JP5306010B2 - Droplet discharge head and image forming apparatus - Google Patents

Description

  The present invention relates to a droplet discharge head and an image forming apparatus.

  Conventionally, in a configuration in which pressure is generated in a pressure chamber to pressurize liquid and discharged as droplets from a discharge port, the pressure flows back to the liquid flow path that supplies the liquid to each pressure chamber, and discharge in other pressure chambers There was a so-called crosstalk problem that affected performance.

  In contrast, for example, an inkjet recording apparatus has been proposed in which a piezoelectric member for reducing crosstalk is provided independently of a piezoelectric member that generates pressure for ejection.

  For example, the pressure generated in each pressure chamber for discharging ink is transmitted to other pressure chambers through the common liquid chamber, and the meniscus (liquid level) A configuration of an ink jet printer that reduces the crosstalk by attaching a correcting piezoelectric member that performs control of () is disclosed (for example, see Patent Document 1).

  In addition, in order to cancel out the crosstalk caused by the first actuator that performs discharge, the second actuator is provided in the common liquid chamber, and in particular, the configuration of the ink jet printer provided with the second actuator corresponding to each pressure chamber. Is disclosed (for example, see Patent Document 2).

JP-A-10-119260 JP 2004-106217 A

  However, since the method described in Patent Document 1 requires a driving circuit and wiring dedicated to the correcting piezoelectric member, the structure is complicated, and there is a risk of yield reduction and cost increase. In addition, since the amount of crosstalk varies depending on the number of pressure chambers that are driven simultaneously, it is necessary to count the number of pressure chambers that are driven simultaneously with a counter, and to add a displacement proportional to this to the correcting piezoelectric member. Requires a lot of control.

  In addition, it is necessary to provide a dedicated drive circuit and wiring for the correcting piezoelectric member, which may hinder high-density mounting of the discharging piezoelectric member, which is not desirable for increasing the nozzle arrangement density.

  Further, the configuration described in Patent Document 2 also requires a dedicated drive circuit and wiring for driving the second actuator, and cannot be avoided from complicated structure and increased cost. Further, it is the same as in Patent Document 1 that there is a possibility of hindering the high density of the nozzle arrangement.

  In view of the above-described facts, it is an object of the present invention to provide a droplet discharge head and an image forming apparatus provided with a crosstalk correcting pressure generating means that does not require a dedicated driving circuit and driving wiring.

The invention according to claim 1 is a liquid supply channel through which a liquid is supplied, a plurality of pressure chambers that communicate with the liquid supply channel and pressurize the liquid, and a nozzle that communicates with the pressure chamber and discharges droplets And a first pressure generating means that is provided for each pressure chamber and pressurizes the pressure chamber, and a back surface of the surface on the supply path through which the liquid of a member constituting one wall of the liquid supply channel flows. A drive wiring provided for each of the first pressure generating means and transmitting an electric signal to each of the first pressure generating means; and provided on the drive wiring outside the wall surface of the liquid supply flow path. Second pressure generating means for displacing the one surface of the liquid supply channel in the opposite phase when the same driving voltage as that of the pressure generating means is applied, and the first pressure generating means and the second pressure generating means One of the pressure generating means is connected to the drive wiring by a solid electrode, and the other is changed. The range is characterized in that it is connected with a donut-shaped electrode surrounded by a closed curve.

According to the above invention, the pressure applied by the first pressure generating means to the pressure chamber is canceled by generating a pressure in the opposite phase to the inside of the liquid supply flow path, thereby improving the crosstalk. By providing the second pressure generating means for generating the phase pressure in the drive wiring for driving the first pressure generating means, a simple configuration that does not require a dedicated circuit / wiring can be achieved. In addition, since the driving directions of the first pressure generating means and the second pressure generating means can be set opposite to each other only by the shape of the electrodes, the manufacturing process and the like can be simplified.

  The invention described in claim 2 is characterized in that the first pressure generating means and the second pressure generating means are piezoelectric bodies.

