JP2006272962A - Image formation apparatus and droplet control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image formation apparatus which can prevent image deformation caused by overlapped dots with short recording time. <P>SOLUTION: An organic pigment solvent dissolved in an aqueous solvent is caused to pass through a channel as a laminar flow. In the laminar flow process, droplets including organic pigment fine particles generated in the process of changing the hydrogen-ion exponent of the solution are discharged, thereby forming a first dot 102 and a second dot 112 so that they are overlapped with each other. First, an ink droplet 100 having a diameter D1a which forms the first dot 102 is discharged. When a predetermined time is elapsed, the ink droplet 100 is permeated into the recording paper, and the diameter on the recording paper surface becomes D1b. When the ink droplet 110 which forms the second dot 112 is discharged in this state, the ink droplet 100 and the ink droplet 110 are not mixed with each other. Moreover, mixture of the inks does not occur also in the recording paper since ink permeated into the recording paper is retained in an image receiving layer in the recording paper. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a droplet ejection control method, and more particularly to an image forming apparatus that forms an image with dots formed on a recording medium with an organic pigment ink and a recording control technique in the droplet ejection control method.

  In recent years, inkjet recording apparatuses (inkjet printers) have become widespread as recording apparatuses that print and record images taken by digital still cameras. An ink jet recording apparatus includes a plurality of recording elements (nozzles) in a head, and scans the recording head while ejecting ink droplets from the recording elements onto the recording medium to record an image for one line on the recording medium. The recording medium is conveyed by one line, and this process is repeated to form an image on the recording paper.

  Ink jet printers use a single serial head and perform recording while scanning the head in the width direction of the recording medium, and recording elements are arranged corresponding to the entire area of one side of the recording medium. Some use a line head. In the case of using a line head, image recording can be performed on the entire surface of the recording medium by scanning the recording medium in a direction orthogonal to the arrangement direction of the recording elements. A printer using a line head does not require a transport system such as a carriage that scans a short head, and does not require complicated scanning control between the carriage movement and the recording medium. In addition, since only the recording medium moves, the recording speed can be increased as compared with a printer using a serial head.

  In an inkjet printer, one image is expressed by combining dots formed by ink ejected from a recording element (nozzle). High image quality is achieved by reducing the size of these dots and increasing the number of pixels per image. Since the dot size can be reduced by reducing the ink discharge amount, it is necessary to control the ink discharge amount finely and accurately. Further, the relative speed between the recording medium and the recording head and the ink ejection timing are controlled so that adjacent dots are ejected at a predetermined droplet ejection position.

  The ink jet recording apparatus disclosed in Patent Document 1 calculates the time during which no image distortion occurs from the ink absorption characteristics, ink penetration characteristics, ink (dot) density, ink volume, ink evaporation characteristics, and environmental temperature. Techniques to do this have been proposed. That is, the ink drying time and the like are estimated from the parameters described above, and the interval between recordings is adjusted.

  A method and a printing method for manufacturing a recording head for an ink jet printer described in Patent Document 2 include a method for manufacturing a print head by determining a distance between nozzles in consideration of an ink drying time, and a method for using the print head. A printing method that has been proposed has been proposed.

  On the other hand, ink for ink jet printers can be broadly classified into dye ink and pigment ink. Dye has been used as a coloring material for ink jet ink, but dye ink is difficult in terms of water resistance and light resistance. In order to improve it, pigments are being used. However, the image obtained with the pigment ink has a remarkable advantage in light resistance and water resistance as compared with the image with the dye ink, but on the other hand, the pigment has a nanometer size that can penetrate into the voids on the paper surface. There is a problem that uniform miniaturization (that is, monodispersion) is difficult, and images with high saturation cannot be obtained due to lack of permeability to paper.

As a countermeasure against this, Patent Document 3 proposes a method of making pigment fine particles using a microjet reactor method. In this method, a solution in which a pigment is dissolved and a precipitation medium liquid are pumped into two nozzles of different micrometer sizes facing each other at high pressure (for example, 5 MPa). In this method, air is introduced vertically, and the pigment suspension is discharged with the gas flow (about 0.5 m ³ / h).
JP-A-3-247450 Japanese Patent Laid-Open No. 10-250059 JP 2002-146222 A

  By the way, in image formation of an ink jet printer, when a plurality of dots are overlapped and landed on a recording medium, ink droplets are mixed, and the original circular shape of the dot shape collapses (occurrence of landing interference), There is a problem that it is difficult to form a desired high-definition image.

  However, Patent Document 1 and Patent Document 2 cannot solve the problem of landing interference. In particular, when pigment ink is used as the ink, the saturation of pigment fine particles having a large particle diameter and poor monodispersibility is demonstrated. There is a concern that not only high-quality images cannot be obtained, but also landing interference is promoted.

  That is, in the ink jet recording apparatus disclosed in Patent Document 1, the time during which no image disturbance occurs is obtained for each parameter, but it is very difficult to obtain the time during which image disturbance does not occur for various dot arrangement patterns. It is. Also, a recording method for forming mixed patterns with different dot pitches and dot diameters in one image is not sufficiently disclosed.

  Moreover, in the method and the printing method for manufacturing a recording head for an ink jet printer described in Patent Document 2, it is disclosed that the second dot is landed after the drying time of the first dot has elapsed, Adjacent dots cannot be landed until the dots on the surface of the paper are completely dried, and it takes a very long time for printing. Further, since the distance between the nozzles is determined assuming a drying time based on one condition and is set to a fixed value, it is not possible to cope with a change in ink or paper.

  Further, the pigment described in Patent Document 3 is devised so as to prevent particles from being blocked by pigment fine particles by generating particles in a micrometer-scale small space and immediately taking them out of the device. Although it is preferable to obtain fine particles with a diameter distribution, it is difficult to control the contact time between the two liquids, so it is difficult to control fine reactions, so it is difficult to stably produce fine pigment particles with excellent monodispersibility. There is a problem.

  As described above, conventionally, there are problems that have not yet been solved in terms of measures for preventing landing interference and measures for miniaturizing pigment particles, and it is difficult to obtain high-definition images with high saturation with pigment ink. there were.

  The present invention has been made in view of such circumstances, and can prevent droplets of a pigment ink containing fine pigment particles containing fine pigment particles having excellent monodispersibility from a recording head, and also prevent image disturbance due to overlapping dots. In addition, since it is possible to perform droplet ejection control that does not require recording time, an image forming apparatus and a droplet ejection control method capable of obtaining high-definition images with high saturation and high-speed droplet ejection with pigment ink are provided. The purpose is to provide.

  In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that a solution of an organic pigment dissolved in an alkaline or acidic aqueous medium is circulated as a laminar flow in a flow path on a recording medium, And a recording head for ejecting droplets containing organic pigment fine particles produced by the step of changing the hydrogen ion index (pH) of the ink.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors synthesized organic pigments by circulating a solution containing reaction components in a flow channel (channel). It was found that an organic pigment was obtained. In addition, compared with the conventional method in which a solution of organic pigment is used in a flask by carrying out a coprecipitation method (reprecipitation method) under the influence of pH change in a flow path where the laminar flow is dominant. It has been found that fine organic pigment particles having finer particle diameters and good monodispersibility can be obtained.

  In this way, by ejecting a pigment ink composed of fine organic pigment fine particles having a fine particle diameter from a recording head, not only the permeability to a recording medium is improved, but also the droplet ejection interference is suppressed. Therefore, it is possible to obtain a high-definition image with high saturation. Further, the clogging of the nozzles of the recording head can be greatly reduced as compared with the conventional pigment ink.

  In particular, in a two-liquid agglomeration reaction-type image forming apparatus, in which an ink using a pigment as a color material and a treatment liquid that agglomerates and reacts with a pigment are deposited or adhered, the monodisperse By using a pigment ink composed of fine organic pigment fine particles, the pigment aggregates instantaneously and settles on the recording medium, and the shape of the pigment is maintained even if the ink solvents mix and coalesce. It is more effective in preventing.

  In order to achieve the above-mentioned object, the invention according to claim 2 is characterized in that a solution of an organic pigment dissolved in an alkaline or acidic aqueous medium is circulated in a flow path as a laminar flow on a recording medium, A recording head for ejecting droplets containing organic pigment fine particles produced by the step of changing the hydrogen ion index (pH) of the ink, droplet ejection control means for controlling the ejection timing of the recording head, and the recording medium And a conveying means for moving the recording head relative to the recording medium, wherein the first dots formed on the recording medium and the first dots are formed on the recording medium. The interval Pt between the second dot formed so as to overlap the first dot after the first droplet is deposited, and the time when the second droplet forming the second dot is landed on the recording medium Recording medium table in When the second droplet reaches the recording medium, and the diameter D1b of the first droplet on the surface of the recording medium is D1b <2 × Pt -The droplet diameter change time until the diameter D1b of the first droplet satisfying D2a is set as the droplet ejection interval from the droplet ejection of the first droplet to the droplet ejection of the second droplet It is characterized by controlling droplet timing.

  That is, even if the second droplet is landed on the recording medium without waiting until the first droplet landed on the recording medium is completely held on the recording medium, the surface of the recording medium Ink mixing does not occur. Therefore, it is possible to prevent bleeding due to the mixing of the first droplet and the second droplet without reducing the printing speed, and a desired dot shape can be obtained.

  For example, in the process in which droplets penetrate into the recording medium, the droplets on the surface of the recording medium become smaller from the outside (outer periphery) toward the inside. The droplet size when landing on the recording medium is substantially the same as the size of the dots formed.

  The interval (dot pitch interval) Pt between the first dot and the second dot is substantially the same as the interval between the droplets ejected (recorded) normally from the recording head.

In addition, D1b = 0 when the first droplet has completely penetrated, solidified, etc., so that the state where the first ink droplet does not completely penetrate satisfies D1b> 0.

  When the first dot and the second dot overlap, the sum of the radius of the first dot (D1a / 2) and the radius of the second dot (D2a / 2) is the first dot and the second dot. This is a case where the distance Pt is larger than the distance Pt between the two dots, and this satisfies the relationship Pt <(D1a / 2) + (D2a / 2).

  The recording head may be a full-line type recording head in which recording elements such as ink ejection holes are arranged over the entire printable area of the recording medium used in a direction substantially perpendicular to the relative conveying direction of the conveying means, A serial type (shuttle scan type) recording head that ejects ink droplets while moving a short recording head in a direction substantially orthogonal to the relative conveying direction of the conveying means may be used.

  A recording medium is a medium (image forming medium) that receives printing by a recording head. Specifically, a continuous sheet, a cut sheet, a sealing sheet, a resin sheet such as an OHP sheet, a film, a cloth, and other materials and shapes are used. Regardless, it includes various media.

  As a mode in which the recording medium and the recording head are relatively moved, the recording medium may be moved relative to the fixed recording head, or the recording medium may be fixed and the recording head may be moved. Further, both the recording medium and the recording head may be moved. A conveying belt, a conveying drum, or the like is applied to the recording medium conveying means.

  Thus, according to the invention of claim 2, pigment ink containing pigment fine particles having a fine particle diameter and excellent monodispersibility can be ejected from the recording head, and image disturbance due to overlapping of dots can be prevented. Since droplet ejection control that does not require recording time can be performed, it is possible to obtain a high-definition image with high saturation using pigment ink.

  According to a third aspect of the present invention, in the invention described in the second aspect, an interval Pt between the first dot and the second dot, and the recording medium when the second droplet is landed on the recording medium The droplet ejection condition calculation means for obtaining the diameter D1b of the first droplet satisfying the following equation: D1b <2 × Pt−D2a, and the first droplet landed on the recording medium. And a droplet diameter change time calculating means for obtaining a droplet diameter change time from the first droplet until the diameter of the first droplet reaches D1b.

  That is, a droplet ejection condition calculating means for obtaining a condition of the first droplet capable of ejecting the second droplet, and a droplet diameter for obtaining a time until the first droplet satisfies the condition Since the change time calculation means is provided, the droplet ejection interval can be obtained efficiently in the apparatus.

  As described in claim 4, in the invention described in claim 3, a mixed pattern having a plurality of combinations of the dot interval, the diameter of the first dot, and the diameter of the second dot is formed in one image. In this case, a plurality of droplet diameter change times are calculated, and the droplet ejection control means controls the recording timing of the image using the calculated representative values of the plurality of droplet diameter change times. .

  That is, it is possible to cope with an image including a mixed pattern in which the dot interval (dot pitch) and the diameter of each dot are different, and the droplet ejection timing can be optimized for each image.

  The mixed pattern includes a plurality of dot intervals, a plurality of dot diameters, and a plurality of dot intervals and dot diameters.

  The representative value includes a maximum value, a minimum value, an average value, a value that is used most frequently, and the like, and may be appropriately used according to image quality and recording control. One representative value may be obtained per image, or a plurality of representative values may be obtained per image.

  Further, as shown in claim 5, in the invention according to claim 4, the representative value of the droplet diameter change time is at least a plurality of droplet diameter change times calculated by the droplet diameter change time calculation means. It is characterized by containing values that are greater than the maximum value.

  In other words, since the droplet ejection timing in the image is controlled in accordance with the pattern with the longest droplet diameter change time, it is possible to reliably prevent dot bleeding, and the control system is simple and the burden on the control system is reduced. To do.

  The droplet diameter change time may be a maximum value obtained from each pattern, or may be a time obtained by adding a margin to the maximum value in anticipation of safety. However, the droplet diameter change time is less than the time when the penetration or solidification of the droplet is completely completed.

  Moreover, as shown in claim 6, in the invention according to any one of claims 2 to 5, the droplet ejection control means controls the droplet ejection timing by one droplet ejection interval in one image. It is characterized by.

  That is, since droplet ejection control is performed by one droplet ejection interval within one image, it is possible to have a droplet ejection interval for each image.

  According to a seventh aspect of the present invention, in the invention according to any one of the third to sixth aspects, information including at least one of the liquid type information and the recording medium type information is included. Provided with information providing means for providing, wherein the droplet diameter change time calculating means calculates the droplet diameter change time based on information provided by the information providing means.

  That is, even if the type of liquid or the type of recording medium (recording paper) changes, recording (image formation) is performed at the optimum droplet ejection timing, so that not only the printing speed is high but also a desired dot shape is obtained. Can do.

  In addition to the type of ink and the type of recording medium, the information may include factors that may affect environmental conditions such as temperature and humidity and the ink penetration rate. It is preferable that these conditions are converted into a data table and the data table is referred to when the droplet diameter change time is obtained.

  In addition, as shown in claim 8, in the invention according to any one of claims 3 to 7, the droplet diameter change time calculating means includes dots in a direction substantially perpendicular to the relative carrying direction of the carrying means. From the pitch and the dot pitch in the relative transport direction of the transport means, the first droplet diameter change time in the direction substantially perpendicular to the relative transport direction of the transport means and the second droplet diameter in the relative transport direction of the transport means A change time is obtained, and the droplet ejection control means sets the first droplet diameter change time and the second droplet diameter change time to a droplet ejection interval in a direction substantially perpendicular to the relative conveyance direction of the conveyance means, and The droplet ejection timing is controlled as a droplet ejection interval in the sub-scanning direction, which is the relative conveyance direction of the conveyance means.

  That is, it is possible to control the droplet ejection timing in the direction (main scanning direction) substantially orthogonal to the relative conveyance of the conveyance unit and the relative conveyance direction (sub-scanning direction) of the conveyance unit.

  Further, as shown in claim 9, in the invention according to any one of claims 2 to 8, the recording head has a plurality of nozzles arranged over a length corresponding to the entire width of the recording medium. It is a line head.

  The line head may be a divided head that is divided into a plurality of heads in the longitudinal direction of the head. Further, the head may include one nozzle row or a plurality of nozzle rows.

