JP2000289222A - Liquid ejection recording apparatus, liquid supply method, liquid removing method, and liquid replacing method for the liquid ejection recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable replacement of different kinds of liquids in a liquid supply system of a liquid ejection recording apparatus so as to enable use of plural kinds of liquid in an apparatus. SOLUTION: A main tank 2 and a sub tank 3 are connected via a main tank tube 32 and a main tank sub tank tube 65. The sub tank 3 and a retaining tank 33 are connected via a sub tank retaining tank tube 34. The retaining tank 33 and an ejection head part 1 are connected via a retaining tank tube 26, an air buffer 49 and a liquid ejection head supply tube 20. The sub tank 3 is connected with the air buffer 49 via a sub tank tube 21. In this case, for removing an ink in an ink path, the inside of the sub tank 3 is made to be in a positive pressure or a negative pressure so as to collect the ink in the ink path between the sub tank 3 and the air buffer 49. The collected ink is poured into the main tank 2 through the main tank sub tank tube 65.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid discharge recording apparatus for performing recording on a recording medium by discharging a liquid toward the recording medium, a liquid supply method for the liquid discharge recording apparatus, and a liquid discharge recording apparatus. The present invention relates to a liquid draining method and a liquid replacement method of a liquid discharge recording apparatus.

[0002]

2. Description of the Related Art A technique relating to the supply of liquid through a liquid supply path is used in various fields. As one example, a liquid discharge recording apparatus which discharges ink droplets from a recording head to perform recording on a recording medium. Is an ink jet recording apparatus.

Since an ink jet recording apparatus performs recording by discharging ink, it is necessary to constantly supply ink consumed by discharging to a recording head. As a method of supplying ink to the recording head, the present applicant has filed a liquid replenishing method, a liquid supply device, and a liquid discharge recording device disclosed in Japanese Patent Application Laid-Open No. 10-6521.

In the ink jet recording apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 10-6521, the inside of the sub-tank is a sealed space, and the ink in the main tank is supplied to the sub-tank while the pressure in the sub-tank is reduced by a negative pressure generating pump. Thus, the supply of the liquid is performed smoothly.

However, the above-mentioned Japanese Patent Application Laid-Open No. H10-65
In the ink jet recording apparatus disclosed in JP-A-21, when the remaining amount of ink in the sub-tank decreases during recording by the discharge head unit, the sub-tank is used as a closed space to supply ink to the sub-tank. The supply of ink to the unit must be interrupted. Therefore, after printing has been performed for a fixed amount by the ejection head unit, the printing must be interrupted and the ink must be supplied to the sub-tank.

[0006] In contrast to such an ink jet recording apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 10-6521, the present applicant filed a Japanese Patent Application No. 10-63473. A liquid ejection recording apparatus in which the supply of ink is not interrupted, and a liquid supply method of the liquid ejection recording apparatus are proposed. In the inkjet recording apparatus, a holding tank is arranged in an ink flow path between a sub tank and a discharge head unit, and the ink to be supplied to the discharge head unit is temporarily held in the holding tank. This allows the ink in the holding tank to be supplied to the ejection head unit when the ink from the main tank is supplied to the sub tank while reducing the pressure in the sub tank with the inside of the sub tank as a closed space, so that the ink in the ejection head unit The liquid can be supplied stably without interruption of the supply of the liquid.

In the current market, the demand for recording quality of an image recording apparatus tends to be further increased, and the recording quality of a liquid discharge recording apparatus includes not only image quality but also weather resistance.
What has excellent water resistance is required. Pigment inks are superior to dye inks as inks that can provide high recording quality, but dye inks are currently superior in terms of image quality.

[0008]

However, the conventional ink jet recording apparatus and the present invention are disclosed in Japanese Patent Application No. 10-63.
In the ink jet recording apparatus filed in Japanese Patent Application No. 473, when ink is supplied into the ink supply system, all the ink in the supply system cannot be drained due to the configuration of the ink supply system. There is a problem that it is impossible. Therefore, it is impossible to use a plurality of types of inks in a single ink jet recording apparatus so that they can be exchanged and used separately, and it is impossible to use a plurality of inks depending on the application such as image quality priority or weather resistance and water resistance priority. It was impossible to use different kinds of inks properly. Further, even when the same type of ink is used, when a plurality of color inks are used, a combination of cyan, magenta, yellow, black, light cyan, and light magenta can be used to obtain cyan, magenta, yellow, black, orange, blue, and green. It has not been possible to replace the ink with a special color like a combination, or to replace a reactive ink with a dispersible ink.

An object of the present invention is to make it possible to exchange different types of liquids in a liquid supply system of a liquid discharge recording apparatus, thereby enabling a single liquid discharge recording apparatus to selectively use a plurality of types of liquids. It is an object of the present invention to provide a possible liquid discharge recording apparatus, a liquid supply method of the liquid discharge recording apparatus, a liquid draining method in the liquid discharge recording apparatus, and a liquid replacement method of the liquid discharge recording apparatus.

[0010]

In order to achieve the above object, the present invention provides a discharge head unit for performing recording on a recording medium by discharging a liquid toward the recording medium, and the discharge head unit. A holding tank for holding ink to be supplied to
A sub-tank holding an ink to be supplied to the ejection head unit or the holding tank and having an air introduction passage capable of introducing air, a main tank for holding a liquid to be supplied to the sub-tank, and a liquid in the holding tank. A first supply path for supplying the liquid to the discharge head unit, and a liquid in the sub-tank having one end connected to the middle of the first supply path and the other end connected to the sub-tank. A second supply path for supplying the liquid in the sub-tank to the holding tank,
One end is connected to the upper part of the sub tank, and a pressure generating means for generating a pressure for making the inside of the sub tank a positive pressure, and a pressure for generating a pressure for making the inside of the sub tank a negative pressure,
A third supply path for supplying the liquid in the main tank to the sub tank, the other end being disposed at a lower part in the main tank, one end being connected to an upper part of the main tank, and the other end being A fourth supply path disposed at a lower part in the sub tank and for feeding the liquid in the sub tank into the main tank.

In addition, the apparatus further includes a carriage on which the discharge head is mounted and reciprocates, and a housing on which the carriage is mounted, wherein the holding tank, the sub tank, and the main tank are mounted on the housing. Is preferred.

Further, the flow path resistance of the first and second supply paths is smaller than the flow path resistance of the third supply path, and the pressure generating means for generating a positive pressure or a negative pressure in the sub-tank includes: It is preferable to use a pump that makes the inside of the sub-tank a positive pressure or a negative pressure by forward or reverse drive.

Further, the bottom in the sub-tank is inclined, and the tip of the second and fourth supply passages is disposed at the lowermost part in the sub-tank, and the bottom in the holding tank is inclined. It is preferable that the distal end of each of the first supply path and the supply path is disposed at a lowermost position in the holding tank.

Further, an end of the fourth supply path is detachably attached to the main tank,
It is preferable that an end of the fourth supply path on the main tank side further includes a waste liquid tank connectable in place of the main tank and for holding unnecessary liquid. Further, the discharge head section has an electrothermal converter that generates thermal energy used for discharging the liquid.

In the invention as described above, the liquid held in the main tank is supplied to the sub-tank through the third supply path, and the liquid held in the sub-tank is supplied to supply the liquid to the holding tank. It is supplied into the holding tank through the passage. When performing the operation of discharging the liquid from the discharge head unit, the liquid in the holding tank is usually the first liquid.
The liquid in the holding tank is also supplied to the discharge head through the second supply path and the first supply path on the side of the discharge head. Here, when the liquid in the sub-tank decreases, the pressure in the sub-tank is reduced by the pressure generating means to supply the liquid in the main tank to the sub-tank. Even if the supply of the liquid and the supply of the liquid from the sub tank to the holding tank are not performed, the liquid in the holding tank is supplied to the ejection head unit, and the supply of the liquid to the ejection head unit is not interrupted. Therefore, even when a liquid is supplied to the sub-tank with the inside of the sub-tank being a closed space, recording can be continuously performed on the recording medium without interrupting the recording operation of the ejection head unit. Further, in this liquid discharge recording apparatus, for example, when a pigment ink is used as the liquid to be discharged from the discharge head unit, the pigment ink is replaced with a dye ink, or the ink in the apparatus is replaced with another color ink. When the liquid in the apparatus is replaced with another liquid different from the liquid, the pressure in the sub-tank is set to a positive pressure or a negative pressure by the pressure generating means, so that the liquid in the liquid supply path between the sub-tank and the discharge head section is formed. The liquid can be collected in the sub tank, and the collected liquid in the sub tank can be sent into the main tank through the fourth supply path. When the liquid in the sub-tank is fed into the main tank, the liquid in the sub-tank flows into the main tank through the fourth supply path by setting the inside of the sub-tank to a closed space and making the pressure in the sub-tank positive by the pressure generating means. . Therefore, almost all of the liquid in the liquid discharge recording apparatus can be drained, and the cleaning liquid can be supplied to the supply path and the tank, and the tank and the supply path can be cleaned with the cleaning liquid. It becomes possible to use a plurality of types of liquids such as ink in the recording apparatus. As a result, it is possible to obtain a liquid discharge recording apparatus in which a plurality of types of ink can be selectively used depending on the use of the user.
Here, the bottom surface in the sub-tank is inclined, and the front ends of the second and fourth supply paths are disposed at the lowermost portion in the sub-tank. By arranging the first supply path and the leading end of the supply path, all of the liquid inside the liquid supply system, such as in the sub tank and the holding tank, can be drained.

