JPH10323978A - Device and method for printing using a plurality of nozzle groups and recording medium containing program for operating them recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a printing image having high quality by using a print head having multiple dot forming elements and to perform interlaced printing even when a pitch of the dot forming elements is varied in the middle of arrangement thereof. SOLUTION: A print head 2 comprises a plurality of nozzle groups 2a, 2b which are provided at a predetermined distance (pn) therebetween in a sub-scanning direction. A plurality of nozzles of each of the nozzle groups 2a, 2b are arranged in the sub- scanning direction with a nozzle pitch (k). In a first printing method wherein each of the nozzle groups records different raster, the distance (pn) between groups is set to be a value different from the pitch (k) and the number N of all of the nozzles, the number M of nozzle groups, the number of times S of the scanning and the pitch (k) are determined such that each of N/(M.S) and k/M is a prime number with the other. Then, the sub-scanning with a constant pitch of N/S dot is executed. In a second printing method wherein each raster is recorded by the plurality of nozzle groups, the values N, M, S and k are determined such that each of N/(M.S) and k is a prime number with other, then the sub-scanning with a constant pitch of N/(M.S) dot is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing technique suitable for use in, for example, an ink-jet serial printer or a line printer, and more particularly, to a plurality of dots arranged at a group distance different from the dot forming element pitch. PRINTING APPARATUS AND PRINTING METHOD WITH PRINT HEAD HAVING FORMATION GROUPS
In addition, the present invention relates to a recording medium on which a program for performing the processing is recorded.

[0002]

2. Description of the Related Art As a printing apparatus according to the prior art, for example, a serial printer for printing one character at a time, a line printer for printing one line at a time, and the like are known. By driving a print head in which nozzles are formed in the main scanning direction and ejecting ink droplets from each nozzle, and conveying a print recording medium such as paper in a sub-scanning direction orthogonal to the main scanning direction, printing data is obtained. An appropriate print result is obtained. However, in such a conventional ink jet printer, since adjacent dot lines on a print recording medium are formed by ink droplets ejected from the same nozzle, there is a problem that variations in nozzle characteristics are conspicuous and print quality is low. is there.

[0003] For example, US Pat.
As described in No. 2, etc., the number n of driving nozzles and the nozzle pitch k are set so as to have a prime relationship with each other, and n
That the paper is fed with a fixed sub-scanning amount of dot pitch,
So-called constant pitch sub-scan interlaced printing has been proposed.

FIG. 1 is an explanatory diagram showing conventional interlaced printing. The print head 100 has N in the sub-scanning direction.
(N = 9 in the illustrated example) nozzles (# 1 to # 9) are arranged at a predetermined nozzle pitch k · D (k = 4 in the illustrated example). The sub-scan feed is performed with a constant feed amount L · D. In the example shown in FIG. 1, since all the nozzles are used as drive nozzles, the number of nozzles N and the number of drive nozzles n
Is equal to Here, D is the printing resolution, which is also called “dot pitch”. In the following, various parameters (k ・) defined by an integer multiple of the dot pitch D are used.
D, L.D, etc.) in some cases. For example, k is called “nozzle pitch” and L is called “feed amount”. When performing interlaced printing, the nozzle pitch k and the sub-scan feed amount L (= n) have a relatively prime relationship. For example, if k = 4 and the print resolution in the sub-scanning direction is 360 dpi, the nozzle pitch k
Is 4 dots (4/360 inches). Similarly, the paper feed amount, that is, the sub-scan feed amount L (= n) is 9 dots (9
/ 360 inches).

As shown in FIG. 1, each time the main scanning of the print head 100 is performed once, the sub-scanning at the L dot pitch is performed, so that adjacent dot lines are formed by different nozzles. For example, the dot line next to the dot line formed by nozzle # 7 in the first main scanning pass is # 5
The next dot line formed by the nozzle is # 3
The next dot line formed by the nozzle is #
It is formed by one nozzle. Therefore, by using interlace printing, variations in nozzle characteristics and the like are dispersed, so that a high-quality printed image can be obtained.

[0006]

In an ink jet printer of the interlaced printing system according to the prior art, on the assumption that a constant nozzle pitch k can be obtained, the nozzle pitch k and the number of driving nozzles n are relatively prime. , And the paper is fed at a constant pitch of n dots.

[0007] In recent years, there has been an increasing need for "multiple nozzles" in which a larger number of nozzles are formed in a print head than ever before due to demands for improvement in printing speed. However, it is difficult to stably form a large number of nozzles at a constant nozzle pitch, and there is a possibility that the nozzle pitch may fluctuate on the way or some of the nozzles may be defective. When a predetermined nozzle pitch cannot be obtained, even if interlaced printing according to the related art is performed, rasters are overlapped or unprintable rasters are generated, so that print quality is significantly reduced. Therefore, when forming a large number of nozzles in the print head, it is necessary to ensure a predetermined nozzle pitch,
Since the yield decreases, the manufacturing cost also increases. In other words, the conventional technology does not consider the recent demand for multi-nozzles at all and presupposes that a constant nozzle pitch can be obtained. It cannot be applied directly to the device.

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a high quality print image using a print head having a large number of dot forming elements. Another object of the present invention is to enable interlaced printing even when the pitch of the dot forming elements is different on the way.

[0009]

Means for Solving the Problems and Their Functions and Effects In order to achieve at least a part of the above or other objects,
The present invention provides a printing apparatus that performs printing by forming dots in a print area on a print recording medium. The printing apparatus includes a print head, a first scan driving unit that moves at least one of the print head and the print recording medium in a first scanning direction, and at least one of the print head and the print recording medium. A second scanning drive unit for moving in a second scanning direction orthogonal to the first scanning direction, and printing for forming dots on the print recording medium by driving the print head based on print image data A head drive unit. The print head includes N (N is an integer equal to or greater than 4) dot forming elements, and a minimum element pitch along the second scanning direction between two adjacent dot forming elements in the print head is k.・ D
(K is an integer, D is the dot pitch corresponding to the print resolution)
It is. Further, the N dot forming elements are N
Are divided into M (M and N / M are each an integer of 2 or more) dot forming element groups including / M dot forming elements, and the ith (i) Is 1
To (M-1)) and the (i + 1) -th dot forming element group are shifted in the second scanning direction by an inter-group pitch pg _i .D (pg _i is an integer different from k). . The second scan driver conveys at least one of the print head and the print recording medium in the second scan direction at a constant feed amount that is at least twice the dot pitch D. The first and second scanning drive units and the print head drive unit are configured so that the M dot forming element groups have the same dot formable position pattern, and the M dot forming element groups The print head and the print recording medium are driven such that dots can be formed at all dot positions in the print area by shifting the respective dot formable position patterns to each other.

Here, the term "dot forming element" means a mechanism or means for forming dots on a print recording medium. For example, an ink jet type in which ink droplets are ejected from nozzle holes by a piezoelectric vibrator or a heater. Actuators and the like correspond.

In the above-described printing apparatus, so-called interlace printing can be performed with a feed amount of 2 · D or more using M dot forming element groups, so that a printing head having a large number of dot forming elements can be used. High quality printing quality can be obtained.

According to one aspect of the present invention, adjacent dot forming element groups are separated by a gap along the second scanning direction, and the N / N of each dot forming element group is separated.
In each scan along the first scanning direction, the M dot forming elements form the same N / M dots that are substantially aligned in the second scanning direction with the minimum element pitch k.
-It can be formed with D.

In one embodiment, the same pattern of each of the M dot forming element groups is composed of a plurality of dot lines in the first scanning direction periodically arranged at a pitch of M dots. .

[0014] between the i-th and (i + 1) th dot forming element groups are separated by inter-group distance pn _i · D (pn _i is an integer), the value of pn _i from first to i-th pn ₁ to pN accumulated value of _{i (Σpn i)} the remainder obtained by dividing the dot forming element number group M (M-1) pieces of values. 1 to (M-
The values are set so as to take different values from each other in 1). Also,
The first scanning direction is repeated S times (S is a positive integer and M
(S is a factor of N) When forming the dot lines in the first scanning direction by scanning, the N, M, and N are set so that N / (M · S) and k / M are relatively prime. S and k are selected, and the second scanning drive unit conveys at least one of the print head and the print recording medium in the second scanning direction at a feed amount of N / S times the dot pitch D. . Here, the “inter-group distance” means a separation distance between adjacent dot forming element groups, and more specifically, the closest dot forming element among the dot forming elements of the adjacent dot forming element group. Mean pitch between.

As described above, when the N dot forming elements are grouped into the M dot forming element groups, and the inter-group distances pn _i .D of each dot forming element group are set as described above, A predetermined minimum element pitch k within the dot forming element group
D may be realized. In other words, a print head having a large number of dot forming elements can be easily obtained by integrating dot forming element groups in which dot forming elements are arranged at a predetermined minimum element pitch k · D.

Then, N, M, S, and k are selected so that N / (M · S) and k / M have a relatively prime relationship.
The second scanning drive unit conveys at least one of the print head and the print recording medium in the second scanning direction at a feed amount of N / S times the dot pitch D, so that adjacent dot lines are different from each other. It can be formed by dot forming elements.

[0017] The print head may be disposed by spaced respectively N / M pieces between the M number of dot forming element unit having a dot-forming element in the second scanning direction of the group distance pn _i · D And the N / M dot forming elements of each dot forming element unit may have a pitch equal to the minimum element pitch k · D in the second scanning direction. .

By using a plurality of dot forming element units in which the dot forming elements are arranged at the minimum element pitch k · D, it is possible to easily obtain a print head having a larger number of dot forming elements than before. That is, the yield is higher and the manufacturing cost is reduced when a plurality of dot forming element units are arranged and the print head is formed, rather than forming a large number of dot forming elements in the print head at one time.

Each of the dot forming element units includes an even-numbered dot forming element row in which a plurality of dot forming elements are formed in the second scanning direction at an element pitch of 2 k · D which is twice the minimum element pitch k · D. And the odd-numbered dot forming element rows may be formed so as to be separated from each other in the first scanning direction.

