JPH09201982A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the meniscus of an ink nozzle from retreating and eliminate the clogging of the ink nozzle while effectively reducing the amt. of ink discharged to a waste ink tank at a time of restoring processing. SOLUTION: An ink eject recording apparatus has a recording head 2 provided with a large number of ink nozzles 1 and an ink supply passage 4 supplying the ink in an ink cartridge 3 to the recording head 2 and is constituted so as to emit ink to recording paper from the ink nozzles 1 to record an image. In this case, an opening and closing valve 9 bringing the ink supply passage to an open state when the ink ejecting recording apparatus is used and bringing the same to a closed state when the ink eject recording apparatus is not used is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a recording head provided with a plurality of ink nozzles and an ink chamber communicating with the ink nozzle, and an ink supply passage for supplying the ink in the ink cartridge to the recording head. In addition, the present invention relates to an inkjet recording apparatus that records an image by ejecting ink from the recording head onto recording paper.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 5-185661, an ink jet recording apparatus having a recording head for ejecting ink by utilizing thermal energy generated by an electrothermal converter is used. The capping unit that covers the nozzle forming surface of
By capping the recording head in an inoperative state with the capping unit, it is possible to prevent the ink in the ink nozzles from drying.

Further, after the recording by the ink jet recording apparatus is completed or before the recording is started, a recovery means for sucking the ink in the ink nozzle is provided while the recording head is capped by the capping unit, and the ink nozzle is clogged by the recovery means. There is known an ink jet recording apparatus configured to remove foreign matter such as dust.

[0004]

In the ink jet recording apparatus having the above-mentioned structure, the nozzle forming surface of the recording head is covered with the capping unit to dry the ink in the ink nozzle and to intrude foreign matters and the like into the ink nozzle. However, when pressure fluctuation occurs in the ink chamber due to movement of the ink in the ink chamber provided in the recording head to the ink cartridge side when the image is not recorded, There is a problem that the meniscus of the ink nozzle cannot be prevented from receding.

Particularly, in an ink jet recording apparatus having a large number of ink nozzles of a line type or the like, the number of ink nozzles provided in a recording head is larger than that of an ink jet recording apparatus having a small number of ink nozzles used in a serial type or the like. However, since the capacity of the ink chamber communicating with this is also large, it is difficult to maintain a constant pressure inside the ink chamber, and the meniscus receding phenomenon easily occurs due to pressure fluctuation inside the ink chamber. There is.

Further, in an ink jet recording apparatus which needs to be provided with a large number of ink nozzles of the line type or the like, the ink in the ink nozzles is sucked by the recovery means before or after the recording is completed, and the ink of the ink nozzles is drawn. Since a large amount of ink is simultaneously sucked from a large number of ink nozzles during the recovery process for clearing the clogging, there is a drawback that an increase in the amount of ink discharged from the waste ink tank cannot be avoided.

In view of such circumstances, the present invention provides an ink jet recording apparatus capable of effectively preventing the meniscus of the ink nozzle from receding. The present invention also provides an inkjet recording apparatus capable of reliably eliminating clogging of ink nozzles while effectively reducing the amount of ink discharged to a waste ink tank during recovery processing.

[0008]

The invention according to claim 1 is
A recording head having a large number of ink nozzles and an ink supply passage for supplying the ink in the ink cartridge to the recording head are provided, and an image is recorded by ejecting ink from the ink nozzles onto recording paper. In the ink jet recording apparatus configured as described above, an opening / closing valve is provided which opens the ink supply passage when the ink jet recording apparatus is used and closes the ink supply passage when the ink jet recording apparatus is not used.

According to the above construction, when the ink jet recording apparatus is used, the ink supply passage is opened by the opening / closing valve, so that the ink in the ink cartridge is transferred through the ink supply passage to the ink chamber of the recording head. And the image is recorded. Further, when the ink jet recording apparatus is not used, the ink supply passage is closed by the opening / closing valve to prevent the ink in the ink chamber from moving to the ink cartridge side through the ink supply passage. become.

According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect, a plurality of independent ink chambers independent of each other are provided in the recording head, and a plurality of ink passages respectively communicating with the respective independent ink chambers are provided. An on-off valve that is provided in the ink supply passage and that opens and closes each ink passage is provided in each ink passage.

