JP2017105194A - Liquid discharge unit, liquid discharge device and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge unit, a liquid discharge device and a printing method which can deal with various printing modes and perform printing at the high speed in the respective printing modes.SOLUTION: A liquid discharging unit includes: a first nozzle group 20a that includes nozzle arrays each in which nozzle holes for discharging liquids of process colors for image formation are arranged in a sub scanning direction perpendicular to a main scanning direction; a second nozzle group 20c and a third nozzle group 20c that are provided on upstream side and downstream side in the sub scanning direction with respect to the first nozzle group 20a, arranged so as to be shifted in the main scanning direction with respect to the first nozzle group 20a and include nozzle arrays each in which nozzle holes for discharging liquids in the different color from the process colors are arranged in the sub scanning direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liquid discharge unit, a liquid discharge apparatus, and a printing method.

  Conventionally, in the sign graphics field such as an advertisement displayed indoors and outdoors, black (K), yellow (Y), magenta (M), cyan (C) process color image forming ink, white ink, 2. Description of the Related Art An ink jet type liquid ejecting apparatus equipped with auxiliary ink having a color different from a process color such as metallic ink is used. Such a liquid discharge device, for example, first prints (applies) auxiliary ink (background ink or background ink) such as white ink on the entire surface of a transparent medium that is a printing object, and then forms an image with image forming ink on the auxiliary ink. Print.

  Here, as in either of the case where the auxiliary ink (for example, white ink) is applied to the entire surface of the printing material and the case where the auxiliary ink is applied only to a place where the image of the printing material is formed, A state in which auxiliary ink is applied to a place that overlaps with a place where an image is formed is referred to as “form a base”. In addition, a state in which auxiliary ink is applied to a place that does not overlap with a place where an image is formed is referred to as “form a background”. Therefore, “form the background and the background” represents an aspect in which auxiliary ink is applied to the entire surface of the printing material. In addition, “form a background or background” is an aspect in which the place where an image is formed on the substrate and the place where the auxiliary ink is applied do not completely match, for example, the auxiliary ink layer on a part of the portion overlapping the image In other words, the auxiliary ink layer is present in a part of the place where the image is not formed, not on the entire surface of the substrate.

  In addition to the KCMY, the liquid ejection device can add special color inks such as light cyan, light magenta, and gray to the image forming ink in order to improve the granularity. The printer apparatus can also add special color inks such as orange, green, and red to the image forming ink in order to improve color reproducibility.

  Patent Document 1 discloses a technique that includes a head that discharges a recording liquid (ink) having a special color different from KCMY (process color), and reduces the difference between the reciprocal colors using the special color recording liquid.

  However, according to the technique disclosed in Patent Document 1, there is a problem that it is not possible to cope with various print modes by using spot color ink more effectively.

  The present invention has been made in view of the above, and provides a liquid discharge unit, a liquid discharge apparatus, and a printing method that can cope with various print modes and can perform high-speed printing in each print mode. Objective.

  In order to solve the above-described problems and achieve the object, the present invention provides a first nozzle array in which a plurality of nozzle holes for ejecting a process color liquid for image formation are arranged in the sub-scanning direction orthogonal to the main scanning direction. One nozzle group is provided on the upstream side and the downstream side in the sub-scanning direction with respect to the first nozzle group, and the first nozzle group is disposed so as to be shifted from each other in the main scanning direction. A second nozzle group and a third nozzle group having a nozzle row in which a plurality of nozzle holes for discharging liquids of different colors are arranged in the sub-scanning direction are provided.

  According to the present invention, it is possible to cope with various print modes, and it is possible to perform printing at high speed in each print mode.

FIG. 1 is a schematic diagram illustrating the configuration of the ink jet recording apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a control configuration of the ink jet recording apparatus. FIG. 3 is a plan view showing the nozzle configuration of the recording head. FIG. 4 is an explanatory diagram showing an example of the printing operation of the recording head. FIG. 5 is an explanatory diagram showing an example of the printing operation of the recording head. FIG. 6 is an explanatory diagram showing an example of the printing operation of the recording head. FIG. 7 is an explanatory diagram showing an example of the printing operation of the recording head. FIG. 8 is an explanatory diagram showing an example of the printing operation of the recording head. FIG. 9 is an explanatory diagram showing an example of the printing operation of the recording head. FIG. 10 is a diagram illustrating an example of a print result. FIG. 11 is a diagram illustrating an example of a print result in which image blurring occurs. FIG. 12 is an explanatory diagram illustrating an example of the printing operation of the recording head according to the second embodiment. FIG. 13 shows a drying apparatus according to the third embodiment, wherein (a) is a plan view and (b) is a front view.

  Hereinafter, embodiments of a liquid discharge unit, a liquid discharge apparatus, and a printing method will be described in detail with reference to the accompanying drawings. In the present embodiment, an example in which a recording head is applied as a liquid discharge unit and an ink jet recording apparatus is applied as a liquid discharge device will be described.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a configuration of an inkjet recording apparatus 1 according to the first embodiment. The ink jet recording apparatus 1 which is a liquid ejection apparatus is a serial type ink jet recording apparatus. As shown in FIG. 1, the inkjet recording apparatus 1 includes an image forming unit 2 that prints a required image, a drying device 3, a roll media storage unit 4, and a transport mechanism 5. The roll medium storage unit 4 stores a roll medium (recording medium) 40 that is a printed material. Note that the roll media storage unit 4 can store recording media 40 having different sizes in the width direction. The recording medium 40 is a transparent non-penetrable medium such as a PET (polyethylene terephthalate) film.

  The transport mechanism 5 constitutes a roll-to-roll transport means. The transport mechanism 5 includes a pair of nip rollers 51, a pair of driven rollers 52, and a take-up roller 53 on the transport path 54 of the recording medium 40. The nip roller 51 is provided on the front side (upstream side in the transport direction A) of the image forming unit 2. The nip roller 51 rotates with the driving of the motor M (see FIG. 2) and conveys the recording medium 40 sandwiched therebetween toward the image forming unit 2. Further, the take-up roller 53 takes up the recording medium 40 after printing by rotating as the motor M is driven. The driven roller 52 rotates following the conveyance of the recording medium 40.

  The transport mechanism 5 includes a wheel encoder 55 (see FIG. 2) for detecting the transport speed. The transport mechanism 5 is controlled in the transport speed by the control of the motor M based on the target value and the speed detection value obtained by sampling the detection pulse from the wheel encoder 55.

  That is, the recording medium 40 stored in the roll medium storage unit 4 is conveyed to the image forming unit 2 by the rotation of the nip roller 51 via the driven roller 52. The recording medium 40 that has reached the image forming unit 2 is printed with a required image by the image forming unit 2. Then, the recording medium 40 after printing is wound up by the rotation of the winding roller 53.

  The image forming unit 2 includes a carriage 21. The carriage 21 is slidably held by a guide rod (guide rail) 22. As the motor M is driven, the carriage 21 moves on the guide rod (guide rail) 22 in a direction (main scanning direction) orthogonal to the conveyance direction A of the recording medium 40. More specifically, the carriage 21 is in a recording area that can be printed by the image forming unit 2 on the recording medium 40 conveyed by the conveyance mechanism 5 in the main scanning area that is movable in the main scanning direction. Move back and forth.

  The carriage 21 carries a recording head 20 in which a plurality of nozzle holes, which are ejection openings for ejecting droplets, are arranged. The recording head 20 is integrally provided with a tank that supplies ink to the recording head 20. However, the recording head 20 is not limited to the one having the tank integrally, and may be one having the tank separately. The recording head 20 functions as a liquid discharge unit, and discharges ink droplets of black (K), yellow (Y), magenta (M), and cyan (C), which are process color recording liquids. . Black (K), yellow (Y), magenta (M), and cyan (C) are inks for image formation. In addition, the recording head 20 ejects white (W) ink droplets, which are auxiliary inks (background ink and background ink). Further, the recording head 20 ejects ink of each color of orange (O) and green (G), which are recording liquids of special colors having a hue different from those of the process color recording liquids used for improving color reproducibility. .

  Here, in the case where auxiliary ink (for example, white ink (white ink)) is applied to the entire surface of the recording medium 40 which is a printing object, and the auxiliary ink is applied only to the place where the image of the recording medium 40 is formed. The state in which the auxiliary ink is applied to a place that overlaps with the place where the image is formed as in the case where the application is performed is referred to as “form the base”. In addition, a state in which auxiliary ink is applied to a place that does not overlap with a place where an image is formed is referred to as “form a background”. Therefore, “form a background and a background” represents an aspect in which auxiliary ink is applied to the entire surface of the recording medium 40. “Forming a background or background” is an aspect in which the place where the image is formed on the recording medium 40 and the place where the auxiliary ink is applied do not completely match, for example, a part of the portion overlapping the image is supported. This represents an aspect in which there is an ink layer, and there is an auxiliary ink layer in a part of the recording medium 40 where an image is not formed, rather than the entire surface.