By arranging two dot forming element rows side by side in the first scanning direction, the minimum element pitch in each dot forming element row is twice as large as when one row is formed (=
2kD). Therefore, many dot forming elements can be easily formed in one dot forming element unit.

The first scanning drive section drives at least one of the print head and the print recording medium in the first scanning direction at a first scanning direction speed corresponding to the number of scans S. Is also good.

For example, when the number of scans S is set to 2 (S = 2), continuous dot lines in the first scanning direction are formed by two scans. Therefore, if the feed speed (first scanning direction speed) of the print head or print recording medium is the same as when S = 1, the printing speed is reduced by half. Therefore, by dynamically changing the feed speed of the print head or the print recording medium according to the number of scans S, it is possible to obtain high-quality print image quality without lowering print throughput. here,
The “first speed in the scanning direction according to the number of scans S” is
More specifically, it means the first scanning direction speed proportional to the number of scans S. It is preferable that the first scanning direction speed is proportional to the number of scans S, but the present invention is not limited to this.

In another aspect of the present invention, the same pattern of each of the M dot forming element groups is periodically arranged at a pitch of M dots on each dot line in the first scanning direction. Composed of a plurality of dots.

In an embodiment, the i-th and (i +
1) -th between groups between the dot forming element groups distance pn _i ·
D is (pn _i is an integer) apart, said pn _i is set to a different integer values and k. When forming the dot line in the first scanning direction by scanning the first scanning direction MS times (S is a positive integer and MS is a factor of N), The N, M, S, and k are selected so that (M · S) and k have a prime relationship with each other, and the second scanning drive unit sets the dot pitch D to N / (M · S) At least one of the print head and the print recording medium is transported in the second scanning direction by a double feed amount.

When the N dot forming elements are grouped into M dot forming element groups, and the inter-group distance pn _i .D of each dot forming element group is set as described above, each dot forming element group It is sufficient that a predetermined minimum element pitch kD is realized within the range. In other words, the predetermined minimum element pitch kD
By integrating the dot forming element group in which the dot forming elements are arranged, a print head having a large number of dot forming elements can be easily obtained.

Then, N, M, S, and k are selected so that N / (M · S) and k have a relatively prime relationship, and the second is selected.
Of the dot pitch D / N / (M ·
S) By transporting at least one of the print head and the print recording medium in the second scanning direction at a double feed amount, adjacent dot lines can be formed by different dot forming elements. Further, since each raster in the printing area is scanned by each dot forming element group, so-called overlap printing can be performed.

In the print head, the M dot formation is performed by suspending some of the plurality of dot formation elements arranged at the minimum element pitch k · D in the second scanning direction. An element group may be formed.

That is, a plurality of dot forming elements are formed at a predetermined minimum element pitch k · D, and a plurality of dot forming element groups can be obtained by not using some of the dot forming elements. In this case, the distance pn _i · D between groups is a multiple of the minimum element pitch k · D. Accordingly, for example, when a defect such as characteristic deterioration or omission occurs in a part of the dot forming element, the interlaced printing according to the present invention can be performed by suspending the dot forming element.

In another aspect of the printing apparatus, the N dot forming elements each include M dot forming elements.
It is divided into N blocks (BN is an integer equal to N / M), and adjacent blocks are separated from each other by a distance p between blocks.
b · D (pb is a positive integer not equal to k), and the M dot forming element groups are formed by corresponding dot forming elements in each block;
The M dot forming elements in each of the blocks are configured such that, in each scan along the first scanning direction, the same M dots that are arranged substantially in a line along the second scanning direction are the minimum elements. It can be formed with a pitch kD,
When scanning the first scanning direction MS times (S is a positive integer) to form a dot line in the first scanning direction, N / (MS) and ・ k · (M-1) ) + Pb} are selected so that N, M, S, k, and pb are coprime to each other, and the second scanning drive unit controls the dot pitch D
At least one of the print head and the print recording medium is conveyed in the second scanning direction at a feed amount of N / (M · S) times.

For example, when ten dot forming elements are divided into two blocks (N = 10, BN = 2), each block is composed of five dot forming elements (N / BN = 10/2 = 5). Therefore, in each block, there are five dot forming elements from the first dot forming element to the fifth dot forming element. Therefore, by grouping the corresponding dot forming elements in each block, such as the first dot forming elements, the second dot forming elements, and the third dot forming elements in each block. And five dot forming element groups. Thus, when the dot forming element group is configured,
Overlap printing by the interlace method can be performed.

In the print head, by suspending some of the plurality of dot forming elements arranged at the minimum element pitch k · D in the second scanning direction, the BN blocks are stopped. It may be formed.

The first scanning drive section drives at least one of the print head and the print recording medium in the first scanning direction at a first scanning direction speed corresponding to the number of scans M · S. You may make it.

Here, the M dot forming element groups scan the same dot line S times each. For example, when two dot forming element groups M1 and M2 are formed, each dot line in the print area is scanned by the first dot forming element group M1 and the second dot forming element group M2 is scanned. Is also scanned by Then, a continuous dot line in the first scanning direction is formed by each scan of each of the dot forming element groups M1 and M2. Therefore, S indicates the number of times each dot forming element group scans,
It can also be expressed as “the number of group scans S”.

Now, for example, when S is set to 2 (S
= 2) means that continuous dot lines in the first scanning direction are 2
It is formed by M scans. Therefore,
If the feed speed (first scanning direction speed) of the print head or print recording medium is the same as when S = 1, the printing speed is reduced by half. Therefore, by adaptively changing the feed speed of the print head according to the number of scans M · S, high-quality print image quality can be obtained without lowering print throughput.

Here, the "first scanning speed in accordance with the number of scans MS" means, more specifically, the first speed in the scanning direction which increases in accordance with the number of scans MS. Preferably, the first scanning direction speed is proportional to the number of scans M · S, but the present invention is not limited to this.

The present invention also provides a method for forming dots in a print area on a print recording medium while moving at least one of the print head and the print recording medium in a first scanning direction. The present invention is also directed to a printing method for performing printing using a printing apparatus that moves at least one of a print recording medium in a second scanning direction orthogonal to the first scanning direction. In this printing method, at least one of the print head and the print recording medium is transported in the second scanning direction at a constant feed amount that is at least twice the dot pitch D. Further, the printing is performed by shifting the dot-formable position patterns of the M dot-forming element groups so that the M dot-forming element groups have the same dot-formable position pattern. The print head and the print recording medium are driven so that dots can be formed at all dot positions in the area.

The present invention further comprises forming dots in a print area on the print recording medium while moving at least one of the print head and the print recording medium in the first scanning direction. The present invention is also directed to a recording medium that records a computer program for a computer that controls a printing apparatus that moves at least one of the recording media in a second scanning direction orthogonal to the first scanning direction. This computer program is a first program that causes the computer to operate so that one of the print head and the print recording medium is conveyed in the second scanning direction at a constant feed amount that is at least twice the dot pitch D. The printing is performed by shifting the dot formable position patterns of the M dot form element groups so that the M dot form element groups have the same dot formable position pattern. A second program for operating the computer so that dots can be formed at all dot positions in the area.

[0038]

Other Embodiments of the Invention The present invention includes the following other embodiments. A first aspect is an aspect as a program supply device that supplies, via a communication path, a computer program that causes a computer to realize the functions of each step or each part of the above-described invention. In such an embodiment, the above-described method and apparatus can be realized by placing the program on a server or the like on a network, downloading the necessary program to a computer via a communication path, and executing the program.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION

A. Basic Conditions of General Printing Method A-1.1 Basic Conditions of Printing Method Using One Nozzle Group FIG. 2 is an explanatory diagram showing basic conditions of a printing method using one nozzle group. is there. In FIG. 2A, solid circles including numbers indicate the positions in the sub-scanning direction of the four nozzles after each sub-scan feed. The numbers 1-4 in the circle are
It means the nozzle number.

FIG. 2B shows various parameters relating to this printing method. The parameters of the printing method include the nozzle pitch k [dot] and the number of used nozzles N
1 [number], the number of scans S, and the sub-scan feed amount L [dot] are included. The number of scans S [times] is the number of times that each raster is filled with dots in each of the main scans. In the example of FIG. 2, S = 1 because each raster is filled in one main scan.

In the example of FIG. 2, the nozzle pitch k is 3 dots, and the number N1 of nozzles used is four. The used nozzle number N1 is the number of nozzles actually used among the plurality of mounted nozzles. The number of scans S means that dots are formed intermittently every (s−1) dots in one main scan. Therefore,
The number of scans S is also equal to the number of nozzles used to record all dots on each raster.

The table of FIG. 2B shows, for each sub-scan feed, the sub-scan feed amount L, its cumulative value ΔL, and the nozzle offset F after each sub-scan feed. Here, the offset F refers to the periodic position of the first nozzle in which the sub-scan feed is not performed (the position every four dots in FIG. 2) as the reference position of the offset 0, and This value indicates how many dots the nozzle position is apart from the reference position in the sub-scanning direction. For example, FIG.
As shown in (1), the nozzle position moves by the sub-scan feed amount L (4 dots) in the sub-scan direction by the first sub-scan feed. On the other hand, the nozzle pitch k is 3 dots. Therefore, the nozzle offset F after the first sub-scan feed is 1
(See FIG. 2A). Similarly, the nozzle position after the second sub-scan feed has moved by ΔL = 8 dots from the initial position, and its offset F is 2. The nozzle position after the third sub-scan feed is ΔL =
It has moved 12 dots, and its offset F is zero. Since the nozzle offset F returns to 0 by the three sub-scan feeds, all the dots on the raster in the print area can be printed by repeating the three sub-scans as one cycle. .

As can be seen from the above example, the offset F is zero when the position of the nozzle is located at an integer multiple of the nozzle pitch k from the initial position. The offset F is given by the remainder (ΔL)% k obtained by dividing the total value ΔL of the sub-scan feed amount L by the nozzle pitch k. here,
“%” Is an operator indicating that the remainder of the division is taken.
If the initial position of the nozzle is considered to be a periodic position, the offset F can be considered to indicate the amount of phase shift from the initial position of the nozzle.

