JP2015091667A - Ink jet recording apparatus and recording position adjusting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a shift in a transport direction as a whole of a plurality of nozzle rows in an ink jet recording apparatus that performs recording using a recording head having a plurality of nozzle rows. An adjustment value is preferentially set for a nozzle row in which a deviation amount in the transport direction exceeds a threshold value. The adjustment value is determined by setting an adjustment value that minimizes the sum of the deviation amounts of the plurality of nozzle arrays. [Selection] Figure 3

Description

  The present invention relates to an ink jet recording apparatus that records an image on a recording medium by ejecting ink from a recording head, and a recording position adjusting method.

  2. Description of the Related Art Conventionally, in an ink jet recording apparatus, a technique for correcting a shift in a dot recording position (ink droplet landing position) on a recording medium is known. Japanese Patent Application Laid-Open No. 2004-228688 controls the ink ejection timing according to the position in the scanning direction of the carriage on which the recording head is mounted, so that even when the distance between the carriage and the recording medium varies in the scanning direction, A technique capable of accurately correcting the recording position regardless of the position is disclosed.

JP-A-11-240146

  However, the amount of deviation of the ink droplet landing position varies at each position within the scanning range of the carriage, not only in the scanning direction, but also in a direction that intersects the scanning direction (also in the transport direction). . As the cause, for example, the posture of the carriage fluctuates during scanning.

  FIG. 15 is a schematic diagram for explaining the posture change of the carriage. In the figure, 8 is a main rail, 6 is a sub rail, 4 is a carriage, 1 is a recording head, and 23 is a recording position shift. For example, assuming that the main rail 8 is slightly bent, the posture of the carriage 1 is inclined with respect to the platen as shown by the oblique lines at a certain position, and parallel to the platen at a certain position. Here, in the recording head mounted on the carriage 1, a plurality of nozzle arrays are arranged shifted in the scanning direction. When recording is performed at the same position on the recording medium with each nozzle array, the ejection timing of both nozzles is It is shifted by the time considering the interval between the rows and the carriage scanning speed. Therefore, when the two nozzle rows print at the same position on the printing medium, the positions in the scanning direction at the time when each nozzle row ejects ink are different, and the posture of the carriage may be different. In this way, as a result of different carriage postures, the positions of dots to be recorded at the same position are shifted in the transport direction.

  If the landing position is shifted in the scanning direction, it can be easily adjusted by adjusting the ejection timing. Therefore, the adjustment value can be set at each position in the scanning range. However, since the deviation of the landing position in the transport direction must shift the data in the transport direction or change the use range of the nozzles, it is within the accuracy range obtained over the entire scanning range using one adjustment value. It is desired that the landing position shift is contained in

  By the way, in the case of adjusting the landing position deviation in the scanning direction in a recording apparatus having a recording head in which three or more nozzle rows are formed, an adjustment value is set for each of the remaining nozzle rows based on a specific nozzle row. It will be. Here, for example, it is assumed that there are nozzle row A and nozzle row B as the reference nozzle row and other nozzle rows. At this time, if the landing position in the conveying direction of the nozzle row A is optimally matched to the reference nozzle row, the deviation of the landing positions of the nozzle row A and the nozzle row B may be further deteriorated. In addition, the deviation between the nozzle row A and the nozzle row B may affect the image more than the reference nozzle row and the nozzle row A. In such a case, the adjustment values of the nozzle row A and the nozzle row B have priority. It is necessary to set optimally. Therefore, in a printing apparatus having three or more nozzle rows, when determining the adjustment value for each nozzle row, it is necessary to determine the adjustment value in consideration of the priority order.

  Therefore, the present invention sets an adjustment value for adjusting the deviation of the landing position in the conveyance direction for a plurality of nozzle rows, thereby reducing the deviation amount as a whole for each nozzle row over the scanning range, and An object of the present invention is to provide a recording apparatus and a recording position adjusting method capable of adjusting the position.

  The present invention relates to an ink jet recording apparatus that performs recording by causing a recording head in which a plurality of nozzle rows for ejecting ink are arranged in a predetermined direction to scan in a scanning direction and transporting a recording medium in a direction intersecting the predetermined direction. The acquisition means for acquiring the displacement amount of the recording position for each of the plurality of nozzle rows in the intersecting direction at the plurality of positions in the predetermined direction, and the displacement of the recording position for each of the acquired nozzle rows A determining unit that compares the amount with a threshold value and determines a nozzle row that exceeds the threshold value; and a setting unit that preferentially sets an adjustment value for adjusting a printing position for a nozzle row that exceeds the threshold value. It is characterized by having.

