JP5700986B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to an image processing apparatus for processing image data corresponding to the same area for recording an image in the same area by moving the recording means (recording head) relative to the same area of the recording medium a plurality of times. The present invention relates to an image processing method.

  In a serial type ink jet recording apparatus, a multi-pass recording method in which the same area of a recording medium is recorded by a plurality of recording scans of a recording head is useful in order to improve the uniformity of a recorded image. However, even if the multi-pass printing method is adopted, image defects such as misalignment and uneven density occur between the dot recording position in the preceding recording scan and the dot recording position in the subsequent recording scan due to the conveyance error of the recording medium. There is a case.

  FIGS. 1A and 1B are schematic diagrams for explaining the above-described image adverse effects when two-pass multi-pass printing is performed. In the figure, black circles indicate dots recorded by the first recording scan, and white circles indicate dots recorded by the second recording scan. Conventionally, in the multi-pass printing method, the same area is printed using mask patterns that are complementary to each other in multiple printing scans of the printing head. Therefore, a dot arrangement as shown in FIG. 1A is obtained in the same area on the recording medium.

  However, when the dot group recorded in the first recording scan and the dot group recorded in the second recording scan are shifted for some reason, the dot arrangement on the recording medium is as shown in FIG. . That is, the dot group recorded in the first recording scan and the dot group recorded in the second recording scan are overlapped with each other, and the blank area is exposed by that amount, so that the dot coverage on the recording medium, that is, the image density is lowered. . If such a recording position shift suddenly occurs due to fluctuations in the conveyance amount of the recording medium, fluctuations in the carriage speed, fluctuations in the distance between the recording medium and the recording head (inter-paper distance), etc., the density only at that location. A region with a low density appears and is recognized as uneven density.

  In Patent Document 1, as a technique for reducing such image adverse effects, image data is distributed so as to correspond to different printing scans at a multi-value stage before binarization, and the multi-value image data after distribution is distributed. A method for binarizing each of them is disclosed.

  FIGS. 2A and 2B are schematic diagrams showing dot recording positions when 2-pass multi-pass printing is performed using the method of Patent Document 1. FIG. In the figure, black circles are dots recorded by the first recording scan, white circles are dots recorded by the second recording scan, and hatched circles are superimposed by the first recording scan and the second recording scan. Duplicate dots. In the method of Patent Document 1, since multi-valued image data is distributed so as to correspond to the recording scan and binarized without correlation, the dot group recorded in the first recording scan and the second group are recorded. The dot group recorded by the recording scan is not complementary. That is, some pixels record dots in both the first recording scan and the second recording scan, and some pixels do not record dots from either the first recording scan or the second recording scan.

  According to such a dot arrangement, even if the dot group recorded in the first recording scan and the dot group recorded in the second recording scan are shifted, as shown in FIG. The dot coverage does not vary much. Although a portion where the dots recorded by the first recording scan and the dots recorded by the second recording scan overlap newly appears, there is also a portion where the region where the two dots are originally overlapped does not overlap. It is.

  However, such density fluctuations due to printing position shifts between printing scans are not so conspicuous in low density areas where the number of dots recorded on the printing medium is originally small. In the low density portion, the dot group recorded by the first recording scan and the dot group recorded by the second recording scan are originally sparse, and even if these dot groups slightly deviate, they overlap or separate from each other. This is because the distance between the dots is not so close. On the contrary, in the low density portion, there is a case where the density of the dots is biased by adopting the method of Patent Document 1, and the accompanying graininess is regarded as a problem.

  In such a situation, in Patent Document 2, after multi-valued image data is distributed to a plurality corresponding to the recording scan, the low density portion is binarized so as to be mutually exclusive in each recording scan. A method is disclosed. According to such a method of Patent Document 2, it is possible to perform multi-pass printing that suppresses graininess in a low density portion and suppresses density unevenness due to a recording position shift at medium density or higher.

JP 2000-103088 A JP 2009-246730 A

  By the way, in recent years, with the increase in resolution of a recording apparatus, a method of recording a plurality of dots at different positions in a pixel area for one pixel after quantization has been adopted. Also in Patent Document 2, each of the multi-value data distributed corresponding to two recording scans is quantized to either 0, 1, or 2, and the position and number of dots to be recorded for one level are determined. A method of binarizing the dot pattern as shown in FIG. 3 is disclosed. In the case of FIG. 3, for example, when the level after quantization is 2, dots are recorded one by one at diagonal positions (upper left and lower right positions) of the 2 × 2 area.

  However, in the method of Patent Document 2, a constant dot pattern as shown in FIG. 3 is used for any recording scan, so that density insufficiency occurs in the middle and high density portions, or density due to recording position shift. In some cases, unevenness could not be avoided sufficiently. The reason will be described below.

  In general, the size of dots in a recording medium is designed in association with the recording resolution so that the blank area of the recording medium is sufficiently covered when dots are recorded in all pixels corresponding to the recording resolution of the recording apparatus. ing. As in Patent Document 2, when one pixel for image processing is expressed in gradation corresponding to a 2 × 2 recording resolution area, one dot is recorded in all of the 2 × 2 area (FIG. 4 ( a)) The highest concentration is obtained. However, as in Patent Document 2, in the configuration in which each of the multi-value data is quantized after being distributed, even if the multi-value data before distribution is a signal (255) indicating the highest density, each recording scan is performed. The multi-value data corresponding to is reduced to 50% (128). Then, it is quantized to a gradation value (level 2) in which two dots are recorded in the 2 × 2 area. As a result, according to the dot pattern of FIG. 3, level 2 which is the same gradation value for both the first recording scan and the second recording scan is the diagonal of the 2 × 2 area as shown in FIG. One dot is recorded at each position (upper left and lower right positions). That is, even when the signal (255) indicating the maximum density is input to all the pixels in the same image area, dots are not recorded in all the areas, as shown in FIG. In addition, two dots are recorded overlappingly in every other area. In this case, the number of dots recorded in the 2 × 2 area is equal to the case where one dot is recorded in every 2 × 2 area, but a blank area remains on the recording medium. That is, the density is insufficient as compared with the case where one dot is recorded in every 2 × 2 area.

  In addition, when a recording position shift occurs between the first recording scan and the second recording scan in such a recording state, the dot recording state is as shown in FIG. 4D, and FIG. Compared to the case, the blank area is reduced. That is, with the configuration of Patent Document 2, the graininess in the low density region can be reduced, but insufficient density and uneven density in the middle and high density parts cannot be sufficiently suppressed.

  The present invention has been made to solve the above problems. Therefore, the object is to provide a granularity and density non-uniformity over the entire gradation area from the low density part to the high density part in the case where gradation is expressed with one pixel corresponding to a plurality of areas. It is an object to provide an image recording apparatus and an image recording method capable of outputting such an image.

