JP2014166761A - Inkjet recording device and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording device capable of recording an image having high uniformity in both image clarity and glossiness regardless of a gradation of the image.SOLUTION: A recording head is able to discharge color ink, and an image quality improving liquid that changes at least one of glossiness and image clarity of an image. The recording head performs recording by performing multiple scans on an identical recording area of a recording medium, and applies the image quality improving liquid to the image. Control means is provided for controlling a ratio of the image quality improving liquid to be discharged to a unit area for each of the multiple scans. The control means selects a first mask or a second mask to be used for dividing recording data into multiple data sections corresponding to the multiple scans, according to a gradation value of the image expressed by input image data corresponding to the unit area. The input image data is expressed by RGB or Lab.

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method using a colored ink containing a color material and an image quality improving liquid, and more particularly to a technique for improving uneven gloss in an image.

  In recent inkjet recording, it is required to form high-quality images on various recording media. Coated paper is a recording medium suitable for high-quality image formation. Coated paper has an ink-receptive layer on a substrate such as high-quality paper or film. The type of coated paper has various textures ranging from glossy paper with a mirror surface with excellent gloss to matte matte paper. There is something to have.

  Among these coated papers, glossy paper has various requirements regarding the glossiness of the recorded image. For example, there is a demand for a uniform image with no uneven glossiness on the entire recording medium. In response to this requirement, Patent Document 1 discloses that in an inkjet recording apparatus that uses colored ink and an image quality improving liquid, gloss unevenness is reduced by adjusting the application amount of the image quality improving liquid according to the ink amount of the colored ink. A method is disclosed.

  In general, an area where the amount of colored ink applied on glossy paper is small has a lower glossiness described later than an area where the amount of applied ink is large. Therefore, in Patent Document 1, more image quality improving liquid is applied to a region with a small amount of ink applied than a region with a large amount of colored ink applied, and the glossiness of the region with a small amount of ink applied is increased. The uneven glossiness is reduced.

Japanese Patent No. 4003760

  However, as disclosed in Patent Document 1, there is a case where the uniformity of gloss in the same image cannot be sufficiently improved by the method of adjusting the amount of the image quality improving liquid applied and uniforming only the glossiness. . This is because the gloss in the image is affected not only by the uniformity of the glossiness but also by the uniformity of the image clarity, and the image clarity and the glossiness vary depending on the gradation of the recording portion.

  FIG. 1 is a diagram for explaining that image clarity and glossiness differ depending on gradation. In FIG. 1, “medium” indicates the target ranges of image clarity and glossiness. Further, “high” indicates a case where it is higher than the target range, and “low” indicates a case where it is low. As shown in FIG. 1, compared to the target range, the image quality is high and the glossiness is low in the highlight area, the image clarity and the glossiness are both high in the midtone, and the image quality is high in the shadow area (high density area). There is a tendency that glossiness is high at a degree. That is, there is a tendency that not only the glossiness but also the image clarity are different depending on the gradation, and if the uniformity of the image clarity is low even if the glossiness is uniformed, there is a problem that uneven glossiness is felt. In particular, the difference in glossiness and image clarity between the highlight portion and the shadow portion greatly affects the occurrence of uneven glossiness in the image.

  The present invention has been made paying attention to the above problems, and an ink jet recording apparatus capable of recording an image having high uniformity in both image clarity and glossiness, regardless of the gradation, and An object is to provide an ink jet recording method.

  In order to solve the above problems, the present invention has the following configuration.

That is, the first aspect of the present invention includes control means for controlling the amount of image quality improving liquid applied to the unit area in each of a plurality of scans, and the control means moves from the recording head to the unit area. The print data for discharging the image quality improving liquid is represented by a first mask and a second mask for dividing the print data into data corresponding to the plurality of scans, and input image data corresponding to the unit area. Selecting means for selecting use of the first mask and the second mask in accordance with a gradation value of an image to be obtained, wherein the second mask is relatively used in the plurality of scans. The recording rate of the recording data in the later scanning is determined to be higher than that of the first mask, and the selection means has a gradation value of an image represented by the input image data corresponding to the unit area. Predetermined floor If it is less than the value, the first mask is selected, while if the gradation value of the image represented by the input image data is greater than or equal to a predetermined gradation value, the second mask is selected. The input image data is image data represented by RGB or L ^* a ^* b ^* .

According to a second aspect of the present invention, there is provided at least one kind of colored ink containing a color material, and an image quality improving liquid that changes at least one of glossiness and image clarity of an image recorded on a recording medium by the colored ink. An ink jet recording method in which an image is recorded on the recording medium by scanning the recording head a plurality of times with respect to a unit area of the recording medium, and the image quality improving liquid is applied to the image. A control step of controlling the amount of image quality improving liquid applied to the unit area in each of a plurality of scans, wherein the control step is for discharging the image quality improving liquid from the recording head to the unit area. Of the first mask and the second mask for dividing the print data into data corresponding to the plurality of scans, the input image data corresponding to the unit area is used. A selection step of selecting use of the first mask and the second mask in accordance with the gradation value of the image to be represented, wherein the second mask is relatively in the plurality of scans. The recording rate of the recording data in the later scanning is determined to be higher than that of the first mask, and the selection step determines the gradation value of the image represented by the input image data corresponding to the unit area. When the gradation value is less than a predetermined gradation value, the first mask is selected. On the other hand, when the gradation value of the image represented by the input image data is greater than or equal to a predetermined gradation value, the second mask is selected. The input image data is image data represented by RGB or L ^* a ^* b ^* .

  According to the present invention, it is possible to record an image having high uniformity in both image clarity and glossiness regardless of the gradation of the recorded image, and an excellent gloss image can be obtained. become.

