JP2007276165A - Liquid droplet discharging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable individual suction of a nozzle unit in relation to a liquid droplet discharging apparatus. <P>SOLUTION: Each suction opening 504 has an approximately square with four corner parts being R. Long sides 504A are a little narrower in width than the interval M of rows of nozzles 122, and short sides 504B are a little narrower in width than the interval d of lines. When seen in the conveying direction A (the direction orthogonal to the row direction B) for a recording paper P, each suction opening 504 covers the nozzle row of each nozzle 122 arranged in the row direction C (one nozzle row is covered by one suction opening 504). The suction openings 504 like this are arranged in a row in the line direction B. Therefore, when the wiping blade 500 is wiped in the conveying direction A for the recording paper P (the direction orthogonal to the line direction B) like a wiping blade 500 indicated by an imaginary line in a figure, it is possible to cover each only one nozzle 122 by each suction opening 504. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a droplet discharge device.

  Ink jet recording heads may generate defective ejection nozzles such as no ink droplets being ejected from the nozzles. The causes of defective ejection nozzles include bubbles, foreign matter such as dust, and ink thickening. Of these, unlike other causes, bubbles are difficult to eradicate by improving the cleanliness of manufacturing facilities and optimizing maintenance.

  In order to mix bubbles, ink suction that sucks ink from the nozzles and discharges the bubbles together with the ink is effective. (Ink suction is also effective for mixing foreign substances and increasing the viscosity of ink).

  However, in the ink jet recording head having a large number of nozzles, a large number of inks are easily sucked simultaneously from other (no air bubbles) nozzles. Then, the ink is more easily sucked from the other nozzle (having no bubble mixing) having a low flow path resistance. Therefore, more ink than necessary is consumed, and a recovery effect such as a bubble discharge effect due to ink suction cannot be obtained sufficiently. For this reason, individual suction for individually sucking each nozzle is required.

  Now, a so-called FWA (Full Width Array) system has a long ink jet recording head having a width substantially equal to the width of the recording paper, and the ink jet recording head performs recording while transporting only the recording medium. An ink jet recording apparatus has been proposed. Since many of these FWA methods are one-pass printing methods, if there is a defective ejection nozzle, it is easy for the user to recognize as an image defect, and the influence is great.

  In addition, various methods have been proposed in which the nozzle surface of an ink jet recording head is wiped with an elastic blade to clean ink, dust, etc. adhering to the nozzle surface. (For example, see Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4).

Furthermore, there has been proposed a method for improving the recoverability of ink or dust adhering to the nozzle surface by suction from an air suction through hole opened on the contact surface side of the nozzle surface of the elastic blade. (For example, refer to Patent Document 5).
Patent 035554099 Japanese Patent Laid-Open No. 04-235054 JP 2001-071513 A JP 2001-347679 A JP-A-6-115083

In JP-A-6-115083, as shown in FIG. 15, in an inkjet recording head 900 including a nozzle surface 900A on which nozzles 902 arranged in a line are formed,
(1) When wiping with a blade 907 perpendicular to the nozzle arrangement direction (see arrow X in the figure),
(2) When wiping with the blade 905 in the arrangement direction of the multi-nozzles (see arrow Y in the figure),
Is described.

  In the case of such a configuration, in the wiping of (1), in order to enable individual suction, the air suction through hole 909 is a very small opening having a width equal to or less than the nozzle pitch L.

  In order to enable individual suction even with the wiping of (2), the air suction through-hole 903 is a very small opening having a width equal to or less than the nozzle pitch L. Further, it is necessary to feed the wiping blade at the nozzle pitch L.

  Therefore, the higher the resolution, that is, the higher the nozzle density, the smaller the air suction through hole. For example, at 600 dpi, the nozzle pitch L is 42 μm. (For the sake of clarity, the nozzle 902 and the air suction through-holes 903 and 909 are greatly illustrated in the figure).

  However, in practice, it is very difficult to form such a very small opening for air suction at the tip of the wiping blade. That is, in the configuration of Japanese Patent Laid-Open No. 6-115083, individual suction in units of nozzles is very difficult and is not practical.

  The present invention has been made to solve the above problems, and an object thereof is to enable individual suction in units of nozzles.

  In order to achieve the above object, the droplet discharge device according to claim 1 is a nozzle surface on which nozzles arranged in a matrix are formed with a direction perpendicular to the row direction and a direction having an angle as a column direction. A droplet discharge head comprising: a sliding member that slides the nozzle surface in a direction orthogonal to the row direction; and an end portion on the contact surface side of the sliding member with the nozzle surface in the row direction A plurality of suctions that are arranged side by side, cover a plurality of nozzles so as not to straddle two nozzle rows when viewed in a direction perpendicular to the row direction of the nozzles, and can suck liquid from the nozzles And a mouth.

