JP2008037055A - Liquid droplet ejection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet ejection apparatus capable of surely removing stains such as an ejection liquid containing paper powder or sticky substances in cleaning a liquid droplet ejection head. <P>SOLUTION: The liquid droplet ejection apparatus comprises a liquid droplet ejection head for discharging an ejection liquid in droplets, an ejection liquid supply means for supplying the ejection liquid to the liquid droplet ejection head, a reservoir tank provided between the ejection liquid supply means and the liquid droplet ejection head for temporarily storing the ejection liquid to be supplied to the liquid droplet ejection head, an air amount adjusting means for adjusting air in the reservoir tank to a predetermined amount, a pressurizing means for jetting the ejection liquid onto the nozzle surface of the liquid droplet ejection head by pressurizing the air in the reservoir tank after the air amount is adjusted at the air amount adjusting means, and a wiping means for wiping off the ejection liquid jetted on the nozzle surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a droplet discharge device, and more particularly, to a droplet discharge device that can reliably wet-wipe discharge liquid overflowing on a nozzle surface of a droplet discharge head.

  In an ink jet printer, if printing is performed for a long time, the nozzle surface is contaminated by the ejected ink, causing a defective ejection direction in which the ink is ejected in an unscheduled direction, or bubbles are entrained in the nozzles opened on the nozzle surface. Or the thickened ink may clog the nozzles, resulting in ejection failure.

  Therefore, printing is stopped and the nozzle surface is cleaned every predetermined time or every predetermined number of printed sheets.

As such an ink jet printer,
(1) A pressure pump, an air tank connected to the pressure pump and supplied with air generated by the pressure pump, and an air tank connected to the air tank and supplied with air from the air tank. And a plurality of ink jet heads for discharging ink liquids supplied from the plurality of ink tanks, and the number of the pressure pumps and the air tanks is determined by the number of the ink tanks. In the image forming apparatus reduced in number, before performing sucking, a discharge control unit that discharges ink with a different ink amount for each of the plurality of inkjet heads, and after the discharge control of the ink by the discharge control unit, the plurality of inkjets A cleaning member that slides the cleaning member with respect to the head and performs a sucking operation (Patent Document 1), and
(2) An ink tank that stores ink to be supplied to each head unit, a circulation forward path that is connected to the ink tank and through which ink supplied to each head unit circulates, and ink discharged from each head unit. A circulation return path serving as a circulation path, a plurality of supply paths communicating between the circulation forward path and the ink supply holes of the ACK head unit, and the ink stored in the ink tank is fed to the circulation forward path; An ink jet printer comprising an ink circulation mechanism for collecting ink from the circulation return path to the ink tank via the head units and circulating the ink (Patent Document 2)
Has been proposed.

  In the image forming apparatus described in Patent Document 1, when a cleaning member is slid with respect to an ink jet head for sucking, the sealed ink jet head is pressurized with an air tank and a pressure pump, and the nozzle of the ink jet head is used. The ink is discharged from the surface.

In Patent Document 2, the ink circulation mechanism stores the collected ink, and a sub-tank communicated with the ink tank, and a first valve that opens and closes an ink flow path between the ink tank and the sub-tank. An ink jet printer is described that includes a second valve that opens and closes an ink flow path between a sub tank and a circulation return path, and a pressurizing unit that pressurizes ink stored in the ink tank and pumps the ink in a circulation forward path. (Patent Document 2 and Claim 2). And what has an air release part is described as said sub tank.
JP-A-2005-193661 JP-A-11-342634

When wiping the nozzle surface, the ink is not discharged from the nozzle surface of the ink jet head, and it is necessary to simply overflow the ink. However, the pressurizing force necessary to overflow the ink from the nozzle surface is 100 mH. _As small as ₂ O (1/100 atm). Therefore, if the amount of ink overflow is controlled with high accuracy, the applied pressure must be controlled in units of several mmH ₂ O, that is, 10 ⁻⁴ atm.

However, in the image forming apparatus of Patent Document 1, since the pressure at the time of discharging the ink from the nozzle surface is directly controlled by the pressurizing pump, it is extremely difficult to control the applied pressure in units of several mmH ₂ O. It is thought that.

