JP2005161630A - Inkjet recording system and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep the number of ejections of each nozzle at a predetermined value or above, while data for pre-ejection onto a paper surface are generated by a simple constitution, in an inkjet recording system and an inkjet recording method, wherein the data for the pre-ejection onto the paper surface are added in the multivalued stage of the recording data, so that binarization processing can be performed by index development. <P>SOLUTION: In this inkjet recording system, it is determined according to a prescribed method whether or not the pre-ejection onto the paper surface is performed for one pixel; one signal value is added to the recording data by being newly selected from among a plurality of kinds of signal values, in terms of the pixel to which the pre-ejection onto the paper surface is applied; and in the index development after that, the matrix patterns equal in the number of recorded dots and different in arrangement are made to correspond to the plurality of kinds of added signal values. Thus, since ejection data on the pre-ejection onto the paper surface depending on the resolution of the nozzle can be created while additional processing of the pre-ejection onto the paper surface is performed in a resolution equivalent to quantization, the number of the ejections of the nozzles can be kept at a predetermined number or above in each recording scanning. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording system and an ink jet recording method for performing recording on a recording medium by ejecting ink from a recording head, and more particularly to preliminary ejection performed to stabilize the ejection state of the recording head.

  2. Description of the Related Art Inkjet recording apparatuses are widely used as recording apparatuses in printers, copiers, facsimiles, and the like, or apparatuses that output information processed by a composite electronic apparatus including a computer or a word processor or a workstation. In an ink jet recording apparatus, recording can be performed in a non-contact state with respect to a recording medium with a relatively simple configuration, and recording can be attempted regardless of the type of recording medium. Therefore, in recent years, in addition to paper, cloth, plastic sheets, and OHP sheets, those capable of recording on various recording media such as leather, nonwoven fabric, and metal have been proposed and provided.

  Among ink jet recording apparatuses, in particular, a so-called bubble jet (registered trademark) system, in which bubbles are generated in ink by using thermal energy generated by an electrothermal conversion element, and ink is discharged by the pressure of the bubbles, discharge ports and In recent years, nozzles for guiding ink can be arranged at a relatively high density, and since it has a number of advantages such as a low noise generated with a recording operation, it has been widely used in recent years.

  Even in such a bubble jet (registered trademark) system or other systems, the ink jet recording apparatus directly ejects ink from the ejection head and nozzle of the recording head, so generally maintenance processing specific to the ink jet recording head is required. It becomes. Then, by performing the maintenance process, the recording head can be maintained in a state where stable ejection can be performed. Hereinafter, several means for performing the maintenance process of the recording head will be described.

1. Suction unit A unit made of a material such as rubber is brought into contact with the surface of the discharge port, and ink near the discharge port is sucked from the nozzle through the cap. This removes bubbles that have been mixed in or generated due to continuous ink discharge or non-use of the device for a long period of time, and these bubbles cause the ink supply to the liquid path and the discharge operation to be hindered. Defects can be prevented beforehand.

2. Wiper means A means for wiping and removing ink adhering to the periphery of the ejection port by bringing a blade made of an elastic material such as rubber into contact with the ejection port surface and moving the recording head in this state. Ink mist generated when ink is ejected from the recording head and splash generated by impact when the ejected ink hits the recording medium adheres to and closes the ejection opening, causing ejection failure. There is. The wiper means can wipe out and remove such ink to prevent ejection failure.

3. Preliminary ejection means In general, the ink ejection is irrelevant to recording at a place other than the recording medium other than during actual recording. When an image is recorded, ink is ejected from a nozzle at a location corresponding to the recording data at a timing corresponding to the recording data. In this case, there are variations in the number of ejections between a plurality of nozzles, and some nozzles do not eject ink for a long time. In such a nozzle, since the ink in the nozzle remains exposed to the outside air, the volatile components in the ink evaporate, the colorant concentration of the ink increases, and the viscosity increases. In this case, in the next recording, there is a concern that an ejection failure may occur when the amount or speed of ink ejected from the nozzle is reduced or the ejection direction is deflected. Applying preliminary ejection means can increase the number of ejections of nozzles that were not used frequently during recording, remove ink with increased viscosity, and reduce ejection variation between multiple nozzles. This makes it possible to maintain a stable discharge state in the nozzles.

  By the way, in recent years, many ink jet recording apparatuses that apply light cyan or light magenta having a lower density in addition to cyan, magenta, yellow, and black necessary for full color recording are provided. By adopting such a configuration, it is possible to output a high-quality image having more excellent gradation while reducing the granularity of ink dots at a low density. In addition, as another method for reducing graininess, a technique for reducing the amount of ink ejected from the recording head is also in progress, and at the same time, a technique for arranging a large number of ejection openings on the recording head at high density. By using together, it has become possible to record a higher resolution image at a higher speed.

  As described above, in the recent technical background in which the number of nozzles provided in the recording apparatus increases and the volume of ejected ink droplets decreases, the above-described recording head maintenance process is also more suitable. It is hoped that it will be improved.

  In particular, the reduction in the ejection volume per dot increases the ratio of the cross-sectional area of the nozzle to the ejection volume, that is, the surface area of the ink exposed to the outside air, so that more ink is evaporated per unit time. Connected. Therefore, in the preliminary ejection unit described in 3, in the configuration in which preliminary ejection is performed only at times other than actual recording (for example, at the end of each recording scan) as in the past, the interval between the preliminary ejection and the preliminary ejection is too long, In some cases, it is insufficient to prevent the occurrence of thickened ink. For example, for ejection ports and recording heads that are rarely used in a single recording scan of the recording head, the ink colorant density rises above an allowable range due to ink evaporation during the recording scan, and the same. Even within the scan, the density of the dots when discharged next becomes higher than usual. This phenomenon becomes more prominent in a recording apparatus that can record on a recording medium having a particularly large size and has a long recording scan distance. As a result, the density of the image varies depending on both ends or each location in the page, resulting in a recording with impaired uniformity.

  In order to solve this problem, several techniques have already been disclosed for performing preliminary ejection for a nozzle with a small number of ejections on a recording medium that is being recorded so as not to stand out on the image (for example, Patent Document 1 and (Refer to Patent Document 2.) According to the above technique, the frequency of preliminary ejection can be further increased as compared with the prior art, and thus the above-described generation of thickened ink and non-uniform density due to ink evaporation are suppressed. I can do it. Hereinafter, such preliminary ejection onto the recording medium will be referred to as “paper preliminary ejection” in this specification.