  In the liquid droplet ejection apparatus according to claim 1, the liquid droplet ejection head includes a nozzle surface on which nozzles arranged in a matrix are formed with a direction perpendicular to the row direction and an angle as a column direction. Yes.

  The sliding member is provided with a plurality of suction ports arranged in the row direction at the end on the contact surface side with the nozzle surface. The suction port is narrower than the row interval of the nozzles, and covers a plurality of nozzles without straddling two nozzle rows when viewed in a direction orthogonal to the row direction. Accordingly, when the nozzle surface is slid in the direction orthogonal to the row direction, only one nozzle is accommodated in each suction port. Therefore, it is possible to perform individual suction in which only one nozzle is individually sucked by one suction port. For this reason, for example, when a plurality of nozzles including nozzles clogged with nozzles are sucked by one suction port, the influence due to the difference in flow path resistance is small. Therefore, the ejection failure nozzle is smoothly recovered by ink suction.

  Now, the nozzles of the droplet discharge head have a high density when viewed in the direction perpendicular to the row direction. That is, the nozzle pitch when viewed in this way is the resolution (dot pitch). Therefore, although the resolution is high, the space between the nozzle rows is larger than the resolution. Furthermore, the intervals between the plurality of nozzles are wide. Therefore, the suction port can be made much larger than the resolution (dot pitch).

  In addition, by adopting a configuration in which each suction port can be sucked individually, it is possible to select and suck only a desired nozzle.

  The droplet discharge head may be fixed and the sliding member may move to slide the nozzle surface, the sliding member may be fixed and the droplet discharge head may move, or the sliding member And the droplet discharge head may move.

  According to a second aspect of the present invention, in the configuration of the first aspect, the droplet discharge head is provided along the row direction of the nozzles, and includes a plurality of tributaries in which the plurality of nozzles communicate with each other. It is characterized by having.

  According to a second aspect of the present invention, the droplet discharge head includes a plurality of tributaries that are provided along the nozzle row direction and that communicate with the plurality of nozzles. That is, since each suction port sucks nozzles of different tributaries, the influence due to the difference in flow path resistance is further reduced.

  According to a third aspect of the present invention, in the liquid droplet ejection device according to the first or second aspect, the sliding member stops at the row interval pitch of the nozzles and sucks the liquid from the nozzles. It is characterized by that.

  In the droplet discharge device according to the third aspect, the sliding member moves and stops at the row interval pitch of the nozzles, and sucks the liquid from the nozzles.

  According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the adjacent suction ports are provided so as to be shifted in a direction orthogonal to the row direction. It is characterized by that.

  In the droplet discharge device according to the fourth aspect, the adjacent suction ports are shifted in the direction orthogonal to the row direction. Therefore, the space between the suction ports arranged in the row direction can be narrowed.

  According to a fifth aspect of the present invention, in the liquid droplet ejection device according to any one of the first to fourth aspects of the present invention, the liquid droplet ejection device includes a detection unit that detects a defective ejection nozzle that has failed to eject a liquid droplet. 5. The liquid droplet ejection apparatus according to claim 1, wherein only the defective ejection nozzles detected by the means are selectively sucked. 6.

  In the droplet discharge device according to the fifth aspect, only the defective discharge nozzles detected by the detection means are selectively sucked. Therefore, liquid is not sucked from a nozzle that does not require suction.

  According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the detection unit forms a predetermined pattern on the inspection discharge target with the liquid droplets, and the inspection discharge target is formed on the inspection discharge target. The predetermined pattern formed is read to detect the ejection failure nozzle.

  In the droplet discharge device according to the sixth aspect, the detection means reads a predetermined pattern of the inspection object to be detected and detects a defective discharge nozzle.

  According to a seventh aspect of the present invention, in the configuration of the sixth aspect, the inspection discharge target is a recording medium on which an image is formed by liquid droplets.

  In the droplet discharge device according to the seventh aspect, since a recording medium on which an image is formed by droplets is used as the inspection discharge object, a separate inspection discharge object is not necessary.

  The droplet discharge device according to claim 8 is the configuration according to claim 6, wherein the inspection discharge target is provided to face the nozzle surface of the droplet discharge head, and an image is formed by the droplet. It is a conveyance belt for conveying a recording medium to be formed.

