JP2012035422A - Ink jet recorder and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a uniform glossiness over the entire recording area and perform recording free from a connection stripe in an ink jet recorder.SOLUTION: In a recording step 901, multi-path recording is carried out using a nozzle array 502. At this time, nozzle arrays 503 and 504 are not used. After the recording step is finished, a first application step 902 for clear ink through multi-path recording is carried out using the nozzle array 503. Subsequently, after the application of clear ink in the first application step 902 is finished, scanning is carried out one time using the nozzle array 504 and a second application step 903 for the clear ink is carried out. Thus, while the flatness of the surface of the liquid film of the clear ink is maintained, fixing is carried out, and high glossiness can be obtained. Additionally, since the permeation speed decreases due to the clear ink applied in the first application step, as described above, liquid films between the scanning areas are also integrated. As a result, recesses and projections can be decreased in a portion connecting the scanning areas.

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method, and more particularly to a technique for improving the gloss of a recorded material by applying a clear ink to the recorded material using ink.

  As a technique for imparting gloss to an ink jet recorded image, Patent Document 1 discloses that the glossiness of the entire recording area is made uniform by varying the amount of clear ink applied according to the amount of ink applied. Are listed. Specifically, the clear ink application amount is decreased in a region where the ink application amount is large, and the clear ink application amount is increased in a region where the ink application amount is small. Thereby, for example, clear ink is also applied to a non-image area to which no ink is applied, and glossiness is made uniform throughout the recording area including such a non-image area.

JP 2006-272934 A JP 2005-297212 A

  However, even if the technique described in Patent Document 1 is adopted, it may be difficult to achieve uniform glossiness over the entire recording area including the image area and the non-image area.

  According to the method described in Patent Document 1, since clear ink is applied to a non-image area, it is possible to expect an improvement in glossiness of the entire recording area. However, on the surface of the recording medium, the permeation state of the clear ink applied thereafter differs between the area where ink is applied and the area where ink is not applied. For this reason, even if it is intended to smooth the unevenness formed by the ink color material on the surface of the recording medium with clear ink, smoothing may be insufficient due to the difference in permeation state for each of the above areas, improving glossiness May not be possible.

  Here, as a method for applying the clear ink, there is a so-called multi-pass method as in the ink application. However, in Patent Document 2, glossiness may be impaired when clear ink is applied by a multi-pass method. Therefore, when a recording medium with high glossiness is used, recording is performed with as few passes as possible. Proposed. On the other hand, when clear ink is applied by a single scan without adopting the multi-pass method, glossiness is easily obtained, but ink and clear ink at the junction of the scan area due to a conveyance amount error of the recording medium. Concavities and convexities may be formed. Such irregularities are finally recognized as streak-like unevenness (hereinafter referred to as connecting stripes) in the recorded image and impair the image quality.

  An object of the present invention is to provide an ink jet recording apparatus and an ink jet recording method capable of performing recording with uniform gloss over the entire recording area and without occurrence of a connecting stripe.

  In order to achieve the above object, in the present invention, the main scanning for scanning the recording medium using the recording head for ejecting the ink and the clear ink for increasing the glossiness of the recorded matter by the ink and the auxiliary scanning for conveying the recording medium are performed. An inkjet recording apparatus that performs recording by ejecting ink or clear ink from the recording head during the main scanning, and records the image by ejecting ink from the recording head and applying ink to the recording medium A recording process, and a plurality of times of main scanning using a recording head with respect to an area including the area where the image of the recording medium is recorded, and clear ink is ejected from the recording head in the plurality of times of main scanning. A first application step of applying a clear ink to the recording head, and a recording head at least after the first application step to a region to which the clear ink has been applied in the first application step. And a second application step of performing a single main scan used and discharging a clear ink from the recording head and applying the clear ink to the recording medium in the one main scan. It is characterized by.

  According to the above configuration, it is possible to perform recording with uniform gloss over the entire recording area and without occurrence of a connecting stripe.

