JP2011189729A - Recording apparatus and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording apparatus capable of obscuring defective printing caused by color banding. <P>SOLUTION: In this method, a print head using nozzle range is divided into a plurality of blocks in bidirectional printing, and the upper and lower blocks complement each other. In the method, printing rates of the upper and lower blocks are each weighted differently for color heads. Thus, bidirectional color banding can be suppressed while suppressing reduction in the printing speed to minimum. When providing an uneven region in a print mask function of a color swath is employed in combination, boundary banding and beading can be suppressed at the same time. Thus, stable achievement of high printing quality can be expected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a recording apparatus and a recording method for printing by controlling the operation of a print head. In particular, the present invention relates to an ink jet recording apparatus and a recording method.

  In a recording apparatus typified by an ink jet printer, high image quality is a major point that affects its performance as well as high printing speed. In order to achieve high image quality, it is necessary to land droplets ejected from the print head accurately and uniformly on a predetermined position on the paper. In particular, in the case of a color printer, it is important to improve the landing accuracy in order to prevent a so-called color misregistration problem that the hue is changed by shifting the landing position of each color.

  However, when bi-directional printing is performed, the order in which dots are ejected and landed from each color print head in the forward pass and the return pass is switched depending on the print head arrangement order. There is a problem that so-called bidirectional color banding occurs.

  For example, Japanese Patent No. 3896329 discloses a drawing operation based on a color swath to which a non-uniform print mask function is applied, which lowers the probability of use of nozzles corresponding to the peripheral region of the end compared to other nozzles. A technique for making bidirectional color banding less noticeable is disclosed.

Japanese Patent No. 3896329

  As described above, the cause of the bi-directional color banding can be said that the color overlapping order differs between the forward path and the return path. As shown in FIG. 4, the arrangement of the color heads arranged in a horizontal line is called an inline arrangement. In this case, the forward scan is K (black), C (cyan), M (magenta), Y (yellow). Ink colors are ejected in this order, and the color inks overlap in that order. In the backward scan, ink colors are ejected in the order of Y, M, C, and K, and the respective color inks are overlapped in that order. That is, the ink color stacking order is opposite between the forward pass and the return pass. Among them, the contribution ratio of the first scan (first scan) and the last scan (final scan) that are first drawn on the paper is high. The former is explained by the fact that the ink ejected on the paper for the first time spreads in a short time and forms large dots, and the ink ejected later forms a slightly smaller dot on the spread ink. it can. That is, the influence of the color that is ejected first in the first scan and the color of the print head that is located in the front in the carriage traveling direction is strong. For the latter, the influence of this color is strong because the print head color located at the end of the final scan, that is, the rear of the carriage traveling direction is at the top of the print surface. An example of typical bidirectional color banding is shown in FIG. FIG. 3A shows a proper image.

  Bidirectional color banding may also occur between the left and right edges of the print area. Even within an area where the order of color overlap is the same, the time difference between the forward path and the backward path is large near the origin in the main scanning direction (direction in which the carriage scans). In other words, it takes time to draw at the beginning of the outbound trip and at the end of the return trip. On the other hand, at the end opposite to the origin, the time difference drawn from the forward path to the return path is small. This time difference causes a difference in the dry state of the dots on the paper in the immediately preceding scan, so that the nature of the ink ejected thereon naturally changes. In other words, color banding occurs due to the time difference.

  When printing a large poster or advertising material, there is a technique called tiling that arranges a plurality of small printed materials horizontally to make a large printed material. When there is color banding at the left and right ends, when tiling, the color difference between the joints of the printed matter becomes conspicuous, and the image quality may be significantly reduced.

  In Japanese Patent No. 3896329, a non-uniform print mask function is applied to color swaths for dark ink colors (for example, C, M, K), and a uniform print mask function is applied to light ink colors (for example, Y). Two-way color banding is less noticeable. However, this is only reduced, and bidirectional color banding may still be noticeable depending on the hue and density of the image to be drawn.

