JP2005111880A - Ink jet head and ink jet printing apparatus having the head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the amount of mist generated due to the smaller droplets of an ejected liquid in an ink jet recording head and the advancement of recording speed. In order to solve this mist problem, an ink jet head capable of sucking and collecting mist without adding a member is realized.
A member is added by arranging a mist suction hole so as to surround a row of inkjet discharge holes in an inkjet discharge hole plate or a signal electrode film, or both the inkjet discharge hole plate and the signal electrode film. Instead, the ink mist is sucked and collected from the mist suction hole.
[Selection] Figure 1

Description

  The present invention relates to an ink jet printing apparatus that prints characters and images on a recording medium such as paper on a demand by an electric signal as a small droplet of a liquid such as ink, and an ink jet print head used therefor. is there.

  As an inkjet printing apparatus, a printing apparatus that is widely used regardless of consumer or industrial use, such as a general inkjet printer, or a printing apparatus used for a facsimile apparatus, a copying apparatus, a register, or the like using an inkjet system. It is a device. Ink jet prints tend to improve print image quality as the size of the ink jet print particles decreases. For this reason, as of 1995, the volume of the ink jet ejection droplets was about 80 pL (picoliter), but as of 2002, it has been reduced to about 2 pL. For this reason, the size of one dot of the print at the stage where the inkjet discharge droplets land (attach) on the paper surface is dramatically improved from the past of about 0.1 mm to the present of about 50 μm, The delicate painting is realized. However, when the size of a single droplet is reduced, the number of droplets required for printing increases to about 10 to 100 times depending on the image to be printed. When a photographic print image is added to this, the number of colors is increased to about 1000 times including the increase in the number of colors.

  By the way, there is no problem as long as all of these inkjet discharge droplets adhere to a print medium such as paper and become a print image, but in reality, some of the particles become minute droplets and float in the air. Phenomenon that does not adhere to the paper surface of a print medium such as paper occurs. In particular, the smaller the size of the ink jet ejected droplets, the relatively the proportion of minute droplets increases. Therefore, it is a fact that the existence probability of micro floating droplets called mist has increased dramatically between the era of conventional inkjet discharge droplets of about 50 pL to 80 pL and the present day of 2 pL to 5 pL. is there. By the way, it is only necessary that these particles float, but in reality, a phenomenon occurs that the particles adhere to everywhere inside the printer at some point. When the amount of adhesion increases gradually, various concerns occur that the inside of the printer is contaminated or the end of the paper to be printed becomes dirty and adheres. These series of concerns are described in detail in JP-A No. 2002-307725.

Techniques for absorbing floating fine ink particles (mist) generated during ink jet printing have been studied in various ways. For example, Japanese Patent Laid-Open No. 5-124187 discloses a lively technique in which the mist is forcibly attached to the paper surface by electrostatic force to save the trouble of absorbing and collecting the mist. Japanese Patent Application Laid-Open No. 7-25007 discloses a technique for collecting mist by providing a mist recovery fan and a mist suction member on the carriage of an inkjet head. Japanese Patent Application Laid-Open No. 10-16231 discloses a technique in which a porous mist absorber is disposed in the vicinity of an inkjet discharge hole of an inkjet head to absorb and suck mist. Further, although JP 2000-79696 A is not a technique for collecting mist, an ink jet head is formed by forming a hole in the ink jet discharge hole surface of the ink jet head and sending and sucking humidified air near the ink jet discharge hole. The technology to prevent the sticking and dew condensation is disclosed. In Japanese Patent Laid-Open No. 2002-307725, as the most orthodox technique, an air blowing hole and a suction hole are provided at various locations of the printer body to form an air flow, and the mist is conveyed to the flow to provide the mist. A technique for absorbing and collecting selenium is disclosed. As described above, various mist collection techniques are disclosed.
Japanese Patent Laid-Open No. 5-124187 JP 7-25007 A Japanese Patent Laid-Open No. 10-16231 JP 2000-79696 A JP 2002-307725 A