When the number of scans S is 1 and the sub-scan feed amount L is constant, it is necessary to satisfy the following condition C1 in order to avoid missing or overlapping raster lines to be recorded.

[Condition C1]: The sub-scan feed amount L is equal to the number of used nozzles N1, and the sub-scan feed amount L (= N1) and the nozzle pitch k are relatively prime.

The condition C1 can be understood by considering the following. In other words, if printing is performed without any raster omission, N1 × k rasters are printed during k scans. At this time, the nozzle position after the k times of sub-scan feed should be located at a position separated by N1 × k rasters from the initial nozzle position. In order to realize such a nozzle position, “the sub-scan feed amount L is equal to the number of used nozzles N1” may be set. Further, in order to prevent the recorded raster from being missing or overlapping, the value of each offset F in each of the k times of sub-scan feed is 0 to (k−
It is necessary to take different values in the range of 1). In order to realize such a value of the offset F, “the sub-scan feed amount L and the nozzle pitch k may be set to have a relatively prime relationship”. Here, “relatively prime relationship” means that two integers have no common divisor other than 1. By satisfying the above condition C1, it is possible to eliminate omissions and duplications in the recorded raster.

FIG. 3 is an explanatory diagram showing basic conditions of the printing method when the number of scans S is 2 or more. FIG.
The printing method shown in FIG. 2 is obtained by changing the number of scans S and the sub-scan feed amount L in the parameters of the printing method shown in FIG. As can be seen from FIG. 3A, the sub-scan feed amount L in the printing method of FIG. 3 is a constant value of 2 dots. In FIG. 3A, the positions of the nozzles after the odd-numbered sub-scan feeds are indicated by diamonds. As shown in the right end of FIG. 3A, the dot positions recorded after the odd-numbered sub-scan feeds are the dot positions recorded after the even-numbered sub-scan feeds and only one dot in the main scanning direction. It is out of alignment. Therefore, a plurality of dots on the same raster are recorded intermittently by two different nozzles. For example, the top raster in the print area is 1
After the fourth sub-scan feed, the third nozzle intermittently records every other dot, and after the fourth sub-scan feed, the first nozzle intermittently records every other dot. As described above, when the number of scans S is two or more, the same raster is printed by S different nozzles.

At the bottom of the table in FIG. 3B, the value of offset F after a plurality of sub-scans is shown. The offset F after each of the first to sixth sub-scan feeds includes a value in the range of 0 to 2 twice.

In general, when the number of scans S is 2 or more, one raster is printed by S scans, so that it can be considered that the effective number of nozzles is N1 / S. . Therefore, the sub-scan feed amount L may be set equal to the effective nozzle number N1 / S. That is, when the number of scans S is an integer of 2 or more, the above-described condition C1
Is rewritten as the following condition C1 ′.

[Condition C1 ']: The sub-scan feed amount L is equal to the effective nozzle number N1 / S, and the sub-scan feed amount L (= N
1 / S) and the nozzle pitch k have a prime relationship with each other.

In the condition C1 ', the sub-scan feed amount L
And the nozzle pitch k have a prime relationship with each other, the offset F after k times of sub-scan feeds is different from 0 to (k-1) as shown in FIG. I take the. The offset F after k × S sub-scan feeds is 0 to
Different values in the range of (k-1) are taken S times.
The number of scans S is selected so that N1 / S is an integer of 1 or more.

The above condition C1 'is such that the number of scans S is 1
Holds in the case of. Accordingly, the condition C1 ′ is a condition generally satisfied for a printing method in which the sub-scan feed is performed at a constant feed amount L using one set of nozzles regardless of the value of the number of scans S. However, when the number of scans S is 2 or more, a condition that the recording positions of the nozzles that record the same raster are shifted from each other in the main scanning direction is also necessary.

A-2. FIG. 4 is an explanatory diagram showing basic conditions of a first printing method using a plurality of nozzle groups. M nozzle groups NG
_{1 to} NG _M (M = 3 in FIG. 4) have the same nozzle arrangement, and have N1 nozzles arranged at a constant nozzle pitch k. Therefore, the total number N of nozzles of the _M nozzle groups NG _{1 to} NGM is equal to N1 · M.
Note that the distance between the i-th nozzle group NG _i and the (i + 1) -th nozzle group NG _{I + 1} (referred to as “inter-group distance”) is
It is a pn _i dots. The distance between the corresponding nozzles of the i-th nozzle group NG _i and the (i + 1) -th nozzle group NG _{i + 1} (referred to as “inter-group pitch”) is pg _i dots.

On the right side of FIG. 4, rasters recorded by each nozzle group are shown separately. As can be seen from the above, in the first printing method, each nozzle group prints a different raster, and the rasters printed by each nozzle group are periodically arranged at a pitch of M dots (first printing method).
How such a raster is recorded in the printing method will be described later in detail). That is, in the first printing method, the arrangement of the raster where each nozzle group executes printing is M
The same pattern periodically arranged at the dot pitch is shown, and by shifting the same pattern little by little for each nozzle group, all dots in the print area can be recorded.

In the printing method shown in FIG. 4, each nozzle group uses a plurality of nozzles arranged at a nozzle pitch k to record rasters arranged at a pitch of M dots. Feed amount N1 when one nozzle group is used
/ S times M. Further, this printing method is substantially equivalent to a printing method in which each nozzle group uses a nozzle having a nozzle pitch (k / M) to record a raster of one dot pitch, so that the effective number of nozzles N1 / S and k / M are determined. Set a disjoint relationship. At this time, the above condition C1 ′ can be rewritten as follows.

[Condition C2a]: The sub-scan feed amount L is equal to M times the effective nozzle number N1 / S (= N / S), and the effective nozzle number N1 / S (= N / (MS)). And (k / M)
And are coprime.

If the condition C2a is satisfied, each nozzle group can record rasters arranged at a pitch of M dots. The nozzle pitch k and the number M of nozzle groups are selected such that (k / M) is an integer of 1 or more. On the other hand, as shown on the right side of FIG. 4, in order that the raster groups recorded by the respective nozzle groups are slightly shifted from each other, the following condition C2b may be satisfied.

[Condition C2b]: (Σpn _i )% M (M
-1) values take different values from 1 to (M-1).

Here, (Σpn _i ) is the inter-group distance pn ₁ from the first to the i-th (i is an integer of 1 to (M−1)).
Shows the accumulated value to PN _i, operator "%" denotes an operation of taking a remainder of the division. If the inter-group distance pn _i satisfies the above condition C2b, the (M-1) inter-group distances pn _{1 to} pn _M-1 may have the same value.

In the condition C2b, the inter-group distance pn _i
The following condition C2c using the inter-group pitch pg _i instead of is also satisfied.

[Condition C2c]: (Σpg _i )% M (M
-1) values take different values from 1 to (M-1).

Since the inter-group pitch pg _i can be smaller than the distance k · (N1-1) between the nozzles at both ends of one nozzle group, the condition C2c is more general than the condition C2b. Condition. That is, the condition C2b is a condition that is satisfied in a specific case that satisfies the more general condition C2c.

FIG. 5 is an explanatory diagram showing the basic conditions of the second printing method using a plurality of nozzle groups. In this printing method, each nozzle group prints on all rasters, and each nozzle group prints one of all the dots of one raster.
/ M recording. In other words, the dots recorded by one nozzle group are arranged at a pitch of M dots on each raster (how such dots are recorded will be described later in detail). . In such a printing method, since each nozzle group performs printing on all rasters, the following conditions, which are the same as the printing method using only one nozzle group shown in FIG. .

[Condition C3a]: The sub-scan feed amount L is equal to the effective nozzle number N1 / S (= N / (MS)), and
Sub-scan feed amount L (= N / (MS)) and nozzle pitch k
And are coprime.

As for the inter-group distance pn _i , the following condition C3b which is milder than the above condition C2b may be satisfied.

[0066] [Condition C3b]: intergroup distance pn _i takes a value different from the nozzle pitch k.

Similarly, the inter-group pitch pg _i may satisfy the following condition C3c, which is milder than the above condition C2c.

[Condition C3c]: The inter-group pitch pg _i takes a value different from the nozzle pitch k.

In the second printing method shown in FIG. 5, each raster is printed by M nozzle groups, and each nozzle group prints on one raster by scanning S times. Since each raster is recorded by scanning MS times, (MS) is referred to as “the number of raster scans”. Further, the number of scans S of one nozzle group is also referred to as “group scan number”.

In the example of FIG. 5, the column direction (vertical direction)
Dot line is recorded by one nozzle group,
As in the examples of FIGS. 17 and 18 described later, it is also possible to print dot lines in the column direction with different nozzle groups. Also in this case, the dots recorded by each nozzle group are arranged at a pitch of M dots on each raster, and the positions of the dots recorded by that nozzle group are shifted in the row direction for each raster. I take the. That is, the second
In the printing method, the arrangement of dots that each nozzle group executes printing shows the same pattern that is periodically arranged at a pitch of M dots on each raster, and this same pattern is assigned to each nozzle group. By shifting each dot a little, every dot in the print area can be recorded.

In this specification, the term “dot line” is defined by a line (that is, a raster) formed by dots arranged in a row direction (horizontal direction) and a dot formed by dots arranged in a column direction (vertical direction). It is also used as a generic term for lines.

In the first printing method described above, each nozzle group performs printing of all dots on a raster array arranged at a pitch of M dots, while in the second printing method, each nozzle group prints all the rasters. Printing is performed on the above, but printing of dots arranged at a pitch of M dots is performed on each raster. However, the first and second printing methods are described as follows. "The printing positions of a plurality of nozzle groups form the same printing position pattern, and the printing position patterns of the plurality of nozzle groups are shifted from each other. All dot positions within the area can be recorded. " Here, the “same recording position pattern” is a pattern composed of “rasters arranged at a pitch of M dots” in the first printing method, and “a M dots on each raster” in the second printing method. Of dots arranged at the same pitch.