  According to the above invention, by using the piezoelectric body as the pressure generating means, the manufacturing process can be simplified and the manufacturing cost can be reduced.

  According to a third aspect of the present invention, a part of the drive wiring contacts the piezoelectric body on the one surface of the liquid supply flow path to form the second pressure generating means.

  According to said invention, it can be set as a simple structure by providing the piezoelectric body which contacts a part of drive wiring provided in the wall surface of the liquid supply flow path, and setting it as a 2nd pressure generation means.

According to a fourth aspect of the present invention, the first pressure generating means and the second pressure generating means are both solid electrodes or connected to the drive wiring by a donut-shaped electrode surrounded by a closed curve in a range to be displaced. The first pressure generating means and the second pressure generating means have polarization directions opposite to each other.

  According to the above invention, even if the first pressure generation means and the second pressure generation means are electrodes having the same shape, the drive directions of the both can be set opposite to each other, so that the limit of the mounting density can be increased.

According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, the ratio of the second pressure generating means provided in the drive wiring is the ratio of the liquid supply flow path. It is characterized by being higher at a location near the center in the longitudinal direction than at a location near the end in the longitudinal direction of the liquid supply channel.

  According to the above invention, in the vicinity of the central portion in the longitudinal direction that is most susceptible to crosstalk and has a large number of adjacent pressure chambers, more second pressure generating means than the end portions are provided efficiently. The influence of crosstalk can be suppressed.

According to a sixth aspect of the present invention, in the configuration according to any one of the first to fifth aspects, the second pressure generating means is operated as a vibration detector, so that The natural vibration in the liquid is detected, and the first pressure generating means connected to the drive wiring not provided with the second pressure generating means is displaced in a direction to cancel the natural vibration.

  According to the above invention, the natural vibration in the liquid supply path generated by the crosstalk is detected by using the second pressure generating means as a sensor, and the other first pressure generating means is driven at the timing to cancel the natural vibration. By doing so, the influence of crosstalk can be suppressed efficiently.

According to a seventh aspect of the present invention, in the configuration according to any one of the first to fourth aspects, the second pressure generating means is provided for each of the drive wirings.

  According to the above invention, since the crosstalk generated for each driven first pressure generating means is canceled by the second pressure generating means each time, the influence of the crosstalk can be suppressed more strongly. .

The invention according to claim 8 is the configuration according to any one of claims 2 to 7 , wherein the first pressure generating means and the second pressure generating means separate one piezoelectric body. It is characterized by being formed . According to the above invention, by dividing one piezoelectric body into the first pressure generating means and the second pressure generating means, the manufacturing process can be simplified and the manufacturing cost can be reduced.

The invention according to claim 9, characterized by comprising the liquid droplet ejection head according to any one of claims 1 to 8.

  According to the above invention, it is possible to provide an image forming apparatus including a crosstalk correcting pressure generating unit that does not require a dedicated driving circuit and driving wiring.

  Since the present invention has the above-described configuration, it is possible to provide a droplet discharge head and an image forming apparatus provided with a crosstalk correction pressure generating unit that does not require a dedicated drive circuit and drive wiring.

1 is a conceptual diagram illustrating a main part of an image forming apparatus according to an embodiment of the present invention. It is a side view which expands and shows the structure of the head plate used for the inkjet line head which concerns on embodiment of this invention. It is a figure which expands and shows the structure of the piezoelectric material for discharge shown in FIG. It is a figure which expands and shows the structure of the piezoelectric material for correction | amendment shown in FIG.

  Hereinafter, an exemplary embodiment according to the present invention will be described with reference to the drawings.

<Overall configuration>
As shown in FIG. 1, the image forming apparatus 10 according to the present embodiment is provided with a paper feed conveyance unit 12 that feeds and conveys paper P on the upstream side in the conveyance direction of the paper P as a recording medium. An image is formed on the recording surface of the paper P on the recording surface of the paper P, and on the downstream side in the transport direction of the paper feeding / conveying unit 12, along the transport direction of the paper P An image forming unit 16, an image fixing unit 20 that fixes the dried image on the paper P, and a discharge unit 21 that discharges the paper P on which the image is fixed are sequentially provided. Hereinafter, each processing unit will be described.

