JP2005280050A - Printer and print control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To complement printing easily at a low cost upon occurrence of a trouble in a line head. <P>SOLUTION: In the inkjet printer 1, piezoelectric elements 60a-60c are provided in a line head 60 such that they can move the line head 60 two-dimensionally, e.g. circular movement or elliptical movement along the plane of a print sheet. Even if a trouble occurs in any one nozzle of the line head 60 and ink cannot be ejected, the piezoelectric elements 60a-60c move the line head 60 and complement printing by neighboring nozzles such that missing dots becomes inconspicuous. The inkjet printer 1 can complement printing easily at a low cost upon occurrence of a trouble in the line head 60. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus and a printing control method capable of printing by a single pass.

Currently, inkjet printers that perform printing by ejecting ink from nozzles are widely used.
Such an ink-jet printer includes a head (shuttle head) in which nozzles are arranged in a narrower width than a recording material (printing paper or the like). This type is equipped with a system that performs printing (shuttle head system) and a head (line head) in which nozzles are arranged at the same width or larger as the recording material, and this line head is fixed while moving the recording material. A system (line head system) is known that performs printing by a single pass as it is.

Among these, in the case of a line head type ink jet printer, for example, when the specification is printable on A4 size printing paper, the number of nozzles provided in the line head is at least 10,000.
By the way, in an ink jet printer, a nozzle may be clogged with air, paper dust (print paper dust), or the like.

  In the case of the above-described line head type inkjet printer, since the number of nozzles is extremely large, the probability of nozzle clogging is higher. Also, in the case of a line head type ink jet printer, the line head is generally provided with nozzles for only one line, so when nozzle clogging occurs, white streaks (clogged nozzles) appear in the printed image. The unprinted part) appears.

In order to solve such a problem, Japanese Patent Application Laid-Open No. 2-276647 discloses a complementary head such as a shuttle head in addition to the line head, so that when a nozzle is clogged, this supplement is performed. A technique for supplementing printing with a special head is disclosed.
As a similar technique, Japanese Patent Application Laid-Open No. 8-174805 has two line heads having the same nozzle arrangement, and when the nozzle of one line head is clogged, printing is performed by the other line head. The technology which complements is disclosed.
JP-A-2-276647 JP-A-8-174805

However, in the technique described in Japanese Patent Laid-Open No. 2-276647, since it is necessary to provide a shuttle head in addition to the line head, the cost is increased and the printing position corresponding to the clogged nozzle is set. There is a problem that it is difficult to accurately move the shuttle head to print.
Further, the technique described in Japanese Patent Application Laid-Open No. 8-174805 also has a problem of increasing the cost because it is necessary to provide two similar line heads.

As described above, in the conventional technique, it is difficult to supplement printing easily at low cost when a problem occurs in the line head.
Such a problem is common to a single-pass printing apparatus having a line head.
An object of the present invention is to make it possible to supplement printing easily and at low cost when a problem occurs in a line head.

In order to solve the above problems, the present invention provides:
A print head (for example, the line head 60 in FIGS. 1 and 2) in which nozzles are arranged over the entire width of a print target region of a recording material (for example, printing paper or an OHP sheet) is provided. A printing apparatus capable of printing in a single pass by relatively moving the recording material and the print head so as to be conveyed in a direction crossing the arrangement direction, and is printed by the nozzle. It is characterized by comprising drive means for changing the pixel position two-dimensionally within the printing surface of the recording material.

Here, the two-dimensional change of the pixel position printed by the nozzle within the printing surface of the recording material is various in a direction other than the direction parallel to the nozzle arrangement direction and the direction parallel to the recording material conveyance direction. It is only necessary to change in the direction including the components in both directions.
As a result, the drive unit can move the print head two-dimensionally along the printing surface of the recording material, so that any nozzle of the print head has a problem and ink is not ejected. However, printing can be supplemented by the nearby nozzles, and dot omission can be made inconspicuous.

