JPH08164602A - Ink jet recorder - Google Patents

Abstract

PURPOSE: To prevent linearity in a main scan direction to be impaired even though an interlaced driving system carrying out high speed printing is adopted. CONSTITUTION: A part of straight lines printed on recording paper with a recording head having 64 nozzles is schematically represented. When one straight line 20a is printed in a main scan direction, one straight line is not printed with 64 nozzles driven during one printing cycle T, and one straight line is printed by using ink drops jetted from 64 nozzles during 13 cycles. As for the straight line 20a, nozzles 1-5 are driven during an initial first printing cycle, and printing is carried out on an extended line of the straight line 20a printed during the initial printing cycle. The printing is successively carried out, printing is carried out on the extended line of the same straight line 20a with nozzles 60-64 during the last 13th printing cycle, and one straight line is printed with all nozzles.

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 head for recording by ejecting an ink droplet from a nozzle by an ink droplet ejecting means provided in a flow path corresponding to the nozzle.

[0002]

2. Description of the Related Art The ink jet recording system is capable of high-speed recording and produces almost no noise during recording.
Since it can print on plain paper and does not require fixing processing, it is drawing attention because it can be downsized.

In the ink jet recording system, an electro-mechanical conversion element (for example, a piezoelectric element) is used as a means for ejecting ink from a nozzle, and an ink droplet is ejected by a motion associated with mechanical deformation due to an input signal. There is a so-called thermal ink jet method in which an electric-heat conversion element (heater) is used and a voltage pulse is applied to the heater to heat the heater, and the generated heat ejects ink droplets by the pressure of a vapor bubble generated on the heater. .

FIG. 13 shows an example of the thermal ink jet recording head disclosed in Japanese Patent Laid-Open No. 155020/1993. FIG. 13 (A) is a sectional view taken perpendicularly to the axial direction of the channel groove. 13B is B- of FIG.
A plan view taken along line B and FIG. 13C are front views seen from the nozzle side. In the figure, 1 is a channel substrate, 2 is a heater substrate, 3 is a channel groove, 4 is an ink reservoir, 5 is a nozzle, 6 is an unetched portion, 7, 7a, 7b and 7c are heaters, 8 is an insulating layer, and 9 is Thick film resin layer, 10 is the first recess,
Reference numeral 11 is a second concave portion, 12 is a partition wall, 13 is an ink droplet, 14
Is a recording medium, 15 is an ink supply port, and P is a nozzle interval.

A channel groove 3 and an ink reservoir 4 are formed in the channel substrate 1 by anisotropic etching, and the opening of the channel groove 3 serves as a nozzle 5. A heater 7 is provided on the heater substrate 2, and electrodes for supplying a drive signal to the heater 7, a protective film, etc. are formed, but details of these are omitted. Further, on the heater substrate 2, an insulating layer 8 and a thick film resin layer 9 are formed. These two substrates are joined together and cut into individual head chips to separate them, thereby forming a recording head.

The ink supplied from the ink supply port 15 to the ink reservoir 4 is guided to the channel groove 3 which is an ink flow path through the second recess 11, and the heater provided at the bottom of the first recess 10. The pressure of the bubble generated by the heat generation of the recording medium 1 causes ink droplets to form ink droplets from the nozzle 5.
4 is printed and printing is performed.

It is conceivable to increase the frequency at which ink droplets are repeatedly ejected from one nozzle as means for realizing higher-speed printing using such an ink jet recording head. However, the ink must be refilled in the flow path from the ejection of an ink drop to the ejection of the next ink drop, and therefore the repetition frequency cannot be increased too high. At present, the upper limit of the frequency is considered to be 4 to 6 kHz in a head corresponding to a resolution of 300 spi.

In order to improve the upper limit of the repetition frequency, the flow passage structure in the head is devised and the driving sequence is devised. As a device of the driving order, there is a so-called interlaced driving system as described in, for example, Japanese Patent Laid-Open No. 61-266253.

FIGS. 14 and 15 are explanatory views of a heater driving method in the recording head, and FIGS.
(A) is a drive voltage of the heater, FIG. 14 (B), FIG.
FIG. 7B is an explanatory diagram of pixels printed on the recording medium.
In the figure, 5a, 5b, 5c, 5d, 5e are nozzles arranged in order, 7a, 7b, 7c, 7d, 7e are heaters for each nozzle, 16 is a drive pulse, 17a, 17b, 17c, 17
d and 17e are pixels, t is a drive pulse cycle (second), and P is a nozzle interval.

