JP4872953B2 - Droplet discharge head and droplet discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make high in the density of electric wirings in a liquid droplet discharging head in which a plurality of piezoelectric bodies are arranged for one nozzle. <P>SOLUTION: One side 70A of each of the plurality of piezoelectric bodies 70 is electrically connected to a drive circuit 82 in common through the electric wring 72. Thus, the number of wirings connecting the piezoelectric body 70, and the drive circuits 82 and 83 is reduced to about 1/2 of that in constitution where they are all connected individually because it is the number of lines connected in common in addition to lines connected individually. Therefore, the high density of the electric wirings is contrived. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge device.

  As a droplet discharge head, an ink jet recording head disclosed in Patent Document 1 and Patent Document 2 is known. In the ink jet recording head disclosed in Patent Document 1 and Patent Document 2, two pressure chambers are arranged for one nozzle. Each of the pressure chambers is provided with a piezoelectric body that applies pressure to the ink filled in the pressure chamber.

  That is, the inkjet recording head disclosed in Patent Document 1 and Patent Document 2 is configured to have a plurality of pressure generating means for generating pressure for ejecting ink from each nozzle. ing.

According to this configuration, for example, the ejection direction of the ink droplets ejected from the nozzles can be changed by adjusting the pressure generated by the plurality of pressure generating units.
JP 54-131934 A JP 2004-358701 A

  Incidentally, in the ink jet recording head, as the nozzle density increases, the electrical wiring for transmitting an external signal to the pressure generating means also needs to be increased in density. As described above, in a configuration in which a plurality of pressure generating means are arranged for one nozzle, the number of pressure generating means doubles as the nozzle density increases, and the density of electrical wiring is particularly high. Necessary.

  An object of the present invention is to increase the density of electrical wiring in a droplet discharge head in which a plurality of pressure generating means are arranged for one nozzle.

  According to a first aspect of the present invention, a droplet discharge head includes a plurality of nozzles that discharge droplets, and a plurality of nozzles that are arranged for each of the plurality of nozzles, and generates pressure for discharging droplets from the nozzles. Pressure generating means, electrical wiring electrically connecting one of the plurality of pressure generating means disposed in one nozzle and one of the plurality of pressure generating means disposed in another nozzle, and the electrical wiring Connected to the driving means for steadily driving the pressure generating means regardless of the droplet ejection pattern, and the electric wiring so that the ejection direction of the droplets ejected from the nozzle is changed. And control means for controlling the other drive timing or drive energy level of the pressure generating means not connected to the pressure generating means.

  A droplet discharge head according to a second aspect of the present invention is the droplet discharge head according to the first aspect, wherein the nozzle discharges the droplet onto a transported recording medium, and the discharge direction is changed. Has a predetermined angle with the row direction orthogonal to the conveyance direction of the recording medium.

  According to a third aspect of the present invention, in the liquid droplet ejection head according to the first or second aspect, one of the plurality of pressure generating means arranged in one nozzle has a pressure chamber communicating with the nozzle through a passage. And the other of the plurality of pressure generating means arranged in the nozzle has a pressure chamber that communicates with the nozzle through a passage and is connected to the pressure chamber only through the passage.

  A droplet discharge head according to a fourth aspect of the present invention is the droplet discharge head according to any one of the first to third aspects, wherein a dot that is redirected and discharged from one nozzle is a dot that is discharged from another nozzle. It is characterized in that the discharge direction of the droplet is changed so as to be adjacent to each other.

  According to a fifth aspect of the present invention, in the configuration of any one of the first to fourth aspects, when the nozzle becomes an abnormal nozzle having an abnormal discharge characteristic, It is characterized in that the dots of the abnormal nozzles are complemented by changing the direction of the dots ejected from the adjacent nozzles.

  A droplet discharge head according to a sixth aspect of the present invention is characterized in that, in the configuration of the fifth aspect, the nozzles on both sides of the abnormal nozzle are used to complement the dots of the abnormal nozzle.

  According to a seventh aspect of the present invention, in the liquid droplet ejection head according to any one of the first to sixth aspects, the turning period is Tn, the number of turns is n, and the driving period for each row (direction) is T. When the natural period of the acoustic wave of the ejector is Tc, T> Tn * n and Tn> Tc.

A droplet discharge head according to an eighth aspect of the present invention includes a detection unit that detects a dot formation position of a dot formed by being discharged from a nozzle in the configuration according to any one of the first to seventh aspects,
When the dot formation position detected by the detection unit is different from the position where the dot should originally be, the control unit changes the dot discharged from the nozzle so that the dot landing position is close to the original position. It is characterized by facing.