JP-A-55-139269 JP-A-6-40042

  In the case of performing preliminary ejection on the paper, recording is performed after adding preliminary ejection data on the paper to the original recording data obtained from the image data. When such data addition processing is performed, the processing method differs depending on whether the original data is binary or multi-valued. When the original data is binary, that is, when recording / non-recording at each location on the recording medium has already been determined, the preliminary ejection data on the paper is also created in binary and is directly logical with the original data. The sum can be taken and the result can be used as it is as recording data (ejection signal). At this time, since it is possible to consider a one-to-one relationship between the nozzle (discharge port) for which preliminary discharge is to be performed and the location where the preliminary discharge data on the paper is generated, the number of discharges at each nozzle is more than a predetermined value and evenly. The purpose of dispersion can be realized relatively easily. In the two patent documents disclosed in the section of the prior art, it can be determined that the original data is binary.

  However, in recent years, although the recording resolution of the recording apparatus is high resolution, the pixel data input to the recording apparatus has a lower resolution, and one pixel has gradation values of several stages (three or more values). Data forms are becoming common. In this case, the area on the recording medium occupied by one pixel input with low resolution is divided into N × M areas corresponding to the resolution of the recording apparatus, and recording / non-recording of dots in this area is performed. In many cases, a method of expressing a gradation value of a pixel, that is, an index method is employed. In the index method, a matrix pattern in which recording / non-recording of dots in each M × N area is determined in accordance with each gradation value, and final binarization processing is executed by this operation. .

  FIG. 1 is a diagram schematically showing an example of a matrix pattern in the index method. Here, 600 × pi (pixels / inch; reference value) image data having five gradation values from 0 to 4 is used, and a matrix pattern of 2 areas × 2 areas is used to make 1200 × 1200 dpi (dots / inch; An example of generating binary recording data of (reference value) is shown. 0000 to 0100 arranged on the left side of the drawing indicate 4-bit recording data included in each pixel. Reference numerals 700 to 719 shown on the right side indicate matrix patterns developed corresponding to each recording data. In each matrix pattern, dot recording / non-recording is determined in each 2 × 2 area included therein. It has been. Here, the vertical direction corresponds to the nozzle arrangement direction arranged in the recording head, and two areas adjacent in the vertical direction indicate areas recorded by adjacent nozzles. Also, the black area indicates the area where dots are recorded, and the white area indicates the area where dots are not recorded.

  As one of indexing methods using such a matrix pattern, one development pattern (for example, 700, 704, 708, 712 and 716) is assigned to each recording data “0000” to “0100”, There is also a method in which one pattern is fixedly associated with one density value. In this way, since the density and density of the dot arrangement after recording are less likely to occur and the dot dispersibility is good, it is possible to form a smooth image with a relatively low graininess. However, on the other hand, as shown by 704 and 712, the arrangement of recording dots is uneven between the upper and lower nozzles, so that the frequency of use of each nozzle varies, and density unevenness and streaks become conspicuous as recording continues. There are concerns that the recording head itself may be affected.

  Therefore, in recent inkjet recording apparatuses, for example, a method of developing while assigning different patterns as indicated by 704 to 707 to the index data 0001 corresponding to the gradation value 1 in a predetermined order is also applied. In FIG. 1, patterns 700, 701, 702, and 703 for index data “0000”, patterns 704, 705, 706, and 707 for “0001”, and pattern 708 for “0010”. , 709, 710, 711, patterns 712, 713, 714, 715 are assigned to “0011”, and patterns 716, 717, 718, 719 are assigned to “0100”. . For convenience, four same patterns are set for “0000” and “0100”, but may be simplified to one when actually used.

  By the way, when performing data expansion employing such an index method, two methods are conceivable when applying the above-described preliminary ejection on the paper. One is a method of adding preliminary ejection data using a method or the like according to the above-described prior art after performing index expansion processing and binarizing print data. However, in a recent recording apparatus configuration in which the recording resolution is high and the number of recording data is enormous, if the method of the above prior art is adopted as it is, the electric circuit configuration inside the recording apparatus becomes large. As a result, the cost increases, or the recording speed is lowered due to the operation of adding the preliminary ejection data, so that many concerns arise.

  Therefore, as another method, the preliminary paper ejection data to be added is created in a multi-valued state indicated by 0001 to 0110 in FIG. 1 and added to the original data in this state, similarly to the original recording data. Then, a method of performing a normal index expansion process is considered. In this way, it is possible to perform the work of adding the preliminary paper ejection data in a lower resolution state, so that the configuration is relatively simple without significantly affecting the configuration and recording time of the recording apparatus. Can achieve the purpose.

  However, unlike the case where the processing in the binary data state described above is performed, since the image resolution and the recording resolution at the stage of adding the preliminary ejection data are different, the preliminary ejection is performed with the pixel that generates the additional data. It is not possible to consider one-on-one with the desired nozzle. In particular, when a method of fixedly corresponding one pattern to one index value is employed, for example, when “0001” in FIG. 1 is added as preliminary ejection data, preliminary ejection is performed. As shown by reference numeral 704, the nozzle is fixed only to the upper nozzle, and no preliminary discharge is performed on the lower nozzle.

  On the other hand, when a plurality of matrix patterns are sequentially switched to correspond to one print data value indicating a gradation value, for example, as shown in 704 to 707, it is possible to expect some equalization of preliminary ejection. . However, since the matrix patterns (704 to 707) are arranged on the paper surface in a predetermined order with respect to one type of quantized recording data (0001), when it is desired to perform preliminary ejection of a desired nozzle, Limiting the position where the preliminary ejection data for the paper is generated, such as creating preliminary ejection data for the paper in consideration of the arrangement of the matrix pattern, makes control difficult.

  The present invention has been made in view of the above problems, and an object of the present invention is to add ink for pre-discharge on a paper surface when recording data is multi-valued, and then perform binarization processing by index expansion. In the recording system, while generating the preliminary ejection data on the paper surface with a relatively simple configuration, the number of ejections at each nozzle is reliably maintained at a predetermined level or more.