  In addition, by applying a non-uniform print mask function, when attention is paid to a certain scan, the difference in nozzle use probability increases near the non-uniform end of the color swath. This is nothing but a difference between the drawing process for forming dots in a certain area and the drawing process for forming dots in another area. This is the same as the cause of the color banding due to the time difference between the left and right ends. This is more conspicuous when the print mask function uses a polygonal line or S-shaped gradation curve and has a steep slope such as 0% to 100% or 100% to 0%. Color banding corresponding to the gradation curve constituting the non-uniform print mask function will occur. This suggests the possibility of deteriorating the image quality.

  Further, in the color swath, a difference between the non-uniform portion of the print mask function and the uniform portion may appear as color banding. This is because the non-uniform upper and lower areas of the print mask function complement each other and form a dot for one conventional scan, so the uniform print mask function scans more than the area drawn by all scans. The number will increase. That is, a difference occurs in the time until the image is completed. This difference is exactly the cause of the color banding because it is different between the drawing process for forming dots in one area and the drawing process for forming dots in another area.

  For bidirectional color banding, instead of bidirectional printing, unidirectional printing is performed, so that the overlapping order of ink colors and the time difference can be unified over the entire drawing area. This reduces color banding, but is not practical because the printing speed is reduced by a factor of 1/2 compared to bidirectional printing. In addition, in unidirectional printing, image quality defects due to specific vibrations on the carriage travel path are accumulated every scan, which may lead to image quality defects such as vertical stripes and color unevenness.

  In addition, by mounting two or more print heads for each color so that the colors are arranged symmetrically on the carriage, it is possible to unify the color stacking order regardless of the forward or backward path. Since a double or more head is required, the cost increases such as an increase in the size and weight of the carriage and an increase in the size of an actuator for driving the carriage.

  In addition, there is a technique called full stagger arrangement in which the arrangement of the color heads on the carriage is not completely overlapped in the paper feed direction. An example of this is shown in FIG. In this case, the ink color drawn on the sheet for the first time is always K, and after a plurality of scans, drawing of C starts after drawing with K is completely completed. Similarly, Y is drawn after M and M are finished after drawing by C is completed, so the ink color superposition order is K, C, M, Y at any location on the paper. It is common in the order. The full staggered arrangement can prevent the occurrence of bidirectional color banding, but it has problems such as an increase in the platen width, an increase in the carriage size, and an accompanying increase in the carriage drive system. It ’s hard.

  As a method for reducing the carriage size compared to the full staggered arrangement, there is a technique called a semi-staggered arrangement. An example of this is shown in FIG. Although each color head is not completely shifted in the paper feed direction, the ink color having a high contribution rate can be fixed in the first scan and the final scan. The smaller the overlapping area of each color head, the closer to the full stagger arrangement, and the more the overlapping area, the closer to the inline arrangement. Of course, the closer to the full staggered arrangement, the more the bi-directional color banding can be suppressed, but the disadvantage of the larger carriage cannot be excluded.

  In addition, there is a method of limiting the number of nozzles used for each color head as a method of providing a semi-stagger effect while being in-line arrangement. An example of this is shown in FIG. In this example, the use nozzle width of each color head is divided into seven, and four blocks are used in one scan. In FIG. 7, the filled portion is the used nozzle range. The blocks to be used are shifted by one block for each color. As a result, it is possible to provide an effect as if a staggered arrangement was achieved while being inlined, and bi-directional color banding can be suppressed. However, on the other hand, since the number of used nozzles is limited, the printing speed is reduced. This becomes more conspicuous as the number of nozzles used in each color head is limited, and as a result, the printing speed is reduced in exchange for the effect of suppressing bidirectional color banding.

  The present invention has been made in view of such circumstances, and a recording apparatus and a recording method capable of making color banding during bidirectional printing in a recording apparatus inconspicuous without reducing productivity as much as possible from the conventional printing mode. The purpose is to provide.

