JP2000168089A - Method and apparatus for ink-jet printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable preferable ejection without generating ejection failure of ink droplets such as droplet split by time division of an ejection energy generating means into a plurality of groups in a predetermined driving cycle, and providing a driving means for providing a predetermined relationship in the driving interval among the groups. SOLUTION: A CPU 10 controls each part of the apparatus according to a processing procedure stored in a ROM 10A and a work area of a RAM 10B. The CPU 10 supplies driving data of a heat generating member and a driving signal to a head driver 30A so that a printing head 30 ejects ink droplets. The CPU 10 controls a carriage by a motor 20 via a motor driver 20A as well as a paper feeding motor by a motor driver 50A for the time division drive of an energy generating means in a plurality of groups. Among a plurality of driving intervals of the groups, the driving interval in the groups to be driven later is provided larger than the driving interval in the groups to be driven earlier so as to prevent generation of ejection with droplet split.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing apparatus for printing an image by discharging ink and an ink jet printing method.

[0002]

2. Description of the Related Art In recent years, the performance of ink jet printing apparatuses has been remarkably improved, and high-speed printing has been realized as much as laser beam printing apparatuses. Also, with the increase in the processing speed of personal computers and the spread of the Internet, there is an increasing demand for faster color image printing.

FIG. 4 is a sectional view of a main part of an ink jet head provided in a bubble jet print type ink jet printing apparatus. In the ink jet head, the ink is rapidly heated and vaporized by a heating element (electrothermal conversion element) 1, and the pressure of bubbles generated at that time causes a discharge port 3 formed by an orifice plate 2.
Has a nozzle structure for ejecting ink droplets 4 from the nozzles. However, the ink droplets 4 in FIG. 4 are broken due to defective ejection, which will be described later. When the ink droplets 4 are discharged satisfactorily, such broken balls do not occur. In such an ink jet head, bubbles generated in the ink are:
After being cooled by the surrounding ink, the vapor of the ink in the air bubbles condenses and returns to a liquid, and eventually disappears. The ink discharged from the discharge port 3 and consumed is supplied to the ink flow path 5.
Through the ink supply path 6.

FIG. 2 is an explanatory diagram of a specific configuration example of the ink jet head having the nozzle structure of FIG. A large number of ink flow paths 5 are branched right and left in FIG. 2 from the ink supply path 6, and a heating element 1 as an ejection energy generating means as shown in FIG. It is arranged. The length of each ink flow path 5 is not uniform but slightly shifted. This is to enable high-density printing by shifting the position of the ejection port 3. The center of the discharge port 3 and the center of the heating element 1 are located on the same vertical axis in FIG. Therefore, the distance from the ink supply path 6 to the center of the ejection port 3 is equal to the distance from the ink supply path 6 to the center of the heating element 1 (“distance between C and H”).

In the ink jet head of this embodiment, a total of 2
56 ink flow paths 5 are formed. In FIG. 2, only 32 of them are shown. These ink flow paths 5 include an even-numbered flow path on the left side in FIG. 2 (hereinafter, referred to as an “even-numbered flow path”) and an odd-numbered flow path on the right side in FIG.
"Odd channel"). Further, the even-numbered flow path is divided into 16 blocks (1st to 16th blocks) of 8 lines, and similarly, the odd-numbered flow paths are also divided into 16 blocks of 8 lines (1st to 16th blocks).
Are divided into At the time of printing, a total of 16 heating elements 1 in the same block of the even and odd channels are used.
Are simultaneously driven, and the heating elements 1 are sequentially driven from the first block to the sixteenth block. In this manner, the heating element driving is performed in a time-division manner with a total of 16 heating element driving per block as one cycle. Such a time-division driving suppresses the instantaneous driving current value.

[0006] The even-numbered flow paths are divided into blocks with a shift of 16 nozzles. That is, even passages are seg0,
, 224, and 16 nozzles in the first block, seg10, 42, 74,.
234 is the second block, seg20, 52, ..., 2
44 is the third block, seg30, 62,..., 25
4 is the fourth block, seg6, 40, ..., 232 is the fifth block, seg18, 50, ..., 242 is the sixth block, seg28, 60, ..., 252 is the seventh.
, 230 are the eighth block, seg16, 48, ..., 240 are the ninth block, seg26, 58, ..., 250 are the tenth block, seg4, 36, ... 228 is an eleventh block, seg14, 46, ..., 238 is a twelfth block, seg24, 56, ..., 248 is a thirteenth block, seg2, 34, ..., 226 is a fourteenth block, , 236 are divided into a fifteenth block, and seg22, 54, ..., 246 are divided into a sixteenth block.