That is, according to such a configuration, it is not necessary to provide a supplementary print head, and complementary printing can be easily performed on pixels in which dot missing has occurred. In addition, it is possible to supplement printing easily at low cost.
The drive means is a piezoelectric element (for example, piezoelectric elements 60a to 60c in FIG. 2) that is attached to the print head and is capable of moving the print head along the printing surface of the recording material. Yes.

Thereby, the drive means can be made small and easy to control.
In addition, the driving unit moves the print head by applying a voltage according to a predetermined periodic function (for example, a sine function or a cosine function) to the piezoelectric element.
This makes it possible to draw a periodic trajectory for each nozzle of the print head.

Further, the driving means is characterized in that the print head is moved in the nozzle arrangement direction more than the nozzle interval in the nozzle arrangement.
Thereby, even when a problem occurs in a specific nozzle, printing can be supplemented by at least the adjacent nozzles.
Further, the drive means moves the print head in the conveyance direction of the recording material at a speed equal to or higher than a conveyance speed that relatively moves the recording material and the print head.

As a result, it is possible to cause the nozzles moved by the driving means to draw a trajectory suitable for supplementing printing.
In addition, the driving unit causes each nozzle of the print head to discharge ink only at a pixel position where printing is scheduled when performing printing by a single pass.
Thereby, it is possible to selectively print pixel positions where dots are missing when normal printing is performed due to a nozzle defect.

Further, the driving means moves the print head so as to draw a spiral of a predetermined period on the printing surface of the recording material being conveyed, and the phase of each nozzle of the print head is π within the period. / 2 It is characterized in that ink is ejected every time it travels.
This makes it possible to perform printing at a predetermined pixel position with easy control while enabling supplementary printing.

Further, the driving means moves the print head so as to draw a spiral with a predetermined cycle on the printing surface of the recording material being conveyed, and one nozzle of the printing head has a printing surface of the recording material. The print head is moved to a state where the spiral drawn above and the spiral drawn by the one nozzle are in contact with or intersecting each other.
As a result, the nozzles moved by the driving means pass through the print pixel positions more appropriately and redundantly.

Further, the apparatus further includes nozzle abnormality detection means (for example, the nozzle abnormality detection unit 40 in FIG. 1) for detecting that a defect has occurred in the nozzles of the print head, and the drive means detects abnormality by the nozzle abnormality detection means. The pixel position corresponding to the detected nozzle is characterized by increasing the amount of ink ejected by other nozzles.
As a result, it is possible to make the pixel in which the ink ejection amount is reduced due to the nozzle failure more inconspicuous.

The driving means is a piezoelectric element that is attached to the nozzle and changes the direction of the opening of the nozzle.
As a result, it is possible to supplement printing with different trajectories for each nozzle, so that it is possible to supplement printing more flexibly.
Further, the print heads corresponding to a plurality of print colors are provided, and each of the print heads is provided with the driving unit.

Thus, even in a printing apparatus having a plurality of print heads such as a color printing apparatus, it is possible to perform printing supplementation according to the present invention.
The present invention also provides:
Using the print head in which the nozzles are arranged over the entire width of the printing target area of the recording material, the recording material and the print head are conveyed so that the recording material is conveyed in a direction intersecting the nozzle arrangement direction. Is a printing control method for a printing apparatus that can perform printing in a single pass by relatively moving the position of the pixel in two dimensions within the printing surface of the recording material. It is characterized by including a driving step to be changed.

  According to the present invention, when a problem occurs in the line head, printing can be complemented easily at low cost.

Hereinafter, embodiments of a printing apparatus according to the present invention will be described with reference to the drawings.
First, the configuration will be described.
FIG. 1 is a block diagram showing a functional configuration of an inkjet printer 1 to which the present invention is applied. FIG. 2 is a schematic diagram showing the configuration of the printing mechanism of the inkjet printer 1.
1 and 2, the inkjet printer 1 includes an interface unit 10, a print data processing unit 20, a drive control unit 30, a nozzle abnormality detection unit 40, a paper transport unit 50, and a line head 60. Composed.