According to the present invention, there is provided a liquid supply method for a liquid discharge recording apparatus for supplying the liquid in the main tank to the discharge head in the liquid discharge recording apparatus described above. The atmosphere introduction passage, the second supply passage, and the fourth supply passage are closed, and the inside of the sub tank is closed while the inside of the sub tank communicates with the inside of the main tank via the third supply passage. Forming a space, supplying the liquid in the main tank into the sub-tank through the third supply path by making the inside of the sub-tank a negative pressure by the pressure generating means, Measuring the amount, and bringing the inside of the sub-tank to atmospheric pressure by opening the air introduction passage based on the measurement result of the liquid amount in the sub-tank; A.

After the step of opening the air introduction passage provided in the sub-tank and setting the inside of the sub-tank to atmospheric pressure, a step of closing the air introduction passage, and a step of closing the second supply path. Closing the fourth supply path, closing the third supply path, and causing the pressure in the sub-tank to be positive by the pressure generating means, thereby causing the liquid in the sub-tank to pass through the supply path. Supplying to the holding tank, opening the air introduction passage to make the inside of the sub tank atmospheric pressure, opening the second supply passage, and opening the fourth supply passage And a step of opening the third supply path.

Further, after the step of opening the atmosphere introduction passage provided in the sub-tank to make the inside of the sub-tank atmospheric pressure, the step of closing the atmosphere introduction passage, and the step of holding the liquid in the sub-tank to the holding tank Closing the supply passage for supplying the first supply passage, closing a portion of the first supply passage from a connection portion with the second supply passage to the discharge head portion, A step of closing the supply path, a step of closing the third supply path, and a step in which the pressure in the sub tank is reduced to a negative pressure by the pressure generating means, thereby causing the liquid in the holding tank to pass through the first supply path. Feeding into a portion between the connection portion with the second supply passage and the holding tank, opening the air introduction passage to make the inside of the sub tank atmospheric pressure, and opening the supply passage When A step of opening the fourth supply path, a step of opening the third supply path, and a part of the first supply path from a connection part with the second supply path to the ejection head unit And supplying the liquid from the first and second supply paths to the discharge head by applying a negative pressure to the inside of the discharge head, and the discharge head from outside the discharge head. Sucking the liquid in the part.

According to the invention as described above, in a liquid discharge recording apparatus capable of selectively using a plurality of types of liquids, such as inks of different types and colors, as described above, a state in which the liquid is not filled in the liquid supply system is provided. Alternatively, the liquid supply operation can be performed in a state where the liquid in the discharge head is consumed by discharging the liquid from the discharge head.

Further, the present invention provides a liquid discharging method in a liquid discharge recording apparatus for discharging liquid in a liquid supply path from the main tank to the discharge head in the liquid discharging recording apparatus described above, Closing the atmosphere introduction passage provided in the sub-tank, closing the supply passage for supplying the liquid in the sub-tank to the holding tank, and closing the second supply of the first supply passage. A step of closing a part from a connection part with a passage to the discharge head unit, a step of closing the fourth supply path, a step of closing the third supply path, and the step of generating the pressure in the sub tank. Means for holding the liquid in the sub-tank through the second supply passage and the first supply passage through a portion from a connection portion of the second supply passage to the holding tank. Sending into the tank, opening the supply passage, closing the second supply passage, and causing the pressure in the sub-tank to be a negative pressure by the pressure generating means to reduce the liquid in the holding tank. Feeding the sub-tank through the supply passage, closing the supply passage, opening the fourth supply passage, and applying a positive pressure to the sub-tank by the pressure generating means. Feeding the liquid inside the main tank through the fourth supply path, closing the fourth supply path, opening the third supply path, and providing the first supply path Opening a portion from a connection portion with the second supply path to the ejection head portion, and sucking a liquid in the ejection head portion from outside the ejection head portion, A step of the inside of the sub tank to atmospheric pressure by opening the air introduction passage, said second
Opening the supply path, opening the supply path, and opening the fourth supply path.

In the above invention, the air introduction passage provided in the sub-tank, the supply passage from the sub-tank to the holding tank, the portion of the first supply passage from the connection portion with the second supply passage to the discharge head portion, By closing the fourth supply path and the third supply path and making the inside of the sub-tank a positive pressure, the part of the first supply path in the sub-tank from the holding tank to the connection part with the second supply path And the liquid in the second supply path are all sent into the holding tank. Next, the supply passage is opened, the second supply passage is closed, and the pressure in the sub-tank is set to a negative pressure, so that almost all the liquid in the holding tank is sent into the sub-tank. Next, the supply passage is closed, the fourth supply passage is opened, and the pressure in the sub-tank is made positive, whereby the liquid in the sub-tank is fed into the main tank. Thereby, all of the liquid in the liquid supply path from the main tank to the connection between the first and second supply paths is collected in the main tank. Next, the portion of the first supply path from the connection portion with the second supply path to the discharge head section is opened, and the liquid in the discharge head section is sucked from the outside of the discharge head section to thereby obtain the first supply path. The liquid in the portion of the passage from the connection portion with the second supply passage to the ejection head portion and the liquid in the ejection head portion are drained. By these operations, all of the liquid in the liquid supply path from the main tank to the ejection head unit and the liquid in the ejection head unit can be drained.

Further, the present invention relates to a liquid discharging method in a liquid discharge recording apparatus for discharging liquid in a liquid supply system path from the main tank to the discharge head in the liquid discharging recording apparatus described above, Closing the atmosphere introduction passage provided in the sub-tank, closing the supply passage for supplying the liquid in the sub-tank to the holding tank, and closing the second supply of the first supply passage. A step of closing a part from a connection part with a passage to the discharge head unit, a step of closing the fourth supply path, a step of closing the third supply path, and the step of generating the pressure in the sub tank. The first supply path is made negative by means of
A step of sending the liquid inside the portion from the holding tank to the connection portion with the second supply path and the liquid in the second supply path into the sub tank, and a step of closing the second supply path; Opening the fourth supply path, and causing the pressure in the sub-tank to be positive by the pressure generating means to cause the liquid in the sub-tank to flow through the second supply path and the first supply path. Feeding into the holding tank through a portion from the connection portion of the second supply path to the holding tank, opening the second supply path, and closing the fourth supply path; Opening the supply passage, closing the second supply passage, and applying a positive pressure to the sub-tank by the pressure generating means to cause the liquid in the sub-tank to pass through the fourth supply passage. Mainta Feeding the liquid into the sub-tank, closing the supply passage, opening the fourth supply passage, and applying a positive pressure to the sub-tank by the pressure generating means to reduce the liquid in the sub-tank. Feeding the fourth supply path into the main tank, closing the fourth supply path, opening the third supply path, and removing the second supply path from the second supply path. Opening a portion from the connection portion with the supply path to the ejection head portion, sucking the liquid in the ejection head portion from outside of the ejection head portion, and opening the atmosphere introduction passage to open the sub-tank. To the atmospheric pressure, the step of opening the second supply path, the step of opening the supply path, and the step of opening the fourth supply path.

In the above invention, the air introduction passage provided in the sub-tank, the supply passage from the sub-tank to the holding tank, the portion of the first supply passage from the connection portion with the second supply passage to the discharge head portion, By closing the fourth supply path and the third supply path and creating a negative pressure in the sub-tank, at least the liquid in the second supply path, the second supply path of the first supply path, All the liquid inside the portion from the connection portion to the holding tank is sent into the sub tank. next,
By closing the second supply path, opening the fourth supply path, and applying a positive pressure to the sub tank, almost all of the liquid in the sub tank is sent into the main tank. Next, the second supply path is opened, the fourth supply path, the supply path, and the second supply path are closed, and the pressure in the sub tank is set to a negative pressure, so that the liquid in the holding tank passes through the supply path. It is sent into the sub tank. Next, the supply passage is closed, the fourth supply passage is opened, and the pressure in the sub-tank is made positive, whereby the liquid in the sub-tank is fed into the main tank. Thereby, all of the liquid in the liquid supply path from the main tank to the connection between the first and second supply paths is
Collected in the main tank. Next, in the first supply path,
The portion from the connection portion with the second supply path to the ejection head portion is opened, and the liquid in the ejection head portion is sucked from the outside of the ejection head portion, whereby the first supply passage and the second supply passage are connected. The liquid in the portion from the connection portion to the ejection head portion and the liquid in the ejection head portion are drained. By these operations, all of the liquid in the liquid supply path from the main tank to the ejection head unit and the liquid in the ejection head unit can be drained.