FIG. 6 is a schematic diagram for explaining a fixing state of ink and clear ink applied by a recording method according to an embodiment of the present invention. (A) And (b) is a schematic diagram which shows a fixing state when clear ink is applied in one pass in both the first application step and the second application step described above with reference to FIG. . It is a perspective view which shows the outline | summary of the serial type inkjet recording device which concerns on one Embodiment which can perform the recording method of this embodiment demonstrated in FIG. FIG. 4 is a block diagram illustrating a control system of the ink jet recording apparatus illustrated in FIG. 3. (A) is the schematic which looked at the recording head of this embodiment from the discharge port formation surface, (b) is this 2nd method about the recording head of this embodiment shown to Fig.5 (a). It is a figure for demonstrating. (A) is a figure for demonstrating this 3rd method about the recording head of this embodiment shown to Fig.5 (a), (b) is FIG.5 (b) and FIG.6 (a). FIG. 6 is a diagram showing another form of the recording head shown in FIG. It is a flowchart which shows the recording procedure by the 1st recording method which concerns on embodiment of this invention. It is a flowchart which shows the recording procedure by the 2nd recording method which concerns on embodiment of this invention. It is a flowchart which shows the recording procedure by the 3rd recording method which concerns on embodiment of this invention.

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

  Embodiments of the present invention record images using pigment ink and clear ink. The pigment ink is a color ink containing a colored pigment, and may be monocolor, but a plurality of types such as cyan, magenta, yellow, and black can be used. Further, if necessary, it can be used in combination with light-colored inks having different densities or special color inks such as red, green, and blue. As the clear ink, a substantially colorless ink in which a water-soluble resin or a water-soluble emulsion is dissolved in water and an organic solvent and a surfactant are contained is used.

  In the recording control of the present embodiment, an image is recorded with the pigment ink using a serial type ink jet recording apparatus, and then the clear ink is applied in two stages. In the first clear ink application step, multi-pass printing is executed, and in the second clear ink application step, single pass, that is, one-pass printing is executed to complete the clear ink application. Here, multi-pass printing is a printing method in which an image is formed stepwise by performing a plurality of scans on an area having a width d that can be printed by one scan using a print head. The number of scans for completing the recording is referred to as the number of passes, the multi-pass recording refers to recording of two or more passes, and the one-pass recording completes recording in one scan.

  The first clear ink application step (hereinafter also simply referred to as “first application step”) penetrates the clear ink applied in the second clear ink application step (hereinafter also simply referred to as “second application step”). Plays a role in controlling speed. That is, in the first application process, it is desirable to apply clear ink without any gap. If there is a gap, the penetration speed of the clear ink applied in the second application step will be different between the gap and other parts, and the purpose of making the penetration speed uniform will not be achieved. However, “with no gap” as used herein is allowed to have a small gap. Specifically, there is no problem as long as the clear ink resin covers an area of 80% or more substantially evenly with respect to the area on which the gloss of the recorded material surface is desired. “Substantially equal” means a state in which there is no significant deviation in the gap distribution. In the present embodiment, the standard deviation σ of coverage measurement at 10 locations is 10% or less. An optical microscope is used to measure the coverage of the clear ink resin. First, the recorded matter after applying the clear ink in the first application step is photographed with an optical microscope. In this measurement, an image made infinite by an optical microscope with a 10 × objective lens was taken using a digital camera with 1.2 million pixels. Olympus BX60M was used for the optical microscope, and Optronics MAGNAFIRE (MODEL 60800) was used for the digital camera. In the portion covered with the clear ink, since the thin film of the clear ink resin is deposited, the color appears to change due to the thin film interference. Next, the color that has changed due to the thin film interference and the color that has not changed are divided into two regions by image processing software or the like, and the area of each region is calculated to obtain the coverage of the clear ink resin.

  The second application step forms a smooth layer with clear ink by one-pass recording and improves the gloss of the finally completed image.

  FIG. 1 is a schematic diagram for explaining a fixing state of ink and clear ink applied by the recording method of the present embodiment described above. The clear ink 103 is applied to the image recorded with the pigment ink 102 on the recording medium 101 by multipass recording in the first application step. In multi-pass printing, a small number of droplets of the clear ink 103 are applied at a low density. Thereby, a plurality of small liquid films are formed by these clear ink droplets 103, but they do not contact each other. Therefore, in such a small liquid film, the ratio of the surface area to the volume is increased, and evaporation into the air is promoted. As a result, a solidified lump is formed in which the resin solid content contained in the clear ink remains on the surface of the recording medium.

