JP2008006646A - Liquid discharge head and liquid discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preferable liquid discharge head and liquid discharge apparatus which are improved in an air bubble removal performance in a common liquid chamber in a full line type head. <P>SOLUTION: In a full line type print head 100 constituted of a plurality of head chips 50 arranged in the width direction of recording paper, an assembly member 120 is provided between the a common liquid chamber member 102 and the head chips 50. In the assembly member 120, a beam 122 corresponding to a joining part of head chips 50 adjacent to each other is formed, and a communication hole 128 is formed in the beam 122. When ink in the common liquid chamber 55 is circulated in a predetermined direction, turbulence of an ink flow is not generated since the ink passes through the communication hole 128, and a stagnation point of the ink flow is thereby prevented from being generated in the vicinity of the beam 122. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus, and more particularly to a structure of a liquid discharge head that discharges droplets of a size from a nozzle.

  In recent years, inkjet recording apparatuses (inkjet printers) have become widespread as recording apparatuses that print and record images taken by digital still cameras. An ink jet recording apparatus includes a plurality of nozzles in a head, and ink droplets are ejected from the nozzles onto a recording medium to record a desired image on the recording medium. In such an ink jet recording apparatus, a line type head corresponding to the width direction of the recording medium is used, and the head and the recording medium are moved in a predetermined moving direction to perform image printing on the entire surface of the recording medium. The head is scanned in the width direction of the recording medium to perform printing in the width direction of the recording medium, and after the recording medium is moved by a predetermined distance in a direction substantially orthogonal to the scanning direction of the head, printing in the width direction of the recording medium is performed. Compared to the repetitive serial method, the printing speed is increased and the productivity is improved.

  Here, FIGS. 28A to 28C show the print head 1 according to the prior art. The print head 1 shown in FIGS. 28A to 28C is a full line type head configured by arranging two head chips 50 in the width direction of the recording medium. FIG. 28 (a) is a perspective view of the print head 1, and FIGS. 28 (b) and 28 (c) are a sectional view taken along line bb in FIG. 28 (a) and c in FIG. 28 (a), respectively. It is sectional drawing which follows the -c line.

  28A to 28C, in the back surface flow path structure in which the integrated common liquid chamber 55 common to each head chip 50 is provided on the upper surface (back surface) side of the head chip 50, each head chip 50 is provided. The assembly member 2 is used at the joint between the liquid chamber 55 and the common liquid chamber 55. The assembly member 2 includes a beam portion 3 provided corresponding to the joint portion 104 of the adjacent head chip, and seals a gap generated in the joint portion 104 between the two head chips 50 by the beam portion 3. A structure that does not cause ink leakage is realized.

  Many full-line heads have a structure including a common liquid chamber integrated with a plurality of nozzles (pressure chambers), and for some reason bubbles are generated in the ink stored in the common liquid chamber. If the bubbles are mixed into the pressure chamber or the nozzle, there is a risk of abnormal discharge. Therefore, various techniques have been proposed for eliminating or dissolving bubbles in the common liquid chamber to prevent bubbles from entering the nozzle and the pressure chamber.

The invention described in Patent Document 1 discloses a full-line type liquid ejecting apparatus in which a plurality of element substrates (corresponding to heads) are arranged in the nozzle arrangement direction so that the entire print width is the same as the width of the recording medium. ing. In the liquid ejection device described in Patent Document 1, the upper ceiling surface of the common liquid chamber that supplies liquid from the back side of the element substrate is formed with an inclination with respect to the horizontal, and the uppermost portion of the upper ceiling surface or A bubble channel is connected to the vicinity. The bubbles contained in the liquid in the common liquid chamber are collected at the top along the upper ceiling surface, and are discharged from the dummy discharge port to the atmosphere via the bubble flow path.
JP 2002-144576 A

  However, the assembly member 2 shown in FIGS. 28 (a) to 28 (c) requires a rigidity that does not deform when the common liquid chamber 55 and the head chip 50 are joined. (Length in the vertical direction) is required. In the line-type head 1 having the structure shown in FIGS. 28A to 28C, when the ink is circulated aiming at the bubble discharge in the common liquid chamber 55 (white in FIGS. 28A and 28B). In the vicinity of the beam portion 3 of the assembly member 2, for example, there is a stagnation point 4 (upstream side of the ink flow) in a portion surrounded by a circle shown in FIG. ), A stagnation point 5 (on the downstream side of the ink flow) is formed, and the bubbles are caught at the stagnation point 4 and the stagnation point 5, so that it can be said that it is difficult to discharge the bubbles. Even if the circulation flow rate is increased for the purpose of eliminating the stagnation points 4 and 5 and the stagnation points 4 and 5 in FIG. 28B are eliminated, the flow rate of the ink in the common liquid chamber 55 at the stagnation point remains. The stagnation points 4 and 5 are not eliminated. Therefore, the presence of the beam portion 3 makes it difficult to discharge bubbles in the common liquid chamber 55 by circulation.

  In addition, although it is possible to suck ink from the nozzle (shown by reference numeral 51 in FIGS. 3 and 4) to discharge bubbles in the common liquid chamber 55, the sucked ink becomes waste liquid and wasteful ink consumption occurs. End up.

  As shown in FIGS. 29 (a) to (c), the print head 6 having a structure in which the assembly member 2 in FIGS. 28 (a) to (c) is omitted is common to reference numerals 4 and 5 in FIG. 28 (b). Although the stagnation point in the liquid chamber 55 is eliminated, since the head chips 50 must be brought into direct contact with each other, high precision is required for the alignment of the head chips 50 during the manufacture and assembly of the head chips 50. The If a predetermined accuracy is not ensured in the manufacture and assembly of the head chip 50, the gap 106 is generated in the joint portion 104 between the head chips 50, and ink leakage occurs.

  Further, when a temperature change occurs inside the head chip 50 or around the head chip 50, warping occurs when the head chips 50 are in contact with each other, and a gap 106 is generated by this warping (or The gap 106 is enlarged, and ink leakage occurs.

  As shown in FIGS. 28A to 28C, it is possible to relatively reduce the stagnation point 4 and the stagnation point 5 by reducing the height h of the beam portion 3, but the assembly member 2 When the height h is small, when the head chip 50 is bonded (adhered) to the assembly member 2, the bonding position becomes unstable due to insufficient strength (rigidity) of the assembly member 2, and handling of the assembly member 2 becomes difficult. .

  Although it is conceivable to eliminate the stagnation point 4 and the stagnation point 5 by chamfering the corner portion of the beam portion 3 to smooth the corner portion, the width w of the beam portion 3 (see FIG. 28A). ) Needs to be relatively large. Since the nozzle cannot be arranged below the beam portion 3, the nozzle density of the entire head 1 cannot be increased. By arranging the head chips 50 in a staggered manner, the nozzle density can be increased even if the width w of the beam portion 3 is increased, but the width L in the short direction (paper feed direction) of the head 1 (FIG. 28 (a ))) Becomes larger.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a preferable liquid discharge head and liquid discharge apparatus that have improved bubble removal performance in a common liquid chamber in a full line type head.

  In order to achieve the above object, a liquid discharge head according to the present invention is a long liquid discharge head having a structure in which a plurality of head chips each having a nozzle for discharging a liquid are connected, and corresponds to the head chip. A plurality of openings are formed, and an assembly member that joins the plurality of head chips in a predetermined arrangement by bonding to a surface opposite to the liquid discharge direction of the head chips, and supplies the liquid to the plurality of head chips And a common liquid chamber member that is bonded to a side surface opposite to the surface to which the head chip of the assembly member is bonded, and the assembly member has a beam portion that separates adjacent openings. A flow path communicating with an opening adjacent to each other is formed.

  According to the present invention, it is possible to eliminate the stagnation point of the liquid flow in the common liquid chamber that occurs in the opening of the assembly member (that is, the partitioned region in the vicinity of the head chip of the common liquid chamber). Air bubbles are prevented from entering the head chip. Further, by eliminating the stagnation point, the liquid flow is secured, and the dissolution of bubbles in the liquid by the liquid flow is promoted.

  The head chips are arranged in one row along the longitudinal direction of the liquid ejection head, or in a staggered manner in two rows along the longitudinal direction of the liquid ejection head.

  The direction in which the beam portion is formed (that is, the longitudinal direction of the beam portion) is substantially orthogonal to the longitudinal direction of the liquid discharge head (that is, the longitudinal direction of the common liquid chamber), for example, when the head chip is square or rectangular. When the head chip is a parallelogram, the beam forming direction is an oblique direction that is not orthogonal to the longitudinal direction of the liquid ejection head (a direction parallel to the side that intersects the longitudinal direction of the liquid ejection head of the parallelogram). Become.