Further, according to the present invention, there is provided a liquid discharge recording apparatus as described above, wherein the liquid is supplied from the main tank into the liquid supply path from the main tank to the discharge head section, and into the discharge head section. A step of draining liquid from within the liquid supply path and the inside of the ejection head portion using any one of the liquid draining methods, and the main tank,
Replacing the cleaning liquid with the cleaning tank containing the cleaning liquid, supplying the cleaning liquid into the liquid supply path by the liquid supply method of the liquid discharge recording apparatus, and applying the cleaning liquid in the liquid supply path to the liquid discharge recording Draining using any of the liquid draining methods in the apparatus, and the washing tank,
Replacing with a main tank that holds another liquid different from the liquid.

In the above invention, after the liquid in the main tank is supplied into the liquid supply path and the discharge head,
The liquid in the liquid supply path is collected in the main tank, the liquid in the discharge head is drained, the main tank is replaced with a cleaning tank containing the cleaning liquid, and the liquid supply path is cleaned with the cleaning liquid. By doing so, all the liquid previously in the liquid supply system is removed. next,
By exchanging the main tank and the cleaning tank for holding another liquid different from the liquid discharged from the liquid discharge recording apparatus, another liquid different from the discharged liquid can be used in the liquid discharge recording apparatus. Therefore, according to the liquid replacement method of such a liquid discharge recording apparatus, 1
It is possible to use a plurality of types of liquids such as inks in one liquid ejection recording apparatus, and as a result, it is possible to selectively use a plurality of types of inks according to the user's application.

[0026]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a top view of an ink jet recording apparatus which is a liquid discharge recording apparatus according to a first embodiment of the present invention. FIG. 2 is a front view of the ink jet recording apparatus shown in FIG. 1, and is a view of the ink jet recording apparatus viewed from the direction of arrow A shown in FIG.

In the ink jet recording apparatus of this embodiment, as shown in FIGS. 1 and 2, a housing 24 is provided with side plates 22 and 23 facing each other. Side plate 2
2, one end of each of the main scanning rail 7 and the carriage stay 4 which are parallel to each other is attached.
The other ends of the main scanning rail 7 and the carriage stay 4 are attached. The carriage 16 is slidably supported by the main scanning rail 7 and the carriage stay 4 in the direction of arrow X shown in FIG. The carriage 16 is equipped with six ejection heads 1 for six colors of cyan, magenta, yellow, black, cyan light color, and magenta light color.

Each ejection head unit 1 has a nozzle unit for ejecting liquid ink to a recording medium such as paper or film. Each nozzle unit is provided with an electrothermal converter (heater) that generates thermal energy for ink ejection. Ink is supplied into the ejection head unit 1 by capillary action in the nozzle unit, and the ink in the nozzle unit is supplied to the tip end surface (hereinafter, referred to as “nozzle surface”) of the nozzle unit.
) To form a meniscus to keep the nozzle portion filled. In this state, when electricity is supplied to the electrothermal transducer, the ink on the electrothermal transducer is heated to cause a bubbling phenomenon, and the foaming energy causes ink droplets to be ejected from the nozzle toward the recording medium. You.

Further, the ejection head unit 1 is provided with a drive board for driving the ejection head unit 1. A drive board of the ejection head unit 1 is connected to a main board 27 attached to the housing 24 via a flexible cable 28. By transmitting an electric signal from the main board 27 to the drive board of the ejection head unit 1 through the flexible cable 28, the ejection timing of the ink of the ejection head unit 1 is controlled. On the other hand, the main scanning motor 8 is attached to one end of the casing 24, and the pulley 6 is attached to the other end of the casing 24. A belt 18 is hung on the main scanning motor 8 and the pulley 6, and the belt 18 runs as the main scanning motor 8 is driven. Belt 18
Is connected to a carriage 16. Therefore,
As the belt 18 runs, the carriage 16
It moves in the direction of arrow X shown in FIG.

The carriage 16 has six air buffers 49 corresponding to each of the six ejection head units 1. Each ejection head unit 1 is provided with an air buffer 49 and a head supply tube 20 corresponding to each ejection head unit 1.
Connected by A holding tank 33 for temporarily holding ink to be supplied to the ejection head unit 1 and a sub-tank 3 for temporarily holding ink to be supplied to the holding tank 33 are attached to an end of the housing 24 on the pulley 6 side. ing. Below the sub-tank 3 and the holding tank 33, a main tank 2 for storing ink to be supplied to the sub-tank 3 is attached as shown in FIG.

The inside of each of the holding tank 33, the sub tank 3 and the main tank 2 is divided into six chambers corresponding to each color ink. Each chamber of the holding tank 33 is connected to the corresponding air buffer 49 and the holding tank tube 26. Therefore, the first supply path for connecting the ejection head unit 1 and the holding tank 33 to supply the ink in the holding tank 33 to the ejection head unit 1 is:
It comprises a head supply tube 20, an air buffer 49 and a holding tank tube 26. An air buffer 49 is provided in a portion of the first supply path near the ejection head unit 1. Each chamber of the sub-tank 3 is connected to a corresponding air buffer 49 by a sub-tank tube 21 which is a second supply path. Each chamber of the sub tank 3 is connected to a corresponding chamber of the main tank 2 by a main tank tube 32 forming a third supply path.

One end of a bendable track 31 is fixed to the carriage 16 with screws. The other end of the caterpillar 31 is fixed to a portion of the housing 24 near the sub tank 3 and the holding tank 33 with screws. The inside of the caterpillar 31 is connected to the sub tank tube 2.
1 and the holding tank tube 26 pass through.

In the vicinity of the sub tank 3 and the main tank 2, a recovery system 25 composed of a cap and the like is provided as described later with reference to FIG. The ink path between the main tank 2 and the ejection head unit 1 and the detailed configuration in the liquid supply path will be described later.

As for the ink flow in the ink jet recording apparatus shown in FIGS. 1 and 2, ink is supplied from the main tank 2 to the sub tank 3 through the main tank tube 32. Thereafter, ink is supplied from the sub-tank 3 to the holding tank 33 through a sub-tank holding tank tube as a supply passage described later with reference to FIG.
Then, from the sub tank 3 through the sub tank tube 21 and from the holding tank 33 to the holding tank tube 2
The ink is supplied to the air buffer 49 through 6.
Ink is supplied from the air buffer 49 to the ejection head unit 1 through the head supply tube 20.

A paper feed roller 30, a sub-scanning roller 19 and a paper discharge roller 29 extending in a direction parallel to the moving direction of the carriage 16 are attached to the housing 24.
Paper feed roller 30, sub-scanning roller 19 and paper discharge roller 2
9 is rotatably supported by the side plate 22, and the other end of each of the paper feed roller 30, the sub-scanning roller 19, and the paper discharge roller 29 is rotatably supported by the side plate 23. The recording paper 15 as a recording medium is fed by the sub-scanning roller 19 and the ejection head 1
Is discharged onto the recording paper 15 to perform recording on the recording paper 15.

Next, the conveyance path of the recording medium in the ink jet recording apparatus of the present embodiment will be described with reference to FIG. FIG. 3 is a sectional view taken along line YY ′ of FIG.

First, when recording is performed on an easily bendable recording medium (hereinafter, referred to as recording paper 15) such as thin paper or film, as shown in FIG. It is inserted into the manual feed slot 71. The inserted recording paper 15 is sandwiched between two opposing manual feed rollers 5,
The sheet is conveyed in a direction toward the sub-scanning roller 19. The manual feed driven roller 36 is urged toward the sub-scanning roller 19, and the recording paper 15 that has reached the sub-scanning roller 19 is sandwiched between the sub-scanning roller 19 and the manual driven roller 36,
The sheet is conveyed in a direction toward the driven roller 37 near the ejection head unit 1. The driven roller 37 is urged toward the sub-scanning roller 19. The recording paper 15 that has reached the driven roller 37
Is transported sandwiched between the sub-scanning roller 19 and the driven roller 37, and the recording paper 15 passes below the nozzle surface of the ejection head unit 1. Thereafter, the recording paper 15 is conveyed while being sandwiched between the two facing paper discharge rollers 29, and is discharged from the paper discharge port 72.
From the ink jet recording apparatus.

On the other hand, when recording on a straight printed material 35 such as a plate material, thick paper, or a thick film that cannot be bent or is difficult to bend as a recording medium, the straight printed material 35 is inserted from the insertion slot 73. You. The inserted straight printed matter 35 is connected to the two sheet feed rollers 3 facing each other.
0 and is conveyed in the direction toward the sub-scanning roller 19. When the straight printed matter 35 reaches the sub-scanning roller 19, the straight printed matter 35 is conveyed while being sandwiched between the driven roller 37 and the sub-scanning roller 19, and the straight printed matter 35 is discharged from the nozzle surface of the ejection head unit 1. Pass below. Thereafter, the straight printed matter 35 is conveyed by being sandwiched between the two facing paper discharge rollers 29 and discharged from the paper discharge port 72 to the outside of the ink jet recording apparatus.

