greater the absolute value of the ink droplet velocity, the smaller the width of variation in dot position accuracy. In other words, it is desirable that the ink droplet velocity be high because a large tolerance for variations can be achieved.

As mentioned above, the conventional method of lowering the drive voltage of the inkjet head in order to reduce the mass of the ink droplets reduces the speed of the ink droplets, which reduces the tolerance for variation in the speed of the ink droplets, which causes problems in recording gradation. Ta.

The present invention was made in view of the above-mentioned circumstances, and
The first purpose is to switch the drive method of the inkjet head to either a push method or a pull method to eject ink, and the difference in jetting characteristics when ejecting ink between the push method and the pull method. Focusing on the fact that there are differences in ink droplet diameter due to By taking advantage of the difference in ink droplet ejection characteristics caused by driving a push or pull type inkjet head, it is possible to significantly change the recording dot density (for example, 300 dpi (300 dpi) with the same inkjet head.
A recording device that can stably perform dots/inch) and 600 dpi). Specifically, even if the mass of ink droplets is changed significantly, the fluctuation range of ink droplet speed, that is, the tolerance can be large, and it is practically stable. The purpose of this invention is to provide an inkjet recording device that makes it possible to change a certain recording density, thereby providing an inkjet recording device that can provide image output that meets a wide range of needs with a single recording device.

(2) In order to achieve the first object mentioned above, the present invention provides (1) a drop-on-demand type inkjet head active system using piezoelectric elements, in which the head driving system is changed to a pressing system within the same head; (2) Drop diameter control based on halftone data in a drop-on-demand inkjet head drive system using piezoelectric elements. A signal is generated, and by the control signal, it is possible to select whether the head opening method is a push method or a pull method to eject ink, and the ink droplet diameter can be changed to obtain intermediate tones. or to achieve the second purpose above.

(3) By switching the drop-on-demand inkjet head drive method using piezoelectric elements to a push or pull method within the same head,
In a recording device in which the recording dot density can be selected by changing the ink droplet diameter, recording with a small recording dot density is performed by a push-dot method, and recording with a large recording dot density is performed by a pull-dot method, and further, (4) In (3) above, the selectable recording dot density is P dots/inch and 2
In an inkjet recording device with a recording dot density of P dots/inch, the nozzle array in a multi-nozzle head having a plurality of nozzles is formed so as to achieve a recording dot density of P dots/inch per one main scan. When the dot density is selected to be P dots/inch, the printing method is switched to the push-punching method, and a recording width corresponding to the number of nozzles is achieved at a recording dot density of P dots/inch by one scan at a main scanning speed corresponding to the jetting frequency. If the recording dot density is selected to be 2P dots/inch, the recording method is switched to the pulling method and recording is performed in one scan at the main scanning speed corresponding to the ejection frequency selected in the pulling method. , after the recording, the recording paper is moved in the sub-scanning direction by a length equivalent to one dot pinch, and recording is performed again at the main scanning speed with a recording width corresponding to the number of nozzles, and (5) in (4) above, In an inkjet recording device that mixes and records an image with a recording dot density of P dots/inch and an image with a recording dot/inch of 2P dots/inch on the same recording paper, it is possible to print an image with a recording dot density of either P dots/inch or 2P dots/inch. After recording is completed, the recording paper is fed backward by a required length and recording is performed at another recording dot density. below.

An explanation will be given based on an example of the present invention.

FIGS. 1(a) to 1(c) are explanatory diagrams of the operation of the pressing method of the inkjet head driving method according to the invention as set forth in claims 1 and 2 of the present invention for achieving the first object. In the figure, 1 is a piezoelectric element, 2 is a vibration plate, 3 is a head substrate, 4 is a nozzle, and 5 is a liquid chamber.

(a) shows the liquid chamber 5 in a state where the piezoelectric element 1 is not driven.
is in an expanded state, and in this state, when a voltage as shown in FIG. 3(a) is applied to the piezoelectric element 1, the diaphragm 2 becomes (
As shown in b), the liquid chamber 5 is deformed in the direction of contraction, and ink is ejected from the nozzle 4. Next, the voltage is shown in Figure 3 (
When the piezoelectric cord 1 slowly falls as shown in a), the piezoelectric cord 1 returns to its original state as shown in (c). At this time, new ink is supplied into the liquid chamber 5 to prepare for the first printing.

FIGS. 2(a) to 2(c) are explanatory diagrams of the operation of the pulling method of the inkjet head driving method according to the present invention.
The same reference numbers as in FIG. 1 are provided. In this pulling method, a voltage is applied to the piezoelectric element 1 during non-printing, contrary to the pushing method.