  Therefore, in the present invention, recording is performed by ejecting ink from a plurality of recording elements to the recording medium, and preliminary recording from the recording elements is performed on the recording medium in order to maintain good ink ejection performance of the recording elements. An ink jet recording system using an ink jet recording apparatus capable of performing a preliminary ejection process for ejecting ink to the image forming apparatus, and quantizing means for quantizing one pixel into recording data capable of expressing gradation values in several steps; Determining whether or not to perform preliminary ejection processing on the recording medium for the pixel, and newly selecting a predetermined signal value from a plurality of types of signal values for the pixel to be performed. Preliminary ejection data adding means to be added to the recording data obtained by the quantizing means, and recording data created by the preliminary ejection data adding means are assigned to the one pixel. Index development means for performing binarization processing by corresponding to a matrix pattern that defines dot recording / non-recording in each of a plurality of areas constituting the corresponding area, and binary values obtained by the index development means Recording means for ejecting ink from a plurality of recording elements according to the recording data, and the plurality of types of signal values added by the preliminary ejection data adding means have the same number of dots recorded by the index developing means. And the matrix patterns having different dot arrangements correspond to each other.

  In addition, an inkjet recording system using an inkjet recording apparatus capable of performing a preliminary ejection process in which ink is preliminarily ejected from the recording element to the recording medium in order to maintain good ejection performance. Quantizing means for quantizing multi-level recording data capable of expressing gradation values in several stages, and multi-value preliminary ejection data for the multi-value recording data quantized by the quantization means The preliminary ejection data adding means to be added and the multi-value recording data to which the multi-value preliminary ejection data has been added by the preliminary ejection data adding means are added to each of a plurality of areas constituting the area corresponding to the one pixel. Binarizing means for performing binarization processing by corresponding to a matrix pattern that defines recording / non-recording of the preliminary ejection data adding means. As a matrix pattern corresponding to the multi-valued preliminary discharge data to be added Ri, wherein the number of dots are used a plurality of matrix patterns and dot arrangement are different same.

  Further, recording is performed by ejecting ink from a plurality of recording elements to the recording medium, and ink is preliminarily ejected from the recording element to the recording medium in order to maintain good ink ejection performance of the recording element. An ink jet recording method using an ink jet recording apparatus capable of performing a preliminary ejection process, wherein a quantization step of quantizing one pixel into recording data capable of expressing gradation values of several stages, Whether or not to perform preliminary ejection processing on the recording medium is determined, and for the pixel to be performed, a predetermined signal value is newly selected from a plurality of types of signal values, and the quantization step The preliminary ejection data adding step to be added to the recording data obtained by the above, and the recording data created by the preliminary ejection data adding step constitute an area corresponding to the one pixel In accordance with a matrix pattern that defines dot recording / non-recording in each of a plurality of areas, an index development process for performing binarization processing, and a plurality of binary recording data obtained by the index development process The plurality of types of signal values added by the preliminary ejection data adding step have the same number of dot recordings and different arrangements depending on the index development step. The matrix patterns correspond to each other.

  An inkjet recording method using an inkjet recording apparatus capable of performing a preliminary ejection process in which ink is preliminarily ejected from the recording element to the recording medium in order to maintain good ejection performance. A quantization process for quantizing multi-level print data that can express gradation values in stages, and multi-value preliminary ejection data are added to the multi-value print data quantized in the quantization process Preliminary ejection data adding step and multi-value recording data to which multi-level preliminary ejection data is added in the preliminary ejection data adding step are recorded in each of a plurality of areas constituting the area corresponding to the one pixel. A binarization process for performing binarization processing by corresponding to a matrix pattern that defines non-recording, and is added in the preliminary ejection data adding process. That a matrix pattern corresponding to the multi-valued preliminary ejection data, wherein the number of dots are used a plurality of matrix patterns and dot arrangement are different same.

  According to the present invention, it is possible to add the preliminary ejection data on the paper that can correspond to the resolution of the nozzle while performing the processing at the same resolution as the quantization. Therefore, in each recording scan, it is possible to realize the preliminary ejection on the paper that can maintain the ejection number of the plurality of nozzles at a predetermined number or more.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a top view for explaining a schematic configuration of the ink jet recording apparatus applied to the present embodiment.

  In FIG. 2, 2 is a recording apparatus main body including a paper transport system unit, and 1 is a carriage. The carriage 1 is mounted with the recording head 5 and moves in the direction of the arrow in the figure, so that the recording head 5 can scan the recording medium. The carriage 1 is guided and supported so as to be movable along the guide shaft 11, and can reciprocate by a driving force transmitted via the belt 13. The recording head 5 is configured integrally or independently with a group of nozzles capable of recording six colors of ink. As inks to be used, cyan (C), magenta (M), yellow (Y), In addition to black (K), a total of six colors of light cyan (LC) and light magenta (LM) are employed for the purpose of reducing graininess and improving gradation.

  30A and 30B are recovery mechanisms. The recovery mechanisms 30 </ b> A and 30 </ b> B perform the suction operation of the recording head 5 using a pump (not shown) as a drive source through a cap provided therein. Further, a wiping mechanism (not shown) is provided, and the wiping operation of each discharge port surface of the recording head 5 can be performed using the wiping mechanism. Further, when the recording head 5 is not used, the recording head is also protected by the cap.

  Reference numeral 31 denotes an ink receiving box, which can receive the ink discharged by the preliminary discharge operation of the recording head 5 therein.

  When image data is input to the recording apparatus main body 2 from a host device (not shown), a single recording medium is fed into the recording apparatus main body 2 by a paper transport unit (not shown). The recording head 5 mounted on the carriage 1 ejects ink onto the fed recording medium while moving and scanning in a direction (main scanning direction) along the guide shaft 11. As a result, an image for one band is recorded on the recording medium. After the recording for one band is completed, the recording medium is conveyed by one band (or a predetermined distance) in a direction (sub-scanning direction) perpendicular to the main scanning direction by the paper conveying unit. In this way, images are sequentially recorded by alternately repeating the recording scan of the recording head 5 and the conveyance of the recording medium.

  An encoder film 12 for detecting the current position of the carriage 1 is disposed on the movement path of the carriage 1, and an encoder sensor mounted on the carriage 1 detects this. The carriage position detection mechanism also controls movement of the carriage 1 to the home position (position facing the recovery mechanism).

  In the recording head 5, 1280 ejection openings are arranged for one color at an arrangement density of 1200 dpi in the sub-scanning direction, and further, this ejection opening group is arranged for six colors in the main scanning direction. An electrothermal converter for heating the ink locally to cause film boiling and ejecting the ink from the ejection port by the pressure is provided in the nozzle communicating with each ejection port.

