JP2017024232A - Droplet discharge device and adjustment method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge device capable of easily improving a reduction in printing quality due to an inclination of an ink jet head, and an adjustment method for the droplet discharge device.SOLUTION: In a droplet discharge device comprising: a transportation section moving a printing medium in a sub-scanning direction (first direction); a droplet discharge section 20 having a plurality of nozzle arrays constituted of a plurality of nozzles disposed side-by-side in a predetermined direction for discharging ink onto a printing medium; and a scanning moving section scanning and moving the droplet discharge section 20 in a scanning direction (second direction), an inclination in the predetermined direction with respect to the sub-scanning direction (first direction) is corrected, and positions of the plurality of nozzles discharging the ink are corrected on the basis of a correction amount corrected in a plane surface including the sub-scanning direction (first direction) and the scanning direction (second direction).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a droplet discharge device and a method for adjusting a droplet discharge device.

  In response to demands for higher quality (higher resolution) of printed images and higher printing speeds, droplet ejection devices represented by inkjet printers have advanced the miniaturization of nozzles mounted on printer heads. Has increased. In addition, the type of ink used has been increased. As a result, the number of ink jet heads constituting the printer head has increased, and securing and maintaining the mounting accuracy has been a problem. On the other hand, for example, Patent Document 1 proposes a printer head provided with a dial type adjusting means for adjusting the inclination of each ink jet head.

JP 2008-62534 A

  However, in the printer head described in Patent Document 1, although it is possible to individually adjust the inclination of the ink jet head with high accuracy, the time required for the adjustment work increases as the number of ink jet heads mounted increases. There was a problem of doing it. In addition, since it is necessary to provide adjusting means for each ink jet head, there is a problem that the cost of the printer head increases.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples or forms.

  Application Example 1 A method for adjusting a droplet discharge device according to this application example includes a transport unit that moves a print medium in a first direction, and a plurality of nozzles arranged in a predetermined direction that discharges droplets onto the print medium. A method for adjusting a droplet discharge device, comprising: a droplet discharge unit having a plurality of nozzle rows each configured by: a scan moving unit that scans and moves the droplet discharge unit in a second direction; And correcting the inclination of the predetermined direction with respect to the first direction within a plane including the second direction, and correcting the position of the nozzle that discharges the droplet based on the corrected correction amount. Features.

  According to this application example, when a predetermined direction (nozzle row direction) in which nozzles are arranged has an inclination with respect to the first direction, the inclination is corrected. Further, the position of the nozzle that ejects the droplet is corrected based on the correction amount. As a result, the plurality of nozzle rows arranged in the second direction can form dots arranged in the first direction. Further, since the position of the nozzle that discharges the droplet is corrected with respect to the nozzle whose position changes in the first direction by the correction of the inclination, the influence of the correction of the inclination on the formed image can be suppressed. it can.

  Application Example 2 In the method of adjusting a droplet discharge device according to the application example, the correction amount is θ, the distance between the adjacent nozzle rows in the second direction is Dx, and the nozzle row is scanned in the second direction. When the distance between the plurality of dot rows formed in the second direction by the droplet ejected while moving is dp, the droplet is ejected based on a value calculated by Dx · sin θ / dp. The position of the nozzle to be corrected is corrected.

  According to this application example, the position of the nozzle that discharges the droplet is corrected based on the value calculated by Dx · sin θ / dp. The value of Dx · sin θ is such that the position of the nozzle row adjacent in the second direction varies in the first direction due to the inclination correction. This size and dp (distance between a plurality of dot rows formed in the second direction by droplets ejected while the nozzle row is scanned and moved in the second direction, that is, the interval between the nozzle positions in the first direction) The position of the nozzle that discharges the droplet is corrected based on the value of the ratio. For example, a suitable correction can be performed by shifting the nozzle positions to be ejected by a natural number obtained by rounding off the ratio value.