(b) By keeping the liquid chamber 5 in the contracted state as shown in (a), and then slowly lowering the voltage from the applied state as shown in FIG. 3 (b) when printing next time.
As shown in (c), the liquid chamber 5 expands and ink is supplied into the liquid chamber 5, and as shown in (c), at the next rise of the drive signal, the liquid chamber 5 contracts and ink is ejected from the nozzle 4.

In the present invention, intermediate tones can be produced by switching between the above-mentioned push printing method and pull printing method using an external input signal and changing the ink dot diameter.

FIG. 5 shows an example of the drive circuit, FIG. 6 is a time chart in FIG. 5, and FIG. 4 is an example of printing when the above-described time chart is used.
FIG. 6 is a diagram showing pixels each having a small dot diameter. In FIG. 5, the 3gl terminal is a print signal, and the 8g2 terminal is a drive system switching signal, which are generated and sent from a processing circuit (not shown).

CLK is a basic timing signal, 1o is a bistaple flip-flop, 11 is a monostable flip-flop for determining the width of the drive signal applied to the piezoelectric element, 13.17.18 is an AND circuit, and 14.15 is an AND circuit. The NANDAND circuit is an OR circuit, 19, 20, and 21 are buffer circuits, and 22 is a piezoelectric element. Ql, Q2 are p
Q3 is an npn type output transistor.

R2 and R3 are for controlling the rise and fall times of the piezoelectric cable rotation signal, and R1 is for protecting Q3, and is selected to have a lower resistance value than R2 and R3. R2
, R3 are values determined from the capacitance of the piezoelectric element and the rise and fall times.

The circuit operation will be explained below.

Now, when printing dots with large pixel diameters of il and i2 shown in Fig. 4 (by pressing method), Q
When I is turned ON and Q3 is turned OFF, Q is applied to the piezoelectric element.
A current flows through the route L and R1, and the piezoelectric element is displaced. That is, at this time, ink is ejected from the nozzle. Next, Ql is OFF.

When Q3 turns ON, the electric charge charged in the piezoelectric element becomes R3.
, Q3 route. At this time, if the R3 value is large, the battery will discharge slowly. This is to prevent air from being drawn into the liquid chamber from the nozzle.

Next, in order to print i4 by the pull printing method, it is first necessary to displace the liquid chamber as shown in FIG. 2(a) when the drive method switching signal is received.

Therefore, Q2 is applied to the piezoelectric element through ONL and R2 (which has a large resistance value like R3 and slowly displaces the piezoelectric element). At the actual printing timing, Q2 is first turned OFF and Ql is turned ON.

After slowly discharging the liquid chamber and returning the liquid chamber to the state shown in FIG. 2(b), Q3 is turned OFF and Ql is turned ON, thereby contracting the liquid chamber and ejecting ink from the nozzle.

Next, to switch from the pulling method to the pushing method, turn off Ql and Q2, and turn on Q3, and the charge stored in the piezoelectric element will be slowly discharged through R3 and Q3, as shown in Figure 1. The shape of the liquid chamber returns to the steady state of the push method as shown in (a), and is ready for printing using the push method.

As described above, the output transistors Ql, Q2.S3 are created from each input signal, and the output transistors Ql, Q2. By controlling Q3, it is possible to print characters of different sizes as shown in FIG.

Furthermore, the invention described in claims 3 to 5 will be explained below.

FIG. 7 is a configuration diagram of a suitable inkjet recording apparatus for achieving the second purpose, in which 31 is a nozzle, 32
3 is a flow path plate, 33 is a flow path, 34 is a fluid resistance, 35 is a common liquid chamber, 36 is an external electrode, 37 is a drive circuit printed circuit board, 3
8 is a piezoelectric element, 39 is a substrate, 40 is an N-holding plate, 41 is an ink droplet, and 42 is an ink liquid inlet. A piezoelectric element 38 made of PZT (lead zirconate titanate) or the like is bonded to the substrate 39 with a protection plate 40 in contact with the end surface, and the piezoelectric element 38 is connected to an electric circuit (not shown) on a drive circuit printed circuit board (PCB) 37. ) and is electrically controlled via external electrodes 36 to displace in the thickness direction (vertical direction in the drawing). This displacement has the function of reducing or expanding the volume of the flow path (pressurized liquid chamber) 33 provided in the flow path plate 32. The flow path (pressurized liquid chamber) 33 communicates with the common liquid chamber 35, and since the common liquid chamber 35 is filled with ink supplied from the ink liquid inlet 42, the flow path (pressurized liquid chamber) The ink in the chamber 33 is ejected as ink droplets 41 from the nozzle 31 when the chamber is contracted, and when the chamber is expanded, the ink is supplied from the common liquid chamber 35 into the channel 33.