  According to a tenth aspect of the present invention, in the invention according to the ninth aspect, the recording head forms odd-numbered dots among dots formed along a direction substantially perpendicular to the relative conveyance direction of the conveyance means. A first nozzle row having nozzles for ejecting liquid droplets and a second nozzle row having nozzles for ejecting liquid droplets that form even-numbered dots, and a relative transport direction of the transport means It is characterized by comprising an interval varying means for varying the interval between the first nozzle row and the second nozzle row in accordance with the droplet ejection control.

  That is, in the line head, the recording timing in the direction substantially orthogonal to the recording medium can be controlled efficiently.

  Further, as shown in claim 11, in the invention according to any one of claims 2 to 8, the recording head has a plurality of nozzles arranged over a length shorter than the entire width of the recording medium. The serial head includes a moving means for moving the recording head and the recording medium relative to each other along the nozzle arrangement direction.

  According to a twelfth aspect of the present invention, in the invention according to the eleventh aspect, the recording head forms odd-numbered dots among dots formed along a direction substantially orthogonal to the relative transport direction of the transport means. A first nozzle row having nozzles for ejecting liquid droplets and a second nozzle row having nozzles for ejecting liquid droplets that form even-numbered dots, and a relative transport direction of the transport means And an interval varying means for varying the interval between the first nozzle row and the second nozzle row in accordance with droplet ejection control in a direction substantially orthogonal to the first nozzle row.

  That is, it is possible to control the recording timing in the direction substantially orthogonal to the recording medium without changing the conveyance speed and the recording frequency.

  Further, as shown in claim 13, in any one of claims 1 to 12, the organic pigment fine particles are produced by a solution of an organic pigment containing at least one dispersant.

  In other words, the organic pigment fine particles are produced from a solution of an organic pigment containing at least one dispersant, whereby organic pigment fine particles having a fine particle size of nano-size level and excellent monodispersibility can be obtained. In addition to improving the degree of penetration and improving the permeability to the recording medium, it is possible to further suppress the droplet ejection interference.

  In addition, as shown in claim 14, in the invention described in any one of claims 1 to 13, the organic pigment fine particles have a mode diameter of 1 μm or less.

  When the mode diameter is 1 μm or less, it means that there is no variation in the chemical composition and crystal structure in the organic pigment fine particles, so that the physical properties of the organic pigment fine particles are constant, and the pigment ink has high saturation. A fine image can be further obtained.

Further, as shown in claim 15, in the invention according to any one of claims 1 to 14, the organic pigment fine particles are quinacridone type represented by the general formula (I), wherein the organic pigment solution is alkaline. It is characterized by being a pigment.

  The fifteenth aspect is preferably a quinacridone pigment among the pigments used in the pigment ink, and the quinacridone pigment is used to form fine particles.

  According to a sixteenth aspect of the present invention, in the invention according to any one of the first to fifteenth aspects, the liquid droplets ejected from the recording head are alkaline, and at least the liquid of the liquid droplets of the recording head. The material of the part which contacts is formed with the material of alkali resistance.

  If the material of at least the portion of the recording head in contact with the liquid droplets of the recording head is formed of an alkali-resistant material as in claim 16, the alkaline organic pigment solution is used as it is, such as a quinacridone pigment. Can be used and convenient.

  In order to achieve the above-mentioned object, the invention of claim 17 is characterized in that a solution of an organic pigment dissolved in an alkaline or acidic aqueous medium is circulated as a laminar flow in a flow path on a recording medium, A recording head for ejecting droplets containing organic pigment fine particles produced by the step of changing the hydrogen ion index (pH) of the ink, droplet ejection control means for controlling the ejection timing of the recording head, and the recording medium And a transport unit that moves the recording head relative to the recording medium. A droplet ejection control method using an image forming apparatus, wherein the first dots are formed on the recording medium by the first liquid droplets. A first dot forming step, and a second dot ejection for ejecting a second liquid droplet that forms a second dot that overlaps the first dot after the first liquid droplet has been ejected Step and depositing the second droplet A droplet ejection condition calculating step for obtaining a diameter of the first droplet so that the first droplet and the second droplet do not overlap each other on the surface of the recording medium, A droplet diameter change time calculating step for obtaining a time from when a droplet diameter reaches the recording medium to a value that does not overlap the second droplet on the surface of the recording medium; It is characterized by including.

  Software (program) for realizing the above steps can be configured, and the program can be executed using a control means such as a CPU (central processing unit). Furthermore, the program can be stored in a recording medium.

  According to the present invention, it is possible to eject a pigment ink containing pigment fine particles having a fine particle diameter and excellent monodispersibility from a recording head, and also prevent image disturbance due to overlapping of dots and do not require recording time. Therefore, high-definition images with high saturation can be obtained with pigment ink, and high-speed droplet ejection can be performed.

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

  Of the pigment ink and ink jet recording apparatus that characterize the present invention, the ink jet recording apparatus will be described first.

[Overall configuration of inkjet recording apparatus]
FIG. 1 is an overall configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. As shown in the figure, the inkjet recording apparatus 10 includes a print unit 12 having a plurality of print heads 12K, 12C, 12M, and 12Y provided for each ink color, and each print head 12K, 12C, 12M, An ink storage / loading unit 14 for storing ink to be supplied to 12Y, a paper feeding unit 18 for supplying recording paper 16, a decurling unit 20 for removing curling of the recording paper 16, and a nozzle of the printing unit 12 A suction belt transport unit 22 that is disposed to face a surface (ink ejection surface) and transports the recording paper 16 while maintaining the flatness of the recording paper 16, and a print detection unit 24 that reads a printing result by the printing unit 12, A paper discharge unit 26 that discharges printed recording paper (printed matter) to the outside.

  In FIG. 1, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  In the case of an apparatus configuration that uses roll paper, a cutter (first cutter) 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is disposed on the printing surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  After the decurling process, the cut recording paper 16 is sent to the suction belt conveyance unit 22. The suction belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least portions facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 are horizontal ( Flat surface).

  The belt 33 has a width that is greater than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 1, a suction chamber 34 is provided at a position facing the nozzle surface of the print unit 12 and the sensor surface of the print detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. Then, the suction chamber 34 is sucked by the fan 35 to be a negative pressure, whereby the recording paper 16 on the belt 33 is sucked and held.

  When the power of a motor (not shown in FIG. 1, described as reference numeral 88 in FIG. 6) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, the belt 33 rotates in the clockwise direction in FIG. , And the recording paper 16 held on the belt 33 is conveyed from left to right in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blow method of blowing clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Although a mode using a roller / nip conveyance mechanism instead of the suction belt conveyance unit 22 is also conceivable, if the roller / nip conveyance is performed in the print area, the image easily spreads because the roller contacts the printing surface of the sheet immediately after printing. There is a problem. Therefore, as in this example, suction belt conveyance that does not bring the image surface into contact with each other in the print region is preferable.

  A heating fan 40 is provided on the upstream side of the printing unit 12 on the paper conveyance path formed by the suction belt conveyance unit 22. The heating fan 40 heats the recording paper 16 by blowing heated air onto the recording paper 16 before printing. Heating the recording paper 16 immediately before printing makes it easier for the ink to dry after landing.

  The printing unit 12 is a so-called full line type head in which line type heads having a length corresponding to the maximum paper width are arranged in a direction (main scanning direction) orthogonal to the paper feed direction (see FIG. 2). Although a detailed structural example will be described later, each of the print heads 12K, 12C, 12M, and 12Y has a length that exceeds at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10, as shown in FIG. A line type head in which a plurality of ink discharge ports (nozzles) are arranged is formed.

  A print head 12K corresponding to each color ink in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side along the feeding direction of the recording paper 16 (hereinafter referred to as the paper transport direction). , 12C, 12M, 12Y are arranged. A color image can be formed on the recording paper 16 by discharging the color inks from the print heads 12K, 12C, 12M, and 12Y while the recording paper 16 is conveyed.

  As described above, according to the printing unit 12 in which the full line head that covers the entire width of the paper is provided for each ink color, the operation of relatively moving the recording paper 16 and the printing unit 12 in the sub-scanning direction is performed once. An image can be recorded on the entire surface of the recording paper 16 only by performing it (that is, by one sub-scan). Thereby, it is possible to perform high-speed printing as compared with a shuttle type head in which the print head reciprocates in the main scanning direction, and productivity can be improved.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a print head that discharges light ink such as light cyan and light magenta.

  As shown in FIG. 1, the ink storage / loading unit 14 has tanks that store inks of colors corresponding to the print heads 12K, 12C, 12M, and 12Y, and each tank is connected via a conduit (not shown). The print heads 12K, 12C, 12M, and 12Y communicate with each other. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. ing.

  The print detection unit 24 includes an image sensor for imaging the droplet ejection result of the print unit 12, and functions as a means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor.

  The print detection unit 24 of this example is composed of a line sensor having a light receiving element array that is wider than at least the ink ejection width (image recording width) by the print heads 12K, 12C, 12M, and 12Y. The line sensor includes an R sensor row in which photoelectric conversion elements (pixels) provided with red (R) color filters are arranged in a line, a G sensor row provided with green (G) color filters, The color separation line CCD sensor is composed of a B sensor array provided with a blue (B) color filter. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 24 reads the test pattern printed by the print heads 12K, 12C, 12M, and 12Y for each color, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like. In addition, the print detection unit 24 includes a light source that irradiates light onto the ejected dots.

  A post-drying unit 42 is provided following the print detection unit 24. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined surface uneven shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 26. When the main image (printed target image) and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by the cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 48 is the same as that of the first cutter 28 described above, and includes a fixed blade 48A and a round blade 48B.

  Although not shown in FIG. 1, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

  Next, the structure of the print head 50 will be described. Since the structures of the print heads 12K, 12C, 12M, and 12Y provided for the respective ink colors are common, the print heads are represented by reference numeral 50 in the following.

  FIG. 3 (a) is a plan perspective view showing an example of the structure of the print head 50, and FIG. 3 (b) is an enlarged view of a part thereof. 3C is a perspective plan view showing another example of the structure of the print head 50, and FIG. 4 is a sectional view showing the three-dimensional configuration of the ink chamber unit (along line 4-4 in FIG. 3B). FIG.

  The print head 50 of this example includes a print head 50A and a print head 50B. The print head 50A and the print head 50B are configured to be relatively movable along the recording paper conveyance direction, and the interval between the print heads (recording). The nozzle pitch in the paper transport direction can be varied.

  For example, the print head 50A includes a motor, a transport mechanism such as a ball screw and a slide rail, and a head moving mechanism (not shown) including a guide member, and moves the print head 50A relative to the fixed second print head. There is a mode in which both the print head 50A and the print head 50B are provided with the head moving mechanism described above, and each is configured to be movable. Of course, the print head 50A may be fixed and the print head 50B may be moved.

  Further, as shown in FIG. 3A, the print head 50A and the print head 50B have a plurality of nozzles arranged in a line along a direction substantially perpendicular to the recording paper transport direction. The interval (nozzle pitch) between the nozzles 51A provided in the print head 50A and the nozzle pitch of the nozzles 51B provided in the print head 50B are the same.

  Further, the print head 50A and the second print head are substantially orthogonal to the recording paper conveyance direction so that the nozzle 51B in the second print head is positioned at a substantially intermediate position between the adjacent nozzles 51A in the print head 50A. The position of the direction is determined.

  In other words, the nozzles 51A in the first print head and the nozzles 51B in the print head 50B are arranged in a staggered manner shifted by 1/2 pitch, and each print head is in a direction substantially orthogonal to the recording paper transport direction. This is equivalent to one arranged in a straight line at 1/2 the nozzle pitch within 50.

  In this example, the print head 50A and the print head 50B have been illustrated with a single nozzle row. However, the nozzles may be two-dimensionally arranged in a matrix.

  Here, for convenience, the recording paper conveyance direction is sometimes referred to as a sub-scanning direction, and the direction substantially orthogonal to the recording paper conveyance direction is sometimes referred to as a main scanning direction.

Further, as shown in FIG. 3 (c), short two-dimensionally arranged heads 50 'may be arranged in a staggered manner and connected to form a length corresponding to the entire width of the print medium.

  The pressure chamber 52 provided corresponding to each nozzle 51 has a substantially square planar shape, and the nozzle 51 and the supply port 54 are provided at both corners on the diagonal line. Each pressure chamber 52 communicates with a common flow channel 55 through a supply port 54.

  An actuator 58 having an individual electrode 57 is joined to the pressure plate 56 constituting the top surface of the pressure chamber 52, and the actuator 58 is deformed by applying a driving voltage to the individual electrode 57, and the nozzle 51 Ink is ejected. When ink is ejected, new ink is supplied from the common channel 55 to the pressure chamber 52 through the supply port 54.

  When the nozzles are driven by a full line head having a nozzle row corresponding to the entire width of the paper (recording paper 16), (1) all the nozzles are driven simultaneously, (2) the nozzles are sequentially moved from one side to the other. (3) The nozzles are divided into blocks, and each block is sequentially driven from one side to the other. One row of dots is formed in the paper width direction (direction perpendicular to the paper conveyance direction). Nozzle driving that prints a line or a line composed of a plurality of rows of dots is defined as main scanning.

  When driving the nozzles 51 arranged in a matrix as shown in FIG. 3A, the main scanning as described in the above (3) is preferable. That is, one line is printed in the width direction of the recording paper 16 by driving the nozzle 51A and the nozzle 51B at different timings according to the conveyance speed of the recording paper 16 like the nozzles 51A, 51B, 51A,.

  On the other hand, the sub-scan is defined as the above-described full-line head and the paper are moved relative to each other to repeatedly print a line composed of one row of dots or a line composed of a plurality of rows of dots formed by the above-described main scan. To do.

  In the implementation of the present invention, the nozzle arrangement structure is not limited to the illustrated example. In the present embodiment, a method of ejecting ink droplets by deformation of an actuator 58 typified by a piezo element (piezoelectric element) is employed. In implementing the present invention, an actuator other than the piezoelectric element can be applied to the actuator 58.

FIG. 5 is a schematic diagram showing the configuration of the ink supply system in the inkjet recording apparatus 10.

  The ink supply tank 60 is a base tank for supplying ink, and is installed in the ink storage / loading unit 14 described with reference to FIG. There are two types of ink supply tank 60: a system that replenishes ink from a replenishment port (not shown) and a cartridge system that replaces the entire tank when the remaining amount of ink is low. A cartridge system is suitable for changing the ink type according to the intended use. In this case, it is preferable that the ink type information is identified by a barcode or the like, and ejection control is performed according to the ink type. The ink supply tank 60 of FIG. 5 is equivalent to the ink storage / loading unit 14 of FIG. 1 described above.

  As shown in FIG. 5, a filter 62 is provided between the ink supply tank 60 and the print head 50 in order to remove foreign substances and bubbles. The filter mesh size is preferably equal to or smaller than the nozzle diameter (generally about 20 μm).

  Although not shown in FIG. 5, a configuration in which a sub tank is provided in the vicinity of the print head 50 or integrally with the print head 50 is also preferable. The sub-tank has a function of improving a damper effect and refill that prevents fluctuations in the internal pressure of the head.

  Further, the inkjet recording apparatus 10 is provided with a cap 64 as a means for preventing the nozzle 51 from drying or preventing an increase in ink viscosity near the nozzle 51 and a cleaning blade 66 as a means for cleaning the surface of the nozzle 51. Yes.

  The maintenance unit including the cap 64 and the cleaning blade 66 can be moved relative to the print head 50 by a moving mechanism (not shown), and is moved from a predetermined retracted position to a maintenance position below the print head 50 as necessary. The

  The cap 64 is displaced up and down relatively with respect to the print head 50 by an elevator mechanism (not shown). The cap 64 is raised to a predetermined raised position when the power is turned off or during printing standby, and is brought into close contact with the print head 50, thereby covering the nozzle 51 surface (ink ejection surface) with the cap 64.

  During printing or standby, if the frequency of use of a specific nozzle 51 is reduced and ink is not ejected for a certain period of time, the ink solvent near the nozzle evaporates and the ink viscosity increases. In such a state, ink cannot be ejected from the nozzle 51 even if the actuator 58 operates.