<Paper feed section>
The paper feeding / conveying unit 12 is provided with a stacking unit 22 on which the sheets P are stacked, and the sheets P stacked on the stacking unit 22 are fed one by one downstream of the stacking unit 22 in the sheet conveying direction. A paper feeding unit 24 is provided. The paper P fed by the paper feeding unit 24 is transported to the processing liquid coating unit 14 via a transport unit 28 constituted by a plurality of roller pairs 26.

<Processing liquid application part>
In the treatment liquid application unit 14, a treatment liquid application drum 30 is rotatably disposed. The processing liquid coating drum 30 is provided with a holding member 32 that holds the paper P by sandwiching the leading end of the paper P, and the paper P is placed on the surface of the processing liquid coating drum 30 via the holding member 32. In the held state, the sheet P is conveyed downstream by the rotation of the treatment liquid coating drum 30.

  Note that an intermediate conveying drum 34, an image forming drum 36, and an image fixing drum 40, which will be described later, are also provided with a holding member 32 in the same manner as the processing liquid coating drum 30. The holding member 32 delivers the paper P from the upstream drum to the downstream drum.

  A processing liquid coating device 42 and a processing liquid drying device 44 are disposed on the upper portion of the processing liquid coating drum 30 along the circumferential direction of the processing liquid coating drum 30. The treatment liquid is applied to the recording surface, and the treatment liquid is dried by the treatment liquid drying device 44.

  Here, the treatment liquid reacts with the ink to aggregate the color material (pigment) and has an effect of promoting separation of the color material (pigment) and the solvent. The treatment liquid application device 42 is provided with a storage portion 46 in which the treatment liquid is stored, and a part of the gravure roller 48 is immersed in the treatment liquid.

  A rubber roller 50 is disposed in pressure contact with the gravure roller 48, and the rubber roller 50 contacts the recording surface (front surface) side of the paper P to apply the processing liquid. Further, a squeegee (not shown) is in contact with the gravure roller 48 to control the amount of treatment liquid applied to the recording surface of the paper P. In the treatment liquid drying apparatus 44, a hot air nozzle 54 and a heater 56 are disposed in the vicinity of the surface of the treatment liquid application drum 30. The sheet P on which the processing liquid has been applied to the recording surface and dried by the processing liquid application unit 14 is conveyed to an intermediate conveyance unit 58 provided between the processing liquid application unit 14 and the image forming unit 16.

<Intermediate transport section>
An intermediate transport drum 58 is rotatably provided in the intermediate transport unit 58, and the leading end of the paper P is held on the surface of the intermediate transport drum 34 via a holding member 32 provided in the intermediate transport drum 34. The sheet P is transported downstream by the rotation of the intermediate transport drum 34.

<Image forming unit>
An image forming drum 36 is rotatably provided in the image forming unit 16, and the sheet P is held on the surface of the image forming drum 36 via a holding member 32 provided on the image forming drum 36 to form an image. The sheet P is conveyed downstream by the rotation of the drum 36.

  Above the image forming drum 36, a head unit 66 composed of a single-pass inkjet line head 64 is disposed in the vicinity of the outer peripheral surface of the image forming drum 36. In this head unit 66, for example, YMCK inkjet line heads 64, which are basic colors, are arranged along the circumferential direction of the image forming drum 36, and an image is formed on the paper P with droplets of each color.

  The inkjet line head 64 determines droplet landing positions with high accuracy by ejecting liquid droplets in synchronization with an encoder (not shown) that detects the rotational speed disposed on the image forming drum 36, and at the same time, the image forming drum. The droplet discharge unevenness can be reduced without depending on the shake of 36, the accuracy of the rotating shaft 68, and the drum surface speed.

