Recording device and method of control

Abstract

To solve such a problem that the fixing characteristics of the second side, which is a rear surface, of a recording medium varies depending on a recording state of an image on a first side, which is a front surface, of the recording medium when recording images on both sides of the recording medium.SOLUTION: Recording a determination pattern for determining the fixing characteristics of a second side according to the recording state on a first side of a recording medium can appropriately determine the fixing characteristics of the second surface.SELECTED DRAWING: Figure 22

Description

[Technical Field]

[0001] The present invention relates to a recording apparatus and a control method for recording an image on a recording medium. [Background technology]

[0002] The characteristics related to ink fixation on a recording medium include the wettability and absorbency of the ink on the recording medium. Patent Document 1 describes a method of determining the type of recording medium to be used for recording, and using a reaction liquid that reacts with the ink colorant to cause aggregation if the recording medium has low absorbency, and performing recording without using a reaction liquid if the recording medium has high absorbency. This makes it possible to promote ink fixation by using a reaction liquid even when using a recording medium with low absorbency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-149735 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, when a recording medium whose ink fixation characteristics are unknown is used, it may not be possible to set appropriate recording conditions. In such cases, it is not possible to set appropriate recording conditions according to the recording medium. In particular, when recording images on both sides of a recording medium, the appropriate recording conditions for the back side of the recording medium may differ depending on whether or not there is recording on the front side of the recording medium, or the density of that recording.

[0005] In response to such problems, an object of the present invention is to provide a recording apparatus and a control method that can appropriately determine fixing characteristics when recording images on both sides of a recording medium. [Means for solving the problem]

[0006] The present invention is a recording means for recording an image by applying ink containing a colorant and a reaction liquid not containing a colorant onto a recording medium, the recording means comprising: a recording means for recording a test pattern including a first pattern and a second pattern in which the ink and the reaction liquid are applied in a different manner from the first pattern, at a position corresponding to the predetermined area on a second surface, which is the reverse side of the first surface, of the recording medium on which a uniform pattern of a predetermined density using the ink is recorded in a predetermined area on the first surface; an acquisition means for acquiring information regarding a first density of the first pattern and a second density of the second pattern; and a determination means for determining, based on the information, the fixing characteristics of a position corresponding to the area on the second surface of the recording medium on which the image of the predetermined density is recorded in a predetermined area on the first surface. [Effects of the Invention]

[0007] According to the present invention, when images are recorded on both sides of a recording medium, the fixing characteristics of the second side of the recording medium can be appropriately determined. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view schematically illustrating the general configuration of an inkjet recording apparatus according to a first embodiment. [Figure 2] 2(a) and 2(b) are diagrams showing a schematic configuration of the optical sensor shown in FIG. 1. [Figure 3] FIG. 2 is a diagram schematically illustrating an ejection port surface of a print head according to the first embodiment. [Figure 4] FIG. 2 is a block diagram showing the control configuration of the recording apparatus according to the first embodiment. [Figure 5] FIG. 2 is a diagram for explaining multi-pass printing according to the first embodiment. [Figure 6] 10(a) to 10(d) are diagrams showing the relationship between the mask patterns and ejection orifice groups used in 8-pass multi-pass printing according to the first embodiment. [Figure 7]FIG. 2 is a diagram schematically showing a screen displayed on a display for inputting information about the type of recording medium in the recording device according to the first embodiment. [Figure 8] 1(a) to 1(c) are diagrams illustrating the quantification of the "wettability" of a recording medium according to the first embodiment. [Figure 9] FIG. 1 is a diagram illustrating classification of recording media according to their "absorbency" and "wettability." [Figure 10] 5 is a flowchart showing print data generation processing (image processing) executed by the printing apparatus of the first embodiment. [Figure 11] 11 is a flowchart showing the recording condition setting process performed in step S1003 of FIG. [Figure 12] FIG. 10 is a diagram showing the relationship between the ON / OFF of air blowing, pass mask A / B, and the amount of reaction liquid applied, in relation to the combination of wettability and absorbency of the recording medium according to the first embodiment. [Figure 13] 5 is a flowchart showing a process for determining and registering the ink fixing characteristics of a recording medium according to the first embodiment. [Figure 14] 5A to 5C are diagrams illustrating test patterns printed in wettability determination according to the first embodiment. [Figure 15] 15(a) and 15(b) are diagrams illustrating the behavior of ink and reaction liquid in relation to fixation when the pattern shown in FIG. 14 is printed, and the resulting optical density. [Figure 16] 15(a) and 15(b) are diagrams showing the brightness explained in FIGS. 15(a) and 15(b). [Figure 17] 10 is a flowchart showing a process for determining the wettability of a recording medium. [Figure 18] FIG. 10 is a diagram illustrating a test pattern printed for determining absorbency. [Figure 19] 19 is a diagram illustrating the behavior of ink and reaction liquid regarding fixation when the pattern shown in FIG. 18 is printed, and the resulting optical density. [Figure 20] FIG. 19 is a diagram showing the brightness described in FIGS. 19(a) and 19(b). [Figure 21]10 is a flowchart showing a process for determining the wettability of a recording medium. [Figure 22] 10A and 10B are diagrams showing the positional relationship between the front and back of a recording medium and a pattern image when wettability determination and absorbency determination are performed on the second surface of the recording medium. [Figure 23] 10 is a flowchart showing a process for determining wettability and absorbency for a second surface of a recording medium. [Figure 24] 10 is a flowchart showing a process for determining wettability and absorbency for a second surface of a recording medium. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] [First embodiment] FIG. 1 is a side view showing a schematic configuration of an inkjet recording apparatus according to this embodiment. The inkjet recording apparatus (hereinafter simply referred to as the "recording apparatus") 1 transports a recording medium P using a transport mechanism including a pair of transport rollers 3, each consisting of a transport roller and a pinch roller. A recording head 4 scans the transported recording medium P along the X direction shown in the figure, and ink or other materials are ejected from the recording head 4 during this scan to record an image or other data on the recording medium P. In the example shown in the figure, the recording medium P is in a roll-to-roll form, in which the recording medium P is fed in a wound state and then rewound after recording. Of course, this form is not limited to this, and the recording medium P may be in the form of cut sheets, for example. Furthermore, as described later in FIGS. 7 and 12, the recording medium P may be a recording medium pre-registered for the recording apparatus or a recording medium registered by determining the type of recording medium. Types of recording media include those distinguishable by differences in wettability or ink absorbency. The recording head 4 is mounted on a carriage 5, which is movable along the X direction, enabling scanning of the recording medium P. The print head 4 has ejection ports for each type of ink, which will be described later in FIG. 3, and ejects ink from each ejection port according to print data, depositing the ink onto the print medium P. An optical sensor 2 is attached to the carriage 5, and as will be described later in FIG. 2, it acquires a predetermined pattern of reflective optical density from the ink deposited on the print medium P. A platen 6 is provided in a position opposite the scanning area of ​​the print head 4, and supports the print medium P from its back side. The platen 6 also has a suction port, which enables a suction mechanism (not shown) to suck the print medium P with a force that does not hinder its transport. The print head 4 can also be configured to be detachably attached to the carriage 5.

[0011] The recording apparatus 1 also includes a configuration for fixing ink. Specifically, a platen air blowing unit 10 is provided upstream of the recording head 4 in the transport direction of the recording medium P. This air blowing unit 10 includes a fan 10A and a heater 10B, and blows hot air at a predetermined temperature toward the portion of the recording medium onto which ink ejected from the recording head 4 is applied. This allows the ink applied to the recording medium to dry, as will be described later with reference to FIG. 11 and other figures. Meanwhile, a fixing unit 11 is provided downstream of the recording head 4, and dries and fixes the ink applied to the recording medium P after recording. The fixing unit 11 includes a substantially box-shaped housing, the open bottom of which faces the surface of the recording medium P. The housing also includes a fan 11A and a heater 11B. This allows hot air to be blown toward the recording medium P to evaporate the water and solvent contained in the ink, thereby fixing the applied ink to the recording medium. The downflow unit 12 includes a fan (not shown), and blows the hot air exhausted from the fixing unit 11 downward from the apparatus. Furthermore, the air curtain unit 13 is provided between the platen 6 and the fixing unit 11, and prevents mist of ink or the like blown by the air blown by the platen air blowing unit 10 from entering the inside of the fixing unit 11.

