Printing apparatus, printing method, and printing program

Abstract

To provide a printing device that can execute printing having high color reproducibility using a plurality of heads.SOLUTION: A printing device comprises: a first head having a nozzle that discharges ink; a second head having a nozzle that discharges ink of the same color as the first head; a carriage that can support the first head and the second head and reciprocate; a memorizing device; and a control device, which has, as modes in which the first head and the second head perform printing in printing images, a first mode and a second mode for executing printing having higher color reproducibility in comparison with in the first mode. The control device executes printing by making the first head and the second head respectively discharge ink in printing in the first mode, and executes printing in a range narrower than a range in which printing is performed by one time reciprocation in the first mode, by making the first head and the second head respectively discharge ink by one time reciprocation, while sharing with each other at a predetermined sharing ratio, in printing in the second mode.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a printing apparatus, a printing method, and a printing program for printing an image such as an inkjet printer.

Background Art

[0002] In recent years, a technique of ejecting ink from a plurality of print heads to print on a printing object has been known (see, for example, Patent Document 1). In this technique, two print heads are provided on one carriage, and the two print heads are arranged so as to be shifted in a direction orthogonal to the scanning direction and partially overlap. With this technique, it is possible to move the carriage in the scanning direction and eject ink from the two print heads to perform high-speed printing on the printing object.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, since the color printed by the head of the printing apparatus does not necessarily become the color desired by the user, it may be adjusted by the user. In such a case, a method of performing color calibration by performing patch printing and color measurement is known.

[0005] On the other hand, in a printing apparatus provided with a plurality of heads as described above, a difference in color reproducibility occurs between the heads due to individual differences such as variations in manufacturing accuracy in each head. Examples of variations in manufacturing accuracy include manufacturing errors in the diameter of nozzles.

[0006] Therefore, patch printing is performed with a plurality of heads, the patch printing is colorimetrically measured, and adjustments for color reproduction are made with respect to the amount of ink ejected from the heads and the like. However, it is difficult to make the color reproduction performance the same among a plurality of print heads.

[0007] Accordingly, an object of the present invention is to provide a printing apparatus, a printing method, and a printing program capable of performing printing with high color reproducibility using a plurality of heads.

Means for Solving the Problems

[0008] A printing apparatus according to the present invention includes a first head having nozzles for ejecting ink, a second head having nozzles for ejecting ink of the same color as the first head, a carriage that supports the first head and the second head and is reciprocally movable, a storage device, and a control device. In printing an image, it has a first mode for printing with the first head and the second head, and a second mode for performing printing having higher color reproducibility than the first mode. In the printing in the first mode, the control device ejects the ink from each of the first head and the second head to perform printing. In the printing in the second mode, the first head and the second head share a predetermined ratio of responsibility, and the ink is ejected from each head in one reciprocating movement to perform printing in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode.

[0009] With this configuration, in the second mode for performing printing having higher color reproducibility than the first mode, the first head and the second head share a predetermined ratio of responsibility, and the ink is ejected from each head in one reciprocating movement to perform printing in a range (divided halftone printing) narrower than the range in which printing is completed in one reciprocating movement in the first mode. Therefore, it is possible to perform printing with high color reproducibility using the entire amount of ink ejected from the first head and the second head.

Effects of the Invention

[0010] According to the present invention, in a printing apparatus provided with a plurality of heads, it is possible to appropriately perform printing having high color reproducibility using the plurality of heads.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the printing apparatus 1 according to an embodiment of the present invention will be described. The printing apparatus 1 described below is merely one embodiment of the present invention. In the following embodiment, in printing in the first mode, printing is executed by discharging ink so that the responsible ratio in each of the first head 10 and the second head 20 is 100%, and in printing in the second mode, the responsible ratios of the first head 10 and the second head 20 are discharged from each head so that the total is 100% in total. Although an example of executing printing will be described, the responsible ratio is not limited to 100% as will be described later. Therefore, the present invention is not limited to the following embodiments, and addition, deletion, and modification are possible without departing from the spirit of the present invention.

[0013] FIG. 1 is a perspective view showing a printing apparatus 1 according to an embodiment. The concept of direction in this specification and the patent claim documents is, as shown in FIG. 1, the directions orthogonal to each other are the vertical direction, the horizontal direction, and the front-rear direction. Further, the horizontal direction is the main scanning direction Ds, and the front-rear direction is the sub-scanning direction (corresponding to the conveyance direction of the printing medium W) Df that is orthogonal to the main scanning direction Ds.

[0014] As shown in FIG. 1, the printing apparatus 1 of the present embodiment includes a housing 2, operation keys 4, a display unit 5, an ink tank 6, a tray 7, an upper cover 8, a carriage 3 that can reciprocate in the main scanning direction Ds, and a control device 50 (FIG. 2). The carriage 3 is provided with a first head 10 and a second head 20, which will be described later. The printing apparatus 1 has a first mode as a mode of printing with the first head 10 and the second head 20 in printing an image, and a second mode for executing printing having higher color reproducibility than this first mode.

[0015] The housing 2 is formed, for example, in a box shape. The housing 2 has an opening 2a for supplying the printing medium W in the front and a discharge port 2b for the printing medium W in the back. The printing medium W is fixed to the tray 7, and the tray 7 is conveyed in the sub-scanning direction Df intersecting the main scanning direction Ds which is the moving direction of the carriage 3 by a conveyance motor 32 (FIG. 2), which is a medium conveyance mechanism provided inside the housing 2. That is, the printing medium W is conveyed from the opening 2a to the discharge port 2b.

[0016] An operation key 4 is provided at a position in front of the right side of the housing 2. Also, a display unit 5 is provided at a position behind the operation key 4. The operation key 4 receives operation inputs from the user. The display unit 5 is constituted by, for example, a touch panel and displays predetermined information. A part of the display unit 5 also functions as an operation key at a predetermined timing. The control device 50 (FIG. 2) realizes a printing function based on external inputs such as inputs from the operation key 4 and controls the display on the display unit 5.

[0017] FIG. 2 is a block diagram showing the main configuration of the printing apparatus 1 shown in FIG. 1. As shown in FIG. 2, the printing apparatus 1 of the present embodiment includes a control device 50 corresponding to a computer having a CPU, a RAM 51, a ROM 52, and the like. Also, the printing apparatus 1 includes a storage device 40 for storing various information. The storage device 40 can use a flash memory, a hard disk drive, or the like. The storage device 40 can be included in the control device 50.

[0018] The RAM 51 temporarily stores a print job received from a computer 200 such as an external personal computer via the network interface 53. Also, the RAM 51 temporarily stores print data for each pass (the width printed by one head, including the width when printing using all the nozzles of one head and the width when printing using some of the nozzles). The ROM 52 stores a print program of the present embodiment and a control program for performing various data processes.

[0019] The printing apparatus 1 also includes a first head driver IC 15 that controls the first head 10 and a second head driver IC 25 that controls the second head 20. The printing apparatus 1 further includes a motor driver IC 31 that controls a carriage motor 30 for operating the carriage 3, and a motor driver IC 33 that controls a conveyance motor 32 which is a medium conveyance mechanism for the printing medium W. The conveyance motor 32 conveys a tray 7 on which the printing medium W is fixed in a conveyance direction (i.e., sub-scanning direction Df), which is a direction orthogonal to the direction in which the carriage 3 moves (i.e., main scanning direction Ds).