It is a figure which shows the relationship between the gradation of an image, image clarity, and glossiness. It is a figure for demonstrating glossiness and a haze. It is a figure which shows the difference in the state of the printing surface by the difference in the overlapping method of a colored ink and an image quality improvement liquid. 1 is a perspective view illustrating an appearance of an ink jet recording apparatus applied in the present embodiment. It is a perspective view which shows the inside of an inkjet recording device. It is a block diagram which shows the control structure of the inkjet recording device in this embodiment. It is a figure which shows the component which comprises the ink in this embodiment. It is a block diagram for demonstrating the flow of the conversion process of the image data of this embodiment. FIG. 4 is a diagram illustrating image data information and recording control information that a printer driver according to the present embodiment passes to a recording apparatus. It is a figure which shows the dot arrangement patterning process in this embodiment. It is a figure for demonstrating multipass printing and a mask pattern. It is a flowchart which shows the flow of the process which selects the mask pattern of an image quality improvement liquid in this embodiment. It is a figure for demonstrating the mask pattern in this embodiment. FIG. 6 is a diagram illustrating a relationship between an ink ejection amount and a mask pattern with respect to an image gradation in the present embodiment. It is a figure for demonstrating the mask pattern in 2nd Embodiment. FIG. 10 is a diagram illustrating a relationship between an ink ejection amount and a mask pattern with respect to an image gradation in the third embodiment. FIG. 10 is a diagram illustrating a relationship between an ink ejection amount and a mask pattern with respect to an image gradation in a fourth embodiment. In the fifth embodiment, it is a diagram for explaining a region of image data that is a target of calculation of the total amount of colored ink and a unit region of a corresponding mask. It is a block diagram for demonstrating the flow of the conversion process of the image data in 7th Embodiment. It is a figure for demonstrating the three-dimensional LUT used in 1st Embodiment. It is a figure for demonstrating the three-dimensional LUT used in 7th Embodiment. It is a figure for demonstrating the other example of the three-dimensional LUT used in 7th Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Image quality improving liquid)
First, image quality improving liquid and gloss improvement used in the embodiment of the present invention are defined as follows.

  In the present invention, the image quality improving liquid means a colorless and transparent liquid that improves at least the gloss of a recorded image. Further, the improvement in gloss refers to bringing the gloss level described later and the image clarity value close to desired values.

(Glossiness and image clarity evaluation method)
Next, in the embodiment of the present invention, the glossiness and image clarity of the surface of the recording medium, which is a reference for evaluating the gloss uniformity in the image, and the evaluation method will be described.

  Glossiness and image clarity are indexes for evaluating the glossiness of recording media and images. Below, the evaluation method of glossiness and image clarity, and the relationship between glossiness and image clarity are demonstrated.

  FIGS. 2A to 2D are diagrams for explaining glossiness and haze. As shown in FIG. 2A, the specular glossiness (hereinafter referred to as glossiness) of 20 ° and the haze value are obtained by reflecting reflected light reflected on the surface of the printed material with a detector (for example, B-4632 manufactured by BYK-Gardner). (Japanese name: micro-haze plus) The reflected light is distributed at an angle around the axis of the specularly reflected light, and as shown in FIG. The degree is detected, for example, with an opening width of 1.8 ° at the center of the detector, and the haze is detected outside the range, for example, ± 2.7 °, that is, when reflected light is observed. The reflectance with respect to the incident light of the specularly reflected light forming the central axis of the distribution is defined as the glossiness, and the measured scattered light generated in the vicinity of the specularly reflected light in the distribution of the reflected light is haze or It is defined as the haze value. The units of the glossiness and haze value measured by the detector are dimensionless, the glossiness conforms to JIS standard K5600, and the haze conforms to ISO standard DIS13803.

  The image clarity is measured using, for example, JIS H8686 “Method for measuring the image clarity of anodized films of aluminum and aluminum alloys” and JIS J7105 “Testing method for optical properties of plastics”, and the clarity of the image reflected on the recording medium. Represents For example, when the illumination image reflected on the recording medium is blurred, the image clarity value is low.

  FIGS. 2B and 2C are diagrams showing that the amount and direction of reflected light differ depending on the roughness of the printed image surface. As shown in these figures, generally, as the surface becomes rougher, the reflected light is diffused and the amount of specular reflected light is reduced. Therefore, the image clarity and the glossiness are measured as smaller values. Hereinafter, in the present embodiment, the fact that the measured value of the image clarity is smaller than the target image clarity value is described as low image clarity. Further, the fact that the measured value of the measured glossiness is smaller than the target glossiness is described as low glossiness.

(Relationship between glossiness and image clarity)
As described above, the glossiness and image clarity in the printed image differ depending on the gradation (FIG. 1). On the other hand, when the image quality improving liquid is injected together with the colored ink, the image clarity and the glossiness are further changed according to the overlapping manner. FIG. 3 is a diagram showing the difference in the state of the print surface due to the difference in the way the colored ink and the image quality improving liquid overlap. FIG. 3A shows a case where no image quality improving liquid is injected. FIGS. 3B and 3C show cases in which the image quality improving liquid is applied by normal printing and post-printing recording, which will be described later.

  In a recording method (hereinafter, referred to as normal printing) in which a portion to which the image quality improving liquid is applied on the colored ink and a portion to which the colored ink is applied on the image quality improving liquid are present relatively randomly. The unevenness on the surface of the portion tends to increase, and the image clarity and glossiness tend to decrease (FIG. 3B). Further, as the amount of the colored ink and the image quality improving liquid increases, the reduction rate of image clarity and glossiness also increases. This is considered to be because when the image quality improving liquid is applied, the dot permeability of the image quality improving liquid varies depending on the state of the base, and as a result, the dot height after fixing changes, resulting in unevenness.

  Conversely, in a recording method in which there is a relatively large time difference between the timing of applying the colored ink and the timing of applying the image quality improving liquid, the image clarity is unlikely to deteriorate, and only the glossiness is applied to the colored ink and the image quality improving liquid. There is a tendency to change greatly according to the amount (FIG. 3C). In particular, in a recording method in which an image quality improving liquid is subsequently applied to colored ink (hereinafter referred to as post-printing recording), the glossiness of the image changes efficiently. That is, when an image quality improving liquid is applied on an area having a low glossiness, the glossiness increases according to the amount of the image quality improving liquid (hereinafter referred to as a second action). Further, when the image quality improving liquid is applied to a region having a high glossiness, the glossiness is lowered (hereinafter referred to as a third action).

To summarize the above points, the image quality improving liquid acts as follows in terms of glossiness and image clarity depending on how it is applied.
(I) By applying the image quality improving liquid in the highlight portion by the normal recording method, the refractive index of the surface of the recording paper can be increased and the glossiness can be increased (hereinafter referred to as the first action).
(Ii) By applying the image quality improving liquid by a normal recording method in halftone, the unevenness on the surface of the recording paper can be strengthened and the glossiness can be lowered (hereinafter referred to as the second action).
(Iii) By applying the image quality improving liquid in the halftone by the normal recording method, the irregularities on the surface of the recording paper can be strengthened and the image clarity can be lowered (hereinafter referred to as the third action).
(Iv) By applying the image quality improving liquid by the post-printing recording method in the shadow area, the image quality improving liquid having a relatively low refractive index is superimposed on the colored ink having a high refractive index, and the refractive index of the recording paper surface is lowered. , The glossiness can be lowered (hereinafter referred to as the fourth action).