[0012] 2(a) and (b) are diagrams showing the schematic configuration of the optical sensor shown in FIG. 1, with FIG. 2(a) showing the light emitted from the sensor and reflected from the recording medium, and FIG. 2(b) showing the detection spot resulting from the illumination. The optical sensor 2 includes a main body 20 and a light-emitting unit 20E composed of LEDs, such as R, G, and B, and a light-receiving unit 20R composed of a photodiode. The main body 20 is fixedly mounted on the carriage 5 so that the detection spot SP is located downstream in the +Y direction from the nozzle array of the recording head 4 in the direction of movement of the carriage 5 (the direction along the Y direction shown in FIG. 2). The light-emitting unit 20E and the light-receiving unit 20R are mounted on the underside of the main body 20. The light-emitting unit 20E emits light toward the recording medium P, and the light-receiving unit 20R receives the light reflected by the recording medium P. In this case, the light EP emitted from the light-emitting unit 20E is diffusely reflected by the recording medium P, and the reflected light RP is received by the light-receiving unit 20R. The diameter of the detection spot formed when the light EP emitted from the light emitting unit 20E is diffusely reflected by the recording medium P is, for example, approximately 3 mm in diameter.

[0013] The detection signal (analog signal) of the reflected light RP received by the light receiving unit 20R is transmitted to the control circuit (not shown) of the recording device 1 via a flexible cable (not shown) or the like, and is converted into a digital signal by an A / D converter in the control circuit. When detecting the optical characteristics of the test pattern (described later), the recording medium P is conveyed in the Y direction alternately with the movement of the carriage 5, to which the optical sensor 2 is attached, in the X direction. This synchronizes with the timing based on the position signal obtained by the encoder (not shown), and the optical sensor 2 detects the density of the pattern recorded on the recording medium P as optical reflectance. In this embodiment, as described later, the test pattern on the recording medium P is irradiated with light EP and the reflection intensity reflecting the density of the pattern is detected. The reflection intensity is strong for a white recording medium P, and the reflection intensity is weaker for darker patterns.

[0014] FIG. 3 is a schematic diagram showing the nozzle surface of a print head 4 according to this embodiment. The print head 4 includes an array of nozzles for ejecting ink containing a colorant (hereinafter also referred to as "color ink," "colorant ink," or "first liquid"). Specifically, the print head 4 includes an array of nozzles 22Bk for ejecting black ink (Bk), an array of nozzles 22C for ejecting cyan ink (C), an array of nozzles 22M for ejecting magenta ink (M), and an array of nozzles 22Y for ejecting yellow ink (Y). The print head 4 also includes an array of nozzles 22RCT for ejecting a reactive liquid (RCT) (hereinafter also referred to as "second liquid") that does not contain a colorant. This reactive liquid contains a component that reacts with the colorant contained in the color ink. When the reactive liquid comes into contact with the color ink on the print medium, it causes the colorant to aggregate, suppressing bleeding of the color ink and improving its density. Note that, in this specification, the term "ink" may also include the reactive liquid.

[0015] In the print head 4, the ejection opening arrays are arranged in the order of ejection opening arrays 22Bk, 22C, 22M, 22Y, and 22RCT from left to right in the X direction of the figure. Each of these ejection opening arrays 22Bk, 22C, 22M, 22Y, and 22RCT has 1,280 ejection openings 30 that eject ink, arranged in the Y direction (arrangement direction) at a density of 1,200 dPi. In this embodiment, the amount of ink ejected from one ejection opening 30 is approximately 4.5 pL. The ink flow paths corresponding to each of the ejection opening arrays 22Bk, 22C, 22M, 22Y, and 22RCT are connected to ink tanks (not shown) that store the corresponding ink, and ink is supplied to them. In this embodiment, the print head 4 and ink tanks may be integrally configured, or may be separable.

[0016] FIG. 4 is a block diagram showing the control configuration of the recording apparatus 1 according to this embodiment. The control unit 300 includes a CPU 301 that executes processing operations such as calculations, discrimination, and control, as well as recording operations. The control unit 300 also includes a ROM 302 that stores control programs to be executed by the CPU 301, a RAM 303 used as a recording data buffer, memory 313, and an input / output port 304. The input / output port 304 is connected to various drive circuits 305, 306, 307, and 308. The drive circuit 305 drives a transport motor (LF motor) 309, which serves as a drive source for transporting the recording medium, and the drive circuit 306 drives a carriage motor (CR motor) 310. The drive circuit 307 drives ink ejection from the recording head 4, and the drive circuit 308 individually drives each of the air blowing units (11-13) shown in FIG. 1, such as the platen air blowing unit 10. The main control unit 300 is also connected to a host device (PC) 312 via an interface circuit 311.

[0017] <Multi-pass printing> The printing apparatus of this embodiment is capable of performing so-called multi-pass printing, which completes printing on a unit area of ​​the printing medium by performing multiple scans on the unit area of ​​the printing medium and conveying the printing medium an amount corresponding to the valley area between these scans. FIG. 5 is a diagram for explaining multi-pass printing according to this embodiment. In the example shown in the figure, each ejection port array (hereinafter, described as a representative "ejection port array 22") is divided in the Y direction to form eight ejection port groups A1 to A8, which correspond to unit areas 80, and printing is completed through eight scans (hereinafter, referred to as "8-pass printing"). Note that the printing medium P is conveyed downstream in the conveyance direction (Y direction in the figure) between each scan, but for simplicity of illustration, the ejection port array 22 (printing head 4) is shown moving in the direction opposite to the Y direction between each scan.

[0018] First, in a first scan (1st), the print head 4 scans with the ejection opening group A1 of the ejection opening array 22 facing a unit area 80 on the print medium P, and ink is ejected from the ejection opening group A1 in accordance with print data corresponding to the first scan. After this first scan is completed, the print medium P is transported in the Y direction a distance corresponding to one ejection opening group (an amount corresponding to the unit area 80 in the transport direction) so that the ejection opening group A2 of the ejection opening array 22 faces the unit area 80. Then, a second scan (2nd) is performed, and ink is ejected from the ejection opening group A2 into the unit area 80 in accordance with print data corresponding to the second scan. Thereafter, similarly, transport of the print medium P and ejection from the print head are alternated, and ejection from the ejection opening groups A3 to A8 is performed in third to eighth scans (3rd to 8th) on the unit area 80 to complete printing on the unit area 80.

[0019] FIGS. 6(a) to 6(d) show the relationship between the mask patterns and the ejection orifice groups used in 8-pass multi-pass printing according to this embodiment. The mask patterns are used in the mask processing used in the distribution processing described later in FIG. 10, and are patterns that correspond to the pixels that make up the image, with mask elements that allow printing of quantized data and mask elements that do not allow printing of quantized data. In the mask patterns shown in FIG. 6, mask elements shown in black indicate mask elements that allow ink ejection (printing) when the quantized data is data for ink ejection. Furthermore, mask elements shown in white indicate elements that do not allow ink ejection even when the quantized data indicates ink ejection. Furthermore, FIG. 6 shows mask patterns each having a size of 4 elements (pixels) x 8 elements (pixels). These mask patterns are repeatedly applied in the X and Y directions to perform distribution processing for all of the quantized data corresponding to each unit area. Specifically, in the Y direction, for one ejection orifice group Ak (k = 1 to 8), each mask pattern is repeatedly applied 40 times (160 ejection orifices per ejection orifice group ÷ 4 mask elements).