  According to a ninth aspect of the present invention, there is provided a liquid droplet ejection apparatus that detects the dot formation position of the liquid droplet ejection head according to any one of the first to seventh aspects and a dot formed by ejection from a nozzle. And when the dot formation position detected by the detection means is different from the position where the dot should originally be, the landing position of the dot is close to the original position. As described above, the direction of the dots ejected from the nozzles is changed.

  According to the configuration of the first aspect of the present invention, the number of electrical wirings can be reduced and the density of the electrical wirings can be increased as compared with the case where the present configuration is not provided.

  According to the configuration of the second aspect of the present invention, as compared with the case where the configuration is not provided, the deviation of the dot conveyance direction is corrected by changing the ejection direction of the droplets ejected from the nozzle. can do.

  According to the configuration of the third aspect of the present invention, the ink is mixed between the connected pressure chambers as compared with the case where the present configuration is not provided, and therefore, between the pressure chambers generated by the increase in the viscosity of the ink. The difference in characteristics can be reduced.

  According to the configuration of the fourth aspect of the present invention, compared to the case where the configuration is not provided, the dots ejected by being redirected from one nozzle are adjacent to the dots ejected from the nozzle. Therefore, the interference can be suppressed.

  According to the configuration of the fifth aspect of the present invention, it is possible to suppress image quality deterioration due to the graininess of dots as compared with the case where the dot size is increased and the dots of the abnormal nozzles are complemented.

  According to the configuration of the sixth aspect of the present invention, the dots of the abnormal nozzle can be complemented more efficiently than when the configuration is not provided.

  According to the configuration of the seventh aspect of the present invention, the angle formed by the line formed by the droplets arranged in the direction of change and the line in the row direction can be reduced as compared with the case where the configuration is not provided.

  According to the configuration of the eighth aspect of the present invention, since the dot formation position can be corrected by detecting the dot formation position and changing the ejection direction, compared to the case where the configuration is not provided, the single ring is provided. Even without processing, the image quality in one pass can be improved.

  According to the configuration of the ninth aspect of the present invention, since the dot formation position can be corrected by detecting the dot formation position and changing the ejection direction, compared to the case where the configuration is not provided, the single ring is provided. Even without processing, the image quality in one pass can be improved.

Below, an example of an embodiment concerning the present invention is described based on a drawing.
[First Embodiment]
In this embodiment, as an example of a droplet discharge device that discharges droplets, an ink jet recording device that discharges ink droplets and records an image on a recording medium will be described.

  The droplet discharge device is not limited to the ink jet recording device. As a droplet discharge device, for example, a color filter manufacturing device for manufacturing a color filter by discharging ink or the like on a film or glass, a device for forming an EL display panel by discharging an organic EL solution onto a substrate, a dissolved state A device for forming a bump for mounting components by discharging a solder on a substrate, a device for forming a wiring pattern by discharging a liquid containing metal, and various film forming devices for forming a film by discharging a droplet It may be present as long as it ejects droplets.

(Overall configuration of inkjet recording apparatus according to this embodiment)
First, the overall configuration of the ink jet recording apparatus according to the present embodiment will be described. 1 and 2 schematically show the overall configuration of the ink jet recording apparatus according to the present embodiment.

  As shown in FIGS. 1 and 2, an inkjet recording apparatus 10 includes a recording medium storage unit 12 that stores a recording medium P such as paper, an image recording unit 14 that records an image on the recording medium P, and a recording medium storage. Conveying means 16 for transporting the recording medium P from the section 12 to the image recording section 14 and a recording medium discharging section 18 for discharging the recording medium P on which an image is recorded by the image recording section 14 are provided.

  The image recording unit 14 is an example of a droplet discharge head that discharges droplets, and inkjet recording heads 20Y, 20M, 20C, and 20K (hereinafter referred to as 20Y to 20K) that discharge ink droplets and record an image on a recording medium. ).

  The inkjet recording heads 20Y to 20K are arranged in parallel in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side in the conveyance direction of the recording medium P. The ink droplets corresponding to the respective colors are ejected from a plurality of nozzles formed on the nozzle surface by a piezoelectric method, and an image is recorded. In the inkjet recording heads 20Y to 20K, the configuration for ejecting ink droplets may be a configuration for ejecting ink droplets by other methods such as a thermal method.