  It is preferable that the flow path formed in the beam portion is formed in a direction substantially parallel to the main ink flow direction of the common liquid chamber. Of course, the flow path formation direction may be an angle θ (−90 degrees <θ <90 degrees) with the ink flow direction.

  In addition, the flow path has the same shape (the shape of the surface substantially perpendicular to the flow path formation direction) over the entire area in the formation direction, and has a straight shape with no bending over the entire area in the formation direction. Holes are preferred.

  The head chip includes a plurality of nozzles for discharging liquid, a plurality of pressure chambers (individual liquid chambers) communicating with the plurality of nozzles, a pressure generating element for pressurizing the liquid in the pressure chambers, and the common liquid chamber. There is a mode in which a supply port (supply throttle) serving as a liquid flow path to the pressure chamber is provided, and the supply port is provided in a non-joining region with the assembly member on the joint surface with the assembly member of the head chip.

  In addition, it is possible to form a full-line head by connecting the head chips over a length corresponding to the width of the recording medium (a direction substantially orthogonal to the moving direction in which the liquid ejection head and the recording medium are relatively moved). is there.

  The recording medium is a medium that receives the liquid ejected by the liquid ejection head. Various media can be used regardless of material or shape, such as continuous sheets, cut sheets, sealing sheets, resin sheets such as OHP sheets, films, cloths, and the like. Including.

  A second aspect of the invention relates to an aspect of the liquid discharge head according to the first aspect of the invention, wherein the flow path is a through hole that penetrates the beam portion.

  According to invention of Claim 2, the rigidity of a beam part and the whole assembly member is ensured by making the flow path which penetrates a beam part into a through-hole.

A third aspect of the present invention relates to an aspect of the liquid ejection head according to the first or second aspect, wherein a plurality of the flow paths are provided in the beam portion, and the plurality of flow paths are connected to the beam portion and the beam. In the projection plane projected on the joint surface with the head chip, the distance P between the centers of the adjacent flow paths is expressed by the following formula P, where the maximum length in the arrangement direction of the two adjacent flow paths is L ₁ and L ₂ , respectively. > _(L 1/2) +, characterized in that distributed a plurality of flow paths so as to satisfy _(L 2/2).

  According to the third aspect of the present invention, in the aspect including a plurality of flow paths, each flow path is formed so as not to overlap the other flow paths in the height direction of the beam section. The rigidity of the assembly member) is leveled, and the assembly member is prevented from bending unevenly as a whole.

  In an aspect in which a plurality of flow paths are dispersedly arranged in the beam portion, there is an aspect in which two rows of flow paths are staggered. For example, two rows of flow passages in which the flow passages having the same planar shape and substantially the same size (diameter) are arranged at equal intervals in the beam portion forming direction are provided in the height direction of the beam portions, and the flow passages in the same flow passage row The maximum length in the arrangement direction is less than the length between the opposing outer edge portions of the adjacent flow paths, and the other flow path is located in the area between the adjacent flow paths in one flow path row (the non-flow path forming area). A row of channels is arranged. Note that the uppermost flow channel may have a groove shape.

  A fourth aspect of the present invention relates to an aspect of the liquid ejection head according to the first, second, or third aspect, wherein a cross-sectional surface shape of the flow path in a plane orthogonal to a formation direction of the flow path is the beam portion. The ratio of the maximum length in the height direction of the beam portion to the maximum length in the direction in which the beam is formed exceeds 1.

  According to the invention of claim 4, the flow path is orthogonal to the flow path formation direction represented by the ratio of the maximum length in the height direction of the beam section to the maximum length in the formation direction of the beam section. Since the flow path is formed so that the aspect ratio of the cross-sectional shape of the flow path on the surface to be exceeded exceeds 1, the beam portion (assembly member) is less likely to bend than the flow path having the aspect ratio of 1 or less. .

  A fifth aspect of the present invention relates to one aspect of the liquid ejection head according to any one of the first to fourth aspects, wherein one end portion of the flow path is a lower end in the height direction of the beam portion. When the liquid stored in the common liquid chamber is circulated in the circulation direction along the longitudinal direction of the liquid discharge head, the flow path is disposed near the lower end portion in the height direction of the beam portion. The liquid stored in the common liquid chamber is circulated so that the side on which the end is formed is the downstream side in the circulation direction.

  According to the fifth aspect of the present invention, the end portion of the flow path (opening in the case of the through hole) is provided in the portion where the liquid flow is likely to stagnate (that is, the stagnation point) in the common liquid chamber, and the stagnation point is directly provided. Introducing liquid flow to prevent stagnation of the liquid flow.

  A sixth aspect of the present invention relates to one aspect of the liquid ejection head according to any one of the first to fifth aspects, wherein the assembly member has other heights in the periphery and in the vicinity of the periphery. It has a structure higher than the height of the part.

  According to the invention described in claim 6, since the assembly member has a structure in which the height of the peripheral portion is higher than that of other portions, the deformation of the assembly member can be suppressed as a whole.

  The vicinity of both ends of the beam portion may be included in the vicinity of the peripheral portion. The aspect in which the height in the vicinity of both ends of the beam portion is higher than the other portions is, for example, an aspect in which the height is gradually (continuously) increased from the central portion side to the both end portions side of the beam portion. is there. The peripheral portion of the assembly member may be a joint region with the common liquid chamber member.

  A seventh aspect of the present invention relates to an aspect of the liquid discharge head according to any one of the first to sixth aspects, wherein the beam portion is substantially parallel to a forming direction of the nozzle of the head chip. A dummy nozzle formed in a direction, the dummy nozzle having one end communicating with the flow path and the other end communicating with the atmosphere in a non-bonding region with the head chip on the bonding surface with the head chip. It has the structure which communicates.

  According to the seventh aspect of the present invention, the gas in the common liquid chamber (in the beam passage) can be discharged into the atmosphere via the dummy nozzle. The invention described in claim 7 is preferable because the bubbles staying in the communication hole can be efficiently eliminated when the flow path is the communication hole.

  In order to discharge the gas accumulated in the flow path to the atmosphere via the dummy nozzle, the suction may be performed from the outside of the dummy nozzle using a suction means, or a pressure variable means for varying the pressure in the common liquid chamber may be provided. It may be used to pressurize the liquid in the common liquid chamber.

  According to an eighth aspect of the present invention, there is provided the liquid ejection head according to any one of the first to sixth aspects, wherein the assembly member has a protrusion that can be inserted between adjacent head chips. The protrusion includes a dummy nozzle formed in a direction substantially parallel to the nozzle forming direction of the head chip. The dummy nozzle has one end communicating with the flow path and the other end. It has a structure in which the portion reaches the tip end portion of the protruding portion and communicates with the atmosphere at the other end portion.

  According to the eighth aspect of the invention, the gas accumulated in the common liquid chamber, particularly in the flow path, can be discharged to the atmosphere. Further, by using the protrusion as a pin (positioning member) for positioning the head chip and the assembly member, it is easy to align them.

  A ninth aspect of the invention relates to an aspect of the liquid discharge head according to the seventh or eighth aspect, wherein the dummy nozzle has a length that intersects the flow path and penetrates the beam portion. And

  According to the ninth aspect of the invention, the ease of manufacturing is expected to be improved by forming the dummy nozzle as a through hole.

  In order to achieve the above object, a liquid discharge head according to the invention of claim 10 is a long liquid discharge head having a structure in which a plurality of head chips each having a nozzle for discharging a liquid are connected. An assembly member formed with a plurality of openings corresponding to the head chips, joined to a surface opposite to the liquid ejection direction of the head chips, and joining the plurality of head chips in a predetermined arrangement; A common liquid chamber that supplies liquid to the head chip, and a common liquid chamber member that is bonded to a side surface opposite to the surface to which the head chip of the assembly member is bonded, and the assembly members are adjacent to each other. A porous member is used for the beam portion that separates the opening.

  According to the invention of claim 10, since the porous member is used for the beam portion of the assembly member provided between the head chip and the common liquid chamber, the liquid in the common liquid chamber can flow inside the beam portion. And no stagnation point of liquid flow occurs in the common liquid chamber. Further, since the liquid flow does not stagnate, it is possible to obtain an effect of dissolving bubbles in the liquid by the liquid flow.

  In addition, since capillary force acts on the porous member, the liquid stored in the common liquid chamber does not leak from the portion of the beam portion that contacts the atmosphere (joining portion of the adjacent head chips), and the head chip does not leak. The meniscus of the nozzle provided is maintained.

  An eleventh aspect of the invention relates to an aspect of the liquid discharge head according to the tenth aspect of the invention, wherein the beam portion includes an air shielding member on a joint surface with the head chip.

  According to the eleventh aspect of the present invention, since the beam portion is provided with the airtight member on the joint surface with the head chip, the common liquid chamber is blocked from the atmosphere even when the porous member is used for the beam portion. Degassed liquid can be used.