The present invention for solving the above problems, have rows relative scanning of the run査direction between the recording head for ejecting the recording medium and the ink, at least a first to a given area on the recording medium, first In each of a plurality of scans including two scans , ink is ejected to each of a plurality of pixel areas in the predetermined area to record dots, thereby achieving a first resolution for recording an image in the predetermined area An image processing apparatus for generating corresponding binary recording data based on multi-value image data corresponding to a second resolution lower than the first resolution and corresponding to the predetermined area, By distributing image data, the first multi-value data corresponding to at least the first scan and corresponding to the second resolution, and corresponding to at least the second scan and the first scan. 2 And distribution means for generating a plurality of multi-valued data including a second multi-level data corresponding to the resolution, and the first generated by the distribution means, quantizing each of the second multi-level data Respectively, a quantization means for generating first and second quantized data of M values (M ≧ 2) corresponding to the second resolution , respectively, and corresponding to the first resolution, respectively, Acquisition means for acquiring a plurality of dot patterns for determining the number and position of dots to be recorded in a plurality of pixel areas in the predetermined area according to the value of the quantized data; and the first generated by the quantization means Generating the first recording data for recording in the first scan based on the quantized data and any one of the plurality of dot patterns acquired by the acquiring unit , and the quantizing unit By Generating a generated second quantized data, and one of the plurality of dot patterns obtained by the obtaining means, the second of said recording data for recording at said second scan based on Recording data generating means, wherein the recording data generating means has the plurality of the plurality of the plurality of recorded data generating means when the values of the first and second quantized data generated by the quantizing means are the same predetermined value. The first recording data is generated based on the first dot pattern among the dot patterns, and the second recording data is generated based on the second dot pattern among the plurality of dot patterns. , And at least one first pixel region among the plurality of pixel regions defining dot recording in the second dot pattern is a dot pattern in the first dot pattern. It is a pixel region that determines non-recording, and at least one second pixel region that is different from the first pixel region is a pixel region that determines dot recording in the first dot pattern.

  According to the present invention, even when an image expressing gradation with one pixel corresponding to a plurality of areas is recorded by multipass printing, variation in coverage due to printing position shift in each printing scan is suppressed. Therefore, it is possible to output a uniform image without density unevenness.

(A) And (b) is a schematic diagram explaining the image bad effect of 2 pass printing. (A) And (b) is a schematic diagram which shows the recording position of the dot of patent document 1. FIG. It is a figure which shows the dot pattern of patent document 2. FIG. (A)-(d) is a figure explaining the relationship between the recording position of a dot, and a coverage. It is a perspective view which shows the outline | summary of the recording part of the inkjet recording device of this invention. (A) And (b) is the schematic which observed the recording head from the discharge port surface. FIG. 3 is a block diagram illustrating a configuration of a main part related to control of a recording apparatus. It is a block diagram for demonstrating the image processing in 1st Embodiment. It is a figure which shows the recording state of the level value which a pixel has, and the dot corresponding to this. (A) And (b) is a figure which shows two different dot patterns. It is a figure which shows the recording state of the dot with the recording medium with respect to the same area | region. It is a schematic diagram which shows the correspondence of the binary data corresponding to a band and a band. (A)-(c) is a figure for demonstrating the difference in the recording method when the recording order of the dot pattern with respect to a band is unified, and when it is not unified. (A)-(d) is the figure which showed the other example of the dot pattern. (A) And (b) is a figure which shows the overlapping dot in the case of a recording position shift. It is a block diagram for demonstrating the image processing in 2nd Embodiment. It is a block diagram for demonstrating the image processing in 3rd Embodiment. (A) And (b) is a figure which shows two different tables. (A) And (b) is a figure which shows the contents of mask data and an arrangement pattern. (A)-(c) is a figure which shows the mode of the data conversion in 3rd Embodiment. (A)-(c) is a figure which shows another example of the data conversion in 3rd Embodiment.

  FIG. 5 is a perspective view showing an outline of the recording unit of the printer engine unit of the serial type inkjet recording apparatus according to the embodiment of the present invention. The recording medium P is conveyed in the y direction (sub-scanning direction) in the figure while being guided and supported on the platen 703 by the rotation of the conveying roller 701. The pinch roller 702 is elastically biased with respect to the conveying roller 701 by pressing means such as a spring (not shown). The transport roller 701 and the pinch roller 702 constitute a component of the first transport means on the upstream side in the recording medium transport direction.

  The platen 703 is provided at a recording position opposite to the surface (discharge surface) on which the discharge ports of the inkjet recording head 704 are formed, and supports the back surface of the recording medium P, whereby the surface and the discharge surface of the recording medium P are supported. And maintain a constant distance. The recording medium P that has been transported and recorded on the platen 703 is sandwiched between a rotating discharge roller 705 and a spur 706 that is a rotating body that follows this, and is transported in the A direction, and is discharged from the platen 703. The paper is discharged to a paper tray 707. The discharge roller 705 and the spur 706 are constituent elements of the second transport unit on the downstream side in the recording medium transport direction.

  The recording head 704 is detachably mounted on the carriage 708 in a posture in which the ejection port surface faces the platen 703 or the recording medium P. The carriage 708 is reciprocated along the two guide rails 709 and 710 by the driving force of the carriage motor E0001, and the recording head 704 executes an ink ejection operation corresponding to the recording signal in the process of relative movement with respect to the recording medium. . The direction in which the carriage 708 moves is the x direction that intersects the direction in which the recording medium is conveyed, and is referred to as the main scanning direction. Recording on the recording medium P is performed by alternately repeating main scanning (movement accompanied by recording) of the carriage 708 and the recording head 704 and conveyance (sub-scanning) of the recording medium.

  6A and 6B are schematic views when the recording head 704 is observed from the ejection port formation surface. In the figure, 1201 is a cyan nozzle row (printing element group), 1202 is a magenta nozzle row, 1203 is a yellow nozzle row, and 1204 is a black nozzle row. The width of each nozzle row in the y direction is d, and printing with a width of d is possible by one scan.

  The image recording apparatus according to the present embodiment (also simply referred to as a recording apparatus) performs multi-pass recording, so that an area in which the recording head 704 can record in one recording scan is stepwise by a plurality of recording scans. An image is formed. At this time, the density unevenness due to the variation of individual nozzles can be further reduced by performing a transport operation smaller than the width d of the recording head 704 during each recording scan.