  Application Example 3 In the method for adjusting a droplet discharge device according to the application example, the droplets are discharged from the nozzles in a state where the droplet discharge unit is stationary with respect to the print medium. Forming a first dot row aligned in the predetermined direction, and discharging the droplets from the specific nozzles while scanning and moving the droplet discharge portion in the second direction. Forming a second dot row arranged in a second direction, and obtaining an inclination in the predetermined direction with respect to the first direction from an angle formed by the first dot row and the second dot row. It is characterized by that.

  According to this application example, the amount to be easily corrected can be obtained by observing the angle formed between the first dot row and the second dot row formed on the print medium.

  Application Example 4 A droplet discharge device according to this application example includes a transport unit that moves a print medium in a first direction and a plurality of nozzles that are arranged in a predetermined direction to discharge droplets onto the print medium. In the plane including the droplet discharge unit having a plurality of nozzle rows, the scan moving unit that scans and moves the plurality of nozzle rows in the second direction, and the plane including the first direction and the second direction, the first An inclination correction unit capable of correcting the inclination of the predetermined direction with respect to a direction, and a control unit for correcting the position of the nozzle that discharges the droplet based on the correction amount corrected by the inclination correction unit. It is characterized by providing.

  According to this application example, when a predetermined direction (nozzle row direction) in which nozzles are arranged has an inclination with respect to the first direction, the inclination is corrected. Further, based on this correction amount, the position of the nozzle that discharges the droplet is corrected by the control unit. As a result, the plurality of nozzle rows arranged in the second direction can form dots arranged in the first direction. Further, since the position of the nozzle that discharges the droplet is corrected with respect to the nozzle whose position changes in the first direction by the correction of the inclination, the influence of the correction of the inclination on the formed image can be suppressed. it can.

  Application Example 5 In the droplet discharge device according to the application example described above, the correction amount is θ, the distance between the adjacent nozzle rows in the second direction is Dx, and the nozzle rows are scanned and moved in the second direction. Based on the value calculated by Dx · sin θ / dp, the control unit sets the distance between the plurality of dot rows formed in the second direction by the droplets to be ejected to dp. The position of the nozzle that discharges ink is corrected.

  According to this application example, the position of the nozzle that discharges the droplet is corrected based on the value calculated by Dx · sin θ / dp. The value of Dx · sin θ is such that the position of the nozzle row adjacent in the second direction varies in the first direction due to the inclination correction. This size and dp (distance between a plurality of dot rows formed in the second direction by droplets ejected while the nozzle row is scanned and moved in the second direction, that is, the interval between the nozzle positions in the first direction) The position of the nozzle that discharges the droplet is corrected based on the value of the ratio. For example, a suitable correction can be performed by correcting the nozzle positions by the natural number obtained by rounding off the ratio value.

1 is a front view illustrating a configuration of a droplet discharge device according to Embodiment 1. FIG. 1 is a block diagram illustrating a configuration of a droplet discharge device according to a first embodiment. Illustration of print data generation processing by the printer driver Plan view showing the configuration of the printer head The top view which expands a part of ink discharge head and shows the relationship with the dot position formed with the discharged ink A plan view showing the distortion of the base body that bundles the ink discharge heads Example of tilt θ detection image printed to detect tilt θ Plan view showing the configuration of the tilt correction unit Plan view showing a state in which the inclination θ is corrected Example of image for detecting inclination θ after correction of inclination θ A plan view for explaining an example of a printer head that has been subjected to a slip position correction process

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. In the following drawings, the scale may be different from the actual scale for easy understanding. Also, in the coordinates added to the drawings, the Z-axis direction is the vertical direction, the + Z direction is the upward direction, the X-axis direction is the front-rear direction, the -X direction is the front direction, the Y-axis direction is the left-right direction, and the + Y direction is the left direction. The XY plane is a horizontal plane.

(Embodiment 1)
FIG. 1 is a front view showing a configuration of a droplet discharge device 1 according to Embodiment 1, and FIG. 2 is a block diagram.
The droplet discharge device 1 includes an inkjet printer 100 (hereinafter referred to as printer 100), a personal computer 110 (hereinafter referred to as PC 110), and the like.
The printer 100 is an inkjet printer that prints a desired image on a long print medium 5 that is supplied in a rolled state based on print data received from the PC 110.