[0020] FIG. 6(a) shows a mask pattern applied to the quantized data of the ejection opening array 22COL for color inks (C, M, Y, Bk). FIG. 6(b) shows a mask pattern applied to the quantized data of the ejection opening array 22RCT for the reaction liquid. As shown in FIG. 6(a), among the ejection opening groups A1 to A8 corresponding to the first to eighth scans, print-permitting elements are arranged in the mask pattern applied to the ejection opening groups A2 to A8 corresponding to the second to eighth scans. Furthermore, print-permitting pixels are not arranged in the mask pattern applied to the ejection opening group A1 corresponding to the first scan. As a result, color ink is ejected only during the second to eighth scans out of the eight scans. Meanwhile, as shown in FIG. 6(b), for the ejection opening array 22RCT for the reaction liquid, among the ejection opening groups A1 to A8 corresponding to the first to eighth scans, print-permitting elements are arranged in the mask pattern applied to the ejection opening groups A1 to A7 corresponding to the first to seventh scans. Furthermore, print-permitting pixels are not arranged in the mask pattern applied to the ejection opening group A8 corresponding to the eighth scan. As a result, the reaction liquid is ejected only during the first to seventh scans out of the eight scans.

[0021] The mask patterns shown in Figures 6(a) and (b) described above are referred to as path mask A. By applying this path mask A, the reaction liquid can be ejected in the scan immediately before the scan in which the color ink is ejected. As a result, when the color ink is ejected and lands on the recording medium, the colorant of the color ink immediately comes into contact with the pre-existing reaction liquid, and the colorant begins to aggregate. As a result, it is possible to effectively reduce bleeding of the color ink. On the other hand, if the mask patterns shown in Figures 6(c) and (d) are referred to as path mask B, path mask B ejects the color ink and the reaction liquid in the same scan and causes them to come into contact. This allows the color ink to come into contact with the reaction liquid before being absorbed into the recording medium. As will be described in detail later, the above path masks A and B can be switched depending on the fixing characteristics of the ink on the recording medium, etc.

[0022] <Ink and reaction liquid> The composition of each ink will be described below.

[0023] The color inks (C, M, Y, Bk) and the reaction liquid (RCT) used in this embodiment all contain a water-soluble organic solvent. The water-soluble organic solvent preferably has a boiling point of 150°C or higher and 300°C or lower for reasons of wettability and moisture retention of the print head 4 face surface. Ketone compounds such as acetone and cyclohexanone, propylene glycol derivatives such as tetraethylene glycol dimethyl ether, and heterocyclic compounds having a lactam structure, such as N-methyl-pyrrolidone and 2-pyrrolidone, are particularly preferred. From the perspective of ejection performance, the content of the water-soluble organic solvent is preferably 3 wt% or higher and 30 wt% or lower. Specific examples of water-soluble organic solvents include alkyl alcohols having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, SeC-butyl alcohol, and TeT-butyl alcohol. Amides such as dimethylformamide and dimethylacetamide. Ketones or ketoalcohols such as acetone and diacetone alcohol. Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol; or alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; lower alkyl ether acetates such as polyethylene glycol and monomethyl ether acetate; glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether; polyhydric alcohols such as trimethylolpropane and trimethylolethane; N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. The above-mentioned water-soluble organic solvents can be used alone or in mixtures. Furthermore, deionized water is preferably used as the water.The content of the water-soluble organic solvent in the reaction liquid (RCT) is not particularly limited, but in order to give the color inks (C, M, Y, Bk) desired physical properties as needed, surfactants, antifoaming agents, preservatives, antifungal agents, etc. can be added as appropriate in addition to the above-mentioned components.

[0024] In addition, the color inks (C, M, Y, Bk) and reaction liquid (RCT) used in this embodiment all contain surfactants. Surfactants are used as penetrants to improve the ink's permeability into inkjet recording media. The greater the amount of surfactant added, the stronger the ink's surface tension reduction effect, improving the ink's wettability and permeability into recording media. In this embodiment, a small amount of acetylene glycol EO adduct or the like was added as a surfactant to adjust the surface tension of each ink to 30 dYn / cm or less, and the difference in surface tension between the inks to within 2 dYn / cm. More specifically, the surface tension of each ink was adjusted to approximately 28 to 30 dYn / cm. Surface tension measurements were performed using a fully automatic surface tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.). Note that any measuring device capable of measuring the surface tension of the ink is not limited to the above examples.

[0025] Furthermore, the pH of each ink of this embodiment is stable on the alkaline side, with values ​​ranging from 8.5 to 9.5. From the viewpoint of preventing elution and deterioration of components in the recording device or recording head that come into contact with each ink, and a decrease in the solubility of the dispersion resin in the ink, it is preferable that the pH of each ink be 7.0 or more and 10.0 or less. pH was measured using a PH meter model F-52 manufactured by Horiba, Ltd. Note that the measuring device is not limited to the above examples, as long as it can measure the pH of the ink.

[0026] / / Color ink / / For simplicity's sake, of the black ink (Bk), cyan ink (C), magenta ink (M), and yellow ink (Y) used in this embodiment, only the cyan ink (C) and magenta ink (M) will be described in detail below.

[0027] / / Magenta ink / / Preparation of dispersion First, an AB-type block polymer with an acid value of 300 and a number-average molecular weight of 2500 was prepared using benzyl acrylate and methacrylic acid as raw materials by a conventional method. The polymer was then neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 50% by mass aqueous polymer solution.

[0028] 100 g of the polymer solution was mixed with 100 g of CI Pigment Red 122 and 300 g of ion-exchanged water, and the mixture was mechanically stirred for 0.5 hours.

[0029] The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 70 MPA.

[0030] The dispersion thus obtained was then centrifuged (12,000 RPM, 20 minutes) to remove undispersed material, including coarse particles, to obtain a magenta dispersion having a pigment concentration of 10% by mass and a dispersant concentration of 5% by mass.

[0031] Ink preparation The magenta dispersion liquid was used to prepare the ink, and the following components were added to it to achieve the desired concentration. After thoroughly mixing and stirring these components, the mixture was filtered under pressure using a microfilter (manufactured by Fujifilm Corporation) with a pore size of 2.5 μM to prepare a color ink with a pigment concentration of 4% by mass and a dispersant concentration of 2% by mass. 40 parts of the magenta dispersion 2-pyrrolidone 5 parts 2-methyl-1,3-propanediol 15 parts Acetylene glycol EO adduct 0.5 parts Ion-exchanged water (manufactured by Kawaken Fine Chemicals Co., Ltd.) Remaining

[0032] / / Cyan ink / / Preparation of dispersion First, an AB-type block polymer with an acid value of 250 and a number-average molecular weight of 3,000 was prepared using benzyl acrylate and methacrylic acid as raw materials by a conventional method. The polymer was then neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 50% by mass aqueous polymer solution.

[0033] 180 g of the polymer solution, 100 g of CI Pigment Blue 15:3, and 220 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hours.

[0034] The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 70 MPA.

[0035] The dispersion thus obtained was then centrifuged (12,000 RPM, 20 minutes) to remove undispersed material, including coarse particles, to obtain a cyan dispersion having a pigment concentration of 10% by mass and a dispersant concentration of 10% by mass.