  FIG. 6B shows a layout of ejection openings in the nozzle row 1201 for one color. The nozzle row 1201 includes two discharge port rows 1301 and 1302 arranged in parallel in the x direction. Each ejection port array has 256 ejection ports for ejecting approximately 2 pl of ink droplets arranged at a pitch of 600 dpi in the y direction. Each of these two ejection port arrays has an individual ejection port in the y direction. They are arranged so as to be shifted by a half pitch. With such a configuration, 512 dots can be recorded on the recording medium at a density of 1200 dpi in the y direction by one recording scan of the recording head. The nozzle arrays 1202 to 1204 have the same configuration.

  FIG. 7 is a block diagram showing a configuration of a main part relating to control of the image recording apparatus according to the embodiment of the present invention. In the figure, reference numeral 3000 denotes a control unit (control board), and 3001 denotes an image processing ASIC (dedicated custom LSI). Reference numeral 3002 denotes a DSP (digital signal processor) which has a CPU inside and is in charge of various control processes and various image processes to be described later. A memory 3003 has a program memory 3003a that stores a control program for the CPU of the DSP 3002, a RAM area that stores a program at the time of execution, and a memory area that functions as a work memory that stores image data and the like. The characteristic dot pattern and table parameters of the present invention described below are stored in the memory 3003 in advance. Reference numeral 3004 denotes a printer engine. Here, a printer engine of an ink jet printer that prints a color image using a plurality of color inks is installed. Reference numeral 3005 denotes a USB connector as a port for connecting a digital camera (DSC) 3012. Reference numeral 3006 denotes a connector for connecting the viewer 1011. Reference numeral 3008 denotes a USB hub (USB HUB). When the PD printer 1000 performs printing based on image data from the PC 3010, the data from the PC 3010 is directly passed through and output to the printer engine 3004 via the USB 3021. As a result, the connected PC 3010 can directly perform printing by exchanging data and signals with the printer engine 3004 (functions as a general PC printer). Reference numeral 3009 denotes a power connector which inputs a DC voltage converted from commercial AC by a power source 3019. A PC 3010 is a general personal computer, 3011 is the memory card (PC card) described above, and 3012 is a digital camera (DSC). Note that the exchange of signals between the control unit 3000 and the printer engine 3004 is performed via the USB 3021 or the IEEE 1284 bus 3022 described above.

(First embodiment)
FIG. 8 is a block diagram for explaining image processing performed by the control unit 3000 when performing two-pass multi-pass printing in the first embodiment. The processing shown below is executed by the control unit 3000 using various parameters stored in the memory 3003 in accordance with a program stored in the program memory 3003a.

  The multi-value image data input unit 81 inputs 600 dpi RGB multi-value image data (256 values) from an external device such as a PC 3010. For this input image data (multi-value RGB data), first, in color processing A82, color space conversion processing from the color space of the original image to a color space that can be expressed by the recording device is performed. As a result, 256-value RGB data included in each pixel is converted into 256-value R′G′B ′. In subsequent color processing B, R′G′B ′ is converted into four sets of multi-value image data (CMYK) corresponding to the ink colors (CMYK) used in the printing apparatus. The color processing unit A82 and the color processing unit B83 are provided with a three-dimensional lookup table (LUT) in which 256 input signals and 256 output signal values are associated one-to-one. By using this LUT, three sets of multi-value data are collectively converted into four sets of multi-value data. In the case of a small table that does not have grid points corresponding to all 256-value input signals, for input values that deviate from the table grid point values, output values are calculated by interpolation from the output values of neighboring grid points. May be. The following processing is performed in parallel independently for each of CMYK.

  In the gradation correction process 84, the input signal value (CMYK) is corrected so that the actual density expressed on the recording medium has linearity with respect to the input multi-value signal, and the 256-value signal value (C ′ M′Y′K ′).

  The image data distribution unit 85 converts the 256-value multi-value data (C′M′Y′K ′), the first scan multi-value data (C1, M1, Y1, K1) and the second scan multi-value data (C2). , M2, Y2, K2). In this embodiment, the distribution at this time is performed almost equally, but the distribution is not necessarily equal.

  The first scanning multi-value data (C1, M1, Y1, K1) generated by the image data distribution unit 85 is subjected to quantization processing in the first scanning quantization processing unit 86-1, so that 0 (non- Recording) or 1 (recording). The second scanning multi-value data (C2, M2, Y2, K2) is quantized in the second scanning quantization processing unit 86-2, and is 0 (non-recording) or 1 (recording). Are converted into quantized data B. At this time, non-recording (0) indicates a state in which no dot is recorded in a pixel area of 600 dpi × 600 dpi in the scanning. On the other hand, recording (1) indicates a state in which one dot is recorded in a pixel area of 600 dpi × 600 dpi in the scanning. In this way, multi-value data of two types for each color is quantized to generate eight types of quantized data (binary data) for four colors. In the present embodiment, the quantization method employed in these quantization processing units is a general error diffusion method. At this time, the quantization processing unit for the same ink employs different diffusion matrices in order to appropriately mix pixels in which dots are recorded in two scans and pixels in which dots are recorded only in one scan. Also good.

  The dot arrangement pattern development process 87-1 converts the binary data A of 600 dpi × 600 dpi into binary data A ′ of 600 dpi × 600 dpi × 1200 dpi in the x direction by referring to the dot pattern a prepared in advance. In addition, the dot arrangement pattern development processing 87-2 refers to the dot pattern b different from the dot pattern a, thereby converting the binary data B of 600 dpi × 600 dpi for the second scanning to 2 in the x direction 600 dpi × y direction 1200 dpi. Convert to value data B ′. In this embodiment, as described above, the resolution is doubled only in the y direction (sub-scanning direction).

  FIG. 9 is a diagram illustrating a binary level value A possessed by a 600 dpi × 600 dpi pixel and a dot recording state on a corresponding 600 dpi × 1200 dpi pixel. A black circle indicates a pixel that records one dot at 600 dpi × 1200 dpi. One pixel area of 600 dpi × 600 dpi corresponds to a pixel area of two pixels of 2 pixels in the y direction × 1 pixel in the x direction at 600 dpi × 1200 dpi. Therefore, when the level value of 600 dpi × 600 dpi is 1, there are two positions where dots are recorded as shown in the figure.

  In the present embodiment, the dot pattern is a pattern in which dot recording or non-recording for each pixel of 600 dpi × 1200 dpi is defined for a wider pixel region (for 16 pixels of 600 dpi × 600 dpi).

  FIGS. 10A and 10B are diagrams respectively showing a dot pattern a and a dot pattern b for level 1 in the present embodiment. Each lattice shows one pixel area corresponding to 600 dpi × 600 dpi, and each dot pattern has an area corresponding to 4 pixels × 4 pixels = 16 pixels of 600 dpi × 600 dpi. In the dot pattern a, two types of patterns are alternately arranged every other pixel in the x direction. On the other hand, in the dot pattern b, two types of patterns are alternately arranged every two pixels in the x direction. Thus, in the present embodiment, the dot pattern a and the dot pattern b have different arrangement states. Such a dot pattern is stored in advance in the memory 3003 of the recording apparatus main body.