B. Embodiment of first printing method B-1. First Embodiment of First Printing Method FIGS. 6 to 8 show an inkjet printer 1 as a printing apparatus according to a first embodiment of the first printing method of the present invention.
Is shown. FIG. 6 is an explanatory diagram showing the overall configuration of the inkjet printer 1. As will be described later, the inkjet printer 1 includes a print head 2, a main scanning drive unit 3, a sub-scanning drive unit 4, Unit control unit 5
, A data storage unit 6, a print head driving unit 7, and a main scanning speed management table 8. In the present embodiment, the “first scanning direction” is expressed as a main scanning direction (horizontal direction in the figure), and the “second scanning direction” is expressed as a sub-scanning direction (vertical direction in the figure). I do.

The print head 2 has a “dot forming element group”
The first nozzle group 2a and the second nozzle group 2b are arranged at a predetermined inter-group distance pn · D in the sub-scanning direction. This inter-group distance pn · D means a distance corresponding to pn times the dot pitch D in the printing resolution. When the number M of nozzle groups is 2, as in the case of FIG. 6, a natural number (ie, an odd number) that is not a multiple of 2 is selected as the inter-group distance pn.

As shown in FIG. 7, each of the nozzle groups 2a and 2b is composed of an actuator unit 10 as a "dot forming element unit", and each of the nozzle groups 2a and 2b has N1 nozzles (in the illustrated example, each of them). N1 =
The nozzle is provided as the “dot forming element” of 5). In other words, N (N = N1 + N1 = 10) nozzles are grouped into two nozzle groups 2a and 2b. Here, the number N of nozzles is an integer of 4 or more.

In each of the nozzle groups 2a and 2b, each nozzle has a nozzle pitch k ··
D is provided in the sub-scanning direction. Here, the nozzle pitch k · D is a distance corresponding to k times the dot pitch D, and k is a multiple of the number M of nozzle groups.

The main scanning drive unit 3 as a “first scanning driving unit” moves the print head 2 in the main scanning direction (left and right in FIG. Direction). Also, a “second scanning drive unit”
The sub-scanning driving unit 4 as a print recording medium SP in a sub-scanning direction (vertical direction in FIG. 6) orthogonal to the main scanning direction.
Is driven so as to convey.

The drive controller 5 moves the print head 2 in the main scanning direction by controlling the driving amount and the driving timing of the main scanning driver. Further, the drive unit control unit 5 sets the transport amount of the print recording medium SP by the sub-scanning drive unit 4 to a value (NDD / S) that is N / S times the dot pitch D.
Thus, a constant-pitch medium transport operation mode is realized, and control is performed so that dots are formed by a so-called interlace printing method.

Here, in order to form adjacent dot lines by different nozzles, the above-described parameters N,
M, S, and k must satisfy the condition that "N / (MS) and k / M are relatively prime". Nozzle group number M
Is the factor of the number N of nozzles, and the nozzle pitch k is a multiple of the number M of nozzle groups. Therefore, both N / (M · S) and k / M are integers. It is. In the example shown in FIG. 6, if the number of scans S = 1, N /
(MS) = 10 / (2.1) = 5, and k / M = 4
Since / 2 = 2, N / (MS) and k / M have a relatively prime relationship. These parameters satisfy the above-described conditions C2a, C2b, and C2c.

The data storage section 6 comprises a memory for storing print image data, and a data block area (not shown) is formed in the memory. Then, the print head drive unit 7 energizes the print head 2 based on the print image data stored in the data storage unit 6, so that the first
The ink is ejected from the predetermined nozzles of the nozzle group 2a and the second nozzle group 2b onto the print recording medium SP, whereby a print result based on the print data is obtained.

The main scanning speed management table 8 is for dynamically controlling the main scanning speed VS as the “first scanning direction speed” according to the number of scans S in the main scanning direction. That is, the main scanning speed VS, which is the moving speed of the print head 2, is stored in the main scanning speed management table 8 in association with each printing mode having a different number of scans S. Here, when the number of scans S = 1, that is, assuming that the main scanning speed VS1 when forming a dot line in the main scanning direction by one scan is the reference speed, the number of scans S
The main scanning speed VS is set to increase in accordance with the magnification of. That is, the main scanning speed VS2 when S = 2 is set to twice the reference speed VS1, and the main scanning speed VS3 when S = 3 is set to three times the reference speed VS1. However, the present invention is not limited to this. For example, S = 2
In this case, the main scanning speed VS2 may be set to 1.5 times the reference speed VS1.

Next, a specific example of the print head 2 will be described with reference to FIGS. FIG. 7 is a plan view of the print head 2. A plurality of print heads 2 (two in FIG. 7)
The actuator units 10 are separated from each other by a group distance pn · D. Each actuator unit 10 is formed with a plurality of nozzle actuators.

FIG. 8 is a sectional view of each nozzle actuator. An ink chamber 12, an ink supply port 13, and a pressure chamber 14 are formed in the flow path forming plate 11. Ink in an external ink tank (not shown) is supplied from an ink chamber 12 to a pressure chamber 14 via an ink supply port 13. A diaphragm 15 is provided on the back side of the flow path forming plate 11, and an island portion 16 is formed on the diaphragm 15. The piezoelectric vibrator 17 is provided such that one end of the piezoelectric vibrator 17 is in contact with the island portion 16. The piezoelectric vibrator 17 is formed, for example, to contract when charged and to expand when discharged.

The nozzle plate 20 has a plurality of nozzle holes 2 corresponding to the respective nozzle actuators.
1 is formed. Each nozzle hole 21 is formed with a nozzle pitch kD for each actuator unit 10. As shown in FIG. 7, this nozzle plate 2
By providing 0 on the actuator unit 10, the print head 2 is formed. In addition, not limited to this,
For example, it is also possible to use a micro-heater or the like so that ink droplets are ejected by bubbles generated by heating the heater.

Since each nozzle actuator has a complicated structure including an ink flow path such as a pressure chamber 14 and a piezoelectric vibrator 17, a large number of nozzle actuators can be stably formed in a single actuator unit 10. Is difficult.
However, in the present embodiment, since the print head 2 is configured by disposing the plurality of actuator units 10, the print head 2 having a large number of nozzle actuators can be easily obtained.

Next, the operation of the present embodiment will be described with reference to FIGS. As described above, in the present embodiment, the number of nozzle groups M = 2, the number of nozzles N = 10, the nozzle pitch k = 4, the distance between groups pn = 5, the number of scans S = 1, and the sub-scan feed amount L = N is there.

In each main scanning pass, each nozzle group 2a,
Each nozzle 2b can form a dot by discharging an ink droplet. Since a constant pitch sub-scan of N dot pitch is performed for each main scan, dot lines are densely formed in the sub-scan direction until the relative position between the print head 2 and the print recording medium SP reaches a predetermined positional relationship. Can not do. That is, the position of the nozzle # B3 in the third main scanning pass P3 is the start point of the print area.

FIG. 10 is an explanatory diagram showing an enlarged dot formation situation for 12 dot lines from the start point of the print area. As shown in FIG. 10, in the present embodiment, since the number of scans S = 1, each dot line in the main scanning direction is formed by one main scan. Further, each dot line adjacent in the sub-scanning direction is formed by a different nozzle.

In the present embodiment configured as described above,
The following effects are obtained.

First, a plurality of nozzles (nozzle actuators) are grouped into a plurality of nozzle groups 2a and 2b, and the nozzle groups 2a and 2b are arranged at a distance pnD between the groups different from the nozzle pitch k. Print head 2
Is formed, the print head 2 having a large number of nozzles can be easily obtained. That is, each nozzle group 2a,
Since it is sufficient to secure the nozzle pitch k only within 2b,
Yield is improved and manufacturing costs are reduced.

Second, the number of used nozzles N, the number of nozzle groups M, the number of scans S, and the nozzle pitch k are selected so that N / (MS) and k / M have a prime relationship with each other. Since the sub-scanning is performed at a constant pitch of N / S times the pitch D, so-called interlace printing can be realized by the print heads 2 having partially different nozzle pitches. Accordingly, adjacent dot lines can be formed by different nozzles, and high-quality printing can be performed by dispersing variations in nozzle characteristics.

Third, since the print head 2 is formed by arranging in the sub-scanning direction a plurality of actuator units 10 in each of which a plurality of nozzle actuators are arranged at a nozzle pitch k in the sub-scanning direction. Print head can be stably obtained. Further, print heads 2 having various numbers of nozzles can be obtained only by changing the number of actuator units 10 to be used.

B-2. Second Embodiment of First Printing Method Next, a second embodiment of the first printing method of the present invention will be described with reference to FIGS. In the following embodiments, the same components as those in the first embodiment of the above-described first printing method are denoted by the same reference numerals, and description thereof will be omitted. This embodiment is characterized in that all nozzles are divided into three nozzle groups.

That is, the print head 31 of the present embodiment is
Each of the nozzle groups includes a first nozzle group 31a, a second nozzle group 31b, and a third nozzle group 31c in which three nozzles are arranged at a nozzle pitch k. Further, the first nozzle group 31a and the second nozzle group 31b are separated from each other by a first group distance p.
The second nozzle group 31b and the third nozzle group 31c are separated by a second inter-group distance pn2 · D. The parameters of the present embodiment are as follows: the number of nozzles used N = 9, the number of nozzle groups M = 3, the number of scans S
= 1, nozzle pitch k = 6, first group distance pn1 =
8, the second group distance pn2 = 5. Therefore, N /
(MS) = 9 / (3.1) = 3, k / M = 6/3 = 2
Therefore, they are disjoint.

Here, when the inter-group distances pni differ among the nozzle groups as in the present embodiment, it can be determined based on the following equation (1).

Pn1 = (pn2 + α · M) (Equation 1) where α is an integer, ie, the distance between one group is pn1 and the distance between the other groups is pn2
And a multiple of M. In the case of the present embodiment, the first inter-group distance pn1 is pn1 = (pn2 + α · M) =
(5 + 1 · 3) = 8 is determined. In general, the above-mentioned condition C2b “(Σpn _i )% M (M−
1) values take different values from 1 to (M−1) ”.