  FIG. 3 is a block diagram for explaining the configuration of a control system in the ink jet recording apparatus applied in the present embodiment.

  In the figure, each block in the print engine 220 is controlled by an MPU (Micro Processor Unit) 221 in accordance with a program stored in the ROM 227. The RAM 228 is used as a work area for the MPU 221 or an area for temporarily storing data. The MPU 221 can control the carriage drive system 223, the conveyance drive system 224, the recovery drive system 225, the print head drive system 226, and the like via an ASIC 222 (Application Specific Integrated Circuit). Further, the MPU 221 is configured to be able to read and write to the print buffer 229 and the mask buffer 230 via the ASIC 222.

  The print buffer 229 temporarily stores recording data converted into a format that can be transferred to the recording head. In the mask buffer 230, a mask pattern for multi-pass printing corresponding to the recording mode at that time is temporarily stored. When performing multi-pass printing, AND processing is performed between the print data stored in the print buffer 229 and the mask pattern data stored in the mask buffer 230, and the print head actually prints in each print scan. Determine the final recording data to be performed. Note that a plurality of types of mask patterns are stored in advance in the ROM 227, and corresponding mask patterns are read out corresponding to recording modes having different recording methods such as different numbers of multi-passes. In the case of a recording mode that does not require the mask pattern itself, such as 1-pass recording, the above processing relating to the mask pattern is not performed.

Next, the operation of each block when the actual recording operation is performed will be described.
The recording operation is started when image data is input to the reception buffer 250 of the print engine 220 from the host apparatus 200 connected to the outside of the recording apparatus main body 240. In addition to the recording data, the image data includes information necessary for recording such as recording quality and margin information. The print engine 220 analyzes the received image data and performs control corresponding to various information. Start. At this time, recording data, recording quality, media, margin information, and the like are processed by the MPU 221 via the ASIC 222 and further stored in the RAM 228. This information is then referred to as appropriate in the necessary situation and used to isolate the process. Further, the recording mode is determined based on the recording quality and media information, and the mask pattern of the corresponding recording mode is read out from the ROM 227 and written into the mask buffer 230.

  The recording data takes the form of index data already described, and has density information expressed in several stages as multi-value data. First, the MPU 221 performs processing for adding paper preliminary ejection data to the input recording data. The method for generating the paper preliminary ejection data added here and the addition method will be described in detail later. The recording data to which the paper preliminary ejection data is added becomes a data form that can be transferred to the recording head by HV (vertical / horizontal) conversion processing, and is written in the print buffer 229 at this stage.

  When a predetermined amount of recording data held in the print buffer 229 is accumulated, the MPU 221 performs a recording medium feeding operation by the transport driving system 224 via the ASIC 222 and further moves the carriage 1 by the carriage driving system 223. . Further, the recovery system is driven by the recovery drive system 225 to perform a necessary recovery operation before the recording operation. Further, an image output position and the like are set for the ASIC 222, and a recording operation is started.

  When the carriage 1 moves and reaches the recording start position set in the ASIC 222, the recording data held in the print buffer 229 is sequentially read in accordance with the ejection timing. At the same time, the mask pattern is read from the mask buffer 230. The read recording data and mask data are subjected to an AND (logical product) process, and then an index expansion process is performed in real time via the ASIC 222. As a result, the recording data is binarized and transferred to the recording head as it is. In the present embodiment, the mask process for multi-pass printing is performed at the stage and resolution before the print data is binarized in this way. Accordingly, recording / non-recording of recording data is determined in units of 2 × 2 matrix patterns. The recording head driving system 226 performs driving and ejection control of the recording head according to the transferred data.

  By repeating the series of processes described above, that is, the steps from the reception of image data from the host device 200 to the recording scan for one recording head, images are sequentially formed on the recording medium.

  FIG. 4 is a block diagram for explaining the flow of data processing performed by each of the host apparatus 200 and the recording apparatus main body 240.

  The host device 200 is preinstalled with a printer driver 250, which is software for controlling the recording device, and is activated when the user attempts to record a desired image. First, the printer driver 250 generates an image to be recorded as multi-value data (here, 8 bits) in 600 × 600 ppi RGB (red, green, blue) format. Next, color conversion processing 500 is performed from 8-bit RGB to 8-bit R′G′B ′ in order to make the image data correspond to the color space that can be output by the printing apparatus. Further, in order to correspond to the ink color used in the printing apparatus, 8-bit R′G′B ′ data is also converted into 8-bit cyan (C), magenta (M), yellow (Y), black (K), Color separation processing 510 is performed on light cyan (LC) and light magenta (LM). The above color conversion processing 500 and color separation processing 510 perform data conversion using a predetermined look-up table.

  Subsequently, a quantization process 520 for quantizing each color to 4 bits (5 gradations) is performed on C, M, Y, K, LC, and LM 8-bit data (256 gradations). As the quantization processing 520, a known multilevel error diffusion method or dither method can be applied. In the printer driver 250, in addition to the quantized data of 4 bits (5 gradations) for each color, information necessary for recording such as recording quality, media, and margin information is added, and then all of the data is recorded as image data. To 240.

  In the recording apparatus main body, a preliminary paper ejection additional process 530 is first performed on the received 4-bit data for each color. The recording data to which the preliminary paper ejection data has been added is subjected to a mask process if necessary, and then recording is performed while performing the index development process 540.

  FIG. 5 is a schematic diagram for explaining the index expansion processing 540 applied in the present embodiment. In general, the index expansion process reduces the processing load on multi-valued data for each color (here, C, M, Y, K, LC, and LM), and improves gradation and improves both speed and image quality. It is carried out for the purpose. In the present embodiment, index expansion is performed to convert 4-bit (5 gradations) data of 600 ppi into 1-bit (2 gradations) data of 1200 dpi. Therefore, the developed matrix size is 2 (horizontal) × 2 (vertical).

  As shown in FIG. 5, the 4-bit input data (“0000”, “0001”, “0010”, “0011”, “0100”) for five gradations of this embodiment has a matrix pattern ( 800, 801, 802, 803, 804) are set. Further, a matrix pattern 805 is set as output data for the input data “0101” separately from the five gradations of the recording data. This is a special matrix pattern for preliminary ejection on the paper surface that is provided so that preliminary ejection is uniformly applied to each nozzle. These matrix patterns may be stored in advance in the ROM in the recording apparatus main body, or may be downloaded from the host apparatus together with the recording data.