   According to a twelfth aspect of the present invention, a liquid ejection apparatus includes the liquid ejection head according to any one of the first to eleventh aspects.

  The liquid ejecting apparatus includes an image forming apparatus (inkjet recording apparatus) that ejects ink onto a recording medium to form a desired image.

  According to the present invention, it is possible to eliminate the stagnation point of the liquid flow in the common liquid chamber that occurs in the opening of the assembly member (that is, the partitioned region in the vicinity of the head chip of the common liquid chamber). Air bubbles are prevented from entering the head chip. Further, by eliminating the stagnation point, the liquid flow is secured, and the dissolution of bubbles in the liquid by the liquid flow is promoted.

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

[Overall configuration of inkjet recording apparatus]
FIG. 1 is an overall configuration diagram of an ink jet recording apparatus (liquid ejection apparatus) according to an embodiment of the present invention. As shown in the figure, the inkjet recording apparatus 10 includes a print unit 12 having a plurality of print heads 12K, 12C, 12M, and 12Y provided for each ink color, and each print head 12K, 12C, 12M, An ink storage / loading unit 14 for storing ink to be supplied to 12Y, a paper supply unit 18 for supplying recording paper 16 (recording medium), a decurling unit 20 for removing curl of the recording paper 16, and the printing A suction belt conveyance unit 22 that is arranged to face a nozzle surface (ink ejection surface, not shown in FIG. 1) of the unit 12 and conveys the recording paper 16 while maintaining the flatness of the recording paper 16; A print detection unit 24 that reads the print result of the paper, and a paper discharge unit 26 that discharges printed recording paper (printed matter) to the outside.

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

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

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

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

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

  The belt 33 has a width that is 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.

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

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

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

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

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

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

  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 sub-scanning direction is performed once. An image can be recorded on the entire surface of the recording paper 16 only by performing it (that is, in one sub-scan). Thereby, it is possible to perform high-speed printing as compared with a shuttle type head in which the print head reciprocates in the main scanning direction, and productivity can be improved.

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

  As shown in FIG. 1, the ink storage / loading unit 14 has tanks that store inks of colors corresponding to the print heads 12K, 12C, 12M, and 12Y, and each tank is connected via a conduit (not shown). The print heads 12K, 12C, 12M, and 12Y communicate with each other. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means, 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 for imaging the droplet ejection result of the print unit 12, and functions as a means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor.

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

  The print detection unit 24 reads the test pattern printed by the print heads 12K, 12C, 12M, and 12Y for each color, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like. In addition, the print detection unit 24 includes a light source (not shown) that irradiates light to the ejected dots.

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

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  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 sorting means (not shown) that switches the paper discharge path so as to select the print product of the main image and the print product of the test print and send them to the discharge units 26A and 26B. Yes. 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 in FIG. 1, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders. Reference numeral 26B denotes a test print discharge unit.

[Description of print head structure]
Next, the structure of the print head will be described. Since the structures of the print heads 12K, 12C, 12M, and 12Y provided for the respective ink colors are common, the print heads are represented by the reference numeral 100 in the following.

  The print head 100 according to the present invention is a full line type head having a printable width corresponding to the length in the width direction of the recording paper 16 as shown in FIG. 2, and as shown in FIG. The print head 100 has a structure in which short head chips 50 having a printable width less than the length in the width direction of the recording paper 16 are arranged and connected in the width direction of the recording paper 16 (head chip arrangement direction). is doing.

  FIG. 3B is a plan perspective view showing a structural example of the head chip 50 constituting the print head 100. As shown in FIG. 3B, the head chip 50 includes a plurality of ink chamber units 53 including nozzles 51 from which ink is ejected and pressure chambers 52 corresponding to the nozzles 51 in the width direction of the recording paper 16. It has a structure arranged in a line along the scanning direction.

  The pressure chamber 52 provided corresponding to each nozzle 51 has a substantially square planar shape, and the nozzle 51 and the supply port 54 are provided at both corners on the diagonal line. Further, each pressure chamber 52 communicates with a common liquid chamber (not shown in FIG. 3, indicated by reference numeral 55 in FIG. 4) via a supply port.

  FIG. 4 is a cross-sectional view (a cross-sectional view taken along line IV-IV in FIG. 3A) showing a three-dimensional configuration of the ink chamber unit (print head 100). A pressure generating element (piezoelectric element) 58 having an individual electrode 57 is joined to the pressure plate 56 constituting the top surface of the pressure chamber 52, and the pressure plate 56 is also used as a common electrode of the pressure generating element 58. ing. By applying a driving voltage to the individual electrode 57, the pressure generating element 58 is flexibly deformed, the pressure chamber 52 is deformed, and ink is ejected from the nozzle 51 to the outside. When the pressurization of the ink in the pressure chamber 52 by the pressure generating element 58 is completed after the ink droplets are ejected, new ink is supplied from the common liquid chamber 55 through the supply port 54 to the pressure chamber 52.

  The print head 100 shown in this example has a back surface flow path structure for supplying ink from a common liquid chamber 55 provided on the back side of the pressure chamber 52 into the pressure chamber 52. That is, the print head 100 has a structure in which the pressure chamber 52 communicates with the common liquid chamber 55 provided on the opposite side of the pressure chamber 52 from the pressure plate 56 through the supply port 54 provided in the pressure plate 56. is doing. In such a back surface flow path structure, the flow path length (discharge side) between the nozzle 51 and the pressure chamber 52 compared to other structures (for example, a structure including the common liquid chamber 55 on the nozzle 51 side of the pressure chamber 52). The flow path length of the flow path) and the flow path length of the supply side restrictor (supply port 54) (flow path length of the supply side flow path) can be shortened, and the ink chamber units 53 can be arranged at high density. It becomes possible. Accordingly, it can be said that the head in which a large number of nozzles 51 are arranged at high density can realize a high discharge cycle. In particular, this structure is advantageous when high-viscosity ink is discharged at a high discharge frequency of about several tens kHz to a hundred kHz.

  When the back surface flow path structure shown in FIG. 4 is used, the pressure generating element 58 is provided on the common liquid chamber 55 side of the pressure plate 56 (inside the common liquid chamber 55). A cover member 59 that covers the pressure generating element 58 is provided so that the ink and the pressure generating element 58 do not come into contact with each other. Further, in a mode in which a wiring (not shown) for transmitting a drive signal applied to the pressure generating element 58 is provided on the common liquid chamber 55 side of the pressure plate 56, the wiring is subjected to a predetermined insulation process.

  A mode in which the above-described wiring is provided on the upper surface side of the common liquid chamber 55 (the side surface opposite to the pressure plate 56 of the common liquid chamber 55) is also preferable. That is, a member that forms the ceiling surface of the common liquid chamber 55 is formed of a wiring board on which a wiring pattern is formed. The common liquid chamber 55 is drawn from the individual electrode 57 to the pressure generating element arrangement surface of the pressure plate 56 and rises from the electrode. The individual electrode 57 and the wiring pattern of the wiring board are brought into conduction through a wiring member formed so as to penetrate the wiring board. This wiring member is formed so as to be lined up in the common liquid chamber 55, and also functions as a support member that supports the wiring member that forms the ceiling surface of the common liquid chamber 55.

  In the present embodiment, a method is employed in which ink is pressurized by deformation of a pressure generating element 58 typified by a piezo element (piezoelectric element). In implementing the present invention, an actuator other than the piezoelectric element can be applied to the pressure generating element 58. Alternatively, a thermal method may be applied in which ink inside the pressure chamber 52 is generated by a heater provided in the pressure chamber 52 to generate bubbles and the ink droplets in the pressure chamber 52 are heated by the bubbles. Good.

[Description of ink supply system]
Next, the ink supply system of the inkjet recording apparatus 10 will be described with reference to FIG. FIG. 5 is a schematic diagram showing the configuration of the ink supply system in the inkjet recording apparatus 10.

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

  As shown in FIG. 5, a filter 62 is provided between the ink supply tank 60 and the print head 100 in order to remove foreign substances and bubbles. The filter mesh size is preferably equal to or smaller than the nozzle diameter (generally about 20 μm).

  A configuration in which a sub tank (not shown in FIG. 5 and indicated by reference numeral 122 in FIG. 8) is provided in the vicinity of the print head 100 or integrally with the print head 100 is also preferable. The sub-tank has a function of improving a damper effect and refill that prevents fluctuations in the internal pressure of the print head 100.

  The mode in which the internal pressure is controlled by the sub tank includes a mode in which the internal pressure in the pressure chamber 52 is controlled by the difference in the ink water level between the sub tank opened to the atmosphere and the pressure chamber 52 in the head chip 50, or is connected to a sealed sub tank. There is a mode in which the internal pressures of the sub tank and the pressure chamber are controlled by a pump, and any mode may be applied.

