JP5983116B2 - Discharge adjustment pattern forming method, ink jet head discharge adjusting method, and ink jet printer - Google Patents

Discharge adjustment pattern forming method, ink jet head discharge adjusting method, and ink jet printer Download PDF

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JP5983116B2
JP5983116B2 JP2012153716A JP2012153716A JP5983116B2 JP 5983116 B2 JP5983116 B2 JP 5983116B2 JP 2012153716 A JP2012153716 A JP 2012153716A JP 2012153716 A JP2012153716 A JP 2012153716A JP 5983116 B2 JP5983116 B2 JP 5983116B2
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pattern
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density measurement
determination
nozzles
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JP2014014979A (en
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昌伸 小川
昌伸 小川
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ブラザー工業株式会社
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Description

  The present invention relates to a nozzle ejection adjustment technique for suppressing density unevenness caused by variations in ejection characteristics among a plurality of nozzles of an inkjet head.

  Conventionally, in the field of inkjet printers, there has been a problem that density unevenness occurs in a recorded image formed on a recording medium due to a difference in ink ejection characteristics between a plurality of nozzles of an inkjet head. ing.

  That is, due to factors such as variations in nozzle diameter, variations in flow resistance due to differences in the shape of the ink flow path connected to the nozzles, or variations in the characteristics of actuators that impart discharge energy to ink, the discharge characteristics ( The amount of ejected ink droplets and the velocity of the ejected droplets vary. If the ejection characteristics vary between multiple nozzles, the size of the dots formed on the recording medium will vary, or the dot position (landing position) will deviate from the specified position, resulting in density in the recorded image. Unevenness occurs and image quality is greatly impaired. Thus, conventionally, a technique for suppressing density unevenness caused by variations in ejection characteristics by adjusting the ejection conditions of each of a plurality of nozzles is known.

  Patent Document 1 discloses a method for printing a pattern for acquiring density unevenness information necessary for correcting the ejection characteristic variation among a plurality of nozzles. In this Patent Document 1, first, while moving an inkjet head in a predetermined scanning direction with respect to a recording paper (recording medium), a plurality of nozzles constituting one nozzle row are used on this recording paper. Two fill patterns (patterns for detecting density unevenness) are formed. Next, these patterns are read by the image sensor, and the densities of the portions of the respective patterns formed by the plurality of nozzles are acquired. Based on the density data acquired for each of the plurality of nozzles in this way, density correction for each nozzle is performed during image recording. In the method of Patent Document 1, four density data corresponding to four density measurement patterns are obtained for one nozzle. However, in Patent Document 1, these four density data are averaged. Or there is a description that the mode may be used.

Japanese Patent No. 317849

  By the way, as a recording method using the above-described inkjet head, recording is performed by ejecting ink only when moving in one direction of scanning (referred to as one-way printing), and ink is ejected when moving in both directions. There is a method of recording (referred to as bidirectional printing).

  Among them, in bidirectional printing, ink ejected from one nozzle during movement in one direction (hereinafter also referred to as forward movement) and movement in the other direction (hereinafter also referred to as backward movement). Density unevenness also occurs in the recorded image when the landing position in the scanning direction of the ink ejected on the recording medium is shifted. Therefore, in the discharge adjustment for bidirectional printing, first, ink is ejected from each of the plurality of nozzles in both directions, thereby filling a pattern with a uniform arrangement of many dots formed in both directions (for density measurement). Pattern). However, if there are variations in ejection characteristics among a plurality of nozzles, the bidirectional landing positions of some nozzles are shifted and dots are overlapped, resulting in density unevenness in the pattern. Therefore, from the density unevenness information of the density measurement pattern, the degree of bidirectional landing position deviation at each nozzle is ascertained, and the ejection conditions of each nozzle are adjusted (discharge timing) so that the landing position deviation becomes smaller. And adjustment of discharge energy).

  By the way, in the case of bidirectional printing, there is a further problem that the landing position in both directions is shifted due to the gap between the nozzle of the inkjet head and the recording medium. As shown in FIG. 5 of the embodiment, when the gap between the inkjet head 26 and the recording medium 100 is smaller than the ideal gap (Ga) (Gb), the flight time of the ink droplets ejected from the nozzles 31. The ink ejected in both directions is landed at positions B1 and B2 close to the ejection position. In contrast, when the gap is larger than the ideal gap (Ga) (Gc), the droplet flight time is long, and the ink lands on the positions C1 and C2 far from the ejection position. Accordingly, the ink ejected during the forward movement and the ink ejected during the backward movement should land at the position A in the scanning direction, respectively. When the gap is small, they land at the positions B1 and B2, respectively, and the gap is large. Will land at positions C1 and C2, respectively. Therefore, density unevenness occurs in the image also due to the bi-directional landing position deviation caused by the gap fluctuation.

  If the density measurement pattern is formed in the region where the gap is close to the ideal value Ga on the recording medium, the bidirectional landing position deviation due to the gap fluctuation is reduced, and the influence of this can be eliminated as much as possible. However, in practice, it is difficult to detect at which position of the recording medium the gap is close to the ideal value. Although it may be possible to detect the gap using a dedicated sensor (for example, a laser sensor), it is very time consuming and disadvantageous in terms of cost. Further, the gap may be greatly deviated from the ideal value in any region because the recording medium warps as a whole. However, if the density measurement pattern is formed at an appropriate position on the recording medium, the density measurement pattern may be formed at a location where the gap is significantly different from the ideal value. It is difficult to say that density unevenness can be suppressed even if discharge adjustment is performed based on density data of a density measurement pattern formed in such a place.

  An object of the present invention is to perform discharge adjustment of each nozzle after eliminating the influence of the bi-directional landing position deviation due to gap fluctuation as much as possible.

An ejection adjustment pattern forming method of the present invention is an ejection for performing ejection adjustment of the plurality of nozzles on a recording medium by an inkjet head that ejects ink from the plurality of nozzles while reciprocating along a predetermined scanning direction. A method of forming an adjustment pattern,
A first density measurement pattern formed by the plurality of nozzles when the inkjet head is moved in one direction of the scanning direction in each of the plurality of pattern formation regions of the recording medium, and the scanning direction of the inkjet head A density measurement pattern forming step of forming a density measurement pattern comprising a second density measurement pattern formed by the plurality of nozzles during movement in the other direction;
In each of the plurality of pattern formation regions, a linear first determination pattern formed by the same plurality of nozzles as in forming the density measurement pattern when the inkjet head moves in the one direction, and the inkjet head It consists of a linear second determination pattern formed by the same plurality of nozzles as when forming the density measurement pattern when moving in the other direction, and the first density measurement pattern and the second density of the density measurement pattern A determination pattern forming step for forming a determination pattern for determining how close the positional relationship of the measurement pattern in the scanning direction is to a predetermined ideal state, and
In each pattern formation region, when the ink-jet head moves in the one direction, the discharge conditions of the plurality of nozzles when forming the first density measurement pattern and the first determination pattern are equal, and when the ink-jet head moves in the other direction. The discharge conditions of the plurality of nozzles when forming the second density measurement pattern and the second determination pattern are the same, and the first determination pattern and the second determination pattern are between the plurality of pattern formation regions. The discharge conditions of the plurality of nozzles are made different so that the positional relationship in the scanning direction is shifted.