  Thereafter, by applying a small number of droplets 103 again at the next scanning, new solidified lumps are stacked and unevenness due to the resin is formed on the surface, so that the glossiness is easily lost. Although glossiness does not improve at this stage, characteristics such as the permeation speed of the clear ink in the second application step are made substantially uniform throughout the image by forming the resin on the recording medium and different pigment inks. In addition, the penetration speed of the clear ink applied in the second application process when the resin of the clear ink 103 blocks the pores of the recording medium and the pigment ink is lower than that for the recording medium and the pigment ink.

  In the recording method of this embodiment, next, in the second application step, clear ink is applied by a one-pass recording method. In one-pass recording, a large number of clear ink droplets are applied at one time, whereby the individual droplets contact and combine to form a large liquid film 104 of clear ink. And it can fix, maintaining the flatness of the liquid film surface of clear ink, and can obtain high glossiness. Further, as described above, since the permeation speed is reduced by the clear ink applied in the first application step, the liquid films between the scanning regions are also integrated. As a result, it is possible to reduce unevenness at the connecting portion between the scanning regions.

  FIGS. 2A and 2B are schematic diagrams showing a fixing state when clear ink is applied in one pass in both the first application step and the second application step, according to a comparative example. A record of the connection between the areas is shown.

  Among these, FIG. 2A shows a case where the liquid films of the clear ink 103 are not integrated at the connecting portion in the first application step. As shown in FIG. 2 (a), when the liquid films of the clear ink 103 are not integrated in the joint portion, the permeation speed is relatively high in the joint portion where the clear ink liquid film does not exist. . Then, the clear ink 104 applied in the second application step flows into the joint portion where the permeation speed is relatively fast, and forms a convex shape.

  On the other hand, FIG. 2B shows a case where, in the first application step, the clear ink 103 is applied so as to overlap each other in the two scanning regions having the boundary as a boundary in the connection part. In this case, since the permeation speed with respect to the already applied pigment ink 102 is high, the liquid films of the overlapped clear ink 103 are not integrated but a convex shape is formed. Next, when the clear ink 104 is applied in the second application step, the permeation speed is suppressed by the clear ink 103 applied in the first application step, so that the liquid films in the two scanning regions are integrated. To do. As a result, fixing is performed so as to keep the shape formed by the clear ink 103 applied in the first application step.

  As described above, when both the first application process and the second application process apply clear ink in one pass, a connecting stripe is likely to occur.

  FIG. 2C is a schematic diagram showing a fixing state when the first application process is performed by 1-pass recording and the second application process is performed by multi-pass recording, similarly to the comparative example. In this example, since a small amount of liquid droplets is fixed according to the shape of the clear ink 103 applied in one-pass recording, the connecting stripe is not improved, and glossiness is caused by the unevenness of the clear ink 104 applied in the second application step. Also decreases.

  FIG. 3 is a perspective view showing an outline of a serial type ink jet recording apparatus according to an embodiment capable of executing the recording method of the embodiment described above. The recording medium P is fed to a nip portion between a conveyance roller 301 arranged on the conveyance path and a pinch roller 302 driven by the automatic sheet feeding unit (not shown) using a sheet feeding motor as a drive source. Then, it is intermittently conveyed in the sub-scanning direction in the figure by the rotation of the conveying roller 301. The platen 303 is provided at a recording position opposite to the surface (discharge surface) on which the discharge ports of the recording head 304 are formed, and supports the recording medium P from the back surface side to Keep the distance of constant. The recording medium P on which recording has been performed on the platen 303 is sandwiched between a rotating discharge roller 305 and a pinch roller 306 which is a rotating body driven by the rotation, and is conveyed in the sub-scanning direction. It is discharged to the paper tray.

  A recording head (not shown) and an ink tank 304 containing ink supplied to the recording head are detachably mounted on the carriage 308. The recording head is mounted on the carriage 308 in a posture in which the ejection port surface faces the recording medium P on the platen 303. The carriage 308 reciprocates in the main scanning direction along the two guide rails 309 and 310 by the driving force of the carriage motor, and in the course of the movement, the recording head performs an ink ejection operation according to the recording signal. An image is formed on the recording medium P by alternately repeating the scanning of the carriage 308 and the recording head and the conveying operation of the recording medium.