Also in the ink jet printer described in Patent Document 2, since the water level in the atmosphere opening portion of the sub tank varies in the range of several millimeters to several centimeters, it is difficult to control the applied pressure in units of several millimeters H ₂ O. .

  The present invention has been made in order to solve the above-described problems. The liquid discharge head such as an ink jet head has a positive pressure to allow an appropriate amount of discharge liquid to overflow from the nozzle. It is an object of the present invention to provide a droplet discharge device that can realize with high accuracy control of the amount of discharge liquid overflowing from a positive pressure or a droplet discharge head with high accuracy.

  According to a first aspect of the present invention, there is provided a droplet discharge head that discharges a discharge liquid in droplets, a discharge liquid supply unit that supplies the droplet discharge head with the discharge liquid, the discharge liquid supply unit, and the droplet discharge head A reservoir tank for temporarily storing the discharge liquid supplied to the droplet discharge head, an air amount adjusting means for adjusting the air in the reservoir tank to a predetermined amount, and the air amount adjusting means After adjusting the amount of air in the reservoir tank, pressurizing means for pressurizing the air in the reservoir tank to overflow the discharge liquid on the nozzle surface of the liquid droplet discharge head, and the discharge overflowing the nozzle surface The present invention relates to a droplet discharge device comprising a wiping means for wiping a liquid.

  In the droplet discharge device, air is introduced into or led out from the reservoir tank by the air amount adjusting means to adjust the air amount in the reservoir tank, and then the reservoir tank is pressurized by the pressurizing means. Pressurize inside the tank.

  According to a second aspect of the present invention, the air amount adjusting means is configured to open and close the open air communication channel that allows the reservoir tank to communicate with the atmosphere, and to discharge the discharge liquid so that a predetermined amount of discharge liquid exists in the reservoir tank. A discharge liquid amount control means for introducing or deriving, adjusting the liquid amount of the discharge liquid in the reservoir tank to a predetermined liquid amount by the discharge liquid amount control means in a state where the atmosphere communication channel is opened, 2. The droplet discharge device according to claim 1, wherein the atmospheric communication flow path is closed.

  In the droplet discharge device, the discharge liquid in the reservoir tank is controlled to a predetermined amount by introducing or discharging the discharge liquid by the discharge liquid amount control means in a state where the atmosphere communication channel is opened, thereby Controls the amount of air in the reservoir tank. After the amount of air in the reservoir tank is controlled to a predetermined amount by introducing or discharging the discharge liquid into the reservoir tank, the air amount in the reservoir tank is set to a predetermined amount by closing the atmosphere communication channel. Retained.

  According to a third aspect of the present invention, the pressurizing unit adjusts the air amount in the reservoir tank by the air amount adjusting unit, and then injects a predetermined amount of air into the reservoir tank. The liquid droplet ejection apparatus according to claim 1, which pressurizes the liquid.

  According to a fourth aspect of the present invention, the pressurizing unit adjusts the air amount in the reservoir tank by the air amount adjusting unit, and then injects the discharge liquid into the reservoir tank by the discharge liquid supplying unit. The droplet discharge device according to claim 1, wherein the inside of the reservoir tank is pressurized.

  As described above, according to the present invention, a liquid discharge head such as an ink jet head is set to a positive pressure so that an appropriate amount of discharge liquid overflows from the nozzle. Provided is a droplet discharge device capable of realizing, with a simple configuration, the amount of discharge liquid overflowing from a head with high accuracy.

1. Embodiment 1
An example of an ink jet recording apparatus included in the liquid droplet ejection apparatus according to the present invention will be described below.

  As shown in FIGS. 1 and 2, the inkjet recording apparatus 12 according to the first embodiment is provided with a housing 14, a paper feed tray 16 that is provided at the bottom of the housing 14, and supplies paper P, and a paper feed tray. 16 includes an image recording unit 30 that records an image on the paper P supplied from 16, and a paper discharge tray 46 from which the paper P on which the image is recorded by the image recording unit 30 is discharged.