  In accordance with the above-described operation of the image quality improving liquid, in this embodiment, normal highlight recording is performed in the highlight portion, and the glossiness is increased by the first operation described above ((1) in FIG. 1). In the halftone, normal printing is performed, and the glossiness and image clarity are lowered by the second and third actions described above ((2) and (3) in FIG. 1). In the shadow portion, post-printing is performed, and the glossiness is lowered by the above-described fourth action ((4) in FIG. 1). By these effects, the gloss uniformity can be improved by controlling the glossiness and image clarity within a desired range. Since the uneven gloss in the image is large between the highlight portion and the shadow portion, the entire gradation range is divided into two ranges, and (i) the first action in the highlight portion and (iv) the shadow portion. It is also possible to perform control only for the fourth action.

  In the present embodiment, a state where the value of the image clarity is less than 55 is “low”, a state where the value is 55 or more and less than 60 is “medium”, and a state where the value is 60 or more is “high”. Similarly, a state where the gloss value is less than 60 is “low”, a state where the gloss value is 60 or more and less than 80 is “medium”, and a state where the gloss value is 80 or more is “high”.

  Next, the configuration of the apparatus, the components constituting the ink, and the image processing used in common in the first to eighth embodiments described below will be described.

(Device configuration)
FIG. 4 is a perspective view showing the appearance of the ink jet recording apparatus applied in the present embodiment, and FIG. 5 is a perspective view showing the inside of the ink jet recording apparatus.

  In this embodiment, after a recording medium is inserted in the direction indicated by the arrow from the paper feed tray 12 shown in FIG. 4, an image is formed while the recording medium is intermittently conveyed, and the recording medium on which the image is formed is discharged. The paper is discharged to the tray 23.

  In FIG. 5, the recording head 1 mounted on the carriage 5 discharges ink from the nozzles while reciprocating along the guide rail 4 in the directions of arrows A1 and A2 together with the carriage 5, thereby forming an image on the recording medium S2. . The recording head 1 has, for example, a plurality of nozzle groups corresponding to inks of different colors and a nozzle group corresponding to an image quality improving liquid. For example, 10 colored inks described later, cyan (C), magenta (M), yellow (Y), black 1 (K1), black 2 (K2), light cyan (LC), light magenta (LM), red ( It has nine nozzle groups for ejecting R, green (G), and gray (Gray) ink, and a nozzle group for ejecting image quality improving liquid (CL). These inks of each color and the image quality improving liquid are stored in an ink tank (not shown), and supplied to the recording head 1 through the ink tank.

  In the present embodiment, the ink tank and the recording head 1 are integrated to form a head cartridge 6, and the head cartridge 6 is mounted on the carriage 5. Further, by transmitting the driving force of the carriage motor 11 to the carriage 5 by the timing belt 17, the carriage 5 is reciprocated along the guide shaft 3 and the guide rail 4 in the directions of arrows A 1 and A 2 (main scanning direction). The position of the carriage 5 during the reciprocating movement is detected by the encoder sensor 21 provided on the carriage 5 reading the linear scale 19 provided along the movement direction of the carriage.

  When recording on the recording medium, first, the recording medium S2 is sent from the paper feed tray 12 to a position where the recording medium S2 is sandwiched between the conveying roller 16 and the pinch roller 15. Thereafter, the conveyance motor 16 rotates the conveyance roller 16 via the linear wheel 20, and the recording medium S <b> 2 is conveyed to the platen 2 by the rotation of the conveyance roller. Next, when the carriage 5 performs recording for one scan in the A1 direction, the recording medium S2 is transported by a predetermined amount in the direction of arrow B, which is the sub-scanning direction, by a transport roller. Thereafter, recording is performed on the recording medium S2 while the carriage 5 scans in the A2 direction. As shown in FIG. 5, the home position is provided with a head cap 10 and a recovery unit 14, and intermittently recovers the recording head 1 as necessary.

  By repeating the above-described operation, when recording for one sheet of recording medium is completed, the recording medium S2 is ejected and recording for one sheet is completed.

  FIG. 6 is a block diagram illustrating a control configuration of the ink jet recording apparatus according to the present embodiment. The controller 100 is a main control unit having functions as a calculation unit, a discrimination control unit, and a control unit, and includes, for example, an ASIC 101 in the form of a microcomputer, a ROM 103, and a RAM 105. The ROM 103 stores a dot arrangement pattern, a mask pattern, and other fixed data. The RAM 105 has an area for expanding recording data, an area for work, and the like. The ASIC 101 reads a program from the ROM 103 and executes a series of processes for generating binary recording data for recording on a recording medium based on the input image data. Specifically, the mask pattern is selected from information corresponding to the ink ejection amount (ink ejection amount), the image data is divided, and print data corresponding to each scan is generated.

  The host device 110 is a supply source of image data to be described later. The host device may be a computer that creates and processes data such as images related to printing, or may be in the form of a reader unit for reading images. Image data, other commands, status signals, and the like output from the host device 110 are transmitted to and received 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 recording 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, a colored ink (hereinafter referred to as ink) and an image quality improving liquid containing a pigment color material used in the ink jet recording apparatus of this embodiment will be described. First, each component constituting the ink will be described.

(Ink composition)
<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. Glycerin. Lower alkyl ethers of polyhydric alcohols such as 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. Moreover, it is preferable to use deionized water (ion exchange water) as water.

<Pigment>
As the pigment, carbon black or an organic pigment is preferably used. 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.

  The black ink preferably uses carbon black such as furnace black, lamp black, acetylene black, channel black, or the like 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, manufactured by Columbia). 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 Corporation). 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 Corporation). 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.

  Specifically, for example, the following can be used as the organic pigment. 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. Among 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 the present 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 dispersions 1-4>
Pigment dispersions 1 to 4 were 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 sodium hydroxide aqueous solution. That is.

・ C. I. Preparation of Pigment Dispersion 1 Containing Pigment Red 122 10 parts of pigment (CI Pigment Red 122), 20 parts of 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 Liquid 2 Containing Pigment Blue 15: 3 10 parts of pigment (CI Pigment Blue 15: 3), 20 parts of a dispersant and 70 parts of ion-exchanged water are mixed, and a batch type vertical sand mill is used. Disperse for 5 hours. 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 2 having a pigment concentration of 10% by mass.

・ C. I. Preparation of Pigment Dispersion 3 Containing Pigment Yellow 74 10 parts of pigment (CI Pigment Yellow 74), 20 parts of 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 4 Containing Pigment Black 7 Carbon black pigment (CI Pigment Black 7) 10 parts, dispersant 20 parts, and ion-exchanged water 70 parts are mixed, and 3 hours using a batch type vertical sand mill. scatter. 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 Liquid 5 Containing Pigment Red 149 10 parts of pigment (CI Pigment Red 149), 20 parts of 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 6 containing Pigment Green 7 10 parts of pigment (CI Pigment Green 7), 20 parts of 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)
After mixing each component shown in FIG. 7 and stirring sufficiently, pressure filtration is performed with a cellulose acetate filter (manufactured by Advantech) having a pore size of 0.8 μm to prepare inks 1 to 11.