  In the recording apparatus of the present invention, a print head that is divided into a plurality of blocks having the same width of the used nozzle range and in which ink ejection is controlled for each block is arranged for each of a plurality of ink colors, and the print head is scanned. In a recording apparatus that forms a color image by ejecting ink onto a recording medium, each color swath in the formation of the color image has a relationship of complementing each other by at least one block above and below the end of the print head, and the top and bottom The control means for controlling the desired ink color to be emphasized in the first and final scans in the multi-pass printing in the same way in the entire drawing area by giving different weights to the printing ratio of each block. It is characterized by having.

  Further, according to the recording method of the present invention, a print head that is divided into a plurality of blocks having the same width of the used nozzle range and in which ink ejection is controlled is arranged for each of the plurality of ink colors, and the print head is scanned. In the recording method of the recording apparatus for forming a color image by ejecting ink onto the recording medium, each color swath in the color image is a mask that complements each other by at least one block above and below the end of the print head, In addition, the printing rate of each block above and below is obtained by drawing all desired ink colors to be emphasized in the step of obtaining a mask with different weights for each ink color and in the first scan and the final scan in multi-pass printing. And printing the same in the area.

  According to the present invention, it is possible to suppress printing defects such as bidirectional banding caused by the difference in the color overlapping order between the forward pass and the return pass without reducing productivity from the conventional print mode.

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention. FIG. 2 is a schematic view of the carriage mechanism. FIG. 3A is a diagram illustrating an example of an appropriate image. FIG. 3B is a diagram illustrating an example of bidirectional color banding. FIG. 4 is a diagram showing an example in which the heads on the carriage are arranged in-line. FIG. 5 is a diagram showing an example in which the heads on the carriage are arranged in a full staggered manner. FIG. 6 is a diagram showing an example in which the heads on the carriage are arranged in a semi-staggered manner. FIG. 7 is a diagram illustrating an example in which the effect of the semi-staggered arrangement is provided while maintaining the in-line arrangement. FIG. 8 is a diagram illustrating an example in which the effect of the semi-stagger arrangement is more efficiently provided with the in-line arrangement. FIG. 9 is a diagram showing the principle of printing in the printing mode that can suppress the occurrence of boundary banding and beading while maintaining the effect of the semi-stagger arrangement more efficiently with the in-line arrangement. FIG. 10 is a diagram illustrating the principle of printing in the print mode that can suppress the occurrence of boundary banding and beading while providing the effect of semi-stagger placement more efficiently than the method shown in FIG. FIG. 11 is a flowchart for explaining the operation of the embodiment of the present invention.

  Hereinafter, a recording apparatus and a recording method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. In this figure, the recording apparatus 1 is an ink jet printer. The recording apparatus 1 includes a control unit 20 that controls the operation of the entire apparatus. The control unit 20 includes a CPU 21 of a control unit that performs overall control of processing operations in the control unit 20, a ROM 22 of a storage unit in which programs for performing various controls and printing operations of the recording apparatus 1, and the execution of the printing operation are performed. The RAM 23 of the storage means used as a working storage area by each control unit, the EEPROM 24 of the storage means configured by a non-volatile memory for storing setting values and data immediately before the power is turned off, and the state operated in the operation panel 44 are read. At the same time, the operation panel control unit 25 that displays information on the display unit included in the operation panel 44, the print control unit 26 that is a control unit that controls the print operation by the print head 41 with respect to the recording medium, and the operation of the carriage mechanism 42 are performed. From a carriage control unit 27 as a control means for controlling, a grid roller or the like for conveying a sheet as a recording medium A sheet conveyance control unit 28 that is a control unit that controls the operation of the sheet conveyance mechanism 43, an image memory 30 that stores an image to be printed, and a control unit that is a control unit that performs writing / reading control on the image memory 30 31, a host I / F unit 29 which is an interface for inputting / outputting image data and control commands to / from a host computer.

  The print control unit 26 and the carriage control unit 27 control the printing operation while coordinating the print positions based on the carriage position read by the linear encoder 45.