  The head unit 66 can be retracted from the upper part of the image forming drum 36, and maintenance operations such as cleaning of the nozzle surface of the inkjet line head 64 and discharging of the thickened ink are performed on the head unit 66 at the upper part of the image forming drum 36. It may be configured to be implemented by evacuating.

  The sheet P on which the image is formed on the recording surface is transported to an intermediate transport unit 70 provided between the image forming unit 16 and the ink drying unit 18 by the rotation of the image forming drum 36. Since the configuration is substantially the same as that of the intermediate conveyance unit 58, description thereof is omitted.

<Ink drying section>
A drying drum 38 is rotatably provided in the ink drying unit 18, and a plurality of hot air nozzles 72 and IR heaters 74 are disposed on the top of the drying drum 38 in the vicinity of the surface of the ink drying unit 18. ing.

  Here, as an example, the pair of IR heaters 74 arranged in parallel with the hot air nozzles 72 are alternately arranged so that the hot air nozzles 72 are arranged on the upstream side and the downstream side. In addition to this, a large number of IR heaters 74 are arranged on the upstream side to irradiate a large amount of heat energy on the upstream side to increase the temperature of moisture, and a large number of hot air nozzles 72 are arranged on the downstream side to blow off saturated water vapor. Also good.

  Here, the hot air nozzle 72 is arranged so that the blowing angle of the hot air is inclined toward the rear end side of the paper. As a result, the flow of hot air from the hot air nozzle 72 can be collected in one direction, and the sheet can be pressed against the drying drum 38 and the sheet can be held on the surface of the drying drum 38.

  With the hot air generated by the hot air nozzle 72 and the IR heater 74, the solvent separated by the color material aggregating action is dried in the paper image forming unit, and a thin image layer is formed.

  Although the warm air varies depending on the paper conveyance speed, it is usually set to 50 ° C. to 70 ° C., and the ink surface temperature is set to 50 ° C. to 60 ° C. by setting the temperature of the IR heater 74 to 200 ° C. to 600 ° C. It is set to be. The evaporated solvent is discharged together with air to the outside of the image forming apparatus 10, but the air is recovered. This air may be cooled by a cooler / radiator or the like and recovered as a liquid.

  The sheet on which the image on the recording surface has been dried is conveyed to the intermediate conveyance unit 76 provided between the ink drying unit 18 and the image fixing unit 20 by the rotation of the drying drum 38. Since the configuration is substantially the same as that of the transport unit 58, description thereof is omitted.

<Image fixing unit>
An image fixing drum 40 is rotatably provided in the image fixing unit 20. In the image fixing unit 20, latex particles in a thin image layer formed on the paper P are heated / pressurized and melted. And has a function of fixing and fixing on the paper P.

  A heating roller 78 is disposed above the image fixing drum 40 in the vicinity of the surface of the image fixing drum 40. The heating roller 78 has a halogen lamp incorporated in a metal pipe made of aluminum or the like having a good thermal conductivity. The heating roller 78 applies heat energy equal to or higher than the Tg temperature of the latex. As a result, the latex particles are melted and pressed into the irregularities on the paper P for fixing, and the irregularities on the surface of the image are smoothed to obtain glossiness.

  A fixing roller 80 is provided on the downstream side of the heating roller 78. The fixing roller 80 is disposed in pressure contact with the surface of the image fixing drum 40 so as to obtain a nip force with the image fixing drum 40. I have to. Therefore, at least one of the fixing roller 80 and the image fixing drum 40 has an elastic layer on the surface and a uniform nip width with respect to the paper P.

  After the above steps, the paper P on which the image on the recording surface is fixed is conveyed to the discharge unit 21 provided on the downstream side of the image fixing unit 20 by the rotation of the image fixing drum 40.

  Although the image fixing unit 20 has been described in the present embodiment, the image fixing unit 20 may be configured to dry and fix the image formed on the recording surface by the drying drum 38, and the image fixing unit 20 is not necessarily essential.

<Structure of droplet discharge head>
An ink jet line head according to an embodiment of the present invention includes the droplet discharge head shown in FIGS.