  According to the present invention, by setting an adjustment value for adjusting the deviation of the landing position in the transport direction for a plurality of nozzle rows, it is possible to reduce the amount of deviation of each nozzle row as a whole over the scanning range. .

1 is a perspective view of an ink jet recording apparatus to which the present invention can be applied. The schematic diagram for demonstrating a reflection type optical sensor. The typical flowchart of this embodiment. The figure which shows the landing position shift profile of each color. The figure which applied the threshold value to the landing position shift profile. The figure which shows the landing deviation of each color after implementing priority adjustment. 1 is a configuration diagram of a recording head to which the present invention can be applied. The figure explaining the relationship between a nozzle position and landing deviation. The figure explaining the pattern which acquires landing position shift on the basis of an inflection point. The figure which shows the fluctuation | variation of the landing position shift amount to which the adjustment value of the reference color reference is applied. The figure which shows the fluctuation | variation of the landing position deviation | shift amount to which the adjustment value of multiple color average is applied. FIG. 2 is a schematic block diagram of a control circuit of the recording apparatus of FIG. The figure which shows the fluctuation | variation of the landing position deviation | shift amount of a carriage direction. The figure which shows the fluctuation | variation of the landing position shift | offset | difference amount in the commanded printing area. The figure explaining the attitude | position fluctuation | variation of a carriage. The schematic diagram which shows the relationship of the landing position about 4 colors. The schematic diagram explaining the case where a landing position is adjusted by changing the adjustment order. 10 is a flowchart for calculating an adjustment value for target toning.

  FIG. 1 is an external perspective view of an ink jet recording apparatus to which the present invention can be applied. A manual insertion slot 88 is provided on the front surface of the ink jet recording apparatus (hereinafter also simply referred to as a recording apparatus) 2, and a roll paper cassette 89 that can be opened and closed to the front surface is provided below the manual insertion slot 88. A recording medium such as recording paper is supplied into the recording apparatus from the manual insertion slot 88 or the roll paper cassette 89. The ink jet recording apparatus includes an apparatus main body 94 supported by two legs 93, a stacker 90 on which the discharged recording medium is stacked, and a transparent and openable upper cover 91 through which the inside can be seen. An operation panel 5, an ink supply unit, and an ink tank are disposed on the right side of the apparatus main body 94.

  The recording apparatus 2 includes an arrow B that intersects a predetermined direction with a recording medium such as a carriage 4 and recording paper that are guided and supported so as to be capable of reciprocating scanning in the width direction (arrow A direction, scanning direction) of the recording medium corresponding to a predetermined direction. A transport roller 70 for transporting in the direction (transport direction) is provided. Furthermore, a carriage motor (not shown) and a carriage belt (hereinafter referred to as a belt) 270 for reciprocating the carriage 4 in the direction of arrow A, and a recording head 1 mounted on the carriage 4 are provided. In addition, a suction-type ink recovery unit 9 is provided for supplying ink and for eliminating ink discharge defects due to clogging of the discharge ports of the recording head 1. In addition, a linear scale is provided in the scanning direction, and the relative movement distance of the carriage 4 is detected by counting output pulses of an encoder sensor (not shown). Based on this information, the ink discharge timing is also determined. Be controlled.

  In the case of this recording apparatus, the carriage 4 has a configuration in which four recording heads 1 integrated with three colors are mounted on 12 color inks in order to perform color recording on a recording medium. With the above configuration, after the recording medium is conveyed to the predetermined recording start position by the conveyance roller 70, the recording head is scanned in the main scanning direction by the carriage 4, and the recording medium is conveyed in the sub-scanning direction by the conveyance roller 70. Recording is performed by repeating the operation.

  In other words, the carriage 4 is moved in the direction of arrow A shown in FIG. 1 by the belt 270 and a carriage motor (not shown), and recording is performed on the recording medium. When the carriage 4 is returned to the position before being scanned (home position), the recording medium is conveyed in the sub-scanning direction (the arrow B direction shown in FIG. 1) by the conveying roller. Thereafter, the carriage is scanned again in the direction of arrow A in FIG. 1 to record an image, a character, or the like on the recording medium. When the above operation is repeated and the recording for one sheet of recording medium is completed, the recording medium is discharged into the stacker 90, and the recording for one sheet is completed.