  The interface unit 10 includes a data communication port based on USB (Universal Serial Bus) or RS-232, and a media slot that can read a storage medium such as a memory card. Then, the interface unit 10 outputs the data (print data) input via the data communication port or the media slot to the print data processing unit 20.

  The print data processing unit 20 analyzes the print data input from the interface unit 10 and generates raster image data corresponding to the nozzle arrangement of the line head 60. Specifically, the print data processing unit 20 generates raster image data that is an array of pixel data to be printed by each nozzle of the line head 60 based on the resolution and size of the print data input from the interface unit 10. . Then, the print data processing unit 20 outputs the generated raster image data to the drive control unit 30.

  The drive control unit 30 controls ink ejection timing at each nozzle of the line head 60 based on the raster image data input from the print data processing unit 20. That is, the drive control unit 30 causes ink to be ejected from each nozzle of the line head 60 according to each pixel data indicated by the raster image data at a timing according to the speed at which the printing paper is conveyed by the paper conveyance unit 50. .

  Further, the drive control unit 30 receives a line indicating that an abnormality has occurred in any of the nozzles (hereinafter referred to as “nozzle abnormality signal”) from a nozzle abnormality detection unit 40 described later. A head drive process (described later) is executed. Then, when executing the line head driving process, the drive control unit 30 drives piezoelectric elements 60a to 60c (described later) provided in the line head 60, and the line head 60 is moved back and forth and left and right along the paper surface of the printing paper. Move to.

  The nozzle abnormality detection unit 40 detects whether an abnormality such as clogging has occurred in each nozzle provided in the line head 60. As a method for detecting an abnormality in a nozzle, a method for detecting an abnormality in each nozzle by irradiating the ink ejected from the nozzle with a laser beam and detecting the reflected light, a laser beam is applied to the print pixel column at the top of the page. Is used to detect abnormalities in each nozzle by detecting the reflected light, and the electrical load required to eject ink at each nozzle is measured, and abnormalities are detected based on differences from normal conditions. It is possible to adopt a conventionally used method such as a method.

The paper transport unit 50 includes a paper feed roller that is driven by a stepping motor (not shown), and transports print paper at a constant speed in accordance with an instruction from the drive control unit 30.
The line head 60 has a nozzle group arranged over the same width as the printing paper, and can eject ink from each nozzle to the printing paper conveyed by the paper conveyance unit 50. is there. Here, for the sake of simplicity, an example in which the line head 60 has a configuration in which nozzles are arranged in a line and performs printing in one color will be described.

  Further, the line head 60 is provided with piezoelectric elements 60a to 60c for moving the line head 60 in each of the nozzle arrangement direction and the direction orthogonal thereto in a plane along the plane of the printing paper, and these piezoelectric elements 60a. ˜60c through the main body. That is, the piezoelectric elements 60 a and 60 c are provided opposite to the left and right end faces of the line head 60, and the piezoelectric element 60 b is provided on the back surface of the line head 60. When the line head driving process is executed, the piezoelectric elements 60a to 60c are driven by the drive control unit 30 so that each nozzle of the line head 60 spirals (on the plane) along the surface of the printing paper. Can be drawn.

FIG. 3 is a diagram showing a spiral that one nozzle (hereinafter referred to as “nozzle X”) in the line head 60 draws on the printing paper when a voltage is applied to the piezoelectric elements 60a to 60c.
In the spiral shown in FIG. 3, the period from the point P to the point Q in the direction of the arrow and the path from the point R to the point R is referred to as one cycle, and the horizontal width of the spiral is the spiral width and one cycle of the spiral on the printing paper. The distance traveled in the transport direction is referred to as a spiral pitch.

  The spiral width of the nozzle X is determined by the distance that the piezoelectric elements 60a and 60c move the line head 60, that is, the voltage applied to the piezoelectric elements 60a and 60c, and the spiral as shown in FIG. 3 is, for example, a sine function (sinωt) or It is possible to draw by applying a voltage according to a characteristic such as a cosine function (cos ωt) (where ω is an angular velocity and t is a time). Note that the voltages applied to the piezoelectric elements 60a and 60c have the same direction of amplitude, such as shifting the phase by π, and are controlled so as not to cancel the forces generated by each other.