  The printer driver 250 inputs the above-described five gradation recording data (0000 to 0100). However, in the recording apparatus main body, the paper preliminary ejection data “0001” or “0101” is set to a predetermined value by the paper preliminary ejection additional processing 530. It is added to the recording data in order. The 600 ppi 4-bit data to which the paper preliminary ejection data is added is developed into matrix patterns 800 to 805 in accordance with the development rules shown in FIG. 5, and is output as 1200 dpi 1-bit (two gradations) data.

  FIG. 6 is a diagram illustrating an example of pixel positions to which the paper preliminary discharge data can be added in the paper preliminary discharge addition processing 530. Reference numerals 310 to 341 denote nozzles arranged on the recording head 300, and the number thereof is set to 32 here for the sake of simplicity. Each grid shown on the right side of the drawing indicates pixel positions on the print medium arranged at a resolution of 600 ppi equal to the print data input from the printer driver 250, and the grid filled in black performs preliminary ejection on the paper. The pixel position and the white grid represent the pixel positions where the preliminary ejection on the paper is not performed. Here, the origin (X0, Y0) of the pixel to which the paper preliminary ejection data is added is indicated as 360. When recording is actually performed, a logical sum is calculated between the presence / absence (1 or 0) of the recording data input at the pixel position and the presence / absence (1 or 0) of the preliminary ejection data on the paper, for example, When the recording data of the pixel of “0000” is “0000”, “0001” or “0101” of FIG. Further, by the subsequent index expansion, the output data becomes 801 or 805. As a result, at the origin 360, one dot is ejected by either the nozzle 310 or the nozzle 311.

  Similarly to the origin 360, the paper preliminary ejection data is added to the pixel 361 having coordinates (X0 + X1, Y + 1) moved by X1 pixels in the X direction and 1 pixel in the Y direction from the origin 360. In this case, one dot is ejected to the pixel 361 as a preliminary discharge on the paper by either the nozzle 312 or the nozzle 313. Similarly, at the coordinates (X0 + 2 × X1, Y0 + 2) 362 moved from this pixel position 361 by X1 pixels in the X direction and one pixel in the Y direction, one dot is preliminarily ejected by the nozzle 314 or the nozzle 315. Are discharged. Further, at coordinates (X0 + 3 × X1, 3) moved from 362 by X1 pixels in the X direction and 1 pixel in the Y direction, one dot is ejected as preliminary ejection on the paper by either the nozzle 316 or the nozzle 317. If Y1 is set so that Y0 + 3 = Y1-1, as shown in the figure, the paper surface preliminary ejection data ejected from either the next nozzle 318 or nozzle 319 is (X0 + 1, Y1) is set.

  According to the rules described above, when the pixel positions to which the paper preliminary ejection data is added are arranged, as shown in FIG. 6, an area of 4 × X1 pixels in the X direction and 4 × Y1 pixels in the Y direction is defined as one cycle. Uniform distribution can be obtained. In addition, it is possible to make the establishment of performing the preliminary ejection on the paper in the 32 nozzles almost equal.

  In FIG. 6, the pixel position to be preliminarily ejected on the paper surface can be set by four parameters of the origin coordinates (X0, Y0) and parameters X1 and Y1 for determining the array period. However, the arrangement method shown here is one example applicable to this embodiment, and does not limit the present invention. In order to realize other paper surface preliminary ejection patterns, more parameters may be added, or conversely, parameters may be deleted for simplification.

  By the way, as already described, in the case of performing multi-pass printing in the present embodiment, mask processing is performed on multi-value printing data with the paper surface preliminary ejection data added. Usually, in a recording apparatus to which an index method is applied, a mask is often applied to binary data after index expansion. However, in this configuration, even if the paper preliminary ejection data is added so that the number of ejections is equalized at each nozzle as in the present embodiment, there is a possibility that the data will be thinned out by the thinning mask. Therefore, in the present embodiment, the resolution for adding the paper preliminary discharge data and the resolution of the thinning mask are made equal, so that the addition position of the paper preliminary discharge data is taken into consideration while considering the form of the thinning mask (or vice versa). ).

  In this case, if the same paper surface preliminary ejection pattern is applied in all recording modes in the same manner, in the recording mode with a large number of multi-passes, the number of paper surface preliminary ejections performed in each recording scan is reduced. The purpose of preliminary ejection cannot be fulfilled. Therefore, when different mask patterns are applied even if the number of different multi-passes or the same number of multi-passes is applied, an optimal paper surface preliminary discharge pattern is selected according to the mask pattern so that a substantially constant number of paper surface preliminary discharges can be performed in any printing scan. It is desirable to have a configuration in which

  FIG. 7 is a diagram for explaining a state of signal value conversion actually performed on a certain pixel when adding paper preliminary ejection data in the present embodiment. Here, in order to simplify the description, one light cyan (LC) color will be described.

  In FIG. 7, reference numeral 1000 denotes one pixel to which the paper preliminary discharge data is added according to the above-described paper preliminary discharge pattern. Of course, the resolution is 600 ppi both vertically and horizontally. Reference numerals 1010-a and 1010-b represent 4-bit LC recording data corresponding to the pixel 1000 to which the preliminary ejection data for the page is added. Further, 1020-a, 1020-b, and 1020-c represent print data obtained as a result of adding preliminary ejection data to LC print data.

  The original LC recording data 1010-a and 1010-b is 4-bit data of 5 gradations and has a value of “0000”, “0001”, “0010”, “0011”, or “0100”. have. If this is “0000” as in 1010-a, it is determined that the preliminary ejection data for the paper is added, and the LC 4-bit recording data is 1020-a (“0001”) or 1020-c ( "0101"). Further, when it has a value of “0001” to “0111” as in 1010-b, the paper preliminary ejection data is not added, and the LC recording data 1010-b remains as it is after the preliminary ejection data is added. The recorded data is 1020-b. The recording data after adding the paper preliminary ejection data has values of 0001 to 0101, and each signal value is developed into the patterns indicated by 801 to 805 in FIG. 5 by the subsequent index processing. . Actually, two patterns are used as the preliminary ejection pattern on the paper, ie, a pattern 801 converted from “0001” of 1020-a and a pattern 805 converted from “0101” of 1030-c.

