JP2006281775A - Liquid droplet ejecting head and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a striking interference of liquid droplets ejected to overlap each other on a recording medium. <P>SOLUTION: Nozzles are arranged so that at least a part of dots formed by striking the liquid droplets including organic pigment fine particles on the recording medium overlaps in a main scanning direction. First and second nozzles which strike the dots adjacent to each other in the main scanning direction on the recording medium, and a third nozzle adjacent in a sub scanning direction to the first nozzle are arranged so that a sub scanning directional distance between the first and second nozzles becomes at least an integral multiple of not smaller than 2 of a sub scanning directional distance between the first and third nozzles. Thus a striking time difference between the ejected liquid droplet from the first nozzle and the ejected liquid droplet from the second nozzle is made long, so that the striking interference of both ejected to overlap each other is prevented. At the same time, the nozzles are arranged so that a distance in the main scanning direction between the first and third nozzles becomes at least a distance of not smaller than the maximum dot diameter of the liquid droplet ejected to the recording medium from the first nozzle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet discharge head and an image forming apparatus, and more particularly to a droplet discharge head and an image forming apparatus in which nozzles that discharge organic pigment ink as droplets are arranged in a two-dimensional matrix.

  2. Description of the Related Art Conventionally, as an image forming apparatus, an ink jet recording apparatus (ink jet printer) having an ink jet head (ink discharge head) in which a large number of nozzles are arranged is known. This ink jet recording apparatus forms an image by ejecting ink as droplets from a nozzle while moving an ink jet head and a recording medium relatively to form dots on the recording medium.

  Conventionally, various methods are known as ink ejection methods in such an ink jet recording apparatus. For example, the diaphragm constituting a part of the pressure chamber (ink chamber) is deformed by deformation of the piezoelectric element (piezoelectric actuator) to change the volume of the pressure chamber, and when the volume of the pressure chamber is increased, Ink is introduced into the pressure chamber, and when the volume of the pressure chamber is reduced, the ink is ejected as droplets from the nozzle, or the ink is heated to generate bubbles and the expansion energy when the bubbles grow. A thermal ink jet method for discharging is known.

  As described above, in the ink jet recording apparatus, one image is expressed by combining dots formed by the ink ejected from the nozzles. High image quality is achieved by reducing the size of these dots, increasing the density, and increasing the number of pixels per image.

  For example, FIG. 19 shows an enlarged example of an ink jet head in which nozzles are arranged in a two-dimensional matrix. An inkjet head 90 shown in FIG. 19 records an image by ejecting ink from nozzles 91 (91a, 91b, 91c) onto a recording medium (not shown) that is conveyed relative to the inkjet head 90. It is. The inkjet head 90 is arranged with its longitudinal direction aligned with the width direction (main scanning direction) of the recording medium perpendicular to the conveyance direction (sub-scanning direction) of the recording medium.

  A pressure chamber 92 corresponds to each nozzle 91 of the inkjet head 90. As shown in FIG. 19, the nozzles 91 are arranged in the main scanning direction and the sub-scanning direction, respectively, and are arranged in a two-dimensional matrix. At this time, the arrangement direction of the nozzles 91 in the sub-scanning direction is not completely coincident with the sub-scanning direction (perpendicular to the main scanning direction), but is arranged slightly offset from the sub-scanning direction. For example, the distance Pm in the main scanning direction between the nozzles adjacent to each other in the sub-scanning direction such as the nozzle 91a and the nozzle 91b is the distance L1 between the nozzle 91a adjacent to the nozzle 91a in the main scanning direction (substantially the size of the pressure chamber 92). Can be much smaller).

  By arranging the nozzles 91 so as to be obliquely shifted in the sub-scanning direction as described above, for example, after ejecting ink from the nozzles 91a to the recording medium to form the dots 93a, the recording medium is moved to the size of the pressure chamber 92 in the sub-scanning direction. When the ink is ejected from the nozzle 91b toward the recording medium after being conveyed by the length L2, it is formed as a dot 93b immediately next to the main scanning direction of the dot 93a previously formed by the nozzle 91a. The distance between the dots (center-to-center distance) is equal to the distance Pm in the main scanning direction between the nozzles (91a and 91b) adjacent to each other in the sub-scanning direction described above. Thus, by arranging the nozzles 91 in a matrix and obliquely shifted, the nozzles (the same thing, but dots formed by the nozzles) can be densified.

  For example, Patent Document 1 describes an arrangement in which nozzles are arranged in a two-dimensional matrix of n rows and m columns in this way to reduce the connection to each individual electrode and increase the density. Yes.

  In the line-type inkjet head, the head chips in which a plurality of ink nozzles are arranged in a row are arranged on the same substrate in two rows in a staggered manner at an angle with respect to the line arrangement direction. (For example, see Patent Document 2).

  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 the permeability to paper is reduced and an image with high saturation cannot be obtained.

As a countermeasure against this, Patent Document 3 proposes a method of making pigment fine particles using a microjet reactor method. In this method, the solution in which the pigment is dissolved and the 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-T 9-507803 Publication JP 2002-273878 A 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, when the nozzle density is increased, in the line head type high-speed ink jet printing, the interval between droplets is very short, so that the droplets ejected onto the recording medium stick to each other before fixing on the recording medium. Overlapping and agglomerating, the shape of one large droplet or dot breaks down and penetrates into the recording medium. Is caused. This combination of droplets occurs not only in the sub-scanning direction, which is the conveyance direction of the recording medium, but also in the main scanning direction orthogonal thereto, and is particularly large when such droplet combination occurs two-dimensionally. Image degradation occurs. Further, in the conventional ink jet head as shown in FIG. 19 described above, the nozzles are simply arranged obliquely in the sub-scanning direction, so that ink droplets adjacent in the main scanning direction on the recording medium. There is a problem in that after landing on the recording medium, they are combined with each other before fixing, resulting in large droplets causing image quality degradation.

  In addition, the one described in Patent Document 1 simply arranges the nozzles in a two-dimensional matrix, and there is no particular reference to the nozzle arrangement, and there is a problem similar to that of the conventional inkjet head.

  Further, the one described in Patent Document 2 is intended to increase the density in the line type head, and does not describe the relationship between the dot diameter and the nozzle arrangement for preventing landing interference. Therefore, when printing is performed with a line-type head having a nozzle arrangement as described in Patent Document 2, the distance in the main scanning direction is from adjacent nozzles as in the conventional simple matrix head as shown in FIG. There is a problem that the discharged dots may be combined and aggregated before being fixed on the recording medium, and image quality may be deteriorated.

  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. Therefore, it is an object of the present invention to provide a droplet discharge head and an image forming apparatus that can obtain a high-definition image with high saturation with pigment ink.

  In order to achieve the above object, the invention according to claim 1 is directed to a recording medium in which a solution of an organic pigment dissolved in an alkaline or acidic aqueous medium is circulated in a flow path as a laminar flow. Recording head for ejecting droplets containing organic pigment fine particles generated by the process of changing the hydrogen ion index (pH) of the solution, wherein the recording medium is conveyed relative to the droplet ejection head At least a portion of the dots that have been ejected onto the recording medium from the nozzle in a two-dimensional manner in the main scanning direction orthogonal to the transport direction and the sub-scanning direction that is the transport direction. The nozzles are arranged, and the first nozzle, the second nozzle, and the third nozzle that are adjacent to the first nozzle in the sub-scanning direction are ejected on the recording medium. Whereas The distance between the first nozzle and the second nozzle in the sub-scanning direction is at least an integer multiple of 2 or more of the distance between the first nozzle and the third nozzle in the sub-scanning direction. The first nozzle and the second nozzle are arranged apart from each other in the sub-scanning direction, and the distance between the first nozzle and the third nozzle in the main scanning direction is at least the first nozzle and the first nozzle. The first nozzle and the third nozzle are arranged apart from each other in the main scanning direction so that the distance is equal to or larger than the maximum dot diameter formed by droplets ejected from the three nozzles onto the recording medium. A droplet discharge head is provided.