Further, the spiral pitch of the nozzle X is determined by a relative relationship between the conveyance speed of the printing paper and the speed at which the piezoelectric element 60 b moves the line head 60.
FIG. 4 is a diagram showing a spiral when the relationship between the printing paper conveyance speed and the speed at which the piezoelectric element 60 b moves the line head 60 is different.
In FIG. 4, when the speed at which the piezoelectric element 60b moves the line head 60 is slower than the conveyance speed of the printing paper, the spiral pitch becomes relatively long (see FIG. 4A). When the speed at which the element 60b moves the line head 60 is high, the spiral pitch is relatively short (see FIG. 4B).

  In the line head driving process, the nozzle draws a spiral, so that a plurality of nozzles pass over one pixel, and the pixel in which the missing dot is generated due to the nozzle failure is complemented. For this reason, the moving speed of the line head 60 by the piezoelectric element 60b needs to be higher than the conveying speed of the printing paper, and a more preferable state is a state where the trajectories of each cycle of the spiral overlap each other. Therefore, the moving speed of the line head 60 by the piezoelectric element 60b is such that the trajectory of each cycle of the spiral is in contact as shown in FIG. 4C, or the trajectory of each cycle of the spiral as shown in FIG. 4B. It is preferable to set in a state where the crosses.

  When the inkjet printer 1 is specifically designed in the above configuration, for example, the nozzle interval is 141 [μm], the applied voltage period of the piezoelectric elements 60a to 60c is 2.5 [kHz], and the nozzle movement speed. Can be 2.2 [m / sec], the printing paper conveyance speed can be 0.28 [m / sec], and the like. A nozzle interval of 141 [μm] corresponds to a resolution of 180 [dpi].

Next, the operation will be described.
The ink jet printer 1 performs a normal printing operation when the nozzle abnormality detection unit 40 detects no abnormality in any nozzle. That is, the instructed image is printed by controlling the ejection of ink from each nozzle of the stationary line head 60 without moving the line head 60 by the piezoelectric elements 60a to 60c.

On the other hand, when the nozzle abnormality detection unit 40 detects an abnormality in any one of the nozzles, the inkjet printer 1 performs a line head driving process and prints while moving the line head 60 by driving the piezoelectric elements 60a to 60c. I do.
Here, when the line head driving process is executed, the spiral width of the nozzle is set to be at least an interval between adjacent nozzles (hereinafter referred to as “nozzle interval”). The spiral pitch of the nozzle is set to the state shown in FIG. 4B or 4C.

FIG. 5 is a diagram illustrating an example of the relationship between print pixels and nozzle trajectories.
In FIG. 5, in all the print pixels arranged in a grid pattern, the nozzles pass through the pixels three times.
That is, if the nozzle of interest is nozzle A, the right adjacent nozzle is nozzle B, the right adjacent nozzle is nozzle C,..., The nozzle A is the pixel in the first row and third column when the phase ωt = 0. Ink is ejected (droplet A-1).

The nozzle A ejects ink to the pixels in the second row and second column when the phase ωt = π / 2 (droplet A-2), and further, the first row when the phase ωt = 3π / 2. Ink is ejected to the second row of pixels (droplet A-3).
Next, the nozzle A ejects ink to the pixels in the second row and the third column when the phase ωt = 2π (droplet A-4).

With such an operation as one cycle, the nozzle A thereafter draws a similar locus.
On the other hand, the nozzle B ejects ink to the pixels in the first row and the fourth column when the phase ωt = 0 (droplet B-1).
The nozzle B ejects ink to the pixels in the second row and third column when the phase ωt = π / 2 (droplet B-2), and further, the first row when the phase ωt = 3π / 2. Ink is ejected to the pixels in the third row (droplet B-3).

