JP2010214622A - Printing method, printing apparatus, and test pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test pattern optimum for detection of a gap so as to correct synthetically or on average on the whole paper surface the gap of a printing result possibly generated at each position on the paper, and to provide a printing method and a printing apparatus in which the pattern can be printed. <P>SOLUTION: In the printing method, a predetermined pattern is printed by delivering an ink onto a printing medium from the nozzles of an ink delivering section using the printing apparatus which includes the ink delivering section wherein a plurality of nozzle arrays with a plurality of nozzles arranged in a first direction are aligned in parallel. A ruled line pattern comprised of a combination of a plurality of ruled lines which are expressed in the ink delivered from nozzles by delivering the ink from the nozzles that belong to different nozzle arrays and which are nearly directed to a second direction orthogonal to the first direction is printed onto a plurality of points on the printing medium. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing method, a printing apparatus, and a test pattern.

  Inkjet printers that form images by ejecting ink onto paper have been used. Such a printer performs printing by ejecting ink from the nozzles while relatively changing the positional relationship between the paper and a print head having a nozzle row in which the nozzles are arranged. Here, it is ideal that the paper always maintains a certain angle with respect to the direction (specific direction) in which the relative positional relationship between the print head and the paper changes when ink is ejected from the nozzles. Specifically, the printer fixes a print head having a nozzle row having a length corresponding to the paper width of the paper, and prints for the paper width with the direction perpendicular to the direction of the nozzle row of the print head as the paper transport direction. In the case of a so-called line head type printer that performs printing at a time, it is ideal that the paper be transported in parallel with the transport direction (specific direction).

Alternatively, the printer has a print head that discharges ink in accordance with movement in the main scanning direction, and the direction perpendicular to the main scanning direction is set as the paper conveyance direction, and the movement of the print head and the conveyance of the paper are alternately repeated. In the case of a so-called serial type printer that performs printing in this way, it is ideal that the paper is conveyed perpendicularly to the main scanning direction (specific direction).
However, in the printer, when there is a paper transport accuracy error (a transport accuracy error in which the paper is slightly meandered and transported), it is difficult to keep the paper angle constant with respect to the specific direction. Become.

JP 7-256933 A JP 7-81190 A JP-A-8-324012 Japanese Patent Laid-Open No. 2003-39646

  As described above, when the angle of the sheet is not constant with respect to the specific direction, the relative angle between the print head and the sheet slightly changes according to the conveyance of the sheet. In other words, when printing on the paper in the printer, the relative angle between the print head and the paper during printing differs for each position on the paper. Such a difference in the relative angle between the print head and the paper appears as a deviation between printing results for each nozzle on the paper, and such a deviation appears in different degrees and directions depending on the position on the paper. Conventionally, it has been difficult to comprehensively or averagely correct the deviation of the printing result that may occur at each position on the paper. In addition, in order to comprehensively or averagely correct such a deviation in printing results over the entire sheet, an optimum test pattern is required for detecting such deviation.

  The present invention has been made in view of the above problems, and is used to comprehensively or averagely correct a deviation in printing results that may occur at each position on a printing medium due to a conveyance accuracy error of the printing medium. An object is to provide an optimum test pattern, a printing method and a printing apparatus capable of printing the pattern.

  In order to achieve the above object, the present invention uses a printing apparatus including an ink ejection unit in which a plurality of nozzle rows in which a plurality of nozzles are arranged in a first direction are arranged in parallel, from the nozzle of the ink ejection unit to the print medium. A printing method for printing a predetermined pattern by ejecting ink, and a plurality of ruled lines represented by ink ejected from each nozzle by ejecting ink from each nozzle belonging to different nozzle rows In this configuration, a ruled line pattern composed of a combination of a plurality of ruled lines substantially facing a second direction orthogonal to the first direction is printed at a plurality of locations on the print medium. According to the present invention, for each ruled line pattern printed on the print medium, the positional relationship between the ruled lines constituting the ruled line pattern is observed by a machine or artificially, thereby easily shifting the print result at each location on the print medium. And it can detect reliably. That is, when correcting the deviation of the printing result at each location of the printing medium in a comprehensive or average manner, an optimum pattern can be obtained by using the deviation detection.

  In the printing method, the plurality of ruled lines are substantially combed along the first direction by ejecting ink from the nozzles that belong to different nozzle rows and are separated in the first direction. A ruled line pattern arranged in a tooth shape may be printed. According to the configuration, by observing whether the ruled lines constituting the ruled line pattern are arranged in a comb-teeth shape or whether the comb-teeth shape is broken (how it is broken) or the like, It is possible to easily and reliably detect the deviation of the printing result.

  In the printing method, a ruled line pattern in which the plurality of ruled lines are substantially continuous is printed by ejecting ink from nozzles belonging to different nozzle rows and having the same position in the first direction. You may do that. According to this configuration, printing at each location on the print medium is performed by observing whether the ruled lines constituting the ruled line pattern are continuously linear or whether the linearity is broken (how it is broken). The deviation of the result can be detected easily and reliably.

  In the above printing method, a ruled line pattern composed of a combination of ruled lines of the same color may be printed by ejecting the same color of ink from each nozzle that ejects the same color of ink. According to this configuration, by observing the positional relationship between the ruled lines of the same color that configure the ruled line pattern, it is possible to easily and reliably detect the deviation of the print result at each location on the print medium.

  In the printing method described above, a ruled line pattern composed of a combination of ruled lines of different colors may be printed by ejecting ink of different colors from each nozzle that ejects ink of different colors. According to this configuration, by observing the positional relationship between the ruled lines of different colors constituting the ruled line pattern, it is possible to easily and reliably detect the deviation of the print result at each location on the print medium.

  The technical idea of the present invention can be realized by methods other than the printing method. For example, it is possible to grasp an invention of a printing apparatus that executes processing executed in the printing method, and an invention of a printing program that causes a computer to execute processing executed in the printing method. Further, the pattern itself printed by the above printing method can be regarded as one invention. In other words, printing is performed by ejecting ink from the nozzles of the ink ejection unit to the printing medium using a printing apparatus including an ink ejection unit in which a plurality of nozzle rows in which a plurality of nozzles are arranged in the first direction are arranged in parallel. A plurality of ruled lines expressed by ink ejected from the nozzles belonging to different nozzle rows and perpendicular to the first direction. A printed test pattern can be grasped as one invention by arranging ruled line patterns composed of a combination of a plurality of ruled lines substantially directed in directions at a plurality of locations on the print medium.

  Further, based on each shift at each location of the print medium detected from the printed pattern as described above, an adjustment value for correcting each shift is averaged, and the printing apparatus is based on the calculated adjustment value. By performing a predetermined adjustment process (adjustment of the attachment angle and position of the ink ejection unit) on the sheet, it is possible to comprehensively and averagely correct the deviation of the printing result generated at each position of the sheet over the entire sheet. .

It is a block diagram showing a printer adjustment system. FIG. 4 is a diagram illustrating a relationship between a sheet and an ink discharge unit when the printer is a line head type. FIG. 4 is a diagram illustrating a relationship between a sheet and an ink discharge unit when the printer is a serial type. It is the flowchart which showed the inclination adjustment process. FIG. 4 is a diagram illustrating an example of a print head as an ink discharge unit. 6 is a diagram illustrating an example of a relationship between a print head and a test pattern in Embodiment 1. FIG. 6 is a diagram illustrating another example of the relationship between the print head and the test pattern in Embodiment 1. FIG. It is the figure which expanded and illustrated the relationship between the nozzle row used for printing of a ruled line pattern, and a ruled line pattern. FIG. 6 is a diagram illustrating another example of a print head serving as an ink ejection unit. 6 is a diagram illustrating an example of a relationship between a print head and a test pattern in Embodiment 2. FIG. FIG. 10 is a diagram illustrating another example of the relationship between the print head and the test pattern in the second embodiment. FIG. 4 is a diagram illustrating an example of a print head unit as an ink discharge unit. 10 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Embodiment 3. FIG. FIG. 10 is a diagram illustrating another example of a relationship between a print head unit and a test pattern in Embodiment 3. FIG. 10 is a diagram illustrating another example of a relationship between a print head unit and a test pattern in Embodiment 3. FIG. 10 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Embodiment 4. FIG. 10 is a diagram illustrating another example of a relationship between a print head unit and a test pattern in Example 4. FIG. 10 is a diagram illustrating another example of a relationship between a print head unit and a test pattern in Example 4. FIG. 4 is a diagram illustrating a print head unit group as an ink discharge unit. FIG. 10 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Example 6. FIG. 6 is a diagram illustrating another example of a print head unit as an ink discharge unit. It is the flowchart which showed the vertical alignment adjustment process. FIG. 10 is a diagram illustrating an example of a relationship between a print head unit group and a test pattern in Example 8. FIG. 10 is a diagram illustrating an example of a relationship between a print head unit group and a test pattern in Example 9. FIG. 10 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Example 10. FIG. 15 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Example 11. 5 is a flowchart illustrating a print timing adjustment process. FIG. 20 is a diagram illustrating an example of a relationship between a print head and a test pattern in Example 14. FIG. 17 is a diagram illustrating an example of a relationship between a print head and a test pattern in Example 15. FIG. 20 is a diagram illustrating an example of a relationship between a print head and a test pattern in Example 16. FIG. 18 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Example 17. FIG. 19 is a diagram illustrating an example of a relationship between a print head unit and a test pattern in Example 18. FIG. 20 is a diagram illustrating an example of a relationship between a print head unit group and a test pattern in Example 19. FIG. 20 is a diagram illustrating an example of a relationship between a print head unit group and a test pattern in Example 20. It is the figure which showed the example of the test pattern. It is the figure which showed the example of the test pattern.

1. FIG. 1 is a block diagram showing a printer adjustment system 60 (system 60) for realizing printer adjustment processing according to the present embodiment. The system 60 generally includes a computer 10, a printer 20, and a scanner 30. The printer 20 includes at least a paper transport unit 21, an ink discharge unit 22, a controller 23, an interface (I / F) 24, and a drive signal generation circuit 25. The printer 20 is a printing apparatus that implements the printing method of the present invention. In addition, the system 60 appropriately includes a jig 50 (chain line) for automatically adjusting the ink ejection unit 22 and the like.

  The computer 10 functions as a control device for the printer 20. The printer 20 receives print data from the computer 10 via the I / F 24. Then, based on the received data, the controller 23 of the printer 20 controls each part of the printer 20 (the paper transport unit 21, the ink discharge unit 22, and the drive signal generation circuit 25), and the image on the paper S (a kind of print medium). To print. A scanner 30 is connected to the computer 10. The scanner 30 can scan the print image on the paper S printed by the printer 20, and transfers the image data acquired by the scan to the computer 10.

The paper transport unit 21 is a device for transporting the paper S in a predetermined direction (transport direction). The paper transport roller (not shown), a paper transport roller, a motor for rotating each roller, and a span between the rollers. Necessary mechanisms such as a transporting belt are provided as appropriate.
The ink discharge unit 22 is a mechanism in which a plurality of nozzle rows configured by arranging a plurality of nozzles in a certain direction are arranged in parallel, and ink droplets (dots) of a predetermined color from the nozzles on the facing paper S. Can be discharged. The direction in which the nozzles constituting one nozzle row are arranged is referred to as the nozzle row direction.

  A unit configured by arranging a predetermined number of nozzle rows in parallel is called a print head. A unit configured by arranging a predetermined number of print heads in a predetermined arrangement pattern along the nozzle row direction is referred to as a print head unit. A unit configured by arranging a predetermined number of print head units in a predetermined arrangement pattern along a direction orthogonal to the nozzle row direction is referred to as a print head unit group. The ink ejection unit 22 may be any of a print head, a print head unit, and a print head unit group.

  FIG. 2 simply shows the relationship between the paper S transported by the paper transport unit 21 and the ink ejection unit 22 from the viewpoint from above the printer 20. In FIG. 2, it is assumed that the printer 20 is a line head type model, and the ink ejection unit 22 whose length in the nozzle row direction covers the paper width W of the paper S is illustrated. The ink discharge unit 22 as such a line head is fixed in the printer 20 (however, the inclination and position can be adjusted). In FIG. 2, a direction substantially orthogonal to the nozzle row direction of the ink discharge unit 22 is a transport direction. Accordingly, the sheet S is basically transported along the transport direction, and receives ink ejection from the ink ejection section 22 when passing under the ink ejection section 22.