<Personal computer (PC110)>
The PC 110 includes a printer control unit 111 as a “control unit”, an input unit 112, a display unit 113, a storage unit 114, and the like, and controls a print job that causes the printer 100 to perform printing.
The printer control unit 111 includes a CPU (calculation unit), storage elements such as a RAM and a ROM (not shown), and performs centralized management of the entire droplet discharge device 1.
The input unit 112 is information input means as a human interface. Specifically, for example, a port to which a keyboard or an information input device is connected.
The display unit 113 is information display means (display) as a human interface, and is based on the control of the printer control unit 111, information input from the input unit 112, information to be printed on the printer 100, and information based on the print job. Etc. are displayed.
The storage unit 114 is a rewritable storage medium such as a hard disk drive (HDD) or a memory card. The storage unit 114 stores software (a program running on the printer control unit 111) that operates the PC 110, information to be printed, information based on a print job, and the like. Remembered.

  The software for operating the PC 110 includes general image processing application software (hereinafter referred to as an application) and printer driver software (hereinafter referred to as a printer driver) described later.

<Basic configuration of inkjet printer (printer 100)>
The printer 100 includes a printing unit 10, a conveyance unit 40, a scanning movement unit 50, a controller 60, and the like. The printer 100 that has received the print data from the PC 110 controls each drive unit (the print unit 10, the conveyance unit 40, and the scanning movement unit 50) by the controller 60 based on the print data, and prints an image on the print medium 5 (image Form.
The print data is, for example, image forming data obtained by converting general RGB digital image information obtained by a digital camera or the like so that it can be printed by the printer 100 using an application and printer driver included in the PC 110. Commands that control 100 are included.

The printing unit 10 includes a printer head 20 as a droplet discharge unit, an inclination correction unit 30, and the like.
The conveyance unit 40 includes a supply unit 41, a storage unit 42, a conveyance roller 43, a platen 44, and the like, and the print medium 5 is arranged in the sub-scanning direction (Y-axis direction shown in FIG. 1) as a “first direction”. It can be moved (conveyed).
The scanning moving unit 50 includes a carriage 51, a guide shaft 52, a carriage motor (not shown), and the like, and scans the printer head 20 as a “second direction” that intersects the sub-scanning direction (first direction). It can be moved in the direction (X-axis direction shown in FIG. 1).

The printer head (droplet discharge unit) 20 has a plurality of nozzles (nozzle rows) that discharge printing ink (hereinafter referred to as ink) as droplets (hereinafter also referred to as ink droplets). The printer head 20 is mounted on a carriage 51 and reciprocates in the scanning direction with the carriage 51 moving in the scanning direction. A row of dots along the scanning direction is formed on the printing medium 5 by ejecting ink droplets onto the printing medium 5 supported by the platen 44 under the control of the controller 60 while the printer head 20 moves in the scanning direction. Is done.
The configuration of the printer head 20 will be described later.

  As the ink, for example, as an ink set made of a dark ink composition, a four-color ink set obtained by adding black (K) to a three-color ink set of cyan (C), magenta (M), and yellow (Y), etc. There is. Further, for example, eight colors including ink sets such as light cyan (Lc), light magenta (Lm), light yellow (Ly), and light black (Lk) made of a light ink composition in which the density of each color material is lightened. There are ink sets.

As a method for ejecting ink droplets (inkjet method), a piezo method is used as a preferred example. The piezo method is a method in which a pressure corresponding to a print information signal is applied to ink stored in a pressure chamber by a piezoelectric element (piezo element), and ink droplets are ejected (discharged) from a nozzle communicating with the pressure chamber for printing.
The method for ejecting ink droplets is not limited to this, and other recording methods for ejecting ink into droplets to form dot groups on a print medium may be used. For example, pressure is applied to the ink with a small pump and the nozzle is mechanically vibrated with a quartz crystal vibrator, etc. to forcibly eject ink droplets. A method of jetting and recording a droplet (thermal jet method) may be used.