[0020] The control device 50 includes, as its functional components, an operation mode setting unit 50a, a responsibility ratio setting unit 50b, and a printing execution unit 50c. The operation mode setting unit 50a sets either a first mode or a second mode for executing printing with higher color reproducibility than the first mode when printing an image. The responsibility ratio setting unit 50b sets the responsibility ratio of the ink ejected by each of the first head 10 and the second head 20 with respect to the density of the dots constituting the image in the second mode. That is, the responsibility ratio setting unit 50b sets the responsibility ratio of the ink such that the respective responsibility ratios of the first head 10 and the second head 20 total 100% in the second mode. The responsibility ratios include, in addition to 50%:50%, 70%:30%, 60%:40%, etc. The printing execution unit 50c ejects ink so that the responsibility ratio is 100% in each of the first head 10 and the second head 20 and executes printing when set in the first mode. The printing execution unit 50c ejects ink from each head so that the responsibility ratios of the first head 10 and the second head 20 total 100% and executes printing when set in the second mode.

[0021] The information stored in the memory device 40 includes nozzle characteristic information indicating the ink ejection characteristics of a plurality of nozzles provided in the first head 10 and the second head 20. The nozzle characteristic information includes information indicating the variation in the diameters of the plurality of nozzles (hereinafter also referred to as "nozzle diameters") and information indicating the minimum droplet volume of the ink ejected from the plurality of nozzles. Further, the memory device 40 stores measurement values of the shape of the ink flow path in the first head 10 measured during the manufacture of the first head 10, measurement values of the shape of the ink flow path in the second head 20 measured during the manufacture of the second head 20, median values (design values) of the shape of the ink flow path in the first head 10, and median values (design values) of the shape of the ink flow path in the second head 20.

[0022] In addition, the memory device 40 stores priorities based on the arrangements of the first head 10 and the second head 20. The priorities will be described later.

[0023] By executing a predetermined printing program, the control device 50 controls the operation of the carriage motor 30 in the motor driver IC 31 and controls the operation of the conveyance motor 32 in the motor driver IC 33. Further, in parallel with this operation control, the control device 50 controls the operation of the first head 10 in the first head driver IC 15 and controls the operation of the second head 20 in the second head driver IC 25 based on raster data for ejecting ink droplets corresponding to the image formed on the printing medium W.

[0024] In this way, the motor driver IC 33 performs drive control of the conveyance motor 32 in response to an instruction from the control device 50, and the motor driver IC 31 performs drive control of the carriage motor 30 in response to an instruction from the control device 50. The first head driver IC 15 ejects ink from the first head 10 in response to an instruction from the control device 50. The second head driver IC 25 ejects ink from the second head 20 in response to an instruction from the control device 50. As a result, a predetermined amount of ink is ejected from the first head 10 and the second head 20.

[0025] That is, for the printing medium W, a conveyance process is executed to convey it from the upstream side to the downstream side in the conveyance direction by driving the conveyance motor 32. And for the carriage 3, a movement process is executed to move it in the main scanning direction Ds by driving the carriage motor 30. As a result, the carriage 3 is moved in the main scanning direction Ds, and ink ejection processes are performed from the first head 10 and the second head 20 provided on the carriage 3. These operations are linked to execute a printing process.

[0026] FIG. 3(a) is a plan view schematically showing the first head 10 and the second head 20 provided on the carriage 3 of the printing apparatus 1 shown in FIG. 1, and FIG. 3(b) is a plan view schematically showing the printing result by the first head 10 and the second head 20 in the second mode. As shown in FIG. 3(a), on the printing surface (lower surface) of the carriage 3, a first head 10 having nozzles for ejecting ink and a second head 20 having nozzles for ejecting ink of the same color as the first head 10 are supported. The first head 10 and the second head 20 are arranged shifted in the sub-scanning direction Df in a state where a part thereof overlaps.

[0027] The first head 10 and the second head 20 are each provided with a plurality of nozzle row groups corresponding to color inks. Each nozzle row group is arranged at regular intervals along the sub-scanning direction Df. The nozzle row groups of the first head 10 and the second head 20 are nozzle row groups 11, 21 for yellow (Y), nozzle row groups 12, 22 for magenta (M), nozzle row groups 13, 23 for cyan (C), and nozzle row groups 14, 24 for black (K), which are sometimes collectively referred to as color inks, for discharging inks of respective colors. Each nozzle row group includes a plurality of nozzles (black dots with "a" appended to the symbol of each nozzle row group). Only the nozzles at the ends are shown in this figure, but nozzles are provided over the entire surface of each nozzle row group. The number of nozzle row groups shown is an example. The nozzle row groups of the first head 10 and the second head 20 in this embodiment are arranged in the order of the nozzle row group 11, 21 for yellow (Y), the nozzle row group 12, 22 for magenta (M), the nozzle row group 13, 23 for cyan (C), and the nozzle row group 14, 24 for black (K) from the front (right direction) in the main scanning direction Ds in a state of being located at the standby position (the left end shown in FIG. 1).

[0028] Then, the control device 50 executes a duty ratio setting process in which the duty ratio setting unit 50b sets the duty ratio of the inks discharged by the first head 10 and the second head 20 with respect to the density of the dots constituting the image printed in the second mode. The duty ratios of the first head 10 and the second head 20 can be determined based on the conditions in the selection of the head with a higher duty ratio described later.

[0029] As the process of setting the responsibility ratio borne by the first head 10 and the second head 20 in the second mode, it can be made different between the first head 10 and the second head 20 by the control device 50. For example, as shown in Fig. 3(b), printing can be executed such that the first head 10 is responsible for 50% and the second head 20 is responsible for 50%, resulting in 100% in total, or printing can be executed with other responsibility ratios. That is, in the second mode, printing is performed by the first head 10 and the second head 20 cooperating to reproduce one color. Out of the total ink ejection amount of 100%, the ink corresponding to the responsibility ratio of the first head is ejected from the first head 10, and the ink corresponding to the responsibility ratio of the second head is ejected from the second head 20, and then printing is executed. The responsibility ratios of the first head 10 and the second head 20 are set at ratios greater than 0% for both the first head 10 and the second head 20 and totaling 100%. For example, when the responsibility ratio of the first head 10 is 30% and the responsibility ratio of the second head 20 is 70%, the control device 50 divides the rasterized raster data into raster data for the first head 10 and raster data for the second head 20. The control device 50 performs a masking process of applying a mask to the raster data for the first head 10 and the raster data for the second head 20. Since the responsibility ratio of the first head 10 is 30%, the raster data for the first head 10 is generated to be raster data for ejecting ink for 30% of the original raster data using mask data that masks 70% of the original raster data. Also, since the responsibility ratio of the second head 20 is 70%, the raster data for the second head 20 is generated to be raster data for ejecting ink for 70% of the original raster data using mask data that masks 30% of the original raster data. Then, in the printing process, the first head 10 ejects ink based on the raster data for the first head 10 to perform printing corresponding to the responsibility ratio. Also, in the printing process, the second head 20 ejects ink based on the raster data for the second head 20 to perform printing corresponding to the responsibility ratio.