  The image forming unit 2 includes a platen 23 that supports the recording medium 40 below the recording head 20 during printing by the recording head 20.

  Further, the image forming unit 2 includes an encoder sheet for detecting the main scanning position of the carriage 21 along the main scanning direction of the carriage 21. The carriage 21 includes an encoder 26 (see FIG. 2). The image forming unit 2 detects the main scanning position of the carriage 21 by reading the encoder sheet with the encoder 26 of the carriage 21.

  The carriage 21 includes a sensor 24 that optically detects the end of the recording medium 40 as the carriage 21 moves. The detection signal from the sensor 24 is used to calculate the position of the end of the recording medium 40 in the main scanning direction and the width of the recording medium 40.

  The drying device 3 includes a preheater 30, a platen heater 31, a drying heater 32, and a hot air fan 33. The preheater 30, the platen heater 31, and the drying heater 32 are electric heaters using, for example, ceramic or nichrome wire.

  The preheater 30 is provided upstream of the image forming unit 2 in the conveyance direction A of the recording medium 40. The preheater 30 preliminarily heats the recording medium 40 transported by the transport mechanism 5.

  The platen heater 31 is disposed on the platen 23. The platen heater 31 heats the recording medium 40 for landing the ink droplets ejected from the nozzle holes of the recording head 20.

  The drying heater 32 is provided downstream in the transport direction A of the recording medium 40 with respect to the image forming unit 2. The drying heater 32 continues to heat the recording medium 40 printed by the image forming unit 2 and promotes drying of the landed ink droplets.

  The hot air fan 33 is provided downstream in the transport direction A of the recording medium 40 with respect to the drying heater 32 (image forming unit 2). The hot air fan 33 blows hot air against the recording surface of the recording medium 40 landed with ink. The hot air fan 33 applies hot air directly to the ink on the recording surface of the recording medium 40 to reduce the humidity of the atmosphere around the recording surface of the recording medium 40 and completely dry it.

  By mounting such a drying device 3, the ink jet recording apparatus 1 can employ a non-penetrable medium in which ink such as vinyl chloride, PET, and acrylic does not permeate as the recording medium 40. When the non-penetrable medium is employed, the ink jet recording apparatus 1 may employ a solvent-based ink that is well fixed to the non-penetrable medium or an aqueous resin ink with a large amount of resin components as the ink used for the image forming unit 2. it can.

  In the ink jet recording apparatus 1 that forms an image by ejecting ink from the recording head 20 while the carriage 21 reciprocates in the width of the recording medium 40, the ink is ejected only when the carriage operation is in the forward path. There are unidirectional printing to be formed and bidirectional printing to form an image by ejecting ink in both the forward and backward carriage operations. In the ink jet recording apparatus 1, bidirectional printing which is advantageous in terms of printing speed is mainly used. Here, the operation of ejecting ink from the recording head 20 while the carriage 21 moves in the main scanning direction is one scan.

  Next, the control configuration of the inkjet recording apparatus 1 will be described. Here, FIG. 2 is a block diagram showing a control configuration of the inkjet recording apparatus 1.

  As shown in FIG. 2, the ink jet recording apparatus 1 includes a control unit 10 that controls the entire apparatus. The control unit 10 includes a central processing unit (CPU) 11, a read only memory (ROM) 12, a random access memory (RAM) 13, a memory 14, and an application specific integrated circuit (ASIC) 15. I have. The ROM 12 stores computer programs executed by the CPU 11 and other fixed data. The RAM 13 temporarily stores image data and the like. The memory 14 is a rewritable nonvolatile memory that retains data even when the power of the inkjet recording apparatus 1 is shut off. The ASIC 15 executes image processing for performing various signal processing and rearrangement on the image data, and other input / output signal processing for controlling the entire apparatus.

  As shown in FIG. 2, the control unit 10 includes a host interface (I / F) 16, a head drive control unit 17, a motor control unit 18, and an I / O 19.

  The host I / F 16 transmits and receives image data (print data) and control signals to and from the host side via a cable or a network. Examples of the host connected to the inkjet recording apparatus 1 include an information processing apparatus such as a personal computer, an image reading apparatus such as an image scanner, and an imaging apparatus such as a digital camera.

  The I / O 19 receives detection pulses from the encoder 26 and the wheel encoder 55. In addition, the I / O 19 connects various sensors 25 such as a humidity sensor, a temperature sensor, and other sensors in addition to the sensor 24. The I / O 19 inputs detection signals from the sensor 24 and various sensors 25.

  The head drive control unit 17 controls the drive of the recording head 20 and includes a data transfer unit. More specifically, the head drive control unit 17 transfers the image data as serial data. The head drive control unit 17 generates a transfer clock and a latch signal necessary for transferring image data and confirming the transfer, and a drive waveform used when ejecting droplets from the recording head 20. Then, the head drive control unit 17 inputs the generated drive waveform or the like to a drive circuit inside the recording head 20.

  The motor control unit 18 drives the motor M. More specifically, the motor control unit 18 calculates a control value based on a target value given from the CPU 11 side and a speed detection value obtained by sampling a detection pulse from the wheel encoder 55. And the motor control part 18 drives the motor M based on the calculated control value via an internal motor drive circuit.

  The control unit 10 includes a heater control unit 8 and a hot air fan control unit 9.

  The heater control unit 8 controls the output of the preheater 30, the platen heater 31, and the drying heater 32 so that the temperature of each of the heaters 30, 31, and 32 becomes a set temperature. More specifically, when controlling the heaters 30, 31, and 32, the heater control unit 8 acquires temperature information using temperature sensors provided in the heaters 30, 31, and 32. And the heater control part 8 is controlled so that the temperature of each heater 30,31,32 may become set temperature, monitoring the temperature of each heater 30,31,32. In the case where a heater is provided on the tank or ink path of the recording head 20, the heater control unit 8 controls this heater in the same manner.

  The warm air fan control unit 9 controls the output of the warm air fan 33 so that the air is blown at a predetermined temperature and air volume.

  In addition, the control unit 10 connects an operation panel 60 for inputting and displaying information necessary for the inkjet recording apparatus 1.

  The control unit 10 centrally controls each unit by loading the computer program read from the ROM 12 (or the memory 14) by the CPU 11 into the RAM 13 and executing it. More specifically, based on the print mode set from the operation panel 60, the CPU 11 reads the control content set for each print mode from the ROM 12 (or the memory 14). And CPU11 performs control mentioned later by controlling each part based on the contents of control read from ROM12 (or memory 14).

  The computer program executed by the inkjet recording apparatus 1 according to the present embodiment is a file in an installable format or an executable format, and is a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk). Or the like recorded on a computer-readable recording medium.

  Further, the computer program executed in the inkjet recording apparatus 1 of the present embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the computer program executed by the inkjet recording apparatus 1 of the present embodiment may be provided or distributed via a network such as the Internet.

  Further, the computer program executed by the ink jet recording apparatus 1 of the present embodiment may be configured to be provided by being incorporated in advance in a ROM or the like.

  Next, the image data transfer printing process executed by the control unit 10 of the inkjet recording apparatus 1 will be briefly described. The CPU 11 of the control unit 10 reads and analyzes image data (print data) in the reception buffer included in the host I / F 16 and performs necessary image processing, data rearrangement processing, and the like in the ASIC 15. Next, the CPU 11 of the control unit 10 transfers the image data (print data) processed by the ASIC 15 from the head drive control unit 17 to the recording head 20.

  The dot pattern data for image output may be generated, for example, by storing font data in the ROM 12, or the image data is developed into bitmap data by the host-side printer driver and is stored in the inkjet recording apparatus 1. You may make it forward.

  Next, characteristic functions of the inkjet recording apparatus 1 of the present embodiment will be described. The ink jet recording apparatus 1 according to the present embodiment can cope with various print modes when ink jet printing is performed on the recording medium 40 which is a transparent non-penetrable medium, can print at high speed in each print mode, and is insufficiently dried. This makes it possible to reduce the bleeding of the image.

  Here, FIG. 3 is a plan view showing the nozzle configuration of the recording head 20. FIG. 3 shows the nozzle row of the recording head 20 transparently from the upper surface. As shown in FIG. 3, the recording head 20 includes a first nozzle group 20a, a second nozzle group 20b, and a third nozzle group 20c.

  As shown in FIG. 3, the first nozzle group 20a, the at least one second nozzle group 20b, and the third nozzle group 20c are arranged with their positions shifted in the main scanning direction. In particular, in FIG. 3, the nozzle groups 20a, 20b, and 20c are arranged in two rows in the main scanning direction and alternately in a staggered manner in the sub-scanning direction. That is, each nozzle group 20a, 20b, 20c has the second nozzle group 20b, the first nozzle group 20a, the first nozzle group so that the nozzle rows do not overlap from the upstream side to the downstream side in the transport direction A of the recording medium 40. The three nozzle groups 20c are arranged in this order. Further, as shown in FIG. 3, the first nozzle group 20a is disposed with a position shifted in the main scanning direction from the second nozzle group 20b and the third nozzle group 20c.