  Although not shown in FIG. 5, the inkjet recording apparatus 10 includes a circulation unit (for example, a pump) that circulates the ink in the common liquid chamber 55. That is, a pump provided outside the print head 100 is connected to an ink circulation port (not shown in FIG. 5 and indicated by reference numerals 103A and 103B in FIG. 7A) of the print head 100 (common liquid chamber 55). The ink in the common liquid chamber 55 can be circulated by operating the pump. In the line type print head, it is preferable that the main ink flow be generated in a direction substantially parallel to the longitudinal direction.

[Description of head maintenance]
As shown in FIG. 5, the inkjet recording apparatus 10 is provided with a cap 64 as a means for preventing the nozzle 51 from drying or preventing an increase in the ink viscosity in the vicinity of the nozzle 51, and a nozzle forming surface on which the nozzle 51 is formed. A blade 66 is provided as a means for performing cleaning (wiping).

  The maintenance unit including the cap 64 can be moved relative to the print head 100 by a moving mechanism (not shown), and is moved from a predetermined retracted position to a position below the print head 100 as necessary.

  The cap 64 shown in FIG. 5 has a size that can cover the entire nozzle formation surface of the print head 100. The cap 64 is displaced up and down relatively with respect to the print head 100 by an elevator mechanism (not shown). The cap 64 is raised to a predetermined raised position when the power is turned off or during printing standby, and is brought into close contact with the print head 100 (the nozzle formation surface of the head chip 50), thereby covering the nozzle formation surface with the cap 64.

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

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

  Further, when air bubbles are mixed into the ink in the print head 100 (in the pressure chamber 52), the ink cannot be ejected from the nozzle even if the pressure generating element 58 is operated. In such a case, the cap 64 is applied to the print head 100, the ink in the pressure chamber 52 (ink mixed with bubbles) is removed by suction with the suction pump 67, and the sucked and removed ink is sent to the collection tank 68. . In this suction operation, the deteriorated ink with increased viscosity (solidified) is sucked out when the ink is initially loaded into the head or when the ink is used after being stopped for a long time. Since the suction operation is performed on the entire ink in the pressure chamber 52, the amount of ink consumption increases. Therefore, it is preferable to perform preliminary ejection when the increase in ink viscosity is small.

  Although illustration is omitted, it is also preferable to divide the inside of the cap 64 in correspondence with each head chip 50 and form each of the head chips 50 so that suction can be executed.

  The blade 66 functions as a wiping means that moves while being in contact with the nozzle forming surface to remove dirt on the nozzle forming surface, and a material such as hard rubber is preferably used. That is, the blade 66 has a predetermined strength (rigidity) and a predetermined elasticity, and the surface thereof has a predetermined water repellency that repels ink droplets and deaerated liquid. The blade 66 is formed of a member capable of wiping and removing ink adhering to the nozzle formation surface (ink that has solidified and adhered to the nozzle formation surface), paper dust, and other foreign matters.

  Although not shown in FIG. 5, the head maintenance mechanism (head maintenance means) of the inkjet recording apparatus 10 is configured to move the blade 66 in the vertical direction so as to contact / not contact the nozzle formation surface (non-contact). A blade up / down mechanism (not shown) for switching and a cleaning means for removing foreign matter adhering to the blade 66 are provided.

[Explanation of control system]
Next, a control system of the ink jet recording apparatus 10 shown in this example will be described. FIG. 6 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10. The inkjet recording apparatus 10 includes a communication interface 70, a system controller 72, an image memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 86. As the communication interface 70, a serial interface such as USB (Universal Serial Bus), IEEE 1394, Ethernet (registered trademark), a 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 motor driver 76 and the motor 88 in FIG. 6 include a plurality of motor drivers and motors, respectively. That is, the system controller 72 controls a plurality of motors via a plurality of motor drivers.

 As an example of a plurality of motors, there are a motor for rotating the rollers 31 and 32 in FIG. 1, a motor for an up-and-down mechanism for moving up and down the blade shown in FIG.

  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 heater 89 shown in FIG. 6 includes heaters such as the heater used in the post-drying unit 42 in FIG. 1 and the temperature adjusting heater of each head chip 50.

  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 control unit 80, and the ejection amount and ejection timing of the ink droplets of each head chip 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 actuator of each color print head 100 (each head chip 50) 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 program storage unit 90 stores a control program for the inkjet recording apparatus 10, and the system controller 72 appropriately reads out various control programs stored in the program storage unit 90 and executes the control program.

  The print detection unit 24 is a block including a line sensor, reads an image printed on the recording paper 16, performs predetermined signal processing, etc., and detects a print status (e.g., whether ejection has occurred, variation in droplet ejection, etc.) The detection result is provided to the print control unit.

  The print control unit 80 performs various corrections for the print head 100 (head chip 50) based on information obtained from the print detection unit 24 as necessary.

[First Embodiment]
Next, a first embodiment according to the present invention will be described.

  7A to 7C are exploded perspective views of the print head 100 according to the first embodiment of the present invention (the reference numerals are omitted from FIGS. 7A to 7C). 7A shows the common liquid chamber member 102 that becomes the common liquid chamber 55, and FIG. 7B shows the common liquid chamber member 102 and the common liquid chamber member 102 when the common liquid chamber member 102 and the head chip 50 are joined. The assembly member 120 provided between the head chip 50 is shown. FIG. 7C shows a state in which the head chips 50 constituting the print head 100 are arranged in a predetermined head chip arrangement direction.

  In the common liquid chamber member 102 shown in FIG. 7A, ink supplied to the plurality of head chips 50 is stored, and is common to the head chips 50 constituting the print head 100 and is an integrated common liquid chamber. 55. Further, the common liquid chamber member 102 includes ink circulation ports 103A and 103B at substantially central portions at both ends in the longitudinal direction.

  Although not shown in FIG. 7A, an adhesive is applied to the joint portion of the common liquid chamber member 102 with the assembly member 120. This adhesive also functions as a sealing member that seals the periphery of the common liquid chamber 55 to prevent ink leakage. Further, the assembly member 120 has a rigidity enough to crush the adhesive 130 that functions as a sealing member.

  FIG. 7B is a perspective view of the assembly member 120. The assembly member 120 includes a frame portion 121 having a substantially rectangular shape (similar to the planar shape of the common liquid chamber member) corresponding to the outer periphery of the common liquid chamber member 102 (a joint portion of the common liquid chamber member 102 with the assembly member 120). , And a beam portion formed in the short direction of the frame portion 121. That is, the frame part 121 has two side parts 121A and 121B along the longitudinal direction (the arrangement direction of the head chips 50), and is short at both ends in the longitudinal direction so as to connect the side parts 121A and 121B in the longitudinal direction. Sides 123A and 123B along the hand direction are provided.

  Further, the beam portion 122 moves the plurality of head chips 50 (see FIG. 7C) along the longitudinal direction of the print head 100 (not shown in FIG. 7) (in this example, a direction substantially orthogonal to the paper feed direction). Are formed at corresponding positions between adjacent head chips 50 when arranged in a row, and function as a member that fills a gap formed between adjacent head chips 50.

  That is, one of the wide surfaces of the assembly member 120 serves as a joint surface of the common liquid chamber member 102, and the other surface (a surface opposite to the joint surface of the common liquid chamber member 102) serves as a joint surface of the head chip 50. Become.

  The opening 126 surrounded by the two side parts 121A and 121B in the longitudinal direction of the assembly member 120 and the side part 123A (side part 123B) in the short direction of the beam part 122 or the assembly member 120 is provided for each head chip. 50, and an area obtained by removing the area of the joint portion between the assembly member 120 and the head chip from the area of the head chip 50.

  That is, the assembly member 120 has a ladder-like shape constituted by the side portions 121A and 121B in the longitudinal direction (the arrangement direction of the head chips 50), the beam portion 122, and the side portions 123A and 123B in the short direction. The structure has a plurality of openings 126 corresponding to the number of chips 50.

  Further, as shown in FIG. 7B, the beam portion 122 is provided with a communication hole 128 (flow path) that communicates two openings 126 separated by the beam portion 122. The communication hole 128 passes through the beam portion 122 in the thickness direction (the short direction of the beam portion 122 and the longitudinal direction of the print head 100), and allows ink to flow between the two openings 126 separated by the beam portion 122. Is formed.

  That is, the opening 126 serving as an individual liquid chamber corresponding to each head chip 50 is communicated by a communication hole 128 formed in the beam portion 122, and the ink accommodated in each head chip 50 is communicated by the communication hole. It can flow to the adjacent liquid chamber (opening 126) through 128.