  Before such a state is reached (within the range of the viscosity that can be discharged by the operation of the actuator 58), the actuator 58 is operated, and the cap 64 (ink near the nozzle whose viscosity has increased) is discharged. Preliminary ejection (purging, idle ejection, brim ejection) is performed toward the ink receiver.

  Further, when air bubbles are mixed into the ink in the print head 50 (in the pressure chamber 52), the ink cannot be ejected from the nozzle even if the actuator 58 is operated. In such a case, the cap 64 is applied to the print head 50, the ink in the pressure chamber 52 (ink mixed with bubbles) is removed by suction with the suction pump 67, and the suctioned and removed ink is sent to the collection tank 68. .

In this suction operation, the deteriorated ink with increased viscosity (solidified) is sucked out when the ink is initially loaded into the head or when the ink is used after being stopped for a long time. Since the suction operation is performed on the entire ink in the pressure chamber 52, the amount of ink consumption increases. Therefore, it is preferable to perform preliminary ejection when the increase in ink viscosity is small.

  The cleaning blade 66 is made of an elastic member such as rubber, and can slide on the ink discharge surface (surface of the nozzle plate) of the print head 50 by a blade moving mechanism (wiper) (not shown). When ink droplets or foreign substances adhere to the nozzle plate, the nozzle plate surface is wiped by sliding the cleaning blade 66 on the nozzle plate to clean the nozzle plate surface. It should be noted that when the ink ejection surface is cleaned by the blade mechanism, preliminary ejection is performed in order to prevent foreign matter from being mixed into the nozzle 51 by the blade.

  FIG. 6 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10. The inkjet recording apparatus 10 includes a communication interface 70, a system controller 72, an image memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 86. As the communication interface 70, a serial interface such as USB, IEEE 1394, Ethernet, and wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted. Image data sent from the host computer 86 is taken into the inkjet recording apparatus 10 via the communication interface 70 and temporarily stored in the image memory 74. The image memory 74 is a storage unit that temporarily stores an image input via the communication interface 70, and data is read and written through the system controller 72. The image memory 74 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 72 is a control unit that controls each unit such as the communication interface 70, the image memory 74, the motor driver 76, and the heater driver 78. The system controller 72 includes a central processing unit (CPU) and its peripheral circuits, and performs communication control with the host computer 86, read / write control of the image memory 74, and the like, as well as a transport system motor 88 and heater 89. A control signal for controlling is generated.

  The motor driver 76 is a driver (drive circuit) that drives the motor 88 in accordance with an instruction from the system controller 72. The heater driver 78 is a driver that drives the heater 89 such as the post-drying unit 42 in accordance with an instruction from the system controller 72.

  The print control unit 80 has a signal processing function for performing various processing and correction processing for generating a print control signal from the image data in the image memory 74 according to the control of the system controller 72, and the generated print A control unit that supplies a control signal (print data) to the head driver 84. Necessary signal processing is performed in the print controller 80, and the ejection amount and ejection timing of the ink droplets of the print head 50 are controlled via the head driver 84 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 80 includes an image buffer memory 82, and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print control unit 80. In FIG. 6, the image buffer memory 82 is shown in a form associated with the print control unit 80, but it can also be used as the image memory 74. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with a single processor.

  The head driver 84 drives the actuators of the print heads 12K, 12C, 12M, and 12Y for each color based on the print data given from the print control unit 80. The head driver 84 may include a feedback control system for keeping the head driving conditions constant.

  Needless to say, each member is made of a material that is resistant to alkaline ink. Examples of the resin material most suitable for the ink supply tank 60 and the print head 50 include polystyrene, polyethylene, polypropylene, and ABS resin. In addition, it is preferable that the liquid contact portion such as the pressure chamber 52 is processed by Teflon (registered trademark) or the metal material is SUS304, SUS316, or SUS316L. Suitable rubber materials for the ink supply system rubber tube include vinyl methyl silicone rubber, fluorinated silicone rubber, and ethylene propylene rubber.

(Control of droplet ejection timing)
The droplet ejection timing control (droplet ejection control) of the inkjet recording apparatus 10 will be described with reference to FIGS. In the ink jet recording apparatus 10, when dots formed on the recording paper 16 overlap, the ink droplet 110 (the ink droplet 100 (the ink droplet 100 previously ejected) is ejected next before the penetration of the recording paper 16 is finished). The droplet ejection (recording) timing is controlled so as to perform the droplet ejection shown in FIG.

  FIG. 7 shows the ink droplet 100 previously ejected. The droplet diameter of the ink droplet 100 on the surface of the recording paper 16 is D1a.

  When ink is ejected onto the penetrating recording paper 16 (recording medium), the ink droplet 100 that has landed on the surface of the recording paper 16 penetrates into an image receiving layer (not shown) of the recording paper 16 as time passes. Since the penetration is completed from the outside to the inside of the ink droplet 100, the diameter of the ink droplet gradually decreases toward the center.

  When the predetermined time T elapses, the solvent on the surface of the recording paper 16 runs out, and the ink droplet 100 completely penetrates into the recording paper 16. Here, dots having a predetermined size (in this embodiment, the same diameter as the diameter of the ink droplet upon landing) are formed. This time T is defined as a complete penetration time.

  FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7, and shows a state immediately after the ink droplet 100 has landed on the recording paper 16. FIG.

  FIG. 9 shows a state in which, after the ink droplet 100 has landed on the recording paper 16, a predetermined time less than the complete penetration time T has elapsed, and the diameter of the ink droplet 100 on the surface of the recording paper 16 becomes D1b. .

  A circle indicated by a broken line in FIG. 9 indicates the dot 102 formed by the ink droplet 100, and the size thereof is substantially the same as the size of the ink droplet when the ink droplet 100 lands on the recording paper 16. In other words, the ink droplet 100 forms a dot 102 having a diameter D1a.

  FIG. 9 shows a state in which an ink droplet 110 having a diameter D2a is ejected to form a dot 112 having a dot diameter D2a at an interval (dot pitch interval) Pt from the dot 102.

  The diameter D1b after the passage of time δT after the previously ejected ink droplet 100 landed on the recording paper 16, the diameter D2a of the ink droplet 110 when landed on the recording paper 16, the ink droplet 100 and the ink When the relationship between the distance from the droplet 110 (corresponding to the pitch of the dots formed by the ink droplet 100 and the ink droplet 110) Pt satisfies the following equation [Equation 1], the ink droplet 100 and the ink on the surface of the recording paper 16 Since the ink droplets are not mixed with the droplets 110, the shapes of the ink droplets 100 and the dots 102 and the dots 112 (formed in the same position and in the same size as the ink droplets 110 in FIG. 9) do not collapse. Therefore, a desired dot shape can be obtained.

[Equation 1]
D1b <2 × Pt -D2a
Here, the condition in which the dot 102 and the dot 112 overlap is represented by Pt <(D1a / 2) + (D2a / 2). In other words, the condition where the dot 102 and the dot 112 overlap is when the sum of the radius of the dot 102 and the radius of the dot 112 is larger than the dot pitch Pt.

  The dots 102 shown in FIG. 9 are recorded after the ink droplet 100 has not penetrated into the recording paper 16 (the region indicated as the ink droplet 100) and the ink droplet 100 has penetrated into the recording paper 16. There is a region in which the ink coloring matter (solute) is held inside the image receiving layer of the paper 16 (a region obtained by excluding the region shown as the ink droplet 100 from the region of the dot 102 shown by the broken line). Of the two regions, the other ink droplets 110 can be landed on the region where the ink droplet 100 has penetrated into the recording paper 16.

  FIG. 10 is a cross-sectional view (corresponding to FIG. 8) showing a cross section of the ink droplet 100 and the ink droplet 110. When the ink droplet 110 permeates the recording paper 16, even if the ink droplet 100 and the ink droplet 110 are mixed in the image receiving layer of the recording paper 16 at the portion where the dot 102 and the ink droplet 110 overlap, the ink droplet Since 100 has already penetrated into the image receiving layer and the ink coloring matter (solute) is retained in the image receiving layer, the shape of the dot 102 inside the image receiving layer hardly changes.

  When the above-described complete penetration time T elapses after the ink droplet 110 has landed on the recording paper 16, the penetration of the ink droplet 110 into the recording paper 16 is finished, and as shown in FIG. D2a dots 112 are formed.

  12 is a cross-sectional view showing a cross section of the dot 102 and the dot 112 shown in FIG.

  Therefore, when two dots overlap, the next ink can be ejected without waiting for the complete permeation time T for the permeation of the previously ejected ink droplet to finish (in the state of D1b> 0). .

  That is, the diameter P1 of the ink droplet 100 that satisfies [Equation 1] at the time of landing of the ink droplet 110 from the interval Pt between the ink droplet 100 that landed first and the ink droplet 110 that landed next, the diameter D2a when the ink droplet 110 landed. D1b is obtained, and the permeation time δT is obtained from the obtained diameter D1b of the ink droplet 100 and the diameter D1a when the ink droplet 100 is landed. The droplet ejection timing of the ink droplet 100 and the ink droplet 110 is controlled with the penetration time δT thus determined as the droplet ejection interval.

  In the case of an ink that has a large molecular structure of the ink dye and is mixed in the solvent without dissolving in the solvent, when the ink droplets land on the surface of the recording paper 16, the solvent penetrates into the image receiving layer, and the dye is partially inside the image receiving layer. Many pigments solidify on the surface of the paper, though some penetrate into the surface.

  At that time, the portion of the ink on the recording paper 16 that has landed as droplets becomes smaller from the outside toward the inside as the solidification (curing) progresses. Therefore, the present invention can be applied to prevent mixing of ink droplets on the surface of the recording paper 16.

  FIG. 13 is a block diagram illustrating details of the droplet ejection control unit 200 that executes the droplet ejection control described above. The droplet ejection control unit 200 is included in the system (print control unit 80) shown in FIG.

  When the image data 202 is acquired from the host computer 86 shown in FIG. 6, the dot data generation unit 210 performs conversion from RGB data to CMY data, distribution of dark and light inks, and generation of CMYK dot data.

  Next, in the inequality calculation unit 212, the pitch Pt of two dots (for example, the ink droplet 100 and the ink droplet 110 shown in FIG. 11) and the diameter D2a of the ink droplet (ink droplet 110 of FIG. 11) to be ejected later. From this, D1b is obtained as the diameter of the previously ejected ink droplet (ink droplet 100 in FIG. 11).

  On the other hand, the information regarding the time change of the ink droplet size to be used stored in the dot diameter calculation / storage unit 214 is referred to, and the timing calculation unit 216 determines when the ink droplet that forms the previously ejected dot is landed. The permeation time δT (droplet ejection interval) from the droplet diameter D1a to the aforementioned D1b is obtained. Further, timing control parameters in the sub-scanning direction (recording paper conveyance speed, etc.) and timing control parameters in the main scanning direction (interval L between the print head 50A and the print head 50B, etc.) are determined from the penetration time δT.

  Note that in a mixed pattern in which dots having different dot diameters exist, the representative value calculation unit 217 uses a representative value of the penetration time δT in the mixed pattern, timing control parameters in the sub-scanning direction (recording paper conveyance speed, etc.), A representative value of a timing control parameter (such as an interval L between the print head 50A and the print head 50B) in the scanning direction is obtained.

  For this representative value, the penetration time δT, the control parameter in the main scanning direction, the maximum value of the control parameter in the sub-scanning direction may be applied, or the minimum value, the average value, the most frequently used value, etc. can be applied as appropriate. It is.

  Based on the penetration time δT thus obtained, the timing control parameter in the sub-scanning direction, and the timing control parameter in the main scanning direction, the nozzle driving signal generation unit 218 generates a driving signal 220 for each nozzle.

  Here, the speed at which the ink droplet permeates the recording paper 16 mainly depends on the type of ink, the type of the recording paper 16, the environmental temperature, the humidity, and the like.

  The dot diameter calculation / storage unit 214 stores these pieces of information in a data table and provides the timing calculation unit 216 with parameters for determining the permeation time δT calculated by the calculation.

  The penetration time δT may be obtained by referring to the data of the diameter D1b from a database in which the diameter D1b is calculated and registered in advance from the diameter D1a, the diameter D2a, and the dot interval Pt. The database may be provided inside the inkjet recording apparatus 10 or may be provided outside.

  For example, the ink type information 230 may be read when the ink cartridge is loaded, the ink type information 230 may be stored, and the ink information may be provided to the timing calculation unit 216 when printing is performed. Similarly, the paper type information 232 can be read and stored when the recording paper 16 is loaded.

  The ink type information 230 and the paper type information may be automatically read at the time of loading from a wireless tag or a barcode attached to an ink cartridge or a paper tray, or may be input by an operator via a keyboard or a touch panel.

  A change in ink droplet diameter over time for each ink type and paper type will be described with reference to FIGS.

  FIG. 14 is a graph 300 showing a change in ink droplet diameter over time when ink A1 and paper B1 are used. In the graph 300, a curve 302 indicates a case where the diameter of the ink droplet upon landing is 100 μm, and a curve 304 and a curve 306 indicate the case where the diameter of the ink droplet upon landing is 60 μm and 30 μm, respectively.

  For example, in curve 302, it can be seen that the time from the ink droplet diameter of 100 μm at the time of landing to 40 μm is approximately 3.9 msec. On the other hand, in the curve 304, the time from the ink droplet diameter of 60 μm to 0 μm (that is, the end of permeation) at the time of landing is 7.0 msec, and the change amount of the ink droplet diameter is the same as that described with reference to the curve 302. Although it is 60 μm, the time required for this varies depending on the diameter of the ink droplet upon landing.

  Therefore, in the graph 300, it is preferable to provide a curve for each ink droplet diameter at the time of landing, in addition to the curve 302, the curve 304, and the curve 306.

  FIG. 15 is a graph 320 showing changes in ink droplet diameter over time when the ink droplet diameter upon landing is 100 μm for three types of ink and paper. In the graph 320, a curve 321 indicates a combination of the ink A1 and the sheet B1, a curve 322 indicates a combination of the ink A2 and the sheet B2, and a curve 323 indicates a combination of the ink A3 and the sheet B3.

  As described above, when a penetrating recording paper 16 is used for the combination of a plurality of ink types and a plurality of recording paper materials, the landed ink droplets may penetrate into the image receiving layer in the recording paper 16 or may not. When the penetrating recording paper 16 is used, the time required for ink droplet size change accompanying the solidification (curing) on the surface of the recording paper 16 (that is, the penetrating time, the solidifying time, and the curing time δT) is determined in advance through experiments or simulations. It is obtained and stored in the dot diameter calculation / storage unit 214.

  The storage form may be a graph (an arithmetic expression such as an approximate expression for each curve), but a mode in which each curve is stored in a data table is preferable.

  In addition to the ink type and the paper type, there may be representative values under some conditions depending on the environmental temperature, humidity, and the like, and it may be estimated by complementation that corresponds to the actual environmental conditions.

  Furthermore, when ink or paper of a type that is not stored is set, a change in the ink droplet that has actually landed may be imaged by an imaging means or the like and measured, and the penetration time δT may be obtained each time. A line sensor, an area sensor, or the like may be used as the image pickup means, and the image detecting unit can also be used as the print detection unit 24 shown in FIG.

  In this example, as shown in FIG. 16, the dot pitch Pts in the recording paper conveyance direction (sub-scanning direction) and the dot pitch Ptm in the direction substantially orthogonal to the recording paper conveyance direction (main scanning direction) are divided as necessary. It can be handled separately. As a result, the droplet ejection timing δT obtained from D1b obtained by applying [Equation 1] can also handle the droplet ejection interval δTm in the main scanning direction and the droplet ejection interval δTs in the sub-scanning direction. .

