Printing apparatus, and control method thereof

Abstract

To reduce the liquid consumption amount, medium consumption amount, and printing time required for printing a test pattern.SOLUTION: A printing apparatus comprises a recording head, a control unit, and a detection unit. The control unit performs control of forming an intermediate image including a mark portion detectable by the detection unit on a medium based on an input image during an intermediate pass among a plurality of passes, and performs control of forming a remaining image, which is part of a print image excluding the intermediate image, on the medium during a pass subsequent to the intermediate pass. The detection unit detects a state of the mark portion. The control unit is capable of executing processing based on the state of the mark portion detected by the detection unit.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a printing apparatus that performs main scanning and sub-scanning, and a control method thereof. [Background technology]

[0002] Inkjet printers that perform both main and sub-scanning are well known printing devices. To achieve high-precision bidirectional printing, Bi-d adjustment (bidirectional adjustment) is required to align the ink droplet landing positions on the forward and reverse passes. To achieve high-precision sub-scanning, paper feed adjustment is required. Density adjustment is also required to control the density of the printed image.

[0003] The inkjet printer disclosed in Patent Document 1 forms a test pattern on a recording medium to suppress unevenness in printed images caused by variations in the amount of ink ejected from the recording head and misalignment of the ink droplets landing position. The inkjet printer reads the test pattern with a reading sensor mounted on the carriage and creates correction data, thereby performing recording independently of the nozzle characteristics of each recording head. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-264194 Summary of the Invention [Problem to be solved by the invention]

[0005] However, forming the test pattern requires additional ink and media, and also involves downtime, which means that the user is unable to print the image he or she wants to print. [Means for solving the problem]

[0006] The printing device of the present invention is a printing device that forms a print image corresponding to an input image on a medium, a recording head having a nozzle array capable of ejecting liquid onto the medium; a control unit that controls a main scan that changes the relative positional relationship between the recording head and the medium along a main scan direction, a sub-scan that changes the relative positional relationship between the medium and the recording head along a sub-scan direction that intersects the main scan direction, and the ejection of the liquid from the recording head, and completes recording of the print image by the main scan in multiple passes; a detection unit that detects the state of the liquid that has landed on the medium, The control unit performing control to form an intermediate image including a mark portion detectable by the detection unit on the medium based on the input image in a middle pass among the plurality of passes; performing control to form the remaining images of the print image, excluding the intermediate image, on the medium in a pass subsequent to the intermediate pass; the detection unit detects the state of the mark unit, The control unit may be configured to execute a process based on the state of the mark portion detected by the detection unit.

[0007] A control method for a printing device of the present invention performs a main scan that changes the relative positional relationship between a medium and a recording head having a nozzle array capable of ejecting liquid onto the medium along a main scanning direction, and a sub-scan that changes the relative positional relationship between the medium and the recording head along a sub-scanning direction that intersects with the main scanning direction, ejects the liquid from the recording head, and completes recording of a print image corresponding to an input image by performing the main scanning in multiple passes, an intermediate image forming step of forming an intermediate image on the medium based on the input image during a midway pass among the plurality of passes, the intermediate image including a mark portion that can be detected by a detection unit that detects the state of the liquid that has landed on the medium; a detecting step of detecting a state of the mark portion by the detecting unit; a remaining image forming step of forming a remaining image of the print image, excluding the intermediate image, on the medium in a pass subsequent to the intermediate pass; and a processing step of performing processing based on the state of the mark portion detected by the detection unit. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically illustrating an example of a printing device. [Figure 2] FIG. 2 is a diagram schematically showing an example of a recording head and a mark portion. [Figure 3] FIG. 10 is a diagram schematically showing an example of forming a print image by repeating main scanning and sub-scanning. [Figure 4] 10A and 10B are diagrams illustrating an example of dot arrangement until a print image is formed in an overlapping area. [Figure 5] 10A and 10B are diagrams illustrating an example of dot arrangement until a print image is formed in an overlapping area. [Figure 6] 10A and 10B are diagrams showing examples of nozzle combinations used for each raster line in an overlapping region. [Figure 7] 10 is a flowchart illustrating an example of an adjustment process of a printing device. [Figure 8] FIG. 10 is a diagram schematically showing an example of processing based on the state of a mark portion. [Figure 9] FIG. 10 is a diagram schematically illustrating an example of path decomposition. [Figure 10] FIG. 10 is a diagram illustrating an example of partial overlap printing. [Figure 11] 10A and 10B are diagrams illustrating an example of dot arrangement until a print image is formed in an overlapping area. [Figure 12] 10A and 10B are diagrams showing examples of nozzle combinations used for each raster line in an overlapping region. [Figure 13] 10A and 10B are diagrams showing examples of nozzle combinations used for each raster line in an overlapping area when the medium transport amount is not an integer multiple of the nozzle pitch. [Figure 14] FIG. 10 is a diagram schematically showing an example of a nozzle combination when a first multi-pass region and a second multi-pass region are generated. [Figure 15] FIG. 10 is a diagram schematically showing an example of a combination of nozzles used for each raster line in the first multi-pass area. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention. Of course, the following embodiments are merely examples of the present invention, and not all of the features shown in the embodiments are necessarily essential to the solution of the invention.

[0010] (1) Summary of the aspects included in the present invention: First, an overview of the embodiments included in the present invention will be described with reference to the examples shown in Figures 1 to 15. The figures in the present application are diagrams showing examples in a schematic manner, and the scale of each part may differ from the actual scale in order to make each part of these figures large enough to be recognizable. The magnification in each direction shown in these figures may differ, and the figures may not be consistent with each other. Of course, each element of the present embodiment is not limited to the specific example indicated by a symbol. In the "Outline of the embodiments included in the present invention," the words in parentheses indicate supplementary explanations for the immediately preceding words.

[0011] [Aspect 1] As illustrated in FIGS. 1 and 3 , a printing device 1 according to one embodiment forms a print image IM3 corresponding to an input image IM0 on a medium ME0 and includes a control unit U1 and a detection unit 60. The recording head 30 has a nozzle array 33 capable of ejecting a liquid 36 onto the medium ME0. The control unit U1 controls a main scanning direction SC1 that changes the relative positional relationship between the recording head 30 and the medium ME0 along a main scanning direction D1, a sub-scanning direction SC2 that changes the relative positional relationship between the medium ME0 and the recording head 30 along a sub-scanning direction D2 that intersects the main scanning direction D1, and the ejection of the liquid 36 from the recording head 30, completing the recording of the print image IM3 through multiple passes of the main scanning direction SC1. The detection unit 60 detects the state of the liquid 36 that has landed on the medium ME0. The control unit U1 controls the formation of an intermediate image IM1 including a mark portion MA0 detectable by the detection unit 60 on the medium ME0 based on the input image IM0 in an intermediate pass (e.g., a first pass PA1) among the multiple passes. The control unit U1 controls the formation of a remaining image IM2 of the print image IM3, excluding the intermediate image IM1, on the medium ME0 in a pass (e.g., a second pass PA2) subsequent to the intermediate pass (PA1). The detection unit 60 detects the state of the mark portion MA0. The control unit U1 can execute processing based on the state of the mark portion MA0 detected by the detection unit 60, as illustrated in FIGS. 7 and 8.

[0012] In an intermediate pass (PA1) among the multiple passes, an intermediate image IM1 including a mark portion MA0 that can be detected by the detection unit 60 is formed on the medium ME0 based on the input image IM0. The state of the mark portion MA0 is detected by the detection unit 60. The remaining image IM2 of the print image IM3, excluding the intermediate image IM1, is formed on the medium ME0 in a pass (PA2) that comes after the intermediate pass (PA1). Although the mark portion MA0 will be buried in the print image IM3, it is possible to perform processing based on the state of the mark portion MA0 detected by the detection unit 60. As a result, there is no need to print a separate test pattern to adjust the printing device 1. Therefore, the above aspect can provide a printing device that can reduce the amount of liquid consumed, the amount of medium consumed, and the printing time required to print a test pattern.

[0013] Here, the medium includes various materials such as paper, fabric, and film. The detected state of the mark portion includes the position of the mark portion, the density of the mark portion, and the like. The change in the relative positional relationship described above means movement of at least one of the recording head and the medium. Therefore, during main scanning, the control unit may move the recording head along the main scanning direction without moving the medium, may move the medium along the main scanning direction without moving the recording head, or may move both the recording head and the medium along the main scanning direction. During sub-scanning, the control unit may move the medium along the sub-scanning direction without moving the recording head, may move the recording head along the sub-scanning direction without moving the medium, or may move both the recording head and the medium along the sub-scanning direction. Processing based on the state of the mark portion includes Bi-d adjustment (bidirectional adjustment) that aligns the landing position on the outbound path with the landing position on the return path, paper feed adjustment (adjustment of the medium transport amount), density adjustment, and the like. The recording method for the print image is not particularly limited as long as there is a portion of the print image that is completed in multiple passes, and may be a method in which recording is performed in both the forward and backward main scans, or a method in which recording is performed in only one of the forward and backward main scans. Recording that includes a portion of the print image that is completed in multiple passes may be multi-pass recording in which the entire print image is formed in two or more passes, or may include a portion of the print image that is completed in a single pass, such as band printing in which recording areas partially overlap. In multi-pass recording of a print image, the number of passes may vary in some areas. The relative movement amount of the recording head during sub-scanning in the sub-scanning direction may be the same each time, or may vary over multiple passes. The above remarks also apply to the following aspects.

[0014] [Aspect 2] 3, 6, etc., the multiple passes may include a first pass PA1 and a second pass PA2. The control unit U1 may control the formation of the print image IM3 so that an overlap area OL1 is generated between the image recording area in the first pass PA1 (e.g., band areas B1 and B2) and the image recording area in the second pass PA2 (e.g., band areas B2 and B3). The control unit U1 may perform control to form the mark area MA0 in the overlap area OL1 in one of the passes. In the above case, the mark portion MA0 is formed in one pass, so that the error occurring in the mark portion can be reduced compared to when the mark portion is formed in two or more passes.