  FIG. 3 shows the relationship between the paper S transported by the paper transport unit 21 and the ink ejection unit 22, and simply shows an example different from FIG. 2 from the viewpoint from the top of the printer 20. In FIG. 3, it is assumed that the printer 20 is a serial type model, and the ink ejection unit 22 whose length in the nozzle row direction covers only a part of the paper S is illustrated. In the configuration of FIG. 3, the ink ejection unit 22 basically moves in a direction (main scanning direction) orthogonal to the nozzle row direction by a carriage mechanism (not shown), and ejects ink along with the movement. In addition, the paper transport unit 21 uses a direction orthogonal to the main scanning direction as the transport direction. In the configuration of FIG. 3, the ink on the paper S under the movement path of the ink ejection unit 22 is alternately repeated by conveying a predetermined amount of the paper S and moving (reciprocating) the ink ejection unit 22 in the main scanning direction. Discharge is performed. The printer 20 used in this embodiment may be either a line head type or a serial type.

The controller 23 is a control unit that controls the entire printer 20 and performs arithmetic processing for control. The controller 23 is connected to the I / F 24 and can communicate with the computer 10. Further, the controller 23 includes a memory for storing programs and data. And each part is controlled according to the program stored in memory. The carriage mechanism is also controlled by the controller 23.
The drive signal generation circuit 25 is a circuit that generates a drive signal to be applied to the piezoelectric elements provided in the ink discharge unit 22 corresponding to each nozzle in order to discharge dots from the nozzle. The drive signal generation circuit 25 outputs a drive signal to the ink ejection unit 22 under the control of the controller 23.
The printer adjustment process of the present embodiment includes a “tilt adjustment process”, a “vertical alignment adjustment process”, and a “print timing adjustment process”. Hereinafter, each process will be described in order.

2. Inclination Adjustment Processing FIG. 4 is a flowchart showing the inclination adjustment processing of the ink ejection unit 22 executed by the system 60. In the tilt adjustment processing, a plurality of ruled lines represented by ink ejected from the nozzles by ejecting ink from the nozzles belonging to different nozzle rows included in the ink ejection unit 22 to be adjusted in the printer 20 A ruled line pattern composed of a combination of a plurality of ruled lines that are substantially oriented in the direction orthogonal to the nozzle row direction is printed as evenly as possible on the paper S (a test pattern in which the ruled line patterns are arranged uniformly is printed). Then, based on the position of the ruled line in each ruled line pattern, the attachment angle (tilt) of the ink discharge unit 22 as the adjustment target is adjusted. At the start of the tilt adjustment process, the ink ejection unit 22 is disposed at an angle (initial setting angle) that is somewhat ideal based on the relationship with the transport direction. In the printer adjustment process of the present embodiment, basically, a plurality of ruled line patterns are printed over the entire surface of the paper S. The entire surface of the paper S means an area on the paper S where the printer 20 can record. For example, when margins are set on the top, bottom, left and right of the paper S, it means an area excluding the margin.
Hereinafter, Examples 1 to 7 of the tilt adjustment process will be described based on the flowchart of FIG.

Example 1
FIG. 5 shows the ink ejection unit 22 to be adjusted in the first embodiment. In the first embodiment, the ink ejection unit 22 includes a single print head 22a. 9, 12, and 21 showing the ink discharge unit 22 including FIG. 5, an arrangement of nozzles (white circles) when the printer 20 is viewed from above is shown for easy understanding. In the print head 22a, a plurality of nozzle rows (a to h rows) are arranged in parallel. One nozzle row is for ejecting one kind of ink. As an example, the a and h rows are black (K) ink, the b and g rows are cyan (C) ink, and the c and f rows are magenta ( M) Ink and d, e rows are configured to eject yellow (Y) ink.

  Each of the rows a through h includes N nozzles. In each nozzle row, nozzle numbers # 1 to #N are assigned to the nozzles from one end side to the other end side in the nozzle row direction. The distance L between nozzles in a single nozzle row is, for example, 180 dpi. When a plurality of nozzle rows are viewed together, the nozzles are arranged in a staggered manner. That is, the nozzles with the same nozzle number belonging to the odd-numbered a, c, e, and g rows are formed at the same position in the nozzle row direction, and similarly, the same nozzles belonging to the even-numbered b, d, f, and h rows. Each nozzle of the nozzle number is formed at the same position in the nozzle row direction. Accordingly, when the entire print head is considered, the nozzles are arranged at L / 2 in the nozzle row direction. Hereinafter, the length of L / 2 is expressed as a nozzle pitch (P).

  The ink ejection unit 22 includes an angle adjustment plate 411 and an angle adjustment dial 412. The angle adjustment plate 411 is a plate that can rotate in a plane parallel to the transport surface of the paper S. The print head (print head 22a or print head 22b described later) and the angle adjustment plate 411 are connected to each other. When the angle adjustment plate 411 rotates, the entire print head rotates accordingly. The angle adjustment plate 411 rotates as the angle adjustment dial 412 rotates. The angle adjustment dial 412 has a scale not shown. The rotation amount of the angle adjustment plate 411 relative to the rotation amount of the angle adjustment dial 412 is obtained in advance, and the print head can be rotated by a desired angle using the angle adjustment dial 412 based on this relationship.

  The ink ejection unit 22 includes a translation plate 413 and a translation dial 414. The translation plate 413 is a plate that can move in the vertical direction within a plane parallel to the transport surface of the paper S. In the present embodiment, if the printer 20 is a serial type, the upstream side in the transport direction of the paper S is up, the downstream side in the transport direction is down, and the left and right are defined based on the top and bottom. On the other hand, if the printer 20 is a line head type, the upstream side in the transport direction of the paper S is on the left and the downstream side in the transport direction is on the right. The print head (print head 22a or print head 22b described later) and the translation plate 413 are connected to each other. When the translation plate 413 moves in the vertical direction, the entire print head moves in the vertical direction accordingly. The translation plate 413 moves as the translation dial 414 rotates. A scale not shown is engraved on the translation dial 414. Then, the amount of movement of the translation plate 413 relative to the amount of rotation of the translation dial 414 is obtained in advance, and the print head can be moved up and down by a desired distance using the translation dial 414 based on this relationship. The movement by the translation plate 413 is performed in a “vertical alignment adjustment process” described later.

In the configuration described above, in step S (hereinafter, “step” is omitted) 100, the system 60 prints the test pattern TP1 on a plurality of sheets S.
FIG. 6 simply illustrates the relationship between the test pattern TP1 printed on the paper S and the print head 22a in the first embodiment. In FIG. 6, it is assumed that the printer 20 is a serial type. The test pattern TP1 includes a plurality of ruled line patterns LP1 arranged on the paper S in the main scanning direction and the transport direction. The ruled line pattern LP1 is a pattern in which a plurality of ruled lines of the same color having a predetermined length substantially facing the main scanning direction are arranged in a comb-teeth shape substantially along the nozzle row direction. By the movement of the print head 22a in the main scanning direction (movement accompanied by ink ejection), a pattern row composed of a plurality of ruled line patterns LP1 arranged in the main scanning direction is printed. By repeating each time, the pattern row is repeatedly printed along the transport direction.

  FIG. 7 shows a relationship between the test pattern TP1 printed on the paper S and the print head 22a in the first embodiment, and shows an example different from FIG. In FIG. 7, it is assumed that the printer 20 is a line head type, and each nozzle row of the print head 22 a has a length corresponding to the paper width W of the paper S. Also in FIG. 7, the contents of the test pattern TP1 are the same as those shown in FIG.

  In the first embodiment, each ruled line constituting the ruled line pattern LP1 is printed by nozzles belonging to different nozzle rows in the print head 22a and corresponding to ink of the same color. Specifically, in the example of FIGS. 6 and 7, the ruled line pattern LP <b> 1 is configured by K ink ruled lines (K ruled lines) printed by the nozzles in the a and h columns that discharge K ink. As can be seen from FIG. 5, the positions of the nozzles in the a row and the nozzles in the h row are shifted from each other by P in the nozzle row direction. Therefore, the ruled lines printed by the nozzles in the a row and the ruled lines printed by the nozzles in the h row are basically arranged between each other, and as a result, a comb-like ruled line pattern LP1 is formed.

  In S100, the computer 10 generates (acquires) color image data (color image data in which each pixel is expressed by an ink gradation value) expressing the test pattern. Next, for color image data, halftone processing using a known method such as a dither method or an error diffusion method is performed, and halftone data that defines whether or not to eject dots for each pixel and each ink type is obtained. Generate. Further, the computer 10 performs a predetermined rasterization process on the halftone data, rearranges the data in the order in which the printer 20 prints, generates raster data for each ink type, and sequentially transmits the raster data (print data) to the printer 20. Output. As a result, in the printer 20, the paper transport unit 21, the drive signal generation circuit 25, and the ink ejection unit 22 are driven and controlled by the controller 23, and the test pattern based on the raster data is printed on the paper S.

  6 and 7, a blank is provided between the ruled line pattern LP1 and the ruled line pattern LP1 in the nozzle row direction, but a pattern in which ruled lines are continuously arranged may be printed without providing this blank. 6 and 7 and the test patterns printed in the following embodiments, the number of ruled lines is reduced for easy understanding, but the number of ruled lines actually printed is shown in the figure. is more than. Further, when a comb-like pattern such as the ruled line pattern LP1 is printed, it is necessary to use all the nozzles in the nozzle row used for printing (the a and h rows of the print head 22a if the ruled line pattern LP1 is printed). Alternatively, nozzles that exist in some degree in the nozzle row direction may be selected and used for printing. However, in this case, the positional relationship (for example, nozzles # 2, # 5, # 8... In the a row and nozzles in the h row are arranged in the middle position between the nozzles in one nozzle row and the nozzles in the other nozzle row). Nozzles # 1, # 4, # 7... Are selected from both nozzle rows and used.

  In S110, the system 60 performs evaluation based on a plurality of test patterns TP1 printed in the latest S100, and calculates an evaluation value. In the system 60, the test pattern TP1 printed on the plurality of sheets S is read one by one by the scanner 30, and the image data of each test pattern TP1 obtained by the reading is transferred from the scanner 30 to the computer 10. The computer 10 analyzes the transferred image data to evaluate the score for the test pattern TP1, and calculates the evaluation value.

  8A and 8B show an enlarged relationship between the ruled line pattern LP1 and the a and h columns used for printing the ruled line pattern LP1 in the print head 22a. In the print head 22a of FIGS. 8A and 8B, the nozzle rows other than the a and h rows are not shown. FIG. 8A shows an example in which the relative angle between the nozzle row direction and the paper S at the time of pattern printing is an ideal angle (in the case of the line head type printer 20, the paper S is conveyed perpendicularly to the nozzle row direction. In the case of the serial type printer 20, the ink ejection unit 22 is moving vertically with respect to the direction in which the paper S faces. On the other hand, FIG. 8B shows a case where the relative angle between the nozzle row direction and the paper S during pattern printing is not ideal and is inclined (particularly when the paper S is conveyed at an oblique angle with respect to the nozzle row direction). Is shown.

  As shown in FIG. 8A, when the relative angle is an ideal angle, the ruled line printed in the h row of the print head 22a (for example, the ruled line printed by the nozzle #n in the h column) is the ruled line. Is located substantially at the center between the ruled lines printed in the a row (the ruled lines printed by the nozzles # n-1 and #n in the a row). On the other hand, as shown in FIG. 8B, when the relative angle is inclined from the ideal angle, the ruled line printed in the h column is located at the center between the ruled lines printed in the a column that should originally sandwich the ruled line. They are not positioned and are shifted upward or downward, overlapped with the ruled lines to be sandwiched, and further shifted upward or below the ruled lines to be sandwiched.

