Method, program, and apparatus for acquiring correction values.

Abstract

The ability to accurately obtain the amount of deviation in the rotation direction (θ) of the ejection nozzle of a recording head that ejects ink with low contrast. [Solution] A recording device that records an image on a recording medium while scanning a first recording head having a plurality of first nozzles arranged to eject a first ink and a second recording head having a plurality of second nozzles arranged to eject a second ink with a lower density than the first ink, provides a method for obtaining a correction value to correct the rotational ejection position misalignment of the second recording head, comprising: a recording step of scanning the first recording head and the second recording head and recording a predetermined correction pattern on the recording medium; a step of obtaining the amount of rotational ejection position misalignment of the second recording head by detecting the correction pattern while scanning an optical sensor; and a step of deriving a correction value to correct the rotational ejection position misalignment of the second recording head based on the amount of misalignment, thereby enabling accurate acquisition of the rotational misalignment of the ejection nozzles.

Description

Technical Field

[0001] This disclosure relates to a technique for correcting the deviation amount of the rotation direction (θ) of the nozzle array of a recording head.

Background Art

[0002] Conventionally, it is known to adjust the position of the nozzle array of a recording head in the rotation direction (θ). For example, Patent Document 1 describes a technique for obtaining the amount of θ deviation of a recording head based on the density difference due to the difference in the area factor of different patterns ejected and recorded from the nozzle array.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a recording head that ejects ink with a small contrast, such as transparent ink or thin ink, it may not be possible to obtain the amount of θ deviation of the recording head. For example, in the technique disclosed in Patent Document 1, in the case of ink with a small contrast, it may not be possible to discriminate the density difference due to the difference in the area factor of each pattern, and thus the amount of θ deviation of the recording head may not be obtained.

Means for Solving the Problems

[0005] A recording method according to one aspect of the present disclosure is a recording device that records an image on a recording medium while scanning a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and a second recording head having a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, in a second direction intersecting the first direction, a method for obtaining a correction value for correcting the displacement of the ejection position of the second recording head in the rotational direction with respect to the first direction, comprising: a recording step of recording a predetermined correction pattern on the recording medium by scanning the first recording head and the second recording head in the second direction; an acquisition step of obtaining the amount of displacement of the ejection position of the second recording head in the rotational direction by detecting the correction pattern while scanning an optical sensor in the second direction; and based on the amount of displacement, the second recording head The recording step includes a derivation step of deriving a correction value for correcting the discharge position deviation in the rotational direction, wherein the recording step includes recording an origin pattern using the first nozzle row, recording a first adjustment pattern using an adjacent first nozzle group from among the plurality of second nozzles included in the second nozzle row, and recording a second adjustment pattern using an adjacent second nozzle group different from the first nozzle group from among the plurality of second nozzles included in the second nozzle row, and the acquisition step is characterized in that, based on the detection result of the correction pattern, the amount of displacement of the discharge position of the second recording head in the rotational direction is obtained from the difference between the distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the first adjustment pattern, and the distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the second adjustment pattern. [Effects of the Invention]

[0006] According to this disclosure, the amount of deviation in the rotational direction (θ) of the ejection nozzle of a recording head that ejects ink with low contrast can be accurately obtained. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a schematic configuration of the recording device according to this embodiment. [Figure 2] This figure shows an example of the schematic configuration of the main parts of the recording device shown in Figure 1. [Figure 3] This figure shows an example of a schematic configuration of the optical sensor shown in Figure 2. [Figure 4] This figure shows an example of the ink ejection port surface of the recording head shown in Figure 2. [Figure 5] This is a block diagram illustrating the control system of the recording device. [Figure 6] This is a diagram showing ideal vertical lines. [Figure 7] This figure shows an example of what happens when the nozzle row in Figure 4 is tilted. [Figure 8] This figure shows the result of recording a vertical ruled line pattern extending in the Y direction, with θ correction applied to the nozzle row that ejects color ink, but without θ correction applied to the nozzle row that ejects the reaction solution. [Figure 9] This diagram shows the pattern when the recording head is not tilted. [Figure 10] This figure shows examples of ink droplet dot arrangements when recording each pattern in Figure 9. [Figure 11] As an example of a water-resistant recording medium, this figure shows the optical characteristics when the origin pattern and adjustment pattern shown in Figure 9 are recorded on gloss polyvinyl chloride film. [Figure 12] Figure 7 shows the origin pattern and adjustment pattern on the recording medium as recorded by the recording head. [Figure 13] This is a flowchart illustrating the process of obtaining the correction amount for the recording head according to the first embodiment. [Figure 14] This figure shows the origin pattern and adjustment pattern on the recording medium according to the recording head of the second embodiment. [Figure 15] This is a flowchart illustrating the process of obtaining the correction amount for the recording head according to the second embodiment. [Figure 16]FIG. is a diagram showing an origin pattern and an adjustment pattern of a reaction liquid on a recording medium by a recording head according to a third embodiment. [Figure 17] FIG. is a flowchart for explaining a process of obtaining a correction amount of a recording head according to a third embodiment. [Figure 18] FIG. is a diagram showing an origin pattern, an adjustment pattern, and a reference pattern on a recording medium by a recording head according to a fourth embodiment. [Figure 19] FIG. is a flowchart for explaining a process of obtaining a correction amount of a recording head according to a fourth embodiment. [Figure 20] FIG. is a diagram showing a use case with a low color saturation of a pattern. [Figure 21] FIG. is a diagram showing optical characteristics of the pattern in FIG. 20. [Figure 22] FIG. is a diagram showing an origin pattern and an adjustment pattern on a recording medium when a recording head that discharges light cyan ink to be corrected is mounted in an inclined manner.

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the disclosed matter, and not all combinations of features described in the following embodiments are essential for the solution means of the present disclosure. The same reference numerals are assigned to the same components.

[0009] In the following description, a recording apparatus using an inkjet recording method will be described as an example. The recording apparatus may be, for example, a single function printer having only a recording function, or a multi-function printer having a plurality of functions such as a recording function, a fax function, and a scanner function. Alternatively, it may be a manufacturing apparatus for manufacturing a color filter, an electronic device, an optical device, a micro-structure, etc. by a predetermined recording method.

[0010] In addition, "recording" not only refers to the case of forming significant information such as characters and figures, but also includes both significant and insignificant information. Furthermore, regardless of whether it is manifested so that it can be perceived visually by humans, it widely refers to forming images, patterns, structures, etc. on a recording medium, or "recording" also includes the case of processing the medium. The "recording medium" includes not only paper used in general recording devices, but also those that can receive ink, such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, etc. Furthermore, "ink" refers to a liquid used for "recording" regardless of whether it contains coloring materials.

[0011] (First Embodiment) First, a recording apparatus according to the first embodiment will be described while referring to FIGS. 1 to 8. The recording apparatus according to the present embodiment is a so-called serial scan type inkjet recording apparatus that discharges ink from a recording head by an inkjet method while moving the recording head in a main scanning direction intersecting the conveyance direction with respect to a conveyed recording medium P.

[0012] (Configuration of the Recording Apparatus) FIG. 1 is a diagram showing an example of a schematic configuration of a recording apparatus 10 according to the present embodiment. FIG. 2 is a diagram showing an example of a schematic configuration of a main part of the recording apparatus 10 in FIG. 1. FIG. 3 is a diagram showing an example of a schematic configuration of an optical sensor 200 in FIG. 2. FIG. 3(a) is a diagram showing an example of an optical path of the optical sensor 200. FIG. 3(b) is a diagram showing an example of a detection spot of the optical sensor 200. FIG. 4 is a diagram showing an example of an ink ejection port surface 34 of the recording head 24 in FIG. 2. FIG. 5 is a block diagram for explaining a control system of the recording apparatus 10.

[0013] (Overall Configuration) As shown in Figure 1, the recording device 10 comprises a platen 12, a recording unit 14, a guide shaft 20, a spool 21, and a linear encoder 30. As shown in Figure 2, the recording device 10 accommodates a roll of paper 27. The platen 12 supports the recording medium P, which is transported from the roll of paper 27 by a transport unit. The transport unit comprises a transport roller 23 as shown in Figure 2 and a motor in the motor group 118 as shown in Figure 5 that corresponds to the transport of the recording medium P. The transport roller 23 is driven by this motor via a gear. The recording medium P is sheet-shaped and, as shown in Figure 2, is housed in the recording device 10 in a roll of paper 27. The recording medium P is unwound from the roll of paper 27 and fed. For example, the transport roller 23 transports the recording medium P, which has been unwound from the roll of paper 27 and fed, to the platen 12. The recording unit 14 records on the recording medium P supported by the platen 12. As shown in Figure 2, the recording device 10 winds the recording medium P after recording onto the spool 21. The transport mechanism of the transport unit is not limited to these and can be configured using various known technologies. For example, the transport mechanism of the transport unit may include a path that inverts the front and back sides of the recording medium P so that ink can be ejected onto the back side of the recording medium P. Also, as shown in Figure 2, the recording device 10 is equipped with a heating unit 16. The heating unit 16 heats the recording surface Pf of the recording medium P after recording by the recording unit 14. A guide unit 19 is provided below the heating unit 16 and downstream of the platen 12 in the +Y direction. The shape of the guide unit 19 is configured to be curved toward the spool 21 with a constant curvature. With this configuration, the recording medium P can be transported to the spool 21 along the guide unit 19. As will be described in detail later, the overall operation of the recording device 10 is controlled by the control unit 100 (described later) shown in Figure 5.

[0014] (Record Section 14) As shown in Figure 2, the recording unit 14 comprises a carriage 22 and a recording head 24. The carriage 22 is movably mounted on the guide shaft 20 in Figure 1. The guide shaft 20 is provided along the X direction intersecting the Y direction in which the recording medium P is transported. In this embodiment, the X direction intersecting the Y direction is perpendicular to the Y direction. The carriage 22 is configured to reciprocate along the guide shaft 20 in the +X and -X directions. The recording head 24 has an ejection port surface 34, as shown in Figures 2 and 4. As shown in Figure 2, the recording head 24 is mounted on the carriage 22 such that the ejection port surface 34 is positioned opposite the platen 12. Also, as shown in Figure 4, the ejection port surface 34 has a plurality of nozzles 32. Each nozzle 32 ejects ink. With this configuration of the recording device 10, the recording head 24 can eject ink while reciprocating in the ±X directions. Specifically, the recording head 24 comprises a recording head 24a and a recording head 24b, as shown in Figure 4. Each of the recording heads 24a and 24b is mounted on the carriage 22 parallel to the Y direction, with a constant gap between them along the X direction. Specifically, the direction of alignment of the nozzles 32 of the recording head 24a and the direction of alignment of the nozzles 32 of the recording head 24b are parallel. Therefore, the recording heads 24a and 24b maintain a parallel relationship with each other. The specific movement mechanism of the carriage 22 is not particularly limited. For example, as the movement mechanism of the carriage 22, various known technologies such as carriage belts and lead screws can be used as a mechanism to transmit the driving force from the motor corresponding to the movement of the carriage 22 in the motor group 118 in Figure 5.