  Further, for example, the present invention can also be applied to the droplet ejection timing of dots adjacent in an oblique direction that is not adjacent in the main scanning direction and the sub-scanning direction like the dot 250 and the dot 256 in FIG.

  As shown in FIG. 3A, the ink jet recording apparatus 10 includes a print head 50A and a print head 50B arranged in the sub-scanning direction, and the interval L between the print head 50A and the print head 50B is variable. Is possible. Therefore, by adjusting the interval L between the print head 50A and the print head 50B and the conveyance speed of the recording paper 16, it is possible to control the droplet ejection interval δTm of dots adjacent in the main scanning direction in the line head.

  That is, when the dot 252 adjacent to the dot 250 ejected from the print head 50A is ejected from the print head 50B, the main scanning is performed from the conveyance speed Vs of the recording paper 16 and the distance L between the print head 50A and the print head 50B. The droplet ejection interval δTm in the direction is obtained by the following equation [Equation 2].

[Equation 2]
δTm = L / Vs
On the other hand, the droplet ejection interval δTs in the sub-scanning direction is obtained from the recording paper transport speed Vs and the droplet ejection interval Pts in the sub-scanning direction according to the following equation [Equation 3].

[Equation 3]
δTs = Pts / Vs
In this example, the full-line type line head has been described, but the present invention is also applicable to a serial head (shuttle scan type head). The serial head has two nozzle rows in the sub-scanning direction (distance between column centers: Ls), and one nozzle row and the other nozzle row are arranged in a staggered manner with a half pitch shift. Has been. Furthermore, the interval between the nozzle rows can be varied.

  The droplet ejection interval δTm in the main scanning direction is obtained from the following equation (4) from the main scanning direction speed (scanning speed) Vm of the print head and the dot pitch Ptm in the main scanning direction.

[Equation 4]
δTm = Ptm / Vm
In order to satisfy the above [Equation 4], a dot 252 is ejected onto the dot 250, and similarly a dot 256 is ejected onto the dot 254.

  Similarly, the droplet ejection interval δTs in the sub-scanning direction is obtained by the following equation [Equation 5] from the recording paper transport speed Vs and the interval Ls in the sub-scanning direction of the nozzle row.

[Equation 5]
δTs = Ls / Vs
In order to satisfy the above [Equation 5], a dot 254 is ejected onto the dot 250, and similarly a dot 256 is ejected onto the dot 252.

  The present invention is also applicable to the case where mixed patterns having different dot pitches and dot diameters are formed in one image. In the mixed pattern, the droplet ejection interval δTm in the main scanning direction and the droplet ejection interval δTs in the sub-scanning direction are obtained for all combinations of dot pitch and dot diameter, and the maximum values of the obtained droplet ejection intervals δTm and δTs are obtained. If δTmax-m and δTmax-s are the representative droplet ejection interval values, the control operation can be simplified.

  That is, the droplet ejection interval of the image is set according to the pattern having the longest droplet ejection interval in the image. Based on the ink droplet ejection timing of the overlapping portion with the most severe bleeding condition, the other regions are also unified at the droplet ejection timing.

  Further, in consideration of safety, the droplet ejection interval of the image may be larger than the maximum values δTmax-m and δTmax-s.

  FIG. 17 is a flowchart showing the flow of the droplet ejection timing control described above.

  When image data is input and printing control is started (step S10), the inter-dot pitch Pt between the first dot (for example, dot 102 in FIG. 11) and the second dot (for example, dot 112 in FIG. 11) The diameter D1b of the ink droplet 100 forming the first dot 102 is calculated from the diameter D2a of the second dot and using the above-described [Equation 1] (step S12 in FIG. 17).

  Next, the first dot is formed according to the ink type and the paper type (refer to the data table, graph 300, and graph 320 stored in the dot diameter calculation / storage unit 214 shown in FIG. 13). The penetration time δT, which is the difference between the landing time of the first dot and the second dot, is determined from the diameter D1a at the time of landing of the ink droplet (the ink droplet landed first) and D1b obtained in step S12. (Step S14).

  Subsequent to step S14, timing control in the sub-scanning direction is executed. When the permeation time δT is obtained, the sub-scanning direction speed (recording paper conveyance speed) Vs is obtained by the above-described [Equation 3] in the timing calculation unit 216 shown in FIG. 13 (step S16).

  Subsequently, timing control in the main scanning direction is executed. From [Equation 2] described above, the distance L between the print head 50A and the print head 50B shown in FIG. 16 is obtained and adjusted to this (step S18).

  As described above, timing control in the sub-scanning direction and main scanning direction is performed, and when one image is formed, the printing control is finished (step S20).

  Note that the interval L between the print head 50A and the print head 50B may be set slightly larger with a margin, and the recording paper conveyance speed may be set and changed according to the ink type and the paper type.

  The scope of application of the present invention is that the amount of dots formed by ink droplets landed later (dot 112 in FIG. 11) overlaps the center of the dot formed by previously landed ink droplets (dot 102 in FIG. 11). This is a small range, which satisfies the following equation [Formula 6].

[Equation 6]
D2a / 2 <Pt
It is possible to configure a program (software) that realizes the droplet ejection control described above and install the program in the inkjet recording apparatus 10. The program can also be recorded on a recording medium (magnetic recording medium, optical recording medium, etc.), distributed, or installed on a device using the recording medium.

  In the inkjet recording apparatus 10 configured as described above, when overlapping dots are formed, the ink droplets ejected earlier and later are determined from the inter-dot pitch Pt and the diameter D2a of the droplets ejected later. The diameter D1b of the previously ejected ink droplet is determined so that the ejected ink droplet does not mix on the surface of the recording paper 16.

  Further, a permeation time δT until the diameter of the previously ejected ink droplet reaches the landing diameter D1a to D1b is obtained, and this permeation time δT is determined as the ink droplet ejected earlier and the ink droplet ejected later. The droplet ejection control with the droplet ejection interval is performed.

  The next droplet can be ejected without waiting for the complete permeation time T for the permeation of the previously ejected ink droplets to the recording paper 16, and the printing time can be shortened. In addition, on the surface of the recording paper 16, the ink droplet previously ejected and the ink droplet ejected next are not mixed, and the ink droplet previously ejected also in the image receiving layer of the recording paper 16. The ink droplets ejected next time are not mixed with each other, so that a desired dot shape can be obtained without breaking the dot diameter.

  Since the droplet ejection interval depends on environmental conditions such as ink type, paper type, temperature, and humidity, it is calculated according to these conditions. Further, the droplet ejection interval can be obtained for each of the main scanning direction and the sub-scanning direction, and can be controlled for each of the main scanning direction and the sub-scanning direction. Therefore, a line head or a serial head can be applied to the print head.

  In mixed patterns with different dot diameters and inter-dot pitches, the droplet ejection interval is obtained for each pattern, and the maximum droplet ejection interval may be used as the droplet ejection interval of the image. An added value may be used.

  In the above embodiment, an inkjet recording apparatus has been described as an example of an image recording apparatus, but the scope of application of the present invention is not limited to this. The present invention can also be applied to liquid discharge apparatuses such as dispensers and coating apparatuses that discharge liquids such as water, chemicals, and processing liquids onto a medium to be discharged.

  Next, the pigment ink will be described.

[Manufacture of organic pigment fine particles and dispersion containing the same]
The apparatus for producing an organic pigment used in the present invention has a flow path capable of forming a laminar flow, preferably an apparatus having a flow path (channel) having an equivalent diameter of 10 mm or less, more preferably an equivalent diameter. It is an apparatus having a flow path of 1 mm or less. First, the equivalent diameter will be described below.

Equivalent diameter, also called equivalent diameter, is a term used in the field of mechanical engineering. When an equivalent circular pipe is assumed for a pipe having an arbitrary cross-sectional shape (a flow path in the present invention), the diameter of the equivalent circular pipe is referred to as an equivalent diameter. The equivalent diameter (deq) is defined as deq = 4 A / p, using A: cross-sectional area of the pipe and p: wet wetting length (circumferential length) of the pipe. When applied to a circular tube, this equivalent diameter corresponds to the circular tube diameter. The equivalent diameter is used to estimate the flow or heat transfer characteristics of the pipe based on the data of the equivalent circular pipe, and represents the spatial scale (typical length) of the phenomenon. The equivalent diameter is deq = 4a ² / 4a = a for a regular square tube with one side a, and for a regular triangle tube with one side a,

   In the flow between parallel flat plates having a flow path height h, deq = 2h (for example, see “Mechanical Engineering Encyclopedia” edited by the Japan Society of Mechanical Engineers, 1997, Maruzen Co., Ltd.).

  When water is poured into the tube, a thin tube is inserted into its central axis and colored liquid is injected, the colored liquid flows as a single line while the flow rate of water is low, and the water flows on the tube wall. It flows straight in parallel. However, when the flow velocity is increased and reaches a certain flow velocity, the water flow suddenly becomes turbulent, and the colored liquid is mixed with the water flow to become a colored flow. The former flow is called laminar flow, and the latter flow is called turbulent flow.

  Whether the flow becomes laminar or turbulent depends on whether the Reynolds number, which is a dimensionless number indicating the flow, is below a certain critical value. The smaller the Reynolds number, the easier it is to form a laminar flow. The Reynolds number Re of the flow in the pipe is expressed by the following equation.

Re = D <υx> ρ / μ
D is the equivalent diameter of the tube, <υx> is the cross-sectional average velocity, ρ is the density of the fluid, and μ is the viscosity of the fluid.
As can be seen from this equation, the smaller the equivalent diameter, the smaller the Reynolds number. Therefore, in the case of an equivalent diameter of μm, it becomes easy to form a stable laminar flow. It can also be seen that the liquid physical properties of density and viscosity also affect the Reynolds number, and the smaller the density and the larger the viscosity, the smaller the Reynolds number and the easier it is to form a laminar flow.

  The critical Reynolds number is called the critical Reynolds number. The critical Reynolds number is not always constant, but the next value is the reference.

Re <2300 laminar flow
Re> 3000 Turbulence
3000 ≧ Re ≧ 2300 Transient state As the equivalent diameter of the flow path decreases, the surface area per unit volume (specific surface area) increases, but when the flow path becomes microscale, the specific surface area increases dramatically. The heat transfer efficiency through the wall is very high. Since the heat transfer time (t) in the fluid flowing through the flow path is expressed by t = deq ² / α (α: thermal diffusivity of the liquid), the heat transfer time becomes shorter as the equivalent diameter becomes smaller. That is, when the equivalent diameter is 1/10, the heat transfer time is 1/100. When the equivalent diameter is microscale, the heat transfer speed is extremely fast.

  That is, since the Reynolds number is small in a micro-size space having an equivalent diameter of microscale, the flow reaction can be performed under stable laminar flow control. Since the interfacial surface area between the laminar flows is very large, it is possible to mix the component molecules at high speed and accurately by molecular diffusion between the interfaces while maintaining the laminar flow. In addition, the use of a channel wall having a large surface area enables precise temperature control and precise control of reaction time by flow rate control of the flow reaction. Therefore, among the channels forming the laminar flow of the present invention, a microscale channel having an equivalent diameter which is a field capable of highly controlling reaction is defined as a micro reaction field.

  As shown in the description of the Reynolds number, the formation of a laminar flow is greatly influenced not only by the size of the equivalent diameter but also by the flow conditions including liquid properties such as viscosity and density. Therefore, in the present invention, the equivalent diameter of the flow path is not limited as long as the flow path can be made laminar, but a size capable of easily forming a laminar flow is preferable. Preferably it is 10 mm or less, More preferably, it is 1 mm or less which forms a micro reaction field. More preferably, it is 10 micrometers-1 mm, Most preferably, it is 20-300 micrometers.

  A typical reactor having a particularly preferable microscale size channel (channel) of the present invention is generally referred to as a “microreactor” and has recently been greatly developed (for example, W. Ehrfeld, V. Hessel, H. Loewe, "Microreactor", 1Ed (2000) WILEY-VCH).

  The general microreactor is provided with a plurality of microchannels having an equivalent diameter of several μm to several hundreds of μm when the cross section is converted into a circle, and a mixing space connected to these microchannels. In such a microreactor, a plurality of solutions are introduced into a mixing space through a plurality of microchannels, thereby mixing the plurality of solutions or causing a chemical reaction with the mixing.

  Next, the main points in which the reaction by the microreactor is different from the batch method using a tank or the like will be described. Liquid-phase chemical reactions and two-phase liquid-phase chemical reactions generally occur when molecules meet at the interface of the reaction solution. The area of the interface increases and the reaction efficiency increases significantly. In addition, the diffusion time of the molecule itself is proportional to the square of the distance. This means that as the scale is reduced, the reaction proceeds more easily due to the diffusion of the molecules without active mixing of the reaction solution, and the reaction tends to occur. In microspaces, the Reynolds number (the dimensionless number that characterizes the flow) is small, so the flow is dominated by laminar flow, and the molecules that exist in each solution at the interface where the solutions are in a laminar flow state. Exchange occurs, and the migrated molecules cause precipitation and reaction.

  When a microreactor having such characteristics is used, the reaction time and temperature between solutions can be precisely controlled as compared with a conventional batch system using a large volume tank or the like as a reaction field. In the case of the batch method, the reaction proceeds at the reaction contact surface at the initial stage of mixing, particularly between solutions with a high reaction rate, and the primary product generated by the reaction between the solutions continues to be reacted in the vessel. Therefore, there is a possibility that the product becomes non-uniform or the crystals of the product grow more than necessary and become coarse in the mixing container. On the other hand, according to the microreactor used in the present invention, the solution circulates continuously with almost no stagnation in the mixing container, so that the primary product generated by the reaction between the solutions is in the mixing container. It is possible to suppress the subsequent reaction during the stay, and it is possible to take out pure primary products that were difficult to remove in the past, and also to agglomerate and coarsen crystals in the mixing vessel It becomes difficult to occur.

  In addition, when a small amount of chemical substances produced by an experimental production facility is manufactured (scaled up) in a large amount by a large-scale production facility, a large-scale batch method is conventionally used. It took a lot of labor and time to obtain reproducibility at the manufacturing equipment, but this was achieved by parallelizing (numbering up) the production lines using microrear coolers according to the required production volume. There is a possibility that labor and time for obtaining such reproducibility can be greatly reduced.

  A method for producing a laminar flow channel used in the present invention will be described below. When the flow path is 1 mm or more in size, it can be made relatively easily by using a conventional machining technique. However, when the size is 1 mm or less, particularly when the size is 500 μm or less, the production becomes extremely difficult. A micro-sized channel (micro channel) is often formed on a solid substrate using a microfabrication technique. Any material can be used as the substrate material as long as it is not easily corroded. For example, metal (for example, stainless steel, hastelloy (Ni—Fe alloy), nickel, aluminum, silver, gold, platinum, tantalum, or titanium), glass, plastic, silicone, Teflon (registered trademark), or ceramics.

  Representative examples of microfabrication techniques for producing microchannels include LIGA (Roentgen-Lithographie Galvanik Abforming) technology using X-ray lithography, high aspect ratio photo using EPON SU-8 (trade name). Lithography method, micro electric discharge machining method (μ-EDM (Micro Electro Discharge Machining)), deep RIE (Reactive Ion Etching) silicon high aspect ratio processing method, Hot Emboss processing method, optical modeling method, laser processing method, ion beam Machining methods, and mechanical micro-cutting methods using micro tools made of hard materials such as diamond. These techniques may be used alone or in combination. Preferred microfabrication techniques are LIGA technology using X-ray lithography, high aspect ratio photolithography using EPON SU-8, micro electrical discharge machining (μ-EDM), and mechanical micro-cutting. In recent years, the application of fine injection molding technology to engineering plastics has been studied.