  The deviation of the ruled line printed in the h row (a row) from the ruled line printed in the a row (h row) is mainly a subtle meander of the paper S when the paper S is conveyed by the paper conveying unit 21. caused by. Such a shift may also occur when the linearity of movement of the ink ejection unit 22 in the main scanning direction is not completely maintained in the serial type printer 20. Further, the degree and direction of such a shift differs depending on the position on the paper S. Therefore, the computer 10 analyzes the image data of the plurality of test patterns TP1, and is a ruled line constituting each ruled line pattern LP1 printed evenly on each sheet S, and is one of the nozzle rows used for printing. Each of the predetermined number of ruled lines printed by the nozzle row (for example, h row) is at the center position that should be originally between the ruled lines printed by the other nozzle row (a row), or is located above the center position. Or whether it is located below the center position.

  For example, the computer 10 gives “0 point” as a score to a ruled line evaluated as being in the center position, and gives “+1 point” to a ruled line evaluated as being located above the center position. Given, “−1 point” is given to the ruled line evaluated as being located below the center position. Then, all the points given to the predetermined number of ruled lines in this way are totaled, and the total score is set as an overall evaluation value for the test pattern TP1 printed on the plurality of sheets.

  In S120, the computer 10 determines whether or not the evaluation value calculated in the latest S110 is within a predetermined high evaluation range (0 points ± predetermined points), and the evaluation value is within the high evaluation range. Ends the flowchart of FIG. That is, if the evaluation value is 0 point or a value close to a predetermined value close to 0 point, even if there is a slight shift due to the meandering in the printing results at each position of the plurality of sheets S, the plurality of sheets S This is because it can be said that the ink discharge section 22 is attached at an appropriate angle that makes the influence of the shift feel the least when viewed as a whole. On the other hand, if the evaluation value is out of the high evaluation range, the computer 10 determines that the angle adjustment of the ink ejection unit 22 is necessary, and proceeds to S130.

  In S130, the computer 10 specifies the rotation amount of the ink ejection unit 22 corresponding to the evaluation value calculated in the latest S110. The computer 10 has, as information, a table or a function that defines a correspondence relationship between the evaluation value and the rotation amount in advance, and identifies the rotation amount that uniquely corresponds to the evaluation value with reference to the correspondence relationship. Here, for example, when the evaluation value is a positive value, the rotation amount is in the − direction (clockwise) according to the value. When the evaluation value is a negative value, the + direction (counterclockwise) according to the value is used. A correspondence relationship such as a clockwise rotation amount is defined.

  In S140, the system 60 adjusts the angle of the ink discharge unit 22 to be adjusted according to the rotation amount specified in the latest S130. As an example, the system 60 uses a predetermined jig 50 (see FIG. 1) for the adjustment. The jig 50 is connected to the computer 10 and is an apparatus that adjusts the angle and position of the ink discharge unit 22 (in the first embodiment, the print head 22a) in accordance with an instruction from the computer 10. That is, the computer 10 sends an angle adjustment command of the print head 22a according to the specified rotation amount to the jig 50, and the jig 50 receiving the command rotates the angle adjustment plate 411 according to the rotation amount. At this time, the jig 50 may be rotated by operating the angle adjustment dial 412 according to the amount of rotation, or the angle adjustment plate 411 may be directly rotated.

  After S140, the process returns to S100 again, and the processing from printing a plurality of test patterns TP1 is repeated. That is, the test pattern printing and the adjustment based on the printing result are repeated until the evaluation value converges within the high evaluation range. As a result, even if there is a conveyance error such as meandering on the paper S, the angle of the ink ejection unit 22 (print head 22a) is the angle at which the deviation of the print result due to the meandering is most difficult to be seen as a whole. Can be adjusted. Note that the characteristic of the meandering of the paper S is considered to occur repeatedly at a certain period due to the rotation characteristics of the rollers, motors, etc. of the paper transport unit 21. For this reason, in the inclination adjustment process, a plurality of test patterns are printed, and an evaluation value is obtained based on the printing result at each position of the plurality of test patterns. The angle of 22 is decided.

  In the present embodiment, some or all of the processes in S110 to S140 in FIG. 4 may be performed artificially. For example, the user may visually observe the test pattern printed in S100, and the user may score each ruled line. In this case, the user can perform processing after the calculation of the total value (evaluation value) on the computer 10 side by inputting the number of points attached to each ruled line to the computer 10. Alternatively, the user may perform processing up to the calculation of the total value (evaluation value) and input the calculated evaluation value to the computer 10. Alternatively, the user may perform processing up to the specification of the rotation amount and input the specified rotation amount to the computer 10. Alternatively, the user may adjust the angle of the ink discharge unit 22 by operating the angle adjustment dial 412 according to the rotation amount specified by the computer 10.

  The reason why the ruled line pattern LP1 is printed with K ink is that the two nozzle rows corresponding to K ink in the ink row of the print head 22a are in the farthest positional relationship in the direction orthogonal to the nozzle row. That is, by printing ruled lines with nozzle rows that are located as far as possible in the print head 22a, the relative angle deviation is likely to appear in the positional deviation between the ruled lines. In other words, regardless of K, as a color used for printing the ruled line pattern LP1, a color in which the two nozzle arrays are as far as possible in the print head 22a to be adjusted may be selected. The idea of using a nozzle row having a positional relationship as far as possible for printing a ruled line pattern is common to Examples 2 to 13 below.

Example 2
In Example 2 and other Examples 3 to 7, parts different from Example 1 will be described.
FIG. 9 shows the ink ejection unit 22 to be adjusted in the second embodiment. The ink discharge unit 22 used in the second embodiment is a single print head 22b. The order of the ink colors corresponding to the nozzle rows in the print head 22b is different from that of the print head 22a. In the print head 22b, columns a and b correspond to K ink, columns c and d correspond to C ink, columns e and f correspond to Y ink, and columns g and h correspond to M ink. In S100, the system 60 prints the test pattern TP2 on the plurality of sheets S by the printer 20.

  FIG. 10 simply illustrates the relationship between the test pattern TP2 printed on the paper S and the print head 22b in the second embodiment. The solid line print head 22b is a serial type, and the two-dot chain line print head 22b is a line head type. The test pattern TP2 includes a plurality of ruled line patterns LP2. The ruled line pattern LP2 is a pattern in which ruled lines of different colors that are substantially directed in a direction orthogonal to the nozzle row direction are arranged in a comb-like shape substantially along the nozzle row direction. Each ruled line constituting the ruled line pattern LP2 is a nozzle belonging to a different nozzle row in the print head 22b, and is printed by nozzles corresponding to different color inks.

  Specifically, the ruled line pattern LP2 shown in FIG. 10 has K ruled lines printed by the nozzles in the a column and M ink ruled lines (M ruled lines) printed by the nozzles in the h column alternately arranged in parallel. Yes. In other words, the positions of the nozzles in the a row and the nozzles in the h row are shifted from each other by P in the nozzle row direction, so the K ruled lines printed by the nozzles in the a row and the M ruled lines printed by the nozzles in the h row are basically Thus, the relationship is arranged between each other. Of course, the ruled line pattern LP2 may be formed by K ruled lines and M ruled lines using nozzles in b rows and nozzles in g rows. Thus, the test pattern TP2 printed with a combination of ruled lines of different colors (not limited to a combination of K ruled lines and M ruled lines) evaluates the positional relationship between the ruled lines of different colors. However, when printing the test pattern TP2, the ruled line does not necessarily have a comb-teeth shape.

  FIG. 11 shows a test pattern TP2 printed on the paper S in the second embodiment, which is an example different from FIG. The test pattern TP2 in FIG. 11 includes a plurality of ruled line patterns LP3, and each ruled line pattern LP3 is configured by ruled lines of different colors that are substantially directed in a direction orthogonal to the nozzle row direction. Specifically, in the ruled line pattern LP3, the K ruled lines printed by the nozzles in the b column and the M ruled lines printed by the nozzles in the h column are substantially continuous. The positions of the nozzles in the b row and the nozzles in the h row are the same position in the nozzle row direction. For this reason, the K ruled lines printed by the b-row nozzles and the M ruled lines printed by the g-row nozzles are basically continuous in a straight line. Of course, the ruled line pattern LP3 may be formed by K ruled lines and M ruled lines using the nozzles in the a row and the nozzles in the g row.

  When the test pattern TP2 as described above is printed, in S110, the system 60 performs an evaluation based on a plurality of test patterns TP2, and calculates an evaluation value. That is, if the pattern is comb-like as shown in FIG. 10, about a predetermined number of ruled lines (M ruled lines) printed by one nozzle row (for example, h row) among the nozzle rows used for printing, Is it at the center position that should be originally between the ruled lines (K ruled lines) printed by the other nozzle row (a row), is it located above the center location, or is located below the center location? , Make a rating. On the other hand, if the pattern is linear as shown in FIG. 11, the predetermined number of ruled lines (M ruled lines) printed by one nozzle line (for example, h line) among the nozzle lines used for printing, Is continuous with the ruled line (K ruled line) printed with the nozzle row (b row) (0 point), the linearity is broken and shifted upward (+1 point), or the linearity is broken It is evaluated whether it is shifted downward (-1 point). It is preferable to print the test pattern TP2 with a combination of ruled lines of different colors in this way because it is easy to evaluate the presence or absence and degree of positional deviation between ruled lines.

Example 3
FIG. 12 shows the ink ejection unit 22 to be adjusted in the third embodiment. The ink discharge unit 22 used in the third embodiment is one print head unit 22c. In the present embodiment, the print head unit forms one line head, and the length of the print head unit in the longitudinal direction corresponds to the paper width W of the paper S. The configuration of each print head of the print head unit 22c is the same as that of the print head 22a (see FIG. 5). In FIG. 12, only four print heads 22a1, 22a2, 22a3, 22a4 are shown in order from one end side of the print head unit 22c, but the number of print heads constituting the print head unit 22c is not particularly limited. In the print head unit 22c, the odd-numbered print heads 22a1, 22a3,... Form one row, and the even-numbered print heads 22a2, 22a4,. The odd-numbered print head columns and the even-numbered print head columns are shifted from each other in the column direction, and the print heads in one column are arranged between the print heads in the other column.

  Each print head of the print head unit 22c partially overlaps the upper and lower print heads in the nozzle row direction. In the present embodiment, a range in which the print heads overlap in the print head unit is referred to as an overlap range OR. In the overlap range OR of the print head unit 22c, the nozzle position of one print head and the nozzle position of the other print head coincide with each other in the nozzle row direction. Specifically, in the overlap range OR of the print head 22a1 and the print head 22a2, the nozzle position of the a row of the print head 22a1 and the nozzle position of the a row of the print head 22a2 coincide in the nozzle direction. For the b to h rows of both print heads 22a1 and 22a2, the nozzle positions of the same nozzle rows are the same in the nozzle row direction. In the present embodiment, a print head unit in which the nozzle positions of the print heads that overlap in the overlap range OR coincide in the nozzle direction is referred to as a print head unit in which the print heads are arranged in ideal alignment.

  Even when the ink discharge unit 22 is a print head unit (print head unit 22c or a print head unit 22d described later), the ink discharge unit 22 includes an angle adjustment plate 411, an angle adjustment dial 412, a translation plate 413, and a translation movement. A dial 414 is provided. The print head unit is connected to the angle adjustment plate 411. When the angle adjustment plate 411 rotates, the entire print head unit rotates in accordance with the rotation. The relationship between the angle adjustment plate 411 and the angle adjustment dial 412 is as already described. Further, the print head unit is connected to the translation plate 413. When the translation plate 413 moves, the entire print head unit moves accordingly. The relationship between the translation plate 413 and the translation dial 414 is as already described. In S100, the system 60 prints the test pattern TP3 on the plurality of sheets S by the printer 20.

  FIG. 13 simply illustrates the relationship between the test pattern TP3 printed on the paper S and the print head unit 22c in the third embodiment. The test pattern TP3 includes a plurality of comb-like ruled line patterns LP1 (see FIGS. 6 and 7). In the test pattern TP3, each ruled line pattern LP1 is printed for each of the areas 1, 2, 3, 4,. For example, each ruled line pattern LP1 in the region 1 is composed of K ruled lines printed by the nozzles in the a and h columns of the print head 22a1. Similarly, each ruled line pattern LP1 in the areas 2, 3, 4... Is composed of K ruled lines printed by the a-row and h-row nozzles of the print heads 22a2, 22a3, 22a4. Each ruled line pattern LP1 shown in FIG. 13 is printed by nozzles that do not belong to the overlap range OR in the corresponding print head.

