JP2002254625A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording device capable of performing a high speed and a high density recording without being affected by environmental temperature. SOLUTION: A drive waveform for separating one ejected ink drop into plural ink drops during its flying is applied to a head 40, and a parameter of the drive waveform is corrected based on a detection result of the environmental temperature by a thermo-sensor 90 to correct printing intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus.

[0002]

2. Description of the Related Art An ink jet recording apparatus used as an image recording apparatus (image forming apparatus) such as a printer, a facsimile, a copying apparatus, and a plotter includes a nozzle for discharging ink droplets and an ink flow path (discharge chamber, The ink jet head includes a pressure chamber, a pressurized liquid chamber, and a liquid chamber.) And a driving unit that pressurizes the ink in the ink flow path.

[0003] In an ink jet head, as a means for generating energy for pressurizing ink in an ink flow path, a diaphragm forming a wall surface of the ink flow path is deformed by using a piezoelectric element, thereby forming a volume in the ink flow path. Or a so-called piezo type in which ink droplets are ejected by changing the pressure (see Japanese Patent Application Laid-Open No. 2-51734), or a pressure generated by heating ink in an ink flow path using a heating resistor to generate bubbles. A so-called bubble type (see Japanese Patent Application Laid-Open No. 61-59911), in which a diaphragm and an electrode forming a wall surface of an ink flow path are arranged to face each other, and generated between the diaphragm and the electrode. An electrostatic type in which the diaphragm is deformed by the applied electrostatic force to change the volume in the ink flow path and eject ink droplets (Japanese Patent Laid-Open No.
-71882) and the like.

Since high-speed and high-quality recording is required in an ink jet recording apparatus, a head having an increased number of nozzles for ejecting ink droplets is disclosed in Japanese Patent Application Laid-Open No. 9-57966. And those in which the driving frequency of the head is increased as described in JP-A-9-254381 are known.

[0005]

However, in the above-mentioned conventional ink jet recording apparatus equipped with a head having an increased number of nozzles, high-speed printing is possible by increasing the number of nozzles. Although,
Increasing the number of nozzles increases the size of the head, complicates the configuration, increases the clogging of the nozzles with ink, and reduces the manufacturing yield.

In particular, in the head described in the above-mentioned publication,
Since ink is ejected by forming a plurality of nozzles in one pressure generating unit, the head configuration becomes extremely complicated and the manufacturing process becomes more complicated.

In general, when the number of nozzles is increased, the number of nozzles is increased in the nozzle row direction, so that the printing speed in the sub-scanning direction is improved, but the printing speed in the main scanning direction is increased. No improvement can be expected. that is,
As the printing density is increased by increasing the number of nozzles and the nozzle density, the problem becomes more prominent, causing a problem that the printing speed in the main scanning direction is further reduced.

On the other hand, in an ink jet head,
In general, after one drop of ink is ejected for one print signal, unnecessary vibration of the ink droplet is ejected by rapidly attenuating the residual vibration of the ink generated in the ink flow path (ejection chamber). Is prevented, high-speed ejection of ink droplets (high-frequency driving) is enabled, and high-speed printing can be performed.

However, in the above-described conventional ink jet recording apparatus in which the driving frequency of the head is increased, in order to rapidly attenuate the residual vibration of the ink generated in the ink discharge chamber, the driving means for the head is extremely difficult. In addition, it is necessary to apply a complicated drive signal waveform, and the configuration of a drive circuit that generates such a drive waveform also has a problem that it is complicated and costly.

Further, in the recording apparatus described in the above-mentioned publication, after applying a driving voltage for ink ejection, it is necessary to wait until the pressure in the ink ejection chamber becomes a positive pressure, and then suppress the residual vibration of the ink. Since the auxiliary voltage is applied again, the time width of the drive voltage required to eject one drop of ink becomes relatively long, making it difficult to print at a higher repetition drive frequency. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording apparatus capable of obtaining stable ink droplet ejection characteristics with a simple configuration and capable of high-speed, high-density recording. I do.

[0012]

In order to solve the above-mentioned problems, an ink jet recording apparatus according to the present invention comprises a plurality of ink droplets ejected from a nozzle to a head driving means while flying. And a correction unit for correcting the printing interval of the plurality of ink droplets on the printing target recording medium based on the ambient temperature of the head.

Here, it is preferable that the driving waveform is a waveform for ejecting ink droplets at an ejection speed at which one ink droplet ejected from the nozzle is separated into a plurality of ink droplets during flight. In this case, the voltage value of the drive waveform is set to a value that results in an ejection speed at which one ink droplet ejected from the nozzle separates into a plurality of ink droplets during flight, or the voltage application time of the drive waveform It is preferable to set a value at which the ejection speed is such that one ink droplet ejected from the nozzle is separated into a plurality of ink droplets during flight.

The correction means can correct the moving speed of the head in the main scanning direction.

In this case, it is preferable that the correction means corrects the frequency of the drive signal for moving the head. Here, it is preferable that the correction means lower the frequency of the drive signal when the ambient temperature increases, and increase the frequency of the drive signal when the ambient temperature decreases. In this case, it is preferable that the correction unit matches the highest frequency value of the drive signal with a frequency value equal to the reciprocal of a time difference between the plurality of ink droplets that changes according to the ambient temperature.

Further, the correction means can correct a time difference between the plurality of ink droplets until the plurality of ink droplets land.

In this case, the correction means can correct the voltage fall time width of the drive waveform. Here, it is preferable that the correction unit increases the voltage fall time width of the drive waveform when the ambient temperature increases, and shortens the voltage fall time width of the drive waveform when the ambient temperature decreases.

The correction means can correct the voltage application time width of the drive waveform. Here, it is preferable that the correction unit shortens the voltage application time width of the drive waveform when the ambient temperature increases, and increases the voltage application time width of the drive waveform when the ambient temperature decreases.

Further, the correction means can correct the applied voltage value of the driving waveform. Here, it is preferable that the correction unit lowers the applied voltage value of the drive waveform when the ambient temperature increases, and increases the applied voltage value of the drive waveform when the ambient temperature decreases.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic perspective explanatory view of a mechanism of an ink jet recording apparatus according to the present invention, and FIG. 2 is a side explanatory view of the mechanism.

This ink jet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 1, a recording head including an ink jet head mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. The paper feed cassette 4 or the manual feed tray 5 takes in the paper 3, and records the required image by the print mechanism 2, and then the output tray mounted on the rear side. 6 is discharged.

The printing mechanism 2 slides the carriage 13 in a main scanning direction (a direction perpendicular to the paper of FIG. 2) by a main guide rod 11 and a sub guide rod 12 which are guide members which are laterally mounted on left and right side plates (not shown). This carriage 1
3 is provided with a head 14 composed of an ink jet head for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) with the ink droplet discharge direction facing downward. Above 13, each ink tank (ink cartridge) 15 for supplying each color ink to the head 14 is exchangeably mounted.

The ink cartridge 15 has an upper air port communicating with the atmosphere, a lower supply port for supplying ink to the inkjet head 14, and a porous body filled with ink inside. The ink supplied to the inkjet head 14 by the capillary force of the body is maintained at a slight negative pressure. The ink is supplied from the ink cartridge 15 into the head 14.

Here, the carriage 13 is slidably fitted to the main guide rod 11 on the rear side (downstream side in the paper transport direction), and is slidably fitted on the front side (upstream side in the paper transport direction).
2 slidably mounted. The main scanning motor 1 is moved to scan the carriage 13 in the main scanning direction.
7, a timing belt 20 is stretched between a driving pulley 18 and a driven pulley 19, which are driven to rotate, and the timing belt 20 is fixed to the carriage 13. When the main scanning motor 17 rotates forward and backward, the carriage 13 is rotated. It is driven back and forth.

Although the head 14 of each color is used here as a recording head, a single head having a nozzle for ejecting ink droplets of each color may be used. Furthermore, head 1
As described later, as described later, an electrostatic type that includes a diaphragm forming at least a part of a wall surface of an ink flow path and an electrode facing the diaphragm and deforms and displaces the diaphragm by electrostatic force to pressurize ink. An inkjet head is used. However,
The present invention is not limited to this. A so-called piezo type in which a diaphragm forming the wall of the ink flow path is deformed by using a piezoelectric element to change the volume in the ink flow path and eject ink droplets, or a heating resistor It is also possible to use a so-called bubble type in which ink droplets are ejected with a pressure generated by heating ink in an ink flow path using a body to generate bubbles.

On the other hand, the sheet 3 set in the sheet cassette 4
Roller 21 and a friction pad 22 for separating and feeding the paper 3 from the paper feed cassette 4 and a guide member 23 for guiding the paper 3
A transport roller 24 that reverses and transports the fed paper 3, a transport roller 25 that is pressed against the peripheral surface of the transport roller 24, and a tip roller 26 that defines an angle at which the paper 3 is fed from the transport roller 24. Is provided. The transport roller 24 is driven to rotate by a sub-scanning motor 27 via a gear train.

An image receiving member 29 is provided as a paper guide member for guiding the paper 3 fed from the transport roller 24 below the recording head 14 in accordance with the moving range of the carriage 13 in the main scanning direction. I have. On the downstream side of the printing receiving member 29 in the sheet conveying direction, a conveying roller 31 and a spur 32, which are driven to rotate in order to send out the sheet 3 in the sheet discharging direction.
And a paper discharge roller 33 and a spur 34 for feeding the paper 3 to the paper discharge tray 6 and guide members 35 and 36 for forming a paper discharge path.

At the time of recording, the recording head 14 is driven in accordance with an image signal while moving the carriage 13 so that ink is ejected onto the stopped paper 3 to record one line, and the paper 3 is moved by a predetermined amount. After transport, the next line is recorded. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 3 has reached the recording area, the recording operation is terminated and the sheet 3 is discharged.