  FIG. 4 is a block diagram showing a control system of the ink jet recording apparatus shown in FIG. In the figure, reference numeral 41 denotes an image data input unit, which inputs image data input from a scanner, a digital camera, or the like, or image data stored in a hard disk of a personal computer or the like. In the present invention, here, gloss level data indicating the position on the image and the gloss level (binary data indicating whether or not high gloss is applied) is also input. There are mainly two methods for inputting glossiness data. One is a method in which a user creates glossiness data together with image data and inputs it to an image data input unit. The other is that the user selects normal gloss or high gloss as the image quality, and when high gloss is selected, data that makes the entire surface of the image high gloss is input to the image data input unit as gloss data. Is the method. In this case, when normal gloss is selected, data prepared in advance that the entire image is not made high gloss is input to the image data input unit as glossiness data. Reference numeral 42 denotes an operation unit, and this operation unit includes various keys for the operator to instruct setting of various parameters, start of recording, and the like. Reference numeral 43 denotes a CPU which is a central processing unit, and this CPU controls the entire recording apparatus according to a program stored in the storage medium 44. As the storage medium 44, ROM, FD, CD-ROM, HD, memory card, magneto-optical disk, or the like can be used. The storage contents stored in the storage medium 44 include information 44a regarding the type of recording medium and information 44b regarding ink. Also included is information 44c regarding the presence and position of defective nozzles, information 44d regarding the environment such as temperature and humidity during recording, and various control programs 44e. Reference numeral 45 denotes a RAM. The RAM 45 is used as a work area when executing various programs stored in the storage medium 44 and as a temporary save area for required data during error processing. The above-described gloss data indicating whether or not the entire surface of the image is made highly glossy is also stored here.

  Reference numeral 46 denotes an image data processing unit. The image data processing unit 46 converts the multi-valued image data input from the image data input unit 41 into lower-level discharge data that can be recorded by the recording head. Execute the conversion process. For example, when the data input from the image data input unit 41 is multi-valued image data expressed by 8 bits (256 gradations) × 3 colors (RGB), the image data processing unit 46 first executes this. Is divided into four (C, M, Y, Bk) grayscale data. Next, based on the divided gray scale data of each color, it is converted into dot arrangement data that can be recorded by the corresponding recording head. Here, when the recording head can record only with the two information of ejection and non-ejection, the data is converted into binary according to the pattern defined for either recording or non-recording. If the recording head can control the discharge amount in a plurality of stages, the data value is reduced to the number of stages that can be recorded. At this time, as an applied color reduction method, for example, an error diffusion method can be used. With respect to the glossiness data, the data is converted from the position on the image and binary data indicating whether or not the glossiness is high into dot arrangement data that can be recorded by the corresponding recording head. The conversion means is the same as that of the image data. However, in the high gloss portion, as described above, the clear ink application amount covers the area of 80% or more with respect to the area where the gloss is desired as described above. The dot arrangement data is created so that The dot arrangement is not set for the portion not made high gloss.

  In the above configuration, when multi-pass printing is performed using a serial type ink jet printing apparatus, or when the print head has a plurality of nozzle rows of the same color, the image data processing unit 46 performs further image division. That is, in the case of multi-pass printing, the discharge is distributed to a plurality of printing scans, and in the case of having a plurality of discharge ports, the discharge is distributed to the discharge port array. As the method, there are a method of dividing the grayscale data into more (low density) data, a method of integrating a mask determined for each pass or nozzle row with respect to the dot arrangement data, and the like. is there.

  Reference numeral 47 denotes an image recording unit that outputs an image. A pulse for driving the recording head is generated in accordance with the ejection pattern created by the image data processing unit 46, and ink is ejected from the ejection port of the recording head. Reference numeral 48 denotes a bus for transferring various data, and this bus transmits address signals, data, control signals, and the like in the recording apparatus.

  FIG. 5A is a schematic view of the recording head of this embodiment as viewed from the ejection port formation surface. In the figure, reference numeral 502 denotes a nozzle array for ejecting pigment ink containing pigments such as cyan (C), magenta (M), yellow (Y), and black (Bk), and reference numerals 503 and 504 denote achromatic colors. The nozzle row for discharging substantially transparent clear ink is shown. The width in the sub-scanning direction of each nozzle row is d, and this makes it possible to record a scanning area having a width d on the recording medium in one scan. In each nozzle row, nozzles (ejection ports) 501 for ejecting each ink or clear ink as droplets are arranged at a predetermined pitch in the sub-scanning direction.