  The guide shaft 52 extends in the scanning direction and supports the carriage 51 in a slidable contact state, and the carriage motor serves as a drive source for reciprocating the carriage 51 along the guide shaft 52. That is, the scanning moving unit 50 (carriage 51, guide shaft 52, carriage motor) moves the carriage 51 (that is, the printer head 20) in the scanning direction along the guide shaft 52 under the control of the controller 60.

The supply unit 41 rotatably supports a reel on which the print medium 5 is wound in a roll shape, and sends the print medium 5 to the transport path. The storage unit 42 rotatably supports a reel around which the print medium 5 is wound, and winds up the print medium 5 that has been printed from the conveyance path.
The conveyance roller 43 includes a driving roller that moves the printing medium 5 in the sub-scanning direction, a driven roller that rotates as the printing medium 5 moves, and the like. The conveyance path for conveying to the storage section 42 via the upper surface 44 and the area where the printer head 20 scans and moves is configured.

The controller 60 includes an interface unit 61, a CPU 62, a memory 63, a drive control unit 64, and the like, and controls the printer 100.
The interface unit 61 transmits and receives data between the PC 110 and the printer 100.
The CPU 62 is an arithmetic processing device for controlling the entire printer 100.
The memory 63 is a storage medium that secures an area for storing a program for the CPU 62 to operate, an operation area for the operation, and the like, and includes a storage element such as a RAM or an EEPROM.
The CPU 62 controls each drive unit (printing unit 10, transport unit 40, scan moving unit 50) via the drive control unit 64 according to the program stored in the memory 63 and the print data received from the PC 110.

  The controller 60 alternately repeats a droplet discharge operation for discharging ink from the printer head 20 moving in the scanning direction and a transport operation for moving the printing medium 5 in the sub-scanning direction, and is an image composed of a plurality of dots. Is printed on the print medium 5. The droplet discharge operation is sometimes referred to as “pass”.

<Basic functions of the printer driver>
Printing on the print medium 5 is started when print data is transmitted from the PC 110 connected to the printer 100. The print data is generated by the printer driver. Hereinafter, processing by the printer driver will be described with reference to FIG. FIG. 3 is an explanatory diagram of print data generation processing by the printer driver.

The printer driver receives image data (for example, text data or full-color image data) from the application, converts the print data into a format that can be interpreted by the printer 100, and outputs the print data to the printer 100. When converting image data from an application into print data, the printer driver performs resolution conversion processing, color conversion processing, halftone processing, rasterization processing, command addition processing, and the like.
Further, the printer driver has a function of performing a nozzle position correction process that characterizes this embodiment. The nozzle position correction process will be described later.

The resolution conversion process is a process of converting the image data output from the application into a resolution (print resolution) when printing on the print medium 5. For example, when the print resolution is specified as 720 × 720 dpi, the vector format image data received from the application is converted into bitmap format image data with a resolution of 720 × 720 dpi. Each pixel data of the image data after the resolution conversion process is composed of pixels arranged in a matrix. Each pixel has a gradation value of, for example, 256 gradations in the RGB color space. That is, the pixel data after resolution conversion indicates the gradation value of the corresponding pixel.
Pixel data corresponding to one column of pixels arranged in a predetermined direction among pixels arranged in a matrix is called raster data. The predetermined direction in which the pixels corresponding to the raster data are arranged corresponds to the moving direction (scanning direction) of the printer head 20 when printing an image.

The color conversion process is a process for converting RGB data into data in a CMYK color system space as an ink color space used by the printer 100. The CMYK colors are cyan (C), magenta (M), yellow (Y), and black (K), and the image data in the CMYK color system space is data corresponding to the ink color that the printer 100 has. Therefore, for example, when the printer 100 uses 10 types of inks of the CMYK color system, the printer driver generates image data in a 10-dimensional space of the CMYK color system based on the RGB data.
This color conversion processing is performed based on a table (color conversion lookup table LUT) in which gradation values of RGB data and gradation values of CMYK color system data are associated with each other. Note that the pixel data after the color conversion processing is, for example, CMYK color system data of 256 gradations represented by the CMYK color system space.