The details of the method of controlling ink jetting in the inkjet head and the relationship between the ink droplet mass (m, ) and the ink jetting speed (V,) will be described below.

The above-mentioned ink ejection control method includes a first control method (hereinafter referred to as a push method, but the push method is also referred to as a push [dynamic]) and a second control method (hereinafter referred to as a pull method). , the pulling method is also called the pullH motion).

FIG. 8 is a diagram showing the pulse waveform of the driving voltage pulse in the push-and-strike method, in which (a) shows the pressurizing and jetting process in one cycle, and (b) shows the ink filling process in one cycle. , (c) shows the residual vibration damping step during one cycle. The piezoelectric element (PZT) 38 is configured to reduce the volume of the flow path (pressurized liquid chamber) 33 when a positive voltage is applied. In the push method, in the pressurization/injection process of (a), the piezoelectric element (PZT) 38 is displaced so as to reduce the volume of the flow path (pressurized liquid chamber) 33, so the ink 'a41 is applied from the nozzle 31. In the ink filling process of (b), the displacement of the piezoelectric element (PZT) 38 returns to the initial position, and the volume of the flow path (pressurized liquid chamber) 33 is also restored.
The flow path (pressurized liquid chamber) 33 is filled with ink. In reality, the response of the fluid is accompanied by a delay. In the residual vibration damping step (c), the flow path (pressurized liquid chamber) 33, piezoelectric element (PZT)
Fluid resistance 3 due to 38 components and ink viscosity, etc.
This process includes vibration damping determined by 4.

FIG. 9 is a diagram showing the pulse waveform of the drive voltage pulse in the pulling method, and (a) in the figure.

(c) is the pressurization/jetting and residual vibration damping process in one cycle, and (b) is the ink filling process in one cycle. In the pulling method, a constant positive voltage is applied in advance to the piezoelectric element (PZT) 38 to open the flow path (pressurized liquid chamber) 33.
The piezoelectric element (PZT) 38 is displaced inwardly within the flow path, and when an image signal is received, the applied voltage is reduced to zero level as shown in step (b), and the piezoelectric element (PZT) 38 moves toward the flow path ( Ink is filled by displacing the pressurized liquid chamber (pressurized liquid chamber) 33 in the expansion direction, and then, in step (a), a positive voltage is applied to the piezoelectric element (PZT) 38 to reduce the flow path (pressurized chamber) 33. to displace the piezoelectric element (PZT) 38,
This pressurizes and jets the ink.

Next, let's examine the relationship (a) when the same inkjet head is used to drive the push printing method and the pull printing method.

Figures 10(a) and 10(b) are diagrams showing the relationship between the driving voltage (v) and the ink ejection speed (v,) in the push-in method; It is a figure obtained from voltage results.

Figures 11 (a) and (b) show the ink ejection velocity (V,) and ink droplet mass (m,) J in the pulling method.
Figure (a) shows the relationship between driving voltage (V) and ink ejection speed (V,), and Figure (b) shows the relationship between driving voltage (V) and ink droplet mass (m,). Show the relationship of P
This is a diagram of J.

From the push method of FIG. 10 and the pull method of FIG.
Comparing the ink droplet velocity (V,) when obtaining an ink droplet mass (m, ) of 10-9 grams, it is approximately 3 m/s (29 seconds) for the push method and approximately 3 m/s (29 seconds) for the pull method. The ink droplet velocity (V, ) of the pull-type method is approximately 8 m/s (two-9 seconds), and the ink droplet velocity (V, ) of the pull-type method is more than twice that of the push-type method (V,).
is obtained.

Next, an example of achieving recording dot densities of 300 dpi (dots/inch) and 600 dpi using the above inkjet head will be described.

Figure 12 is a diagram showing an example of the relationship between the ink droplet mass (m,) and the dot diameter (d,) on the recording paper, and shows the experimental results when Gilbird bond (25% cotton) paper was used as the recording paper. It is. Note that the above relationship differs somewhat depending on the type of recording paper.

Usually, the dot diameter (
An appropriate dimension for d and ) is approximately the width of f of the dot pitch. Therefore, the appropriate size for the dot diameter is approximately 120 pm (microns) at 300 dpi and 600 d
pi is approximately 60 μm (microns).

Therefore, from Figure 12, the appropriate ink droplet mass (m,) is approximately 120 x 10-g grams at 300 dpi 600 dp
i is about 40 x 10-9 grams.

As a way to achieve these, Assuming that 300 dpi is used in the push-and-push method shown in Figure 10.