  FIG. 14 shows a test pattern TP3 printed on the paper S in the third embodiment, which is an example different from FIG. Also in FIG. 14, the test pattern TP3 includes a plurality of ruled line patterns LP1, and each ruled line pattern LP1 is printed for each of the areas 1-2, 2-3, and 3-4 of the paper S. The test pattern TP3 in FIG. 14 is printed by the nozzle row of one print head and the nozzle row of the other print head that overlap in the overlap range OR. As an example, each ruled line pattern LP1 in the area 1-2 includes the K ruled lines printed by the nozzles in the a column of the print head 22a1 and the h columns of the print head 22a2 in the overlap range OR of the print head 22a1 and the print head 22a2. And K ruled lines printed by the nozzles. Similarly, each ruled line pattern LP1 in the area 2-3 is composed of K ruled lines printed by the nozzles in the h column of the print head 22a2 and the a column of the print head 22a3 in the overlap range OR of the print head 22a2 and the print head 22a3. Each of the ruled line patterns LP1 in the region 3-4 is configured by K ruled lines printed by the nozzles of the a column of the print head 22a3 and the h column of the print head 22a4 in the overlap range OR of the print head 22a3 and the print head 22a4. ing.

  FIG. 15 shows a test pattern TP3 printed on the paper S in the third embodiment, which is an example different from those in FIGS. The test pattern TP3 in FIG. 15 includes a plurality of ruled line patterns LP4. Each ruled line pattern LP4 is configured to be substantially directed in a direction orthogonal to the nozzle row direction by two substantially same ruled lines printed by the same color nozzles having the same position in the nozzle row direction. Each ruled line pattern LP4 is printed for each of the areas 1-2, 2-3, and 3-4 of the paper S, and the nozzle array of one print head and the nozzle array of the other print head that overlap in the overlap range OR. Printed by. As an example, each ruled line pattern LP4 in the area 1-2 is composed of K ruled lines printed by the nozzles in the a column of the print head 22a1 and the print head 22a2 in the overlap range OR of the print head 22a1 and the print head 22a2. Yes. Similarly, each ruled line pattern LP4 in the area 2-3 is composed of K ruled lines printed by the nozzles in the a row of the print head 22a2 and the print head 22a3 in the overlap range OR of the print head 22a2 and the print head 22a3. Each ruled line pattern LP4 of 3-4 is composed of K ruled lines printed by the print head 22a3 and the nozzles in the a column of the print head 22a4 in the overlap range OR of the print head 22a3 and the print head 22a4. Of course, the color of the ruled lines constituting the test pattern TP3 is not limited to K.

  When the test pattern TP3 as described above is printed, in S110, the system 60 performs an evaluation based on a plurality of test patterns TP3 and calculates an evaluation value. The evaluation method for the test pattern TP3 shown in FIG. 13 or FIG. 14 is the same as the evaluation method for the test pattern TP1 (Example 1). If the test pattern TP3 is a linear pattern as shown in FIG. 15, in each ruled line pattern LP4 constituted by two ruled lines, one of the left and right ruled lines (for example, the right) is checked with respect to the other. It is continuous with the left (left) ruled line (0 point), the linearity is broken and shifted upward (+1 point), or the linearity is broken and shifted downward (-1 point) ) Or rating.

  In S140, the system 60 adjusts the angle of the ink discharge unit 22 (the print head unit 22c in the third embodiment) according to the rotation amount specified in the latest S130. The adjustment is performed by operating the angle adjustment plate 411 and the angle adjustment dial 412 connected to the print head unit 22c. Thus, according to the third embodiment, it is possible to adjust the inclination of the entire print head unit 22c based on the test pattern TP3.

Example 4
In S100, the system 60 prints the test pattern TP4 on a plurality of sheets S. FIG. 16 simply illustrates the relationship between the ink ejection unit 22 and the test pattern TP4 in the fourth embodiment. In the fourth embodiment, the ink discharge unit 22 is a print head unit 22d. The only difference between the print head unit 22d and the print head unit 22c (see FIG. 12) is the arrangement of the nozzle rows in each print head. The configuration of each print head 22b1, 22b2, 22b3, 22b4 of the print head unit 22d is the same as that of the print head 22b (see FIG. 9). Therefore, the print head unit 22d also has the print heads arranged in ideal alignment.

  The difference between the third embodiment and the fourth embodiment is that the test pattern TP3 printed in the former is printed in the same color while the test pattern TP4 printed in the latter is printed in a different color. The test pattern TP4 in FIG. 16 includes a plurality of comb-like ruled line patterns LP2 (see FIG. 10). As an example, each ruled line pattern LP2 in the region 1 has columns a and b in the print head 22b1. It is formed by K ruled lines and M ruled lines printed by the nozzles in (g row). Similarly, each ruled line pattern LP2 in the areas 2, 3, 4... Is printed with K ruled lines and M printed by the nozzles in the a column (b column) and the h column (g column) of each print head 22b2, 22b3, 22b4. It is formed with ruled lines. Each ruled line pattern LP2 shown in FIG. 16 is printed by nozzles that do not belong to the overlap range OR in the corresponding print head.

  FIG. 17 shows a test pattern TP4 printed on the paper S in the fourth embodiment, which is an example different from FIG. The test pattern TP4 in FIG. 17 includes a plurality of ruled line patterns LP2 printed for each of the areas 1-2, 2-3, and 3-4, and these are printed by nozzles in the overlap range OR. That is, the ruled line patterns LP2 in the area 1-2 are the nozzles in the a row (b row) of the print head 22b1 and the h row (g row) of the print head 22b2 in the overlap range OR of the print head 22b1 and the print head 22b2. Is formed with K ruled lines and M ruled lines printed by Similarly, each ruled line pattern LP2 in the region 2-3 and each ruled line pattern LP2 in the region 3-4 are printed by the nozzles of the respective print heads in the corresponding overlap range OR.

  FIG. 18 shows a test pattern TP4 to be printed on the paper S in the fourth embodiment, which is an example different from FIGS. The test pattern TP4 in FIG. 18 includes a plurality of ruled line patterns LP3 (see FIG. 11) printed for each of the areas 1-2, 2-3, and 3-4, and these are printed by nozzles in the overlap range OR. Yes. That is, for each ruled line pattern LP3 in the area 1-2, the a row (b row) of the print head 22b1 and the g row (h row) of the print head 22b2 in the overlap range OR of the print head 22b1 and the print head 22b2. Are formed by K ruled lines and M ruled lines printed by the nozzles. Similarly, each ruled line pattern LP3 in the area 2-3 and each ruled line pattern LP3 in the area 3-4 are printed by the nozzles of the respective print heads in the corresponding overlap range OR.

  Further, in the fourth embodiment, the first pattern is not limited to the test pattern TP4 shown in FIGS. 16 to 18, and the area 1 is defined by the nozzles outside the overlap range OR of the print heads 22b1, 22b2, 22b3, 22b4. , 2, 3, 4..., Another test pattern TP4 may be output by printing the ruled line pattern LP3. When the test pattern TP4 as described above is printed, the evaluation based on the plurality of test patterns TP4 in S110 is the same as the evaluation method shown in the second embodiment. It is preferable to print the test pattern TP4 with a combination of ruled lines of different colors in this way because it is easy to evaluate the presence and degree of positional deviation between the ruled lines, and the inclination of the entire print head unit 22d can be adjusted. .

Example 5
FIG. 19 shows a print head unit group 22 e as the ink discharge unit 22. The print head unit group 22e is formed by arranging a plurality (two) of print head units 22c in a direction perpendicular to the nozzle row direction (or arranging two print head units 22d in a direction perpendicular to the nozzle row direction. ) Is formed. In the print head unit group 22e, a print head unit positioned on the upstream side in the transport direction of the paper S is referred to as a preceding unit, and a print head unit positioned on the downstream side in the transport direction is referred to as a subsequent unit. In the print head unit group 22e, the positional relationship between the preceding unit and the succeeding unit in the nozzle row direction is shifted by P / 2. That is, the preceding unit and the succeeding unit have a relationship in which the nozzle positions of the same nozzle number of the same nozzle row of the same print head in both units are shifted by P / 2 in the nozzle row direction. By shifting the positional relationship between the preceding unit and the succeeding unit in the nozzle row direction, the nozzles are arranged at P / 2 in the nozzle row direction when viewed in the entire print head unit group 22e, so that high-definition printing can be performed. It becomes possible.

  In the fifth embodiment, in the situation where the inclination adjustment processing (third or fourth embodiment) according to FIG. 4 has already been completed for the preceding unit, as shown in FIG. The tilt adjustment processing (Embodiment 3 or Embodiment 4) is performed. In other words, the test pattern is printed for each print head unit constituting the print head unit group 22e, and the tilt adjustment is performed based on the print result. However, the tilt adjustment of the succeeding unit may be performed based on the angle of the preceding unit for which the tilt adjustment has already been completed. In this case, the system 60 prints ruled lines on the paper S by the nozzle row having the preceding unit and the nozzle row having the succeeding unit. Then, it determines how much the angle of the succeeding unit should be corrected in accordance with the inclination of the ruled line printed by the succeeding unit with respect to the ruled line printed by the preceding unit, and follows the amount of correction (rotation amount) of the determined angle. Adjust the angle of the row unit.

  In the above description, the print head unit group 22e is taken as an example to describe the fifth embodiment. However, for example, the ink ejection unit 22 may include a plurality of (two) “print heads” in a direction orthogonal to the nozzle row direction. It may be a “print head group” configured by arranging. The print head group is not formed by arranging a plurality of print heads in the nozzle row direction like the print head unit. Then, it is possible to individually perform the inclination adjustment processing (Example 1 or Example 2) according to FIG. 4 for each print head (preceding print head, subsequent print head) constituting the print head group, It is also possible to adjust the inclination of the succeeding print head based on the angle of the preceding print head for which the inclination adjustment has already been completed.

Example 6
FIG. 20 shows a state in which the inclination is adjusted in units of print heads 22a1, 22a2, 22a3, 22a4 (or print heads 22b1, 22b2, 22b3, 22b4) constituting the print head unit 22c (or print head unit 22d). Yes. That is, the tilt adjustment processing (Example 1 or Example 2) according to FIG. 4 can be performed on a desired print head in the print head unit. However, in Example 6, since one print head in the print head unit is an adjustment target, the test pattern is not printed over the entire paper width W of the paper S, and the print head (for example, the adjustment target at that time, for example, The test pattern is printed in the transport direction of the paper S only in the area corresponding to the print head 22a2).

Example 7
The print head unit (print head unit 22c or print head unit 22d) is not limited to one in which the print heads are arranged in ideal alignment. As shown in FIG. The nozzle position of the print head and the nozzle position of the other print head may be shifted in the nozzle row direction. In the example of FIG. 21, the nozzle positions of the same nozzle rows are shifted by P / 2 in the nozzle row direction for each of the a to h rows of both print heads belonging to the overlap range OR. In this way, in a print head unit in which the nozzle positions of the same nozzle row in both print heads overlapping in the overlap range OR are shifted by P / n in the nozzle row direction, the print head is arranged with 1 / n alignment. Called the head unit. In FIG. 21, the components such as the angle adjustment plate 411 are omitted as appropriate.

  You may perform the inclination adjustment process of Examples 3-6 mentioned above using the print head unit by which the print head was arrange | positioned by P / n alignment. However, when printing a test pattern using the nozzles of both print heads belonging to the overlap range OR, the nozzles of one print head and the other print head of both print heads overlapping in the overlap range OR , Nozzles that are alternately and equally spaced in the nozzle row direction are selected (for example, in FIG. 21 (print head unit 22d in which the print head is arranged in P / 2 alignment), the print head 22b1 indicated by a black circle) The nozzles of the a-column- # 177, b-column- # 179, a-column- # 180 and the nozzles of the print head 22b2, the g-column- # 2, the h-column- # 4, etc. are selected) The comb-like pattern is printed using the selected nozzle.