[0015] In this application, the terms "first," "second," etc. are terms for distinguishing between elements among a plurality of elements having similarities, and do not indicate an order. This term also applies to the following aspects.

[0016] [Aspect 3] Here, the sub-scanning direction D2 is assumed to be the relative movement direction of the recording head 30 with respect to the medium ME0. The control unit U1 may perform control to form the mark portion MA0 in the overlapping region OL1 by ejecting the liquid 36 from a downstream nozzle NZ1 that is located furthest downstream in the sub-scanning direction D2 among a combination of multiple nozzles 34 that eject the liquid 36 onto raster lines (e.g., raster lines RL1 to RL5) along the main scanning direction D1 in the overlapping region OL1, as exemplified in FIG. 6 etc. The liquid 36 is ejected onto each raster line of the overlapping region OL1 first from the downstream nozzle NZ1, and therefore the mark portion MA0 is formed by the liquid 36 ejected onto the overlapping region OL1 from the downstream nozzle NZ1, and the state of the mark portion MA0 that is not affected by the liquid 36 ejected onto the overlapping region OL1 from the other nozzles is detected by the detection unit 60. Therefore, the above aspect makes it possible to detect the mark portion with high accuracy.

[0017] [Aspect 4] As illustrated in Figures 11 to 13, the control unit U1 may perform control to form the mark portion MA0 in the overlapping area OL1 by ejecting the liquid 36 from the nozzle that is furthest downstream in the sub-scanning direction D2 (for example, the most downstream nozzle NZ2) among the multiple nozzles 34 that eject the liquid 36 into the overlapping area OL1. Because the most downstream nozzle (NZ2) ejects liquid 36 first into the overlap region OL1, the detection unit 60 detects the state of the mark portion MA0, which is not affected by liquid 36 ejected into the overlap region OL1 from other nozzles. Furthermore, because the nozzle (NZ2) is located most downstream in the nozzle array 33, dots 38 are not formed downstream in the sub-scanning direction D2 before the mark portion MA0 is formed, allowing the state of the mark portion MA0 to be detected with high accuracy. Even if the overlap region OL1 is narrow, it is possible to overlap only one nozzle at the end of the nozzle array 33 as a countermeasure against transport errors. By designating the most downstream nozzle (NZ2) as the nozzle for forming the mark portion, the mark portion MA0 is formed regardless of the type of recording performed, eliminating the need for processing or memory storage for determining the nozzle for forming the mark portion. Therefore, the above-described embodiment provides a suitable example for detecting the mark portion with high accuracy.

[0018] [Aspect 5] 6 and other examples, the multiple passes may include a first pass PA1 and a second pass PA2 in which the recording head 30 moves in the opposite direction to the first pass PA1. The control unit U1 may perform control to form the intermediate image IM1 on the medium ME0 in the first pass PA1. The control unit U1 may perform control to form, on the medium ME0 in the second pass PA2, at least a portion of the remaining image IM2 that is on the same raster lines as the mark portion MA0 (e.g., raster lines RL2 to RL4) and that is located on the raster lines (RL2 to RL4) along the main scanning direction D1. If the raster lines passing through the mark portion MA0 are all recorded with main scanning SC1 in the same direction, the characteristics of the raster lines are more likely to appear, and the raster lines are more likely to stand out in the overall printed image IM3. In the above embodiment, after the formation of the mark portion MA0, the raster lines are recorded with main scanning SC1 in the opposite direction to that used when the mark portion MA0 was formed, so the characteristics of the raster lines are less likely to appear, and it is possible to prevent traces of the mark portion from remaining when the printed image is completed.

[0019] [Aspect 6] 14 and 15, the control unit U1 may complete the recording so that there are a first multi-pass region MP1 in which the recording is completed with a predetermined number of passes, which is two or more, and a second multi-pass region MP2 in which the recording is completed with a number of passes greater than the predetermined number of passes in the sub-scanning direction D2. The control unit U1 may perform control to form the mark portion MA0 in the first multi-pass region MP1. Since the mark portion MA0 is formed with a small number of passes, if the mark portion MA0 is formed in an area with a large number of passes, the recording characteristics of the mark portion MA0 and its surroundings will differ relatively greatly, and the mark portion MA0 may stand out in the printed image IM3. In the above embodiment, the mark portion MA0 is formed in an area with a relatively small number of passes, making it possible to make the mark portion less noticeable in the printed image.

[0020] [Aspect 7] As illustrated in Figures 2 to 5, the control unit U1 does not have to cause the recording head 30 to eject the liquid 36 onto the landing position PO1 of the medium ME0 adjacent to the mark portion MA0 when the mark portion MA0 is formed in the intermediate pass (PA1). In the above cases, the dots 38 are not formed in the intermediate image IM1 at positions adjacent to the mark portion MA0, so that the accuracy of detecting the state of the mark portion can be improved. Although not included in the above-mentioned aspect 7, even if dots 38 are formed at positions adjacent to the mark portion MA0 in the intermediate image IM1, the detection unit 60 can detect the state of the mark portion MA0 as long as the mark portion MA0 is formed in a state that can be detected by the detection unit 60. For example, the detection unit 60 can detect the state of the mark portion MA0 because the arrangement of the dots 38 is different between the mark portion MA0 and its adjacent position.

[0021] [Aspect 8] 2 to 5, the mark portion MA0 may have a pattern of the liquid 36 that has landed on the medium ME0 that is an intersecting pattern in which a main scanning line LN1 extending along the main scanning direction D1 and a sub-scanning line LN2 extending along the sub-scanning direction D2 intersect with each other. The main scanning line LN1 may have a higher density of dots 38 of the liquid 36 than an adjacent landing position PO2 in the sub-scanning direction D2 in the intermediate image IM1. The sub-scanning line LN2 may have a higher density of dots 38 of the liquid 36 than an adjacent landing position PO3 in the main scanning direction D1 in the intermediate image IM1. In the above case, it is possible to provide an example suitable for both bidirectional adjustment and medium transport amount adjustment. Here, the main scan line is not limited to a pattern in which dots are connected along the main scan direction, but may also be a pattern in which dots are arranged discretely along the main scan direction, as in the expression "dotted line." The sub-scan line is not limited to a pattern in which dots are connected along the sub-scan direction, but may also be a pattern in which dots are arranged discretely along the sub-scan direction, as in the expression "dotted line." These remarks also apply to the following aspects.

[0022] [Aspect 9] One embodiment of a control method for a printing device 1 is a printing method that performs a main scan SC1 that changes the relative positional relationship between a recording head 30 having a nozzle array 33 capable of ejecting a liquid 36 onto a medium ME0 and the medium ME0 along a main scanning direction D1, and a sub-scan SC2 that changes the relative positional relationship between the medium ME0 and the recording head 30 along a sub-scanning direction D2 that intersects with the main scanning direction D1, ejects the liquid 36 from the recording head 30, and completes recording of a print image IM3 corresponding to an input image IM0 by performing multiple passes of the main scan SC1. As shown in FIG. 7, this control method includes the following steps. (a1) An intermediate image forming process ST1 in which an intermediate image IM1 including a mark portion MA0 that can be detected by a detection unit 60 that detects the state of the liquid 36 that has landed on the medium ME0 is formed on the medium ME0 based on the input image IM0 in an intermediate pass (PA1) among the multiple passes. (a2) A detection step ST2 in which the detection unit 60 detects the state of the mark portion MA0. (a3) A remaining image forming step ST3 of forming the remaining image IM2 of the print image IM3, excluding the intermediate image IM1, on the medium ME0 in a pass (PA2) subsequent to the midway pass (PA1). (a4) A processing step ST4 in which processing is performed based on the state of the mark portion MA0 detected by the detection unit 60.

[0023] The above aspect can provide a control method that can reduce the amount of liquid consumed, the amount of medium consumed, and the printing time required to print a test pattern.

[0024] Furthermore, the above-described aspects are applicable to a printing system including the above-described printing device, a control method for the printing system, a control program for the above-described printing device, a control program for the above-described printing system, a computer-readable recording medium on which any of the above-described control programs is recorded, etc. Furthermore, the above-described printing device may be composed of multiple distributed parts.

[0025] (2) Examples of printing devices: FIG. 1 schematically illustrates a printing device 1. In this example, the printing device 1 is the printer 2 itself; however, the printing device 1 may also be a combination of the printer 2 and a host device HO1. The printer 2 may include additional elements not shown in FIG. 1. FIG. 2 schematically illustrates the nozzle array 33 of the recording head 30 and the mark portion MA0 on the medium ME0. FIG. 3 schematically illustrates the formation of a print image IM3 by repeating main scanning SC1 and sub-scanning SC2. The printer 2 in this example is a serial printer that repeats main scanning SC1 and sub-scanning SC2 to create an overlapping area between passes. FIGS. 4 and 5 schematically illustrate the dot arrangement until the print image IM3 is formed in the overlapping area OL1 between passes. FIG. 6 schematically illustrates the combination of nozzles 34 used for each raster line in the overlapping area OL1.

[0026] The printer 2 shown in Figure 1 is an inkjet printer that ejects a liquid 36 as droplets 37. The printer 2 includes a controller 10, a RAM (Random Access Memory) 21, which is a semiconductor memory, a communication I / F (interface) 22, a storage unit 23, an operation panel 24, a recording head 30, a drive unit 50, a detection unit 60, and the like. The controller 10 and drive unit 50 are examples of a control unit U1. The controller 10, RAM 21, communication I / F 22, storage unit 23, and operation panel 24 are connected to a bus, allowing them to input and output information to and from one another.

