JP2012011727A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus and recording method, which can record a uniform image having no uneven glossiness and image clarity.SOLUTION: A recording sequence of colored ink and image quality improving liquid to a predetermined region is varied based on image data for the predetermined region of a recording medium. Consequently, a uniform image can be recorded in which the glossiness and the image clarity are adjusted to a middle level, in various density regions tending to be mutually different in glossiness and image clarity.

Description

  The present invention relates to an inkjet recording apparatus that records an image by applying both colored ink and an image quality improving liquid for improving image quality to a recording medium. In particular, the present invention relates to an ink jet recording method for preventing unevenness in glossiness and image clarity in an image after recording.

  Ink jet recording apparatuses are required to record high-quality images on various recording media. In particular, when recording is performed on glossy paper having gloss, uniform glossiness and high image clarity are required for the entire image. However, since the inkjet recording apparatus records colored ink in accordance with image data, a relatively large area, a small area, or an area where no colored ink is applied is distributed on the same recording medium. Then, the variation in the amount of colored ink applied may be perceived as uneven glossiness.

  On the other hand, in Patent Document 1, in addition to colored ink, an image quality improving liquid for improving the glossiness of an image and the like is prepared, and the amount of the image quality improving liquid applied is variable according to the amount of colored ink applied. A configuration is disclosed. In Patent Document 1, it is noted that the region having a relatively large amount of colored ink has a higher gloss than the region having a relatively small amount, and more image quality is applied to a region having a small amount of colored ink applied. Control is performed so as to apply the improving liquid. By such a method, the glossiness of the region where the amount of colored ink applied is small can be brought close to the glossiness of the region where the amount of colored ink applied is large, and unevenness of the glossiness in the image can be reduced.

Japanese Patent No. 4003760

  However, only the amount of the image quality improving liquid corresponding to the amount of the colored ink is adjusted by the method of Patent Document 1, and the recording method, in particular, the order of recording the colored ink and the image quality improving liquid is not controlled. There wasn't. The order of recording the colored ink and the image quality improving liquid on the recording medium affects the unevenness of the image surface. Therefore, if there are locations where the color improvement ink is recorded after recording the colored ink and locations where the color ink is recorded after the image quality improvement liquid is recorded, sufficient smoothness cannot be obtained on the image surface, and sufficient mapping is achieved. I could not get sex.

  The present invention has been made to solve the above problems. Therefore, an object of the invention is to provide an ink jet recording apparatus capable of recording a uniform image without unevenness in glossiness and image clarity.

  For this purpose, the present invention uses a recording head that discharges an image quality improving liquid that does not contain a color ink containing a color material and an image recorded with the color ink and that improves the image quality of the image. In an inkjet recording apparatus that records an image on a recording medium by moving the medium, the recording order of the colored ink and the image quality improving liquid for the predetermined area is changed based on image data for the predetermined area of the recording medium. A recording control means is provided.

  According to the present invention, it is possible to switch between mixed printing and post printing in association with image data of each pixel at each printing scan. This makes it possible to record a uniform image in which both glossiness and image clarity are adjusted to “medium” in various density regions that tend to have different glossiness and image clarity.

(A) And (b) is a perspective view of the inkjet recording device which can be used by this invention. It is a block diagram which shows the control structure of the inkjet recording device which can be used by this invention. It is an example of the inkjet recording head which can be used by this invention. It is a block diagram for demonstrating the process of the conversion process of image data. It is the figure which showed the structural example of image data information and recording control information. It is a figure explaining the dot arrangement pattern of 17 gradations. It is a figure for demonstrating multipass printing typically. (A)-(d) is a figure explaining the measuring method of glossiness and haze. It is a figure for demonstrating a mode that image clarity and glossiness change according to a gradation. (A)-(c) is a figure for demonstrating a mode that the order which records colored ink and an image quality improvement liquid influences the smoothness of the surface of a recording medium. FIG. 3 is a diagram illustrating an arrangement state of ejection port arrays of a recording head. It is a flowchart for demonstrating the selection process of a mask pattern. It is a figure for demonstrating matching a total recording duty and a recording method. (A)-(c) is a figure which shows the mask pattern B which implement | achieves post-printing when performing 1 pass bidirectional | two-way. (A)-(c) is a figure which shows the mask pattern A which implement | achieves mixed printing when performing 1 pass bidirectional | two-way. (A) And (b) is a figure for demonstrating the mask pattern B which implement | achieves post-printing at the time of performing two-pass bidirectional | two-way. (A) And (b) is a figure for demonstrating the mask pattern A which implement | achieves mixed printing when performing two-pass bidirectional | two-way. FIG. 6 is a diagram illustrating mixed printing or post-printing recording settings for a combination of total printing duty and the number of inks. FIG. 6 is a diagram illustrating a setting example of mixed printing or post-printing recording with respect to a combination of recording duties of colored inks. (A) And (b) is a figure which shows threshold value TL ^* defined for every hue and the positional relationship of the hue in color space. It is a block diagram for demonstrating the process of the conversion process of image data. (A)-(c) is a figure which shows the method of producing | generating mask selection information from RGB data. It is another example of a recording head that can be used in the present invention. (A)-(d) is a figure which shows the mask pattern applicable to Example 6. FIG. It is another example of a recording head that can be used in the present invention.

[Example 1]
1A and 1B are perspective views of an ink jet recording apparatus that can be used in an embodiment of the present invention. FIG. 1A is a schematic perspective view, and FIG. 1B shows a main internal mechanism. During use, the paper feed tray 12 and the paper discharge tray 7 are opened as shown in FIG. Then, one of the recording media stacked on the paper feed tray 12 is fed into the recording apparatus, and after recording is performed, the paper is ejected to the paper ejection tray 7.

  Referring to FIG. 1B, the recording head 1 mounted on the carriage 5 ejects ink from the nozzles while reciprocating along the guide shaft 3 and the guide rail 4 in the directions of arrows A1 and A2, and the recording medium An image is formed on S. The recording head 1 has, for example, a plurality of nozzle groups corresponding to different colors of ink and image quality improving liquid. In this embodiment, the colored inks are cyan (C), magenta (M), yellow (Y), black (K), light cyan (LC), light magenta (LM), red (R), and gray (Gray) light gray. 9 colors of (LGray). In addition, an image quality improving liquid (CL) for improving the image quality is also prepared. Each ink is stored in an independent ink tank 6 and supplied to the recording head 1 from here.

  The carriage 5 is guided and supported in the A1 and A2 directions (main scanning direction) by the guide rail 4 and the guide shaft 3, while the driving force of the carriage motor 11 is transmitted through the timing belt 17 in the A1 and A2 directions. Moving. When the carriage 5 moves, the encoder sensor 21 provided in the carriage 5 detects a linear scale (not shown) arranged in parallel with the moving direction of the carriage 5 to determine the current position of the carriage 5. While the carriage 5 is moving in the main scanning direction, the recording head 1 mounted on the carriage 5 ejects ink according to the recording signal and records an image for one line on the recording medium S. A platen 2 is provided on the back surface of the recording medium in a region where recording is performed by the recording head 1, and the distance between the ejection port surface of the recording head 1 and the recording medium S is kept parallel and constant. When the recording main scan for one line by the recording head is completed, the recording medium S is conveyed by an amount corresponding to the recording width of the recording head 1 in the B direction (sub scanning direction) intersecting the A direction.

  The conveyance of the recording medium S is performed by the conveyance roller 16 and the pinch roller 15 that pinch the recording medium S from the front and back surfaces following the rotation of the linear wheel 20 using the conveyance motor 13 as a drive source. An image is recorded on the recording medium S step by step by alternately repeating the recording main scanning by the recording head 1 and the conveying operation of the recording medium S.

  A recovery unit 14 and a head cap 10 for maintaining the recording head 1 are provided at positions outside the recording area within the movable area of the carriage 5. For example, when a suction pump (not shown) included in the recovery unit 14 is operated in a state where the head cap 10 caps the ejection port surface of the recording head 1, ink containing unnecessary bubbles or foreign matters inside the recording head 1 is operated. Is forcibly discharged.