  The first nozzle group 20a includes four nozzle rows that discharge KCMY (process color) ink droplets for image formation. Each nozzle row has a nozzle number no. No. 1 nozzle no. There are 192 nozzle holes of 192 nozzle holes. In the example shown in FIG. 3, each nozzle hole has a nozzle number No. 1 from the downstream nozzle hole in the conveyance direction A of the recording medium 40 toward the upstream nozzle hole. No. 1 to No. No. 192. The pitch P between these nozzle holes is 150 dpi (dots per inch).

  The first nozzle group 20a discharges yellow (Y) ink droplets, a yellow ink nozzle row NY, magenta (M) ink droplets, a magenta ink nozzle row NM, and cyan (C) ink droplets. A cyan ink nozzle row NC and a black ink nozzle row NK that discharges black (K) ink droplets.

  Similarly to the first nozzle group 20a, each row of the second nozzle group 20b and the third nozzle group 20c has a nozzle number No. No. 1 to No. No. It has four nozzle rows having 192 nozzle holes of 192. Similarly to the first nozzle group 20a, the pitch P between the nozzle holes of the second nozzle group 20b and the third nozzle group 20c is 150 dpi.

  The second nozzle group 20b and the third nozzle group 20c are provided with auxiliary recording nozzle rows. Specifically, the second nozzle group 20b and the third nozzle group 20c discharge two rows of nozzles that eject ink droplets of the background and / or background forming colors and ink droplets of the special colors for image formation. And two nozzle rows.

  The second nozzle group 20b and the third nozzle group 20c have two nozzle rows NW that eject white (W) ink droplets as an example of background and / or background forming ink. Further, the second nozzle group 20b and the third nozzle group 20c discharge nozzles NO that discharge orange (O) ink droplets and green (G) ink droplets as an example of special color ink for image formation. It has a nozzle row NG.

  As described above, since each nozzle group 20a, 20b, 20c has the same number of nozzle rows and the same number of nozzles, each nozzle group 20a, 20b, 20c can be composed of the same parts, so that Therefore, the cost of the apparatus can be reduced.

  Here, the printing operation by the nozzle groups 20a, 20b, and 20c of the recording head 20 will be described. Here, a case where printing is performed with 16 scans of 4 passes and 1/4 interlace is taken as an example. Since the pitch P between the nozzle holes of each nozzle row is 150 dpi, an image of 600 dpi in the sub-scanning direction is formed when printing with 1/4 interlace.

[White background → Color image (4 colors)]
FIG. 4 is an explanatory diagram showing an example of the printing operation of the recording head 20. The example shown in FIG. 4 is a mode in which a color image (four colors) is formed after a white background is formed as a background and a background. In the example shown in FIG. 4, nozzle rows NW, NW, NY, NC, NM, and NK surrounded by broken lines are used.

  First, the control unit 10 of the inkjet recording apparatus 1 forms a white background and background solid using the two nozzle rows NW of the second nozzle group 20b. The two nozzle rows NW for forming the background and the background are arranged at 300 dpi (150 dpi × 2). Normally, a sub-scanning 600 dpi image can be ½ interlaced with a 300 dpi nozzle array. However, since the quarter interlace is used here, the base and the white solid for the background are doubled, and the ink layer is formed thick. Therefore, the recording medium 40 can obtain a sufficient light shielding property when a ground or background is formed with white solid.

  Next, after the white solid is completed, the control unit 10 of the inkjet recording apparatus 1 uses the nozzle rows NY, NC, NM, and NK of the first nozzle group 20a to form an image by KCMY (process color) for image formation. Is formed on a white solid. In this case, an image using KCMY four-color ink is a sub-scanning 600 dpi image by four passes and 1/4 interlaced 16 scans.

[White background → Color image (6 colors)]
FIG. 5 is an explanatory diagram showing an example of the printing operation of the recording head 20. The example shown in FIG. 5 is a mode in which a color image (six colors) is formed after forming a background or background with solid white. In the example shown in FIG. 5, nozzle rows NW, NW, NY, NC, NM, NK, NO, NG surrounded by broken lines are used.

  First, as in the example of FIG. 4, the control unit 10 of the inkjet recording apparatus 1 forms a white background and background solid using the two nozzle rows NW of the second nozzle group 20 b. Thereafter, as in the example of FIG. 4, the control unit 10 of the inkjet recording apparatus 1 uses the nozzle rows NY, NC, NM, and NK of the first nozzle group 20 a to form an image by KCMY (process color) for image formation. Is formed on a white solid.

  Next, the control unit 10 of the inkjet recording apparatus 1 adds an image with orange and green special colors using the nozzle rows NO and NG of the third nozzle group 20c. In the example shown in FIG. 5, an image with a wider color gamut can be formed by adding such a special color.

  When the special color dots are printed so as to be positioned closer to the observation surface than the process color dots, the effect of the special color can be more efficiently extracted, and it is effective for increasing the color gamut. In this embodiment, since the process colors yellow, cyan, magenta, and black are formed and the special colors orange and green are printed, the special color dots are printed above the process color and the color gamut is increased. It is effective to enlarge.

[Color image (6 colors) → White top coat]
FIG. 6 is an explanatory diagram showing an example of the printing operation of the recording head 20. The example shown in FIG. 6 is a reverse printing mode in which printing is performed on a transparent recording medium 40 and observed from the surface opposite to the printed surface. The example shown in FIG. 6 is an example in which after forming a color image (six colors), white is overcoated to provide a white ink layer, and a base and a background are formed when viewed from the observation surface. In the example shown in FIG. 6, nozzle rows NO, NG, NY, NC, NM, NK, NW, and NW surrounded by broken lines are used.

  First, the control unit 10 of the inkjet recording apparatus 1 forms an image with orange and green special colors using the nozzle rows NO and NG of the third nozzle group 20c. After the orange and green image formation is completed, the control unit 10 of the inkjet recording apparatus 1 uses the nozzle rows NY, NC, NM, and NK of the first nozzle group 20a to perform KCMY (process color) for image formation. Form an image.

  After the image is completed, the control unit 10 of the inkjet recording apparatus 1 forms a white solid using the two nozzle rows NW of the second nozzle group 20b, and displays the background and background when viewed from the observation surface. It is an example of forming.

  In the example shown in FIG. 6, by observing the completed printed matter from the back side, an image in which a color image is formed using a white solid as a base and a background. Here, when printing, the special colors orange and green are printed earlier than the process colors yellow, cyan, magenta and black, so the orange and green dots are on the top when viewed from the observation surface side. To position. In the present embodiment, the spot color dots are positioned closer to the observation surface than the process color dots, so that the effect of the spot colors can be extracted more efficiently and the color gamut can be increased.

[Color images (6 colors)]
FIG. 7 is an explanatory diagram showing an example of the printing operation of the recording head 20. The example shown in FIG. 7 is a mode in which a color image with a special color is printed when a recording medium such as white is used instead of the transparent recording medium 40. In the example shown in FIG. 7, nozzle rows NY, NC, NM, NK, NO, NG surrounded by broken lines are used.

  First, the control unit 10 of the inkjet recording apparatus 1 forms an image by KCMY (process color) for image formation using the nozzle rows NY, NC, NM, and NK of the first nozzle group 20a.

  Next, the control unit 10 of the inkjet recording apparatus 1 adds an image with orange and green special colors using the nozzle rows NO and NG of the third nozzle group 20c. In the example shown in FIG. 7, an image with a wider color gamut can be formed by adding such a special color.

  When the special color dots are printed so as to be positioned closer to the observation surface than the process color dots, the effect of the special color can be more efficiently extracted, and it is effective for increasing the color gamut. In this embodiment, since the process colors yellow, cyan, magenta, and black are formed and the special colors orange and green are printed, the special color dots are printed above the process color and the color gamut is increased. It is effective to enlarge.

[Color image (4 colors)]
FIG. 8 is an explanatory diagram showing an example of the printing operation of the recording head 20. The example shown in FIG. 8 is a mode for forming a color image (four colors) when a recording medium such as white is used instead of the transparent recording medium 40. In the example shown in FIG. 8, nozzle rows NY, NC, NM, NK surrounded by broken lines are used.

  The control unit 10 of the inkjet recording apparatus 1 forms an image by KCMY (process color) for image formation using the nozzle rows NY, NC, NM, NK of the first nozzle group 20a.

  In this embodiment, printing can be performed only with the first nozzle group 20a. Therefore, since the print width in the sub-scanning direction is the nozzle row length of the first nozzle group 20a, the number of scans at the start and end of image writing is smaller than when printing using two heads. As a result, the printing speed is increased.

[White background → color image (4 colors) modification]
FIG. 9 is an explanatory diagram showing an example of the printing operation of the recording head 20. The example shown in FIG. 9 is a mode for forming a color image (four colors) after forming white as a base and a background. In the example shown in FIG. 9, nozzle rows NW, NW, NY, NC, NM, and NK surrounded by broken lines are used.