  The problem of the technique described in Japanese Patent Application Laid-Open No. 5-124187 is that, in order to absorb mist by static electricity, it is necessary to generate a high voltage between the inkjet head and the paper surface as clearly shown in the same publication. is there. For this reason, a high-voltage generator is required, and because of the high voltage, it is necessary to secure the edge distance, limit the material, carefully select and respond to various electrical safety standards in order to prevent electric shock from the outside. It is. Therefore, there is a problem that these countermeasures require man-hours and costs and can be applied only to a relatively expensive printer apparatus, and this technique is not widely used in general. In addition, since the inkjet head itself is loaded with such a high voltage (potential difference), the inkjet discharge element itself has a problem that it cannot be produced at low cost by general semiconductor technology, which is disadvantageous economically. There is a problem that. Furthermore, there is a problem that the electric lines of force are concentrated on the paper surface even though it is instantaneous, and the problem that the mist and the ink jet discharge droplets themselves are selectively accumulated in the portion where the electric lines of force are selectively concentrated. There is also a drawback that the image becomes rough, and there is a concern that high-definition image printing such as photographic tone cannot be performed.

  Further, the problem of the technique described in Japanese Patent Application Laid-Open No. 7-25007 is that a mist collecting device is arranged at a position farther from the ejection hole of the inkjet head. The problem of adhering occurs. Of particular concern is the concern that mist accumulates in the vicinity of the ink jet ejection hole surface in the middle of its path, forming droplets and dripping onto the paper to be printed. At this time, the printed medium (such as paper) at this time becomes a defective product.

  Further, the problem of the technique described in Japanese Patent Application Laid-Open No. 10-16231 is a problem that this technique can be adopted only for an ink jet print head having a specific shape. Currently, ink jet print heads that are widely used generally have at least three to four colors of ink jet discharge holes, such as yellow, magenta, cyan, and black, arranged in parallel on the surface of the ink jet discharge holes. It is. However, what is proposed in this publication is only applicable to an inkjet head (usually an edge shooter type) in which only one row of inkjet discharge holes can be arranged. Further, there are problems that the suction pipe has to be arranged up to the vicinity of the ink jet discharge holes and that a new porous mist absorber needs to be arranged as a separate component. A special large-sized inkjet print head of 4 inches or 8 inches in length, which may be used for a one-row arrangement, an inkjet having small parallel multiple rows of inkjet discharge holes that are currently widely available It cannot be applied to the head.

  Further, the technique described in Japanese Patent Laid-Open No. 2000-79696 relates to an edge shooter type ink jet head having a single row of ink jet discharge holes, as in the technique of Japanese Patent Laid-Open No. 10-16231. Thus, there is no specific description such as whether a large number of air suction holes are formed on the ink jet discharge hole surface. The ink jet head is fixed to the ink jet printer, and is not configured to be detachable as the ink jet head. Since it is not originally a viewpoint of mist absorption, since the point of focus is different, the problem is also separate.

  Similarly, in the technique described in Japanese Patent Application Laid-Open No. 2002-307725, a mist absorption hole is disposed in a portion far from the inkjet discharge head, which is a mist generation place, and therefore, in the mist distribution path. There is a concern similar to the technical problem described in Japanese Patent Laid-Open No. 7-25007, in which mist adheres. However, it is technically clear that the technique of the above publication has the effect of reducing the generated mist. The only difference is that there is a different balance between the economic burden and the effectiveness of installing it.

  As described above, it has been found that there are various problems in the prior art.

  Furthermore, in these prior arts, there are practical problems that are not mentioned and have not been solved. In the ink jet printing, liquid ink is fixed after being attached to paper or the like. In this fixed time zone (only about 2 to 30 seconds), liquid (mainly water) is absorbed and evaporated. In order to solve such problems as the fixing speed is slow and the paper surface is sticky or the characters bleed out, the ink is fixed by using another fixing auxiliary liquid or by neutralization reaction with alkali / acid. This is a problem in the case of using the method to make it. Since these methods use two or more types of reactive inks, these mists are floating somewhere and fixed when they meet each other. That is, after these mists are ejected from the ink jet discharge holes, there is a need to individually collect the mists without mixing. If these inks are generated in the ink jet discharge holes, the ink jet discharge holes may be clogged, and ink cannot be discharged from the ink jet discharge holes. That is. This means that no means or technique for solving this problem has been mentioned in the prior art.