[0036] Ink preparation The ink was prepared by adding the following components to the cyan dispersion to achieve the desired concentration: After thoroughly mixing and stirring these components, the mixture was filtered under pressure using a microfilter (manufactured by Fujifilm Corporation) with a pore size of 2.5 μM to prepare a color ink with a pigment concentration of 4% by mass and a dispersant concentration of 2% by mass. 20 parts of the cyan dispersion 2-pyrrolidone 5 parts 2-methyl-1,3-propanediol 15 parts Acetylene glycol EO adduct 0.5 parts Ion-exchanged water (manufactured by Kawaken Fine Chemicals Co., Ltd.) Remaining

[0037] / / Reaction solution / / The reaction liquid used in this embodiment contains a reactive component that reacts with the pigment contained in the ink to aggregate or gel the pigment. Specifically, this reactive component is a component that, when mixed on a recording medium or the like with an ink containing a pigment that is stably dispersed or dissolved in an aqueous medium by the action of ionic groups, can destroy the dispersion stability of the ink. As described above, glutaric acid is used in this embodiment.

[0038] Note that glutaric acid is not necessarily required; in this embodiment, various water-soluble organic acids can be used as the reactive component of the reaction solution. Specific examples of organic acids include oxalic acid, polyacrylic acid, formic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, levulinic acid, succinic acid, glutaric acid, glutamic acid, fumaric acid, citric acid, tartaric acid, and lactic acid. Further specific examples include pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, oxysuccinic acid, and dioxysuccinic acid. The content of the organic acid is preferably 3.0% by mass or more and 90.0% by mass or less, and more preferably 5.0% by mass or more and 70.0% by mass or less, based on the total mass of the composition contained in the reaction solution.

[0039] Ink preparation In this embodiment, as described above, glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the organic acid, and the following components were mixed to prepare a reaction solution. Glutaric acid 3 parts 2-pyrrolidone 5 parts 2-methyl-1,3-propanediol 15 parts Acetylene glycol EO adduct 0.5 parts Ion-exchanged water (manufactured by Kawaken Fine Chemicals Co., Ltd.) Remaining

[0040] <Recording Media> The recording device of this embodiment can use multiple types of recording media from the perspective of fixing characteristics. Recording media that can be used with the recording device of this embodiment include non-absorbent recording media that do not absorb the moisture contained in the ink, poorly absorbent recording media that have low absorbency of the moisture contained in the ink, and inkjet-compatible recording media that have relatively high absorbency of the moisture. Furthermore, because the surface tension of the ink applied to the recording medium varies depending on the surface energy of the recording medium's surface layer, recording media are classified as easily wettable and difficult to wettable. Thus, this embodiment classifies recording media into three types based on absorbency and two types based on wettability. Recording media used in this embodiment include those that have been registered in advance and those that are newly registered after the fixing characteristics are determined in the recording medium determination process described below.

[0041] FIG. 7 is a diagram that schematically illustrates a screen (user interface; UI) that appears on the display of the PC 312 when the user inputs information about the type of recording medium. The example shown in FIG. 7 shows eight existing types of recording media and a newly registered recording medium that has been determined through a determination process. The eight existing types of recording media are "Vinyl Chloride Film," "Vinyl Chloride Banner," "PP Film," "Yupo," "Wallpaper," "Plain Paper," "Glossy Paper," "Art Paper," and "Coated Paper." The newly registered recording media are registered through a determination process described later in FIG. 13 and subsequent figures when the user attempts to use a recording medium that has not yet been registered. FIG. 7 shows "A: Easily Wet / Non-Absorbent Recording Media" as an example of a recording medium that has been registered through the determination process.

[0042] In Figure 7, among the registered recording media, "vinyl chloride film," "vinyl chloride banner," "PP film," and "Yupo" are non-absorbent recording media. These include recording media with a plastic layer formed on the outermost surface of the substrate, recording media without an ink-receiving layer formed on the substrate, and sheets, films, and banners of glass, Yupo, plastic, etc. Examples of the plastic layers include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene. These non-absorbent recording media have excellent water resistance, light resistance, and abrasion resistance, and are generally used for recording images intended for outdoor exhibitions. In addition, "glossy paper," "art paper," and "coated paper" are recording media for inkjet recording that are highly absorbent due to the penetration of moisture contained in ink. Although these recording media are inferior to less absorbent recording media in terms of water resistance, light resistance, and abrasion resistance, they can absorb ink applied to the ink-receiving layer, resulting in excellent color development and high-quality recording. Therefore, these recording media are generally used for recording images intended for indoor exhibitions. Due to their high absorbency, color inks penetrate the recording media before coming into contact with each other, no reaction liquid is required. Furthermore, "plain paper" and "wallpaper" are poorly absorbent recording media that have a surface made of pulp material or a coating layer that absorbs moisture slowly. On poorly absorbent recording media, color inks come into contact with each other before they are absorbed into the recording medium, causing the color inks to bleed. Therefore, poorly absorbent recording media use a reactive liquid to prevent the color inks from bleeding.

[0043] In order to classify recording media into those that are poorly absorbent and those that are non-absorbent, the amount of liquid transferred per unit time, Vt, is used as an index to quantify the "absorbency" of the recording media. One method for measuring the amount of liquid transferred, Vt, is the "Bristow method," which measures the amount of water absorbed in a short period of time immediately after contact with water. In the Bristow method, a certain amount of liquid, V, is placed in a container with a small opening, and the area, wL, of the part where the liquid has transferred is measured while the opening is in contact with the paper surface. This allows the amount of liquid transferred per unit time, Vt, to be calculated using the formula Vt = V / wL.

[0044] Wettability can also be quantified. Figures 8(a) to 8(c) are diagrams for explaining the quantification of the "wettability" of a recording medium. The "contact angle" (θ: Contact AngLe) is known as an index for quantifying "wettability." As shown in Figure 8(a), the "contact angle" is the angle θ formed by the surface of the recording medium P and the tangent of the droplet Ld at the point where the surface intersects with the surface, and the contact angle θ is expressed by Young's formula γ s =γ L cosθ+γ sL FIG. 8(b) shows a recording medium that is easily wetted. A recording medium that is easily wetted is defined as one with a relatively small contact angle θ, and when a liquid such as ink is applied, it wets and spreads. On the other hand, FIG. 8(c) shows a recording medium that is difficult to wet. A recording medium that is difficult to wet is defined as one with a large contact angle θ, and when a liquid such as ink is applied, it does not wet and spread.

[0045] As described above, wettability and absorbency can be quantified, but for example, when a user of a recording device intends to use a recording medium other than the recording medium that has already been registered, it is not practical to take the above-mentioned measures to separately quantify them. Therefore, in this embodiment, as will be described later with reference to Figures 13 to 21, a predetermined pattern is recorded by the recording device to be used, and the optical density is measured by a sensor to determine the wettability and absorbency of the recording medium.

[0046] Figure 9 is a diagram illustrating the classification of recording media according to their "absorbency" and "wettability." Glossy paper, art paper, and coated paper, which are inkjet-compatible recording media, are classified as recording media with relatively high "absorbency." Plain paper and wallpaper are classified as poorly absorbent recording media with relatively low "absorbency." Furthermore, vinyl chloride film, vinyl chloride banner, PP film, and Yupo are classified as non-absorbent recording media. Regarding "wettability," for example, among non-absorbent recording media, vinyl chloride film, vinyl chloride banner, and PP film are classified as recording media with relatively large contact angles that make them difficult to wet and spread. Yupo is classified as a recording medium with a relatively small contact angle that makes them easy to wet and spread.

[0047] <Image processing and recording control> 10 is a flowchart showing the print data generation process (image processing) executed by the printing apparatus of this embodiment, which is executed by the CPU 301 (FIG. 4) in accordance with a control program stored in the ROM 302 (FIG. 4). This process is started when the user issues a print command on the PC 312 (FIG. 4).

[0048] First, in step S1001, the recording device 1 acquires RGB image data input from the PC 312. Next, in step S1002, information regarding the type of recording medium to be used for recording is acquired. In this embodiment, the user selects the recording medium to be used for recording via the UI shown in FIG. 7, and information regarding the type of recording medium selected based on the user's input is acquired. At this time, if there is a recording medium whose wettability or absorbency has been newly determined (for example, "A: wettable / non-absorbent recording medium" in FIG. 7), which will be described later with reference to FIG. 13 and subsequent figures, it is also possible to select that recording medium by registering it.