  Between the image recording unit 30 and the paper feed tray 16, a group of paper feed roller pairs 20 that convey the paper P along a predetermined paper feed path 22 are provided. A group of paper discharge roller pairs 42 for conveying the paper P along a predetermined paper discharge path 44 is provided between the two. In addition, a pickup roller 18 that takes out the paper P one by one is provided between the pair of paper feed rollers 20 on the most upstream side and the paper feed tray 16.

  Between the image recording unit 30 and the paper discharge and Example 16, an image is recorded on the upper surface of the image recording unit 30 and the paper P sent to the paper discharge path 44 is moved along the conveyance path 52. A group of roller pairs 50 returning to the entrance of the image recording unit 30 is provided.

  As shown in FIGS. 1 to 3, the image recording unit 30 includes a recording head including four recording heads 32 corresponding to yellow (Y), magenta (M), cyan (C), and black (K) colors. The conveyance belt 28 that conveys the recording paper P so as to pass through the array 31 and the ejection region SE where ink is ejected from the four recording heads 32, and the driving roller 24 and the driven roller 26 on which the conveyance belt 28 is stretched And a peeling claw 40 for peeling the paper P on which an image has been recorded by the recording head array 31 from the conveying belt 28. On the nozzle surface 32N of the recording head 32, a large number of nozzles 33 that eject ink are opened. As shown in FIG. 12, if an ink overflow nozzle 70 that discharges the same ink that is discharged from the nozzle 33 during wiping is opened upstream of the nozzle 33 with respect to the wiping direction, the nozzle surface Since the portion where the nozzle 33 is opened in 32N is wiped in a state where it is reliably wet with ink, damage to the nozzle surface 32N due to so-called dry wiping can be prevented, which is preferable.

  On both sides of the recording head array 31, four maintenance units 34 that perform maintenance operations on the recording heads 32 are disposed so as to correspond to the recording heads 32. At the time of maintenance, as shown in FIG. 2, the recording head array 31 moves upward, and the maintenance unit 34 moves into a gap formed between the conveyance belt 28 and enters. Then, a predetermined maintenance operation (suction, dummy jet, wiping, capping, etc.) is performed while facing the nozzle surface 32N.

  A total of four ink tanks 54 for supplying ink to the recording heads 32 are provided above the recording head array 31, one for each recording head 32.

  A charging roller 36 to which a power source 38 is connected is disposed on the upstream side of the recording head array 31. The charging roller 36 is driven while sandwiching the conveyance belt 28 and the paper P between the driven roller 26 and either a pressing position for pressing the paper P against the conveyance belt 28 or a separation position separated from the conveyance belt 28. Take. Since a predetermined potential difference is generated between the charging roller 36 and the driven roller 26 at the pressing position, the sheet P can be electrified and electrostatically adsorbed onto the transport belt 28.

  As shown in FIG. 4, the maintenance unit 34 includes a cap 37 for capping the nozzle surface 32N of the recording head 32 and a blade 35 for wiping the nozzle surface 32N.

  Further, as shown in FIG. 4, an ink supply pump 56 and a reservoir tank 58 are interposed between the ink tank 54 and the recording head 32. The ink tank 54 and the ink supply pump 56 correspond to the discharge liquid supply means in the present invention. The height of the reservoir tank 58 is set so that the outlet is lower than the nozzle surface 32N by the height H.

A liquid level sensor 57 for measuring the height of the ink level is provided in the reservoir tank 58. The reservoir tank 58 is further provided with an air communication channel 59 that can be opened and closed by an air release valve 59A provided in the middle.
The ink supply pump 56 is centered on a disk 56B and a disk 56B in which a plurality of, for example, four, handling rollers 56A for handling the ink supply tube 55 connecting the ink tank 54 and the reservoir tank 58 are arranged at the peripheral part. This is a tubing pump comprising a motor (not shown) that rotates around a point. When the disk 56B rotates in the direction of arrow a, 0 part is being supplied from the ink supply tank 54 toward the reservoir tank 58. 55 is handled and ink is sent out. In the ink supply pump 56, the ink delivery flow rate can be set with high accuracy by setting the rotation speed of the disk 56B. Further, the ink does not flow back toward the ink supply tank 54 unless the disk 56B is reversed. The ink supply pump 56 and the air release valve 59A correspond to the air amount adjusting means in the present invention. The ink supply pump 56 also corresponds to a pressurizing unit.