  According to a second aspect of the present invention, the distance in the main scanning direction between the first nozzle and the third nozzle is at least in the main scanning direction between the first nozzle and the second nozzle. The distance is an integer multiple of 2 or more.

  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 carried out 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 organic pigment fine particles having a more uniform particle diameter 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, a high-definition image with high saturation can be obtained. 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.

  Furthermore, by arranging the nozzles as described above, it is possible to reliably prevent landing interference between adjacent droplet dots in the main scanning direction.

  Similarly, in order to achieve the above object, the invention according to claim 3 circulates a solution of an organic pigment dissolved in an alkaline or acidic aqueous medium as a laminar flow in a flow path on a recording medium, A recording head for ejecting droplets containing organic pigment fine particles generated by a process of changing the hydrogen ion index (pH) of a solution in the laminar flow process, wherein the recording medium is applied to the droplet ejection head At least some of the droplet dots ejected onto the recording medium in a two-dimensional manner in the main scanning direction orthogonal to the relatively transporting direction and the sub-scanning direction, which is the transport direction, are formed on the recording medium. The nozzles are arranged so as to overlap in the main scanning direction, and the minimum distance between the nozzles in the main scanning direction, which is the minimum distance in the main scanning direction between the nozzles in the droplet discharge head, is Pm, and is arranged in one row in the main scanning direction. A plurality of arranged nozzle rows are shifted in the main scanning direction and arranged adjacent to each other in the sub scanning direction, and arranged so that there is always a nozzle row shifted by a predetermined distance in the main scanning direction with respect to an arbitrary nozzle row. Among the plurality of nozzle blocks formed in this manner, the nozzle blocks adjacent in the sub-scanning direction are shifted by a predetermined interval in the sub-scanning direction and are shifted by the minimum inter-nozzle distance Pm in the main scanning direction in the main scanning direction. A droplet discharge head is provided.

  Further, according to a fourth aspect of the present invention, the predetermined distance for shifting the nozzle row in the main scanning direction is N × Pm using the minimum inter-nozzle distance Pm in the main scanning direction and the number N of the nozzle blocks. It is preferable to set to.

  Further, according to a fifth aspect of the present invention, the predetermined interval in the sub-scanning direction between the nozzle blocks is a distance between nozzles Ps in the sub-scanning direction that is a distance between nozzles adjacent in the sub-scanning direction in the nozzle array, and It is preferable to set M × Ps by using the number M of the nozzle rows constituting each nozzle block.

  According to this, since the nozzle arrangement pitch in the sub-scanning direction is unified, nozzle drive control can be simplified.

  According to a sixth aspect of the present invention, the first nozzle block and the second nozzle block each having a first nozzle and a second nozzle for ejecting droplet dots that overlap in the main scanning direction on the recording medium. At least the first dots landed from the first nozzle are fixed on the recording medium and the droplet diameter on the surface of the recording medium is smaller than the predetermined interval in the sub-scanning direction between The recording medium is timed until it becomes small and does not come into contact with a droplet on the recording medium surface of the second dot landing from the second nozzle after landing of the first dot. Is set in accordance with at least the type of the recording medium.

  According to this, by taking into consideration the dependency of the ink fixing time on the recording medium, it becomes possible to prevent the landing interference of dots in the main scanning direction with respect to various recording media, and high-quality recording can be obtained. .

  According to a seventh aspect of the present invention, when the maximum dot diameter of droplets ejected onto the recording medium from any nozzle constituting the nozzle array is Dmax, the minimum inter-nozzle distance Pm in the main scanning direction On the other hand, the number N of nozzle blocks is set so that Dmax ≦ N × Pm. According to this, it is possible to prevent landing interference between dots that land with a short time difference from the nozzles arranged adjacently in the sub-scanning direction.

  Similarly, in order to achieve the above-mentioned object, the invention according to claim 8 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 in a recording medium. A recording head for ejecting droplets containing organic pigment fine particles generated by a process of changing the hydrogen ion index (pH) of a solution in the laminar flow process, wherein the recording medium is applied to the droplet ejection head At least a portion of the dots ejected onto the recording medium from the nozzles in a two-dimensional manner in the main scanning direction orthogonal to the relatively transporting direction and the sub-scanning direction, which is the transport direction, is main-scanned. The nozzles are arranged so as to overlap in the direction, and the first nozzle and the second nozzle that eject the first dot and the second dot that eject droplets adjacent to or overlap each other in the main scanning direction on the recording medium And sub-scanning direction At least the second dot is landed and fixed after the first dot has landed on the recording medium and the droplet diameter on the surface of the recording medium has decreased, and the first dot has landed. The first nozzle and the sub-scanning direction are set so as to be equal to or longer than the distance at which the recording medium is relatively transported in the time until the dot reaches a size that does not contact the droplet on the recording medium surface. The distance in the main scanning direction from the third nozzle adjacent to the nozzle is at least equal to or larger than the maximum dot diameter formed by ejecting droplets from the first nozzle and the third nozzle onto the recording medium. Provided is a droplet discharge head characterized in that the first nozzle and the third nozzle are arranged.

  Thereby, landing interference between adjacent dots can be effectively prevented.

  Further, as shown in claim 9, in the invention according to any one of claims 1 to 8, the organic pigment fine particles are produced by a solution of an organic pigment containing at least one dispersant. Yes.

  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.

  Moreover, as shown in claim 10, in the invention described in any one of claims 1 to 9, 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.

  In addition, as shown in claim 11, in the invention according to any one of claims 1 to 10, the organic pigment fine particle is a quinacridone type represented by the general formula (I), wherein the organic pigment solution is alkaline. It is characterized by being a pigment.

  According to the eleventh aspect, among the pigments used in the pigment ink, a quinacridone pigment is preferable, and the quinacridone pigment is used to form fine particles.

  According to a twelfth aspect of the present invention, in the invention according to any one of the first to eleventh 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 made of an alkali-resistant material, the alkaline organic pigment solution can be used as it is like a quinacridone pigment. Can be used and convenient.

  Similarly, in order to achieve the object, an invention according to claim 13 is an image forming apparatus comprising the droplet discharge head according to any one of claims 1 to 12. provide.

  As a result, landing interference between adjacent dots is prevented, and high-quality image recording can be performed.

  According to the present invention, a pigment ink containing fine pigment particles having fine particle diameter and excellent monodispersibility can be ejected from a recording head, and the landing time interval of droplets ejected from different nozzles overlapping each other on the recording medium can be reduced. The length can be increased, landing interference can be prevented, and bleeding can be eliminated, so that a high-definition image with high saturation can be obtained with pigment ink.

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

  Of the pigment ink, the droplet discharge head, and the image forming apparatus that characterize the present invention, the droplet discharge head and the image forming apparatus will be described first.

[Configuration of droplet discharge head and image forming apparatus]
When the nozzles are arranged in a two-dimensional matrix, the nozzles are not simply arranged obliquely as in the prior art, but different nozzles are arranged by shifting them from each other as described in detail below. The time interval at which droplets ejected from the recording medium and overlapping on the recording medium are ejected is increased to prevent landing interference between adjacent dots.