  In the present invention, a density measurement pattern and a determination pattern for determining the bidirectional positional relationship between the density measurement patterns are formed in each of a plurality of pattern formation regions of the recording medium by so-called bidirectional printing. . In each pattern formation region, the first density measurement pattern formed when the inkjet head moves in one direction and the first determination pattern have the same discharge conditions for a plurality of nozzles, and are formed when the inkjet head moves in the other direction. The discharge conditions of the plurality of nozzles are made equal in the two density measurement pattern and the second determination pattern. On the other hand, the discharge conditions of the plurality of nozzles are intentionally varied so that the positional relationship in the scanning direction of the first determination pattern and the second determination pattern is shifted between the plurality of pattern formation regions. Accordingly, the positional relationship in the scanning direction between the first density measurement pattern and the second density measurement pattern is also shifted.

  As described above, the positional relationship between the first density measurement pattern and the second density measurement pattern is intentionally shifted in the scanning direction between the plurality of pattern formation regions, thereby forming a gap between the inkjet head and the recording medium. Regardless, it is possible to realize a state in which the positional relationship between the first and second density measurement patterns is close to the ideal state in any pattern formation region. It is difficult to determine whether the two density measurement patterns are close to the ideal state. However, since the two determination patterns are linear patterns, these two density measurement patterns are different from the density measurement pattern. It is quite easy to acquire the positional relationship of the determination pattern. Therefore, by grasping the positional relationship between the first and second determination patterns, it is possible to detect which pattern formation region density measurement pattern is close to the ideal state.

  According to the present invention, any pattern formation can be performed regardless of the gap by intentionally shifting the positional relationship between the first density measurement pattern and the second density measurement pattern between the plurality of pattern formation regions in the scanning direction. In the region, it is possible to realize a state in which the positional relationship between the first and second density measurement patterns is close to the ideal state. Further, from the positional relationship between the linear first and second determination patterns, it is possible to easily detect which pattern formation region has the density measurement pattern closest to the ideal state.

1 is a perspective view of an ink jet printer according to an embodiment. It is a top view which shows roughly the internal structure of an inkjet printer. FIG. 2 is a block diagram schematically illustrating an electrical configuration of a printer. It is process drawing of the discharge adjustment of a nozzle. It is a figure explaining the landing position of the ink in bidirectional printing. FIG. 6 is a diagram illustrating a discharge adjustment pattern formed on a recording sheet. It is a detailed view of a discharge adjustment pattern formed in one pattern formation region. It is process drawing of the discharge adjustment of the nozzle in a change form. It is a figure which shows the correlation of the density | concentration of the determination pattern and the density | concentration of the pattern for density measurement in the modification of FIG. It is a figure which shows the mechanism which forms a waveform on the recording paper in another modification.

  Next, an embodiment of the present invention will be described. FIG. 1 is a perspective view of the ink jet printer according to the present embodiment. In the installation state when the ink jet printer 1 shown in FIG. 1 is used, the vertical and horizontal directions and the front and rear directions are defined. FIG. 2 is a plan view schematically showing the internal configuration of the ink jet printer.

  As shown in FIG. 1, the inkjet printer 1 includes a printer housing 2 and a cover 3 that is rotatably attached to the printer housing 2. As shown in FIG. 2, the printer housing 2 accommodates a printer unit 4 that records an image or the like on a recording paper 100. Further, the printer housing 2 is provided with a paper discharge unit 11 that opens forward and discharges the recording paper 100 on which an image is recorded by the printer unit 4. Further, an inclined surface 12 is formed on the front side of the cover 3 of the printer housing 2, and an operation panel 13 is disposed on the inclined surface 12. A lid 14 is attached to the right side portion of the paper discharge unit 11 of the printer housing 2. Behind the lid 14 is a holder 9 on which ink cartridges 17 of four colors (black, yellow, cyan, magenta) are respectively mounted.

  The cover 3 is disposed above the printer casing 2 so as to cover internal mechanisms such as the printer unit 4 accommodated in the printer casing 2. The cover 3 is attached to the printer housing 2 so as to be rotatable up and down at the rear end. Accordingly, it is possible to open the inside of the printer housing 2 by rotating the cover 3 upward during paper jam removal or maintenance inspection. Although not described in detail, the cover 3 is provided with a scanner unit 22 including an image scanner that captures an image recorded on a document. That is, the ink jet printer 1 according to the present embodiment is configured as a multifunction machine capable of executing printing, scanning, copying, and the like.

  Next, the printer unit 4 will be described. As shown in FIG. 2, the recording paper 100 stored in the paper feed cassette 23 is supplied to the printer unit 4 one by one from the back by a paper feed mechanism (not shown). The printer unit 4 conveys the carriage 25 that can reciprocate in the left-right direction (scanning direction), the inkjet head 26 mounted on the carriage 25, and the supplied recording paper 100 forward (conveying direction) along a horizontal plane. A transport mechanism 27 and the like are included.

  A platen 28 that supports the recording paper 100 from below is installed in the printer housing 2 in a horizontal posture. Two guide rails 29 and 30 extending in parallel with the scanning direction are provided above the platen 28. A carriage drive motor 32 is connected to the carriage 25 via an endless belt 39. As the belt 39 travels with the driving force of the carriage drive motor 32, the carriage 25 moves in the scanning direction along the two guide rails 29, 30 in a region facing the recording paper 100 on the platen 28.

  The printer housing 2 is provided with a linear encoder 33 having a large number of light transmitting portions (slits) arranged at intervals in the scanning direction. On the other hand, the carriage 25 is provided with a transmissive encoder sensor 34 having a light emitting element and a light receiving element. The encoder sensor 34 outputs a detection signal every time it detects the light transmitting portion of the linear encoder 33, and the printer 1 recognizes the position of the carriage 25 in the scanning direction from the number of outputs.

  The ink jet head 26 is attached to the lower portion of the carriage 25 with a gap between the ink jet head 26 and the platen 28. A plurality of nozzles 31 are formed on the lower surface of the inkjet head 26 (the surface on the opposite side of the paper surface of FIG. 2). The plurality of nozzles 31 are arranged along the transport direction to form four nozzle rows that respectively eject four colors of ink (black, yellow, cyan, magenta). The inkjet head 26 is connected to the holder 9 by a tube (not shown), and the four colors of ink stored in the four ink cartridges 17 are supplied to the inkjet head 26 through the tube.