[0027] The controller 10 includes a CPU (Central Processing Unit) 11, which is a processor, a color conversion unit 12, a halftone processing unit 13, a rasterization processing unit 14, a drive signal transmission unit 15, and the like. Based on original image data DA1 acquired from a host device HO1, a memory card (not shown), or the like, the controller 10 controls the main scanning SC1 and sub-scanning SC2 by the driving unit 50 and the ejection of droplets 37 by the recording head 30. It can be said that the controller 10 controls the driving unit 50 and the recording head 30 so that a print image IM3 corresponding to the original image data DA1 as an input image IM0 is formed on the medium ME0. The original image data DA1 may contain, for example, two colors, R (red), G (green), and B (blue), for each pixel. 8 Gradation and 2 16 RGB data having integer values ​​of gray scale can be applied. The controller 10 can be configured by a SoC (System on a Chip) or the like.

[0028] The CPU 11 is a device that centrally performs information processing and control in the printer 2. The color conversion unit 12 refers to a color conversion LUT (lookup table) that defines the correspondence between the gradation values ​​of R, G, and B and the gradation values ​​of C, M, Y, and K, and converts the RGB data into two values ​​of C, M, Y, and K for each pixel. 8 Gradation and 2 16 The ink amount data DA2 is converted into ink amount data DA2 having integer values ​​of gradation. The ink amount data DA2 represents the amounts of C, M, Y, and K liquid 36 used in pixel units. Furthermore, if the resolution of the RGB data differs from the printing resolution, the color conversion unit 12 first converts the resolution of the RGB data to the printing resolution, or converts the resolution of the ink amount data DA2 to the printing resolution.

[0029] The halftone processing unit 13 performs halftone processing using a dithering method, error diffusion method, or the like on the gradation values ​​of each pixel that make up the ink amount data DA2 to reduce the number of gradations in the gradation values ​​and generate dot data DA3. The dot data DA3 represents the formation state of dots 38 of droplets 37 on a pixel-by-pixel basis. The dot data DA3 may be binary data that represents the presence or absence of dot formation, or may be multi-value data with three or more gradations that can correspond to dots of different sizes, such as small, medium, and large dots. The rasterization processing unit 14 performs a rasterization process to rearrange the dot data DA3 in the order in which the dots 38 are formed by the driving unit 50, thereby generating raster data DA4.

[0030] The drive signal transmitter 15 generates a drive signal SG1 from the raster data DA4 and outputs it to the drive circuit 31 of the recording head 30. The drive signal SG1 corresponds to a voltage signal applied to the drive elements 32 of the recording head 30. For example, if the dot data DA3 is "dot formation," the drive signal transmitter 15 outputs a drive signal SG1 that ejects droplets for dot formation. Furthermore, if the dot data DA3 is ternary or higher-valued data, the drive signal transmitter 15 outputs a drive signal SG1 that ejects droplets for large dots if the dot data DA3 is "large dot formation," and outputs a drive signal SG1 that ejects droplets for small dots if the dot data DA3 is "small dot formation." The print image IM3 is formed on the medium ME0 in accordance with the drive signal SG1. Therefore, the ink volume data DA2, the dot data DA3, or the raster data DA4 may be applied to the input image IM0.

[0031] The above-mentioned elements (11 to 15) may be configured with an ASIC (Application Specific Integrated Circuit), and may directly read data to be processed from the RAM 21 or directly write processed data to the RAM 21.

[0032] The drive unit 50, controlled by the controller 10, includes a carriage drive unit 51 including a servo motor and a roller drive unit 55 including a servo motor. Under the control of the controller 10, the drive unit 50 reciprocates the carriage 52 along the main scanning direction D1 by driving the carriage drive unit 51, and feeds the medium ME0 along the transport path 59 in a feed direction D3 by driving the roller drive unit 55. As shown in FIG. 2, the main scanning direction D1 is a direction intersecting with the arrangement direction D4 of the nozzles 34 in the nozzle row 33, e.g., a direction perpendicular to the arrangement direction D4. In FIG. 2, the rightward direction is the forward direction D11 of the main scanning SC1, and the leftward direction is the return direction D12 of the main scanning SC1. The feed direction D3 is a direction intersecting with the main scanning direction D1, e.g., a direction perpendicular to the main scanning direction D1. In FIG. 1, the feed direction D3 is a rightward direction. The sub-scanning direction D2 shown in FIG. 2 is the opposite direction to the feed direction D3. The carriage drive unit 51 can also be said to perform a main scan that changes the relative positional relationship between the recording head 30 and the medium ME0 along the main scanning direction D1. The roller drive unit 55 includes a transport roller pair 56 and a discharge roller pair 57. Under the control of the controller 10, the roller drive unit 55 performs a sub-scan SC2 that feeds the medium ME0 in the feed direction D3 by rotating the drive transport roller of the transport roller pair 56 and the drive discharge roller of the discharge roller pair 57. The roller drive unit 55 can also be said to perform a sub-scan SC2 that changes the relative positional relationship between the medium ME0 and the recording head 30 along a sub-scanning direction D2 that intersects with the main scanning direction D1. Although the carriage 52 shown in FIG. 2 does not move in the sub-scanning direction D2, the drive unit 50 may achieve the sub-scan SC2 by moving the carriage 52 in the sub-scanning direction D2. At this time, the medium ME0 does not have to move in the sub-scanning direction D2, and the drive unit 50 may achieve the sub-scanning SC2 by moving both the carriage 52 and the medium ME0 in the sub-scanning direction D2. As shown in Figure 3, the control unit U1 completes the recording of the print image IM3 by performing main scanning SC1 in several passes. The medium ME0 is a printing substrate that holds a print image. The material of the medium ME0 is not particularly limited, and various materials such as paper, resin, metal, etc. are possible. The shape of the medium ME0 is also not particularly limited, and various shapes such as rectangular, roll-shaped, etc. are possible, and it may also be three-dimensional.

[0033] The platen 58 is located below the transport path 59 and supports the medium ME0 by contacting the medium ME0 on the transport path 59. The carriage 52 carries the recording head 30. The carriage 52 may also carry a liquid cartridge 35 that supplies the recording head 30 with liquid 36 to be ejected as droplets 37. Of course, the liquid 36 may be supplied to the recording head 30 from a liquid cartridge 35 installed outside the carriage 52 via a tube. The carriage 52 is fixed to an endless belt (not shown) and is movable in the main scanning direction D1 along an elongated guide 53 whose longitudinal direction faces the main scanning direction D1. The recording head 30, controlled by the controller 10, includes a drive circuit 31, a drive element 32, etc., and ejects droplets 37 toward the medium ME0 supported by the platen 58, thereby adhering the liquid 36 to the medium ME0. Therefore, it can be said that the control unit U1 controls the ejection of droplets 37 from the recording head 30.

[0034] The drive circuit 31 applies a voltage signal to the drive element 32 in accordance with the drive signal SG1 input from the drive signal transmission unit 15. The drive element 32 may be a piezoelectric element that applies pressure to the liquid 36 in a pressure chamber communicating with the nozzle 34, or may be a drive element that uses heat to generate bubbles in the pressure chamber and eject droplets 37 from the nozzle 34. The liquid 36 is supplied to the pressure chamber of the recording head 30 from a liquid cartridge 35. The liquid 36 in the pressure chamber is ejected as droplets 37 from the nozzle 34 toward the medium ME0 by the drive element 32. As a result, dots 38 of the droplets 37 are formed on the medium ME0, and a print image IM3 represented by a pattern of dots 38 is formed on the medium ME0. While the recording head 30 moves in the main scanning direction D1, dots 38 are formed according to the raster data DA4, and the medium ME0 is fed in the feed direction D3 by one sub-scan, and this process is repeated to form the print image IM3 on the medium ME0. Furthermore, the printer 2 may perform bidirectional printing, forming the printed image IM3 in both the forward main scan D11 and the reverse main scan D12, or may perform unidirectional printing, forming the printed image IM3 in only one of the forward main scan D11 and the reverse main scan D12.

[0035] The RAM 21 stores original image data DA1 and the like received from the host device HO1 or a memory (not shown), etc. The communication I / F 22 is connected to the host device HO1 by wire or wirelessly, and inputs and outputs information to and from the host device HO1. The host device HO1 includes computers such as personal computers and tablet terminals, mobile phones such as smartphones, digital cameras, digital video cameras, etc. The storage unit 23 may be a non-volatile semiconductor memory such as a flash memory, or a magnetic storage device such as a hard disk. The operation panel 24 includes an output unit 25 such as a liquid crystal panel that displays information, an input unit 26 such as a touch panel that accepts operations on the display screen, etc.

[0036] The detection unit 60 detects the state of the liquid 36 that has landed on the medium ME0. In particular, the detection unit 60 detects the state of the mark portion MA0 included in the intermediate image IM1. The detection unit 60 shown in FIGS. 1 and 3 is provided in the printer 2 so as not to move in the main scanning direction D1 separately from the carriage 52, and detects the density of the area where the mark portion MA0 is formed on the medium ME0 in units of a detection element such as an image sensor. The detection unit 60 may also be mounted on the carriage 52. The detection unit 60 may be a solid-state imaging element such as a line sensor or area sensor configured with CCDs (Charge Coupled Devices), as in a digital camera, or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, a CIS (Contact Image Sensor) type image sensor, or a CCD type image sensor. An external digital camera or the like may be connected to the printer 2 as the detection unit 60. The detection unit 60 of this specific example is capable of detecting the density of the pattern of dots 38 formed on the medium ME0 in units of detection elements and outputs a digital value representing the density in units of detection elements to the controller 10. The detection unit 60 is capable of detecting the state of the mark portion MA0, such as the position and density, in units of dots 38. Therefore, even if the dots 38 included in the mark portion MA0 are discretely arranged, the detection unit 60 can detect the state of the mark portion MA0.