  In FIG. 7B, the communication hole 128 is illustrated as a hole-shaped flow path. However, instead of the communication hole 128 (or in combination with the communication hole 128), the communication hole 128 side of the communication hole 128 ( The groove shape in which the upper side in FIG.

  The formation direction of the communication hole 128 shown in FIG. 7B is preferably substantially parallel to the short direction of the beam portion 122. Of course, the communication hole 128 may be formed in an oblique direction that is not orthogonal to the transverse direction of the beam portion 122. It is preferable that the communication hole 128 is formed in a direction parallel to the main ink flow direction in the common liquid chamber 55.

  FIG. 7C shows a plurality of head chips 50 arranged in the head chip arrangement direction. Although FIG. 7C illustrates two head chips, the print head 100 (see FIG. 3) may be configured using three or more head chips. When the print head 100 is formed using three or more head chips 50, the opening 126 shown in FIG. 7B is provided corresponding to the number of head chips 50. In other words, the assembly member 120 is formed with a number of beam portions 122 obtained by subtracting 1 from the number of head chips 50.

  An adhesive 130 for bonding to the assembly member 120 shown in FIG. 7B is applied to the periphery of the four sides of the head chip 50. A region where the adhesive 130 is applied becomes a joint portion with the assembly member 120. The adhesive 130 may be applied to the joint surface of the assembly member 120 with the head chip 50.

  Although FIG. 7C shows the head chip 50 having a substantially square planar shape, the planar shape of the head chip 50 is not limited to a square, and an aspect such as a rectangle or a parallelogram is also possible. A beam portion 122 of the assembly member 120 shown in FIG. 7B is formed in accordance with the planar shape of the head chip 50. For example, when the planar shape of the head chip 50 is a parallelogram, the beam 122 is formed in an oblique direction that is not orthogonal to the side 121A and the side 121B along the longitudinal direction of the assembly member 120 (the head chip 50 , A direction parallel to two sides intersecting with the arrangement direction of the head chips 50.

  FIG. 8A shows a cross-sectional view along the line VIIIa-VIIIa in FIG. FIG. 8B shows a cross-sectional view taken along the line VIIIb-VIIIb in FIG.

  As shown in FIG. 8A, the adhesive 130 that joins the beam portion 122 and the head chip 50 also functions as a sealing member that prevents ink leakage from the joint portion 104 of the adjacent head chip. Therefore, it is preferable to use a material excellent in ink resistance.

  Further, as shown in FIG. 8B, when the assembly member 120 is insufficient in rigidity, reference numeral 120A indicated by a broken line is applied by pressurization when the assembly member 120, the common liquid chamber member 102, and the head chip 50 are joined. Thus, the assembly member 120 is warped. Therefore, the height of the assembly member 120 (the rigidity of the assembly member 120 so that the assembly member 120 does not warp due to pressurization during joining). The vertical length (h) is defined. It is preferable that the height h of the assembly member is in the range of 1.0 mm to 1.5 mm.

  FIG. 9 is a perspective view showing a part of the assembly member 120 when the print head 100 is configured using three or more head chips 50 (see FIG. 7C).

  As shown in FIG. 9, the plurality of beam portions 122 provided in the assembly member 120 are formed with communication holes 128 having the same shape and the same size at the same position, so that the stagnation point of the ink flow is near the beam portion 122. (See FIG. 28) can be prevented, and when the ink in the common liquid chamber 55 (see FIG. 8B) is circulated, the ink flow in the common liquid chamber 55 is maintained uniformly.

  Thus, when the ink flow in the vicinity of the beam portion 122 is ensured by forming the communication hole 128 in the beam portion 122, the height h of the assembly member 120 (beam portion 122) is increased to increase the assembly member. The overall rigidity of 120 can be increased.

  Here, when the dimension example of each part which comprises the assembly member 120 is given, the thickness w of the beam part 122 is about 0.5 mm-1.0 mm, the thickness of the side parts 121A and 121B of a longitudinal direction, and a transversal direction. The thickness of the sides 123A and 123B (not shown) is also about 0.5 mm to 1.0 mm.

  7 (b) and FIG. 9 show an elliptical communication hole 128 in which the opening shape is an elliptical shape (the short axis is the height direction of the beam portion 122 and the long axis is the longitudinal direction of the beam portion 122). Although illustrated, the opening shape of the communication hole 128 is not limited to an elliptical shape, and other shapes can be applied.

  FIG. 10 is a cross-sectional view (a cross-sectional view taken along the line XX in FIG. 9) showing the three-dimensional structure of the print head 100. When the ink in the common liquid chamber 55 is circulated in the direction (from left to right in FIG. 10) from the circulation port 103A to the circulation port 103B shown in FIG. 7 (a), the assembly member 120 (beam In the region where the portion 122) does not exist and the region where the assembly member 120 is provided, the ink flow in the direction indicated by the white arrow line is generated, so that no stagnation point of the ink flow occurs in the vicinity of the beam portion 122. In addition, bubbles are prevented from staying in the vicinity of the stagnation point.

  In the print head 100 configured as described above, the beam portion 122 provided between the adjacent head chips of the assembly member 120 for connecting the plurality of head chips 50 passes through the beam portion 122 and is adjacent to the opening portion. Since the communication hole 128 for communicating 126 is provided, when the ink in the common liquid chamber 55 is circulated to eliminate the bubbles in the common liquid chamber 55, the inside of the common liquid chamber 55 (particularly in the vicinity of the beam portion 122). Therefore, it is possible to prevent the stagnation point of the ink flow from occurring and the bubbles from staying at the stagnation point to reduce the bubble evacuation property of the common liquid chamber 55. In addition, since an ink flow is generated over the entire area of the common liquid chamber 55, dissolution of bubbles contained in the ink into the ink is promoted by the ink flow.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. 11 shows a mode in which a plurality of communication holes 140 having a substantially circular planar shape are formed in the beam portion 122 of the assembly member 120 (not shown in FIG. 11, see FIG. 7B) according to the present embodiment. Show. In FIG. 11, only a part of the beam portion 122 and only a part of the head chip 50 are illustrated.

  In the aspect shown in FIG. 11, the beam section 122 has a communication hole row in which a plurality of communication holes 140 (two are shown in FIG. 11) are arranged along the longitudinal direction of the beam section 122. There are two rows of communicating holes in the vertical direction (the vertical direction in FIG. 11).

  In the aspect in which the plurality of communication holes 140 are provided in the beam portion 122 shown in FIG. 11, the communication holes 140 may be irregularly arranged on the communication hole forming surface 122A of the beam portion 122. Moreover, the opening size of the communication holes 140 may be the same, or the opening sizes of some of the communication holes 140 may be changed. FIG. 11 shows a mode in which the communication holes 140 having the same opening size are regularly arranged.

  Furthermore, the uppermost communication hole 140 may be a communication groove opened to the common liquid chamber 55, and the communication groove and the communication hole may be combined.

  Further, as shown in FIG. 12, the planar shape of the opening of the communication hole 142 may be a substantially rectangular shape having a long side along the longitudinal direction of the beam portion 122. In the aspect shown in FIG. 12, two (a plurality of) communication holes 142 are formed in the height direction of the beam portion 122 (vertical direction in FIG. 12).

  FIGS. 13A to 13B show structural examples of plate members when the beam portion 122 (assembly member 120) is formed by stacking plate members. The manufacturing method of forming the assembly member 120 by stacking plate members includes a step of forming plate members constituting the stack, a processing step of processing each plate member, and aligning each plate member A laminating step of laminating in a predetermined order and a joining step of joining the plate-like members are included.

  That is, the plate-like member 150 shown in FIG. 13 (a), the plate-like member 160 shown in FIG. 13 (b), and the plate-like member 170 shown in FIG. The plate-like member 160 and the plate-like member 170 are subjected to grooving (polishing and cutting if necessary), and the plate-like member 150, the plate-like member 160 and the plate-like member 170 are stacked while being aligned (necessary The plate member 150, the plate member 160, and the plate member 170 are joined (pressure treatment and heat treatment are performed as necessary), and the beam portion 122 shown in FIG. 11 is included. An assembly member 120 is formed.

  A plate-like member 150 shown in FIG. 13A has a groove 154 having a substantially semicircular cross-section on the lower surface 152 side. The groove 154 shown in FIG. 13A can be formed by half-etching from the lower surface 152 side.

  A plate-like member 160 shown in FIG. 13B has a groove 164 having a substantially semicircular cross section formed on the upper surface 162, and a groove 168 having a substantially semicircular cross section formed on the lower surface 166. Yes. The groove 164 of the plate member 160 is formed at the same position on the plane as the groove 154 of the plate member 150 shown in FIG. Thus, by combining grooves having a substantially semicircular cross-sectional shape, the communication hole 140 having a substantially circular opening shape shown in FIG. 11 can be easily and accurately formed. The plate-like member 160 shown in FIG. 13B can be easily formed by half-etching from both the upper surface 162 and the lower surface 166.