The halftone process is a process of converting high gradation number (256 gradations) data into gradation number data that can be formed by the printer 100. By this halftone processing, data indicating 256 gradations is converted into 1-bit data indicating 2 gradations or 2-bit data indicating 4 gradations. The image data after halftone processing is 1-bit or 2-bit data, and this pixel data is data indicating dot formation (the presence or absence of dots, the size of dots) in each pixel.
For example, in the case of 2 bits (4 gradations), no dot corresponding to the dot gradation value [00], formation of a small dot corresponding to the dot gradation value [01], and medium corresponding to the dot gradation value [10] It is converted into four stages like dot formation and large dot formation corresponding to the dot gradation value [11]. Thereafter, after the dot generation rate is determined for each dot size, pixel data is created so that the printer 100 forms the dots in a dispersed manner by using a dither method, γ correction, error diffusion method, or the like. .

  The rasterizing process is a process of rearranging pixel data arranged in a matrix according to the dot formation order at the time of printing. For example, when the dot formation process is performed several times during printing, pixel data corresponding to each dot formation process is extracted and rearranged according to the order of the dot formation process. In addition, since the dot formation order at the time of printing differs if the printing method is different, rasterization processing is performed according to the printing method.

  The command addition process is a process for adding command data corresponding to the printing method to the rasterized data. The command data includes, for example, conveyance data indicating the medium conveyance speed.

<Configuration of Printer Head 20>
FIG. 4 is a plan view showing the configuration of the printer head 20.
The printer head 20 includes the above-described eight inks (cyan (C), magenta (M), yellow (Y), black (K), light cyan (Lc), light magenta (Lm), light yellow (Ly), and light. The eight ink discharge heads 13 corresponding to black (Lk) are configured as an aggregate in which a base 15 is bundled in parallel.
In each ink discharge head 13, two nozzle chips 14 are arranged in two rows in a predetermined direction, two in a zigzag arrangement. Here, the distance between the nozzle chips 14 adjacent in the scanning direction (second direction) is Dx, and the distance between the nozzle chips 14 adjacent in the predetermined direction is Dy.
In the nozzle chip 14, two rows of nozzles 16 each having 10 holes are formed in a predetermined direction at intervals of 360 per inch.

  By mounting the printer head 20 having such a configuration on the carriage 51 so that the predetermined direction is perpendicular to the scanning direction (second direction, X-axis direction), 720 pitches per inch (720 dpi). ), It is possible to form 74 eight-color dots in the sub-scanning direction (Y-axis direction).

FIG. 5 is a plan view illustrating a relationship between a part of the ink discharge head 13 and a dot position formed by the discharged ink.
Since the two nozzle rows formed on the nozzle chip 14 are arranged with their positions in a predetermined direction shifted by a half pitch, the inter-column distance dp between dots formed on the print medium 5 is about 35. 3 μm (720 dpi). The difference in the position of the nozzles 16 in the scanning direction (second direction) can be regarded as a nozzle row virtually aligned in a predetermined direction by adjusting the timing of ejecting ink while scanning. Further, only one of the nozzles 16 (# 19A and # 20A and # 19B and # 20B nozzles 16 shown in FIG. 5) in the overlapping position in the scanning direction is effective.
The printer 100 forms an image corresponding to the image data on the print medium 5 by repeating the path of ejecting ink from the corresponding nozzle according to the raster data based on the print data generated from the image data.

  The configuration of the printer head 20 is not limited to such a small configuration. For example, each of the ink ejection heads 13 may have a configuration in which several tens to several hundreds of nozzle chips 14 are mounted, and each nozzle chip 14 has several hundreds of nozzles formed in several rows. . In the case of such a large-scale printer head 20, as shown in FIG. 6, a slight distortion may occur in the base body 15 that bundles the ink ejection heads 13. Specifically, the ink discharge heads 13 extending in a predetermined direction bundled in parallel have an inclination θ with respect to a direction orthogonal to the scanning direction (second direction, X-axis direction). Is the case.