  The difference from the example shown in FIG. 4 is that, as shown in FIG. 9, only one half of the portion away from the first nozzle group 20a is used for the two nozzle rows NW of the second nozzle group 20b. is there. By doing this, the time from the completion of the white solid as the background and the background to the start of image formation using the nozzle rows NY, NC, NM, NK of the first nozzle group 20a on the white solid is increased. Can be long.

  When forming a color image on a white solid, depending on the ink characteristics, printing speed, and media heating time, the white solid may not be sufficiently dried and the color ink struck on it may sink or sink into the white ink layer. There are things to do. According to the present embodiment, the drying time of the white solid ink until the color image is formed on the white solid becomes longer, and image defects can be reduced.

  Further, since the number of nozzles to be driven is reduced for the two nozzle rows NW of the second nozzle group 20b, the ink droplet ejection frequency may be doubled. Thereby, even if there are few nozzles, it can print at the same speed as image printing.

  For example, in the example shown in FIG. 4, when the image formed by the two nozzle rows NW of the second nozzle group 20b is printed by four passes and 1/4 interlaced 16 scans, the second nozzle group of the present embodiment. The base and background formed by the two nozzle rows NW of 20b are formed by 8 passes of 2 passes and 1/4 interlace.

  The background and background printing need only be solid images, and halftone and high-definition printing is not necessary. Therefore, multi-value dots are not necessary and binary dots are sufficient, and the drive waveform can be a simple shape, so that the ejection frequency can be increased. In addition, the background and background are printed with a smaller number of scans than the image formation, but only a solid image with only the background and background colors is printed, and there is no color boundary. unnecessary. For this reason, even if the number of scans is reduced, image defects do not occur.

  As described above, according to the present embodiment, it is possible to cope with various print modes, and it is possible to print at high speed in each mode.

  In addition, according to the present embodiment, image bleeding due to insufficient drying can be reduced.

  In this embodiment, orange and green are applied as the special colors. However, the present invention is not limited to this, and special colors such as red and blue, or light inks such as light cyan, light magenta, and gray may be used as the special colors.

  In this embodiment, the white ink is applied as the auxiliary ink. However, the present invention is not limited to this. The ink jet recording apparatus 1 can apply silver ink, gold ink, transparent ink, a primer, a surface protecting agent, and the like as auxiliary ink. Such auxiliary ink is basically an image layer formed with image forming ink, and an auxiliary layer is formed on the front or back of the image layer to improve image quality or add texture. Used to do.

  The auxiliary ink may be applied to the entire surface of the recording medium 40, which is a substrate to be printed (for background and background), or may be applied to a part of the recording medium 40 (for background). Moreover, when apply | coating to some recording media 40, you may apply | coat to the location same as the location which records, for example, or may apply to the location which is partially common with the location which records. .

  Further, in this embodiment, the process color for image formation includes black ink, but the process color for image formation may be configured not to include black ink.

  The printing using the inkjet recording apparatus 1 of the present embodiment can obtain a good result without bleeding as shown in FIG.

  On the other hand, printing using a conventional recording head causes image quality defects such as bleeding as shown in FIG.

(Second Embodiment)
Next, a second embodiment will be described. In addition, the same part as 1st Embodiment mentioned above is shown with the same code | symbol, and description is also abbreviate | omitted.

  FIG. 12 is an explanatory diagram illustrating an example of a printing operation of the recording head 20 according to the second embodiment. As shown in FIG. 12, the recording head 20 of this embodiment has a configuration in which the distance in the transport direction A of the recording medium 40 between the first nozzle group 20a, the second nozzle group 20b, and the third nozzle group 20c is increased. It is said. By doing so, the drying time of the white solid ink until the color image is formed on the white solid can be lengthened.

  The recording head 20 of the present embodiment shown in FIG. 12 can obtain the drying time even when the base of the second nozzle group 20b and the background forming nozzle row NW are used in all channels.

  Further, the third nozzle group 20c is formed on the color image formed by the first nozzle group 20a by widening the distance in the transport direction A of the recording medium 40 between the first nozzle group 20a and the third nozzle group 20c. In the case of forming a white solid (back printing), it is possible to reduce the bleeding that occurs between the color image and the white solid thereon.

(Third embodiment)
Next, a third embodiment will be described. In addition, the same part as 1st Embodiment mentioned above is shown with the same code | symbol, and description is also abbreviate | omitted.

  In the first embodiment, an example is described in which the ink is cured by heating the heater using the drying device 3 and the image is fixed on the recording medium 40. In the present embodiment, when an ink that is cured by energy of radiation such as UV light (ultraviolet light) is used, the ink is cured by a method different from that of the first embodiment.

  FIG. 13 shows a curing device 80 according to the third embodiment, wherein (a) is a plan view and (b) is a front view. As shown in FIG. 13, in the inkjet recording apparatus 1, a carriage 21 is supported on a guide rod 22. The carriage 21 reciprocates in the main scanning direction according to the guide rod 22.

  The ink jet recording apparatus 1 has a recording head 20 mounted on a carriage 21. On both sides of the recording head 20, an ultraviolet irradiation device is provided as a curing device 80 that irradiates the ink discharged to the recording medium 40 with ultraviolet rays.

  With such a configuration, the ink jet recording apparatus 1 sequentially irradiates the ink ejected from the recording head 20 by the curing device 80 and landed on the recording medium 40 with ultraviolet rays from the ultraviolet irradiation device as the curing device 80. Thereby, the ink jet recording apparatus 1 can cure and fix the ink that is cured by the UV light (ultraviolet light) on the recording medium 40.

  The ink used in the ink jet recording apparatus 1 according to the first embodiment to the third embodiment is not particularly limited. In particular, in the ink jet recording apparatus 1, when an ink containing water, an organic solvent, a color material, resin particles, and a siloxane compound is used, the drying property can be improved and bleeding can be suitably suppressed.

<Siloxane compound>
Of the components contained in the ink used in the inkjet recording apparatus 1, the siloxane compound affects the ink fixing property to the non-penetrable medium (recording medium 40) to be recorded. Therefore, the role played by the siloxane compound is very large. The present inventors have found that adding a siloxane compound to the ink significantly improves the drying properties of the ink. More specifically, by adding a siloxane compound to the ink, the affinity with various non-penetrable media (recording medium 40) is improved, and the ink spreads immediately after adhering to the non-penetrable medium (recording medium 40). This is presumably because the surface area is enlarged and the drying efficiency is increased. By improving the drying property of the ink to the non-penetrable medium (recording medium 40), the white color is printed with the process color ink after forming the background and / or the background with the white ink, and the image with the process color ink. Even when white post-printing or the like in which an ink layer is formed with white ink after formation is performed, the occurrence of blurring at the color boundary can be suppressed, and a high-quality image can be obtained.

As the siloxane compound, for example, a compound having a polysiloxane moiety such as polydimethylsiloxane (silicone compound) and / or a compound having a hydrophilic group or a hydrophilic polymer chain at the terminal is common. Examples of hydrophilic groups and hydrophilic polymer chains include polyether bonds (polyethylene oxide, polypropylene oxide, copolymers thereof, etc.), polyglycerin (C ₃ Η ₆ O (CH ₂ CH (OH) CH ₂ O), and the like. ) N-H etc.), pyrrolidone, betaine (C _{3 ６ 6} N + Me ₂ —CH ₂ COO— etc.), sulfate (C ₃ H ₆ O (C ₂ H ₄ O) n—SO ₃ Na etc.), phosphoric acid (such as _{C 3 Η 6 O (C 2} H 4 O) n-P (= O) OHONa) salt, quaternary salt _{(C 3 H 6 n + Me} 3 Cl- , etc.). In the above chemical formula, n represents an integer of 1 or more.

  In addition, as the siloxane compound, other monomers copolymerizable with polydimethylsiloxane having a polymerizable vinyl group at the terminal (hydrophilic monomers such as (meth) acrylic acid and salts thereof are included in at least a part of the monomers). And vinyl copolymers having a silicone compound chain such as polydimethylsiloxane in the side chain obtained by copolymerization.

  Among these, as a siloxane compound, the compound which has a hydrophilic polymer chain in the compound which has a polysiloxane part is preferable. As the hydrophilic polymer chain, those containing a polyether bond are particularly preferred.

  Further, the siloxane compound is particularly preferably a nonionic surfactant having a structure of methylpolysiloxane in a hydrophobic group and polyoxyethylene in a hydrophilic group.

  The HLB (hydrophilic group / hydrophobic group balance) of the siloxane compound is preferably 8.0 or less. When the HLB of the siloxane compound is 8.0 or less, excellent ink drying properties can be secured at the time of ink jet printing on various non-penetrating media (recording media 40).