  Further, in the plate-like member 170 shown in FIG. 13C, a groove 174 having a substantially semicircular opening shape is formed on the upper surface 172. The groove 174 is formed on a plane with the groove 168 shown in FIG. Are formed at the same position.

  In this way, when the plate members 150, 160, and 170 shown in FIGS. 13A to 13C are stacked to form the assembly member 120 including the beam portion 122, a plurality of the same shapes and the same shapes shown in FIG. The assembly member 120 having the beam portion 122 provided with the communication hole 140 of the size can be easily manufactured. It is also possible to consider a mode in which the grooves 154 shown in FIG. 13A and the grooves 164 shown in FIG.

  FIGS. 14A to 14C show examples of the structure of the plate member when the assembly member 120 having the beam portion 122 shown in FIG. 12 is formed by stacking the plate members. The assembly member 120 shown in FIG. 12 has a plate-like member 180 in which a recess 184 is formed on the lower surface 182 shown in FIG. 14A, and no recesses are formed in the upper surface 192 and the lower surface 196 shown in FIG. A flat plate-like member 190 and a plate-like member 200 in which a concave portion 204 is formed on the upper surface 202 shown in FIG. 14C are combined.

  In this way, according to the aspect in which the beam portion 122 is provided with the plurality of communication holes 140 and 142, it is preferable because the ink flow in the short direction of the beam portion 122 can be created over the entire beam portion 122. Further, it is possible to form a groove or a recess in the upper surface 151 of the plate-like member 150 that is the uppermost surface shown in FIG. 13A or the upper surface 181 of the plate-like member 180 that is the uppermost surface shown in FIG. It is.

  As shown in FIGS. 11 and 12, when the beam portion 122 is provided with a plurality of communication holes, the variation in rigidity of the beam portion 122 (assembly member 120) is leveled by distributing the communication holes.

  For example, as shown in FIG. 15A, when the longitudinal positions of the beam portion 122 of the communication hole 142A and the communication hole 142B formed so as to be aligned in the height direction of the beam portion 122 are aligned, the communication hole 142 The portion where the is formed becomes easy to bend, and the wall portion 144 between the communication holes 142 becomes difficult to bend. Such a structure causes variations in hardness (rigidity) in the assembly member 120.

  On the other hand, as shown in FIG. 15 (b), when the longitudinal position of the beam portion 122 of the communication hole 142A and the longitudinal position of the beam portion 122 of the communication hole 142B are shifted and arranged, FIG. The hardness of the beam portion is leveled without variation in the hardness of the beam portion 122 (assembly member 120) as compared to the embodiment shown in FIG.

  In other words, when the first communication hole row 146 and the second communication hole row 148 are provided in the vertical direction which is the height direction of the beam portion 122, the first communication on the upper side in FIGS. 15 (a) and 15 (b). By staggering the longitudinal direction of the beam portion 122 between the hole row 146 and the second communication hole row 148 on the lower side in FIGS. 15A and 15B, the rigidity of the beam portion 122 is increased. Can be leveled. FIG. 15B shows a mode in which the first communication hole row 146 and the second communication hole row 148 are arranged with a 1/2 pitch shift from the communication holes. Furthermore, it is more preferable that the length in the longitudinal direction of the communication holes 142 is ½ of the pitch of the communication holes because the communication holes do not overlap with each other in the height direction of the beam portion 122.

That is, in the projection surface (illustration omitted) which projected the communication hole 142 shown in FIG.15 (b) on the joint surface of the beam part 122 and the head chip 50, adjacent communication holes (for example, communication hole 142A and communication hole 142B). the center-to-center distance P of), the communication hole 142A, the maximum length of the array direction 142B and _{L 1, L 2, P>} (L 1/2) + ( each communication so as to satisfy _L 2/2) When the holes are dispersedly arranged, the beam portion 122 does not have a portion having a large rigidity and a portion having a small rigidity, and the rigidity (hardness) of the beam portion 122 is leveled.

  According to the second embodiment described above, by providing a plurality of communication holes over the entire beam portion 122, the ink flow in the vicinity of the beam portion 122 over the entire beam portion 122 (the direction penetrating the beam portion 122 in the short direction). Ink flow). Moreover, the rigidity of the beam part 122 (assembly member 120) can be equalized by disperse | distributing and arrange | positioning several communicating holes.

  Further, as shown in FIG. 16 (a), the length in the height direction of the beam portion 122 (see FIG. 17) is larger than the length in the formation direction of the beam portion 122 (symbol x in FIGS. 17 (a) and (b)). When the communication hole 220 having a large symbol y) of 17 (a) and 17 (b) is provided, the beam portion 122 (assembly member 120) is less likely to bend than the embodiment shown in FIG. FIG. 16B shows a communication hole 222 having an approximately circular opening shape as one embodiment of the shape of the communication hole.

  Here, the length of the communicating portion formed in the beam portion 122 in the forming direction of the beam portion 122 (that is, the longitudinal direction of the beam portion 122) is x, and the length in the height direction of the beam portion 122 is y. When the aspect ratio of the hole is y / x, the aspect ratio of the communication hole 142 (see FIG. 12) shown in FIG. 17A is 1 or less, and the communication hole 220 (FIG. 16) shown in FIG. The aspect ratio of the reference) exceeds 1. Therefore, the aspect provided with the communication hole 220 long opened in the height direction of the beam part 122 (that is, the communication hole whose aspect ratio exceeds 1) has the communication hole 142 long open in the forming direction of the beam part 122. The assembly member 120 is less likely to bend as compared with an aspect provided with (a communication hole having an aspect ratio of 1 or less).

  As shown in FIGS. 18A and 18B, the communication hole having an elliptical opening shape has a diameter (maximum length) in the formation direction of the beam portion 122 x and the height direction of the beam portion 122. The aspect ratio is determined with the diameter (maximum length) as y. That is, the forming direction of the beam portion 122 is the end axis direction, and the height direction of the beam portion 122 is the long axis direction.

  As described with reference to FIGS. 16 to 18, if the communication hole is opened in the height direction of the beam portion 122 and the aspect ratio of the communication hole is increased, the beam portion 122 (assembly member 120) becomes difficult to bend, and the common liquid When the chamber member 102 (refer to FIG. 7A) and the head chip 50 (refer to FIG. 7B) and the assembly member 120 are bonded to each other, it is possible to prevent misalignment or bonding failure.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described. In the present embodiment, a mode is shown in which communication holes are formed in an oblique direction (obliquely downward direction) that forms an angle α with respect to the ink flow direction.

  FIG. 19 is a cross-sectional view (a cross-sectional view seen from the longitudinal direction of the print head) showing the three-dimensional structure of the print head 300 according to the third embodiment of the present invention. In the print head 300 shown in the figure, the communication hole 302 formed in the beam portion 122 is at an angle with respect to the main flow direction of ink in the common liquid chamber 55 (horizontal direction, indicated by a white arrow line in FIG. 19). It is formed in a diagonally downward direction forming α (shown by a black arrow line in FIG. 19).

  In the communication hole 302 shown in FIG. 19, the opening 306 on the downstream side of the ink flow is formed in the lower side in the vertical direction compared to the opening 304 on the upstream side in the direction of ink flow during circulation. It is formed obliquely downward with respect to the ink flow so as to communicate with the opening 306. The Reynolds number Re at the time of circulation is Re> 10. When the Reynolds number is large as described above, the downstream side is more likely to stagnate compared to the upstream side in the ink flow direction in the circulation.

  That is, when the ink in the common liquid chamber 55 is circulated in the direction of the white arrow in FIG. 19, it is compared with the upstream side of the ink flow of the beam portion 122 (the surface side where the opening 304 is formed, the left side in FIG. 19). Thus, the ink flow is relatively stagnation relatively on the downstream side of the ink flow (the surface on which the opening 306 is formed, the right side in FIG. 19). In particular, the lower side of the beam portion 122 on the downstream side of the ink flow (near the broken line circle indicated by reference numeral 308 in FIG. 19) tends to stagnate, so that the ink flow is directly guided to this portion. An opening 306 is formed below the downstream side surface of the ink flow of the beam portion 122.

  In order to form the communication hole 302 formed in the oblique direction shown in FIG. 19, the upstream side surface of the ink flow in the beam portion 122 is masked with a mask 320 as shown in FIG. (In FIG. 20, the processing direction is indicated by a broken-line arrow line), an obliquely downward communicating hole having an opening at a position corresponding to the hole 322 formed in the mask 320 is formed.