FIG. 14 (A) shows a sequential drive system which is not the interlace drive system. In the sequential driving method, the heaters corresponding to the nozzles are driven in the order of arrangement from the end. When the heaters 7a, 7b, 7c, 7d, and 7e corresponding to the nozzles 5a, 5b, 5c, 5d, and 5e are sequentially driven by the drive pulse 16 having the cycle t, as shown in FIG. The pixels 17a, 17b, 17c, 17d and 17e are printed obliquely side by side. FIG. 14B shows the nozzle 5a,
It shows the case where the recording head having 5b, 5c, 5d, and 5e moves from the lower side to the upper side of the drawing, or the recording medium moves from the upper side to the lower side. In this case, the driving direction of the heater is called the main scanning direction, and the relative moving direction of the print medium and the print head is called the sub-scanning direction.
Therefore, in this example, the nozzles 5a, 5b, 5c, 5
heaters 7a, 7b, 7c, 7d, 7 corresponding to d, 5e
It can be said that e is sequentially driven by one scan in the main scanning direction.

The printing condition on the recording medium will be described. The heater 7a is driven and the pixel 17a is printed. After t seconds, the heater 7b is driven and the pixel 17b is printed. However, the pixel 17b is printed with a shift distance of the recording medium and the recording head from the pixel 17a for t seconds, It is printed on the recording medium at a position delayed by t in the sub-scanning direction. Hereinafter, the pixels 17c, 17d, 17
e is also printed at a position sequentially delayed by the amount corresponding to t. Since the nozzles 7a, 7b, 7c, 7d, 7e are arranged apart from each other by the nozzle interval P, the printed pixels 17a, 1
7b, 17c, 17d and 17e are printed while being inclined as shown in FIG.

In the sequential drive system, the nozzles that eject ink droplets are adjacent to the nozzles that eject ink droplets immediately before, so it takes time to refill ink and is not suitable for high-speed printing. Is.

On the other hand, in the interlace drive system in which the adjacent heaters are driven as far apart as possible,
Since the nozzle that ejected the ink immediately before is away from the nozzle that is trying to eject the ink droplet, the refill time can be shortened, and the repetitive frequency can be set higher than when the adjacent heaters are continuously driven. It is known that it can be increased up to about 2 times.

FIG. 15A shows a driving sequence of an example of the interlaced driving method. In this example, each nozzle 5a,
Each heater 7a, 7 corresponding to 5b, 5c, 5d, 5e
b, 7c, 7d and 7e are drive pulses 16 having a cycle t,
It is driven every two. That is, the heaters 7a, 7d,
The order is 7b, 7e, 7c. As shown in FIG. 15B, the printing status on the recording medium is for adjacent pixels 1
7a, 17b and 17c are separated from each other by a factor of t in the sub-scanning direction, pixels 17c to 17d are separated from the pixel in the sub-scanning direction by a factor of 3 in the sub-scanning direction, and pixels 17d to 17e are t in the sub-scanning direction. The pattern is twice as much apart.

In the interlace drive system, as described above, the distance from a specific nozzle to another nozzle,
After the heater corresponding to a specific nozzle is driven,
Since the relationship with the time until the heaters corresponding to the other nozzles are driven is not constant, as shown in FIG. 15B, the dot position in the main scanning direction is displaced on the recording medium, for example, the recording is performed. Ink drops from all nozzles on the head
When a straight line is printed in the main scanning direction, a concavo-convex (jagged) pattern is formed, and there is a problem that linearity is impaired.

Increasing the number of nozzles in the recording head is also a means for realizing high-speed printing. For example, it is conceivable to increase the number of nozzles corresponding to the width of the recording paper. In this case, there are a method of covering the entire width of the recording paper with one recording head, that is, a method of using an elongated head and a method of linearly connecting a plurality of recording heads to cover the entire width of the recording paper. is there.

In the former case of using the elongated head, the thermal ink jet recording head usually uses Si as the substrate material, so that, for example, an A4 short size (2
To produce a recording head corresponding to 10 mm), a Si wafer of about 203.2 mm (8 inches) or more is required, and the number of heads that can be produced from one wafer is extremely small. The manufacturing cost is extremely high. Further, since the number of nozzles per head increases, it is very difficult to manufacture a head in which all nozzles, heaters, wirings, etc. are defect-free.

On the other hand, the latter method of linearly connecting a plurality of recording heads makes it possible to relatively easily form a recording head corresponding to the paper width using a recording head manufactured by the conventional technique. FIG. 16 shows an example thereof.