Similarly, the odd-numbered flow paths are divided into blocks with a shift of 16 nozzles. That is, the odd path is s
eg, 33, 65, 97, 129,..., 225 are in the first block, seg11, 43, 75,
235 is a second block, seg21, 53,.
.. 245 is the third block, seg31, 63,.
255 is the fourth block, seg7, 41, ...,
233 is the fifth block, seg 19, 51,..., 2
43 is the sixth block, seg 29, 61,..., 25
.., 231 are an eighth block, seg 17, 49,..., 241 are a ninth block, seg 27, 59,.
0 block, seg5, 37, ..., 229 are eleventh
Blocks, seg15, 47, ..., 239 are twelfth
Blocks, seg25, 57, ..., 249 are thirteenth
, 227 are divided into the 14th block, seg13, 45, ..., 237 are divided into the 15th block, and seg23, 55, ..., 247 are divided into the 16th block.

In FIG. 2, the center of the discharge port 3 of seg0 (the center of the heating element 1) is set as a reference in the direction of the arrow x to the center of the discharge port 3 of another even-numbered passage (the center of the heating element 1). Are distances aL, bL, cL..., And the distances to the centers of the discharge ports 3 of the odd-numbered passages (the centers of the heating elements 1) are aR, bR, cR.

In the case of a serial type ink jet printing apparatus, a head having such a configuration is provided at a position facing the medium to be printed, and the print data is moved while moving the head in the main scanning direction indicated by an arrow x in FIG. The image is printed on the print medium by driving the head in a time-division manner to discharge the ink droplets 4 from the discharge ports 3 based on the above. In addition, by transporting the print medium in the sub-scanning direction that intersects with the main scanning direction, an image is printed over the entire surface of the print medium.

Now, the head shown in FIG.
When time-division driving is performed based on the print data corresponding to 31, a drive pulse is applied to each heating element 1 in order from the first block to the sixteenth block, as described above.
In this case, the drive interval for each block is, for example, a uniform 5.9 μsec. Also, in the even number flow path,
A seg with a long C-H distance is driven first, and a seg with a short C-H distance is driven first in an odd-numbered flow path.

[0011]

In the ink flow path 5 of such a head, pressure fluctuations and vibrations occur in the process of generation of bubbles, ejection of ink droplets, disappearance of bubbles, and replenishment of ink. . Since all the ink flow paths 5 are communicated with each other by the ink supply path 6, the influence of ink droplet ejection in the other ink flow paths 5 is transmitted. For example, as in seg22 of the sixteenth block, the pressure in the ink flow path 5 having a short CH distance changes as shown in FIG. The horizontal axis in FIG. 3 is the elapsed time since the heating element 1 of the first block was driven, and the vertical axis is the meniscus position of the ink at the ejection port 3. The plus side means that the meniscus protrudes outside the ejection port 3, and the minus side means that the meniscus retreats inside the ejection port 3. In the case of seg22 of the 16th block in FIG. 3, the meniscus bulge is increased by the influence of the driving of the 1st block to the 15th block before it is driven.

As a result of intensive studies conducted by the present inventor, it has been found that, when the meniscus bulges more than 3 μm from the discharge port 3, a ball crack discharge in which the ink droplet 4 breaks as shown in FIG. 4 occurs. Was. The ink droplets 4 ejected in this manner are larger than other normal ink droplets, and cause black streaks in a printed image on a print medium.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet printing apparatus and an ink jet printing apparatus capable of driving an ink jet head in a time-division manner to discharge ink droplets satisfactorily without causing defective ejection of ink droplets such as broken balls. It is to provide a method.

[0014]

The ink jet printing apparatus according to the present invention drives each of the ejection ports by driving ejection energy generating means provided corresponding to a plurality of ink flow paths respectively connected to the ejection ports. In an inkjet printing apparatus that prints an image on a print medium using an inkjet head that can eject ink from, within a predetermined drive cycle, the plurality of ejection energy generating units are time-divisionally driven into a plurality of groups, And a driving unit for increasing a driving interval between groups driven later than a driving interval between groups driven first among a plurality of driving intervals between groups.

[0015] The ink jet printing method of the present invention comprises:
By driving the ejection energy generating means provided corresponding to the plurality of ink flow paths respectively connected to the ejection ports, an image is printed on a printing medium using an inkjet head capable of ejecting ink from each of the ejection ports. In the ink jet printing method for printing, within a predetermined driving cycle, the plurality of ejection energy generating units are time-divisionally driven into a plurality of groups, and are driven first among a plurality of driving intervals between the groups. The driving interval between groups driven after the driving interval between groups is set to be larger.