[0037] 2 has a nozzle array 33 on a nozzle surface 30a, in which a plurality of nozzles 34 capable of ejecting droplets 37 onto medium ME0 are arranged at a predetermined nozzle pitch in an arrangement direction D4. Here, a nozzle refers to a small hole from which droplets are ejected, and a nozzle array refers to an arrangement of a plurality of nozzles. The nozzle surface 30a is an ejection surface for droplets 37. Of course, a C dot 38 is formed on medium ME0 from a C droplet 37, an M dot 38 is formed on medium ME0 from an M droplet 37, a Y dot 38 is formed on medium ME0 from a Y droplet 37, and a K dot 38 is formed on medium ME0 from a K droplet 37. The nozzle array 33 includes, for example, a C nozzle array 33C capable of ejecting C liquid 36 onto the medium ME0, an M nozzle array 33M capable of ejecting M liquid 36 onto the medium ME0, a Y nozzle array 33Y capable of ejecting Y liquid 36 onto the medium ME0, and a K nozzle array 33K capable of ejecting K liquid 36 onto the medium ME0. In each nozzle array (33C, 33M, 33Y, 33K) shown in FIG. 2, a plurality of nozzles 34 are arranged in a single row at a predetermined nozzle pitch in the arrangement direction D4. The plurality of nozzles 34 in each nozzle array (33C, 33M, 33Y, 33K) may be arranged in a staggered pattern, i.e., in two rows, at a predetermined nozzle pitch in the arrangement direction D4. Here, the arrangement direction of the plurality of nozzles 34 arranged in a staggered pattern is the direction of nozzle arrangement in each of the two rows.

[0038] As shown in FIG. 3 , the printer 2 of this example performs multiple passes over the overlap region OL1. During a midpoint pass, the printer 2 forms an intermediate image IM1 on the medium ME0 based on the input image IM0. During a subsequent pass, the printer 2 forms the remaining image IM2 on the medium ME0. The formed print image IM3 is not a test pattern for adjustments such as Bi-D adjustment, paper feed adjustment, or density adjustment, but rather an image to be printed to obtain a printout that the user wishes to use for various purposes. For example, the print image IM3 may include a natural image or photographic image that the user wishes to display or sell, or a document image to show to others, such as a line drawing for a presentation. The intermediate image IM1 is formed from the input image IM0, as exemplified above. The printer 2 includes a mark area MA0 detectable by the detection unit 60 in the intermediate image IM1. After forming the intermediate image IM1, the printer 2 fills in the area surrounding the mark area MA0 with the remaining image IM2, thereby obtaining a printout of the print image IM3 that the user wishes to use for the various purposes described above.

[0039] After forming the intermediate image IM1 and before forming the remaining image IM2, the printer 2 uses the detection unit 60 to detect the state of the mark portion MA0. When performing position adjustments such as Bi-d adjustments and paper feed adjustments, the printer 2 uses the detection unit 60 to detect the position of the mark portion MA0 as the state of the mark portion MA0. When performing density adjustments for the printed image IM3, the printer 2 uses the detection unit 60 to detect the density of the mark portion MA0 as the state of the mark portion MA0. The detected state of the mark portion MA0 is used for adjustment processes such as the position adjustments and density adjustments described above. As a result, there is no need to print a separate test pattern to adjust the printer 2. This reduces the amount of liquid and media consumed to print a test pattern, as well as the printing time.

[0040] The mark portion MA0 shown in FIG. 2 is a cross pattern in which the pattern of droplets 37 that landed on the medium ME0 intersects a main scanning line LN1 extending along the main scanning direction D1 and a sub-scanning line LN2 extending along the sub-scanning direction D2. FIG. 2 shows an example of a cross pattern in which the main scanning line LN1 and the sub-scanning line LN2 intersect at right angles. The cross pattern may be an L-shaped pattern in which the end of the main scanning line LN1 and the end of the sub-scanning line LN2 are connected, a T-shaped pattern in which the end of the sub-scanning line LN2 is connected midway through the main scanning line LN1, or a pattern in which the end of the main scanning line LN1 is connected midway through the sub-scanning line LN2. The main scanning line LN1 and the sub-scanning line LN2 may intersect without being perpendicular. The cross pattern of the mark portion MA0 allows for both Bi-d adjustment and paper feed adjustment. In the intermediate image IM1, there are no dots 38 at the landing point PO2 adjacent to the main scanning line LN1. Therefore, the density of dots 38 of the liquid 36 on the main scanning line LN1 is higher than that of the landing point PO2 adjacent to it in the sub-scanning direction D2 on the intermediate image IM1. Note that the adjacent landing point PO2 only needs to be at least one dot wide. This allows the position of the main scanning line LN1 to be detected with high accuracy. In the intermediate image IM1, there are no dots 38 at the landing point PO3 adjacent to the sub-scanning line LN2. Therefore, the density of dots 38 of the liquid 36 on the sub-scanning line LN2 is higher than that of the landing point PO3 adjacent to it in the main scanning direction D1 on the intermediate image IM1. Note that the adjacent landing point PO3 only needs to be at least one dot wide. This allows the position of the sub-scanning line LN2 to be detected with high accuracy. The landing points PO2 and PO3 are included in the landing position PO1 adjacent to the mark portion MA0.

[0041] Next, an example of bidirectional multi-pass printing will be described with reference to Figure 3. In Figure 3, the forward direction D11 of the main scanning SC1 is the rightward direction, and the return direction D12 of the main scanning SC1 is the leftward direction. Furthermore, the feed direction D3, which is the direction in which the medium ME0 moves during the sub-scanning, is the downward direction, and the sub-scanning direction D2, which is the direction in which the recording head 30 moves relative to the medium ME0, is the upward direction. Band regions B1 to B4, which are the units in which recording of the print image IM3 is completed, correspond to half the length of the nozzle row 33 in the sub-scanning direction D2. In the band regions B2 to B4, recording of the print image IM3 is completed by two passes of the main scanning SC1. At timing t1, the control unit U1 controls the main scanning SC1 to move the recording head 30 in the forward direction D11 while ejecting droplets 37 from the recording head 30 in alignment with the band areas B1 and B2. Here, for the band area B2, an intermediate image IM1 is formed in the first pass. This first pass is referred to as the first pass PA1. The band areas B1 and B2 are the areas where the image is recorded in the first pass PA1.

[0042] At the next timing t2, the control unit U1 controls the sub-scanning SC2 to move the medium ME0 along the sub-scanning direction D2 until the recording head 30 aligns with the band areas B2 and B3. Furthermore, for the band area B2, after the intermediate image IM1 is formed and before the remaining image IM2 is formed, the control unit U1 acquires the state of the mark area MA0 from the detection unit 60. At the next timing t3, the control unit U1 controls the main scanning SC1 to move the recording head 30 in the return direction D12 while ejecting droplets 37 from the recording head 30 in alignment with the band areas B2 and B3. Here, an intermediate image IM1 is formed in the first pass for the band area B3, and a printed image IM3 is formed in the second pass for the band area B2. This second pass is referred to as the second pass PA2. The band areas B2 and B3 are the recording areas of the image in the second pass PA2.

[0043] At the next timing t4, the control unit U1 controls the sub-scanning SC2 to move the medium ME0 along the sub-scanning direction D2 until the recording head 30 aligns with the band areas B3 and B4. Furthermore, for the band area B3, after the intermediate image IM1 is formed and before the remaining image IM2 is formed, the control unit U1 acquires the state of the mark area MA0 from the detection unit 60. At the next timing t5, the control unit U1 controls the main scanning SC1 to move the recording head 30 in the forward direction D11 while discharging droplets 37 from the recording head 30 in alignment with the band regions B3 and B4. Here, an intermediate image IM1 is formed in the first pass for the band region B4, and a printed image IM3 is formed in the second pass for the band region B3.

[0044] As described above, the control unit U1 controls bidirectional multi-pass printing in which a print image IM3 is formed on the medium ME0 by repeating main scanning SC1 and sub-scanning SC2. As described above, from timing t1 to t3, band area B2 becomes overlap area OL1 (see FIGS. 4 to 6) where the image printing areas of first pass PA1 and second pass PA2 overlap. From timing t3 to t5, band area B3 becomes overlap area OL1 where the image printing areas of the passes overlap. In the example shown in FIG. 3, control unit U1 performs control to form mark portion MA0 in overlap area OL1 in one pass. By forming mark portion MA0 in one pass, errors that occur in mark portion MA0 are reduced compared to when mark portion MA0 is formed in two or more passes.

[0045] First, referring to Fig. 4, an example will be described in which an input image IM0, in which dots 38 are formed at a 100% recording rate, is decomposed into individual passes to form a printed image IM3. In the schematic example shown in Fig. 4, the input image IM0 corresponds to an overlapping area OL1, and the printer 2 forms a printed image IM3 in the overlapping area OL1 in two passes, including a first pass PA1 and a second pass PA2. The second pass PA2 is the pass that follows the first pass PA1, and in the example shown in Fig. 3, it is a pass in which the direction of main scanning SC1 differs from that of the first pass PA1. The control unit U1 first decomposes the input image IM0 into an intermediate image IM1 and a remaining image IM2. Based on the input image IM0, the control unit U1 generates the intermediate image IM1 so that it includes the mark portion MA0. The dots 38 in the mark portion MA0 originate from the input image IM0. FIG. 4 shows a main scanning line LN1 in which multiple dots 38 are arranged in a main scanning direction D1, and a sub-scanning line LN2 in which multiple dots 38 are arranged in a sub-scanning direction D2. Therefore, the mark portion MA0 shown in FIG. 4 can be considered a cross pattern, which is an intersecting pattern. Furthermore, the control unit U1 does not arrange dots 38 at the landing position PO1 in the intermediate image IM1 that is adjacent to the mark portion MA0. This improves the accuracy with which the detection unit 60 detects the state of the mark portion MA0. Along with generating the intermediate image IM1, the control unit U1 generates the remaining image IM2 by removing the arrangement of dots 38 in the intermediate image IM1 from the arrangement of dots 38 in the input image IM0.