  2 shows the principle of operation of the inkjet line head 64, and FIG. 3 shows a structural example of the inkjet line head 64. As shown in FIG.

  As shown in FIG. 2B, a plurality of supply channels 210 are arranged in the head plate 100 in the transport direction of the paper P, and ink S is supplied from an ink tank (not shown). The ink S is filtered by a filter (not shown) and supplied to the supply flow path 210 from the liquid circulation port 216. The supply channel 210 is provided with a plurality of ejection elements 104 that eject one-dot ink droplets, and the ink S supplied from the supply channel 210 is ejected as ink droplets.

  As shown in FIG. 2A, a plurality of ejection elements 104 provided on the head plate 100 are supplied with a pressure chamber 212 to which ink S is supplied from a supply channel 210, and ink S pressurized in the pressure chamber 212 is dropped. For each of the nozzles 214 for discharging, the diaphragm 200 for pressurizing the pressure chamber 212 to press the ink S, the piezoelectric body 202 for driving the diaphragm 200, the drive wiring 204 for applying an electric signal to each piezoelectric body, and the nozzle 214 Provided between the diaphragm 200 and the piezoelectric body 202 are an individual electrode 206 that is provided and applied with a voltage from the drive wiring, a connection terminal 208 (not shown) that electrically connects the drive wiring 204 to the outside of the head plate 100. A common electrode 220 (not shown) that is grounded (0 V), an insulating layer 222 (not shown) that is provided between the common electrode and the drive wiring 204 and electrically insulates the two are provided. It has been kicked. The connection terminal 208 and the common electrode 220 are connected to a piezoelectric drive circuit on an electric substrate (not shown), and can individually drive each ejection element 104.

  In addition, the driving waveform applied to the piezoelectric body 202 of the ejection element 104 when driving is, for example, a square wave having a pulse width that causes the ink in the pressure chamber to resonate. When the pulse width is 1 / (2 × f) (seconds) with respect to the resonance frequency f (Hz) of ink, ink can be efficiently ejected.

  Furthermore, the square wave voltage varies greatly depending on the design of the inkjet head to be used, the displacement characteristics of the piezoelectric body, and the viscosity of the ink. In the example of the present application, the ejection ink droplet speed is 9 (with an amplitude of about 14 (V). m / sec), which is appropriate. If a plurality of pulses are applied, a plurality of drops can be ejected.

  Further, as shown in FIG. 2C, a correction actuator 300 is provided on the drive wiring 204 corresponding to the ejection element 104. Even if the correction actuator 300 is provided in the drive wiring 204 for energizing all the discharge elements 104, or is provided mainly in the vicinity of the center in the longitudinal direction of the supply flow path 210, the correction actuator 300 is not provided in the vicinity of both ends or a number. It may be arranged such as reducing the number of times.

  For example, as shown in FIG. 2C, the correction actuator 300 is formed at a location where the drive wiring 204 extending from the connection terminal 208 to the ejection element 104 contacts the outside of the wall surface of the supply flow path 210. The correction actuator 300 is provided with a doughnut-shaped individual electrode 304 on a piezoelectric body 302 and forms a displacement portion 306.

  The individual electrode 304 is provided on the drive wiring 204. If the ejection element 104 connected to the drive wiring 204 provided with the correction actuator 300 is applied with a drive voltage by a control means (not shown), the correction actuator is simultaneously applied. A driving voltage is also applied to 300, and the correction actuator 300 is also driven simultaneously with the ejection element 104.

  Detailed structures of the ejection element 104 and the correction actuator 300 are shown in FIGS. FIG. 3 shows the structure of the ejection element according to the first embodiment of the present invention.

  As shown in FIGS. 3A and 3B, when a voltage is applied to the individual electrode 206 formed on the piezoelectric body 202 with the common electrode 220 interposed therebetween, the piezoelectric material as shown in FIG. The body 202 tends to contract in the vicinity of the center in contact with the individual electrode 206 as indicated by an arrow 203. At the same time, as a result of the peripheral portion of the piezoelectric body 202 not in contact with the individual electrode 206 trying to expand, the piezoelectric body 202 is displaced in the direction of pressurizing the pressure chamber 212 as indicated by an arrow 201.