  FIG. 1 is an overall configuration diagram showing an outline of an ink jet recording apparatus as an embodiment of an image forming apparatus according to the present invention.

  As shown in FIG. 1, the ink jet 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, And a paper discharge unit 26 for discharging the printed recording paper (printed material) 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.

  In the case of an apparatus configuration using roll paper, a 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 arranged on the print surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  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.

  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 flat ( Flat surface).

  The belt 33 has a width that is wider 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.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 is driven in the clockwise direction in FIG. The recording paper 16 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 blowing method of spraying 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 printing area, the roller comes into contact with the printing surface of the paper immediately after printing, so that the image blurs. There is a problem that it is easy. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing 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 print unit 12 includes print heads 12K, 12C, 12M, and 12Y corresponding to four colors (KCMY). Each of the print heads 12K, 12C, 12M, and 12Y has a plurality of ejection ports (nozzles), and is recorded. The longitudinal directions of the print heads 12K, 12C, 12M, and 12Y are arranged side by side in the width direction (main scanning direction) of the recording paper 16 orthogonal to the paper transport direction (sub-scanning direction) so as to bear the entire width of the paper 16. This is a so-called full-line type head having a length corresponding to the maximum paper width (see FIG. 2).

  As shown in FIG. 2, each of the print heads 12K, 12C, 12M, and 12Y has an ink discharge port (nozzle) over a length exceeding at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. A plurality of line-type heads are arranged in the longitudinal direction.

  As will be described in detail later, each of the print heads 12K, 12C, 12M, and 12Y includes a detection means for detecting ink ejection, an optical system for forming a light beam for detection in a predetermined shape, and other inks. Various means relating to detection of the discharge state, ink droplet size, ink discharge speed, and the like are provided.

  A print head corresponding to each color ink in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side (left side in the figure) along the conveyance direction (paper conveyance direction) of the recording paper 16 12K, 12C, 12M, and 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.

  Thus, according to the printing unit 12 in which the full line head that covers the entire area of the paper width is provided for each ink color, the operation of relatively moving the recording paper 16 and the printing unit 12 in the paper transport direction is performed once. It is possible to record an image on the entire surface of the recording paper 16 only by performing (that is, by one scanning). Thereby, printing can be performed at a higher speed than the shuttle type head in which the print head reciprocates in the direction orthogonal to the paper conveyance 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 has a pipeline that is 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, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. is doing.

The print detection unit 24 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the print unit 12, and means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor. Function as.

  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 includes 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 patterns printed by the print heads 12K, 12C, 12M, and 12Y for the respective colors, and detects ejection of the print heads 12K, 12C, 12M, and 12Y. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  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. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with a selecting means (not shown) for switching the paper discharge path in order to select the printed matter of the main image and the printed matter of the test print and send them to the respective discharge portions 26A and 26B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a 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, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

In this embodiment, as shown in FIG. 2, the print heads 12K, 12C, 12M, and 12Y have ink ejection ports (nozzles) extending over at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. ) Are arranged as a full line type head, but as shown in FIG. 3, short two-dimensionally arranged heads 50 'are arranged in a staggered manner and connected to form the full width of the recording medium. A corresponding length may be used. In this case, the nozzle arrangement of the present embodiment is applied to each short head 50 ′.

  Next, the structure of the print head will be described. Since the structures of the print heads 12K, 12C, 12M, and 12Y provided for each ink color are common, the following description will be made by using a single print head 50 as a representative.

  FIG. 4 is an enlarged plan view showing one pressure chamber unit 54 constituting the print head 50. As shown in FIG. 4, the pressure chamber unit 54 includes a pressure chamber 52 having a nozzle 51 for discharging ink and an ink supply port 53. The pressure chamber 52 provided for each nozzle 51 has a substantially square planar shape, and nozzles 51 and ink supply ports 53 are provided at both corners on the diagonal line. Each pressure chamber 52 communicates with a common flow path (not shown in FIG. 4) via an ink supply port 53.

  FIG. 5 is a cross-sectional view of the pressure chamber unit 54 taken along the line VV in FIG. As shown in FIG. 5, an actuator 58 having individual electrodes 57 is joined to a diaphragm 56 that forms the top surface of the pressure chamber 52. By applying a driving voltage to the individual electrode 57, the actuator 58 is deformed and ink is ejected from the nozzle 51 communicating with the pressure chamber 52.

  On the other hand, the pressure chamber 52 communicates with the common channel 55 through the ink supply port 53, so that when ink is ejected, new ink is supplied from the common channel 55 to the pressure chamber 52 through the ink supply port 53. It has become.

  In the above, the transport direction of the recording medium is the sub-scanning direction, and the width direction of the recording medium (print head longitudinal direction) orthogonal to the main scanning direction is the main scanning direction. The concept is explained here.

  When the nozzles are driven by a full line head having a nozzle row corresponding to the entire width of the recording medium (recording paper 16), (1) all the nozzles are driven simultaneously, (2) the nozzles are sequentially driven from one side to the other, ( 3) There is a driving method such as dividing nozzles into blocks and sequentially driving the nozzles in each block from one side to the other, and the width direction of the recording medium (direction perpendicular to the recording medium conveyance direction). A nozzle driving method that prints one line or one band is defined as main scanning.

  Further, by relatively moving the above-described full line head and the recording medium, printing of one line (a line formed by one line of dots or a line composed of a plurality of lines) formed by the above-described main scanning is repeated. The nozzle driving method to be performed is defined as sub-scanning.

  FIG. 6 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10 of the present embodiment. 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 58 of the print heads 12K, 12C, 12M, and 12Y of the respective colors 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.

  The nozzle arrangement in the print head 50, which is the point of the present invention, will be described in detail below.

  FIG. 7 shows an enlarged plan view of a part of the nozzle array in the print head 50 of the present embodiment. As described above, the print head 50 of the present embodiment is arranged with its longitudinal direction aligned with the width direction of the recording paper 16, and recording is performed in a direction (short direction) perpendicular to the longitudinal direction of the print head 50. The paper 16 is conveyed. Therefore, the longitudinal direction of the print head 50 is the main scanning direction, and the short direction is the sub-scanning direction. The print head 50 realizes a two-dimensional matrix arrangement of the nozzles 51 by arranging the pressure chambers 52 having the nozzles 51 in a two-dimensional matrix in the main scanning direction and the sub-scanning direction as described below. In FIG. 7, only 20 pressure chambers 52 are arranged in the sub-scanning direction due to the display relationship, but more actual pressure chambers 52 are repeatedly arranged in the main scanning direction in the actual print head 50. ing.

  Further, as shown in FIG. 4, the pressure chambers 52 are substantially square, but in FIG. 7, the size of each pressure chamber 52 in the sub-scanning direction is reduced to 1/20 with respect to the main scanning direction. it's shown. In addition, the lower left part in FIG. 7 is enlarged to FIG. 8 (the vertical and horizontal sizes of the pressure chambers 52) are displayed at a normal scale.

  FIG. 7 shows only the leftmost pressure chamber 52 in the main scanning direction. In the example shown in FIG. 7, the print head 50 has 20 pressure chambers 52 (52-11A, 52-12A,..., 52-21A,...) Arranged in the sub-scanning direction. Each pressure chamber 52 has a nozzle 51 (51-11A, 51-12A,...) At a fixed location in the lower left corner.