  The carriage 4 is provided with a reflective optical sensor 30 (not shown), which detects the density of the adjustment pattern recorded on the recording medium (paper) in order to detect the recording position shift. Fulfill. By combining the scanning of the carriage 4 in the scanning direction and the paper transporting operation in the sub-scanning direction, the optical sensor 30 can detect the density of the adjustment pattern recorded on the paper. The reflective optical sensor 30 may be used for detecting the edge of the paper.

  FIG. 2 is a schematic diagram for explaining the reflective optical sensor 30 corresponding to the optical detection means. The reflective optical sensor 30 includes a light emitting unit 11 and a light receiving unit 12, and is used to detect optical information of an object. The light Iin 16 emitted from the light emitting unit 11 is reflected by the surface of the recording medium 3. The reflected light includes regular reflection and irregular reflection, but it is desirable to detect the irregular reflection light Iref 17 in order to detect the density of the image recorded on the recording medium 3 more accurately. Therefore, the light receiving unit 12 is arranged so as to be different from the incident angle of light from the light emitting unit 11. The detection signal obtained by the detection is transmitted to the electric board of the recording apparatus.

  Here, in order to perform registration adjustment for a head that discharges all ink including main ink and special color ink such as C, M, Y, and K, the light emitting unit is a white LED or three-color LED, and the light receiving unit is A photodiode having sensitivity in the visible light region is used. However, in the case of detecting the relationship between the relative recording position and the density of the overlapping recording, when adjusting the nozzle rows of different inks, a three-color LED capable of selecting a color with high detection sensitivity is used. Is more preferred. Although details will be described later, in detecting the density of an image recorded on the recording medium 3, it is not necessary to detect the absolute value of the density, as long as the relative density can be detected. Further, it is only necessary to have a detection resolution enough to detect a relative density difference in each pattern (also referred to as a patch) belonging to an adjustment pattern group described later.

  Furthermore, the stability of the detection system including the reflective optical sensor 30 may be of a level that does not affect the detected density difference until the set of adjustment pattern groups is detected. The sensitivity adjustment is performed, for example, by moving the optical sensor 30 to a non-recording portion of the paper. As an adjustment method, there is a method of adjusting the light emission intensity of the light emitting unit 11 so that the detection level becomes an upper limit value or adjusting the gain of the detection amplifier in the light receiving unit 12. Although sensitivity adjustment is not essential, it is suitable as a method for improving S / N and increasing detection accuracy.

  The spatial resolution of the reflective optical sensor 30 is desirably a resolution that can detect an area smaller than the recording area of one adjustment pattern. In multi-pass printing in which a predetermined area is completed by a plurality of printing scans, when two pattern groups are recorded adjacent to each other in the scanning direction and the sub-scanning direction, the recording width in the sub-scanning direction is It becomes smaller according to the number of passes. For this reason, the resolution of the sensor is limited by the number of recording passes. The number of recording passes (recording width) may be determined from the resolution of the sensor. Further, when the distance between the recording medium and the reflection type optical sensor changes, the amount of light received by the phototransistor changes, and the distance between the recording medium and the carriage 4 (corresponding to the distance between the recording medium and the recording head) also changes. It can be detected.

  FIG. 12 is a schematic block diagram of a control circuit of the recording apparatus 2. The controller 400 is a main control unit, and includes, for example, a CPU 401 in the form of a microcomputer, a ROM 403 storing programs, required tables, and other fixed data, and a RAM 405 provided with an area for developing image data, a work area, and the like. The host device 410 is a supply source of image data. Specifically, it may be in the form of a reader unit for image reading, in addition to a computer for creating and processing data such as images related to image recording. Image data, other commands, status signals, and the like are transmitted / received to / from the controller 400 via an interface (I / F) 412. The operation unit 420 is a switch group that receives an instruction input from the operator. There is a power switch 422 and a recovery switch 426 for instructing activation of suction recovery. In addition, a registration adjustment start switch 427 for manually performing registration adjustment, a registration adjustment value setting input unit 429 for manually inputting the adjustment value, and the like are provided. The sensor group 430 is a sensor group for detecting the state of the apparatus. The sensor group 430 is provided in the above-described reflective optical sensor 30, the photocoupler 109 for detecting the home position, and an appropriate part for detecting the environmental temperature. A temperature sensor 434 and the like are included.

  The head driver 440 is a driver that drives a discharge heater in the recording head 1 according to print data or the like. The head driver 440 includes a shift register that aligns print data according to the position of the discharge heater, and a latch circuit that latches at appropriate timing. Furthermore, in addition to the logic circuit element that operates the discharge heater in synchronization with the drive timing signal, there is a timing setting unit that appropriately sets the drive timing (discharge timing) for dot recording position adjustment.