Hereinafter, the operation of the inkjet recording apparatus 12 will be described.
As described above, at the time of image formation, the maintenance unit 34 moves to both sides of the recording head array 31, and the recording head array 31 comes close to the conveyance belt 28. At this time, the atmosphere release valve 59A of the atmosphere communication channel 59 is in an open state. Since the outlet of the reservoir tank 58 is lower than the nozzle surface 32N by the height H as described above, the inside of the nozzle 33 of the recording head 32 is held at a negative pressure as shown in FIG. Yes.

  The paper P is picked up one by one from the paper feed tray 16 by the pickup roller 18 and sent to the paper feed roller pair 20. Then, it is inserted into the image recording unit 30 through the paper feed path 22.

  The paper P is transported in the ejection area SE by the transport belt 28 in the image recording unit 30, and simultaneously, Y, M, C, and K inks are ejected from each recording head 32, and a full color image is formed on the upper surface of the paper P. To be recorded.

  The paper P on which the full-color image is recorded is peeled off from the transport belt 28 by the peeling claw 40 and introduced into the paper discharge path 44 by the paper discharge unit 43. The paper P introduced into the paper discharge path 44 is conveyed toward the paper discharge tray 46 by the paper discharge roller pair 42.

  When an image is recorded by ejecting ink from the recording head 32 for a long time, the ink adheres in a ring shape around the nozzles 33 on the nozzle surface 32N of the recording head 32 as shown in FIG.

  Therefore, after recording an image for a certain period of time or after recording an image on a predetermined number of sheets of paper P, a control computer (not shown) that controls the entire inkjet recording apparatus 12 issues a wiping command in step S2 of FIG. Output.

  When the wiping command is input, it is determined in step S4 in FIG. 8 whether or not the remaining amount of ink in the ink tank 54, that is, the remaining amount of the main tank is greater than or equal to a predetermined value.

  When it is determined that the main tank remaining amount is equal to or greater than the predetermined value, the maintenance unit 34 moves to the maintenance position in step S6, and maintenance of the nozzle 33 is started in the following procedure. On the other hand, if it is determined that the remaining amount of the main tank is less than the predetermined value, an ink tank replacement message is output in step S22.

  First, in step S <b> 8, the ink supply pump 56 is restarted, and ink is supplied to the reservoir tank 58. At the same time, in step S10, based on the liquid level detection signal from the liquid level sensor 57, it is determined whether or not the ink level in the reservoir tank 58 has reached a predetermined level. When it is determined in step S10 that the ink level has reached a predetermined level, the air release valve 59A is closed in step S12. Then, after 1 second has elapsed, the ink supply pump 56 stops in step S16. As a result, a predetermined amount of ink is inserted into the reservoir tank 58 with the atmosphere release valve 59A being closed, the inside of the reservoir tank 58 is pressurized, and a positive back pressure is applied to the ink in the nozzle 33. . Note that a driving wave may be applied simultaneously with the application of the back pressure to the recording head 33. As a result, the ink overflows in a spherical shape from the nozzle 33 as shown in FIG.

  When the ink supply pump 56 stops, the blade 35 operates in step S18 of FIG. 8, and the blade 35 moves in the direction of the arrow as shown in FIG. 9C to wipe the nozzle surface 32N. When wiping is completed, the air release valve 59A is opened in step S20 of FIG. 8, the pressurization in the reservoir tank 58 is released, and at the same time, the blade 35 returns to the initial position. Then, the nozzle surface 32N is wiped again as shown in FIG. Thereby, the ink remaining on the nozzle surface 32N by the first wiping is completely removed.

  FIG. 11 shows the change in the ink level at the opening of the nozzle 33 on the nozzle surface 32N.

  When printing is performed by ejecting ink from the recording head 32, the reservoir tank 58 is fixed at a position lower than the nozzle surface 32N, and negative back pressure is applied to the ink. Therefore, unless the necessary pulse wave is applied to the recording head 32, the ink surface forms a concave surface that is recessed toward the inside of the nozzle 33, as shown in FIG.