When the recording paper 15 or the straight print 35 is positioned below the discharge head 1, ink is discharged from the discharge head 1 to record the print on the recording paper 15 or the straight print 35. Is performed.

Next, referring to FIG.
The positional relationship among the sub tank 3, the holding tank 33, the air buffer 49, and the ejection head unit 1 will be described. FIG.
FIG. 3 is a sectional view of a main part of the ink jet recording apparatus shown in FIGS. 1 and 2.

As described above, as for the flow of ink in the ink jet recording apparatus, ink is supplied from the main tank 2 to the sub tank 3 through the main tank tube 32. Thereafter, ink is supplied from the sub tank 3 to the holding tank 33 through the sub tank holding tank tube 34. The sub tank holding tank tube 34 is provided with a sub tank holding tank valve 39 that closes the ink path between the sub tank 3 and the holding tank 33 by crushing the sub tank holding tank tube 34. And
Ink is supplied to the air buffer 49 from the sub tank 3 through the sub tank tube 21 and from the holding tank 33 through the holding tank tube 26. The head supply tube 20 is supplied from the air buffer 49 to the ejection head unit 1.
The ink is supplied through the.

As shown in FIG. 4, the sub-tank 3 and the holding tank 33 are lower than the nozzle surface of the discharge head 1, and the sub-tank 3 and the holding tank 33 are formed so that a meniscus is formed on the nozzle surface of the discharge head 1. A holding tank 33 is provided. Here, the sub-tank 3 and the holding tank 33 and the transport path 74 are located at substantially the same height, but as shown in FIGS. The sub-tank 3 and the holding tank 33 are attached to the transport path 74 or the transport path of the straight print 35 shown in FIG. 3 because the tanks are located outside the transport path of the recording medium. It is configured not to interfere.

Next, the configuration in the liquid supply path in the ink jet recording apparatus of this embodiment will be described with reference to FIG. FIG. 5 is a diagram showing an ink path of the ink jet recording apparatus shown in FIGS. As described above, the ink jet recording apparatus of the present embodiment uses inks of a plurality of colors, and ink paths are provided for each color. However, since each ink path is the same, FIG. Shows a path for one color ink.

As shown in FIG. 5, the main tank 2 and the sub tank 3 are connected by a main tank tube 32. A joint 54 having a hollow needle 56 such as an injection needle is attached to an end of the main tank tube 32 on the side connected to the main tank 2. The joint 54 is attached to a rubber stopper 55 provided on the upper part of the main tank 2, and the needle 56 penetrates the rubber stopper 55,
The inside of the needle 56 communicates with a tube 67 attached to the rubber stopper 55 on the main tank 2 side. Tube 67
Extends from the upper part of the main tank 2 to the lower part in the main tank 2, and the lower end of the tube 67 is arranged at the lowest part in the main tank 2. Therefore, the third ink for supplying the ink in the main tank 2 to the sub-tank 3
Is constituted by the tube 67, the needle 56, and the main tank tube 32. The other end of the main tank tube 32 is inserted into the sub tank 3, and a main tank valve 66 for closing the main tank tube 32 is mounted in the middle of the main tank tube 32.

A rod-shaped electrode A43, an electrode B44 and an electrode C45 are inserted into the sub-tank 3 from the upper end of the sub-tank 3 in order to detect the remaining amount of ink in the sub-tank 3. The electrode A43, the electrode B44, and the electrode C45 constitute a liquid level detecting unit for detecting the liquid level of the ink in the sub tank 3. By detecting the liquid level of the ink in the sub tank 3 at a predetermined height by the liquid level detecting means, the remaining amount of the ink in the sub tank 3 is detected.

The main tank 2 and the sub tank 3 are also connected by a main tank sub tank tube 65 which is a fourth supply path for feeding the ink in the sub tank 3 into the main tank 2. One end of the main tank sub tank tube 65 is connected to the upper part of the main tank 2, and the other end of the main tank sub tank tube 65 is inserted into the sub tank 3 from above the sub tank 3. Main tank Sub tank tube 65
The end on the side of the sub-tank 3 reaches the lowermost part in the sub-tank 3. This main tank sub tank tube 6
In the middle of 5, a main tank sub-tank valve 64 for closing the main tank sub-tank tube 65 is attached.

One end of the main tank sub-tank tube 65 has a joint having a hollow needle such as an injection needle, and a rubber stopper to which the joint is attached, similarly to the end of the main tank tube 32 on the main tank 2 side. It is detachably attached to the upper part of the main tank 2 via a. In addition, a main tank tube 32 and a main tank sub tank tube 6 are provided above the main tank 2.
5, apart from the joints and rubber stoppers attached to the end of the main tank 2 on the side of the main tank 2, similar to those joints and rubber stoppers are attached, and the main tank 2 is inserted through hollow needles provided in the joints. Is always in communication with the atmosphere. Therefore, on the upper part of the main tank 2, three joint structures each including a joint having a hollow needle and a rubber stopper are attached, and two of the three joint structures are the main tank 2 and the sub tank 3. Used to connect with
The remaining one joint structure is used for communicating the inside of the main tank 2 with the atmosphere. The three joint structures attached to the main tank 2 are detachable.

As shown in FIG. 5, the electrode A43 is inserted until the tip of the electrode A43 reaches the height indicated by (Q). The tips of the electrode B44 and the electrode C45 reach the height shown in (H), which is deeper than the height shown in (Q). The electrode A43, the electrode B44, and the electrode C45 are electrically connected to the main board 27 shown in FIGS. 1 and 2, respectively. By flowing a low current through each of the electrodes A43, B44, and C45, and detecting conduction between the electrodes via the ink that is a conductive substance, the amount of ink in the sub tank 3 is detected. Specifically, if the liquid level of the ink in the sub-tank 3 is lower than the height (H), the connection between the electrode B44 and the electrode C45 becomes non-conductive. Ink is supplied from the main tank 2 to the sub tank 3. If the liquid level of the ink in the sub-tank 3 is higher than the height of (Q), conduction between the electrode A43 and the electrode B45 is conducted, and when this is detected, the ink supply to the sub-tank 3 is stopped.

At a position above the sub-tank 3 at a height higher than the height indicated by (Q), an air introduction passage through which air can be introduced into the sub-tank 3 is provided. An air release valve 63 that is opened and closed by a drive source (not shown) is provided at the distal end. Atmospheric release valve 6
By controlling the opening / closing operation of the sub-tank 3, the air introduction passage of the sub-tank 3 can be closed or opened.

The holding tank 33 is adjacent to the sub tank 3. As will be described later, the bottom surfaces of the inside of the sub-tank 3 and the inside of the holding tank 33 are inclined to smoothly perform the operation of draining the ink in the ink path. Main tank subtank tube 65 and subtank tube 21 inserted into subtank 3 from above subtank 3
The tip of the holding tank tube 26 inserted into the holding tank 33 from the top of the holding tank 33 is located at the bottom of the holding tank 33.

The bottom surface of the sub tank 3 is connected to one end of a sub tank holding tank tube 34 serving as a supply passage, and the bottom surface of the holding tank 33 is connected to the other end of the sub tank holding tank tube 34. The bottom of the sub tank 3 and the bottom of the holding tank 33 are connected by the sub tank holding tank tube 34. The portion of the sub tank holding tank tube 34 on the holding tank 33 side is in direct communication with the lowermost portion in the holding tank 33. A sub-tank holding tank valve 39 is provided in the middle of the sub-tank holding tank tube 34. The sub-tank holding tank valve 39 is for closing the ink path between the sub-tank 3 and the holding tank 33 by crushing the sub-tank holding tank tube 34.

The sub tank 3 and the air buffer 49 are
It is connected via a sub tank tube 21. One end of the sub-tank tube 21 on the side of the sub-tank 3 reaches the lowermost portion in the sub-tank 3 as described above, and is arranged at a position lower than the lower ends of the electrodes B44 and C45. An end of the sub tank tube 21 on the air buffer 49 side is inserted into the air buffer 49 from the upper end of the air buffer 49.

As shown in FIG. 5, the bottom of the air buffer 49 is inclined, and
One end of each of the holding tank tube 26 and the head supply tube 20 is connected to the vicinity of the lowermost part in the inside 9. With such a configuration, the ink easily flows, and the ink removing operation described later can be performed smoothly.

The holding tank 33 and the bottom of the air buffer 49 are connected by the holding tank tube 26. The end of the holding tank tube 26 on the holding tank 33 side is inserted into the holding tank 33 from the upper portion of the holding tank 33 as described above, and the end surface of the holding tank tube 26 reaches the lowermost portion in the holding tank 33. I have.