At a position outside the recording area on the right end side of the carriage 13 in the moving direction, a recovery device 37 for recovering the ejection failure of the head 14 is arranged. Recovery device 3
7 has a cap means, a suction means and a cleaning means. The carriage 13 is moved to the recovery device 37 side during the printing standby, the head 14 is capped by the capping means, and the ejection opening (nozzle hole) is kept in a wet state, thereby preventing ejection failure due to ink drying.
Further, by ejecting (purging) ink that is not related to printing during printing or the like, the ink viscosity of all the ejection ports is made constant, and stable ejection performance is maintained.

When a discharge failure occurs, the discharge port (nozzle) of the head 14 is sealed by a capping means, bubbles and the like are sucked out of the discharge port by a suction means through a tube, and ink adhering to the discharge port surface is sucked. The dust and the like are removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) provided at a lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.

Next, an ink jet head constituting the recording head 14 of the ink jet recording apparatus will be described with reference to FIGS. 3 is an explanatory cross-sectional view of the inkjet head in the longitudinal direction of the diaphragm, and FIG. 4 is an enlarged cross-sectional view of a main part of the head in the lateral direction of the diaphragm.

This ink jet head includes a first substrate 41 which is a diaphragm / liquid chamber substrate, a second substrate 42 which is an electrode substrate provided below the first substrate 41, and a first substrate 41.
And a third substrate 43 which is a lid member provided on the upper side of the nozzle groove 44, and a plurality of nozzle grooves 44 for discharging a plurality of ink droplets.
A pressurized chamber (also referred to as a discharge chamber) 46 is an ink flow path communicating with each other, and a common liquid chamber flow path 48 communicates with each pressurized chamber 46 via a fluid resistance part 47 also serving as an ink supply path. are doing.

As the first substrate 41, a single-crystal silicon substrate is used, a nozzle groove 44 is formed at one end, and a pressure chamber 46 communicating with the nozzle groove 44 and a bottom portion which is a wall surface of the pressure chamber 46 are formed. , A groove forming the fluid resistance portion 47, and a recess forming the common liquid chamber flow path 48.

The use of a single-crystal silicon substrate as the first substrate 41 facilitates the processing when the thin diaphragm 50 having a thickness of about several μm is formed by etching, and has a small size of about several μm. The gap can be formed with high accuracy by anodic bonding with the second substrate 42. Further, when the diaphragm 50 is vibrated, it is necessary to apply a voltage to the electrode to generate an electrostatic force. However, since silicon is semiconductive, the diaphragm 50 can also serve as an electrode. Therefore, there is an advantage that there is no need to provide a separate electrode on the diaphragm 50 side.

A recess 54 is formed in the second substrate 42 by using Pyrex (registered trademark) glass (borosilicate glass). The electrode 55 is formed by, for example, sputtering gold or the like, and an actuator section is constituted by the diaphragm 50 and the electrode 55. Note that the electrode 55 extends outside to integrally form an electrode terminal portion 55a. Further, the use of Pyrex glass for the second substrate 42 facilitates anodic bonding with the silicon substrate.

On the surface of the electrode 55, a dielectric insulating layer (oxide-based insulating film) such as a SiO ₂ film or a nitride-based insulating film such as a Si ₃ N ₄ film is used to improve the durability of the electrode 55. Although the electrode protection film 57 is formed, the electrode protection film 57 is not formed on the surface of the electrode 55, or the electrode protection film 57 is formed on the surface of the electrode 55 and the insulating film is formed on the diaphragm 50 side. Can also.

As the third substrate 43, a stainless steel substrate is used, and the third substrate 43 is bonded to the first substrate 41 with an adhesive. The joining of the third substrate 43 forms a nozzle groove 44, a discharge chamber 46, a fluid resistance part 47, and a common liquid chamber flow path 48. Also,
An ink supply port 61 for supplying ink from outside to the common liquid chamber flow path 48 is formed in the third substrate 43, and the ink cartridge 15 described above is connected via an ink supply pipe 62 connected to the ink supply port 61. Supplies ink.

Next, a method of joining the first substrate 41 and the second substrate 42 will be described. A small gap of about several μm is formed with high precision like an electrostatic inkjet head,
As a method of assembling (joining), it is preferable to use an anodic bonding method. This anodic bonding method can be expected to ensure the dimensional accuracy of the gap more than other bonding methods (brazing, fusion welding, etc.), and a voltage is applied between the first substrate 41 and the second substrate 42 (− By applying about 300 V to -500 V), precise bonding can be performed at a relatively low temperature (300 to 400 ° C.).

In order to reliably perform such anodic bonding, the first substrate 41 or the second substrate 42 is so formed that covalent bonding between the substrates occurs at the bonding interface between the first substrate 41 and the second substrate 42. Either must be a substrate that contains a large amount of alkali ions, and when anodic bonding, a material whose coefficient of thermal expansion is relatively consistent between substrates so that distortion between the substrates due to thermal stress is reduced. It is preferable to select.

In this embodiment, as described above, a single-crystal silicon substrate is used for the first substrate 41, and the second substrate 42 contains a large amount of alkali ions such as Na, and has a coefficient of thermal expansion relatively equal to that of the silicon substrate. Since a Pyrex glass (borosilicate glass) substrate is used, reliable bonding with little thermal distortion between the substrates can be obtained.

Next, an outline of a control section of the ink jet recording apparatus will be described with reference to FIG. The control unit includes a microcomputer (hereinafter, referred to as a “CPU”) 80 for controlling the entire recording apparatus, a ROM 81 storing required fixed information, a RAM 82 used as a working memory, and the like. An image memory 83 for storing data obtained by processing the transferred image data;
A parallel input / output (PIO) port 84, an input buffer 85, a parallel input / output (PIO) port 86, a waveform generation circuit 87, a head drive circuit 88, and a driver 8
9, a temperature sensor 90 for detecting the ambient temperature of the head 14 and the like.

Here, the PIO port 84 detects various information such as image data from the host side, various instruction information from an operation panel (not shown), a detection signal of the ambient temperature from the temperature sensor 90, and the start and end of the sheet. A detection signal from a paper presence sensor, signals from various sensors such as a home position sensor for detecting the home position (reference position) of the carriage 13 and the like are input.
Required information is transmitted to the host and the operation panel via the.

The waveform generating circuit 87 generates a driving waveform between the vibration plate 50 and the electrode 55 of the head 14 such that the vibration plate 50 is displaced toward the electrode 55 with a displacement amount enough to eject ink droplets and at a timing. appear. By using a D / A converter for D / A converting the drive waveform data from the CPU 80 as the waveform generation circuit 87, a required drive waveform can be generated and output with a simple configuration. The change of the waveform parameter of the drive waveform based on the ambient temperature,
A table of a plurality of drive waveforms corresponding to the ambient temperature is stored in the OM 81 in advance, and a table of the drive waveform corresponding to the detected ambient temperature based on the detection signal from the temperature sensor 90 is selected and read out, and this is read out by the waveform generation circuit. 87.

The head drive circuit 88 includes a PIO port 86
The driving waveform is applied to the energy generating means (diaphragm 50 and electrode 55) corresponding to each nozzle groove 44 of the head 14 based on various data and signals given via the. Further, the driver 89 controls the driving of the main scanning motor 17 and the sub-scanning motor 27 according to the driving data supplied via the PIO port 86, thereby moving the carriage 13 (recording head 14) in the main scanning direction. And
The transport roller 24 is rotated to transport the sheet 3 by a predetermined amount.

Next, a part related to the head drive control unit in the control unit will be described with reference to the block diagram of FIG. The head drive control unit is provided with the CPU 8 described above.
0, a main control unit 91 including a ROM 81, a RAM 82, peripheral circuits, and the like, a waveform generation circuit 87, an amplifier 92, a drive circuit (driver IC) 93, and the like.

The main control section 91 supplies data for generating a drive waveform to be applied to the electrode 55 of the head to the waveform generation circuit 87, and print signals (serial data) SD, shift signals to the driver IC 93. Clock CL
K, a latch signal LAT, and the like. Waveform generation circuit 87
As described above, a drive waveform that generates energy for ejecting ink droplets from the nozzles 44 to the actuator section of the inkjet head is generated in time series. That is, the main control unit 91 and the waveform generation circuit 87 generate and output a drive waveform, and correct the parameters of the drive waveform (voltage application time width, applied voltage value, or voltage multi-value reduction time width) based on the ambient temperature. Sometimes, these constitute a correcting means.

The driver IC 93 is a control means for selecting a drive waveform input in a time series in accordance with a print signal and controlling the selection of the drive waveform applied to each individual electrode 55 of the ink jet head constituting the head 14. That is, the driver IC 9
Reference numeral 3 denotes a shift register 95 for inputting a serial clock CLK and a serial signal SD as a print signal from the main control unit 91, and a latch circuit 96 for latching a register value of the shift register 95 with a latch signal LAT from the main control unit 91. A level conversion circuit 97 for changing the level of the output value of the latch circuit 96;
And an analog switch array 98 whose turning-off is controlled. The analog switch array 98 includes analog switches AS1 to ASm connected to m individual electrodes 55 of the inkjet head 40 (the number of nozzles is m). The diaphragm 50 serving as a common electrode of the ink jet head is grounded.

Then, the serial data (print signal) SD is taken into the shift register 95 in accordance with the shift clock, and the latch circuit 96 latches the serial data SD taken into the shift register circuit 95 by the latch signal LAT, and the level conversion circuit Enter 98. The level conversion circuit 98 controls the analog switch A connected to the individual electrode 55 of each actuator according to the content of the data.
Sm (m = 1 to m) is turned on / off.

This analog switch ASm (m = 1 to
m) is supplied with a drive waveform from the waveform generation circuit 87 via the amplifier 92, so that the analog switch ASm (m = m)
1 to m) are turned on, the drive waveform is selectively applied to the individual electrodes 55.

Next, the operation of the ink jet head will be described with reference to FIGS. When a positive pulse voltage is applied to the electrode 55 from the head drive circuit 88, the surface of the electrode 55 is charged to a positive potential, and the lower surface of the diaphragm 50 facing the electrode 55 is charged to a negative potential. I do. Therefore, as shown by the arrow in FIG. 7A, the diaphragm 50 is caused to act on the electrode 55 facing the diaphragm 50 by an electrostatic attraction function (electrostatic attraction force).
Deflection in the direction. Here, the magnitude of the electrostatic attraction force P generated on the diaphragm 50 is expressed as in equation (1).