Here, HLB is defined by the following equation (Griffin method).
HLB = 20 × (sum of formula weight / molecular weight of hydrophilic part)

  Siloxane SAG005 (manufactured by Nissin Chemical Industry Co., Ltd .; HLB = 7.0) and Silface SAG008 (manufactured by Nissin Chemical Industry Co., Ltd .; HLB = 7.0) are preferably used as siloxane compounds. FZ2110 (Toray Dow Co., Ltd .; HLB = 1.0), FZ2166 (Toray Dow Co., Ltd .; HLB = 5.8), SH-3772M (Toray Dow Co., Ltd.) HLB = 6.0), L7001 (manufactured by Toray Dow Corp .; HLB = 7.4), SH-3773M (manufactured by Toray Dow Corp .; HLB = 8.0), KF-945 (Shin-Etsu) Chemical Industry Co., Ltd .; HLB = 4.0), KF-6017 (Shin-Etsu Chemical Co., Ltd .; HLB = 4.5), FormBan MS-575 (Ultra Addives Inc .; HLB = 5) .0) and the like.

  Said siloxane compound may be used independently and may be used in combination of 2 or more type. The total amount of the siloxane compound in the ink is preferably 0.1% by mass to 4.0% by mass, and more preferably 1.0% to 2.0% by mass. When the total amount of the siloxane compound in the ink is 1.0 to 2.0% by mass, the ink fixing property to various non-penetrable media (recording media 40) can be secured, and the image quality such as gloss is also good. is there.

<Resin particles>
The resin particles are not particularly limited. For example, polyester resin particles; polyurethane resin particles; epoxy resin particles; polyamide resin particles; polyether resin particles; acrylic resin particles; acrylic-silicone resin particles; Synthetic resin particles; polyolefin resin particles, polystyrene resin particles, polyvinyl alcohol resin particles, polyvinyl ester resin particles, polyacrylic acid resin particles, unsaturated carboxylic acid resin addition synthetic resin particles; celluloses, Examples thereof include natural polymers such as rosins and natural rubber. Two or more of the above resin particles may be used in combination.

  Among these resin particles, one of the resin particles to be added is preferably polyurethane resin particles from the viewpoints of ink dispersion stability and high gloss. Since the polyurethane resin particles have good dispersibility with the siloxane compound and the film-forming property is improved, good drying properties can be obtained, and color bleeding can be effectively suppressed. As a result, white border printing that forms an image using color ink after forming a background and / or background using white ink, and white post-printing that forms a background using white ink after forming an image using color ink, etc. Generation can be suppressed and a high-quality image can be obtained.

  In addition, as resin fine particles, what was synthesize | combined suitably may be used and a commercial item may be used.

<< Polyurethane resin particles >>
There is no restriction | limiting in particular as a polyurethane resin particle, For example, the polyurethane resin particle etc. which are obtained by making a polyol and polyisocyanate react are mentioned. Examples of the polyol include polyether polyol, polycarbonate polyol, and polyester polyol. These may be used alone or in combination of two or more.

-Polyether polyol-
Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as starting materials.

  Examples of starting materials include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolethane, Examples include trimethylolpropane. These may be used alone or in combination of two or more.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran. These may be used alone or in combination of two or more.

  Examples of the polyether polyol include polyoxytetramethylene glycol, polyoxypropylene glycol, and the like from the viewpoint of obtaining a binder for ink that can impart very excellent scratch resistance. These may be used alone or in combination of two or more.

-Polycarbonate polyol-
Moreover, as a polycarbonate polyol which can be used for manufacture of a polyurethane resin particle, the thing obtained by making carbonate ester and a polyol react, the thing obtained by making phosgene, bisphenol A, etc. react are mentioned, for example. These may be used alone or in combination of two or more.

  Examples of the carbonate ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, and the like. These may be used alone or in combination of two or more.

  Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2 -Butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcin, Bisphenol-A, bisphenol -F, 4,4'-biphenol and other relatively low molecular weight dihydroxy compounds, polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol and other polyether polyols, polyhexamethylene adipate, polyhexamethylene succinate, polycaprolactone, etc. And polyester polyols. These may be used alone or in combination of two or more.

-Polyester polyol-
Examples of polyester polyols include those obtained by esterifying low molecular weight polyols and polycarboxylic acids, polyesters obtained by ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, and copolymerized polyesters thereof. Etc. These may be used alone or in combination of two or more.

  Examples of the low molecular weight polyol include ethylene glycol and propylene glycol. These may be used alone or in combination of two or more.

  Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, anhydrides or ester-forming derivatives thereof. These may be used alone or in combination of two or more.

-Polyisocyanate-
Examples of polyisocyanates include aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate Examples thereof include aliphatic or alicyclic diisocyanates such as isocyanate and 2,2,4-trimethylhexamethylene diisocyanate. These may be used alone or in combination of two or more. Among these, aliphatic or alicyclic diisocyanates are preferable from the viewpoint of long-term weather resistance. This is because a coating film having a very high long-term weather resistance is required particularly when used for outdoor applications such as posters and billboards.

  Further, as the polyisocyanate, it is preferable to use at least one alicyclic diisocyanate since the coating film strength and scratch resistance can be obtained when an image is formed.

  Examples of the alicyclic diisocyanate include isophorone diisocyanate and dicyclohexylmethane diisocyanate. As content of alicyclic diisocyanate, 60 mass% or more is preferable with respect to the isocyanate compound whole quantity.

<< Method for Producing Polyurethane Resin Particles >>
The polyurethane resin particles can be obtained by a production method generally used conventionally. For example, the following method is mentioned. First, an isocyanate-terminated urethane prepolymer is produced by reacting a polyol and a polyisocyanate in an equivalent ratio in which an isocyanate group becomes excessive in the absence of a solvent or in the presence of an organic solvent. Next, the anionic group in the isocyanate-terminated urethane prepolymer is neutralized with a neutralizing agent as necessary, and then reacted with a chain extender, and finally the organic solvent in the system is removed as necessary. Can be obtained by:

  Examples of organic solvents that can be used for the production of polyurethane resin particles include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetates such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide Amides such as N-methylpyrrolidone and N-ethylpyrrolidone. These may be used alone or in combination of two or more.

  Examples of the chain extender include polyamines and other active hydrogen group-containing compounds. These may be used alone or in combination of two or more.

  Examples of polyamines include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 1,4-cyclohexanediamine. Diamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazines such as hydrazine, N, N′-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic dihydrazide, adipic acid dihydrazide, And dihydrazides such as glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide. These may be used alone or in combination of two or more.

  Examples of other active hydrogen group-containing compounds include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, and saccharose. , Glycols such as methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, hydroquinone ; Water etc. are mentioned. These may be used singly or in combination of two or more as long as the storage stability of the ink is not lowered.

  The polyurethane resin particles are preferably polycarbonate urethane resin particles from the viewpoint of high gloss. In the case of the polycarbonate-based urethane resin particles, it is possible to obtain an ink that maintains high gloss even for a recorded matter used in a harsh environment such as an outdoor use.

  As the polyurethane resin particles, commercially available products may be used. For example, U-coat UX-485 (polycarbonate-based urethane resin particles), U-coat UWS-145 (polyester-based urethane resin particles), Permarin UA-368T (polycarbonate-based urethane resin). Particles), permarin UA-200 (polyether-based urethane resin particles) (manufactured by Sanyo Chemical Industries, Ltd.), and the like. These may be used alone or in combination of two or more.

  Further, the volume average particle diameter of the resin particles is preferably 10 nm or more and 1,000 nm or less, more preferably 10 nm or more and 200 nm or less, and more preferably 10 nm or more, particularly considering use in the ink jet recording apparatus 1 which is a liquid ejection apparatus. 100 nm or less is particularly preferable.

  By using resin particles having a volume average particle diameter of 10 nm or more and 1,000 nm or less, excellent ink supply performance and ejection reliability when used in the inkjet recording apparatus 1 which is a liquid ejection apparatus having a circulation means for circulating ink. In addition, the resin particles easily dissolve in the organic solvent in the process of drying the ink on the printing material such as the non-penetrable medium (recording medium 40), and the effect of spreading the resin is easily obtained. Easy to form.

  The volume average particle diameter can be measured using, for example, a particle size analyzer (Microtrac Model UPA9340, manufactured by Nikkiso Co., Ltd.).

  When the resin particles are contained in the ink, the total content of the resin particles is preferably from 1% by mass to 15% by mass with respect to the total amount of the ink from the viewpoint of the dispersion stability of the ink, and the smoothness of the ink layer Is more preferable, and more preferably 5% by mass or more and 12% by mass or less and 5% by mass or more and 10% by mass or less from the viewpoint that the glossiness can be improved and high glossiness can be obtained and the fixability to the base material is improved.

The qualitative and quantitative determination of the resin particles can be confirmed, for example, by a procedure detailed in Reference Document 1 below. Specifically, it can be confirmed by analysis using a measurement apparatus as shown below.
[Reference 1]
"Testing method and evaluation results of each dynamic characteristic of plastic materials (22); Takeo Yasuda, Plastics: Journal of Japan Plastic Industry Federation /" Plastics "Editorial Board"

<< Infrared Spectroscopic Analysis (IR) >>
Infrared spectroscopic analysis (IR) can perform qualitative analysis of resin particles by measuring the absorption wavelength of various functional groups possessed by the resin particles and comparing it with the IR spectrum of known resin particles. Further, infrared spectroscopic analysis (IR) can compare the relative amounts of several types of monomers and resin particles by comparing the absorbance of the functional group absorption of each resin particle.