  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 at least a liquid for controlling gloss. As long as the same effect can be obtained, the image quality improving liquid is not limited to the above example.

  Next, image processing in this embodiment will be described.

  FIG. 8 is a block diagram for explaining the flow of image data conversion processing according to the present embodiment. Input image data represented by 8 bits (256 gradations) for each color of RGB is converted into 1 bit for each color of ink. The procedure of the image processing which converts into data and outputs is shown. This recording system includes a host device 110 and a recording device (printer) 210.

  The host device 110 is, for example, a personal computer (PC), and includes an application J0001 and the printer driver 11 for the recording device according to the present embodiment. The application J0001 is a process for creating image data to be passed to the printer driver 11 described later based on information specified by the user on the UI screen on the monitor of the host device 110, and a process for setting recording control information for controlling printing. Execute.

  FIG. 9 is a diagram showing a configuration example of the image data information and the recording control information as described above. 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 any one type of recording medium is defined among plain paper, glossy paper, postcard, and printable disc. Furthermore, the recording quality information describes the quality of the recording, and any one of “clean”, “standard”, “fast” and the like is defined.

  The image data and recording control information processed by the application are transferred to the printer driver 11 at the time of recording. The printer driver 11 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), data of 256 gradations in which each of R, G, and B is represented by 8 bits is used, and R, 8 bits each having a different color gamut. Convert to G and B data (RGB values).

  The post-processing J0003 is an 8-bit color separation that is a combination of ink that reproduces the color represented by the R, G, B data on which the color gamut has been mapped based on the three-dimensional LUT for the post-processing. Convert to data. In this embodiment, since 10 colors of inks of C, M, Y, K1, K2, LC, LM, R, G, and Gray are used, the post-processing J0003 is a color that is a combination of these ink colors. Convert to decomposed data. Here, as in the previous process, the conversion is performed on the three-dimensional LUT together with the interpolation calculation. Furthermore, 8-bit color separation data CL of an image quality improving liquid that reproduces a desired glossiness in the combination of the inks is also generated.

  The γ correction J0004 performs density value (gradation value) conversion for each color 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 the present embodiment, 256-bit 8-bit data is converted into 17-gradation 5-bit data using an error diffusion method. The 5-bit image data is data serving as an index for indicating a dot arrangement pattern in the dot arrangement patterning process in the printing apparatus. The data quantized to 17 gradations of each color indicates gradation value information indicating any gradation of levels 0 to 16.

  The print data creation process J0006 generates the recording control information and the 5-bit print data created by the quantization unit J0005. The print data generated as described above is supplied to the recording apparatus J0013.

  When print data is sent to the recording device 210 by the host device 110, the recording device 210 performs dot arrangement patterning processing J0007 and mask processing J0008 on the input 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 indicating whether or not the recording apparatus ejects ink can be obtained. FIG. 10 shows a 17-tone dot arrangement pattern used in this embodiment. In the dot arrangement pattern of FIG. 10, an area where black dots are present indicates an area where dots are not formed, and a white area indicates an area where dots are not formed. In the dot arrangement patterning process J0007, each pixel represented by 5-bit data of gradation levels 0 to 16, which is an output value from the quantization process J0005, corresponds to the gradation value (level 0 to 16) of the pixel. The index is expanded to the dot arrangement pattern. Thus, the presence / absence (ejection / non-ejection) of ink dots is defined in a plurality of areas within one multi-valued pixel. For multi-valued 1-pixel (5-bit) input data, resolution conversion is performed using a binary 4 × 4 area as a unit area, and 1-bit binary data of “1” or “0” is arranged, respectively.

  In the mask process J0008, a plurality of mask patterns that are complementary to each other are used to convert the dot arrangement of each color determined by the dot arrangement patterning process J0007 into data with print scanning timing information added thereto. This mask process will be described in detail later. Then, print data for each print scan in multi-pass printing is generated for each color of C, M, Y, K1, K2, LC, LM, R, G, and Gray by mask processing. Note that multi-pass printing refers to a printing method in which an image in a recording area is completed by scanning the same printing area a plurality of times.

  The generated print data is supplied to the head drive circuit J0009 at an appropriate timing in a plurality of print scans performed in multipass printing. The recording data input to the driving circuit J0009 is converted into driving pulses for the recording head 1, and ink is ejected from the recording head 1 for each color at a predetermined timing. Thereby, ink is ejected according to the recording data, and an image is recorded on the recording medium.

  Multipass recording is a recording method in which a predetermined recording area (unit area) is scanned with a recording head a plurality of times to complete an image in the predetermined recording area. FIG. 11 schematically shows how this multi-pass recording is performed. The recording head 1 applied to the present embodiment actually has 768 nozzles, but in order to simplify the illustration in FIG. 11, it is assumed that the recording head 1 has 16 nozzles P0001, and an image is obtained by four recording scans. It will be described as being formed.

  The nozzle P0001 is divided into first to fourth nozzle groups, and each nozzle group includes four nozzles. In multipass printing, a unit area is printed by a plurality of scans, and a mask is used as means for dividing image data to be printed into a plurality of parts. The mask P0002 is composed of mask patterns P0002 (a) to P0002 (d), and defines the print allowable areas of the first to fourth nozzle groups, respectively.

  In the mask pattern, a black area indicates a recording allowable area that allows dot recording, and a white area indicates a non-recording area that does not allow dot recording. The first to fourth 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 areas = 16 areas is completed. It becomes the composition which is done. 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 intermittently conveyed in the direction of the arrow in the figure by the width of the nozzle group (by four nozzles in this figure). Therefore, the same recording area (area corresponding to the width of each nozzle group) of the recording medium is configured such that an image is completed by four recording scans. By performing an AND process on such a mask pattern and the binary image data obtained by the above-described dot arrangement patterning process, binary recording data to be recorded in each recording pass is determined.

  In the mask pattern, the ratio of the number of print permitting areas in each print scan is defined by duty (%). That is, the area corresponding to the 16 areas is defined as 100%, and the duty in each printing scan is represented by the ratio of the number of allowable areas in each printing scan. Mask patterns P0002 (a) to P0002 (d) are mask patterns in which the number of print permitting areas in each print scan is evenly distributed, and the duty of each print scan is 25%.

(First embodiment)
FIG. 12 is a flowchart showing a flow of processing for selecting a mask pattern of an image quality improving liquid according to the amount (ejection amount) of the image quality improving liquid based on image data of a predetermined area, which is a characteristic configuration of the present embodiment. . In the figure, in step S1, print data of each colored ink in a predetermined area is received, and in step S2, the ink ejection amount is calculated. Further, in steps S3 to S5, the type of mask in the recording area based on the print data is determined. In step S6, data (selection mask data) for selecting a mask to be used is generated, and the process ends.