In the case of the present embodiment, as shown in FIG.
The position of the nozzle # B2 in the third main scanning pass P3 is the starting point of the print area, from which dot lines can be densely formed in the sub-scanning direction. FIG. 12 is an explanatory diagram showing an enlarged dot formation state for 15 dot lines from the start point of the print area. As shown in FIG. 12, dot lines adjacent in the sub-scanning direction are formed by different nozzles.

Therefore, also in the present embodiment configured as described above, it is possible to obtain the same effect as that of the first embodiment of the first printing method described above.

B-3. Third Embodiment of First Printing Method Next, a third embodiment of the first printing method of the present invention will be described with reference to FIGS. A feature of the present embodiment is that a dot line in the main scanning direction is formed by scanning twice in the main scanning direction.

That is, the print head 4 according to the present embodiment
1 includes a first nozzle group 41a and a second nozzle group 41b arranged in the sub-scanning direction via an inter-group distance pn · D, and the nozzle groups 41a and 41b are respectively arranged in the sub-scanning direction. It is formed by arranging six nozzles at a nozzle pitch kD. The parameters of the present embodiment include the number of nozzles used N = 12, the number of nozzle groups M = 2, the number of scans S = 2, the nozzle pitch k = 4, and the inter-group distance pn.
= 5. Therefore, N / (M · S) = 12 / (2 ·
2) = 3 and k / M = 4/2 = 2, N / (M ·
S) and k / M are relatively prime.

As shown in FIG. 13, in the present embodiment,
The print area starts from the position of nozzle # B5 in the fifth main scan pass P5, and each dot line is formed by two main scans. FIG. 14 is an explanatory diagram showing an enlarged dot formation situation for 12 dot lines from the start point of the print area.

As shown in FIG. 14, also in the present embodiment,
Dot lines adjacent in the sub-scanning direction are formed by different nozzles. In addition, in this embodiment, since the number of scans in the main scanning direction is set to S = 2, a dot line continuous in the main scanning direction is formed by two main scans. That is, dots adjacent to each dot line in the main scanning direction are formed by different nozzles. It is printed by so-called overlap.

In other words, since the same raster is scanned twice, not only the overlap shown in FIG. 14 but also other types of overlap printing can be performed. In other words, a continuous dot line is formed in the first main scan, and new dots are further superimposed on the already formed dots in the next main scan, so that further multi-tone printing can be performed. .

B-4. Fourth Embodiment of First Printing Method A fourth embodiment of the first printing method of the present invention will be described with reference to FIG. The feature of this embodiment is that a plurality of actuator units are shifted by a predetermined distance in the main scanning direction.

As shown in FIG. 15, the print head according to the present embodiment is composed of a plurality of actuator units 51. Each actuator unit 51 includes:
Each is formed by arranging a plurality of nozzles at a predetermined nozzle pitch k in the sub-scanning direction.

The actuator units 51 are arranged so as to be shifted in the sub-scanning direction so that the distance between the nozzles closest to each other becomes a predetermined group distance pn · D. A predetermined distance WL in the scanning direction
Only separated.

In the present embodiment configured as described above,
It is possible to obtain the same number of nozzle groups as the number of the actuator units 51, and it is possible to obtain the same effect as in the first embodiment. Further, in this embodiment, since the actuator unit 51 is shifted in the main scanning direction so as to be able to overlap in the sub-scanning direction, the length of the print head in the sub-scanning direction can be reduced.

B-5. Fifth Embodiment of First Printing Method Next, a fifth printing method of the first printing method of the present invention will be described with reference to FIG.
An embodiment will be described. A feature of the present embodiment is that a print head is formed by arranging actuator units having even-numbered nozzle rows and odd-numbered nozzle rows in the sub-scanning direction.

That is, the print head 61 according to the present embodiment
Is provided with, for example, four nozzle arrays 62 spaced apart in the main scanning direction. Each of these nozzle arrays 62
Are in charge of predetermined ink colors, for example, black, cyan, magenta, yellow, etc.
From each nozzle array 62, ink droplets of the same color are respectively ejected.

Each nozzle array 62 is configured by arranging a plurality of actuator units 63 in the sub-scanning direction. Each of the actuator units 63 includes an even-numbered nozzle array 63a and an odd-numbered nozzle array 63 each having a plurality of nozzles arranged at a nozzle pitch of 2 kD in the sub-scanning direction.
b in the main scanning direction. Further, the separation distance between the nozzles closest to each other among the nozzles of the actuator units 63 adjacent to each other is set to be a predetermined group distance pn · D.

In the present embodiment having the above-described structure, the same effects as those of the first embodiment can be obtained. In addition, in the present embodiment, since the nozzle pitch is large, a high-density print head can be easily manufactured with multiple nozzles, and the manufacturing cost can be reduced.

As can be seen from the example of FIG. 16, the N1 nozzles included in each nozzle group do not necessarily have to be aligned in a straight line, but are arranged in a line substantially in the sub-scanning direction.
It is only necessary that one dot can be formed at a constant pitch k.

It should be noted that those skilled in the art can appropriately make changes, additions, modifications, deletions, and the like to the above-described embodiments of the first printing method without departing from the scope of the present invention. For example, in each embodiment, the case where dots are formed from the main scanning direction as the first scanning direction has been described. However, the present invention is not limited to this, and printing is performed from the sub-scanning direction as the second scanning direction. You can also.

In each embodiment of the first printing method, a serial printer has been described as an example. However, the present invention can also be applied to a line printer and the like, and can also be applied to a facsimile machine and a copying machine. Further, the present invention can be applied to a composite printing apparatus in which various functions such as a facsimile function are combined.

As is clear from the above description, according to the first printing method of the present invention, the distance pn between the dot forming element groups and the dot forming element group is determined by the dot distance within the dot forming element group. Since it is different from the minimum element pitch k of the forming element, a print head having a large number of dot forming elements can be easily formed. Furthermore, N / (MS) and k /
Each parameter N, M, S,
Since k is selected and the print recording medium is conveyed at a constant pitch of N / S times the dot pitch D, even if the element pitch of the dot forming element is different in a part of the print head due to the inter-group distance pn, the so-called “k” is used. Interlaced printing can be performed.

C. Embodiment of second printing method C-1. First Embodiment of Second Printing Method As the hardware configuration of the second printing method, it is possible to use substantially the same hardware configuration as that of the first printing method shown in FIGS. it can. FIG. 17 is an explanatory diagram showing a state of a printing process according to the first embodiment of the second printing method.

The print head 71 has a first nozzle group 71a and a second nozzle group 7 as a "dot forming element group".
1b are arranged at a predetermined distance pn · D between groups in the sub-scanning direction. The group distance pn · D means a distance corresponding to pn times the dot pitch D, and pn
Is selected as a positive integer other than k.

Each of the nozzle groups 71a and 71b has N
One (N1 = 5 in the illustrated example) nozzles are provided as “dot forming elements”. In other words, N (N = N1)
+ N1 = 10) has two nozzle groups 71a, 7
1b.

Here, the number of nozzles N is an integer of 4 or more, and the number of nozzles N and the number of nozzle groups M (an integer of 2 or more) are unequal.

The print recording medium SP by the sub-scanning drive unit 4
Is the value (ND / (MS)) times N / (MS) times the dot pitch D. This constant-pitch medium transport operation mode realizes a so-called interlace printing method.

Here, in order to form adjacent dots by different nozzles, the above parameters N, M,
S, k is "N / (MS) and k are relatively prime"
It is necessary to satisfy the condition. The number of raster scans M · S, which is the product of the number of nozzle groups M and the number of group scans S, is a factor of the number of nozzles N, and the nozzle pitch k is a positive integer. k are both integers.
In the example shown in FIG. 17, when the number of group scans S = 1,
N / (MS) = 10 / (2.1) = 5, and k = 4
Therefore, they are relatively prime. Here, the number of group scans S means the number of times each nozzle group performs a scan, and the number of raster scans M · S means one dot line (in the main scanning direction) by each scan by each nozzle group. That is, the number of scans for forming one raster). These parameters satisfy the above-described conditions C3a, C3b, and C3c.

The print head drive unit 7 (FIG. 6) energizes the print head 71 based on the print image data stored in the data storage unit 6, thereby causing the first nozzle group 71a and the second nozzle group 71b. The ink is ejected from the predetermined nozzle to the print recording medium SP, thereby obtaining a print result based on the print data.

In the second printing method, the main scanning speed management table 8 (FIG. 2) sets the main scanning speed VS as the “first scanning speed” according to the number of raster scans M · S in the main scanning direction. Control dynamically. That is, the main scanning speed management table 8 stores the main scanning speed VS, which is the moving speed of the print head 71, in association with each printing mode having a different number of scans M · S. Here, if the number of group scans S = 1, that is, if the main scanning speed VS1 in the case where one nozzle group forms dot lines in the main scanning direction by one scan is the reference speed, the number of group scans S The main scanning speed VS is set to increase according to the magnification. That is, the main scanning speed VS when S = 2
2 is set to twice the reference speed VS1, and the main scanning speed VS3 when S = 3 is set to three times the reference speed VS1. However, the present invention is not limited to this. For example,
The main scanning speed VS2 when S = 2 may be set to 1.5 times the reference speed VS1. The main scanning speed is preferably increased in proportion to the number M of nozzle groups, but may be increased in proportion to only the number S of group scans without depending on the number M of nozzle groups.

As described above, in the embodiment shown in FIG. 17, the number of nozzle groups M = 2, the number of nozzles N = 10, the nozzle pitch k = 4, the distance between groups pn = 5, the number of group scans S = 1,
The sub scanning amount is N / (M · S) (= 10/2 = 5).