When such an inclination occurs, the density difference of the formed dots is generated, and a portion where the overlap is dense becomes a dark streak and a portion where the overlap is coarse becomes a thin streak.
Therefore, the droplet discharge device 1 according to the present embodiment includes a unit that detects the inclination θ, an inclination correction unit 30 that corrects the inclination, and a nozzle that discharges droplets based on the correction amount corrected by the inclination correction unit. And a nozzle position correction processing function for correcting the position.
This will be specifically described below.

<Measuring means for inclination θ>
The inclination θ is detected by printing a predetermined image (an inclination θ detection image) on the printing medium 5 by using the printing function of the printer 100 and observing the image. In other words, the inclination θ detection means has a function of printing an inclination θ detection image and a function of deriving the inclination θ by observing the image.
The function of printing the image for detecting the inclination θ can be provided as a utility function of the printer driver.
The function for deriving the inclination θ can be automatically calculated by providing a scanner function for recognizing an image for detecting the inclination θ and an image processing function. Instead of providing the printer 100 with the function of deriving the inclination θ, a method in which the user of the printer 100 derives it by directly measuring the printed inclination θ detection image.

FIG. 7 shows an example of an inclination θ detection image printed for detecting the inclination θ. (Note that FIG. 6 is a plan view of the printer head 20 as viewed from below, whereas FIG. 7 is a view of the print surface, so the inclination is reversed.)
First, in a state where the printer head 20 is stationary with respect to the print medium 5, ink is ejected from all the nozzles 16 to form first dot rows 71 arranged in a predetermined direction on the print medium 5.
Next, while moving the printer head 20 in the scanning direction (second direction), a specific nozzle 16 (in the example of FIG. 7, # 12A shown in FIG. 5 of each nozzle chip 14 of the + X end ink discharge head 13). Ink is ejected from the nozzles 16) at position # 22A and the second dot row 72 aligned in the scanning direction (second direction) is formed on the print medium 5.

An inclination θ in a predetermined direction with respect to a direction orthogonal to the scanning direction (second direction) can be obtained from the angle formed by the formed first dot row 71 and second dot row 72. Specifically, for example, the center of gravity position of the dot group formed by the nozzle 16 of each nozzle chip 14 is obtained by image processing of the image captured by the scanner, and the first dot is obtained from the center of gravity of two points separated in a predetermined direction. The direction of the row 71 is obtained, and then the inclination θ is calculated based on the direction of the second dot row 72.
In the example shown in FIG. 7, by measuring the deviation x in the scanning direction (second direction) of the center of gravity of the dot group formed by the nozzles 16 of the nozzle chips 14 adjacent in a predetermined direction,
sin θ = x / Dy
Indicates that θ is calculated.
In addition, since the value of x measured from the center of gravity of two points separated in a predetermined direction has variation, it is preferable to calculate θ based on an average value of x, for example.

<Inclination correction unit 30>
FIG. 8 is a plan view illustrating an example of the configuration of the inclination correction unit 30.
The inclination correction unit 30 includes a plate 31, an adjustment dial 32, a worm gear mechanism 33, and the like.
The plate 31 is attached to the lower surface of the carriage 51 so as to be rotatable in the XY plane by a fulcrum F, and can be fixed to the carriage 51 by screws 34 provided at corner portions of the plate 31. The printer head 20 is fixed to the lower surface of the plate 31.
The adjustment dial 32 is a dial that rotates the worm portion of the worm gear mechanism 33 that connects the plate 31 and the adjustment dial 32. By rotating the dial value corresponding to the inclination θ, the plate 31 (that is, the printer head 20) can be rotated in the XY plane to correct the inclination θ. The adjustment dial 32 may be rotated automatically by a motor controlled by the controller 60 and automatically adjusted, or may be adjusted by the user of the printer 100.

FIG. 9 is a plan view showing a state in which the inclination θ is corrected.
The inclination correction unit 30 corrects the predetermined direction so as to face the direction orthogonal to the scanning direction (second direction). This correction eliminates or suppresses the density difference between the dots to be formed, thereby eliminating or suppressing the dark streak in the part where the overlap is dense and the thin streak in the part where the overlap is coarse. However, as shown in FIG. 9, by performing this correction, the position of the nozzle tip 14 is shifted in the first direction. When this positional deviation amount between the nozzle chips 14 adjacent in the scanning direction (second direction) is y, the deviation of the nozzle chips 14 at both ends is 7y as shown in FIG. This deviation degrades the quality of the image to be formed depending on the size of the deviation.