  Joining techniques are often used when creating microchannels. The usual bonding techniques are roughly divided into solid phase bonding and liquid phase bonding, and the commonly used bonding methods are pressure bonding and diffusion bonding as solid phase bonding, welding, eutectic bonding, soldering as liquid phase bonding, Adhesion or the like is a typical joining method. In addition, during assembly, a highly precise bonding method that maintains dimensional accuracy without deteriorating material due to high temperature heating or destruction of micro structures such as flow paths due to large deformation is desirable. There are bonding, anodic bonding, surface activation bonding, direct bonding using hydrogen bonding, bonding using HF aqueous solution, Au-Si eutectic bonding, void-free bonding, and the like.

  The microchannel according to the present invention is not limited to one prepared on a solid substrate using a microfabrication technique, and may be various types of fused silica capillary tubes having an inner diameter of several μm to several hundred μm that can be obtained. Various silicon tubes, fluororesin tubes, stainless steel tubes, PEEK tubes (polyether ether ketone tubes) with an inner diameter of several μm to several hundreds of μm that are commercially available for high-performance liquid chromatographs and gas chromatographs are also used. Is possible.

  So far, microreactors have been reported on devices aimed at improving reaction efficiency. For example, Japanese Patent Application Laid-Open Nos. 2003-210960, 2003-210963, and 2003-210959 relate to micromixers, and the present invention can use these microdevices.

  The microchannel used in the present invention may be surface-treated depending on the purpose. In particular, when an aqueous solution is manipulated, surface treatment is important because adsorption of the sample to glass or silicon may be a problem. It would be desirable to achieve fluid control within a micro-sized channel without incorporating moving parts that require complex fabrication processes. For example, it is possible to create a hydrophilic region and a hydrophobic region by surface treatment in the flow path, and manipulate the fluid by utilizing the difference in surface tension acting on the boundary. As a method for surface treatment of glass or silicon, hydrophobic or hydrophilic surface treatment using a silane coupling agent is frequently used.

  In order to introduce and mix reagents and samples into the flow path, a fluid control function is required. In particular, since the behavior of the fluid in the microchannel has a property different from that of the macroscale, a control method suitable for the microscale must be considered. The fluid control method includes a continuous flow method and a liquid droplet (liquid plug) method in terms of form classification, and an electric drive method and a pressure drive method in terms of drive force classification.

  These methods are described in detail below. The most widely used form for handling fluid is the continuous flow system. In continuous flow type fluid control, the entire microchannel is generally filled with fluid, and the entire fluid is generally driven by a pressure source such as a syringe pump prepared outside. This method has a great advantage that a control system can be realized with a relatively simple setup, although it is difficult to have a large dead volume.

  As a method different from the continuous flow method, there is a droplet (liquid plug) method. In this system, droplets partitioned by air are moved in the reactor or in a flow path leading to the reactor, and each droplet is driven by air pressure. At that time, a vent structure that allows the air between the droplet and the channel wall or between the droplets to escape to the outside as needed, and a valve structure that keeps the pressure in the branched channel independent of other parts Etc. need to be prepared inside the reactor system. Further, in order to control the pressure difference and operate the droplet, it is necessary to construct a pressure control system including a pressure source and a switching valve outside. In this way, the droplet system makes the device configuration and the reactor structure somewhat complicated, but it can be operated in multiple stages, such as operating several droplets individually and sequentially performing several reactions. The degree of freedom of configuration increases.

  As a driving method for fluid control, an electric driving method is used in which an electroosmotic flow is generated by applying a high voltage to both ends of a flow path (channel) and fluid is moved by this, and pressure is applied to the fluid using a pressure source outside. In general, a pressure driving method of moving by applying a pressure is widely used. The difference between the two is that, for example, the behavior of the fluid is a flat distribution when the flow velocity profile is electrically driven in the cross section of the flow path, whereas the center of the flow path is It is known that the wall portion is fast and has a slow distribution, and the electric drive method is more suitable for the purpose of moving the sample plug while maintaining the shape thereof. When the electric drive method is used, the flow path needs to be filled with a fluid, so it must be in the form of a continuous flow method, but the fluid can be manipulated by electrical control. Therefore, for example, a relatively complicated process of creating a temporal concentration gradient by changing the mixing ratio of two kinds of solutions continuously is realized. In the case of the pressure drive system, there is almost no influence on the substrate because control is possible regardless of the electrical properties of the fluid, and secondary effects such as heat generation and electrolysis do not need to be considered. The application range is wide. On the other hand, it is necessary to automate complicated processes such as the necessity of preparing a pressure source outside and the change of the response characteristics of the operation according to the size of the dead volume of the pressure system.

  The method used as the fluid control method in the present invention is appropriately selected according to the purpose, but is preferably a continuous flow type pressure driving method.

  The temperature control in the flow path of the present invention may be controlled by placing the entire apparatus having the flow path in a temperature-controlled container, or a heater structure such as a metal resistance wire or polysilicon is made in the apparatus. However, this may be used for heating and the thermal cycle may be performed by natural cooling for cooling. For temperature sensing, when using a metal resistance wire, it is preferable to create another resistance wire that is the same as the heater, and to detect the temperature based on the change in the resistance value. When using polysilicon, Detection is preferably performed using a thermocouple. Moreover, you may heat and cool from the outside by making a Peltier device contact a flow path. Which method is used is selected in accordance with the application and the material of the flow path body.

  In the present invention, the production of the pigment or the preparation of the pigment dispersion is performed while flowing in the flow path, that is, by a continuous flow method. Therefore, the reaction time is controlled by the time spent in the flow path. The residence time is determined by the length of the flow path and the introduction speed of the reaction solution when the equivalent diameter is constant. Although there is no restriction | limiting in particular in the length of a flow path, Preferably they are 1 mm or more and 10 m or less, More preferably, they are 5 mm or more and 10 m or less, Especially preferably, they are 10 mm or more and 5 m or less.

  The number of flow paths used in the present invention is appropriately provided in the reaction apparatus, and of course, one may be used, but if necessary, several flow paths are arranged in parallel (numbering up), and the processing amount is Can be increased.

  The typical example of the reactor used for this invention was shown to Fig.18 (a) -21. Needless to say, the present invention is not limited to these examples.

  FIG. 18A is an explanatory view of a reactor (1010) having a Y-shaped channel, and FIG. 18B is a cross-sectional view taken along the line II. The shape of the cross section perpendicular to the length direction of the flow path varies depending on the microfabrication technique used, but is a trapezoidal shape or a shape close to a rectangle. When the channel width / depth (especially C, H) is made in a micro size, the solution injected by a pump or the like from the inlet 1011 and the inlet 1012 passes through the inlet channel 1013a or the inlet channel 1013b. Then, they contact at the fluid confluence 1013d, form a stable laminar flow, and flow through the reaction channel 1013c. During the laminar flow, the solutes contained in the laminar flows are mixed or reacted by molecular diffusion at the interface between the laminar flows. Solutes that are very slow to diffuse may not be mixed between laminar flows and may only be mixed after reaching the outlet 1014. When the two solutions to be injected are easily mixed in the flask, if the flow path length F is long, the flow of liquid can be uniform at the outlet, but when the flow path length F is short, Laminar flow is maintained up to the outlet. When the two solutions to be injected do not mix in the flask and are separated into layers, the two solutions naturally flow as laminar flows and reach the outlet 1014.

  FIG. 19 (a) is an explanatory view of a reactor (1020) having a cylindrical tube-type channel provided with a channel inserted on one side, and FIG. 19 (b) is a cross-sectional view taken along the line IIa-IIa of the same device. FIG. 19C is a cross-sectional view taken along the line IIb-IIb of the apparatus. The shape of the cross section perpendicular to the length direction of the flow path is a circle or a shape close thereto. When the diameter (D, E) of the cylindrical tube is a micro size, the solution injected by a pump or the like from the inlet 1021 and the inlet 1022 contacts at the fluid confluence 1023d through the inlet 1022a and the inlet 1023b. Then, a stable cylindrical laminar flow is formed and flows through the reaction channel 1023c. In the same way as the apparatus shown in FIG. 18A, the solutes contained in each laminar flow are mixed or reacted by molecular diffusion at the interface between the laminar flows while flowing as a cylindrical laminar flow. Compared with the apparatus of FIG. 18 (a), the present apparatus having a cylindrical tube type flow path can take a larger contact interface between the two liquids, and there is no portion where the contact interface contacts the apparatus wall surface. This is characterized in that there is no possibility of crystal growth from the contact portion with the wall surface, such as in the case where is produced by reaction, and the possibility of blocking the flow path is low.

  FIGS. 20 (a) and 21 show improvements to the apparatus of FIGS. 18 (a) and 19 (a) so that when the two liquid flows reach the outlet in a laminar flow, they can be separated. FIG. 20B is a cross-sectional view taken along line III-III in FIG. When these devices are used, reaction and separation can be performed simultaneously. Moreover, it can be avoided that the two liquids are finally mixed and the reaction proceeds too much or the crystal becomes coarse. When a product or a crystal is selectively present in one liquid, the product or the crystal can be obtained at a higher concentration than when the two liquids are mixed. In addition, by connecting several of these devices, there is an advantage that the extraction operation is performed efficiently.

(1) Production of organic pigment fine particle dispersion by microreactor In the present invention, an organic pigment solution uniformly dissolved in an alkaline or acidic aqueous medium is circulated in the flow path as a laminar flow, Organic pigment fine particles and a dispersion containing the same are produced by changing the hydrogen ion index (pH), which will be described in detail below.

  The organic pigment used in the present invention is not limited in hue, and may be a magenta pigment, a yellow pigment, or a cyan pigment. Specifically, perylene, perinone, quinacridone, quinacridonequinone, anthraquinone, anthanthrone, benzimidazolone, disazo condensation, disazo, azo, indanthrone, phthalocyanine, triarylcarbonium, dioxazine, aminoanthraquinone, diketopyrrolopyrrole, thioindigo, Magenta pigments such as isoindoline, isoindolinone, pyranthrone or isoviolanthrone pigments or mixtures thereof, yellow pigments, or cyan pigments.

  Preferred pigments are quinacridone, diketopyrrolopyrrole, disazo condensation, or phthalocyanine pigments, and particularly preferred are quinacridone, disazo condensation, or phthalocyanine pigments.

  In the present invention, two or more kinds of organic pigments, solid solutions of organic pigments, or combinations of organic pigments and inorganic pigments can also be used.

  The organic pigment must be uniformly dissolved in an alkaline or acidic aqueous medium, but whether it dissolves in acid or alkaline depends on which conditions the target pigment is easily dissolved. . In general, in the case of a pigment having an alkaline and dissociable group in the molecule, alkali is used, and when there is no alkaline and dissociable group and there are many nitrogen atoms in the molecule that are prone to add protons, acidity is used. For example, quinacridone, diketopyrrolopyrrole, and disazo condensation pigments are alkaline, and phthalocyanine pigments are acidic.

  The base used in the case of alkaline dissolution is an inorganic base such as sodium hydroxide, calcium hydroxide or barium hydroxide, or an organic base such as trialkylamine, diazabicycloundecene (DBU) or metal alkoxide. Are preferably inorganic bases.

  The amount of the base used is an amount capable of uniformly dissolving the pigment, and is not particularly limited, but in the case of an inorganic base, it is preferably 1.0 to 30 molar equivalents relative to the pigment, more preferably 2. It is 0-25 molar equivalent, More preferably, it is 3-20 molar equivalent. In the case of an organic base, it is preferably 1.0 to 100 molar equivalents relative to the pigment, more preferably 5.0 to 100 molar equivalents, and even more preferably 20 to 100 molar equivalents.

  The acid used for the acidic dissolution is preferably an inorganic acid such as sulfuric acid, hydrochloric acid, or phosphoric acid, or an organic acid such as acetic acid, trifluoroacetic acid, oxalic acid, methanesulfonic acid, or trifluoromethanesulfonic acid. It is an inorganic acid. Particularly preferred is sulfuric acid.

  The amount of the acid used is an amount capable of uniformly dissolving the pigment, and is not particularly limited, but is often used in an excessive amount as compared with the base. Regardless of inorganic acid or organic acid, it is preferably 3 to 500 molar equivalents, more preferably 10 to 500 molar equivalents, and further preferably 30 to 200 molar equivalents with respect to the pigment.

  Next, the aqueous medium will be described. The aqueous medium in the present invention is water alone or a mixed solvent of water-soluble organic solvents. The addition of an organic solvent is not sufficient with water alone to dissolve the pigment and dispersant uniformly, and when water alone is insufficient to obtain the viscosity required to flow through the flow path, Although it is carried out when necessary for the formation of a stream and is not always necessary, in many cases a water-soluble organic solvent is added. Examples of the organic solvent to be added include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, and acetylene glycol derivatives. , Polyhydric alcohol solvents such as glycerin or trimethylolpropane, polyvalent alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, or triethylene glycol monoethyl (or butyl) ether Lower monoalkyl ether solvent of alcohol, ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), or tri Polyether solvents such as tylene glycol dimethyl ether (triglyme), dimethylformamide, dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, urea, tetramethylurea, etc. Amide solvents, sulfur-containing solvents such as sulfolane, dimethyl sulfoxide, or 3-sulfolene, polyfunctional solvents such as diacetone alcohol and diethanolamine, acetic acid, maleic acid, docosahexaenoic acid, trichloroacetic acid, or trifluoroacetic acid. Examples thereof include carboxylic acid solvents, methanesulfonic acid, and sulfonic acid solvents such as trifluorosulfonic acid. Two or more of these solvents may be mixed and used.

  A preferred organic solvent is an amide solvent or a sulfur-containing solvent in the case of alkali, a carboxylic acid solvent, a sulfur solvent or a sulfonic acid solvent in the case of acid, and more preferably a sulfur-containing solvent in the case of alkali. If it is acidic, it is a sulfonic acid solvent. Particularly preferred is dimethyl sulfoxide (DMSO) when alkaline, and methanesulfonic acid when acidic.

The mixing ratio of water and organic solvent is a ratio that can be uniformly dissolved, and is not particularly limited. Preferably, in the case of alkaline, water / organic solvent = 0.05 to 10 (mass ratio). When an inorganic acid is used in the acidic case, it is preferable to use sulfuric acid alone, for example, without using an organic solvent. When an organic acid is used, the organic acid itself is an organic solvent, and a plurality of acids are mixed or water is added in order to adjust viscosity and solubility. Preferably, water / organic solvent (organic acid) = 0.005 to 0.1 (mass ratio).

  In the present invention, it is preferable to introduce a uniformly dissolved solution into the flow path. When the suspension is added, the particle size becomes large, or the pigment particles become wide in particle distribution. In some cases, the flow path is easily blocked. The meaning of “uniformly dissolved” is a solution in which almost no turbidity is observed when observed under visible light. In the present invention, the solution is obtained through a microfilter of 1 μm or less, or filtered when passed through a 1 μm filter. A solution containing no substance is defined as a uniformly dissolved solution.

Next, the hydrogen ion index (pH) will be described. The hydrogen ion index (pH) is a common logarithm of the reciprocal of the hydrogen ion concentration (molar concentration), and is sometimes called a hydrogen index. The hydrogen ion concentration is the concentration of hydrogen ions H + in the solution, and means the number of moles of hydrogen ions present in 1 L of solution. Since the hydrogen ion concentration varies within a very wide range, it is usually expressed using the hydrogen ion index (pH). For example, pure water contains 10 ^-7 moles of hydrogen ions at 1 atm and 25 ° C, so its pH is 7 and neutral. An aqueous solution with pH <7 is acidic, and an aqueous solution with pH> 7 is alkaline. As a method for measuring the pH value, there are a potentiometric method and a colorimetric method.