  As a result of intensive studies, the present inventor has made it possible to find the following solutions. The basic principle is that the economic burden is reduced as much as possible, and the ink jet head structure is realized without increasing its volume and without increasing new parts. The means is a groove path communicating with a dead space of an ink jet discharge hole plate or a member to which a TAB signal electrode film is bonded in an ink jet head having a large number of parallel ink jet discharge holes that are widely used at present. Is formed, and the mist suction path is formed by covering with the inkjet discharge hole plate or the TAB signal electrode film, and further, the mist suction hole is inkjet discharged into the inkjet discharge hole plate or the TAB signal electrode film. The mist suction path is disposed so as to surround the hole array, and the other end of the mist suction path is joined to one end of the mist suction means. In this way, it is possible to individually surround each ink jet discharge hole array and suck mist without adding a new member and without increasing the volume of the ink jet head. By such means, it becomes possible to collect the mist directly in the vicinity of the ink jet discharge hole before floating to various places.

  In addition, in the above-mentioned new problem, when the inks cause mutual fixation reaction, after absorbing the mist, it is possible to collect the mist absorption path separately in another path so as not to be clogged by mixed fixation. Thus, new problems can be solved.

  As described above, according to the present invention, a configuration capable of collecting mist without newly providing a suction member on the inkjet head is possible. Therefore, an excellent function of enabling mist suction without increasing the occupied volume or occupied plane ratio of the inkjet head is exhibited. In addition, an excellent function is provided in which different types of ink can be sucked and collected before the mutual ink mists are mixed in the vicinity of the mist generation source.

  Further, the ink jet head 100 and an ink jet head carriage 95 on which the head can be detachably mounted are in contact with each other and continuously connected to a mist suction pipe disposed on the carriage via a rubber packing. Therefore, the convenience of being able to be installed in a state where mist suction is possible with one touch without performing complicated suction pipe connection processing is also exhibited.

  Furthermore, when the ink can not be absorbed only by the ink absorber called the pre-discharge in the operation stage with the pre-discharge, it is possible to increase the mist collection and collection efficiency by sucking the mist from the mist suction hole. .

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  A first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view of an inkjet head 100 showing a specific example according to an example of the present invention. The ink jet head 100 is basically composed of an ink jet head casing 4 and an ink jet ejection element 10 as is generally known. Needless to say, various components are added to make the inkjet head 100 function. In this specific example, as shown in FIG. 1, the mist absorbing holes 1 are arranged on the surface where the inkjet discharge holes 11 are arranged so as to surround the inkjet discharge hole array 11. The mist absorption hole 1 is formed in the TAB electrode film 2. Further, the ink jet discharge holes 11 are simultaneously formed in the TAB electrode film 2 by laser processing or the like. An electrode terminal pad 31 and a mist suction joint hole 9 are disposed on the other end of the TAB electrode film 2. In addition, the inkjet discharge element 10 is disposed and bonded on the inkjet discharge element holding body 6, and then bonded and held with the inkjet head housing 4. Of course, it goes without saying that ink and an ink storage part for storing the ink are arranged inside the inkjet discharge casing 4 and an ink flow path through which the ink flows to the inkjet discharge element 10 is configured. Needless to say, the TAB electrode film 2 is held by being bonded to the inkjet head housing 4, the inkjet ejection element holder 6, and the inkjet ejection element 10 with an adhesive or the like. Under the TAB electrode film 2, a mist suction communication groove 7 (shown by a broken line) is arranged. The TAB electrode film 2 is a kind of flexible electric wire. Generally, an electric signal line is arranged on a film such as polyimide or polyamide by a method such as plating or vapor deposition, and a material of the same quality is further formed thereon. It is a film electric signal line in a flexible film state in which the electrode terminal pad 31 and the connection terminal electrode thereof are provided as a point of electrical connection with the outside.