According to the above construction, when the ink jet recording apparatus is used, each of the ink supply passages is opened by the opening / closing valve, so that the ink in the ink cartridge is transferred to the recording head through the ink supply passage. Images are recorded by being supplied to each independent ink chamber,
When the ink jet recording apparatus is not used, each of the ink passages is closed by the opening / closing valve, so that the ink in each independent ink chamber is prevented from moving to the ink cartridge side through the ink passage. Become. Also, during the recovery process to clear the clogging of the ink nozzles, the specific on-off valve is opened and the other on-off valves are closed, so that the ink in the ink nozzles communicating with the specific independent ink chamber is concentrated. Will be sucked in and the clogging will be eliminated.

According to a third aspect of the present invention, in the ink jet recording apparatus according to the second aspect, the ink chamber specifying means for specifying an independent ink chamber communicating with the ink nozzle in which the clogging has occurred and the ink in the ink nozzle are provided. The recovery means for sucking and eliminating the clogging of the ink nozzle and the opening / closing valve of the ink passage connected to the independent ink chamber specified by the ink chamber specifying means are opened and connected to another independent ink chamber. Control means for activating the recovery means in a state where the on-off valve of the ink passage is closed is provided.

According to the above construction, in response to the output signal of the ink chamber specifying means, the ink in the ink nozzle is recovered by the recovering means with only the opening / closing valve of the ink passage connected to the specific independent ink chamber being opened. By being sucked, the ink in the specific independent ink chamber is intensively sucked, and the above clogging is effectively eliminated.

[0014]

1 shows an embodiment of an ink jet recording apparatus according to the present invention. In this ink jet recording apparatus, a recording head 2 provided with a large number of ink nozzles 1 for ejecting ink, an ink cartridge 3 containing recording ink, and the ink in the ink cartridge 3 is transferred to the recording head 2. An ink supply passage 4 for supplying the ink and a recovery means 5 for sucking the ink in the ink nozzle 1 are provided.

The recording head 2 is formed with a plurality of independent ink chambers 6a to 6c which are independent of each other, and each of the independent ink chambers 6a to 6c has a common ink chamber 7 of the ink supply passage 4.
Also, an ink passage 9 communicating with the ink cartridge 3 via the ink outlet 8 is connected thereto. Further, the common ink chamber 7 is provided with a plurality of opening / closing valves 10 for individually opening / closing the upper end openings of the ink passages 9.

The on-off valve 10 includes a valve body 11 made of a magnetic material, which is disposed above each ink passage 9 in the common ink chamber 7, and above the common ink chamber 7 at a position facing the valve body 11. And an electromagnet 12 installed in the. The valve body 11 is normally held at a lowered position where it abuts the upper end opening portion of the ink passage 9 by its own weight or a restoring force to close the ink passage 9, and in response to a control signal output from the control means 13 described later. When the electromagnet 11 is turned on by the magnetic force, it is attracted upward by the magnetic force and is driven to a position where the ink passage 9 is opened.

The recovery means 5 is a capping unit 14 for covering the nozzle forming surface provided on the lower surface of the recording head 2 to make it hermetically sealed, and the capping unit 1.
4 has a discharge passage 15 connected thereto, a vacuum pump 16 provided in the discharge passage 15, and a waste ink tank 17, and the suction force of the vacuum pump 16 causes the inside of the capping unit 14 to be in a negative pressure state. By doing so, the ink in the ink nozzle 1 is sucked and discharged to the waste ink tank 17.

In addition, in the ink jet recording apparatus, an independent ink chamber 6 communicating with the clogged ink nozzle 1 is formed.
Recovery processing for driving the ink chamber specifying unit 18 including an operation switch that outputs a command signal for specifying a to 6c, the opening / closing valve 10 and the vacuum pump 16 to eliminate clogging of the ink nozzle 1. And an input unit 19 including an input switch for inputting the execution signal of.

The control means 13 outputs a control signal for opening all the on-off valves 10 provided in the common ink chamber 7 when the ink jet recording apparatus in which the ink jet recording apparatus is powered on is used, and The on-off valve 11 of each ink passage 9 connected to the independent ink chambers 6a to 6c communicating with the clogged ink nozzle 1 is opened in response to a command signal output from the ink chamber specifying unit 18 when an image is not recorded. It is configured to output a control signal for setting the state. Further, the control means 13 outputs a control signal for moving the recording head 2 to the installation position of the capping unit 14 to a drive means (not shown) in accordance with the recovery processing execution signal input from the input means 22, and then outputs the control signal. It is configured to output a control signal for operating the vacuum pump 16.

The ink jet recording apparatus having the above-mentioned structure records an image by ejecting the ink on the recording paper by heating the ink in the ink nozzle 1 by the electrothermal converter provided in the recording head 2. In response to the ejection of the ink, the ink in the ink cartridge 3 is led out into the common ink chamber 7 through the ink lead-out passage 8, and from the common ink chamber 7 through the ink passage 9 the respective independent ink chambers 6 are formed.
The above ink is replenished to a to 6c.