  FIG. 2 is a schematic view of an example constituting the carriage mechanism. The carriage mechanism 42 is provided with means for detecting the position of the print head 41. When ejecting droplets from the print head 41 in the recording apparatus 1, a linear encoder 45 incorporating a scale sensor attached to the carriage 420 and a linear scale 421 fixed along the traveling path of the carriage 420 are used. The current position during the reciprocation of the carriage 420 is detected, and information is input to the control unit 20. The control unit 20 recognizes the position of the print head 41 and generates ink ejection timing, thereby improving the positional accuracy of the droplets that have landed on the paper 422. In this example, four color print heads are mounted in the order of K (black), C (cyan), M (magenta), and Y (yellow) from the left side when viewed from the paper 422 feeding direction, that is, from the head in the forward direction. . In the forward direction, the ink color is formed on the recording medium 422 in this order, and the reverse is the reverse direction.

  Ink jet printers using these configurations require multiple scans and bi-directional carriage scans in order to suppress the deflection and omission of the nozzles of the print head 41 and periodic unevenness caused by vibration of the drive system. Usually, a certain area is drawn. This is generally called multipass printing. In multi-pass printing in which an image of a certain area is completed by n scans, the number of dots ejected in one scan is 1 / n with respect to the total dots constituting a certain area. For example, in a standard printing mode called 4-pass that completes an image in 4 scans, a quarter of dots forming a certain area are ejected for each scan, and the image is printed by conveying the paper 422 each time. I will complete it. In this case, the conveyance pitch of the paper 422 is approximately ¼ of the color swath constituted by the total number of nozzles of the print head 41.

  Next, a printing mode according to an embodiment of the present invention will be described with reference to FIG. Although the standard printing mode called four-pass, in which an image is completed in four scans, is used as a base, the used nozzle width is equally divided into five as shown by the blocks 50, 51, 52, 53, and 54. Of these, the upper and lower blocks, that is, the block 50 and the block 54, complement each other, so that the conventional image printing rate for four passes is obtained. In other words, the K color head complements the block 54 at 0% and the block 50 at 100%, the C color head complements at the block 54 at 30%, the block 50 at the 70% complement, and the M color head at the block 54 70%. %, The block 50 is complemented by 30%, the Y color head is complemented by 100% for the block 54, and the block 50 is complemented by 0%. This is nothing other than changing the printing ratio of each color of the first scan and the final scan, and emphasizing the dominant ink color in each scan in the entire drawing area. That is, for the first scan, the K color ink is dominant for both the forward path and the backward path, and for the final scan, the Y color ink is dominant for both the forward path and the backward path. Thus, as shown in FIG. 8, it is more efficient than the method of giving the semi-stagger effect by limiting the number of nozzles used in the head (printing speed is 4/7 times of 4 passes) (printing speed is 4/4 of 4 passes). Bidirectional color banding can be suppressed to 5 times. Of course, the printing rate of the upper and lower blocks of each color may be appropriately changed according to the medium used and the drawing image. These print ratios may be uniform in the upper and lower blocks, but a gradation curve may be provided in the paper feed direction, and a non-uniform print mask function based on this may be used. Thereby, image quality defects such as boundary banding and beading can be suppressed.

  The print head has a plurality of nozzles, and whether or not ink is ejected from the nozzles is determined by a mask. For this mask, the relationship between the position of the nozzle and whether or not the nozzle can be used is a print mask function. The print mask function is stored in advance in the storage means, read out as necessary, and based on the print mask function. Calculate and determine the mask.

  Non-uniform print mask functions include, for example, those that determine whether or not to use nozzles at random, and those that vary the probability distribution to use depending on the position of the nozzles. A uniform thing is what fixed the probability of using a nozzle, such as 50%, etc., for example.