  As described above, by using the paper preliminary ejection pattern shown in FIG. 6 and the like, the probability of performing preliminary ejection can be made almost equal to almost all pixel positions. However, since two nozzles correspond to each pixel shown in FIG. 6, for example, if the matrix pattern developed by index processing is only 801, odd-numbered nozzles are not used at all. It will disappear. Therefore, in the present embodiment, for example, the matrix pattern 801 is associated with the origin pixel 360, and the matrix pattern 805 is added to the additional pixel 365 of the next paper preliminary ejection data located on the same Y coordinate line. It corresponds. In this way, the nozzles 310 and the nozzles 311 can be alternately and almost uniformly ejected by sequentially exchanging the matrix pattern to be applied to a plurality of pixels on the same line. Furthermore, by applying such a rule to other lines, it is possible to make the probability of performing preliminary ejection almost equal to all nozzles.

  As described above, according to the present embodiment, content (“0101”) different from the recorded data is inputted to the inputted multi-value (five types) recorded data (“0000” to “0100”). The new signal value that is included is added as preliminary paper ejection data. At this stage, there are six types of recording signal values, “0000” to “0101”. In the subsequent index expansion, different matrix patterns corresponding to the above six types of signal values are converted into binary recording data. Through the above steps, the number of ejections in the same recording scan can be maintained at a substantially steady value in a plurality of nozzles arranged in the recording head, and stable ejection can be maintained.

(Second Embodiment)
The second embodiment of the present invention will be described below. In the present embodiment, a method for adding paper preliminary ejection data to an inkjet recording apparatus including an image controller will be described.

  FIG. 8 is a block diagram showing the configuration of the control system in the present embodiment. In FIG. 8, each block indicated by the same reference numeral as in FIG. 3 plays the same role as in the first embodiment.

  The image controller 210 notifies the print engine 220 of a control command in accordance with a command from an operation unit (not shown) of the host apparatus 200 or the recording apparatus main body 240. During recording, the recording data received from the host device 200 is analyzed and developed, and binarization processing is performed on the recording data of each color. The print engine 220 performs an actual recording operation according to the control command and binarized recording data sent from the image controller 210.

  The image controller 210 and the print engine 220 are connected by a dedicated interface. The image controller 210 transmits a command to notify the print engine 220 of a control command, and notifies the image controller 210 of a change in the state of the recording apparatus. Status communication and communication such as transfer of recording data from the image controller 210 to the print engine 220 are performed.

  Next, the operation of each block when the actual recording operation in FIG. 8 is performed will be described.

  The recording operation is started when image data is input to the image controller 210 from the host device 200 connected to the outside of the recording apparatus main body. The image data includes information necessary for recording such as recording quality and margin information in addition to multi-valued recording data. The image controller 210 analyzes the image data received from the host device 200 and records it. Necessary information such as quality and margin information is generated. Further, after analyzing and developing the recording data and adding the paper preliminary ejection data, an operation of converting each color into binary data is started. The recording data expansion process performed here is the same as that in the first embodiment. Information necessary for recording by the print engine 220 such as recording quality and margin information is notified to the print engine 220 as it is. In the print engine 220, the notified information is processed by the MPU 221 via the ASIC 222 and held in the RAM 228. This information is then referred to in the required situation and used to isolate the process. Further, the mask pattern is written into the mask buffer 230 in the print engine 220 as necessary.

  When the notification of necessary information to the print engine 220 is completed, the image controller 210 starts a recording data expansion process and a process of transferring the processed recording data to the print engine 220. The print engine 220 stores the transferred binary recording data in the print buffer 229 one after another.

  When the data held in the print buffer 229 is accumulated up to the amount required for one recording scan, the MPU 221 conveys the sheet by the conveyance drive system 224 via the ASIC 222, and the carriage drive system 223 carries the carriage. Move 1 Further, the recovery system is driven by the recovery drive system 225 to perform a necessary recovery operation before the recording operation. Further, the image output position and the like are set in the ASIC 222, the carriage 1 is driven, and the recording operation is started.

  When the carriage 1 moves and reaches the recording start position set in the ASIC 222, binary recording data to which the paper preliminary ejection pattern is added is sequentially read from the print buffer 229 in accordance with the ejection timing, and the recording head. Forwarded to Thereafter, the print head is driven under the control of the head drive system 226, and ink is ejected in accordance with the transferred binary print data. As described above, by repeating the processing from the reception of the recording data from the image controller 210 to the ink ejection by the recording head, images are sequentially formed on the recording medium.

  FIG. 9 is a block diagram for explaining the flow of data processing performed by each of the host apparatus 200 and the recording apparatus main body 240.

  The host device 200 is preinstalled with a printer driver 250, which is software for controlling the recording device, and is activated when the user attempts to record a desired image. The printer driver 250 converts the image to be recorded into 600 × 600 ppi RGB (red, green, blue) format or KCMY (black, cyan, magenta, yellow) format multi-value data (here, 8 bits each). It is generated and transferred to the image controller 210 of the recording apparatus main body.

  In the image controller 210, when the received data is in the RGB format, in order to make the image data correspond to the color space that can be output by the recording apparatus, the 8-bit RGB is similarly converted to 8-bit R'G'B '. A color conversion process 500 is performed. Further, in order to correspond to the ink color used in the printing apparatus, 8-bit R′G′B ′ data is also converted into 8-bit cyan (C), magenta (M), yellow (Y), black (K), Color separation processing 510 is performed on light cyan (LC) and light magenta (LM). On the other hand, when the data received by the image controller 210 is in the KCMY format, the color separation processing 510 is immediately performed without performing the color conversion processing 500. The above color conversion processing 500 and color separation processing 510 perform data conversion using a predetermined look-up table. The lookup table applied here may be stored in advance in the ROM 227 of the recording apparatus main body, or may be transferred from the host apparatus 200 together with the recording data.

  Subsequently, in the image controller 210, quantization processing 520 for quantizing C, M, Y, K, LC, and LM 8-bit (256 gradations) data into 4-bit (5 gradations) data for each color. Is done. As the quantization processing 520, a known multilevel error diffusion method or dither method can be applied.

  Further, a paper surface preliminary discharge addition process 530 is performed on the quantized 4-bit data of each color. If the multi-pass printing is performed on the recording data to which the paper preliminary ejection data is added, the mask process is applied at this stage.