  The inkjet head 26 includes an actuator (not shown) that applies ejection energy to the ink in the plurality of nozzles 31. The configuration of the actuator is not particularly limited. For example, a piezoelectric actuator that applies a voltage to the piezoelectric layer and uses the strain generated in the piezoelectric layer can be employed. The ink jet head 26 individually ejects ink from the plurality of nozzles 31 by applying ejection energy to the ink in the plurality of nozzles 31 by an actuator.

  The transport mechanism 27 includes two transport rollers 35 and 36 arranged in the front and rear so as to sandwich the platen 28 and the carriage 25. These two transport rollers 35 and 36 are rotationally driven by a transport motor 37 (see FIG. 3), respectively, and transport the recording paper 100 forward (transport direction) between the inkjet head 26 and the platen 28.

  The above-described printer unit 4 ejects ink from the plurality of nozzles 31 of the inkjet head 26 while moving the carriage 25 in the scanning direction (left-right direction in FIG. 1) on the recording paper 100 on the platen 28. When the movement of the carriage 25 in the scanning direction (also referred to as a pass) is completed, the printer unit 4 transports the recording paper 100 by a predetermined amount in the transport direction by the two transport rollers 35 and 36 of the transport mechanism 27. A desired image is printed on the recording paper 100 by alternately repeating the pass of the carriage 25 and the transport operation of the transport mechanism 27.

  Note that the printer 1 of the present embodiment is a printer capable of bidirectional printing. In bidirectional printing, the inkjet head 26 moves in one direction (rightward in FIG. 2) (referred to as forward movement) and moves in the other direction in the scanning direction (leftward in FIG. 2) ( During the backward movement), ink is ejected from each of the plurality of nozzles 31 to print an image on the recording paper 100.

  Next, the electrical configuration of the printer 1 will be described. FIG. 3 is a block diagram schematically showing the electrical configuration of the printer. A control device 40 that controls the overall control of the inkjet printer 1 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a control circuit, and the like. Various operation units of the printer 1 such as the operation panel 13 and the ink jet head 26 are connected to the control device 40. The components of the control device 40 such as the CPU function as the recording control unit 41, the scanner control unit 42, the discharge condition adjustment unit 43, and the like shown in FIG. The control device 40 is connected to a PC 50 that is an external device.

  An output signal of the encoder sensor 34 is input to the recording control unit 41, and the position of the inkjet head 26 in the scanning direction is always grasped. The recording control unit 41 is a printer unit such as a carriage driving motor 32 that drives the carriage 25, an inkjet head 26, a conveyance motor 37 that drives the conveyance rollers 35 and 36, and the like based on data relating to a recording image input from the PC 50. 4 is controlled to record a desired image on the recording paper 100. In addition, the recording control unit 41 controls each unit of the printer 1 such as the above-described ink jet head 26 to record a later-described ejection adjustment pattern for adjusting the ejection conditions of the plurality of nozzles 31 on the recording paper 100. Is possible.

  The scanner control unit 42 controls the operation of the scanner unit 22 when reading an image. The discharge condition adjustment unit 43 adjusts the discharge conditions of the plurality of nozzles 31 of the ink jet head 26 based on information about a discharge adjustment pattern, which will be described later, acquired by the PC 50 and the scanner 51 which are external devices.

  Hereinafter, the discharge adjustment of the nozzle 31 of the inkjet head 26 will be described. The following ejection adjustment is performed individually for four nozzle rows corresponding to four colors (black, yellow, cyan, magenta) of ink.

(Outline of discharge adjustment)
When the discharge characteristics (droplet discharge amount and droplet discharge speed) are the same among the plurality of nozzles 31 in each nozzle row, ink droplets can be discharged from the plurality of nozzles 31 at the same timing. The same volume droplets discharged from the plurality of nozzles 31 can be landed uniformly on the recording paper 100. At this time, the density of the image formed on the recording paper 100 becomes uniform. However, in practice, the difference between the nozzle diameters between the plurality of nozzles 31, the difference in flow path resistance, or the difference in the actuator characteristics that give ejection energy to the ink in the nozzles 31. In general, the discharge characteristics vary. In this case, the size of droplets discharged from the plurality of nozzles 31 and the landing positions of the droplets vary, resulting in uneven density in the recorded image.

Therefore, the discharge conditions of the plurality of nozzles 31 are adjusted through the following three steps so that the density unevenness due to the discharge characteristic variation of the plurality of nozzles 31 is reduced. FIG. 4 is a process chart of nozzle discharge adjustment.
(1) While moving the inkjet head 26 in the scanning direction, each of the plurality of nozzles 31 ejects ink droplets to form a predetermined ejection adjustment pattern on the recording paper 100 (ejection adjustment pattern forming step).
(2) The discharge adjustment pattern is read by the scanner 51, and density information (information on density unevenness) of this pattern is acquired (density information acquisition step).
(3) The discharge conditions of the plurality of nozzles 31 are adjusted based on the density information of the discharge adjustment pattern (adjustment step).

  The “discharge condition” in the above (3) is a condition that affects the size and landing position deviation of the droplets discharged from each nozzle 31, and specifically, the discharge timing described below. Conditions and discharge energy conditions.

  The ejection timing condition refers to how much the actual ejection timing is shifted with respect to a reference timing predetermined with respect to the predetermined position when ink is landed on the predetermined landing target position of the recording paper 100. This is the amount of time deviation. More specifically, the encoder sensor 34 shown in FIG. 2 detects the amount of time delay until the ink is ejected after the light transmission portion (slit) of the linear encoder corresponding to the predetermined landing target position is detected. Discharge delay amount). When the landing position of a droplet discharged from a certain nozzle 31 deviates from the landing position of another nozzle 31, the landing position is adjusted by adjusting the discharge timing condition of the nozzle 31 whose landing position is shifted. It is possible to align the positions.

  The ejection energy condition is the magnitude of ejection energy given to the ink in each nozzle 31 by the actuator of the inkjet head 26. In the case of the piezoelectric actuator exemplified above, this is the magnitude of the drive voltage applied to the piezoelectric layer for each nozzle 31. Even if the discharge energy conditions are the same among the plurality of nozzles 31, if the degree of energy loss is different due to a difference in flow path resistance or the like, the size and liquid of the liquid droplets discharged from the plurality of nozzles 31, respectively. Drop speed is different. Therefore, in such a case, it is possible to align the droplet size and the droplet velocity (that is, the droplet landing position) by adjusting the discharge energy condition.

(Discharge adjustment pattern formation step)
First, a step of forming a discharge adjustment pattern on the recording paper 100 will be described. Here, in order to suppress density unevenness of an image recorded by bidirectional printing, the discharge adjustment pattern is also formed by bidirectional printing. By the way, the gap with the inkjet head 26 is not necessarily constant over the entire area of the recording paper 100, and the gap is an ideal value (assumed value) depending on the location when the recording paper 100 is lifted, warped, or undulated. May be different.