FIG. 16A is a view seen from the nozzle side, and FIG.
6B is a view seen from the ink supply port side. 3 in the figure
Is a channel groove, 4 is an ink reservoir, 5 is a nozzle, 15
Is an ink supply port, 18 is a recording head, and 19 is an end nozzle. The recording head 18 has the same structure as the recording head described with reference to FIG. In this case, the distances between the end nozzles 19 of the adjacent recording heads must be set to a distance P corresponding to one pixel.
The distance m from the end nozzle 19 to the end of the head in FIG.
Cannot secure a sufficient capacity of the ink reservoir 4,
There is a problem that printing defects easily occur.

In order to solve this problem, a so-called staggered arrangement as shown in FIG. 17 can be considered. FIG. 17 (A) is a view seen from the nozzle side, FIG. 17 (B)
FIG. 6 is a view seen from the ink supply port side. 16, those parts which are the same as those corresponding parts in FIG. 16 are designated by the same reference numerals, and a description thereof will be omitted. With this arrangement, in the recording head 18, the distance m from the end nozzle 19 to the head end can be sufficiently set, so that the above-described problem of defective printing of the end nozzle does not occur. However, even in this arrangement, the problem of impairing the linearity in the scanning direction is not solved when the interlace driving method is adopted.

The thermal ink jet system is required to improve not only the printing speed but also the printing resolution. In a thermal inkjet recording head in which nozzles are arranged in a straight line, the printing resolution corresponds to the nozzle array density and the heater array density. To improve the printing resolution, the nozzle and heater array densities It must be increased, and the head manufacturing technology becomes difficult.

[0022]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not impair the linearity in the main scanning direction even when the interlace drive system is adopted for high-speed printing. It is an object of the present invention to provide such an ink jet recording apparatus, and further to provide an ink jet recording apparatus which can cope with a high printing resolution without improving the manufacturing technique of the recording head.

[0023]

According to the present invention, a plurality of nozzles arranged on a straight line at equal intervals, an ink flow path corresponding to each nozzle, an ink droplet ejecting means, and ink are supplied to each ink flow path. In an inkjet recording apparatus having an ink jet recording head having a common liquid chamber and an ink supply port for controlling the ink droplet ejection means, and a control means for controlling the drive of the ink droplet ejecting means, the control means has a plurality of images corresponding to the nozzle arrangement width. The nozzles are controlled so as to perform printing in accordance with the print cycle, and in each print cycle, jump control is performed to sequentially jump by a predetermined interval so as to drive a certain range without overlapping, and the nozzle is The arrayed direction is perpendicular to the relative movement direction of the recording medium and the inkjet recording head. And it is characterized in that it is inclined by an angle determined by the number of interlaced and the number of drop ejection means for.

The control means for controlling the interlaced drive may be drive control so that the drive direction is folded back a plurality of times within a certain range until the drive timing of the adjacent ink droplet ejecting means.

A plurality of recording heads mounted so that the nozzle arrangement direction is inclined by a predetermined angle may be arranged in a direction perpendicular to the relative movement direction of the recording medium and the recording head.

The pitch of a plurality of nozzles arranged in a straight line in the recording head at equal intervals may be larger than the pitch of pixels determined by the printing resolution.
Further, a part of the voltage pulse for driving the ink droplet ejecting means driven at the next timing may be temporally overlapped with the voltage pulse for driving the ink droplet ejecting means.

[0027]

In order to increase the repetition frequency at which ink droplets are repeatedly ejected, when the interlace driving method in which a plurality of ink droplet ejecting means are skipped and driven at predetermined intervals is adopted, the ink droplet ejecting means corresponding to a certain nozzle is driven. There is a time delay from the time when the ink is ejected to the time when the ink droplet ejecting means corresponding to the adjacent nozzle is driven. According to the present invention, the arrangement direction of the nozzles is inclined by an amount corresponding to the print shift amount due to this time delay, so that the linearity disturbance in the direction perpendicular to the relative movement direction of the recording medium and the recording head ( Jagged) does not occur.

Further, even when a plurality of recording heads are connected in a direction perpendicular to the relative movement direction of the recording medium and the recording head to further improve the recording speed, the above driving method is applied, Since the head is inclined by a predetermined angle defined by the driving method, the linearity in the direction perpendicular to the relative movement direction of the recording medium and the recording head is not impaired.

Since the recording head is inclined with respect to the direction perpendicular to the relative movement direction of the recording medium and the recording head,
The arrangement pitch of the nozzles and the ink droplet ejecting means can be made larger than the pixel pitch determined by the printing density, and high printing resolution can be supported without improving the manufacturing technology of the recording head.