  On the other hand, as shown in FIGS. 4A and 4B, the correction actuator 300 is configured to surround the displacement portion 306 with a doughnut-shaped individual electrode 304 provided on the piezoelectric body 302. When a voltage is applied to 304, as shown in FIG. 4C, the peripheral portion of the piezoelectric body 302 that is in contact with the individual electrode 304 tends to contract, and a portion near the center that is not in contact with the individual electrode 304 is indicated by an arrow 303. As a result of the expansion, the piezoelectric body 302 is displaced in the direction of depressurizing the supply flow path 210 as indicated by an arrow 301.

  The piezoelectric bodies 202 and 302 are bonded to the vibration plate 200 by forming electrode layers on both surfaces of one piezoelectric body having substantially the same size as the head plate 100, and the piezoelectric bodies 202 and 302 and the individual electrodes 206, 304 is formed by etching, leaving only necessary portions. Thereafter, the insulating layer 222 is formed, and the drive wiring 204 and the connection terminal 208 that connect the individual electrode 206 and the correction actuator 300 are formed by plating or sputtering. Although the piezoelectric body 202 may remain in the insulating layer 222 portion, it is desirable to provide the insulating layer 222 because there is a risk of causing dielectric breakdown if the piezoelectric body 202 is too thin.

<Effects of First Embodiment>
The operation of the inkjet line head according to the first embodiment of the present invention will be described below.

  When an electric signal is applied to the drive wiring 204 of each ejection element 104 as shown in FIG. 2A, the piezoelectric body 202 is displaced, and the ink S drops from the pressurized pressure chamber 212 through the nozzle 214. Are discharged.

The ejection pressure not only ejects the ink S from the nozzle 214 but also generates a flow and pressure for pushing the ink S to the throttle unit 213 for supplying the ink S.
The flow and pressure toward the narrowed portion 213 are transmitted to each of the pressure chambers 212 communicated with each other through the supply flow path 210 of the ink S, affect the ejection force of the ink S in the other pressure chambers 212, and are ejected. Variations in the speed and volume of ink droplets occur (fluid crosstalk).

 In the present embodiment, when the discharge element 104 that is a discharge actuator or the shape of the individual electrode 206 or the individual electrode 304 of the correction actuator 300 is devised, when these are connected to the same drive wiring 204 and driven. In addition, both are displaced in opposite directions.

  Thus, while the same drive signal is applied on the same drive wiring 204, the ejection element 104 and the correction actuator 300 are displaced in the opposite directions, and fluid crosstalk can be reduced.

  That is, by adopting such an electrode shape, the ejection piezoelectric body 202 and the correction piezoelectric body 302 are displaced in the opposite directions while applying the same drive voltage, and the respective displacement volume amounts can be set appropriately. For example, the positive pressure generated in the discharge element 104 with respect to the supply flow path 210 can be canceled by the negative pressure generated in the correction actuator 300, and fluid crosstalk can be effectively reduced.

  In addition, since the correction actuator 300 is provided in the middle of the drive wiring 204 of the ejection element 104, no dedicated wiring is required. In addition, if the ejection element 104 is driven, the correction actuator on the same drive wiring 204 is simultaneously used. Since 300 is also driven, it can be configured such that a dedicated control means is not required.

  The displacement volume of the discharge element 104 is determined so as to obtain the required discharge performance. When ejection is performed under these conditions, the amount of ink S pushed out from the throttle 213 to the supply flow path 210 can be easily obtained by simulation, but the displacement volume of the correction actuator 300 is the ink S pushed out to the supply flow path 210. Should be approximately equal to the amount of.