  Next, a printing mode according to an embodiment in which the effect of the semi-stagger arrangement can be expected will be described with reference to FIG. The used nozzle width is equally divided into six as indicated by the blocks 60, 61, 62, 63, 64, and 65. Of these, the upper and lower two blocks, that is, the block 60 and the block 64, and the block 61 and the block 65 complement each other, so that the conventional image printing rate for four passes is obtained. The same applies to the weights of the upper and lower blocks of each color. Blocks 64 and 65 are complemented by 0% and blocks 60 and 61 are complemented by 100% in the K-color head, and blocks 64 and 65 are complemented by 30% and blocks 60 and 61 in the C-color head. 70% for M color heads, 70% for blocks 64 and 65, 30% for blocks 60 and 61, 100% for blocks 64 and 65 for Y color head, 0 for blocks 60 and 61 % Complement each other. This makes it possible to coordinate dominant ink colors not only for the first scan and the final scan, but also for the second scan and the scan before the final scan. Furthermore, the printing speed is 4/6 times that of 4 passes, which is more efficient than the method shown in FIG. Of course, a non-uniform print mask function may be used for each of the upper and lower blocks.

  Furthermore, a method as shown in FIG. 10 is also conceivable. In this case, the used nozzle width is equally divided into eight, and each of the upper and lower four blocks complements each other. There is nothing other than a full stagger arrangement between K and Y, and the probability of using the nozzles of blocks 70 to 73 and blocks 74 to 77 is 100%, respectively, and the probability of using the nozzles of the blocks that are complementary to this is 0. %. C is 70% for blocks 70 to 73, 30% for blocks 74 to 77, and M has an inverse relationship with C. As a result, the effect of semi-stagger placement can be provided.

  Further, in the example of FIG. 10, an image quality improvement effect can be considered by changing the use probability of the nozzles in each block of the forward path and the backward path. In drawing, this is the first ink color that is ejected to the surface of the media, that is, the ink color that is arranged at the beginning of the carriage movement direction of the first scan, or the last ink color that is ejected, that is, at the end of the carriage movement direction of the last scan. Regarding the arranged ink colors, attention is paid to the fact that the contribution ratio of some image quality failure to the printed product finally completed is high. More specifically, the first ink that is ejected on the surface of the media is different from the ink that is ejected on the subsequent ink, and it is possible that the dots spread widely on the surface of the highly wettable media. Since the ink ejected last is located at the top of the ink layer ejected so far, the influence of the color is great. The two phenomena described here have different effects depending on the type of media used. Therefore, the way of changing the probability of using the nozzles of each block in the forward path and the return path varies depending on which influence is reduced. For example, if it is desired to reduce the influence of the latter, the probability of nozzles used by each block is adjusted for the M and Y heads located rearward for the forward path and for the K and C heads for the backward path. That is, for the forward path, the M blocks 70 to 73 are changed from 30% to 40%, the blocks 74 to 77 are changed from 70% to 60%, the Y blocks 70 to 73 are changed from 0% to 10%, and the blocks 74 to 77 are changed. Are changed from 100% to 90%, respectively. On the other hand, on the return path, K blocks 70 to 73 are changed from 100% to 90%, blocks 74 to 77 are changed from 0% to 10%, C blocks 70 to 73 are changed from 70% to 60%, and blocks 74 are changed. 77 is changed from 30% to 40%. As a result, the influence of the ink color located at the top of the ink layer can be reduced. Conversely, in order to reduce the influence of the ink color ejected on the media surface for the first time, the color swath may be designed based on the opposite idea.

  As described above, in the method of dividing the used nozzle range of the print head into a plurality of blocks and complementing each other by the upper and lower blocks, by giving different weights to the print rates of the upper and lower blocks for each color head, the first scan and Ink colors that are desired to be emphasized in the final scan can be made the same in all drawing areas. Although there is a slight decrease in printing speed as compared with the standard printing mode, it can be expected that the printing speed is slower and the image quality is improved in the same way as when the number of nozzles used is limited to provide the effect of semi-stagger arrangement. That is, by allowing the user to select a plurality of printing modes based on a basic four-pass printing mode (referred to as a standard printing mode) and capable of selecting the effect of suppressing color banding according to the printing speed described so far. Therefore, it is possible to realize a combination of printing speed and printing image quality according to the user's application. For example, the printing mode described with reference to FIGS. 8 to 10 is referred to as a “pseudo stagger mode”, and weights 1 to 3 are set in advance. If you want to output printed matter that does not place much emphasis on image quality, it is better to select “pseudo stagger mode 1”, which has a high printing rate per scan and increases the printing speed as much as possible. When output is desired, the printing rate per scan is low, “pseudo stagger mode 3” is selected, and high image quality can be obtained even if productivity is lowered. To balance these, “pseudo stagger mode 2” may be selected. For example, a flag corresponding to the print mode is stored in the RAM 23, and a mask and a transport pitch are selected according to the flag, and printing is performed. The flag can be changed by an input on the operation panel 44, or can be changed in accordance with a predetermined condition.