[0015] (Linear encoder 30) The linear encoder 30 is mounted along the guide shaft 20. The position of the recording head 24 is controlled based on the position signal detected from the linear encoder 30. The recording head 24 is configured to dispense ink and a reaction solution. The ink contains a colorant. The reaction solution reacts with the ink to promote thickening and solidification of the ink, thereby changing its concentration on the recording medium P. In this embodiment, the ink containing the colorant is appropriately referred to as ink or color ink. In this embodiment, it is assumed that the color inks dispensed from the recording head 24 are black ink (K ink), cyan ink (C ink), magenta ink (M ink), and yellow ink (Y ink). Each of these four inks is a pigment ink containing a colorant that represents the corresponding color. The colors and number of inks dispensed are not limited to the four colors described above. For example, spot color inks may be dispensed. Spot color inks are, for example, inks corresponding to special colors used in national flags, etc. Furthermore, in a broader sense, the reaction solution can also be treated as a type of ink.

[0016] (Operation of recording head 24) The recording device 10 moves the recording head 24 at a speed of, for example, 45 inches / sec and performs recording at a resolution of 1200 dpi (1 / 1200 inch). First, when recording starts, the recording device 10 moves the recording head 24 to the recording start position and transports the recording medium P to a position where it can be recorded by the recording head 24 using the transport unit. Next, the recording device 10 performs a recording operation in which ink is ejected while moving (scanning) the recording head 24 in the +X direction (or -X direction) based on the recording data. When this recording operation is completed, the recording device 10 performs a transport operation in which the recording medium P is transported by a predetermined amount using the transport unit. After that, the recording device 10 performs a recording operation in which ink is ejected while moving the recording head 24 in the -X direction (or +X direction). In this way, the recording device 10 repeatedly performs the recording operation and the transport operation alternately. According to this operation, the recording data is recorded on the recording medium P. In this embodiment, the recording device 10 is assumed to perform multipath recording, for example, by having the recording head 24 scan a unit area on the recording medium P multiple times.

[0017] (Heating section 16) The heating unit 16 in Figure 2 irradiates heat onto the recording surface Pf of the recording medium P, which has been recorded by ink (and reaction solution) ejected from the recording head 24 of the recording unit 14. This operation heats the recording surface Pf and the ink ejected onto the recording surface Pf, fixing the ink to the recording surface Pf. Along the Z direction, the area above the heating unit 16 is covered by a cover 17. The cover 17 serves two functions: efficiently reflecting the heat from the heating unit 16 onto the recording medium P, and protecting the heating unit 16. The heating unit 16 can be composed of various heaters, such as sheath heaters and halogen heaters. The heating unit 16 may be configured to heat using hot air, not just non-contact heat conduction heaters. Note that the heating unit 16 is not limited to a configuration that heats the recording surface Pf of the recording medium P. For example, the heating unit 16 may be provided downstream of the platen 12 in the +Y direction and vertically below the guide unit 19. In this configuration, the heating unit 16 is located vertically below (upstream in the +Z direction) the guide unit 19 that guides the recording medium P after recording. Therefore, with the heating unit 16 in this arrangement, the recording medium P can be heated from the back surface Pb. The heating temperature at which the heating unit 16 heats the recording medium P is set considering factors such as ink fixation and the productivity of the recording medium P. Furthermore, multiple heating units 16 may be provided.

[0018] As will be explained in more detail later, the ink used in the recording device 10 contains pigment, resin fine particles, and a water-soluble organic solvent. Therefore, the recording device 10 can fix the pigment to the recording medium by heating the resin fine particles contained in the ink in the heating unit 16 to melt the resin fine particles and then evaporating the water-soluble organic solvent in the ink.

[0019] Inks containing resin microparticles have the property of improving abrasion resistance (fixability). For this reason, it is desirable that the heating temperature of the ink be above the minimum film-forming temperature of the resin microparticles. In addition, it is necessary to evaporate most of the liquid components such as water-soluble organic solvents in the ink during heating. Accordingly, the heating unit 16 is configured to have a temperature distribution along the transport direction of the recording medium that ensures sufficient heating time to supply the energy necessary for the evaporation of most of the liquid components.

[0020] Furthermore, the recording device 10 may include a recovery unit (not shown) for maintaining and restoring the good ejection state of ink and reaction liquid from the nozzles 32 of the recording head 24. This recovery unit is provided adjacent to the platen 12 near the end of the recording head 24 in the scanning direction (movement direction). Known configurations can be used for the recovery unit, such as a wiping unit for wiping the ejection port surface 34, or a cap for protecting the ejection port surface 34.

[0021] (Overview of Optical Sensor 200) Next, the configuration of the optical sensor 200 will be described using Figure 3. The optical sensor 200 is positioned, for example, on the upstream side of the carriage 22 in the +X direction. The optical sensor 200 detects the optical characteristics of the recording medium P. The optical sensor 200 is composed, for example, of a reflective optical sensor. Based on the detection result of the optical sensor, the recording device 10 can detect the OD (Optical Density) value as the reflective optical characteristics on the recording medium P. Note that the installation position of the optical sensor 200 is not limited to this. That is, it may be provided on the downstream side of the carriage 22 in the +X direction, or on the downstream side in the +Y direction. Alternatively, it may be provided independently of the carriage 22 and configured to be movable in the X direction, or it may be configured to be arranged along the X direction across the width of the recording medium P. Furthermore, detection devices other than the optical sensor 200 described below may be used.

[0022] (Arrangement configuration of optical sensor 200) Specifically, the optical sensor 200 is fixedly mounted on the carriage 22 such that, in the Y direction, the measurement area is located downstream in the +Y direction from the nozzle row 33 of the recording head 24. The nozzle row 33 will be described later with reference to Figure 4, but the lower surface 200a of the optical sensor 200 coincides with the discharge port surface 34 in the Z direction, or is located downstream in the +Z direction from the discharge port surface 34.

[0023] (Functions of optical sensor 200) The optical sensor 200 comprises a light-emitting unit 302 and a light-receiving unit 304. The light-emitting unit 302 is composed of visible LEDs such as red, green, and blue. The light-receiving unit 304 is composed of a photodiode. The light-emitting unit 302 and the light-receiving unit 304 are provided on the lower surface 200a of the optical sensor 200. The light-emitting unit 302 irradiates light toward the recording medium P. On the other hand, the light-receiving unit 304 receives reflected light reflected from the recording medium P or the surrounding area of ​​the recording medium P. Therefore, in the optical sensor 200, the light 306 irradiated from the light-emitting unit 302 is diffusely reflected by the recording medium P, and this reflected light 308 is received by the light-receiving unit 304. The diameter of the detection spot 310, where the light 306 irradiated from the light-emitting unit 302 is diffusely reflected by the recording medium P, is, for example, approximately 3 mm in diameter. The light receiving unit 304 transmits the detection signal (analog signal) of the received reflected light 308 to the control circuit on the electrical board of the recording device 10 via a flexible cable (not shown), and converts it into a digital signal by an A / D converter in the control circuit. As will be described later, when detecting the optical characteristics of the adjustment pattern, the transport of the recording medium P in the Y direction and the movement of the carriage 22 to which the optical sensor 200 is attached in the X direction are performed alternately. This operation is synchronized with the timing based on the position signal obtained by the linear encoder 30, and the optical sensor 200 detects the density of the recording result (also called the recorded material) recorded on the recording medium P as optical reflectance. In this way, the recording device 10 irradiates each pattern of the adjustment pattern on the recording medium P with light and detects the reflection intensity that reflects the density of the pattern. Therefore, when the recording medium P is white, the reflection intensity is strong. On the other hand, the reflection intensity becomes weaker the denser the pattern.

[0024] (Recording head configuration) Next, the configuration of the recording head 24 will be described using Figure 4. Figure 4 is a view of the ejection port surface 34 of Figure 2 from the +Z direction. The rotation direction θ of the nozzle row 33 indicates the inclination of the nozzle row 33 with respect to the sub-scanning direction. That is, the rotation direction θ of the nozzle row 33 indicates the inclination of the nozzle row 33 with respect to the +Y direction. Each of the recording heads 24a and 24b is individually mounted on the carriage 22. A nozzle row 33 is formed on the ejection port surface 34 of the recording head 24. The nozzle row 33 consists of multiple nozzles 32 that eject corresponding liquids, arranged along the Y direction. Specifically, on the ejection port surface 34a of the recording head 24a, a nozzle row 33K for ejecting K ink, a nozzle row 33C for ejecting C ink, a nozzle row 33M for ejecting M ink, and a nozzle row 33Y for ejecting Y ink are formed in order in the +X direction. Meanwhile, a series of nozzles 33RCT for discharging the reaction solution RCT is formed on the discharge port surface 34b of the recording head 24b.

[0025] As explained above, the RCT reaction solution reacts with the color ink to promote its solidification and thickening. Specifically, the RCT reaction solution does not contain colorants, but it contains reactive components that react with the colorants in the color ink. Due to this composition, the RCT reaction solution solidifies and thickens the color ink upon contact. This action suppresses the bleeding of the color ink on the recording medium P.

[0026] In this embodiment, it is assumed that each nozzle row 33 has 1280 nozzles 32 arranged in the Y direction at a density of 1200 dpi. It is also assumed that the amount of liquid (color ink and reaction solution) discharged at one time from a single nozzle 32 is, for example, about 4.5 pl. Furthermore, it is assumed that each nozzle row 33 is connected to a tank (not shown) for storing the corresponding liquid, and that the ink and reaction solution are supplied from this tank. The tank may be integrally configured with the recording head 24, or it may be detachable from the carriage 22.

[0027] (Color ink and reaction solution) Next, the color ink and reaction solution used in the recording device 10 will be described. In this embodiment, the recording device 10 can use pigment ink containing pigment, or water-soluble resin fine particle ink that does not contain pigment or contains a small amount of pigment. These pigment inks and water-soluble resin fine particle inks contain a water-soluble organic solvent. Various surfactants, defoamers, preservatives, fungicides, etc. can be added to the color ink as needed to give it desired properties.

[0028] (Color ink) The color ink contains water-soluble resin microparticles to adhere the colorant to the recording medium P and improve the scratch resistance (fixability) of the recorded image. The resin microparticles are dissolved by heat, and a heater (heating unit 16, etc.) is used to form a film of the resin microparticles and dry the solvent contained in the ink. In this embodiment, the resin microparticles are polymer microparticles that exist in a dispersed state in water. The polymer microparticles that exist in a dispersed state in water may also be in the form of resin microparticles obtained by homopolymerizing monomers having dissociable groups, or copolymerizing multiple types, so-called self-dispersing resin microparticle dispersions. The color ink contains a surfactant. As the surfactant, a penetrating agent is used to improve the penetration of the color ink into the inkjet-specific recording medium P. In this embodiment, the surface tension of each color ink is 30 dyn / cm or less, and the difference in surface tension between each color ink is adjusted to be within 2 dyn / cm. Specifically, the surface tension of each color ink is set to approximately 28 to 30 dyn / cm. Furthermore, the following is preferable for the color ink from the viewpoint of preventing the elution of impurities from components that come into contact with the ink inside the housing of the recording device 10 or the recording head 24, the deterioration of the materials constituting the components, and the decrease in the solubility of the pigment dispersion resin in the ink. Specifically, its pH is preferably 7.0 or higher and 10.0 or lower. The color ink used in this embodiment uses anionic colorants. For this reason, the pH of each color ink is stable on the alkaline side, and the pH of each color ink is 8.5 to 9.5.