  In the present invention, the hydrogen ion index (pH) is changed in the course of flowing through the flow path to produce pigment fine particles, and the method has a flow path having an inlet different from the inlet of the uniform solution of the organic pigment, For example, it is performed using a flow path having at least two inlets as shown in FIG. 18 (a) or FIG. 19 (a). Specifically, a uniform organic pigment solution is introduced into the inlet 1011 in FIG. 18A or the inlet 1021 in FIG. 19A, and the inlet 1012 in FIG. 18A or the inlet in FIG. 19A is introduced. Hydrogen ion concentration of a solution containing an organic pigment by introducing neutral, acidic or alkaline water or an aqueous solution in which a dispersant is dissolved into the inlet 1022 and bringing both solutions into contact with each other in the channel 1013c or 1023c, That is, the hydrogen ion index (pH) is changed in the neutral (pH 7) direction. When the equivalent diameter of the channel is microscale, the Reynolds number is small, so a stable laminar flow (cylindrical laminar flow in FIG. 19A) is formed, and water and ions are passed through the stable interface between the two liquid layers. The hydrogen ion exponent (pH) of the solution containing the organic pigment gradually changes in the neutral direction after diffusion. A pigment is difficult to dissolve in an aqueous medium when it has low alkalinity or low acidity, and therefore gradually precipitates as fine particles as the hydrogen ion index (pH) of a solution containing an organic pigment changes in a neutral direction.

  The change in the hydrogen ion index (pH) is generally a change within the range of pH 16.0 to 5.0, preferably pH 16.0 when pigment fine particles are produced from a pigment dissolved in an alkaline aqueous medium. In the range of 1 to 10.0. When producing pigment fine particles from a pigment dissolved in an acidic aqueous medium, the change is generally in the range of pH 1.5 to 9.0, preferably in the range of pH 1.5 to 4.0. It is. The width of the change depends on the value of the hydrogen ion exponent (pH) of the organic pigment solution, but may be sufficient to encourage the precipitation of the organic pigment.

  The pigment fine particles generated in the microscale channel do not diffuse and flow to the outlet while being contained in one of the laminar flows, and thus have an outlet designed as shown in FIG. 20 (a) or FIG. When the flow path device is used, a laminar flow containing organic pigment fine particles can be separated. When this method is used, a concentrated pigment dispersion can be obtained, and at the same time, the water-soluble organic solvent, alkaline or acidic water used to prepare the uniform solution, and excess dispersant can be removed. . Further, the two liquids are finally mixed, so that it is possible to prevent the crystals from becoming coarse and the pigment crystals from being altered.

  The reaction temperature in the flow path in the case of producing pigment fine particles is desirably within a range where the solvent does not solidify or vaporize, but is preferably -20 to 90 ° C, more preferably 0 to 50 ° C. is there. Most preferably, it is 5-15 degreeC.

  The velocity (flow rate) of the fluid flowing in the flow path when producing pigment fine particles is advantageously 0.1 mL to 300 L / hr, preferably 0.2 mL to 30 L / hr, more preferably 0.5 mL to 15 L / hr. hr, particularly preferably 1.0 mL to 6 L / hr.

  In the present invention, the concentration range of the substrate (organic pigment and its reaction components) flowing through the flow path is usually 0.5 to 20% by mass, preferably 1.0 to 10% by mass.

  In the method for producing organic pigment fine particles of the present invention, a dispersant can be added in a solution containing an organic pigment or / and in an aqueous solution (aqueous medium) for changing the hydrogen ion index (pH). . The dispersant (1) has a function of adsorbing rapidly on the surface of the deposited pigment to form fine pigment particles, and (2) preventing these particles from aggregating again. In the present invention, as such a dispersant, an anionic, cationic, amphoteric, nonionic or pigmentary low molecular or high molecular dispersant can be used. These dispersants can be used alone or in combination. The dispersant used for dispersing the pigment is described in detail on pages 29 to 46 of “Pigment dispersion stabilization and surface treatment technology / evaluation” (Chemical Information Association, issued in December 2001).

  Examples of anionic dispersants (anionic surfactants) include N-acyl-N-alkyl taurine salts, fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphorus Examples include acid ester salts, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl sulfate ester salts, and the like. Of these, N-acyl-N-alkyltaurine salts are preferred. As the N-acyl-N-alkyltaurine salt, those described in JP-A-3-273067 are preferable. These anionic dispersants can be used singly or in combination of two or more.

  Cationic dispersants (cationic surfactants) include quaternary ammonium salts, alkoxylated polyamines, aliphatic amine polyglycol ethers, aliphatic amines, diamines and polyamines derived from aliphatic amines and fatty alcohols, fatty acids And imidazolines derived from these and salts of these cationic substances. These cationic dispersants can be used singly or in combination of two or more.

  The amphoteric dispersant is a dispersant having both an anion group part in the molecule of the anionic dispersant and a cationic group part in the molecule of the cationic dispersant.

  Nonionic dispersants (nonionic surfactants) include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, Examples thereof include glycerin fatty acid esters. Of these, polyoxyethylene alkylaryl ether is preferable. These nonionic dispersants can be used singly or in combination of two or more.

  The pigment dispersant is defined as a pigment dispersant which is derived from an organic pigment as a parent substance and is produced by chemically modifying the parent structure. For example, sugar-containing pigment dispersants, piperidyl-containing pigment dispersants, naphthalene or perylene-derived pigment dispersants, pigment dispersants having functional groups linked to the pigment parent structure through methylene groups, and polymer-modified pigment parents. Examples include a structure, a pigment dispersant having a sulfonic acid group, a pigment dispersant having a sulfonamide group, a pigment dispersant having an ether group, or a pigment dispersant having a carboxylic acid group, a carboxylic ester group, or a carboxamide group.

  Specifically, as the polymer dispersant, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyacrylamide, vinyl alcohol-vinyl acetate copolymer, polyvinyl alcohol-partial formalized product, Polyvinyl alcohol-partially butyralized, vinylpyrrolidone-vinyl acetate copolymer, polyethylene oxide / propylene oxide block copolymer, polyacrylate, polyvinyl sulfate, poly (4-vinylpyridine) salt, polyamide, polyallylamine salt, Condensed naphthalene sulfonate, styrene-acrylate copolymer, styrene-methacrylate copolymer, acrylate ester-acrylate copolymer, acrylate ester Methacrylate copolymer, methacrylate ester-acrylate copolymer, methacrylate ester-methacrylate copolymer, styrene-itaconate copolymer, itaconate-itaconate copolymer, vinyl Examples thereof include naphthalene-acrylate copolymer, vinyl naphthalene-methacrylate copolymer, vinyl naphthalene-itaconate copolymer, cellulose derivative, starch derivative and the like. In addition, natural polymers such as alginate, gelatin, albumin, casein, gum arabic, tonganto gum and lignin sulfonate can also be used. Of these, polyvinylpyrrolidone is preferable. These polymers can be used alone or in combination of two or more.

  A preferred embodiment includes an embodiment in which an anionic dispersant is contained in an aqueous medium, and a nonionic dispersant and / or a polymer dispersant is contained in a solution in which an organic pigment is dissolved.

  In order to further improve the uniform dispersibility and storage stability of the pigment, the blending amount of the dispersant is preferably in the range of 0.1 to 1000 parts by mass, more preferably 1 to 100 parts by mass of the pigment. It is the range of -500 mass parts, More preferably, it is the range of 10-250 mass parts. If the amount is less than 0.1 parts by mass, the dispersion stability of the organic pigment fine particles may not be improved.

  The dispersion containing organic pigment fine particles produced in this way can be used as it is as a pigment ink, but various additives can be added. Examples of additives include anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, antiseptics, anti-fungal agents, pH adjusters, surface tension adjusters, antifoaming agents, and viscosities. Examples thereof include a regulator, a dispersant, a dispersion stabilizer, a rust inhibitor, and a chelating agent. You may make it use, adding a pH adjuster, a penetrant, a drying inhibitor, an antiseptic | preservative, an antifungal agent, etc.

(2) Measurement of particle size, etc. of manufactured organic pigment fine particles In the fine particle measurement method, there is a method of expressing the average size of the group by quantification. Mode diameter, median diameter corresponding to the median of the integral distribution curve, and various average diameters (length average, area average, weight average, etc.). The particle size of the organic pigment fine particles produced by the method of the present invention is arbitrary as long as the flow path is not blocked, but the mode diameter is preferably 1 μm or less. Preferably it is 3 nm-800 nm, Most preferably, it is 5 nm-500 nm.

  The particle size of the fine particles is uniform, that is, the monodisperse fine particle system not only has the same size of the contained particles, but also shows no variation between particles in the chemical composition and crystal structure within the particles. Therefore, it is an important factor that determines the performance of particles. In particular, in the case of ultrafine particles having a particle size of nanometer, importance is attached as a factor governing the characteristics of the particles. The method of the present invention is an excellent method not only for controlling the size of particles but also for adjusting the size. An arithmetic standard deviation value is used as an index indicating that the sizes are uniform, and the arithmetic standard deviation value of the pigment fine particles produced according to the present invention is preferably 130 nm or less, particularly preferably 80 nm or less. The arithmetic standard deviation value is a method of obtaining the standard deviation by regarding the particle size distribution as a normal distribution, and is a value obtained by dividing the value obtained by subtracting the 16% particle size from the 84% particle size of the integrated distribution by 2.

(3) Method for Producing Quinacridone Pigment Fine Particles as an Example of Organic Pigment Fine Particles The method for producing organic pigments of the present invention can be widely applied to the above-mentioned pigments, but specifically, a method for producing unsubstituted or substituted quinacridone pigments. Explained as an example. In the present invention, the unsubstituted or substituted quinacridone pigment represented by the general formula (I) is produced in an apparatus having a flow path forming a laminar flow. The substituent of the general formula (I) will be described.

  X and Y are a fluorine atom, a chlorine atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a COORa group (where Ra is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms). ), But when a group other than a fluorine atom, a chlorine atom and a carboxyl group is described in detail, an alkyl group of methyl, ethyl, propyl or isopropyl, an alkoxy group of methoxy, ethoxy, propyloxy or isopropoxy, or methoxycarbonyl, ethoxy An alkoxycarbonyl group such as carbonyl, isopropoxycarbonyl, or octyloxycarbonyl is represented.

  X and Y are preferably a chlorine atom or an alkyl group, and particularly preferably a methyl group.

  m and n independently represent 0, 1 or 2, but preferably 1.

  Specific examples of preferred quinacridone pigments synthesized include unsubstituted or substituted quinacridones such as unsubstituted quinacridone, 2,9-dimethylquinacridone, and 4,11-dichloroquinacridone, and solid solutions thereof. I. Examples of numbers include, but are not limited to, Pigment Violet 19, Pigment Red 122, Pigment Red 207, Pigment Orange 48, Pigment Orange 49, Pigment Red 209, Pigment Red 206, and Pigment Violet 42.

The production of an unsubstituted or substituted quinacridone pigment can be carried out according to a usual synthesis method, preferably by applying it to the aforementioned apparatus having a flow path having an equivalent diameter of 10 mm or less.

  Examples of the solvent that can be used in the present invention include the aforementioned organic solvents, dispersants, surfactants, water, and combinations thereof. Further, for example, a water-soluble organic solvent added to the ink composition and other components may be further added as necessary. As these solvent components, for example, components of a pigment dispersant as described in JP-A-2002-194263 and JP-A-2003-26972 can be applied.

  The reaction fluids may be fluids that are mixed with each other or fluids that are not mixed. Mixed fluids are solutions using the same or relatively similar organic solvent, or solutions using a highly polar organic solvent such as methanol and water. Non-mixed fluids are hexane. And a solution using a low polarity solvent such as methanol and a solution using a high polarity solvent such as methanol.

  When a gas such as air or oxygen is used as the oxidizing agent, they can be dissolved in the reaction fluid or introduced as a gas into the flow path. Preferably, a method of introducing as a gas is taken.

  The reaction temperature is desirably within the range where the solvent does not coagulate or vaporize, but is preferably −20 ° C. to 250 ° C., more preferably 20 ° C. to 150 ° C., and still more preferably 40 ° C. to 120 ° C, most preferably 60 ° C to 100 ° C.

  The flow rate is advantageously between 0.1 mL and 300 L / hr, preferably between 0.2 mL and 30 L / hr, more preferably between 0.5 mL and 15 L / hr, particularly preferably between 1.0 mL and 6 L / hr.

  There are various methods for synthesizing a quinacridone pigment that can be applied to a microreactor in the present invention, and any method can be applied. As a method for producing the quinacridone pigment of the present invention, two reaction schemes are shown below as preferable reactions. The quinacridone pigment can be produced in an apparatus having a flow path with an equivalent diameter of preferably 10 mm or less, more preferably 1 mm or less.

  As a method of synthesizing by oxidation reaction of 6,13-dihydroquinacridone (Scheme 1), a method using air or oxygen (methods described in JP-A-11-209441 and JP-A-2001-115052 as reference reaction examples) ) And those using hydrogen peroxide (the method described in JP-A-2000-226530 as a reference reaction example) are preferable from the viewpoint of environmental load.

In the formula, X, Y, m and n represent the same groups as described above.

The ring-closing reaction of diarylaminoterephthalic acid or its ester (Scheme 2) is carried out using an appropriate condensing agent (methods described in JP-A-2001-335577 and JP-A-2000-103980 as examples of reference reactions). .

  In the formula, X, Y, m and n represent the same groups as described above. The substituent Rb is a hydrogen atom or an alkyl group, alkenyl group, alkynyl group, or aryl group having 1 to 10 carbon atoms. For example, examples of the alkyl group include methyl, ethyl, propyl, butyl and the like. Examples of the alkenyl group include vinyl and allyl, examples of the alkenyl group include an ethynyl group, and examples of the aryl group include a phenyl group. These substituents may further have a substituent. An aryl group is preferable, and a phenyl group is particularly preferable.

  Solvents that can be used in the quinacridone pigment include organic solvents, dispersants, surfactants, or water, and combinations thereof. Specifically, ethers such as tetrahydrofuran, dioxane, dimethoxyethane and diglyme, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone, 2-methyl-4-pentanone and cyclohexanone, ethanol, ethylene glycol and diethylene glycol Alcohols such as acetonitrile, nitriles such as acetonitrile and propionitrile, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and N, N-dimethylimidazolidone, dimethyl sulfoxide, And sulfur-containing solvents such as sulfolane. From the viewpoint of solubility of raw materials and products, amide solvents, dimethyl sulfoxide, sulfolane and the like are preferable. Further, for example, a water-soluble organic solvent added to the ink composition and other components may be further added as necessary. As these solvent components, for example, constituents of a pigment dispersant described in JP-A Nos. 2002-194263 and 2003-26972 can be applied. In addition, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, antiseptics, anti-fungal agents, pH adjusters, surface tension adjusters, antifoaming agents, viscosity adjusters, A desired ink can be obtained by further adding additives such as a dispersant, a dispersion stabilizer, a rust inhibitor, and a chelating agent.

  The reaction fluids may be fluids that are mixed with each other or fluids that are not mixed. Mixed fluids are solutions using the same or relatively similar organic solvent, or solutions using a highly polar organic solvent such as methanol and water. Non-mixed fluids are hexane. And a solution using a low polarity solvent such as methanol and a solution using a high polarity solvent such as methanol.

  When the quinacridone pigment fine particles obtained by the reaction are desired to be taken out of the dispersion, it is separated from the reaction solution by filtration or centrifugation, and washed with an amide solvent such as N, N-dimethylacetamide and obtained with high purity. It is done. Therefore, the extracted quinacridone pigment fine particles may be prepared into a favorite ink.

  The disazo condensation pigment can be produced in the same manner, but is omitted here.

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

The pH shown in the examples was measured with a glass electrode type hydrogen ion concentration meter HM-40V (measurement range pH 0 to 14) of Toa Denpa Kogyo Co., Ltd. The particle size distribution was measured with Nikkiso Co., Ltd. Microtrac UPA150. For the TEM measurement, the transmission electron microscope JEM-20 of JEOL Ltd.
00FX was used.