[0049] Next, in step S1003, recording conditions are set according to the information about the recording medium acquired in step S1002. As will be described in detail later in FIG. 11, for example, if "PP film," "vinyl chloride film," or "vinyl chloride banner" is selected, these are difficult to wet, so in step S1003 recording conditions for a recording medium that is difficult to wet are set. On the other hand, if "Yupo" is selected, these are easy to wet, so in step S1003 recording conditions for a recording medium that is easy to wet are set.

[0050] Next, in step S1004, color processing conversion is performed to convert the image data of values ​​indicated by RGB signals (8-bit 256-value RGB values) into multi-value data corresponding to each ink used for printing. This color conversion process generates multi-value data represented by 8-bit 256-value information that defines the gradation of each ink for each pixel group consisting of multiple pixels. This color conversion process is performed using a lookup table that defines the correspondence between the RGB values ​​before conversion and the values ​​indicated by the C, M, Y, and Bk signals corresponding to each color ink after conversion (C, M, Y, Bk values) and the values ​​indicated by the reaction liquid signal (RCT value). Here, for the reaction liquid, a different lookup table is used depending on the printing conditions set in step S1003. The relationships indicated by this lookup table will be described later with reference to Figures 11 and 12.

[0051] Next, in step S1005, a quantization process is performed to quantize the multi-value data. This quantization process generates quantized data represented by 1-bit binary information that determines whether or not each ink is ejected for each pixel. Note that dithering, error diffusion, or other methods can be used for this quantization.

[0052] Then, in step S1006, a distribution process is performed to distribute the quantized data for each ink to the multiple scans of the multi-pass printing described above with reference to Figures 5 and 6. This distribution process generates print data represented by 1-bit binary information that determines whether or not to eject each ink for each pixel in each of the multiple scans for a unit area on the print medium.

[0053] Although the embodiment in which all of the processes from S1001 to S1006 are executed by the CPU 301 in the recording device 1 has been described, other embodiments are also possible. For example, all of the processes from S1001 to S1006 may be executed by the PC 312. Also, for example, the PC 312 may execute processes up to the color conversion process (S1004), and the recording device 1 may execute processes from the quantization process (S1005) onwards.

[0054] FIG. 11 is a flowchart showing the recording condition setting process carried out in step S1003.

[0055] In this embodiment, first, in step S1101, it is determined whether or not to blow air during printing (air blowing conditions) according to the type of printing medium acquired in step 1002 (FIG. 10).

[0056] If the type of recording medium acquired in step S1002 is, for example, "coated paper" or one registered as a "recording medium that gets wet easily" in the determination process described later with reference to FIG. 13 and subsequent drawings (see FIG. 9), then in step S1102, the blowing of hot air by the blowing unit 10 (FIG. 1) is turned ON. This blowing dries and thickens the ink, making it possible to prevent ink bleeding. On the other hand, if the type of recording medium acquired is, for example, "glossy paper," then the blowing of air is turned OFF in step S1103.

[0057] Furthermore, if the acquired type of recording medium is, for example, "plain paper" or has been registered as a "low-absorbency recording medium" in the determination process (see FIG. 9), then in step S1102, the air blowing by the air blowing unit 10 is turned ON. This prevents the moisture in the ink from being absorbed by the recording medium, thereby preventing deformation (cockling) of the recording medium. On the other hand, if the acquired type of recording medium is, for example, "vinyl chloride banner" or has been registered as a "non-absorbency recording medium" in the determination process (see FIG. 9), then the air blowing by the air blowing unit 10 is turned OFF in step S1103.

[0058] Next, in step S1104, similar to the determination in step S1101 above, a pass mask to be used in multi-pass printing is determined according to the type of recording medium acquired in step S1002, in other words, whether pass mask B has been selected or not. In this specification, determining whether YES or NO is referred to as "determination."

[0059] If the acquired recording medium is, for example, "Yupo," pass mask B is set as the mask to be used in step S1106. This allows the reaction liquid and color ink to be applied in the same scan. On the other hand, if the acquired recording medium is, for example, "vinyl chloride film," pass mask A is set in step S1105. This allows the reaction liquid to be applied to the recording medium in a scan prior to the scan in which the color ink is applied. This makes it possible to cause the color ink and the reaction liquid to react, causing aggregation and preventing bleeding.

[0060] Furthermore, if the acquired type of recording medium is, for example, "wallpaper" or the determination process determines that it is a "low-absorbency recording medium," then pass mask B is set in step S1106. This prevents the reaction liquid from being absorbed by the recording medium and not reacting with the color ink, by applying the reaction liquid and color ink in the same scan. On the other hand, if the acquired type of recording medium is, for example, "PP film" or the determination process determines that it is a "non-absorbency recording medium," then pass mask A is set in step S1105.

[0061] Next, in step S1107, the amount of reaction liquid to be applied is determined in accordance with the type of recording medium acquired in step S1002, similar to the determination in step S1101 above.

[0062] If the acquired recording medium is, for example, a non-absorbent recording medium that is easily wetted, such as "Yupo," then in step S1108 the amount of reactive liquid applied is set to 70%. In this way, for non-absorbent recording media that are easily wetted, increasing the amount of reactive liquid applied can cause the color ink to react and prevent bleeding. In this embodiment, the "amount applied" is expressed as a duty (%), which is the percentage of pixels to which reactive liquid is applied out of the pixels that make up the image.

[0063] Furthermore, if the acquired recording medium is a recording medium that is difficult to wet and non-absorbent, such as a "vinyl chloride film," then in step S1109 the amount of reaction liquid applied is set to 40%.

[0064] Furthermore, if the acquired recording medium is, for example, a recording medium for inkjet recording such as "glossy paper" or poorly absorbent "plain paper," the amount of reaction liquid applied is set to 0% in step S1110.

[0065] The determination of the air blowing, pass mask, and amount of reaction liquid applied in steps S1101, S1104, and S1107 described above is performed according to the combination of wettability and absorbency of the recording medium. Fig. 12 is a diagram showing the relationship between the air blowing ON / OFF, pass mask A / B, and amount of reaction liquid applied for each combination of wettability and absorbency of the recording medium according to this embodiment. Specifically, Fig. 12 shows a table referenced in step S1003 of Fig. 10 (processing of Fig. 11).

[0066] As shown in FIG. 12, the table specifies the amount of reaction liquid to be applied, the ON / OFF state of the air blower, and the mask A / B for each of the recording media already registered in the recording device, such as "vinyl chloride," ..., and "coated paper" (i.e., for each recording medium). Furthermore, for recording media registered through the determination process described later in FIG. 13 and subsequent figures, the amount of reaction liquid to be applied, the ON / OFF state of the air blower, and the mask A / B are also specified for the recording media. For example, as described above in FIG. 7, "A: Easily wettable / non-absorbent recording medium" is a newly registered recording medium that is determined to be easily wettable and non-absorbent. Additionally, parameters related to the above recording conditions can be specified for "B: Less wettable / non-absorbent recording medium," "C: Easily wettable / poorly absorbent recording medium," and "D: Less wettable / poorly absorbent recording medium" as combinations of wettability and absorbency.

[0067] <Determining the fixing characteristics of recording media> In this embodiment, when an unregistered recording medium is used, the ink fixing characteristics of the recording medium are determined, and the recording conditions are set accordingly as described above in Fig. 11. In this embodiment, the ink fixing characteristics of the recording medium are determined by recording a predetermined pattern on the unregistered recording medium that the user intends to use and measuring the optical density of the pattern.