<< Thermal analysis (DS / A, TG / DTA) >>
Thermal analysis (DS / A, TG / DTA) is performed by measuring the melting point, glass transition point, etc. of resin particles using differential scanning calorimetry (DS / A) or differential thermal analysis (DTA). Can be identified.

<< Pyrolysis Gas Chromatography (PyGC) >>
Pyrolysis gas chromatography (PyGC) can separate pyrolysis products by gas chromatography and perform composition analysis and structural analysis. In the pyrolysis gas chromatography (PyGC), a more accurate analysis can be performed by directly connecting a mass spectrometer and identifying a decomposition product generated by pyrolysis.

<< Nuclear Magnetic Resonance (NMR) >>
The nuclear magnetic resonance method (NMR) can identify and confirm the resin particles in comparison with the spectrum of known resin particles. Nuclear magnetic resonance (NMR) can estimate the molecular structure in the case of unknown resin particles. Furthermore, the nuclear magnetic resonance method (NMR) can perform quantitative analysis of the composition ratio and blend ratio of a copolymer or a blend of a plurality of polymers.

  Before analyzing the resin particles using the measuring device as described above, the colorant component in the ink is precipitated by centrifugation as a pretreatment, and the supernatant containing the resin particles is collected or an appropriate organic material is collected. Extracting the resin particles using a solvent is also effective as a means for improving the analysis accuracy.

  Further, when heating is performed after recording by the ink jet recording apparatus 1 which is a liquid ejection apparatus, residual solvent can be reduced and adhesion can be improved. In particular, when the minimum film-forming temperature of the resin particles (hereinafter sometimes referred to as “MFT”) exceeds 80 ° C., heating is performed because there is no defective film-forming of the resin and image fastness is improved. preferable.

  When adjusting the minimum film-forming temperature of the resin emulsion, for example, the minimum film-forming temperature of the resin emulsion is adjusted by controlling the glass transition point of the resin (hereinafter sometimes referred to as “Tg”). Can do. Further, when the resin particles are a copolymer, the minimum film-forming temperature of the resin emulsion can be adjusted by changing the ratio of the monomers forming the copolymer. The minimum film-forming temperature refers to the minimum temperature at which a transparent continuous film is formed when the emulsion is thinly cast on a metal plate such as aluminum and the temperature is raised. The minimum film-forming temperature means that the emulsion becomes a white powder in a temperature range below the minimum film-forming temperature. Specifically, the minimum film-forming temperature is a commercially available minimum film-forming temperature measurement such as “film-forming temperature test device” (manufactured by Imoto Seisakusho Co., Ltd.), “TP-801 MFT tester” (manufactured by Tester Sangyo Co., Ltd.). The value measured by the device.

  Moreover, since it changes also by control of the particle diameter of resin, it is possible to make the minimum film forming temperature of resin into the target value by these control factors.

<Organic solvent>
There is no restriction | limiting in particular as an organic solvent, For example, a water-soluble organic solvent etc. are mentioned. Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 3 -Methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2 Polyhydric alcohols such as 1,6-hexanetriol, 2-ethyl-1,3-hexanediol, 1,2,4-butanetriol, 1,2,3-butanetriol, and petriol; ethylene glycol monoethyl ether, Ethylene glycol monobutyl ether, diethylene glycol Polyhydric alcohol alkyl ethers such as dimonomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether Polyhydric alcohol aryl ethers such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, etc. Heterocyclic compounds; Amides such as formamide, N-methylformamide, N, N-dimethylformamide; Monoethanolamine, Dieta Ruamin, amines such as triethylamine; dimethyl sulfoxide, sulfolane, sulfur-containing compounds such as thiodiethanol; propylene carbonate; ethylene carbonate. These may be used alone or in combination of two or more.

  Among these, from the viewpoint of high gloss and prevention of particle aggregation, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3- Butanediol, 2-methyl-2,4-pentanediol, and dipropylene glycol monomethyl ether are preferred. In addition, 1,2-propanediol and 1,2-butanediol having a boiling point of less than 200 ° C. are preferable from the viewpoint of promoting high scratch resistance, solvent resistance, and resin film formation.

  There is no restriction | limiting in particular as content of an organic solvent, 20 mass% or more and 70 mass% or less are preferable with respect to the ink whole quantity, and 30 mass% or more and 60 mass% or less are more preferable. When the content of the organic solvent is 20% by mass or more and 70% by mass or less, the drying property is excellent and good ejection stability is obtained.

<Compound>
The compound represented by the following general formula (1) accelerates the resin to form a film in the ink drying step, and thus can improve the drying property.
(In the general formula ^(1), R 1, ^{R 2,} and ^{R 3} each represents a an alkyl group having 1 to 5 carbon ^atoms, R 1, ^{R 2,} and ^{R 3} are the same May be different)

  Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a pentyl group.

  Examples of the compound represented by the general formula (1) include 3-methoxy-N, N-dimethylpropionamide represented by the following structural formula (1-1); represented by the following structural formula (1-2). 3-butoxy-N, N-dimethylpropionamide; 3-methoxy-N, N-diethylpropionamide and the like. These may be used alone or in combination of two or more. Among these, 3-methoxy-N, N-dimethylpropionamide represented by the following structural formula (1-1) is preferable from the viewpoints of adhesion, scratch resistance, non-transferability, and high gloss.

  By containing the compound represented by the general formula (1), the compatibility between the organic solvent and the resin particles can be increased, and the dispersibility can be improved. Further, the compound represented by the general formula (1) has high permeability to various non-penetrable media (recording medium 40), so that sufficient wettability to non-penetrable media (recording medium 40) is ensured. it can. As a result, it is possible to obtain an image having further excellent ink drying properties.

  In addition, the compound represented by the general formula (1) includes resin particles and 1,2-propanediol, 1,3-propanediol, 1,2- having a certain degree of affinity and a relatively low boiling point. By using an organic solvent such as butanediol, 1,3-butanediol, or 2,3-butanediol together, the dispersion stability of the resin particles in the ink can be secured, and the uniformity of the solid image portion after recording can be ensured. The image quality can be improved and excellent image quality can be obtained.

As a commercial item of the compound represented by the general formula (1), for example, trade name “Examide M-100” (manufactured by Idemitsu Kosan Co., Ltd., 3-methoxy-N, N-dimethylpropionamide, general formula (1) R ¹ : methyl group, R ² : methyl group, R ³ : methyl group), trade name “Ecamide B100” (made by Idemitsu Kosan Co., Ltd., 3-butoxy-N, N-dimethylpropionamide, general formula (1) ), R ¹ : methyl group, R ² : methyl group, R ³ : butyl group) and the like. These may be used alone or in combination of two or more.

  The total content of the compounds represented by the general formula (1) is preferably 5% by mass or more and 55% by mass or less, and more preferably 10% by mass or more and 45% by mass or less with respect to the total amount of the ink. When the total content of the compounds is 5% by mass or more and 55% by mass or less, the effect of uniform mixing is enhanced, and good ejection properties can be obtained when used in an ink jet printing method. Further, when the total content of the compounds is 5% by mass or more and 55% by mass or less, it becomes easy to produce an ink having excellent wettability to the non-permeable substrate.

  The content of at least one of the compounds represented by the general formula (1) in the ink can be confirmed by a gas chromatograph mass spectrometry (GCMS) method. Specifically, the entire ink is subjected to GCMS, and a qualitative analysis of the contained solvent is performed. Once the type of solvent can be identified, a calibration curve for the concentration of each solvent can be created to quantify each solvent contained in the ink.

<Water>
For the recording head 20 as the liquid discharge unit, it is possible to use a solvent ink that does not contain water, but it is also possible to use a water-based ink containing water as a highly safe ink that does not affect the environment. is there. There is no restriction | limiting in particular as water used for water-based ink, According to the objective, it can select suitably, For example, pure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water; Ultrapure water etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together.

  The water content is preferably 15% by mass or more and 60% by mass or less with respect to the total amount of ink. When the water content is 15% by mass or more, it is possible to prevent high viscosity and improve the discharge stability. When the water content is 60% by mass or less, the wettability to the non-permeable substrate becomes suitable. , Image quality can be improved.

<Other ingredients>
Examples of other components include coloring materials; antiseptic / antifungal agents; rust preventing agents; pH adjusting agents; rubbers such as hindered phenols and hindered phenol amines and colorless anti-aging agents for plastics.

<Color material>
White ink As a standard of whiteness of white ink, there is ISO-2469 (JIS-8148). Generally, when the value is 70 or more, it is used as a white color material. Examples of the color material used for the white ink include titanium oxide, iron oxide, tin oxide, zirconium oxide, and iron titanate (a composite oxide of iron and titanium).