In step S1, the print data in the predetermined area uses the binary 4 × 4 areas (600 dpi × 600 dpi) used in FIG. 10 as a unit area.
In step S 2, the unit area ejection amount is the sum of the ejection amounts of the respective colored inks calculated based on the print data generated by the print data creation process J 0006 in FIG. 8 (hereinafter referred to as the total ink ejection amount). ). The value of the shot amount is 100% when the dots are shot in all 16 areas constituting the unit area, and 50% when the dots are shot in the eight areas. The maximum total driving amount is 100%.

  In step S3, a mask to be used for a predetermined region is determined with reference to the mask type of the image quality improving liquid corresponding to the total ink ejection amount shown in FIG. As shown in the drawing, the image quality improving liquid selects the normal printing recording mask at the highlight portion where the ink shot amount in the predetermined area is less than 15% (step S4). Thereby, the glossiness is increased by the first action (1) described above. Further, in the halftone where the ink shot amount is 15% or more and less than 50% (less than a predetermined amount), the image quality improving liquid selects the normal printing mask (step S4). Accordingly, the glossiness and image clarity are lowered by the second action (2) and the third action (3) described above. Further, in the shadow portion where the ink shot amount is 50% or more (predetermined amount or more), the post-printing recording mask is selected as the image quality improving liquid (step S5). As a result, the glossiness is lowered by the fourth action (4) described above.

  In step S6, mask selection data is generated, and mask processing is performed from the selection data using a preset normal recording mask pattern or post-printing recording mask pattern in mask processing J0008 of FIG.

  Next, the characteristics of the two masks used in steps S4 and S5 will be described with reference to FIG. FIG. 13A shows an image quality improving liquid normal recording mask (first mask) and a recording duty (recording rate) defined thereby. FIG. 5B shows an image quality improving liquid post-printing recording mask (second mask) and a recording duty (recording rate) defined thereby. Further, FIG. 3C shows a colored ink mask and a recording duty (recording rate) defined thereby. The numerical value in each permissible area indicates how many scans are recorded. For example, “1” described in the area of the mask M1 in FIG. 13C indicates an area recorded by the first scan. Similarly, “2” is an area recorded by the second scan, “3” is an area recorded by the third scan, and “4” is an area recorded by the fourth scan. Show. That is, each of the masks M1 to M3 shown in FIG. 13 is composed of four mask patterns (P0002 (a) to (d) in FIG. 11) like the mask shown in FIG. Two mask patterns are shown together.

  The image quality improving liquid post-printing recording mask (hereinafter simply referred to as post-printing recording mask) M2 is a mask having a higher duty in the latter half of scanning than the image quality improving liquid normal recording mask (hereinafter simply referred to as normal recording mask) M1. It is. That is, in the normal recording mask (first mask) M1 shown in FIG. 13A, the number of recording allowable areas in the first to fourth recording scans is four. On the other hand, in the post-printing recording mask (second mask) M2 shown in FIG. 5B, the number of print permitting areas is one for the first recording scan, three for the second recording scan, and third recording. There are five for scanning and seven for the fourth recording scan. Compared to the post-printing mask M2, the normal mask (first mask) has a smaller print allowance area recorded in the latter half of the scan (the ratio at which the image quality improving liquid is discharged is lower).

  FIG. 13D is a diagram for explaining how the colored ink and the image quality improving liquid overlap. Regarding the mark in the pixel, ◯ indicates an area where the image quality improving liquid is recorded in a later scan than the ink, and the image quality improving liquid is applied above the colored ink. Similarly, Δ indicates an area where the colored ink and the image quality improving liquid are recorded by the same scan, and the image quality improving liquid is not necessarily applied on the colored ink in this area. X indicates an area where the image quality improving liquid is recorded in the previous scan than the colored ink, and the area where the image quality improving liquid is applied below the colored ink.

As shown in FIG. 13D, the number of print-allowable areas where the image quality improving liquid is applied on the colored ink is greater when the post-printing recording mask M2 is used than when the normal recording mask M1 is used. (Mark ○ in FIG. 13D) is relatively high. Therefore, the post-printing recording mask M2 is a mask that efficiently controls the glossiness while suppressing a decrease in image clarity.
Therefore, by using these masks in combination, it is possible to reduce the occurrence of uneven glossiness of the image, and an image having uniform gloss can be obtained. In particular, the difference in glossiness and image clarity between the highlight portion and the shadow portion is reduced, and the uniformity of gloss in the image is improved.

  In this embodiment, the implantation amount serving as a reference for mask selection is classified into three stages as shown in FIG. 14, but the selection of the mask is performed by a normal recording mask (first mask) and a post-printing recording mask (first mask). 2 masks) are selected. However, the present invention is not limited to this. For example, it is also possible to use a mask that has a print allowance area that is recorded in the second half scan even in the halftone than in the first half scan. Further, at that time, the difference in the print allowable area between the second half scan and the first half scan can be larger in the halftone than in the shadow portion. Further, the highlight portion is not limited to a form using a normal recording mask, and a leading mask (a mask in which the recording allowance area of the first half scanning is larger than the second half scanning) can be used, A post-mask can also be used. In either case, the difference in the printable area between the second half scan and the first half scan increases as the amount of ink hitting increases in the highlight, halftone, and shadow areas. The same effects as those of the above embodiment can be obtained. In addition, the present invention controls how the image quality improving liquid overlaps with the colored ink so that the glossiness and image clarity of the image, which varies depending on the amount of colored ink applied, approach a desired range. Therefore, the amount of driving amount may be more than three steps or less.

  Multi-pass printing is not limited to four passes, and is not limited to the number of passes, and the effects of the present embodiment can be obtained. In addition, although multipass printing has a complementary relationship by a plurality of printing passes, it does not necessarily have a complementary relationship, and dots may be thinned out or increased.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. Items other than the characteristic items of the second embodiment described below are the same as those of the first embodiment. In the first embodiment, as the mask of the image quality improving liquid, a post-printing recording mask having a higher duty in the latter half than the normal recording mask is used. On the other hand, in the second embodiment, a mask as shown in FIG. 15 is used in combination in order to control the glossiness and image clarity more efficiently.

  That is, in the second embodiment, the normal recording mask M21 for recording the image quality improving liquid within the scan for completing the image by recording with the colored ink, and the image quality improving liquid for the scanning after completing the image by recording with the colored ink. Are used in combination with a post-recording recording mask M22 for recording the image. 15A is a schematic diagram showing a normal recording mask M21 and its duty, FIG. 15B is a schematic diagram showing a post-printing recording mask M22 and its duty, and FIG. 15C is a schematic diagram showing a colored ink mask and its duty. is there.