  When the wiping mode is started and a positive back pressure is applied to the ink in the nozzle 33, the ink protrudes in a convex shape from the opening of the nozzle 33 as shown in FIG. In this state, when a back pressure is further applied to the recording head 32, the ink overflows from the nozzle 33 in the form of a sphere or a drop as shown in FIGS.

  When the ink overflows from the nozzle surface 32N, the nozzle surface 32N is wiped by the blade 35 as shown in FIG. FIG. 11F shows the state of the ink liquid level when wiping is completed. When the wiping is completed, the reservoir tank 58 is still in the raised state, so that the ink protrudes spherically from the opening of the nozzle 33.

  When the wiping is completed, the atmosphere release valve 59A is opened, so that the nozzle 33 returns to the initial state as shown in FIG.

  The ink jet recording apparatus 12 according to the first embodiment sets the air in the reservoir tank 58 to a predetermined amount by controlling the liquid level height of the ink in the reservoir tank 58 to a predetermined level during wiping. When the air amount in the reservoir tank 58 is set to a predetermined amount, the air release valve 59A is closed to supply a predetermined amount of ink to the reservoir tank 58. As a result, the liquid level in the reservoir tank 58 rises and the air is compressed. The pressure of the air in the reservoir tank 58 can be set by the amount of ink supplied to the reservoir tank 58. Here, since the reservoir tank 58 and the recording head 32 communicate with each other through a pipe line, when the air in the reservoir tank 58 is compressed, the pressure corresponding to the compressed air passes through the ink in the pipe line. The back pressure is applied to the recording head 32.

In order to allow ink to overflow from the nozzle 33 without applying a driving wave to the recording head 32, it is necessary to apply a back pressure of about 50 to 100 mmH ₂ O, and thus it is necessary to control the back pressure in units of several mmH ₂ O. There is. Although it is considered difficult to control such a minute pressure with high accuracy in an ink jet recording apparatus that controls the back pressure of ink with a normal pump, in the ink jet recording apparatus 12 of the first embodiment, a reservoir tank Since the back pressure applied to the recording head 32 is controlled by the amount of ink supplied to 58, it is very easy to control the back pressure in units of several mmH ₂ O.

  In addition, while the back pressure is applied to the recording head 32, the inside of the nozzle 33 is naturally maintained at a positive pressure, so that the ink overflowing the nozzle surface 32N or the paper adhering to the nozzle surface 32N. The powder is not sucked into the nozzle 33. Therefore, since the nozzle surface 32N is wiped in a wet state, the nozzle surface 32N is not damaged by so-called dry wiping, and the nozzle 33 is not clogged by paper dust.

  Further, in the ink jet recording apparatus 12, the reservoir tank 58 is used for holding the inside of the nozzle 33 at a negative pressure so that ink is not discharged unless an image signal is input during normal printing. In this case, it is not necessary to add special hardware to overflow the ink on the nozzle surface 32N.

2. Embodiment 2
The overall configuration of the inkjet recording apparatus 112 according to the second embodiment is also as shown in FIGS. However, as shown in FIG. 5, the difference is that a pressure cylinder 60 is provided in the reservoir tank 58 instead of the air release valve 59.

  As shown in FIG. 6, the pressurizing cylinder 60 includes a bottomed cylindrical outer cylinder 61 attached to the ceiling surface of the reservoir tank 58, and a piston 62 that slides inside the outer cylinder 61. In the vicinity of the upper end portion of the outer cylinder 61, an atmosphere communication pipe 63 communicating with the atmosphere is provided. Since the piston 62 is positioned above the standby communication pipe 63 as shown in FIG. 6A during standby, the reservoir tank 58 communicates with the atmosphere via the outer cylinder 61 and the atmospheric communication pipe 63. At the time of air compression, as shown in FIG. 6B, the piston 62 descends below the atmosphere communication hole 63, so that the communication between the reservoir tank 58 and the atmosphere is cut off, and the air in the pressurizing cylinder 60 is It is pushed into the reservoir tank 58. Thereby, the air in the reservoir tank 58 is compressed.