[0016]

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

FIG. 5 is a schematic perspective view of an ink jet printing apparatus to which the present invention can be applied.

In the ink jet printing apparatus 100, the carriage 101 is slidably engaged with two guide shafts 104 and 105 extending parallel to each other. Thus, the carriage 101 reciprocates in the main scanning direction indicated by the arrow x along the guide shafts 104 and 105 by the driving motor and a driving force transmission mechanism such as a belt for transmitting the driving force (neither is shown). Is done. Carriage 1
In 01, an inkjet unit 103 is mounted. The unit 103 has an ink jet head having the same configuration as in FIGS. 2 and 4 described above, and an ink tank as an ink container for storing ink used in the head. The head and the ink tank are configured to be detachable individually or integrally.

A sheet 106 as a medium to be printed is inserted through an insertion port 111 provided at the front end of the apparatus, and after the transport direction is reversed, an arrow is fed by a feed roller 109 below the moving area of the carriage 101. y
In the sub-scanning direction. The head mounted on the carriage 101 prints on a print area on the sheet 106 supported by the platen 108 as the head moves.

As described above, while the printing accompanying the movement of the carriage 101 in the main scanning direction, that is, the printing having the width corresponding to the width of the ejection port array of the head, and the conveyance of the paper 106 in the sub-scanning direction are alternately repeated. Printing is performed on the entire sheet 106, and then the sheet 106 is discharged to the front of the apparatus.

At the left end of the movable area of the carriage 101, there is provided a recovery system unit 110 which can face the head on the carriage 101. The non-printing operation allows the recovery system unit 110 to perform operations such as capping each ejection port of the head and suctioning ink from each ejection port. The predetermined position at the left end of the apparatus is set as the home position of the head.

On the other hand, an operation unit 107 having a switch and a display element is provided at a right end of the apparatus. The switch is used for turning on / off the power of the apparatus, setting various print modes, and the like, and the display element displays various states of the apparatus.

FIG. 6 is a block diagram of a control system of the ink jet printing apparatus of FIG.

In FIG. 6, a CPU 10 executes a control process of operations of each section of the apparatus, a data process, and the like. ROM
The processing procedure and the like are stored in the RAM 10B.
Is used as a work area for executing the processing.

The ink jet head 30 is configured as shown in FIGS. 2 and 4 described above, and the CPU 10 supplies drive data and a drive control signal of the heating element 1 to the head driver 30A to discharge ink droplets. Is performed. The CPU 10 controls the drive interval of the time-division drive of the print head 30 as described later. Also, CP
U10 controls a carriage motor 20 for moving the carriage 101 via a motor driver 20A and a paper feed (PF) motor 5 for rotating a feed roller 109 via a motor driver 50A.
Control 0.

In the present embodiment, as described above, the head is divided into 16 blocks and time-divisionally driven using a head having the same configuration as that shown in FIGS. That is, a total of 256 ink flow paths 5 are formed in the print head, and the even flow paths are divided into 16 blocks (1st to 16th blocks) each having 8 ink paths. Also, 8 blocks each of 16 blocks (from the first block to the first block)
6 blocks). At the time of printing, a total of 16 heating elements 1 in the same block of the even and odd channels are simultaneously driven, and the heating elements 1 are sequentially driven from the first block to the 16th block. In this way, time division driving is performed with the heating element driving of a total of 16 times for each block as one cycle.

However, according to the present invention, in such time-division driving, the driving intervals are made different.

FIG. 1 is a time chart for explaining the drive timing of the head.

In the case of this example, the driving interval between the first block and the second block is 4.0 μsec, the driving interval between the second block and the third block is 4.5 μsec,
The drive interval between the block and the fourth block is 5.0 μs
ec, and similarly, the drive interval between adjacent blocks is increased by 0.5 μsec, and the 15th block and the first
The drive interval between the six blocks is 11.0 μsec. The width of each drive pulse is 3 μsec. Therefore, the time T from the start of the application of the drive pulse of the first block to the end of the application of the drive pulse of the sixteenth block is:
4.0 + 4.5 + 5.0 + ... + 11.0 + 3.0 =
115.5 (μsec). In the case of this example, the driving frequency of the head in which the driving from the first block to the sixteenth block is one cycle is 8.4 KHz.
(= 1/119 μsec). The driving frequency is
The value must be smaller than the reciprocal of the time T.