  Next, the index development processing 540 converts the recording data into binary data of 1 bit for each color of K, LC, LM, C, M, and Y. As the index expansion method, the one shown in FIG. 5 can be applied as in the first embodiment. The converted 1-bit data is transferred to the printer engine 220 and recorded.

  As described above, according to the present embodiment, image processing, quantization processing, addition of paper preliminary ejection data, and binarization processing are performed inside the image controller 210 of the recording apparatus main body, so that processing in the host device can be performed. The load can be reduced. Therefore, in addition to the effect obtained in the first embodiment, the effect of improving the throughput can be obtained in the entire recording system including the host device and the recording device.

  In the above description, the multi-pass mask pattern is stored in the mask buffer 230 of the print engine 220 while the image controller 210 performs mask processing at a multi-value stage. However, the present embodiment is not limited to this. Unlike the first embodiment, for example, the print engine 220 may perform multi-pass mask processing on print data that has been binarized by the image controller 210. The effect is obtained.

(Third embodiment)
The third embodiment of the present invention will be described below. In the present embodiment, it is assumed that index processing corresponding to a plurality of different matrix patterns with respect to the same gradation value is performed for recording data other than preliminary ejection on the paper surface. Also in the present embodiment, as in the above-described embodiment, 8-bit multi-value data represented by 256 gradations is quantized into 4-bit multi-value data represented by 5 gradations. Further, as the quantization method, a known dither or multilevel error diffusion method is used.

  FIG. 10 is a diagram schematically illustrating an example of a matrix pattern in the index method of the present embodiment. Here, as in the above-described embodiment, 600 × pi image data having five gradation values is used to generate binary print data of 1200 × 1200 dpi by using a matrix pattern of 2 areas × 2 areas. An example is shown.

  Reference numerals 0000 to 1100 arranged on the left side of the drawing indicate recording data included in each pixel. The recording data is composed of 4 bits and has 5 gradation values from 0 to 4. In this embodiment, a plurality of recording data is prepared for the same gradation value. It has become. For example, the recording data “0001”, “0101”, “0110”, and “0111” are all recording data corresponding to the gradation value 1. 900 to 911 shown on the right side of the recording data indicate matrix patterns developed corresponding to each recording data. A plurality of recording data and matrix patterns may correspond to one gradation value, but the recording data and the matrix pattern are always in a one-to-one correspondence.

  Among the five gradations, for the gradation value 0 and gradation value 4, the dot arrangement of the matrix pattern is uniquely determined as whether all are recorded or all are recorded. The matrix pattern has one type for the gradation value (pattern 900 for “0000”, pattern 904 for “0100”). However, for other gradation values, a plurality of input data are prepared, and the plurality of input data are sequentially output while being switched by a predetermined method at the stage of quantization processing. For example, in the case of a gradation value of 1, “0001”, “0101”, “0110” and “0111” are sequentially output according to some method, whether cyclic or random. is there. Similarly, for gradation value 2, two types, “0010” and “1000”, and for gradation value 3, four types, “0011”, “1001”, “1011”, “1100” Output sequentially according to a predetermined method. Here, the predetermined method may be, for example, switching in order at a constant cycle, or may be a method of switching randomly using a pseudo random number.

  Regardless of the method, according to the present embodiment, a plurality of matrix patterns are not associated with one recording data as in the case of FIG. A plurality of gradation values are prepared for one gradation value. That is, instead of periodically selecting a matrix pattern at the time of index expansion processing 540 in FIG. 4 or FIG. 5, recording data for the target pixel is determined while simultaneously considering neighboring pixels at the stage of quantization processing 520. It can be done. Therefore, even in a situation where the preliminary ejection data on the paper is added, in order to cause the target nozzle to perform a predetermined number of ejections, an appropriate number of appropriate patterns are used to suppress the visibility of the preliminary ejection on the paper itself. It is possible to add to any position. Specifically, for example, four types of print data values “0001”, “0101”, “0110”, and “0111” corresponding to the gradation value 1 are equally used in consideration of print data in the vicinity. It may be added by switching at a predetermined cycle so that

  As described above, according to the present embodiment, when quantizing, a plurality of recording data is output while being switched for the same gradation value, and at the same time, different recording data is switched as the preliminary ejection data on the paper. However, it can be added to the recording data. Therefore, it becomes possible to perform preliminary ejection on the paper surface evenly with respect to the used nozzles and without reducing the image quality.

  In the above description, an ink jet recording system in which an electrothermal transducer is provided in a nozzle has been described as a preferred example for realizing high density recording with small droplets. Is not limited to this method. Even if the ink is ejected by another method, the effect of the present invention can be sufficiently obtained if the ink jet recording system performs recording from a plurality of recording elements using the index method.

  The present invention can be used in an ink jet recording apparatus that performs recording on a recording medium using a plurality of recording elements.

It is the figure which represented typically an example of the matrix pattern of the general index expansion | deployment in a prior art. 1 is a top view for explaining a schematic configuration of an ink jet recording apparatus applicable to an embodiment of the present invention. FIG. 3 is a block diagram for explaining a configuration of a control system in the ink jet recording apparatus applied to the first embodiment of the present invention. It is a block diagram for demonstrating the flow of the data processing in the 1st Embodiment of this invention. It is a schematic diagram for demonstrating the index expansion | deployment process applied in the 1st Embodiment of this invention. 6 is a diagram illustrating an example of pixel positions to which paper preliminary ejection data can be added when performing paper preliminary ejection in the recording apparatus according to the first embodiment of the present invention. FIG. It is a figure for demonstrating the mode of the signal value conversion actually performed when adding the paper surface preliminary discharge data in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the control system in the 2nd Embodiment of this invention. It is a block diagram for demonstrating the flow of the data processing in the 2nd Embodiment of this invention. It is the figure which represented typically an example of the matrix pattern in the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carriage 2 Apparatus main body 5 Recording head 11 Guide shaft 12 Encoder film 13 Belt 30 Recovery mechanism 31 Ink receiving box 200 Host apparatus 210 Image controller 220 Print engine 221 MPU
222 ASIC
223 Carriage drive system 224 Transport drive system 225 Recovery drive system 226 Printhead drive system 227 ROM
228 RAM
229 Print buffer 230 Mask buffer 240 Recording device 250 Printer driver 300 Recording head 310 to 341 Nozzle 360 Origin pixel 361 to 365 Paper surface preliminary ejection data additional pixel 500 Color conversion processing 510 Color separation processing 520 Quantization processing 530 Paper preliminary ejection additional processing 540 Index expansion processing 700 to 719 Matrix pattern 800 to 805 Matrix pattern 900 to 911 Matrix pattern 1000 Preliminary ejection data addition pixel 1010 LC recording data 1020 Recording data after addition of LC preliminary ejection data