The driving voltage is about 27V, and the ink droplet speed at that time is about 5m/
s (meter 7 seconds). When 600 dpi is set to the pull-dot method shown in Fig. 11, the driving voltage is approximately 23 V and the ink droplet velocity is approximately 5 m/s. By changing the control method and driving voltage, the recording dot density can be set to 300 dpi, 60 dpi, or 60 dpi.
Ink droplet velocity (v,) for both 0 dpi and 5 m/s
It can be done.

Regarding the inkjet driving method of the present invention described above, when recording dot densities of 300 dpi and 600 dpi are performed only by driving by the push method, the ink droplet speed is approximately 2 m/s when the ink droplet mass is 40 x 10-' grams.
As a result, the tolerance for variations in ink droplet velocity (V,) between nozzles or with changes in image frequency becomes extremely small, making it difficult to stably obtain images with good dot position accuracy.

In addition, in the case of only the active pulling method, it is difficult to increase the mass of ink droplets (m,), and the configuration of the inkjet head used in the embodiment of the present invention is suitable for ink droplets suitable for a recording dot density of 300 dpi. A droplet mass (m,) of 120×10−′ grams was not obtained within the predetermined drive voltage range.

From the above, the same inkjet head has 300dpi, 6
As a method to achieve 00 dpi, the recording dot density is 30 dpi.
For 0dpi, push drive, recording dot density 60
It can be seen that for 0 dpi, the method using the pull printing method is very effective.

Next, a specific method of outputting images with recording dot densities of 300 dpi and 600 dpi using the above inkjet head will be described.

FIG. 13 is an explanatory diagram for showing the relationship between the arrangement of inkjet heads and images with recording dot densities of 300 dpi and 600 dpi. Figure CQ) shows a 600 dpi dot array.

The nozzles are arranged at a pitch that forms an image equivalent to a recording dot density of 300 dpi in one scan, and to obtain an image with a recording dot density of 600 dpi, the hatched dots shown in Figure (c) are printed in the first scan. Then, after feeding the recording paper 1 dot pitch or 1/600 inch,
A 600 dpi image can be formed by printing the dots in the blank areas in Figure (a) in the second scan. By repeating the scanning described above, part of the recording is completed.

The above description is based on the case where the pixel density is constant over the entire page, but the recording method allows the recording dot density to be 300.
As a method of mixing a dpi image and a 600 dpi image on the same page, for example, a recording dot density of 300 dp
After printing the i-image, the recording paper is moved in the opposite direction to the desired position, and an image with a recording dot density of 600 dpi is recorded again. For example, when inserting a high-precision diagram or image into a text, the text has a recording dot density of 30.
High-speed output at 0 dpi and image recording dot density of 600 d
Pi makes it possible to output with high accuracy.

Other merits of the above recording device include the following. The recording device has a page memory (approximately IME for A4) with a recording dot density of 300 dpi.
When printing with pi, it is used as a full page memory, and when printing with a recording dot density of 600 dpi, the same memory is used as 1
/Can handle screen sizes up to 4 pages. When inserting an image into a normal text, a screen size of 1/4 page is often sufficient, so it is possible to provide a practical recording device with low memory cost. In particular, in the case of color recording, the memory cost is usually four times that of monochrome (single color), so the economic effect is large.

FIG. 14 is a block diagram showing an example of the circuit configuration of the inkjet recording apparatus of the present invention. In the figure, 43 is a host computer, 44 is a controller, 45 is a driver, and 45
Reference numeral a denotes a driver with a recording dot density of 300 dpi using a push printing method, 45b a driver with a recording dot density of 600 dpi using a pull printing method, 46 an inkjet head, and 47 a scanning system. Based on the image information input to the host computer 43, the host computer 43 discriminates between, for example, the recording dot density of 300 dpi and 600 dpi, determines whether to use the push method or the pull method, and based on the determined command signal. to drive the controller 44. For example, in the case of character information, a driver 45a using a push method with a recording dot density of 300 dpi is selected from among the drivers 45.
is selected, the inkjet head 46 is driven to print, and the scanning system 47 is driven according to the recording speed at this time.

Similarly, for image information, the recording dot density is 600 dpi.
The inkjet head 46 is driven by selecting the driver 45b using the pulling method, and the scanning system 47 performs a setting movement such as moving one dot pitch in the sub-scanning direction, thereby printing different recording dot densities according to the image information. Print and create some images.

Effects --- As is clear from the above explanation, the present invention has the following effects.