  In the droplet discharge device according to the eighth aspect, since the conveyance belt is used as the inspection discharge object, no separate inspection discharge object is required.

  The droplet discharge device according to claim 9 is the configuration according to any one of claims 1 to 7, wherein a counterbore is formed around the nozzle of the droplet discharge head. It is characterized by.

  In the droplet discharge device according to the ninth aspect, counterbore is formed around the nozzle of the droplet discharge head. Therefore, even if the sliding member slides on the nozzle surface, for example, breakage of the liquid repellent film around the nozzle due to mechanical friction is prevented.

  The liquid droplet ejection device according to claim 10 is the configuration according to any one of claims 1 to 9, wherein the sliding member also serves as a wiping blade for wiping the nozzle surface. It is said.

  In the droplet discharge device according to the tenth aspect, since the sliding member also serves as a wiping blade for wiping the nozzle surface, the number of parts is small.

  The droplet discharge device according to claim 11 is the configuration according to claims 1 to 10, wherein the row direction is a direction orthogonal to a conveyance direction of a recording medium on which an image is formed by droplets, The droplet discharge area in the row direction of the droplet discharge head is equal to or larger than the recording area width of the recording medium, and the droplet discharge head discharges droplets onto the conveyed recording medium in a state where the droplet discharge head is fixed. It is characterized by forming an image.

  In the droplet discharge device according to the eleventh aspect, the row direction is a direction orthogonal to the conveyance direction of the recording medium on which an image is formed by droplets. Further, the droplet discharge area in the row direction of the droplet discharge head is equal to or larger than the recording area width of the recording medium. An image is formed over a wide range in a short time by ejecting droplets onto a recording medium conveyed with the droplet ejection head fixed and forming an image by a one-pass printing method.

  Also, since individual suction is possible, bubbles can be discharged smoothly. For this reason, an ejection failure nozzle can be recovered easily. For this reason, even if it is a 1 pass printing system in which a user is easily recognized as an image defect when there is a defective ejection nozzle, no problem occurs.

  As described above, according to the present invention, the suction port can be made much larger than the resolution, so that individual suction can be performed in units of nozzles.

  FIG. 1 shows an ink jet recording apparatus 12 of the present embodiment. The ink jet recording apparatus 12 includes a control unit 8 that includes a CPU, a ROM, a RAM, and the like. The control unit 8 controls various controls of the entire apparatus. In addition, an operation panel 11 for displaying various information to the user and performing various operations is provided on the upper part of the front of the apparatus.

  A paper feed tray 16 is provided at the lower part of the ink jet recording apparatus 12, and the recording paper P stacked in the paper feed tray 16 can be taken out one by one by a pickup roll 18. The taken recording paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22.

  Above the paper feed tray 16, an endless transport belt 28 stretched around a drive roll 24 and a driven roll 26 is disposed. A recording head array 30 is disposed above the conveyor belt 28 and faces the flat portion 28F of the conveyor belt 28. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The recording paper P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information adhere from the recording head array 30 in a state of facing the recording head array 30. Is done.

  In the present embodiment, the recording head array 30 has a long shape in which the effective recording area is equal to or larger than the width of the recording paper P (the length in the direction orthogonal to the transport direction), and yellow (Y), magenta (M ), Four ink jet recording heads 32 corresponding to four colors of Sian (S) and black (K) are arranged along the transport direction, and a full color image can be recorded. (See also FIG. 4).

  Each inkjet recording head 32 is controlled by the control unit 8. For example, the control unit 8 determines the ejection timing of the ink droplets and the nozzle 122 (see FIGS. 5 and 6) to be used according to the image information, and sends a drive signal to the inkjet recording head 32.

  The recording head array 30 is not moved in a direction orthogonal to the transport direction A (one-pass printing method). However, if it is configured to move as necessary in the direction orthogonal to the transport direction A, an image with higher resolution can be recorded by multi-pass image recording, or a defect in the inkjet recording head 32 can be recorded. It is also possible to prevent it from being reflected in.

  Four maintenance units 34 corresponding to the respective ink jet recording heads 32 are arranged on both sides of the recording head array 30. When maintenance is performed on the inkjet recording head 32, the recording head array 30 moves upward as shown in FIG. 2, and the maintenance unit 34 moves to a gap formed between the conveyance belt 28 and the maintenance unit 34. Get in. Then, a predetermined maintenance operation (vacuum, dummy jet, wiping, capping, etc.) is performed while facing the nozzle surface 32N (see FIG. 3).