[0029] (Reaction solution) The reaction solution contains a reactive component that reacts with the pigment contained in each color ink, causing the pigment to aggregate or gel. Alternatively, the reaction solution contains a reactive component that reacts with a resin or the like, causing the pigment to become insoluble. A reactive component is, for example, a component that, when mixed with an ink having a target component that is stably dispersed in an aqueous medium by the action of ionic groups, can disrupt the dispersion stability in the ink. As a reactive component, an organic acid such as glutaric acid can be used. The content of the organic acid in the reaction solution is preferably 3.0% by mass or more and 90.0% by mass or less, and more preferably 5.0% by mass or more and 70.0% by mass or less, based on the total mass of the composition contained in the reaction solution. In addition, a surfactant is added to the reaction solution in the same manner as the color ink.

[0030] (Control configuration of the recording device) Next, the configuration of the control system of the recording device 10 will be described using Figure 5. In addition to the above description, the recording device 10 further includes a control unit 100, an interface circuit 112, an operation panel 124, a motor driver 116, a motor group 118, a head driver 120, and a drive circuit 122 as part of its control system. The recording device 10 can also be connected to an external host device 114. The control unit 100, which controls the entire recording device 10, includes a central processing unit (CPU) 102, a ROM 104, a RAM 106, and a memory 108. The CPU 102 controls the operation of each component in the recording device 10 and executes image data processing programs based on various programs. The ROM 104 functions as a memory that stores the operation control of each component and image data processing programs executed by the CPU 102. The RAM 106 stores various data used to control the recording device 10. The memory 108 stores various data such as mask patterns and adjustment patterns, which will be described later. The control unit 100 also includes an input / output port 110. The control unit 100 is connected to various drivers, drive circuits, etc., via the input / output port 110.

[0031] The control unit 100 is connected to the interface circuit 112 via the input / output port 110. The control unit 100 is connected to the host device 114 via the interface circuit 112. The control unit 100 is also connected to the operation panel 124 via the input / output port 110. The operation panel 124 accepts user input and displays a screen corresponding to the user's input. The operation panel 124 is composed of, for example, a liquid crystal display with a touch panel. The user can input image data to the recording device 10 via the host device 114, and can also input various types of information to the recording device 10 via the host device 114 and the operation panel 124. The control unit 100 is also connected to the motor driver 116 via the input / output port 110. The control unit 100 controls the driving of the motor group 118 via the motor driver 116. In the example shown in Figure 5, various motors in the recording device 10, such as the motor that moves the carriage 22 and the motor that drives the transport unit that transports the recording medium P, are collectively shown as the motor group 118.

[0032] Furthermore, the control unit 100 is connected to the head driver 120 via the input / output port 110. The control unit 100 controls the recording head 24 via the head driver 120 to eject ink. The control unit 100 is connected to the drive circuit 122 via the input / output port 110. The control unit 100 controls the drive of the heating unit 16 via the drive circuit 122. In addition, the control unit 100 is connected to the optical sensor 200 via the input / output port 110. The control unit 100 controls the drive of the optical sensor 200 and detects the optical characteristics of the adjustment pattern based on the output from the optical sensor 200. Thus, in this embodiment, the control unit 100 and the optical sensor 200 function as a detection unit capable of detecting the optical characteristics of the recording material recorded on the recording medium P.

[0033] The CPU 102 converts image data input from the host device 114 into recording data and stores it in the RAM 106. Specifically, the CPU 102 acquires image data represented by 256 values ​​(0 to 255) for each of the RGB values. The CPU 102 then performs a color conversion process on the acquired image data to convert it into multi-level data represented by multiple types of inks (K, C, M, Y in this embodiment) used for recording. This color conversion process generates multi-level data represented by 256 values ​​(0 to 255) for each of the K, C, M, and Y inks in a group of pixels consisting of multiple pixels.

[0034] Next, the CPU 102 performs a quantization process for the multi-level data represented by K, C, M, and Y. Specifically, the CPU 102 generates quantized data (binary data) represented by 1-bit binary information (0, 1) that determines whether each pixel ejects or does not eject each of the K, C, M, and Y inks. Various known quantization methods such as error diffusion, dithering, and indexing can be used for this quantization process. Subsequently, the CPU 102 performs a distribution process to distribute the quantized data to multiple scans of the unit area of ​​the recording head 24. This distribution process generates recording data represented by 1-bit binary information (0, 1) that determines whether each pixel ejects or does not eject each of the K, C, M, and Y inks in each of the multiple scans of the unit area of ​​the recording medium P. This distribution process is performed using a mask pattern that corresponds to multiple scans and determines whether each pixel is allowed to eject or not. The generation of such recorded data is not limited to being performed by the control unit 100; it may also be performed by the host device 114, or some processing may be performed by the host device 114 and the remaining processing by the control unit 100.

[0035] (Retrieval process) In the above configuration, the recording device 10 performs a recording process to record data on the recording medium P based on the recorded data. In this recording process, the recording head 24 moves in the X direction via the carriage 22 and ejects ink (reaction liquid) to record in a unit area on the recording medium P. When recording in this manner, basically, a predetermined amount of color ink and reaction liquid are ejected into the same area. This operation ensures that the reaction liquid comes into contact with the color ink at a constant ratio, which suppresses ink bleeding, which is particularly noticeable on non-absorbent recording medium P. Furthermore, the recording medium P on which the color ink and reaction liquid have been ejected is transported and passes through the heating unit 16, where the color ink is heated and dried. This operation allows for recording with improved ink fixation, even if the recording medium P is non-absorbent or poorly absorbent.

[0036] As described above, the recording device 10 requires that the color ink and the reaction solution be ejected in the same area. Therefore, the recording device 10 can acquire the amount of displacement of the reaction solution's ejection position relative to the ejection position of the color ink. In the following explanation, "the amount of displacement of the reaction solution's ejection position relative to the ejection position of the color ink" will also be referred to as "the amount of displacement of the reaction solution's ejection position."

[0037] The acquisition process for obtaining the amount of deviation in the discharge position of the reaction solution is performed, for example, when the user instructs the start of the acquisition process via the host device 114, the operation panel 124, etc. The recording device 10 acquires a correction value for correcting the discharge timing of the reaction solution based on the amount of deviation in the discharge position of the reaction solution acquired in this acquisition process. Then, during the recording process, the reaction solution is discharged while correcting the discharge timing based on the acquired correction value.

[0038] Furthermore, the recording device 10 is configured to acquire the amount of displacement of the ejection position in the rotational direction of the recording head 24. Figure 4 shows a state in which the recording head 24 is ideally mounted on the recording device 10 and ink dots can be ideally positioned on the recording medium P. Figure 6 shows an image of the recording medium when vertical lines are recorded in this ideal state. Figure 6 shows an ideal vertical line. With an ideal vertical line like the one shown in Figure 6, it is possible to obtain the line intended by the user. However, since the amount of displacement varies depending on the recording head 24 and the recording device 10, it is not realistic from a cost and technical standpoint to position the nozzle 32 in the ideal position relative to the recording medium P using only hardware. In addition, with the recent trend towards higher image quality and smaller ink dot droplets, the demand for ink dot landing accuracy on the recording medium P has increased.

[0039] Given the above circumstances, the recording heads 24a and 24b may be mounted in the state shown in Figure 7. Figure 7 shows an example of the case where the nozzle row 33 in Figure 4 is tilted. With the recording heads 24a and 24b mounted in the state shown in Figure 7, rotational direction correction (hereinafter referred to as θ correction) of the recording head 24a that ejects color ink can be handled by known techniques, but θ correction of the recording head 24b that ejects basically colorless reaction liquid is difficult. Figure 8 shows the case where a vertical ruled line pattern extending in the Y direction is recorded by nozzle row 33K and nozzle row 33RCT with θ correction performed on nozzle row 33K but not on nozzle row 33RCT. As shown in Figure 8, even if θ correction is performed on the K ink, if θ correction is not performed on the reaction liquid, the K ink and the reaction liquid will not be recorded in the same area. As a result, bleeding may occur in the ruled lines recorded with K ink, and image degradation may occur. Therefore, θ correction is also necessary for the recording head 24b that ejects the reaction liquid.

[0040] The acquisition process for obtaining the θ correction amount of the recording head 24b, which is performed by the recording device 10, and the patterns adjusted during said acquisition process will be described in detail below.

[0041] (Adjustment pattern) First, we will explain the adjustment patterns used in the acquisition process. Note that the adjustment patterns described below are just examples of those to which this embodiment can be applied, and different adjustment patterns can be set as appropriate in consideration of other factors.

[0042] (If the recording head 24b is not tilted) Figure 9 shows the pattern when there is no tilt of the recording heads 24a and 24b. In Figure 9, an acquisition process is performed to acquire the amount of deviation of the reaction liquid discharge position using the optical sensor 200. It is assumed that the following patterns are recorded during this acquisition process. For example, pattern 91 shows the origin pattern. Patterns 92 and 93 each show adjustment patterns. Pattern 92 consists of pattern 921, pattern 922, and pattern 923. Pattern 93 consists of pattern 931, pattern 932, and pattern 933. Specifically, as explained using Figure 4, each of the recording heads 24a and 24b has multiple nozzles arranged on it. In Figure 9, among the multiple nozzles arranged on each of the recording heads 24a and 24b, those located on the downstream end side of the recording heads 24a and 24b are referred to as the nozzle group 33 down-end. That is, the nozzle group 33down-end of recording head 24a is located on the downstream end side of recording head 24a. The nozzle group 33down-end of recording head 24b is located on the downstream end side of recording head 24b. Furthermore, among the multiple nozzles arranged on each of the recording heads 24a and 24b, those located on the upstream end side of recording heads 24a and 24b are referred to as the nozzle group 33up-end. That is, the nozzle group 33up-end of recording head 24a is located on the upstream end side of recording head 24a. The nozzle group 33up-end of recording head 24b is located on the upstream end side of recording head 24b. Therefore, the nozzle group 33down-end is a collection of some of the multiple nozzles. Also, the nozzle group 33up-end is a collection of other parts of the multiple nozzles. Here, a nozzle collection is a collection of at least one nozzle 32 (see Figure 4) among the multiple nozzles 32.

[0043] Patterns 91 and 92 are recorded on the recording medium P by the nozzle group 33down-end of recording head 24a and the nozzle group 33down-end of recording head 24b. Pattern 93 is recorded on the recording medium P by the nozzle group 33up-end of recording head 24a and the nozzle group 33up-end of recording head 24b. Here, pattern 91 uses at least one color ink and a reaction solution. It is preferable to use K ink, which has high sensor detection accuracy, but other color inks may also be used. Also, if the bleeding of the color ink is small, the reaction solution may not be used for pattern 91. On the other hand, each of pattern 92 and pattern 93 uses at least one color ink and a reaction solution. For example, only K ink is used as the color ink. Furthermore, patterns 921 and 923, which have a smaller amount of reaction solution applied compared to pattern 922, and pattern 922, which has a larger amount of reaction solution applied compared to patterns 921 and 923, are arranged alternately in the X direction.