  FIG. 5 is a diagram for explaining ink landing positions in bidirectional printing. As shown in FIG. 5, when the gap is an ideal value (Ga), it is assumed that both ink droplets ejected in both forward and backward movements land on the position A. However, when the gap is smaller than the ideal value (Ga) (Gb), the ink droplets ejected in both directions land at positions B1 and B2, which are closer to the ejection position than the position A, respectively. When the gap is larger than the ideal value (Ga) (Gc), the ink droplets ejected in both directions land at positions C1 and C2 farther from the ejection position than the position A, respectively. Therefore, ideally, the ink ejected during the forward movement and the ink ejected during the backward movement should each land on the ideal position A. If the gap is small, they land on the positions B1 and B2, respectively. If it is larger, it will land at positions C1 and C2, respectively. As described above, in bidirectional printing, not only variations in ejection characteristics among the plurality of nozzles 31 but also deviations in the bidirectional landing position occur due to gaps.

  If the discharge adjustment pattern is formed without considering the above-mentioned gap problem, is the density unevenness existing in the discharge adjustment pattern due to variations in discharge characteristics among the plurality of nozzles 31 or due to the gap? I don't know. Therefore, when performing ejection adjustment in bidirectional printing, it is necessary to eliminate as much as possible the impact of the landing position deviation due to the gap.

  FIG. 6 is a diagram showing a discharge adjustment pattern formed on the recording paper. As shown in FIG. 6, a plurality of ejection adjustment patterns 61 are formed in a plurality of areas (pattern formation area 60) of the recording paper 100. The plurality of pattern formation regions 60 are regions that are regularly arranged in the scanning direction and the conveyance direction, respectively. That is, a plurality of ejection adjustment patterns 61 arranged in a matrix in the scanning direction and the conveyance direction are formed on the recording paper 100.

  FIG. 7 is a detailed view of the discharge adjustment pattern formed in one pattern formation region. As shown in FIG. 7, the ejection adjustment pattern 61 in one pattern formation region 60 includes a density measurement pattern 62 and two determination patterns 63 so as to sandwich the density measurement pattern 62 in the scanning direction. The following discharge adjustment pattern 61 is formed by the recording control unit 41 of the control device 40 controlling the printer unit 4.

  The density measurement pattern 62 is a fill pattern composed of a first density measurement pattern 62a and a second density measurement pattern 62b. The first density measurement pattern 62a is formed by ejecting ink from a plurality of nozzles 31 constituting one nozzle row 38 during the forward movement (FWD) of the inkjet head 26, and is formed at predetermined intervals in the scanning direction (details). Is composed of a large number of dot rows (indicated by thin hatching) arranged in an interval of twice the nozzle arrangement pitch of the nozzle row 38. The second density measurement pattern 62b is composed of a large number of dot rows (indicated by dark hatching) formed by ejecting ink from the plurality of nozzles 31 in the same manner when the inkjet head 26 is moved backward (RVS). The dot row of the second density measurement pattern 62b is formed so as to be positioned between the two dot rows of the first density measurement pattern 62a. It is preferable to form a plurality of density measurement patterns 62 so as to have a width of about 10 to 20 mm in the scanning direction. A plurality of density data can be acquired for each nozzle 31 by providing a certain width (number). It is desirable that the density data of a certain nozzle 31 in each pattern formation region 60 is obtained by averaging a plurality of density data.

  As shown in FIG. 7A, a state where the dots of the second density measurement pattern 62b are located in the middle of the two dots of the first density measurement pattern 62a is particularly referred to as an “ideal state”. When all the dots are in the ideal state, the density measurement pattern 62 is a filled pattern with a uniform dot arrangement (density) in which a large number of dots formed in both directions are arranged at equal intervals in the scanning direction and the conveyance direction. Become. “Dots are uniformly arranged” means that the distance between dots is equal between a dot and surrounding dots adjacent to the dot. In this ideal state, the dots are uniformly arranged only when the discharge characteristics of the plurality of nozzles 31 are all equal, and when there are variations in the discharge characteristics, of course, the positions of some of the dots Will shift. In other words, in this ideal state, when the discharge characteristics of the plurality of nozzles 31 are all equal, the dots are arranged uniformly, and conversely, the discharge characteristics of the plurality of nozzles 31 vary. It becomes easier to grasp density unevenness. That is, “dots are uniformly arranged” means that the discharge characteristics of the plurality of nozzles 31 are assumed to be equal, and the discharge characteristics of the plurality of nozzles 31 before discharge adjustment are the same. Even when the pattern is formed in a dispersed state, it does not mean that the dots are arranged uniformly.

  As shown in FIG. 7, dummy patterns 64, which are the same fill patterns as the density measurement pattern 62, are formed on the upstream side and the downstream side in the conveyance direction of the density measurement pattern 62. The dummy pattern 64 on the upstream side in the transport direction is formed by another path before the density measurement pattern 62 is formed, and the downstream dummy pattern 64 is formed by another path after the density measurement pattern 62 is formed. . When the upstream and downstream edges (portions formed by both ends of the nozzle row 38) of the density measurement pattern 62 are adjacent to a white area where no pattern is formed, the density When the measurement pattern 62 is read by the scanner 51, a reading error increases due to reflection of the white recording paper 100 or the like. Therefore, the reading error can be suppressed by forming the dummy pattern 64 so as to be adjacent to the density measurement pattern 62 as described above.

  The determination pattern 63 includes a first determination pattern 63a and a second determination pattern 63b. The first determination pattern 63a is a linear pattern (dot row) formed by discharging ink from a plurality of nozzles 31 constituting one nozzle row 38 when the inkjet head 26 moves forward, and extending in the transport direction. is there. The second determination pattern 63b is a linear pattern (dot row) that is formed by ejecting ink from the plurality of nozzles 31 when the inkjet head 26 moves backward, and extending in the transport direction. The second determination pattern 63b is formed to overlap the first determination pattern 63a in the scanning direction. The determination pattern 63 is formed using the same nozzle 31 (with the same color) as the density measurement pattern 62 in the scanning direction. The determination pattern 63 is formed away from the density measurement pattern 62 by a predetermined distance in the scanning direction. By forming the determination pattern 63 away from the density measurement pattern 62 in this way, it is difficult to be affected by the density measurement pattern 62 at the time of reading, and it is desirable that the distance is about 3 to 5 mm. Since the determination pattern 63 determines landing deviation as will be described later, it may be at least one linear pattern as shown in FIG. 7, but there may be a plurality of determination patterns.