[0030]

EXAMPLE The thermal ink jet recording head used in the example has the same structure as the ink jet recording head described in Japanese Patent Application Laid-Open No. 5-155020 described in FIG. In this example, one print head
There are 64 nozzles used for printing at equal intervals on a straight line, and each of the 64 nozzles has a heater 7 in the corresponding flow path. No. 64 nozzles and heaters in order from the end. 1, NO. 2, ..., NO. A description will be given by numbering 64. It should be noted that the number of nozzles provided in one recording head is 64, which is an example, and the number of nozzles in the recording head in the present invention is not limited to 64.

Before describing the embodiments, a driving method which is a premise of the present invention will be described. 1 and 2 are explanatory diagrams of a heater driving order, FIG. 1 is an explanatory diagram of an example of an interlace driving method, and FIG. 2 is an explanatory diagram of a sequential driving method. Both are examples of driving 64 heaters.

In the sequential driving method shown in FIG. 2, the method shown in FIG.
As shown in No. 3, the driving order is the heater number order.
This is a method in which all the nozzles are driven by one scan in one printing cycle in the order of 1, 2, 3, ..., 64, and the adjacent heaters are sequentially driven. FIG. 2B shows a drive voltage waveform. When this driving method is used, when ink is re-supplied (refilled) into the flow path of the nozzle that ejected the ink droplets, the adjacent heaters are continuously driven so that the ink refills at approximately the same time. The ink negative pressure in the ink reservoir is locally increased, and the ink refill speed is reduced. For this reason, the sequential driving method has a problem that the printing repetition frequency F cannot be increased, as described above. In addition, since the pressure of the bubble generated on the heater propagates to the adjacent flow path and causes crosstalk, which causes unnecessary meniscus fluctuations in the nozzle section, it is necessary to wait for the meniscus fluctuations to subside sufficiently. The repetition frequency at which ink droplets can be ejected stably decreases.

An example of the interlace driving method is shown in FIG.
As shown in (A), 64 heaters are connected as shown in FIG. 1, 6, 11, ..., 56, 61, 2,
7, ..., 62, 3, ..., 63, 4, ..., 6
Drive in the order of 4, 5, ..., 60. In this interlace driving method, the NO. Focusing on one heater, NO. At the next timing after one heater is driven, the NO. 6 Heaters are driven. In this manner, the nozzles that are scattered are driven in one scan, and all the nozzles are driven by five scans in one printing cycle. FIG. 1B shows a drive voltage waveform.

Thus, the first heater No. The No. 1 heater is driven and is driven at the next timing. The spatial distance to 6 heaters (the number of heaters: 4 in this example) is M, and M + 1 is called the number of interlaces. In addition, No. One heater is driven and the adjacent NO. The number of heaters until the two heaters are driven is represented by L (12 in this example). This L
+1 is called the interlace level.

As can be seen from FIG. 1, M and L are the same regardless of which heater is focused. In such an interlace system, in order to make M and L the same regardless of which heater is focused, the number N of heaters covered by one interlace in one cycle (here, equal to the total number of nozzles). 64), it is necessary that the relation of N = (M + 1) × (L + 1) −1 holds. Therefore, when this relationship is established, the interlace level is determined by the total number of nozzles and the number of interlaces.

The tilted arrangement of the recording head will be described.
As described above, the relative movement direction of the recording medium and the recording head is called the sub-scanning direction, and the direction perpendicular to the sub-scanning direction is called the main scanning direction. In this case, the relative moving speed V between the recording medium and the recording head is calculated. As shown in FIG. 1, when the time until the next heater is driven is t, the time required to advance the distance for one pixel is the total number of nozzles × t,
If the pixel pitch is P, then V = P / 64t.

In the case of the sequential drive system, the relative movement amount of the recording medium and the recording head is one pixel in one printing cycle in which 64 nozzles are driven. Therefore, when the heads are arranged so that the nozzle arrangement direction and the sub-scanning direction are perpendicular to each other, the print pattern is inclined as described with reference to FIG. 14 (B) and 14 (C), the heater 7a corresponding to the nozzle 5a for printing the pixel 17a is driven, and then the heater corresponding to the nozzle 5b for printing the pixel 17b adjacent to the pixel 17a. Is driven after t, so that the pixel 17b is printed at a position separated from the pixel 17a by V × t = P × (1/64). Therefore,
By arranging the nozzle 5b adjacent to the nozzle 5a at a position shifted by P × (1/64), the pixel 17b is printed on the recording medium at a position on a straight line in the main scanning direction. become. In order to achieve this, it is sufficient to tilt the recording head by θ in advance.
Can be obtained by θ = tan ⁻¹ (1/64), which is about 0.895 °.