  In the present embodiment, a recording mode in which clear ink is applied and a recording mode in which clear ink is not applied can be selectively executed. The user selects a mode in which clear ink is applied when high gloss is desired, but can select a mode in which clear ink is not applied when high gloss is not particularly required.

  In the mode in which the clear ink is not applied, the nozzle row 502 for discharging the pigment ink is used in the recording head shown in FIG. 5A, and the nozzle rows 503 and 504 for discharging the clear ink are not used. In this mode, multi-pass printing is performed using the nozzle row 502. On the other hand, in the mode in which clear ink is applied, the following recording method is executed. There are three recording methods, which will be described in order below.

  The first method is to perform clear ink application in the first application process after completion of the recording process, and sequentially perform clear ink application in the second application process after completion of the recording process.

  FIG. 7 is a flowchart showing a recording procedure according to the first method. First, in the recording step 901, multi-pass recording is performed using the nozzle row 502. At this time, the nozzle rows 503 and 504 are not used. After the recording process is completed, the first application process 902 is performed using the nozzle row 503 while the discharge roller 305 is rotated in the reverse direction and the recording medium P is conveyed in the direction opposite to the sub-scanning direction. That is, scanning is performed a plurality of times for each unit area in which printing is completed by this multi-pass printing in the printing area including the area printed in the printing step 901 using the nozzle row 503. Then, during each of these scans, clear ink is ejected from the nozzle row 503 in accordance with a recording signal to apply clear ink. Next, after the clear ink application in the first application process 902 is completed, the second application process 903 is performed using the nozzle row 504 while the recording medium P is conveyed in the sub-scanning direction by the conveyance roller 301. That is, each of the areas recorded in the first applying step 902 is scanned once using the nozzle row 504, and clear ink is ejected from the nozzle row 504 in accordance with the recording signal during each of these scans. Apply clear ink. This process completes the recorded matter.

  In the above example, the clear ink of the first application process is applied while the recording medium P is conveyed in the direction opposite to the sub-scanning direction. However, after the recording process is completed, the recording medium P is fed again in the sub-scanning direction. Clear ink may be applied by a normal recording method for conveyance. Further, the ejection amounts of the nozzle rows 503 and 504 for ejecting the clear ink need not be the same as those for recording the pigment ink 502 and may be appropriately changed. In particular, in the application of clear ink in the second application process, it is desirable that the liquid films formed at each recording scan come into contact with each other and be integrated. Further, it is not necessary to use a single nozzle row, and in order to secure a discharge amount sufficient to form a liquid film, a plurality of nozzle rows may be used simultaneously to apply clear ink.

  In the second method, the clear ink application in the recording process and the first application process is completed during one transport of the recording medium in the sub-scanning direction, and the clear ink application in the second application process is performed after the completion. Is. FIG. 5B is a diagram for explaining the second method for the recording head of the present embodiment shown in FIG. FIG. 8 is a flowchart showing a recording procedure according to the second method. The second method will be described with reference to FIG. 5B and FIG.

  In FIG. 8, in step 1001, when multi-pass is recorded by a plurality of recording scans with the same scanning speed of the recording head, a recording process using pigment ink is performed by a predetermined number of recording scans, and the predetermined number of recordings is performed. After the scanning, the application step of the first application step of clear ink is performed. For example, the recording head performs 16-pass multi-pass printing, and among these, the 1st to 8th scans for the same image area are assigned to the printing process using pigment ink, and the 9th to 16th scans are assigned to the clear ink in the first application process. Assign to the grant process. When performing 16-pass multi-pass printing, each nozzle array used is divided into first to sixteenth blocks as shown in FIG. 5B. Each time one scan is performed, the sheet is conveyed by d / 16 in the sub-scanning direction. As a result, the first to eighth scans using the first to eighth blocks of the nozzle 602 and the ninth to sixteenth blocks of the nozzle 603 are applied to the same image area having the width of d / 16 on the recording medium. Images are recorded by the 9th to 16th scans using. Thereafter, the discharge roller 305 is rotated in the reverse direction, and clear ink is applied in the second application step 1002 using the nozzle row 604 while conveying the recording medium P in the direction opposite to the sub-scanning direction. That is, each region using the nozzle row 604 is scanned once and clear ink is ejected over the entire region. This completes the recorded matter. The clear ink in the second application process was applied while transporting the recording medium P in the direction opposite to the sub-scanning direction. However, after the recording process is completed, the recording medium P is fed again and transported in the sub-scanning direction. Needless to say, clear ink may be applied.