  Further, the ink jet recording heads 20Y to 20K are configured to be longer in the width direction (main scanning direction) of the recording medium P than the conveyance direction (sub scanning direction) of the recording medium P. The inkjet recording heads 20Y to 20K can form one line in the main scanning direction without moving relative to the recording medium P in the main scanning direction, and move relative to the recording medium P in the sub scanning direction. Thus, color images are recorded. The width direction of the recording medium P is a direction that intersects with the conveyance direction of the recording medium P.

  The ink jet recording apparatus 10 is provided with ink tanks 21Y, 21M, 21C, and 21K (hereinafter referred to as 21Y to 21K) that store ink as liquid storage units that store liquid. Ink is supplied from the ink tanks 21Y to 21K to the inkjet recording heads 20Y to 20K. As the ink supplied to the inkjet recording heads 20Y to 20K, various inks such as water-based ink, oil-based ink, and solvent-based ink can be used.

  Furthermore, the inkjet recording apparatus 10 is provided with maintenance units 22Y, 22M, 22C, and 22K (hereinafter referred to as 22Y to 22K) that perform maintenance of the inkjet recording heads 20Y to 20K. The maintenance units 22Y to 22K are respectively opposed to the nozzle surfaces of the ink jet recording heads 20Y to 20K (see FIG. 2) and retracted from the nozzle surfaces of the ink jet recording heads 20Y to 20K (see FIG. 1). It is configured to be movable between.

  Each of the maintenance units 22Y to 22K includes a cap that covers the nozzle surfaces of the ink jet recording heads 20Y to 20K, a receiving member that receives preliminarily ejected (empty ejected) liquid droplets, and a cleaning member that cleans the nozzle surfaces of the ink jet recording heads 20Y to 20K. When the ink jet recording heads 20Y to 20K are maintained, the ink jet recording heads 20Y to 20K are raised by a predetermined height and the maintenance unit 22Y is provided. ˜22K moves to the opposite position and performs various maintenance.

  The transport unit 16 includes a feed roll 24 that sends out the recording medium P accommodated in the recording medium storage unit 12, a transport roll pair 25 that sandwiches and transports the recording medium P sent out by the feed roll 24, and a transport roll pair 25. And an endless conveyance belt 30 that causes the recording surface of the recording medium P conveyed by the inkjet recording heads 20Y to 20K to face each other.

  The conveyance belt 30 is wound around a driving roll 26 disposed on the downstream side in the conveyance direction of the recording medium P and a driven roll 28 disposed on the upstream side in the conveyance direction of the recording medium P, and is wound in a predetermined direction (A in FIG. 1). Direction).

  The transport belt 30 may be a transport body that transports the recording medium P. For example, a transport drum as an example of a transport body that transports the recording medium P on the outer peripheral surface may be used.

  In addition, a pressing roll 27 that presses the recording medium P against the conveyance belt 30 is provided above the driven roll 28. The pressing roll 27 is driven by the conveying belt 30 and also serves as a charging roll. When the conveying belt 30 is charged by the pressing roll 27, the recording medium P is electrostatically attracted to the conveying belt 30 and conveyed. It is a configuration.

  When the conveyance belt 30 conveys the recording medium P, the inkjet recording heads 20Y to 20K and the recording medium P move relative to each other, and ink droplets are ejected onto the relatively moving recording medium P to form an image.

  Note that the inkjet recording heads 20Y to 20K may move with respect to the recording medium P, and the recording medium P and the inkjet recording heads 20Y to 20K may be configured to move relative to each other.

  Further, the conveyance belt 30 is not limited to a configuration that holds the recording medium P by electrostatic adsorption, but is a non-electrostatic means such as friction with the recording medium P or suction or adhesion of the recording medium P. It may be configured to be held by.

  A separation claw for separating the recording medium P from the conveyance belt 30 is disposed on the downstream side of the conveyance belt 30 so as to be able to approach and separate. The recording medium P on which an image is recorded by the ink jet recording heads 20Y to 20K is configured such that the recording medium P is peeled off from the transport belt 30 by the curvature of the transport belt 30 and the peeling claw. In addition, in FIG.1 and FIG.2, illustration of the peeling nail | claw is abbreviate | omitted.

  On the downstream side of the peeling claw, a plurality of transport roll pairs 29 in which the recording surface side of the recording medium P is a star wheel are provided. The recording medium P on which an image is recorded by the image recording unit 14 is conveyed to the recording medium discharge unit 18 by the conveyance roll pair 29.