[0030] FIG. 4 is a schematic view showing the arrangement of the ink tank 6, the first head 10, and the second head 20 in the printing apparatus 1 shown in FIG. 1, and the conveyance direction of the printing medium W. In FIG. 4, the nozzle row group shown in FIG. 3(a) is shown only in shades. Note that the ink tank 6 includes four colors as described above, but is shown as one in FIG. 4. The ink tank 6 provided in the printing apparatus 1 and the first head 10 are connected by a first ink tube 16 which is an ink flow path, and the ink tank 6 and the second head 20 are connected by a second ink tube 26 which is an ink flow path. Since the first head 10 and the second head 20 are arranged shifted in the sub-scanning direction Df in a state where a part thereof overlaps, the second ink tube 26 is longer than the first ink tube 16 in this example.

[0031] Further, the printing medium W is conveyed in the sub-scanning direction Df by a medium conveyance mechanism and discharged from the discharge port 2b (FIG. 1). In this example, the second head 20 is located upstream of the conveyance direction of the printing medium W (sub-scanning direction Df indicated by an arrow). Also, in this example, the second head 20 is located upstream of the main scanning direction Ds of the carriage 3. Based on these conditions, priorities based on the arrangements of the first head 10 and the second head 20 are set and stored in the storage device 40.

[0032] As the priority, among the first head 10 and the second head 20, the head corresponding to the shorter ink tube among the first ink tube 16 and the second ink tube 26 can be stored as the head with a higher priority. Also, as another priority, among the first head 10 and the second head 20, the head located downstream in the conveyance direction of the printing medium W can be stored as the head with a higher priority. Also, as another priority, among the first head 10 and the second head 20, the head closer to the discharge port 2b can be stored as the head with a higher priority. Details of the priority will be described later.

[0033] According to the printing apparatus 1 configured as described above, in printing in the first mode, the control apparatus 50 discharges ink so that the responsibility ratio in each of the first head 10 and the second head 20 is 100%, and executes printing. Then, in printing in the second mode, the control apparatus 50 discharges ink from each head so that the total responsibility ratio of the first head 10 and the second head 20 is 100%, and executes printing.

[0034] FIG. 5 is a flowchart showing an example of operation mode setting by the control apparatus 50 of the printing apparatus 1 shown in FIG. 1. The operation mode setting unit 50a of the control apparatus 50 sets either the first mode or the second mode as follows.

[0035] After the start, image data for one pass is input to the control apparatus 50 (S10), the image data is referred to, and a lookup table (hereinafter referred to as "LUT") is read (S11). The LUT includes, for example, a case where, in addition to an RGB table without color correction, there is a conversion table of RGB with color correction. The LUT with color correction includes a LUT having data of "RGB" with color correction from the original "RGB" and the like.

[0036] Then, the control device 50 determines whether there is a reference destination (conversion table after color correction) in the LUT (S12). If there is a reference destination in the LUT, the color-corrected "RGB" data is referenced (S13). If there is no reference destination in the LUT, the original "RGB" normal data is referenced (S14). Thereafter, color conversion is performed based on the LUT (S15). Then, it is determined whether all of one pass has been converted (S16). If not all of one pass has been converted, the process returns to the LUT reading (S11) and the above determination is repeated. If all of one pass has been converted, it is determined whether the calibration LUT was referenced during color conversion (S17). If the calibration LUT was referenced during color conversion, it is determined that printing is in the second mode (S18), and the process ends. If the calibration LUT was not referenced during color conversion, it is determined that printing is in the first mode (S19), and the process ends. Note that since differences in color development and the like can occur when the media of the printing target are different, a LUT corresponding to the media may be selected in advance.

[0037] When the printing that causes the carriage 3 equipped with the first head 10 and the second head 20 to scan in the main scanning direction Ds is determined by the control device 50 to be printing in the first mode (S19), ink is ejected from each of the first head 10 and the second head 20 to execute printing. On the other hand, when the control device 50 determines that it is printing in the second mode (S18), the first head 10 and the second head 20 share the work in a predetermined ratio, and ink is ejected from each head during one reciprocating movement of the carriage 3 scanning in the main scanning direction Ds, and printing is executed in a range narrower than the range where printing is completed in one reciprocating movement in the first mode. As a specific example when it is determined that it is printing in this second mode (S18), the first head 10 and the second head 20 each share the work in a predetermined ratio so that the total is 100%, and ink is ejected to execute printing for a total of one pass (divided halftone printing). In this case, the feed amount of the printing medium W is the feed amount for one head. On the other hand, as a specific example when the control device 50 determines that it is printing in the first mode (S19), ink for one pass is ejected so that the share ratio of each of the first head 10 and the second head 20 is 100%, and printing for a total of two passes is executed. In this case, the feed amount of the printing medium W is the feed amount for two heads, namely the first head 10 and the second head 20. Note that these one pass includes the width when printing using all the nozzles of one head as described above, and the width when printing using some of the nozzles. Also, the printing for two passes in the first mode does not include printing (singling printing) that prevents a non-printed portion from remaining at the boundary portion by partially overlapping with the adjacent pass at both sides (boundary portions with adjacent passes) of one pass. That is, the printing for two passes is the width printed by the first head 10 and the second head 20 supported by the carriage 3, and includes cases where it is less than twice the printing width of one pass assuming printing for one pass using all nozzles.

[0038] Next, in the second mode, which head of the first head 10 and the second head 20 is selected as the head with a higher ink discharge ratio will be described. For example, as an example of sharing at a predetermined ratio between the first head 10 and the second head 20, there are a ratio of 70%:30%, 60%:40%, etc. In the following description, the selection of the head with a higher ratio will be mainly described. The control device 50 executes a ratio setting process for setting the ink discharge ratio of each of the first head 10 and the second head 20 with respect to the density of dots constituting the image in the second mode. The ratio setting process is performed by the ratio setting unit 50b of the control device 50. As the head with a higher ink discharge ratio in the second mode, a head with good conditions, a head with easy ink volume adjustment, etc. are selected.

[0039] FIG. 6 is a flowchart showing a first example of the selection process by the control device 50 shown in FIG. 2. FIG. 6 is an example of a first selection process for selecting either the first head 10 or the second head 20 as the head with a higher ink discharge ratio during printing in the second mode by the first head 10 and the second head 20.

[0040] The storage device 40 stores nozzle characteristic information indicating the ink discharge characteristics of the nozzles. The nozzle characteristic information can include the variation in the diameter of the nozzles, the minimum droplet volume of the ink discharged from the nozzles, etc., including the quality of the nozzle state.