[0051]

(Equation 1)

In the equation (1), ε is the permittivity of the air existing between the diaphragm 50 and the electrode 55, S is the effective area of the electrostatic force acting between the diaphragm 50 and the electrode 55,
V indicates a drive voltage value applied to the electrode 55, and d indicates an effective gap distance between the diaphragm 50 and the electrode 55.

Here, the effective gap distance d is expressed by equation (2) when a substance having a dielectric constant other than air is interposed between the diaphragm 50 and the electrode portion 55.

[0054]

(Equation 2)

[0055] However, in the equation (2), a dielectric insulating layer between the d _a diaphragm 50 and the distance of the gap existing between the electrodes 55, the d _epsilon diaphragm 50 and the electrode portion 55 5
The thickness of 7 and ε _r indicate the relative permittivity of the dielectric insulating layer 57.

That is, when a substance having a certain dielectric constant is interposed between the diaphragm 50 and the electrode 55, as shown in the equation (2), the thickness d _{ε of the} interposed dielectric substance and the dielectric substance By changing the relative permittivity ε _r of
Electric field intensity E (E (E) generated between diaphragm 50 and electrode 55
= V / d), and the magnitude of the electrostatic attraction force PP generated thereby changes.

Therefore, as shown in the equation (1), the magnitude of the electrostatic attraction force PP is such that the smaller the effective gap distance d between the diaphragm 50 and the electrode 55, the greater the electrostatic attractive force to the diaphragm 50. Works. Further, as the drive voltage value V to the electrode 55 increases, the diaphragm 50 bends toward the electrode 55,
As shown in FIGS. 3B and 3C, the diaphragm 50 is
5 contacts with the dielectric insulating layer 57. The state where the diaphragm 50 is in contact with the electrode 55 in this manner is referred to as a contact state.

When the application of the pulse voltage, which is a pulse-like voltage, to the electrode 55 is turned off, the waveforms shown in FIGS.
As shown in FIG. 7, since the restoring force PP1 is acting on the flexed (deformed) diaphragm 50, the diaphragm 50 exerts the restoring force PP.
1 and the pressure in the pressurizing chamber 46 rapidly rises, so that ink droplets 65 are formed from the nozzle grooves 44 and the paper 3
The ink droplet 65 is ejected toward. When a pulse voltage is applied (ON) to the electrode 55, the diaphragm 50 bends again in the direction toward the electrode portion 55, so that the ink flows into the common liquid chamber flow path 4.
8, the pressure is supplied into the pressurizing chamber 46 through the fluid resistance portion 47.

Next, the separation and formation of ink droplets in the ink jet recording apparatus having the above configuration will be described with reference to FIGS. First, a method of forming a plurality of small droplets by discharging one ink droplet with one print signal will be described with reference to FIG. According to the present invention, when a drive signal is applied to one drive means of the head corresponding to one print signal, one ink droplet I is ejected from the nozzle 44 as shown in FIG. Is discharged. This one ink droplet D0 is separated into two ink droplets D1 and D2 during flight as shown in FIG. 3B, and has desired ejection speeds V1 and V2 as shown in FIG. Two ink drops D1,
Focusing on the phenomenon flying as D2, this phenomenon is utilized.

That is, as schematically shown in FIG. 9C, a plurality of ink droplets formed when one ink droplet is separated have substantially the same droplet volume. ), A plurality of ink droplets are formed while maintaining a predetermined time interval Td corresponding to the print density (25.4 × 10 −3 / δ [dpi]) on the paper 3 as the print target medium. When the ink droplet lands on the paper 3, as shown in FIG. 3E, printing is performed with a plurality of printing pixels D 1 ′ and D 2 ′ at a time for one printing signal using the plurality of ink droplets. It is possible to do.

Further, since printing is performed with a plurality of small ink droplets separated from one large ink droplet, it is possible to simultaneously perform printing with smaller print pixels.
The phenomenon in which a single ink droplet is separated to obtain a plurality of ink droplets of substantially the same volume depends on the ejection speed and viscosity of the ink droplet, but is remarkable by reducing the volume of the ink droplet to about 10 pl or less. Will appear in

Next, FIG. 10 shows, as shown in FIG. 11, the driving waveforms of the applied voltage value Vp, the voltage application time width Tp,
.. Are applied to the head in the repetitive printing cycle T, and the carriage 13 (shuttle) on which the head is mounted is moved in the main scanning direction to form the plurality of separated ink droplets on the paper 3. FIG. 7 is an explanatory diagram illustrating an ink droplet landing state when printing is performed by landing.

Here, in general, the printing speed of the ink jet recording apparatus increases as the moving speed VSH of the carriage 13 increases, and the carriage moving speed (carriage speed) VSH [m / s] Maximum printing cycle Tmax [s] when drop is repeatedly ejected
(That is, the maximum drive frequency Fmax [Hz] of the head and the print density of the image on the print-receiving medium (25.4 × 10−3 / δ)
[Dpi]). The relationship between these and the carriage speed VSH is expressed by the following equation (3).

[0064]

(Equation 3)

That is, in order to increase the carriage speed VSH, the maximum print cycle Tmax of the drive waveform applied to the head is shortened (the maximum drive frequency Fmax is increased), or the print density of the image is reduced to increase the print interval δ. There is only. Therefore, when an attempt is made to obtain a high-quality image by further increasing the print density of the image, the printing interval δ becomes smaller, so that the shuttle moving speed (carriage speed) VSH becomes inevitably slower, and the ink jet recording apparatus becomes This will cause the printing speed to slow down.

Therefore, even in an image having a high printing density,
In order to obtain a constant printing speed so that the printing speed does not decrease, it is necessary to further increase the maximum driving frequency Fmax of the driving waveform applied to the head. Since the ejection state of the droplet becomes unstable, the magnitude of the driving frequency applied to the head is also limited.

Here, the shuttle moving speed VSH and the image printing density (25.4 × 1) expressed by the above equation (3) are used.
0-3 / δ [dpi]), a graph of FIG.
It becomes as shown in. From the figure, for example, an image having a printing density of 600 dpi is converted to a maximum driving frequency of 10 kHz (f
When printing in 1), set the shuttle speed to about 42
It is possible to print at a speed of 3 mm / s (V600), but if it is intended to obtain a 1200 dpi image with a higher print density at the same maximum drive frequency f1 (= 10 kHz), the shuttle Travel speed is about 212
It can be seen that the printing speed is reduced to a speed of mm / s (V1200) and the printing speed is reduced.

When the moving speed VSH of the shuttle is constant (V
In order to keep the maximum driving frequency f1 at 600 kHz, it is necessary to discharge ink droplets from the head at a frequency 20 kHz (f2), which is twice the maximum driving frequency f1, but at such a high frequency, the ink droplet discharge state becomes unstable. In the worst case, ink droplets may not be ejected.

However, according to the printing method of the present invention, for example, two ink droplets are formed separately from one ink droplet, and each ink droplet is subjected to printing while maintaining a predetermined time interval corresponding to the printing density. Since the ink is landed on the medium, the highest drive frequency is kept at 10 kHz (f1), that is, while the shuttle moving speed is maintained at a high speed of (V600), a high-quality image corresponding to 1200 dpi of higher printing density is obtained. It is possible to obtain.

The number of ink droplets formed separately is not limited to two. The number of ink droplets formed separately is increased, and a predetermined number of ink droplets are formed between each ink droplet in accordance with the printing density. If it is possible to keep the time interval, it is possible to form a plurality of ink droplets separately, thereby increasing the speed of movement of the shuttle.

The means for separating and forming ink droplets will now be described. When only the magnitude of the applied voltage Vp is changed while keeping the voltage application time width Tp of the driving waveform shown in FIG. 11 constant, the ejection speed V0 of the ink droplet D0 or the ejection speed V1 of the ink droplet D1 in FIG. FIG. 13 shows the relationship with the ejection speed V2 of the ink droplet D2.

As shown in the figure, the ink droplet D0 has a tendency that the ejection speed V0 also increases as the applied voltage value Vp increases, and the ejection speed V0 is increased by 4 m by increasing the applied voltage value Vp. / S, the separation of the ink droplet D0 is started, and as shown in FIG. 9C, the two ink droplets D1 and D2 fly at the respective ejection speeds V1 and V2. I understood.

Therefore, in the embodiment of the present invention, by adjusting the magnitude (applied voltage value) Vp of the applied voltage of the drive waveform to adjust the ejection speed V0 of the ink droplet D0 to 4 m / s or more, one ink can be obtained. A plurality of ink droplets can be formed separately from the ink droplet, and two separated ink droplets D can be formed.
By adjusting the ejection speeds V1 and V2 of D1 and D2 with the magnitude of the applied voltage Vp of the drive waveform, the time interval between each ink droplet can be adjusted according to the printing density (printing interval) of an arbitrary image. Adjustment can be performed flexibly.

Further, with the applied voltage value Vp in the driving waveform shown in FIG.
FIG. 14 shows the relationship between the ejection speed V0 of the ink droplet D0, the ejection speed V1 of the ink droplet D1, and the ejection speed V2 of the ink droplet D2 in FIG.

As shown in the figure, the ejection speed V0 of the ink droplet D0 tends to increase or decrease as the voltage application time width Tp increases. However, as in the case where the applied voltage value Vp is changed, when the ejection speed V0 exceeds 4 m / s, separation of the ink droplet D0 is started, and FIG.
As shown in the figure, the voltage application time width T during which two ink droplets D1 and D2 fly at their respective ejection speeds.
It was found that a region of p was present.

Therefore, in another embodiment of the present invention, similarly to adjusting the magnitude (applied voltage value) Vp of the applied voltage of the drive waveform, the voltage drop time width Tp of the drive waveform is adjusted to adjust the ink drop. By adjusting the ejection speed V0 of D0 to 4 m / s or more, it becomes possible to separate and form a plurality of ink droplets from one ink droplet, and to eject each of the two separately formed ink droplets D1 and D2. By adjusting the speeds V1 and V2 with the voltage application time Tp of the drive waveform, it is possible to flexibly adjust the time interval between each ink droplet according to the printing density (printing interval) of an arbitrary image. .