Claims (12)

Recording is performed by ejecting ink from a plurality of recording elements to a recording medium, and preliminary recording is performed to preliminarily eject ink from the recording elements to the recording medium in order to maintain good ink ejection performance of the recording elements. An ink jet recording system using an ink jet recording apparatus capable of performing a discharge process,
Quantization means for quantizing one pixel into recording data capable of expressing gradation values in several stages;
It is determined whether or not to perform preliminary ejection processing on the recording medium for the pixel, and for the pixel to be performed, a predetermined signal value is newly selected from a plurality of types of signal values, and the pixel is selected. Preliminary ejection data adding means for adding to the recording data obtained by the quantization means;
The recording data created by the preliminary ejection data adding means is binarized by associating it with a matrix pattern that defines dot recording / non-recording in each of a plurality of areas constituting the region corresponding to the one pixel. Index expansion means for processing;
Recording means for ejecting ink from a plurality of recording elements in accordance with binary recording data obtained by the index development means, and the plurality of types of signal values added by the preliminary ejection data addition means include the index development The inkjet recording system, wherein the matrix patterns having the same number of dots and different dot arrangements correspond to each other by the means.   The plurality of types of signal values added by the preliminary ejection data adding unit are converted into the matrix patterns having the smallest dot recording number and different dot arrangements by the index developing unit, respectively. The ink jet recording system according to claim 1.   3. The ink jet recording system according to claim 1, wherein the matrix pattern having one kind of dot arrangement corresponds to one kind of signal value input to the index developing means.   3. The ink jet recording system according to claim 1, wherein the matrix pattern having a plurality of types of dot arrangements corresponds to one type of signal value input to the index developing unit.   5. The one type of signal value input to the index development means is output while the matrix patterns of the plurality of types of dot arrangement are sequentially switched at a predetermined cycle. Inkjet recording system.   5. The one type of signal value input to the index development means is output while the matrix pattern of the plurality of types of dot arrangement is switched randomly based on a pseudo random number. The inkjet recording system described. The inkjet recording system includes the inkjet recording apparatus and a host computer,
The host computer color-converts a multi-value signal representing luminance into a multi-value signal representing density, and quantizes the multi-value signal representing density and converts it into a multi-value signal representing lower level density. 7. The ink jet recording system according to claim 1, further comprising: means; and means for transmitting a multilevel signal representing the low level density to the ink jet recording apparatus. The ink jet recording system has a printer controller and a print engine inside the ink jet recording apparatus,
The printer controller color-converts a multi-value signal representing luminance into a multi-value signal representing density, and converts the multi-value signal representing density into a multi-value signal representing lower level density by quantizing the multi-value signal representing density. 7. The ink jet recording system according to claim 1, further comprising: means and means for transmitting a multilevel signal representing the low level density to the print engine. An ink jet recording system using an ink jet recording apparatus capable of performing a preliminary discharge process for preliminarily discharging ink from a recording element to a recording medium in order to maintain good discharge performance,
Quantization means for quantizing one pixel into multi-value recording data capable of expressing gradation values in several stages;
Preliminary ejection data adding means for adding multilevel preliminary ejection data to the multilevel recording data quantized by the quantization means;
A matrix in which multi-value recording data to which multi-value pre-discharge data has been added by the pre-discharge data adding means determines whether or not dots are recorded in each of a plurality of areas constituting the area corresponding to the one pixel. Binarization means for performing binarization processing by corresponding to the pattern,
An inkjet recording system, wherein a plurality of matrix patterns having the same number of dots and different dot arrangements are used as the matrix pattern corresponding to the multi-value preliminary ejection data added by the preliminary ejection data adding means. Recording is performed by ejecting ink from a plurality of recording elements to a recording medium, and preliminary recording is performed to preliminarily eject ink from the recording elements to the recording medium in order to maintain good ink ejection performance of the recording elements. An inkjet recording method using an inkjet recording apparatus capable of performing a discharge process,
A quantization process for quantizing one pixel into recording data capable of expressing gradation values in several stages;
It is determined whether or not to perform preliminary ejection processing on the recording medium for the pixel, and for the pixel to be performed, a predetermined signal value is newly selected from a plurality of types of signal values, and the pixel is selected. A preliminary ejection data adding step to be added to the recording data obtained by the quantization step;
The recording data created by the preliminary ejection data adding step is binarized by making it correspond to a matrix pattern that defines dot recording / non-recording in each of a plurality of areas constituting the region corresponding to the one pixel. An index expansion process for processing,
A recording step of ejecting ink from a plurality of recording elements according to binary recording data obtained by the index expansion step, and the plurality of types of signal values added by the preliminary discharge data adding step are the index expansion The inkjet recording method, wherein the matrix patterns having the same number of dots and different arrangements correspond to each other depending on the process.   10. A program applicable to the ink jet recording method according to claim 9, wherein at least one of the quantization step, the preliminary discharge adding step, and the index expanding step is performed by a host computer connected to the ink jet recording apparatus. A program for running. An ink jet recording method using an ink jet recording apparatus capable of performing a preliminary ejection process in which ink is preliminarily ejected from a recording element to a recording medium in order to maintain good ejection performance,
A quantization process for quantizing one pixel into multi-valued recording data capable of expressing gradation values in several stages;
A preliminary ejection data adding step of adding multilevel preliminary ejection data to the multilevel recording data quantized in the quantization step;
A matrix in which multi-value recording data to which multi-value preliminary ejection data is added in the preliminary ejection data adding step is set to record / non-record dots in each of a plurality of areas constituting the area corresponding to the one pixel. A binarization process for performing binarization processing by making it correspond to the pattern,
An inkjet recording method, wherein a plurality of matrix patterns having the same number of dots and different dot arrangements are used as matrix patterns corresponding to multi-value preliminary ejection data added in the preliminary ejection data adding step.

Images