In the present embodiment, the ejection element 104 and the correction actuator 300 use independent piezoelectric bodies, but the invention is not limited to this, and a continuous piezoelectric body may be used, and each piezoelectric body of one head plate 100 may also be used. May be all in one (integral). In the present embodiment, the donut-shaped individual electrode 304 is used for the correction actuator 300. Conversely, the individual electrode 206 of the ejection element 104 has a donut shape, and the correction individual electrode 304 has a hole in the center. It may be a so-called solid electrode without any.
Second Embodiment
In the first embodiment, the shape of the individual electrode 206 of the ejection element 104 and the individual electrode 304 of the correction actuator 300 is such that one is a solid electrode and the other is a donut-shaped electrode. One generates a positive pressure with respect to the supply flow path 210 and the other generates a negative pressure.

  In this embodiment, the individual electrode 206 and the individual electrode 306 are both solid electrodes, or both are donut-shaped electrodes, and both piezoelectric bodies are polarized in opposite directions.

  That is, the ejection element 104 and the piezoelectric body of the correction actuator 300 are polarized in opposite directions, so that when the same drive signal is applied, they are displaced in opposite directions, while on the other hand, with respect to the supply channel 210 The positive pressure and the other can generate negative pressure.

 At this time, since one piezoelectric body polarized in the opposite direction has a smaller displacement than the other, it is desirable to use the piezoelectric body 302 of the correction actuator 300. Or you may be set as the structure which enlarges an actuator area rather than 1st Embodiment.

  Further, instead of polarization in the opposite direction, a piezoelectric body polarized in the same direction may be attached upside down so that the piezoelectric body 202 and the piezoelectric body 302 are opposite to each other. In this configuration, the same displacement can be obtained for both piezoelectric bodies.

  Further, if the individual electrodes are all solid electrodes, the area of the electrodes can be reduced, so that the electrode accuracy can be easily obtained and the mounting density can be increased.

<Third Embodiment>
The correction actuators 300 may be provided in one-to-one correspondence with the pressure chambers 212 as in the first embodiment, but one correction actuator 300 is provided for the two pressure chambers 212, or The number of correction actuators 300 may be reduced such that one correction actuator 300 is provided for the three pressure chambers 212. In this case, it is desirable to provide the correction actuator 300 in any one of the ejection elements 104 that form adjacent dots when ejecting droplets.

  That is, in medium density to high density drawing where density unevenness due to crosstalk is conspicuous, in order to reduce the feeling of roughness, the ink S is ejected without hitting adjacent dots. Further, the correction actuator 300 can be driven.

  In addition, since the fluid crosstalk is a propagation of vibrations, the pressure chamber 212 is more susceptible to influence as the pressure chamber 212 provided at a shorter distance. It may be provided corresponding to 212 only. For example, even if the correction actuator 300 is provided only in the pressure chamber 212 of 1/4 to 3/4 closer to the center, an effect can be obtained in reducing crosstalk.

  With this configuration, crosstalk can be reduced without providing the correction actuator 300 for all the ejection elements 104, and a simple configuration can be achieved at low cost.

<Fourth embodiment>
In the configuration in which the correction actuator 300 is installed only on a part of the ejection elements 104 as in the third embodiment, the piezoelectric body 302 of the correction actuator 300 is used as a sensor for measuring the internal pressure of the supply flow path 210. Also good. In order to use the piezoelectric body 302 as a sensor for measuring the internal pressure, the wiring connected to the piezoelectric body 302 is connected to a drive circuit, and is connected to a voltage detection circuit (not shown). In other words, the voltage detected by switching from the piezoelectric drive circuit to the pressure detection circuit by the switch on the electric substrate (not shown), in which the connection terminal 208 and the common electrode 220 are connected, is converted into an internal pressure value and detected. . This change in pressure value is processed by a control circuit (not shown), and the piezoelectric body 202 of the ejection element 104 to which the correction actuator 300 is not connected is driven as a result.