Accordingly, the print head 50 includes 20 nozzles 51 (51-11A, 51 in the sub-scanning direction).
-12A,..., 51-21A,. Also, as shown in FIG. 8, a large number of pressure chambers 52 and nozzles 51 are arranged in the main scanning direction. For example, in FIG. 8, the pressure chamber 52 is lined up with pressure chambers 52-11A, 52-11B, 52-11C,... In the column in the scanning direction, the pressure chambers 52 are aligned with the pressure chambers 52-12A, 52-12B, 52-12C,.

  Similarly, the nozzles 51 are also arranged in the lowermost row in the main scanning direction from the left side with nozzles 51-11A, 51-11B, 51-11C,..., And the upper row in the main scanning direction. In the row, nozzles 51-12A, 51-12B, 51-12C,... Are arranged from the left side.

  As described above, in this embodiment, the nozzles 51 are arranged in a row of the nozzles 51 in which a large number of nozzles 51 are arranged in one row in the main scanning direction, for example, the nozzles 51-11A, 51-11B, 51-11C,. That's it.

  In the example shown in FIG. 7, such nozzle rows in which a large number of nozzles 51 are arranged in the main scanning direction are arranged in 20 rows in the sub scanning direction, and these 20 nozzle rows arranged in the sub scanning direction are arranged in the sub scanning direction. Is divided into four nozzle rows arranged adjacent to each other. Then, four nozzle rows (for example, four nozzle rows in which the leftmost nozzle 51 is 51-11A, 51-12A, 51-13A, 51-14A, respectively) Therefore, in the example shown in Fig. 7, all the nozzles displayed in Fig. 7 are divided into five nozzle blocks.

  In FIG. 8, four nozzle rows, which are adjacent to each other in the sub-scanning direction from the bottom and arranged obliquely upward, (51-11A, 51-11B, 51-11C,...), (51- 12A, 51-12B, 51-12C, ...), (51-13A, 51-13B, 51-13C, ...), (51-14A, 51-14B, 51-14C, ...) The nozzle block consisting of the nozzle block 1 is referred to as a nozzle block 1, and the nozzle block including four nozzle rows arranged obliquely adjacent to each other in the sub-scanning direction is referred to as a nozzle block 2. Similarly, the print head 50 is constituted by five nozzle blocks each having four nozzle rows.

  As shown in FIG. 7, each nozzle row in the nozzle block 1 is subjected to main scanning as shown by the leftmost nozzles 51-11A, 51-12A, 51-13A, 51-14A representing each nozzle row. They are arranged obliquely adjacent to each other in the sub-scanning direction and shifted by a distance Lm in the direction. The same applies to other nozzle blocks 2 and the like. Further, the nozzle block 1 and the nozzle block 2 are arranged so as to be shifted by a distance Pm in the main scanning direction and by a distance Ls in the sub-scanning direction, as indicated by the corresponding nozzles 51-11A and 51-21A. ing.

  This distance Pm in the main scanning direction is the minimum inter-nozzle distance in the main scanning direction of the nozzle array in the print head 50 of this embodiment. In the present embodiment, dots adjacent in the main scanning direction on the recording paper 16 are ejected by nozzles 51 (for example, nozzles 51-11A and 51-21A) arranged adjacent to each other in the main scanning direction. The minimum inter-nozzle distance Pm in the direction is equal to the minimum inter-dot distance Pd on the recording paper 16.

  In general, as shown in FIG. 9A, the minimum inter-nozzle distance Pm between two nozzles N100 and N102 adjacent in the main scanning direction is two dots D100 adjacent in the main scanning direction on the recording paper 16. , D102 is equal to the minimum inter-dot distance (dot pitch) Pd. However, the minimum inter-nozzle distance Pm and the minimum inter-dot distance Pd are not always equal. That is, as shown in FIG. 9B, the minimum nozzle distance Pm between the two nozzles N100 and N102 in the main scanning direction is larger than the minimum dot distance Pd between the two dots D100 and D102 in the main scanning direction. , Pm = 2 × Pd, the number of nozzles is reduced to configure the print head, and the print head is intermittently moved forward in the main scanning direction during printing to shift the nozzle position to the dot position to be recorded. It is also possible to eject droplets. If it does in this way, when the position which should record the 1st dot D100 on a recording medium is conveyed to the position of the nozzle N100 first, it will eject from the nozzle N100 as it is, and the 1st dot D100 will be formed. Next, at the timing when the position where the second dot D102 on the recording medium is to be recorded is conveyed in the main scanning direction of the nozzle N102, the print head is stepped leftward in FIG. 9B by the distance Pd. By ejecting the second dot D102 from the second nozzle N102, overlapping dots D100 and D102 similar to those in FIG. 9A can be formed. In this case, the minimum inter-nozzle distance Pm and the minimum inter-dot distance Pd are not equal.

  In order to describe the nozzle arrangement in the present embodiment in more detail, the lower left portion of FIG. 7 is enlarged and shown in FIG. In FIG. 8, the size of each pressure chamber 52 (52-11A,...) Is represented at the same scale in the vertical and horizontal directions (main scanning direction and sub-scanning direction).

  The distance between adjacent nozzles in the sub-scanning direction in each nozzle block, for example, the distance Ps in the sub-scanning direction between the nozzles 51-11A and 51-12A of the nozzle block 1 in FIG. 8 is the minimum inter-nozzle distance in the sub-scanning direction. (Nozzle pitch in the sub-scanning direction). To be precise, the thickness of the partition between the pressure chambers must be taken into consideration, but here it is assumed to be approximately equal to the length L2 of the pressure chamber 52-11A in the sub-scanning direction.

  When the length of the pressure chamber 52-11A in the main scanning direction is L1, the minimum arrangement interval of the nozzles in each nozzle row (for example, between the nozzles 51-11A and 51-11B). The distance) is approximately L1. As described above, since the pressure chamber 52 is approximately square, it may be considered that L1 = L2.

  The distance Ls between the nozzle block 1 and the nozzle block 2 in the sub-scanning direction is the minimum number of nozzles Ps in the sub-scanning direction in the nozzle arrangement in the present embodiment multiplied by the number of nozzle rows (positive integer M) constituting the nozzle block. is there. That is, Ls = M × Ps. As shown in FIG. 8, in this example, each nozzle block is composed of four nozzle rows in the sub-scanning direction (for example, in the nozzle block 1, the leftmost nozzle 51 has nozzles 51-11A and 51-12A, respectively). , 51-13A, 51-14A, and four nozzle rows). Therefore, M = 4 and Ls = 4 × Ps.

  The nozzle 51-11A of the nozzle block 1 and the nozzle 51-21A of the nozzle block 2 have the distance in the main scanning direction being the minimum inter-nozzle distance Pm in the nozzle arrangement of this example, and the recording paper ejected by the nozzle 51-11A The dots on 16 overlap the dots that are transported by the distance Ls, which is the distance between the nozzle blocks in the sub-scanning direction, and ejected by the nozzle 51-21A. Therefore, the distance between the nozzles 51-11A and 51-21A for ejecting dots that overlap in the main scanning direction on the recording paper 16 is four times that of the conventional nozzle arrangement shown in FIG. . Therefore, if the conveyance speed of the recording paper 16 is the same as that in the conventional case, the time interval at which the droplets adjacent in the main scanning direction on the recording paper 16 land is simply the conventional arrangement in which the nozzles are diagonally arranged as shown in FIG. This is four times the case, and landing interference does not occur even if droplets are stacked and ejected.