  Refer to FIG. 8 again. The 600 dpi × 1200 dpi binary data A ′ and B ′ output from the dot arrangement pattern development processing units 87-1 and 87-2 are respectively stored in different areas of the print buffer and recorded by different scans. Specifically, the binary data A ′ output from the dot arrangement pattern development processing unit 87-1 is stored in the upstream area buffer 88-1 of the recording head for the next scan. The recording is performed in the next scan instead of the current scan by the upstream region of the recording head. Also, the binary data B ′ output from the dot arrangement pattern development processing unit 87-2 is stored in the downstream area buffer 88-2 for current scanning, and the current scanning is performed by the downstream area of the recording head. To be recorded. The data recording area in the print buffer and the actual recording state on the recording medium will be described in detail later.

  Here, for example, the binary data A after the quantization process 86-1 is uniformly level 1 and the binary data B after the quantization process 86-2 for the same region is uniformly level 1 think of. In this case, the dot pattern a shown in FIG. 10A is recorded in the same area in the first scan, and the dot pattern b shown in FIG. 10B is recorded in the second scan.

  11 (a) and 11 (b) show the dot pattern on the recording medium when the binary data after the quantization process for the first scan and the second scan for the same region is uniformly level 1. FIG. It is a figure which shows a recording state. In both figures, black circles indicate dots recorded in the first scan, white circles indicate dots recorded in the second scan, and hatched circles indicate overlapping dots recorded in the first and second scans. Each grid shows one pixel area corresponding to 600 dpi × 600 dpi, and each dot is shown with a diameter of about 40 μm. FIG. 11A shows a state in which no recording position deviation occurs between the dot group recorded in the first scan and the dot group recorded in the second scan, and FIG. 11B shows about 20 μm in the y direction. This shows a case where the recording position deviation occurs.

  In FIG. 11A in which no recording position shift has occurred, dots are arranged in each scan according to the dot pattern a and the dot pattern b. On the other hand, in FIG. 11B in which the recording position shift has occurred, the overlapping dots indicated by diagonal lines in FIG. 11A are separated, and the first scanning dots (black circles) and the separated dots are separated from each other. Two scanning dots (white circles) overlap. The number of dots that overlap with such a recording position shift is substantially the same as the number of dots that are separated. As a result, even if both figures are compared, the area covering the recording medium has no recording position deviation (FIG. 11A) and a recording position deviation (FIG. 11 (FIG. 11)). b)) is almost unchanged. That is, according to the present embodiment, different dot patterns a and b as shown in FIGS. 10A and 10B are assigned to the first recording scan and the second recording scan, respectively. Thus, it is possible to output an image that does not invite density unevenness due to a recording position shift. In other words, the dot pattern of the first recording scan and the second recording scan used in this embodiment has a substantially constant coverage area with respect to the recording medium regardless of the recording position shift between the first scan and the second scan. The dot pattern is maintained.

  FIG. 12 shows the correspondence between the band, which is the unit of the image area on the recording medium, and the 600 dpi × 600 dpi binary data A or B output from the quantization process 86-1 or 86-2 corresponding to these bands. It is a schematic diagram shown. Here, a band, which is a unit of an image area on a recording medium, indicates an image area in which recording is completed by the same recording scan of the recording head. Referring to FIG. 8, image data corresponding to band 1 is subjected to quantization processing 86-1 after image data distribution, and is output as binary data A <b> 1 of 600 dpi × 600 dpi. The other is subjected to quantization processing 86-2 and output as binary data B1 of 600 dpi × 600 dpi. Thereafter, the binary data A1 is subjected to dot arrangement pattern development processing 87-1 and converted to binary data A′1 of 600 dpi × 1200 dpi. The binary data B1 is subjected to dot arrangement pattern development processing 87-2 and converted to binary data B′1 of 600 dpi × 1200 dpi. Then, the binary data A′1 and the binary data B′1 are overlapped and recorded by different main scans to complete the band 1 image. The same applies to bands 2 and below. That is, band n is distributed to binary data An and binary data Bn, converted to A′n and B′n by dot arrangement pattern development processing 88-1 or 88-2, and overlapped by different main scans. Thus, the image of band n is completed.

  FIGS. 13A to 13C are diagrams for explaining the difference in recording method between the case where the dot pattern recording order is unified and the case where the dot pattern recording order is not unified for all areas of the recording medium. In the figure, the relative positional relationship between the individual bands and the recording head in the transport direction (y direction) is shown. In the case of two-pass multi-pass printing, the 512 nozzles arranged in the print head can be divided into an upstream area and a downstream area, each of which is 256 with respect to the recording medium conveyance direction. In any band, recording is performed by the upstream region of the recording head in the first recording scan, and after the recording operation of the recording medium for 256 nozzles, the downstream side of the recording head is performed in the second recording scan. Recording is performed by area.

  Here, FIG. 13A shows a recording method in which the types of dot patterns are unified in the upstream area and the downstream area of the recording head. In the figure, in the first scan, binary data A1 for band 1 is recorded with a dot pattern a in the upstream region of the recording head. In the second scan performed after the transport operation for 256 nozzles, binary data B1 for band 1 is recorded with a dot pattern b in the downstream area of the recording head, and at the same time, binary data B2 for band 2 is recorded in the upstream area. Is recorded with the dot pattern b. Further, in the third scan performed after the transport operation for 256 nozzles, binary data A2 for band 2 is recorded with a dot pattern a in the downstream area of the recording head, and at the same time, binary data for band 3 is recorded in the upstream area. A3 is recorded with the dot pattern a. When such a recording operation is repeated, the recording head performs recording according to the same dot pattern in the upstream region and the downstream region in any recording scan. That is, the recording head may record binary data An and An + 1 with dot pattern a or Bn and Bn + 1 with dot pattern b for each recording scan.

  However, when such recording is performed, a situation occurs in which the order of the dot patterns recorded on the recording medium differs from band to band. For example, in band 1, the binary data B1 is recorded with the dot pattern b in the next recording scan in which the binary data A1 is recorded with the dot pattern a. Also for the odd bands such as band 3 and band 5, the binary data Bn is recorded by the dot pattern b after the binary data An is recorded by the dot pattern a. On the other hand, in the even bands such as band 2 and band 4, the binary data An is recorded by the dot pattern a in the recording scan after the binary data Bn is recorded by the dot pattern b. In other words, the dot pattern b is recorded after the dot pattern a is recorded in the odd band, but the order is reversed in the even band.