[0044] (Ink droplet dot arrangement) Figure 10 shows examples of ink droplet dot arrangements when recording each pattern shown in Figure 9. In Figure 10, a grid pattern with 8x8 small regions is used to indicate whether or not ink droplets are dropped. Each small region represents the smallest unit (1 pixel region) on the recording medium P, where dot recording or non-recording can be set. In one example in Figure 10, the black regions in the grid pattern indicate small regions where ink droplets are dropped, and the white regions indicate small regions where ink droplets are not dropped. Figure 10(a) has 64 black regions out of 8x8 small regions. In other words, Figure 10(a) shows a dot arrangement where ink droplets are dropped in 64 out of 64 small regions. Figure 10(b) has 22 black regions out of 8x8 small regions. In other words, Figure 10(b) shows a dot arrangement where ink droplets are dropped in 22 out of 64 small regions. Figure 10(c) has 48 black regions out of 8x8 small regions. In other words, Figure 10(c) shows a dot arrangement in which ink droplets are dropped into 48 out of 64 sub-regions. Figure 10(d) has 13 black regions out of an 8x8 sub-region. In other words, Figure 10(d) shows a dot arrangement in which ink droplets are dropped into 13 out of 64 sub-regions.

[0045] Pattern 91 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(a) and recorded with the reaction solution using the dot arrangement shown in Figure 10(b). Pattern 921 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(c) and recorded with the reaction solution using the dot arrangement shown in Figure 10(d). Pattern 922 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(c) and recorded with the reaction solution using the dot arrangement shown in Figure 10(a). Pattern 923 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(c) and recorded with the reaction solution using the dot arrangement shown in Figure 10(d). In other words, the difference between patterns 921 and 923 and pattern 922 is the dot arrangement of the reaction solution. The dot arrangement of pattern 922 has a higher recording density of dots in the reaction solution compared to the dot arrangements of patterns 921 and 923. Pattern 931 in Figure 9 is recorded in the same way as pattern 921 in Figure 9, so its explanation is omitted. Pattern 932 in Figure 9 is recorded in the same way as pattern 922 in Figure 9, so its explanation is omitted. Pattern 933 in Figure 9 is recorded in the same way as pattern 923 in Figure 9, so its explanation is omitted. In this embodiment, the dot arrangement shown in Figure 10 is used, but a different dot arrangement may be used depending on the recording environment.

[0046] (Water-resistant recording medium) Figure 11 shows the optical characteristics when the origin pattern (pattern 91) and adjustment pattern (pattern 92) from Figure 9 are recorded on a gloss polyvinyl chloride film, as an example of a recording medium that is resistant to wetting. The gloss polyvinyl chloride film has low absorbency and ink droplets do not spread easily. Pattern 111 is a pattern in which pattern 91 and pattern 92 are recorded on the recording medium P in the same area in the Y direction with the same scan. In Figure 11, the non-ejection area S1 indicates an area where ink has not been ejected. Also in Figure 11, ejection areas S2, S3, and S4 indicate areas where ink has been ejected. As shown in Figure 11, the difference in reflection intensity between the non-ejection area S1 and the ejection areas S2, S3, and S4 allows the boundaries of ejection areas S2, S3, and S4 to be detected by the optical sensor 200, which moves in the X direction with the carriage. Therefore, the X-direction positions of ejection areas S2, S3, and S4 can be determined. Furthermore, by recording the adjustment pattern (pattern 92), different amounts of reaction solution are recorded for each of the discharge areas S3 and S4. As shown in Figure 9, in the adjustment pattern (pattern 92), patterns 921 and 922 are adjacent, and patterns 922 and 923 are adjacent, so discharge areas S3 and S4 are adjacent.

[0047] Here, with respect to the ink, patterns 921, 922, and 923 are all recorded at the same recording density according to the dot arrangement shown in Figure 10(c). In contrast, with respect to the reaction liquid, patterns 921 and 923 are recorded according to the dot arrangement shown in Figure 10(d), while pattern 922 is recorded according to the dot arrangement shown in Figure 10(a), which has a higher recording density than the others. In a recording medium that is difficult to wet, the reaction liquid acts to increase the wettability of the ink and increase the area factor. Here, the area factor is the ink coverage rate relative to the pixel area. Therefore, in a recording medium that is difficult to wet, as the amount of reaction liquid discharged increases, the ink coverage rate relative to the pixel area increases, and the area factor tends to increase. Consequently, in the region of pattern 922, where a relatively large amount of reaction liquid is applied, a higher density, i.e., a lower reflectivity, is detected than in the regions of patterns 921 and 923, where a relatively small amount of reaction liquid is applied.

[0048] Thus, according to the adjustment pattern (pattern 92), the area factor of the color ink differs between the ejection area S3 and the ejection area S4, resulting in a difference in reflectance between the two areas, as shown in Figure 11. Therefore, the boundary between the ejection area S3 and the ejection area S4 can be detected by the optical sensor 200 based on the difference in reflectance. Specifically, in the ejection area S3, the amount of reaction solution dispensed to patterns 921 and 923 is relatively small. Therefore, the area factor of the color ink is small, and the reflectance is relatively strong. On the other hand, in the ejection area S4, the amount of reaction solution dispensed to pattern 922 is relatively large. Therefore, the area factor of the color ink is large, and the reflectance is relatively weak. In this way, the difference between the reflectance of the ejection area S3 and the reflectance of the ejection area S4 makes it possible to detect the boundary between the ejection area S3 and the ejection area S4. In the example shown in Figure 11, the median value between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4 is assumed to be the point of change between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4. Therefore, this point of change can be the boundary between discharge region S3 and discharge region S4. Accordingly, it is possible to identify the positions of each discharge region S3 and S4 based on the position of the carriage where the optical sensor 200 detects the reflectance intensity that constitutes the above-mentioned point of change. In the example shown in Figure 11, the median value between the reflectance intensity of discharge region S2, where the origin pattern (pattern 91) is recorded, and the reflectance intensity of the non-discharge region S1 is assumed to be the point of change between the reflectance intensity of discharge region S2 and the non-discharge region S1.

[0049] (Water-sensitive recording media) Figure 11 illustrates the identification of each ejection region when recording on gloss polyvinyl chloride film. As described above, gloss polyvinyl chloride film has low absorbency and ink droplets do not spread easily. On the other hand, synthetic paper has low absorbency and ink droplets spread easily. In other words, synthetic paper is one of the recording media that is easily wetted. Even when recording on synthetic paper, it is possible to identify each ejection region. When the amount of reaction solution applied to synthetic paper is relatively small, the area factor is large and the reflectivity is weak. When the amount of reaction solution applied to synthetic paper is relatively large, the area factor is small and the reflectivity is strong. Therefore, in order to show optical characteristics similar to Figure 11 and to be able to identify the position of each ejection region, it is desirable that patterns 921, 922, and 923 have the following dot arrangement.

[0050] Specifically, pattern 921 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(c) and a pattern recorded with the reaction solution using the dot arrangement shown in Figure 10(a). The difference from the less wettable recording medium is that the dot arrangement density of the reaction solution is higher in the more wettable recording medium. Pattern 922 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(c) and a pattern recorded with the reaction solution using the dot arrangement shown in Figure 10(d). The difference from the less wettable recording medium is that the dot arrangement density of the reaction solution is lower in the more wettable recording medium. Pattern 923 in Figure 9 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(c) and a pattern recorded with the reaction solution using the dot arrangement shown in Figure 10(a). The difference from the less wettable recording medium is that the dot arrangement density of the reaction solution is higher in the more wettable recording medium.

[0051] Furthermore, since pattern 931 in Figure 9 is recorded in the same way as pattern 921 in Figure 9, its explanation is omitted. In other words, the difference between a recording medium that is difficult to wet is that a recording medium that is easy to wet has a higher recording density of reaction solution dots. Since pattern 932 in Figure 9 is recorded in the same way as pattern 922 in Figure 9, its explanation is omitted. In other words, the difference between a recording medium that is difficult to wet is that a recording medium that is easy to wet has a lower recording density of reaction solution dots. Since pattern 933 in Figure 9 is recorded in the same way as pattern 923 in Figure 9, its explanation is omitted. In other words, the difference between a recording medium that is difficult to wet is that a recording medium that is easy to wet has a higher recording density of reaction solution dots.

[0052] Furthermore, a use case may be one in which a water-sensitive recording medium is given the same dot arrangement as a water-resistant recording medium. In this use case, the optical characteristics will differ from those shown in Figure 11. Specifically, the reflectance of the ejection region S3 will be weaker than that of the ejection region S3 in Figure 11. The reflectance of the ejection region S4 will be stronger than that of the ejection region S4 in Figure 11. Therefore, just as with water-resistant recording media, even with water-sensitive recording media, the median value between the reflectance of the ejection region S3 and the reflectance of the ejection region S4 should be set as the point of change between the reflectance of the ejection region S3 and the reflectance of the ejection region S4. Thus, this point of change can be the boundary between the ejection region S3 and the ejection region S4. Consequently, it becomes possible to identify the positions of each ejection region S3 and S4.

[0053] From the above explanation, it is possible to adjust the reflectance intensity by changing the recording density of the dot arrangement in the reaction solution, regardless of whether the recording medium is difficult to wet or easy to wet. By adjusting the reflectance intensity in this way, the boundaries of each pattern can be detected. Furthermore, the positions of adjacent regions can be identified based on the difference in reflectance between adjacent regions. Therefore, it is not necessary to prepare a calculation table in advance for each recording medium P.

[0054] Next, we will specifically describe the operation of identifying the positions of adjacent discharge regions using the method described above, when recording is performed using the recording head 24b, which is filled with a colorless, transparent liquid such as the reaction solution described above. This operation makes it possible to accurately obtain the amount of displacement in the rotation direction (θ) of the nozzle row 33. Details will be explained below.

[0055] (Adjustment method in the first embodiment) In the first embodiment, it is assumed that there is one origin pattern, the ejection position of the color ink is corrected, and the ejection position of the reaction solution is not corrected.

[0056] Figure 12 shows the origin pattern and adjustment pattern on the recording medium P by the recording head 24 of Figure 7. In Figure 12, pattern 91 is the origin pattern. Also in Figure 12, patterns 101 and 222 are adjustment patterns. Recording heads 24a and 24b are mounted offset from each other in the θ rotation direction. However, in Figure 12, it is assumed that the ejection position of the color ink ejected from recording head 24a is corrected. Therefore, although both ends of pattern 101 and pattern 222 are aligned, the dense region of pattern 222 is shifted in the +X direction relative to the dense region of pattern 101. That is, the dense region of the adjustment pattern (pattern 222) is recorded shifted in the +X direction relative to the dense region of the adjustment pattern (pattern 101). Here, the dense region of the adjustment pattern (pattern 222) is the region where the reaction solution is recorded from the nozzle group 33up-end of recording head 24b. The nozzle group 33up-end of the recording head 24b is arranged on the upstream end side of the recording head 24b. On the other hand, the darker areas of the adjustment pattern (pattern 101) are the areas where the reaction solution is recorded from the nozzle group 33down-end of the recording head 24b. The nozzle group 33down-end of the recording head 24b is arranged on the downstream end side of the recording head 24b. Note that in the leftmost area of ​​pattern 222, there is a portion where the reaction solution is not discharged due to the θ rotational displacement of the recording head 24b, so that area is lighter in color compared to other areas.

[0057] Figure 13 is a flowchart illustrating the process of acquiring the θ correction amount of the recording head 24b according to the first embodiment. The series of processes shown in the flowchart of Figure 13 are performed by the CPU 102 expanding the program code stored in the ROM 104 into the RAM 106 and executing it. Alternatively, some or all of the functions of the steps in Figure 13 may be performed by hardware such as an ASIC or electrical circuit. In the description of each process, the symbol S means a step in the flowchart.