  Further, the printing rate of each block used for the recording medium to be used in advance is stored in the EEPROM 24, and when the recording medium is used, the printing rate is read and set to each block, so that the printing rate can be appropriately set according to the recording medium. Can print. Specifically, after the recording medium is set, the recording medium set from the operation panel 44 is selected, the printing rate of each block corresponding to the selected recording medium is acquired from the EEPROM 24, and a mask to be used for each block is set. The The print rate may be a constant print rate depending on the recording medium, but the print mask function constituting the probability distribution of the nozzles used may be non-uniform.

  The operation for drawing one line in the print mode shown in FIG. 8 will be described in more detail using a flowchart. FIG. 11 is a flowchart for explaining the operation of the embodiment of the present invention.

  In accordance with the program stored in the ROM 22, the CPU 21 performs various calculations and controls, and the recording apparatus 1 performs a drawing operation.

  First, a mask is selected and applied for each block to the recording head corresponding to each ink color according to the print mode (step S1). This is because printing is performed using an appropriate mask for each block of the recording head in accordance with the printing mode. The mask selects whether or not the nozzles of the recording head are used. Based on this mask and image data stored in the image memory 30, ink is ejected from the nozzles. The mask is generated based on a print mask function configured by a probability distribution in which the nozzles of the recording head are used. For example, for a non-uniform print mask function, a probability distribution of nozzles is used such that the printing rate decreases as the end of the swath is approached, and the probability distribution of nozzles used so that the printing rate increases as the distance increases. What is comprised is typical. In another example of the print mask function, the probability distribution in which the nozzles are used is randomly configured. By printing using a mask to which such a print mask function is applied, an output image having a dot distribution based on the print mask function can be obtained. When using such a mask, for example, the print head is divided into a plurality of blocks, and the mask is configured so that the images drawn for each block on the upper and lower sides of the edge are respectively complemented. It is possible to draw so that the dot is not missing by one block at the top and bottom.

  Here, the use nozzle width is equally divided into five as indicated by the blocks 50, 51, 52, 53, and 54. Of these, the upper and lower blocks at the end, that is, the block 50 and the block 54, complement each other, so that the conventional image printing rate for four passes is obtained. In other words, the K color head complements the block 54 at 0% and the block 50 at 100%, the C color head complements at the block 54 at 30%, the block 50 at the 70% complement, and the M color head at the block 54 70%. %, The block 50 complements at 30%, and the Y color head complements at block 54 at 100% and block 50 at 0%. In this way, the weighting of the upper and lower blocks at the end is changed according to each color. This value is previously determined and stored in the EEPROM 24, and is read and used. This value can be set to a different value depending on the printing mode such as the storage medium to be used and the type of desired image quality.

  Next, it is determined whether or not it is the first scan. If it is the first scan, the process proceeds to step S3, and if not, the process proceeds to step S4 (step S2).

  In step S3, the first scan is printed (step S3). In the first scan, printing is performed in the order of K, C, M, and Y, which is the arrangement order of the print heads. When printing is completed, the process proceeds to step S11, and the recording medium is conveyed by the block width of the print head. Then, the process ends and waits for the next scan.

  In step S4, it is determined whether or not it is the second scan. If it is the second scan, the process proceeds to step S5, and if not, the process proceeds to step S6 (step S4).

  In step S5, the second scan is printed (step S5). The second scan is printed in the order of Y, M, C, K. When printing is completed, the process proceeds to step S11, and the recording medium is conveyed by the block width of the print head. Then, the process ends and waits for the next scan.