  In the third method, the clear ink application in the recording process and the first application process and the clear ink application in the second application process are performed during one recording medium conveyance in the sub-scanning direction. FIG. 6A is a diagram for explaining the third method for the recording head of the present embodiment shown in FIG. FIG. 9 is a flowchart showing a recording procedure according to the third method. The third method will be described with reference to FIG. 6 (a) and FIG.

  In this method, when printing a multi-pass by a plurality of scans, a printing process 1101 with pigment ink is performed by a predetermined number of scans, and a first application process 1102 of clear ink is performed after the predetermined number of scans. The second clear ink application step is performed during the recording scan. Specifically, for example, 17-pass multi-pass printing is executed, and among these, the first to eighth scans for the same image area are assigned to the printing process using pigment ink. Further, the 9th to 16th scans are assigned to the clear ink application process of the first application process, and the 17th scan is assigned to the clear ink application process of the second application process. In the case of 17-pass multi-pass printing, each nozzle row is divided into first to 17th blocks as shown in FIG. Each time one scan is performed, the sheet is transported by d / 17 in the sub-scanning direction. As a result, the first to eighth scans using the first to eighth blocks of the nozzle 702 and the ninth to sixteenth blocks of the nozzle 703 are applied to the same image area of the recording medium having the width of d / 17. The 9th to 16th scans used are performed, and the 17th scan using the 17th block of the nozzle 704 is performed to record an image. At the same time as the conveyance of the recording medium P is completed, the recorded matter is completed.

  In the second and third methods having the step of discharging the pigment ink and the clear ink simultaneously, as shown in FIG. 6B, the nozzle row 802 for discharging the pigment ink and the nozzle for discharging the clear ink are used. A recording head in which the columns 803 and 804 are shifted in the sub-scanning direction can also be used. In this method, even if the pigment ink and the clear ink are ejected simultaneously, the recording does not overlap in one scan, and the clear ink is applied in at least one scan after the pigment ink is applied to the same image area. Head. According to this method, waste is eliminated because there is no nozzle that is not involved in ejection.

  In the recording method described above, the case where the first application process and the second application process use different nozzle arrays has been described, but the first application process and the second application process may use the same nozzle array. . In the above description, the conveyance amount in the sub-scanning direction is d / M when the number M of multi-passes is M with respect to the width d of the nozzle row in the sub-scanning direction. May be set to a conveyance width smaller than d / M. As a result, the clear ink can be covered over the entire width that is greater than or equal to the amount of sub-scanning, and in the second application step, the liquid film applied during each scan can be applied so as to overlap.

  Further, the embodiment described above relates to an example using a combination of pigment ink and a liquid (clear ink) for increasing the glossiness of a recorded matter by this ink, but is not limited to this example. Of course. For example, it is apparent from the above description that the present invention can be applied to an example using a combination of a dye ink and a liquid (clear ink) for increasing the glossiness of a recorded matter using the ink.

(Example)
Hereinafter, the effect on the connecting stripe in the application of the clear ink for the purpose of improving the glossiness of the recorded matter according to the example based on the configuration according to the embodiment will be described.

  First, two types of clear inks were prepared with the following composition and then adjusted so that the pH was 9 with an aqueous potassium hydroxide solution.

Clear ink A
・ Styrene acrylic acid resin (acid value 78) 5 parts ・ 1,2-hexanediol 15 parts ・ Surfactant (BYK333) 1 part ・ Pure water remaining Clear ink B
・ Styrene acrylic acid resin (acid value 140) 5 parts ・ Glycerin 7.5 parts ・ Surfactant (BYK333) 5 parts ・ Surfactant (acetylene E100) 1 part ・ Pure water remaining

  As the pigment ink, PFI-101C (hereinafter, cyan), PFI-101M (hereinafter, magenta), PFI-101Y (hereinafter, yellow), and PFI-103BK (hereinafter, black) manufactured by Canon Inc. were used. As the recording apparatus, Canon Inc. inkjet printer F900 was used, and the resolution during recording was set to 1200 dpi (dots / inch) in the sub-scanning direction and 1200 dpi in the main scanning direction. Further, Canon's LFM-GP101R was used as the recording medium. The volume per drop of ink is 4.8 picoliters.