  As shown in FIG. 3, a charging roll 36 to which a power source 38 is connected is disposed on the upstream side of the recording head array 30. The charging roll 36 is driven while sandwiching the conveyance belt 28 and the recording paper P with the driven roll 26, and is between a pressing position for pressing the recording paper P against the conveyance belt 28 and a separation position separated from the conveyance belt 28. Can be moved. In the pressing position, a predetermined potential difference is generated between the grounded driven roll 26 and the recording paper P can be charged and electrostatically attracted to the transport belt 28.

  A peeling plate 40 is disposed on the downstream side of the recording head array 30, and the recording paper P is peeled from the conveyance belt 28. The peeled recording paper P is conveyed by a plurality of discharge roller pairs 42 constituting a discharge path 44 on the downstream side of the peeling plate 40 and discharged to a paper discharge tray 46.

  As shown in FIG. 1 and FIG. 2, above the recording head array 30, four colors of yellow (Y), magenta (M), cyan (S), and black (K) corresponding to each inkjet recording head 32 are provided. An ink tank 54 is provided. An ink flow path 200 connects each ink tank 54 and each ink jet recording head 32. Each color ink stored in each ink tank 54 passes through the ink flow path 200, is filtered by a filter device (not shown), and is supplied to each inkjet recording head 32.

  Next, the ink jet recording head 32 will be described.

  As shown in FIG. 4, the ink jet recording head 32 includes a head bar 112 set to a length corresponding to the maximum width of the recording paper P. The head bar 112 is fixedly supported by a support body (not shown) at a position facing the conveyance path of the recording paper P in the ink jet recording apparatus 12. The head bar 112 is provided with a plurality of head units 114 connected to a support member 113 in a line. Each head unit 114 is fastened to the support member 113 with screws (not shown), and can be individually replaced. The recording paper P is transported in the transport direction A direction indicated by an arrow A in the figure, and is configured to be printed by each head unit 114 disposed on the support member 113. That is, when the recording paper P passes once below the head bar 112, the entire width of the recording paper P can be printed without scanning the ink jet recording head 32 (recording head array 30).

  As shown in FIGS. 4 and 5, the head unit 114 has a substantially parallelogram shape, and two element substrates 116 and 118 are disposed on the upper surface of the head unit 114. The two element substrates 116 and 118 have a substantially trapezoidal shape, and are arranged in the head unit 114 so that the oblique sides (short oblique sides) having the same length of the substantially trapezoidal shape face each other. The element substrates 116 and 118 are configured such that the inner angle formed by the short hypotenuse is larger than the outer angle formed by the long hypotenuse. The head unit 114 has extended portions 120A and 120B in which two obtuse angle portions of a substantially parallelogram project outward, so that the gap between the edge of the head unit 114 and the element substrates 116 and 118 is not narrowed. A predetermined width is secured. Further, the head unit 114 includes angled portions 121A and 121B in which two acute angle portions of a substantially parallelogram are cut. As shown in FIG. 4, when a plurality of head units 114 are connected in a row, adjacent extending portions 120A and 120B and cornered portions 121A and 121B are configured to face each other.

  As shown in FIG. 5, nozzle regions 124 </ b> A and 124 </ b> B in which a plurality of nozzles 122 are disposed are formed on the opposite side of the element substrates 116 and 118 (see FIG. 4) of the head unit 114. That is, the element substrates 116 and 118 are provided at positions corresponding to the two nozzle regions 124A and 124B, and ink droplets are ejected from the nozzles 122 into the substantially trapezoidal regions of the element substrates 116 and 118. A piezoelectric element group (not shown) is formed.

  As shown in FIG. 6, the nozzle plate 130 is formed with nozzles 122 that eject ink droplets. A communication hole 154 that communicates with the nozzle 122 is formed in the communication hole plate 132, and a communication hole 156 is formed in the damper member 134. The pool plates 136, 138, and 140 are formed with communication holes 158, 160, and 162, respectively, and the communication hole plate 142 is formed with a communication hole 164. Further, a communication hole 166 is formed in the flow path plate 144, and a communication hole 168 is formed in the communication hole plate 142. These nozzles 122, communication holes 154, 156, 158, 160, 162, 164, 166, 168 communicate with each other and are connected to a pressure chamber 170 formed in the pressure chamber plate 148.

  On the other hand, in the communication hole plate 132, a hollow portion 172 is formed below the damper member 134. The pool plates 136, 138, and 140 are formed with ink pools 174, 176, and 178, respectively, and store ink supplied from ink supply holes (not shown). The ink pools 174, 176, 178, the supply hole 180, the ink flow path 182, the supply hole 184, and the pressure chamber 170 communicate with each other, and ink enters the pressure chamber 170 from the ink pools 174, 176, 178. Is supplied.