  Further, in one pattern formation region 60, the first density measurement pattern 62a and the first determination pattern 63a formed at the time of forward movement, the discharge conditions (that is, the discharge timing conditions (discharge delay)) of the plurality of nozzles 31, and Make the discharge energy conditions the same. Similarly, the discharge conditions of the plurality of nozzles 31 are made the same for the second density measurement pattern 62b and the second determination pattern 63b formed during the backward movement.

  On the other hand, the discharge conditions of the plurality of nozzles 31 are made different between the plurality of pattern formation regions 60 so that the positional relationship in the scanning direction between the first determination pattern 63a and the second determination pattern 63b is shifted. Here, since the discharge conditions of the first determination pattern 63a and the first density measurement pattern 62a are the same, and the discharge conditions of the second determination pattern 63b and the second density measurement pattern 62b are the same, a plurality of pattern formations are performed. When the ejection conditions are changed so that the scanning direction positions of the two determination patterns 63a and 63b are shifted between the regions 60, the first density measurement pattern 62a and the second density measurement pattern 62b are also shifted in the scanning direction by the same amount.

  In particular, in this embodiment, as shown in FIG. 7A, the first density measurement pattern 62a and the second density measurement pattern 62b of the density measurement pattern 62 are in an ideal state in which dots are uniformly arranged. In addition, the first determination pattern 63a and the second determination pattern 63b are completely overlapped. That is, if the positional relationship between the two density measurement patterns 62a and 62b of the density measurement pattern 62 is deviated from the ideal state, the first determination pattern 63a and the second determination pattern 63b are also deviated from the state where both are equally arranged. . FIG. 7B shows an example of the discharge adjustment pattern 61 when the density measurement pattern 62 is deviated from the ideal state. For example, as shown in FIG. 7B, the second determination pattern 63b becomes the first determination pattern 63a as shown in FIG. 7B if the discharge delay at the time of reverse movement (RVS) is made smaller than that in FIG. The second density measurement pattern 62b is also shifted to the right by the same amount with respect to the first density measurement pattern 62a. Alternatively, it can also be realized by increasing the ejection speed by increasing the ejection energy applied to the ink during the backward movement.

  As shown in FIG. 7A, when the density measurement pattern 62 is in an ideal state, the ink landing area is wide because there is little overlap between the first density measurement pattern 62a and the second density measurement pattern 62b. The density of the density measurement pattern 62 is increased. On the other hand, regarding the determination pattern 63, since the first determination pattern 63a and the second determination pattern 63b are completely overlapped, the thickness of the determination pattern 63 is small. On the other hand, as shown in FIG. 7B, when the density measurement pattern 62 is deviated from the ideal state, the first density measurement pattern 62a and the second density measurement pattern 62b partially overlap each other. The area decreases and the density of the density measurement pattern 62 decreases. On the other hand, with respect to the determination pattern 63, the thickness of the determination pattern 63 increases due to the displacement of the positions of the first determination pattern 63a and the second determination pattern 63b.

  If the variation in the gap between the inkjet head 26 and the recording paper 100 is not taken into consideration, it is assumed that the gap has an ideal value (assumed value), and the two density measurement patterns 62a and 62b respectively formed in both directions are assumed. Therefore, the discharge conditions of the plurality of nozzles 31 at the time of forward movement and at the time of backward movement may be determined so that the positional relationship in the ideal state is obtained. However, when the gap is different from the ideal value, the positional relationship between the two density measurement patterns 62a and 62b is not an ideal state in the discharge adjustment pattern 61 formed in such a place. In contrast, in the present embodiment, the discharge conditions of the plurality of nozzles 31 are slightly changed between the plurality of pattern formation regions 60, and the scanning direction positions of the two density measurement patterns 62a and 62b are intentionally shifted. Yes. Accordingly, it is possible to realize a state in which the positional relationship between the two density measurement patterns 62a and 62b is close to the ideal state in any one of the plurality of pattern formation regions 60 regardless of whether the gap is an ideal value. In addition, the degree to which the positional relationship between the two density measurement patterns 62a and 62b is close to the ideal state can be determined from the thickness of the corresponding determination pattern 63.

(Concentration information acquisition step)
As shown in FIG. 4, the density information acquisition step includes a reading step and a determination step. In the reading step, the plurality of ejection adjustment patterns 61 formed on the recording paper 100 are read by the scanner 51 connected to the PC 50. The pattern information read by the scanner 51 is sent to the PC 50. For each of the plurality of ejection adjustment patterns 61, the PC 50 acquires the density information of the density measurement pattern 62 portion and the determination pattern 63 portion formed by each nozzle 31 in association with each other. For example, in FIG. 7A, with respect to the nozzle 31 positioned third from the top in the drawing, the density information of the density measurement pattern 62 surrounded by the thick frame X formed by this nozzle 31 and the thick frame Y Are obtained in association with the density information of the determination pattern 63 surrounded by. In addition, it can be recognized as follows, for example, to which nozzle 31 the density information of a part of the density measurement pattern 62 and the determination pattern 63 corresponds. First, in the previous pattern formation step, a reference pattern is formed in each of the plurality of pattern formation regions 60 using a predetermined nozzle 31 in addition to the discharge adjustment pattern 61. In addition, in this density information acquisition step, based on how far the density measurement pattern 62 and the determination pattern 63 are apart from the reference pattern, the nozzle 31 that formed the part is specified.

  In the determination step, it is determined in which pattern formation region 60 the density measurement pattern 62 formed is close to the ideal state. However, it is difficult to determine whether the positional relationship in the scanning direction between the two density measurement patterns 62a and 62b formed in two directions is close to the ideal state in the density measurement pattern 62 that is a filled pattern. Therefore, the determination is made from the positional relationship in the scanning direction between the first determination pattern 63a and the second determination pattern 63b of the determination pattern 63. Since these two determination patterns 63a and 63b are linear patterns, the positional deviation amount in the scanning direction of the first determination pattern 63a and the second determination pattern 63b is grasped unlike the two density measurement patterns 62a and 62b. It's pretty easy to do.

  Specifically, for each nozzle 31, the PC 50 has the lowest density in the portion of the determination pattern 63 formed by the nozzle 31 among the plurality of pattern formation regions 60 (the positional deviation between the two determination patterns 63 a and 63 b). The pattern forming region 60 is specified that has the smallest amount and the smallest judgment pattern 63 thickness. The density information of the density measurement pattern 62 in the specified pattern formation region 60 is used as information used for the discharge adjustment of the nozzle 31. Further, the above determination is performed for all of the plurality of nozzles 31. In this manner, the density information of the density measurement pattern 62 from which the influence of the gap variation is eliminated can be acquired for the plurality of nozzles 31.