(1) By switching the driving method within the same inkjet head, such as a pull-printing method or a push-printing method, the print dot diameter can be changed, and halftones can be expressed with a simple configuration. Furthermore, by using this method in combination with the conventional method, it becomes possible to express a wider range of intermediate tones.

(2) By switching the drive method of the same inkjet head to the push-dot method for recording with a low recording dot density and to the pull-dot method for recording with a high recording dot density, the mass of ink droplets can be changed significantly.

It is possible to provide a recording device that has a large tolerance for ink droplet velocity fluctuations and is stable and has excellent coordination even when the recording dot density is changed significantly. Furthermore, this allows one device to obtain image output that meets a wide range of needs.

[Brief explanation of drawings]

FIGS. 1(a) to (C) are operation explanatory diagrams of the push method of the inkjet head drive method according to the present invention, and FIG.
a) to (c) are explanatory diagrams of the operation of the pulling method of the inkjet head driving method according to the present invention, and FIGS.
b) is a diagram showing the applied voltage waveform, (a) is for the push printing method, (b) is for the pull printing method, FIG. 4 is a diagram showing an example of printing, and FIG. 5 is a diagram of one of the drive circuits. 6 is a time chart thereof, FIG. 7 is a diagram showing the structure of an inkjet head implementing another inkjet head driving method and inkjet recording apparatus according to the present invention, and FIG. 8 is a diagram showing a push The figure which shows the pulse waveform of the drive voltage pulse in a striking method. FIG. 9 is a diagram showing the pulse waveform of the driving voltage pulse in the pulling method, FIGS. ) is the relationship between drive voltage and ink ejection speed,
(b) is a diagram showing the relationship between driving voltage and ink droplet mass;
Figure 11(a). (b) is a diagram showing the relationship between ink ejection speed and ink droplet mass in the pulling method, and (,) is a diagram showing the relationship between driving voltage and ink jetting speed. (b) is a diagram showing the relationship between driving voltage and ink droplet mass. Figure 12 is a diagram showing an example of the relationship between ink droplet mass and dot diameter on recording paper, and Figure 13 is a diagram showing an example of the relationship between ink droplet mass and dot diameter on recording paper.
An explanatory diagram for showing the relationship between i and a 600 dpi image,
FIG. 14 is a block diagram showing an example of the circuit configuration of the inkjet recording apparatus of the present invention, and FIG. 15(a). (b) is a diagram showing the relationship between the drive voltage of the inkjet head, the ink droplet mass, and the ink droplet speed, and Figure (a)
2 is a diagram showing the relationship between the driving voltage of the inkjet head and the mass of the ink droplet, and FIG. 1. 38...Piezoelectric element, 2゜2...Vibration plate, 3゜39...Head board, 4゜31...Nozzle, 5゜5...Liquid chamber.

Claims (1)

[Claims] 1. In a drop-on-demand inkjet head drive method using a piezoelectric element, the head drive method can be selectively switched to a push method or a pull method within the same head, and the ink droplet diameter can be changed. An inkjet head drive system that is characterized by being controllable. 2. In the Dolla on-demand inkjet head drive system that uses piezoelectric elements, halftone images can be obtained by switching between the push and pull methods during one main scanning period of printing and controlling the diameter of the ink droplets. The inkjet head drive method is characterized by: 3. A recording device that makes it possible to select the recording dot density by changing the ink droplet diameter by switching the drop-on-demand inkjet head drive method using piezoelectric elements to a push or pull method within the same head. An inkjet recording apparatus characterized in that recording with a low recording dot density is performed by a push-dot method, and recording with a high recording dot density is performed by a pull-dot method. 4. In the inkjet recording device in which the selectable recording dot densities are P dots/inch and 2P dots/inch, the nozzle arrangement in a multi-nozzle head having a plurality of nozzles is determined by the recording dot density per one main scan. If the recording dot density is selected to achieve P dots/inch, switch to the push printing method and print P dots in one scan at the main scanning speed corresponding to the jetting frequency. If the recording dot density is set to 2P dots/inch, the recording width corresponding to the number of nozzles is recorded with a recording dot density of Records in one scan at the corresponding main scanning speed,
4. The inkjet recording apparatus according to claim 3, wherein after the recording, the recording paper is moved in the sub-scanning direction by a length equivalent to one dot pitch, and recording is performed again at the main scanning speed with a recording width corresponding to the number of nozzles. 5. In an inkjet recording device that mixes and records an image with a recording dot density of P dots/inch and an image with a recording dot/inch of 2P dots/inch on the same recording paper, the recording dot density P
After recording either dots/inch or 2P dots/inch, the recording paper is fed backwards by the required length,
5. The inkjet recording apparatus according to claim 4, wherein recording is performed at a different recording dot density.