Further, by adjusting the voltage application time Tp of the drive waveform, each ink droplet ejected from a plurality of nozzles can be made to fly as a single droplet or formed separately into a plurality of ink droplets.

More specifically, FIG. 15A, FIG. 15B, and FIG. 15C show a plurality of nozzles (here, nozzles a, b, and c) arranged in the nozzle row direction (sub-scanning direction). As shown, for the nozzle a, the voltage application time Tp = Ta
The drive pulse Pa of (Ta in FIG. 14) is applied to the nozzle b, and the drive pulse Pb of the voltage application time Tp = Ta (Ta in FIG. 14) is applied to the nozzle c.
b (Tb in FIG. 14), the drive pulse Pc
It is assumed that a and Pc are applied at the same timing, and the drive pulse Pb is applied at a timing delayed by time Td with respect to the drive pulse Pa.

In this case, as shown in FIG. 7D, the ink droplet D0 from the nozzle a is not separated but is separated into one ink droplet D0.
The ink droplet D0 from the nozzle b is landed at a position corresponding to the print density, and the ink droplet D0 from the nozzle b is not separated as shown in FIG. The ink droplets D0 are separated from the nozzle c to form two ink droplets D1 and D2, and a plurality of print pixels are printed at a time, as shown in FIG. As described above, by adjusting the voltage application time width Tp of the drive waveform, it is also possible to selectively use the printing operation for each nozzle while maintaining a constant printing speed.

Next, the relationship with the viscosity of ink when a plurality of ink droplets are separately formed from one ink droplet will be described. Voltage application time width Tp in the drive waveform of FIG.
When only the applied voltage value Vp is changed while keeping the ink constant, the ink viscosities η1 (= 2 mPa · s) and η2 (= 3 mPa · s)
s) and η3 (= 4 mPa · s).
FIG. 16 shows the relationship between the ejection speed V0 of the ink droplet D0, the ejection speed V1 of the ink droplet D1, and the ejection speed V2 of the ink droplet D2.

As can be seen from the figure, the viscosity η of the ink droplet
In the case of 1, η2, the ejection speeds V0, V1, and V2 of the ink droplets are different even at the same applied voltage Vp, but as shown in FIG. When the speed V0 exceeds 4 m / s, the separation of the ink droplet D0 starts, and as shown in FIG. 9C, the two ink droplets of the ink droplet D1 and the ink droplet D2 form the respective ejection speeds V1 and V2. The same phenomenon of flying with appears.

On the other hand, when the viscosity of the ink droplet is η3, the separation of the ink droplet D0 does not start even if the maximum driving voltage is applied to the head. That is, there is a region where the ink droplet D0 cannot be separated as the viscosity of the ink droplet increases.

Therefore, in the embodiment of the present invention, a plurality of ink droplets are separated from one ink droplet with a lower applied voltage by adjusting the viscosity η of the ink to a low viscosity of about 3 mPa · s or less. .

The application of the present invention to the ink jet recording apparatus according to the present embodiment having the above-described ink jet head will be described. First, when a drive pulse having an applied voltage value V1 as shown in FIG. 17A is applied to the electrode 55 of the inkjet head 40, the applied voltage value V1
The meniscus in the nozzle groove 44 serving as a non-ejection nozzle (meaning a nozzle that does not eject an ink droplet) at each time point t0 to t7 of the drive pulse vibrates as shown in FIG. Further, while the diaphragm 50 and the electrode 55 are in contact with each other (while the diaphragm 50 is in contact with the electrode 55), the current value is positive or negative as shown in FIG. It is observed that a charge / discharge current in the form of oscillating flows. Further, the pressure in the pressurizing chamber 46 is observed to fluctuate in the positive and negative directions as shown in FIG.

As described above, when the driving pulse having the applied voltage value V1 is applied to the electrode 55, the vibration phenomenon occurs in the meniscus, the diaphragm-electrode current (charge / discharge current), and the pressure in the pressurizing chamber. As described in FIG. 7 and FIG.
At the same time as the vibration plate 50 is bent toward the electrode 55 to be in the contact state, the nozzle groove 44 side and the fluid resistance portion 47 are inserted into the pressurizing chamber 46.
Experiments have shown that this is because ink flows in from the sides, and a strong pressure wave is generated in the pressurizing chamber 46 when the diaphragm 50 is in contact with the flow of each ink.

Further, the pulse width (voltage application time) of the pulse-like voltage is set at times t1 to t7 with reference to time t0 in FIG.
When it is changed to the above, the discharge characteristic value of the ink droplet (the discharge speed Vj of the ink droplet and the discharge amount = drop volume Mj) changes as shown in FIG. That is, pulse width (voltage application time)
It has been confirmed by experiments that the discharge characteristic value of the ink droplet fluctuates to a large or small value by changing.

Here, it was experimentally confirmed that the oscillation cycle of the ink droplet ejection characteristic value corresponds to the oscillation cycle of the pressure fluctuation in the pressurizing chamber 46. That is, as seen from the pressure fluctuation waveform in the pressurized chamber shown in FIG.
From 0 to t1, the inside of the pressurizing chamber 46 is in a negative pressure state. In this case, as shown in FIG.
1 is canceled by the negative pressure PP2 generated in the pressurizing chamber 46, and acts in the direction in which the ink flow velocity in the direction of the nozzle groove 44 decreases, so that the negative pressure PP2 is in a stronger time region (time t0). In the period from t1 to t1, a state occurs in which ink droplets are not ejected.

Since the diaphragm 50 is in the contact state at the time point t1, the positive current generated at the time of the contact at the time point ta flows as shown in the charge / discharge current waveform shown in FIG. In addition, since the pressure fluctuation value (negative pressure PP2) becomes zero, ink droplet ejection is started. Further, at time t
From 1 to t3, the pressure chamber 46 is in a positive pressure state. In this case, as shown in FIG.
1 occurs when the positive pressure PP3 generated in the pressurizing chamber 46 is superimposed, and the ink flow speed in the direction of the nozzle groove 44 increases.

Therefore, in this ink jet head, after the diaphragm 50 is in the contact state (after the contact).
The discharge characteristic value (discharge speed, discharge amount) of the ink droplet fluctuates in accordance with the magnitude of the positive and negative pressure fluctuations generated in the pressurizing chamber 46, and the positive pressure P3 in the pressurizing chamber 46 peaks ( The discharge characteristic value of the ink droplet reaches a peak (maximum) corresponding to the time points t2 and t6 when the maximum pressure reaches the maximum pressure, and the negative pressure PP in the pressurizing chamber 46.
At the time point t4 when 2 reaches a peak (minimum), a characteristic appears in which the ejection characteristic value of the ink droplet has a peak (minimum).

Therefore, by utilizing the characteristic that the discharge speed of the ink droplet fluctuates in accordance with the magnitude of the positive and negative pressure fluctuations generated in the pressurizing chamber 46, the discharge speed of the ink droplet is 4 m / m. By applying a drive waveform having a voltage application time width (pulse width) exceeding s, two ink droplets can be caused to fly at respective ejection speeds as shown in FIG. 9C.

Next, correction based on the ambient temperature of the head when a plurality of ink droplets are formed from one ink droplet as described above will be described. In the above description, it is assumed that the moving speed VSH of the shuttle and the time interval (printing cycle) Td at which the plurality of ink droplets land on the printing medium (paper) are predetermined constant values, and there is no fluctuation due to disturbance.

However, actually, depending on the surrounding environment in which the ink jet recording apparatus is used, the moving speed VSH of the shuttle and the time interval (print cycle) Td at which a plurality of ink droplets land on the printing medium fluctuate. The position of the landing of the ink droplet on the print-receiving medium deviates from a predetermined position (predetermined printing interval) δ, and the arrangement of print pixels is disturbed, thereby deteriorating the image quality.

In particular, in the case of an ink jet recording apparatus, since the ink liquid is used, the viscosity η of the ink liquid greatly fluctuates according to the change in the ambient temperature Tmp of the head (printing element) as shown in FIG. . In the example of FIG.
When the head ambient temperature changes from 10 ° C to 40 ° C,
The viscosity of the ink liquid is about 3 (η1) to 1.5 (η2) [mPa
[S] shows an example in which the viscosity changes almost twice as much up to the value of [s].

FIG. 22 shows how the ejection speeds V1 and V2 of a plurality of (two) ink droplets change with respect to the change in the viscosity of the ink liquid as shown in FIG. For example, when the ambient temperature of the printing element becomes a high temperature (A) of about 40 ° C., as shown in FIG.
When the same constant drive voltage waveform is applied to the head, the respective ejection speeds Vj of the plurality of ink droplets become higher as shown in FIG. as a result,
The time interval (printing cycle) Td between the plurality of ink droplets fluctuates in a longer direction, and the printing interval δ on the print-receiving medium becomes wider than the predetermined interval, and printing is performed.

Conversely, when the ambient temperature of the head becomes a low temperature (B) of about 10 ° C., the viscosity of the ink liquid increases from η0 to η1 as shown in FIG. When the driving voltage waveform is applied to the printing element,
As shown in the figure, the ejection speed of each of the plurality of ink droplets becomes lower. As a result, the time interval (printing cycle) Td between the plurality of ink droplets fluctuates in a direction to be shorter, and the printing interval δ on the printing medium is narrower than the predetermined interval, and printing is performed.

Therefore, even when the ambient temperature of the head changes, it is necessary to correct (adjust) the printing interval δ between the plurality of ink droplets on the printing medium to a predetermined value.

Here, when the plurality of ink droplets are landed on the printing medium, the printing interval δ between the respective ink droplets, the moving speed VSH of the shuttle, and the plurality of ink droplets land on the printing medium. The relationship with the time interval (printing cycle) Td is expressed by the following equation (4).