[0046] After decomposing the input image IM0, the control unit U1 controls the first pass PA1 to form an intermediate image IM1 on the medium ME0, and the second pass PA2 to form the remaining image IM2 on the medium ME0. As a result, the surrounding area including the impact position PO1 adjacent to the mark portion MA0 is filled with the remaining image IM2, completing the printed image IM3 on the medium ME0. In other words, no trace of the mark portion MA0 remains on the printed image IM3. Note that the control unit U1 can perform processing based on the state of the mark portion MA0 by obtaining the state of the mark portion MA0 from the detection unit 60 before forming the remaining image IM2.

[0047] The recording rate of dots 38 in print image IM3 may be less than 100%. FIG. 5 shows, as an example, how print image IM3 is formed by decomposing input image IM0, in which dots 38 are formed at a 50% recording rate, for each pass. In this case, too, the control unit U1 decomposes input image IM0 into intermediate image IM1 and remaining image IM2. As a result, the dots 38 in mark portion MA0 are arranged discretely. FIG. 5 shows a main scan line LN1 in which multiple dots 38 are arranged discretely in the main scanning direction D1, and a sub-scan line LN2 in which multiple dots 38 are arranged discretely in the sub-scanning direction D2. Again, the control unit U1 does not arrange dots 38 at landing position PO1 adjacent to mark portion MA0 in intermediate image IM1. Therefore, mark portion MA0 has a higher density of dots 38 than the adjacent landing position PO1 in intermediate image IM1, making it detectable by the detection unit 60. Of course, in conjunction with the generation of the intermediate image IM1, the control unit U1 generates the remaining image IM2 by removing the arrangement of the dots 38 in the intermediate image IM1 from the arrangement of the dots 38 in the input image IM0. After decomposing the input image IM0, the control unit U1 controls the first pass PA1 to form an intermediate image IM1 on the medium ME0, and controls the second pass PA2 to form the remaining image IM2 on the medium ME0. As a result, the surrounding area including the impact position PO1 adjacent to the mark portion MA0 is filled with the remaining image IM2, and a printed image IM3 is completed on the medium ME0.

[0048] When the recording head 30 moves in the opposite direction in the second pass PA2 to that in the first pass PA1, the area surrounding the mark portion MA0 in the overlap area OL1 is filled with dots 38 in which the recording head 30 moves in the opposite direction to that in the mark portion MA0, as shown in FIG. 6. In the schematic example shown in FIG. 6, the recording head 30 has nozzles 34 #0 to #9 as a nozzle array 33, and the sub-scanning direction D2 is the upward direction. Of course, the nozzle array 33 may include 11 or more nozzles 34. Although the recording head 30 shown in FIGS. 1 and 3 does not move in the sub-scanning direction D2, FIG. 6 shows the relative position of the recording head 30 with respect to the medium ME0, which moves in the feed direction D3 in the first pass PA1 and the second pass PA2. If the sub-scanning direction D2 is the direction of movement of the recording head 30 relative to the medium ME0, the upstream side with respect to the sub-scanning direction D2 is the lower side, and the downstream side with respect to the sub-scanning direction D2 is the upper side. In the first pass PA1, a main scan SC1 is performed in which the recording head 30 moves in the forward direction D11, and dots 38 can be formed at the locations indicated by circle 1. In the second pass PA2, a main scan SC1 is performed in which the recording head 30 moves in the backward direction D12, and dots 38 can be formed at the locations indicated by circle 2.

[0049] Raster lines RL1 to RL5 extending along the main scanning direction D1 are shown in the overlapping area OL1 shown in Fig. 6. The combinations of nozzles 34 used for each raster line are shown at the bottom of Fig. 6. The combination of nozzles 34 that eject droplets 37 onto raster line RL1 is nozzle #5, which is used during first pass PA1, and nozzle #0, which is used during second pass PA2. Nozzle #5 is used to form intermediate image IM1, which includes mark portion MA0, and nozzle #0 is used to form the remaining image IM2. Therefore, for raster line RL1, nozzle #5, which is the most downstream of nozzles #5 and #0 in the sub-scanning direction D2, is used as downstream nozzle NZ1 to form mark portion MA0.

[0050] The combination of nozzles 34 that eject droplets 37 onto raster line RL2 is nozzle #6, which is used during first pass PA1, and nozzle #1, which is used during second pass PA2. Therefore, the downstream nozzle NZ1 on raster line RL2 is nozzle #6. The combination of nozzles 34 that eject droplets 37 onto raster line RL3 is nozzle #7, which is used during first pass PA1, and nozzle #2, which is used during second pass PA2. Therefore, the downstream nozzle NZ1 on raster line RL3 is nozzle #7. The combination of nozzles 34 that eject droplets 37 onto raster line RL4 is nozzle #8, which is used during first pass PA1, and nozzle #3, which is used during second pass PA2. Therefore, the downstream nozzle NZ1 on raster line RL4 is nozzle #8. The combination of nozzles 34 that eject droplets 37 onto raster line RL5 is nozzle #9, which is used during first pass PA1, and nozzle #4, which is used during second pass PA2. Therefore, the downstream nozzle NZ1 on raster line RL5 is nozzle #9.

[0051] As described above, the control unit U1 controls the formation of the mark portion MA0 in the overlap region OL1 by ejecting the liquid 36 from the downstream nozzle NZ1 among the combination of the multiple nozzles 34 that eject the liquid 36 onto each raster line in the overlap region OL1. By forming the mark portion MA0 by the liquid 36 ejected from the downstream nozzle NZ1 onto the overlap region OL1, the state of the mark portion MA0 that is not affected by the liquid 36 ejected onto the overlap region OL1 from the other nozzles is detected by the detection unit 60. Therefore, the mark portion MA0 is detected with high accuracy.

[0052] Furthermore, in the remaining image IM2, at least the portion of the raster line RL2-RL4 that is the same as the mark portion MA0 is formed by droplets 37 landing in the second pass PA2, in which the movement direction of the recording head 30 is opposite to that of the first pass PA1, to form dots 38. Therefore, the control unit U1 controls the second pass PA2 to form on the medium ME0 at least the portion of the remaining image IM2 that is the same as the raster line RL2-RL4 as the mark portion MA0. This makes it difficult for the characteristics of the raster lines RL2-RL4 that are the same as the mark portion MA0 to appear, and makes it possible to prevent traces of the mark portion MA0 from remaining when the printed image is completed.

[0053] (3) Examples of adjustment processes: FIG. 7 shows a schematic example of the adjustment process of the printer 2. The adjustment process is performed, for example, by the controller 10 serving as the control unit U1 shown in FIG. 1. Here, steps S102 to S104 correspond to the intermediate image forming process ST1, step S106 corresponds to the detection process ST2, step S108 corresponds to the residual image forming process ST3, and step S110 corresponds to the processing process ST4. Hereinafter, the word "step" may be omitted, and the step number may be shown in parentheses. The print control process of S102 to S108 begins when the controller 10 receives a print instruction to form a print image IM3 that is not a test pattern for adjustment. The print instruction may be an instruction resulting from a print request from the host device HO1 to the printer 2, or an instruction resulting from a print start operation to the input unit 26 of the printer 2. The adjustment in S110 may be triggered by the print control processing in S102 to S108, or may be performed at predetermined intervals such as once a month independently of the print control processing, or may be performed when an adjustment instruction is received by the controller 10. The adjustment instruction may be an instruction resulting from an adjustment request from the host device HO1 to the printer 2, or an instruction resulting from an adjustment start operation on the input unit 26 of the printer 2. The adjustment process will be described below with reference to FIGS.

[0054] When the adjustment process begins, the controller 10 decomposes the input image IM0 into an intermediate image IM1 and a remaining image IM2 (S102). First, the controller 10 generates the intermediate image IM1 based on the input image IM0 so that it includes a mark portion MA0 that can be detected by the detection unit 60. The controller 10 may generate the intermediate image IM1 so that dots 38 are not placed at the landing position PO1 adjacent to the mark portion MA0 in the intermediate image IM1. This prevents the recording head 30 from ejecting the liquid 36 at the adjacent landing position PO1 when the mark portion MA0 is formed in the first pass PA1. Note that as long as the state of the mark portion MA0 is detectable by the detection unit 60, dots 38 may be placed at the adjacent landing position PO1. Next, the controller 10 generates the remaining image IM2 by removing the arrangement of dots 38 in the intermediate image IM1 from the arrangement of dots 38 in the input image IM0.

[0055] After decomposing the input image IM0, the controller 10 controls the recording head 30 and the drive unit 50 to form an intermediate image IM1 including the mark portion MA0 in the overlap region OL1 during a pass, such as the first pass PA1, among multiple passes (S104). For example, the controller 10 moves the recording head 30 in the forward direction D11 while ejecting droplets 37 from the recording head 30 in alignment with the band region B1 and the band region B2 serving as the overlap region OL1, as shown at timing t1 in FIG. 3. When droplets 37 ejected from the recording head 30 during the main scan SC1 land on the medium ME0, the controller 10 controls the sub-scan SC2 so that droplets 37 are ejected from the recording head 30 in the overlap region OL1 during a subsequent pass, such as the second pass PA2. For example, the controller 10 controls the sub-scan SC2 to move the medium ME0 along the sub-scan direction D2 until the recording head 30 aligns with the band regions B2 and B3, as shown at timing t2 in FIG. 3. In this manner, the control unit U1 performs control to form the intermediate image IM1 including the mark portion MA0 on the medium ME0 based on the input image IM0 in an intermediate pass.