[0041] Then, as shown in FIG. 6, as the first selection process, the control device 50 acquires nozzle characteristic information (S20). The nozzle characteristic information can be information regarding the state of the nozzles. The information regarding the state of the nozzles includes, for example, results of printing measurement tests during manufacturing, such as that the variation in nozzle diameters is small and that nozzles with a low minimum droplet volume are not included. Then, based on the nozzle characteristic information, the control device 50 determines whether the first head 10 is in a better state than the second head 20 (S21). For example, if the first head 10 has a smaller variation in nozzle diameters and does not include nozzles with a low minimum droplet volume, it is determined that the first head 10 is in a better state. If the first head 10 is in a better state, the first head 10 is selected as the head with a higher responsibility ratio (S22), and the first selection process ends. If it is determined (in S1) that the second head 20 is in a better state, the second head 20 is selected as the head with a higher responsibility ratio (S23), and the first selection process ends. Thus, in the first example, based on the fact that ink ejection is more stable for the head in a better state, the head with a higher responsibility ratio is selected.

[0042] In the above first selection process, the determination (S21) as to whether the first head 10 is in a better state than the second head 20 can be implemented in the following embodiments.

[0043] As one embodiment, the nozzle characteristic information can be information indicating the variation in diameters of a plurality of nozzles in the first head 10 and the second head 20. Then, in the first selection process in the printing in the second mode, the control device 50 can select, as the head with a higher ink responsibility ratio, the head with less variation in nozzle diameters among the first head 10 and the second head 20. This selection is based on the fact that the less the variation in nozzle diameters, the more stable the ink ejection.

[0044] Also, as one embodiment, the nozzle characteristic information can be information indicating the minimum droplet volume of ink ejected from a plurality of nozzles in the first head 10 and the second head 20. Then, in the first selection process, the control device 50 can select, as the head with a higher ink responsibility ratio, the head with a larger minimum droplet volume ejected from the nozzles among the first head 10 and the second head 20. This selection is based on the fact that it is easier to correct the ink amount for the head with a larger minimum droplet volume.

[0045] FIG. 7 is a flowchart showing a second example of the selection process by the control device 50 shown in FIG. 2. As described above, the first head 10 and the second head 20 supported by the carriage 3 are arranged with a partial overlap and shifted in the sub-scanning direction Df as shown in FIG. 3(a) above. For this reason, in printing in the second mode, the control device 50 can perform printing by normally distributing ink so that there is no printing disturbance in the printing area where the first head 10 and the second head 20 overlap in the sub-scanning direction Df. For the printing area where the first head 10 and the second head 20 do not overlap in the sub-scanning direction Df, ink is ejected from each head in accordance with the responsibility ratio for printing. The control device 50 can thus prevent a decrease in color reproducibility in the overlapping portion between the first head 10 and the second head 20. For the nozzles corresponding to the printing area where the first head 10 and the second head 20 do not overlap, the control device 50 ejects ink from the first head 10 and the second head 20 so as to achieve their respective responsibility ratios for printing. Note that normal distribution means that for the printing area where the first head 10 and the second head 20 overlap in the sub-scanning direction Df, the use ratio of the first head 10 and the second head 20 is predetermined so that the use ratio is 100% in total, and the density difference is small enough that the user hardly recognizes the density difference, which is different from the printing area where the first head 10 and the second head 20 do not overlap in the sub-scanning direction Df. The use ratio is stored in the storage device 40 in advance and may be different from the responsibility ratio.

[0046] As shown in the figure, when the selection process is started, the control device 50 acquires nozzle characteristic information (S30). After that, the control device 50 first determines whether or not there is wobbling in the first head 10 (S31). "Wobbling" includes, for example, "a state in which ink droplets land deviating from a predetermined position on the recording paper". "Wobbling" can be confirmed in advance, for example, by a pinch check pattern or a nozzle unevenness pattern in the process. The determination of whether or not "wobbling" has occurred can be made based on whether or not the number of times "wobbling" has occurred exceeds a predetermined threshold. When wobbling occurs in the first head 10, it is determined whether or not the ink ejection portion is a portion where the first head 10 and the second head 20 overlap (S32). When the ink ejection portion is a portion where the first head 10 and the second head 20 overlap, the control device 50 determines it as normal distribution (S33), and the selection process ends. When the ink ejection portion is not a portion where the first head 10 and the second head 20 overlap, the control device 50 selects the second head 20 as the head with a high ink share ratio (S34), and the selection process ends.

[0047] In the determination (S31) of whether or not there is wobbling in the first head 10, when there is no wobbling in the first head 10, the control device 50 determines whether or not there is wobbling in the second head 20 (S35). When wobbling occurs in the second head 20, the control device 50 determines whether or not the ink ejection portion is a portion where the first head 10 and the second head 20 overlap (S36). When the ink ejection portion is a portion where the first head 10 and the second head 20 overlap, the control device 50 determines it as normal distribution (S37), and ends the selection process. When the ink ejection portion is not a portion where the first head 10 and the second head 20 overlap, the control device 50 selects the first head 10 as the head with a high ink share ratio (S38), and ends the selection process.

[0048] When the control device 50 determines whether or not there is wobbling in the second head 20 in the determination (S35), if there is no wobbling in the second head 20, the control device 50 determines whether the nozzle diameter of the second head 20 is smaller than that of the first head 10 (S39). When the nozzle diameter of the second head 20 is small, the control device 50 selects the first head 10 as the head with a high ink share ratio (S40) and ends the selection process. When the nozzle diameter of the second head 20 is large, the control device 50 selects the second head 20 as the head with a high ink share ratio (S41) and ends the selection process. Thus, in the second example, based on the fact that the number of occurrences of wobbling is small and it is easier to correct nozzle unevenness when the nozzle diameter is large, the head with a high share ratio is selected. Also, whether the printing area is a portion where the first head 10 and the second head 20 overlap is also used as a determination condition.

[0049] FIG. 8 is a schematic diagram of image processing in which the color gamut changes when the first head 10 and the second head 20 shown in FIG. 1 are moved and printed in the right direction (forward direction) of the main scanning direction Ds and when they are moved and printed in the left direction (return direction) of the main scanning direction Ds. FIG. 9 is a flowchart showing a third example of the selection process by the control device 50 shown in FIG. 2. FIG. 8 is a simplified diagram for explaining the image processing.

[0050] Incidentally, as shown in FIG. 3(a), each of the first head 10 and the second head 20 has a plurality of nozzles in which each nozzle row group is arranged at regular intervals along the sub-scanning direction Df. And the nozzle row groups of the first head 10 and the second head 20 in this embodiment are arranged in the order of the yellow (Y) nozzle row groups 11, 21, the magenta (M) nozzle row groups 12, 22, the cyan (C) nozzle row groups 13, 23, and the black (K) nozzle row groups 14, 24 from the front in the main scanning direction Ds in a state where they are located at the standby position (the left end shown in FIG. 1).

[0051] In the case of such an arrangement of nozzle arrays, when the carriage 3 is reciprocated in the main scanning direction Ds for printing by bidirectional scanning, when scanning from left to right, ink is ejected in order from yellow (Y), but when scanning from right to left, ink is ejected in order from black (K). As a result, the color gamut in the forward direction when printing the carriage 3 by one-way scanning is different from the color gamut in the return direction when printing by bidirectional scanning.