FIG. 7 shows an array of nozzle rows of 12 colors in the present embodiment. In this embodiment, a three-color integrated recording head that can be attached to and detached from the carriage is used, and {PBk, Gy, PGy}, {B, G, R}, {PM, M, MBk}, {Y, The recording heads are mounted on the carriage 4 so as to have an arrangement of C, PC}.
The details of the recording position adjustment method of the present embodiment will be described below.

  FIG. 3 is a flowchart of the recording position adjustment method of the present embodiment. The processing according to this flow can be executed at an arbitrary timing such as when the recording apparatus is activated for the first time or when the user gives an instruction via the host or the input unit of the recording apparatus. First, in step S3-1, a landing position deviation profile for each color is generated. This landing position deviation profile is generally used to obtain landing position deviations in the transport direction for all combinations of 12 colors, but here, deviations of combinations involving MBk are not obtained. This is because PBk and MBk are black used by switching according to the application (mode), and in the present embodiment, it is assumed that a landing position deviation profile is created under a condition (mode) in which MBk is not used. .

  Next, a method for determining the landing position deviation of each color by forming a test pattern will be described. If an adjustment value is obtained by forming a test pattern over the entire scanning direction for each of all 11 color combinations, a large amount of recording medium and time are consumed. Therefore, in the present embodiment, the following method that can easily obtain the adjustment value is adopted.

  FIG. 9 is a diagram for explaining a test pattern in the present embodiment. In the figure, a main rail 8 is supported by a main rail support member 7, and a carriage (not shown) scans the main rail to perform recording on a recording medium. In the present embodiment, the adjustment pattern 13 for detecting the landing position deviation is recorded at the position of the recording medium 3 corresponding to the main rail support member 7. This is because the posture change of the carriage tends to occur in the main rail support member 7. Therefore, an adjustment pattern is formed only at a position where the carriage posture variation is generated, and the landing position deviation amount between the support members 7 (corresponding to the inflection point of the deviation amount deviation) is complemented by linear approximation. Can be assumed. In the present embodiment, the maximum landing position deviation amount among the landing position deviation amounts in the entire scanning region is acquired as the deviation amount between the colors.

  Note that various conventionally known patterns can be used as the adjustment pattern 13 for obtaining the amount of deviation in the transport direction. For example, for the two target colors, ruled lines with different shift amounts between the respective colors are formed in a plurality of stages, and the shift amount can be obtained based on the shift amount when the two ruled lines are the most straight lines. . Alternatively, it is possible to form a plurality of blocks in which the reflection optical density changes by changing the shift amount between the two colors, and to obtain the shift amount based on the change in the optical density.

  FIG. 8 shows a relationship diagram of the landing deviation amount (conveying direction) of each nozzle row with reference to the nozzle row PC. Since the carriage 4 is supported by the rail at a symmetrical position from the center position, the landing position shift tendency is different for the six colors on the right side and the six colors on the left side from the center of the carriage. That is, the variation in the amount of landing deviation due to the variation in the posture of the carriage differs between the right side and the left side with respect to the center of the carriage. In particular, when there are a plurality of recording heads integrated with a plurality of colors as in this embodiment and the distance between the nozzle rows is large, the influence is significant. On the other hand, in the nozzle row belonging to the right recording head or the nozzle row belonging to the left recording head with respect to the center of the carriage, the landing position deviation amount exhibits the same behavior. This is because the carriage posture is determined at the center of the two support positions supported by the support member 18.

  For example, there are six colors, PM, M, MBk, Y, C, and PC, on the left recording head, and the deviation of these six colors is almost linearly approximated (see the lower part of FIG. 8). Therefore, by acquiring only two kinds of deviation amounts of PM and PC (that is, the maximum landing deviation amount in the recording range) from the adjustment pattern shown in FIG. 9, and obtaining the landing position deviation amounts of other colors by calculation, It is possible to simplify the acquisition of the deviation amount (adjustment value). Similarly, the shift amounts of the six colors belonging to the right recording head are also acquired.

  FIG. 4 is an example of the maximum deviation amount in the carrying direction and the landing position deviation profile for the combination of 11 colors obtained by the above method, and shows the deviation amount in the carrying direction between the colors in units of pixels. Since the landing position deviation amount due to the carriage posture variation increases as the distance between the nozzle rows increases, as a tendency, the outermost nozzle row PBk and PC combination has a landing position deviation amount due to the carriage posture variation. The biggest. On the other hand, the shift amount between two colors of adjacent nozzle rows in the same recording head is relatively small.