  In the multipass printing method in which the printing operation is completed by four printing scans, the normal printing mask M21 and the colored ink mask M23 are masks that complete the application of the image quality improving liquid and the ink application in the first two scans. is there. The post-printing recording mask M22 is a mask that completes the application of the image quality improving liquid in the second half of the scanning scanning.

  FIG. 13D is a diagram for explaining how the ink and the image quality improving liquid overlap. A circle indicates an area where the image quality improving liquid is recorded in a later scan than the ink, and a cross indicates an area where the image quality improving liquid is recorded in a previous scan than the ink. As shown in FIG. 13D, with the combination of the colored ink mask M23 and the post-printing recording mask M22 of the image quality improving liquid, it is possible to apply the image quality improving liquid on the colored ink in all the print permitting areas. is there. Accordingly, it is possible to efficiently control only the glossiness without degrading the image clarity of the image, thereby reducing the occurrence of uneven glossiness of the image, and obtaining an image having a uniform glossiness. Can do.

(Third embodiment)
Next, a third embodiment of the present invention will be described. Matters other than the characteristic items of the third embodiment described below are the same as those of the first embodiment. In the first embodiment, the method of applying the image quality improving liquid is selected according to the total amount of colored ink that is driven into a predetermined area. On the other hand, in the third embodiment, in addition to the total amount of colored ink applied, the number of inks used for recording in a predetermined area, that is, the color to be recorded in the predetermined area is the primary color, the secondary The recording method for the image quality improving liquid is selected according to whether the color or the tertiary color is used.

  FIG. 16 is a table showing the relationship between the number of inks used for recording an image in a predetermined area, the amount of hit, and the mask to be selected. Image regions that use a large number of inks tend to have low image clarity. Therefore, in an area where the primary color is recorded and the amount of ink applied to a predetermined area is less than 75%, a normal printing recording mask is selected as a mask for the image quality improving liquid, while the amount of ink applied is 75% or more. The post-printing recording mask is selected for the area of. In addition, a normal printing mask is selected as a mask for the image quality improving liquid in an area where the secondary color is recorded and the ink printing amount for a predetermined area is less than 50%, while the ink printing quantity is 50% or more. Select a post-recording recording mask. Furthermore, a normal printing recording mask is selected for an area where the ink is applied in a tertiary color and the ink printing amount for a predetermined area is less than 15%, while a post-printing recording mask is used for an area where the ink printing quantity is 15% or more. select.

  As described above, according to the third embodiment, according to the number of inks to be used and the hit amount, it is selected whether to apply the image quality improving liquid by the normal recording method or the post-printing recording method. In addition, the glossiness and image clarity can be controlled more appropriately. For this reason, it is possible to obtain an image having more uniform gloss while suppressing occurrence of uneven gloss of the image.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. Items other than the characteristic items of the fourth embodiment described below are the same as those of the first embodiment. In the first embodiment, the mask of the image quality improving liquid is selected according to the total amount of colored ink to be ejected into the predetermined area, but in this fourth embodiment, the mask is selected according to the amount of colored ink to be ejected. It has become a choice. This is because the image clarity of the recorded image changes not only with the amount of ink used but also with the combination thereof.

  FIG. 17 is a table for selecting an image quality improving liquid application method according to the amount of the mixed color (secondary color) of cyan ink (C ink) and magenta ink (M ink) in the fourth embodiment. It is a figure which shows an example. As shown in the drawing, it is selected whether to perform normal recording or post-printing recording according to the amount of C ink and M ink. Thus, it is possible to control the glossiness and image clarity by the amount of ink applied.

  In the above description, the case of recording a secondary color image using C ink and M ink has been described as an example. However, the case of forming a secondary color image with other colored inks is the same as in FIG. A selection table is set according to the amount of colored ink applied. In the fourth embodiment, a case where an image of a secondary color is recorded has been described as an example. However, the case where an image is recorded not only in a secondary color but also in a tertiary color or more is described above. It is also possible to set the application method of the image quality improving liquid as described above. That is, according to the present invention, the selection table can be set even for tertiary colors or more as long as the number of inks is less than the number of colored inks mounted in the recording apparatus main body.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. Matters other than the characteristic items of the present embodiment described below are the same as those of the first embodiment. In the first embodiment, 4 × 4 areas are used as unit areas of a mask, and a total amount of colored ink is calculated based on recording data corresponding to the unit area, and an image quality improving liquid is calculated based on the total amount of injection. The mask is selected. On the other hand, in the fifth embodiment, information on the amount of colored ink applied is calculated in the unit area of the mask of 16 × 16 areas.

  FIG. 18 is a diagram for explaining an image data area to be a target in calculating the total implantation amount and a corresponding mask unit area. FIG. 18A is a diagram showing information on the total amount of colored ink applied. 18B shows a state in which the type of image quality improving liquid mask is selected in the first embodiment, and FIG. 18C shows a state in which the type of image quality improving liquid mask is selected in the fifth embodiment. Each state is shown. Hereinafter, the fifth embodiment will be described in comparison with the first embodiment.

  As described above, in the first embodiment, the masking data of the image quality improving liquid is generated by calculating the total amount of colored ink applied to the input of image data (17 gradations) of one pixel (step). S1-S6). Then, based on the mask selection data, a mask process is performed on the recording data of the image enhancement liquid using a mask pattern of 4 × 4 areas. Here, selection of the mask used for applying the image quality improving liquid is performed as shown in FIG. That is, when the total amount of colored ink applied to 4 × 4 areas is less than 50%, a normal recording mask (indicated by A in the figure) is selected. When the total driving amount is 50% or more, a post-printing recording mask (indicated by B in the figure) is selected.

  On the other hand, in the fifth embodiment, in each 2 × 2 pixel (4 pixels) image data (17 gradations), a mask is selected based on the average of the total amount of colored ink applied at these pixels. That is, among the pixels shown in FIG. 18A, an average value of the total amount of image data (17 gradations) for each of 2 × 2 pixels (4 pixels) is obtained. When the average value is less than 50%, a normal recording mask (indicated by A in the figure) is selected. When the average value is 50% or more, a post-recording recording mask (indicated by B in the figure) is selected. . In FIG. 18A, the total shot amount of the four pixels is 30%, 30%, 60%, and 40%, and the average value is 40%. Therefore, the normal recording mask (A ). Similarly, since the total shot amount of each pixel in the next unit region in FIG. 18A is 30%, 100%, 30%, and 120%, respectively, the average value is 70%. All these four pixels are processed with the normal recording mask (B). Furthermore, since the total shot amount of each pixel in the next unit area is 110%, 120%, 110%, and 130%, respectively, the average value is 117.5%. Processing is performed using the post-recording recording mask (B).