In each main scanning pass, each nozzle group 71
The nozzles a and 71b can form dots by ejecting ink droplets. Since a constant pitch sub-scan of N / (M · S) dot pitch is performed for each main scan, the dot line is sub-scanned until the relative position between the print head 71 and the print recording medium SP reaches a predetermined positional relationship. It cannot be formed densely in the direction. That is, the position of nozzle # A4 in the first main scanning pass P1 is the start point of the print area. Further, each of the nozzle groups 71a and 71b is
In order to execute interlaced printing, each raster in the printing area is formed by each of the nozzle groups 71a and 71b. That is, in the second printing method of the present invention, so-called overlap printing is performed, so that each raster in the printing area is formed using both the nozzle groups 71a and 71b.

FIG. 18 is an explanatory diagram showing an enlarged dot formation state for 10 dot lines from the start point of the print area. As shown in FIG. 18, in the present embodiment, since the number of group scans S = 1, each dot line in the main scanning direction is formed by one main scan by each of the nozzle groups 71a and 71b. .

That is, each dot line corresponds to the nozzle group 71a.
(Dots) and dots (o) formed by the nozzle group 71b. Further, dot lines adjacent in the sub-scanning direction are formed by different nozzles.

In the present embodiment configured as described above,
The following effects are obtained.

First, a plurality of nozzles (nozzle actuators) are grouped into a plurality of nozzle groups 71a and 71b, and the nozzle groups 71a and 71b are arranged with a spacing pn different from the nozzle pitch k. , The print head 71 having a large number of nozzles can be easily obtained. That is, it is sufficient to secure the nozzle pitch k only in each of the nozzle groups 71a and 71b, so that the yield is improved and the manufacturing cost is reduced.

Second, the number of used nozzles N, the number of nozzle groups M, the number of group scans S, and the nozzle pitch k are selected so that N / (M · S) and k have a prime relationship with each other, and the printing resolution is selected. In the configuration, the constant pitch sub-scanning of N / (M · S) times the dot pitch D is performed, so that a so-called interlaced printing can be realized by the print head 71 having a partially different nozzle pitch. Accordingly, adjacent dot lines can be formed by different nozzles, and high-quality printing can be performed by dispersing variations in nozzle characteristics.

Third, in the present embodiment, each raster in the print area can be scanned by each of the nozzle groups 71a and 71b, and so-called overlap printing can be performed.

Fourth, since a plurality of nozzle actuators are arranged in the sub-scanning direction with a plurality of actuator units arranged in the sub-scanning direction at a nozzle pitch k, the print head 71 is formed. A print head can be stably obtained. Further, the print head 71 having various numbers of nozzles can be obtained only by changing the number of actuator units to be used.

In particular, the inter-group distance pn may be any positive integer other than the nozzle pitch k, and no other restrictions are imposed. Therefore, it is easy to obtain a multi-nozzle print head 71 by integrating actuator units. Can be.

In the present embodiment, each nozzle 71
Since the positions of the dots formed by a and 71b are shifted by one dot in the main scanning direction for each dot line in the sub-scanning direction, the overlap is performed, so that the dots can be formed in a so-called checkerboard pattern. However, the present invention is not limited to this, and it is also possible to adopt a configuration in which the dot formation positions of the respective nozzle groups are aligned in the sub-scanning direction, as in a second embodiment described later.

C-2. Second Embodiment of Second Printing Method Next, a second embodiment of the second printing method of the present invention will be described with reference to FIGS. This embodiment is characterized in that all nozzles are divided into three nozzle groups.

That is, the print head 81 of this embodiment is
Each of the nozzle groups includes a first nozzle group 81a, a second nozzle group 81b, and a third nozzle group 81c in which three nozzles are arranged at a nozzle pitch k. The first nozzle group 81a and the second nozzle group 81b are separated from each other, and the second nozzle group 81b and the third nozzle group 81c are separated by the group distance pn · D. The parameters of the present embodiment are as follows: the number of nozzles used N = 9, the number of nozzle groups M =
3, the number of group scans S = 1, the nozzle pitch k = 4, and the inter-group distance pn = 5. Therefore, N / (MS) = 9 /
Since (3.1) = 3 and k = 4, N / (MS) and k are relatively prime.

In this embodiment, the nozzle group 81a
The inter-group distance between the nozzle group 81b and the nozzle group 81b and the inter-group distance between the nozzle group 81b and the nozzle group 81c are respectively set to pn. However, the inter-group distance pn may be any integer other than k. The distances may be different values. This is because each of the nozzle groups 81a, 81b, 81c scans the raster independently to execute interlaced printing.

In the case of the present embodiment, as shown in FIG.
The position of the # A1 nozzle in the third main scanning pass P3 is the starting point of the print area, and from here, dot lines can be densely formed in the sub-scanning direction. FIG. 20 is an explanatory diagram showing an enlarged dot formation situation for eight dot lines from the start point of the print area. As shown in FIG. 20, dot lines adjacent in the sub-scanning direction are formed by different nozzles.

Therefore, also in the present embodiment configured as described above, it is possible to obtain the same effect as in the first embodiment of the above-described second printing method.

C-3. Third Embodiment of Second Printing Method Next, a third embodiment of the second printing method of the present invention will be described with reference to FIGS. The feature of this embodiment is that a dot line in the main scanning direction is formed by scanning each nozzle group twice in the main scanning direction.

That is, the print head 9 in the present embodiment
1 includes a first nozzle group 91a and a second nozzle group 91b arranged in the sub-scanning direction via an inter-group distance pn · D, and the nozzle groups 91a and 91b are respectively arranged in the sub-scanning direction. It is formed by arranging six nozzles at a nozzle pitch kD. The parameters of the present embodiment are as follows: the number of nozzles used N = 12, the number of nozzle groups M = 2, the number of group scans S = 2, the nozzle pitch k = 4, the distance between groups p
n = 5. Therefore, N / (M · S) = 12 / (2 ·
2) = 3 and k = 4, so N / (MS) and k are relatively prime.

As shown in FIG. 21, in the present embodiment,
The printing area starts from the position of nozzle # A5 in the third main scanning pass P3, and each dot line is
1a and 91b respectively form two main scans. That is, since each of the nozzle groups 91a and 91b scans each raster twice (S = 2), the dot lines in the main scanning direction include two types of dots indicated by white and black circles, white and black dots, and white and black dots. It is composed of a total of four types of dots including two types of dots indicated by black squares.

FIG. 22 is an explanatory diagram showing an enlarged dot formation state for six dot lines from the start point of the print area.
As shown in FIG. 22, also in the present embodiment, dots adjacent in the sub-scanning direction are formed by different nozzles. In addition, in this embodiment, since the number of group scans in the main scanning direction is set to S = 2, the dot lines that are continuous in the main scanning direction correspond to the nozzle groups 91a and 91b.
Are respectively formed by two main scans. Therefore,
Dots adjacent to each dot line in the main scanning direction are formed by a combination of four different nozzles.

C-4. Next, a fourth embodiment of the second printing method according to the present invention will be described with reference to FIG.
An embodiment will be described. This embodiment is characterized in that all nozzles are grouped into a plurality of nozzle groups by using a single actuator unit and suspending some of the nozzles.

That is, the print head 1 according to the present embodiment
Numeral 01 is formed from a single actuator unit 102, in which a plurality of nozzles are arranged at a predetermined nozzle pitch kD in the sub-scanning direction. Then, in the present embodiment, all nozzles are divided into a first nozzle group 101a and a second nozzle group 101b by suspending a predetermined nozzle 103 indicated by a dotted line among all the nozzles.

By stopping the predetermined nozzle 103, the distance pn between the nozzle groups 101a and 101b is reduced.
This is twice the nozzle pitch k.

In this embodiment configured as described above, the same effect as in the first embodiment of the above-described second printing method can be obtained. In addition to this, in the present embodiment, all nozzles are divided into a plurality of nozzle groups 101a and 101b by suspending some of the nozzles, and a special interlaced printing of the present invention is performed. Even when a defective nozzle such as a missing nozzle occurs in the unit 102, the defective nozzle can be stopped to perform interlace printing.

C-5. Fifth Embodiment of Second Printing Method Next, a fifth embodiment of the second printing method of the present invention will be described with reference to FIGS. The feature of this embodiment is that N nozzles are divided into BN blocks, and M nozzles (M = N /
BN).

FIG. 24 is an explanatory diagram showing the configuration and the like of the print head 111 in the present embodiment.
Reference numeral 11 denotes BN nozzles (BN = 10) for N (N = 10) nozzles.
It is formed divided into blocks of 2). That is, the nozzle pitch k in each block is 4, and the inter-block distance pb between the blocks is 5. Therefore, the physical arrangement of each nozzle is the same as that according to the first embodiment of the second printing method shown in FIG.

However, this embodiment is different from the first embodiment in the constitutional unit for drive control for driving each nozzle, that is, the constitution of the nozzle group. Since each block includes N / BN nozzles (N / BN = 10/2 = 5), the nozzles of each block are assigned the first to N / BN-th order, respectively. be able to.

Referring to FIG. 24, the print head 1
11 includes two blocks 112 and 113, each of which has five nozzles. The nozzles in each block are assigned five ranks a to e, respectively. That is, the first block 112 is constituted by five nozzles a1 to e1, and the second block 1
Reference numeral 13 denotes five nozzles a2 to e2.

In the present embodiment, blocks 112 and 11
One nozzle group is constituted by two nozzles of the same rank in 3. That is, the first nozzle group 111a includes the nozzles a1 and a2, the second nozzle group 111b includes the nozzles b1 and b2, the third nozzle group 111c includes the nozzles c1 and c2, and the nozzles d1 and d2. There are a total of five nozzle groups, a fourth nozzle group 111d and a fifth nozzle group 111e composed of nozzles e1 and e2.

In the present embodiment in which the nozzle groups 111a to 111e are constituted by the nozzles of the same rank in the blocks 112 and 113, the pitch between two nozzles in each nozzle group (ie, the effective nozzle pitch) is ｛K
(M-1) + pb}. Therefore, N / (M · S)
N, M, S, k, and pb are selected so that {k · (M−1) + pb} is relatively prime and N / M
By performing the (M · S) constant-pitch sub-scanning, printing can be performed in an interlace system. In the example shown in FIG. 24, N = 10, M = 5 (N / BN = 10/2 =
5), k = 4, pb = 5, and S = 1, so that N / (M
S) = 10/5 = 2, {k · (M-1) + pb} =
{4 · ((5-1) +5} = 21, and N / (M ·
S) and {k · (M−1) + pb} are in a relatively prime relationship. The sub-scan amount is 10 / (5.1) = 2
It is a dot.