  Subsequently, in step S3-2, a threshold between colors is applied to the created landing position deviation profile. In the present embodiment, the threshold value of the combination of two colors related to light color and yellow is set to 1.5, and the threshold value of other color combinations is set to 1.0. This threshold value is a value set to determine whether or not the landing position deviation between the colors is within an allowable range. For combinations of colors with a high frequency of occurrence of superimposition and combinations of colors that are conspicuous, by lowering the threshold (1.0), the range of allowable deviation is reduced, and high-quality image recording is maintained. I can do it. Note that the combination of colors with a high occurrence frequency of superposition is not limited to light colors but may be dark colors.

  FIG. 5 shows a result of applying a threshold between colors to the landing position deviation profile of FIG. In the figure, a portion indicated by a thick frame is a combination in which the deviation amount is equal to or greater than a threshold value. In this embodiment, the threshold is exceeded in a total of 11 combinations such as a combination of PBk-Pc, C, and M.

  Next, in step S3-3, it is determined whether each of all combinations of 11 colors is equal to or less than the threshold value or exceeds the threshold value. As described above, in the case of this embodiment, the threshold is exceeded in a total of 11 combinations. If the threshold value is not exceeded for all combinations, the process for adjusting the landing position is not required, so the position adjustment process is not performed in step S3-5. On the other hand, if the threshold is exceeded in a specific combination, the landing position deviation in all 11 colors can be optimally adjusted by changing the adjustment priority in that combination.

  Next, in step S3-4, the adjustment value is preferentially determined for the combination exceeding the threshold by increasing the priority of adjustment. In this embodiment, the reference color is PBk. First, adjustment values for cyan C, magenta M, and photocyan Pc exceeding the threshold are determined in combination with the reference color (PBk). Next, with reference to the adjustment values cyan C and magenta M, an adjustment value for a color exceeding the reference value is determined. This is because priority is given to the basic colors (C, M, Y, K) of color superposition. Of these basic colors, K determines the adjustment value with the highest priority, and Y is difficult to visually recognize, so the adjustment value is determined by lowering the priority order from C and M. Therefore, in this example, next, an adjustment value of Gy is determined by C, M, and Gy, and an adjustment value of B is determined by C, M, and B. Further, an adjustment value of G is determined by G using C, M and B, and an adjustment value of R is determined by C, M and R.

  Here, a method for determining the adjustment value will be described. FIG. 16 is a schematic diagram simulating the relationship between the landing positions of the four colors PBk, C, M, and B in this example. In the figure, B positioned above the rightmost PBk indicates that the landing position is shifted to the + side with respect to PBk, and conversely, C and M positioned below PBk are This indicates that the landing position is shifted to the-side with respect to PBk. Further, the shift amount of each color based on the reference color PBk is divided into two components, a shift amount 24 depending on the nozzle row and a maximum value 25 of the landing position shift amount in the scanning region of the carriage. The amount of deviation 24 depending on the nozzle row depends on the manufacturing tolerance of each color nozzle row, but here the amount of deviation is the same for each color. On the other hand, the maximum value 25 of the landing position deviation amount in the scanning region of the carriage is a deviation amount based on PBk, and increases as the distance between the nozzle rows from PBk increases. Among the combinations of the four colors (PBk, C, M, B), the maximum shift amount 26 is a shift amount between C and B.

  FIG. 17 is a diagram for explaining an adjustment value determination procedure according to this embodiment. As described above, first, cyan C and magenta M are adjusted in combination with the reference color (PBk). Thereafter, the adjustment value of B is not determined so that the deviation amount from PBk is small, but is decided so that the deviation amount is small with respect to C and M. In this case, since the adjustment value is set so as to minimize the landing position deviation amount with respect to C and M, the landing position of B is adjusted as shown in FIG. If this adjustment is performed, the landing position deviation amount between PBk and B increases, but the total landing position deviation amount in the combination between PBk, C, M, and B becomes smaller than that in FIG. In this way, instead of using a fixed order for determining the adjustment value, it is determined from the maximum value of the landing position deviation amount in the scanning region of the carriage in consideration of the deviation amount depending on the nozzle row. The amount of landing position deviation at can be reduced.