  In FIG. 2, the inkjet head 100 with the TAB electrode film 2 removed is listed as the TAB electrode film 2. The ink jet ejection element 10 has three ink supply ports 50 and a mist suction communication groove 71 formed on one silicon semiconductor chip. Several tens to 612 ink heating portions (commonly referred to as heaters) are arranged in the longitudinal direction on both sides of the three ink supply ports 50, but they are too small to be drawn. It is said. The ink supply port 50 penetrates a silicon semiconductor chip having a thickness of 0.625 mm by a sandblasting method or an etching removal method. Therefore, the ink is communicated with the ink flow path disposed on the back surface, so that the ink is sequentially supplied. The mist suction communication groove 71 on the ink jet discharge element is formed as the communication groove 71 having a depth of about 0.2 mm by a sandblast method, a diamond grinding removal method, an etching removal method, or the like. In addition, an electrode connection terminal 21 for receiving an electrical signal from the TAB electrode film 2 is disposed in the inkjet discharge element 10. Generally, the electrode connection terminal 21 is made of gold having a thickness of about 5 μm, and a similar structure is also arranged on the terminal side relatively connected to the terminal 21 arranged on the TAB electrode film 2. . When the TAB electrode film 2 and the inkjet discharge element 10 are relatively aligned and ultrasonic pressure bonding is performed, the electrodes are bonded together. In some cases, fine tin, zinc-gold alloy particles, or the like are used for re-joining. The inkjet discharge element 10 is fixed on the inkjet discharge element holder 6 with an adhesive (generally an epoxy adhesive) or the like. Further, a mist suction groove 7 is formed by providing a gap between the inkjet discharge element 10 and the ink discharge element holding body 6. By disposing the mist suction groove 7 so as to communicate with the mist suction communication groove 7 disposed on the side surface of the ink jet head casing 4, mist generated around the ink jet discharge hole array 11 is removed from the ink jet head casing 4. Suction to the side position is possible. Then, the mist can be sucked out and collected outside through the mist suction joint hole 9 arranged on the TAB electrode film 9. In this example, the TAB electrode film 2 is also used as an inkjet discharge hole plate. The aspect will be described in a little more detail. FIG. 3 is a view of the TAB electrode film 2 as seen from the back side (in the direction of the inkjet discharge element 10 in FIG. 2). The TAB electrode film 2 has a mist suction hole 1 and an ink jet discharge hole 11, and a common ink flow path 13 and an individual ink flow path 12 are formed on the back side by laser processing as shown in FIG. ing. Further, since the connection electrode terminal facing the electrode connection terminal 21 on the inkjet discharge element 10 which should be originally shown is omitted, it is not shown. Needless to say, an adhesive layer for adhering to the inkjet discharge element holder 6 and the inkjet discharge element 10 is formed on the upper surface of the TAB electrode film 2 shown in FIG. The mist absorption mechanism functions by detachably mounting the inkjet head 100 configured as described above on the inkjet head carriage 95 disposed on the inkjet printer shown in FIG. By mounting the inkjet head 100 on the carriage 95, the mist suction joint packing 73 in FIG. 6 is continuously joined to the mist suction hole 9 of the inkjet head 100. Thus, the mist generated in the vicinity of the ink jet discharge hole 11 can be directly collected and removed outside by sucking the mist from the mist suction pipe 91 with suction means such as a suction pump. Even when the inkjet head 100 is mounted on the inkjet head carriage 95 and moved to the left and right on the transport shaft 96 for printing, the mist generated around the inkjet ejection holes 11 does not float inside the inkjet printer, and is immediately The ink is sucked from the suction hole 1 and absorbed and accumulated in the ink mist suction and collection part.

  In this example, the ink discharge hole plate and the TAB electrode plate 2 are integrated. However, these plates or films may be separated into two parts.

  Of course, it is needless to say that the mist suction communication grooves 7 are separately disposed in a plurality of mist suction grooves, so that various mists of different colors or types can be avoided and sucked and removed.