[0098]

(Equation 4)

That is, in order to adjust the printing interval δ of the plurality of ink droplets on the printing medium to a predetermined value, the shuttle moving speed VSH or the plurality of ink droplets is transferred onto the printing medium. By adjusting either the landing time interval (printing cycle) Td or one of them, the printing interval δ by a plurality of ink droplets can be effectively corrected to a predetermined value.

Therefore, in the present invention, first, the carriage 13
The printing speed δ is corrected by adjusting the moving speed VSH of the shuttle, which is the moving speed (carriage speed) of the shuttle. That is, as shown in FIG. 22, the ambient temperature of the head changes to change the viscosity of the ink liquid, and the print cycle Td between the plurality of ink liquids is changed from a predetermined print cycle Td0 to a short print cycle Td1 or a long print cycle Td2. 23, the relationship between the printing interval δ by a plurality of ink droplets and the shuttle movement speed VSH is as shown in FIG.

For example, when the head ambient temperature Tmp decreases and the viscosity of the ink liquid increases, the printing cycle Td between a plurality of ink droplets fluctuates toward the printing cycle Td1 shorter than the initial predetermined printing cycle Td0. I do. At this time, the shuttle movement speed VSH is equal to the initial predetermined movement speed VSH.
If it remains 0, the printing interval by a plurality of ink droplets becomes narrower (changes from δ0 (point a) to δ1 (point c)). As a result, the printing density on the print-receiving medium 3 is increased, and although an image with a relatively high print density can be obtained, image blurring or character collapse occurs, and an appropriate image cannot be obtained. There is a risk.

Conversely, when the head peripheral temperature Tmp rises and the viscosity of the ink liquid decreases, the printing cycle Td between a plurality of ink droplets is longer than the initial predetermined printing cycle Td0. Fluctuates to At this time, the shuttle moving speed VSH is equal to the initial predetermined moving speed VSH.
If SH0 remains, the printing interval by a plurality of ink droplets becomes narrower (changes from δ0 (point a) to δ2 (point b)). As a result, the print density on the print-receiving medium 3 may be reduced, resulting in an image having a relatively low print density.

Therefore, in order to maintain the above-mentioned predetermined printing interval δ0 and obtain an appropriate image, the printing cycle Td between a plurality of ink droplets is shortened due to a change in the viscosity of the ink liquid.
When it becomes 1, the shuttle moving speed VSH is adjusted to the moving speed VSH1 higher than the initial moving speed VSH0 as shown in FIG. 23, and the printing cycle Td between a plurality of ink droplets is longer. When the print cycle Td2 is reached, the shuttle speed V is set as shown in FIG.
By correcting the SH to the moving speed VSH2 lower than the initial moving speed VSH0, the initial proper printing interval δ0
Can be printed.

Such a correction of the shuttle moving speed VSH is performed by the main scanning motor 17 for moving the carriage 13.
By changing the frequency of the drive signal applied from the driver 89 to the above.

That is, as expressed by the above equation (3), the moving speed VSH of the shuttle is determined by the maximum drive frequency of the drive waveform for driving the head and the print density (print interval) of the image on the print-receiving medium. Normally, the highest frequency of a drive waveform for driving the head 14 and the highest frequency of a drive signal for driving the main scanning motor 17 are synchronized and printed on a one-to-one basis.

Therefore, in the case shown in FIG. 23, it is necessary to correct the highest frequency of the drive waveform for driving the head 14 in accordance with the fluctuation of the printing cycle Td between a plurality of ink droplets due to the change in the viscosity of the ink liquid. Yes, the movement speed VSH of the shuttle can be corrected by correcting the highest frequency of the drive signal for driving the main scanning motor 17 in synchronization with this.

For example, when the head ambient temperature Tmp rises, the viscosity of the ink liquid decreases and the printing cycle Td between a plurality of ink droplets becomes longer, so it is necessary to correct the shuttle moving speed VSH slowly. . Therefore, the head 14
And the highest frequency of the drive signal for driving the main scanning motor 17 synchronized with the frequency.

Conversely, when the head peripheral temperature Tmp decreases, the viscosity of the ink liquid increases and the printing cycle Td between a plurality of ink droplets decreases, so that the shuttle moving speed VSH is corrected faster. There is a need. Therefore, the highest frequency of the drive waveform for driving the head 14 and the highest frequency of the drive signal for driving the main scanning motor 17 synchronized with the frequency are increased (increased).

However, in this case, the main scanning motor 17
It is necessary to change the set value of the highest frequency of the drive signal for driving the ink droplet according to the number of separated ink droplets. For example, when one ink droplet is separated into n ink droplets, the highest frequency of the drive signal for driving the main scanning motor 17 needs to be set to n times the frequency.

Further, with a change in the head ambient temperature Tmp, the printing cycle Td between the plurality of ink droplets fluctuates,
Therefore, when setting and adjusting the maximum frequency Fmax of the drive signal for driving the main scanning motor 17 as described above, the relationship between the printing cycle Td and the maximum frequency Fmax is determined by the above-mentioned (3).
From the expressions and the expression (4), the frequency can be set and adjusted so as to satisfy the following expression (5).

[0111]

(Equation 5)

That is, by setting the maximum frequency Fmax of the drive signal for driving the main scanning motor 17 to a value equal to the reciprocal of the print cycle Td between a plurality of ink droplets, the predetermined appropriate print interval δ0 can be more reliably achieved. Can be maintained.

Next, in another embodiment of the present invention, the parameters of the driving waveform applied to the head 14 are corrected to correct the printing interval δ. That is, the traveling speed V of the shuttle
When the SH is constant at a certain predetermined moving speed VSH0, as shown in FIG. 22, the head peripheral temperature Tmp fluctuates and the viscosity of the ink liquid fluctuates, and the printing cycle Td between the plurality of ink liquids is initialized. When the printing period fluctuates from the predetermined printing period Td0 toward the short printing period Td1 or the long printing period Td2, the relationship between the printing interval δ between a plurality of ink droplets and the printing period Td between the plurality of ink droplets is as shown in FIG. become. Therefore, the printing interval δ can be corrected to a predetermined value by correcting the printing cycle Td between a plurality of ink droplets based on the above equation (4).

In this example, similarly to the case described with reference to FIG. 23, for example, when the head peripheral temperature Tmp decreases and the viscosity of the ink liquid increases, the printing cycle Td between a plurality of ink droplets becomes the initial predetermined value. Is changed to a printing cycle Td1 shorter than the printing cycle Td0. Shuttle travel speed VS
When H remains at the initial predetermined moving speed VSH0,
The printing interval by a plurality of ink droplets becomes narrower (δ0 (d
Point) → δ1 (point f)). As a result, the printing density on the print-receiving medium 3 is increased, and although an image with a relatively high print density can be obtained, image blurring or character collapse occurs, and an appropriate image cannot be obtained. Sometimes.

Conversely, when the temperature Tmp around the head peripheral temperature printing element rises and the viscosity of the ink liquid decreases, the printing cycle Td between a plurality of ink droplets becomes longer than the initial predetermined printing cycle Td0. It fluctuates toward the longer printing cycle Td2. When the shuttle moving speed VSH remains at the initial predetermined moving speed VSH0, the printing interval by a plurality of ink droplets becomes wider (changes from δ0 (point d) to δ2 (point e)). As a result, the print density on the print-receiving medium 3 may be reduced, resulting in an image having a relatively low print density.

Therefore, as described above, the shuttle moving speed VSH is corrected and the printing interval δ by a plurality of ink droplets is adjusted.
However, in this case, since the shuttle moving speed VSH fluctuates, the printing speed always fluctuates depending on the environmental temperature around the head, and in some cases, the printing speed may be reduced.

Therefore, in order to maintain the above-mentioned predetermined printing interval δ0 without changing the printing speed and obtain an appropriate image, even if the head ambient temperature Tmp changes and the viscosity of the ink liquid changes, a plurality of Printing cycle T between ink drops
Printing is performed by directly correcting the changed printing cycle Td so that d does not change. More specifically, the fluctuating printing cycle Td is directly corrected by correcting the parameters of the driving waveform applied to the head (generating and outputting a driving waveform of the corrected parameter).

First, an example of correcting the print cycle Td by correcting the voltage fall time width Tf of the drive waveform will be described with reference to FIGS. 25 and 26. When the magnitude of the applied voltage (applied voltage value) Vp and the voltage application time width Tp in the drive waveform are fixed and only the voltage fall time width Tf is changed, the ejection speed V1 of each ink droplet D1, D2 is changed. , V2 are as shown in FIG.

In the figure, due to the difference in the change of the head ambient temperature Tmp, (a) the ink droplets D1, D2 at the initial temperature
(B) Changes in the ejection speeds V1H and V2H of the ink droplets D1 and D2 at high temperatures, and (c) Discharge speeds V1L and V2L of the ink droplets D1 and D2 at low temperatures. 3 shows changes in three temperature states.

As shown in the figure, in any temperature state, each of the ink droplets D increases with the increase of the voltage fall time width Tf.
1. The ejection speeds V1 and V2 of D2 have the characteristic of gradually decreasing. In particular, when the ejection speed of the ink drops becomes about 4 m / s or less, separation of the ink drops is not observed.

Further, the ejection speeds V1 and V2 of the ink droplets D1 and D2 differ depending on the difference in the temperature around the head.
The initial voltage fall time width Tf0 in the drive voltage waveform is constant, and when the temperature around the head becomes high as shown in the figure, the ejection characteristics of the ink droplets change, and the printing cycle Td2 between each ink droplet is reduced. This is longer than the printing cycle Td0 at the initial temperature (this is represented by the symbol <A>). Also, conversely,
Similarly, when the head peripheral temperature Tmp becomes low, the ejection characteristics of the ink droplets change, and the printing cycle T
d1 becomes shorter than the printing cycle Td0 at the initial temperature (this is represented by the symbol <B>).

Therefore, by utilizing the characteristics shown in FIG. 23 and changing the voltage fall time width Tf of the drive waveform applied to the head, the print cycle Td1 which varies according to the temperature change of the head peripheral temperature. , Td2 can be adjusted to the initial predetermined printing cycle Td0.