The distance Lm in the main scanning direction between the nozzles adjacent in the sub-scanning direction in the nozzle block is set to be an integer N times the minimum inter-nozzle distance Pm in the main scanning direction in the nozzle arrangement of this example. . That is, Lm = N × Pm. Specifically, in this embodiment, as shown in FIG. 7, four dots adjacent to each other in the main scanning direction correspond to the dots on the recording paper 16 ejected by the nozzles 51-11A. -21A, 51-31A, 51-41A, 51-51A. Therefore, the nozzles 51-11A and 51-12A adjacent to each other in the sub-scanning direction in the nozzle block 1 are arranged apart from each other by five nozzles belonging to the five nozzle blocks in the main scanning direction. Therefore, N is the number of nozzle blocks. In the example shown in FIG. 7, N = 5 and Lm = 5 × Pm. Thus, Dmax ≦ Lm with respect to the maximum dot diameter Dmax. The same applies to other nozzles in the nozzle block 1 and other nozzle blocks.

  In the present embodiment, the nozzles are arranged in this way to prevent landing interference. Generally, the conveyance speed of the recording medium is V [μm / μsec], and the length of the pressure chamber 52 in the sub-scanning direction. Is set to L2 [μm] (L2≈Ps), the landing time difference of droplet dots ejected from the nozzle separated by M nozzles in the sub-scanning direction to the same position in the sub-scanning direction on the recording medium is Δt = It is given by (M × L2) / V [μsec]. Therefore, if the time until the ejected dots are fixed on the recording medium is t0 [μsec], the two dots are fixed without interfering with each other if Δt> t0.

  In the conventional simple matrix arrangement shown in FIG. 19, M = 1, but landing interference is prevented by setting the value of M so as to satisfy the condition of Δt> t0. As described above, in this embodiment, M = 4, and the time interval for landing of adjacent droplets is set to be four times that of the prior art, thereby increasing the landing time difference to satisfy this.

  Further, nozzles in the sub-scanning direction (minimum inter-nozzle distance Ps in the sub-scanning direction in this nozzle array) are present at the same position in the sub-scanning direction (for example, nozzle 51-11A and nozzle 51-11B in FIG. 8). ) In the main scanning direction. That is, in FIG. 8, it is assumed that the size of the pressure chamber 52 is the same in the main scanning direction (horizontal) and the sub-scanning direction (vertical) (L1 = L2). By setting L1 = L2 (or L1≈L2), it becomes possible to secure the displacement amount of the actuator and prevent the bubble flow in the pressure chamber.

  For example, it is assumed that L1 = L2 = 200 [μm]. Further, in the case of FIG. 8 in which 20 nozzles (nozzle rows) are arranged in the sub-scanning direction, the nozzle density in the main scanning direction is 2400 [dpi], the ejection frequency is 10 [kHz], that is, the conveyance speed of the recording medium is set. Assuming 100 [mm / sec], when the landing time interval of droplets adjacent in the main scanning direction is calculated on a recording medium ejected from nozzles adjacent in the main scanning direction, the nozzles are simply tilted as in the conventional case. In the case of just arranging them, 0.2116 [mm] / 100 [mm / sec] = 2.116 [msec], whereas the arrangement of this embodiment as shown in FIG. In this case, 0.2116 × 4 [mm] / 100 [mm / sec] = 8.464 [msec].

  FIG. 10 shows another example of the nozzle arrangement in the droplet discharge head (print head) of this embodiment. FIG. 10 also shows the size of the pressure chamber in the sub-scanning direction reduced to 1/20 with respect to the main scanning direction, as in FIG. As shown in FIG. 10, this nozzle arrangement is the same as the nozzle arrangement shown in FIG. 7, except that the second and third nozzle rows in the sub-scanning direction of each nozzle block are interchanged. For example, the nozzle block 1 in FIG. 10 is obtained by replacing the nozzle array including the nozzles 51-12A and the nozzle array including the nozzles 51-13A in the nozzle block 1 illustrated in FIG. At this time, the arrangement of the nozzle rows is similarly changed in the other nozzle blocks.

  This nozzle row replacement is performed only within each nozzle block, and the relationship between the nozzle blocks is exactly the same as in the case of FIG. For example, the relationship between the nozzle 51-11A in the nozzle block 1 and the corresponding nozzle 51-21A in the nozzle block 2 (the distance in the main scanning direction and the sub-scanning direction) is the same as that described in FIG. Exactly the same.

Further, a nozzle adjacent to each nozzle in the main scanning direction in the nozzle block means a nozzle having a minimum distance in the main scanning direction with respect to the nozzle in the same nozzle block. For example, in FIG. 10, for the nozzle 51-11A of the nozzle block 1, the nozzle having the smallest distance in the main scanning direction is 51-12A, so the adjacent nozzle in the nozzle block 1 of the nozzle 51-11A is Not nozzle 51-13A but nozzle 51-12A.

  Similarly, in the nozzle block 1, the nozzle 51-13A is a nozzle adjacent to the nozzle 51-12A in the main scanning direction, and the nozzle 51-14A is a nozzle adjacent to the nozzle 51-13A in the main scanning direction. . As shown in FIG. 10, the distance in the main scanning direction between adjacent nozzles in these main scanning directions is Lm as in the case of FIG.

  The distance Lm between adjacent nozzles in the main scanning direction in the same nozzle block is a positive integer N times the minimum inter-nozzle distance Pm in the main scanning direction in this nozzle array, that is, Lm = N × Pm. Is set. In the case of FIG. 10, similarly to FIG. 7, the nozzle block is formed of five nozzles, and N = 5, so Lm = 5 × Pm.

  In the example shown in FIG. 7, the plurality of nozzle rows constituting each nozzle block are arranged adjacent to each other in the sub-scanning direction while being shifted by a predetermined distance Lm in the main scanning direction, whereas in the example shown in FIG. Regardless of whether or not the plurality of nozzle rows constituting each nozzle block are adjacent to each other in the sub-scanning direction, they are arranged to be adjacent to each other at a predetermined distance Lm in the main scanning direction. In this way, in FIG. 10, the nozzle rows in each nozzle block are not arranged stepwise as in FIG. 7, but are arranged in the sub-scanning direction while being alternately shifted in the main scanning direction. Is configured.

  Another way of looking at the nozzle arrangement shown in FIG. 10 is also possible. That is, the nozzle arrangement shown in FIG. 11 is the same as the nozzle arrangement shown in FIG. 10, but each nozzle is not divided into nozzle blocks formed by four nozzle rows as shown in FIG. A group of nozzles formed by the nozzles 51-11A, 51-21A, 51-31A, 51-41A, and 51-51A is distinguished from the nozzle block of FIG. 10 and is referred to as a nozzle group. For example, a nozzle group formed by the nozzles 51-11A, 51-21A, 51-31A, 51-41A, 51-51A is a nozzle group B1, and the nozzles 51-13A, 51-23A, 51-33A, 51-43A , 51-53A is a group of five nozzles, which is referred to as a nozzle group B2, and so on.

  In FIG. 11, nozzle groups B1, B2,... Composed of these five nozzles are alternately shifted in the sub-scanning direction as shown in FIG.

  Specifically, the interval Lm in the main scanning direction between the nozzle groups is a positive integer N (the number of nozzles in each nozzle group, in this case, with respect to the minimum inter-nozzle distance Pm in the main scanning direction in this arrangement as before. 5), Lm = N × Pm.

  Further, the interval Ls between the nozzle groups in the sub-scanning direction is the minimum inter-nozzle distance Ps (substantially omitted) in the sub-scanning direction for the nozzle group B1 and the nozzle group B2, for example, by comparing the nozzles 51-11A and 51-13A. 2 times the size L2 of the pressure chamber 52 in the sub-scanning direction), Ls = 2 × Ps (= 2 × L2).