  Another embodiment will be described with reference to FIGS. FIG. 4 shows a case where the inkjet discharge element 10 is manufactured by dividing it into three pieces, and the mist suction hole 1 is arranged on the mist suction communication groove 7 formed in the inkjet discharge element holding body 6. belongs to. Although it can be seen that there is no big difference from the case of FIG. 1, the case shown in FIG. 4 is superior in terms of production efficiency, and it can be easily applied to the inkjet discharge element 10 having a length of about 1 inch. is there. That is, there are 256 or 612 ink jet discharge holes 11 per one color (one line of the discharge hole) on the ink jet discharge element 10, so that there are at least 768 or more discharge holes for three colors or four colors. There will be. When dust or the like enters due to some mistakes or malfunctions in the production process, if even one bottle is clogged with a discharge hole, it becomes a defective product and the production efficiency decreases. In the case of the inkjet discharge element 10 of the example shown in FIG. 1 integrated with three colors, such a probability is at least three times higher than the case of combining the inkjet discharge elements 10 for each color shown in FIG. . Therefore, the case shown in FIG. 4 is superior in terms of production (good product) efficiency. An exploded schematic perspective view of the example of FIG. 4 is shown in FIG. The structure of the inkjet discharge element 10 used here is described in Japanese Patent Application Laid-Open No. 11-99649 and Japanese Patent Application Laid-Open No. 10-119277. In FIG. 5, three inkjet discharge elements 10 are bonded onto the inkjet discharge element holder 6 with an adhesive or the like. A continuous mist suction communication groove 7 is disposed in the inkjet discharge element holder 6. In general, the inkjet discharge element holding body 6 is often made of an alumina sintered body. Therefore, an alumina powder is put into a mold formed like this shape and is formed by powder press molding. After manufacturing, it is manufactured by firing. Or when manufacturing by injection molding of resin, such a shape is created in a metal mold | die and the mist suction | inhalation communicating groove 7 is formed by injection molding. The mist suction communication groove 7 is disposed so as to be continuous with the mist suction communication groove 7 formed on the side wall surface of the inkjet head housing 4. If the TAB electrode film 2 in FIG. 5 is covered and thermally bonded using an adhesive or the like on the configuration of this embodiment, the inkjet head 100 shown in FIG. 4 is manufactured. In the case of FIGS. 4 and 5, since the ink jet discharge holes 11, the ink common flow path 13, the individual ink flow path 12 and the like are already formed in the ink jet discharge element 10, the TAB electrode film in this portion is unnecessary. . For this purpose, an inkjet discharge opening 20 is provided as shown in FIG. At this stage, there is a slight gap or a slightly weak portion in the portion between the inkjet discharge element 10 and the TAB electrode film 2, so that the sealing agent 15 is poured in order to prevent such a portion. 4 is completed as an inkjet head 100 as shown in FIG. The sealant 15 does not have a shape as shown in FIG. 5 and is an irregularly shaped emulsified object, but for the sake of explanation, it has a shape as shown in the figure. This emulsified object is sequentially cured by ultraviolet rays, heat, time, etc., and finally solidifies in a shape as shown in FIGS. With such a configuration, even if a large number of mists are generated from the inkjet discharge holes 11, the mists are sucked from the mist suction holes 1 arranged around the discharge hole row 11 and pass through the communication grooves 7. Furthermore, it is configured to be sucked and collected by the mist suction pipe 91 on the carriage 95 shown in FIG. 6 via the mist suction hole 9. Since the mist suction joint packing 73 disposed on the carriage 95 is made of soft rubber, the mist suction joint packing 73 on the inkjet head 100 is continuously in good communication with the mist suction joint packing 73. In particular, the packing 73 is more reliable when super flexible silicone rubber manufactured by Toray Silicone Co., Ltd. is used. This super-flexible rubber is preferably about 10 to 40 degrees as measured by an Asker C rubber hardness meter, and has excellent flexibility and resilience. Therefore, it is not necessary to perform connection processing with a complicated suction pipe 91. Excellent convenience that can be easily connected and communicated even with a single touch.

  Of course, if each of the mist suction communication grooves 71 arranged in the inkjet discharge element holding body 6 is formed as a separate and independent path, the number of suction pipes 91 and mist suction holes 9 increases, but each color or each ink type, Alternatively, the mist is sucked separately for each discharge hole row. In this way, even ink that is reactively fixed can be recovered while preventing the mist from mixing and reacting.