That is, when the head peripheral temperature Tmp rises (when it becomes high temperature), the voltage fall time width Tf is made longer than the initial set width Tf0, as shown in FIG. The longer printing cycle Td can be gradually shortened, and by further increasing the voltage fall time width to Tf1, the initial predetermined printing cycle Td can be reduced.
It is possible to correct the coincidence with d0.

On the other hand, when the head peripheral temperature Tmp decreases (when the temperature decreases), the voltage fall time width Tf is made shorter than the initial set width Tf0, as shown in FIG. As described above, the shortened printing cycle Td can be gradually increased, and by further reducing the voltage fall time width to Tf2, the initial predetermined printing cycle Td can be reduced.
It is possible to correct the coincidence with d0.

For example, in the example shown in the figure, the initial voltage fall time width is Tf0, and the two ink droplets D1 and D2 at that time are Tf0.
V1S = 10m /
s, V2S = 7.8 m / s, the time difference between the ink droplets at the initial temperature (the printing cycle Td0 is about 28.2 μm)
s.

The head peripheral temperature Tmp rises (increases in temperature), the viscosity η of the ink liquid decreases, and the printing cycle between ink droplets fluctuates. The fluctuating printing cycle matches the initial predetermined printing cycle Td0. If correction is desired, the discharge speeds V1H and V2H of the two ink droplets D1 and D2 are made substantially equal to the initial discharge speeds V1S and V2S by setting the voltage fall time width Tf to a longer time width Tf1. Vj, and the printing cycle Td between the ink droplets at a high temperature can be made substantially equal to the printing cycle Td0 at the initial temperature.

On the other hand, the head peripheral temperature Tmp decreases (becomes low), the viscosity η of the ink liquid increases, and the printing cycle between the ink droplets fluctuates. When it is desired to correct the coincidence with the period Td0,
By setting the voltage fall time width Tf to a shorter time width Tf2, the discharge speeds V1L and V2L of the two ink droplets D1 and D2 are set to be equal to the initial discharge speeds V1S and V2S.
The printing cycle Td between the ink droplets at a low temperature can be made substantially equal to the printing cycle Td0 at the initial temperature.

Therefore, as shown in FIG. 26, the magnitude of the applied voltage Vp and the length of the voltage application time width Tp in the drive waveform are made constant, and the voltage fall time width Tf0 and the voltage fall time width Tf0 as shown in FIG. The drive waveform having the voltage fall time width Tf1 longer than the voltage fall time width Tf0 as shown in FIG. 5B and the drive waveform having the voltage fall time width Tf0 as shown in FIG. The voltage fall time width Tf2 is also short
Are stored in the ROM 81 in advance.

The head ambient temperature Tmp is detected based on the detection signal from the temperature sensor 90. When the head ambient temperature Tmp is the initial temperature, the drive waveform data of the voltage fall time width Tf0 shown in FIG. Is read out, applied to the waveform generation circuit 87 and applied to the head 14. Also, when the head ambient temperature Tmp is high, FIG.
As shown in the figure, the drive waveform data of the voltage fall time width Tf1 is read out, applied to the waveform generation circuit 87, and applied to the head 14. Further, when the head ambient temperature Tmp is low, the drive waveform data of the voltage fall time width Tf2 is read out as shown in FIG.
7 and applied to the head 14.

In this way, by correcting the length of the voltage fall time width Tf of the parameters of the drive waveform, the fluctuating printing cycle Td can be directly corrected,
Even when the environmental temperature around the head fluctuates, printing can be performed with the printing speed kept constant.

Next, an example of correcting the printing cycle Td by correcting the voltage application time width Tp of the drive waveform will be described with reference to FIGS. 27 and 28. When the magnitude of the applied voltage (applied voltage value) Vp and the voltage fall time width Tf in the drive waveform are fixed and only the voltage application time width Tp is changed, the ejection speeds V1, V2 of the ink droplets D1, D2 are changed. Figure 27
It becomes as shown in.

In the figure, due to the difference in the change of the head ambient temperature Tmp, (a) the ink droplets D1, D2 at the initial temperature
(B) Changes in the ejection speeds V1H and V2H of the ink droplets D1 and D2 at high temperatures, and (c) Discharge speeds V1L and V2L of the ink droplets D1 and D2 at low temperatures. 3 shows changes in three temperature states.

As shown in the figure, in any temperature state, each of the ink droplets D1, D2
It also has the characteristic that the discharge speeds V1 and V2 of D2 increase and decrease.
In particular, when the ejection speed of the ink droplet is about 4 m / s or less, separation of the ink droplet is not observed.

Further, the ejection speeds V1 and V2 of the ink droplets D1 and D2 differ depending on the difference in the temperature around the head.
When the initial voltage application time width Tp0 in the drive voltage waveform is constant and the head peripheral temperature Tmp becomes high as shown in the figure, the ejection characteristics of the ink droplets change. Becomes less than or equal to 4 m / s, and the state changes to a state in which no separation of ink droplets is observed (this is represented by the symbol <A>). Conversely, even when the head peripheral temperature Tmp becomes low, the ejection characteristics of ink droplets similarly change, and the printing cycle Td1 between each ink drop becomes shorter than the printing cycle Td0 at the initial temperature. fluctuate.
(This is represented by the symbol <B>).

Therefore, utilizing the characteristics shown in FIG. 27, the voltage application time width Tp of the drive waveform applied to the head is determined.
Is changed, the printing cycles Td1 and Td2 that fluctuate according to the temperature change of the head peripheral temperature can be adjusted to the initial predetermined printing cycle Td0.

That is, when the head peripheral temperature Tmp rises (increases in temperature), the voltage application time width Tp
Is made shorter than the initial set width Tp0,
As shown in FIG. 27, the ink droplets can be separated and formed from the state where the separation of the ink droplets is no longer observed, the printing cycle Td can be gradually shortened, and the voltage application time width can be further reduced to Tp1. Thus, the initial predetermined printing cycle T
It is possible to correct the coincidence with d0.

On the other hand, when the head peripheral temperature Tmp decreases (when the temperature decreases), the voltage application time width Tp
Is made longer than the initial set width Tp0,
As shown in FIG. 27, the shortened printing cycle Td can be gradually increased, and by further increasing the voltage application time to Tp2, it is possible to correct and match the initial predetermined printing cycle Td0.

For example, in the example shown in the figure, the initial voltage application time width is Tp0, and the discharge speeds V1S, V2S of the two ink droplets D1, D2 at that time are respectively V1S = 9.5 m / s,
When V2S = 6.8 m / s, the time difference between the ink droplets at the initial temperature (the printing cycle Td0 is about 41.7 μs).

The head peripheral temperature Tmp increases (increases in temperature), the viscosity η of the ink liquid decreases, and the printing cycle between the ink droplets fluctuates. The fluctuating printing cycle matches the initial predetermined printing cycle Td0. If correction is desired, the discharge speeds V1S and V2S of the two ink droplets D1 and D2 can be changed by setting the voltage application time width Tp to a shorter time width Tp1, for example, V1H = 12 m / s, V2H = 8 m / s, the printing cycle Td between each ink droplet at a high temperature can be set to about 41.7 μs,
The printing period Td0 at the initial temperature can be completely matched.

On the other hand, the head peripheral temperature Tmp decreases (becomes low), the viscosity (η) of the ink liquid increases, and the printing cycle between the ink droplets fluctuates. When it is desired to correct the printing period Td0, the ejection speeds V1S and V2S of the two ink droplets D1 and D2 can be changed by setting the voltage application time width Tp to a longer time width Tp2. = 7.5 m / s, V
By adjusting each discharge speed to 2L = 5.7m / s,
The printing cycle Td between each ink drop at low temperature is about 41.7μ
s, which can be completely matched with the printing cycle Td0 at the initial temperature.

Therefore, as shown in FIG. 28, the magnitude of the applied voltage Vp and the voltage fall time width Tf in the drive waveform are obtained.
(Tf = 0) is fixed, the drive waveform with the voltage application time width Tp0 as shown in FIG. 3A, and the voltage application time width shorter than the voltage application time width Tp0 as shown in FIG. The data of the drive waveform of Tp1 and the data of the drive waveform of the voltage application time width Tp2 longer than the voltage application time width Tp0 as shown in FIG.

The head ambient temperature Tmp is detected based on the detection signal from the temperature sensor 90. When the head ambient temperature Tmp is the initial temperature, the drive waveform data of the voltage application time width Tp0 shown in FIG. The data is read out, applied to the waveform generation circuit 87, and applied to the head 14. When the head ambient temperature Tmp is high, the drive waveform data for the voltage application time Tp1 is read out, applied to the waveform generation circuit 87 and applied to the head 14 as shown in FIG.
Further, when the head ambient temperature Tmp is low, the drive waveform data of the voltage application time width Tp2 is read out as shown in FIG.
To be applied.

In this manner, by correcting the length of the voltage application time Tp of the parameters of the drive waveform, the fluctuating printing cycle Td can be directly corrected, and the fluctuating printing cycle Td can be corrected. However, printing can be performed with the printing speed kept constant.

Next, an example of correcting the print cycle Td by correcting the magnitude (applied voltage value) of the applied voltage of the drive waveform will be described with reference to FIGS. 29 and 30. FIG. 29 shows the relationship between the ejection speeds V1 and V2 of the ink droplets D1 and D2 when the voltage application time width Tp and the voltage fall time width Tf in the drive waveform are fixed and only the applied voltage value Vp is changed. Become like

Also in this figure, the head ambient temperature Tm is shown in FIG.
Due to the difference in the change in p, (a) changes in the ejection speeds V1S and V2S of the ink droplets D1 and D2 at the initial temperature, and (b) changes in the ejection speeds V1H and V2H of the ink droplets D1 and D2 at the high temperature. change,
(C) The ejection speed V1L of each ink droplet D1, D2 at low temperature,
It shows how the V2L changes in three different temperature states.