The bottom of the air buffer 49 and each ejection head 1 are connected by a head supply tube 20. A buffer valve 46 is provided in the middle of each head supply tube 20.

The cap 47 for capping the discharge port surface of the discharge head 1 is connected to the waste ink tank 52 by a suction tube 65. The suction tube 65 is provided with a suction pump 48. A tube pump is used as the suction pump 48. In a state where the ejection head unit 1 is capped by the cap 47, the suction pump 48
Is driven, the ink in the ejection head unit 1 is sucked through the cap 47, and the sucked ink is stored in the waste ink tank 52 through the suction tube 65.

Further, the waste ink tank 52 and the sub tank 3 are connected by a pump tube 42.
One end of the pump tube 42 is inserted into the sub tank 3 from above the sub tank 3, and one end of the pump tube 42 is arranged at a position higher than the height of the lower end of the electrode A 43. The pump tube 42 is provided with a supply pump 66 which is a pressure generating means for generating a pressure for making the inside of the sub tank 3 positive and a pressure for making the inside of the sub tank 3 negative. As the supply pump 66, a tube pump driven forward or backward as described later is used.

Each of the suction pump 48 and the supply pump 66 has a rotor, and the pump is driven by rotating the rotor of each pump by a pump motor (not shown). By rotating the rotor of the suction pump 48 in the direction indicated by the arrow S and driving the suction pump 48, the air and ink in the suction tube 65 are removed.
It moves in the direction indicated by arrow I. When the rotor of the supply pump 66 is rotated in the direction indicated by the arrow T and the supply pump 66 is driven to rotate forward, the air and ink in the pump tube 42 move in the direction indicated by the arrow K. Conversely, when the rotor of the supply pump 66 is rotated in the direction shown by the arrow U to drive the supply pump 66 in the reverse direction, the air and ink in the pump tube 42 are
It moves in the direction indicated by arrow R.

The flow resistance when the ink in the holding tank 33 flows into the sub-tank 3 through the holding tank tube 26, the air buffer 49 and the sub-tank tube 21 is as follows. Is smaller than the flow path resistance when flowing through.

Next, the operation of supplying ink from the main tank 2 to the sub tank 3 will be described with reference to FIG. FIG. 6 is a flowchart showing a sequence of an ink supply operation from the main tank 2 to the sub tank 3.

First, the atmosphere release valve 63, the sub tank valve 3
8. Drive the sub tank holding tank valve 39 and the main tank sub tank valve 64 to close each valve (S10
1, S102, S103, S104), the inside of the sub tank 3 is sealed. Then, the supply pump 41 is driven to rotate forward (S105), and the air in the pump tube 42 is sucked in the direction of the arrow R to make the inside of the sub tank 3 a negative pressure.
The ink in the main tank 2 is transferred to the main tank tube 32
Through the sub-tank 3.

Due to such an ink supply operation from the main tank 2 to the sub tank 3, when both the electrode A43 and the electrode B44 electrically connected to the main board 27 shown in FIGS. 1 and 2 come into contact with the ink. Since the ink is a conductive substance, electricity flows between the electrode A43 and the electrode B44, it is detected that the sub tank 3 is filled with the ink (S106), and a detection signal is sent to the main board 27. As a result, an instruction to stop the supply pump 41 is issued from the main board 27, and the supply pump 41 stops (S107).

Next, the atmosphere release valve 63, the sub tank valve 3
8. Open the sub tank holding tank valve 39 and the main tank sub tank valve 64 (S108, S109, S110,
In S111), the ink in the sub tank 3 flows into the holding tank 33 through the sub tank holding tank tube 34 due to the weight of the ink. At this time, the ink in the sub-tank 3 flows into the holding tank 33 until the ink level in the sub-tank 3 and the ink level in the holding tank 33 become the same.

Here, the sub-tank holding tank tube 3
When ink and air (bubbles) are mixed in the ink tank 4, ink may not flow easily or may not flow in the sub tank holding tank tube. In this case, an operation of forcibly supplying the ink in the sub tank 3 into the holding tank 33 through the sub tank holding tank tube 34 is performed.

Next, the operation of forcibly supplying ink from the sub tank 3 to the holding tank 33 will be described with reference to FIG. FIG.
9 is a flowchart showing a sequence of an operation for forcibly supplying ink to the printer.

First, the atmosphere release valve 63 and the sub tank valve 3
8. The main tank sub-tank valve 64 and the main tank valve 66 are closed (S112, S113, S114, S1
15) After that, the rotor of the supply pump 41 is rotated in the direction of arrow T to drive the supply pump 41 in the reverse direction (S11).
6, S117), the air in the pump tube 42 is sent in the direction of arrow K. As a result, the inside of the sub-tank 3 becomes positive pressure, and the ink in the sub-tank 3 is pushed out into the sub-tank holding tank tube 34, and as a result, the air (bubbles) existing in the sub-tank holding tank tube 34
Is pushed out into the holding tank 33. Thereafter, the supply pump 41 is stopped (S118), and the atmosphere release valve 63, the sub tank valve 38, the main tank sub tank valve 64, and the main tank valve 66 are opened (S119, S120, S12).
1, S122). As a result, the inside of the sub-tank holding tank tube 34 is filled with ink, and the ink level in the sub-tank 3 is maintained until the level of the ink level in the sub-tank 3 becomes equal to the level of the ink level in the holding tank 33. The holding tank 3 through the sub tank holding tank tube 34
Flows into 3. Further, the holding tank 33 has an atmosphere opening port 51.
The air (bubbles) pushed out from the sub tank holding tank tube 34 into the holding tank 33 can be released into the atmosphere from the atmosphere opening port 51, so that the inside of the holding tank 33 is always maintained at the atmospheric pressure. Dripping.

The height of the ink level in the sub tank 3
After the liquid level of the ink in the holding tank 33 becomes the same, if the liquid level of the ink in the sub-tank 3 is at a position not in contact with the electrodes B44 and C45 in the sub-tank 3, FIG. An operation of supplying ink from the main tank 2 to the sub tank 3 is performed as in the sequence shown in the flowchart of FIG. In this case, since there is no ink between the electrodes B44 and C45 electrically connected to the main board 27, no electricity flows between the electrodes B44 and C45. As shown in the flowchart of FIG.
When it is detected that electricity does not flow between the electrode 44 and the electrode C45 (S123), an instruction signal for starting the ink supply operation is sent from the main board 27 again, and the main tank 2 described with reference to FIG. The operation of supplying ink to No. 3 is performed again.

By repeating the above-described ink supply operation from the main tank 2 to the sub-tank 3, the heights of the ink levels in the sub-tank 3 and the holding tank 33 are as shown in FIG. And (H).

Next, the operation of supplying ink from the holding tank 33 to the air buffer 49 will be described with reference to FIG. FIG. 9 shows the state of the holding tank 33 and the air buffer 4.
9 is a flowchart showing a sequence of an ink supply operation to the ink jet head 9 and an ink supply operation from the air buffer 49 to the ejection head unit 1.

First, the atmosphere release valve 63, the sub tank holding tank valve 39, the buffer valve 46, the main tank sub tank valve 64, and the main tank valve 66 are closed (S124, S1).
25, S126, S127, S128). Thereafter, the supply pump 41 is driven to rotate forward (S129, S130), and the air in the pump tube 42 is sent in the direction of arrow R to make the pressure in the sub tank 3 negative. Thereby, the inside of the sub tank tube 21 together with the sub tank 3 becomes negative pressure,
As a result, the inside of the air buffer 49 and the inside of the holding tank tube 26 become negative pressure. Then, the ink in the holding tank 33 is supplied into the air buffer 49 through the holding tank tube 26, and after the liquid level of the ink in the air buffer 49 reaches a height in contact with the tip of the sub tank tube 21, The ink in the air buffer 49 enters the sub tank 3 through the sub tank tube 21.

At this time, the main tank tube 3
Since the inside of the tank 2 also has a negative pressure, the supply of ink from the main tank 32 to the sub tank 3 is also performed. Then, after driving the supply pump 41 for a predetermined time, the supply pump 41 is stopped (S131).

Thereafter, the atmosphere release valve 63, the sub tank holding tank valve 33, the main tank sub tank valve 64, and the main tank valve 66 are opened (S132, S133, S13).
4, S135).

Here, as described above, the ink in the holding tank 33 is filled with the holding tank tube 26 and the air buffer 4.
9 and the flow path resistance when flowing through the sub tank tube 21 is smaller than the flow path resistance when the main flow in the main tank 2 flows through the tank tube 32, so that the ink in the holding tank 33 can be reliably transferred to the air buffer. 49 can be supplied.

Next, the operation of supplying ink from the air buffer 49 to the ejection head unit 1 will be described with reference to the flowchart of FIG.