  FIG. 2 is a block diagram for explaining a control configuration of the ink jet recording apparatus used in this embodiment.

  The controller 100 is a main control unit and includes an ASIC 101 in the form of a microcomputer, a ROM 103, and a RAM 105. The ROM 103 stores a dot arrangement pattern and a mask pattern, which will be described later, other fixed data, and various programs. The RAM 105 provides an area for developing image data, a work area, and the like. The ASIC 101 reads a program from the ROM 103 and executes a series of processes from recording image data to a recording medium. For example, as characteristic processing of the present invention, image data is divided by selecting one of a plurality of mask patterns stored in the ROM 103 from information corresponding to the recording duty, and each recording main scan (pass) is divided. Generate recorded data.

  The host device 110 is an image data supply source (a computer that creates and processes data such as images related to printing, or may be in the form of a reader unit for image reading, etc.). Image data, other commands, status signals, and the like are transmitted / received to / from the controller 100 via the interface (I / F) 112.

  The head driver 140 is a driver that drives the recording head 1 according to print data or the like. The motor driver 150 is a driver that drives the carriage motor 11, and the motor driver 160 is a driver that drives the carry motor 13.

  Next, components of the colored ink and the image quality improving liquid used in this embodiment and the manufacturing method will be described. First, each component constituting the ink will be described.

(Aqueous medium)
The ink used in the present invention is preferably an aqueous medium containing water and a water-soluble organic solvent. The content (% by mass) of the water-soluble organic solvent in the ink is preferably 3.0% by mass or more and 50.0% by mass or less based on the total mass of the ink. The water content (% by mass) in the ink is preferably 50.0% by mass or more and 95.0% by mass or less based on the total mass of the ink.

  Specifically, for example, the following water-soluble organic solvents can be used. C1-C6 alkyl alcohols, such as methanol, ethanol, propanol, propanediol, butanol, butanediol, pentanol, pentanediol, hexanol, hexanediol, and the like. Amides such as dimethylformamide and dimethylacetamide. Ketones or ketoalcohols such as acetone and diacetone alcohol. Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols having an average molecular weight of 200, 300, 400, 600 and 1,000 such as polyethylene glycol and polypropylene glycol. Alkylene glycols having an alkylene group having 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; Lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate. Lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether. N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like. The water is preferably deionized water (ion exchange water).

(Pigment)
It is preferable to use carbon black or an organic pigment as the colorant. The pigment content (% by mass) in the ink is preferably 0.1% by mass or more and 15.0% by mass or less based on the total mass of the ink.

  For the black ink (Bk1), it is preferable to use carbon black such as furnace black, lamp black, acetylene black, and channel black as a pigment. Specifically, for example, the following commercially available products can be used. Ray Van: 7000, 5750, 5250, 5000ULTRA, 3500, 2000, 1500, 1250, 1200, 1190ULTRA-II, 1170, 1255 (above, Colombia). Black Pearls L, Legal: 330R, 400R, 660R, Mogul L, Monak: 700, 800, 880, 900, 1000, 1100, 1300, 1400, 2000, Vulcan XC-72R (above, manufactured by Cabot). Color Black: FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex: 35, U, V, 140U, 140V, Special Black: 6, 5, 4A, 4 (above, manufactured by Degussa). No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (above, manufactured by Mitsubishi Chemical). Carbon black newly prepared for the present invention can also be used. Of course, the present invention is not limited to these, and any conventional carbon black can be used. Further, the material is not limited to carbon black, and magnetic fine particles such as magnetite and ferrite, titanium black, and the like may be used as a pigment.

  For colored inks, the following organic pigments can be used. Water-insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow and pyrazolone red. Water-soluble azo pigments such as Ritolol Red, Helio Bordeaux, Pigment Scarlet, and Permanent Red 2B. Derivatives from vat dyes such as alizarin, indanthrone and thioindigo maroon. Phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green. Quinacridone pigments such as quinacridone red and quinacridone magenta. Perylene pigments such as perylene red and perylene scarlet. Isoindolinone pigments such as isoindolinone yellow and isoindolinone orange. Imidazolone pigments such as benzimidazolone yellow, benzimidazolone orange, and benzimidazolone red. Pilanthrone pigments such as pyranthrone red and pyranthrone orange. Indigo pigments, condensed azo pigments, thioindigo pigments, diketopyrrolopyrrole pigments. Flavanthrone yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianslaquinonyl red, dioxazine violet, etc. Of course, the present invention is not limited to these.

  Moreover, when an organic pigment is shown by a color index (CI) number, the following can be used, for example. C. I. Pigment Yellow: 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 97, 109, 110, 117, 120, 125, 128, 137, 138, 147, 148, 150, 151, 153 154, 166, 168, 180, 185, etc. C. I. Pigment Orange: 16, 36, 43, 51, 55, 59, 61, 71, etc. C. I. Pigment Red: 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175, 176, 177, 180, 192, etc. 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 272, etc. C. I. Pigment violet: 19, 23, 29, 30, 37, 40, 50, and the like. C. I. Pigment Blue: 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, and the like. C. I. Pigment Green: 7, 36 etc. C. I. Pigment Brown: 23, 25, 26, etc. Of course, the present invention is not limited to these.

(Dispersant)
As the dispersant for dispersing the pigment as described above in the aqueous medium, any resin having water solubility can be used. Of these, those having a weight average molecular weight of 1,000 to 30,000, more preferably 3,000 to 15,000 are preferred. The content (% by mass) of the dispersant in the ink is preferably 0.1% by mass or more and 5.0% by mass or less based on the total mass of the ink.

  Specifically, for example, the following can be used as the dispersant. Monomers of styrene, vinyl naphthalene, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid, maleic acid, itaconic acid, fumaric acid, vinyl acetate, vinyl pyrrolidone, acrylamide, or derivatives thereof A polymer. In addition, it is preferable that at least one monomer constituting the polymer is a hydrophilic monomer, and a block copolymer, a random copolymer, a graft copolymer, or a salt thereof may be used. good. Alternatively, natural resins such as rosin, shellac and starch can be used. These resins are preferably soluble in an aqueous solution in which a base is dissolved, that is, an alkali-soluble type.

(Surfactant)
In order to adjust the surface tension of the ink constituting the ink set, it is preferable to use a surfactant such as an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant. Specifically, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenols, acetylene glycol compounds, acetylene glycol ethylene oxide adducts, and the like can be used.

(Other ingredients)
In addition to the above-described components, the ink constituting the ink set may contain a moisturizing solid content such as urea, urea derivatives, trimethylolpropane, and trimethylolethane in order to maintain the moisturizing property. The content (% by mass) of the moisturizing solid content in the ink is 0.1% by mass or more and 20.0% by mass or less, further 3.0% by mass or more and 10.0% by mass or less based on the total mass of the ink. It is preferable to do. In addition to the above-described components, the ink constituting the ink set includes a pH adjuster, a rust inhibitor, a preservative, an antifungal agent, an antioxidant, an anti-reduction agent, and an evaporation accelerator as necessary. Various additives may be contained.

  Next, the ink used in this embodiment will be described more specifically. The present invention is not limited by the following examples as long as the gist thereof is not exceeded. In the text, “parts” and “%” are based on mass unless otherwise specified.

[Preparation of pigment dispersion]
For example, a pigment dispersion is prepared by the following procedure. In the following description, the dispersant is an aqueous solution obtained by neutralizing a styrene-acrylic acid copolymer having an acid value of 200 and a weight average molecular weight of 10,000 with a 10% by mass aqueous sodium hydroxide solution. That is.

<C. I. Preparation of Pigment Dispersion Containing Pigment Red 122>
10 parts of a pigment (CI Pigment Red 122), 20 parts of a dispersant, and 70 parts of ion-exchanged water are mixed and dispersed for 3 hours using a batch type vertical sand mill. Thereafter, coarse particles were removed by centrifugation. Furthermore, pressure filtration is performed with a cellulose acetate filter having a pore size of 3.0 μm (manufactured by Advantech) to obtain a pigment dispersion 1 having a pigment concentration of 10% by mass.