  A reversing unit 37 that reverses the recording medium P is provided below the conveyance belt 30. After the conveyance roll pair 29 once conveys the recording medium P downstream, the conveyance roll pair 29 reverses and records. The medium P is sent to the reversing unit 37.

  The reversing unit 37 is provided with a plurality of conveying roll pairs 23 in which the recording surface side of the recording medium P is a star wheel, so that the recording medium P sent to the reversing unit 37 is sent to the conveying belt 30 again. It has become.

  In addition, although not shown, the inkjet recording apparatus 10 performs the overall operation of the inkjet recording apparatus 10 and the ejection timing of ink droplets, the head controller that determines the nozzles of the inkjet recording heads 20Y to 20K to be used, and the inkjet recording apparatus 10. System control means for controlling.

  Next, an image recording operation of the inkjet recording apparatus 10 will be described.

  First, the recording medium P is sent out from the recording medium container 12 by the sending roll 24, and sent to the transport belt 30 by the transport roll pair 25 on the upstream side of the transport belt 30.

  The recording medium P sent to the conveying belt 30 is attracted and held on the conveying surface of the conveying belt 30 and conveyed to the recording positions of the ink jet recording heads 20Y to 20K, and an image is recorded on the recording surface of the recording medium P. The Then, after the image recording is finished, the recording medium P is peeled off from the transport belt 30 by a peeling claw.

  When an image is recorded only on one side of the recording medium P, it is discharged to the recording medium discharge unit 18 by a pair of conveying rolls 29 on the downstream side of the conveying belt 30.

  When recording an image on both sides of the recording medium P, after the image is recorded on one side, the recording medium P is reversed by the reversing unit 37 and sent to the transport belt 30 again. Images are recorded on the opposite side of the recording medium P in the same manner as described above, images are recorded on both sides of the recording medium P, and are discharged to the recording medium discharge unit 18.

(Configuration of inkjet recording heads 20Y to 20K according to the present embodiment)
Next, the configuration of the inkjet recording heads 20Y to 20K according to the present embodiment will be described. Here, the inkjet recording head 20Y will be described. The other ink jet recording heads 20M to 20K are configured similarly. FIG. 3 is a schematic cross-sectional view showing the configuration of the ink jet recording head according to the present embodiment, with its main portion extracted. FIG. 4 is a schematic diagram schematically showing the configuration of the ink jet recording head according to the present embodiment.

  As shown in FIG. 4, the ink jet recording head 20 </ b> Y according to the present embodiment includes a plurality of nozzles 52 that eject ink droplets. Two pressure chambers 56 are arranged for each of the plurality of nozzles 52. The two pressure chambers 56 communicate with one nozzle 52, and ink can flow from the two pressure chambers 56 to one nozzle 52.

  On each pressure chamber 56, a piezoelectric body 70 as an example of a pressure generating unit that generates a pressure for ejecting ink droplets from the nozzle 52 is disposed.

  As described above, in this embodiment, the ejector 53 as the minimum unit of the configuration for ejecting ink droplets is arranged on one nozzle 52, two pressure chambers 56 communicating with the nozzle 52, and the pressure chamber 56. A total of two piezoelectric bodies 70 are included.

  Note that a configuration in which three or more pressure chambers 56 and piezoelectric bodies 70 are arranged for one nozzle 52 may be employed.

  Further, as a method for ejecting ink, a thermal method in which ink is boiled by heat generation and ink is ejected by the pressure of bubbles generated at that time may be used. Used.

  Specifically, as shown in FIG. 3, the inkjet recording head 20 </ b> Y according to the present embodiment includes a recess forming plate 40, a nozzle plate 42, a pressure chamber forming plate 44, a common supply path forming plate 46, and a supply path forming plate 48. A plurality of plates 50 including the vibration plate 68 and the piezoelectric body 70 are laminated.

  A nozzle 52 is formed on the nozzle plate 42. A recess 54 is formed on the periphery of the nozzle 52 in the recess forming plate 40. The concave portion 54 is a step formed at the peripheral edge of the nozzle 52, and the periphery of the nozzle 52, for example, is caused by friction caused by contact with the recording medium P by retreating the portion where the nozzle 52 is formed from the surrounding plate surface. This prevents mechanical friction due to wiping of the nozzle surface.