<Nozzle position correction processing function>
The nozzle position correction process is a function that eliminates or suppresses a nozzle position shift that occurs by correcting the inclination θ. The nozzle position correction process is performed by the printer control unit 111 (specifically, a printer driver). ) Is provided as part of its function.

FIG. 10 shows an example of an image obtained by printing an inclination θ detection image on the print medium 5 by means of detecting the inclination θ after correcting the inclination θ.
As is apparent from the figure, the positional deviation amount y in the predetermined direction of the nozzle chips 14 adjacent in the scanning direction (second direction) is
y = Dx · sinθ
Obtained by.
Therefore, when trying to eliminate all the positional deviations between the adjacent nozzle tips 14,
7y = 7Dx · sinθ
It is necessary to correct the deviation.

The positional deviation of the nozzle chip 14 is corrected by a method of correcting the position of the nozzle 16 that ejects ink based on the raster data described above. That is, the position of the nozzle 16 corresponding to the raster data is shifted by the correction amount.
The inter-row distance between dot rows formed in one pass is dp as shown in FIG. Therefore, in correcting the positional deviation between the adjacent nozzle tips 14,
Dx · sinθ / dp
The nozzle position is corrected by a natural number obtained by rounding off the value of the quotient obtained in step (b).

FIG. 11 is a plan view for explaining an example of the printer head 20 subjected to the nozzle position correction process.
Raster data assigned to the nozzles 16 in the region A where a deviation in a predetermined direction caused by correcting the inclination θ is recognized is shifted to the nozzles 16 in the −Y direction. Further, raster data that cannot be printed in the same pass after shifting and raster data assigned to the nozzles 16 in the region B are configured as raster data in the next pass.
As a result, the printer head 20 can be configured to have the configuration of the printer head 20 that has no deviation between the predetermined direction and the first direction and virtually does not have the nozzles 16 in the region A and the region B.
In addition, it is not a configuration without the nozzles 16 in the region A and the region B, but is a method of overlapping and using in the front and rear passes (the front and rear passes performed by moving the print medium 5 in the sub-scanning direction). Also good.

As described above, according to the droplet discharge device and the adjustment method of the droplet discharge device according to the present embodiment, the following effects can be obtained.
When a predetermined direction in which a plurality of nozzles 16 constituting each of a plurality of nozzle rows arranged in the scanning direction (second direction) is inclined with respect to a direction orthogonal to the scanning direction (second direction) The tilt is corrected. Further, based on this correction amount, the position of the nozzle 16 that ejects ink is corrected. As a result, the plurality of nozzle rows arranged in the scanning direction (second direction) can form dots arranged in the sub-scanning direction (first direction). In addition, since the position of the nozzle 16 that ejects ink is corrected with respect to the nozzle 16 whose position changes in the direction orthogonal to the scanning direction (second direction) by the correction of the inclination, the inclination given to the formed image The influence of the correction can be suppressed.

  Further, the position of the nozzle 16 that ejects ink is corrected based on a value calculated by Dx · sin θ / dp. The value of Dx · sin θ is such that the position of the nozzle row adjacent in the scanning direction (second direction) fluctuates in the direction orthogonal to the scanning direction (second direction) due to the correction of the inclination. This size and dp (distance between a plurality of dot rows formed in the scanning direction (second direction) by the ink ejected while the nozzle row is scanned and moved in the scanning direction (second direction). The position of the nozzle 16 that ejects ink is corrected based on the value of the ratio between the second direction) and the interval between the positions of the nozzles 16 in the direction orthogonal to the second direction. A suitable correction can be performed by shifting the position of the nozzle 16 that discharges by a natural number obtained by rounding off the ratio value (quotient).