[0056] After the mark portion MA0 is formed, the detection unit 60 detects the state of the mark portion MA0 by capturing an image of the mark portion MA0 and its vicinity. The control unit U1 acquires the state of the mark portion MA0 from the detection unit 60. For example, if the mark portion MA0 has a cross pattern as shown in FIG. 2, the controller 10 acquires the position of the main scanning line LN1 in the sub-scanning direction D2 and the position of the sub-scanning line LN2 in the main scanning direction D1 from the detection unit 60 (S106). When the detection unit 60 outputs the captured image to the controller 10, the controller 10 first extracts the mark portion MA0 from the captured image acquired from the detection unit 60. The controller 10 can then determine the position of the main scanning line LN1 in the sub-scanning direction D2 and the position of the sub-scanning line LN2 in the main scanning direction D1 based on the captured image. Depending on the input image IM0, the mark portion MA0 may not be detected from the overlapping area OL1. In this case, the controller 10 may obtain the state of the mark portion MA0 from the detection unit 60 in the next or subsequent pass.

[0057] After acquiring the state of the mark portion MA0, the controller 10 controls the recording head 30 and the drive unit 50 to form the remaining image IM2 in the overlap region OL1 in a subsequent pass, for example, the second pass PA2 (S108). For example, as shown in FIG. 3, the controller 10 moves the recording head 30 in the return direction D12 while ejecting droplets 37 from the recording head 30 in accordance with the band region B2 and band region B3 that form the overlap region OL1, as shown at timing t3. As a result, the surrounding area including the impact position PO1 adjacent to the mark portion MA0 is filled with the remaining image IM2, completing the recording of the print image IM3 in the overlap region OL1. The controller 10 repeatedly controls the recording of the print image IM3 in the overlap area OL1 while repeating the main scanning SC1 and the sub-scanning SC2.

[0058] Thereafter, at the timing of adjustment, the controller 10 performs adjustment based on the state of the mark portion MA0 (S110) and ends the adjustment process. The adjustment based on the state of the mark portion MA0 includes Bi-d adjustment, PF adjustment (paper feed adjustment), density adjustment, etc., as exemplified in FIG.

[0059] FIG. 8 shows a schematic example of adjustment based on the state of the mark portion MA0. Bi-d adjustment refers to setting an adjustment value V1 to align the landing positions of droplets 37 on the forward pass with the landing positions of droplets 37 on the backward pass in the main scanning direction D1. Here, the forward pass refers to the main scanning SC1 in which the recording head 30 moves in the forward direction D11, and the backward pass refers to the main scanning SC1 in which the recording head 30 moves in the backward direction D12. For example, as shown in FIG. 8, the landing positions on the backward pass that should be aligned with the landing positions on the forward pass in the main scanning direction D1 are shifted in the forward direction D11 from the landing positions on the forward pass. In this case, the position of the sub-scanning line LN2 formed on the medium ME0 on the backward pass is shifted in the forward direction D11 from the position of the sub-scanning line LN2 formed on the medium ME0 on the forward pass. The controller 10 can perform Bi-d adjustment by storing an adjustment value V1 corresponding to the positional deviation of the sub-scanning line LN2 in the memory unit 23 of the printer 2. For example, the controller 10 can align the landing positions of the droplets 37 in the main scanning direction D1 between the forward and backward passes by delaying the ejection timing of the droplets 37 from the recording head 30 on the backward pass in accordance with the adjustment value V1. Of course, even if the landing positions on the backward pass that should be aligned with the landing positions on the forward pass in the main scanning direction D1 are shifted in the backward direction D12 from the landing positions on the forward pass, the landing positions of the droplets 37 in the main scanning direction D1 between the forward and backward passes can be aligned by setting the adjustment value V1. Note that the mark portion MA0 suitable for Bi-d adjustment only needs to have the sub-scanning line LN2, and does not necessarily need to have the main scanning line LN1. However, even if the mark portion MA0 does not have the sub-scanning line LN2, the position of the mark portion MA0 in the main scanning direction D1 can be detected, and therefore Bi-d adjustment can be performed.

[0060] PF adjustment refers to setting an adjustment value V2 to ensure that the transport amount of the medium ME0 during the sub-scanning SC2 in the sub-scanning direction D2 is neither too large nor too small. If the transport amount of the medium ME0 during the sub-scanning SC2 is too large, gaps between band regions, such as light streaks, appear. If the transport amount of the medium ME0 during the sub-scanning SC2 is too small, overlapping dots 38 between band regions, such as dark streaks, appear. Therefore, the controller 10 stores the adjustment value V2 in the memory unit 23 and performs PF adjustment based on the adjustment value V2. For example, as shown in FIG. 8, the spacing between the landing positions of droplets 37 between sub-scanning SC2 in the sub-scanning direction D2 is assumed to be wider than the designed width WB of the band region. In this case, the spacing between the main scan line LN1 formed on the medium ME0 in a certain pass and the main scan line LN1 formed on the medium ME0 in the previous pass is wider than the width WB of the band region. The controller 10 can perform PF adjustment by storing an adjustment value V2, which corresponds to the deviation in the spacing between the main scan lines LN1 relative to the width WB of the band area, in the memory unit 23 of the printer 2. For example, the controller 10 can adjust the transport amount of the medium ME0 during the sub-scan SC2 in the sub-scanning direction D2 so that it is neither too much nor too little, by reducing the transport amount of the medium ME0 during the sub-scan SC2 in accordance with the adjustment value V2. Of course, even if the distance between the landing positions of the droplets 37 between the sub-scans SC2 in the sub-scanning direction D2 is narrower than the designed width WB of the band area, the setting of the adjustment value V2 can adjust the transport amount of the medium ME0 during the sub-scan SC2 so that it is neither too much nor too little. Note that the mark portion MA0 suitable for PF adjustment only needs to have the main scanning line LN1, and does not necessarily need to have the sub-scanning line LN2. However, even if the mark portion MA0 does not have the main scanning line LN1, the position of the mark portion MA0 in the sub-scanning direction D2 can be detected, and therefore PF adjustment can be performed.

[0061] Density adjustment refers to setting an adjustment value V3 to match the density of the print image IM3 to the density of the input image IM0. The mark area MA0 for density adjustment is preferably a two-dimensional image, such as a rectangle as shown in FIG. 8, so that the density can be detected accurately. For example, as shown in FIG. 8, the print image IM3 is assumed to be darker than the input image IM0. In this case, the output density of the mark area MA0 is darker than the density of the mark area data DAm used to form the mark area MA0. The controller 10 can perform density adjustment by storing an adjustment value V3 corresponding to the deviation of the output density of the mark area MA0 from the density of the mark area data DAm in the memory unit 23 of the printer 2. For example, the controller 10 can match the density of the print image IM3 to the density of the input image IM0 by lightening the output density of the mark area MA0 corresponding to the mark area data DAm to the density of the mark area data DAm in accordance with the adjustment value V3. Of course, even if the print image IM3 is lighter than the input image IM0, the density of the print image IM3 can be adjusted to match the density of the input image IM0 by setting the adjustment value V3.

[0062] As described above, the state of the mark portion MA0 included in the intermediate image IM1 formed in an intermediate pass is detected, and the remaining image IM2 formed in a later pass erases the traces of the mark portion MA0 to form a printed image IM3. While the printed image IM3, which is not a test pattern, is formed, processing based on the state of the mark portion MA0, such as Bi-d adjustment, paper feed adjustment, and density adjustment, is performed. In this way, there is no need to print a separate test pattern to adjust the printer 2. Therefore, this example can reduce the amount of liquid and media consumed and the printing time required to print the test pattern.

[0063] (4) Variation: The present invention can be modified in various ways. For example, the color combination of the liquid 36 is not limited to C, M, Y, and K, and may include, in addition to C, M, Y, and K, orange, green, light cyan with a lower density than C, light magenta with a lower density than M, dark yellow with a higher density than Y, light black with a lower density than K, colorless for improving image quality, etc. Also, some of the colors C, M, Y, and K in the color combination of the liquid 36 may be absent. The entity that performs the above-described processing is not limited to a CPU, but may be an electronic component other than a CPU, such as an ASIC, etc. Of course, multiple CPUs may work together to perform the above-described processing, or a CPU and another electronic component (for example, an ASIC) may work together to perform the above-described processing. Some of the above-described processing may be performed by the host device HO1. In this case, the combination of the controller 10, drive unit 50, and host device HO1 is an example of a control unit U1, and the combination of the printer 2 and host device HO1 is an example of a printing device 1. The movement direction of the recording head 30 in the second pass PA2 may be the same as the movement direction of the recording head 30 in the first pass PA1. In this case, the movement direction of the recording head 30 in both passes (PA1, PA2) may be the forward direction D11 or the backward direction D12.

[0064] As shown in Fig. 9, the print image IM3 in the overlap area OL1 may be recorded in three or more passes. Pass decomposition examples DC1 and DC2 shown in Fig. 9 illustrate an example in which the input image IM0 shown in Figs. 4 and 5 is decomposed into a first pass PA1, a second pass PA2 following the first pass PA1, and a third pass PA3 following the second pass PA2. The controller 10 may perform a main scan SC1 in the forward direction D11 in the first pass PA1, a main scan SC1 in the reverse direction D12 in the second pass PA2, and a main scan SC1 in the forward direction D11 in the third pass PA3.

[0065] Pass decomposition example DC1 shows that an intermediate image IM1 including a mark portion MA0 is formed in a first pass PA1, which is an intermediate pass, and the remaining image IM2 is formed in subsequent passes (PA2, PA3). The controller 10 controls the first pass PA1 to form the intermediate image IM1 on the medium ME0 based on the input image IM0, and the second pass PA2 and the third pass PA3 to form the remaining image IM2 on the medium ME0. Therefore, the controller 10 can be said to form the mark portion MA0 in the overlap region OL1 in the first pass, or to form the mark portion MA0 in the overlap region OL1 in one pass. The controller 10 only needs to acquire the state of the mark portion MA0 detected by the detection unit 60 after the mark portion MA0 is formed in the first pass PA1 and before the second pass PA2 is performed. FIG. 9 shows that a trace of the mark portion MA0 remains after the second pass PA2 and before the third pass PA3 is performed. Therefore, the controller 10 can also acquire the state of the mark portion MA0 detected by the detection unit 60 after the second pass PA2 and before the third pass PA3 is performed. Of course, even if the number of passes is four or more, the print image IM3 can be formed in the same manner.