As described above, by gradually increasing the driving interval of the time-division driving, the protrusion of the meniscus of the ink to the outside of the ejection port 3 can be suppressed to less than 3 μm.
As shown in FIG. 4, good prints without black streaks were produced without the occurrence of ball crack discharge. The reason is that by gradually increasing the drive interval of the time-division drive, the time during which the vibration of the meniscus attenuates can be increased.

Incidentally, if the driving interval of the time-division driving is uniformly increased in order to suppress the protrusion of the meniscus from the discharge port 3 as described above, the first first
The time required from the start of driving of the block to the end of driving of the last sixteenth block becomes extremely long. Therefore, in this case, the driving frequency of the head is extremely reduced, and the printing speed is reduced. On the other hand, the degree of meniscus protrusion from the discharge port 3 is the first
It is small in blocks and large in the last few blocks.

Therefore, gradually increasing the drive interval of the time-division drive as in the present embodiment is intended to increase the printing speed and to surely prevent the meniscus from protruding from the ejection port 3. Become. Further, only the drive interval between the last several blocks may be increased.

Further, according to the drive interval of the time division drive,
By setting the position of the ejection port 3 of each block in the x direction in FIG. 2, printability can be further improved. In the configuration of FIG. 2, the discharge ports 3 of the n-th block and the discharge ports 3 of the (n + 1) -th block are arranged at equal intervals in the arrow x direction. However, as described later, by arranging the ejection ports 3 of each block at unequal intervals in proportion to the drive interval of the time-division drive, the landing position of the ink droplet on the print medium is determined with higher accuracy. be able to.

In printing an image, the ink jet head having the structure shown in FIG. 2 can be driven in a time-division manner as follows.

That is, in one driving cycle from the first block to the sixteenth block, an arrow x is formed by ink droplets ejected from the ejection ports 3 of the 128 even-numbered flow paths.
Thinned pixels for one line perpendicular to the direction (hereinafter referred to as “first
), And ink droplets ejected from the ejection openings 3 of the 128 odd-numbered flow paths cause another one line of thinned pixels (hereinafter, referred to as “second line”) orthogonal to the arrow x direction. By repeating such a drive cycle with the movement of the head, the first and second thinning lines complement each other and are completed one by one. Images can be printed. In the head of FIG. 2, the discharge ports 3 are arranged so as to correspond to the conventional time-division driving, that is, the conventional time-division driving in which the driving interval is constant (5.9 μsec). When the drive interval of the time-division drive is gradually increased, 1
There is a possibility that the landing position of the ink droplet may be shifted within the allowable formation range of the pixels for the line. Therefore, in the present invention, in order to suppress such a displacement of the landing position, the ejection port 3 of the n-th block and the ejection port 3 of the (n + 1) -th block in the direction of the arrow x are set in proportion to the drive interval of the time division drive. Are arranged at unequal intervals, the landing position of the ink droplet can be determined with higher accuracy.

As a method of driving the head, various methods other than the method of forming the first and second thinning lines in one driving cycle from the first block to the sixteenth block as described above may be employed. it can. For example, in one driving cycle, three or more pixel lines orthogonal to the arrow x direction may be formed.

(Second Embodiment) In the head of FIG. 2, from the first block to the tenth block, the drive intervals between the blocks are all set at a constant 4.0 μsec, and the first block is used.
The drive interval between block 0 and block 11 is 40
The pause time is set as μsec. This 40μsec
During the idle time, the vibration of the meniscus of the discharge port in all the blocks is reduced to a negligible level. Thereafter, from the eleventh block to the sixteenth block, the drive intervals between the blocks are all constant at 4.0 μsec.

In the case of this example, the period from the start of driving the first block to the end of driving of the sixteenth block is 99.0 μsec.
Becomes However, the width of the drive pulse is 3.0 μsec.

(Other Embodiments) The drive intervals between the blocks from the first block to the sixteenth block of the head are all different from each other as in the first embodiment described above, and are gradually increased. Alternatively, they may be set differently for each predetermined number of units, and gradually increased. In addition, among the drive intervals between the blocks from the first block to the sixteenth block, the drive interval between the blocks is set to be large especially only in the latter block which is easily affected by other blocks. Is also good.

Various means such as a piezo element and the like can be used as the discharge energy generating means for discharging the ink droplets, in addition to the heating element 1 as an electrothermal converter.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet printing system. An excellent effect is obtained in a print head (hereinafter, also referred to as a "recording head") and a printing apparatus (hereinafter, also referred to as a "recording apparatus") of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As this pulse-shaped drive signal, those described in U.S. Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

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

It is preferable to add a recording head ejection recovery unit, a preliminary auxiliary unit, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

The type and number of recording heads to be mounted are, for example, not only one provided for a single color ink but also a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent the temperature rise due to thermal energy by using the energy of the state change from the solid state of the ink to the liquid state, or to prevent the ink from evaporating, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not limited to those used as image output terminals of information processing equipment such as computers, copying apparatuses combined with readers and the like, and facsimile apparatuses having a transmission / reception function. It may take a form.