Also in the conventional interlace driving method, the relative movement amount of the recording medium and the recording head is one pixel in one printing cycle in which 64 nozzles are driven. Also in this driving method, it is possible to arrange the recording head while inclining it by the angle described above. However, even if the recording heads are arranged so as to be inclined, since the printing order is changed, when the straight line is printed, the linearity disorder cannot be avoided as described with reference to FIG.

The first embodiment of the present invention will be described with reference to the above-mentioned conventional example. The order of driving the nozzles is as shown in FIG.
It is the same as the order described in.

Now, consider arranging the head so that the nozzle array direction and the sub-scanning direction are perpendicular to each other. This will be described with reference to FIG. Since the heater corresponding to the nozzle adjacent to one nozzle a is driven after 13t,
The ink droplet ejected from the nozzle located at b1 adjacent to a is printed at the position of b2 which is separated by V × 13t = P × (13/64). Therefore, if the adjacent nozzle is arranged at the position b3 offset by 13P / 64, the print is made at the position b1 on the recording medium and is aligned with a in the main scanning direction. In order to realize this, it is sufficient to tilt the recording head in advance by θ as can be seen from FIG. 3, and this θ can be obtained by θ = tan ⁻¹ (13/64). It becomes .48 degrees.

FIG. 4 schematically shows a part of a dot array on a recording paper used as a recording medium when all 64 nozzles are ejected by the driving method shown in FIG.
For the sake of explanation, the case where the head is not intentionally tilted (the sub-scanning direction and the nozzle array direction remain vertical) is shown. The vertical and horizontal scales are different, and the dot size scale is also different from the actual scale.

As described above, according to the present invention, when one straight line is formed in the main scanning direction, ink ejected by, for example, 64 heaters driven during one printing cycle T (1 / F). Instead of printing one straight line with dots of drops, in the case of the driving sequence shown in FIG. 1, by using ink drops ejected from 64 nozzles during 13 printing cycles It prints a straight line. For example, focusing on the straight line 20a, the straight line formed in the first printing cycle is No. No. 1, 2, 3, 4, and 5 nozzles, and No. 6, 7, 8,
Straight line 2 printed in the first printing cycle with 9 and 10 nozzles
Printing is performed on the extension of 0a, and in No. 3 in the third printing cycle.
With the nozzles 11, 12, 13, 14, and 15, further printing is performed on the extension of the straight line 20a printed in the second printing cycle, and in the same manner, further printing is performed on the extension of the straight line 20a. Then, in the last 13th printing cycle, N
o. 61, 62, 63, 64 nozzles with the same straight line 20
Print on the extension of a and set 1 for all nozzles.
Two straight lines 20a will be printed.

Dots within a certain printing cycle that are not used for printing this straight line also change to other straight lines 20b, 20c, 20d, 2
Since it is used for printing 0e, ..., it is not wasted. Even though the printing is performed by the relative movement of the printing medium and the printing head once in the sub-scanning direction, the printing of (13-1) It only takes an extra period. If the repetition frequency F is 5 kHz, 12 cycles are 2.4 msec, which does not decrease the printing speed at all. Considering a case where printing is performed while the recording head moves by the carriage, in one carriage return cycle,
It can be said that the printing time only increases by 2.4 msec.

FIG. 5 shows a schematic diagram of a dot arrangement when solid printing is performed by this interlace driving method. The numbers given as line numbers in the figure are the lines perpendicular to the sub-scanning direction (lines in the main scanning direction).
, And each line has a length corresponding to the nozzle array width. The above figure shows a state in which printing is performed by the recording head having 64 nozzles, and the numbers above each 5 dots indicate the order of the printing cycle. To the (n + 12) th printing cycle. Therefore, the 5 dots below each number are the dots printed in the printing cycle. It should be noted that since each line has an interval of 1 dot, there is no gap, but the lines are shown with an intentionally spaced interval for easier understanding of the drawing. As can be seen from this figure, when printing n lines in the sub-scanning direction, it is necessary to repeat the printing cycle of n + 12.

When the number of nozzles in one head is tilted by the tilt angle θ calculated from the interlace level, in order to realize the pixel pitch P printed on the paper, the nozzle pitch P in the print head is realized. Is Pn = P / cos θ. When the pixel density is 300 spi, the pixel pitch P is about 84.5 μm, and the nozzle pitch Pn is 86.2 μm, which is wider than this.