Process color ink, special color ink As process color ink and special color ink, non-white ink such as color ink, black ink, gray ink, clear ink, metallic ink, etc. can be used. The clear ink means an ink that does not contain a colorant and mainly comprises resin particles, an organic solvent, and water. Examples of the color ink include cyan ink, magenta ink, yellow ink, light cyan ink, light magenta ink, red ink, green ink, blue ink, orange ink, and violet ink.

  The color material used for the non-white ink is not particularly limited as long as it exhibits a non-white color, and can be appropriately selected according to the purpose, and examples thereof include dyes and pigments. These may be used alone or in combination of two or more. Among these, a pigment is preferable. There is no restriction | limiting in particular as a coloring material used for a non-white ink, According to the objective, it can select suitably, A pigment, dye, etc. are mentioned. Among these, a pigment is preferable.

  Examples of the pigment include inorganic pigments and organic pigments. Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as a known method such as a contact method, a furnace method, and a thermal method. And carbon black. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the organic pigment include azo pigments (for example, azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, Quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (eg basic dye chelates, acidic dye chelates), nitro pigments, nitroso pigments, aniline black, etc. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together. In addition, use of hollow resin particles and inorganic hollow particles is also possible. Of these pigments, those having good affinity with the solvent are preferably used.

  Examples of the black pigment include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), and the like. Examples thereof include metals and organic pigments such as aniline black (CI Pigment Black 1). These may be used individually by 1 type and may use 2 or more types together.

  Examples of color pigments include C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155; I. Pigment orange 5, 13, 16, 17, 36, 43, 51; C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219; I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3 (phthalocyanine blue), 16, 17: 1, 56, 60, 63; I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142; I. Acid Red 52, 80, 82, 249, 254, 289; I. Acid Blue 9, 45, 249; C.I. I. Acid Black 1, 2, 24, 94; C.I. I. Food black 1, 2; I. Direct yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173; I. Direct Red 1, 4, 9, 80, 81, 225, 227; I. Direct blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202; I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195; I. Reactive red 14, 32, 55, 79, 249; I. Reactive black 3, 4, 35 etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

  The color material used in the metallic ink is, for example, a fine powder obtained by finely pulverizing a metal simple substance, an alloy, or a metal compound. More specifically, the color material used for the metallic ink is any one of a group of simple metals made of aluminum, silver, gold, nickel, chromium, tin, zinc, indium, titanium, silicone, copper, or platinum. Or an alloy obtained by combining a plurality of these metals or a group of these metals, or any of oxides, nitrides, sulfides, or carbides of a single metal or an alloy of these groups. It is obtained by pulverizing one kind or plural kinds.

  In addition, a self-dispersing pigment that can be dispersed in water by adding a functional group such as a sulfone group or a carboxyl group to the surface of the pigment (for example, carbon black) can be used. Further, it may be a resin fine particle containing a pigment in a microcapsule and capable of dispersing the pigment in water, that is, a resin particle containing pigment particles. In this case, the pigment contained in the ink is not necessarily sealed or adsorbed in the resin fine particles, and the pigment may be dispersed in the ink.

  The number average particle diameter of the pigment is not particularly limited, and the maximum frequency in terms of the maximum number is preferably 20 nm or more and 150 nm or less. When the number average particle diameter is 20 nm or more, the dispersion operation and classification operation are facilitated. When the number average particle diameter is 150 nm or less, not only the pigment dispersion stability as the ink composition is improved, but also the ejection stability is excellent. The image quality such as the image density is also high, which is preferable. The number average particle diameter can be measured using, for example, a particle size analyzer (Microtrac Model UPA9340, manufactured by Nikkiso Co., Ltd.).

  In the case of dispersing a pigment using a dispersant, any conventionally known pigment can be used, and examples thereof include a polymer dispersant and a water-soluble surfactant. These may be used alone or in combination of two or more.

<Antiseptic and fungicide>
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
Examples of the rust inhibitor include 1,2,3-benzotriazole.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

<Ink production method>
As an ink production method, for example, water, an organic solvent, a compound represented by the general formula (1), resin particles, and, if necessary, other components are dispersed or dissolved in an aqueous medium, and appropriately stirred and mixed. Can be manufactured. As the stirring and mixing, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, a stirrer using a normal stirrer blade, a magnetic stirrer, a high-speed disperser, or the like can be used.

<Viscosity>
The viscosity of the ink is preferably 2 mPa · s or more and more preferably 3 mPa · s or more and 20 mPa · s or less at 25 ° C. from the viewpoint of image quality such as character quality when recorded on a printing medium. When the viscosity is 2 mPa · s or more, ejection stability can be improved.

<Ink cartridge>
The ink cartridge includes an ink cartridge that stores process color ink, special color ink, and auxiliary ink in a container. The ink cartridge contains ink in a container and further includes other members appropriately selected as necessary.

  The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, at least an ink bag formed of an aluminum laminate film, a resin film or the like can be used. And the like.

<Recorded material>
The recorded matter has an image recorded with ink on a recording medium.

<Recording medium>
There is no particular limitation on the recording medium, and plain paper, glossy paper, special paper, cloth, etc. can be used, but good image formation is possible even with non-penetrable media (recording medium 40) as described above. It is. Non-penetrable media (recording media 40) is a base material having a surface with low water permeability and absorbency, and includes materials that do not open to the outside even though there are many cavities inside, and are more quantitative. Specifically, it refers to a substrate having a water absorption of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method.

  As the non-penetrable medium (recording medium 40), for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, polypropylene, polyethylene, or a polycarbonate film can be preferably used.

  The recording medium is not limited to that used as a general recording medium, and wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather, etc. can be used as appropriate. . Moreover, ceramics, glass, metal, etc. can also be used by adjusting the structure of the path | route which conveys a recording medium.

<Example of ink>
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “part” is “part by mass”, and “%” is “% by mass”.

<< Preparation of polycarbonate urethane resin emulsion >>
Into a reaction vessel into which a stirrer, a reflux condenser and a thermometer were inserted, 1,500 g of polycarbonate diol (reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1200)), 2,2-di Methylolpropionic acid (hereinafter sometimes referred to as “DMPA”) (220 g) and N-methylpyrrolidone (hereinafter also referred to as “NMP”) (1,347 g) were charged in a nitrogen stream and heated to 60 ° C. DMPA was dissolved.

  Next, 1,445 g of 4,4′-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction for 5 hours to obtain an isocyanate-terminated urethane prepolymer. It was. The reaction mixture was cooled to 80 ° C., 4,340 g was extracted from the mixture in which 149 g of triethylamine was added and mixed, and added to a mixed solution of 5,400 g of water and 15 g of triethylamine with vigorous stirring. Next, 1,500 g of ice was added, 626 g of 35% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction, and the solvent was distilled off so that the solid concentration was 30%. A polycarbonate urethane resin emulsion was obtained.

  The minimum film-forming temperature measured with a “film-forming temperature test apparatus” (manufactured by Imoto Seisakusho Co., Ltd.) using a polycarbonate urethane resin emulsion was 55 ° C.

<< Preparation of polyether urethane resin emulsion >>
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 100.2 parts of polyether polyol ("PTMG1000" manufactured by Mitsubishi Chemical Corporation, average molecular weight: 1,000), 2,2- 15.7 parts of dimethylolpropionic acid, 48.0 parts of isophorone diisocyanate, 77.1 parts of methyl ethyl ketone as the organic solvent, and 0.06 part of dibutyltin diureate (hereinafter sometimes referred to as “DMTDL”) as the catalyst And reacted.

  After the reaction was continued for 4 hours, 30.7 parts of methyl ethyl ketone was supplied as a diluent solvent, and the reaction was further continued.

  When the average molecular weight of the reactant reached a range of 20,000 to 60,000, 1.4 parts of methanol was added to complete the reaction, thereby obtaining an organic solvent solution of urethane resin.

  The carboxyl group of the urethane resin is neutralized by adding 13.4 parts of a 48% aqueous potassium hydroxide solution to the organic solvent solution of the urethane resin, and then 715.3 parts of water is added and stirred sufficiently, followed by aging and desorption. By making the solvent, a polyether urethane resin emulsion having a solid content of 30% by mass was obtained.

  For the polyether-based urethane resin emulsion, the minimum film-forming temperature measured with a “film-forming temperature test apparatus” (manufactured by Imoto Seisakusho Co., Ltd.) in the same manner as in the preparation of the polycarbonate-based urethane resin emulsion was 43 ° C.

<< Preparation of polyester urethane resin emulsion >>
Except for changing the polyether polyol ("PTMG1000" manufactured by Mitsubishi Chemical Corporation, average molecular weight: 1,000) to a polyester polyol ("Polylite OD-X-2251" manufactured by DIC Corporation, average molecular weight: 2,000). A polyester urethane resin emulsion having a solid content of 30% by mass was obtained in the same manner as in Preparation Example 2 of the polyether urethane resin emulsion.

  For the polyester-based urethane resin emulsion, the minimum film-forming temperature measured with a “film-forming temperature test apparatus” (manufactured by Imoto Seisakusho Co., Ltd.) in the same manner as in the preparation of the polycarbonate-based urethane resin emulsion was 74 ° C.