[0058] In S1301, the CPU 102 records the patterns. The memory 108 stores, for example, an origin pattern and an adjustment pattern as patterns. In the S1301 process, the origin pattern and the adjustment pattern are recorded as shown in Figure 12. The pattern recording may be performed in a single scan by the carriage 22, or in multiple scans that do not involve transport. Next, in S1302, while scanning the carriage 22, the CPU 102 uses the optical sensor 200 to detect the optical characteristics of the origin pattern and adjustment pattern recorded on the recording medium P. The optical characteristics detected in the S1302 process are, for example, optical characteristics in which the ejection position in the X direction and the reflection intensity are associated, as shown in Figure 11. Such detection is performed for the pattern downstream of the recording head 24 and the pattern upstream of the recording head 24, respectively. Specifically, in the S1302 process, as shown in Figure 11, the reflectance intensity in the origin pattern and the adjustment pattern is detected based on the amount of light received by the optical sensor 200. The reflectance intensity varies depending on the amount of ink and reaction solution dispensed to each ejection area of ​​the object being measured. Specifically, if the object being measured is a recording medium P that is not easily wetted, the higher the recording density of the reaction solution dot arrangement, the larger the area factor and the lower the reflectance intensity. Alternatively, if the object being measured is a recording medium P that is not easily wetted, the lower the recording density of the reaction solution dot arrangement, the smaller the area factor and the higher the reflectance intensity. On the other hand, if the object being measured is a recording medium P that is easily wetted, the lower the recording density of the reaction solution dot arrangement, the larger the area factor and the lower the reflectance intensity. Alternatively, if the recording medium P is easily wetted, the higher the recording density of the reaction solution dot arrangement, the smaller the area factor and the higher the reflectance intensity. Thus, in this embodiment, the control unit 100 equipped with the CPU 102 has the function of controlling the recording head 24 to record the pattern. Furthermore, the control unit 100, which is equipped with a CPU 102, also has the function of controlling an optical sensor 200 that detects the optical characteristics of the recorded pattern.

[0059] Next, in S1303, the CPU 102 performs the following processing based on the optical characteristics of the adjustment pattern detected by the processing in S1302, as shown in Figure 11. Specifically, the CPU 102 obtains the distance A1 between the origin pattern recorded at the nozzle group 33down-end and the adjustment pattern recorded at the nozzle group 33down-end. As described above, the origin pattern and the adjustment pattern are formed from the ink ejected from the nozzle group of the recording head 24a and the reaction liquid ejected from the nozzle group of the recording head 24b. The difference between the origin pattern and the adjustment pattern arises from the difference in the recording density of the ink and the recording density of the reaction liquid, as described above.

[0060] Next, in S1304, the CPU 102 performs the following processing based on the optical characteristics of the adjustment pattern detected by the processing in S1302. That is, the CPU 102 obtains the distance B1 between the origin pattern recorded by the nozzle group 33down-end and the adjustment pattern recorded by the nozzle group 33up-end. Here, the distances obtained by the processing in S1302 and S1303 are distances in the X direction. That is, the distance in the main scanning direction recorded when the recording unit 14 in Figure 1 moves in the main scanning direction along the guide shaft 20. Distance A1 is the distance between pattern 91 and the dense region of pattern 101. Each of pattern 91 and pattern 101 is recorded by a plurality of nozzles on the downstream end side. On the other hand, distance B1 is the distance between pattern 91 and the dense region of pattern 222 in the main scanning direction. Each of pattern 91 and pattern 222 is recorded by different nozzles. Pattern 91 is recorded by a plurality of nozzles on the downstream end side. Pattern 222 is recorded by multiple nozzles on the upstream end side. In the example shown in Figure 12, distance A1 is the distance between the center of pattern 91 and the center of the darker region of pattern 101, but is not limited to this. Distance A1 may be the distance between the center of pattern 91 and the center of the lighter-colored region of pattern 101 that is closer to pattern 91. Alternatively, distance A1 may be the distance between the center of pattern 91 and the center of the lighter-colored region of pattern 101 that is further away from pattern 91. Distance B1 may be the distance at the same location as distance A1.

[0061] Next, in S1305, the CPU 102 derives the amount x of the shift in the recording position of the reaction solution in the θ rotation direction of the recording head 24b, based on the distances A1 and B1 obtained in the processes of S1303 and S1304. Here, x is the value calculated from B1-A1. That is, the amount x of the shift in the recording position of the reaction solution in the θ rotation direction of the recording head 24b has a sign that is positive or negative depending on the tilt direction of the recording head 24b. For example, if B1-A1 is positive, pattern 222 is shifted to the right relative to pattern 101. On the other hand, if B1-A1 is negative, pattern 222 is shifted to the left relative to pattern 101. Next, in S1306, the CPU 102 derives the correction amount for the recording position of the reaction solution based on the amount x of the shift in the recording position of the reaction solution derived in the process of S1305. Next, in S1307, the CPU 102 stores the correction amount derived in the processing of S1306 in the memory 108. The CPU 102 then terminates this process. When a new job is input, the ejection timing of the reaction liquid ejected from the recording head 24b can be delayed or advanced based on the correction amount. Through this series of operations, even in the case of the recording head 24b that ejects a colorless, transparent liquid such as the reaction liquid, it is possible to obtain the θ correction amount and correct the ejection position on the recording medium. Subsequently, when a new print job is input, the ejection positions of the ink and reaction liquid should be corrected for each print job based on the saved correction amount, and printing should be performed at the corrected ejection positions.

[0062] (Second Embodiment) In the configuration shown in Figure 2, the detection area of ​​the optical sensor 200 in the Y direction is smaller than the recording area of ​​the recording head 24. In this case, the recording medium P needs to be transported between reading the adjustment pattern recorded at the downstream end of the recording head 24b and reading the adjustment pattern recorded at the upstream end of the recording head 24b. If a shift in the X direction occurs during such transport, it may become difficult to determine the tilt of the recording head 24b with high accuracy. In view of this problem, in this embodiment, as shown in Figure 14, the origin pattern is also recorded at the nozzle group 33up-end at the upstream end of the recording head 24. By utilizing the origin pattern recorded at the nozzle group 33up-end at the upstream end of the recording head 24, the θ correction amount can be detected in the coordinate system of the new origin pattern, pattern 140, and the adjustment pattern (pattern 141). In other words, when reading pattern 140 and the adjustment pattern (pattern 141), both are affected by transport errors. Therefore, if pattern 141 is in the same coordinate system as pattern 140, the effect of transport errors can be ignored. Thus, it becomes possible to focus on obtaining the θ correction amount in the coordinate system with pattern 91 as the origin pattern and the coordinate system with pattern 140 as the origin pattern. Consequently, it is possible to obtain a highly accurate θ correction amount. The details are explained below.

[0063] (Adjustment method in the second embodiment) In the second embodiment, it is assumed that a value a (the amount of deviation between the upstream and downstream sides of the recording head 24a), which is the amount of deviation between the origin pattern recorded at the upstream end of the recording head 24 and the origin pattern recorded at the downstream end of the recording head 24, is pre-stored in the recording device 10. The value a is a value predetermined due to the θ correction amount. In the second embodiment, when recording the following pattern, it is assumed that the ejection positions of the color ink and reaction solution are not corrected. Figure 14 is a diagram showing the origin pattern and adjustment pattern on the recording medium P by the recording head 24 according to the second embodiment. In Figure 14, in addition to the pattern 91 recorded at the downstream end, a pattern 140 recorded at the upstream end is added. Pattern 140, like pattern 91, represents the origin pattern. Also in Figure 14, pattern 141 is recorded at the upstream end. Pattern 141, like pattern 222 in Figure 12, represents the adjustment pattern recorded at the upstream end, but unlike pattern 222, the ejection position of the color ink is not corrected. Therefore, each region where color ink is recorded in pattern 140 and pattern 141 is shifted in the -X direction. On the other hand, the upstream end of recording head 24b is shifted in the +X direction relative to the downstream end of recording head 24b. Therefore, a region can be formed where the reaction solution is not ejected from the upstream end side of recording head 24b, and color ink is ejected from the upstream end side of recording head 24a. Also, the dense region of the adjustment pattern on the upstream end side is shifted in the +X direction relative to the dense region of the adjustment pattern on the downstream end side, similar to Figure 12. Pattern 140 in Figure 14 is a pattern recorded with K ink using the dot arrangement shown in Figure 10(a) and a pattern recorded with reaction solution using the dot arrangement shown in Figure 10(b). As shown in Figure 7, recording heads 24a and 24b are mounted tilted in opposite directions in the θ rotation direction. Therefore, the origin pattern recorded by the nozzle group 33up-end at the upstream end of the recording head 24a is recorded shifted in the -X direction relative to the origin pattern recorded by the nozzle group 33down-end at the downstream end of the recording head 24a. That is, pattern 140 is recorded shifted in the -X direction relative to pattern 91.On the other hand, the dense region of the adjustment pattern recorded by the nozzle group 33up-end at the upstream end of the recording head 24b is recorded shifted in the +X direction relative to the dense region of the adjustment pattern recorded by the nozzle group 33down-end at the downstream end of the recording head 24b. That is, the dense region of pattern 141 is recorded shifted in the +X direction relative to the dense region of pattern 101. Strictly speaking, a less dense area also appears at the left end of pattern 140 where no reaction solution is ejected, but since the amount of reaction solution ejected in pattern 140 is relatively small compared to the amount of ink ejected, its illustration and explanation are omitted.

[0064] Furthermore, transport errors may occur as the recording medium P is transported along the Y direction. In this case, in the second embodiment, pattern 140 and pattern 141 are detected together by the optical sensor 200, and after the transport operation, pattern 91 and pattern 101 are detected together by the optical sensor 200. In other words, the optical sensor 200 moves in the X direction and detects the origin pattern and adjustment pattern located in the X direction. In this way, by detecting the origin pattern each time a pattern is detected, the distance in the X direction between the origin pattern and the adjustment pattern at the time of detection by the same scan can be determined, and the transport error in the Y direction that may occur between detections can be substantially ignored. Therefore, with the pattern according to the second embodiment, it is possible to detect the pattern while ignoring the transport error.

[0065] Figure 15 is a flowchart illustrating the process of acquiring the θ correction amount of the recording head 24b according to the second embodiment. The series of processes shown in the flowchart of Figure 15 are performed by the CPU 102 expanding the program code stored in the ROM 104 into the RAM 106 and executing it. Alternatively, some or all of the functions of the steps in Figure 15 may be performed by hardware such as an ASIC or electrical circuit. In the description of each process, the symbol S means a step in the flowchart.

[0066] In S1501, the CPU 102 records the patterns. The memory 108 stores, for example, an origin pattern and an adjustment pattern as patterns. In the S1501 process, the origin pattern and the adjustment pattern are recorded as shown in Figure 14. The pattern recording may be performed in one scan by the carriage 22, as in the first embodiment, or in multiple scans. Next, in S1502, while scanning the carriage 22, the CPU 102 uses the optical sensor 200 to detect the optical characteristics of the origin pattern and adjustment pattern recorded on the recording medium P. The optical characteristics detected in the S1502 process are, for example, optical characteristics in which the ejection position in the X direction and the reflection intensity are associated, as shown in Figure 11. Such detection is performed for the pattern downstream of the recording head 24 and the pattern upstream of the recording head 24, respectively.