3. Vertical Alignment Adjustment Process FIG. 22 is a flowchart showing the vertical alignment adjustment process of the ink ejection unit 22 executed by the system 60. Also in the vertical alignment adjustment process, a plurality of ruled lines represented by the ink ejected from each nozzle are ejected from each nozzle belonging to a different nozzle array included in the ink ejection unit 22 to be adjusted. A ruled line pattern composed of a combination of a plurality of ruled lines substantially facing a direction orthogonal to the direction is printed on the paper S as evenly as possible. Then, based on the position of the ruled line in each ruled line pattern, the position (position in the vertical direction, also referred to as the vertical position) of the ink ejection unit 22 as the adjustment target is adjusted. At the start of the vertical alignment adjustment process, the ink ejection unit 22 is disposed in a somewhat ideal vertical position (initial setting position) in the printer 20.

  Examples 8 to 13 of the vertical alignment adjustment process will be described below based on the flowchart of FIG. The vertical alignment adjustment process will be described with respect to differences from the matters already described in the inclination adjustment process.

Example 8
In S200, the system 60 prints the test pattern TP5 on the plurality of sheets S by the printer 20.
FIG. 23 simply illustrates the relationship between the ink ejection unit 22 and the test pattern TP5 printed on the paper S in the eighth embodiment. In the eighth embodiment, the ink ejection unit 22 is a print head unit group 22e composed of two print head units 22d. In the eighth embodiment, the vertical position of the succeeding unit is adjusted based on the vertical position of the preceding unit. The test pattern TP5 is composed of a plurality of comb-like ruled line patterns LP1 (see FIGS. 6 and 7, etc.). In the test pattern TP5, each ruled line pattern LP1 is printed for each of the areas 1, 2, 3, 4... Obtained by dividing the paper S in the vertical direction.

  The ruled line pattern LP1 of each area is printed by the print head of the preceding unit and the print head of the subsequent unit corresponding to the area. As an example, each ruled line pattern LP1 in the region 1 is formed by K ruled lines printed by the a and b columns of the print head 22b1 of the preceding unit and the a and b columns of the print head 22b1 of the succeeding unit. As described above, the preceding unit and the succeeding unit are shifted by P / 2 in the nozzle row direction. Therefore, by ejecting ink from the nozzle rows of the same color of the preceding unit and the succeeding unit, a comb-like pattern with the ruled lines of the same color is printed. Similarly, the ruled line patterns LP1 in the areas 2, 3, 4... Are printed in the print heads 22b2 in the preceding unit and the succeeding unit, the print heads 22b3 in the preceding unit and the succeeding unit, and the printing in the preceding unit and the succeeding unit. It is formed by K ruled lines printed by the heads 22b4.

When the test pattern TP5 is printed, in S210, the system 60 performs evaluation based on a plurality of test patterns TP5 and calculates an evaluation value. The evaluation value calculation method is the same as S110 of the first embodiment. The process of S220 is the same as S120.
In S230, the computer 10 specifies the amount of movement of the ink ejection unit 22 corresponding to the evaluation value calculated in the latest S210. The computer 10 has, as information, a table or a function that defines a correspondence relationship between the evaluation value and the movement amount in advance, and identifies a movement amount that uniquely corresponds to the evaluation value with reference to the correspondence relationship. Here, for example, when the evaluation value is a positive value, the amount of movement in the − direction (downward) according to the value is used, and when the evaluation value is a negative value, the + direction according to the value ( A correspondence relationship such as a movement amount to the upper side) is defined.

  In S240, the system 60 adjusts the vertical position of the ink ejection unit 22 (in the eighth embodiment, the trailing unit in the print head unit group 22e) according to the movement amount specified in the latest S230. The system 60 can also use the jig 50 for the adjustment. That is, the computer 10 sends a command for moving the subsequent unit according to the specified movement amount to the jig 50, and the jig 50 receiving the command translates the subsequent unit as the adjustment target according to the movement amount. The moving plate 413 is moved in the vertical direction. At this time, the jig 50 may be moved by operating the translation dial 414 according to the amount of movement, or the translation plate 413 may be moved directly.

  After S240, the process returns to S200 again, and the processing from printing of a plurality of test patterns TP5 is repeated. That is, the test pattern printing and the adjustment based on the printing result are repeated until the evaluation value converges within the high evaluation range. As a result, even if a conveyance error such as meandering occurs on the paper S, the positional relationship between the preceding unit and the succeeding unit constituting the ink ejection unit 22 in the vertical direction is determined based on the influence of the meandering. It is possible to adjust the positional relationship so that the shift is hardly visible on the entire sheet. Note that some or all of the processes in S210 to S240 in FIG. 22, that is, some or all of the processes such as scoring for each ruled line, calculation of evaluation values, identification of the movement amount, and vertical position adjustment of the ink ejection unit 22 are performed. May be performed artificially.

  As described above, the characteristic of the meandering of the paper S is considered to occur repeatedly at a certain period due to the rotation characteristics of the rollers, motors, etc. of the paper transport unit 21. Therefore, also in the vertical alignment adjustment process, a plurality of test patterns are printed as described above, and the evaluation value is obtained based on the printing result at each position of the plurality of test patterns, so that the ink discharge unit that is the adjustment target at that time The vertical position for 22 is adjusted to an average reasonable position for all meandering conditions.

Example 9
In the ninth embodiment and the other tenth to thirteenth embodiments, parts different from the eighth embodiment will be described. The difference between the eighth embodiment and the ninth embodiment is that the test pattern TP5 printed in the former is printed in the same color, while the test pattern TP6 printed in the latter is printed in a different color.
That is, the test pattern TP6 in FIG. 24 includes a plurality of comb-like ruled line patterns LP2 (see FIG. 10 and the like), and each ruled line pattern LP2 is an area 1, 2, 3, 4. Printed every time.

  The ruled line pattern LP2 in each area is printed by the print head of the preceding unit and the print head of the succeeding unit corresponding to the area. As an example, each ruled line pattern LP2 in the region 1 is formed by K ruled lines printed by the a and b columns of the print head 22b1 of the preceding unit and M ruled lines printed by the g and h columns of the print head 22b1 of the succeeding unit. Has been. Since the preceding unit and the succeeding unit are shifted by P / 2 in the nozzle row direction, by ejecting ink from nozzle rows of different colors of the preceding unit and the succeeding unit, comb-like shapes with different color ruled lines are formed. The pattern is printed. Similarly, each ruled line pattern LP2 in the areas 2, 3, 4... Has different color nozzle rows in the print heads 22b2 of the preceding unit and the succeeding unit, and different colors in the print heads 22b3 of the preceding unit and the succeeding unit. It is formed with ruled lines printed by nozzle rows of different colors in the print heads 22b4 of the nozzle row, the preceding unit, and the succeeding unit.

  When the test pattern TP6 as described above is printed, the evaluation based on the plurality of test patterns TP6 in S210 is the same as the evaluation method shown in the second embodiment. It is preferable to print the test pattern TP6 with a combination of ruled lines of different colors in this way, because it is easy to evaluate the presence / absence and degree of positional deviation between ruled lines. The print head unit group 22e to which the eighth and ninth embodiments are applied may have a configuration in which the print heads are arranged with ideal alignment or a configuration in which the print heads are arranged with 1 / n alignment. In the above description, the examples 8 and 9 have been described by taking the relationship between the preceding unit and the succeeding unit of the print head unit group 22e as an example. However, the ink discharge unit 22 that is the target of the examples 8 and 9 The print head group described above may be used. That is, according to the flowchart of FIG. 22, the vertical position of the subsequent print head may be adjusted based on the position of the preceding print head constituting the print head group.

Example 10
In S200, the system 60 prints the test pattern TP7 on the plurality of sheets S by the printer 20.
FIG. 25 simply illustrates the relationship between the ink ejection unit 22 and the test pattern TP7 printed on the paper S in the tenth embodiment. In the tenth embodiment, the ink ejection unit 22 is a print head unit 22d in which a plurality of print heads 22b1, 22b2, 22b3, 22b4. In the tenth embodiment, the vertical alignment is adjusted for each print head of the print head unit 22d. That is, one print head is selected as an adjustment target, and the vertical position of the print head that is the adjustment target is adjusted with reference to the vertical position of another print head that shares the overlap range OR with the adjustment target print head. To do.

  FIG. 25 illustrates a case where the print head 22b2 is selected as an adjustment target. In this case, in the test pattern TP7, the plurality of comb-like ruled line patterns LP1 printed by the nozzles in the overlapping range OR where the print head 22b2 and the print head 22b1 overlap, and the print head 22b2 and the print head 22b3 overlap. It consists of a plurality of comb-like ruled line patterns LP1 printed by nozzles in the wrapping range OR. Each ruled line pattern LP1 corresponding to the overlap range OR of the print head 22b1 and the print head 22b2 is the K ruled line printed by the nozzles in the a row (b row) of the print head 22b1 and the b row (a row) of the print head 22b2. Each ruled line pattern LP1 corresponding to the overlap range OR of the print head 22b2 and the print head 22b3 is composed of K ruled lines printed by the nozzles of the print heads 22b3 and K printed by the nozzles of the a row (b row) of the print head 22b3. It is composed of ruled lines and K ruled lines printed by nozzles in the b row (a row) of the print head 22b2.

  Of course, similarly to a part of the test pattern TP3 shown in FIG. 15, each ruled line pattern LP4 corresponding to the overlap range OR of the print head 22b1 and the print head 22b2 (with the nozzles in a row of the print head 22b1 and the print head 22b2). The ruled line pattern composed of the printed K ruled lines) and each ruled line pattern LP4 corresponding to the overlap range OR of the print head 22b2 and the print head 22b3 (printed by the nozzles in the a column of the print head 22b2 and the print head 22b3) K ruled line pattern) may be printed as the test pattern TP7 when the print head 22b2 is the adjustment target.

  In S240, the system 60 adjusts the vertical position of the ink ejection unit 22 (in the tenth embodiment, the print head 22b2 in the print head unit 22d) according to the movement amount specified in S230. The adjustment is performed by operating the translation plate 413 and the translation dial 414 connected to the print head to be adjusted. As described above, according to the tenth embodiment, it is possible to adjust the vertical alignment of the single print head in the print head unit based on the test pattern TP7.

Example 11
In S200, the system 60 prints the test pattern TP8 on the plurality of sheets S by the printer 20.
FIG. 26 simply illustrates the relationship between the ink ejection unit 22 and the test pattern TP8 printed on the paper S in the eleventh embodiment. In the eleventh embodiment, the ink ejection unit 22 is a print head unit 22d in which a plurality of print heads 22b1, 22b2, 22b3, 22d4,. The difference between the tenth embodiment and the eleventh embodiment is that the test pattern TP7 printed in the former is printed in the same color while the test pattern TP8 printed in the latter is printed in a different color.

  FIG. 26 illustrates a case where the print head 22b2 is selected as an adjustment target. In this case, in the test pattern TP8, the plurality of comb-like ruled line patterns LP2 printed by the nozzles in the overlapping range OR where the print head 22b2 and the print head 22b1 overlap, and the print head 22b2 and the print head 22b3 overlap. It consists of a plurality of comb-like ruled line patterns LP2 printed by nozzles in the wrapping range OR. That is, in the test pattern TP8, the ruled line patterns LP2 corresponding to the overlap range OR of the print head 22b1 and the print head 22b2 are the nozzles in the a row (b row) of the print head 22b1 and the h row (g row) of the print head 22b2. Is formed with K ruled lines and M ruled lines printed by Further, each ruled line pattern LP2 corresponding to the overlap range OR of the print head 22a2 and the print head 22a3 was printed by the nozzles of the a row (b row) of the print head 22a3 and the h row (g row) of the print head 22b2. It is formed by K ruled lines and M ruled lines.

  Of course, like the part of the test pattern TP4 shown in FIG. 18, the ruled line patterns LP3 corresponding to the overlap range OR of the print head 22b1 and the print head 22b2 (the a row (b row) of the print head 22b1 and the print head). A ruled line pattern composed of K ruled lines and M ruled lines printed in the g column (h column) of 22b2, and each ruled line pattern LP3 corresponding to the overlap range OR of the print head 22b2 and the print head 22b3 (a of the print head 22b3) And a test pattern TP8 when the print head 22b2 is an adjustment target, and the test pattern TP8 when the print head 22b2 is an adjustment target. May be.