  Further, a piezoelectric element 186 is attached to the upper part of the vibration plate 150 so that a driving voltage is applied from the flexible wiring board. These piezoelectric elements 186 are respectively provided above the pressure chambers 170 communicating with the individual nozzles 122, and a piezoelectric element group constituted by a large number of piezoelectric elements 86 is connected to the element substrates 116 and 118 shown in FIG. It has become.

  The nozzle surface 32N is coated with a liquid repellent film (not shown) that repels ink. Further, a counterbore 123 is formed around the nozzle 122. (See FIG. 6B). The counterbore 123 is not shown in the drawings other than FIG.

  Now, the ink pools 174, 176, 178 are combined into a common ink flow path 214. Further, the piezoelectric element 186, the pressure chamber 170, the diaphragm 150 corresponding to the pressure chamber 170, and the pressure chamber 170 to the nozzle 122 are combined to form an ejector 260.

  Therefore, as shown in FIG. 7, a plurality of ejectors 260 are connected to the common ink flow path 214.

  The ink in the ink tank 54 is introduced into the manifold 250 from the ink inlet 272 through the ink flow path 200. In the manifold 250, a plurality of common ink channels 214 extend in parallel on the same plane. In other words, if the manifold 250 is a main stream, the common ink flow path 214 is a tributary branching from the manifold 250. FIG. 8 is an enlarged view of the flow end portion of the common ink flow path 214 of FIG.

  Note that, corresponding to the nozzle regions 124A and 124B (see FIG. 5), the vertex of the common ink flow path 214 has a trapezoidal shape such that the end side is a vertex of the convex portion slightly from the center.

  Since it has such a configuration, when viewed in plan, the nozzles 122 are arranged in a matrix in a grid pattern.

  As shown in FIG. 5, the nozzles 122 arranged in a matrix in a grid pattern are such that the row direction B is perpendicular to the conveyance direction A of the recording paper P, and the column direction C is the conveyance direction A of the recording paper P. Has an angle θ.

  Now, as shown in FIG. 5B, when the nozzles 122 are projected in the conveyance direction A of the recording paper P, the nozzles 122 are arranged in a high density. Similarly, as shown in FIG. 14, the boundary between the head units 114 is the same.

  Then, when the recording paper P passes under the ink jet recording head 32, a high resolution image is formed by ejecting ink droplets from the nozzles 122 in order. That is, the pitch of the nozzles 122 when viewed in this way is the resolution (dot pitch).

  Further, as shown in FIG. 9, the row interval d of the nozzles 122 is wider than the resolution. Further, the nozzle pitch m in the row direction C of the nozzles 122 is equal to the resolution, but the nozzle row interval M is wider than the resolution.

  Each common ink flow path 214 is along the column direction C of the nozzles 112. (The common ink flow path 214 and the column direction C are substantially the same direction). However, FIGS. 7 and 8 schematically illustrate the common ink channel 214 without providing an angle for the sake of clarity.

  As shown in FIGS. 4 and 5, the nozzle row is not continuous at the boundary between the nozzle regions 124A and 124B and the boundary between the head units 114, but this is also a single nozzle row.

  As described above, as shown in FIGS. 1 and 2, in the inkjet recording apparatus 12, the maintenance unit 34 moves and enters under the recording head array 30, and faces the nozzle surface 32N (see FIG. 3). Then, a predetermined maintenance operation (vacuum, dummy jet, wiping, capping, etc.) is performed.

  As shown in FIGS. 10 and 11, the maintenance unit 34 (see FIGS. 1 and 2) includes a wiping blade 500 for wiping the nozzle surface 32N.

  The wiping blade 500 is a plate-like elastic blade made of rubber such as urethane. The wiping blade 500 has a length that can cover all the nozzles 122 (see FIG. 4 and the like) in the row direction B. Then, the nozzle surface 32N is wiped in the same direction as the conveyance direction A of the recording paper P, that is, the direction orthogonal to the row direction B, and ink and dust adhering to the nozzle surface 32N are wiped off. (See FIG. 10A).

  As shown in FIG. 10B, the end of the wiping blade 500 on the side contacting the nozzle surface 32N is formed with tapered surfaces 503 on the left and right (conveying direction A), leaving the central flat portion 502. Suction ports 504 are formed in the left and right tapered surfaces 503, respectively.