[0067] Next, in S1503, the CPU 102 performs the following processing based on the optical characteristics of the adjustment pattern detected by the processing in S1502, as shown in Figure 11. Specifically, the CPU 102 obtains the distance A1 between the origin pattern recorded at the nozzle group 33down-end and the adjustment pattern recorded at the nozzle group 33down-end.

[0068] Next, in S1504, the CPU 102 performs the following processing based on the optical characteristics of the adjustment pattern detected by the processing in S1502. Specifically, the CPU 102 obtains the distance B2 between the origin pattern recorded by the nozzle group 33up-end and the adjustment pattern recorded by the nozzle group 33up-end.

[0069] Next, in S1505, the CPU 102 derives the amount of displacement x of the recording position of the reaction solution in the θ rotation direction of the recording head 24b, based on the distances A1 and B2 obtained in the S1503 and S1504 processes. Here, the displacement x of the recording position of the reaction solution in the θ rotation direction of the recording head 24b is the value calculated as B2-A1-a. The value a is the amount of displacement between the origin pattern recorded by the nozzle group 33down-end and the origin pattern recorded by the nozzle group 33up-end. The value a is the amount of displacement in the rotation direction of the recording head 24a. The value a can be obtained in advance by a conventional adjustment method, but it can also be determined as the amount of displacement between the centers of the two origin patterns. Next, in S1506, the CPU 102 derives the correction amount for the recording position of the reaction solution based on the amount of displacement x of the recording position of the reaction solution derived in the S1505 process. Next, in S1507, the CPU 102 stores the correction amount derived in the S1506 process in the memory 108. The CPU 102 then terminates this process. With this series of operations, even if errors in the X direction are included in the transport operation between the reading scan for the upstream adjustment pattern and the reading scan for the downstream adjustment pattern, the θ correction amount can be obtained with high accuracy. Subsequently, when a new print job is input, the ejection positions of the ink and reaction solution are corrected for each print job based on the saved correction amount, and printing is performed at the corrected ejection positions.

[0070] (Third embodiment) Figure 16 shows the origin pattern and adjustment pattern on the recording medium P by the recording head 24 according to the third embodiment. In this embodiment, the detection error of the adjustment pattern position is reduced by increasing the number of patches included in the adjustment pattern, and a highly accurate θ correction amount is obtained. Details will be described below.

[0071] (Adjustment method in the third embodiment) In the third embodiment, it is assumed that a value a, which is the amount of deviation between the origin pattern recorded at the upstream end of the recording head 24a and the origin pattern recorded at the downstream end of the recording head 24, is pre-stored in the recording device 10. The value a is the same as in the second embodiment, so its explanation is omitted. Also, in the third embodiment, as in the second embodiment, it is assumed that the ejection positions of the color ink and reaction liquid are not corrected. In Figure 16, as in Figure 14, an origin pattern recorded at the upstream end of the recording head 24 is added in addition to the origin pattern recorded at the downstream end of the recording head 24. Also, in Figure 16, since the color ink is recorded by the recording head 24a, each region recorded by the inks of the origin pattern and adjustment pattern is shifted in the -X direction. On the other hand, the upstream end of the recording head 24b is shifted in the +X direction relative to the downstream end of the recording head 24b. Therefore, a region can be formed in which the reaction liquid is not ejected from the upstream end side of the recording head 24b, and the color ink is ejected from the upstream end side of the recording head 24a. Furthermore, each dense region of the adjustment pattern on the upstream end is shifted in the +X direction relative to each dense region of the adjustment pattern on the downstream end. Specifically, pattern 161 in Figure 16 is a pattern in which multiple patterns 921 and 922 from Figure 9 are arranged alternately in the X direction. On the other hand, pattern 162 in Figure 16 is a pattern in which multiple patterns 931 and 932 from Figure 9 are arranged alternately in the X direction. Recording heads 24a and 24b in Figure 7 are mounted offset in the θ rotation direction. Therefore, the origin pattern recorded on the upstream side of recording head 24 is recorded shifted in the -X direction relative to the origin pattern recorded on the downstream side of recording head 24. Also, each dense region of the adjustment pattern recorded on the upstream side of recording head 24 is recorded shifted in the +X direction relative to each dense region of the adjustment pattern recorded on the downstream side of recording head 24.

[0072] Figure 17 is a flowchart illustrating the process of acquiring the θ correction amount of the recording head 24b according to the third embodiment. The series of processes shown in the flowchart of Figure 17 are performed by the CPU 102 expanding the program code stored in the ROM 104 into the RAM 106 and executing it. Alternatively, some or all of the functions of the steps in Figure 17 may be performed by hardware such as an ASIC or electrical circuit. In the description of each process, the symbol S means a step in the flowchart.

[0073] In S1701, the CPU 102 records the pattern. The memory 108 stores, for example, an origin pattern and an adjustment pattern as patterns. In the S1701 process, the origin pattern and the adjustment pattern are recorded as shown in Figure 16. The pattern recording may be performed in one scan by the carriage 22, as in the above embodiment, or in multiple scans. Next, in S1702, while scanning the carriage 22, the CPU 102 uses the optical sensor 200 to detect the optical characteristics of the origin pattern and adjustment pattern recorded on the recording medium P. The optical characteristics detected in the S1702 process are, for example, optical characteristics in which the ejection position in the X direction and the reflection intensity are associated, as shown in Figure 11. Such detection is performed for the pattern downstream of the recording head 24 and the pattern upstream of the recording head 24, respectively.

[0074] Next, in S1703, the CPU 102 performs the following processing based on the optical characteristics of the adjustment pattern detected by the processing in S1702, as shown in Figure 11. Specifically, the CPU 102 obtains the distances A1, A2, A3, A4, and A5 between the origin pattern recorded at the nozzle group 33down-end and the adjustment pattern recorded at the nozzle group 33down-end.

[0075] Next, in S1704, the CPU 102 performs the following processing based on the optical characteristics of the adjustment pattern detected by the processing in S1702. Specifically, the CPU 102 obtains the distances B1, B2, B3, B4, and B5 between the origin pattern recorded by the nozzle group 33up-end and the adjustment pattern recorded by the nozzle group 33up-end.

[0076] Next, in S1705, the CPU 102 obtains the displacement amounts x1, x2, x3, x4, x5 of the recording position of the reaction solution in the θ rotation direction of the recording head 24b, based on the distances obtained in each of the processes in S1703 and S1704. Here, x1 is the value calculated as B1-A1-a. x2 is the value calculated as B2-A2-a. x3 is the value calculated as B3-A3-a. x4 is the value calculated as B4-A4-a. x5 is the value calculated as B5-A5-a. The value a is the displacement amount between the origin pattern recorded by the nozzle group 33down-end and the origin pattern recorded by the nozzle group 33up-end. The value a is the displacement amount in the rotation direction of the recording head 24a. The value a can be obtained by a conventional adjustment method, but it can also be determined as the displacement amount of the centers of the two origin patterns. Next, in S1706, the CPU 102 derives the average value of the deviation amounts x1, x2, x3, x4, x5 of the reaction solution recording position derived in the S1705 process. Next, in S1707, the CPU 102 derives a correction amount for the reaction solution recording position based on the average value of the deviation amounts of the reaction solution discharge position derived in the S1706 process. Next, in S1708, the CPU 102 saves the correction amount calculated in the S1707 process to the memory 108. The CPU 102 then terminates this process. With this series of operations, even if the detection accuracy of the discharge position of the adjustment pattern is low, the correction amount is derived based on the average value obtained using multiple dense areas, so the θ correction amount can be obtained with high accuracy. After that, when a new print job is input, the discharge positions of the ink and reaction solution are corrected for each print job based on the saved correction amount, and printing is performed at the corrected discharge position. Furthermore, if any of the reaction solution discharge position deviations x1, x2, x3, x4, x5 exceed a preset tolerance range, an error notification may be sent to the control panel 124, indicating an error in the nozzle of the recording head 24b. If any of the reaction solution discharge position deviations x1, x2, x3, x4, x5 exceed a preset tolerance range, in S1706, the average value may be derived by excluding the deviation exceeding the tolerance range. For example, if x5 is a deviation exceeding the tolerance range, the average value is derived from x1, x2, x3, x4.

[0077] (Fourth embodiment) Figure 18 shows the origin pattern, adjustment pattern, and reference pattern on the recording medium P by the recording head 24 according to the fourth embodiment. In this embodiment, the positional error of the adjustment pattern is reduced by calculating the amount of deviation from the reference pattern for each pattern, and a more accurate θ correction amount is obtained. Details will be described below.

[0078] (Adjustment method in the fourth embodiment) In the fourth embodiment, it is assumed that a value a, which is the amount of deviation between the origin pattern recorded at the upstream end of the recording head 24 and the origin pattern recorded at the downstream end of the recording head 24, is pre-stored in the recording device 10. The value a is the same as in the second and third embodiments, so its explanation is omitted. Also, in the fourth embodiment, as in the second and third embodiments, it is assumed that the ejection positions of the color ink and reaction liquid are not corrected. In Figure 18, multiple patterns similar to the origin pattern are further recorded in the X direction as a reference pattern. It is preferable that the ink color of the ink used to record the reference pattern is the same as the ink color used to record the origin pattern. Here, K ink is assumed as the reference ink. Pattern 181 is the reference pattern recorded at the nozzle group 33 down-end. Pattern 182 is the reference pattern recorded at the nozzle group 33 up-end. Pattern 161 is the adjustment pattern recorded at the nozzle group 33 down-end. Pattern 162 is the adjustment pattern recorded at the nozzle group 33 up-end. Each recording patch included in the reference pattern (Pattern 181) and the reference pattern (Pattern 182) is recorded with K ink using the dot arrangement in Figure 10(a) and with the reaction solution using the dot arrangement in Figure 10(b).

[0079] As shown in Figure 7, recording heads 24a and 24b are mounted offset in the θ rotation direction. Therefore, the origin pattern and reference pattern recorded on the upstream end of recording head 24 are recorded offset in the -X direction relative to the origin pattern and reference pattern recorded on the downstream end of recording head 24. On the other hand, each dense region of the adjustment pattern recorded on the upstream end of recording head 24 is recorded offset in the +X direction relative to each dense region of the adjustment pattern recorded on the downstream end of recording head 24.

[0080] Figure 19 is a flowchart illustrating the process of acquiring the θ correction amount of the recording head 24b according to the fourth embodiment. The series of processes shown in the flowchart of Figure 19 are performed by the CPU 102 expanding the program code stored in the ROM 104 into the RAM 106 and executing it. Alternatively, some or all of the functions of the steps in Figure 19 may be performed by hardware such as an ASIC or electrical circuit. In the description of each process, the symbol S means a step in the flowchart.

[0081] In S1901, the CPU 102 records the patterns. The memory 108 stores, for example, an origin pattern, a reference pattern, and an adjustment pattern as patterns. In the process of S1901, the origin pattern, reference pattern, and adjustment pattern are recorded as shown in Figure 18. The pattern recording may be performed in a single scan by the carriage 22, as in the above embodiment, or in multiple scans. Next, in S1902, while scanning the carriage 22, the CPU 102 uses the optical sensor 200 to detect the optical characteristics of the origin pattern, reference pattern, and adjustment pattern recorded on the recording medium P.

[0082] Next, in S1903, the CPU 102 performs the following processing based on the optical characteristics of the reference pattern and adjustment pattern detected in the processing of S1902. Specifically, the CPU 102 obtains the distances A1, A2, A3, A4, and A5 between the origin pattern recorded at the nozzle group 33down-end and the adjustment pattern recorded at the nozzle group 33down-end.