FIG. 6 shows the driving order in the second embodiment of the present invention. This is one in which the scanning direction is folded back a plurality of times before the adjacent heaters are driven, and is called high-order interlaced driving. Here, the case is the case where the interlace level L + 1 = 11 and the number of skips M + 1 = 35. In this interlace, N = K = (L + 1) (M + 1) -1 holds with K = 6. This K is called an interlaced order. That is, the interlace shown in FIG. 1A can be said to be an interlace with an interlace order K of 1. Here, the number of heaters existing up to the heater driven at the next timing exists in two ways, 34 and 29. In the method described in FIG. 1, L + 1 = 1
3, which is L + 1 = 11 in this method, and the effect of avoiding the influence of meniscus vibration due to crosstalk in adjacent nozzles is not so different. However, the spatial distance (M + 1) of the heater driven at the next timing becomes larger in this method, and at a position where the bubble pressure generated in a certain heater is sufficiently attenuated, that is, in the state where there is no unnecessary meniscus vibration. , Can generate bubbles and eject ink drops. In this method, the angle θ at which the recording head is tilted is given by θ = tan ⁻¹ (11/64) and is about 9.75 °.

FIG. 7 is an explanatory diagram of a third embodiment of the heater driving method. In the driving method described in the first and second embodiments, the number of heaters driven at exactly the same timing was 1, but in this embodiment, FIG.
Two heaters are driven at the same time in the order shown in. That is, No. 1 to 32, the interlace level (L
+1) is 11, and the number of jumps (M + 1) is 3 K = 1
Apply the interlace driving method of. As shown in FIG. 7 (B), the same interlace drive method is used for No. 3 at the same timing. This is applied to the heaters 33 to 64. Even in this case, one interlace is 1
While the number N of heaters covered in a cycle is 32, the relationship of N × K = (M + 1) (L + 1) -1 is established. In this case, the angle θ of tilting the recording head is θ = tan ⁻¹ (11/32) = 18.97 °.

If this is expressed using the total number of nozzles N and the interlace level L + 1, then θ = tan ⁻¹ {(L + 1) / N}. In this case, the pixel pitch of 300 spi is 8
The nozzle pitch is about 89.4 μm with respect to 4.5 μm.

The total number of nozzles N and the number of jumps M
If expressed by +1 then θ = tan ⁻¹ {(N + 1) / N · (M + 1)}.

Next, a fourth embodiment in which the number of nozzles is increased to 264 in the ink jet recording head shown in FIG. 13 will be described. In this case, the number of heaters simultaneously ejecting is 1, and interlace of L + 1 = 53, M + 1 = 5, K = 1 is applied. FIG. 8A shows the driving order, and FIG. 8B shows the driving voltage waveform. In this embodiment, the angle at which the recording head is inclined with respect to the main scanning direction is given by θ = tan ⁻¹ (53/264), which is about 11.35 °.

Since the recording head of this embodiment has a large number of nozzles, the driving pulse is as shown in FIG.
When the heater to be driven at the next timing is driven after the driving of one heater is completely completed, the time T (one printing cycle) required to drive the same heater again becomes very long. For example, assuming that one voltage pulse length is 2.4 μs and the time to drive at the next timing is 0.25 μs, t = 2.65 μs, and 1
The print cycle is T = 264 × 2.65 = 699.6 μs, and the repetition frequency is about 1.4 kHz, which is far below the upper limit frequency.

In order to shorten T, it is sufficient to apply a plurality of the same interlace drive in one head and use a plurality of heaters simultaneously driven, as in the drive method of the embodiment shown in FIG. In this case, if the simultaneous drive heater is 4,
T becomes 1/4 and F becomes 4 times. However, an embodiment using another method will be described here.

As shown in FIG. 8B, the number of heaters driven at exactly the same timing is 1, but a certain voltage pulse and one portion of the voltage pulse driven at the next timing are superposed. Here, the time t from the application of a certain voltage pulse to the application of the next voltage pulse is 0.3 μm.
Let s. In this driving method, voltage pulses are applied to up to eight heaters at a certain time. In this way, T = 79.2 μs and the maximum repetition frequency is about 12.6 kHz.

Connecting a plurality of the above-mentioned recording heads,
A case of supporting a wide print width will be described.