[0066] Pass decomposition example DC2 shows that an intermediate image IM1 is formed in an intermediate pass (PA1, PA2), a mark portion MA0 is formed in the second pass PA2, and the remaining image IM2 is formed in the subsequent third pass PA3. The controller 10 performs control so that the intermediate image IM1 is formed on the medium ME0 based on the input image IM0 in the intermediate passes (PA1, PA2), and the mark portion MA0 is formed on the medium ME0 in the second pass PA2. Therefore, it can be said that the controller 10 forms the mark portion MA0 in the overlap region OL1 in a single pass. After the intermediate image IM1 is formed, the controller 10 performs control so that the remaining image IM2 is formed on the medium ME0 in the third pass PA3. The controller 10 only needs to acquire the state of the mark portion MA0 detected by the detection unit 60 after the mark portion MA0 is formed in the second pass PA2 and before the third pass PA3 is performed. Of course, even if the number of passes is four or more, the print image IM3 can be formed in the same manner.

[0067] As shown in Fig. 10, even when the printing of the print image IM3 in the band areas B1 to B3 that are not the overlapping area OL1 is performed in one pass, the formation of the mark portion MA0 in the overlapping area OL1 makes it possible to perform adjustments such as PF adjustment. Fig. 10 shows a schematic example of partial overlap printing, in which the printing areas of the print images IM3 for each pass are partially overlapped in so-called band printing. In a first pass PA1 shown in FIG. 10 , the controller 10 controls the main scanning SC1 to move the recording head 30 in the forward direction D11 while ejecting droplets 37 from the recording head 30 in alignment with the band region B1 and the overlapping regions OL1 on both sides. Here, the usage rate of the nozzles 34 in the band region B1 is 100%, and the usage rate of the nozzles 34 in the overlapping region OL1 is 50%. In a subsequent second pass PA2, the controller 10 controls the main scanning SC1 to move the recording head 30 in the backward direction D12 while ejecting droplets 37 from the recording head 30 in alignment with the band region B1 and the overlapping regions OL1 on both sides. Here, the usage rate of the nozzles 34 in the band region B2 is 100%, and the usage rate of the nozzles 34 in the overlapping region OL1 is 50%. In the subsequent pass, the controller 10 controls the main scanning SC1 to move the recording head 30 in the forward direction D11 while ejecting droplets 37 from the recording head 30 in alignment with the band region B3 and the overlapping regions OL1 on both sides. Here, the usage rate of the nozzles 34 in the band region B3 is 100%, and the usage rate of the nozzles 34 in the overlap region OL1 is 50%. In this way, the control unit U1 controls partial overlap printing by repeating main scanning SC1 and sub-scanning SC2.

[0068] FIG. 11 is a schematic diagram illustrating the dot arrangement until the print image IM3 is formed in the overlapping area OL1 shown in FIG. The controller 10 first separates the input image IM0 into an intermediate image IM1 and a remaining image IM2. The mark portion MA0 shown in FIG. 11 is a main scanning line LN1 aligned in the main scanning direction D1 and located at the downstream end of the overlapping area OL1 in the sub-scanning direction D2. The controller 10 does not place dots 38 at the landing position PO2 of the intermediate image IM1 adjacent to the main scanning line LN1 in the sub-scanning direction D2. This allows the detection unit 60 to accurately detect the state of the mark portion MA0. After separating the input image IM0, the controller 10 controls the first pass PA1 to form the intermediate image IM1 on the medium ME0, and the second pass PA2 to form the remaining image IM2 on the medium ME0. As a result, the surrounding area including the landing position PO1 adjacent to the mark portion MA0 is filled with the remaining image IM2, completing the printed image IM3 on the medium ME0. When the second pass PA2 has the opposite movement direction of the recording head 30 to that of the first pass PA1, as shown in Figure 12, the area surrounding the mark portion MA0 in the overlap area OL1 is filled with dots 38 whose movement direction of the recording head 30 is opposite to that of the mark portion MA0.

[0069] Raster lines RL1 to RL4 along the main scanning direction D1 are shown in the overlapping area OL1 shown in Fig. 12. The combinations of nozzles 34 used for each raster line are shown at the bottom of Fig. 12. The combination of nozzles 34 that eject droplets 37 onto raster line RL1 is nozzle #6, which is used during first pass PA1, and nozzle #0, which is used during second pass PA2. Nozzle #6 is used to form intermediate image IM1, including mark portion MA0, and nozzle #0 is used to form the remaining image IM2. Therefore, for raster line RL1, nozzle #5, which is the most downstream of nozzles #6 and #0 in the sub-scanning direction D2, is used as downstream nozzle NZ1 to form mark portion MA0. Similarly, the downstream nozzles NZ1 for raster lines RL2, RL3, and RL4 are nozzles #7, #8, and #9, respectively.

[0070] 12, the multiple nozzles 34 that eject droplets 37 into the overlap region OL1 are nozzles #0 to #3 and #6 to #9. Of these nozzles, nozzle #9, which is the most downstream nozzle in the sub-scanning direction D2, is designated the most downstream nozzle NZ2. The mark portion MA0 is formed in the first pass PA1 at the most downstream side of the overlap region OL1 in the sub-scanning direction D2 by ejecting droplets 37 from nozzle #9, which is the most downstream nozzle NZ2. That is, the control unit U1 performs control to form the mark portion MA0 in the overlap region OL1 by ejecting the liquid 36 from the most downstream nozzle NZ2 of the multiple nozzles 34 that eject the liquid 36 into the overlap region OL1. Because droplets 37 are ejected first from the most downstream nozzle NZ2 onto the overlap region OL1, the detection unit 60 detects the state of the mark portion MA0, which is not affected by droplets 37 ejected onto the overlap region OL1 from nozzles 34 other than the most downstream nozzle NZ2. Furthermore, because the most downstream nozzle NZ2 is located furthest downstream in the nozzle row 33, no dots 38 are formed downstream in the sub-scanning direction D2 before the mark portion MA0 is formed, and the detection unit 60 detects the state of the mark portion MA0, which is not affected by the dots 38. If the most downstream nozzle NZ2 is set as the nozzle for forming the mark portion, the mark portion MA0 will be formed regardless of what type of recording is performed, so there is no need for processing or memory area to determine the nozzle for forming the mark portion.

[0071] As shown in FIG. 13, even if the transport amount of the medium ME0 during sub-scan SC2 is not an integer multiple of the nozzle pitch, the downstream nozzles NZ1, including the most downstream nozzle NZ2, can be set as nozzles for forming the mark portion. FIG. 13 schematically illustrates a combination of nozzles 34 used for each raster line in the overlap area OL1 when the medium transport amount during sub-scan SC2 is 1.25 times the nozzle pitch. In the schematic example shown in FIG. 13, the recording head 30 has nozzles 34 #0 to #9 as a nozzle row 33, and the sub-scanning direction D2 is the upward direction. FIG. 13 shows the relative position of the recording head 30 with respect to the medium ME0 moving in the feed direction D3 during each pass.

[0072] The nozzle pitch of the nozzle array of the print head 30 shown in FIG. 13 is four dots. If the print head 30 moves relatively in the sub-scanning direction D2 by 1.25 times the nozzle pitch each time a sub-scan SC2 is performed, the relative movement of the print head 30 during the sub-scan is equivalent to five dots. As shown in FIG. 13, when the first pass PA1 and the second pass PA2 are performed, an overlapping area OL1 including raster lines RL1 to RL5 is generated. Here, for raster line RL1, nozzle #0 is used after nozzle #5; for raster line RL2, nozzle #4 is used after nozzle #9; for raster line RL3, nozzle #3 is used after nozzle #8; for raster line RL4, nozzle #2 is used after nozzle #7; and for raster line RL5, nozzle #1 is used after nozzle #6. Therefore, the downstream nozzles NZ1 for forming the mark portion MA0 are nozzles #5 to #9, and the most downstream nozzle NZ2 is nozzle #9. Here again, the mark portion MA0 is formed by the liquid 36 ejected from the downstream nozzle NZ1 onto the overlap region OL1, allowing the detection unit 60 to detect the state of the mark portion MA0, which is not affected by the liquid 36 ejected from the other nozzles onto the overlap region OL1. Because droplets 37 are ejected from the most downstream nozzle NZ2 onto the overlap region OL1 first, the detection unit 60 detects the state of the mark portion MA0, which is not affected by droplets 37 ejected from the nozzles 34 other than the most downstream nozzle NZ2 onto the overlap region OL1. Furthermore, because the most downstream nozzle NZ2 is located furthest downstream in the nozzle row 33, no dots 38 are formed downstream in the sub-scanning direction D2 before the mark portion MA0 is formed, and the detection unit 60 detects the state of the mark portion MA0, which is not affected by the dots 38. Therefore, the state of the mark portion MA0 is detected with high accuracy, and by setting the most downstream nozzle NZ2 as the nozzle for forming the mark portion, there is no need for processing or memory storage for determining the nozzle for forming the mark portion.

[0073] As shown in Figure 14, even when a print image IM3 is formed in multiple multi-pass areas (MP1, MP2) that have different numbers of passes to complete the recording of the print image IM3, processing based on the state of the mark portion MA0 can be performed. Figure 14 schematically illustrates a combination of nozzles 34 when a first multi-pass area MP1 and a second multi-pass area MP2 are formed. In the schematic example shown in Figure 14, the print head 30 has nozzles 34 n1 to n6 as a nozzle row 33, and the sub-scanning direction D2 is upward. Figure 14 shows the relative position of the print head 30 with respect to the medium ME0 moving in the feed direction D3 in each pass.