  In general, in inkjet recording, a pattern in which dots are relatively dispersed, such as a dot pattern a, and a pattern in which dots are relatively aggregated, such as a dot pattern b, are covered with dots on a blank area. The area is different. Specifically, when the dots are relatively dispersedly recorded as in the dot pattern a, the blank area where the coverage is largely left is smaller. Further, such a covering area is also affected by a recording position shift between the two nozzle rows 1301 and 1302 (see FIG. 6B) that discharge the same ink. In other words, the coverage of each scan varies depending on the dispersion state of the dot pattern to be used and the recording position shift between the two nozzle rows. In addition, in the case of multi-pass printing, the diameter of the dots recorded on the surface where the dots have already been recorded and the ink has penetrated is larger than the diameter of the dots recorded first on the blank area of the recording medium. Tend. Therefore, considering these phenomena in combination, the density differs between the area where the dot pattern b is recorded after the dot pattern a is recorded and the area where the dot pattern a is recorded after the dot pattern b is recorded. There is a case. That is, in the recording method as shown in FIG. 13A, the density differs between the odd-numbered band and the even-numbered band, and there is a concern that this is recognized as density unevenness.

  On the other hand, 13 (b) shows a recording method that unifies the dot pattern recording order in all bands of the recording medium. In the figure, in the first scan, binary data A1 for band 1 is recorded with a dot pattern a in the upstream region of the recording head. In the second scan performed after the transport operation for 256 nozzles, binary data B1 for band 1 is recorded with a dot pattern b in the downstream area of the recording head, and binary data A2 for band 2 is simultaneously recorded in the upstream area. Is recorded with a dot pattern a. Further, in the third scan performed after the transport operation for 256 nozzles, binary data B2 for band 2 is recorded with a dot pattern b in the downstream area of the recording head, and at the same time, binary data for band 3 is recorded in the upstream area. A3 is recorded with the dot pattern a. When such a recording operation is repeated, the recording head performs recording according to different dot patterns in the upstream area and the downstream area in any recording scan. However, in the recording medium, the dot pattern recording order is unified so that the dot pattern a is recorded in all bands and then the dot pattern b is recorded. That is, the recording method as shown in FIG. 13B is more preferable than the recording method shown in FIG. 13A because the density is unified between the odd-numbered band and the even-numbered band and it is difficult to cause density unevenness. Then, the recording method shown in FIG.

  Therefore, referring to FIG. 8 again, in this embodiment, the binary data A′n converted into 1200 dpi × 600 dpi according to the dot pattern a in the dot arrangement pattern development processing unit 87-1 is the upstream for the next scan. The data is stored in the side area buffer 88-1. Recording is performed in the next scan by the upstream area of the recording head. Also, the binary data B′n converted into 1200 dpi × 600 dpi according to the dot pattern b in the dot arrangement pattern development processing unit 87-2 is stored in the downstream area buffer 88-2 for the current scan, and is stored in the recording head. Recording is performed in this scan by the downstream area. In the recording head, when binary data to be recorded is stored in both the upstream area buffer and the downstream area buffer, one (this time) recording scan is executed. By performing such memory management, the first scan dot pattern is always recorded in the first scan, which is the first print scan, and the second scan dot pattern is recorded in the second scan. Can be unified in any area of the recording medium.

  FIG. 13C shows another recording method that can be employed in the present embodiment in order to unify the dot pattern recording order in all bands of the recording medium. In the figure, in the first scan, binary data A1 for band 1 is recorded with a dot pattern a in the upstream region of the recording head. In the second scan performed after the transport operation for 256 nozzles, binary data B1 for band 1 is recorded with a dot pattern b in the downstream area of the recording head, and at the same time, binary data B2 for band 2 is recorded in the upstream area. Is recorded with a dot pattern a. Further, in the third scan performed after the conveying operation for 128 nozzles, binary data A2 for band 2 is recorded with a dot pattern b in the downstream area of the recording head, and at the same time, binary data for band 3 is recorded in the upstream area. A3 is recorded with the dot pattern a. Even when such a recording operation is repeated, in the recording medium, the dot pattern a is recorded in all bands and then the dot pattern b is recorded, and the density is unified in the odd and even bands. It is difficult to invite uneven density.

  When this recording method is adopted, referring to FIG. 8, the binary data A output from the quantization process 86-1 and the binary data B output from the quantization process 86-2 In the arrangement patterning process, it is necessary to use different dot patterns for each band. For this purpose, for example, the binary data A output from the quantization process 86-1 and the binary data B output from the quantization process 86-2 are used as the dot arrangement pattern development process 87-1 and the dot arrangement pattern development. What is necessary is just to make it the structure which is input into process 87-2 alternately. Alternatively, the dot patterns used in the dot arrangement pattern development process 87-1 and the dot arrangement pattern development process 87-2 may be alternately switched between the dot pattern a and the dot pattern b.

  FIGS. 14A and 14B show another example of the first scanning dot pattern and the second scanning dot pattern for level 1 that can be employed in the present embodiment, as shown in FIGS. ) In the same manner as FIG. FIGS. 14A and 14B are dot patterns composed of 8 pixels × 2 pixels created by combining the same patterns (c) and (d) so that they are mutually exclusive. . Even when the dot pattern of this example is used, it is possible to output an image that does not invite density unevenness due to a recording position shift, as in the dot patterns shown in FIGS. 10A and 10B. . If the dot pattern is such that the covering area with respect to the recording medium is kept substantially constant regardless of the recording position shift, these dot patterns are assigned to the first recording scan and the second recording scan to each band. The recording order may be kept constant. By doing so, it is possible to output an image in which density unevenness due to a recording position shift is reduced.

(Second Embodiment)
FIG. 16 is a block diagram for explaining image processing when performing 2-pass multi-pass printing in the second embodiment. Since the processes from the multi-value image data input unit 1401 to the gradation correction process 1404 are the same as those in the first embodiment, description thereof will be omitted.

  The image data distribution unit 1405 of the present embodiment converts the multi-value data (C′M′Y′K ′), the first multi-value data for scanning (C1, M1, Y1, K1), and the multi-value data for second scan. (C2, M2, Y2, K2) and the first and second scan common multi-value data (C3, M3, Y3, K3) are divided into three. The distribution at this time may be equally divided into three, but is not necessarily equal. However, for example, in the case of cyan, the multi-value data C ′ before distribution is converted into multi-value data C1 for the first scan, multi-value data C2 for the second scan, and multi-value common to the first and second scans. When distributing to the data C3, it is preferable that C1 + C2 + 2C3 = C ′ is satisfied. This is to save the image density output for the input value. However, for example, when the output image is desired to have a higher density, C1 + C2 + 2C3> C ′ may be set.