FIG. 9 is a conceptual diagram of the head arrangement in the fifth embodiment of the ink jet recording apparatus of the present invention. In this embodiment, a plurality of heads are arranged so as to be connected to each other. In the figure, 22 is a nozzle group in each head,
Reference numeral 21 denotes a nozzle to be driven first (for example, No. 1 nozzle) in each nozzle group. The position of the nozzle (No. 1 nozzle) to be driven first is on the same side in each head, and the inclination angle θ of each nozzle group is the same. The nozzles are located in the same main scanning line direction. The interval between the nozzles at the opposite ends of the adjacent nozzle groups 22 is the pixel pitch P. The heater corresponding to each nozzle has the same No. 1 in each nozzle group. Things are driven at the same time. As the driving order, the interlaced driving method is adopted as described in each of the above-described embodiments.

FIG. 10 is a conceptual diagram of the head arrangement in the sixth embodiment of the ink jet recording apparatus of the present invention.
In this embodiment, as in the fifth embodiment, a plurality of heads are arranged so as to be connected to each other, but the nozzle 21 to be driven first is located on the opposite side of the nozzle group 22 of the adjacent recording head. There is. Also in this embodiment, since the inclination angle θ of each nozzle group is the same, the same No. The nozzles are located in the same main scanning line direction. The interval between the nozzles at the opposite ends of the adjacent nozzle groups 22 is the pixel pitch P. The heater corresponding to each nozzle has the same No. 1 in each nozzle group. Things are driven at the same time. As for the driving order, the interlaced driving method is adopted as in the fifth embodiment.

When a plurality of recording heads are arranged so as to be connected to each other as in the fifth and sixth embodiments, each recording head is located at the same position in the main scanning direction so as to print within the same recording print width. It was explained to be placed in.

However, with 264 nozzles, L + 1
= 53, M + 1 = 5, a recording head to which an interlaced drive is applied, and when the tilt angle is small such that the tilt angle θ is 11.35 °, all of the patterns shown in FIGS. It is difficult to arrange the position of the nozzle that is first driven by the head on one straight line in the main scanning direction.

FIG. 11 is an explanatory view of the arrangement of the recording heads in the modification of the fifth embodiment, which is an arrangement method suitable when the inclination angle is small. In the figure, 18a, 18b, 1
8c, 18d and 18e are recording heads, 21a, 21b,
Nos. 21c, 21d, and 21e are Nos. 1 nozzle, 22a, 2
2b, 22c, 22d, 22e are nozzle groups, 23a, 2
3b, 23c, 23d and 23e are joint parts.
As shown in FIG. In the so-called staggered arrangement in which the position of one nozzle is displaced by the distance d in the sub-scanning direction, it is tilted by an angle θ. With such an arrangement, it is possible to secure a sufficient distance from the nozzles at both ends of each recording head to the ends of the recording heads, and it is possible to sufficiently widen the ink reservoir, so that defective printing of the nozzles at both ends does not occur. Further, there is no need for high processing accuracy such that the distance from the nozzles at both ends to the head end is halved of the pixel pitch P. Of course, in this case, the recording head 1
The print start timings of the recording head 8a and the recording head 18b must be shifted by the time when the paper moves the distance d, but such printing control is very easy.

FIG. 12 is an explanatory view of the arrangement of recording heads in the modification of the sixth embodiment, which is an arrangement method suitable when the inclination angle is small. In the figure, parts similar to those in FIG. 11 are assigned the same reference numerals and explanations thereof are omitted. In order to supply the ink from the ink tank to the ink reservoir of the thermal inkjet recording head as described with reference to FIG. 13, it is necessary to install a joint portion for connecting to the outside at the ink supply port of the recording head. Often located directly above the supply port. Therefore, when the recording heads are connected as shown in FIG. 9, it is necessary to increase the distance d so that the joint portion 23c and the recording head 18b do not interfere with each other, and the entire print head in which a plurality of heads are connected together becomes large. . In FIG. 12, since the joint portions of the adjacent heads are attached in the directions opposite to each other, the distance d can be made smaller than that in the arrangement of FIG.
The size of the device can be reduced.

In addition to the interlaced order shown in the above-mentioned embodiment, L,
The values of M and K can be selected appropriately. At this time, if the numbers N, L, and M are selected so that the inclination angle θ of the nozzle row becomes large, the staggered arrangement shown in FIGS. It is possible to arrange the print heads further, and it is possible to further reduce the size of the print head. If the inclination angle θ is increased, the arrangement pitch of the nozzles and heaters can be made larger than the required pixel pitch, and the head manufacturing becomes easier. If L is selected so that a bubble is generated from an adjacent heater when ink is ejected from a certain nozzle and ink is being refilled from an ink reservoir to an ink flow path, the bubble pressure from the adjacent heater is refilled with ink. It becomes the power to promote the repetition frequency can be increased.