Example 1
1.5 g of 2,9-dimethylquinacridone was dissolved in 13.5 g of dimethyl sulfoxide, 2.68 mL of a 5 mol / L aqueous sodium hydroxide solution, and 0.75 g of a dispersant polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30) at room temperature. (IA liquid). The pH of the IA solution exceeded the measurement limit (pH 14) and could not be measured. Dispersant N-oleoyl-N-methyltaurine sodium salt 0.75 g and distilled water 90 mL were mixed (IIA solution). The pH of the IIA solution was 7.70. Impurities such as dust were removed by passing these through a 0.45 μm microfilter (Fuji Photo Film Co., Ltd.). Next, the reaction was performed by the following procedure using the reaction apparatus of FIG. Two Teflon (registered trademark) tubes with a length of 50 cm and an equivalent diameter of 1 mm are connected to the two inlets of a Teflon (registered trademark) Y-shaped connector having an equivalent diameter of 500 μm using a connector, respectively, and IA liquid and The syringe containing the IIA solution was connected and set in the pump. A Teflon (registered trademark) tube having a length of 1 m and an equivalent diameter of 500 μm was connected to the outlet of the connector. When the IA solution is sent out at a delivery rate of 1 mL / h and the IIA solution is sent out at a delivery rate of 6 mL / h, the inside of the channel becomes a laminar flow (Reynolds number: about 5.0), and a dispersion of 2,9-dimethylquinacridone is obtained. Therefore, this was collected from the tip of the tube and used as Sample 1 of the present invention. The pH of Sample 1 was 13.06. The mode diameter was 120 nm and the arithmetic standard deviation was 58 nm.

(Comparative Example 1)
Next, when the IA solution was added to 6 mL of the IIA solution in a beaker at room temperature while stirring with a stirrer, a dispersion of 2,9-dimethylquinacridone was obtained. This was designated as Comparative Sample 1. When the particle sizes and particle size distributions of the dispersions obtained in Sample 1 and Comparative Sample 1 were compared using a dynamic light scattering particle size measuring apparatus, the particle size of the dispersion in Sample 1 was the mode diameter of Comparative Sample 1. It was found that the distribution width was smaller than 144 nm and the arithmetic standard deviation of 77 nm.

(Example 2)
0.15 g of 2,9-dimethylquinacridone was dissolved in 13.35 mL of dimethyl sulfoxide, 1.65 mL of 0.8 mol / L potassium hydroxide aqueous solution, and 0.75 g of polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30) at room temperature. (IB solution). The pH of the IB solution exceeded the measurement limit and could not be measured. The IB solution and the IIA solution prepared in Example 1 were passed through a 0.45 μm microfilter (manufactured by Fuji Photo Film Co., Ltd.) to remove impurities such as dust and obtain transparent solutions. Next, the reaction was carried out by the following procedure using the reaction apparatus described below. Two Teflon (registered trademark) tubes with a length of 50 cm and an equivalent diameter of 1 mm are connected to the two inlets of a Teflon (registered trademark) Y-shaped connector having an equivalent diameter of 500 μm using a connector, and IB liquid and The syringe containing the IIA solution was connected and set in the pump. A Teflon (registered trademark) tube having a length of 1 m and an equivalent diameter of 500 μm was connected to the outlet of the connector. When the IB solution is sent at 1.0 mL / h and the IIA solution is sent at a delivery rate of 30.0 mL / h, the flow path becomes laminar (Reynolds number: about 21.9) and 2,9-dimethylquinacridone is dispersed. Since a liquid was obtained, it was collected from the tip of the tube and used as Sample 2 of the present invention. The pH of Sample 2 was 10.49. When this was measured using a dynamic light scattering particle size measuring apparatus, it was found that the mode diameter was 51 nm, the arithmetic standard deviation was 28 nm, and the distribution width was very small. Furthermore, when observed with a transmission electron microscope (TEM), it had a rounded particle shape.

(Comparative Example 2)
Next, in a beaker, 3.0 mL of the IIA solution, IB was stirred at room temperature with a stirring bar.
When 0.5 mL of the liquid was added, a dispersion of 2,9-dimethylquinacridone was obtained. This was designated as Comparative Sample 2. The pH of Comparative Sample 2 was 11.81. When this was measured using a dynamic light scattering particle diameter measuring apparatus, the mode diameter was 93 nm, the arithmetic standard deviation was 57 nm, and both the particle diameter and the distribution width were large. Furthermore, when it observed with the transmission electron microscope (TEM), it was acicular.

(Comparative Example 3)
Furthermore, the Teflon (registered trademark) tube used in the reactor of Example 2 and the Teflon (registered trademark) Y-shaped connector all had an equivalent diameter of 20 mm, the IB solution was 26.49 L / h, and the IIA solution was 122. Dispersion liquid was obtained by sending out at a feed speed of 4 L / h. The flow in the channel (Reynolds number; about 2639.6) was unstable. This was designated as Comparative Sample 3. The pH of Comparative Sample 3 was 12.56. When this was measured using a dynamic light scattering particle diameter measuring apparatus, it was found that the mode diameter was 277 nm, the arithmetic standard deviation was 140 nm, the particle diameter was large, and the distribution width was very wide.

  Comparison of Sample 2 of the present invention and Comparative Sample 2 showed that when a pigment was prepared in the flow path, the particle mode diameter and distribution width were reduced and the particle diameters were uniform. Further, the comparison between the sample 2 of the present invention and the comparative sample 3 showed that the equivalent diameter of the flow path is 10 mm or less, particularly when the scale is microscale, the particle mode diameter is small and the distribution width is considerably small.

(Example 3)
0.01 g of 2,9-dimethylquinacridone was dissolved in 10.0 mL of dimethyl sulfoxide, 0.11 mL of 0.8N aqueous potassium hydroxide solution and 0.05 g of polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30) at room temperature (IC liquid). The pH of the IC solution exceeded the measurement limit and could not be measured. This was passed through a 0.45 μm microfilter (manufactured by Fuji Photo Film Co., Ltd.) to remove impurities such as dust, and a transparent solution was obtained. Y shown in FIG. 18- (a) made of glass having channel width A: 100 μm, channel width B: 100 μm, channel width C: 100 μm, channel length F: 12 cm, channel depth H: 40 μm In a reaction apparatus having a letter-shaped channel, two Teflon (registered trademark) tubes are connected to an inlet 1011 and an inlet 1012 using connectors, and syringes each containing only IC solution and distilled water are respectively connected to the inlets 1011 and 1012. Connected and set to pump.

  A Teflon (registered trademark) tube was also connected to the discharge port 1014 using a connector. When the IC solution is sent out at a feed rate of 20 μL / min and distilled water is sent out at a rate of 20 μL / min, the inside of the channel becomes a laminar flow (Reynolds number: about 8.5), and a dispersion of 2,9-dimethylquinacridone is obtained. This was collected from the tip of the tube. The pH of this dispersion was 13.93. When this was measured using a dynamic light scattering particle size measuring apparatus, the mode diameter was 50 nm.

Example 4
Using a reactor having a cylindrical flow path as shown in FIG. 19 (a) having a flow path diameter D: 200 μm, a flow path diameter E: 620 μm, a flow path length G: 10 cm, two Teflon (registered trademark) tubes are connected to the connector. It was connected to the inlet port 1021 and the inlet port 1022, and the syringes containing the IB liquid and IIA liquid prepared in Examples 1 and 2 were connected to each other, and set in the pump. When the IB liquid is sent at a liquid feeding speed of 1.0 mL / h and the IIA liquid is sent at a liquid feeding speed of 30.0 mL / h, the inside of the flow path becomes a laminar flow (Reynolds number: about 17.7), and dispersion of 2,9-dimethylquinacridone Since a liquid was obtained, it was collected from the outlet 24. The pH of this dispersion was 10.44. When this was measured using a dynamic light scattering particle size measuring apparatus, it was found that the mode diameter was 94 nm, the arithmetic standard deviation was 77 nm, and the distribution width was very small.

(Reference Example 1)
0.01 g of 2,9-dimethylquinacridone was mixed with 10 mL of dimethyl sulfoxide, 0.04 mL of 0.8 mol / L potassium hydroxide aqueous solution and 0.05 g of polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30) at room temperature (ID liquid). The pH of the ID solution was 12.74. Although this ID solution was suspended, it was used as it was without passing through a 0.45 μm microfilter (manufactured by Fuji Photo Film Co., Ltd.). 18- (a) glass-made Y-shape having a flow path width A: 100 μm, a flow path width B: 100 μm, a flow path width C: 100 μm, a flow path length F: 12 cm, a flow path depth H: 40 μm In a reaction apparatus having a flow path, two Teflon (registered trademark) tubes are connected to an inlet 1011 and an inlet 1012 using connectors, and an ID solution and an IIA solution prepared in Example 1 are placed at the ends, respectively. The syringe was connected and set in the pump. A Teflon (registered trademark) tube was also connected to the discharge port 1014 using a connector. When the ID liquid was sent out at a liquid feed speed of 20 μL / min and the IIA liquid was sent out at a liquid feed speed of 20 μL / min, the flow path was blocked when these two liquids joined. This shows that it is important to use a uniformly dissolved solution in the method of the present invention using a reactor having a Y-shaped channel.

(Reference Example 2)
In the reaction apparatus having the cylindrical flow path shown in FIG. 19A having a flow path diameter D: 200 μm, a flow path diameter E: 620 μm, a flow path length G: 10 cm, two Teflon (registered trademark) tubes are used as connectors. Then, the syringe was connected to the inlet 1021 and the inlet 1022, and the syringes containing the ID solution prepared in Reference Example 1 and the IIA solution prepared in Example 1 were connected to each other and set in the pump. When the ID liquid was sent out at a liquid feeding speed of 1.0 mL / h and the IIA liquid was sent out at a liquid feeding speed of 30.0 mL / h, the flow path was gradually blocked at the portion where these two liquids joined. From this, it can be seen that it is important to use a uniformly dissolved solution in the method of the present invention using a reactor having a cylindrical flow path.

(Example 5)
Channel width I: 100 μm, Channel width J: 100 μm, Channel width K: 100 μm, Channel width L: 100 μm, Channel width M: 100 μm, Channel length Q: 2 cm, Channel depth S: 40 μm In the reactor that can be separated by the discharge port having the Y-shaped channel shown in FIG. 20- (a), two Teflon (registered trademark) tubes are connected to the inlet port 1031 and the inlet port 1032 using connectors. The syringe containing the IB solution prepared in Example 3 and the IIA solution prepared in Example 1 was connected to each other and set in a pump. Teflon (registered trademark) tubes were also connected to the discharge ports 1034 and 1035 using connectors. When the IB solution is sent at a rate of 10 μL / min and the IIA solution is sent at a rate of 60 μL / min, a dispersion layer of 2,9-dimethylquinacridone is laminar in the flow path (1033) (Reynolds number: about 14.9). As a result, the dispersion liquid layer could be separated into the discharge port 1034 and the other liquid layers could be separated into the discharge port 1035 at the fluid diversion point 1033e. This made it possible to obtain a highly concentrated dispersion. The pH of the sample obtained from the outlet 1034 was 12.46, and the pH of the sample obtained from the outlet 1035 was 11.74.

(Example 6)
In a reactor that can be separated by a discharge port having a cylindrical channel as shown in FIG. 21 having a channel diameter N: 100 μm, a channel diameter P: 300 μm, a channel diameter O: 100 μm, a channel length R; Two registered tubes are connected to the inlet 1041 and the inlet 1042 using connectors, and syringes containing the IC solution prepared in Example 3 and the IIA solution prepared in Example 1 are respectively connected to the inlet 1041 and the inlet 1042. Connected and set to pump. Teflon (registered trademark) tubes were also connected to the discharge ports 1044 and 1045 using connectors. When the ID solution is sent out at a feed rate of 10 μL / min and the IIA solution is sent out at a rate of 30 μL / min, the dispersion of 2,9-dimethylquinacridone in the channel (reaction channel 1043c) becomes a cylindrical laminar flow (Reynolds number: about 2). .83), the cylindrical laminar flow containing the dispersion at the fluid diversion point 1043e could be separated into the discharge port 1045, and the other liquids could be separated into the discharge port 1044. As a result, it was possible to obtain a highly concentrated dispersion using a cylindrical tube microreactor.

(Comparative Example 4)
Comparative Example of Invention According to Claim 13 IE solution obtained by removing polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30) and N-oleoyl-N-methyltaurine sodium salt from the IB solution of Example 2 and distillation Water was fed at 1.0 mL / h and 6.0 mL / h, respectively, and in the reactor used in Example 2, devices such as Teflon (registered trademark) Y-shaped connector and Teflon (registered trademark) tube were changed. The experiment was conducted without. When the obtained dispersion was measured using a dynamic light scattering particle size measuring apparatus, the mode diameter was 2.80 μm and the arithmetic standard deviation was 0.89 μm, and both the particle size and the arithmetic standard deviation were very large. This result shows that the dispersant is important for obtaining nano-sized fine particles in the present invention.

(Example 7)
Pigment Yellow 93 (1.0 g) was dissolved at room temperature in 10.0 g of dimethyl sulfoxide, 1.3 mL of a 5 mol / L sodium hydroxide aqueous solution, and 0.5 g of a dispersant polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30) (IF liquid). On the other hand, 0.5 g of dispersing agent N-oleoyl-N-methyltaurine sodium salt and 60 mL of distilled water were mixed (IIB solution). Impurities such as dust were removed by passing these through a 0.45 μm microfilter (Fuji Photo Film Co., Ltd.). Next, the reaction was performed according to the following procedure using the reaction apparatus described below. Two Teflon (registered trademark) tubes with a length of 50 cm and an equivalent diameter of 1 mm are connected to the two inlets of a Teflon (registered trademark) Y-shaped connector having an equivalent diameter of 500 μm using a connector, respectively, The syringe containing the IIB solution was connected and set in the pump. A Teflon (registered trademark) tube having a length of 1 m and an equivalent diameter of 500 μm was connected to the outlet using a connector. The IF liquid was sent out at 1 ml / h and the IIB liquid was sent out at a feeding speed of 6 mL / h, and a dispersion layer of Pigment Yellow 93 was obtained as a laminar flow (Reynolds number: about 4.9) in the flow path. This was collected from the tip of the tube. This was designated as Sample 3 of the present invention. At this time, the mode diameter was 133 nm and the arithmetic standard deviation was 69 nm.

(Comparative Example 5)
Next, when the IF solution was added to 6 mL of the IIB solution using a stirrer at room temperature, a dispersion of Pigment Yellow 93 was obtained. This was designated as Comparative Sample 4. When the pigment particle diameters of Sample 3 and Comparative Sample 4 were compared using a dynamic light scattering particle size measuring device, the mode diameter of Comparative Sample 4 was 189 nm and the arithmetic standard deviation was 98 nm. It was found that the diameter was smaller than that of the comparative sample 4 and the distribution width was small.

(Example 8)
In Example 4, 2,9-dimethylquinacridone in the IB liquid was changed to an equimolar amount of Pigment Yellow 93, and a pigment dispersion was obtained without changing other conditions. When observed with a transmission electron microscope (TEM), the primary particles had a rounded particle shape with an average particle size of 12 nm.

Example 9
In Example 4, 2,9-dimethylquinacridone in the IB liquid was changed to an equimolar amount of Pigment Red 254, and a pigment dispersion liquid was obtained without changing other conditions. When observed with a transmission electron microscope (TEM), the primary particles had a rounded particle shape with an average particle size of 9 nm.

(Example 10)
IG solution was prepared by dissolving 1.2 g of Pigment Blue 15 (manufactured by Tokyo Chemical Industry Co., Ltd.) in 10 mL of 95% sulfuric acid at room temperature. A IIC solution was prepared by mixing 6.0 g of polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30), 6.0 g of N-oleoyl-N-methyltaurine sodium salt and 240 mL of distilled water. These were passed through a 0.45 μm microfilter to remove impurities such as dust, and transparent solutions were obtained. A dispersion was prepared under the same conditions as in Example 4 except that the IB liquid used in Example 4 was changed to the IG liquid and the IIA liquid was changed to the IIC liquid. When observed with a transmission electron microscope (TEM), the average particle diameter of the primary particles had a rounded particle shape of 15 nm.