In the printing method shown in FIG. 24, the pitch between groups is k, and the pitch between two nozzles in each nozzle group is {k · (M−1) + pb}. In the present embodiment, the above condition C3b regarding the distance between groups is not satisfied, but the conditions C3a and C3c are satisfied.

In the present embodiment configured as described above,
As shown in FIG. 25, dot lines can be densely formed from the position where the second nozzle a2 of the first nozzle group 111a is located in the eleventh main scanning pass.

In FIG. 24, the nozzles belonging to the blocks 112 and 113 are distinguished from each other by the circles and the squares. However, it is not necessary to distinguish the blocks 112 and 113 from the viewpoint of print control. In No. 25, no distinction is made as to which block each nozzle belongs to. Further, in FIG. 25, the circle of each dot shows the belonging nozzle group, the number of main scanning passes, and the nozzle number. That is, for example,
"B11-2" means that the second nozzle group ("b") is formed by the second nozzle ("-2") in the "11" th main scanning pass.

In the present embodiment configured as above,
As in the above embodiments, dot lines adjacent in the sub-scanning direction can be formed by different nozzles, and high-quality printing can be performed.

In the second printing method, the first printing method is used.
The print head 51 of the fourth embodiment of the printing method (FIG. 1)
5) It is also possible to use the print head 61 (FIG. 16) of the fifth embodiment of the first printing method.

It should be noted that those skilled in the art can appropriately make changes, additions, modifications, deletions, and the like to the respective embodiments of the above-described second printing method without departing from the scope of the present invention. For example, in each embodiment, the case where dots are formed from the main scanning direction as the first scanning direction has been described. However, the present invention is not limited to this, and printing is performed from the sub-scanning direction as the second scanning direction. You can also.

In the second printing method of the present invention, since each raster can be scanned by each dot forming element group, the present invention is not limited to the overlap shown in each embodiment,
Other types of overlap printing can be performed. In other words, a continuous dot line is formed in the first main scan,
By further superimposing new dots on the already formed dots by the next main scan, even more multi-tone printing can be performed.

Further, in each embodiment of the second printing method, a serial printer is exemplified, but the present invention can be applied to a line printer and the like, and can also be applied to a facsimile apparatus and a copying apparatus. Further, the present invention can be applied to a composite printing apparatus in which various functions such as a facsimile function are combined.

As is clear from the above description, according to the second printing method of the present invention, the inter-group distance pn between the dot forming element group and the dot forming element group is changed. Since it is different from the minimum element pitch k of the forming element, a print head having a large number of dot forming elements can be easily formed. Further, each parameter N, M, S, k is selected so that N / (MS) and the minimum element pitch k are mutually prime, and N / (M · S) of the dot pitch D is selected.
S) Since the print recording medium is transported at a constant pitch twice as large, so-called interlaced printing can be performed even when the element pitch of the dot forming element differs in a part of the print head due to the inter-group distance pn.

In the second printing method of the present invention, the inter-group distance pn may be a positive integer other than the minimum element pitch k, and the inter-group distance pn may be different between the dot forming element groups. Since interlaced printing can be performed, a print head having a large number of dot forming elements can be easily obtained.

The present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the gist of the invention.
For example, the following modifications are possible.

(1) In the above embodiment, part of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware. You may do so.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing interlaced printing according to a conventional technique.

FIG. 2 is an explanatory diagram showing basic conditions of a printing method using one nozzle group.

FIG. 3 is an explanatory diagram showing basic conditions of a printing method when the number of scans S is 2 or more.

FIG. 4 is an explanatory diagram showing basic conditions of a first printing method using a plurality of nozzle groups.

FIG. 5 is an explanatory diagram showing basic conditions of a second printing method using a plurality of nozzle groups.

FIG. 6 is a schematic diagram illustrating an overall configuration of a printing apparatus according to a first embodiment of a first printing method of the present invention.

FIG. 7 is a plan view illustrating a structure of a print head.

FIG. 8 is a sectional view showing the structure of a print head.

FIG. 9 is an explanatory diagram illustrating a state of a printing process according to the first embodiment of the first printing method.

FIG. 10 is an explanatory diagram showing an enlarged dot formation situation of FIG. 9;

FIG. 11 is an explanatory diagram illustrating a printing process performed by a printing apparatus according to a second embodiment of the first printing method.

FIG. 12 is an explanatory diagram showing an enlarged dot formation situation in FIG. 11;

FIG. 13 is an explanatory diagram illustrating a state of a printing process of a printing apparatus according to a third embodiment of the first printing method.

FIG. 14 is an explanatory diagram showing an enlarged dot formation situation of FIG. 13;

FIG. 15 is an explanatory diagram showing a state of a printing process of a printing apparatus according to a fourth embodiment of the first printing method of the present invention.

FIG. 16 is an explanatory diagram illustrating a state of a printing process of a printing apparatus according to a fifth embodiment of the first printing method.

FIG. 17 is an explanatory diagram showing a state of a printing process according to the first embodiment of the second printing method of the present invention.

FIG. 18 is an explanatory diagram showing an enlarged dot formation situation of FIG. 17;

FIG. 19 is an explanatory diagram illustrating a state of a printing process of a printing apparatus according to a second embodiment of the second printing method.

FIG. 20 is an explanatory diagram showing an enlarged dot formation situation of FIG. 19;

FIG. 21 is an explanatory diagram illustrating a state of a printing process of a printing apparatus according to a third embodiment of the second printing method.

FIG. 22 is an explanatory diagram showing an enlarged dot formation situation of FIG. 21;

FIG. 23 is an explanatory diagram illustrating a state of a printing process of a printing apparatus according to a fourth embodiment of the second printing method.

FIG. 24 is an explanatory diagram illustrating a configuration and the like of a print head of a printing apparatus according to a fifth embodiment of the second printing method.

FIG. 25 is an explanatory diagram showing an enlarged dot formation situation of FIG. 24;

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer 2 ... Print head 2a, 2b ... Nozzle group 3 ... Main scanning drive unit 4 ... Sub-scanning drive unit 5 ... Drive unit control unit 6 ... Data storage unit 7 ... Print head drive unit 8 ... Main scanning speed management table 10 Actuator unit 11 Flow path forming plate 12 Ink chamber 13 Ink supply port 14 Pressure chamber 15 Vibrating plate 16 Island part 17 Piezoelectric vibrator 20 Nozzle plate 21 Nozzle hole 31 ... print heads 31a, 31b, 31c ... first nozzle group 41 ... print heads 41a, 41b ... nozzle groups 51 ... actuator units 51 ... print heads 61 ... print heads 62 ... nozzle arrays 63 ... actuator units 63a ... even nozzle rows 63b ... odd-numbered nozzle row 71 ... print head 71a, 71b ... nozzle group 81 ... printing C 81a, 81b, 81c: Nozzle group 91: Print head 91a, 91b: Nozzle group 100: Print head 101: Print head 101a, 101b: Nozzle group 102: Actuator unit 103: Nozzle 111: Print head 111a to 111e: Nozzle group 112, 113 ... block

Claims (29)