<< Preparation of acrylic resin emulsion >>
A reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer was charged with 900 g of ion-exchanged water and 1 g of sodium lauryl sulfate, and the temperature was raised to 70 ° C. while purging with nitrogen under stirring. Maintaining the internal temperature at 70 ° C., adding 4 g of potassium persulfate as a polymerization initiator, dissolving, and previously stirring 450 g of ion exchange water, 3 g of sodium lauryl sulfate, 20 g of acrylamide, 615 g of styrene, 30 g of butyl acrylate, and 350 g of methacrylic acid The emulsion prepared in addition to the chemical conversion was continuously dropped into the reaction solution over 4 hours. After completion of the dropwise addition, the mixture was reacted for 3 hours to obtain an aqueous emulsion.

  The obtained aqueous emulsion was cooled to room temperature, and then ion exchange water and an aqueous sodium hydroxide solution were added to obtain an acrylic resin emulsion having a solid content of 30% by mass and a pH of 8.

  For the acrylic resin emulsion, the minimum film-forming temperature measured with a “film-forming temperature test apparatus” (manufactured by Imoto Seisakusho Co., Ltd.) was 53 ° C. in the same manner as in the preparation of the polycarbonate urethane resin emulsion.

<Preparation of pigment dispersion>
<< Preparation of Black Pigment Dispersion >>
The following prescription mixture was premixed and then circulated and dispersed for 7 hours in a disk type bead mill (Shinmaru Enterprises KDL type, media: 0.3 mm diameter zirconia ball used) to obtain a black pigment dispersion.
Carbon black pigment (trade name: Monarch 800, manufactured by Cabot) · 15 parts Anionic surfactant (Pionin A-51-B, manufactured by Takemoto Yushi Co., Ltd.) ··· 2 parts Ion-exchanged water ···・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 83 parts

<< Preparation of Cyan Pigment Dispersion >>
A cyan pigment dispersion was obtained in the same manner as the black pigment dispersion except that the carbon black pigment was changed to Pigment Blue 15: 3 (trade name: LIONOL BLUE FG-7351, manufactured by Toyo Ink Co., Ltd.). .

<< Preparation of magenta pigment dispersion >>
A magenta pigment dispersion was obtained in the same manner as the preparation of the black pigment dispersion, except that the carbon black pigment was changed to Pigment Red 122 (trade name: Toner Magenta EO02, manufactured by Clariant Japan Co., Ltd.).

<< Preparation of Yellow Pigment Dispersion >>
A yellow pigment dispersion was obtained in the same manner as the preparation of the black pigment dispersion, except that the carbon black pigment was changed to Pigment Yellow 74 (trade name: First Yellow 531; manufactured by Dainichi Seika Kogyo Co., Ltd.).

<< Preparation of white pigment dispersion >>
Titanium oxide (trade name: STR-100W, manufactured by Sakai Chemical Industry Co., Ltd.) 25 parts, pigment dispersant (trade name: TEGO Dispers 651, manufactured by Evonik Co., Ltd.) 5 parts, and water 70 parts are mixed, and a bead mill (trade name: Research). (Lab, manufactured by Shinmaru Enterprises Co., Ltd.) 0.3 mmφ zirconia beads were dispersed for 5 minutes at a filling rate of 60% and 8 m / s to obtain a white pigment dispersion.

<Preparation of black ink 1>
Black pigment dispersion 20% by mass, polycarbonate urethane resin emulsion (solid content concentration 30% by mass) in terms of resin solid content 10% by mass, 1,2-propanediol 12% by mass, 1,2-butanediol 5% by mass , 3-methoxy-N, N-dimethylpropionamide (trade name: Ecamide M-100, manufactured by Idemitsu Kosan Co., Ltd.) 17% by mass, siloxane compound (trade name: FZ2110, manufactured by Toray Dow Co., Ltd., HLB = 1.0) 1%, Trade name: Proxel LV (manufactured by Avicia Co., Ltd.) 0.1% by mass, and 12% by mass of high-purity water are mixed and stirred, and filtered through a 0.2 μm polypropylene filter to obtain a black ink. 1 was produced.

<Preparation of inks 2 to 6>
Inks 2 to 6 were prepared in the same manner as the black ink 1 except that the ink compositions and contents shown in Table 1 shown below were changed. Table 1 shows the compositions and contents of inks 1 to 6.

  Using the recording head 20 as a liquid ejection unit and the inkjet recording apparatus 1 as a liquid ejection device, white front printing for forming an image with color ink after forming a background and background with white ink, and using white ink after forming an image with color ink White post-printing and the like for forming a background by providing a white ink layer were performed. The evaluation results are as shown in Table 2 below. As the recording medium 40, PVC (Polyvinyl chloride) was used. In Examples 1 to 9 shown in Table 2, the inks 1 to 5 were used as color inks, and the ink 6 was used as a white ink. In Example 10 shown in Table 2, a commercially available RICOH Pro ink was used as the ink.

As shown in the evaluation results of Table 2, a high-quality image without bleeding (bleeding) as shown in FIG. 10 could be obtained at all mass boundaries at a productivity of 50 m ² / h (in the evaluation results). , ◎). In addition, at a productivity of 45 m ² / h, a high-quality image without bleeding (bleeding) as shown in FIG. 10 could be obtained at all the cell boundaries (indicated by a circle in the evaluation result). Furthermore, at a productivity of 40 m ² / h, a high-quality image having no bleeding (bleeding) as shown in FIG. 10 could be obtained at all mass boundaries (indicated by Δ in the evaluation result).

DESCRIPTION OF SYMBOLS 1 Liquid discharge apparatus 2 Image formation part 3,80 Drying apparatus 4 Media storage part 5 Conveyance mechanism 10 Control part 20 Liquid discharge unit 20a 1st nozzle group 20b 2nd nozzle group 20c 3rd nozzle group

JP 2006-167934 A

Claims (12)

A first nozzle group having a nozzle array in which a plurality of nozzle holes for discharging a process color liquid for image formation are arranged in a sub-scanning direction orthogonal to the main scanning direction;
Provided upstream and downstream in the sub-scanning direction with respect to the first nozzle group, the first nozzle group is disposed so as to be shifted in the main scanning direction from each other, and a liquid having a color different from the process color is provided. A second nozzle group and a third nozzle group having nozzle rows in which a plurality of nozzle holes to be ejected are arranged in the sub-scanning direction;
A liquid discharge unit comprising: The first nozzle group, the second nozzle group, and the third nozzle group have the same number of nozzle rows and the same number of nozzles.
The liquid discharge unit according to claim 1. The first nozzle group, the second nozzle group, and the third nozzle group are integrally mounted.
The liquid discharge unit according to claim 1, wherein the liquid discharge unit is a liquid discharge unit. The first nozzle group includes nozzle rows that eject black, yellow, magenta, and cyan inks as the process color liquid,
The second nozzle group and the third nozzle group have a nozzle row that discharges auxiliary ink having a color different from the process color as the liquid.
The liquid ejection unit according to claim 1, wherein the liquid ejection unit is a liquid ejection unit. The second nozzle group and the third nozzle group have nozzle rows that respectively discharge the auxiliary ink and the special color ink for image formation that are different from the process color.
The liquid discharge unit according to claim 4. The liquid includes water, an organic solvent, a color material, resin particles, and a siloxane compound.
The liquid discharge unit according to claim 1, wherein the liquid discharge unit is a liquid discharge unit. The resin particles are polyurethane resin particles.
The liquid discharge unit according to claim 6. The polyurethane resin particles are polycarbonate urethane resin particles or polyester urethane resin particles,
The liquid discharge unit according to claim 7. The organic solvent includes a compound represented by the following general formula (1),
The liquid discharge unit according to claim 6, wherein the liquid discharge unit is a liquid discharge unit. A media storage section for storing recording media;
A transport mechanism for transporting the recording medium stored in the media storage unit;
10. The liquid discharge unit according to claim 1 is mounted, and liquid is discharged while the liquid discharge unit is reciprocated in the main scanning direction with respect to the recording medium transported by the transport mechanism. An image forming unit that forms a required image
A drying device for drying an image formed by the image forming unit;
A liquid ejection apparatus comprising: Formed by ejecting a liquid of a color different from the process color to an image layer that is an image layer formed by ejecting a process color liquid for image formation to the nozzle row of the liquid ejection unit. A control unit for controlling the auxiliary layer, which is an auxiliary layer, to be arranged as any one of pre-printing, post-printing, and inter-printing,
The liquid ejecting apparatus according to claim 10. In the printing method printed using the liquid discharge device according to claim 10 or 11,
As a process color liquid for image formation, black ink, yellow ink, magenta ink, cyan ink are ejected from the liquid ejection device,
As the black ink, yellow ink, magenta ink, and cyan ink, water, a color material, a siloxane compound, an ink having a compound represented by the following general formula (1) and polyurethane resin particles are used.
A printing method characterized by the above.