  As described above, the unit area of the image data for performing mask selection may be an area including a plurality of gradation value data. In the present embodiment, 2 × 2 pixel image data (17 gradations) is used as a unit area, and a mask is selected based on an average value of the total amount of colored ink applied to the pixels. It is not limited to 2 × 2 pixels. In addition, as long as the mask process is performed using a plurality of pixels as a unit region, the mask selection method for the image quality improving liquid is not limited to the average value. For example, for a pixel (17 gradations) whose total shot amount is equal to or smaller than a certain value, the colored ink shot amount corresponding to the pixel is weighted to calculate the total shot amount of the entire unit area, and the calculated value The mask for the image quality improving liquid may be selected based on the above.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. Note that matters other than the features of the sixth embodiment described below are the same as in the first embodiment. In the sixth embodiment, multi-value image data (256 gradation image data) before quantization is used as information corresponding to the amount of colored ink applied. That is, in the sixth embodiment, as shown in FIG. 19, the mask for the image quality improving liquid is selected based on the input of the image data (256 values) after the preprocessing J0002. In FIG. 19, processes other than the post-stage / mask selection process J0003a and the mask selection data generation process J0003b are the same as those in the first embodiment.

  In the first embodiment, in the post-stage process J0003, based on the post-process three-dimensional LUT, the input image data composed of R, G, and B is converted into color separation data C, M, Y, K1, and K2. , LM, LC, R, Gray, and CL data. FIG. 20 shows a conceptual diagram of a three-dimensional LUT. FIG. 20 shows each of the 256 gradation R, G, B value lattice points reproduced by the recording apparatus, and the corresponding C, M, Y, K1, K2, LM, LC, R, G, Gray. And CL values are assigned. (R, G, B) = (0, 0, 0) indicates black (K) having the lowest brightness, and (R, G, B) = (255, 255, 255) indicates white having the highest brightness (W ).

  On the other hand, in the sixth embodiment, mask selection information is also added to the three-dimensional LUT. That is, in the sixth embodiment, in the subsequent stage / mask selection processing J0003a in FIG. 19, mask selection data (mask selection information) SD is generated based on the three-dimensional LUT in the present embodiment, and the selection data is masked J0008. Pass to.

  FIG. 21 shows a three-dimensional LUT used in the sixth embodiment. The three-dimensional LUT shown here has information on a normal recording mask (A) or a post-recording recording mask (B) as mask selection data. In the ink jet recording, the shadow portion tends to increase the type of colored ink to be used and the total shot-in amount compared to other gradations. For example, black ink enters in addition to chromatic colors. Further, in the composite color using C, M, and Y, the total driving amount increases. Accordingly, the post-printing mask (B) is used in the shadow portion including the darkest portion (the portion indicated by the oblique lines in FIG. 21), and the normal mask (A) is selected in the other regions.

As described above, mask selection may be performed based on image data (256 values) before quantization. That is, when the gradation value of the image represented by the image data is less than the predetermined gradation value, the normal mask (A) is selected, and the gradation value of the image is equal to or larger than the predetermined gradation value. For this, the normal mask (B) is selected. In the sixth embodiment, the mask selection method is classified into the shadow portion and the others. In other words, classification was performed depending on brightness. However, the mask selection is not limited to the selection based on the above classification. That is, the sixth embodiment is characterized in that the mask of the image quality improving liquid is selected based on the RGB value as information indicating the amount of colored ink applied, and the uniformity of glossiness and image clarity is improved. Is. Therefore, other configurations can be adopted as long as the same effect can be obtained by using RGB values for selection of the mask for the image quality improving liquid. For example, as shown in FIG. 22, the post-recording recording mask (B) may be selected within a range of hue and saturation (range shown by oblique lines). The input image data is not limited to RGB, and may be image data represented by L ^* a ^* b ^* . Furthermore, the input image data is image data after color conversion into the plurality of colored inks. May be.

(Other embodiments)
In the first embodiment, as shown in FIG. 8, the pre-processing J0002, the post-processing J0003, the γ processing J0004, the quantization unit J0005, and the recording data creation processing J0006 are executed by the host device 110. Further, the dot arrangement patterning process J0007 and the mask process J0008 are performed by the recording apparatus (printer) 210. However, the present invention is not limited to this form. For example, a form in which a part of the processes J0002 to J0005 being executed by the host apparatus 110 is executed by the recording apparatus 210 may be executed, or all processes may be executed by the host apparatus 110. . Alternatively, the processing J0002 to J0008 may be executed by the recording device 210.

  In the first embodiment, as information corresponding to the amount of ink to be applied, the total amount of colored ink applied is calculated with respect to the input of the image data (17 values) after the print data creation process J0006 is performed. Based on the information, the mask for the image quality improving liquid is selected. However, the present invention is not limited to this. The information corresponding to the amount of colored ink applied may be, for example, binary image data after the dot arrangement patterning process. In this case, the mask may be selected by counting the number of areas in which dots are to be printed after the binary development. For example, in the dot arrangement pattern shown in FIG. 10, the number of areas into which ink dots are to be printed out of 16 pixels that are unit areas is counted. When the counted number of areas is 0 to 10 areas, the normal recording mask is selected, and when it is 10 to 16 pixels, the post-printing recording mask is selected.

  In the second embodiment, the recording of the colored ink and the image quality improving liquid is completed and discharged in four recording scans for one insertion of the recording medium. However, the present invention is not limited to this mode. It is not something that can be done. For example, after the normal recording of the colored ink and the image quality improving liquid is completed in two scans for the insertion of the recording medium and the paper is discharged, the user manually inserts the recording medium again, and after the image quality improving liquid It is also possible to perform hitting recording. In this case, the recording medium is inserted twice in order to transport the recording medium to the recording unit a plurality of times. However, this operation can be automatically performed by a mechanism for switching back the recording medium. is there.