  It is difficult to form a communication hole in the horizontal direction in the beam portion 122 of the ladder-shaped assembly member 120 shown in FIG. 9 by drilling (that is, drilling from right next to the beam portion 122), as shown in FIG. It is also preferable from the viewpoint of the manufacturing method to form the communication hole in an oblique direction by the method. In FIG. 20, for the sake of illustration, the upstream side of the ink flow is on the left side, and the direction of ink flow is opposite to the drawings other than FIG.

  FIG. 21 shows another aspect of the present embodiment. That is, the print head 340 shown in FIG. 21 communicates with the first horizontal hole 342 in the horizontal direction in which an opening is formed on the upstream side surface of the ink flow in the beam portion 122 and the first horizontal hole 324 in the vertical direction. The first vertical hole 344 opened in the direction and the second vertical hole 344 and the second horizontal hole 346 having an opening formed on the downstream side of the ink flow of the communication beam portion 122 are combined to form a communication hole. It is configured.

  According to the aspect shown in FIG. 21, a plurality of communication holes are combined to form an opening below the downstream side of the ink flow of the beam portion 122, and the ink flow is directly introduced into a region where the ink flow is likely to stagnate. Further, the processing is easier than the embodiment shown in FIG.

  Further, a mode in which an upper part of the communication hole 302 shown in FIG. 19 is provided with a communication groove opened to the common liquid chamber 55 side is also possible. That is, the other end provided on the downstream side of the ink flow is lower in the vertical direction than the one end provided on the upstream side of the ink flow (the lower side in the vertical direction of the beam 122). A communication groove provided in the vicinity of the end portion of the head may be provided.

  According to the third embodiment described above, when the ink in the common liquid chamber 55 is circulated, the opening of the communication hole is provided in the lower stagnation portion of the beam portion 122 on the downstream side of the ink flow so that the ink is directly supplied. Thus, the ink flow in the vicinity of the beam portion 122 is prevented from being stagnation.

[Fourth Embodiment]
Next, a fourth embodiment according to the present invention will be described. FIG. 22 is a cross-sectional view of the print head 400 according to this embodiment (a cross-sectional view of the print head 340 viewed from the short side).

  As shown in FIG. 22, the assembly member 402 included in the print head 400 according to the present embodiment has a structure in which the height (vertical length) of the frame portion 404 constituting the periphery thereof is higher than other portions. have. Further, the height of the end portion 406 in the forming direction of the beam portion 405 (the height in the vicinity of the peripheral portion of the assembly member 402) has a beam portion 405 that is higher than other portions.

  In other words, the beam portion 405 has a height (maximum height) h ′ of the end portion 406 in the formation direction of the beam portion 405 that becomes a contact portion with the common liquid chamber member 102, and the height in the vicinity of the substantially central portion 408 of the beam portion 405. It is larger than (minimum height) h (h ′> h).

  As shown in FIG. 22, the common liquid chamber member 102 and the assembly member 402 are joined by a structure in which the height of the frame portion 404 and the height of the end portion in the formation direction of the beam portion 405 are made larger than those of other portions. Even when the assembly member 402 is pushed at this time, the assembly member 402 can be structured to be difficult to bend.

  In addition, the communication hole 410 provided at the end in the formation direction of the beam portion 405 has a larger diameter than the communication hole 140 provided in the substantially central portion. Thus, by increasing the diameter of the communication hole 410 in the vicinity of the end portion in the longitudinal direction of the beam portion 405, the occurrence of a stagnation point in the ink flow near the end portion in the longitudinal direction of the beam portion 405 is suppressed. It is preferable that the ratio of the diameter of the communication hole 410 to the diameter of the communication hole 140 is equal to the ratio of the maximum height h ′ of the beam portion 405 to the minimum height h of the beam portion 405.

  In this example, although the aspect which has the inclination part 412 in which the height of the edge part of the formation direction of the beam part 405 becomes large continuously was shown, the assembly member 302 is the minimum height surface and maximum height of the beam part 405. A structure in which the surfaces are connected to each other by a perpendicular surface (that is, a structure in which the cross-sectional shape in FIG. 22 is a concave shape) may be employed.

  According to the fourth embodiment described above, the strength of the joint portion with the common liquid chamber member 102 is increased by making the height of the end portion in the longitudinal direction of the beam portion 405 larger than the height of other portions. The bending of the assembly member 402 is suppressed. Further, by making the communication hole 410 provided in the end portion 406 in the longitudinal direction of the beam portion 405 larger than the other communication holes 140, stagnation of ink flow in the vicinity of the end portion 406 of the beam portion 405 is prevented.

[Fifth Embodiment]
Next, a fifth embodiment according to the invention will be described. FIG. 23 is a partial cross-sectional view of a print head 500 according to the fifth embodiment.

  An assembly member 502 shown in FIG. 23 has a protruding portion 504 that is inserted into a joint portion 104 (a gap formed between the head chips) of adjacent head chips 50, and the protruding portion 504 communicates with the beam portion 506. A dummy nozzle 508 communicating with the hole 140 is formed in a vertical direction (a direction substantially parallel to the forming direction of the nozzle 51 for ejecting ink, see FIG. 4).

  Further, the protrusion 504 has such a length that the surface of the protrusion 504 where the opening of the dummy nozzle 508 is formed is substantially the same position as the surface of the head chip 50 where the nozzle 51 is formed (see FIG. 4). Yes. That is, when the cap 64 shown in FIG. 5 is brought into contact with the nozzle forming surface of the head chip 50 and ink is sucked from the nozzle 51, bubbles in the communication hole 140 can be sucked from the dummy nozzle 508 at the same time.

  Further, the protrusion 504 may be used for positioning the head chip 50 and the assembly member 502. That is, the joint portion 104 (a gap formed between the head chips) of the adjacent head chips 50 can be used as an alignment hole, and the protrusion 504 of the assembly member 502 can be used as an alignment pin.

  The protrusion 504 may be omitted, and the dummy nozzle 508 communicating with the communication hole 140 provided in the beam 506 may be formed in the vertical direction.

  FIG. 24 shows a state where the assembly member 502 and the head chip 50 are separated (for example, a state before joining). FIG. 24 shows a mode in which the adhesive (sealing elastic member) 510 is applied to the assembly member 502, but the adhesive 510 may be applied to the head chip 50.

  Further, as shown in FIG. 25, a dummy nozzle 508 'penetrating on the opposite side (vertical upper side) from the protrusion 504 may be provided. A dummy nozzle 508 having a through hole as shown in FIG. 25 can be drilled from above the assembly member 502. In addition, instead of the communication hole 140 of FIG. 24, in the aspect provided with the communication groove open | released by the common liquid chamber 55 side (upper side of FIG. 24), it becomes a dummy nozzle 508 penetration structure inevitably.

As an example of the dimensions of the assembly member 502 of this example, the thickness w of the assembly member 502 is 0.5 mm to 1.0 mm, the width w ₁ of the protrusion 504 is approximately 0.3 mm, and the diameter of the dummy nozzle 508 is approximately. 0.1 mm.

  According to the fifth embodiment described above, ink is sucked from the nozzle 51 using the cap 64 by providing the dummy nozzle 508 that communicates with the communication hole 140 provided in the beam portion 506 and is formed vertically downward. At the same time, the gas staying in the communication hole 140 can be discharged to the outside from the dummy nozzle 508 via the cap 64 at the same time.

  Further, when a protrusion 504 that can be inserted between adjacent head chips 50 is provided and the dummy nozzle 508 is extended inside the protrusion 504, the protrusion 504 can be used as an alignment pin. 50 and the assembly member 502 can be easily aligned.

[Sixth Embodiment]
Next, a sixth embodiment according to the invention will be described. FIGS. 26A and 26B show a beam portion 600 that is a part of an assembly member according to the sixth embodiment. A porous member is used for the beam portion 600 shown in FIG. As described above, according to the aspect in which the porous member is used for the beam portion 600, the ink can pass through the beam portion 600 without providing the communication hole shown in FIG. It is possible to prevent the stagnation point from occurring.

  FIG. 26A shows a mode in which the entire beam portion 600 is formed of a porous member. However, the porous member may be applied to at least a part of the beam portion 600. When the entire beam portion 600 is formed of a porous member, the porous member applied to the beam portion 600 needs to have a predetermined rigidity in order to ensure the rigidity of the entire assembly member. Further, in a mode in which a part of the beam portion 600 is formed of a porous member, it is preferable to use a material having good ink permeability in order to prevent the occurrence of a stagnation point of ink flow. Furthermore, a mode in which a porous member having a predetermined rigidity and a porous member having good ink permeability is also possible. For the porous member, a material such as fiber metal or porous ceramic is preferably used.

  When a porous member is used for the beam portion 600, bubbles are mixed into the common liquid chamber 55 from the joint portion 104 of the adjacent head chip 50 through the porous member. As described above, it is preferable that the airtight member 602 is provided at the joint portion between the assembly member (beam portion 600) and the head chip 50 to prevent the porous member used for the beam portion 600 from coming into contact with the atmosphere.