  In the present embodiment, when the two density measurement patterns 62a and 62b of the density measurement pattern 62 are in an ideal state, the determination pattern 63 is such that the first determination pattern 63a and the second determination pattern 63b completely overlap. Is forming. When the first determination pattern 63a and the second determination pattern 63b are completely overlapped, the thickness of the determination pattern 63 is the thinnest. Therefore, by comparing the thicknesses of the plurality of determination patterns 63 respectively formed in the plurality of pattern formation regions 60, it is possible to easily determine which density measurement pattern 62 is closest to the ideal state for each nozzle 31.

  The above determination is based on the premise that the gap is almost the same between the formation region of the density measurement pattern 62 and the formation region of the determination pattern 63 in each pattern formation region 60. Therefore, it is preferable to form the density measurement pattern 62 and the determination pattern 63 in one pattern formation region 60 as close as possible. In the present embodiment, two determination patterns 63 are formed on both sides of the density measurement pattern 62 in the scanning direction. As a result, when the gaps are not equal on both sides of the density measurement pattern 62, the state can be grasped by the determination patterns 63 on both sides. For example, even if the density of one judgment pattern 63 is low, if the density of the other judgment pattern 63 is quite high, the gap is greatly different on both sides of the density measurement pattern 62 in this pattern formation region 60. Therefore, the density information of the density measurement pattern 62 is not used for the discharge adjustment. Note that it is not essential to form the determination patterns 63 on both sides of the density measurement pattern 62, and the determination patterns 63 may be formed only on either the left or right side.

  In the above description, the PC 50 connected to the scanner 51 specifies the density measurement pattern 62 formed under the condition closest to the ideal state from the plurality of ejection adjustment patterns 61 read by the scanner 51. Note that the above determination may be performed by the control device 40 of the printer 1 instead of the PC 50.

(Adjustment step)
In the adjustment step, the discharge condition adjustment unit 43 of the control device 40 performs plural printing when performing bidirectional printing based on the density information of the density measurement pattern 62 for each of the plurality of nozzles 31 sent from the PC 50. The discharge conditions of the nozzles 31 are respectively adjusted. That is, the discharge timing condition (discharge delay) or the discharge energy condition of the plurality of nozzles 31 is adjusted so that the density unevenness of the density measurement pattern 62 is reduced. Since the discharge adjustment of the nozzle 31 based on the density information is already a well-known technique, further detailed description is omitted.

  As described above, in this embodiment, the gap is formed by intentionally shifting the positional relationship between the first density measurement pattern 62a and the second density measurement pattern 62b between the plurality of pattern formation regions 60 in the scanning direction. Regardless of the ideal value, it is possible to realize a state in which the density measurement pattern 62 is close to the ideal state in any of the pattern formation regions 60. Further, even when there is no region where the gap has an ideal value, it is possible to realize a state close to the ideal state. Further, from the positional relationship in the scanning direction between the linear first determination pattern 63a and the second determination pattern 63b, it is possible to easily detect which pattern formation region 62 in the pattern formation region 60 is closest to the ideal state. Then, by using the density measurement pattern 62 that is closest to the ideal state, the discharge adjustment of the plurality of nozzles 31 can be performed in a state where the influence of the gap fluctuation is eliminated as much as possible.

  As shown in FIG. 6, in this embodiment, a plurality of pattern formation regions 60 are arranged in the scanning direction and the transport direction. For this reason, it is possible to deal with both fluctuations in the scanning direction of the gap and fluctuations in the transport direction. For example, when a plurality of pattern formation regions 60 are arranged only in the scanning direction and the gap varies greatly in the transport direction, the ejection adjustment pattern 61 is formed only in a place where the gap is extremely large or small. It is possible that it will be done. In this respect, the above-described problem does not occur when a plurality of pattern formation regions 60 are arranged in the transport direction.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] In the embodiment, for each of the plurality of nozzles, it is individually determined which pattern formation region the density information of the density measurement pattern formed in is adopted. However, if the gap hardly fluctuates in the nozzle arrangement direction (transport direction in the above embodiment) and the conditions regarding the gap are substantially the same for all the nozzles 31 in one nozzle row 38, the above-mentioned is true for all the nozzles 31. There is no need to make a determination. For example, for only one nozzle 31, the density measurement pattern 62 formed in a state closest to the ideal state is specified, and all the nozzles are determined based on the density information of the specified one density measurement pattern 62. You may perform 31 discharge adjustment.

2] In the above-described embodiment, in the density information acquisition step, the density measurement pattern 62 close to the ideal state is specified (selected) from the plurality of density measurement patterns 62 respectively formed in the plurality of pattern formation regions 60. It was. However, in this case, the selected density measurement pattern 62 may be closest to the ideal state among the plurality of density measurement patterns 62, but the viewpoint of improving the accuracy of the discharge adjustment in the subsequent adjustment step. Then, it is desirable to acquire density information of the pattern when it is formed in a state close to the ideal state. Of course, if a large number of density measurement patterns 62 are formed, the accuracy is improved, but there is a limit to this. Therefore, as described below, in the density information acquisition step, the density of the density measurement pattern 62 in the ideal state may be estimated using information of the plurality of ejection adjustment patterns 61 read by the scanner.

  FIG. 8 is a process chart of nozzle discharge adjustment in this modified embodiment. In FIG. 8, the discharge adjustment pattern forming step is a step of forming the discharge adjustment pattern 61 of FIGS. 6 and 7 of the above-described embodiment and is the same as that of the above-described embodiment. The density information acquisition step includes a reading step, a correlation acquisition step, and an estimation step.

  In the reading step, the plurality of ejection adjustment patterns 61 formed on the recording paper 100 are read by the scanner 51 connected to the PC 50 as in the above embodiment. Then, the PC 50 acquires, for each of the plurality of ejection adjustment patterns 61, the density information of the density measurement pattern 62 portion and the determination pattern 63 portion formed by each nozzle 31 in association with each other.

  Next, in the correlation acquisition step, the correlation between the density of the plurality of determination patterns 63 obtained for each nozzle 31 and the density of the corresponding plurality of density measurement patterns 62 is obtained. FIG. 9 shows an example of the correlation between the density of the determination pattern and the density of the density measurement pattern. As shown in FIG. 9, with respect to each nozzle 31, a plurality of pieces of density information are plotted using the density of the determination pattern 63 on the horizontal axis and the density of the density measurement pattern 62 on the vertical axis, and the least square method or the like is used. Interpolate with an appropriate interpolation function. Further, the correlation as shown in FIG. 9 is acquired for each of the plurality of nozzles 31.

In the estimation step, the density of the density measurement pattern 62 in the ideal state is estimated using the correlation between the density of the determination pattern 63 and the density measurement pattern 62 in FIG. When the density measurement pattern 62 is in an ideal state, the first determination pattern 63a and the second determination pattern 63b of the determination pattern 63 are completely overlapped, so the density (thickness) of the determination pattern 63 at that time is determined in advance. Predictable. Therefore, as shown in FIG. 9, when the determination pattern 63 has an ideal density, the density of the density measurement pattern 62 is obtained, and this density is estimated as the density in the ideal state. Then, this density estimation is performed for each of the plurality of nozzles 31 using the respective correlations.
Similar to the above-described embodiment, the correlation acquisition step and the estimation step described above may be executed by the PC 50 connected to the scanner 51, or may be executed by the control device 40 of the printer 1.