  The interval Ls in the sub-scanning direction for the nozzle group B2 and the next nozzle group B3 is just the minimum nozzle interval Ps in the sub-scanning direction. Hereinafter, this is repeated.

Further, in FIG. 7, nozzles arranged adjacent to or in the vicinity of each other in the sub-scanning direction, such as nozzles 51-11A and 51-12A, have a distance in the main scanning direction of the droplets discharged from each nozzle. It shall be set larger than the diameter.

  Here, for example, the diameter of the nozzle is assumed to be 30 [μm], and the diameter of the droplet is substantially the same. Specifically, when the maximum dot diameter of a droplet ejected from a nozzle onto a recording medium is Dmax, a positive value that satisfies Dmax ≦ N × Pm with respect to the minimum inter-nozzle distance Pm in the main scanning direction. By taking an integer N, the deviation of each nozzle block in the main scanning direction is set to N × Pm.

  Thus, if N is set and the nozzles are separated in the main scanning direction by a distance N × Pm, the droplets ejected from each nozzle are not only immediately after ejection but also after the recording medium is conveyed, It is possible to prevent image deterioration without overlapping permanently. As described above, the integer N is the number N of nozzle blocks.

  In FIG. 7, when setting the interval Ls between the nozzle blocks in the sub-scanning direction, the above is set to an integral multiple of the minimum nozzle distance Ps in the sub-scanning direction. Specifically, the integer M is the number M of nozzle rows arranged in the sub-scanning direction in the nozzle block.

  On the other hand, the interval Ls between the nozzle blocks adjacent in the sub-scanning direction may be set as follows. That is, in FIG. 7, after a droplet is ejected by the nozzle 51-11A of the nozzle block 1 and a part of the droplet penetrates into the recording paper 16, the droplet diameter on the surface of the recording paper 16 becomes small. The recording paper 16 can be transported and discharged from the nozzles 51-21A of the nozzle block 2 so as to overlap the droplets. As will be described in detail later, even if the liquid droplets are superimposed on the area where the liquid droplets have already penetrated into the recording paper 16 and the liquid droplets are ejected, the penetrated liquid droplets are fixed. This is because the droplets discharged from the liquid are not mixed and spread.

  That is, a part (peripheral) of the first droplets that have been ejected penetrates the recording paper 16 and remains on the surface of the recording paper 16 and the surface of the recording paper 16 that has been ejected afterwards. If the condition that the sum with the radius is smaller than the inter-dot pitch (the minimum inter-nozzle distance Pm in the main scanning direction) is satisfied, landing interference does not occur. Therefore, the interval Ls between the nozzle blocks in the sub-scanning direction is set as the time until the radius on the surface of the recording paper 16 of the first droplet deposited reaches a size satisfying the above condition after landing (the landing interference is reduced). It is also possible to set the distance so that the recording paper 16 is conveyed within a droplet ejection interval that is not generated), and to dispose the nozzle blocks apart in the sub-scanning direction by this distance.

  In this manner, the droplet ejection interval for preventing the droplet dots ejected by overlapping adjacently in the main scanning direction from interfering will be described below.

  The nozzles 51-11A of the nozzle block 1 and the nozzles 51-21A of the nozzle block 2 shown in FIG. 7 or 8 will be described as examples of nozzles that eject droplet dots adjacent in the main scanning direction. FIG. 12 shows the ink droplet 100 previously ejected by the nozzle 51-11A. The droplet diameter of the ink droplet 100 on the surface of the recording paper 16 is defined as D1a.

  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. 13 is a cross-sectional view taken along the line XIII-XIII in FIG. 12, and shows a state immediately after the ink droplet 100 has landed on the recording paper 16. FIG. 14 shows a state where a predetermined time less than the complete penetration time T has elapsed after the ink droplet 100 has landed on the recording paper 16, and the diameter of the ink droplet 100 on the surface of the recording paper 16 has become D1b. .

  A circle indicated by a broken line in FIG. 14 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 has landed on the recording paper 16. That is, the ink droplet 100 forms a dot 102 having a diameter D1a.

  FIG. 14 shows a state in which an ink droplet 110 having a diameter D2a is subsequently ejected by the nozzle 51-21A of the nozzle block 2. The distance in the main scanning direction between the nozzle 51-11A that has previously ejected the ink droplet 100 and the nozzle 51-21A is the minimum inter-nozzle distance Pm in the main scanning direction in this nozzle array. The center-to-center distance (dot pitch distance) Pt is the minimum nozzle distance Pm in the main scanning direction.

The diameter D1b after the time δT has elapsed since the ink droplet 100 previously ejected by the nozzle 51-11A landed on the recording paper 16, and the diameter D2a of the ink droplet 110 when landed on the recording paper 16. The relationship between the distance between the ink droplet 100 and the ink droplet 110 (corresponding to the pitch of dots formed from the ink droplet 100 and the ink droplet 110) Pt is expressed by the following equation (1).
Pt> (D1b / 2) + (D2a / 2) (1)
In the case of satisfying the above, the sum of the radii of the respective ink droplets 100 and 110 (respectively (D1b / 2) and (D2a / 2)) is smaller than the inter-dot pitch Pt. Since the ink droplet 100 and the ink droplet 110 are not mixed, the shapes of the dot 102 and the dot 112 (formed in the same position and in the same size as the ink droplet 110 in FIG. 14) are broken. Absent. Therefore, a desired dot shape can be obtained.

  The above formula (1) can also be expressed as the following formula (2).

D1b <2 × Pt−D2a (2)
That is, the time until the diameter D1a of the ink droplet 100 ejected from the nozzle 51-11 onto the recording paper 16 reaches the diameter D1b satisfying the equation (2) is defined as the droplet ejection interval for preventing landing interference. do it.

  Here, the condition that the dot 102 and the dot 112 overlap is Pt <(D1b / 2) + (D2a / 2), contrary to the equation (1). That is, the condition that 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 inter-dot pitch Pt.

  The dots 102 shown in FIG. 14 indicate that the area where the ink droplet 100 has not penetrated into the recording paper 16 (the area indicated as the ink droplet 100) and the penetration of the ink droplet 100 into the recording paper 16 have been completed. 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. 15 is a cross-sectional view showing cross sections of the ink droplet 100 and the ink droplet 110 taken along line XV-XV in FIG. 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 completed, and as shown in FIG. D2a dots 112 are formed.

  17 is a cross-sectional view showing a cross section of the dot 102 and the dot 112 along the line XVII-XVII in FIG.

  In this way, when two dots overlap, the next ink is ejected without waiting for the complete permeation time T when the permeation of the previously ejected ink droplet is completed (in the state of D1b> 0). Can do.

  That is, the distance Pt between the ink droplet 100 that has landed first and the ink droplet 110 that landed next, the diameter D2a when the ink droplet 110 landed, and the ink droplet 100 that satisfies the above equation (2) when the ink droplet 110 landed. The diameter D1b is obtained, and the permeation time δT is obtained from the obtained diameter D1b of the ink droplet 100 and the diameter D1a at the time of landing of the ink droplet 100. The droplet ejection timing of the ink droplet 100 ejected from the nozzle 51-11A and the ink droplet 110 ejected from the nozzle 51-21A is controlled with the penetration time δT thus determined as the droplet ejection interval.

  Further, the product of the time δT thus obtained and the conveyance speed V of the recording paper 16, δT × V, is set as the predetermined interval in the sub-scanning direction, and the nozzles 51-11A and 51- The nozzle block 1 and the nozzle block 2 may be arranged so that the distance in the sub-scanning direction is 21A.