Further, by observing the angle formed between the first dot row 71 and the second dot row 72 formed on the print medium 5, the amount to be corrected can be easily obtained.
The description will be made on the assumption that the inclination θ of the plurality of nozzle arrays arranged in the second direction and the distance Dx between the nozzle arrays have substantially the same value in any of the ink ejection heads 13 in the above embodiment. However, the present invention is not limited to this, and the present invention can be applied even when there is a variation in the inclination θ and the nozzle row distance Dx, and has the same effect as the above embodiment.
When the plurality of ink discharge heads 13 have different θs, the respective inclinations θ are measured, and the average value or the median value thereof is handled as the inclination θ of the above embodiment.
Regarding the Dx of the distance between adjacent nozzle rows, it is possible to use one Dx as the average value or the median value of the entire measured values, but the distance Dx between the nozzle rows between the adjacent ink ejection heads 13 is determined individually. If applied, the effect of the present invention becomes greater.

  DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 5 ... Printing medium, 10 ... Printing part, 13 ... Ink discharge head, 14 ... Nozzle chip, 15 ... Base | substrate, 16 ... Nozzle, 20 ... Printer head, 30 ... Tilt correction part, 31 ... Plate 32 ... Adjustment dial 33 ... Worm gear mechanism 34 ... Screw 40 ... Conveying unit 41 ... Supply unit 42 ... Storage unit 43 ... Conveying roller 44 ... Platen 50 ... Scanning moving unit 51 ... Carriage 52 ... guide shaft, 60 ... controller, 61 ... interface unit, 62 ... CPU, 63 ... memory, 64 ... drive control unit, 71 ... first dot row, 72 ... second dot row, 100 ... inkjet printer (printer), 110 ... Personal computer (PC), 111 ... Printer control unit, 112 ... Input unit, 113 ... Display unit, 114 ... Storage unit.

Claims (5)

A transport unit that moves the print medium in the first direction;
A liquid droplet ejection unit having a plurality of nozzle rows composed of a plurality of nozzles arranged in a predetermined direction for ejecting liquid droplets on the print medium;
A method of adjusting a droplet discharge device comprising: a scan moving unit that scans and moves the droplet discharge unit in a second direction,
Correcting the inclination of the predetermined direction with respect to the first direction within a plane including the first direction and the second direction;
An adjustment method for a droplet discharge device, wherein the position of the nozzle that discharges the droplet is corrected based on the corrected correction amount. The correction amount is θ,
The distance in the second direction between the adjacent nozzle rows is Dx,
When the distance between rows of a plurality of dot rows formed in the second direction by the droplets ejected while the nozzle row is scanned and moved in the second direction is dp,
2. The method of adjusting a droplet discharge device according to claim 1, wherein the position of the nozzle that discharges the droplet is corrected based on a value calculated by Dx · sin θ / dp. Forming the first dot row aligned in the predetermined direction on the print medium by ejecting the liquid droplets from the nozzle in a state where the liquid droplet ejection unit is stationary with respect to the print medium;
Forming the second dot row aligned in the second direction on the print medium by discharging the droplet from the specific nozzle while scanning and moving the droplet discharge section in the second direction;
The method according to claim 1, further comprising: obtaining an inclination of the predetermined direction with respect to the first direction from an angle formed by the first dot row and the second dot row. Method for adjusting droplet discharge device. A transport unit that moves the print medium in the first direction;
A droplet discharge section having a plurality of nozzle rows each composed of a plurality of nozzles arranged in a predetermined direction for discharging droplets to the print medium;
A scanning movement unit that scans and moves the plurality of nozzle rows in the second direction;
An inclination correction unit capable of correcting an inclination of the predetermined direction with respect to the first direction in a plane including the first direction and the second direction;
And a controller that corrects a position of the nozzle that discharges the droplet based on a correction amount corrected by the inclination correction unit. The correction amount is θ,
The distance in the second direction between the adjacent nozzle rows is Dx,
When the distance between rows of a plurality of dot rows formed in the second direction by the droplets ejected while the nozzle row is scanned and moved in the second direction is dp,
5. The droplet discharge device according to claim 4, wherein the control unit corrects the position of the nozzle that discharges the droplet based on a value calculated by Dx · sin θ / dp.

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