  Two pressure chambers 56 communicating with the nozzles 52 and filled with ink are formed in the pressure chamber forming plate 44. Each of the pressure chambers 56 communicates with the nozzle 52 via a passage 58 so that ink can flow from the pressure chamber 56 to the nozzle 52. A passage 58 communicating with the two pressure chambers 56 is connected between the pressure chamber 56 and the nozzle 52 in the vicinity of the nozzle 52.

  As shown in FIG. 3, each pressure chamber 56 is formed separately in the pressure chamber forming plate 44 and is connected only through the passage 58, but as shown in FIG. The pressure chamber 56 may be configured to communicate with the pressure chamber forming plate 44.

  In the common supply path forming plate 46, two common supply paths 60 are formed corresponding to the two pressure chambers 56, and the common supply path 60 is provided for each of the pressure chambers 56. A supply path 62 for supplying ink from the common supply path 60 to the pressure chamber 56 is formed in the supply path forming plate 48.

  Further, the supply path 62 communicates with the common supply path 60 through the first supply hole 64. Further, the supply path 62 communicates with the pressure chamber 56 via the second supply hole 66. Accordingly, the ink supplied to the common supply path 60 is filled in each pressure chamber 56 through the first supply hole 64, the supply path 62, and the second supply hole 66.

  The diaphragm 68 formed on the pressure chamber forming plate 44 constitutes a part of the pressure chamber 56 by closing the upper opening of the pressure chamber 56 and forming the upper wall of the pressure chamber 56.

  As shown in FIG. 4, the piezoelectric body 70 laminated on the vibration plate 68 is connected to electrical wirings 72 and 73 for inputting a drive signal to the piezoelectric body 70, and is driven by acquiring an electrical signal as a drive signal. It is supposed to be.

  The piezoelectric body 70 acquires an electrical signal, displaces the vibration plate 68 so as to reduce the volume in the pressure chamber 56, and generates pressure on the ink in the pressure chamber 56. Thus, ink is sent from the pressure chamber 56 to the nozzle 52 via the passage 58, and ink droplets are ejected from the nozzle 52.

  Specifically, one of the two piezoelectric bodies 70 arranged for each nozzle 52 is electrically connected to the electric wiring 72 and connected to a driving circuit 82 as an example of a driving unit. One of the plurality of piezoelectric bodies 70 </ b> A is electrically connected in common to the drive circuit 82 by the electric wiring 72.

  The other 70 </ b> B of the piezoelectric body 70 is individually connected to the electric wiring 73 and is connected to a drive circuit 83 as an example of a control unit.

  The drive circuit 82 is configured to constantly drive one 70A of the piezoelectric body 70 regardless of the droplet ejection pattern. At this time, for example, the waveform B shown in FIG. 5 is applied.

  The drive circuit 83 selectively inputs a drive waveform in accordance with the droplet ejection pattern and drives the other 70B of the piezoelectric body 70. At this time, for example, the waveform A shown in FIG. 5 is applied.

  The waveform A and the waveform B have different application timings, and the drive timings of the one 70A and the other 70B of the piezoelectric body 70 are shifted, so the ejection direction of the ink droplets ejected from the nozzles 52 is changed. The ejection direction of the ink droplets ejected from the nozzles 52 may be changed by changing the driving energy of the one 70A and the other 70B of the piezoelectric body 70.

  Here, the ink droplet ejection direction is changed along the direction of the passage 58 coupled between the pressure chamber 56 and the nozzle 52.

  In the present embodiment, the passage 58 coupled between the pressure chamber 56 and the nozzle 52 is formed at a predetermined angle with respect to the row direction orthogonal to the conveyance direction of the recording medium P, as shown in FIG. ing. Thereby, the ejection direction of the ink droplet is changed by being inclined by a predetermined angle with respect to the row direction.

  The combined passage 58 may be formed along the row direction.

(Operation of this embodiment)
Next, the operation of the above embodiment will be described.

  According to the ink jet recording head 20Y according to the present embodiment, one of the plurality of piezoelectric bodies 70 electrically connected in common to the drive circuit 82 by the electric wiring 72 is steadily driven regardless of the droplet ejection pattern. To do. At this time, for example, a waveform B shown in FIG. 5 is applied to the one 70 </ b> A of the piezoelectric body 70.

  A drive waveform is selectively input to the other 70B of the plurality of piezoelectric bodies 70 individually electrically connected to the drive circuit 83 by the electrical wiring 73 according to the droplet ejection pattern. At this time, for example, a waveform A shown in FIG. 5 is applied to the other 70 </ b> B of the piezoelectric body 70.

  The waveform A and the waveform B have different application timings, whereby the ejection direction of the ink droplet ejected from the nozzle 52 is changed.