First, the ejection head 1 is capped with the cap 47 (S138). And the suction pump 48
Is driven (S137), and the air in the suction tube 9 is moved in the direction of the arrow I, so that the inside of the cap 47, the inside of the nozzle of the ejection head unit 1, and the inside of the liquid flow path are made negative pressure. Next, the buffer valve 46 is opened (S138).
Thus, the ink in the air buffer 49 is supplied to the ejection head unit 1, and the nozzles in the ejection head unit 1 are filled with the ink. Next, the suction pump 48 is stopped (S13).
9) After that, the cap 47 is separated from the ejection head unit 1 and opened (S140). At this time, since a meniscus is formed in the nozzles in the ejection head unit 1, the difference J in height between the nozzle surface 59 of the ejection head unit 1 and the liquid surface of the ink in the sub tank 3 and the holding tank 33 is determined. Can be held in the nozzles of the ejection head unit 1.
Here, the ink sucked into the cap 47 passes through the suction tube 9 and is stored in the waste liquid tank 52.

By supplying ink to the nozzles of the ejection head unit 1 in this manner, it becomes possible to eject ink from the ejection head unit 1.

Next, the operation of supplying ink from the main tank 2 to the sub tank 3 when recording is performed on the recording medium from the ejection head unit 1 will be described.

In the ink jet recording apparatus of this embodiment, when the ink in the air buffer 49 is supplied to the ejection head unit 1 during the operation of ejecting the ink from the ejection head unit 1, the ink in the holding tank 33 is held. The ink is supplied to the air buffer 49 through the tank tube 26, and the ink in the sub tank 3 is supplied to the air buffer 49 through the sub tank tube 21. Here, in the ink jet recording apparatus according to the present embodiment, even when the ink is supplied from the main tank 2 to the sub tank 3, the holding tank 3
The ink in 3 can be supplied to the air buffer 49 through the holding tank tube 26. During the operation of supplying ink from the main tank 2 to the sub-tank 3, since the buffer valve 46 is open, the head supply tube 2 flows from the air buffer 49 to the ejection head unit 1.
0 to supply the ink, and
The ink can be supplied from the holding tank 33 to the air buffer 49 via the holding tank tube 26. Therefore, even while the ink is being supplied from the main tank 2 into the sub-tank 3, it is possible to continue recording on the recording medium from the discharge head unit 1 without interrupting the supply of the ink to the discharge head unit 1. is there.

Further, when ink is not supplied from the main tank 2 to the sub tank 3, even when the recording medium is being
When the ink inside runs out, the main tank 2 can be replaced and the main tank 2 filled with ink can be mounted on the housing 24 of the inkjet recording apparatus. Next, as a liquid discharging method of the liquid discharge recording apparatus which is the gist of the present invention, an ink discharging method of the ink jet recording apparatus will be described with reference to FIGS. 5, 10 and 11. FIG.
FIG. 10 is a flowchart showing a sequence of an ink removing operation of the ink jet recording apparatus, and FIG. 11 is a flowchart showing a sequence of an operation subsequent to the suction operation by the cap shown in FIG.

When the ink is filled in the ink path, the atmosphere release valve 63, the sub tank holding tank valve 39, the buffer valve 46, the main tank sub tank valve 64
Then, the main tank valve 66 is driven to close each valve. (S141, S142, S143, S144
S145) Next, the rotor of the supply pump 41 is rotated in the direction of arrow T in FIG. 5 to drive the supply pump 41 in the reverse direction for a certain time (S146, S147), and the pump tube 4
The inside of the sub-tank 3 is made positive pressure by sending the air in 2 in the direction of arrow K. As a result, all of the ink inside the sub-tank 3, the sub-tank tube 21, the air buffer 49, and the holding tank tube 38 are all sent into the holding tank 33. Therefore, by such an operation, almost all the ink in the sub tank 3, the sub tank tube 21, the air buffer 49, and the holding tank tube 38 is collected in the holding tank 33.

After the supply pump 41 is driven to rotate in the reverse direction for a certain period of time, substantially all of the ink in the sub tank 3 is fed into the holding tank 33, the sub tank holding tank valve 39 is opened (S148), and the sub tank valve 38 is opened. Close (S149). Next, the rotor of the supply pump 41 is
By rotating the supply pump 41 forward for a certain period of time by rotating in the direction of arrow U (S150, S151),
The inside of the sub tank 3 is made negative pressure. Thus, the ink in the holding tank 33 and the sub tank holding tank tube 34 is sucked into the sub tank 3 through the sub tank holding tank tube 34.

After a certain period of time has elapsed since the start of the normal rotation drive of the supply pump 41, after all the ink in the holding tank 33 and the sub tank holding tank tube 34 has been sucked into the sub tank 3, the operation of the supply pump 41 is started. Before stopping the operation, the sub tank holding tank valve 39 is closed (S1).
52). By closing the sub-tank holding tank valve 39 before stopping the forward rotation of the supply pump 41 and disposing the sub-tank holding tank valve 39 near the bottom of the sub-tank 3, the sub-tank holding tank valve 39 is closed. It is possible to make almost no residual ink remain in the tube 34.

Next, in this state, the main tank sub-tank valve 64 is opened (S153), and the rotor of the supply pump 41 is rotated in the direction of the arrow T in FIG. S155) The inside of the sub tank 3 is set to a positive pressure. Thereby, the ink in the sub tank 3 is sent into the main tank 2 through the main tank sub tank tube 65.

By the above operation, ink other than the ink in the main tank tube 32 and the head supply tube 20 is sent to the main tank 2.

Next, with the supply pump 41 being driven in reverse, the main tank sub-tank valve 64 is closed (S15).
6) Then, the main tank valve 66 is opened (S157), and the pressure inside the sub tank 3 is made positive. Thereby, the remaining ink in the main tank tube 32 is sent into the main tank 2.

Next, the supply pump 41 is stopped from that state (S158), and the buffer valve 46 is opened (S159).
Next, when suction is performed by the cap 47 (S160),
The remaining ink in the head supply tube 20 and the discharge head unit 1 is sucked into the waste liquid tank 52.

Thereafter, the atmosphere release valve 63 and the sub tank valve 3
8. Open the sub tank holding tank valve 39 and the main tank sub tank valve 64 (S161, S162, S16
3, S164). In the ink removal operation described above,
Since the bottom of the sub tank 3 is inclined, the sub tank 3
All the ink in the main tank sub tank tube 6
5, the ink is pushed out to the main tank 2 and the ink does not accumulate in the sub tank 3.

By the above operation, all the ink in the ink path shown in FIG. 5 has been drained, and the ink drained from the ink path is collected in the main tank 2 or the waste ink tank 52. Therefore, according to the configuration of the ink path and the ink removing method as described above, there is an advantage that most of the remaining ink in the ink flow path can be reused.

Next, an operation of cleaning the inside of the ink path after the ink in the ink path is drained will be described.

First, the main tank 2 to the main tank tube 32 and the main tank sub tank tube 65
To remove the main tank 2 from the housing 24 of the inkjet recording apparatus. Next, instead of the main tank 2, a cleaning tank previously filled with a cleaning liquid is attached to the housing 24, and the cleaning liquid in the cleaning tank is filled into the ink path according to the sequence shown in FIG.

Thereafter, the cleaning liquid is drained from the ink path according to the sequence shown in FIG.

Here, pure water is used as the cleaning liquid, and there is no electrolyte in the sub tank 3 for detection by the electrodes A43, B44 and C45.
Sub tank 3 in steps S104 and S105 in FIG.
Is supplied by driving the supply pump 41 for a predetermined time. At this time,
By driving the supply pump 41 until the level of the pure water in the sub-tank 3 becomes higher than the line (Q) shown in FIG. 5, the pure water adheres to the inner wall of the sub-tank 3 and remains in the sub-tank 3. Ink can be washed without leaking by the washing liquid.

In the operation of cleaning the inside of the ink path, the main tank sub-tank tube 65 is connected to the waste ink tank 52 which is a waste liquid tank for discharging unnecessary ink or cleaning liquid after cleaning. The subsequent cleaning liquid may be made to flow into the waste ink tank 52 through the main tank sub tank tube 65.

After the sequence shown in FIGS. 10 and 11 has been completed, the cleaning tank attached to the housing 24 is replaced with the main tank 2 holding another ink different from the ink withdrawn from the ink supply system. This makes it possible to use another type of ink for this inkjet recording apparatus.

When filling with other types of ink, FIG.
Needless to say, the sequence shown in FIG. In some cases, the ejection head unit 1 may be replaced with one suitable for the ink to be used. Further, the above-described cleaning operation may be performed a plurality of times in order to more reliably perform the cleaning in the ink path.

The ink exchange includes, for example, a combination of cyan, magenta, yellow, black, light cyan and light magenta to an ink using a special color such as a combination of cyan, magenta, yellow, black, orange, blue and green. Or the replacement of dye and pigment inks and the replacement of reactive inks and dispersible inks, etc., and according to the present invention, it is possible to cope with any of these uses.