[0052] On the other hand, as shown in FIG. 8, the image to be printed divides one pass into a plurality of blocks before printing, and derives RGB values for each block unit. Then, a weight indicating whether color reproducibility can be maintained from the RGB values is calculated for each block unit. If there is a block in which the weight per unit area exceeds a threshold value, control is performed to print that pass by one-way scanning (in this embodiment, forward direction scanning). This weight threshold is determined by whether the color gamut changes. When the color gamut changes in the ink ejection order during printing, the control device 50 controls to print by one-way scanning in the main scanning direction Ds (in this embodiment, the forward direction) in which the color gamut becomes wider.

[0053] Note that the weights exemplified for each block unit in FIG. 8 are merely examples. In this example, it is assumed that "1.0" exceeds the threshold value. When printing a pass including a block with a weight of "1.0", printing is performed by one-way scanning.

[0054] As shown in FIG. 9, in the selection process for the change in the color gamut by the control device 50, the acquisition of head characteristic information is performed (S50). After that, it is determined whether the color gamut changes by a predetermined amount or more between rightward printing (forward printing) and leftward printing (return printing) for the image to be printed (S51). Specifically, when there is even one block in one pass whose weight exceeds the threshold value, the control device 50 determines that the color gamut changes by a predetermined amount or more between rightward printing (forward printing) and leftward printing (return printing). When the color gamut changes by a predetermined amount or more, the control device 50 performs printing only in the direction in which the color gamut becomes wider, and the second mode is selected (S52). In this case, the responsibility ratio between the first head 10 and the second head 20 can be, for example, 100:0. In this case, since it is one-way printing, the printing speed decreases. When the color gamut does not change by a predetermined amount or more, the control device 50 performs normal distribution printing, and the second mode is selected (S53). In this case, the responsibility ratio between the first head 10 and the second head 20 can be, for example, 50:50. In this case, since it is two-way printing, the printing speed increases. Then, the control device 50 determines whether the selection process has been completed for all the blocks in one pass (S54). If not, the above determination (S51) is repeated. If the selection process has been completed for all the blocks in one pass, the selection process ends.

[0055] After that, the control device 50 discharges ink from the first head 10 and the second head 20 so as to have a predetermined responsibility ratio in the second mode and executes printing. Thereby, it is possible to prevent a decrease in color reproducibility due to a change in the color gamut.

[0056] FIG. 10 is a flowchart showing a fourth example of the selection process by the control device 50 shown in FIG. 2. FIG. 10 is an example of selecting the head with a higher ink discharge amount responsibility ratio when printing in the second mode based on the manufacturing errors of the first head 10 and the second head 20.

[0057] The memory device 40 can store, as head characteristic information, the measured values and median values (design values and representative values) of the ink flow paths in the first head 10 measured during the manufacture of the first head 10, and the measured values and median values (design values and representative values) of the ink flow paths in the second head 20 measured during the manufacture of the second head 20.

[0058] Then, in the second selection process in the printing in the second mode, the control device 50 acquires the head characteristic information (S60), and determines whether the measured value of the flow path of the first head 10 is closer to the median value than the measured value of the flow path of the second head 20 (S61). Then, when the first head 10 is closer to the median value than the second head 20, the control device 50 selects the first head 10 as the head with a higher responsibility ratio (S62) and ends the second selection process. On the other hand, when the measured value of the flow path of the second head 20 is closer to the median value than the measured value of the flow path of the first head 10, the control device 50 selects the second head 20 as the head with a higher responsibility ratio (S63) and ends the second selection process. Thus, in the fourth example, the control device 50 selects the head with a higher responsibility ratio based on the fact that the ink ejection is more stable when the measured value of the ink flow path in the head is closer to the median value of the flow path.

[0059] Incidentally, as shown in FIG. 4, the ink tank 6 provided in the printing apparatus 1 is connected to the first head 10 by a first ink tube 16, and the ink tank 6 is connected to the second head 20 by a second ink tube 26. Also, based on the arrangement of the first head 10 and the second head 20 with respect to the conveyance direction (sub-scanning direction Df) of the printing medium W, the arrangement of the printing medium W with respect to the main scanning direction Ds in which the first head 10 and the second head 20 move, etc., it is possible to set the priority of which of the first head 10 and the second head 20 is more advantageous to select as the head with a higher ink responsibility ratio. The priority can be set based on factors such as advantageous ink supply and low possibility of damage. The memory device 40 stores the priority based on the arrangement of the first head 10 and the second head 20.

[0060] Then, the control device 50 executes a responsibility ratio setting process for setting the responsibility ratio of the ink discharged by each of the first head 10 and the second head 20 with respect to the density of the dots constituting the image in the second mode. The control device 50 executes a third selection process of selecting one of the first head 10 and the second head 20 as the head with a higher responsibility ratio of the ink based on the above-mentioned high priority. By this third selection process, the head with a higher responsibility ratio of the ink discharge amount is selected based on the arrangement of the first head 10 and the second head 20. The priority is set higher in a more advantageous manner based on, for example, the lengths of the ink flow paths of the first head 10 and the second head 20, the arrangement of the first head 10 and the second head 20, and the like. Specifically, the third selection process can be performed as follows.

[0061] In the third selection process, the control device 50 can determine the head corresponding to the shorter ink tube among the first ink tube 16 (FIG. 4) and the second ink tube 26 (FIG. 4) among the first head 10 and the second head 20 as the head with a higher priority, and select it as the head with a higher responsibility ratio of the ink. This selection is based on the fact that the head with a shorter ink tube is easier to supply ink. Specifically, in FIG. 4, the first ink tube 16 is shorter than the second ink tube 26. The shorter the ink tube, the easier it is to supply ink. It can be said that the state of the first head 10 is good because the first ink tube 16 is shorter than the second ink tube 26 of the second head 20.

[0062] Also, in the third selection process, the control device 50 can determine, among the first head 10 and the second head 20, the head located on the downstream side when the carriage 3 moves in the main scanning direction Ds from the standby position as the head with a higher priority, and select it as the head with a higher ink responsibility ratio. This selection is based on the fact that the head located on the downstream side in the main scanning direction Ds when the carriage 3 moves in the main scanning direction Ds from the standby position (the position in FIG. 1) has a better state because it has fewer printing opportunities. Specifically, in FIG. 1, when the carriage 3 starts to move in the main scanning direction Ds from the standby position, the second head 20 starts printing first. Since the carriage 3 usually starts moving from the standby position, the first head 10 has fewer printing opportunities compared to the second head 20. It can be said that the state of the first head 10 is good because it has fewer printing opportunities compared to the second head 20.