  In the present embodiment, the number of wires connecting the piezoelectric body 70 and the drive circuits 82 and 83 is a common connected line in addition to the individually connected lines. As a result, the number of wirings is reduced to about ½. As a result, the density of the electrical wiring can be increased, and the pitch of the electrical wiring can be increased, so that the wiring cost can be reduced. Further, since the number of individually driven piezoelectric bodies is about ½, the number of drive circuits is also about ½, and the cost of the electric circuit system can be reduced.

  Furthermore, in this embodiment, since the direction is changed by tilting by a predetermined angle with respect to the row direction, as shown in FIG. 8A, the todd discharged from the nozzle 52 is displaced along the transport direction. However, as shown in FIG. 8B, it is possible to correct the deviation in the dot conveyance direction. FIG. 8A shows a case where the dots forming the row (2) are shifted to the upstream side in the transport direction with respect to the dots forming the row (1). FIG. 8B shows a case where the dots forming the row (2) are not displaced in the transport direction with respect to the dots forming the row (1).

[Second Embodiment]
Next, a second embodiment will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted. Further, the overall configuration of the image forming apparatus and the basic configuration of the ink jet recording head are the same as those in the first embodiment, and thus the description thereof is omitted.

  In the inkjet recording head 100 according to the second embodiment, as shown in FIG. 9, the nozzles 52 are arranged in a matrix (two-dimensional), and adjacent dots adjacent in the row direction are not formed by the same nozzle 52. In addition, the ejection direction of the ink droplets is changed by the drive circuit 83. In this configuration, the dots ejected from the nozzles 52 are skipped in the row direction to form a dot row, and are adjacent to only the dots ejected from the other nozzles.

Specifically, a dot row is formed as follows. That is, the dots ejected from the nozzle 52A arranged at the leftmost in FIG. 9 form the leftmost dot row and the third dot row from the left in FIG. The dots ejected from the nozzle 52B arranged second from the left in FIG. 9 form the second dot row from the left and the fourth dot row from the left in FIG. The dots ejected from the nozzle 52C arranged third from the left in FIG. 9 form the fifth dot row from the left and the seventh dot row from the left in FIG. The dots ejected from the nozzle 52D arranged fourth from the left in FIG. 9 form the sixth dot row from the left and the eighth dot row from the left in FIG.
In FIG. 9, the dots ejected from the nozzle 52E arranged fifth from the left form the ninth dot row from the left and the eleventh dot row from the left in FIG. In FIG. 9, the dots ejected from the nozzle 52F arranged sixth from the left form the tenth dot row from the left and the twelfth dot row from the left in FIG.

  In this way, by changing the ink droplet ejection direction so that adjacent dots are not formed by the same nozzle 52, interference between adjacent dots can be suppressed.

[Third Embodiment]
Next, a third embodiment will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted. Further, the overall configuration of the image forming apparatus and the basic configuration of the ink jet recording head are the same as those in the first embodiment, and thus the description thereof is omitted.

  In the inkjet recording head 200 according to the third embodiment, as shown in FIG. 10B, when the nozzle 52 becomes an abnormal nozzle having an abnormal discharge characteristic, for example, the nozzle 52 is in a non-discharge state. In this case, the nozzle 52 that discharges a dot adjacent to the dot to be discharged from the nozzle 52 is used to complement the dot to be discharged.

  In this configuration, the ink droplets formed by the continuous nozzle drive by the nozzles 52 to be complemented are changed by the drive circuit 83 so that the dots to be ejected from the nozzles 52 in the non-ejection state are complemented. .

  As shown in FIG. 10C, when the two adjacent nozzles 52 are in a non-ejection state, the normal nozzle 52 adjacent to one of the nozzles 52 in the non-ejection state and the non-ejection state A normal nozzle 52 adjacent to the other of the nozzles 52 that has become may be used to supplement the dots to be ejected.

  10A shows a state where ink droplets are normally ejected from the nozzle 52, and FIG. 10B shows a case where the second nozzle 52 from the left in the figure is in a non-ejection state. FIG. 10C shows a configuration in which dots are complemented by the first nozzle 52 from the left in the drawing, and FIG. 10C shows the case where the second and third nozzles 52 from the left in the drawing are in a non-ejection state. A configuration is shown in which discharge is complemented from the second nozzle 52 from the left by the first nozzle 52 from the left in the figure, and discharge complementation is from the third nozzle 52 from the left by the fourth nozzle 52 from the left in the figure. ing.