As described above, the ink jet recording apparatus according to the present embodiment includes a main tank sub-tank tube 65 for feeding the ink in the sub-tank 3 into the main tank 2, and a main tank sub-tank tube 65.
And a main tank sub-tank valve 64 for closing the sub-tank. The bottom of each of the sub-tank 3 and the holding tank 33 is inclined. By arranging the tip of the holding tank tube 26 at the lowermost part in the holding tank 33, it is possible to drain the ink in the ink supply path, and to replace the ink in the ink jet recording apparatus.

Therefore, in a conventional liquid discharge recording apparatus such as an ink jet recording apparatus, due to the structure of the apparatus,
After one kind of ink has been filled in the flow path, it is impossible to flow another ink into the flow path. Can be used, and a plurality of types of ink can be selectively used depending on the user's application. Further, the present invention is not limited to the inkjet recording apparatus,
The present invention can be applied to another liquid ejection recording apparatus different from the ink jet recording apparatus.

(Second Embodiment) FIG. 2 is a flowchart for explaining an ink draining method of an ink jet recording apparatus as a liquid discharging method of a liquid discharge recording apparatus according to a second embodiment of the present invention. The ink draining method of the present embodiment and the ink draining method of the first embodiment
While the ink in the sub-tank is first sent to the holding tank in the ink draining method of the inkjet recording apparatus according to the embodiment, the ink in the holding tank is first collected in the sub-tank in the ink discharging method of the present embodiment. Are different. Therefore, the ink jet recording apparatus to which the ink draining method of the present embodiment is applied is exactly the same as that of the first embodiment, and the following description will focus on differences from the first embodiment.

First, when the ink path is filled with ink, the air release valve 63, the sub tank holding tank valve 39, the main tank sub tank valve 64, the buffer valve 46, and the main tank valve 66 are driven to (S165, S166, S167, S168, S168)
169). Next, by rotating the rotor of the supply pump 41 in the direction of the arrow U in FIG. 5 to drive the supply pump 41 to rotate forward for a certain period of time (S170, S171), the air in the pump tube 42 is displaced by the arrow in FIG. It is sent in the direction of R to make the inside of the sub tank 3 a negative pressure. As a result, the ink in the sub tank tube 21 is
The ink in the air buffer 49 is sucked into the sub tank tube 21 through the sub tank 3. At this time, the ink in the holding tank 33 is sucked into the air buffer 49 through the holding tank tube 26, and the operation of sucking the ink is performed until almost all the ink in the holding tank 33 is exhausted.

While the supply pump 41 is driven to rotate forward and the inside of the sub-tank 3 is maintained at a negative pressure, all the ink in the holding tank 33 is sucked into the sub-tank 3 through the holding tank tube 26. When almost all the ink in the holding tank 33 is exhausted, the atmosphere opening port 5 of the holding tank 33 is opened.
1 flows into the holding tank tube 26 from the end of the holding tank tube 26 through the end of the holding tank tube 26, and flows into the holding tank tube 26.
Through the air buffer 49.

Here, the end of the sub tank tube 21 on the side of the air buffer 49 is inserted into the air buffer 49 from above the air buffer 49, and the tip of the sub tank tube 21 is disposed at the top inside the air buffer 49. Therefore, when air from the holding tank 33 flows into the air buffer 49 through the holding tank tube 26, the ink in the air buffer 49 does not flow into the sub tank tube 21, and the ink in the air buffer 49 passes through the holding tank tube 26. The air flowing into the holding tank tube 26 flows into the holding tank tube 26. After that, all the ink in the sub tank tube 21 flows into the sub tank 3, and the holding tank tank tube 26 and the sub tank tube 21 are filled with air. Therefore, in this operation, the ink inside each of the holding tank 33, the holding tank tube 26, and the sub tank tube 21 is all collected in the sub tank 3 except for the ink remaining in the air buffer 49.

Next, after the supply pump 41 is driven to rotate forward, ink is sucked into the sub-tank 3 after a certain period of time, and the sub-tank valve 38 is closed from that state (S1).
72), the main tank sub-tank valve 64 is opened (S17).
3). Next, the rotor of the supply pump 41 is moved by the arrow T in FIG.
The sub-tank 3 is made to have a positive pressure by rotating the supply pump 41 in the reverse direction for a certain period of time (S174, S175). Thereby, the ink in the sub tank 3 is sent to the main tank 2 through the sub tank main tank tube 65.

After the supply pump 41 is driven in reverse, after a certain period of time all the ink in the sub-tank 3 and the main tank sub-tank tube 65 has been sent to the main tank 2, the supply pump 41 is driven in reverse. To open the sub tank valve 38 (S176) and close the main tank sub tank valve 64 (S177). As a result, the pressure in the sub tank 3 becomes positive, whereby the air in the sub tank 3 is sent into the air buffer 49 through the sub tank tube 21, and the ink in the air buffer 49 and the ink in the holding tank tube 26 are sent into the holding tank 33. It is. In the subsequent ink draining operation, (S148) to (S16) in the ink draining operation of the first embodiment.
By performing the step 4), the ink in the holding tank 33 is sent into the main tank 2 via the sub-tank 3, and the ink in the head supply tube 20 and the ink in the ejection head unit 1 are transferred via the cap 47. Then, the ink is sucked into the waste ink tank 52, and the ink draining operation of the ink path is completed. By such an ink draining operation, almost all of the ink in the ink path can be drained as in the ink draining operation in the first embodiment.

The cleaning operation after the completion of the above-described ink draining operation and the method of filling new ink are described in the first section.
Since the embodiment is completely the same as that of the first embodiment, the description thereof is omitted.

[0107]

As described above, according to the present invention, the inside of the sub-tank is closed and the pressure in the sub-tank is set to a positive pressure or a negative pressure by the pressure generating means. By collecting the liquid in the sub-tank and sending the collected liquid in the sub-tank through the fourth supply path into the main tank, almost all of the liquid in the liquid discharge recording apparatus can be drained. Can clean multiple tanks and supply paths, allowing a single liquid ejection recording device to use multiple types of inks and other liquids. As a result, multiple types of inks can be used depending on the user's application. Has the effect of becoming

[Brief description of the drawings]

FIG. 1 is a top view of an ink jet recording apparatus which is a liquid ejection recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a front view of the ink jet recording apparatus shown in FIG.

FIG. 3 is a sectional view taken along line Y-Y 'of FIG.

FIG. 4 is a sectional view of a main part of the inkjet recording apparatus shown in FIGS. 1 and 2;

FIG. 5 is a diagram showing an ink path of the ink jet recording apparatus shown in FIGS.

6 is a flowchart showing a sequence of an ink supply operation from a main tank to a sub tank in the ink path shown in FIG.

FIG. 7 is a flowchart illustrating a sequence of a forcible ink supply operation from the sub tank to the holding tank in the ink path illustrated in FIG. 5;

8 is a flowchart showing a sequence of an ink supply operation from the main tank to the sub tank and an ink supply operation from the sub tank to the holding tank in the ink path shown in FIG.

9 is a flowchart showing a sequence of an ink supply operation from the holding tank to the air buffer and an ink supply operation from the air buffer to the ejection head unit in the ink path shown in FIG.

FIG. 10 is a flowchart illustrating a sequence of an ink removal operation in the ink path illustrated in FIG. 5;

FIG. 11 is a flowchart showing a sequence of an operation subsequent to the suction operation by the cap shown in FIG. 10;

FIG. 12 is a flowchart illustrating a liquid draining method of the liquid ejection recording apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge head part 2 Main tank 3 Sub tank 4 Carriage stay 5 Manual feed roller 6 Pulley 7 Main scanning rail 8 Main scanning motor 9 Suction tube 15 Recording paper 16 Carriage 18 Belt 19 Sub scanning roller 20 Head supply tube 21 Sub tank tube 22, 23 Side plate 24 Housing 26 Holding tank tube 27 Main board 28 Flexible cable 29 Discharge roller 30 Feed roller 31 Caterpillar 32 Main tank tube 33 Holding tank 34 Sub tank holding tank tube 35 Straight printed matter 36 Manual driven roller 37 Straight driven roller 38 Sub tank valve 39 Sub tank holding tank valve 41 Supply pump 42 Pump tube 43 Electrode A 44 Electrode B 45 Electrode C 46 Buffer valve 47 Cap 48 Suction Pump 49 Air buffer 51 Atmospheric release port 52 Waste liquid tank 54 Joint 55 Rubber stopper 56 Needle 59 Nozzle surface 63 Atmospheric release valve 64 Main tank subtank valve 65 Main tank subtank tube 66 Main tank valve 67 Tube 71 Manual outlet 72 Insertion port 73 Insertion Mouth 74 Conveyance path

Continuation of the front page F term (reference) 2C056 EA04 EA12 EA22 EC15 EC65 FA03 JC05 JC08 JC13 KA04 KB04 KB08 KB10 KB11 KB16 KB21 KB37

Claims (15)