<C. I. Preparation of Pigment Dispersion Containing Pigment Blue 15: 3>
10 parts of a pigment (CI Pigment Blue 15: 3), 20 parts of a dispersant, and 70 parts of ion-exchanged water are mixed and dispersed for 5 hours using a batch type vertical sand mill. Thereafter, coarse particles were removed by centrifugation. Furthermore, pressure filtration is performed with a cellulose acetate filter (manufactured by Advantech) having a pore size of 3.0 μm to obtain a pigment dispersion 2 having a pigment concentration of 10% by mass.

<C. I. Preparation of Pigment Dispersion Containing Pigment Yellow 74>
10 parts of a pigment (CI Pigment Yellow 74), 20 parts of a dispersant, and 70 parts of ion-exchanged water are mixed and dispersed for 1 hour using a batch type vertical sand mill. Thereafter, coarse particles were removed by centrifugation. Further, pressure filtration is performed with a cellulose acetate filter having a pore size of 3.0 μm (manufactured by Advantech) to obtain a pigment dispersion 3 having a pigment concentration of 10% by mass.

<C. I. Preparation of Pigment Dispersion Containing Pigment Black 7>
10 parts of carbon black pigment (CI Pigment Black 7), 20 parts of a dispersant, and 70 parts of ion-exchanged water are mixed and dispersed for 3 hours using a batch type vertical sand mill. In addition, the peripheral speed at the time of dispersion was set to double that when the pigment dispersion liquid 1 was prepared. Thereafter, coarse particles are removed by centrifugation. Further, pressure filtration is performed with a cellulose acetate filter having a pore size of 3.0 μm (manufactured by Advantech) to obtain a pigment dispersion 4 having a pigment concentration of 10% by mass.

<C. I. Preparation of Pigment Dispersion Containing Pigment Red 149>
10 parts of a pigment (CI Pigment Red 149), 20 parts of a dispersant, and 70 parts of ion-exchanged water are mixed and dispersed for 3 hours using a batch type vertical sand mill. Thereafter, coarse particles were removed by centrifugation. Furthermore, pressure filtration is performed with a cellulose acetate filter having a pore size of 3.0 μm (manufactured by Advantech) to obtain a pigment dispersion 1 having a pigment concentration of 10% by mass.

<C. I. Preparation of Pigment Dispersion Containing Pigment Green 7>
10 parts of a pigment (CI Pigment Green 7), 20 parts of a dispersant, and 70 parts of ion-exchanged water are mixed and dispersed for 3 hours using a batch type vertical sand mill. Thereafter, coarse particles were removed by centrifugation. Furthermore, pressure filtration is performed with a cellulose acetate filter having a pore size of 3.0 μm (manufactured by Advantech) to obtain a pigment dispersion 1 having a pigment concentration of 10% by mass.

(Preparation of ink)
The components described above are mixed and sufficiently stirred, and then pressure filtration is performed with a cellulose acetate filter having a pore size of 0.8 μm (manufactured by Advantech). By carrying out the above preparation, in this example, cyan (C), magenta (M), yellow (Y), black (K), light cyan (LC), light magenta (LM), red (R) , 9 colors of gray (Gray) and light gray (LGray) are obtained.

  Next, the image quality improving liquid used in this embodiment will be described.

<Adjustment of image quality improving liquid>
A styrene (St) -acrylic acid (AA) copolymer A (St / AA = 70/30 (mass%), molecular weight: 10500, measured acid value: 203) synthesized by a solution polymerization method using a radical initiator. A liquid composition A having the following composition is used. In addition, potassium hydroxide is used as the basic substance, and the addition amount is adjusted so that the pH of the liquid composition becomes 8.0.
・ Styrene-acrylic acid copolymer A 2 parts ・ Glycerin 7 parts ・ Diethylene glycol 5 parts ・ Water 86 parts

  The image quality improving liquid obtained by the above adjustment is a liquid for controlling at least glossiness, but the image quality improving liquid is not limited by the above components. The image quality improving liquid of the present invention may have a property of improving glossiness by containing, for example, the above components, but improves image quality by imparting bronze suppression, water resistance, light resistance, etc. Any colorless and transparent ink can be used.

(Image processing)
Next, an image processing process using the ink in the present embodiment will be described.

  FIG. 4 is a block diagram for explaining a process of image data conversion processing according to the present embodiment. The image processing steps performed in this embodiment are shared by the host device 110 and the recording device (printer) 210.

  The host device 110 is, for example, a personal computer (PC), and the process relating to the image processing of this embodiment is executed by the application J0001 and the printer driver PD11 for the recording device used in this embodiment.

  The application J0001 is a process for creating image data to be passed to a printer driver PD11, which will be described later, and a process for setting recording control information for controlling printing, based on information specified by the user on the UI screen on the monitor of the host device 110. Execute.

  FIG. 5 is a diagram showing a configuration example of such image data information and recording control information. The recording control information includes “recording medium information”, “recording quality information”, and “other control information” such as a paper feed method. The recording medium information describes the type of recording medium to be recorded, and specifies any one type of recording medium among plain paper, glossy paper, coated paper, postcard, and printable disc. . The recording quality information describes the quality of the recording, and any one of “clean”, “standard”, “fast”, etc. is defined. These image data and recording control information processed by the application are transferred to the printer driver PD at the time of recording.

  Referring again to FIG. 4, the printer driver PD includes a pre-stage process J0002, a post-stage process J0003, a γ correction J0004, a quantization unit J0005, and a print data creation J0006. Below, each process is demonstrated easily.

  The pre-stage process J0002 performs color gamut mapping. This process performs data conversion for mapping the color gamut reproduced by the image data (R, G, B) of the sRGB standard into the color gamut reproduced by the printer. Specifically, by using a three-dimensional LUT (look-up table) for 256-gradation data in which each of R, G, and B is represented by 8 bits, R ′ of 8 bits each having a different color gamut. , G ′ and B ′ data.

  The post-process J0003 is an 8-bit color that is a combination of R, G, and B data to which the color gamut is mapped based on the post-process 3D LUT, and a combination of inks that reproduce the color represented by the data. Convert to decomposed data. Specifically, data of 256 gradations in which each of R′G′B ′ is expressed by 8 bits is converted into C, M, Y, K, Lc by using a three-dimensional LUT (look-up table). , Lm, R, G, Gray. In the latter stage processing J0003 of the present embodiment, 8-bit color separation data CL of the image quality improving liquid for reproducing the desired glossiness in the combination of the inks is also generated.

  The γ correction J0004 converts the density value (gradation value) of the color separation data of each color obtained by the post-processing J0003. Specifically, conversion is performed using a one-dimensional LUT so that the color separation data is linearly associated with the gradation characteristics of the printer.

  The quantization unit J0005 performs quantization processing for converting each 8-bit color separation data for each color subjected to γ correction into 5-bit data. In this embodiment, 256-bit 8-bit data is converted to 17-gradation 5-bit data using an error diffusion method. The 5-bit recorded image data is data serving as an index for indicating a dot arrangement pattern in a dot arrangement patterning process described later. The data quantized to 17 gradations for each color is gradation value information indicating any gradation of levels 0 to 16.

  The print data creation process J0006 combines the above-described recording control information and the 5-bit image data created by the quantization unit J0005, and completes the print data to be transferred to the recording device 210. The print data generated as described above is supplied to the recording device 210.

  When the printing apparatus 210 receives print data from the host apparatus 110, the printing apparatus 210 performs a dot arrangement patterning process J0007 and a mask process J0008 on the 5-bit image data of each color included in the print data.

  In the dot arrangement patterning process J0007, the input 17-value gradation value information is converted into a dot arrangement pattern and binarization processing is performed. Thereby, binary data (2 bits) indicating whether or not ink is ejected to each pixel corresponding to the resolution that can be recorded by the recording apparatus can be obtained.

  FIG. 6 is a diagram for explaining a dot arrangement pattern of 17 gradations used in this embodiment. In the dot arrangement patterning process J0007, for example, 17-value gradation data (level 0 to level 16) represented by 300 dpi is converted into binary data represented by 1200 dpi. One pixel of 300 dpi corresponds to 4 × 4 pixels of 1200 dpi, and 17-value gradation data of 300 dpi is converted into a combination of recording (1) and non-recording (0) of each pixel of 1200 dpi. In the figure, a pixel (1200 dpi) indicating a black circle indicates a pixel (1) where dots are recorded, and a blank pixel indicates a pixel (0) where dots are not recorded.