  In this configuration, since the dots of the nozzles in the non-ejection state can be supplemented by continuous driving, the image quality can be maintained without reducing the driving frequency and without reducing the recording speed.

  Further, since the dot size is not increased and the dot is complemented as shown in FIGS. 11A and 11B, image quality degradation due to the graininess of the ink droplets can be improved.

[Fourth Embodiment]
Next, a fourth embodiment will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted. Further, the overall configuration of the image forming apparatus and the basic configuration of the ink jet recording head are the same as those in the first embodiment, and thus the description thereof is omitted.

  As shown in FIGS. 12A and 12B, the ink jet recording head 300 according to the fourth embodiment includes detection means 80 that detects the dot formation position of the dots formed by being ejected from the nozzles 52.

  For example, the detection unit 80 may be configured to detect a dot formation position by analyzing an image captured by a camera using a camera that captures a recorded dot image. The detection unit 80 may be provided in a component other than the ink jet recording head 20Y of the ink jet recording apparatus 10.

  In this configuration, when the dot formation position detected by the detection means 80 is different from the position where the dot should originally be, the drive circuit 83 adjusts the dot formation position by changing the ejection direction. .

  According to this configuration, since the dot formation position is corrected by detecting the dot formation position and changing the ejection direction, the image quality in one pass can be improved without the shingling process. As a result, the recording speed can be improved without degrading the image quality.

  As shown in FIGS. 13 and 14, the dot forming position of the detecting means 80 can be detected even in a configuration in which pixels of two lines (columns) or more are formed by changing the ejection direction by using one nozzle 52. Depending on the detection result, the dot formation position can be adjusted by changing the ejection direction.

  As shown in FIG. 13A, when the dot formation position is deviated from the original position, the dot formation position is changed by changing the ejection direction as shown in FIG. to correct.

  As shown in FIG. 14A, when there is a non-ejection state nozzle 52, there are positions where dots are not formed. As shown in FIG. 14B, the non-ejection state nozzle 52 is located on both sides. By changing the discharge direction of the adjacent nozzles 52, the dots are complemented.

[Fifth Embodiment]
Next, a fifth embodiment will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted. Further, the overall configuration of the image forming apparatus and the basic configuration of the ink jet recording head are the same as those in the first embodiment, and thus the description thereof is omitted.

  In the configuration of the fifth embodiment, the turning period is Tn, the number of turns is n, the driving period for each row (direction) is T, and the natural period of the acoustic wave (helmholtz vibration period) in the ejector 53 is Tc. In this case, T> Tn * n and Tn> Tc (T / n> Tn> Tc).

  A time longer than Tc is required until the ejected ink (column) and the meniscus surface are separated. When Tn is set to a value smaller than Tc, if the next ejection is applied before the ink column is divided from the meniscus surface, the ejection direction is changed by being drawn by the previous droplet. Also, depending on the conditions of subsequent ejection, it is absorbed by the previous droplet and becomes one droplet. By setting Tn> Tc, it is possible to fly continuously driven droplets separately.

  The turning period Tn is the driving period of each dot to be redirected, and appears as a shift along the transport direction between the formed dots, as shown in FIGS.

  The drive cycle T for each row (direction) appears as a shift along the transport direction for each column in the row direction of the formed dots, as shown in FIGS.

  15 and 16 show examples of dot formation when the dots ejected from the nozzle 52 are changed in four directions, that is, an example where n = 4.

  In the example shown in FIG. 15, it is a case where T = Tn * n, and FIG. 16 is a case where T> Tn * n.

  As shown in FIG. 16, in the case of T> Tn * n as shown in FIG. 15, the line formed in the direction of change and the line direction (in the row direction) are formed. The angle (θ) formed by the line in the direction perpendicular to the paper conveyance direction can be reduced, and the horizontal line can be made as straight as possible.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