  FIG. 18 is a block diagram showing a system (droplet ejection control unit) that performs such droplet ejection control. This droplet ejection control unit 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 ink, 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. 16), and the diameter D2a of the ink droplet (ink droplet 110 in FIG. 16) to be ejected later. From this, the diameter D1b of the ink droplet previously ejected (ink droplet 100 in FIG. 16) is obtained. 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.), timing control parameters in the main scanning direction, and the like are determined from the penetration time δT.

  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 drive signal generation unit 218 drives the nozzles 51-11A and 51-21A. 220 is generated.

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. This database may be provided inside the inkjet recording apparatus 10 or may be provided outside.

  As described above, the nozzle block is moved by the distance (calculated by V × δT based on the conveyance speed V of the recording paper 16) during the penetration time δT thus determined. By disposing the nozzles in the sub-scanning direction as shown in FIG. 7 or FIG. 10, the landing time intervals of the ink droplets that are overlapped with each other on the recording medium and ejected from different nozzles are lengthened. Bleeding can be prevented.

  In the above, a system has been described in which the droplets on the recording medium surface of the dots ejected onto the recording medium are fixed by penetration, but the droplets on the recording medium surface of the dots ejected onto the recording medium are dried or Even in a system that fixes by solidifying on the surface of the recording medium by curing, the droplet ejection interval can be controlled in the same manner as in the case of penetration.

  Also, the nozzles are arranged such that the distance in the sub-scanning direction between the nozzles adjacent to or in the vicinity of the main scanning direction is separated by a distance that allows the droplet dots to be fixed on the recording medium. Therefore, it is possible to reliably prevent landing interference and realize high-quality image recording.

Needless to say, a material that is liquid-resistant to alkaline ink is used for each member. Examples of the optimal resin material for the ink supply tank (not shown) 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.

  Although the liquid droplet ejection head and the image forming apparatus of the present invention have been described in detail above, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course.

  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. The length of the flow path is not particularly limited, but is preferably 1 mm or more and 10 m or less, and more preferably 5 mm.
It is preferably not less than 10 mm and not more than 10 m, particularly preferably not less than 10 mm and not more than 5 m.

  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.

  Representative examples of the reaction apparatus used in the present invention are shown in FIGS. Needless to say, the present invention is not limited to these examples.

  FIG. 20 (a) is an explanatory view of a reactor (1010) having a Y-shaped channel, and FIG. 20 (b) is a 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 or rectangular shape. 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. 21 (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. 21 (b) is a cross-sectional view taken along line IIa-IIa of the same device. FIG. 21C 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 manner as the apparatus of FIG. 20A, 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. The present apparatus having a cylindrical tube type flow path can take a larger contact interface between the two liquids than the apparatus shown in FIG. 20 (a), 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.

  22 (a) and FIG. 23 are modifications of the apparatus of FIG. 20 (a) and FIG. 21 (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. 20 (a) or FIG. 21 (a). Specifically, a uniform solution of an organic pigment is introduced into the inlet 1011 in FIG. 20A or the inlet 1021 in FIG. 19A, and the inlet 1012 in FIG. 20A or FIG. 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. 21 (a)) 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.

  Since 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, they have an outlet designed as shown in FIG. 22 (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 preferably within a range where the solvent does not solidify or vaporize, but is preferably -20 to 90 ° C, more preferably 0 to 50 ° C. Especially 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 component) 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, still more preferably 40 ° C to 120 ° C, and most preferably. Is 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, 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 two inlets of a Teflon (registered trademark) Y-shaped connector having an equivalent diameter of 500 μm using a connector, 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 liquid is sent out at a liquid feeding speed of 1 mL / h and the IIA liquid is sent out at a liquid feeding speed of 6 mL / h, the flow path 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, 0.5 mL of IB solution was added to 3.0 mL of the IIA solution in a beaker at room temperature while stirring with a stirrer to obtain a dispersion of 2,9-dimethylquinacridone. 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. Flow path width A: 100 μm, flow path width B: 100 μm, flow path width C: 100 μm, flow path length F: 12 cm, flow path depth H: Y-shaped as shown in FIG. In a reaction apparatus having a mold channel, two Teflon (registered trademark) tubes are connected to an inlet 1011 and an inlet 1012 using connectors, and syringes containing only IC solution and distilled water are connected to the ends. Set on the 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 the cylindrical flow path shown in FIG. 21 (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 2,9-dimethylquinacridone is dispersed. Since a liquid was obtained, it was collected from the outlet 1024. 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.). Flow path width A: 100 μm, flow path width B: 100 μm, flow path width C: 100 μm, flow path length F: 12 cm, flow path depth H: 40 μm glass Y-shaped flow shown in FIG. In the reaction apparatus having a channel, two Teflon (registered trademark) tubes were connected to the inlet 1011 and the inlet 1012 using connectors, and the ID liquid and the IIA liquid prepared in Example 1 were respectively added to the ends. 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. 21 (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 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 having a Y-shaped flow path described in FIG. 22 (a) and separable at the outlet, two Teflon (registered trademark) tubes are connected to the inlet 1031 and the inlet 1032 using connectors, Before that, syringes containing the IB solution prepared in Example 3 and the IIA solution prepared in Example 1 were 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 flow channel as shown in FIG. 23 having a flow channel diameter N: 100 μm, a flow channel diameter P: 300 μm, a flow channel diameter O: 100 μm, a flow 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 9 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 path shown in FIG. 21A having a flow path diameter D: 100 μm, a flow path diameter E: 400 μm, a flow path length G: 20 cm, the portion of the flow path 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 showing an outline of an inkjet recording apparatus as an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a plan view of a main part around a printing unit of the ink jet recording apparatus of FIG. FIG. 6 is a plan perspective view illustrating another example of the structure of the print head. It is an enlarged view showing a pressure chamber unit constituting a print head. It is sectional drawing which follows the VV line of FIG. FIG. 2 is a system configuration diagram of the ink jet recording apparatus of FIG. 1. It is a principal part top view which shows nozzle arrangement in the print head of this embodiment. It is a top view which expands and shows a part of nozzle arrangement | positioning of FIG. (A), (b) is explanatory drawing which shows the relationship between nozzle arrangement | positioning and a dot position. It is a principal part top view which shows other nozzle arrangement | positioning in the print head of this embodiment. It is a top view which shows the other division method of a nozzle block in the nozzle arrangement | positioning of FIG. It is explanatory drawing of droplet ejection control of the inkjet recording device of this embodiment. It is sectional drawing which follows the XIII-XIII line | wire in FIG. It is a top view for demonstrating the principal part of droplet ejection control. It is sectional drawing which follows the XV-XV line | wire in FIG. It is a top view explaining the result of droplet ejection control. It is sectional drawing which follows the XVII-XVII line in FIG. It is a block diagram of a droplet ejection control unit of the ink jet recording apparatus of the present embodiment. It is a principal part top view which shows the nozzle arranged in the conventional matrix form. It is explanatory drawing of the reaction apparatus which has a Y-shaped channel on one side. It is sectional drawing of the II line | wire of Fig.20 (a). It is explanatory drawing of the reaction apparatus which has a cylindrical tube type flow path provided with the flow path penetrated to one side. It is sectional drawing of the IIa-IIa line | wire of Fig.21 (a). It is sectional drawing of the IIb-IIb line | wire of Fig.21 (a). It is explanatory drawing of the reactor which has a Y-shaped channel on both sides. It is sectional drawing of the III-III line | wire of Fig.22 (a). It is explanatory drawing of the reaction apparatus which has a cylindrical tube type flow path provided with the flow path penetrated on both sides.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 12 ... Printing part, 14 ... Ink storage / loading part, 16 ... Recording paper, 18 ... Paper feeding part, 20 ... Decal processing part, 22 ... Adsorption belt conveyance part, 24 ... Print detection part, 26 DESCRIPTION OF REFERENCE SYMBOLS: Paper discharge unit, 28 ... Cutter, 30 ... Heating drum, 31, 32 ... Roller, 33 ... Belt, 34 ... Adsorption chamber, 35 ... Fan, 36 ... Belt cleaning unit, 40 ... Heating fan, 42 ... Post-drying unit, 44 ... heating / pressurizing unit, 45 ... pressure roller, 48 ... cutter, 50 ... print head, 51 ... nozzle, 52 ... pressure chamber, 53 ... ink supply port, 54 ... pressure chamber unit, 55 ... ink common flow path 56 ... Vibration plate 58 ... Actuator 1010, 1020, 1030, 1040 ... Reactor body, 1011, 1012, 1021, 1022, 1031, 1032, 1041, 1042 ... Inlet, 1013, 1033 ... flow path, 1013a, 1013b, 1023a, 1023b, 1033a, 1033b, 1043a, 1043b ... introduction flow path, 1013c, 1023c, 1033c, 1043c ... reaction flow path, 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 (13)