  Next, in the adjustment step shown in FIG. 9, the discharge conditions are adjusted for each of the plurality of nozzles 31 using the density information of the density measurement pattern 62 estimated in the estimation step. In this modified form, the density information in the ideal state of the density measurement pattern 62 is estimated, so that the estimated density information can be used to perform discharge adjustment with high accuracy while eliminating the influence of gap fluctuation almost completely. It becomes.

3] In the above embodiment, the determination pattern 63 is formed so that the first determination pattern 63a and the second determination pattern 63b completely overlap when the density measurement pattern 62 is in the ideal state. The determination pattern 63a and the second determination pattern 63b may be arranged apart from each other by a predetermined distance in the scanning direction. In this case, when the positional relationship between the first density measurement pattern 62a and the second density measurement pattern 62b of the density measurement pattern 62 is deviated from the ideal state, the first determination pattern 63a and the second determination pattern 63b are similarly shifted. Thus, the scanning direction separation distance of the first and second determination patterns changes. Accordingly, by detecting the distance in the scanning direction between the first determination pattern 63a and the second determination pattern 63b in each of the plurality of pattern formation regions 60, the density measurement pattern 62 in which pattern formation region 60 is close to the ideal state. Can be determined.

4] In the above-described embodiment, one determination pattern 63 has one first determination pattern 63a and one second determination pattern 63b. However, the first determination pattern 63a and the second determination pattern 63b are You may have multiple each. For example, with only one first determination pattern 63a and one second determination pattern 63b, the thickness of the line is too thin, and the positional relationship between the first determination pattern 63a and the second determination pattern 63b is the thickness (density). ), It is effective to form a plurality of first determination patterns 63a and a plurality of second determination patterns 63b.

5] When the printer 1 has a scanner function as in the above embodiment, the discharge adjustment pattern 61 printed on the recording paper 100 by the printer 1 is read by the scanner unit 22 of the printer 1 and further acquired by the scanner unit 22. The information may be processed by the control device 40 of the printer 1. In this case, printing of the discharge adjustment pattern 61 onto the recording paper 100, reading of the discharge adjustment pattern 61, and adjustment of the discharge conditions of the plurality of nozzles 31 can all be performed by one printer 1.

6] In order to prevent warping or the like of the recording paper 100 during conveyance, there is a technique for intentionally forming a wave shape on the recording paper 100 in which crests and troughs are alternately arranged in the scanning direction. For example, as shown in FIG. 10, a plate 71 having a plurality of ribs 70 a is arranged below the recording paper 100 at a position upstream of the platen 28 (see FIG. 2) in the transport direction. A plurality of claw portions 71 are arranged on the top. A plurality of ribs 70a and a plurality of claw portions 71 are alternately arranged in the scanning direction. The recording paper 100 placed on the plurality of ribs 70 a of the plate is suppressed from above by the plurality of claw portions 71. As a result, the recording paper 100 has a crest 101 at the position of the rib 70a, a trough 102 at the position of the claw 71, and a wave shape in which the crest 101 and the trough 102 are alternately arranged in the scanning direction. . In this embodiment, the gap between the inkjet head 26 and the recording paper 100 varies greatly in the scanning direction. Therefore, it is very significant to apply the present invention that can form the density measuring pattern 62 in the ideal state regardless of the gap in the printer 1 having the above configuration.

  As shown in FIG. 10, when a wave shape is intentionally formed on the recording paper 100, the crest portion 101 a (the portion where the rib 70 a is in contact) or the trough portion 102 of the crest portion 101 of the recording paper 100. It is preferable to form the discharge adjustment pattern 61 in the valley bottom portion 102a (the portion where the claw portion 71 is in contact). The change rate of the gap in the scanning direction is small in the peak portion 101a of the peak portion 101 and the valley bottom portion 102a of the valley portion 102. Therefore, if the discharge adjustment pattern 61 is formed by using the peak portion 101a or the valley bottom portion 102a as one pattern formation region 60, the density measurement pattern 62 and the determination pattern 63 in the one pattern formation region 60 are formed. The gaps at the positions where they are formed can be made almost equal.

7] The pattern forming area for forming the ejection adjustment pattern of the recording paper is not limited to the form in which the pattern is aligned in the scanning direction and the carrying direction as shown in FIG. For example, the pattern formation regions may be arranged only in the scanning direction, or the pattern formation regions may be arranged only in the transport direction. Furthermore, the pattern formation regions may be arranged in a direction (for example, a diagonal direction of the recording paper) that intersects the scanning direction and the conveyance direction.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 26 Inkjet head 31 Nozzle 40 Control apparatus 41 Recording control part 43 Discharge condition adjustment part 60 Pattern formation area 61 Discharge adjustment pattern 62 Density measurement pattern 62a First density measurement pattern 62b Second density measurement pattern 63 Determination pattern 63a First 1 judgment pattern 63b 2nd judgment pattern 70a rib 71 nail part 100 recording paper 101 mountain part 101a mountain peak part 102 valley part 102a valley bottom part

Claims (8)