[Claims] An ejecting head for recording on the recording medium by ejecting a liquid toward the recording medium; a holding tank for retaining ink to be supplied to the ejecting head; A sub-tank holding an ink to be supplied to the holding tank and having an air introduction passage through which air can be introduced; a main tank holding a liquid to be supplied to the sub-tank; and a liquid in the holding tank to the ejection head unit. A first supply path for supplying the liquid, the one end being connected in the middle of the first supply path, and the other end being connected to the sub tank, for supplying the liquid in the sub tank to the ejection head unit; A second supply path, a supply path for supplying the liquid in the sub-tank to the holding tank, a pressure for making the inside of the sub-tank a positive pressure, and an inside of the sub-tank A pressure generating means for generating a pressure for generating a negative pressure, and a liquid in the main tank, the one end being connected to an upper part of the sub tank and the other end being arranged at a lower part in the main tank, for supplying the liquid in the main tank to the sub tank A third supply path for feeding the liquid in the sub-tank into the main tank, one end of which is connected to the upper part of the main tank and the other end of which is disposed in the lower part of the sub-tank. And a supply path. 2. The apparatus according to claim 1, further comprising: a carriage on which the discharge head is mounted and which reciprocates; and a housing to which the carriage is attached, wherein the holding tank, the sub tank, and the main tank are attached to the housing. 2. The liquid ejection recording apparatus according to claim 1, wherein: 3. The liquid discharge recording apparatus according to claim 1, wherein a flow path resistance of the first and second supply paths is smaller than a flow path resistance of the third supply path. 4. A pump according to claim 1, wherein said pressure generating means for generating a positive pressure or a negative pressure in said sub-tank is a pump for generating a positive pressure or a negative pressure in said sub-tank by forward or reverse drive. The liquid ejection recording apparatus according to claim 1. 5. The sub-tank according to claim 1, wherein a bottom surface in the sub-tank is inclined, and tips of the second and fourth supply paths are disposed at a lowermost portion in the sub-tank. Liquid ejection recording device. 6. The supply tank according to claim 1, wherein a bottom surface in the holding tank is inclined, and a tip of each of the first supply passage and the supply passage is arranged at a lowermost portion in the holding tank.
The liquid ejection recording apparatus according to any one of the above. 7. The liquid discharge recording apparatus according to claim 1, wherein an end of the fourth supply path is detachably attached to the main tank. 8. A waste liquid tank for holding an unnecessary liquid, the end of the fourth supply path on the main tank side being connectable in place of the main tank. The liquid ejection recording apparatus according to any one of the above. 9. The liquid discharge recording apparatus according to claim 1, wherein the discharge head section has an electrothermal transducer that generates heat energy used for discharging the liquid. 10. A liquid supply method for a liquid discharge recording apparatus for supplying liquid in the main tank to the discharge head unit in the liquid discharge recording apparatus according to claim 1, wherein the liquid supply method is provided in the sub tank. The atmosphere introduction passage, the second supply passage, and the fourth supply passage are closed, and the inside of the sub-tank is closed while the inside of the sub-tank communicates with the inside of the main tank via the third supply passage. A step of supplying a liquid in the main tank into the sub-tank through the third supply path by making the inside of the sub-tank a negative pressure by the pressure generating means; Measuring the amount, and opening the air introduction passage based on the measurement result of the liquid amount in the sub-tank to bring the inside of the sub-tank to atmospheric pressure. Liquid supply method of a liquid discharge recording apparatus. 11. A step of closing the air introduction passage after the step of opening the air introduction passage provided in the sub-tank to make the inside of the sub-tank an atmospheric pressure, and closing the second supply passage. A step of closing the fourth supply path; a step of closing the third supply path; and a step of supplying the liquid in the sub tank by making the inside of the sub tank positive pressure by the pressure generating means. A step of supplying the holding tank through a passage, a step of opening the air introduction passage to make the inside of the sub tank atmospheric pressure, a step of opening the second supply path, and an opening of the fourth supply path 11. The liquid supply method for a liquid ejection recording apparatus according to claim 10, further comprising: performing a step of opening the third supply path. 12. A step of closing the atmosphere introduction passage after the step of opening the atmosphere introduction passage provided in the sub-tank and setting the inside of the sub-tank to atmospheric pressure, and the step of closing the liquid in the sub-tank to the holding tank. Closing the supply passage for supplying to the first supply passage; closing a portion of the first supply passage from a connection portion with the second supply passage to the discharge head portion; A step of closing the supply path, a step of closing the third supply path, and a step in which the pressure in the sub-tank is reduced to a negative pressure by the pressure generating means, thereby causing the liquid in the holding tank to pass through the first supply path.
Feeding the portion between the connection portion with the second supply path and the holding tank, opening the air introduction passage to make the inside of the sub tank atmospheric pressure, and opening the supply passage A step of opening the fourth supply path; a step of opening the third supply path; and a portion of the first supply path connected to the second supply path to the ejection head section. And supplying a liquid from the first and second supply passages to the discharge head unit by applying a negative pressure to the inside of the discharge head unit, and from the outside of the discharge head unit. 12. The liquid supply method for a liquid discharge recording apparatus according to claim 10, further comprising a step of sucking liquid from the discharge head unit. 13. A liquid discharging method in a liquid discharge recording apparatus, wherein the liquid is discharged from a liquid supply path from the main tank to the discharge head in the liquid discharge recording apparatus according to claim 1. Closing the atmosphere introduction passage provided in the step; closing the supply passage for supplying the liquid in the sub tank to the holding tank; and supplying the second supply of the first supply passage. A step of closing a portion from a connection portion with a passage to the discharge head section; a step of closing the fourth supply path; a step of closing the third supply path; and the generation of the pressure in the sub tank. Means for causing the liquid in the sub-tank to pass through the second supply path and the first supply path from the connection portion of the second supply path to the holding tank by applying a positive pressure to the holding tank. Sending the liquid into the holding tank; opening the supply passage; closing the second supply passage; and causing the pressure in the sub-tank to be a negative pressure by the pressure generating means, thereby changing the liquid in the holding tank. Feeding the sub-tank through the supply passage, closing the supply passage, opening the fourth supply passage, and applying a positive pressure to the sub-tank by the pressure generating means. Sending the liquid inside the main tank through the fourth supply path into the main tank; closing the fourth supply path; opening the third supply path; and the first supply path Opening a portion from a connection portion with the second supply path to the ejection head portion, and sucking a liquid in the ejection head portion from outside the ejection head portion, Opening the air introduction passage to make the inside of the sub-tank an atmospheric pressure; opening the second supply passage; opening the supply passage; and opening the fourth supply passage A liquid discharging method in a liquid discharge recording apparatus having: 14. A liquid discharging method in a liquid discharge recording apparatus, wherein the liquid is discharged from a liquid supply path from the main tank to the discharge head unit in the liquid discharge recording apparatus according to claim 1. Closing the atmosphere introduction passage provided in the step; closing the supply passage for supplying the liquid in the sub tank to the holding tank; and supplying the second supply of the first supply passage. A step of closing a portion from a connection portion with a passage to the discharge head section; a step of closing the fourth supply path; a step of closing the third supply path; and the generation of the pressure in the sub tank. By applying a negative pressure by means, the liquid in the first supply path, inside the part from the holding tank to the connection part with the second supply path, and the liquid in the second supply path are filled in the sub-tank. Send to A step of closing the second supply path; a step of opening the fourth supply path; and a step of making the inside of the sub-tank a positive pressure by the pressure generating means, through the fourth supply path. Sending the liquid in the sub-tank into the main tank; opening the second supply path; closing the fourth supply path; opening the supply path; A step of closing the supply path, and a step of sending the liquid in the holding tank into the sub tank through the supply path by making the inside of the sub tank a negative pressure by the pressure generating means; and closing the supply path. Opening the fourth supply path; and causing the pressure in the sub-tank to be positive by the pressure generating means so that the liquid in the sub-tank passes through the fourth supply path. Feeding into the storage tank, closing the fourth supply path, opening the third supply path, and connecting the first supply path with the second supply path. A step of opening a portion up to the discharge head section; a step of sucking a liquid in the discharge head section from outside the discharge head section; and a step of opening the air introduction passage to make the inside of the sub tank atmospheric pressure. A liquid discharging method in a liquid ejection recording apparatus, comprising: a step of opening the second supply path; a step of opening the supply path; and a step of opening the fourth supply path. 15. The liquid discharge recording according to claim 13, wherein the liquid is supplied from the main tank in a liquid supply path from the main tank to the discharge head portion and in the discharge head portion. 13. The method according to claim 12, further comprising: removing a liquid from the liquid supply path and the discharge head unit by a liquid removal method in an apparatus; replacing the main tank with a cleaning tank containing a cleaning liquid; 15. The step of supplying the cleaning liquid by the liquid supply method of the liquid discharge recording apparatus according to the above, and the step of draining the cleaning liquid in the liquid supply path by the method of draining the liquid in the liquid discharge recording apparatus according to claim 13 or 14. And a step of replacing the cleaning tank with a main tank that holds another liquid different from the liquid. Liquid replacement method.