[0063] Also, in the third selection process, the control device 50 can determine, among the first head 10 and the second head 20, the head closer to the discharge port 2b as the head with a higher priority, and select it as the head with a higher ink responsibility ratio. This selection is based on the fact that the head closer to the discharge port 2b has a better state because it has fewer opportunities to contact the printed medium W compared to the upstream side in the conveyance direction of the printed medium W. Specifically, in FIG. 1, the first head 10 is the head closer to the discharge port 2b. The tray 7 moves from front to back in FIG. 1 by the driving force of the conveyance motor 32. Since the second head 20 is in front of the first head 10, when the printed medium W fixed to the tray 7 moves backward together with the tray 7, there is a possibility that the second head 20 contacts the printed medium W before the first head 10. When the second head 20 contacts the printed medium W, the user or the printing apparatus 1 stops the movement of the tray 7 at the moment when the printed medium W contacts the second head 20 in order to prevent damage to the second head 20. Therefore, the possibility that the printed medium W contacts the first head 10 is lower than the possibility that the printed medium W contacts the second head 20. It can be said that the state of the first head 10 is good because it has fewer opportunities to contact the printed medium W compared to the upstream side in the conveyance direction of the printed medium W.

[0064] FIG. 11 is a flowchart showing a fifth example of the selection process by the control device 50 of the printing apparatus 1 shown in FIG. 1. FIG. 11 is an example of selecting a head with a high ink discharge ratio when printing in the second mode based on the usage history of the first head 10 and the second head 20.

[0065] The storage device 40 can store, as usage history, information on the usage time since the replacement of the first head 10 and information on the usage time since the replacement of the second head 20. Also, the storage device 40 can store, as usage history, information on the total ink discharge amount in the first head 10 and information on the total ink discharge amount in the second head 20. Further, the storage device 40 can store, as usage history, information on the pinhole occurrence opportunities in the first head 10 and the second head 20. Also, the storage device 40 can store, as usage history, the number of purges (including both suction purges and pressure purges) in the first head 10 and the second head 20. The pinhole occurrence opportunities can store the number of times when ink cannot be discharged from the nozzles. The number of purges stores the number of times ink has been discharged from the head.

[0066] Then, in the printing in the second mode, the control device 50 acquires the head usage history information (S70), and determines whether the second head 20 has been used more than the first head 10 (S71). This determination is made based on the above usage time information, total ink discharge amount information, and information such as fewer pinhole occurrence opportunities. If, in this determination, the second head 20 has been used more than the first head 10, the control device 50 selects the first head 10 as the head with a high ink discharge ratio (S72), and ends the second selection process. On the other hand, if the second head 20 has not been used more than the first head 10, the control device 50 selects the second head 20 as the head with a high ink discharge ratio (S73), and ends the selection process. In such a fifth example, a head in good condition is determined based on information such as the head usage time information, total ink discharge amount information, and pinhole information, and is selected as the head with a high ink discharge ratio.

[0067] Figure 12 is a flowchart showing a sixth example of the selection process by the control device 50 of the printing device 1 shown in Figure 1. Figure 12 is an example of a fourth selection process for selecting either the first head 10 or the second head 20 as the head with a higher responsibility ratio for ink discharge amount during printing in the second mode.

[0068] The storage device 40 can store, as usage history, the history of the number of executions of the cleaning process for the first head 10 and the history of the number of executions of the cleaning process for the second head 20. Also, the storage device 40 can store, as usage history, the information on the elapsed time after replacement of the first head 10 and the information on the elapsed time after replacement of the second head 20. Further, the storage device 40 can store, as usage history, the information on the total ink discharge amount in the first head 10 and the information on the total ink discharge amount in the second head 20.

[0069] Then, in the fourth selection process in the printing in the second mode, the control device 50 determines, for the first head 10 and the second head 20, which head has a smaller number of executions of the cleaning process, which head has a shorter elapsed time, and which head has a smaller total discharge amount. The control device 50 can select one of the heads as the head with a higher responsibility ratio for ink from the result. In this way, the control device 50 can appropriately determine which state of the first head 10 and the second head 20 is better and select the head with a better state as the head with a higher responsibility ratio for ink. Specifically, the fourth selection process can be performed as follows.

[0070] In the fourth selection process, the control device 50 acquires the head usage history (S80). Then, the control device 50 determines whether the difference in the number of cleaning times between the second head 20 and the first head 10 is equal to or greater than a predetermined threshold (S81). If, in this determination, the difference in the number of cleaning times does not exceed the predetermined threshold, the control device 50 selects the second head 20 as the head with a higher ink responsibility ratio (S82) and ends the fourth selection process. This selection is based on the fact that a head with a smaller number of cleaning times is in a better state.

[0071] Further, in the determination (S81), the control device 50 can select, as the head with a higher ink responsibility ratio, the head among the first head 10 and the second head 20 whose cleaning times do not exceed the threshold. This selection is based on the fact that a head whose cleaning times do not exceed the threshold is in a better state. In this embodiment, when the number of cleaning times of the second head 20 is large and is equal to or greater than a predetermined threshold compared to the difference in the number of cleaning times with the first head 10, the control device 50 determines whether the usage time of the second head 20 is longer than the first head 10 by a predetermined time or more (S83). If, in this determination, the usage time of the second head 20 is not longer than the predetermined time or more, the control device 50 selects the second head 20 as the head with a higher ink responsibility ratio (S82) and ends the fourth selection process. This selection is based on the fact that a head with a smaller number of usage times is in a better state.

[0072] Also, in the fourth selection process, the control device 50 can select, as the head with a higher ink responsibility ratio, the head with less elapsed time from the usage history among the first head 10 and the second head 20. This selection is based on the fact that a head with less elapsed time since the start of use is in a better state.

[0073] Also, in this embodiment, when the usage time of the second head 20 is longer than the usage time of the first head 10 by a predetermined time or more, the control device 50 determines whether the total ink discharge amount of the second head 20 is larger than that of the first head 10 (S84). In this determination, if the total ink discharge amount of the second head 20 is not large, the second head 20 is selected as the head with a high ink share ratio (S82), and the fourth selection process is terminated. In this determination, if the total ink discharge amount of the second head 20 is large, the first head 10 is selected as the head with a high ink share ratio (S85), and the fourth selection process is terminated. This selection is based on the fact that a head with a small total ink discharge amount is in a good state.

[0074] Further, in the fourth selection process, the control device 50 can select, as the head with a high ink share ratio, the head with a small total ink discharge amount from among the first head 10 and the second head 20 based on the usage history. This selection is based on the fact that a head with a small total ink discharge amount is in a good state.

[0075] In this way, in the second mode, the control device 50 selects either the first head 10 or the second head 20 as the head with a high share ratio and executes printing by discharging ink so that the total is 100%. As a result, it is possible to appropriately execute printing with high color reproducibility by increasing the share ratio of the more stable head.

[0076] The selection process by the control device 50 can be implemented as follows. The following embodiment is an example of setting the ink share ratios of the first head 10 and the second head 20 according to the states of the nozzles in each nozzle row group of the first head 10 and the second head 20.

[0077] In one embodiment, when the control device 50 executes the duty ratio setting process of setting the duty ratio of the ink discharged by each of the first head 10 and the second head 20 with respect to the density of the dots constituting the image printed in the second mode in the duty ratio setting unit 50b, a predetermined mask is used, but it is not limited thereto. The control device 50 may generate a new mask in the duty ratio setting unit 50b.

[0078] (1) The new mask determines whether or not misregistration has occurred for all the nozzles assigned the same number in each nozzle row group of the first head 10 and the second head 20. Then, the nozzles with misregistration are masked, and ink is discharged using the nozzles without misregistration to execute printing. In this case, the ink corresponding to the duty ratio of the masked nozzles in the head having the masked nozzles is configured to be discharged from the nozzles of the other head.