  First-scan multi-value data (C1, M1, Y1, K1) distributed by the image data distributor 1405, second-scan multi-value data (C2, M2, Y2, K2), and first and second scans The common multi-value data (C3, M3, Y3, K3) is input to the quantization processing unit 1406, respectively. In the quantization processing unit 1406 of the present embodiment, the binary data for the first scan, the binary data for the second scan, and the binary data common to the first and second scans are mutually exclusive. Quantization processing by the error diffusion method is performed while associating. To be exclusive means to perform processing so that C1, C2, and C3 do not become 1 (record) in the same pixel. Through such quantization processing, the quantization processing unit 1406 receives binary data for first scanning (quantized data), binary data for second scanning (quantized data), and Binary data (quantized data) common to the first and second scans is output.

  Thereafter, the binary data for the first scan and the binary data common to the first and second scans are input to the first scan quantized data synthesis unit 1407-1 and added (logical sum). The binary data for the second scan and the binary data common to the first and second scans are input to the second scan quantized data synthesis unit 1407-2 and added (logical sum). The two binary data obtained in this way are the same binary data common to the first and second scans, and the pixels set to 1 (record) have the same value (record), but other pixels are exclusive. It becomes a relationship.

  Thereafter, the binary data A output from the first scan quantized data composition unit 1407-1 is input to the dot arrangement pattern development process 1408-1, and by referring to the dot pattern a, binary of 600 dpi × 1200 dpi. Converted to data A ′. The binary data B output from the second scanning quantized data composition unit 1407-2 is input to the dot arrangement pattern development processing 1408-2, and by referring to the dot pattern b, binary of 600 dpi × 1200 dpi. Converted to data B ′. As the dot pattern to be referred to at this time, the patterns shown in FIGS. 10A and 10B and FIGS. 14A and 14B can be used.

  The 600 dpi × 1200 dpi binary data output from the dot arrangement pattern development processes 1408-1 and 1408-2 are stored in different areas of the print buffer, and are recorded in different scans. Specifically, the binary data A ′ output from the dot arrangement pattern development processing unit 1408-1 is stored in the upstream area buffer 1409-1 of the print head for the next scan. The recording is performed in the next scan instead of the current scan by the upstream region of the recording head. The binary data output from the dot arrangement pattern development processing unit 1408-2 is stored in the downstream area buffer 1409-2 for the current scan, and is recorded in the current scan by the area on the downstream side of the recording head. The In the recording head, when binary data to be recorded is stored in both the upstream area buffer and the downstream area buffer, one (this time) recording scan is executed. By performing such memory management, the dot pattern a is always recorded in the first scan that is the first recording scan, and the dot pattern b is recorded in the second scan in any region of the recording medium. Can be unified.

  According to the present embodiment, the ratio at which the multi-value data is distributed to the first and second scan common multi-value data in the image data distribution unit 1405 is the ratio of pixels that record overlapping dots in units of 600 dpi × 600 dpi. That is, the ratio of overlapping dots can be controlled to some extent by adjusting the ratio of distribution to the first and second scanning common multi-value data in the image data distribution unit 1405.

  In general, the density fluctuation accompanying the recording position deviation is affected by the number and ratio of overlapping dots prepared in advance. For example, when no overlapping dots are prepared in advance, the image density decreases as described with reference to FIGS. However, for example, as shown in FIG. 15A, when a recording position shift occurs in a state where all the dots are overlapping dots, the coverage area increases and the image density increases as shown in FIG. 15B. As described above, the density variation due to the recording position shift is affected by the number and ratio of overlapping dots prepared in advance. According to the present embodiment, it is possible to adjust the number of overlapping dots in accordance with the degree of density unevenness caused by the recording position deviation. In addition to the first embodiment, the recording position deviation is more positive. It is possible to suppress the density unevenness associated with.

  In the above-described two embodiments, the description has been given taking the case of two-pass multi-pass recording as an example. However, the above-described embodiments can of course be applied to multi-pass recording of three or more passes. In general, in M-pass printing in which an image of the same area is printed M times (M ≧ 2), if different dot patterns are prepared for each of M quantized data after quantization processing, the above-described implementation is performed. The effect of form can be demonstrated. In the case of the second embodiment, the multi-value data is divided into N values that are larger than the multipath number M, and the N multi-value data are quantized respectively and added together to obtain M quantum data. To obtain data.

(Third embodiment)
FIG. 17 is a block diagram for explaining image processing when performing two-pass multi-pass printing in the third embodiment. Since the processes from the multi-value image data input unit 201 to the gradation correction process 204 are the same as those in the above embodiment, the description thereof is omitted.

  In the present embodiment, the 256-valued multi-value data (C′M′Y′K ′) that has been subjected to the gradation correction processing is input to the quantization processing 205 without being distributed, and level 0 to level 2 is input. It is quantized into ternary data (C ″ M ″ Y ″ K ″) having values. As a quantization method at this time, general multi-level error diffusion processing can be used. Thereafter, the quantized ternary data (C ″ M ″ Y ″ K ″) is input to the pass separation + dot arrangement pattern processing 206.

  In the pass separation + dot arrangement pattern processing 206, by referring to the table a prepared in advance and the table b different from this, the position where each pixel dot of 1200 dpi × 600 dpi is recorded in each scan from the input ternary data is determined. decide.

  18A and 18B are diagrams showing a table a (FIG. 18A) and a table b (FIG. 18B) that can be used in the present embodiment. In the figure, each grid indicates one pixel area of 600 dpi × 600 dpi, and each table has an area corresponding to 4 pixels × 4 pixels for a pixel of 600 dpi × 600 dpi. Each table is composed of 2-bit parameters for each pixel, with the upper bits indicating the mask data of the pixel and the lower bits indicating the dot pattern of the pixel. Such a table is stored in advance in the memory 3003 in the apparatus.

  FIGS. 19A and 19B are diagrams respectively showing the contents of the mask data indicated by the upper bits used in the present embodiment and the contents of the arrangement pattern indicated by the lower bits. Referring to FIG. 19A, the mask of this embodiment is prepared in two masks: a mask 0 that is set when the upper bit is 0, and a mask 1 that is set when the upper bit is 1. ing. Each mask independently determines whether dot recording is allowed (1) or not allowed (0) in units of 600 dpi × 600 dpi depending on the value of the ternary data included in the pixel. For example, if the value of the ternary data is level 1, the mask 0 does not allow dot recording (0), but the mask 1 allows (1). When the value of the ternary data is level 0, neither dot recording of the mask 0 nor the mask 1 is allowed (0). When the value of the ternary data is level 2, the dot recording is allowed for both the mask 0 or the mask 1. (1).