  That is, the pressure due to the natural vibration excited inside the supply flow path 210 due to the generated crosstalk is detected, and the piezoelectric body 202 of the ejection element 104 to which the correction actuator 300 is not connected is driven so as to attenuate this pressure. By doing so, it is possible to reduce the natural vibration generated inside the supply flow path. In this case, if the piezoelectric body 202 is driven at such a displacement as not to eject a droplet from the nozzle 214, it is possible to prevent the occurrence of an image failure due to unexpected ejection.

<Others>
As mentioned above, although the Example of this invention was described, it cannot be overemphasized that this invention is not limited to said Example at all, and can implement in a various aspect in the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the configuration in which the sheet P is held and transported on the surface of the drum is described as an example. However, the present invention is not limited to this. For example, the configuration using an endless belt-shaped transport belt, It is also possible to apply the present invention to a configuration for carrying.

  In the above-described embodiment, the processing liquid is applied to the paper P by the processing liquid application unit 14 and dried, and then droplets are ejected to the paper P by the head unit 66. Of course, the present invention is not limited to this. For example, the present invention can be applied to a normal inkjet printer that holds normal paper (plain paper) and conveys it as it is, and directly ejects liquid droplets on the surface to form an image. .

  Furthermore, the discharged liquid is not limited to ink, and may be applied to, for example, substrate pattern formation during etching.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Paper feed conveyance part 14 Processing liquid application part 16 Image formation part 18 Ink drying part 20 Image fixing part 64 Inkjet line head 66 Head unit 100 Head plate 104 Discharge element 200 Diaphragm 202 Piezoelectric body 204 Drive wiring 206 Individual Electrode 208 Connection terminal 210 Supply flow path 212 Pressure chamber 214 Nozzle 300 Correction actuator P Paper S Ink

Claims (9)

A liquid supply channel through which liquid is supplied;
A plurality of pressure chambers communicating with the liquid supply channel and pressurizing the liquid;
A nozzle communicating with the pressure chamber and discharging droplets;
A first pressure generating means provided for each pressure chamber and pressurizing the pressure chamber;
Each of the first pressure generating means is provided on the back surface of the surface on the supply path through which the liquid of the member constituting one wall of the liquid supply flow path flows, and an electric signal is respectively sent to the first pressure generating means. Drive wiring to transmit,
The second surface is provided on the drive wiring outside the wall surface of the liquid supply flow path, and displaces the one surface of the liquid supply flow path in a reverse phase when the same drive voltage as the first pressure generating means is applied . Pressure generating means ,
One of the first pressure generation means and the second pressure generation means is connected to the drive wiring and a solid electrode, and the other is a droplet discharge head connected by a donut-shaped electrode surrounded by a closed curve . The droplet discharge head according to claim 1, wherein the first pressure generating unit and the second pressure generating unit are piezoelectric bodies. 3. The droplet according to claim 1, wherein a part of the drive wiring contacts the piezoelectric body on the one surface of the liquid supply flow path to form the second pressure generating unit. Discharge head. The first pressure generating means and the second pressure generating means are both solid electrodes or connected to the drive wiring by a donut-shaped electrode surrounded by a closed curve with a displacement range, and the first pressure generating means 4. The liquid droplet ejection head according to claim 2, wherein the second pressure generating means have opposite polarization directions. A ratio of the second pressure generating means provided in the drive wiring is higher at a location near the longitudinal center of the liquid supply channel than at a location near the longitudinal end of the liquid supply channel. The droplet discharge head according to any one of claims 1 to 4. By operating the second pressure generating means as a vibration detector, a natural vibration in the liquid in the liquid supply flow path is detected and connected to the drive wiring in which the second pressure generating means is not provided. 6. The liquid droplet ejection head according to claim 1, wherein the first pressure generation unit is displaced in a direction to cancel the natural vibration. 5. The droplet discharge head according to claim 1, wherein the second pressure generation unit is provided for each of the drive wirings. The droplet according to any one of claims 2 to 7, wherein the first pressure generating means and the second pressure generating means are formed by separating a single piezoelectric body. Discharge head. An image forming apparatus comprising the droplet discharge head according to claim 1.

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