  The piston 62 is moved up and down by, for example, an air cylinder, a hydraulic cylinder, a solenoid, or the like. Further, it may be moved up and down by a combination of a motor and a motion conversion mechanism such as a ball screw mechanism, a rack and pinion mechanism, or a foam gear mechanism that converts the rotation of the motor into a reciprocating motion.

Hereinafter, the operation of the inkjet recording apparatus 112 will be described.
As described above, at the time of image formation, the maintenance unit 34 moves to both sides of the recording head array 31, and the recording head array 31 comes close to the conveyance belt 28. At this time, since the cylinder 62 of the pressurizing cylinder 60 is at the highest position as shown in FIG. 6A, the reservoir tank 58 is in communication with the atmosphere. Since the outlet of the reservoir tank 58 is lower than the nozzle surface 32N by a height H as in the ink jet recording apparatus of the first embodiment, the interior of the nozzle 33 of the recording head 32 is as shown in FIG. It is held at negative pressure.

  The paper P is picked up one by one from the paper feed tray 16 by the pickup roller 18 and sent to the paper feed roller pair 20. Then, it is inserted into the image recording unit 30 through the paper feed path 22.

  The paper P is transported in the ejection area SE by the transport belt 28 in the image recording unit 30, and simultaneously, Y, M, C, and K inks are ejected from each recording head 32, and a full color image is formed on the upper surface of the paper P. To be recorded.

  The paper P on which the full-color image is recorded is peeled off from the transport belt 28 by the peeling claw 40 and introduced into the paper discharge path 44 by the paper discharge unit 43. The paper P introduced into the paper discharge path 44 is conveyed toward the paper discharge tray 46 by the paper discharge roller pair 42.

  When an image is recorded by ejecting ink from the recording head 32 for a long time, the ink adheres in a ring shape around the nozzles 33 on the nozzle surface 32N of the recording head 32 as shown in FIG.

  Therefore, after recording an image for a certain period of time or after recording an image on a predetermined number of sheets of paper P, a control computer (not shown) that controls the entire inkjet recording apparatus 12 issues a wiping command in step S102 of FIG. Output.

  When the wiping command is input, it is determined in step S104 in FIG. 13 whether or not the remaining amount of ink in the ink tank 54, that is, the remaining amount of the main tank is greater than or equal to a predetermined value.

  When it is determined that the main tank remaining amount is equal to or greater than the predetermined value, the maintenance unit 34 moves to the maintenance position in step S106, and maintenance of the nozzle 33 is started in the following procedure. On the other hand, if it is determined that the remaining amount of the main tank is less than the predetermined value, an ink tank replacement message is output in step S122.

The maintenance steps of the nozzle 33 are as follows.
First, in step S108, the ink supply pump 56 is restarted, and ink is supplied to the reservoir tank 58. At the same time, in step S110, based on the liquid level detection signal from the liquid level sensor 57, it is determined whether or not the liquid level of the ink in the reservoir tank 58 has reached a predetermined level. If it is determined in step S110 that the ink level has reached a predetermined level, the ink supply pump 56 is stopped in step S112. When the ink supply pump 56 stops, the pressure cylinder 60 is turned on in step 114, and the piston 62 is pushed down to the lowest end. As a result, the reservoir tank 58 is cut off from the atmosphere, and the air corresponding to the volume Vair of the pressure cylinder 60 is pushed in to pressurize the inside. Here, since the reservoir tank 58 and the recording head 32 communicate with each other through a pipe line, the pressure is transmitted to the recording head 32 and a positive back pressure is applied to the ink in the nozzle 33. Then, as shown in FIG. 9B, the ink overflows in a spherical shape from the nozzle 33. At this time, a drive waveform may be applied to the recording head 32 as necessary.

  Next, the blade 35 operates in step S116 of FIG. 13, and the blade 35 moves in the direction of the arrow as shown in FIG. 9C to wipe the nozzle surface 32N. When wiping is completed, the pressure cylinder 60 is turned off in the next step S118, in other words, the piston 62 is raised to the standby position. Thereby, since the reservoir tank 58 communicates with the standby, the internal pressurization is released. At the same time, the blade 35 returns to the initial position. Then, the nozzle surface 32N is wiped again as shown in FIG. Thereby, the ink remaining on the nozzle surface 32N by the first wiping is completely removed.