  When the test pattern TP8 as described above is printed, the evaluation based on the plurality of test patterns TP8 in S210 is the same as the evaluation method shown in the second embodiment. It is preferable to print the test pattern TP8 with a combination of ruled lines of different colors in this way because it is easy to evaluate the presence or absence and degree of positional deviation between the ruled lines, and the vertical alignment adjustment of the single print head in the print head unit is preferable. Can be done.

Example 12
The tenth embodiment can also be applied to the case where the ink discharge unit 22 is a print head unit 22d (see FIG. 21) in which the print heads are arranged with 1 / n alignment. In this case, when the test pattern TP7 composed of ruled lines of the same color is printed by the nozzles belonging to the overlap range OR, the nozzles of one print head of both print heads overlapping in the overlap range OR are printed as in the seventh embodiment. And the nozzles of the other print head which are alternately and equally spaced in the nozzle row direction (in the example of FIG. 21, the a row of the print head 22b1-# 177, b row- # 179, the nozzles in row a- # 180 and the nozzles in rows a- # 2, b- # 4 of print head 22b2 are selected), and the comb-like pattern is formed using the selected nozzles. Print.

Example 13
Embodiment 11 can also be applied to the case where the ink ejection unit 22 is a print head unit 22d (see FIG. 21) in which the print heads are arranged with 1 / n alignment. In this case, when printing the test pattern TP8 composed of ruled lines of different colors with the nozzles belonging to the overlap range OR, as in the seventh embodiment, one print head of both print heads overlapping in the overlap range OR is printed. The nozzles and the nozzles of the other print head, which are alternately and equally spaced in the nozzle row direction, are selected (in the example of FIG. 21, the a row- # 177, b row of the print head 22b1 -Select each nozzle of # 179, a row-# 180 and each nozzle of g row-# 2, h row-# 4 of the print head 22b2, and use the selected nozzles to form the comb-like pattern. To print.

  In addition, when the ink discharge unit 22 is a print head unit group 22e composed of a preceding head and a following head, and the vertical alignment adjustment process is performed on a single print head in the print head unit group 22e, the tenth embodiment described above. 13 can be applied.

4). Print Timing Adjustment Process FIG. 27 is a flowchart showing the print timing adjustment process of the ink ejection unit 22 executed by the system 60. In the printing timing adjustment process, a ruled line pattern composed of a combination of a plurality of ruled lines substantially directed in the nozzle row direction is ejected from a predetermined nozzle row provided in the ink discharge unit 22 to be adjusted in the printer 20, and the paper S Printing is performed at a plurality of positions spaced apart in the direction perpendicular to the nozzle row direction (printing a test pattern in which ruled line patterns are evenly arranged). Then, based on the position of the ruled line in each ruled line pattern, the ink ejection timing from each nozzle row of the ink ejection unit 22 to be adjusted is adjusted.
Examples 14 to 21 of the print timing adjustment process will be described below based on the flowchart of FIG.

Example 14
In S300, the system 60 prints the test pattern TP9 on a plurality of sheets S.
FIG. 28 shows the relationship between the ink ejection unit 22 to be adjusted in Example 14 and the test pattern TP9 printed on the paper S. In the fourteenth embodiment, it is assumed that the ink ejection unit 22 is a print head (print head 22a or print head 22b; the same applies hereinafter), and the printer 20 is a serial type. The test pattern TP9 is composed of the ruled line pattern LP5 of the same color printed on the paper S at a predetermined interval in the main scanning direction. One ruled line pattern LP5 is a substantially linear pattern in which a plurality of ruled lines of the same color substantially in the nozzle row direction are substantially continuous. In FIG. 28, one ruled line pattern LP5 is formed by ruled lines that are printed in regions 1, 2, 3, 4,.

  That is, a plurality of ruled lines are printed at intervals in the main scanning direction by the movement of the print head in the main scanning direction (movement accompanied by ink ejection), and such printing is performed every time a predetermined amount of paper S is conveyed. As a result, ruled lines are sequentially printed in the respective areas 1, 2, 3, 4. Specifically, the print head prints ruled lines by ejecting ink while moving in the main scanning forward direction (the direction from left to right) with respect to the odd-numbered regions 1, 3,. A ruled line is printed by ejecting ink while moving in the main scanning backward direction (direction from right to left) with respect to the areas 2, 4. In the fourteenth embodiment, each ruled line constituting the ruled line pattern LP5 is printed by nozzle rows corresponding to the same color in the print head. In FIG. 28, as an example, each ruled line constituting the ruled line pattern LP5 is a K ruled line.

  The ruled line pattern LP5 (the same applies to the ruled line patterns printed in Examples 15 to 20) is printed based on image data expressing a straight line. Therefore, the ruled line pattern LP5 is ideally expressed as a straight line on the paper S. However, in the printer 20, the relative speed between the ink ejection unit 22 and the paper S when ejecting ink (in the serial type printer 20, the speed of the ink ejection unit 22 that moves on the stationary paper S, and the line In the head type printer 20, the speed of the sheet S conveyed under the stationary ink discharge unit 22 is not strictly constant. For this reason, the relative speed between the ink ejection unit 22 and the paper S during printing varies for each position of the paper S. Further, in the case of the serial type printer 20, such a variation is different between the movement in the main scanning forward direction and the movement in the main scanning backward direction. Accordingly, the ruled line pattern LP5 on the paper S is not necessarily an exact straight line in the nozzle row direction, and each ruled line may be shifted to the left and right as shown in FIG. Therefore, the ruled line pattern LP5 on the paper S is expressed as “a substantially linear pattern in which ruled lines are substantially continuous”.

  The procedure for printing the test pattern on the paper S in S300 is as described in S100 above. In S310, the system 60 performs evaluation based on a plurality of test patterns TP9 printed in the latest S300, and calculates an evaluation value. In S310, similarly to S110 and S210, the system 60 reads the test patterns one by one by the scanner 30, and transfers the image data of each test pattern obtained by the reading to the computer 10. The computer 10 analyzes the transferred image data to perform score evaluation on the test pattern and calculate the evaluation value. Specifically, one of the regions 1, 2, 3, 4... Is used as a reference region, and the position of the ruled line in another region (target region) with respect to the ruled line printed in the reference region is evaluated.

  As an example, the computer 10 uses the region 1 as a reference region, and evaluates the position of the ruled line in the target region (region 2) adjacent to the region 1. That is, the computer 10 analyzes the image data of the plurality of test patterns TP9, and each ruled line printed on the area 2 of each sheet S is continuous with the ruled line in the upper area 1 that should be continuous in a straight line. In the main scanning direction or the ruled line of the region 1 that should originally be continuous (in the center position), or the region 1 that should originally be continuous in a straight line It is evaluated whether it is located on the right side of the ruled line or on the left side of the ruled line of the region 1 that should be continuous in a straight line. For example, the computer 10 gives “0 point” as a score to a ruled line evaluated as being in the center position, and gives “+1 point” to a ruled line evaluated as being located on the left side of the center position. Given, “−1 point” is given to the ruled line evaluated to be located on the right side of the center position. In this way, all the points given to each ruled line in each area 2 are totaled, and the total score is set as an overall evaluation value for the area 2 of the plurality of test patterns TP9.

  In S320, the computer 10 determines whether or not the evaluation value calculated in the latest S310 is within a predetermined high evaluation range (0 points ± predetermined points), and the evaluation value is within the high evaluation range. Ends the evaluation and adjustment for the target region (region 2) at that time. In other words, if the evaluation value is 0 point or a value close to a predetermined value close to 0 point, the print timing in the area 1 and the print timing in the area 2 over a plurality of sheets S are slightly caused by the relative speed variation. This is because even if there is a deviation, it can be said that printing is executed in each of the areas 1 and 2 at appropriate printing timings that make the influence of the deviation least felt when viewed on the plurality of sheets S as a whole. On the other hand, if the evaluation value is out of the high evaluation range, the computer 10 determines that adjustment of the print timing for the target area (area 2) is necessary, and proceeds to S330.

  In S330, the computer 10 specifies the adjustment amount of the print timing of the ink discharge unit 22 (print timing when the target region is printed by the ink discharge unit 22) corresponding to the evaluation value calculated in the latest S310. The computer 10 previously has information such as a table or a function that defines the correspondence between the evaluation value and the adjustment amount, and specifies the adjustment amount that uniquely corresponds to the evaluation value with reference to the correspondence. In addition, when printing is performed during movement in each of the main scanning forward direction and the main scanning backward direction as described above, it is considered whether the target area is printed in the main scanning forward direction or the main scanning backward direction. Identify the adjustment amount. For example, if the target area is an area to be printed by movement in the main scanning forward direction (area 3 or the like), if the evaluation value is a positive value, an adjustment amount that delays the printing timing according to that value. If the evaluation value is a negative value, an adjustment amount for increasing the printing timing is set according to the negative value. On the other hand, if the target area is an area printed by movement in the main scanning backward direction (area 2 or the like), if the evaluation value is a positive value, the adjustment amount is set to advance the printing timing according to the value. If the evaluation value is a negative value, an adjustment amount for delaying the print timing is set according to the negative value.

  In S340, the computer 10 instructs the printer 20 to adjust the timing of ink ejection by the ink ejection unit 22 with respect to the target area (area 2) according to the adjustment amount specified in the latest S330, and the printer 20 In response to the instruction, ink ejection timing adjustment is executed. In the printer 20, the drive signal generation circuit 25 generates a drive signal and supplies it to each nozzle of the ink ejection unit 22. The drive signal is a signal for generating a drive pulse at a cycle set on the assumption that the relative speed between the ink ejection unit 22 and the paper S is a certain value, and the drive pulse of the predetermined cycle is a piezoelectric element of the nozzle. Ink is ejected from the nozzle whenever it is applied. The drive pulse is applied to the nozzle according to a value “1” indicating ejection (dot on) in the raster data, and is not performed at a value “0” indicating non-ejection (dot off). Therefore, the printer 20 (controller 23) generates the drive pulse in the drive signal generated by the drive signal generation circuit 25 when ink is ejected to the target area (area 2) of the paper S in accordance with the movement in the main scanning backward direction. The timing is adjusted (delayed or advanced) according to the specified adjustment amount. The drive signal to be adjusted here is supplied to the nozzles of the nozzle row (nozzle row corresponding to K ink) used for printing the ruled line pattern LP5 among the nozzle rows of the ink discharge unit 22. This is a drive signal.

  After S340, the process returns to S300 again, and the processing from printing of a plurality of test patterns TP9 is repeated. Of course, in the second and subsequent S300, when pattern printing is performed on the target area, printing is performed based on the drive signal whose drive pulse generation timing has been adjusted in S340. Then, the printing of the test pattern and the adjustment based on the printing result are repeated until the evaluation value converges within the high evaluation range. As a result, even if the relative speed between the ink ejection unit 22 and the paper S during printing varies, the print timing for the target area is set to the deviation of the print result of the target area from the print result of the reference area. However, it is possible to adjust the print timing so that it is the least difficult for the entire sheet to be printed. The variation in the relative speed is considered to occur repeatedly at a certain period due to the rotation characteristics of the carriage motor that moves the ink discharge unit 22 and the rollers and motors of the paper transport unit 21. For this reason, even in the print timing adjustment process, a plurality of test patterns are printed as described above, and the evaluation value is obtained based on the print results of the plurality of test patterns. An appropriate ejection timing of the ink ejection unit 22 is determined.

  After the print timing adjustment process with the area 2 as the target area is completed as described above, the system 60 changes the relationship between the reference area and the target area and repeats the process. That is, the print timing adjustment process is performed in the same manner as described above using the area 2 that has undergone print timing adjustment as a new reference area, the area 3 adjacent to the reference area as the target area, and then the area 3 as a new reference area. The print timing adjustment process is repeated (ball-likely), such that the area 4 adjacent to the area is the target area. As a result, it is possible to obtain the printer 20 that is adjusted to print a ruled line pattern in which the ruled lines in the regions 1, 2, 3, 4,. Some or all of the processes in S310 to S330 in FIG. 27, that is, some or all of the processes such as scoring for each ruled line, calculation of the evaluation value, and specification of the adjustment amount may be performed manually.