(Example 11)
Synthesis of 2,9-dimethylquinacridone by oxidation reaction 2,9-dimethyl-6,13-dihydroquinacridone, 2.0 g of 5 mol / L aqueous sodium hydroxide solution 10.0 mL and polyethylene glycol 400 18 g were added and stirred at room temperature. . The resulting dark green solution was designated as Solution A. Solution A was fed at 3.0 mL / h using a syringe pump. Moreover, 30 mass% hydrogen peroxide solution was sent as the solution B at a rate of 0.5 mL / h using a syringe pump. These A and B liquids were connected to an IMM micromixer (flow path width 45 μm, depth 200 μm), mixed in the internal microspace, and production of a bright magenta dispersion was confirmed from the outlet. As a result of analysis, 2,9-dimethylquinacridone having a purity of 96% or more was produced.

(Comparative Example 6)
To 2.0 g of 2,9-dimethyl-6,13-dihydroquinacridone, 10.0 g of 5N sodium hydroxide aqueous solution and 18 g of polyethylene glycol 400 were added and stirred at room temperature. To the obtained dark green solution, 2.0 mL of 30% by mass hydrogen peroxide was dropped, stirred at 60 ° C. for 1 hour, and cooled to room temperature. As a result of analysis, the conversion was 80%, and 2,9-dimethylquinacridone having a pigment purity of 94% or more was produced.

(Example 12)
Synthesis of 2,9-dimethylquinacridone by dehydration condensation A solution prepared by mixing 2.0 g of 2,5-di- (p-toluidino) -terephthalic acid, 0.1 g of p-toluenesulfonic acid, 15 mL of ethylene glycol and 20 mL of dimethylformamide Prepared. A fused silica glass capillary (equivalent diameter 0.20 mm, length 4.0 m) was prepared as a reactor, and 2.5 m was fixed so as to pass through the oil bath. The oil bath was heated to 150 ° C., and this solution was fed into the reactor with a syringe pump at a speed of 1.1 mL / h (residence time 5 minutes). A pigment having a bright magenta color was obtained from the capillary outlet.

(Comparative Example 7)
A solution was prepared by mixing 2.0 g of 2,5-di- (p-toluidino) -terephthalic acid, 0.1 g of p-toluenesulfonic acid, 15 mL of ethylene glycol, and 20 mL of dimethylformamide. The oil bath was heated to 150 ° C. in a 50 mL flask and stirred for 30 minutes. The produced pigment was analyzed, and a little raw material remained.

(Example 13)
Production of CI Pigment Yellow 93 by amidation reaction

   0.3 g of phenyl ester derivative (A) and 0.1 g of 3-chloro-2-methylaniline were dissolved in 20 mL of dimethylformamide. A fused silica glass capillary (equivalent diameter 0.53 mm, length 1.5 m) was prepared as a microreactor, and 1.0 m of the capillary was fixed so as to pass through the oil bath. The oil bath was heated to 150 ° C., and this solution was fed into the reactor with a syringe pump at a rate of 2.2 mL / h (residence time 6 minutes). The pigment that emerged from the capillary outlet had a bright yellow color, and as a result of analysis, the purity was 95% or more.

(Comparative Example 8)
0.3 g of phenyl ester derivative (A) and 0.1 g of 3-chloro-2-methylaniline were dissolved in 20 mL of dimethylformamide. The oil bath was heated to 150 ° C. in a 50 mL flask and stirred for 1 hour. Analysis of the resulting pigment revealed that the conversion was 65%, the pigment purity was 93% or less, and a slightly dull yellow color.

(Example 14)
Production of CI Pigment Red 214 by amidation reaction

1.0 g of phenyl ester derivative (B) and 0.2 g of 2,5-dichloro-1,4-phenylenediamine were dissolved in 50 mL of dimethyl sulfoxide. A fused silica glass capillary (equivalent diameter 0.53 mm, length 1.5 m) was prepared as a microreactor, and 1.0 m was fixed so as to pass through the oil bath. The oil bath was heated to 150 ° C., and this solution was fed into the reactor with a syringe pump at a speed of 3.3 mL / h (residence time 4 minutes). The pigment coming out from the capillary outlet had a bright red color, and as a result of analysis, the purity was 96% or more.

Synthesis of fine particles of phthalocyanine pigment (Pigment Blue 16) (Example 15)
A dark green solution prepared by dissolving 2.5 g (0.45 ml) of phthalocyanine disodium salt (Tokyo Chemicals) in dimethyl sulfoxide (DMSO) to 50 ml is a 0.5 μm Teflon (PTFE) microfilter (manufactured by Advantech) ) To obtain an IG solution. Next, a colorless transparent solution prepared by dissolving 0.5 g of polyvinyl pyrrolidone (PVP, K-90 manufactured by Wako Pure Chemical Industries, Ltd., average molecular weight 360,000) in DMSO to 50 ml was prepared from 0.5 μm Teflon (PTFE). The solution was filtered with a microfilter (manufactured by Advantech) to obtain an IH solution. Further, a colorless transparent solution prepared by dissolving 0.5 g (1.17 mmol) of N-oleoyl-N-methyltaurine sodium salt in distilled water to 50 ml was used as a 0.45 μm cellulose ester microfilter (Sartorius) for aqueous solvents. To make an IID solution.

  In the reaction apparatus having the cylindrical flow channel shown in FIG. 20A having a flow channel diameter D: 100 μm, a flow channel diameter E: 400 μm, a flow channel length G: 20 cm, the portion of the flow channel length G can be cooled to 5 ° C. A jacket that can circulate the refrigerant was installed. Two Teflon tubes were connected to the inlet 1021 and the inlet 1022 by connectors. A syringe containing a liquid obtained by mixing the IG liquid and the IH liquid in a ratio of 1: 2 (volume ratio) was connected to the introduction port 1021 and set in a syringe pump. A syringe containing the IID solution was connected to the inlet 1022 and set in a syringe pump. When the liquid was fed from the inlet 1021 at 1.0 mL / h and the inlet 1022 at a liquid feeding speed of 10.0 mL / h, the flow path cooled to 5 ° C. became laminar (Reynolds number: about 9.8). A dispersion of phthalocyanine was obtained and collected from the outlet 1024. When this was measured using a dynamic light scattering particle size measuring apparatus, a dispersion having a mode diameter of 17.4 nm and an arithmetic standard deviation of 8.6 nm and a small particle size and a very small distribution width could be obtained. .

1 is an overall configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 1 is a plan view of a main part around a printing unit of the ink jet recording apparatus shown in FIG. Plane perspective view showing structural example of print head Enlarged view of the main part of Fig. 3 (a) Plane perspective view showing another structural example of the print head Sectional view along line 4-4 in Fig. 3 (b) Block diagram of the ink supply unit of the ink jet recording apparatus shown in FIG. System configuration diagram of the ink jet recording apparatus shown in FIG. The figure explaining the droplet ejection control of the inkjet recording device which concerns on embodiment of this invention Sectional drawing which follows the 8-8 line in FIG. The figure explaining the principal part of droplet ejection control shown in FIG. Cross section of FIG. The figure explaining the result of droplet ejection control shown in FIG. Sectional view of FIG. 1 is a block diagram of a droplet ejection control unit of an ink jet recording apparatus according to an embodiment of the present invention. Graph showing the relationship between the elapsed time after landing and the diameter of the ink droplet Modification of the graph shown in FIG. The figure explaining the droplet ejection interval of a main scanning direction and a subscanning direction 6 is a flowchart showing a flow of droplet ejection control of the ink jet recording apparatus according to the present invention. (A) is explanatory drawing of the reactor which has a Y-shaped channel on one side, (b) is sectional drawing of the II line | wire of (a) (A) is explanatory drawing of the reactor which has the cylindrical tube type flow path which provided the flow path penetrated to one side, (b) is sectional drawing of the IIa-IIa line of (a), (c) is (a) ) IIb-IIb line cross section (A) is explanatory drawing of the reactor which has a Y-shaped channel on both sides, (b) is sectional drawing of the III-III line of (a) Explanatory drawing of the reaction apparatus which has the cylindrical tube type flow path which provided the flow path penetrated on both sides

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 16 ... Recording paper, 50, 50A, 50B ... Print head, 51, 51A, 51B ... Nozzle, 72 ... System controller, 80 ... Print control part, 100, 110 ... Ink droplet, 102, 112, 250, 252, 254, 256 ... dots, 200 ... droplet ejection control unit, 212 ... inequality calculation unit, 214 ... dot diameter calculation / storage unit, 216 ... timing calculation unit, 230 ... ink type information, 232 ... paper type information, D1a, D1b, D2a, D2b ... dot diameter, δT ... penetration time, 1010,1020,1030,1040 ... reactor body, 1011,1012,1021,1022,1031,1032,1041,1042 ... inlet, 1013,1033 ... Flow path, 1013a, 1013b, 1023a, 1023b, 1033a, 103 3b, 1043a, 1043b ... Introduction channel, 1013c, 1023c, 1033c, 1043c ... Reaction channel, 1013d, 1023d, 1033d, 1043d ... Fluid junction point, 1033e, 1043e ... Fluid branch point, 1033f, 1033g, 1043f, 1043g ... Discharge flow path, 1014, 1024, 1034, 1035, 1044, 1045 ... discharge port

Claims (17)

  An organic pigment solution dissolved in an alkaline or acidic aqueous medium is circulated as a laminar flow in the flow path, and the hydrogen ion index (pH) of the solution is changed in the laminar flow process. An image forming apparatus comprising a recording head for ejecting droplets containing fine organic pigment particles. An organic pigment solution dissolved in an alkaline or acidic aqueous medium is circulated as a laminar flow in the flow path, and the hydrogen ion index (pH) of the solution is changed in the laminar flow process. A recording head for ejecting droplets containing fine organic pigment particles;
An image forming apparatus comprising: a droplet ejection control unit that controls a droplet ejection timing of the recording head; and a conveyance unit that moves the recording medium and the recording head relative to the recording medium.
The distance between the first dot formed on the recording medium and the second dot formed so as to overlap the first dot after the first droplet forming the first dot is deposited. Pt, the diameter D2a of the surface of the recording medium when the second droplet forming the second dot is landed on the recording medium, and the target when the second droplet has landed on the recording medium When the diameter D1b of the first droplet on the surface of the recording medium is set, the droplet ejection control means is
D1b <2 × Pt -D2a
The droplet ejection timing is defined by the droplet diameter change time until the diameter D1b of the first droplet satisfying the condition is reached as the droplet ejection interval from the droplet ejection of the first droplet to the droplet ejection of the second droplet. An image forming apparatus that controls the image forming apparatus. The distance Pt between the first dot and the second dot, and the diameter D2a of the surface of the recording medium when the second droplet lands are as follows:
D1b <2 × Pt -D2a
Droplet ejection condition calculating means for obtaining a diameter D1b of the first droplet satisfying
Droplet diameter change time calculating means for obtaining a droplet diameter change time from when the first droplet has landed on the recording medium until the diameter of the first droplet reaches D1b;
The image forming apparatus according to claim 2, further comprising:   When a mixed pattern having a plurality of combinations of the dot interval, the first dot diameter, and the second dot diameter is formed in one image, a plurality of droplet diameter change times are calculated, and the droplet ejection control is performed. 4. The image forming apparatus according to claim 3, wherein the means controls the recording timing of the image using the calculated representative values of the plurality of droplet diameter change times.   5. The representative value of the droplet diameter change time includes at least a value equal to or greater than a maximum value of the plurality of droplet diameter change times calculated by the droplet diameter change time calculating unit. The image forming apparatus described.   6. The image forming apparatus according to claim 2, wherein the droplet ejection control unit controls the droplet ejection timing by one droplet ejection interval in one image. Comprising information providing means for providing at least liquid type information or information including any one of the recording medium type information,
The said droplet diameter change time calculation means calculates the said droplet diameter change time based on the information provided by the said information provision means, The any one of Claims 3 thru | or 6 characterized by the above-mentioned. Image forming apparatus. The droplet diameter change time calculation means is a direction substantially orthogonal to the relative transport direction of the transport means from a dot pitch in a direction substantially orthogonal to the relative transport direction of the transport means and a dot pitch in the relative transport direction of the transport means. Determining a first droplet diameter change time and a second droplet diameter change time in the relative transport direction of the transport means,
The droplet ejection control means is configured to set the first droplet diameter change time and the second droplet diameter change time to a droplet ejection interval in a direction substantially orthogonal to a relative conveyance direction of the conveyance means and a relative relationship between the conveyance means, respectively. The image forming apparatus according to claim 3, wherein the droplet ejection timing is controlled as a droplet ejection interval in the sub-scanning direction that is the transport direction.   9. The image forming apparatus according to claim 2, wherein the recording head is a line head in which a plurality of nozzles are arranged over a length corresponding to the entire width of the recording medium. . The recording head includes a first nozzle row having nozzles for ejecting droplets that form odd-numbered dots among dots formed along a direction substantially orthogonal to the relative transport direction of the transport unit; A second nozzle row having nozzles for ejecting droplets forming the second dots,
The image according to claim 9, further comprising an interval variable unit that varies an interval between the first nozzle row and the second nozzle row in accordance with droplet ejection control in the relative conveyance direction of the conveyance unit. Forming equipment.   The recording head includes a moving unit in which a plurality of the nozzles are arranged over a length shorter than the entire width of the recording medium, and the recording head and the recording medium are relatively moved along the arrangement direction of the nozzles. The image forming apparatus according to claim 2, wherein the image forming apparatus is a serial head. The recording head includes a first nozzle row having nozzles for ejecting droplets that form odd-numbered dots among dots formed along a direction substantially orthogonal to the relative transport direction of the transport unit; A second nozzle row having nozzles for ejecting droplets forming the second dots,
An interval varying means is provided for varying the interval between the first nozzle row and the second nozzle row in accordance with droplet ejection control in a direction substantially orthogonal to the relative carrying direction of the carrying means. Item 12. The image forming apparatus according to Item 11.   The image forming apparatus according to any one of claims 1 to 12, wherein the organic pigment fine particles are produced by a solution of an organic pigment containing at least one dispersant.   The image forming apparatus according to claim 1, wherein the organic pigment fine particles have a mode diameter of 1 μm or less. The image formation according to any one of claims 1 to 14, wherein the organic pigment fine particles are quinacridone pigments represented by the general formula (I), wherein the solution of the organic pigment is alkaline. apparatus.

(In the formula, X and Y are independently a fluorine atom, a chlorine atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a COORa group (where Ra is a hydrogen atom or 1 carbon atom) And m and n independently represent 0, 1 or 2.)   The droplets ejected from the recording head are alkaline, and at least a portion of the recording head that is in contact with the liquid of the droplets is formed of an alkali-resistant material. The image forming apparatus according to any one of 1 to 15. An organic pigment solution dissolved in an alkaline or acidic aqueous medium is circulated as a laminar flow in the flow path, and the hydrogen ion index (pH) of the solution is changed in the laminar flow process. A recording head for ejecting droplets containing fine organic pigment particles;
A droplet ejection control method by an image forming apparatus comprising: a droplet ejection control unit that controls ejection timing of the recording head; and a conveyance unit that moves the recording medium and the recording head relative to the recording medium. There,
A first dot forming step of forming a first dot with a first droplet on the recording medium;
A second dot depositing step of depositing a second droplet that forms a second dot that overlaps the first dot after depositing the first droplet;
When the second droplet is ejected, a droplet ejection for determining the diameter of the first droplet so that the first droplet and the second droplet do not overlap on the surface of the recording medium. A condition calculation step;
Droplet diameter change for obtaining a time from a value when the diameter of the first droplet lands on the recording medium to a value that does not overlap the second droplet on the surface of the recording medium A droplet ejection control method comprising: a time calculation step.

Images