[0068] Fig. 13 is a flowchart showing a process for determining the ink fixing characteristics of a recording medium according to this embodiment and registering the determined fixing characteristic information. The process shown in Fig. 13 is executed when a user intends to use a recording medium that has been pre-registered in the recording device. Specifically, this process is started when the user selects an ink fixing characteristic determination sequence via PC 312 or an operation unit provided on the recording device main body.

[0069] First, in step S1301, the name of the recording medium to be used is input via the operation unit. The recording medium name can be, for example, "A" as shown in FIG. 7, etc. In step S1302, this input recording medium name is registered in a predetermined memory such as a ROM. Next, in step S1303, a process for determining the fixing characteristics of the recording medium is performed, the details of which will be described later in FIG. 17 and FIG. 21. Finally, in step S1304, the fixing characteristics of the recording medium are registered together with the recording medium name. For example, this is registered as "A: wettable / non-absorbent recording medium."

[0070] In this embodiment, the ink fixing characteristics of a recording medium are determined by a combination of the wettability and ink absorbency of the recording medium. In this embodiment, the wettability and absorbency associated with this combination are individually determined for each recording medium to be newly used.

[0071] (Judgment of wettability) FIG. 14 is a diagram illustrating a test pattern printed in a wettability determination according to this embodiment. The test pattern of this embodiment prints a black (Bk) ink pattern and a reaction liquid pattern. This is because, as will be described later with reference to FIG. 15, the behavior of the Bk ink and reaction liquid regarding fixation differs depending on the wettability of the recording medium. The following description of Bk ink also applies to the other color inks (Y, M, C), and in this respect Bk ink will be treated as representative of the color inks.

[0072] As shown in FIG. 14, the test pattern is printed by printing pattern Pt1 using only black ink (zero amount of reactive liquid applied) in one scan of the printhead 4. Pattern Pt2 is printed by overlapping black ink and reactive liquid in one scan of the printhead 4. More specifically, pattern Pt1 is printed by ejecting black ink at a duty of 50% and reactive liquid at a duty of 0% (zero amount applied) onto the 1200 dPi pixels that make up the pattern. Pattern Pt2 is printed by ejecting reactive liquid and black ink, each at a duty of 50%, in that order, onto the 1200 dPi pixels that make up the pattern. Note that in FIG. 15, the reactive liquid is transparent, but the amount applied is indicated by a shade for convenience. In this way, this embodiment prints different black ink and reactive liquid application modes for each pattern. The amount of reaction liquid applied in pattern Pt1 may be substantially zero, and may be applied to an extent that does not affect the determination result.

[0073] Figures 15(a) and (b) are diagrams illustrating the behavior of ink and reaction liquid fixation and the resulting optical density when the pattern shown in Figure 14 is recorded. Figure 15(a) shows an example where a pattern is recorded on a recording medium that is difficult to wet, while Figure 15(b) shows an example where a pattern is recorded on a recording medium that is easy to wet.

[0074] As shown in FIG. 15(a), when a pattern is printed on a recording medium that is difficult to wet, in pattern Pt1 (first pattern) to which no reactive liquid is applied, the applied black inks are difficult to wet, so the black inks come into contact with each other, causing liquid migration. As a result, the coverage of the recording medium surface by the black ink is low. On the other hand, in pattern Pt2 (second pattern) to which reactive liquid is applied, the black ink reacts and aggregates with the reactive liquid that was applied earlier in the same scan, so no liquid migration occurs between the inks. As a result, pattern Pt2 has a relatively higher ink coverage of the recording medium than pattern Pt1, and is detected as having a higher optical density and lower brightness (higher density) than pattern Pt1.

[0075] In contrast, when a pattern is printed on the easily wettable printing medium shown in Figure 15(b), in pattern Pt1, to which no reactive liquid is applied, the Bk inks are easily wetted even when they come into contact with each other, so they spread without causing liquid accumulation. As a result, the coverage of the Bk ink is high, and this is detected as a high optical density. On the other hand, in pattern Pt2, to which reactive liquid is applied, the Bk ink does not spread due to coagulation caused by reaction with the previously applied reactive liquid, so the coverage is lower than that of pattern Pt1, and the optical density is detected as lower than that of pattern Pt1, resulting in a higher brightness (lower density).

[0076] Figures 16(a) and (b) are diagrams showing the brightness described in Figures 15(a) and (b), where Figure 16(a) corresponds to the brightness described in Figure 15(a) and Figure 16(b) corresponds to the brightness described in Figure 15(b).

[0077] As shown in Figure 16(a), when a pattern is recorded on a recording medium that is difficult to wet, the pattern Pt2 to which the reaction liquid has been applied has lower brightness compared to the pattern Pt1 to which the reaction liquid has not been applied. On the other hand, as shown in Figure 16(b), when a pattern is recorded on a recording medium that is easy to wet, the pattern Pt2 to which the reaction liquid has been applied has higher brightness compared to the pattern Pt1 to which the reaction liquid has not been applied.

[0078] As described above, the patterns Pt1 and Pt2 shown in Fig. 14 are printed on a printing medium. Depending on the relative relationship (which is higher) between the optical densities or brightnesses of these patterns (the first density or brightness and the second density or brightness), it is possible to determine whether the wettability of the printing medium on which the patterns are printed is low or high.

[0079] FIG. 17 is a flowchart showing the wettability determination process for a recording medium according to the present embodiment described above.

[0080] First, in step S1601, the test patterns Pt1 and Pt2 for determining wettability, as described above in FIG. 14, are recorded on the recording medium to be determined. Then, in step S1602, the density of the recorded test patterns is measured by optical sensor 2. Next, in step S1603, the brightness is calculated based on the optical density, which is the measurement result of patterns Pt1 and Pt2. Then, in step S1604, it is determined whether the brightness of pattern Pt1 is higher than the brightness of pattern Pt2.

[0081] If the brightness of pattern Pt1 is higher than the brightness of pattern Pt2, then in step S1605 it is determined that the recording medium is difficult to wet, and the recording medium being determined is registered as a recording medium that is difficult to wet. Note that this registration is performed in combination with the absorbency determination result described later in FIG. 21, and the same applies below. On the other hand, if the brightness of pattern Pt1 is not higher than the brightness of pattern Pt2, that is, if the brightness of pattern Pt1 is lower, then in step S1606 it is determined that the recording medium is easy to wet, and the recording medium being determined is registered as a recording medium that is easy to wet. This process ends after steps S1605 and S1606.

[0082] As described above, according to this embodiment, it is possible to determine the wettability of a recording medium, and as a result, even when the wettability differs depending on the brand of recording medium or when using a type of recording medium that has not been registered in advance, it is possible to set recording conditions according to the wettability.

[0083] In the above example, pattern Pt1 is a pattern to which no reaction liquid is applied. However, even a small amount of reaction liquid can result in the same results as described above, i.e., liquid accumulation on a less wettable recording medium and spreading on a more wettable recording medium. Therefore, pattern Pt1 is not limited to a pattern to which no reaction liquid is applied. While the above example describes measuring brightness using an optical sensor, this is not limiting. For example, a user may visually determine the density difference between the patterns and input the determination result via an operation unit. The wettability of the recording medium may also be set. In this case, it is preferable to arrange patterns Pt1 and Pt2 adjacent to each other to make it easier for the user to recognize the density difference. Furthermore, if the brightness difference between patterns Pt1 and Pt2 is within a certain value, the type of recording medium may be determined to be inkjet-compatible paper. The optical sensor may set a threshold value to distinguish between a less wettable recording medium and a more wettable recording medium, taking into account detection value error. In other words, if the detection value error of the optical sensor is within a certain value, the optical sensor determines that pattern Pt1 is dark if the brightness difference between patterns Pt1 and Pt2 is greater than a certain value. When the difference in brightness between the pattern Pt1 and the pattern Pt2 is equal to or less than a certain value, the pattern Pt1 is determined to be light.