An organic pigment solution dissolved in an alkaline or acidic aqueous medium is circulated in the flow path as a laminar flow on the recording medium, and the hydrogen ion index (pH) of the solution is changed in the laminar flow process. A recording head for ejecting droplets containing organic pigment fine particles,
Two-dimensionally in the main scanning direction orthogonal to the conveying direction in which the recording medium is conveyed relative to the droplet discharge head and in the sub-scanning direction that is the conveying direction, and from the nozzles onto the recording medium. The nozzles are arranged so that at least some of the ejected dots overlap in the main scanning direction,
For the first nozzle, the second nozzle, and the third nozzle that are adjacent to the first nozzle in the sub-scanning direction on the recording medium, the dots that are adjacent to each other in the main scanning direction
The distance in the sub-scanning direction between the first nozzle and the second nozzle is at least an integral multiple of 2 or more of the distance in the sub-scanning direction of the first nozzle and the third nozzle. And disposing the first nozzle and the second nozzle apart in the sub-scanning direction,
The distance in the main scanning direction between the first nozzle and the third nozzle is at least a maximum dot diameter formed by droplets ejected from the first nozzle and the third nozzle onto the recording medium. A liquid droplet ejection head, wherein the first nozzle and the third nozzle are arranged apart from each other in the main scanning direction so as to have the above distance.   The distance in the main scanning direction between the first nozzle and the third nozzle is at least an integer multiple of 2 or more of the distance in the main scanning direction between the first nozzle and the second nozzle. The droplet discharge head according to claim 1, wherein the droplet discharge head is provided. An organic pigment solution dissolved in an alkaline or acidic aqueous medium is circulated in the flow path as a laminar flow on the recording medium, and the hydrogen ion index (pH) of the solution is changed in the laminar flow process. A recording head for ejecting droplets containing organic pigment fine particles,
Two-dimensionally in the main scanning direction orthogonal to the conveying direction in which the recording medium is conveyed relative to the droplet discharge head and in the sub-scanning direction that is the conveying direction, and from the nozzles onto the recording medium. The nozzles are arranged so that at least some of the ejected droplet dots overlap in the main scanning direction,
Pm is the minimum distance between nozzles in the main scanning direction, which is the minimum distance in the main scanning direction between nozzles in the droplet discharge head,
A plurality of nozzle rows arranged in a row in the main scanning direction are shifted in the main scanning direction and arranged adjacent to each other in the sub scanning direction, and a nozzle row shifted by a predetermined distance in the main scanning direction with respect to an arbitrary nozzle row The nozzle blocks adjacent to each other in the sub-scanning direction among the plurality of nozzle blocks formed so as to always exist are shifted by a predetermined interval in the sub-scanning direction and between the minimum nozzles in the main scanning direction in the main scanning direction. A droplet discharge head characterized by being arranged by being shifted by a distance Pm.   The predetermined distance for shifting the nozzle row in the main scanning direction is set to be N × Pm using the minimum inter-nozzle distance Pm in the main scanning direction and the number N of the nozzle blocks. 4. A droplet discharge head according to item 3.   The predetermined interval in the sub-scanning direction between the nozzle blocks is defined as the sub-scanning direction minimum inter-nozzle distance Ps that is the distance between nozzles adjacent to each other in the sub-scanning direction in the nozzle array and the nozzle rows constituting each nozzle block. The droplet discharge head according to claim 3, wherein the droplet discharge head is set to be M × Ps by using the number M. The predetermined in the sub-scanning direction between the first nozzle block and the second nozzle block each having a first nozzle and a second nozzle for ejecting droplet dots overlapping in the main scanning direction on the recording medium. At least the first dots landed from the first nozzle are fixed on the recording medium, the droplet diameter on the surface of the recording medium is reduced, and the landing of the first dots The conveyance speed at which the recording medium is relatively conveyed is set so that the time until the second dots that land from the second nozzle later do not come into contact with the droplets on the surface of the recording medium is reached. The liquid droplet ejection head according to claim 3, wherein the liquid droplet ejection head is set according to at least the type of the recording medium.   When the maximum dot diameter of droplets ejected from the arbitrary nozzles constituting the nozzle array onto the recording medium is Dmax, Dmax ≦ N × Pm with respect to the minimum inter-nozzle distance Pm in the main scanning direction. The droplet discharge head according to claim 3, wherein the number N of the nozzle blocks is set as described above. An organic pigment solution dissolved in an alkaline or acidic aqueous medium is circulated in the flow path as a laminar flow on the recording medium, and the hydrogen ion index (pH) of the solution is changed in the laminar flow process. A recording head for ejecting droplets containing organic pigment fine particles,
Two-dimensionally in the main scanning direction orthogonal to the conveying direction in which the recording medium is conveyed relative to the droplet discharge head and in the sub-scanning direction that is the conveying direction, and from the nozzles onto the recording medium. The nozzles are arranged so that at least some of the ejected dots overlap in the main scanning direction,
The distance in the sub-scanning direction between the first nozzle and the second nozzle that deposits the first and second dots that are deposited adjacently or overlapped in the main scanning direction on the recording medium is at least the first The first dot is landed and fixed on the recording medium, the droplet diameter on the surface of the recording medium is reduced, and the recording medium surface of the second dot that is ejected after the landing of the first dot Set so that the recording medium is relatively transported over the time until it reaches a size that does not contact the droplets above,
The distance in the main scanning direction between the first nozzle and the third nozzle adjacent in the sub-scanning direction is the maximum formed by ejecting droplets from at least the first nozzle and the third nozzle onto the recording medium. A droplet discharge head, wherein the first nozzle and the third nozzle are arranged so as to have a distance equal to or greater than a dot diameter.   The liquid droplet ejection head according to claim 1, wherein the organic pigment fine particles are generated from a solution of an organic pigment containing at least one dispersant.   The droplet discharge head according to claim 1, wherein the organic pigment fine particles have a mode diameter of 1 μm or less. 11. The droplet discharge according to claim 1, wherein the organic pigment fine particle is a quinacridone pigment represented by the general formula (I), wherein the solution of the organic pigment is alkaline. head.

(Wherein 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 an alkyl group having 1 to 10 carbon atoms), 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 droplet discharge head according to any one of 1 to 11.   An image forming apparatus comprising the droplet discharge head according to claim 1.

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