On the other hand, in step S3-5, the landing positions are adjusted in the normal order as set for the combinations below the threshold. Here, an adjustment value between the reference color (PBk) and the remaining colors may be determined. In the present embodiment, the landing position is adjusted in the following order.
(1) Adjust PBk-C and determine the impact adjustment value for C. (2) Adjust PBk-M and determine the impact adjustment value for M. (3) Adjust PBk-PC and set the impact adjustment value for PC. Determination (4) Adjust MC-Gy, determine Gy impact adjustment value (5) Adjust MC-B, determine B impact adjustment value (6) Adjust MC-R , R landing adjustment value is determined (7) M-CG is adjusted, G landing adjustment value is determined (8) Other colors (PM, PGy, Y) are matched with PBk (reference color)

  FIG. 6 shows the shift amount between the colors adjusted by the above flow. According to the present embodiment, by increasing the priority of the position adjustment of the color combination having a large amount of landing position deviation, the landing position deviation of all colors can be adjusted in a balanced manner, and the accuracy of the landing position deviation in the transport direction as a plurality of colors as a whole is achieved. Can be increased. In addition, as a conventionally known method for correcting the dot landing position in the transport direction, the image data may be shifted in the transport direction in units of pixels in accordance with the adjustment value, or the used nozzle range may be different. Any correction method may be used.

  Here, a specific method for determining the landing position adjustment values for a plurality of colors described with reference to FIGS. Here, in order to simplify the description, a case where the landing adjustment value that minimizes the landing position deviation between the three colors is determined is shown. FIG. 18 shows a flowchart for calculating the adjustment values of the three colors.

  First, in step S18-1, an adjustment target color is set. Here, the adjustment target colors are A, B, and C. According to the examples shown in FIGS. 16 and 17, the adjustment target colors A, B, and C correspond to C, M, and B, respectively. Further, among the adjustment target colors, a color for which an adjustment value is set in advance is set as a reference color, and a color for determining the adjustment color by this processing is set as an adjustment color. In the example of the flowchart shown in FIG. 3, C and M whose adjustment values have already been determined for the reference color (PBk) are the reference colors, and B which determines the adjustment value in relation to C and M corresponds to the adjustment color. . However, in the following description, it is assumed that the reference color is one color (reference color 1) and the adjustment colors are two colors (adjustment color 1, adjustment color 2). Note that even if the nozzles are of the same color and are arranged differently in the carriage, they can be processed in the same manner by treating them as different colors in this processing.

  Next, in step S18-2, an average deviation value in the carriage direction (CR direction) of the color to be adjusted is acquired, and an adjustment value for the average deviation amount is determined and corrected.

  First, an average value of shift amounts in the entire CR direction for each color is calculated. This can be done by taking the average of the deviations measured at multiple locations in the CR direction as shown in FIG. Then, the landing positions of the reference color, the adjustment color 1 and the adjustment color 2 when the adjustment value for the average deviation amount is applied are calculated. Since the applied landing adjustment value is a unit of nozzle resolution (1200 dpi: 21 μm in this embodiment), the average adjustment value is hardly “0” with respect to the reference color.

  FIG. 10 shows the landing position deviation amount after measuring the landing position deviation for each of a plurality of points in the scanning region and applying the landing adjustment value using the average adjustment value. Here, when the adjustment value is determined so that the deviation of the average landing position deviation amount in the carriage scanning area of each color is minimized, the deviation amount with respect to the reference color can be minimized. For example, the maximum deviation amount between the reference color and the adjustment color 1 is about 30 μm near the CR position of 600 mm. The maximum deviation between the reference color and the adjustment color 2 is about 20 μm near the CR position 850 mm. For simplification of explanation, the reference color is shown as having no variation in the amount of deviation in the CR direction.

  Next, in step S18-3, the shift amounts of the adjustment target colors A, B, and C in the initial state, that is, the state in which the adjustment value simply based on the reference color is applied are calculated. Specifically, variable N is used, and variable N = 1, An = A, Bn = B, and Cn = C. Here, An, Bn, and Cn are respective adjustment values, A is the landing deviation amount for each carriage position of the reference color, B is the landing deviation amount for each carriage position of adjustment color 1, and C is the carriage of adjustment color 2 The landing deviation amount for each position is shown. That is, for each color, an adjustment value that takes into account a single shift amount is set.

  In the next step S18-4, the maximum deviation amount for each CR position in An, Bn, and Cn is calculated. In the case of FIG. 10, for example, at the CR position of 200 mm, the combination of the maximum deviation colors between the three colors is the adjustment color 1 and the adjustment color 2, and the deviation amount is about 22 μm. On the other hand, in the vicinity of the CR position of 800 mm, the combination of the reference color and the adjustment color 1 is the combination of the maximum deviation amounts at that position, and the deviation amount is about 19 μm. As described above, although the combinations of the maximum shift amounts are different for each CR position, the maximum shift amount at each position is calculated.