  As shown in FIGS. 9 and 11, a plurality of the suction ports 504 are formed side by side in the row direction B. In FIG. 11, the suction port 504 is shown larger than the actual size for easy understanding.

  As shown in FIGS. 10 and 11, each suction port 504 communicates with a suction path 506 formed in the wiping blade 500. A suction tube 508 communicates with the suction path 506, and a valve 510 is provided for each. Each suction tube 508 is connected to the suction pump 512 after becoming one. The suction pump 512 and each valve 510 are controlled by the control unit 8 (see FIGS. 1 and 2). Further, the suction tube 508, the valve 510, the suction pump, and the like are used as a suction machine groove.

  As shown in FIG. 9, each suction port 504 has a substantially rectangular shape with corners of the four corners being R. The long side 504A is slightly narrower than the column interval M of the nozzles 122, and the short side 504B is slightly narrower than the row interval d. Further, when viewed in the conveyance direction A (direction orthogonal to the row direction B) of the recording paper P, each suction port 504 covers the nozzle row of each nozzle 122 arranged in the column direction C. . In other words, one suction port 504 covers one nozzle row and does not straddle two nozzle rows. Such suction ports 504 are formed in a row in the row direction B.

  Therefore, when the wiping blade 500 is wiped in the conveyance direction A (direction orthogonal to the row direction B) of the recording paper P, like the wiping blade 500 indicated by an imaginary line in the drawing, each suction port 504 has one nozzle 122. It is possible to cover only.

  Further, as shown in FIGS. 1 and 2, the reading sensor 7 is disposed on the upstream side of the maintenance unit 34. Then, a predetermined pattern is formed on the recording paper P, and the reading sensor 7 reads the predetermined pattern, so that an ink foe is ejected normally such as an ejection failure nozzle (non-ejection or very small ink droplets). No nozzle) can be detected and specified by the control unit 8.

  Next, the operation of this embodiment will be described.

  As shown in FIG. 10, when the nozzle surface 32N is wiped by the wiping blade 500 in the conveyance direction A (direction orthogonal to the row direction B) of the recording paper P, each suction port 504 has one suction port 504 as shown in FIG. Only the nozzle 122 is covered. That is, individual suction in which one suction port 504 sucks one nozzle 122 is performed. For this reason, compared with the case of simultaneously sucking from a plurality of nozzles, a difference in ink suction due to a difference in flow path resistance due to the presence or absence of nozzle clogging is less likely to occur. Therefore, ink suction is effectively performed.

  In particular, in this embodiment, each suction port 504 sucks the nozzles 122 of different common ink flow paths (branches) 214 as shown in FIGS. Less. That is, the ejection failure nozzle is smoothly recovered by ink suction.

  In the suction port 504, the long side 504A is slightly narrower than the column interval M of the nozzles 122, and the short side 504B is slightly narrower than the row interval d.

  However, the row interval M is the nozzle 122 communicating with the common ink flow path 214, that is, the number of nozzles in one row multiplied by the nozzle pitch m (resolution).

  Furthermore, the row interval d is also wider than when the nozzles are arranged in a single row in a row (see FIG. 15). For example, even if the resolution is 600 dpi, the row interval d can be set to 0.5 mm or more if the length of one common ink channel 214 is allowed to be about 20 mm.

  Thus, the suction port 504 is much larger than the resolution (dot density on the recording paper P). Therefore, the suction port 504 has a size that can be formed easily.

  In this way, high resolution is realized without arranging the nozzles themselves at high density, and individual suction is realized (both high resolution and individual suction are realized).

  As shown in FIG. 6, counterbore 123 is formed around the nozzle 122. Therefore, for example, the liquid repellent film around the nozzle 122 is prevented from being destroyed by mechanical friction due to rubbing of the recording paper P, wiping by the wiping blade 500, or the like.

  Note that suction may be performed while scanning the wiping blade 500. However, ink suction can be performed more reliably if the ink suction is performed after stopping at the line interval d pitch. Note that the movement pitch of the wiping blade 500, that is, the line interval d is wider than the resolution as described above, and is a movement pitch that can be controlled sufficiently easily. (See FIGS. 8 and 9).

  Further, as shown in FIG. 11, by controlling the suction pump 512 and the valve 510, selective suction for selecting and sucking only a specific nozzle 122 is also possible. For example, when the nozzle 122X in FIG. 9 is selectively sucked, the suction pump 512 is operated only in this row, and only the nozzle 122X is opened by opening only the valve 510 communicating with the suction port 504X covering the nozzle 122X. Can be selectively sucked.