  In the embodiment shown in FIG. 26 (a), the gas is mixed into the common liquid chamber 55 through the beam portion 600 of the porous member, so that the deaerated ink cannot be used. In the embodiment shown, since the air shielding member prevents bubbles from entering the common liquid chamber 55, it is possible to use deaerated ink, which is more preferable.

  For the airtight member shown in FIG. 26 (b), a metal film or silicon oxide is preferably used. That is, a metal film or a silicon oxide air-shielding member is deposited on the beam portion 600 shown in FIG. In addition, a mode in which a resin is used for the airtight member (a resin is coated on the beam portion 600) is also preferable.

  According to the sixth embodiment described above, by applying a porous member to a part or all of the beam portion 600 of the assembly member, ink can be passed without providing a communication hole in the beam portion 600. In addition, it is possible to prevent the stagnation point of the ink flow from occurring in the vicinity of the beam portion 600.

  Moreover, according to the aspect provided with the airtight member 602 in the portion of the beam portion 600 that comes into contact with the atmosphere, gas is prevented from being mixed into the common liquid chamber 55 from the joint portion 104 of the adjacent head chip 50. More preferred.

[Application example]
Next, application examples of the above-described first to sixth embodiments will be described. A chamfering process is applied to a corner portion 622 on the side surface opposite to the surface to be joined to the head chip 50 of the beam portion 620 shown in FIG. By forming the communication hole 140 in the beam portion 620, the thickness t of the beam portion 620 can be increased, and the corner portion 622 can be chamfered.

  In this way, by chamfering the beam portion 620 on the common liquid chamber 55 side, the ink flow in the chamfered portion becomes smooth. In FIG. 27, R chamfering is illustrated as an example of chamfering, but C chamfering may be applied.

  In the embodiment of the present invention described above, the ink jet recording apparatus 10 that forms a color image on the recording paper 16 by ejecting ink droplets on the recording paper 16 has been described. However, the scope of the present invention is applied to the ink jet recording apparatus. The present invention is not limited, and the present invention can be applied to a liquid discharge apparatus that discharges liquids such as water, chemical liquid, and processing liquid from discharge holes (nozzles) provided in the head.

  In the above-described embodiment, a full-line type head in which a plurality of head chips 50 are arranged in the width direction of the recording paper 16 (a direction orthogonal to the paper feeding direction) is shown. However, a plurality of head chips are arranged in the paper feeding direction. The present invention is also applicable to a serial type head that performs printing in the width direction of the recording paper 16 while scanning the print head in which 50 is arranged in the head chip arrangement direction (that is, the width direction of the recording paper 16).

1 is a basic configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 1 is a plan view of the main part around the printing of the ink jet recording apparatus shown in FIG. Plane perspective view showing structural example of print head Diagram showing the three-dimensional structure of the head chip Schematic diagram showing the configuration of an ink supply system in the ink jet recording apparatus shown in FIG. 1 is a principal block diagram showing the system configuration of the ink jet recording apparatus shown in FIG. 1 is an exploded perspective view showing a structure of a print head according to a first embodiment of the present invention. Cross-sectional view of the main part of the print head shown in FIG. The perspective view which shows the structure of the assembly member shown in FIG. Sectional view of the print head shown in FIG. The principal part perspective view of the print head which concerns on 2nd Embodiment of this invention. The principal part perspective view which shows the other aspect of the communicating hole shown in FIG. FIG. 11 is an exploded perspective view of the beam portion shown in FIG. 12 is an exploded perspective view of the beam portion shown in FIG. The figure explaining the example of arrangement of a communicating hole 11 and 12 are main part perspective views showing other modes of the communication holes shown in FIGS. Diagram explaining the aspect ratio of the rectangular communication hole Illustration explaining the aspect ratio of the ellipse communication hole Sectional drawing which shows the structure of the print head which concerns on 3rd Embodiment of this invention. The figure explaining the example of a formation method of the communicating hole shown in FIG. Sectional drawing which shows the other aspect of the communicating hole shown in FIG. Sectional drawing of the print head which concerns on 4th Embodiment of this invention. Sectional drawing of the print head which concerns on 5th Embodiment of this invention. Exploded view of the print head shown in FIG. Sectional drawing which shows the other aspect of the dummy nozzle shown in FIG. Perspective view of essential parts of a print head according to a sixth embodiment of the present invention. The principal part perspective view of the print head which concerns on the application example of this invention Perspective perspective view showing a print head according to the prior art FIG. 28 is a perspective view showing another embodiment of the print head shown in FIG.

Explanation of symbols

1, 6, 100, 300, 400, 500 ... print head, 2, 120, 402, 502 ... assembly member, 3, 122, 405, 506, 600 ... beam, 10 ... inkjet recording apparatus, 50 ... head chip, DESCRIPTION OF SYMBOLS 51 ... Nozzle, 55 ... Common liquid chamber, 56 ... Pressure plate, 58 ... Pressure generating element, 102 ... Common liquid chamber member, 128, 140, 142, 142A, 142B, 220, 221, 222, 302, 342, 344 346, 410 ... communication hole, 504 ... projection, 508 ... dummy nozzle, 602 ... airtight member

Claims (12)

A long liquid discharge head having a structure in which a plurality of head chips each having a nozzle for discharging a liquid are connected,
A plurality of openings corresponding to the head chips, an assembly member that joins the plurality of head chips in a predetermined arrangement by joining to a surface opposite to the liquid ejection direction of the head chips;
A common liquid chamber for supplying a liquid to the plurality of head chips, and a common liquid chamber member bonded to a side surface opposite to the surface to which the head chip of the assembly member is bonded;
With
The liquid ejection head according to claim 1, wherein the assembly member is formed with a flow path communicating with an opening adjacent to a beam portion separating adjacent openings.   The liquid discharge head according to claim 1, wherein the flow path is a through hole penetrating the beam portion. The beam portion is provided with a plurality of the flow paths,
In the projection plane obtained by projecting the plurality of channels on the joint surface between the beam portion and the head chip, the distance P between the centers of the adjacent channels is the maximum length in the arrangement direction of the two adjacent channels. When _L 1, _{L 2} respectively, the following equation _{P> (L 1/2)} + (L 2/2)
The liquid discharge head according to claim 1, wherein the plurality of flow paths are dispersedly arranged so as to satisfy the above condition.   The cross-sectional surface shape of the flow path in the plane orthogonal to the flow path formation direction is such that the ratio of the maximum length in the height direction of the beam portion to the maximum length in the formation direction of the beam portion exceeds 1. The liquid discharge head according to claim 1, 2 or 3. One end of the flow path is provided near the lower end in the height direction of the beam portion,
When the liquid stored in the common liquid chamber is circulated in the circulation direction along the longitudinal direction of the liquid discharge head, an end portion of the flow path is formed in the vicinity of the lower end portion in the height direction of the beam portion. 5. The liquid discharge head according to claim 1, wherein the liquid stored in the common liquid chamber is circulated so that a side thereof is a downstream side in the circulation direction.   6. The liquid ejection head according to claim 1, wherein the assembly member has a structure in which a height of a peripheral portion and a vicinity of the peripheral portion is higher than a height of other portions. The beam portion includes a dummy nozzle formed in a direction substantially parallel to the nozzle forming direction of the head chip,
The dummy nozzle has a structure in which one end portion communicates with the flow path and the other end portion communicates with the atmosphere in a non-joining region with a head chip on a joint surface with the head chip. The liquid discharge head according to claim 1. The assembly member includes a protrusion that can be inserted between adjacent head chips,
The protrusion includes a dummy nozzle formed in a direction substantially parallel to the nozzle forming direction of the head chip,
The dummy nozzle has a structure in which one end communicates with the flow path, the other end reaches the tip of the projection, and communicates with the atmosphere at the other end. Item 7. The liquid discharge head according to any one of Items 1 to 6.   The liquid discharge head according to claim 7, wherein the dummy nozzle has a length that intersects the flow path and penetrates the beam portion. A long liquid discharge head having a structure in which a plurality of head chips each having a nozzle for discharging a liquid are connected,
A plurality of openings corresponding to the head chips, an assembly member that joins the plurality of head chips in a predetermined arrangement by joining to a surface opposite to the liquid ejection direction of the head chips;
A common liquid chamber for supplying a liquid to the plurality of head chips, and a common liquid chamber member bonded to a side surface opposite to the surface to which the head chip of the assembly member is bonded;
With
The assembly member is a liquid discharge head, wherein a porous member is used in a beam portion that separates adjacent openings.   The liquid ejection head according to claim 10, wherein the beam portion includes an airtight member on a joint surface with the head chip.   A liquid discharge apparatus comprising the liquid discharge head according to claim 1.

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