[0079] Also, (2) when misregistration has not occurred in both of the nozzles assigned the same number in each nozzle row group of the first head 10 and the second head 20, and when the ink discharge portions of both of the nozzles assigned the same number of the first head 10 and the second head 20 are located in the overlapping portion of the first head 10 and the second head 20, similar to the mask set so that a density difference occurs between the printing area of the overlapping portion of the first head 10 and the second head 20 and the printing area of the portion where the first head 10 and the second head 20 do not overlap in the sub-scanning direction Df and it is difficult for the user to recognize the density difference, the nozzles to be used are not masked, and the nozzles not to be used are configured to be masked.

[0080] Also, (3) when, in the nozzle row groups of each of the first head 10 and the second head 20, both nozzles assigned the same number do not have their ink ejection parts located in the overlapping part between the first head 10 and the second head 20, the new mask is configured to mask the nozzles not to be used without masking the nozzles to be used, based on the nozzle diameter of the corresponding nozzle of the first head 10 and the nozzle diameter of the corresponding nozzle of the second head 20. Specifically, when the nozzle diameter of the corresponding nozzle of the first head 10 is larger than the nozzle diameter of the corresponding nozzle of the second head 20, the new mask does not mask the corresponding nozzle of the first head 10 and masks the corresponding nozzle of the second head 20. On the other hand, when the nozzle diameter of the corresponding nozzle of the second head 20 is larger than the nozzle diameter of the corresponding nozzle of the first head 10, the new mask does not mask the corresponding nozzle of the second head 20 and masks the corresponding nozzle of the first head 10.

[0081] Note that these new masks may be generated by a human. In FIG. 5 described above, when all of one pass has been converted, the control device 50 determines whether or not a calibration LUT was referred to during color conversion (S17). If a calibration LUT was referred to during color conversion, printing is performed in the second mode (S18), and the new mask is used for printing in the second mode. On the other hand, when the control device 50 does not refer to the calibration LUT during color conversion and printing is performed in the first mode (S19), the new mask is not used.

[0082] As described above, the printing apparatus 1 includes a first mode and a second mode for performing printing having higher color reproducibility than the first mode when printing an image. In the first mode, printing is executed by ejecting ink so that the responsible ratio is 100% in each of the first head 10 and the second head 20. Then, in the second mode, printing is executed by ejecting ink from each head so that the total responsible ratio of the first head 10 and the second head 20 is 100%. Therefore, in printing that requires high color reproducibility, it is possible to execute printing having high color reproducibility by ejecting ink with a responsible ratio of 100% in total from each of the first head 10 and the second head 20 in the second mode.

[0083] In one embodiment, the printing execution unit 50c executes printing by ejecting ink so that the responsible ratio is 100% in each of the first head 10 and the second head 20 in the state set to the first mode, but it is not limited thereto. In the state set to the first mode, the printing execution unit 50c may eject ink so that the responsible ratio is approximately 100% in each of the first head 10 and the second head 20. Approximately 100% includes a range of about 95% to 105%.

[0084] Also, in one embodiment, the printing execution unit 50c executes printing by ejecting ink from each head so that the total responsible ratio of the first head 10 and the second head 20 totals 100% in the state set to the second mode, but it is not limited thereto. In the state set to the second mode, the printing execution unit 50c may execute printing by ejecting ink from each head so that the total responsible ratio of the first head 10 and the second head 20 totals approximately 100%. Approximately 100% includes a range of about 95% to 105%.

Explanation of Reference Numerals

[0085] 1 Printing apparatus 2 Housing 2a Opening 2b Discharge port 3 Carriage 6 Ink tank 10 First head 16 First ink tube 20 Second head 26 Second ink tube 30 Carriage motor 32 Conveying motor (medium conveying device) 40 Storage device 50 Control device 50a Operation mode setting unit 50b Responsible ratio setting unit 50c Printing execution unit 51 RAM 52 ROM Ds Main scanning direction Df Sub-scanning direction W Printed medium

Claims

1. A first head having nozzles for ejecting ink, A second head having nozzles for ejecting ink of the same color as the first head, A carriage that supports the first head and the second head and is capable of reciprocating movement, A storage device, A control device, and includes, In the printing of an image, there are a first mode in which printing is performed by the first head and the second head, and a second mode for performing printing having higher color reproducibility than the first mode. The control device, In the printing in the first mode, the ink is ejected from each of the first head and the second head to perform printing. In the printing in the second mode, the first head and the second head share a predetermined responsibility ratio, and the ink is ejected from each head during one reciprocating movement, and printing is performed in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode. The storage device stores nozzle characteristic information indicating the ink ejection characteristics of the nozzles. The control device executes a responsibility ratio setting process for setting the responsibility ratio of the ink ejected by each of the first head and the second head with respect to the density of dots constituting an image in the second mode, and based on the nozzle characteristic information, executes a first selection process for selecting, from the first head and the second head, the head having a high responsibility ratio as the responsibility ratio of the ink in the responsibility ratio setting process. A printing apparatus.

2. The first head and the second head each have a plurality of the nozzles. The nozzle characteristic information is information indicating variations in the diameters of the nozzles. The control device selects, in the first selection process, the head having less variation in the diameters of the nozzles among the first head and the second head as the head having a high responsibility ratio of the ink. The printing apparatus according to claim 1.

3. The first head and the second head each have a plurality of the nozzles. The nozzle characteristic information is information indicating the minimum droplet amount of the ink ejected from the nozzles. The control device selects, in the first selection process, the head having a large minimum droplet amount ejected from the nozzles among the first head and the second head as the head having a high responsibility ratio of the ink. The printing apparatus according to claim 1.

4. A first head having nozzles for ejecting ink, A second head having nozzles that eject ink of the same color as the first head; A carriage that supports the first head and the second head and is capable of reciprocating movement; A storage device; A control device, and includes: In the printing of an image, there are a first mode in which printing is performed by the first head and the second head, and a second mode for performing printing having higher color reproducibility than the first mode. The control device: In the printing in the first mode, the ink is ejected from each of the first head and the second head to perform printing. In the printing in the second mode, printing is performed in a range where the range for completing printing in one reciprocating movement is narrower than the range for completing printing in one reciprocating movement in the first mode. When the first head and the second head have a nozzle arrangement in which a color gamut changes between forward direction printing when printing in a one-way scan in the main scanning direction, which is the moving direction of the carriage, and return direction printing when printing in a bidirectional scan. When the color gamut changes by a predetermined amount or more between the forward direction printing and the return direction printing for an image to be printed for one pass, the control device sets to the second mode and ejects the ink only from the first head to perform printing in the one-way scan. When the color gamut does not change by a predetermined amount or more between the forward direction printing and the return direction printing, the control device sets to the second mode and the first head and the second head share at a predetermined ratio, and ejects the ink from each of the first head and the second head to perform printing in the bidirectional scan. A printing apparatus.