Next, the nozzle B ejects ink to the pixels in the second row and the fourth column when the phase ωt = 2π (droplet B-4).
Similarly, the nozzle C ejects ink to the pixels in the first row and the fifth column when the phase ωt = 0 (droplet C-1).
The nozzle C ejects ink to the pixels in the second row and the fourth column when the phase ωt = π / 2 (droplet C-2), and further, the first row when the phase ωt = 3π / 2. Ink is ejected to the pixels in the fourth column (droplet C-3).

Next, the nozzle C ejects ink to the pixels in the second row and the fifth column when the phase ωt = 2π (droplet C-4).
As a result, ink is ejected from each of the plurality of nozzles to each pixel, and as a result, ink can be ejected by three drops.
Therefore, even when a problem occurs in any of the nozzles, it is possible to supplement printing by using neighboring nozzles without causing missing dots.

FIG. 6 is a diagram illustrating a printing result when the nozzle B has a defect in the example illustrated in FIG.
In FIG. 6, since the nozzle B is defective and ink cannot be ejected, the droplet B-1 in the first row and the fourth column, the droplet B-2 in the second row and the third column, The droplet B-6, the droplet B-3 in the first row and the third column, and the droplet B-4 in the second row and the fourth column are missing.

However, droplets are ejected to these pixels by nozzle A or nozzle C, and the pixels are printed.
Therefore, it is possible to avoid a state in which dots are completely missing even when any nozzle has a problem.
In the state shown in FIG. 6, since the ink discharge amount decreases in the pixel located on the locus of the defective nozzle, the defective nozzle is identified by the nozzle abnormality detection unit 40, and the pixel is Adjacent nozzles (nozzles A and C) that pass through may increase the amount of ink discharged.

FIG. 7 is a schematic diagram showing a state in which the amount of ink discharged from other nozzles is increased with respect to the pixels from which liquid droplets are missing in FIG.
As shown in FIG. 7, by ejecting a large amount of ink from the other nozzles to the pixels from which the liquid droplets from the nozzle B have fallen, it is possible to make the state in which the liquid droplets ejected by the nozzle B are missing become inconspicuous. It becomes.

In addition to the relationship between the print pixel and the nozzle trajectory shown in FIG. 5, the following settings are also possible.
FIG. 8 is a diagram illustrating another example of the relationship between the print pixel and the nozzle trajectory.
In FIG. 8, among the print pixels arranged in a grid pattern, the nozzle passes a total of three times on the pixels of the first, third, and fifth rows, and the remaining pixels on the second and fourth rows are displayed on the pixels. The nozzle has passed only once.

That is, the nozzle A ejects ink to the pixels in the first row and the third column when the phase ωt = 0 (droplet A-1).
The nozzle A ejects ink to the pixels in the third row and the second column when the phase ωt = π / 2 (droplet A-2), and further, the second row first when the phase ωt = π. Ink is ejected to the pixels in the column (droplet A-3).

Subsequently, the nozzle A ejects ink to the pixels in the first row and the second column when the phase ωt = 3π / 2 (droplet A-4), and then the third row starts when the phase ωt = 2π. Ink is ejected to three rows of pixels (droplet A-5).
With such an operation as one cycle, the nozzle A thereafter draws a similar locus.
On the other hand, the nozzle B ejects ink to the pixels in the first row and the fourth column when the phase ωt = 0 (droplet B-1).

In addition, the nozzle B ejects ink to the pixels in the third row and third column when the phase ωt = π / 2 (droplet B-2), and further, the second row second when the phase ωt = π. Ink is ejected to the pixels in the column (droplet B-3).
Subsequently, the nozzle B ejects ink to the pixels in the first row and third column when the phase ωt = 3π / 2 (droplet B-4), and then the third row starts when the phase ωt = 2π. Ink is ejected to the four rows of pixels (droplet B-5).

Similarly, the nozzle C ejects ink to the pixels in the first row and the fifth column when the phase ωt = 0 (droplet C-1).
In addition, the nozzle C ejects ink to the pixels in the third row and the fourth column when the phase ωt = π / 2 (droplet C-2), and further, when the phase ωt = π, the second row third. Ink is ejected to the pixels in the column (droplet C-3).