  On the other hand, FIG. 19B is a dot pattern showing a recording position when dots are recorded. The pattern 0 set when the low-order bit of the table parameter is 0 indicates that a dot is recorded in the upper pixel among two pixels of 600 dpi × 1200 dpi arranged in parallel in 2 pixels in the y direction × 1 pixel in the x direction. . On the other hand, pattern 1 set when the low-order bit of the table parameter is 1 indicates that dots are recorded in the lower pixel of the two pixels.

  FIGS. 20A to 20C are views showing the state of data conversion in the pass separation + dot arrangement pattern processing 206 when the table a and the table b are used. FIG. 20A shows an example of ternary data output from the quantization processing 205, and FIGS. 20B and 20C show the ternary data and dot patterns obtained from the table a and the table b, respectively. . In the ternary data output from the quantization process 205, when the level 0 to level 2 are equally arranged to some extent as shown in FIG. 20A, both the first scan dot pattern and the second scan dot pattern The dots are dispersed moderately. As a result, there are pixels in which dots are recorded overlappingly in both the first scan and the second scan in some places, and even when a recording position shift occurs as in the above-described embodiment, the coating on the recording medium is performed. The rate can be maintained within a certain range.

  FIGS. 21A to 21C are diagrams showing another example of data conversion in the pass separation + dot arrangement pattern processing 206 when the table a and the table b are used. FIG. 21A is an example of the ternary data output from the quantization processing 205, and here, all the pixels have a level 2 value. In the case of such an input value, the dot patterns of the first and second scans are as shown in FIGS. As described above, when all of the ternary data output from the quantization processing 205 are level 2 (maximum density value), dots are recorded in all pixels in both the first scanning dot pattern and the second scanning dot pattern. The However, since the 1200 dpi × 600 dpi pixel position where dots are actually recorded is determined independently in the first scan and the second scan, the dots are recorded in duplicate in both the first scan and the second scan. And pixels on which dots are recorded in one of the first scan and the second scan are mixed. As a result, as in the above-described embodiment, even when a recording position shift occurs, the coverage with respect to the recording medium can be maintained within a certain range.

  Referring to FIG. 17 again, the 600 dpi × 1200 dpi binary data A ′ and B ′ output from the pass separation + dot arrangement pattern 206 are stored in different areas of the print buffer and recorded by different scans. Specifically, the binary data A ′ processed using the table a is stored in the upstream area buffer 207-1 of the print head for the next scan. The recording is performed in the next scan instead of the current scan by the upstream region of the recording head. The binary data B ′ processed using the table b is stored in the downstream area buffer 207-2 for the current scan, and is recorded in the current scan by the area on the downstream side of the recording head. The following recording method is the same as that in the above embodiment.

  As described above, according to the present embodiment, a table for defining a mask and a dot pattern is prepared with different contents by the number of scans of multi-pass printing, and the printing order of the tables is individually set while addressing these to each printing scan. Record to keep constant in the band. As a result, similarly to the above-described embodiment, it is possible to output an image in which uneven density due to a recording position shift is reduced.

  In the above-described third embodiment, the description has been given taking the case of 2-pass multi-pass printing as an example. However, the above-described embodiment can of course be applied to multi-pass printing of three or more passes. In the case of M-pass printing in which an image of the same area is printed M times (M ≧ 3), M tables having different parameter contents are prepared in advance, and each of such M tables is quantized. It is only necessary to generate M binary data corresponding to the quantized data after processing.

  Further, in the above embodiment, the dot pattern that is resistant to the recording position deviation in the transport direction (y direction) has been described, but the present invention can naturally cope with the recording position deviation in the main scanning direction. At this time, in the above-described embodiment, the recording resolution is set to 1200 dpi only in the y direction. However, in order to further improve the resistance to the recording position shift in the main scanning direction, the recording resolution in the x direction is also set to 1200 dpi. Is effective.

  However, the resolution value and the dot size to be recorded are not limited to the above values. The effect of the present invention can be exhibited if the coverage with respect to the recording medium does not change so much between when the recording position shift does not occur and when it occurs. Therefore, the resolution value and the size of the dots to be recorded are not particularly limited as long as both values are determined in association with each other. Of course, the size of the dot pattern is not limited to a 4 pixel × 4 pixel region as in the above embodiment.

  In the above embodiment, error diffusion is adopted as the quantization method, but the present invention is not limited to this. In the present invention, any dot pattern may be used in the final binarization corresponding to the recording resolution. For quantization processing before that, various methods such as dithering are used in addition to error diffusion. I can do it.

  Further, in the above-described embodiment, a buffer for next scanning and a buffer for current scanning are prepared, and scanning of the recording head is performed once at a timing when binary data is filled in the entire area of the buffer for current scanning. Although described in the configuration, the present invention is not limited to such a configuration. Each of the binary data divided into a plurality of bands may be recorded in order by different scanning for each band. For example, after all the binary data for one page is generated, one page by the recording head is generated. The recording operation may be performed.

  The present invention is also realized by a program code constituting a computer readable program for realizing the above-described image processing function or a storage medium storing the program code. In this case, the image processing described above is realized by the computer (or CPU or MPU) of the host device or image forming apparatus reading and executing the program code. Thus, the present invention includes a computer-readable program for causing a computer to execute the above-described image processing, or a storage medium storing the program.

85 Image data distribution unit 86-1 86-2 Quantization unit 87-1 87-2 Dot arrangement pattern development unit 88-1 Next scan upstream region buffer 88-2 Current scan downstream region buffer

Claims (16)