FIG. 1 is a schematic diagram illustrating the overall configuration of the ink jet recording apparatus according to the first embodiment. FIG. 2 is a schematic diagram illustrating a state in which the maintenance unit is in a facing position facing the nozzle surface of the ink jet recording head in the ink jet recording apparatus according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing the configuration of the ink jet recording head according to the first embodiment with its main part extracted. FIG. 4 is a schematic view schematically showing the configuration of the ink jet recording head according to the first embodiment. FIG. 5 is a diagram illustrating a waveform of a drive signal input to the piezoelectric body according to the first embodiment. FIG. 6 is a schematic cross-sectional view showing a modification in which the pressure chamber according to the first embodiment communicates within the pressure chamber forming plate. FIG. 7 is a diagram illustrating a configuration in which a passage coupled between the pressure chamber and the nozzle according to the first embodiment is formed at a predetermined angle with respect to the row direction. FIG. 8A shows a case where one dot row is shifted to the upstream side in the transport direction with respect to the other dot row, and FIG. 8B shows one dot row with respect to the other dot row. It is a figure which shows the case where it has not shifted | deviated to the conveyance direction. FIG. 9 is a diagram for explaining a configuration according to the second embodiment. FIG. 10 is a diagram for explaining a configuration according to the third embodiment. FIG. 11 is a diagram illustrating a comparative example in which the dot size is increased to complement the dots. FIG. 12 is a diagram for explaining a configuration according to the fourth embodiment. FIG. 13 is a diagram for explaining a configuration in which pixels of two lines (columns) or more are formed by changing the ejection direction with one nozzle in the configuration according to the fourth embodiment. FIG. 14 is a diagram for describing a configuration in which pixels of two lines (columns) or more are formed by changing the ejection direction with one nozzle 52 in the configuration according to the fourth embodiment. FIG. 15 is a diagram for explaining a configuration according to the fifth embodiment. FIG. 16 is a diagram for explaining a configuration according to the fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet recording apparatus 20Y-20K Inkjet recording head 52 Nozzle 56 Pressure chamber 58 Passage 70 Piezoelectric body (pressure generating means)
72 Electrical wiring 73 Electrical wiring 80 Detection means 82 Drive circuit (drive means)
83 Drive circuit (control means)
100 Inkjet recording head 200 Inkjet recording head 300 Inkjet recording head

Claims (9)

A plurality of nozzles for discharging droplets;
A plurality of pressure generating means which are arranged for each of the plurality of nozzles and generate pressure for discharging droplets from the nozzle;
An electrical wiring for electrically connecting one of the pressure generating means arranged in one nozzle and one of the pressure generating means arranged in another nozzle;
Driving means connected to the electrical wiring and driving the one of the pressure generating means to such an extent that droplets are not ejected from the nozzles steadily regardless of the droplet ejection pattern;
The other drive timing of the pressure generating means not connected to the electric wiring is controlled so that the discharge direction of the droplet from the nozzle is changed according to the droplet ejection pattern. Control means to
A liquid droplet ejection head comprising: The nozzle discharges droplets onto a recording medium to be conveyed,
2. The liquid droplet ejection head according to claim 1, wherein the direction in which the liquid ejection direction is changed has a predetermined angle with a row direction orthogonal to the recording medium conveyance direction. . One of the plurality of pressure generating means arranged in one nozzle has a pressure chamber communicating with the nozzle through a passage,
The other of the pressure generating means arranged in the nozzle has a pressure chamber that communicates with the nozzle through a passage and is connected to the pressure chamber only through the passage. The droplet discharge head described.   4. The liquid droplet ejection direction is changed so that a dot redirected and discharged from one nozzle is adjacent to only a dot ejected from another nozzle. The droplet discharge head according to any one of the above.   When the nozzle becomes an abnormal nozzle having an abnormal discharge characteristic, the dots of the abnormal nozzle are complemented by changing the direction of the dots discharged from the nozzle adjacent to the abnormal nozzle. The droplet discharge head according to claim 1.   The droplet discharge head according to claim 5, wherein the nozzles on both sides of the abnormal nozzle are used for complementing the dots of the abnormal nozzle.   T> Tn * n and Tn> Tc, where Tn is the turning period, n is the number of turns, T is the driving period for each row (direction), and Tc is the natural period of the acoustic wave of the ejector. The liquid droplet ejection head according to claim 1, wherein Comprising a detecting means for detecting a dot forming position of a dot formed by being ejected from a nozzle;
When the dot formation position detected by the detection unit is different from the position where the dot should originally be, the control unit changes the dot discharged from the nozzle so that the dot landing position is close to the original position. The liquid droplet ejection head according to claim 1, wherein the liquid droplet ejection head is oriented. A droplet discharge head according to any one of claims 1 to 7,
Detection means for detecting the dot formation position of the dots formed by ejection from the nozzle;
With
The control means of the liquid droplet ejection head is arranged so that when the dot formation position detected by the detection means is different from the position where the dot should originally be, the dot landing position is close to the original position. A droplet discharge device that changes the direction of discharged dots.

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