When the user determines whether or not the ink nozzle 1 is clogged according to the image forming state at the start of image recording or the like, and the occurrence of the clogging is confirmed. A command signal corresponding to the location of the clogging is input from the ink chamber specifying means 18.

For example, when the ink chamber specifying means 18 specifies the independent ink chamber 6a located on the left side of FIG. 1, a control signal corresponding to this is output from the control means 13 to each on-off valve 10. As a result, the electromagnet 12 of the on-off valve 10 located on the left side is turned on to open the ink passage 9 connected to the independent ink chamber 6a, and the electromagnet 1 of the on-off valve 10 located on the central portion and the right side is opened.
2 are turned off, and the independent ink chambers 6b and 6b
The ink passage 9 connected to c is closed.

When an execution signal for instructing the execution of the recovery process is input by the input means 19, the vacuum pump 16 is driven to bring the inside of the capping unit 14 into a negative pressure state, and the independent ink chamber 6a. The ink in each of the communicating ink nozzles 1 is sucked into the capping unit 14 and discharged to the waste tank 17, so that the foreign matter or the like causing the clogging is removed and the clogging is eliminated.

That is, when the inside of the capping unit 14 becomes a negative pressure state according to the suction force of the vacuum pump 16, the ink in the common ink chamber 7 and the ink cartridge 3 is left on the left side with the opening / closing valve 10 in the open state. Since the ink is introduced into the independent ink chamber 6a through the ink passage 9 at a predetermined volume velocity, foreign matter or the like clogging the ink nozzle 1 is pushed out by the ink into the capping unit 14 and the ink nozzle 1 is exposed. The clogging will be cleared.

When the recording operation of the ink jet recording apparatus is completed and the power is turned off, the on-off valve 10
The electromagnet 12 is turned off and the valve body 11 closes each ink passage 9 to cut off the electrical connection between the common ink chamber 7 and each of the independent ink chambers 6a to 6c.

In the ink jet recording apparatus having the recording head 2 provided with a large number of ink nozzles 1 as described above and the ink supply passage 4 for supplying the ink in the ink cartridge 3 to the recording head 2, Since the ink supply passage 4 is closed by the on-off valve 10 when not in use, the ink in each of the independent ink chambers 6a to 6c provided in the recording head 2 passes through the ink supply passage 4 and the ink cartridge. It is possible to prevent the movement to the 3 side. Therefore, when the ink jet recording apparatus is not used, it is possible to reliably prevent the pressure fluctuation due to the movement of the ink in the independent ink chambers 6a to 6c.
It is possible to effectively prevent the meniscus of FIG.

In the above embodiment, the recording head 2 is provided with a plurality of independent ink chambers 6a to 6c, and a plurality of ink passages 9 communicating with the independent ink chambers 6a to 6c are individually opened and closed by the on-off valves 10. Since it is configured to open and close in the same manner, even in a line type inkjet recording apparatus having a large number of ink nozzles 1, when the inkjet recording apparatus is not used, the meniscus recedes due to the movement of the ink in each ink nozzle 1. Can be effectively prevented.

That is, when a single ink chamber with a large amount of welding is formed in the recording head 2, the internal pressure of the ink chamber is likely to drop due to the ink being washed away or vaporized. Since it is difficult to keep the ink pressure constant, it is inevitable that the meniscus recedes frequently due to the fluctuation of the internal pressure of the ink chamber. On the other hand, when the ink chamber is divided into a plurality of independent ink chambers 6a to 6c which are independent of each other as described above, the volume of the ink chamber is smaller than that when a single ink chamber is provided in the recording head. Since it can be made small, by closing each of the on-off valves 10 and closing the independent ink chambers 6a to 6c, the internal pressure of the independent ink chambers is kept constant and the retreat of the meniscus is effectively prevented. You can

In addition, at the time of recovery processing for eliminating the clogging of the ink nozzle 1, the recovery means 5 is operated with the specific opening / closing valve 10 opened and the other opening / closing valve 10 closed to operate the ink of the ink nozzle 1. Open and close valve 1
Ink is introduced into any of the independent ink chambers 6a to 6c at a predetermined volume velocity through a specific ink passage 9 in which 0 is open, and foreign substances clogging the ink nozzle 1 along with the ink are capped by the capping unit 14. It can be pushed in.