  In the subsequent mask processing J0008, by using a plurality of mask patterns that are complementary to each other, recording on the pixels for which dot recording has been determined by the dot arrangement patterning processing J0007 is distributed to a plurality of recording scans. By the mask processing, binary data of each color of C, M, Y, K, Lc, Lm, R, Gray, LGray, and CL is converted into a plurality of binary data corresponding to the number of multipaths. This mask process will be described in detail later.

  The binary data after the mask processing is supplied to the head drive circuit J0009 at an appropriate timing, converted into drive pulses for the recording head 1, and then ink is ejected from the recording head 1 of each color at a predetermined timing.

  Hereinafter, general multi-pass recording will be described. Multi-pass printing is a printing method in which image data contained in a unit area of a printing medium is printed by a plurality of printing scans of a printing head.

  FIG. 7 is a diagram for schematically explaining multi-pass printing. The recording head 1 used in this embodiment actually has 768 nozzles, but for the sake of simplicity, the recording head P0001 having 16 nozzles is used here to complete an image in four recording scans. The 4-pass multi-pass recording will be described. In this case, the 16 nozzles can be divided into first to fourth nozzle groups each including four nozzles.

  Mask patterns P0002 (a to d) indicate mask patterns respectively addressed to the first to fourth nozzle groups. A black-painted area is a print-allowed pixel that allows dot recording, and a white-painted area is a dot. The recording non-permitted pixels that do not allow the recording are respectively shown. The print data to be printed by each nozzle is subjected to a logical product operation with the mask pattern every print scan, and ink is ejected only to the pixels that are allowed to be printed in each print scan. The mask patterns P0002 (a) to P0002 (d) are complementary to each other, and when these four mask patterns are overlapped, recording of an area corresponding to 4 × 4 pixels = 16 pixels is completed. Yes.

  Each pattern indicated by P0003 to P0006 shows a state in which an image is completed by overlapping recording scans. When each recording scan is completed, the recording medium is conveyed by the width of the nozzle group in the direction of the arrow in the figure (by four nozzles in this figure). By repeating such a transport operation and a recording scan according to the mask pattern, an image is completed by four times of the recording scan in the unit area (area corresponding to the width of each nozzle group) of the recording medium.

  In FIG. 7, in any of the mask patterns of P0002 (a) to (d), 4 pixels out of 16 × 16 pixels are recording allowable pixels. As described above, the ratio of the pixels that can be recorded by the mask pattern among the pixels that can be recorded by one scan of each nozzle group is defined as a print allowance rate (%) in this specification. That is, in the case of FIG. 7, the recording allowance of each nozzle group is 25%.

(Glossiness and image clarity evaluation method)
In the present specification, the improvement in gloss refers to bringing the gloss level described later or the value of image clarity close to a desired value. Hereinafter, the glossiness and image clarity of the surface of the recording medium, which is a reference for evaluating the gloss uniformity within the image in this embodiment, will be described. In general, an index for evaluating the glossiness of a recording medium or an image includes glossiness and image clarity, and image clarity is determined by the glossiness and haze.

  FIGS. 8A to 8D are diagrams illustrating a method for measuring glossiness and haze. FIG. 8A shows a state in which the reflected light of light that has entered the mirror surface with less unevenness at an incident angle of 20 ° is detected. A detector (for example, B-4632 (Japanese name; Micro-Haze Plus) manufactured by BYK-Gardner) is arranged so that the center of the receiving unit coincides with the specular reflection position of 20 ° with respect to the mirror surface. The intensity distribution of reflected light is measured with a predetermined aperture width. FIG. 8D is a diagram showing the intensity distribution of the reflected light detected in this way by the detector. In general, reflected light includes specularly reflected light and irregularly reflected light distributed around it. The specularly reflected light traveling at a reflection angle of 20 ° is detected with an aperture width of 1.8 ° at the center of the detector, The irregularly reflected light located outside is detected with an aperture width that further extends the range to ± 2.7 °. From such a detection result, the glossiness is obtained as a reflectance of regular reflection light (intensity within an aperture width of 1.8 °) with respect to incident light. Further, the haze is obtained as a reflectance at an opening width in which the range is expanded to ± 2.7 ° outside the opening width 1.8 °. In this example, the glossiness is measured according to JIS standard K5600, and the haze is measured according to ISO standard DIS13803.

  The image clarity is determined by the image clarity = (glossiness−haze) / (glossiness + haze) based on the measured glossiness and haze, and represents the clarity of the image on the recording medium. As shown in FIG. 8A, a smooth mirror surface with few irregularities has a high ratio of gloss to haze, that is, high image clarity and a clear image. On the other hand, on the surface with many irregularities as shown in FIGS. 8B and 8C, the ratio of gloss to haze is low, that is, the image clarity is low, and the image reflected on the recording medium is blurred. The units of glossiness, haze, and image clarity obtained by the detector are dimensionless, and any of them can take a value between 0 and 1.

(Relationship between glossiness and image clarity)
When an image is recorded on a recording medium using colored ink, the state of unevenness on the surface of the recording medium varies depending on the amount of colored ink. That is, the glossiness and image clarity of the recorded image surface vary depending on the gradation of the image.

  FIG. 9 is a diagram for explaining how the image clarity and glossiness change according to the gradation, that is, the amount of colored ink. In this embodiment, the image clarity and glossiness to be targeted are set in advance. In FIG. 9, “low” is obtained when a measurement result lower than this target value is obtained, and “high” is obtained when a high measurement result is obtained. “Medium” is indicated when a measurement result of about “high” and the target value is obtained.

  In the low density portion, since there are many blank areas and the paper surface is exposed, the amount of regular reflection is small and the glossiness is low. However, since the haze is small, the image clarity is high. In the middle density portion, the colored ink covers the paper surface almost uniformly, so that the amount of regular reflection increases without increasing haze. As a result, glossiness and image clarity are high. Furthermore, in the high density portion, many colored inks cover the paper surface while overlapping each other, so that the amount of regular reflection is large but the haze is also high. Therefore, the glossiness is high, but the image clarity is lower than that in the middle density portion.

  As described above, the glossiness and the image clarity vary depending on the gradation of the image, and the present invention has a problem that a region with high glossiness and image clarity and a region with low glossiness are mixed in the same image. In other words, the present invention is not intended to obtain an image with high glossiness or image clarity, and aims to converge both image clarity and glossiness to about “medium” at any gradation. Therefore, in the following embodiments, a transparent image quality improving liquid is used as a means for adjusting both glossiness and image clarity to about “medium”.

  FIGS. 10A to 10C are diagrams for explaining how the recording of the colored ink and the image quality improving liquid or the recording order affects the smoothness of the surface of the recording medium. FIG. 10A shows a recording state when only colored ink is recorded and no image quality improving liquid is recorded. In this case, the glossiness and image clarity vary depending on the gradation as shown in FIG.

  FIG. 10B shows a recording state when recording is performed without making the recording order of the colored ink and the image quality improving liquid constant. In general, when the image quality improving liquid is applied directly to the recording medium and when the image quality improving liquid is applied after the colored ink layer is formed, the permeation state of the image quality improving liquid is different, and the recording medium is recorded after recording. The thickness of the layer formed on it is different. Therefore, when recording is performed without making the recording order of the colored ink and the image quality improving liquid constant, the location where the image quality improving liquid is applied after the colored ink, and the location where the colored ink is applied after the image quality improving liquid And the unevenness as shown in FIG. 10B appears. Such unevenness becomes more prominent in a high gradation region where a large amount of ink is applied. Hereinafter, such a method of recording while recording the colored ink and then recording the image quality improving liquid and recording the colored ink after recording the image quality improving liquid is referred to as mixed printing.