5. A first head having nozzles that eject ink; A second head having nozzles that eject ink of the same color as the first head; A carriage that supports the first head and the second head and is capable of reciprocating movement; A storage device; A control device, and includes: In the printing of an image, there are a first mode in which printing is performed by the first head and the second head, and a second mode for performing printing having higher color reproducibility than the first mode. The control device: In the printing in the first mode, ink is ejected from each of the first head and the second head to perform printing. In the printing in the second mode, the first head and the second head share the work at a predetermined ratio, and the ink is ejected from each head in one reciprocating movement to perform printing in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode. The storage device stores the measured value and the median value of the ink flow path in the first head measured during the manufacture of the first head, and the measured value and the median value of the ink flow path in the second head measured during the manufacture of the second head. In the printing in the second mode, when the measured value of the flow path of the first head is closer to the median value than the measured value of the flow path of the second head, the control device selects the first head as the head with a higher ratio of responsibility for the ink. When the measured value of the flow path of the second head is closer to the median value than the measured value of the flow path of the first head, the control device executes a second selection process of selecting the second head as the head with a higher ratio of responsibility for the ink. A printing apparatus.

6. A first head having nozzles for ejecting ink. A second head having nozzles for ejecting ink of the same color as the first head. A carriage that supports the first head and the second head and is capable of reciprocating movement. A storage device. A control device, and is provided with In the printing of an image, there are a first mode of printing with the first head and the second head, and a second mode for performing printing having higher color reproducibility than the first mode. The control device In the printing in the first mode, ink is ejected from each of the first head and the second head to perform printing. In the printing in the second mode, the first head and the second head share the work at a predetermined ratio, and the ink is ejected from each head in one reciprocating movement to perform printing in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode. An ink tank. A first ink tube that is a flow path of the ink between the ink tank and the first head. A second ink tube that is a flow path of the ink between the ink tank and the second head. A medium conveyance mechanism that conveys the print medium in a sub-scanning direction that intersects the main scanning direction, which is the moving direction of the carriage, toward the discharge port, and discharges the print medium from the discharge port; further comprising; the first head and the second head are arranged so as to be shifted in the sub-scanning direction with a part thereof overlapping; the storage device stores priorities based on the arrangements of the first head and the second head; the control device executes a responsibility ratio setting process for setting the responsibility ratio of the ink discharged by each of the first head and the second head with respect to the density of dots constituting an image in the second mode, and based on the height of the priority, executes a third selection process for selecting, from the first head and the second head, the head having a higher responsibility ratio of the ink as the responsibility ratio in the responsibility ratio setting process. A printing apparatus.

7. In the third selection process, the control device selects, as the head having a higher responsibility ratio of the ink, the head corresponding to the shorter ink tube among the first ink tube and the second ink tube from among the first head and the second head. The printing apparatus according to claim 6.

8. In the third selection process, the control device selects, as the head having a higher responsibility ratio of the ink, the head located on the downstream side when the carriage moves in the main scanning direction from the standby position from among the first head and the second head. The printing apparatus according to claim 6.

9. In the third selection process, the control device selects, as the head having a higher responsibility ratio of the ink, the head closer to the discharge port from among the first head and the second head. The printing apparatus according to claim 6.

10. a first head having nozzles for discharging ink; a second head having nozzles for discharging ink of the same color as the first head; a carriage that supports the first head and the second head and is capable of reciprocating movement; a storage device; a control device, and has a first mode and a second mode for executing printing having higher color reproducibility than the first mode as modes for printing an image with the first head and the second head; the control device In the printing in the first mode, ink is ejected from each of the first head and the second head to perform printing. In the printing in the second mode, the first head and the second head share the work in a predetermined ratio, and in one reciprocating movement, the ink is ejected from each head, and printing is performed in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode. The control device stores, as usage history, in the storage device the history of the number of executions of the cleaning process of the first head, the history of the number of executions of the cleaning process of the second head, the information on the elapsed time after the replacement of the first head, the information on the elapsed time after the replacement of the second head, the information on the total ejection amount of the ink in the first head, and the information on the total ejection amount of the ink in the second head. The printing apparatus, wherein the control device executes a fourth selection process of selecting, as the head with a higher ink share ratio, any one of the first head and the second head that has a smaller number of executions of the cleaning process, a smaller elapsed time, or a smaller total ejection amount.

11. The control device, in the fourth selection process, compares the number of cleaning times of the first head and the second head with a predetermined threshold value from the usage history, and selects, as the head with a higher ink share ratio, the head among the first head and the second head whose number of cleaning times does not exceed the threshold value. The printing apparatus according to claim 10.

12. The control device, in the fourth selection process, selects, as the head with a higher ink share ratio, the head with a shorter elapsed time among the first head and the second head from the usage history. The printing apparatus according to claim 10.

13. The control device, in the fourth selection process, selects, as the head with a higher ink share ratio, the head with a smaller total ejection amount of the ink among the first head and the second head from the usage history. The printing apparatus according to claim 10.

14. The control device, in the printing in the second mode, makes the share ratios of the first head and the second head different between the first head and the second head. The printing apparatus according to any one of claims 1 to 13.

15. A first head having nozzles for ejecting ink, A second head having nozzles that eject ink of the same color as the first head, A carriage that supports the first head and the second head and is capable of reciprocating movement, A printing method using a printing apparatus including a storage device that stores nozzle characteristic information indicating the ink ejection characteristics of the nozzles, the method comprising: Setting to any one of a first mode and a second mode for performing printing having higher color reproducibility than the first mode when printing an image, In a state where the first mode is set, ejecting the ink from each of the first head and the second head to perform printing, and in a state where the second mode is set, the first head and the second head are shared at a predetermined share ratio, and the ink is ejected from each head in one reciprocating movement to perform printing in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode, Performing a share ratio setting process for setting the share ratio of the ink ejected by each of the first head and the second head with respect to the density of dots constituting an image in the second mode, and based on the nozzle characteristic information, performing a first selection process for selecting, from the first head and the second head, the head having a higher share ratio as the share ratio of the ink in the share ratio setting process, A printing method.

16. A first head having nozzles that eject ink, A second head having nozzles that eject ink of the same color as the first head, A carriage that supports the first head and the second head and is capable of reciprocating movement, A printing program for causing a computer in a printing apparatus including a storage device that stores nozzle characteristic information indicating the ink ejection characteristics of the nozzles to execute, the program causing the computer to: An operation mode setting unit that sets the computer to any one of a first mode and a second mode for performing printing having higher color reproducibility than the first mode when printing an image, In the state set to the first mode, ink is ejected from each of the first head and the second head to execute printing. In the state set to the second mode, the first head and the second head share the work in a predetermined share ratio, and in one reciprocating movement, the ink is ejected from each head, and printing is executed in a range narrower than the range in which printing is completed in one reciprocating movement in the first mode. A printing execution unit, and In the second mode, it functions as a share ratio setting unit that sets the share ratio of the ink ejected from each of the first head and the second head with respect to the density of the dots constituting the image. When setting the share ratio of the ink, the share ratio setting unit selects the head with the higher share ratio from the first head and the second head based on the nozzle characteristic information. Printing program.

Images