  In step S6, it is determined whether or not it is the third scan. If it is the third scan, the process proceeds to step S7, and if not, the process proceeds to step S8 (step S6).

  In step S7, the third scan is printed (step S7). The third scan is printed in the order of K, C, M, Y. When printing is completed, the process proceeds to step S11, and the recording medium is conveyed by the block width of the print head. Then, the process ends and waits for the next scan.

  In step S8, it is determined whether or not it is the fourth scan. If it is the fourth scan, the process proceeds to step S9, and if not, the process proceeds to step S10 (step S8).

  In step S9, the fourth scan is printed (step S9). The fourth scan is printed in the order of Y, M, C, K. When printing is completed, the process proceeds to step S11, and the recording medium is conveyed by the block width of the print head. Then, the process ends and waits for the next scan.

  In step S10, the fifth scan is printed (step S10). The fifth scan is printed in the order of K, C, M, Y. When printing is completed, the process proceeds to step S11, and the recording medium is conveyed by the block width of the print head. Then, the process ends and waits for the next scan.

In step 11, the recording medium is conveyed by the block width of the print head, the process is terminated, and the next scan is awaited.
Color swath printing for the width of 4 blocks is completed in 5 scans.

  By printing in this way, the printing rate of each color of the first scan and the final scan can be changed, and the dominant ink color in each scan can be emphasized and printed in the entire drawing area. That is, for the first scan, the K color ink is dominant for both the forward path and the backward path, and for the final scan, the Y color ink is dominant for both the forward path and the backward path.

  As described above, in the method of dividing the nozzle range of the print head into a plurality of blocks for bi-directional printing and complementing each other by the upper and lower blocks, the printing ratio of the upper and lower blocks should be given different weights for each color head Thus, bidirectional color banding can be suppressed while minimizing the decrease in printing speed. In addition, boundary banding and beading can be simultaneously suppressed by using a non-uniform region in the color swath print mask function. As a result, it can be expected to stably achieve high print image quality.

DESCRIPTION OF SYMBOLS 1 ... Recording device, 20 ... Control part, 21 ... CPU, 22 ... ROM, 23 ... RAM, 24 ... EEPROM, 25 ... Operation panel control part, 26 ... Print control unit, 27 ... carriage control unit, 28 ... paper conveyance control unit, 29 ... host I / F unit, 30 ... image memory, 31 ... image memory write / read control unit , 41 ... print head, 42 ... carriage mechanism, 43 ... paper transport mechanism, 44 ... operation panel, 45 ... linear encoder

Claims (5)

A print head that is divided into a plurality of blocks having the same width of the used nozzle range and in which ink ejection is controlled is arranged for each of the plurality of ink colors, and ink is ejected onto a recording medium while scanning the print head. In a recording apparatus for forming a color image
Each color swath in the formation of the color image has a relationship of complementing each other by at least one block above and below the end of the print head, and the printing rate of each block above and below has a different weight for each ink color. Thus, a recording apparatus comprising control means for controlling the desired ink color to be emphasized in the first drawing and the final scan in multi-pass printing in the same manner in the entire drawing area.   The block is drawn by applying a predetermined print mask function when drawing for the width of the used nozzle range by reciprocation equal to the number of divisions of the print head. The recording apparatus according to 1.   The recording apparatus according to claim 2, wherein a print mask function to be applied to the block is determined in advance according to a type of the recording medium.   The recording apparatus according to claim 2, wherein the print mask function applied to the block is different according to a forward path and a return path in the multipass printing. A print head that is divided into a plurality of blocks having the same width of the used nozzle range and in which ink ejection is controlled is arranged for each of the plurality of ink colors, and ink is ejected onto a recording medium while scanning the print head. In a recording method of a recording apparatus for forming a color image,
Each color swath in the color image is a mask that complements each other by at least one block above and below the end of the print head, and the printing rate of each block above and below is a mask with different weights for each ink color A process of obtaining
And a step of printing the same desired ink color to be emphasized in the entire drawing area in each of the first scan and the final scan in multi-pass printing.