  When mixed printing is performed, in the low density portion, the exposed area of the blank paper is reduced by the amount of the image quality improving liquid added, and the amount of specular reflection, that is, the glossiness is increased. On the other hand, the haze increases due to the unevenness, so that the image clarity is lowered. Therefore, when the mixed printing is performed on the low density portion, the glossiness and image clarity that were “low” and “high” can both be set to “medium” (operation a).

  When mixed printing is performed in the middle density portion, the unevenness increases as shown in FIG. 10B, and both glossiness and image clarity decrease compared to the case of FIG. To do. Therefore, the glossiness and image clarity that were both “high” can be set to about “medium” (action b). Further, when mixed printing is performed at a high density portion, the unevenness becomes larger and the glossiness and image clarity are both further reduced.

  On the other hand, FIG. 10C shows a recording state when the image quality improving liquid is recorded after recording the colored ink. When the image quality improving liquid is recorded after recording the colored ink, a layer having a uniform thickness is formed on the colored ink layer fixed to some extent, so that the surface of the recording medium is shown in FIG. As shown in c), the surface becomes almost smooth, and unevenness as in mixed recording is not formed. Hereinafter, a method of recording while keeping the order of recording the image quality improving liquid after recording such colored ink is referred to as post-printing recording in this specification. In such post-recording, since the smooth layer area increases as the density increases, the regular reflection amount can be adjusted without changing the haze.

  In this case, in the low density portion, the blank exposed area decreases by the amount of the image quality improving liquid added, and the glossiness increases. However, since the haze remains low, the image clarity also remains high. In the medium density portion, the glossiness is high by recording only the color ink, and when the image quality improving liquid is post-printed here, the layer of the image quality improving liquid acts to reduce the glossiness. However, since the unevenness as shown in FIG. 10B is not formed, the degree of decrease in glossiness is small compared to mixed printing, and the image clarity is not lowered. That is, even if post-recording is performed on the low and medium density portion, both glossiness and image clarity cannot be made “medium”.

  On the other hand, in the high density portion, the layer formed by post-printing recording of the image quality improving liquid acts to reduce the glossiness to an appropriate amount and does not change the image clarity that is originally “medium”. Therefore, when post-recording is performed on the high density portion, both glossiness and image clarity can be set to “medium” (operation c).

  Based on the above situation, in the present embodiment, mixed recording is performed to obtain the actions a and b for the low density part and the medium density part, and the action c is obtained for the high density part. Make a hitting record. As a result, the glossiness and the image clarity in the entire density region are both adjusted to “medium”.

  FIG. 11 is a diagram illustrating an arrangement state of the ejection port arrays when the recording head 1 used in this embodiment is observed from the ejection port surface. The recording head 1 of the present embodiment is configured by arranging a recording element substrate 1 in which five ejection rows are arranged in parallel and a recording element substrate 2 in which six ejection port rows are arranged in parallel as shown in the figure. Yes. The nozzle row N1 and the nozzle row N11 located on both sides in the main scanning direction are nozzle rows that discharge image quality improving liquid. The nozzle rows N2 to N10 arranged between these two nozzle rows are nozzle rows that eject the above-described nine colored inks.

  In this embodiment, an image is recorded on a recording medium while moving the recording head 1 reciprocally in the main scanning direction. At this time, by the ejection control of the nozzle rows N1 and N11 that discharge the image quality improving liquid, the image quality improving liquid is recorded before the colored ink, or the image quality improving liquid is recorded after the colored ink. You can switch the strike record. In order to realize such switching, a mask pattern is used in this embodiment. Specifically, in order to switch between mixed printing and post printing according to each density area (recording duty), a mask pattern used for each printing scan for that pixel according to the gradation level of each pixel of 300 dpi. Select.

  FIG. 12 is a flowchart for explaining mask pattern selection processing executed by the controller 100 in this embodiment. This process is executed by the mask process J0008 shown in FIG.

  When this process is started, the controller 100 first receives binary image data output by the dot arrangement patterning process J0007 for each 300 dpi pixel (step S1). The binary data received here corresponds to one of level 0 to level 16 shown in FIG. 6 that is composed of 1200 dpi 4 × 4 pixels for each 300 dpi pixel.

  In subsequent step S2, the controller 100 calculates the total recording duty for the pixel, that is, the predetermined area, from the level information of each color of the image data. Here, the recording duty of a certain ink color indicates a ratio of pixels in which the ink color is determined to be recording (1) out of each pixel of 1200 dpi 4 × 4 pixels. Specifically, the recording duty of level 0 pixels is 0%, the recording duty of level 8 is 50%, and the recording duty of level 16 is 100%. The total recording duty corresponds to the sum of recording duties for all ink colors.

  In subsequent step S3, controller 100 selects a mask pattern corresponding to the total recording duty obtained in step S2. The mask pattern selected at this time is a mask pattern that satisfies the table shown in FIG. That is, in the low density portion corresponding to the total recording duty of 0% to 15% and the middle density portion corresponding to the total recording duty of 15% to 50%, a mask pattern capable of realizing mixed printing is selected. In step S4, a mask pattern A is set. In the high density portion corresponding to the total recording duty of 50% or more, a mask pattern that realizes post-printing is selected, and the mask pattern B is set in step S5.

  FIGS. 14A to 14C are diagrams for explaining the mask pattern B that realizes post-printing recording, which is set in step S5 when performing one-pass bidirectional recording. FIG. 14A shows a mask pattern used in the forward direction, and FIG. 14B shows a mask pattern used in the return direction. In FIG. 7, the description has been given using the mask pattern in units of 4 × 4 pixel areas, but here, for the sake of simplicity, the mask in units of areas having 4 pixels in the main scanning direction and 1 pixel in the sub-scanning direction is used here. Use a pattern. In each figure, M1 is a mask pattern used by the nozzle row N1 that discharges image quality improving liquid, M2 is a mask pattern that is used by the discharge port rows N2 to M10 that discharge colored ink, and M3 is a nozzle row that discharges the image quality improving liquid. The mask pattern used by N11 is shown.

  In 1-pass printing, data thinning processing as shown in FIG. 7 is not performed for colored ink. Therefore, the print allowable rate of the mask pattern M2 to be used is 100% in both the forward scan and the backward scan. In the drawing, pixels shown in black indicate pixels that allow recording. On the other hand, with respect to the nozzle rows N1 and N11 that discharge the image quality improving liquid, the recording allowable rate in the scanning that records before the colored ink is 0%, and the recording allowable rate in the scanning that records after the colored ink. 100%. That is, in the forward scan FIG. 14A, the recording allowable rate of the mask pattern M3 of the nozzle array N11 that is recorded before the colored ink is 0%, and the mask pattern M1 of the nozzle array N1 that is recorded after the colored ink. The recording allowable rate is 100%. In FIG. 14B, the print allowance of the mask pattern M1 of the nozzle row N1 that is printed before the colored ink is 0%, and the mask pattern M3 of the nozzle row N11 that is printed after the colored ink. The recording allowable rate is 100%. As a result, on the recording medium, as shown in FIG. 14C, in any pixel, the color ink is recorded and the image quality improving liquid is recorded. That is, by using the mask pattern B shown in FIGS. 14A and 14B, post-printing recording can be realized.

  On the other hand, FIGS. 15A to 15C are diagrams for explaining the mask pattern A that realizes mixed printing, which is set in step S4 when performing one-pass bidirectional recording. . Even in mixed printing, in the mask pattern M2 for colored ink, the printing allowable rate in the backward scanning is 100% even in the forward scanning. On the other hand, with respect to the nozzle rows N1 and N11 that discharge the image quality improving liquid, the masks M1 and M3 having a recording allowance of 50% that are complementary to each other are used in both the forward scanning and the backward scanning. . That is, in both the forward scan shown in FIG. 15A and the backward scan shown in FIG. 15B, the print allowance of the mask pattern M1 used by the nozzle row N1 and the mask pattern M3 used by the nozzle row N11 is 50%. Yes, these M1 and M3 are complementary to each other. Then, on the recording medium recorded using such a mask pattern, as shown in FIG. 15 (c), the pixels on which the color-quality ink is recorded and the image quality improving liquid is recorded, and the image quality improving liquid A pixel in which colored ink is recorded on the recording is mixed. That is, by using the mask pattern A shown in FIGS. 15A and 15B, mixed printing can be realized by one-pass bidirectional recording.