  In the above, when the uppermost region among the regions arranged in the vertical direction is set as the first reference region, and the adjusted lower regions are sequentially adjusted as the reference region, the entire region is finally adjusted. did. However, such an adjustment method is only an example. For example, in the print timing adjustment process including the following embodiments, an area adjacent to another area (for example, area 2) on both the upper and lower sides is set as a reference area, and areas above and below the reference area (areas 1 and 3) are respectively set. The print timing is adjusted simultaneously as the target area, and then the print timing adjustment of the area (area 4) adjacent to the three areas after adjustment (areas 1 to 3) is adjusted. ) As a reference area.

Example 15
In Example 15 and other Examples 16 to 21, the parts different from Example 14 will be described. In Example 14, the adjustment was made to match the printing timing of one color having the areas 1, 2, 3, 4,. However, in the printer 20, it is necessary to match the printing timing of all ink colors. In the fifteenth embodiment, therefore, adjustment is performed to match the printing timing between ink colors for each region. In S300, the system 60 prints the test pattern TP10 on a plurality of sheets S.

  FIG. 29 shows the relationship between the ink ejection unit 22 to be adjusted in the fifteenth embodiment and the test pattern TP10 printed on the paper S. The test pattern TP10 is composed of a plurality of ruled line patterns LP6 printed on the paper S at predetermined intervals in the main scanning direction. One ruled line pattern LP6 includes a substantially linear pattern (reference color pattern) formed by substantially continuing a plurality of ruled lines (K ruled lines) that are substantially directed in the nozzle row direction by a reference color (for example, K) and a target color (for example, This is a pattern printed so as to overlap a substantially linear pattern (target color pattern) formed by substantially continuing a plurality of ruled lines (M ruled lines) substantially facing the nozzle row direction in M). Each of the reference color pattern and the target color pattern is formed by substantially continuous ruled lines printed in regions 1, 2, 3, 4,.

  The reference color pattern is printed by setting the ink discharge timing by the nozzle row corresponding to the K ink of the ink discharge portion 22 to the print timing adjusted for each of the regions 1, 2, 3, 4,. Yes. Therefore, all the reference color patterns are basically linear. On the other hand, for the target color pattern, the ink ejection timing by the nozzle row corresponding to the M ink is adjusted for each of the regions 1, 2, 3, 4,. Printing is performed by adjusting according to the printing timing. Therefore, it is basically linear like the reference color pattern.

  The ruled line pattern LP6 is printed based on image data representing a straight reference color pattern and a straight target color pattern at the same position as the reference color pattern. Therefore, the ruled line pattern LP6 is ideally expressed in a state where the reference color pattern and the target color pattern are completely overlapped on the paper S. However, in the ink ejection unit 22, the nozzle row corresponding to the reference color and the nozzle row corresponding to the target color have a certain distance in the direction orthogonal to the nozzle row direction. The relative speed with the paper S varies. Therefore, even when ink is ejected from the nozzle row corresponding to the reference color and the nozzle row corresponding to the target color with a time difference in consideration of the distance between the nozzle rows, the two nozzles are affected by the above variation. In some cases, the ejected dots do not overlap exactly on the paper S, and the deviation between the dots ejected from both nozzles differs for each position of the paper S (for each ruled line pattern LP6). For this reason, the ruled line pattern LP6 on the paper S is expressed as “a pattern printed so that the reference color pattern and the target color pattern overlap”.

  When the test pattern TP10 as described above is printed, in S310, the system 60 performs evaluation based on a plurality of test patterns TP10 and calculates an evaluation value. That is, one of the regions 1, 2, 3, 4... Is set as a target region, and the position of the ruled line of the target color pattern with respect to the ruled line of the reference color pattern is evaluated for each target region. For example, the computer 10 determines whether each ruled line of the target color pattern printed on the area 1 of each sheet S is at the same position as the ruled line of the reference color pattern of the area 1 that should originally be at the same position (whether it is at the center position). ) Evaluation of whether it is located on the right side of the ruled line of the reference color pattern of the region 1 that should originally be in the same position or on the left side of the ruled line of the reference color pattern of the region 1 that should be originally in the same position And give a score. The computer 10 adds up all the points given to the ruled lines of the target color pattern in each area 1 in this way, and sets the total score as the overall evaluation value for the area 1 of the plurality of test patterns TP10.

  In S320, the computer 10 determines whether or not the evaluation value calculated in the latest S310 is within a predetermined high evaluation range (0 points ± predetermined points), and the evaluation value is within the high evaluation range. Ends the evaluation and adjustment for the target region (region 1) at that time. In other words, if the evaluation value is 0 point or a value close to a predetermined value close to 0 point, the difference between the reference color pattern and the target color pattern in the region 1 is the least likely to be seen when viewed across the plurality of sheets S. This is because printing can be said to be executed at each printing timing. On the other hand, in S330, the computer 10 specifies the adjustment amount of the print timing corresponding to the evaluation value calculated in the latest S310. In S340, the computer 10 instructs the printer 20 to adjust the ink ejection timing of the target color for the target area (area 1) according to the adjustment amount specified in the latest S330, and the printer 20 The ink ejection timing is adjusted accordingly.

  That is, the printer 20 (controller 23) generates the drive signal generation circuit 25 when ink is ejected from the nozzle row of the target color (M) to the target area (area 1) of the paper S in the main scanning forward direction. The generation timing of the drive pulse in the drive signal to be adjusted is set (adjusted (delayed or advanced)) according to the specified adjustment amount. After S340, the process returns to S300 again, and the processing from printing a plurality of test patterns TP10 is repeated. As a result, even if the relative speed between the ink ejection unit 22 and the paper S during printing varies, the printing timing of the target color with respect to the printing timing of the reference color in the target area is shifted between the printing results of each other. However, it is possible to adjust the print timing so that it is hard to see the entire sheet. After the print timing adjustment process with the area 1 as the target area is completed in this manner, the system 60 sequentially sets the other areas 2, 3, 4,. repeat. As a result, the printer 20 is adjusted so that the ruled line pattern LP6 in which the linear reference color pattern and the target color pattern substantially overlap can be printed over the plurality of sheets S.

  In the above description, one of the regions 1, 2, 3, 4... Is set as a target region, and the position of the ruled line of the target color pattern with respect to the ruled line of the reference color pattern is evaluated for each target region. However, as described above, since the reference color pattern and the target color pattern constituting the ruled line pattern LP6 are often linear over each area, the evaluation is not performed for each area, but all areas are combined. May be evaluated. In other words, the total area 1, 2, 3, 4... Is regarded as one target area, and the position of the target color pattern with respect to the position of the reference color pattern is evaluated for each ruled line pattern LP6 (one target color pattern). It is also possible to give one score). In the description of the embodiment 15 (the same applies to the embodiments 16, 18, and 20), only the relationship between the reference color (K) and one target color (M) is mentioned, but other ink colors (C, Y, etc.) are sequentially selected as target colors and the same processing as described above is repeated, so that adjustment is performed so that the printing timings of all ink colors are matched.

Example 16
In S300, the system 60 prints the test pattern TP11 on a plurality of sheets S.
FIG. 30 shows the relationship between the ink ejection unit 22 to be adjusted in Example 16 and the test pattern TP11 printed on the paper S. In Example 16, the ink ejection unit 22 is a line head type print head. Similarly to the test pattern TP10, the test pattern TP11 is a plurality of ruled line patterns LP6 (patterns printed so that the reference color pattern and the target color pattern overlap with each other) printed on the paper S at a predetermined interval in the transport direction. ). In the sixteenth embodiment, the ruled line pattern LP6 is printed over the paper width W as the paper S passes under the ink ejection unit 22. In the sixteenth embodiment, as in the fifteenth embodiment, adjustment is performed to match the printing timing between ink colors. For the evaluation of the pattern and the adjustment based on the evaluation, the method of the fifteenth embodiment is applied by regarding the entire plurality of paper planes as one target region.

Example 17
In S300, the system 60 prints the test pattern TP12 on a plurality of sheets S.
FIG. 31 shows the relationship between the ink ejection unit 22 to be adjusted in Example 17 and the test pattern TP12 printed on the paper S. In the seventeenth embodiment, the ink discharge unit 22 is a print head unit (print head unit 22c or print head unit 22d; the same applies hereinafter). In Examples 17 and below of the print timing adjustment processing, the print head unit may be either a print head arranged with ideal alignment or a P / n alignment. Absent. The test pattern TP12 is composed of the same color ruled line pattern LP5 (see FIG. 28) printed on the paper S at a predetermined interval in the transport direction. Like the fourteenth embodiment, the ruled line pattern LP5 is formed by substantially continuous ruled lines of the same color printed in the areas 1, 2, 3, 4... Obtained by dividing the paper S in the vertical direction. However, in the seventeenth embodiment, the ruled lines in the respective regions 1, 2, 3, 4... Are printed by the K ink nozzle rows of the respective print heads constituting the print head unit.

  That is, in the fourteenth embodiment, the timing when a ruled line is printed on a reference area (for example, area 1) with the print head and the ruled line is printed on an adjacent target area (area 2) with the same print head. In the seventeenth embodiment, the timing for printing ruled lines on the reference area (area 1) by the reference print head (reference head, for example, print head 22b1) and the adjacent position are adjusted in the seventeenth embodiment. The print head (target head; print head 22b2) to be adjusted is adjusted to match the timing when the ruled line is printed on the target area (area 2). Specifically, in S340, the printer 20 (controller 23) causes the drive signal to be generated by the drive signal generation circuit 25 when ink is ejected to the target area (area 2) as the paper S is conveyed. The generation timing is adjusted (delayed or advanced) according to the specified adjustment amount. The drive signal to be adjusted here is a drive signal supplied to the nozzles of the nozzle row (nozzle row corresponding to K ink) used for printing the ruled line pattern LP5 in the target head.

  Of course, after making the above adjustment in the relationship between a certain reference head and the target head, the adjusted target head is made the new reference head, and the same adjustment is made in the relationship between the new reference head and the adjacent target head. I do. As a result, the printer 20 is adjusted by the print head unit so that the ruled line pattern in which the ruled lines in the regions 1, 2, 3, 4.

Example 18
In the seventeenth embodiment, the adjustment is made to match the print timings of the nozzle rows of the same color between the print heads in the print head unit. In the eighteenth embodiment, the adjustment is made to match the print timings of the nozzle rows of different colors in the print head unit. I do. In S300, the system 60 prints the test pattern TP13 on a plurality of sheets S.

  FIG. 32 shows the relationship between the ink ejection unit 22 (print head unit) that is the adjustment target in Example 18 and the test pattern TP13 that is printed on the paper S. The test pattern TP13 includes a plurality of ruled line patterns LP6 (see FIGS. 29 and 30) printed on the paper S at predetermined intervals in the transport direction. The ruled line pattern LP6 is a pattern printed so that the reference color pattern based on the reference color (for example, K) and the target color pattern based on the target color (for example, M) are overlapped, as in the fifteenth and sixteenth embodiments. However, the K ruled lines and the M ruled lines of the regions 1, 2, 3, 4... Forming the ruled line pattern LP6 of the eighteenth embodiment depend on the K nozzle rows and M nozzle rows of each print head constituting the print head unit. It is printed. The reference color pattern is printed by setting the ink discharge timing by the nozzle row corresponding to the K ink of each print head to the print timing adjusted for each of the areas 1, 2, 3, 4,. . Therefore, any reference color pattern is basically linear. On the other hand, in the target color pattern, the ink ejection timing by the nozzle row corresponding to the M ink of each print head is set between the areas 1, 2, 3, 4. Printing is performed by adjusting according to the printing timing adjusted every time. Therefore, it is basically linear like the reference color pattern.

  When the test pattern TP13 as described above is printed, in S310, the system 60 performs evaluation based on a plurality of test patterns TP13 and calculates an evaluation value. The processes of S310 to S330 are as described in the fifteenth embodiment. In S340, the computer 10 adjusts the ink ejection timing of the target color of the print head (print head 22b1) corresponding to the target region (for example, the region 1) according to the adjustment amount specified in the latest S330. In response to the instruction, the printer 20 adjusts the timing of ink ejection in accordance with the instruction. When the printer 20 (controller 23) ejects ink from the nozzle row of the target color (M) in the print head (print head 22b1) in the target area (area 1) as the paper S is conveyed, the drive signal generation circuit 25 is used. The generation timing of the drive pulse in the drive signal to be generated is adjusted (delayed or advanced) according to the specified adjustment amount.