  Next, in step S18-5, the maximum shift amount (Rn) in the entire CR region is set. In the example of FIG. 10, the maximum shift amount is the shift between the adjustment color 1 and the adjustment color 2 near the CR position 600, and the size thereof is about 45 μm.

Next, in step S18-6, it is determined whether N = 5. If N is not 5, 1 is added to N in step S18-7, and the process returns to step S18-4. In this flow, N = 1 to 5 are divided into cases, and the maximum deviation amount is calculated respectively. Each of N = 1 to 5 is as follows.
When N = 1 An = A, Bn = B, Cn = C
When N = 2 An = A, Bn = B + 1, Cn = C
When N = 3 An = A, Bn = B, Cn = C + 1
When N = 4 An = A, Bn = B−1, Cn = C
When N = 5 An = A, Bn = B, Cn = C−1
“1” that is added to or subtracted from B or C in the above equation is the adjustment resolution (1200 dpi: 21 μm) of the landing position adjustment.

  According to this flow, when N = 1, the maximum landing position deviation amount in the initial state of the adjustment target color (adjustment value is determined for each color alone) is calculated. Further, in the case of N = 2, the maximum landing position deviation amount in a state where the adjustment value of +1 is applied to B (adjustment color 1) among the three adjustment target colors is calculated. Similarly, the maximum deviation amount can be calculated in a state where the adjustment value of +1 and the adjustment value of −1 are applied to B (adjustment color 1) and C (adjustment color 2). In this manner, in step S18-4, the maximum deviation amount for each CR position in An, Bn, and Cn in cases other than N = 1 is calculated (step S18-5).

  FIG. 11 shows the landing position deviation amount of each color when N = 5 (An = A, Bn = B, Cn = C−1). Here, the combination of the maximum deviation amounts at the CR position of 600 mm is the adjustment color 1 and the adjustment color 2. On the other hand, in the vicinity of 800 mm, the combination of the reference color and the adjustment color 2 is a combination of the maximum deviation amounts. In the example of FIG. 11, the maximum deviation amount is about 35 μm of the combination of the reference color and the adjustment color 2 in the vicinity of the CR position of 800 mm. This is because the shift amount of the adjustment color 2 with respect to the reference color is worse than that of the example of FIG. 10, but when the combination of three colors is considered, the landing adjustment value of FIG. The amount is smaller than the example of FIG.

  In step S18-9, adjustment values An, Bn, and Cn that minimize Rn are set. In this example, the maximum deviation amount Rn is 35 μm when N = 5, and is smaller than N = 1 or other N cases. Accordingly, in such a case, adjustment values An = A, Bn = B, and Cn = C−1 that minimize the landing deviation amount for all combinations of the three target adjustment colors over the entire carriage scanning region. Select.

As described above, in view of the landing position deviation amount between a plurality of colors and for each carriage position, the optimum landing adjustment value is not necessarily the value that minimizes the deviation amount of each color with respect to the reference color. That is, if multiple colors are combined with the reference color, the landing position deviation may deteriorate between the other colors. By determining the adjustment value as in the present embodiment, it is possible to perform an adjustment with a small deviation amount for all the adjustment target colors (three colors in this example).
As described above, in this embodiment, the shift amount for each combination of the plurality of nozzle arrays is compared with the threshold value. Then, by determining the adjustment value preferentially for combinations exceeding the threshold value, it is possible to reduce the deviation amount in the plurality of nozzle rows as the sum thereof. Also, as shown in FIG. 18, when determining adjustment values for a plurality of nozzle rows, the respective adjustment values are determined so that the sum of landing position deviations of the plurality of nozzle rows is minimized. Thereby, it is possible to set an adjustment value that minimizes a shift in the transport direction of a plurality of colors.

(Other)
The adjustment value obtained by the above method is basically determined based on a combination of the landing deviation amount and the ink color in the entire carriage. However, when the recording range in which the carriage scans and records is different (for example, when the size of the recording medium is different), the adjustment value may be varied depending on the print area. FIG. 13 shows the relationship between the landing positions after applying the landing adjustment so that the landing position deviation is minimized in the entire scanning range of the carriage for the reference color and the adjustment color. In the figure, there is a singular point (inflection point) in the vicinity of the carriage position 800 mm from the reference side, but the landing position deviation is almost biased in the plus direction outside the vicinity of 800 mm. In this example, the maximum deviation amount is about 30 μm near the carriage position of 600 mm.