  Again, it returns to the flowchart of FIG. When the mask pattern A or B is set in step S4 or step S5, the controller 100 performs a logical product with the set mask pattern for the binary data received in step S1 in step S6. Then, print data (ejection data) for each of the nozzle arrays N1 to 11 in each scan is generated and output to the head drive circuit J0009. This process is completed.

  After the above processing is performed, the recording data input to the head drive circuit J0009 is ejected by the ejection port arrays of the individual nozzle arrays N1 to N11. As a result, the color ink and the image quality improving liquid are applied to the recording medium by a recording method corresponding to the total recording duty of each pixel, and an image in which both glossiness and image clarity in all density regions are adjusted to about “medium” is obtained. I can do it.

  The above has described a method of switching between mixed printing and one-shot printing in one-pass bidirectional using a mask pattern, but the above method can also be applied to bidirectional multi-pass printing of two or more passes.

  FIGS. 16A and 16B are diagrams for explaining a mask pattern B that realizes post-printing recording set in step S5 when two-pass bidirectional is executed. FIG. 16A shows a mask pattern (upper stage) used in forward scanning and a mask pattern (lower stage) used in backward scanning, nozzle arrays N1 and N2 for ejecting image quality improving liquid, and nozzle arrays N2 for ejecting colored ink. 10 is shown. For the nozzle arrays N2 to 10 that discharge colored ink, a mask pattern M2 having a recording allowance of 50% is prepared in order to perform two-pass multi-pass printing. In the mask pattern M2, the mask pattern used in the forward scanning (upper stage) and the mask pattern used in the backward scanning (lower stage) have a complementary relationship. For the nozzle rows N1 and N11 that discharge the image quality improving liquid, the recording allowance in the scan that records before the colored ink is 0%, and the record allowance in the scan that records after the colored ink is 50%. .

  Specifically, in the forward scan, the recording allowance of the mask pattern M3 of the nozzle array N11 that is recorded before the colored ink is 0%, and the recording of the mask pattern M1 of the nozzle array N1 that is recorded after the colored ink is performed. The allowable rate is 50%. At this time, the forward scanning mask patterns M1 and M2 are equal, and the image quality improving liquid is recorded after the colored ink in the same scanning only for the pixels on which the colored ink is recorded. In the backward scan, the recording allowance of the mask pattern M1 of the nozzle array N1 that is recorded before the colored ink is 0%, and the recording allowance of the mask pattern M3 of the nozzle array N11 that is recorded after the colored ink is 0%. It is 50%. In the backward scan, the mask patterns M2 and M3 are the same, and the image quality improving liquid is recorded after the colored ink in the same scan only for the pixels on which the colored ink is recorded. As a result, on the recording medium, as shown in FIG. 16B, in any pixel, the color ink is recorded and the image quality improving liquid is recorded.

  On the other hand, FIGS. 17A and 17B are diagrams for explaining the mask pattern A that realizes mixed printing set in step S5 in the same way as FIG. 16 when performing two-pass bidirectional. is there. Even in mixed printing, for the nozzle arrays N2 to 10 that discharge colored ink, since two-pass multipass printing is performed, a mask pattern M2 having a printing allowance of 50% is prepared, which is the same as FIG. . On the other hand, with respect to the nozzle rows N1 and N11 that discharge the image quality improving liquid, the recording allowance in the scanning that records before the colored ink is 25%, and the recording allowance in the scanning that records after the colored ink is 25%. The masks M1 and M3 are used. In both the masks M1 and M3, recording is permitted for half of the pixels that are permitted to be recorded in the mask pattern M2 of the colored ink. That is, of the pixels where the colored ink is recorded, half of the pixels are recorded with the image quality improving liquid before the colored ink, and the other half of the pixels are recorded with the image quality improving liquid after the colored ink. The above relationship is the same in the backward scanning. Then, on the recording medium recorded using such a mask pattern, as shown in FIG. 17 (b), the pixels on which the color-quality ink is recorded and the image quality improving liquid is recorded, and the image quality improving liquid A pixel in which colored ink is recorded on the recording is mixed. That is, by using the mask pattern A shown in FIG. 17A, mixed printing can be realized by two-pass bidirectional recording.

  As described above, in this embodiment, in both 1-pass bidirectional printing and 2-pass bidirectional printing, mixed printing is performed in association with the printing duty of each pixel at each printing scan. You can switch the post-recording. As a result, it is possible to record a uniform image in which glossiness and image clarity are not uneven in all density regions, with both glossiness and image clarity adjusted to about “medium”.

  In the above description, mixed color printing and post color printing are switched for all the color inks used. However, for example, when inks that cause problems of image clarity and glossiness are limited, FIG. A recording head as shown in FIG. In this case, the above-described control can be performed on the colored ink ejected from the nozzle rows N2 to N5 sandwiched between the nozzle rows N1 and N6 that eject the image quality improving liquid. On the other hand, the color ink ejected from the nozzle rows N7 to N11 is not a target of the control.

  In the example of the mask pattern described in FIGS. 14 to 17, a mask pattern having a completely complementary relationship is prepared for both the colored ink and the image quality improving liquid. However, the effects of the present invention and this embodiment are as follows. It is not limited to such a mask pattern. Even if the result of overlaying a plurality of mask patterns is larger than 100% or smaller than 100%, the effect of the above embodiment can be obtained as long as the rule of mixed printing and post-printing recording is maintained. .

[Example 2]
Also in this embodiment, the ink jet recording apparatus shown in FIGS. 1A and 1B and the recording head shown in FIG. 11 are used. Also in this embodiment, mask pattern selection processing is executed according to the flowchart shown in FIG. However, in this embodiment, not only the total recording duty for each pixel but also the number of ink colors recorded on that pixel (that is, whether it is a primary color, a secondary color, or a tertiary color or more) is mixed. Differentiate whether to make a strike record or a late strike record. This is because the image clarity tends to decrease as the number of ink colors recorded in the pixels increases.

  FIG. 18 is a diagram illustrating the setting of mixed printing or post printing for the combination of the total printing duty and the number of inks in this embodiment. For primary colors, mixed printing is performed with a recording duty of 0 to less than 75%, and post-printing is performed with 75% or more. In the secondary color, the image clarity is about “medium” from the lower gradation than in the case of the primary color, so mixed printing is performed with a recording duty of 0 to less than 50%, and post-printing recording is performed with 50% or more. Do. For tertiary colors and higher, the image clarity is “medium” from a lower gradation than for secondary colors, so mixed printing is performed with a recording duty of less than 15%, and post-printing recording is performed with 15% or more. Do.

  That is, the controller 100 according to the present embodiment, in step S3 of FIG. 12, determines whether the total recording duty obtained in step S2 and whether the recording on the target pixel is a primary color, a secondary color, or a tertiary color or more. Accordingly, the mask pattern A or the mask pattern B is selected.

  As described above, in this embodiment, mixed printing and post-printing printing are switched in association with the total printing duty of each pixel and the number of inks printed on the target pixel at each printing scan. As a result, it is possible to record a uniform image in which glossiness and image clarity are not uneven in all density areas of all color reproduction areas, with both glossiness and image clarity adjusted to about “medium”.

[Example 3]
Also in this embodiment, the ink jet recording apparatus shown in FIGS. 1A and 1B and the recording head shown in FIG. 11 are used. Also in this embodiment, mask pattern selection processing is executed according to the flowchart shown in FIG. However, in this embodiment, whether to perform mixed printing or post-printing recording is determined based on the combination of the recording duty of each ink color recorded on the pixel, not the total recording duty for each pixel. Such a method is effective when the tendency of image clarity and gloss differs depending on the ink color.

  FIG. 19 is a diagram illustrating a setting example of mixed printing or post printing for a combination of cyan printing duty and magenta printing duty in the present embodiment. In step S3 of FIG. 12, the controller 100 of the present embodiment changes the mask pattern A or the mask pattern B so as to satisfy the table shown in FIG. 19 from the combination of the recording duty of each ink color obtained in step S2. select. With such a configuration, even with the same total recording duty, mixed printing or post-printing recording can be made different according to the balance between cyan recording duty and magenta recording duty.