[Claims] 1. A printing apparatus for performing printing by forming dots in a print area on a print recording medium, comprising: a print head; and at least one of the print head and the print recording medium in a first scanning direction. A first scan drive unit for moving at least one of the print head and the print recording medium in a second scan direction orthogonal to the first scan direction; A print head driving unit that forms dots on the print recording medium by driving the print head based on image data, wherein the print head has N (N is an integer of 4 or more) dot forming elements. And a minimum element pitch along the second scanning direction between two adjacent dot forming elements in the print head is kD (k is an integer, and D is equivalent to a print resolution). The N dot forming elements are classified into M (M and N / M are each an integer of 2 or more) dot forming element groups each including N / M dot forming elements. The i-th (i is an integer of 1 to (M-1)) and (i + 1) -th dot forming element groups in the M dot forming element groups have an inter-group pitch pg _i · D (pg _i Is shifted by an integer different from the k) in the second scanning direction, and the second scanning drive unit controls the print head and the print recording at a constant feed amount of twice or more the dot pitch D. Transporting at least one of the media in the second scanning direction, the first and second scanning driving units and the print head driving unit are located at positions where the M dot forming element groups have the same dot formable position; Having a pattern and the M dot shapes Driving the print head and the print recording medium such that dots can be formed at all dot positions in the print area by shifting the dot formable position patterns of each of the element groups with respect to each other; apparatus. 2. The printing apparatus according to claim 1, wherein adjacent dot forming element groups are separated from each other with a gap along the second scanning direction. / M dot forming elements are arranged such that, in each scan along the first scanning direction, the same N / M dots that are substantially aligned in the second scanning direction are arranged in the minimum element pitch k · A printing device that can be formed with D. 3. The printing apparatus according to claim 2, wherein the same pattern of each of the M dot forming element groups is periodically arranged at a pitch of M dots in the first scanning direction. A printing device composed of a plurality of dot lines. 4. A printing apparatus according to claim 3, between the i-th and (i + 1) th dot forming element groups are separated by inter-group distance pn _i · D (pn _i being an integer) the pn _i values pn ₁ from first to i-th ~p
The remaining (M-1) values obtained by dividing the accumulated value of n _i (pn _i ) by the number M of dot-forming elements are set to take different values from 1 to (M-1). When the first scanning direction is scanned S times (S is a positive integer and M · S is a factor of N) to form a dot line in the first scanning direction, N / (M · S) and k / M are selected so that N / M, S, and k have a prime relationship with each other. The second scanning drive unit selects N / S of the dot pitch D
A printing apparatus that transports at least one of the print head and the print recording medium in the second scanning direction at a double feed amount. 5. The printing apparatus according to claim 4, wherein the print head includes M dot forming element units each having N / M dot forming elements in the second scanning direction. distance are formed by pn _i · D only by separating to dispose in the N / M number of dot forming elements of each dot forming element unit, the minimum element pitch k · in the second scanning direction
A printing device having a pitch equal to D. 6. The printing apparatus according to claim 5, wherein each of the dot forming element units includes a plurality of dot forming elements each having an element having a size twice the minimum element pitch k · D in the second scanning direction. The even-numbered dot forming element row and the odd-numbered dot forming element row formed at a pitch of 2 k
A printing device formed by being spaced apart in the scanning direction. 7. The printing apparatus according to claim 4, wherein the first scan driving unit is configured to control a first scan driving unit according to the number of scans S.
A printing apparatus that drives at least one of the print head and the print recording medium in the first scanning direction at a speed in the scanning direction. 8. The printing apparatus according to claim 2, wherein the same pattern of each of the M dot forming element groups is periodically arranged at a pitch of M dots on each dot line in the first scanning direction. A printing device that is composed of a plurality of dots arranged in a matrix. 9. The printing apparatus according to claim 8, between the i-th and (i + 1) th dot forming element groups are separated by inter-group distance pn _i · D (pn _i being an integer) the pn _i is set to different integer values of k, the first scanning direction M · S times (S is a positive integer, M · S is a factor of N) the scan When forming a dot line in the first scanning direction, N / (MS) and k
Are selected so that N, M, S, and k are coprime with each other. The second scanning drive unit selects N / M of the dot pitch D
A printing apparatus that conveys at least one of the print head and the print recording medium in the second scanning direction at a feed amount of (M · S) times. 10. The printing apparatus according to claim 9, wherein the print head includes M dot forming element units each having N / M dot forming elements in the second scanning direction. distance are formed by pn _i · D only by separating to dispose in the N / M number of dot forming elements of each dot forming element unit, the minimum element pitch k · in the second scanning direction
A printing device having a pitch equal to D. 11. The printing apparatus according to claim 10, wherein each of the dot forming element units has a plurality of dot forming elements that are twice the minimum element pitch k · D in the second scanning direction. The even-numbered dot forming element row and the odd-numbered dot forming element row formed at a pitch of 2 k
A printing device formed by being spaced apart in the scanning direction. 12. The printing apparatus according to claim 9, wherein a part of dots of the plurality of dot forming elements arranged at the minimum element pitch k · D in the second scanning direction in the print head. A printing apparatus, wherein the M dot forming element groups are formed by suspending forming elements. 13. The printing apparatus according to claim 9, wherein the first scan driving unit is configured to move the print head and the print recording medium at a first scan direction speed corresponding to the number of scans M · S. A printing device for driving at least one in the first scanning direction. 14. The printing apparatus according to claim 1, wherein the N dot forming elements are divided into BN (BN is an integer equal to N / M) blocks each including M dot forming elements. Adjacent blocks are separated from each other by an inter-block distance pb · D (pb is a positive integer not equal to k), and the M dot forming element group is determined by a corresponding dot forming element in each block. Are formed, and in each of the scans along the first scanning direction, the same M pieces of the M dot forming elements in each of the blocks are arranged substantially in a line along the second scanning direction. Can be formed at the minimum element pitch kD, and the first scanning direction is scanned MS times (S is a positive integer) to form a dot line in the first scanning direction. When forming The N, M, S, k, and pb are selected so that N / (M · S) and {k · (M−1) + pb} are relatively prime. , N / of the dot pitch D
A printing apparatus that conveys at least one of the print head and the print recording medium in the second scanning direction at a feed amount of (M · S) times. 15. The printing apparatus according to claim 14, wherein the print head is configured to include BN dot forming element units each having M dot forming elements in the second scanning direction with the block distance pb. D, and the M dot forming elements of each dot forming element unit have a pitch equal to the minimum element pitch k · D in the second scanning direction. Printing device. 16. The printing apparatus according to claim 15, wherein each of the dot forming element units has a plurality of dot forming elements in the second scanning direction having an element twice as large as the minimum element pitch k · D. The even-numbered dot forming element row and the odd-numbered dot forming element row formed at a pitch of 2 k
A printing device formed by being spaced apart in the scanning direction. 17. The printing apparatus according to claim 14, wherein a part of dots of the plurality of dot forming elements arranged at the minimum element pitch k · D in the second scanning direction in the print head. The printing apparatus, wherein the BN blocks are formed by suspending a forming element. 18. The printing apparatus according to claim 14, wherein the first scan driving unit is configured to move the print head and the print recording medium at a first scan direction speed corresponding to the number of scans M · S. A printing device for driving at least one in the first scanning direction. 19. A method for forming dots in a print area on the print recording medium while moving at least one of the print head and the print recording medium in a first scanning direction, A printing apparatus that performs printing by using a printing apparatus that moves at least one of them in a second scanning direction orthogonal to the first scanning direction, wherein the number of the printing heads is N (N is an integer of 4 or more). , And the minimum element pitch between two adjacent dot forming elements in the print head along the second scanning direction is kD (k is an integer, and D corresponds to a printing resolution). And the N dot forming elements are classified into M (M and N / M are each an integer of 2 or more) dot forming element groups each including N / M dot forming elements. , Serial i-th among the M number of dot forming element groups (i is. 1 to (M-1) integers) and (i + 1) -th pitch pg _i · D (pg _i between groups dot forming element groups k in the second scanning direction) and at least one of the print head and the print recording medium in the second scanning direction at a constant feed amount of at least twice the dot pitch D. The M dot-forming element groups have the same dot-formable position pattern, and the dot-formable position patterns of the M dot-forming element groups are shifted from each other. A printing method for driving the print head and the print recording medium such that dots can be formed at all dot positions in the print area. 20. The printing method according to claim 19, wherein adjacent dot forming element groups are separated from each other with a gap along the second scanning direction. / M dot forming elements are arranged such that, in each scan along the first scanning direction, the same N / M dots that are substantially aligned in the second scanning direction are arranged in the minimum element pitch k · A printing method which can be formed in D. 21. The printing method according to claim 20, wherein the same pattern of each of the M dot forming element groups is periodically arranged at a pitch of M dots in the first scanning direction. A printing method consisting of multiple dot lines. 22. A printing method according to claim 21, wherein, between the i-th and (i + 1) th dot forming element groups are separated by inter-group distance pn _i · D (pn _i being an integer) the pn _i values pn ₁ from first to i-th ~p
The remaining (M-1) values obtained by dividing the accumulated value (Σpn _i ) of n _{i by} the number M of nozzle groups are set to take different values from 1 to (M−1), The first scanning direction is repeated S times (S is a positive integer and M
(S is a factor of N) When forming the dot lines in the first scanning direction by scanning, the N, M, and N are set so that N / (M · S) and k / M are relatively prime. A printing method, wherein S and k are selected, and at least one of the print head and the print recording medium is transported in the second scanning direction at a feed amount of N / S times the dot pitch D. 23. The printing method according to claim 22, wherein at least one of the print head and the print recording medium is driven in the first scanning direction at a first scanning direction speed corresponding to the number of scans S. Do, printing method. 24. The printing method according to claim 20, wherein the same pattern of each of the M dot forming element groups is periodically arranged at a pitch of M dots on each dot line in the first scanning direction. A printing method consisting of a plurality of dots arranged in a symmetrical manner. 25. The printing method according to claim 24, wherein the first scanning direction is scanned MS times (S is a positive integer and MS is a factor of N). When forming a dot line in the scanning direction 1, N / (M · S) and k
, M, S, and k are selected so as to have a prime relation with each other, and at least one of the print head and the print recording medium at a feed amount of N / (M · S) times the dot pitch D. A printing method in which the image is conveyed in the second scanning direction. 26. The printing method according to claim 25, wherein at least one of the print head and the print recording medium is moved in the first scanning direction at a first scanning direction speed corresponding to the number of scans M · S. Driving method, printing method. 27. The printing method according to claim 19, wherein the N dot forming elements are divided into BN (BN is an integer equal to N / M) blocks each including M dot forming elements. Adjacent blocks are separated from each other by an inter-block distance pb · D (pb is a positive integer not equal to k), and the M dot forming element group is determined by a corresponding dot forming element in each block. Are formed, and in each of the scans along the first scanning direction, the same M pieces of the M dot forming elements in each of the blocks are arranged substantially in a line along the second scanning direction. Can be formed at the minimum element pitch kD, and the first scanning direction is scanned MS times (S is a positive integer) to form a dot line in the first scanning direction. When forming , N / (M · S) and {k · (M−1) + pb} are mutually primed, and N / M / S / k / pb is selected. A printing method, wherein at least one of the print head and the print recording medium is conveyed in the second scanning direction at a (MS) times feed amount. 28. The printing method according to claim 27, wherein at least one of the print head and the print recording medium is moved in the first scanning direction at a first scanning direction speed corresponding to the number of scans M · S. Driving method, printing method. 29. Forming dots in a print area on the print recording medium while moving at least one of the print head and the print recording medium in a first scanning direction, and forming at least one of the print head and the print recording medium. A computer-readable recording medium that records a computer program for a computer that controls a printing apparatus that moves one of the print heads in a second scanning direction orthogonal to the first scanning direction, wherein the number of the print heads is N. (N is an integer of 4 or more), and a minimum element pitch between two adjacent dot forming elements in the print head along the second scanning direction is kD (k is an integer). , D is a dot pitch corresponding to the print resolution, and the N dot forming elements are M (M and M) each including N / M dot forming elements. / M are each classified into two or more dot forming element groups, and the i-th (i is an integer of 1 to (M-1)) and (i + 1) in the M dot forming element groups. The second dot forming element group is shifted in the second scanning direction by an inter-group pitch pg _i · D (pg _i is an integer different from k), and the computer program is twice the dot pitch D A first program for operating the computer so as to convey at least one of the print head and the print recording medium in the second scanning direction with the constant feed amount, and the M dot forming element group By shifting the dot formable position patterns of each of the M dot forming element groups with respect to each other so as to have the same dot formable position pattern, Of such dots it is possible to form a dot position, and a second program for operating the computer, a computer-readable recording medium.