  The example will be described with reference to FIG. In FIG. 7, two series of mist suction communication grooves 7 </ b> A and 7 </ b> B are arranged in the inkjet discharge element holder 6. Naturally, the mist suction hole 1 is formed at a position corresponding to the mist suction communication grooves 7A and 7B. The size of the mist suction hole 1 is preferably about 0.1 mmφ to 1 mmφ, although it depends on the position and the type of size of the ink jet droplet to be ejected. The number and distribution thereof can be arbitrarily varied so as to exhibit the function. Inkjet ejection elements 10A and 10B are arranged. The inkjet discharge element 10A is an inkjet discharge element that discharges an anionic ink, and yellow is generally used as the ink. The ink jet ejection element 10B is an ink jet ejection element that ejects cationic ink. Generally, cyan or magenta is often used as the ink. This is because when printing yellow, which has little effect on image quality when printing colors and characters, is printed slightly under the cyan, magenta, or black ink, cyan, magenta, The speed of fixing is increased by utilizing an anion / cation reaction with black ink to solidify the ink dye. In such a case, since cyan and magenta may be mixed, they are sucked and collected using one mist suction communication groove 7B. However, since it is not preferable to mix yellow with cyan or magenta, yellow is sucked and collected using the mist suction communication groove 7A of another system. Naturally, the mist suction communication groove formed on the side surface of the inkjet head housing 4 is also arranged in two systems, and the mist suction joint hole 9 and the mist suction pipe 91 are also arranged in two systems. In this way, it goes without saying that if the number of ink mists that must be collected separately increases, a suction collection system of a corresponding system is required. In addition to the anion / cation reaction as described above, a colorless, transparent or white print adjuvant is printed first, and then the ink of the next several colors is quickly solidified by oxidation-reduction reaction, neutralization reaction, or other methods. This is also effective for fixing the adhesive.

  As described above, the mist suction communication groove 7 and the mist suction hole 7 can absorb and collect mist in the vicinity of the generation source corresponding to the inkjet head 100 having the inkjet discharge hole array 11 of various forms.

  In particular, the effect is exhibited when the ink jet head is habituated and discharged at the pre-ink jet printing stage, ie, preliminary discharge at a home position or another specified position. At this time, since a large amount of discharge processing is performed, a large amount of mist is generated. In many cases, this cannot be absorbed only by an ink absorber called a preliminary discharge receiver. In such a case, it is possible to increase mist collection and collection efficiency by sucking mist from the mist suction hole.

1 is a schematic perspective external view of an inkjet head for explaining a first embodiment of the present invention. FIG. 2 is a schematic perspective external view of the ink jet head shown in FIG. 1 disassembled. FIG. 3 is a schematic external view for enlarged explanation of members used in FIGS. 1 and 2. It is a general | schematic perspective external view of the inkjet head for demonstrating the 2nd Example of this invention. FIG. 5 is a schematic perspective external view of the ink jet head shown in FIG. 4 disassembled. 1 is a schematic external view for explaining a printing apparatus equipped with an ink jet head of the present invention. FIG. 6 is a schematic external perspective view of an ink jet head for explaining a third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mist suction hole 2 TAB electrode film 4 Inkjet head housing 6 Inkjet ejection element holder 7 Mist suction communication groove 9 Mist suction joint hole 10 Inkjet ejection element 11 Inkjet ejection hole 22 Signal electrode film 91 Mist suction pipe 95 Inkjet head carriage 100 Inkjet head

Claims (6)

Inkjet ejection hole plate having inkjet ejection holes for ejecting ink, inkjet ejection element for imparting ejection energy to the ink, holder for the inkjet ejection element, and inkjet head housing carrying the holder And an inkjet head having a signal electrode film for transmitting an ejection signal to the inkjet ejection element,
A mist suction hole is disposed in the inkjet discharge hole plate, the signal electrode film, or both the inkjet discharge hole plate and the signal electrode film so as to surround a row of inkjet discharge holes. head.   A continuous mist suction groove is disposed in the inkjet discharge element, or the holding body, or both the inkjet discharge element and the holding body so as to surround the row of the inkjet discharge holes, and the mist suction groove is disposed on the mist suction groove. A communication path for mist suction is formed by bonding the inkjet discharge hole plate, the signal electrode film, or both the inkjet discharge hole plate and the signal electrode film so as to cover each other. The inkjet head according to claim 1.   In the communication path, a communication groove that communicates with the mist suction groove is also extended in the inkjet head housing portion, and the signal electrode film covers the communication groove so as to cover the mist suction groove. The inkjet head according to claim 2, wherein a communication path is formed.   A communication joint hole to the outside is disposed at the end of the communication path disposed in the inkjet head housing, and one end of the communication path is a mist suction hole and the other end is a communication joint hole. The inkjet head according to claim 2 or 3.   The mist suction hole, the mist suction groove, the communication groove, and the communication joint hole are arranged for each ink color or for each row of inkjet discharge holes, and a plurality of sets are formed. Item 5. The inkjet head according to Item 4.   6. An ink jet printing apparatus comprising: the ink jet head according to claim 4; a carriage on which the ink jet head is mounted; and a mist suction pipe disposed on the carriage and connected to the communication joint hole.

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