  Here, for the sake of simplicity of explanation, the description has been made on the content of setting whether to perform mixed printing or post-printing recording according to the recording duty of the two colors of cyan and magenta. The device is equipped with 9 colored inks. Accordingly, in practice, a configuration in which mixed printing or post-printing recording is set for all combinations of nine color inks is most preferable. However, particularly when there is a specific ink that affects the image clarity and the glossiness, either mixed printing or post printing may be set depending on the combination of the recording duties of these inks.

  As described above, in this embodiment, mixed printing and post printing are switched in accordance with the combination of the printing duty of each color of each pixel at each printing scan. As a result, it is possible to record a uniform image in which glossiness and image clarity are not uneven in all density areas of all color reproduction areas, with both glossiness and image clarity adjusted to about “medium”.

[Example 4]
Also in this embodiment, the ink jet recording apparatus shown in FIGS. 1A and 1B and the recording head shown in FIG. 11 are used. Also in this embodiment, mask pattern selection processing is executed according to the flowchart shown in FIG. In the third embodiment, whether to perform mixed printing or post-printing recording is determined depending on the combination of the recording duty of each ink color. However, in this embodiment, mixed printing is performed depending on the hue and brightness expressed by each pixel. Decide whether to record later or later. Such a method is effective when the tendency of image clarity and gloss varies depending on the hue and brightness.

FIG. 20A is a diagram showing the arrangement relationship of hues in the color space. As described above, all hues can be classified into 12 hues according to the basic three colors (cyan, magenta, yellow) and their balance. In this embodiment, the hue (a ^* b ^* ) and lightness L ^* of each pixel can be determined from the combination of the recording duty of each ink color obtained in step S2 of FIG. Therefore, the controller 100 determines which hue shown in FIG. 20 is included in the hue of each pixel from the combination of the print duties of each ink color obtained in step S2. Then, the lightness L ^{* of} each pixel is compared with a threshold value TL ^* determined for each hue shown in FIG. Generally, the total recording duty increases as the lightness decreases. Therefore, if the lightness of the pixel is higher than the threshold value, the mask pattern A is selected. If the lightness is lower than the threshold value, the mask pattern B is selected. You can switch between recording and post-recording.

  As described above, in this embodiment, mixed printing and post printing are switched in accordance with the hue and brightness of each color of each pixel at each printing scan. As a result, it is possible to record a uniform image in which glossiness and image clarity are not uneven in all density areas of all color reproduction areas, with both glossiness and image clarity adjusted to about “medium”.

  In the above description, the example in which the hue is divided into 12 types as shown in FIG. 20A has been described. However, the effect of the present embodiment can be achieved even when classified into more types or fewer types. It can be demonstrated.

[Example 5]
Also in this embodiment, the ink jet recording apparatus shown in FIGS. 1A and 1B and the recording head shown in FIG. 11 are used. However, in this embodiment, the mask pattern is selected based on the RGB data before color conversion, not the binary data received from the dot arrangement patterning process J0007.

  FIG. 21 is a block diagram for explaining a process of image data conversion processing according to the present embodiment. Compared with FIG. 4, in this embodiment, mask selection information MD for designating a mask to be selected is generated in a post-mask selection process J0003 that performs conversion processing from RGB data to multi-value data for colored ink. . The mask selection information MD is transmitted from the host apparatus 110 to the recording apparatus 210, and the mask pattern specified by the mask selection information MD is used in the mask process J0008.

  FIGS. 22A to 22C are diagrams illustrating a method for generating mask selection information from input RGB data in the latter-stage / mask selection processing J0003 of the present embodiment. FIG. 22A shows a color space composed of RGB data input to the color conversion process, and each color data can take a value of 0-255. (R, G, B) = (0, 0, 0) is the lowest brightness black (K), (R, G, B) = (255, 255, 255) is the highest brightness white (W). Show. In the color conversion process, the signal values of nine colored inks (C, M, Y, K, Lc, Lm, R, Gray, and LGray) used for recording from the combination of (R, G, and B) are uniquely determined. A fixed three-dimensional lookup table is prepared.

  FIG. 22B is a diagram showing, in the color space, a region in which the mask pattern A is designated for performing mixed printing and a region in which the mask pattern B is designated for performing post printing. is there. The mask pattern B is designated for post-printing recording in an area where the brightness is low and the total recording duty is high, and this area is indicated by hatching in the drawing. For the remaining white area, the mask pattern A is designated in order to perform mixed printing. That is, the host device 110 generates mask selection information MD for setting the mask pattern A or the mask pattern B from the RGB data of each pixel, and transmits this to the recording device 210.

  The controller 100 of the recording apparatus 210 performs a logical product operation on the binary data obtained from the dot arrangement patterning process J0007 and a mask pattern (that is, mask pattern A or mask pattern B) according to the mask selection information MD. To generate ejection data.

  Thus, in this embodiment, mixed printing and post printing are switched in association with the RGB data of each pixel for each printing scan. As a result, it is possible to record a uniform image in which glossiness and image clarity are not uneven in all density areas of all color reproduction areas, with both glossiness and image clarity adjusted to about “medium”.

  In the color space, the distinction between the area designating the mask pattern A and the area designating the mask pattern B is not limited to the state shown in FIG. Glossiness and image clarity are also affected by the type of ink color. In particular, areas with low lightness (close to K) may be expressed only with black ink without mixing a large amount of ink. Post-printing recording is not always suitable in a low brightness area. In such a case, the area for designating the mask pattern A and the area for designating the mask pattern B may be distinguished, for example, as shown in FIG. In any case, the effect of this embodiment can be obtained as long as the mask pattern to be used is designated from the RGB data.

[Example 6]
In the above embodiment, mixed printing and post printing are switched by using a characteristic mask pattern. However, in this embodiment, mixed printing is performed by using the position of the nozzle row in the recording head to be used. Switch between recording and post-recording.

  FIG. 23 shows an example of the recording head 1 used in this embodiment. Here, for the sake of simplicity, the colored ink has four colors of C, M, Y, and K, and these are ejected by the nozzle rows N2 to N5. On the other hand, N1 is a nozzle row that discharges image quality improving liquid. In this embodiment, there is only one nozzle row that ejects the image quality improving liquid, but this nozzle row N1 has about twice as many ejection openings as the nozzle rows N2 to N5 that eject colored ink, and is in the sub-scanning direction. The nozzle array is very long. In the present embodiment, in such a nozzle row N1, nozzles in a region located at the same position in the sub-scanning direction as N2 to N5 are used for mixed printing. Then, the remaining nozzle rows, that is, the nozzle rows that lie in the sub-scanning direction from N2 to N5 are used for post-printing recording.

  FIGS. 24A to 24D show masks that can be applied to this embodiment when the recording head shown in FIG. 23 is used to perform multi-pass printing of two passes with colored ink and four passes with an image quality improving liquid. It is a figure which shows the example of a pattern. FIG. 24A shows a mask pattern A for realizing mixed printing, and FIG. 24C shows a mask pattern B for realizing post printing.

  In the mixed printing shown in FIG. 24A, the colored ink performs 50% printing in one pass and two passes. Therefore, for the nozzle arrays N2 to N5, a mask pattern M2 having a print allowance rate of 50% in each pass is prepared. On the other hand, the nozzle row N1 that discharges the image quality improving liquid performs recording with the nozzles at the same positions as the nozzle rows N2 to N5 in the sub-scanning direction, and does not perform recording with the nozzles at the protruding positions. That is, for the nozzle array N1, a mask pattern M1 is prepared in which the printing allowance for 1 pass and 2 passes is 50% and the printing allowance for 3 passes and 4 passes is 0%. In both M1 and M2, the mask pattern for one pass and the mask pattern for two passes have a complementary relationship. When four-pass bidirectional recording is performed using such a mask pattern (color ink is two-pass bidirectional recording), an image quality improving liquid is applied on the color ink on the recording medium as shown in FIG. A recorded portion and a portion where colored ink is recorded appear on the image quality improving liquid.