[0074] The print head 30 shown in FIG. 14 has an upstream nozzle array including nozzles 34 n1 to n3, and a downstream nozzle array including nozzles 34 n4 to n6. The upstream nozzle array includes multiple upstream end nozzles designated n1, multiple normal nozzles designated n2, and multiple downstream end nozzles designated n3. The downstream nozzle array includes multiple upstream end nozzles designated n4, multiple normal nozzles designated n5, and multiple downstream end nozzles designated n6. In the example shown in FIG. 14, the number of normal nozzles n2 and n5 is 7, and the number of end nozzles n1, n3, n4, and n6 is 2. The relative movement amount of the print head 30 during sub-scanning is 9 nozzles. In band regions B1, B4, and B7 where the normal nozzles n5 and n2 are combined, the usage rates of the normal nozzles n5 and n2 are each 50%. For band regions B2 and B5, which combine nozzles n5, n3, and n1, the usage rate of the normal nozzle n5 is 50%, and the usage rates of the end nozzles n3 and n1 are each 25%. For band regions B3 and B6, which combine nozzles n6, n4, and n2, the usage rate of the normal nozzle n2 is 50%, and the usage rates of the end nozzles n6 and n4 are each 25%. Figure 14 shows the first pass PA1 and second pass PA2 when band region B4 is fitted into overlap region OL1.

[0075] As shown in FIG. 14, band areas B1, B4, and B7 become a first multi-pass area MP1 in which recording of print image IM3 is completed in two passes. In this case, the predetermined number of passes is two. Band areas B2, B3, B5, and B6 become a second multi-pass area MP2 in which recording of print image IM3 is completed in three passes (more than two passes). Control unit U1 completes recording of print image IM3 in the sub-scanning direction D2 so that there is a first multi-pass area MP1 in which recording is performed with a predetermined number of passes, which is two or more, and a second multi-pass area MP2 in which recording is performed with a number of passes greater than the predetermined number. Then, control unit U1 controls the formation of mark area MA0 in first multi-pass area MP1.

[0076] Fig. 15 shows a schematic example of the combinations of nozzles 34 used for each raster line of the first multi-pass region MP1. The overlapping region OL1 shown in Fig. 15 is, for example, the band region B4, which is one of the first multi-pass regions MP1 shown in Fig. 14. The overlapping region OL1 shown in Fig. 15 shows raster lines RL1 to RL5 along the main scanning direction D1. The lower part of Fig. 15 shows the combinations of nozzles 34 used for each raster line. The combination of nozzles 34 that eject droplets 37 onto raster lines RL1 to RL5 is always a combination of nozzle n5 used during the first pass PA1 and nozzle n2 used during the second pass PA2. Nozzle n5 is used to form intermediate image IM1, which includes mark portion MA0, and nozzle n2 is used to form the remaining image IM2. Therefore, of nozzles n5 and n2, nozzle n5, which is furthest downstream in the sub-scanning direction D2, is used as downstream nozzle NZ1 to form mark portion MA0.

[0077] Because the mark portion MA0 is formed with a small number of passes, if the mark portion MA0 is formed in the second multi-pass area MP2, which has a relatively large number of passes, there will be a relatively large difference in recording characteristics between the mark portion MA0 and its surroundings, and the mark portion MA0 may stand out in the printed image IM3. In the example shown in Figure 15, the mark portion MA0 is formed in the first multi-pass area MP1, which has a relatively small number of passes, so it is possible to make the mark portion MA0 less noticeable in the printed image IM3.

[0078] (5) Conclusion: As described above, the present invention can provide various configurations that can reduce the amount of liquid consumed, the amount of media consumed, and the printing time required to print a test pattern. Of course, even in an embodiment that includes only the elements of the independent claims, the basic functions and effects described above can be achieved. Furthermore, it is possible to implement configurations in which the components disclosed in the above examples are substituted with each other or the combination is changed, or configurations in which the components disclosed in the publicly known techniques and the above examples are substituted with each other or the combination is changed, etc. The present invention also includes these configurations. [Explanation of symbols]

[0079] 1...printing device, 2...printer, 10...controller, 30...recording head, 33...nozzle row, 34...nozzle, 36...liquid, 37...droplet, 38...dot, 50...drive unit, 52...carriage, 60...detection unit, B1 to B7...band area, D1...main scanning direction, D2...sub-scanning direction, D3...feed direction, D4...arrangement direction, D11...forward direction, D12...return direction, DC1, DC2...path decomposition example, HO1...host device, IM0...input image, IM1...intermediate image, IM2...remaining image, IM3...printed image, LN1...main scanning line, LN2...sub-scan Inspection line, MA0...mark portion, ME0...medium, MP1...first multi-pass area, MP2...second multi-pass area, NZ1...downstream nozzle, NZ2...most downstream nozzle, OL1...overlapping area, PA1...first pass, PA2...second pass, PA3...third pass, PO1, PO2, PO3...adjacent impact positions, RL1 to RL5...raster line, SC1...main scanning, SC2...sub-scanning, ST1...intermediate image formation process, ST2...detection process, ST3...residual image formation process, ST4...processing process, U1...controller, V1 to V3...adjustment value, WB...width of band area.

Claims

1. A printing device that forms a print image corresponding to an input image on a medium, a recording head having a nozzle array capable of ejecting liquid onto the medium; a control unit that controls a main scan that changes the relative positional relationship between the recording head and the medium along a main scan direction, a sub-scan that changes the relative positional relationship between the medium and the recording head along a sub-scan direction that intersects the main scan direction, and the ejection of the liquid from the recording head, and completes recording of the print image by the main scan in multiple passes; a detection unit that detects the state of the liquid that has landed on the medium, The control unit performing control to form an intermediate image including a mark portion detectable by the detection unit on the medium based on the input image in a middle pass among the plurality of passes; performing control to form the remaining images of the print image, excluding the intermediate image, on the medium in a pass subsequent to the intermediate pass; the detection unit detects the state of the mark unit, The control unit is capable of executing a process based on the state of the mark unit detected by the detection unit.

2. the plurality of passes includes a first pass and a second pass; The control unit controlling the formation of the print image so that an overlapping area occurs between a recording area of ​​the image in the first pass and a recording area of ​​the image in the second pass; The printing apparatus according to claim 1 , wherein the printing apparatus performs control such that the mark portion is formed in the overlapping region in one pass.

3. the plurality of passes includes a first pass and a second pass; The control unit controlling the formation of the print image so that an overlapping area occurs between a recording area of ​​the image in the first pass and a recording area of ​​the image in the second pass; 3. A printing device according to claim 1, wherein the sub-scanning direction is the relative movement direction of the recording head with respect to the medium, and control is performed to form the mark portion in the overlapping region by ejecting the liquid from a downstream nozzle that is furthest downstream in the sub-scanning direction among a combination of multiple nozzles that eject the liquid onto a raster line along the main scanning direction in the overlapping region.

4. the plurality of passes includes a first pass and a second pass; The control unit controlling the formation of the print image so that an overlapping area occurs between a recording area of ​​the image in the first pass and a recording area of ​​the image in the second pass; 3. A printing device as described in claim 1 or claim 2, wherein the sub-scanning direction is the relative movement direction of the recording head with respect to the medium, and control is performed to form the mark portion in the overlapping area by ejecting the liquid from the nozzle that is furthest downstream in the sub-scanning direction among multiple nozzles that eject the liquid into the overlapping area.

5. the plurality of passes includes a first pass and a second pass in which the recording head moves in a direction opposite to the first pass; The control unit controlling the formation of the intermediate image on the medium in the first pass; 3. The printing device according to claim 1, wherein control is performed to form on the medium in the second pass at least a portion of the remaining image that is on the same raster line as the mark portion and that is along the main scanning direction.

6. The control unit completing the recording so that there is a first multi-pass area in which the recording is completed in a predetermined number of passes, which is equal to or greater than two, and a second multi-pass area in which the recording is completed in a number of passes greater than the predetermined number of passes in the sub-scanning direction; The printing apparatus according to claim 1 or 2, wherein control is performed to form the mark portion in the first multi-pass area.

7. 3. The printing device according to claim 1, wherein the control unit prevents the liquid from being ejected from the recording head at a landing position on the medium adjacent to the mark portion when the mark portion is formed in the intermediate pass.

8. the mark portion is a cross pattern in which a main scanning line extending along the main scanning direction and a sub-scanning line extending along the sub-scanning direction intersect with each other, the pattern of the liquid having landed on the medium being a cross pattern, the main scanning line has a higher density of liquid dots than adjacent landing locations in the sub-scanning direction in the intermediate image; 3. The printing device according to claim 1, wherein the density of the liquid dots in the sub-scanning line is higher than that of adjacent landing locations in the main scanning direction in the intermediate image.

9. A control method for a printing device that performs a main scan that changes a relative positional relationship between a medium and a recording head having a nozzle array capable of ejecting liquid onto the medium along a main scanning direction, and a sub-scan that changes the relative positional relationship between the medium and the recording head along a sub-scanning direction that intersects with the main scanning direction, ejects the liquid from the recording head, and completes recording of a print image corresponding to an input image by performing the main scanning in multiple passes, an intermediate image forming step of forming an intermediate image on the medium based on the input image during a midway pass among the plurality of passes, the intermediate image including a mark portion that can be detected by a detection unit that detects the state of the liquid that has landed on the medium; a detecting step of detecting a state of the mark portion by the detecting unit; a remaining image forming step of forming a remaining image of the print image, excluding the intermediate image, on the medium in a pass subsequent to the intermediate pass; and performing processing based on the state of the mark portion detected by the detection portion.

Images