[0083] Next, in S1904, the CPU 102 performs the following processing based on the optical characteristics of the reference pattern and adjustment pattern detected in the processing of S1902. Specifically, the CPU 102 obtains the distances B1, B2, B3, B4, and B5 between the origin pattern recorded by the nozzle group 33up-end and the adjustment pattern recorded by the nozzle group 33up-end.

[0084] Next, in S1905, the CPU 102 performs the following processing based on the optical characteristics of the origin pattern and reference pattern detected in the processing of S1902. Specifically, the CPU 102 obtains the distances C1, C2, C3, C4, and C5 between the origin pattern recorded at the nozzle group 33down-end and the reference pattern recorded at the nozzle group 33down-end.

[0085] Next, in S1906, the CPU 102 performs the following processing based on the optical properties of the origin pattern and reference pattern detected in the processing of S1902. Specifically, the CPU 102 obtains the distances C'1, C'2, C'3, C'4, and C'5 between the origin pattern recorded by the nozzle group 33up-end and the reference pattern recorded by the nozzle group 33up-end.

[0086] Next, in S1907, the CPU 102 derives the displacement amounts x1, x2, x3, x4, and x5 of the recording position of the reaction solution in the θ rotation direction of the recording head 24b, based on the distances obtained in S1903, S1904, S1905, and S1906. Here, x1 is the value calculated as (B1-C'1)-(A1-C1)-a. x2 is the value calculated as (B2-C'2)-(A2-C2)-a. x3 is the value calculated as (B3-C'3)-(A3-C3)-a. x4 is the value calculated as (B4-C'4)-(A4-C4)-a. x5 is the value calculated as (B5-C'5)-(A5-C5)-a. The value a is the displacement amount in the rotation direction of the recording head 24a. The value a can be obtained by a conventional adjustment method, but it can also be determined as the amount of displacement between the centers of the two origin patterns. Next, in S1908, the CPU 102 derives the average value of the displacement amounts x1, x2, x3, x4, x5 of the reaction solution recording position derived in the process of S1907. Next, in S1909, the CPU 102 derives the correction amount for the recording position of the reaction solution based on the average value of the displacement amounts for the recording position of the reaction solution derived in the process of S1908. Next, in S1910, the CPU 102 stores the correction amount derived in the process of S1909 in the memory 108. The CPU 102 then terminates this process. Through this series of operations, the displacement amount of the adjustment pattern is derived using a reference pattern recorded by the nozzle group on the same side. Therefore, it is possible to further reduce the pattern detection error than in the above embodiment, and it is possible to obtain the θ correction amount with higher accuracy even when only the reaction solution is filled in one of the recording heads 24b. Subsequently, when a new print job is entered, the ink and reaction liquid ejection positions should be corrected for each print job based on the saved correction amounts, and it should be decided to print at the corrected ejection positions. If any of the reaction liquid ejection position deviations x1, x2, x3, x4, x5 exceed a preset tolerance range, an error notification may be sent to the control panel 124, indicating an error in the nozzle of the recording head 24b. If any of the reaction liquid ejection position deviations x1, x2, x3, x4, x5 exceed a preset tolerance range, the average value may be derived in S1908 by excluding those that exceed the tolerance range.For example, if x5 is a deviation exceeding the acceptable range, the average value is derived from x1, x2, x3, and x4.

[0087] (Fifth embodiment) In the embodiments described above, we have described a method for obtaining the θ correction amount in the recording head 24b that ejects the reaction solution. For example, there are cases where a recording head ejects only light color inks, such as light magenta ink (hereinafter referred to as light M ink), which have low detection accuracy by the optical sensor 200. In this case, it is necessary to obtain the θ correction amount in that recording head as well. Here, we will explain a method for obtaining the θ correction amount for light color inks. That is, we will describe a use case in which the recording head 24b is filled with light color ink that has a relatively lower saturation than the ink ejected from the recording head 24a.

[0088] Figure 20 shows a use case with low pattern saturation. Figure 20 also shows the acquisition process for acquiring the amount of deviation of the ejection position of the color ink using the optical sensor 200 in the adjustment method of the fifth embodiment, and the pattern recorded during the acquisition process. Pattern 201 shows the origin pattern recorded with normal ink. Patterns 202 and 203 show the adjustment patterns recorded with light-colored ink. Figure 20 shows an example in which patterns 201 and 202 are recorded at the nozzle group 33down-end of the recording head 24b that ejects light-colored ink, and pattern 203 is recorded at the nozzle group 33up-end of the recording head 24b that ejects light-colored ink. It is preferable to use K ink, which has high sensor detection accuracy, but other color inks may also be used. In addition, a reaction solution may be added along with the color ink. A single light-colored ink to be adjusted is used for patterns 202 and 203. A reaction solution may also be added to these patterns. Pattern 201 is the same as pattern 91 in Figure 9, so its explanation is omitted. The color ink in the entire ejection area of ​​pattern 202 and pattern 203 is recorded using the dot arrangement shown in Figure 10(a). In this embodiment, the dot arrangement shown in Figure 10 is used, but the dot arrangement may be changed depending on the recording environment.

[0089] Figure 21 shows the optical properties of the pattern in Figure 20. Figure 21 shows the optical properties when the pattern in Figure 20 is recorded on a gloss polyvinyl chloride film. Pattern 212 shows a pattern in which patterns 201 and 202 are recorded on the same area in the Y direction on the recording medium with the same scan. The boundaries of each area, such as the non-ejected area S1, ejected area S2, and ejected area S5, can be detected by the optical sensor 200 from the difference in reflection intensity between the ejected area and the non-ejected area, making it possible to identify the position of each ejected area. That is, by using patches with different reflection intensities, the boundaries of the areas in which each patch is recorded can be detected.

[0090] (Adjustment method in the fifth embodiment) In the fifth embodiment, it is assumed that the recording head 24a is filled with color ink and the recording head 24b is filled with light M ink. Figure 22 shows the origin pattern and adjustment pattern on the recording medium P when the recording head 24b that ejects the light M ink to be corrected is mounted at an angle. It is assumed that the recording position of the recording head 24a has been corrected as in the first embodiment. On the other hand, because the recording head 24b is mounted shifted in the θ rotation direction, the pattern recorded at the nozzle group 33up-end is recorded shifted in the +X direction relative to the pattern recorded at the nozzle group 33down-end. As explained in Figure 21, the position in the X direction of each region can be obtained based on the change point of reflection intensity, and the θ correction amount of the recording head 24b can be obtained. Therefore, in the fifth embodiment, it is possible to obtain the θ correction amount even when only light color ink is filled in one of the recording heads 24b.

[0091] <Other Embodiments> Although various examples and embodiments of this disclosure have been described above, the spirit and scope of this disclosure are not limited to the specific descriptions herein. This disclosure is not limited to the embodiments described above, and various modifications may be made. Furthermore, this disclosure may combine some of the embodiments described above as appropriate.

[0092] (Variation 1) For example, while one example has been described in which each process of this embodiment is executed by at least one of the host device 114 and the control unit 100 of the recording device 10, the embodiment is not limited thereto. For example, at least one of the host device 114 and the control unit 100 of the recording device 10 may be able to communicate with a cloud server that provides cloud services that perform various image formation services. With such a configuration, each process of this embodiment can be executed in cooperation with the cloud server in addition to the control unit 100 of the host device 114 and the recording device 10.

[0093] (Modification 2) Furthermore, in the first embodiment, for example, an example was described in which the median value between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4 is assumed to be the point of change between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4. The position of each discharge region S3, S4 in the adjustment pattern is characterized by this point of change, but the point of change is not limited to the median value between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4. Preferably, it is the midpoint 50% between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4, so an example was described in which the median value between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4 is used as the point of change, but a certain tolerance range may be provided at the midpoint 50%. For example, the tolerance range may be 10% before or after 50%. That is, the point of change may be between 40% and 60% between the reflectance intensity of discharge region S3 and the reflectance intensity of discharge region S4. On the other hand, the median value between the reflection intensity of the ejection region S2 where the origin pattern (pattern 91) is recorded and the reflection intensity of the non-ejection region S1 was assumed to be the point of change between the reflection intensity of the ejection region S2 and the non-ejection region S1, but this is not limited to this. Because the origin pattern (pattern 91) produces contrast, the boundary between the ejection region S2 and the non-ejection region S1 is clearly visible. Therefore, for example, the point between the reflection intensity of the ejection region S2 and the reflection intensity of the non-ejection region S1 could be assumed to be the point of change between the reflection intensity of the ejection region S2 and the reflection intensity of the non-ejection region S1, from the lowest reflection intensity to 35% of the maximum reflection intensity within the reflection intensity of the ejection region S2.

[0094] (Variation 3) Furthermore, in this embodiment, the boundary of adjacent regions was detected based on the reflection intensity obtained from the optical sensor 200, but this is not limited to this. For example, the concentration of the color ink or reaction solution ejected into the region may be calculated based on the reflection intensity obtained from the optical sensor 200, and the boundary of adjacent regions may be detected based on this calculated concentration.

[0095] (Modification 4) Furthermore, although this embodiment describes an example in which the first, second, third, fourth, and fifth embodiments are each implemented separately, the embodiment is not limited to these. For example, an embodiment may be a combination of at least two embodiments from the first, second, third, fourth, and fifth embodiments.

[0096] For example, the fourth embodiment describes a case where there are two origin patterns, but it is not limited to this. As described in the first embodiment, the correction process may be performed using one origin pattern recorded by the nozzle group 33down-end. In other words, the fourth embodiment may be a combination of the first embodiment. Similarly, as an embodiment combining the third embodiment and the first embodiment, the correction process may be performed using one origin pattern recorded by the nozzle group 33down-end, as described in the first embodiment.

[0097] (Variation 5) Furthermore, although this embodiment describes an example in which a pattern is recorded from at least one of the nozzle group 33down-end and the nozzle group 33up-end of the recording head 24b, the embodiment is not limited to this. For example, a pattern may be recorded using a first nozzle group consisting of some nozzles 32 from among a plurality of nozzles 32, and a second nozzle group consisting of some other nozzles 32 located upstream or downstream of the first nozzle group.

[0098] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions. Furthermore, the program may be recorded on a recording medium readable by a computer and provided.

[0099] The disclosure of this embodiment includes configurations such as the method for acquiring the correction value, the program, and the device for acquiring the correction value described below.

[0100] <Configuration 1> A recording device that records an image on a recording medium while scanning a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and a second recording head having a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, a method for obtaining a correction value for correcting the ejection position deviation of the second recording head in the rotational direction with respect to the first direction, wherein the first recording head has a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and the second recording head has a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, A recording step of recording a predetermined correction pattern on the recording medium by scanning the first recording head and the second recording head in the second direction, An acquisition step of obtaining the amount of displacement of the ejection position in the rotational direction of the second recording head by detecting the correction pattern while scanning the optical sensor in the second direction, A derivation step of deriving a correction value for correcting the displacement of the ejection position of the second recording head in the rotational direction, based on the amount of displacement of the ejection position of the second recording head in the rotational direction, Includes, In the aforementioned recording process, The origin pattern is recorded using the first nozzle array, A first adjustment pattern is recorded using an adjacent group of first nozzles from among the plurality of second nozzles included in the second nozzle row. A second adjustment pattern is recorded using an adjacent second nozzle group, different from the first nozzle group, among the plurality of second nozzles included in the second nozzle row. In the acquisition step, based on the detection result of the correction pattern, The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the first adjustment pattern, The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the second adjustment pattern, A method for obtaining a correction value, characterized by obtaining the amount of displacement of the ejection position in the rotational direction of the second recording head from the difference.