[0084] (Assessment of absorbency) 18 is a diagram illustrating the test pattern printed for the absorbency determination according to this embodiment. The test pattern according to this embodiment prints a pattern of black (Bk) ink, which is a representative color ink, and a pattern of the reaction liquid.

[0085] As shown in FIG. 18, pattern Pt3 is a pattern in which black ink and reaction liquid are printed in a superimposed manner during a single scan of the printhead 4. Pattern Pt4 is a pattern in which black ink is ejected during the first scan of the printhead 4, and reaction liquid is ejected during the second scan. More specifically, pattern Pt3 is printed by ejecting black ink and reaction liquid at a duty of 50% onto the 1200 dPi pixels that make up the pattern. Pattern Pt4 is printed by ejecting reaction liquid during the first scan and black ink during the second scan, each at a duty of 50% onto the 1200 dPi pixels that make up the pattern. Note that although the reaction liquid is transparent in FIG. 18, the amount of application is indicated by shades of gray for convenience.

[0086] Figures 19(a) and (b) are diagrams illustrating the behavior of ink and reaction liquid fixation and the resulting optical density when the pattern shown in Figure 18 is recorded. Figure 19(a) shows an example where a pattern is recorded on a non-absorbent recording medium, and Figure 19(b) shows an example where a pattern is recorded on a poorly absorbent recording medium.

[0087] As shown in Figure 19(a), when a pattern is printed on a non-absorbent recording medium, pattern Pt3, in which the reaction liquid and black ink are applied by ejecting them in the same scan, reacts with and coagulates the reaction liquid and black ink immediately after being applied to the recording medium, and the black ink does not wet or spread. Furthermore, pattern Pt4, in which the reaction liquid is applied in the first scan and then the black ink is applied in the second scan, is printed on a non-absorbent recording medium, so the reaction liquid remains on the recording medium before the black ink is applied. Therefore, pattern P4 also reacts with and coagulates the reaction liquid, and the black ink does not wet or spread. As a result, the black ink coverage on the recording medium for patterns Pt3 and P4 is approximately the same. On the other hand, as shown in Figure 19(b), when a pattern is printed on a poorly absorbent recording medium, pattern Pt3, in which the reaction liquid and black ink are applied in the same scan, reacts with and coagulates the reaction liquid, and the black ink does not wet or spread, just like in the case of the non-absorbent recording medium. On the other hand, in pattern Pt4, which is formed by applying the reaction liquid in the first scan and then applying the black ink in the second scan, the reaction liquid applied earlier has penetrated the recording medium, and no reaction liquid remains on the recording medium. Therefore, the black ink does not form agglomerates that can react with the reaction liquid, so the black ink spreads. As a result, the black ink coverage of the recording medium is higher in pattern P4 than in pattern P3.

[0088] In the above explanation, it was explained that in the case of a poorly absorbent recording medium, the pattern Pt4 will wet and spread, but this is not limited to this case. Liquid accumulation may also occur, and whether the reaction liquid spreads or is accumulated depends on the surface free energy that changes as the reaction liquid penetrates the recording medium. As a result, liquid accumulation may occur without wetting and spreading. For this reason, if the density or brightness of the patterns Pt3 and Pt4 are approximately equal, the recording medium is determined to be non-absorbent, and if there is a difference in density or brightness between the patterns Pt3 and Pt4, the recording medium is determined to be poorly absorbent.

[0089] Figures 20(a) and (b) are diagrams showing the brightness described in Figures 19(a) and (b), where Figure 20(a) corresponds to the brightness described in Figure 19(a) and Figure 20(b) corresponds to the brightness described in Figure 19(b).

[0090] As shown in Figure 20(a), among the patterns recorded on a non-absorbent recording medium, pattern Pt3 in which the reaction liquid and black ink are applied in the same scan and pattern Pt4 in which the reaction liquid and black ink are applied in different scans, i.e., with a certain time interval between them, have approximately the same brightness. On the other hand, as shown in Figure 20(b), among the patterns recorded on a poorly absorbent recording medium, pattern Pt3 in which the reaction liquid and black ink are applied in the same scan has a higher brightness than pattern P4 in which the reaction liquid and black ink are applied in different scans, i.e., with a certain time interval between them.

[0091] FIG. 21 is a flowchart showing the absorbency determination process for a recording medium according to the present embodiment described above.

[0092] First, in step S2001, the test patterns Pt3 and Pt4 for judging absorbency, as described above in FIG. 18, are recorded on the recording medium to be judged. Then, in step S2002, the density of the recorded test patterns is detected by optical sensor 2. Next, in step S2003, the brightness is calculated based on the detected density of patterns Pt3 and Pt4. Then, in step S2004, it is determined whether the difference in brightness between patterns Pt3 and Pt4 is within a predetermined value.

[0093] If it is determined in step S2004 that the brightness difference is within the predetermined range, then in step S2005 the recording medium is determined to be non-absorbent and is registered as a "non-absorbent recording medium" (FIG. 12). On the other hand, if it is determined that the brightness difference is not within the predetermined range, then in step S2006 the recording medium is determined to be poorly absorbent and is registered as a "poorly absorbent recording medium" (FIG. 12). Note that the above-mentioned predetermined range is a range in which the brightness of the two patterns is considered to be approximately equal, and the predetermined range can be determined, for example, based on the brightness obtained as a result of recording the above-mentioned patterns on existing registered non-absorbent recording media and poorly absorbent recording media.

[0094] So far, we have described a method for determining wettability and absorbency when recording an image on the front side, which is the first side, of a recording medium. The inventors' research has revealed that, when it is possible to record images on both sides of a recording medium, the wettability and absorbency of the back side, which is the second side, differ depending on whether an image is recorded on the front side and the duty of the image recorded on the front side. Therefore, it is necessary to determine the wettability and absorbency described above in advance for the second side of the recording medium as well.

[0095] 22 is a diagram illustrating a method for determining the wettability and absorbency of the second side of a recording medium when performing double-sided recording. Side 221 is the first side of the recording medium on which an image is recorded first, and side 222 is the second side on which an image is recorded after the first side. On side 221, area 223 is a solid image recorded at a uniform density with a 50% duty, and area 224 is a solid image recorded at a uniform density with a 100% duty. When recording the solid images in areas 222 and 223, the necessary reaction liquid for recording at each duty is also applied.

[0096] The wettability determination pattern and absorbency determination pattern on surface 222 are recorded after areas 223 and 224 on surface 221 are recorded. Area 225 on surface 222 represents the position directly behind area 223 on surface 221, and area 226 on surface 222 represents the position directly behind area 224 on surface 221. A wettability determination pattern 227 and an absorbency determination pattern 228 are recorded in area 225, and a wettability determination pattern and an absorbency determination pattern are similarly recorded in area 226.

[0097] By detecting the wettability determination pattern and absorbency determination pattern recorded on the second side with a sensor or by visually determining them, the wettability and absorbency of the second side can be determined according to the duty of the first side. This makes it possible to determine the wettability and absorbency of the second side even if the fixing characteristics of the second side of a recording medium with an image recorded on the first side differ from the fixing characteristics of the second side when no image is recorded on the first side.

[0098] When no image is recorded on the first side, the fixing characteristics of the second side can be determined by recording a wettability determination pattern and an absorbency determination pattern in the area directly behind the first side where no image is recorded. Also, only one of the wettability determination and the absorbency determination may be performed.

[0099] FIG. 23 is a flowchart for determining the wettability and absorbency when double-sided printing is performed on a printing medium.

[0100] In step S2301, the "wettability determination process" described with reference to FIG. 17 is performed on the first side of the recording medium. In step S2302, the "absorbency determination process" described with reference to FIG. 21 is performed on the first side of the recording medium. Thereafter, in step S2303, a selection is made as to whether or not to perform the determination process on the second side of the recording medium. This selection may be made by accepting input from the user. If "NO" is selected here, the process ends with only the wettability and absorbency determination process on the first side.