  The ink jet recording apparatus 112 according to the second embodiment has the same features as the ink jet recording apparatus according to the first embodiment.

FIG. 1 is a schematic diagram illustrating an overall configuration of the ink jet recording apparatus according to the first and second embodiments. FIG. 2 is a schematic explanatory view showing the ink jet recording apparatus shown in FIG. 1 in the cleaning mode. FIG. 3 is an enlarged view showing the configuration of the image recording unit in the ink jet recording apparatus shown in FIG. FIG. 4 is a schematic diagram illustrating a relative positional relationship among the ink tank, the recording head, and the reservoir tank in the ink jet recording apparatus according to the first embodiment. FIG. 5 is a schematic diagram illustrating a relative positional relationship among the ink tank, the recording head, and the reservoir tank in the ink jet recording apparatus according to the second embodiment. FIG. 6 is an enlarged view showing a detailed configuration of a pressure cylinder provided in a reservoir tank in the ink jet recording apparatus according to the second embodiment. FIG. 7 is a schematic plan view showing the state of ink adhesion on the nozzle surface at the end of printing. FIG. 8 is a flowchart showing a wiping procedure in the ink jet recording apparatus according to the first embodiment. FIG. 9 is a schematic diagram illustrating an ink overflow state and blade movement during wiping of the ink jet recording apparatus according to the first and second embodiments. FIG. 10 is a schematic diagram illustrating the movement of the blade when the nozzle surface is side-wiped in the ink jet recording apparatus according to the first embodiment. FIG. 11 is a schematic diagram illustrating an ink overflow state during wiping. FIG. 12 is a schematic diagram showing an example in which an ink overflow nozzle is provided adjacent to a printing nozzle in the recording head. FIG. 13 is a flowchart illustrating a wiping procedure in the inkjet recording apparatus according to the second embodiment.

Explanation of symbols

12 Inkjet recording apparatus 30 Image recording section 31 Recording head array 32N Nozzle surface 32 Recording head 33 Nozzle 34 Maintenance unit 35 Blade 36 Charging roller 37 Cap 54 Ink tank 56 Ink pump 56 Ink supply pump 57 Liquid level sensor 58 Reservoir tank 59 Atmospheric communication Flow path 59A Atmospheric release valve 60 Pressurizing cylinder 61 Outer cylinder 62 Piston 63 Atmospheric communication pipe 70 Ink overflow nozzle 112 Inkjet recording apparatus

Claims (4)

A droplet discharge head for discharging the discharge liquid in droplets;
A discharge liquid supply means for supplying a discharge liquid to the droplet discharge head;
A reservoir tank that is provided between the discharge liquid supply means and the droplet discharge head, and temporarily stores the discharge liquid supplied to the droplet discharge head;
An air amount adjusting means for adjusting the air in the reservoir tank to a predetermined amount;
Pressurizing means for adjusting the air amount in the reservoir tank with the air amount adjusting means and then pressurizing the air in the reservoir tank to overflow the discharge liquid on the nozzle surface of the droplet discharge head;
A liquid droplet ejection apparatus comprising: a pressurizing unit serving as a wiping unit for wiping the ejection liquid overflowing the nozzle surface. The air amount adjusting means includes
An openable and closable atmosphere communication channel for communicating the reservoir tank with the atmosphere;
A discharge liquid amount control means for introducing or deriving discharge liquid so that a predetermined amount of discharge liquid exists in the reservoir tank;
2. The discharge liquid amount control means adjusts the liquid volume of the discharge liquid in the reservoir tank to a predetermined liquid volume in a state where the air communication flow path is opened, and then closes the air communication flow path. Droplet discharge device. The pressurizing means is
3. The droplet discharge device according to claim 1, wherein after adjusting the air amount in the reservoir tank by the air amount adjusting means, the inside of the reservoir tank is pressurized by injecting a predetermined amount of air into the reservoir tank. . The pressurizing means is
3. The pressure of the reservoir tank according to claim 1, wherein after adjusting the amount of air in the reservoir tank by the air amount adjusting means, the discharge liquid supply means further injects discharge liquid into the reservoir tank and pressurizes the reservoir tank. Droplet discharge device.

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