  An image using the pigment ink was recorded with a single color of black, cyan, yellow, and magenta at a duty of 150%. As secondary colors, red (yellow + magenta), green (cyan + yellow), and blue (cyan + magenta) were recorded with a duty of 240% (each color 120% duty). The evaluation patch was a 2 cm square.

  The following two methods were examined for glossiness evaluation. The specular gloss was GMX-203 manufactured by Murakami Color Research Laboratory Co., Ltd., and the 20 ° gloss value was defined as the specular gloss. A higher 20 degree gloss value means higher specular gloss.

  Regarding the image clarity, DIAS DOI Image Analysis System manufactured by QEA was used, and the measured sharpness value was used as the image clarity value. The sharpness value is defined as follows. A white LED is used as a light source, there is a knife edge between the light source and the measurement sample, and a reflection image of the knife edge reflected on the sample is taken with a CCD camera (300,000 pixels: 5 μm per pixel). The pixel field of view is 2.4 mm square. The luminance distribution at the knife edge portion of the reflected image is first-order differentiated, and the reciprocal of the half width is defined as the sharpness value. Therefore, as the sharpness value is larger, a sharper reflected image is obtained, which means that the image clarity is higher.

Further, the connecting stripes were visually evaluated according to the following criteria after drying for 1 hour after applying clear ink.
(Double-circle): A connecting stripe is not visually recognized with all pigment ink colors.
○: Joining streaks are observed for some colors, but practical level ×: Joining streaks are observed for all pigment ink colors.

  Examples are shown below. Table 1 shows the recorded matter recorded only with pigment ink, the results of glossiness and image clarity, which are indicators of glossiness in each example, and the visual evaluation results of the connecting stripes. In Table 1, Δ represents the difference between the glossy and image-capturing pigment inks only and the recorded material in each example, and a negative value when the evaluation value is inferior to that of the pigment ink alone. Is displayed.

Example 1
After image recording of pigment ink, in the first application step, after applying with clear ink A with 8 passes and 100% duty, the recording medium is discharged once, fed back to the printer, and a different nozzle row is set. The clear ink B was applied in one pass. At that time, ink was ejected from all 512 nozzles in the nozzle row, and the sub-scanning was controlled to a width corresponding to 508 nozzles so that the inks applied in one scan were overlapped.

  The glossiness and image clarity of only the pigment ink are greatly improved by applying the clear ink, and the clear ink application in the second application process is good without any joint streaks even though it is performed in one pass. Recorded material was output.

(Example 2)
After the image recording of the pigment ink, the clear ink application in the second application process was performed in the same manner as in Example 1 except that the clear ink application in the first application process was changed to 6-pass 100% duty. The glossiness and image clarity of only the pigment ink were greatly improved by applying the clear ink, and a good recorded product could be output without generating a connecting stripe.

(Example 3)
After the image recording of the pigment ink, the clear ink application in the second application process was performed in the same manner as in Example 1 except that the clear ink application in the first application process was changed to 4 pass 100% duty. The glossiness and image clarity of only the pigment ink were greatly improved by applying the clear ink, and a good recorded product could be output without generating a connecting stripe.

Example 4
After the image recording of the pigment ink, the clear ink application in the second application process was performed in the same manner as in Example 1 except that the clear ink application in the first application process was changed to 2-pass 100% duty. The glossiness and image clarity of the pigment ink alone were greatly improved by applying clear ink. Although the connecting stripe was visually recognized with some colors, it was possible to output a recorded matter having no practical problem.

As described above, as shown in the embodiment, the clear ink application in the first application process performs the multi-pass recording, and the second application process performs the 1-pass recording. The original glossiness can be improved.

  A comparative example is shown below. Table 1 shows the results of glossiness and image clarity, which are indicators of glossiness in the recorded matter recorded only with the pigment ink, and the comparative examples, and the visual evaluation results of the connecting stripes. In Table 1, Δ represents the difference between the glossy and image-capable pigment inks only and the recorded material in each comparative example, and a negative value when the evaluation value is inferior to that of the pigment ink alone. Is displayed.