  On the other hand, in the case of post-printing recording shown in FIG. 24C, colored ink is equivalent to mixed printing. That is, a mask pattern M2 having a print allowance rate of 50% in each pass is prepared for the nozzle rows N2 to N5. On the other hand, the nozzle row N1 that discharges the image quality improving liquid performs recording with the nozzles located at positions protruding from the nozzle rows N2 to N5 in the sub-scanning direction, and does not perform recording with the nozzles located at the same position. That is, for the nozzle array N1, a mask pattern M1 is prepared in which the printing allowance for 1 pass and 2 passes is 0% and the printing allowance for 3 passes and 4 passes is 50%. In the mask pattern M1, the 3-pass mask pattern and the 4-pass mask pattern have a complementary relationship. When 4-pass bidirectional printing (2-pass bidirectional printing for colored ink) is performed using such a mask pattern, the image quality improving liquid is formed on the colored ink on the recording medium as shown in FIG. There are only places where is recorded.

  As described above, even in a configuration having only one nozzle row for discharging the image quality improving liquid, mixed printing and post-printing for each pixel can be performed by changing the recording allowance rate of each pass in multi-pass printing. Recording can be switched.

  For the mask pattern M1 shown in FIG. 24A described above, the recording allowance for 3 passes and 4 passes has been completely set to 0%. May not necessarily be such an allocation. In the mixed printing, it is sufficient that the portion where the image quality improving liquid is recorded on the colored ink and the portion where the colored ink is recorded on the image quality improving liquid are appropriately mixed. Therefore, even if the number of portions where the image quality improving liquid is recorded on the colored ink is increased by not setting the recording allowance rate to 0% in the 3-pass and 4-pass areas, the colored ink is recorded on the image quality improving liquid. If there is a place to be recorded, mixed recording can be realized.

  In the above description, as shown in FIG. 23, the nozzle row N1 that discharges the image quality improving liquid is described as being longer in the sub-scanning direction than the nozzle rows N2 to N5 that discharge the colored ink. However, even if these N1 to N5 have the same length, mixed printing and post-printing recording can be switched using the above-described mask pattern by shifting the positional relationship.

  FIG. 25 shows another example of the recording head that can be used in this embodiment. Here, the nozzle row N1 that discharges the image quality improving liquid has the same number of discharge ports as the nozzle rows N2 to N5 that discharge colored ink, but is shifted in the sub-scanning direction by a distance corresponding to half of the length. ing. In the present embodiment, nozzles located in an area overlapping with N2 to N5 in the sub-scanning direction among the nozzle row N1 are used for mixed printing. Then, the remaining nozzle row, that is, in the downstream region in the sub-scanning direction from N2 to N5, is used for post-printing. In the case of a recording head having such a configuration, by preparing mask patterns having different recording allowances for each region as described with reference to FIG. 24, mixed printing and post printing are performed in multi-pass printing of two or more passes. Can be adjusted according to the pixel.

  As described above, according to the present embodiment, mixed printing and post-printing recording can be switched by giving a characteristic to the arrangement of nozzle arrays that discharge colored ink and nozzle arrays that discharge image quality improving liquid. It becomes possible.

(Other)
In the above-described embodiments, the description has been made with the content of switching between mixed recording and post-recording on the premise that post-recording is effective for obtaining stable image clarity. However, such stable image clarity is realized in the same way even if the order is the reverse order (first recording) of recording colored ink after recording the image quality improving liquid. Sometimes you can. In this case, it is only necessary to prepare a mask pattern that can switch between mixed printing and first printing by a recording duty or the like. In any case, a recording method in which the application timing of the colored ink and the image quality improving liquid is separated and the order is kept constant to such an extent that each of the colored ink and the image quality improving liquid can be fixed independently. It suffices to have a configuration that enables switching between mixed recordings.

  In the above embodiment, as shown in FIG. 4 and FIG. 21, the processing up to quantization is executed by the host device, and the processing after the dot patterning processing is executed by the recording device. It is not limited to such a configuration. For example, a form in which a part of the processes J0002 to J0005 being executed in the host apparatus 110 is executed by the recording apparatus 210 may be executed, or all of the processes J0002 to J0005 are executed by the host apparatus 110. Alternatively, the processing J0002 to J0008 may be executed by the recording device 210.

DESCRIPTION OF SYMBOLS 1 Recording head 100 Controller 110 Host apparatus 210 Recording apparatus J0005 Quantization part J0007 Dot arrangement patterning process J0008 Mask process N1, N11 Nozzle row N2-N10 which discharges image quality improvement liquid Nozzle row which discharges colored ink M1 For image quality improvement liquid Mask pattern M2 Mask pattern for colored ink

Claims (12)

Using a recording head that discharges an image quality improving liquid that does not contain a color ink that contains a color material and an image recorded with the color ink and that improves the image quality of the image, and moves the recording head relative to the recording medium In an inkjet recording apparatus for recording an image on a recording medium,
An ink jet recording apparatus comprising: a recording control unit that changes the recording order of the colored ink and the image quality improving liquid for the predetermined area based on image data for the predetermined area of the recording medium.   The recording control means switches a mask pattern for determining whether recording is permitted or not permitted on a recording medium based on image data for the predetermined area, thereby changing a recording order of the colored ink and the image quality improving liquid for the predetermined area. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is made different.   The recording control means switches the nozzle used for ejection among the plurality of nozzles that eject the image quality improving liquid based on the image data for the predetermined area, thereby improving the color ink and the image quality improvement for the predetermined area. 2. The ink jet recording apparatus according to claim 1, wherein the recording order of the liquids is varied.   The inkjet recording apparatus according to claim 1, wherein an image is recorded on a recording medium by ejecting the colored ink and the image quality improving liquid while moving the head in a reciprocating manner with respect to the recording medium. In the recording head, two nozzle rows in which nozzles for discharging the image quality improving liquid are arranged in a direction intersecting the direction of movement, and directions in which the nozzles for discharging the colored ink intersect with the direction of movement A plurality of nozzle rows corresponding to a plurality of types of the colored inks arranged in
The two nozzle rows that discharge the image quality improving liquid are arranged on both sides of the plurality of nozzle rows that discharge the colored ink, and the image quality improving liquid is moved by the forward movement and the backward movement of the recording head. 5. The ink jet recording according to claim 4, wherein the recording order of the color ink and the image quality improving liquid in the predetermined area is changed by switching between the permissible and non-permissible recording in the two nozzle arrays to be ejected. apparatus.   The recording control means is configured to change the recording order of the color ink and the image quality improving liquid for the predetermined area based on a total recording duty of the colored ink corresponding to the predetermined area calculated from the image data. The inkjet recording apparatus according to claim 1, further comprising: means.   The recording control unit records the colored ink and the image quality improving liquid in the predetermined area based on a total recording duty of the colored ink corresponding to the predetermined area calculated from the image data and the number of the colored inks. 6. An ink jet recording apparatus according to claim 1, further comprising recording control means for changing the order.   The recording control unit determines a recording order of the colored ink and the image quality improving liquid for the predetermined area based on a combination of recording duties of the plurality of colored inks corresponding to the predetermined area calculated from the image data. 6. An ink jet recording apparatus according to claim 1, further comprising recording control means for making the difference.   The recording control means includes recording control means for changing the recording order of the colored ink and the image quality improving liquid for the predetermined area based on the hue and lightness in the predetermined area calculated from the image data. An ink jet recording apparatus according to any one of claims 1 to 5.   The recording control means includes recording control means for changing the recording order of the color ink and the image quality improving liquid for the predetermined area based on RGB data corresponding to the predetermined area obtained from the image data. An ink jet recording apparatus according to any one of claims 1 to 5.   The inkjet recording apparatus according to claim 1, wherein the colored ink contains a pigment as a coloring material. Using a recording head that discharges an image quality improving liquid that does not contain a color ink that contains a color material and an image recorded with the color ink and that improves the image quality of the image, and moves the recording head relative to the recording medium In an inkjet recording method for recording an image on a recording medium,
An ink jet recording method, wherein the recording order of the colored ink and the image quality improving liquid for the predetermined area is made different based on image data for the predetermined area of the recording medium.

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