[0101] If "YES" is selected in step S2303, a solid image of uniform density is recorded at a predetermined position on the first surface in step S2304. As explained using FIG. 22, this is a solid image of areas 223 and 224 on surface 221, which is the first surface. In FIG. 22, the solid image has areas with a duty of 50% and 100%, but this is not limited to these values ​​and may have one or more. By determining the wettability and absorbency for multiple types of duty, it is possible to determine the wettability and absorbency of the second surface according to the density of the first surface.

[0102] After the solid image has been printed in step S2304, the printing medium is removed in step S2305, turned over, and then set back on the other side. Then, in step S2306, the wettability determination process for the second side is performed, and in step S2307, the absorbency determination process for the second side is performed. Here, as described with reference to FIG. 22, a wettability detection pattern is printed in area 225, which is directly behind area 223, and an absorbency detection pattern is printed in area 226, which is directly behind area 224. Then, the wettability and absorbency are determined by detecting the density of the pattern with a sensor or by receiving the results of a user's visual inspection, and the results are stored, and the process ends.

[0103] The flowchart shown in Fig. 23 explains the flow for selecting whether to perform the determination process for the second surface after performing the wettability determination process and the absorbency determination process for the first surface. Fig. 24 is a flowchart of the process for selecting whether to first perform the determination process for the second surface.

[0104] As described above, this embodiment makes it possible to determine whether an unregistered recording medium used for recording has non-absorbency or poor absorbency. This makes it possible to set recording conditions according to the non-absorbency or poor absorbency of the recording medium, even when the absorbency varies depending on the brand of recording medium or when using a type of recording medium that has not been registered in advance. Furthermore, when performing double-sided recording, it is possible to determine the wettability and absorbency of the second side, on which an image is recorded after the first side, on which an image is recorded first. Furthermore, by determining the wettability and absorbency of the second side for each duty of the image recorded on the first side, the accuracy of control using the determination results can be improved.

[0105] In this embodiment, instead of detecting the density difference with an optical densitometer, the user may visually check the density difference and determine whether the pattern is non-absorbent or poorly absorbent. Similarly, in this case, it is desirable that patterns Pt3 and Pt4 are adjacent to each other so that the user can easily recognize the density difference.

[0106] The above-described embodiment relates to a serial scan printing apparatus that prints by alternating print head scanning and print medium transport. However, the technology disclosed herein can also be applied to a full line printing apparatus that prints by transporting the print medium without scanning the print head, by printing patterns Pt1, Pt2, Pt3, and Pt4. In this case, pattern Pt4 can be implemented by applying the reaction liquid and Bk ink after a predetermined delay in the transport of the print medium, which is equivalent to one scan of the reaction liquid and Bk ink.

[0107] As described above, the ink fixing characteristics to be determined are a combination of wettability and absorbency, but the application of the present disclosure is not limited to this. For example, the ink fixing characteristics may be either the wettability or absorbency of the recording medium. In this regard, in the present disclosure, at least one of wettability and absorbency is determined. [Explanation of symbols]

[0108] 2 Optical Sensor 3 Conveyor roller pair 4 recording head 5 Carriage 6 Platen 300 control section 301 CPU

Claims

1. a recording means for recording an image by applying ink containing a coloring material and a reaction liquid not containing a coloring material onto a recording medium, the recording means recording a test pattern including a first pattern and a second pattern in which the application mode of the ink and the reaction liquid differs from that of the first pattern, on a second surface, which is the reverse side of the first surface, of the recording medium on which a pattern of a uniform predetermined density is recorded using the ink in a predetermined region of the first surface, at a position corresponding to the predetermined region; an acquiring means for acquiring information regarding a first density of the first pattern and a second density of the second pattern; a determining means for determining, based on the information, the fixing characteristics at a position corresponding to a predetermined area on a second surface of a recording medium on which an image of a predetermined density has been recorded in the predetermined area on the first surface; A recording device comprising:

2. 2. The recording apparatus according to claim 1, wherein the fixing characteristics of the recording medium are at least one of wettability and absorbency of the recording medium with respect to the ink.

3. 2. The recording apparatus according to claim 1, wherein the application mode is an amount of the reaction liquid applied relative to an amount of the ink applied.

4. 2. The recording apparatus according to claim 1, wherein the amount of the reaction liquid applied to the second pattern is greater than the amount of the reaction liquid applied to the first pattern.

5. 5. The recording apparatus according to claim 4, wherein the amount of the reaction liquid applied in the first pattern is substantially zero.

6. 2. The recording apparatus according to claim 1, wherein the second pattern is formed by applying the ink after applying the reaction liquid.

7. 2. The recording apparatus according to claim 1, wherein the application mode is a time period from when the reaction liquid is applied to when the ink is applied.

8. the ink and the reaction liquid are ejected from the recording means during scanning by the recording means, the first pattern is formed by applying the reaction liquid and the ink in this order during one scan of the recording means; 8. The printing apparatus according to claim 7, wherein the second pattern is formed by applying the reaction liquid in one scan of the printing means, and applying the ink in a scan subsequent to the scan.

9. 3. The recording device according to claim 2, wherein if the information indicates that the first density is higher than the second density, the recording medium is determined to be easily wet, and if the information indicates that the first density is lower than the second density, the recording medium is determined to be difficult to wet.

10. The recording device described in claim 7, characterized in that if the information indicates that the difference between the first density and the second density is within a predetermined range, it is determined to be a non-absorbent recording medium, and if the information indicates that the difference between the first density and the second density is not within the predetermined range, it is determined to be a poorly absorbent recording medium.

11. 2. The recording apparatus according to claim 1, wherein the first pattern and the second pattern are recorded adjacent to each other.

12. 2. The recording apparatus according to claim 1, wherein the information is acquired by an optical sensor.

13. 2. The recording apparatus according to claim 1, further comprising a setting unit that sets recording conditions based on the result of the determination by the determination unit.

14. 14. The recording apparatus according to claim 13, wherein the setting unit sets, as the recording conditions, air blowing conditions of an air blowing unit that blows air from the recording unit toward a portion onto the recording medium where the ink and the reaction liquid are ejected.

15. 14. The printing apparatus according to claim 13, wherein the setting means sets, as the printing condition, an order in a scan in which the ink and the reaction liquid are ejected from the printing means.

16. 14. The recording apparatus according to claim 13, wherein the setting means sets, as the recording condition, an amount of the reaction liquid to be applied to the recording medium, the amount being ejected from the recording means.

17. 2. The recording apparatus according to claim 1, wherein the reaction liquid contains a component that aggregates the coloring material.

18. the recording means records a plurality of patterns having different ink densities on the first surface, and records a plurality of test patterns on the second surface at positions corresponding to the plurality of patterns, the acquiring means acquires the information for each of the plurality of test patterns; 2. The recording apparatus according to claim 1, wherein the determining unit determines the fixing characteristics for each density of the plurality of test patterns.

19. A control method for a recording device including a recording means that records an image by applying ink containing a colorant and a reaction liquid that does not contain a colorant onto a recording medium, and that records a test pattern including a first pattern and a second pattern in which the ink and the reaction liquid are applied in a different manner from the first pattern, on a second surface, which is the reverse side of the first surface, of the recording medium on which a pattern of a uniform predetermined density is recorded in a predetermined area of ​​the first surface, the test pattern including the first pattern and a second pattern in which the ink and the reaction liquid are applied in a different manner from the first pattern, obtaining information about a first concentration of the first pattern and a second concentration of the second pattern; a step of determining, based on the information, a fixing characteristic at a position on a second surface of a recording medium on which an image of a predetermined density has been recorded in a predetermined area of ​​the first surface, the position corresponding to the predetermined area; A control method comprising:

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