1 Recording Head 5 Carriage 100 Controller 101 ASIC
103 ROM
104 RAM
110 Host device 210 Recording device M1, A Normal recording mask (first mask)
M2 and B

That is, in the first aspect of the present invention, an image is formed on a recording medium with a plurality of types of ink having different colors and an image quality improving liquid for changing at least one of the glossiness and image clarity of the image. A recording head for discharging on the basis of the image data; and the plurality of types of ink and the image quality improving liquid are discharged while scanning the recording head with respect to the recording medium, and a plurality of times for a unit region of the recording medium. Recording control means for forming an image by scanning, acquisition means for acquiring image data indicating an image to be recorded in the unit area by RGB gradation values, and the image data acquired by the acquisition means And a conversion means for converting into color separation data indicating the amount of each of the plurality of types of ink applied to the unit area and the image quality improving liquid. And determining means for determining an amount of the image quality improving liquid to be applied to the unit area in each of the plurality of scans based on an RGB value of the image data acquired by the acquiring means, The recording control unit causes the recording head to apply the plurality of types of ink to the unit area based on the color separation data converted by the conversion unit, and the plurality of scans determined by the determination unit. The image quality improving liquid is applied to the unit region in each of the plurality of scans based on the amount of the image quality improving liquid for each.
The second aspect of the present invention is an image in which a plurality of types of ink having different colors and an image quality improving liquid for changing at least one of glossiness and image clarity of an image are formed on a recording medium. A recording step in which the plurality of types of ink and the image quality improving liquid are ejected while the recording head is scanned with respect to the recording medium based on the image data of the recording medium, and an image is formed by scanning the unit region of the recording medium a plurality of times. An acquisition step of acquiring image data indicating an image to be recorded in the unit region with RGB gradation values; and the plurality of types of inks that apply the image data acquired in the acquisition step to the unit region And a conversion step for converting into color separation data indicating the amount of each of the image quality improving liquid and the amount of the image quality improving liquid, wherein each of the plurality of scans includes a preceding step. A determination step of determining an amount of the image quality improving liquid to be applied to the unit area based on RGB gradation values of the image data acquired by the acquisition step; Based on the color separation data, the recording head applies the plurality of types of ink to the unit area, and based on the amount of the image quality improving liquid for each of the plurality of scans determined by the determination step. The image quality improving liquid is applied to the unit area in each of the plurality of scans to the recording head.

According to a third aspect of the present invention, an image formed on a recording medium includes a plurality of types of inks having different colors and an image quality improving liquid for changing at least one of glossiness and image clarity of the image. A recording head for discharging based on image data, and a plurality of times of scanning the unit area of the recording medium by discharging the plurality of types of ink and the image quality improving liquid while the recording head is scanned with respect to the recording medium Recording control means for forming an image in accordance with a mask pattern indicating a recording allowable area in the unit area, first storage means for storing a plurality of different mask patterns, and recording in the unit area Acquisition means for acquiring image data indicating a power image by RGB gradation values, and the RG of the image data acquired by the acquisition means A second storage means for storing a three-dimensional lookup table indicating color separation data corresponding to the amount of each of the plurality of types of ink to be applied to the unit region and the image quality improving liquid according to a value; Conversion means for converting the image data into the color separation data based on the RGB values of the image data obtained by the means and the three-dimensional lookup table, the inkjet recording apparatus comprising: The dimension lookup table shows a correspondence relationship between the mask pattern used for applying the image quality improving liquid to the recording medium and the RGB value, and the RGB value of the image data acquired by the acquisition unit and the RGB value Based on the three-dimensional lookup table, from the plurality of mask patterns stored in the first storage means, And determining means for determining the mask pattern used for applying the quality improving liquid to the recording medium, wherein the recording control means applies a plurality of times to the recording head according to the mask pattern determined by the determining means. The image quality improving liquid is applied to the unit region in each of the scans.
According to a fourth aspect of the present invention, there is provided the recording head for ejecting a plurality of types of inks having different colors and an image quality improving liquid for changing at least one of glossiness and image clarity of the image. The unit areas are ejected from the plurality of types of ink and the image quality improving liquid based on image data of an image formed on the recording medium while being scanned with respect to the recording medium, and each of the unit areas of the recording medium is scanned a plurality of times. Acquired by the recording step of forming an image according to a mask pattern indicating a recording allowable area, an acquisition step of acquiring image data indicating an image to be recorded in the unit area by RGB gradation values, and the acquisition step In accordance with the RGB values of the image data, the amount of each of the plurality of types of ink applied to the unit area and the image quality improving liquid A second storage step for storing a three-dimensional lookup table indicating color separation data to be performed, and the image data based on the RGB values of the image data acquired by the acquisition step and the three-dimensional lookup table Conversion step of converting the color separation data into the color separation data, wherein the three-dimensional lookup table includes the mask pattern and the RGB values used for applying the image quality improving liquid to the recording medium From the plurality of different mask patterns stored in the first storage step based on the RGB values of the image data acquired in the acquisition step and the three-dimensional lookup table. A determination step for determining the mask pattern used for applying the image quality improving liquid to the recording medium is further performed. Has, according to the mask pattern determined by the determining step, the image quality improving liquid to the unit area is applied in each of the plurality of scans to the recording head, characterized in that.

Claims (2)

A recording head that discharges at least one kind of colored ink containing a color material and an image quality improving liquid that changes at least one of glossiness and image clarity of an image recorded on the recording medium by the colored ink; The head is an inkjet recording apparatus that scans a unit region of a recording medium a plurality of times, records an image on the recording medium, and applies the image quality improving liquid to the image.
A control means for controlling the amount of image quality improving liquid applied to the unit area in each of a plurality of scans;
The control means includes
A first mask and a second mask for dividing recording data for discharging the image quality improving liquid from the recording head to the unit area into data corresponding to the plurality of scans;
Selecting means for selecting use of the first mask and the second mask according to a gradation value of an image represented by the input image data corresponding to the unit region;
The second mask is determined such that a recording rate of print data in a later scan among the plurality of scans is higher than that of the first mask.
The selection means selects the first mask when the gradation value of the image represented by the input image data corresponding to the unit area is less than a predetermined gradation value, while the input image data When the gradation value of the image represented by is greater than or equal to a predetermined gradation value, the second mask is selected,
The ink jet recording apparatus, wherein the input image data is image data represented by RGB or L ^* a ^* b ^* . Using a recording head that discharges at least one kind of colored ink containing a color material and an image quality improving liquid that changes at least one of glossiness and image clarity of an image recorded on a recording medium by the colored ink, An inkjet recording method for recording an image on the recording medium by scanning a recording head a plurality of times with respect to a unit area of the recording medium, and applying the image quality improving liquid to the image,
A control step of controlling the amount of image quality improving liquid applied to the unit area in each of a plurality of scans;
The control step includes
Of the first mask and the second mask for dividing the recording data for discharging the image quality improving liquid from the recording head to the unit area into data corresponding to the plurality of scans, the unit area A selection step of selecting use of the first mask and the second mask according to the gradation value of the image represented by the corresponding input image data,
The second mask is determined such that a recording rate of print data in a later scan among the plurality of scans is higher than that of the first mask.
The selection step selects the first mask when the gradation value of the image represented by the input image data corresponding to the unit area is less than a predetermined gradation value, while the input image data When the gradation value of the image represented by is greater than or equal to a predetermined gradation value, the second mask is selected,
The ink jet recording method, wherein the input image data is image data represented by RGB or L ^* a ^* b ^* .