  After S340, the process returns to S300 again, and the processing from printing a plurality of test patterns TP13 is repeated. As a result, even if the relative speed between the ink ejection unit 22 and the paper S during printing varies, the printing timing of the target color with respect to the printing timing of the reference color in the target area is shifted between the printing results of each other. However, it is possible to adjust the print timing so that it is the least difficult for the entire sheet to be printed. After the print timing adjustment processing for the area 1 (print head 22b1) as the target area is completed in this manner, the system 60 assigns other areas 2, 3, 4... (Other print heads 22b2, 22b3, 22d4...). The adjustment process of the printing timing of the target color with respect to the reference color is repeated for the target area sequentially.

Example 19
In S300, the system 60 prints the test pattern TP14 on a plurality of sheets S.
FIG. 33 shows the relationship between the ink ejection unit 22 to be adjusted in Example 19 and the test pattern TP14 printed on the paper S. In the nineteenth embodiment, the ink discharge unit 22 is a print head unit group 22e. The test pattern TP14 includes a ruled line pattern LP5 of the same color (for example, K) printed on the paper S at a predetermined interval in the transport direction. A ruled line pattern LP5 according to the nineteenth embodiment is formed by approximately continuous ruled lines printed in regions 1, 2, 3, 4, 5, 6, 7, 8,. Yes. Specifically, the ruled lines in the odd-numbered areas 1, 3, 5, 7,... Are printed by the print heads of the preceding unit, and the ruled lines in the even-numbered areas 2, 4, 6, 8,. Printed by each print head of the line unit.

  That is, in the nineteenth embodiment, the timing when the ruled line is printed in the reference region (region 1) by the reference head (for example, the print head 22b1 of the preceding unit) and the target head (printing of the succeeding unit) adjacent to the ruled line print region The head 22b1) is adjusted to match the timing for printing ruled lines on the target area (area 2). Specifically, in S340, the printer 20 (controller 23) causes the drive signal to be generated by the drive signal generation circuit 25 when ink is ejected to the target area (area 2) as the paper S is conveyed. The generation timing is adjusted (delayed or advanced) according to the specified adjustment amount. The drive signal to be adjusted is a drive signal supplied to the nozzles of the nozzle row (nozzle row corresponding to K ink) used for printing the ruled line pattern LP5 in the target head. Of course, after the above adjustment is performed on the relationship between a certain reference head and the target head, the adjusted target head becomes a new reference head, and the new reference head and the target head whose ruled line print area is adjacent to the new reference head. Similar adjustments are made in the relationship. As a result, the printer 20 extends a ruled line pattern in which the ruled lines in the regions 1, 2, 3, 4, 5, 6, 7, 8,. To be printable.

Example 20
In the nineteenth embodiment, adjustment is performed to adjust the print timing of the nozzle rows of the same color between different print heads in the print head unit group 22e. However, in the twentieth embodiment, the preceding unit and the trailing unit in the print head unit group 22e are adjusted. The adjustment is performed so that the print timings of the nozzle rows of different colors are matched. In S300, the system 60 prints the test pattern TP15 on a plurality of sheets S.

  FIG. 34 shows the relationship between the ink ejection unit 22 (print head unit group 22e) that is the adjustment target in Example 20 and the test pattern TP15 that is printed on the paper S. The test pattern TP15 includes a plurality of ruled line patterns LP6 printed on the paper S at predetermined intervals in the transport direction. The ruled line pattern LP6 is a pattern printed so that the reference color pattern based on the reference color (for example, K) and the target color pattern based on the target color (for example, M) overlap as in the fifteenth, sixteenth, and eighteenth embodiments. The K ruled lines and the M ruled lines in the regions 1, 2, 3, 4... Forming the ruled line pattern LP6 of the twentieth example are K nozzle rows of the print head 22b1 of the preceding unit and M of the print head 22b1 of the succeeding unit. Nozzle row, K nozzle row of preceding unit print head 22b2 and M nozzle row of succeeding unit print head 22b2, K nozzle row of preceding unit print head 22b3 and M of print head 22b3 of following unit Printing is performed by the nozzle row, the K nozzle row of the print head 22d4 of the preceding unit, and the M nozzle row of the print head 22d4 of the subsequent unit.

  The reference color pattern is printed by setting the ink discharge timing by the nozzle row corresponding to the K ink of each print head of the preceding unit as the print timing adjusted for each print head in the nineteenth embodiment. Therefore, any reference color pattern is basically linear. On the other hand, the target color pattern is printed by adjusting the ink discharge timing by the nozzle row corresponding to the M ink of each print head of the succeeding unit according to the print timing adjusted for each print head in the nineteenth embodiment. ing. Therefore, it is basically linear like the reference color pattern.

  When the test pattern TP15 as described above is printed, the system 60 performs an evaluation based on a plurality of test patterns TP15 in S310 and calculates an evaluation value. The processes of S310 to S330 are as described in the fifteenth embodiment. In S340, the computer 10 causes the printer 20 of both print heads (the print head 22b1 of the preceding unit and the print head 22b1 of the subsequent unit) corresponding to the target region (region 1) according to the adjustment amount specified in the latest S330. Among them, an instruction is given to adjust the timing of ink ejection of the target color by the print head of the succeeding unit, and the printer 20 adjusts the timing of ink ejection in accordance with the instruction. When the printer 20 (controller 23) ejects ink from the nozzle row of the target color (M) in the print head 22b1 of the succeeding unit to the target area (area 1) as the paper S is conveyed, the drive signal generation circuit 25 is used. The generation timing of the drive pulse in the drive signal to be generated is adjusted (delayed or advanced) according to the specified adjustment amount.

  After S340, the process returns to S300 again, and the processing from printing of a plurality of test patterns TP15 is repeated. As a result, even if the relative speed between the ink ejection unit 22 and the paper S during printing varies, the printing timing of the target color with respect to the printing timing of the reference color in the target area is shifted between the printing results of each other. However, it is possible to adjust the print timing so that it is the least difficult for the entire sheet to be printed. After the print timing adjustment processing for the area 1 as the target area is completed in this manner, the system 60 performs other areas 2, 3, 4... (The relationship between the print heads 22b2 between the preceding and succeeding units, the print head 22b3. The relationship between the print heads 22d4 and the relationship between the print heads 22d4 is sequentially processed, and the adjustment process of the print timing of the target color with respect to the reference color is repeated.

Example 21
In the above-described Examples 14, 17, and 19, as a ruled line pattern for determining a printing timing shift between areas of the paper S, a ruled line pattern configured by continuing a plurality of ruled lines of the same color facing the nozzle row direction. It is assumed that LP5 is printed on paper S. However, the specific layout of the ruled line pattern LP5 is not limited to that described above. For example, a plurality of ruled lines facing the nozzle direction arranged in one adjacent area among the areas obtained by dividing the paper S in the vertical direction and a plurality of ruled lines oriented in the nozzle direction arranged in the other area. Alternatively, a pattern that is alternately arranged in a comb shape along a direction orthogonal to the nozzle direction may be printed. When such a comb-like pattern is printed, by evaluating whether or not the ruled line of the other region that should be originally positioned at the center position between the ruled lines of one region is accurately positioned, It is possible to determine a shift in print timing between areas.

5). Comprehensive printer adjustment process In the above description, the "tilt adjustment process", "vertical alignment adjustment process", and "print timing adjustment process" have been described separately. Of course, these three processes can be performed continuously. . That is, in the system 60, the inclination adjustment process, the vertical alignment adjustment process, and the print timing adjustment process are continuously performed for the ink discharge unit 22 disposed in the printer 20. As an example, if the ink ejection unit 22 is a print head unit group, the system 60 adjusts the inclination of each of the preceding unit and the succeeding unit, and then performs the vertical adjustment of the succeeding unit with respect to the vertical position of the preceding unit. The alignment adjustment is performed, and finally, the print timing adjustment between the preceding unit and the succeeding unit can be performed.
As described above, according to the present embodiment, even in a situation where there is a conveyance accuracy error such as meandering of the paper S in the printer 20 and a variation in the relative speed, the print result is shifted at each position on the paper S. It is possible to determine the most appropriate attachment angle, vertical position, and printing timing of the ink discharge unit 22 that can be shown in a comprehensive manner.

  35 and 36 show other examples of test patterns that can be printed in the system 60. FIG. FIG. 35 shows a test pattern TP16 printed by the print head unit, and FIG. 36 shows a test pattern TP17 printed by the print head unit. The test pattern TP16 is a pattern including the ruled line pattern LP1 in the test pattern TP3 shown in FIG. 13 and the ruled line pattern LP5 in the test pattern TP12 shown in FIG. The test pattern TP17 is a pattern including the ruled line pattern LP1 in the test pattern TP3 shown in FIG. 14 and the ruled line pattern LP5 in the test pattern TP12 shown in FIG. That is, in the system 60, the test pattern TP16 is printed on the printer 20 including the print head unit as the ink ejection unit 22, and thus necessary for the inclination adjustment process and the print timing adjustment process based on the print result of the test pattern TP16. Each evaluation value can be obtained. In the system 60, the printer 20 having the print head unit is made to print the test pattern TP17, so that it is necessary for the inclination adjustment process, the vertical alignment adjustment process, and the print timing adjustment process based on the print result of the test pattern TP17. Each evaluation value can be obtained.

DESCRIPTION OF SYMBOLS 10 ... Computer, 20 ... Printer, 21 ... Paper conveyance unit, 22 ... Ink discharge part, 22a, 22a1, 22a2, 22a3, 22a4, 22b, 22b1, 22b2, 22b3, 22b4 ... Print head, 22c, 22d ... Print head unit , 22e ... print head unit group, 23 ... controller, 24 ... I / F, 25 ... drive signal generation circuit, 30 ... scanner, 50 ... jig, 60 ... printer adjustment system, 411 ... angle adjustment plate, 412 ... angle adjustment Dial, 413 ... Translation movement plate, 414 ... Translation movement dial

Claims (7)

A predetermined pattern is obtained by ejecting ink from a nozzle of the ink ejection unit to a printing medium using a printing apparatus including an ink ejection unit in which a plurality of nozzle rows in which a plurality of nozzles are arranged in the first direction are arranged in parallel. A printing method for printing
By ejecting ink from each nozzle belonging to a different nozzle row, a plurality of ruled lines represented by the ink ejected from each nozzle and substantially facing a second direction orthogonal to the first direction A printing method comprising printing a ruled line pattern composed of a combination of ruled lines at a plurality of locations on a print medium.   By ejecting ink from nozzles belonging to different nozzle rows and distant from each other in the first direction, the plurality of ruled lines are arranged in a comb-like shape substantially along the first direction. The printing method according to claim 1, wherein a ruled line pattern is printed.   A ruled line pattern in which the plurality of ruled lines are substantially continuous is printed by discharging ink from the nozzles belonging to different nozzle rows and having the same position in the first direction. The printing method according to claim 1.   The printing method according to any one of claims 1 to 3, wherein a ruled line pattern including a combination of ruled lines of the same color is printed by discharging the same color ink from each nozzle that discharges the same color ink. .   4. A ruled line pattern comprising a combination of ruled lines of different colors is printed by ejecting different color inks from nozzles that eject different color inks. Printing method. A printing apparatus that includes an ink ejection unit in which a plurality of nozzle rows in which a plurality of nozzles are arranged in a first direction are arranged in parallel, and prints a predetermined pattern by ejecting ink from a nozzle of the ink ejection unit to a printing medium Because
By ejecting ink from each nozzle belonging to a different nozzle row, a plurality of ruled lines represented by the ink ejected from each nozzle and substantially facing a second direction orthogonal to the first direction A printing apparatus that prints a ruled line pattern composed of a combination of ruled lines at a plurality of locations on a print medium. Printing was performed by ejecting ink from a nozzle of the ink ejection unit to a print medium using a printing apparatus including an ink ejection unit in which a plurality of nozzle rows in which a plurality of nozzles are arranged in the first direction are arranged in parallel. A test pattern,
A plurality of ruled lines that are ejected from each nozzle belonging to different nozzle rows and are represented by the ink ejected from each nozzle, and substantially oriented in a second direction orthogonal to the first direction. A test pattern printed by arranging ruled line patterns composed of combinations of the above at a plurality of locations on a print medium.

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