[0146] In the figure, in any temperature state, the discharge speeds V1, V2 of the ink droplets D1, D2 increase as the applied voltage value Vp increases. In particular, the separation of the ink droplet D0 starts when the discharge speed V0 of the ink droplet exceeds about 4 m / s. As shown in FIG. 9C, two ink droplets of the ink droplet D1 and the ink droplet D2 are discharged. It will fly with speed.

Also in the same figure, the ejection speeds V1 and V2 of the ink droplets D1 and D2 are different due to the difference in the temperature around the head. For example, the initial applied voltage value Vp0 in the drive waveform is constant, as shown in the figure. When the head peripheral temperature Tmp becomes high, the ejection characteristics of ink droplets change, and the printing cycle Td2 between each ink drop becomes longer than the printing cycle Td0 at the initial temperature (this is represented by the symbol <A>). . Conversely, even when the temperature around the head becomes low, the ejection characteristics of the ink droplets change similarly, and the printing cycle Td1 between each ink drop becomes shorter than the printing cycle Td0 at the initial temperature (this is referred to as a code). <B>).

Therefore, by utilizing the characteristics as shown in FIG. 29 and changing the applied voltage value Vp of the driving waveform applied to the head 14, the printing periods Td1 and Td2 which fluctuate according to the temperature change around the head can be obtained. Initial predetermined printing cycle Td
Correct to 0.

More specifically, when the head ambient temperature Tmp rises (increases in temperature), the applied voltage value Vp is made lower than the initial set width Vp0, whereby FIG. Can be gradually shortened, and by further reducing the applied voltage value Vp1, it is possible to correct substantially the same as the initial predetermined printing cycle Td0.

On the other hand, when the head peripheral temperature Tmp decreases (when the temperature decreases), the applied voltage value Vp is raised from the initial set width Vp0, thereby shortening the voltage as shown in FIG. The printing cycle can be gradually lengthened, and by further increasing the applied voltage value Vp2, it is possible to make a correction substantially coincident with the initial predetermined printing cycle Td0.

For example, in the example shown in the figure, the initial applied voltage value is Vp0, and the ejection speeds V1S and V2S of the two ink droplets D1 and D2 at that time are respectively V1S = 9 m / s and V2S =
In the case of 7 m / s, the time difference (printing cycle) Td0 between each ink droplet at the initial temperature is about 32 μs.

Here, the head ambient temperature Tmp rises (increases in temperature), the viscosity η of the ink liquid decreases, and the printing cycle between the ink droplets fluctuates. If you want to make it equal to Td0,
By setting the applied voltage value Vp to a lower applied voltage value Vp1, the ejection speeds V1H and V2H of the two ink droplets D1 and D2 are obtained.
Can be corrected to an ejection speed substantially equal to each of the initial ejection speeds V1S and V2S, and the printing cycle Td between the ink droplets at a high temperature can be made substantially equal to the printing cycle Td0 at the initial temperature.

Conversely, the ambient temperature of the head decreases (becomes low), the viscosity η of the ink liquid increases, and the printing cycle between the ink droplets fluctuates. If it is desired to correct the coincidence with Td0, the applied voltage value Vp is set to a higher applied voltage value Vp2, so that the ejection speeds V1L and V2L of the two ink droplets D1 and D2 are set to the initial ejection speeds V1S and V2S. The ejection speed can be corrected to substantially the same, and the printing cycle Td between each ink droplet at a low temperature can be corrected.
Can be substantially matched with the printing cycle Td0 at the initial temperature.

Therefore, as shown in FIG. 30, the voltage application time width Tp and the voltage fall time width Tf in the driving waveform are obtained.
(Tf = 0) is fixed, and a driving waveform in which the applied voltage value is Vp0 as shown in FIG. 7A, and a driving waveform in which the applied voltage value Vp1 is lower than the applied voltage value Vp0 as shown in FIG. The data of the waveform and the drive waveform of the applied voltage value Vp2 higher than the applied voltage value vp0 as shown in FIG.
1 in advance.

Then, the head ambient temperature Tmp is detected based on the detection signal from the temperature sensor 90, and when the head ambient temperature Tmp is the initial temperature, the drive waveform data of the applied voltage value Vp0 shown in FIG. To the waveform generating circuit 87 to apply it to the head 14. When the head ambient temperature Tmp is high, the drive waveform data of the applied voltage value Vp1 is read out, applied to the waveform generation circuit 87 and applied to the head 14 as shown in FIG. Further, when the head ambient temperature Tmp is low, FIG.
The drive waveform data of the applied voltage value Vp2 is read out and applied to the waveform generation circuit 87 as shown in FIG.

In this way, by correcting the applied voltage value Vp of the parameters of the driving waveform, the fluctuating printing cycle Td can be directly corrected, and the printing speed can be changed even when the ambient temperature around the head fluctuates. Can always be printed in a constant state.

When the applied voltage value Vp is corrected based on the temperature around the head, the applied voltage value Vp
The slope of the change in the ejection speeds V1 and V2 of the ink droplets D1 and D2 with respect to the voltage fall time Tf or the voltage application time width Tp
Is more gradual than in the case where the correction is made, and accordingly, the applied voltage value Vp can be more finely adjusted. Therefore, there is an advantage that the printing cycle Td can be adjusted more easily and accurately. Also, since the length of the voltage application time for one drive waveform does not change, the range of the maximum drive frequency that can be applied is higher than that of other adjustment methods, and printing operation at a higher drive frequency becomes possible, and higher speed printing is possible. Can be printed on

Therefore, as a method of correcting the printing cycle between the ink droplets with respect to the change in the temperature around the head, it is most preferable to correct the applied voltage value Vp.

Next, an ink jet recording apparatus according to another embodiment of the present invention will be described with reference to FIG. This inkjet apparatus includes a printing unit 101 and a controller unit 102 that controls the printing unit 101 based on an image signal sent from a host. Printing unit 1
01 is a printing paper 103 similar to the above-described embodiment.
And a tube for supplying ink from the ink tank, and supplies ink to the print element (head) 104 via the ink supply tube. The printing element 104 provided with the pressure generating means (driving means)
The carriage 105 is mounted on the motor 1
By driving 07, the print paper 103 moves in a direction orthogonal to the transport direction of the print paper 103 (similar to FIG. 10 described above).

Controller 1 for controlling printing unit 101
Reference numeral 02 denotes a print operation control unit (CPU) 111, a storage unit 112, a timing unit 113, a reception port 114, a print pattern storage unit 115, a head drive circuit unit 116, a driver 117, an ink discharge speed adjustment unit 118, and a head 10.
4 comprises a temperature sensor 119 for detecting the surrounding temperature.

The storage means 112 comprises a RAM for storing a print command and the like included in the image signal, a ROM for storing a program for controlling each section, and the like.
U <b> 111 controls each unit of the controller unit 102 according to the program stored in the storage unit 112. The timer 113 includes a timer or the like, and outputs a timer up signal for controlling the sequence at the time of printing, or sets a flag to notify the elapse of a predetermined time.

The reception port 114 is a serial or parallel communication port for receiving an image signal from the host. The image data contained in the image signal received by the reception port 121 is printed by a RAM or the like. It is stored in the pattern storage means 115. When the print pattern storage means 115 is constituted by a RAM, an address signal,
The print operation processing means (CP
U) The data of the address designated by 111 is sequentially output.

The channel means 121 of the head drive circuit unit 116 selects a channel for discharging ink droplets based on a signal from the CPU 111. The drive signal generation means 122 generates a drive data signal for each nozzle based on the data output selected by the channel selection means 121, and applies an applied voltage value to the drive means for each nozzle as shown in FIG. A drive waveform in which Vp, voltage application time width Tp, and application start timing are defined is generated and output. That is, the driving waveform is determined by the print calculation processing means (CP
U) It outputs in synchronism with the timing pulse output from 111. The driver 123 includes a drive signal generation unit 122
The drive signal output from the head 104 is stepped up, and a drive waveform is applied to required drive means of the head 104.

The driver 117 is a driver for driving the motor 107, and the CPU 111 is a driver for driving the motor 107.
The drive of the motor 107 is controlled via the.

The discharging speed adjusting means 118
The drive signal generated by the drive signal generating means 122 in response to the timing pulse corresponding to the image signal data output from the printer is a signal for ejecting ink droplets at an ejection speed at which a plurality of ink droplets are separated from one ink droplet. Adjust to
This makes it possible to separate and form a plurality of ink droplets from one ink droplet as described with reference to FIG.

To correct the printing interval by correcting the carriage speed (shuttle movement speed) VSH,
The CPU 111 detects the head peripheral temperature based on the detection signal from the temperature sensor 119, and corrects the frequency of the drive signal for the motor 107 that moves and scans the carriage 13 based on the detection result, as described above.

When correcting the printing interval by correcting the parameters of the drive waveform (voltage fall time Tf, voltage application time width Tp, and applied voltage value Vp), the CPU 111 responds to a detection signal from the temperature sensor 119 to correct the printing interval. The temperature around the head is detected, and the parameters of the drive waveform given to the ejection speed adjusting means 118 are corrected based on the detection result.

In the above embodiment, the shapes, arrangements, and forming methods of the nozzles, the pressurizing chambers, the fluid resistance portions, and the common channel liquid chambers of the ink jet head can be appropriately changed. For example, in the above-described embodiment, the edge shooter type inkjet head is formed such that the nozzles eject the ink droplets in a direction intersecting the displacement direction of the diaphragm. A side shooter type inkjet head formed to discharge may be used. Further, the case where the inkjet head is an electrostatic inkjet head has been described as an example, but the present invention can be similarly applied to an inkjet recording apparatus equipped with a piezo type or bubble type inkjet head.

[0169]

As described above, according to the ink jet recording apparatus of the present invention, one ink droplet ejected from the nozzle to the head driving means is separated into a plurality of ink droplets during flight. Since there is provided a means for applying a drive waveform, and a correction means for correcting a printing interval of a plurality of ink droplets on a printing target recording medium based on the ambient temperature of the head,
High-speed recording and high-density recording can be performed without being affected by changes in the ambient temperature, and more stable image quality can be obtained.