Subsequently, the nozzle C ejects ink to the pixels in the first row and the fourth column when the phase ωt = 3π / 2 (droplet C-4), and then the third row starts when the phase ωt = 2π. Ink is ejected to five rows of pixels (droplet C-5).
As a result, three drops of ink are discharged to the pixels in the first, third, and fifth rows, and one drop of ink is discharged to the pixels in the second and fourth rows.

When the line head driving process of the locus as shown in FIG. 5 is performed, the ink ejection timing at the nozzles is irregular with phases ωt = 0, π / 2, 3π / 2, 2π, but as shown in FIG. In a line head driving process with a simple trajectory, the ejection timing may be performed for each phase ωt = 0, π / 2, π, 3π / 2, 2π, and π / 2.
Therefore, in the line head driving process of the locus as shown in FIG. 5, although it is not possible to perform uniform printing for all the pixels, the ink ejection timing at the nozzle is simple, and the nozzle can be controlled easily. .

Then, by performing the line head driving process shown in FIG. 8, if any of the nozzles malfunctions, the pixels in the first, third, and fifth rows can be complemented by the neighboring nozzles. Therefore, it is possible to make dot missing due to a nozzle defect inconspicuous.
As described above, the ink jet printer 1 according to the present embodiment includes the line head 60 including the piezoelectric elements 60a to 60c, and the piezoelectric elements 60a to 60c cause a circular motion or an elliptical motion along the paper surface of the printing paper. As described above, the line head 60 can be moved two-dimensionally.

Therefore, even if a problem occurs in any nozzle of the line head 60 and ink is not ejected, the line head 60 is moved by the piezoelectric elements 60a to 60c, so that printing is complemented by neighboring nozzles. It is possible to make dot missing inconspicuous.
That is, according to the inkjet printer 1, it is not necessary to provide a complementary line head, and it is possible to easily perform complementary printing on pixels in which missing dots occur. In addition, it is possible to supplement printing easily at low cost.

In the present embodiment, it has been described that the line head driving process is executed only when an abnormality occurs in any of the nozzles. However, the line head driving process may be always executed.
Further, when the line head driving process is performed, the pixel in which the missing dot is generated is complemented and printed by the neighboring nozzles, and therefore, there is a situation in which there is no nozzle that complements printing for the pixels at the nozzle positions at both ends. Occur.

Therefore, in order to complement the printing of pixels in the line head driving process, in addition to the nozzles required in the normal printing operation, one or two complementary nozzles may be provided at both ends of the nozzle array. good.
Further, in the present embodiment, the line head 60 includes the piezoelectric elements 60a to 60c, and the position of the entire line head 60 is changed, and the pixel position corresponding to the defective nozzle is printed by another nozzle. However, as shown in FIG. 9, a piezoelectric element that changes the direction of the opening of each nozzle is provided, and by changing the ink ejection direction, a pixel in which a missing dot is generated by a nearby nozzle is complemented. It is also possible to print it.

In this case, since ink can be ejected from each nozzle in different directions, printing can be performed with more flexible pixel complementation.
Furthermore, in the present embodiment, the case where the line head 60 has an array of nozzles in one row and the number of the line heads 60 is one has been described. However, the line head 60 has a plurality of nozzle arrays. Alternatively, as shown in FIG. 10, a plurality of line heads 60 may be provided corresponding to the printing color.

Even in such a case, it is possible to apply the present invention and perform printing by complementing the pixels in which dot missing has occurred.
In addition, as an application of the present invention, it is possible to perform printing with a high pixel density that is not limited by the nozzle interval by setting the ink ejection timing to a shorter time interval when the line head driving process is executed.

  Furthermore, in the present invention, since the ink is ejected a plurality of times for the same pixel and printing is performed, the gradation of the pixel can be increased.