  On the other hand, FIG. 14 shows the landing positions of the reference color and the adjustment color after the landing adjustment is applied with an adjustment value different from that of FIG. 13 so that the landing position deviation is minimized in the limited print region. Show the relationship. Here, the printing range is set to a range of 600 mm. As shown in the figure, since the carriage behavior is relatively gentle from the printing start position to the vicinity of the center, recalculate the adjustment value separately from the case of the entire scanning area when the printing area is about half. This makes it possible to reduce the amount of landing deviation. When the adjustment value is reset in this example, the maximum deviation amount is about 15 μm near the carriage position 150 mm. When determining the print area, it may be determined whether the recording medium size is used, or even if the recording medium size is the same, the print width of the image may be used for more accurate determination. .

  In the above description, the shift amount in the transport direction is obtained from the pattern. However, since the shift in the transport direction is mainly caused by the change in the posture of the carriage, the recording position can be detected by directly detecting the change in the carriage rail. You may make it estimate deviation | shift amount.

DESCRIPTION OF SYMBOLS 1 Recording head 3 Recording medium 4 Carriage 30 Optical sensor 400 Controller 401 CPU
403 RAM
405 ROM

  A scanning direction that includes a transport unit that transports a recording medium in a predetermined direction, and has a plurality of nozzle arrays for ejecting ink arranged in a direction that intersects the predetermined direction. An ink jet recording apparatus that performs recording by ejecting ink onto a recording medium while scanning the image, and information regarding a displacement amount of the recording position in the predetermined direction between two nozzle arrays of the plurality of nozzle arrays. An acquisition unit that acquires each of a plurality of combinations in which the combination of two nozzle rows is different from each other, and the plurality of the plurality of combinations in the predetermined direction based on information about the shift amount for each of the plurality of combinations acquired by the acquisition unit. Adjustment amount determining means for determining an adjustment amount for adjusting the recording position between the nozzle rows of The adjustment amount determining means determines a first nozzle row in which the deviation amount from the plurality of nozzle rows to a predetermined reference nozzle row exceeds a predetermined threshold, and the plurality of nozzle rows based on the reference nozzle row The adjustment amount for adjusting the recording position of the first nozzle row is determined so as to reduce the amount of deviation between the reference nozzle row and the first nozzle row. The second nozzle in which the deviation amount between the first nozzle row when the adjustment amount of the first nozzle row is reflected and the reference nozzle row of the plurality of nozzle rows is equal to or less than the predetermined threshold value When the amount of deviation between the columns is larger than a predetermined reference value, the adjustment amount for adjusting the recording position of the second nozzle row is determined so as to reduce the amount of deviation. Inkjet recording apparatus.

Claims (5)

An inkjet recording apparatus that scans a recording head in which a plurality of nozzle arrays for ejecting ink are arranged in a predetermined direction in a scanning direction, and performs recording by transporting a recording medium in a direction intersecting the predetermined direction,
Obtaining means for obtaining a displacement amount of the recording position for each of the plurality of nozzle rows in the intersecting direction at a plurality of positions in the predetermined direction;
A determination unit that compares a displacement amount of the recording position for each acquired nozzle row and a threshold value, and determines a nozzle row that exceeds the threshold value;
Setting means for preferentially setting an adjustment value for adjusting a printing position for a nozzle row exceeding the threshold;
An ink jet recording apparatus comprising:   The acquisition unit includes a forming unit that forms a pattern at a plurality of positions in the predetermined direction using the plurality of nozzle rows, and an optical detection unit that detects optical information of the plurality of patterns. The ink jet recording apparatus according to claim 1.   3. The setting unit according to claim 1, wherein the setting unit sets an adjustment value that minimizes the shift amount at a plurality of positions in the predetermined direction for all combinations of nozzle rows exceeding a threshold value. Inkjet recording device.   The inkjet recording apparatus according to claim 1, wherein the setting unit varies the adjustment value according to a recording range of the recording head in the scanning direction. The intersection in an ink jet recording apparatus that performs recording by scanning a recording head in which a plurality of nozzle arrays for ejecting ink are arranged in a predetermined direction in a scanning direction and transporting a recording medium in a direction intersecting the predetermined direction. A method for adjusting the recording position in the direction to
Obtaining a shift amount of the recording position for each of the plurality of nozzle rows in the intersecting direction at a plurality of positions in the predetermined direction;
Comparing the amount of displacement of the recording position for each acquired nozzle row and a threshold, and determining a nozzle row exceeding the threshold;
Preferentially setting an adjustment value for adjusting a printing position for a nozzle row exceeding the threshold; and
A recording position adjusting method comprising:

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