Here, the driving waveform is a waveform in which an ink droplet ejected from a nozzle is ejected at an ejection speed at which the ink droplet separates into a plurality of ink droplets during flight. High-density quality images can be recorded at high speed.

In this case, the voltage value of the drive waveform is set to a value that results in the ejection speed at which one ink droplet ejected from the nozzle is separated into a plurality of ink droplets during flight, or the voltage value of the drive waveform By setting the time to a value at which one ink droplet ejected from the nozzle is separated into a plurality of ink droplets during the flight, high-speed printing can be performed more simply and inexpensively. The printing speed can be adjusted flexibly with respect to the printing density.

The correction means corrects the moving speed of the head in the main scanning direction to thereby correct the printing interval of a plurality of ink droplets on the printing recording medium based on the ambient temperature of the head with a simple configuration. can do.

In this case, the correction means corrects the frequency of the drive signal for moving the head, and the printing interval of a plurality of ink droplets on the print-recording medium based on the ambient temperature of the head with a simple configuration. Can be corrected. Here, the correction means can reduce the frequency of the drive signal when the ambient temperature increases, and increase the frequency of the drive signal when the ambient temperature decreases, so that the printing interval can be corrected to be substantially constant. it can. In this case, the correction unit makes the printing interval more accurately and substantially constant by matching the highest frequency value of the drive signal to a frequency value equal to the reciprocal of the time difference between the plurality of ink droplets that changes according to the ambient temperature. Can be corrected.

Further, the correction means corrects the time difference between the plurality of ink droplets until the plurality of ink droplets land, so that the printing interval can be corrected with a simple configuration without fluctuation of the recording speed. it can.

In this case, the correcting means can correct the printing interval with a simple configuration without changing or decreasing the recording speed by correcting the voltage fall time width of the drive waveform. Here, the correction unit increases the voltage fall time width of the drive waveform when the ambient temperature increases, and shortens the voltage fall time width of the drive waveform when the ambient temperature decreases, thereby substantially shortening the printing interval. It can be corrected constantly.

Further, the correction means corrects the voltage application time width of the drive waveform, so that the printing interval can be corrected with a simple configuration without fluctuation or reduction of the recording speed.
Here, the correction unit shortens the voltage application time width of the drive waveform when the ambient temperature increases, and increases the voltage application time width of the drive waveform when the ambient temperature decreases, so that the printing interval becomes substantially constant. Can be corrected.

Further, the correction means corrects the applied voltage value of the drive waveform, thereby correcting the printing interval with a simple configuration with higher accuracy and with a higher drive frequency without fluctuation or reduction in the recording speed. be able to. Here, the correction unit corrects the printing interval to be substantially constant by reducing the applied voltage value of the drive waveform when the ambient temperature increases and increasing the applied voltage value of the drive waveform when the ambient temperature decreases. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of a mechanism section of an ink jet recording apparatus according to the present invention.

FIG. 2 is an explanatory side view of the mechanism.

FIG. 3 is an explanatory cross-sectional view in the longitudinal direction of a diaphragm showing an example of a head of the recording apparatus.

FIG. 4 is an enlarged sectional explanatory view of a main part of the head in the transverse direction of the diaphragm.

FIG. 5 is a block diagram illustrating an example of a control unit of the recording apparatus.

FIG. 6 is a block diagram of a part related to a head drive control unit of the recording apparatus.

FIG. 7 is an explanatory diagram for explaining an operation of the head up to contact with the diaphragm;

FIG. 8 is an explanatory diagram for explaining an operation of the head from a diaphragm restoration;

FIG. 9 is an explanatory diagram illustrating an ink droplet forming process according to the present invention.

FIG. 10 is an explanatory diagram for explaining a dot forming position when the present invention is applied;

FIG. 11 is an explanatory diagram for explaining a driving waveform.

FIG. 12 is an explanatory diagram for explaining the relationship among print density, shuttle speed (carriage speed), and drive frequency.

FIG. 13 is an explanatory diagram illustrating an example of a relationship between an applied voltage value and an ink ejection speed;

FIG. 14 is an explanatory diagram illustrating an example of a relationship between a voltage application time width and an ink ejection speed;

FIG. 15 is an explanatory diagram illustrating an example of formed dots when the voltage application time width and the application start timing are changed.

FIG. 16 is an explanatory diagram for explaining an example of a relationship among an applied voltage value, ink viscosity, and ink ejection speed;

FIG. 17 is an explanatory diagram for explaining a driving waveform and a state transition of each unit in the inkjet head.

FIG. 18 is an explanatory diagram for explaining a pulse width of a driving waveform and an ink droplet ejection characteristic value.

FIG. 19 is an explanatory diagram for explaining pressure fluctuation of the head.

FIG. 20 is an explanatory diagram for explaining pressure fluctuation of the head.

FIG. 21 is an explanatory diagram illustrating a relationship between a head ambient temperature and ink viscosity.

FIG. 22 is an explanatory diagram illustrating the relationship between ink viscosity and ink droplet ejection speed.

FIG. 23 is an explanatory diagram illustrating a relationship between a shuttle movement speed and a printing interval.

FIG. 24 is an explanatory diagram illustrating a relationship between a printing cycle between a plurality of ink droplets and a printing interval.

FIG. 25 is an explanatory diagram illustrating a relationship between a voltage fall time and an ink droplet ejection speed.

FIG. 26 is an explanatory diagram illustrating drive waveforms having different voltage fall times.

FIG. 27 is an explanatory diagram illustrating a relationship between a voltage application time width and an ink droplet ejection speed.

FIG. 28 is an explanatory diagram illustrating driving waveforms having different voltage application time widths.

FIG. 29 is an explanatory diagram illustrating a relationship between an applied voltage value and an ink droplet ejection speed.

FIG. 30 is an explanatory diagram illustrating drive waveforms having different applied voltage values.

FIG. 31 is a block diagram of a control unit of an ink jet recording apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

13: carriage, 14: head, 24: transport roller,
33: paper ejection roller, 40: ink jet head, 41
... first substrate, 42 ... second substrate, 43 ... third substrate, 44 ...
Nozzle groove, 46 pressurizing chamber, 47 fluid resistance section, 48 common flow path liquid chamber, 50 diaphragm, 55 electrode, 87 waveform generating circuit, 88 head drive circuit, 90 temperature sensor, 1
18 ... Discharge speed adjusting means.

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference) 2C056 EA01 EA04 EB07 EB30 EC03 EC07 EC11 EC31 EC37 EC38 EC42 FA02 FA10 HA05 HA16 KC16 KC22 2C057 AF01 AF33 AG54 AG55 AL26 AM03 AM18 AM21 AM22 AM40 AN01 AP02 AP25 AP28 AQ01 AR0408 BA03 BA15

Claims (15)

[Claims] An ink jet recording apparatus equipped with a head having a nozzle for ejecting ink droplets, an ink flow path communicating with the nozzle, and a driving means for generating energy for pressurizing ink in the ink flow path. , One of the nozzles discharged from the nozzle to the driving means of the head.
Means for applying a drive waveform in which one ink droplet is separated into a plurality of ink droplets during flight, and correction for correcting a printing interval of the plurality of ink droplets on a recording medium based on an ambient temperature of the head. An ink jet recording apparatus comprising: 2. The ink jet recording apparatus according to claim 1, wherein the driving waveform causes the ink droplet to be ejected at an ejection speed at which one ink droplet ejected from the nozzle is separated into a plurality of ink droplets during flight. An ink jet recording apparatus having a waveform. 3. The ink jet recording apparatus according to claim 2, wherein the voltage value of the driving waveform is set to a value at which a discharge speed at which one ink droplet discharged from the nozzle separates into a plurality of ink droplets during flight. An ink jet recording apparatus characterized by being set. 4. The ink jet recording apparatus according to claim 2, wherein the voltage application time of the drive waveform is a discharge speed at which one ink droplet discharged from the nozzle separates into a plurality of ink droplets during flight. An ink jet recording apparatus, wherein: 5. The ink jet recording apparatus according to claim 1, wherein said correction means corrects a moving speed of said head in a main scanning direction. 6. An ink jet recording apparatus according to claim 5, wherein said correction means corrects a frequency of a drive signal for moving said head. 7. The ink jet recording apparatus according to claim 6, wherein said correction means reduces the frequency of said drive signal when ambient temperature increases, and decreases the frequency of said drive signal when ambient temperature decreases. An ink jet recording apparatus characterized by increasing the number of ink jet recordings. 8. The ink jet recording apparatus according to claim 7, wherein said correction means sets a maximum frequency value of said drive signal to a frequency equal to a reciprocal of a time difference between said plurality of ink droplets which changes according to an ambient temperature. An ink jet recording apparatus characterized by making the value coincide with the value. 9. The ink jet recording apparatus according to claim 1, wherein the correction unit corrects a time difference between the plurality of ink droplets until the plurality of ink droplets land. Inkjet recording device. 10. The ink jet recording apparatus according to claim 9, wherein said correction means corrects a voltage fall time width of said drive waveform. 11. The ink jet recording apparatus according to claim 10, wherein the correction unit increases a voltage fall time width of the drive waveform when an ambient temperature increases.
An ink jet recording apparatus, wherein when the ambient temperature decreases, the voltage fall time width of the drive waveform is shortened. 12. The ink jet recording apparatus according to claim 9, wherein said correction means corrects a voltage application time width of said drive waveform. 13. The ink jet recording apparatus according to claim 12, wherein said correction means shortens the voltage application time width of said drive waveform when ambient temperature increases, and reduces said drive waveform width when ambient temperature decreases. An ink jet recording apparatus characterized by increasing a voltage application time width. 14. The ink jet recording apparatus according to claim 9, wherein said correction means corrects an applied voltage value of said drive waveform. 15. An ink jet recording apparatus according to claim 14, wherein said correction means reduces the applied voltage value of said drive waveform when ambient temperature increases, and applies said drive waveform when ambient temperature decreases. An ink jet recording apparatus characterized by increasing a voltage value.