  1. A method of forming a discharge adjustment pattern for performing discharge adjustment of the plurality of nozzles on a recording medium by an inkjet head that discharges ink from a plurality of nozzles while reciprocating along a predetermined scanning direction,
    A first density measurement pattern formed by the plurality of nozzles when the inkjet head is moved in one direction of the scanning direction in each of the plurality of pattern formation regions of the recording medium, and the scanning direction of the inkjet head A density measurement pattern forming step of forming a density measurement pattern comprising a second density measurement pattern formed by the plurality of nozzles during movement in the other direction;
    In each of the plurality of pattern formation regions, a linear first determination pattern formed by the same plurality of nozzles as in forming the density measurement pattern when the inkjet head moves in the one direction, and the inkjet head It consists of a linear second determination pattern formed by the same plurality of nozzles as when forming the density measurement pattern when moving in the other direction, and the first density measurement pattern and the second density of the density measurement pattern A determination pattern forming step for forming a determination pattern for determining how close the positional relationship of the measurement pattern in the scanning direction is to a predetermined ideal state, and
    In each pattern formation region, when the ink-jet head moves in the one direction, the discharge conditions of the plurality of nozzles when forming the first density measurement pattern and the first determination pattern are equal, and when the ink-jet head moves in the other direction. The discharge conditions of the plurality of nozzles when forming the second density measurement pattern and the second determination pattern are equal,
    Furthermore, the discharge conditions of the plurality of nozzles are varied so that the positional relationship in the scanning direction of the first determination pattern and the second determination pattern is shifted between the plurality of pattern formation regions ,
    Ejection characterized in that the density measurement pattern when all the dots of the first density measurement pattern and the second density measurement pattern are in the ideal state is a fill pattern in which the dots are uniformly arranged Adjustment pattern forming method.
  2. A method of forming a discharge adjustment pattern for performing discharge adjustment of the plurality of nozzles on a recording medium by an inkjet head that discharges ink from a plurality of nozzles while reciprocating along a predetermined scanning direction,
    A first density measurement pattern formed by the plurality of nozzles when the inkjet head is moved in one direction of the scanning direction in each of the plurality of pattern formation regions of the recording medium, and the scanning direction of the inkjet head A density measurement pattern forming step of forming a density measurement pattern comprising a second density measurement pattern formed by the plurality of nozzles during movement in the other direction;
    In each of the plurality of pattern formation regions, a linear first determination pattern formed by the same plurality of nozzles as in forming the density measurement pattern when the inkjet head moves in the one direction, and the inkjet head It consists of a linear second determination pattern formed by the same plurality of nozzles as when forming the density measurement pattern when moving in the other direction, and the first density measurement pattern and the second density of the density measurement pattern A determination pattern forming step for forming a determination pattern for determining how close the positional relationship of the measurement pattern in the scanning direction is to a predetermined ideal state, and
    In each pattern formation region, when the ink-jet head moves in the one direction, the discharge conditions of the plurality of nozzles when forming the first density measurement pattern and the first determination pattern are equal, and when the ink-jet head moves in the other direction. The discharge conditions of the plurality of nozzles when forming the second density measurement pattern and the second determination pattern are equal,
    Furthermore, the discharge conditions of the plurality of nozzles are varied so that the positional relationship in the scanning direction of the first determination pattern and the second determination pattern is shifted between the plurality of pattern formation regions ,
    The method of forming an ejection adjustment pattern , wherein the plurality of pattern formation regions are arranged in the scanning direction .
  3. A method of forming a discharge adjustment pattern for performing discharge adjustment of the plurality of nozzles on a recording medium by an inkjet head that discharges ink from a plurality of nozzles while reciprocating along a predetermined scanning direction,
    A first density measurement pattern formed by the plurality of nozzles when the inkjet head is moved in one direction of the scanning direction in each of the plurality of pattern formation regions of the recording medium, and the scanning direction of the inkjet head A density measurement pattern forming step of forming a density measurement pattern comprising a second density measurement pattern formed by the plurality of nozzles during movement in the other direction;
    In each of the plurality of pattern formation regions, a linear first determination pattern formed by the same plurality of nozzles as in forming the density measurement pattern when the inkjet head moves in the one direction, and the inkjet head It consists of a linear second determination pattern formed by the same plurality of nozzles as when forming the density measurement pattern when moving in the other direction, and the first density measurement pattern and the second density of the density measurement pattern A determination pattern forming step for forming a determination pattern for determining how close the positional relationship of the measurement pattern in the scanning direction is to a predetermined ideal state, and
    In each pattern formation region, when the ink-jet head moves in the one direction, the discharge conditions of the plurality of nozzles when forming the first density measurement pattern and the first determination pattern are equal, and when the ink-jet head moves in the other direction. The discharge conditions of the plurality of nozzles when forming the second density measurement pattern and the second determination pattern are equal,
    Furthermore, the discharge conditions of the plurality of nozzles are varied so that the positional relationship in the scanning direction of the first determination pattern and the second determination pattern is shifted between the plurality of pattern formation regions ,
    In each pattern formation region, a dummy pattern is formed adjacent to the density measurement pattern in a direction orthogonal to the scanning direction,
    The method of forming an ejection adjustment pattern , wherein the determination pattern is formed at a predetermined distance from the density measurement pattern in the scanning direction .
  4. When the first density measurement pattern and the second density measurement pattern of the density measurement pattern are in the ideal state, the first judgment pattern and the second judgment pattern are completely corresponding to the judgment pattern corresponding thereto. The discharge adjustment pattern forming method according to claim 1, wherein the discharge adjustment pattern forming method overlaps with the discharge adjustment pattern.
  5. In the determination pattern forming step, a discharge adjustment pattern according to claim 1-4 where one of the density measuring pattern so as to sandwich in the scanning direction, and forming two of said decision pattern Forming method.
  6.   The discharge adjustment pattern forming method according to claim 1, wherein the plurality of pattern formation regions are arranged in a transport direction of the recording medium that intersects the scanning direction.
  7. Using any of the discharge adjustment pattern forming method discharge adjustment pattern formed on a recording medium by the claims 1-6, a method of performing discharge adjustment of said plurality of nozzles of the ink jet head,
    A reading step of reading the density measurement pattern and the determination pattern for each of the plurality of pattern formation regions of the recording medium;
    Of the plurality of the determination patterns read in the reading step, information on the amount of shift in the scanning direction between the first determination pattern and the second determination pattern is the most suitable among the plurality of density measurement patterns in the ideal state. A determination step of determining a near density measurement pattern;
    An adjustment step of adjusting discharge conditions for each of the plurality of nozzles using density information of the density measurement pattern determined in the determination step;
    An ejection adjustment method for an ink jet head, comprising:
  8. Using any of the discharge adjustment pattern forming method discharge adjustment pattern formed on a recording medium by the claims 1-6, a method of performing discharge adjustment of said plurality of nozzles of the ink jet head,
    A reading step of reading the density measurement pattern and the determination pattern for each of the plurality of pattern formation regions of the recording medium;
    Information on the amount of shift in the scanning direction of the first determination pattern and the second determination pattern of the plurality of determination patterns read in the reading step, and a plurality of density measurement patterns respectively corresponding to the plurality of determination patterns using the density information, the correlation acquisition step of using the relationship before Symbol positional displacement amount of information of the second determination pattern and the first determination pattern and the density information,
    Using the correlation between the amount of positional displacement information and the density information of the second determination pattern as before Symbol first determination pattern obtained by the correlation acquisition step, the concentration of the density measuring pattern of the ideal state An estimation step for estimating information;
    An adjustment step of adjusting discharge conditions for each of the plurality of nozzles using the density information estimated in the estimation step;
    An ejection adjustment method for an ink jet head, comprising:

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EP13161411.7A EP2684700B1 (en) 2012-07-09 2013-03-27 Method of forming ink ejection adjustment pattern, ink ejection adjustment method for inkjet head and inkjet printer
US13/853,289 US8974028B2 (en) 2012-07-09 2013-03-29 Method of forming ink ejection adjustment pattern, ink ejection adjustment method for inkjet head and inkjet printer
US14/624,939 US9186886B2 (en) 2012-07-09 2015-02-18 Method of forming ink ejection adjustment pattern, ink ejection adjustment method for inkjet head and inkjet printer

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