Therefore, as compared with the conventional apparatus configured to eject ink simultaneously from all the ink nozzles provided in the recording head, the recording head 2 is discarded through the capping unit 14 and the discharge passage 15 during the recovery process. The amount of ink discharged to the tank 17 and discarded can be suppressed, and clogging of the ink nozzle 1 can be reliably eliminated.

For example, as shown in the above embodiment, when the ink chamber of the recording head 2 is divided into three independent ink chambers 6a to 6c, the volume velocity of the ink sucked from each ink nozzle 1 is Since it can be set to three times that in the case where a single ink chamber is provided in the recording head, a high pressure can be applied to the ink nozzle 1 to reliably eliminate the clogging of the ink nozzle 1. Even when the flow rate of the ink sucked by the vacuum pump 16 is set to 1/3 of that of the conventional device, the volume velocity of the ink ejected from each ink nozzle 1 can be set to the same value as that of the conventional device. Therefore, the amount of ink discharged to the waste tank 17 can be significantly reduced as compared with the conventional device.

Further, in the above embodiment, the ink chamber specifying means 18 including the operation switch for specifying the independent ink chambers 6a to 6c communicating with the clogged ink nozzle 1 is formed.
And a control means 13 for controlling the opening / closing of the on-off valve 10 according to the output signal of the ink chamber specifying means 18, and among the independent ink chambers 6a-6c according to the control signal output from the control means 13. The opening / closing valve 10 of the ink passage 9 connected to the independent ink chamber specified by the ink chamber specifying means 18 is automatically opened, and the opening / closing valve 10 of the ink passage connected to another independent ink chamber is automatically opened. By operating the recovery means 5 in the closed state, it is possible to prevent the ink in the independent ink chamber, which does not need to perform the recovery process, from being sucked, and thus the waste ink tank 1
The clogging of the ink nozzles 1 can be quickly and reliably eliminated while effectively reducing the amount of ink discarded in 7.

It should be noted that instead of the ink chamber specifying means 18 consisting of the above-mentioned operation switches, the independent ink chambers 6a communicating with the clogged ink nozzle 1 in response to an output signal of a detection switch or the like for detecting the ink ejection state. The structure may be such that an ink specifying means for automatically specifying 6c is provided. Further, the ink chamber specifying means 18 is omitted, and the opening / closing valves 10 of the ink passages 9 connected to the independent ink chambers 6a to 6c are controlled to open / close at the time of power-on or periodically, respectively. The ink in 6a to 6c may be sequentially sucked.

Further, in the above embodiment, the valve body 11 made of a magnetic material for closing the ink passage 9 connected to each of the independent ink chambers 6a to 6c, and the electromagnet 1 for attracting the valve body 11.
2 is provided in the common ink chamber 7, and when the electromagnet 12 is turned off, the valve body 11 closes the ink passage 9 according to its own weight or the like. In addition, there is an advantage that the meniscus of each ink nozzle 1 can be maintained in a stable state when each ink passage 9 is automatically closed.

Instead of the above structure, as shown in FIGS. 2 and 3, the upper wall portion 20 of the common ink chamber 7 is made of a flexible material such as a plastic material and the upper end of the ink passage 9 is formed. A pressing member 22 that has a cylindrical protrusion 21 formed on its portion and presses the upper wall portion 20 of the common ink chamber 7 downward, and a drive unit that includes a solenoid 23 or a cam mechanism 24 that drives this pressing member 22. The structure may be such that an on-off valve having is provided.

According to the on-off valve having the above structure, the control means 13
When the pressing member 22 is driven downward by the drive unit in accordance with the control signal output from the ink, the upper wall portion 20 of the common ink chamber 7 is pressed downward and press-contacts with the protrusion 21. The passage 9 is closed. When the pressing state of the pressing member 22 by the driving unit is released, the upper wall 20 is separated from the upper end opening of the ink passage 9 by its restoring force, so that the ink passage 9 is automatically opened. Return.

Further, as shown in FIG. 4, the common ink chamber 7
The opening 25 is sealed with a rod-shaped valve body 26 supported up and down in an opening 25 formed in the upper wall portion 20, a drive unit 27 including a solenoid for driving the valve body 26 up and down, and the like. An on-off valve having a seal member 28 such as an O-ring is provided, and the valve body 26 is lowered by the drive unit 27 so that its tip end is fitted into the upper end opening of the ink passage 9 as shown by the phantom line. Alternatively, the ink passage 9 may be closed. The pressing member 22
Alternatively, the valve body 26 may be configured to be driven up and down by a manual operation.