  In addition, a predetermined pattern is formed on the recording paper P, and the reading sensor 7 reads the predetermined pattern, so that the control unit 8 detects and specifies the ejection failure nozzle, and only the identified ejection failure nozzle is detected. It is also possible to perform selective suction.

  Next, a modification of this embodiment will be described.

  First, the first modification will be described.

  As shown in FIG. 12, the wiping blade 600 of the first modification has suction ports 604 formed in two rows. That is, the adjacent suction ports 604 are provided so as to be shifted in a direction orthogonal to the row direction B (conveying direction A). Therefore, the suction port can be easily formed even if the distance S between the suction port 604 and the suction port 604 arranged in the row direction B is narrow. Note that the number of rows may be three or more.

  Next, a second modification will be described.

  As shown in FIG. 13, the wiping member 650 of Modification 2 is thick. The suction port 652 is provided far away from the transport direction A. The gap G between the suction port 652A and the suction port 652B in the transport direction A is wider than the length H of the nozzle row in the transport direction A.

  With such a configuration, after the scanning of the nozzle row C1 by the suction port 652A as in the wiping member 650 indicated by an imaginary line is completed, the next suction port 652B starts scanning of the next nozzle row C2. Therefore, only a specific nozzle 122 can be selectively sucked without using a machine groove such as a valve.

  In addition, this invention is not limited to the said embodiment.

  For example, in the above embodiment, the suction port covers one nozzle row when viewed in the direction orthogonal to the row direction, but the present invention is not limited to this. It does not have to straddle two nozzle rows. (For example, only half of one nozzle row may be covered).

  Further, for example, in the above-described embodiment, the wiping blade or the wiping member that cleans deposits such as ink droplets and dust adhering to the nozzle surface 32N individually sucks the nozzles 122, but is not limited thereto. In addition to the wiping blade and the wiping member, a sliding member that slides on the nozzle surface 32N may be provided for separate suction.

  Further, for example, in the above embodiment, as shown in FIG. 7, when the manifold 250 is a main flow, the common ink flow path 214 that is a branch flow branched from the manifold 250 communicates with each nozzle 122 (ejector 260). However, it is not limited to this. A structure (sea pool structure) in which each ejector is connected to a sea pool which is a large ink reservoir may be used.

  Further, for example, in the above embodiment, the wiping blade moves and wipes (slides) the nozzle surface. However, the present invention is not limited to this. The wiping blade may be fixed, and the ink jet recording head may move in the transport direction A (direction perpendicular to the row direction B). Alternatively, both the wiping blade and the ink jet recording head may move.

  Further, for example, in the above-described embodiment, the predetermined pattern for detecting defective ejection nozzles is formed on the recording paper P. However, the present invention is not limited to this. A predetermined pattern may be formed on the conveying belt 28 (see FIGS. 1 and 2) for conveying the recording paper P. In this case, in order to remove the predetermined pattern formed on the transport belt 28, it is necessary to provide the cleaning means 6 on the downstream side of the reading sensor 7 as shown by the dotted line in the figure.

  For example, in the above-described embodiment, the piezoelectric element 186 is used as the actuator that pressurizes the pressure chamber 170, but the present invention is not limited to this. (See FIG. 6). Another type of inkjet recording head may be used. In general, the piezoelectric inkjet recording head as in the above embodiment is more difficult to arrange the nozzles at a higher density than the thermal inkjet recording head. Therefore, as shown in FIG. 5, high resolution is achieved by arranging the nozzles 122 in a matrix form, and as shown in FIG. 9, one nozzle row is covered at the tip of the wiping blade (sliding member). Individual suction is realized by arranging a plurality of suction ports. That is, both high resolution and individual suction are realized.

  In the above-described embodiment, a long ink jet recording head having a width substantially equal to the width of the recording paper is provided, and the ink jet recording head is fixed and performs recording while transporting only the recording medium, so-called FWA (Full) Although it is an inkjet recording apparatus of a (Width Array) type, it is not limited to this. The ink jet recording head can also be applied to a so-called PWA (Partial Width Array) ink jet recording apparatus that performs printing while reciprocating in a direction orthogonal to the conveyance direction of the recording paper P. In this case, the row direction of the nozzle array is the same as the conveyance direction of the recording paper P. The direction in which the wiping blade (sliding member) slides is a direction orthogonal to the row direction, that is, a direction orthogonal to the transport direction. In this case, the wiping blade (sliding member) may move, the ink jet recording head may move, or both may move.