There rows relative scanning of the run査direction between the recording head for ejecting the recording medium and the ink, at least a first to a given area on the recording medium, each of the multiple scans comprising a second scan In the predetermined area, binary recording data corresponding to a first resolution for recording an image in the predetermined area by ejecting ink to each of the plurality of pixel areas in the predetermined area to record dots is recorded. An image processing apparatus that generates an image based on multi-value image data corresponding to a region and corresponding to a second resolution lower than the first resolution,
By distributing the image data, at least the first scan corresponding to the first scan and the second resolution corresponding to the second resolution, at least the second scan, and the Distribution means for generating a plurality of multi-value data including second multi-value data corresponding to the second resolution;
By quantizing each of the first and second multi-value data generated by the distribution means , each of the first and second M values (M ≧ 2) corresponds to the second resolution. A quantization means for generating the quantized data of
Acquisition means for acquiring a plurality of dot patterns that correspond to the first resolution and determine the number and positions of dots to be recorded in a plurality of pixel areas in the predetermined area according to the values of the quantized data , respectively ; ,
A first for performing recording in the first scan based on the first quantized data generated by the quantizing unit and any of the plurality of dot patterns acquired by the acquiring unit ; Generate the recording data, and record in the second scanning based on the second quantized data generated by the quantizing unit and any of the plurality of dot patterns acquired by the acquiring unit Recording data generating means for generating the second recording data for performing
The recording data generation unit is configured to output the first dot of the plurality of dot patterns when the values of the first and second quantization data generated by the quantization unit are the same predetermined value. The first recording data is generated based on a pattern, the second recording data is generated based on the second dot pattern of the plurality of dot patterns, and the dot data in the second dot pattern is generated . Among the plurality of pixel areas that determine recording, at least one first pixel area is a pixel area that determines non-recording of dots in the first dot pattern, and is different from the first pixel area. 2. The image processing apparatus according to claim 2, wherein the second pixel area is a pixel area that determines dot recording in the first dot pattern.   The image processing apparatus according to claim 1, wherein the quantization unit quantizes each of the first and second multi-value data by an error diffusion method.   The image processing apparatus according to claim 1, wherein the quantization unit binarizes each of the first and second multi-value data. When the first and second multi-valued data are substantially equal to each other, the quantization means is configured so that the first and second quantized data have the predetermined values, respectively. 4. The image processing apparatus according to claim 1 , wherein each of the second multi-value data is quantized . 5. The first dot pattern and the second dot pattern have a dot coverage area in an image recorded when a recording position shift occurs between the first scan and the second scan. When the recording position shift between one scan and the second scan does not occur, the dot recording or non-printing for each of the plurality of pixel regions is performed so as to be approximately equal to the dot covering area in the recorded image. The image processing apparatus according to claim 1, wherein recording is defined.   A first scanning area including the predetermined area and performing recording by the plurality of scans; and a first scanning area adjacent to the first scanning area and including the other predetermined area and performing recording by the plurality of scannings. The recording apparatus according to any one of claims 1 to 5, wherein when performing printing in each of the two scanning areas, the second scanning is a scanning after the first scanning. The image processing apparatus described.   7. The scan according to claim 6, wherein the second scan is a scan after the first scan, regardless of which scan region is printed on the print medium. Image processing device. The recording head has at least a first ejection port array in which a plurality of ejection ports that eject ink are arranged in an arrangement direction intersecting the scanning direction,
The recording medium is conveyed from the upstream side to the downstream side along a conveyance direction intersecting the scanning direction between the first scanning and the second scanning,
The first print data includes pixels in the predetermined area from a first discharge port group composed of a plurality of the discharge ports continuously arranged in the first discharge port array in the first scan. And the second recording data is continuously arranged in the first ejection port array in the second scan, and the second recording data is more than the first ejection port group. 8. The method according to claim 6, wherein the ink is used when ink is ejected from the second ejection port group including the plurality of ejection ports arranged on the downstream side to each pixel in the predetermined region. Image processing apparatus. In the recording head, a plurality of ejection ports for ejecting ink are arranged in the arrangement direction, and each of the plurality of ejection ports is arranged in the first ejection port array and adjacent to the arrangement direction. Further having a second discharge port array arranged so as to be positioned in the arrangement direction of
The first print data includes pixels in the predetermined region from a third discharge port group composed of a plurality of the discharge ports continuously arranged in the second discharge port row in the first scan. The second recording data is continuously arranged in the second ejection port array in the second scan, and is used more than the third ejection port group. The image according to claim 8, wherein the image is used when ink is ejected from a fourth ejection port group including a plurality of ejection ports arranged on the downstream side to each pixel in the predetermined region. Processing equipment.   The recording data generation unit discharges ink from the first ejection port group in the predetermined scan when generating recording data for ejecting ink from the second ejection port group in the predetermined scanning. The image processing apparatus according to claim 8, wherein a dot pattern different from the dot pattern used when generating print data for printing is used. The distribution unit further generates third multi-value data corresponding to both the first and second scans, and corresponding to the second resolution, the multi-value image data;
The quantization means further generates third quantized data corresponding to the second resolution by quantizing the third multi-value data generated by the distributing means ,
Wherein said first generated by the quantization means, the third generating the fourth quantized data corresponding to the first scan on the basis of the quantized data, the second generated by the quantization means , Further comprising synthesis means for generating fifth quantized data corresponding to the second scan based on the third quantized data,
The recording data generating unit generates the first recording data based on the fourth quantized data generated by the synthesizing unit and any of the plurality of dot patterns acquired by the acquiring unit. And generating the second recording data based on the fifth quantized data generated by the synthesizing unit and any of the plurality of dot patterns acquired by the acquiring unit. The image processing apparatus according to any one of claims 1 to 10. The image processing apparatus according to claim 1, wherein the first and second dot patterns are defined to record the same number of dots.   The image processing apparatus according to claim 1, wherein the first resolution is 600 dpi × 1200 dpi, and the second resolution is 600 dpi × 600 dpi.   The image processing apparatus according to claim 1, wherein the predetermined area includes 32 pixel areas.   15. A program that causes a computer to function as the image processing apparatus according to claim 1. There rows relative scanning of the run査direction between the recording head for ejecting the recording medium and the ink, at least a first to a given area on the recording medium, each of the multiple scans comprising a second scan In the predetermined area, binary recording data corresponding to a first resolution for recording an image in the predetermined area by ejecting ink to each of the plurality of pixel areas in the predetermined area to record dots is recorded. An image processing method for generating based on multivalued image data corresponding to a region and corresponding to a second resolution lower than the first resolution,
By distributing the image data, at least the first scan corresponding to the first scan and the second resolution corresponding to the second resolution, at least the second scan, and the A plurality of multi-value data including second multi-value data corresponding to the second resolution;
By quantizing each of the first and second multi-value data, first and second quantized data corresponding to the second resolution and having M values (M ≧ 2) are generated. ,
A plurality of dot patterns that correspond to the first resolution and determine the number and positions of dots to be recorded in a plurality of pixel areas in the predetermined area according to the values of the quantized data , respectively , Generating the first recording data for recording in the first scan based on the quantized data and any of the plurality of dot patterns , and generating the second quantized data and the plurality of dots Generating the second recording data for recording in the second scanning based on any one of the patterns;
When the values of the first and second quantized data are the same predetermined value, the first recording data is generated based on the first dot pattern of the plurality of dot patterns, The second print data is generated based on the second dot pattern of the plurality of dot patterns , and at least one of the plurality of pixel regions defining the dot recording in the second dot pattern. One pixel area is a pixel area that determines non-recording of dots in the first dot pattern, and at least one second pixel area different from the first pixel area is dot recording in the first dot pattern. An image processing method characterized by being a pixel region that defines