(Comparative Example 1)
After recording an image of the pigment ink, the clear ink B was applied with an 8-pass 100% duty. The connection streaks were good without any occurrence, but depending on the pigment ink color, the glossiness and image clarity may be deteriorated. End up.

(Comparative Example 2)
After image recording of pigment ink, clear ink B was applied in one pass. At that time, ink was ejected from all 512 nozzles in the nozzle row, and the sub-scanning was controlled to a width corresponding to 508 nozzles so that the inks applied in one scan were overlapped. The glossiness and image clarity of the pigment ink alone are improved by applying the clear ink, but the connecting stripe is visually recognized, and the image quality is remarkably deteriorated and cannot be put to practical use.

(Comparative Example 3)
After the clear ink A was applied on the pigment ink image in one pass by the same method as in Comparative Example 2, the clear ink B was further applied in one pass by the same method. The glossiness and image clarity of the pigment ink alone are improved by applying the clear ink, but the connecting stripe is visually recognized, and the image quality is remarkably deteriorated and cannot be put to practical use.

(Comparative Example 4)
After the clear ink A was applied on the pigment ink image in one pass by the same method as in Comparative Example 2, the clear ink B was further applied in 8 passes 100. The glossiness and image clarity of the pigment ink alone are improved by applying the clear ink, but the connecting stripe is visually recognized, and the image quality is remarkably deteriorated and cannot be put to practical use.

  In the comparative example described above, sufficient glossiness cannot be obtained by applying clear ink in one pass with clear ink application, and glossiness is improved to some extent in one-pass printing. Is visually recognized and the image quality is deteriorated. In addition, even when the clear ink is applied in two steps, when the single clear printing is performed in the first clear ink application step, the connecting streak between scans in the clear ink layer in the first step is performed. Will occur. As a result, even if the second clear ink is applied thereafter, the above-mentioned connecting stripe is visually recognized, and the image quality is deteriorated.

DESCRIPTION OF SYMBOLS 101 Recording medium 102 Pigment ink 103 Clear ink provided by the 1st process 104 Clear ink provided by the 2nd process 501 Nozzle 502 Nozzle row | line | column for discharging pigment ink 503 Nozzle for discharging 1st clear ink Row 504 Nozzle row for discharging the second clear ink 43 CPU
45 RAM
46 Image data processor

Claims (4)

A main scan that scans the recording medium and a sub-scan that conveys the recording medium are performed using a recording head that discharges ink and clear ink for increasing the glossiness of the recorded matter. The recording is performed during the main scanning. An inkjet recording apparatus that performs recording by discharging ink or clear ink from a head,
A recording step of recording an image by ejecting ink from the recording head and applying ink to the recording medium, and performing a plurality of main scans using the recording head on an area including the area where the image is recorded on the recording medium. A first application step of discharging clear ink from the recording head in the plurality of main scans to apply the clear ink to the recording medium, and applying the clear ink at least in the first application step after the first application step. A second application step is performed in which the main scanning is performed once on the area using the recording head, the clear ink is ejected from the recording head and the clear ink is applied to the recording medium in the one main scanning. Recording control means,
An ink jet recording apparatus comprising:   In the second application step of applying the clear ink, the amount of the sub-scan is made smaller than the width of the nozzle row in the recording head, thereby clearing the entire width over the width of the sub-scan in the one main scan. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus covers an ink.   3. The clear ink is applied in the second application step of applying the clear ink, by using a plurality of nozzle rows so as to cover the entire area of the width more than the amount of the sub-scan in one scan. 2. An ink jet recording apparatus according to 1. A main scan that scans the recording medium and a sub-scan that conveys the recording medium are performed using a recording head that discharges ink and clear ink for increasing the glossiness of the recorded matter. The recording is performed during the main scanning. An inkjet recording method for recording by discharging ink or clear ink from a head,
A recording step of recording an image by discharging ink from a recording head and applying ink to a recording medium;
A plurality of main scans using a recording head are performed on an area including the area where the image is recorded on the recording medium, and clear ink is applied to the recording medium by discharging clear ink from the recording head in the plurality of main scanning. A first applying step,
After the first application step, at least one main scan using the recording head is performed on the region to which the clear ink has been applied in the first application step, and the clear ink is discharged from the print head in the one main scan. A second applying step of discharging the ink and applying a clear ink to the recording medium;
An ink jet recording method comprising:

Images