2 is a block diagram illustrating a functional configuration of the inkjet printer 1. FIG. 1 is a schematic diagram illustrating a configuration of a printing mechanism of an inkjet printer 1. FIG. It is a figure which shows the spiral which the nozzle X draws on a printing paper, when a voltage is applied to the piezoelectric elements 60a-60c. It is a figure which shows a spiral in case the relationship between the conveyance speed of a printing paper and the speed which the piezoelectric element 60b moves the line head 60 differs. It is a figure which shows an example of the relationship between the printing pixel and the locus | trajectory of a nozzle. In the example shown in FIG. 5, it is a figure which shows the printing result in case the malfunction has arisen in the nozzle B. FIG. FIG. 7 is a schematic diagram showing a state in which the ejection amount of ink from other nozzles is increased with respect to pixels from which liquid droplets are missing in FIG. 6. It is a figure which shows the other example of the relationship between the printing pixel and the locus | trajectory of a nozzle. It is a figure which shows the example in the case of providing the line head 60 with the piezoelectric element which changes the direction of the opening part of each nozzle. It is a figure which shows the example in the case of providing multiple line heads 60 corresponding to printing color.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer, 10 interface part, 20 print data processing part, 30 drive control part, 40 nozzle abnormality detection part, 50 paper conveyance part, 60 line head, 60a-60c piezoelectric element

Claims (12)

A print head in which nozzles are arranged over the entire width of the print target area of the recording material, and the recording material and the print head are conveyed so that the recording material is conveyed in a direction intersecting the nozzle arrangement direction. A printing apparatus capable of printing by a single pass by moving relatively,
A printing apparatus comprising: drive means for two-dimensionally changing a pixel position printed by the nozzle in a printing surface of the recording material.   The printing apparatus according to claim 1, wherein the driving unit is a piezoelectric element attached to the print head and capable of moving the print head along a printing surface of a recording material.   The printing apparatus according to claim 2, wherein the driving unit moves the print head by applying a voltage according to a predetermined periodic function to the piezoelectric element.   4. The printing apparatus according to claim 1, wherein the driving unit moves the print head in a nozzle arrangement direction at least a nozzle interval in the nozzle arrangement. 5.   The drive means moves the print head in the conveyance direction of the recording material at a speed equal to or higher than a conveyance speed that relatively moves the recording material and the print head. 5. The printing apparatus according to any one of 4 above.   The said drive means makes each nozzle of the said print head discharge ink only in the pixel position where printing is planned when performing printing by a single pass. The printing apparatus as described in.   The drive means moves the print head so as to draw a spiral with a predetermined period on the printing surface of the recording material being conveyed, and the phase of each nozzle of the print head is π / 2 within the period. The printing apparatus according to claim 1, wherein ink is ejected each time the ink advances.   The drive means moves the print head so as to draw a spiral of a predetermined cycle on the printing surface of the recording material being conveyed, and one nozzle of the printing head is on the printing surface of the recording material. 8. The printing apparatus according to claim 1, wherein the print head is moved to a state in which the spiral to be drawn is in contact with or intersects with the spiral that has been previously drawn by the one nozzle. . Further comprising nozzle abnormality detection means for detecting that a problem has occurred in the nozzles of the print head,
9. The drive unit according to claim 1, wherein the drive unit increases the amount of ink ejected by another nozzle at a pixel position corresponding to the nozzle in which the abnormality is detected by the nozzle abnormality detection unit. The printing apparatus as described in.   The printing apparatus according to claim 1, wherein the driving unit is a piezoelectric element that is attached to the nozzle and changes a direction of an opening of the nozzle.   The printing apparatus according to claim 1, further comprising: the print head corresponding to each of a plurality of print colors, wherein each of the print heads includes the driving unit. Using the print head in which the nozzles are arranged over the entire width of the printing target area of the recording material, the recording material and the print head are conveyed so that the recording material is conveyed in a direction intersecting the nozzle arrangement direction. Is a printing control method of a printing apparatus capable of printing by a single pass by relatively moving
The printing control method characterized by including the drive step which changes the pixel position printed by the said nozzle two-dimensionally within the printing surface of the said to-be-recorded material.

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