[0050]

As described above, according to the present invention, when a plurality of ink ejection energy generating means in an ink-jet head are driven in a time-division manner, they are driven first in each driving interval within a predetermined driving cycle. By increasing the drive interval between groups driven after the drive interval between groups, it is possible to suppress the effect of ink pressure fluctuations in the plurality of branched ink flow paths, and as a result, such as ball cracking Ink droplets can be satisfactorily ejected without causing defective ink droplet ejection.

[Brief description of the drawings]

FIG. 1 is a time chart for explaining drive timing of time-division driving according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a nozzle structure of an inkjet head to which the present invention can be applied.

FIG. 3 is an explanatory diagram of a fluctuation of a meniscus of an ink jet head in a conventional printing apparatus.

FIG. 4 is a sectional view of a main part of an inkjet head to which the present invention can be applied.

FIG. 5 is a perspective view of the printing apparatus according to the first embodiment of the present invention.

FIG. 6 is a block diagram of a control system of the printing apparatus in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 heating element (electric heat conversion element) 2 orifice plate 3 discharge port 4 droplet 5 ink flow path 6 ink supply path 10 CPU 10A ROM 10B RAM 20 carriage motor 20A motor driver 30 print head 30A head driver 50P. F motor 50A motor driver

Claims (11)

[Claims] An ink jet head capable of discharging ink from each of the discharge ports by driving a discharge energy generating means provided corresponding to a plurality of ink flow paths respectively communicating with the discharge ports, In an ink-jet printing apparatus for printing an image on a print-receiving medium, within a predetermined drive cycle, the plurality of ejection energy generating means are time-divisionally driven into a plurality of groups, and among a plurality of drive intervals between each group, An ink jet printing apparatus, comprising: a driving unit for increasing a driving interval between groups driven later than a driving interval between groups driven first. 2. The ink-jet printing apparatus according to claim 1, wherein said driving means gradually increases said plurality of driving intervals within said predetermined driving cycle. 3. The method according to claim 2, wherein the drive unit sets a pause time for damping the vibration of the ink in the ink flow path as the drive interval substantially at an intermediate time within the predetermined drive cycle. 2. The inkjet printing apparatus according to 1. 4. The ink-jet printing apparatus according to claim 1, wherein the ink-jet head has a plurality of the ink flow paths branched on both sides of an ink supply path. 5. A moving means for relatively moving the ink jet head and the print medium, wherein the plurality of ejection ports of the ink jet head have different positions in the relative movement direction for each of the groups. Item 5. An inkjet printing apparatus according to any one of Items 1 to 4. 6. A first moving means for relatively moving the ink jet head and the print medium in the main scanning direction, and a relative movement of the ink jet head and the print medium in a sub scanning direction intersecting the main scanning direction. Second
5. The inkjet printing apparatus according to claim 1, wherein the plurality of ejection ports of the inkjet head have different positions in the main scanning direction for each of the groups. 6. 7. The ink jet printing apparatus according to claim 1, wherein the ejection energy generating means is an electrothermal converter that applies thermal energy to the ink. 8. The drive unit sets at least one of a plurality of drive intervals within the predetermined drive cycle to be larger than the other, so as to increase the amount of meniscus protrusion of the ink from the discharge port to 3 μm. The inkjet printing apparatus according to claim 7, wherein the size of the ink jet printing apparatus is also reduced. 9. An ink jet head capable of discharging ink from each of said discharge ports by driving discharge energy generating means provided corresponding to a plurality of ink flow paths respectively connected to said discharge ports, In an ink-jet printing method for printing an image on a print-receiving medium, within a predetermined drive cycle, the plurality of ejection energy generating means are time-divisionally driven into a plurality of groups, and among a plurality of drive intervals between each group, An ink-jet printing method characterized in that a drive interval between groups driven later is made larger than a drive interval between groups driven first. 10. The ink-jet printing method according to claim 9, wherein the plurality of drive intervals within the predetermined drive cycle are gradually increased. 11. The ink jet printer according to claim 9, wherein a pause time for damping the vibration of ink in the ink flow path is set as the drive interval at a substantially intermediate timing within the predetermined drive cycle. Printing method.