  The present invention is not limited to recording characters and images on the recording paper P. That is, the recording medium is not limited to the recording paper P, and the liquid to be discharged is not limited to ink. For example, ink droplets are ejected onto a polymer film or glass to create a color filter for display, or welded solder is ejected onto a substrate to form component mounting bumps. In addition, the present invention can be applied to all droplet discharge apparatuses.

  Further, it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

It is the schematic which shows the inkjet recording device of this invention in an image recording state. It is the schematic which shows the inkjet recording device of this invention in a maintenance state. FIG. 2 is a schematic diagram illustrating a conveyance belt and the vicinity thereof in the inkjet recording apparatus of the present invention. It is a perspective view which shows an inkjet recording head typically. (A) is a top view which shows the nozzle area | region of the head unit which comprises an inkjet recording head, (B) is a figure which shows typically the boundary part of the nozzle area | region of (A). (A) is a fragmentary sectional view which shows a head unit, (B) is an enlarged view of a nozzle part. It is a figure which shows the principal part inside a head unit typically in plan view. FIG. 4 is an enlarged view of a flow end portion of a common ink flow path. It is explanatory drawing which illustrates and illustrates typically a mode that a nozzle surface slides with a wiping blade. (A) is a side view schematically showing how the nozzle surface is slid with the wiping blade, and (B) is an enlarged view of the tip portion of the wiping blade. It is a figure which shows typically a wiping blade and a suction machine groove | channel. It is a side view which shows typically a mode that a nozzle surface is slid with the wiping blade of a 1st modification. It is a side view which shows typically a mode that a nozzle surface is slid with the wiping blade of a 2nd modification. It is a figure which shows typically the boundary part of a head unit. It is explanatory drawing explaining the wiping with the wiping blade in the conventional inkjet recording device.

Explanation of symbols

12 Inkjet recording head (droplet ejection device)
28 Conveying belt 32 Inkjet recording head (droplet ejection head)
32N Nozzle surface 122 Nozzle 123 Counterbore 500 Wiping blade A A recording medium transport direction (direction perpendicular to the row direction)
B Row direction C Column direction d Nozzle row spacing P Recording paper (recording medium)

Claims (11)

A liquid droplet ejection head having a nozzle surface on which nozzles arranged in a matrix are formed with a direction perpendicular to the row direction and an angle as a column direction.
A sliding member that slides the nozzle surface in a direction orthogonal to the row direction;
Provided side by side in the row direction at the end of the sliding member in contact with the nozzle surface, narrower than the row interval of the nozzles, and two nozzle rows when viewed in the direction perpendicular to the row direction A plurality of suction ports that cover a plurality of nozzles without straddling and can suck liquid from the nozzles;
A droplet discharge apparatus comprising:   2. The droplet discharge device according to claim 1, wherein the droplet discharge head includes a plurality of tributaries that are provided along a row direction of the nozzles and communicate with the plurality of nozzles.   3. The droplet discharge device according to claim 1, wherein the sliding member stops by moving at a row interval pitch of the nozzles and sucks liquid from the nozzles.   4. The droplet discharge device according to claim 1, wherein the adjacent suction ports are shifted in a direction perpendicular to the row direction. 5. It has a detecting means for detecting a discharge failure nozzle that has become a droplet discharge failure,
5. The liquid droplet ejection apparatus according to claim 1, wherein only the defective ejection nozzles detected by the detection unit are selectively sucked. 6. The detection means forms a predetermined pattern on the inspection discharge object by the droplets,
Read the predetermined pattern formed on the inspection object,
The droplet discharge device according to claim 5, wherein the discharge failure nozzle is detected.   The droplet discharge apparatus according to claim 6, wherein the inspection discharge target is a recording medium on which an image is formed by droplets.   7. The inspection object is a conveyance belt that is provided opposite to the nozzle surface of the droplet ejection head and conveys a recording medium on which an image is formed by droplets. The liquid droplet ejection apparatus described.   8. The liquid droplet ejection apparatus according to claim 1, wherein counterbore is formed around the nozzle of the liquid droplet ejection head. 9.   10. The droplet discharge device according to claim 1, wherein the sliding member also serves as a wiping blade for wiping the nozzle surface. 11. The row direction is a direction orthogonal to the transport direction of the recording medium on which an image is formed by droplets,
The droplet discharge area in the row direction of the droplet discharge head has a recording area width of the recording medium or more,
11. The liquid according to claim 1, wherein an image is formed by ejecting droplets onto the transported recording medium in a state where the droplet ejection head is fixed. Drop ejection device.

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