[0101] <Configuration 2> The first ink contains a colorant, and the second ink reacts with the first ink to change the area factor of the first ink. In the aforementioned recording process, In the first adjustment pattern, the first ink is recorded using the first nozzle row so as to overlap with the recording area of ​​the first nozzle group. In the second adjustment pattern, the first ink is recorded using the first nozzle row so as to overlap with the recording area of ​​the second nozzle group. The method for obtaining a correction value according to Configuration 1, characterized in that the acquisition step involves obtaining the amount of deviation of the discharge position of the second recording head in the rotational direction based on the difference between the distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the position in the first adjustment pattern where the concentration changes, and the distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the position in the second adjustment pattern where the concentration changes.

[0102] <Structure 3> The method for obtaining a correction value according to configuration 2, characterized in that the origin pattern includes a first origin pattern recorded at the same position as the first adjustment pattern in the first direction, and a second origin pattern recorded at the same position as the second adjustment pattern in the first direction.

[0103] <Structure 4> In the aforementioned recording process, In each of the first and second adjustment patterns, two types of regions with different recording densities of the second ink are alternately recorded in the second direction. In the acquisition process described above, For multiple positions where the concentration changes in the first adjustment pattern, the distance from the first origin pattern is obtained to calculate the first average value. For multiple positions where the concentration changes in the second adjustment pattern, the distance from the second origin pattern is obtained to calculate the second average value. A method for obtaining a correction value according to configuration 3, characterized in that the amount of displacement of the ejection position in the rotational direction of the second recording head is obtained based on the difference between the first average value and the second average value.

[0104] <Composition 5> In the aforementioned recording process, In each of the first and second adjustment patterns, two types of regions with different recording densities of the second ink are alternately recorded in the second direction. Near the first adjustment pattern, a first reference pattern is recorded using the first nozzle row, which includes a third origin pattern and a plurality of patches arranged in the second direction relative to the third origin pattern. Near the second adjustment pattern, a second reference pattern is recorded using the first nozzle row, which includes a fourth origin pattern and a plurality of patches arranged in the second direction relative to the fourth origin pattern. In the acquisition process described above, The distance from the third origin pattern to multiple patch locations included in the first reference pattern, The distance from the first origin pattern to multiple positions in the first adjustment pattern where the concentration changes, and the difference between each of these, The distance from the fourth origin pattern to multiple patch locations included in the second reference pattern, A method for obtaining a correction value according to configuration 3, characterized in that the amount of displacement of the ejection position in the rotational direction of the second recording head is obtained based on the difference between the distance from the second origin pattern to a plurality of positions in the second adjustment pattern where the concentration changes, and each of these differences.

[0105] <Composition 6> The method for obtaining a correction value according to configuration 1, characterized in that the first ink and the second ink contain a colorant.

[0106] <Composition 7> The method for obtaining a correction value according to configuration 1, further comprising a storage step of storing the correction value derived in the derivation step in memory.

[0107] <Structure 8> The method for obtaining a correction value according to Configuration 1, characterized in that the first nozzle group is a group of nozzles located at one end of the second nozzle row, and the second nozzle group is a group of nozzles located at the other end of the second nozzle row.

[0108] <Composition 9> A method for obtaining a correction value according to configuration 1, further comprising a control step of controlling the ejection timing of the second ink from the second recording head based on the correction value.

[0109] <Composition 10> A program for causing a computer to perform each step of the method for obtaining correction values ​​described in any one of configurations 1 to 9.

[0110] <Composition 11> A recording device for recording an image on a recording medium while scanning a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and a second recording head having a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, wherein the device acquires a correction value for correcting the displacement of the ejection position of the second recording head in the rotational direction with respect to the first direction, A recording means for recording a predetermined correction pattern on the recording medium by scanning the first recording head and the second recording head in the second direction, An acquisition means for acquiring the amount of displacement of the ejection position in the rotational direction of the second recording head by detecting the correction pattern while scanning the optical sensor in the second direction, A derivation means for deriving a correction value for correcting the displacement of the ejection position of the second recording head in the rotational direction, based on the amount of displacement of the ejection position of the second recording head in the rotational direction, Equipped with, The recording means is The origin pattern is recorded using the first nozzle array, A first adjustment pattern is recorded using an adjacent group of first nozzles from among the plurality of second nozzles included in the second nozzle row. A second adjustment pattern is recorded using an adjacent second nozzle group, different from the first nozzle group, among the plurality of second nozzles included in the second nozzle row. Based on the detection result of the correction pattern, the acquisition means The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the first adjustment pattern, The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the second adjustment pattern, A device for acquiring a correction value, characterized by obtaining the amount of displacement of the ejection position in the rotational direction of the second recording head from the difference.

[0111] <Composition 12> The device for acquiring a correction value according to configuration 11, further comprising the aforementioned optical sensor. [Explanation of Symbols]

[0112] 10 Recording device 14 Records Section 22 Carriage 24 recording heads

Claims

1. A recording device that records an image on a recording medium while scanning a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and a second recording head having a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, a method for obtaining a correction value for correcting the ejection position deviation of the second recording head in the rotational direction with respect to the first direction, wherein the first recording head has a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and a second recording head has a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, A recording step of recording a predetermined correction pattern on the recording medium by scanning the first recording head and the second recording head in the second direction, An acquisition step of acquiring the amount of displacement of the ejection position in the rotational direction of the second recording head by detecting the correction pattern while scanning the optical sensor in the second direction, A derivation step of deriving a correction value for correcting the displacement of the ejection position in the rotational direction of the second recording head, based on the amount of displacement of the ejection position in the rotational direction of the second recording head, Includes, In the aforementioned recording process, The origin pattern is recorded using the first nozzle array, A first adjustment pattern is recorded using an adjacent group of first nozzles from among the plurality of second nozzles included in the second nozzle row. A second adjustment pattern is recorded using an adjacent second nozzle group, different from the first nozzle group, among the plurality of second nozzles included in the second nozzle row. In the acquisition step, based on the detection result of the correction pattern, The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the first adjustment pattern, The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the second adjustment pattern, A method for obtaining a correction value, characterized by obtaining the amount of displacement of the ejection position in the rotational direction of the second recording head from the difference.

2. The first ink contains a colorant, and the second ink reacts with the first ink to change the area factor of the first ink. In the aforementioned recording process, In the first adjustment pattern, the first ink is recorded using the first nozzle row so as to overlap with the recording area of ​​the first nozzle group. In the second adjustment pattern, the first ink is recorded using the first nozzle row so as to overlap with the recording area of ​​the second nozzle group. The method for obtaining a correction value according to claim 1, characterized in that the acquisition step involves obtaining the amount of deviation of the discharge position of the second recording head in the rotational direction based on the difference between the distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the position in the first adjustment pattern where the concentration changes, and the distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the position in the second adjustment pattern where the concentration changes.

3. The method for obtaining a correction value according to claim 2, characterized in that the origin pattern includes a first origin pattern recorded at the same position as the first adjustment pattern in the first direction, and a second origin pattern recorded at the same position as the second adjustment pattern in the first direction.

4. In the aforementioned recording process, In each of the first adjustment pattern and the second adjustment pattern, two types of regions with different recording densities of the second ink are alternately recorded in the second direction. In the acquisition process described above, For multiple positions in the first adjustment pattern where the concentration changes, the distance from the first origin pattern is obtained to calculate the first average value. For multiple positions where the concentration changes in the second adjustment pattern, the distance from the second origin pattern is obtained to calculate the second average value. The method for obtaining a correction value according to claim 3, characterized in that the amount of deviation of the ejection position in the rotational direction of the second recording head is obtained based on the difference between the first average value and the second average value.

5. In the aforementioned recording process, In each of the first adjustment pattern and the second adjustment pattern, two types of regions with different recording densities of the second ink are alternately recorded in the second direction. Near the first adjustment pattern, a first reference pattern is recorded using the first nozzle array, which includes a third origin pattern and a plurality of patches arranged in the second direction relative to the third origin pattern. Near the second adjustment pattern, a second reference pattern is recorded using the first nozzle array, which includes a fourth origin pattern and a plurality of patches arranged in the second direction relative to the fourth origin pattern. In the acquisition process described above, The distance from the third origin pattern to a plurality of patch positions included in the first reference pattern, The distance from the first origin pattern to multiple positions in the first adjustment pattern where the concentration changes, and the difference between each of these, The distance from the fourth origin pattern to multiple patch positions included in the second reference pattern, The method for obtaining a correction value according to claim 3, characterized in that the amount of displacement of the ejection position in the rotational direction of the second recording head is obtained based on the difference between the distance from the second origin pattern to a plurality of positions in the second adjustment pattern where the concentration changes, and each of these differences.

6. The method for obtaining a correction value according to claim 1, characterized in that the first ink and the second ink contain a colorant.

7. The method for obtaining a correction value according to claim 1, further comprising a storage step of storing the correction value derived in the derivation step in memory.

8. The method for obtaining a correction value according to claim 1, characterized in that the first nozzle group is a group of nozzles located at one end of the second nozzle row, and the second nozzle group is a group of nozzles located at the other end of the second nozzle row.

9. The method for obtaining a correction value according to claim 1, further comprising a control step of controlling the ejection timing of the second ink from the second recording head based on the correction value.

10. A program for causing a computer to perform each step of the method for obtaining a correction value as described in any one of claims 1 to 9.

11. A recording device for recording an image on a recording medium while scanning a first recording head having a first nozzle row in which a plurality of first nozzles for ejecting a first ink are arranged in a first direction, and a second recording head having a second nozzle row in which a plurality of second nozzles for ejecting a second ink having a lower density than the first ink are arranged in the first direction, wherein the device acquires a correction value for correcting the displacement of the ejection position of the second recording head in the rotational direction with respect to the first direction, A recording means for recording a predetermined correction pattern on the recording medium by scanning the first recording head and the second recording head in the second direction, An acquisition means for acquiring the amount of displacement of the ejection position in the rotational direction of the second recording head by detecting the correction pattern while scanning the optical sensor in the second direction, A derivation means for deriving a correction value for correcting the displacement of the ejection position of the second recording head in the rotational direction, based on the amount of displacement of the ejection position of the second recording head in the rotational direction, Equipped with, The recording means is The origin pattern is recorded using the first nozzle array, A first adjustment pattern is recorded using an adjacent group of first nozzles from among the plurality of second nozzles included in the second nozzle row. A second adjustment pattern is recorded using an adjacent second nozzle group, different from the first nozzle group, among the plurality of second nozzles included in the second nozzle row. Based on the detection result of the correction pattern, the acquisition means The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the first adjustment pattern, The distance in the second direction between the discharge position of the first nozzle row in the origin pattern and the discharge position of the second nozzle row in the second adjustment pattern, A device for acquiring a correction value, characterized by obtaining the amount of displacement of the ejection position in the rotational direction of the second recording head from the difference.

12. The device for acquiring a correction value according to claim 11, further comprising the aforementioned optical sensor.

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