In the above-mentioned embodiment, the thermal ink jet system using the heater as the ink droplet ejecting means is taken as an example, but the electro-mechanical conversion element is used.
It is obvious that the present invention can be applied to other types of inkjet recording systems. Further, in the case of color printing, high speed printing can be performed by applying the above-mentioned method for each color.

[0063]

As is apparent from the above description, according to the present invention, since the nozzle rows are inclined by an angle determined by the interlace level and the number of nozzles, linearity in the main scanning direction is obtained even when interlaced driving is used. Is not compromised. Further, if the angle at which the nozzle rows are tilted is made larger, the pitch of the nozzles and heaters can be made larger than the required pixel pitch, so that high pixel density can be accommodated and high image quality printing can be realized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example of an interlace driving method.

FIG. 2 is an explanatory diagram of a sequential driving method.

FIG. 3 is an explanatory diagram of a tilted arrangement of a recording head.

FIG. 4 is an explanatory diagram schematically showing a part of a dot array in a printed state in the first embodiment of the present invention.

FIG. 5 is a schematic diagram of a dot arrangement when solid printing is performed in the first embodiment.

FIG. 6 is an explanatory diagram showing a drive sequence in a second embodiment of the inkjet recording apparatus of the present invention.

FIG. 7 is an explanatory diagram of a third embodiment of the inkjet recording apparatus of the present invention.

FIG. 8 is an explanatory diagram of a fourth embodiment of the inkjet recording apparatus of the present invention.

FIG. 9 is a conceptual diagram of head arrangement in a fifth embodiment of the inkjet recording apparatus of the present invention.

FIG. 10 is a conceptual diagram of a head arrangement in a sixth embodiment of the inkjet recording apparatus of the present invention.

FIG. 11 is an explanatory diagram of an arrangement of recording heads in a modified example of the fifth embodiment of the inkjet recording apparatus of the present invention.

FIG. 12 is an explanatory diagram of an arrangement of recording heads in a modified example of the sixth embodiment of the inkjet recording apparatus of the present invention.

13A and 13B show an example of a conventional thermal inkjet recording head. FIG. 13A is a cross-sectional view taken along a line perpendicular to the axial direction of the channel groove, and FIG. 13B is a plane taken along line BB in FIG. 13A. FIG. 1C is a front view seen from the nozzle side.

FIG. 14 is an explanatory diagram of a printing state of a sequential driving method.

FIG. 15 is an explanatory diagram of a printing state of an example of an interlace driving method.

FIG. 16 is a layout diagram of recording heads in a linear array.

FIG. 17 is a layout view of recording heads in a staggered arrangement.

[Explanation of symbols]

1 is a channel substrate, 2 is a heater substrate, 3 is a channel groove,
4 is an ink reservoir, 5, 5a, 5b, 5c, 5d, 5
e is a nozzle, 6 is an unetched portion, 7, 7a, 7b, 7
c, 7d and 7e are heaters, 8 is an insulating layer, 9 is a thick film resin layer, 10 is a first recess, 11 is a second recess, 12 is a partition, 13 is an ink drop, 14 is a recording medium, and 15 is Ink supply port, 16 is a drive pulse, 17a, 17b, 17c, 1
7d and 17e are pixels, 18 is a recording head, 19 is an end nozzle, 20a, 20b, 20c, 20d and 20e are printed straight lines, and 21a, 21b, 21c, 21d and 21e are No. 1 nozzle, 22a, 22b, 22c, 22d, 2
2e is a nozzle group, 23a, 23b, 23c, 23d, 2
3e is a joint part.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41J 3/10 106 L

Claims (1)

[Claims] 1. A plurality of nozzles arranged at equal intervals on a straight line, an ink flow path corresponding to each nozzle, an ink droplet ejecting means, and a common liquid chamber for supplying ink to each ink flow path and an ink. In an ink jet recording apparatus having an ink jet recording head having a supply port and a control means for controlling the drive of the ink droplet ejecting means, the control means controls to print an image corresponding to the nozzle array width in a plurality of printing cycles. At the same time, in each printing cycle, control is performed so as to perform interlaced driving in which predetermined intervals are sequentially skipped and a certain range is driven without overlapping, and the nozzles are arranged so that the direction in which they are arranged is the recording paper. And the number of ink droplet ejecting means to be driven in the direction perpendicular to the relative movement direction of the ink jet recording head and An inkjet recording device characterized by being tilted at an angle determined by the number of jumps.