In each of the above-described embodiments, the example in which the opening / closing valve 10 for opening / closing the upper end opening of the ink passage 9 is provided in the common ink chamber 7 has been described, but the opening / closing valve for opening / closing the lower end opening of the ink passage 9 is described. The structure may be provided on the recording head 2. Further, as shown in FIG. 5, an opening / closing valve 10a composed of a globe valve (bulb valve) or a butterfly valve (butterfly valve) is provided in a conduit of the ink passage 9 connected to each independent ink chamber of the recording head 2. The opening / closing valve 10a may be provided to be opened / closed in response to a control signal from the control means, or may be opened / closed by manual operation.

Further, the ink chamber formed in the recording head 2 does not necessarily have to be divided into a plurality of independent ink chambers 6a to 3c, and the recording head 2 is provided with a single ink chamber and the ink chamber and the ink cartridge. A single on-off valve is provided in the ink supply passage that connects with, so that the on-off valve is opened when the power of the ink jet recording apparatus is turned on, and the on-off valve is closed when the power is turned off. You may comprise.

[0040]

As described above, according to the first aspect of the invention, when the ink jet recording apparatus is used, the ink supply passage connecting the recording head and the ink cartridge is opened, and when the ink jet recording apparatus is not used. Since the on-off valve that closes the ink supply passage is provided, it is possible to reliably prevent the pressure fluctuation due to the ink in the ink chamber in the recording head moving to the cartridge side when not in use. Therefore, there is an advantage that the meniscus of the ink nozzles provided in the recording head can be effectively prevented from receding with a simple configuration.

According to the second aspect of the invention, a plurality of independent ink chambers independent of each other are provided in the recording head, and on-off valves for individually opening and closing a plurality of ink passages respectively communicating with the respective independent ink chambers are provided. Since it is arranged, the volume of the ink chamber can be reduced as compared with the case where a single ink chamber is provided in the recording head, and
Each of the on-off valves described above can ensure that the independent ink chamber is hermetically sealed, thereby maintaining the internal pressure of each independent ink chamber constant and further effectively preventing the meniscus of the ink nozzle from retracting. be able to.

In addition, at the time of the recovery process for eliminating the clogging of the ink nozzles, the opening / closing valve is opened by opening the specific opening / closing valve and closing the other opening / closing valve to suck the ink from the ink nozzle by the recovery means. The ink is introduced into one of the independent ink chambers at a predetermined volume velocity through a specific ink passage that is in an open state, and the foreign matter that has clogged the ink nozzle along with the ink is pushed out into the capping unit and the ink nozzle There is an advantage that clogging can be effectively eliminated.

Further, in the invention according to claim 3, the ink chamber specifying means for specifying the independent ink chamber communicating with the clogged ink nozzle and the clogging of the ink nozzle by sucking the ink in the ink nozzle. A state in which the recovery means for eliminating and the opening / closing valve of the ink passage connected to the independent ink chamber specified by the ink chamber specifying means are opened and the opening / closing valve of the ink passage connected to another independent ink chamber is closed. Since the control means for operating the recovery means is provided, the recovery processing operation for eliminating the clogging of the ink nozzles can be automated and the work can be simplified, and the recovery processing can be performed independently. It is possible to prevent the ink in the ink chamber from being sucked and effectively reduce the amount of ink discharged to the waste ink tank.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of an inkjet recording apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of an on-off valve which constitutes an ink supply passage.

FIG. 3 is a cross-sectional view showing still another embodiment of the opening / closing valve.

FIG. 4 is a cross-sectional view showing still another embodiment of the opening / closing valve.

FIG. 5 is an explanatory view showing still another embodiment of the opening / closing valve.

[Explanation of symbols]

 1 Ink Nozzle 2 Recording Head 3 Ink Cartridge 4 Ink Supply Passage 6a, 6b, 6c Independent Ink Chamber 9 Ink Passage 10 Open / Close Valve 13 Control Means 18 Ink Chamber Identification Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Watanabe 1-2-2 Tamazo, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Takatoshi Nishimura 1-2-2 Tamazo, Chuo-ku, Osaka Mita Within Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A recording head having a large number of ink nozzles, and an ink supply passage for supplying the ink in the ink cartridge to the recording head, wherein the ink is ejected from the ink nozzles onto the recording paper. In an inkjet recording apparatus configured to record an image, an opening / closing valve is provided which opens the ink supply passage when the inkjet recording apparatus is used and closes the ink supply passage when the inkjet recording apparatus is not used. An ink jet recording apparatus characterized by the above. 2. A plurality of independent ink chambers independent of each other are provided in a recording head, a plurality of ink passages communicating with each independent ink chamber are provided in an ink supply passage, and an on-off valve for opening and closing each ink passage is provided. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is provided in each ink passage. 3. An ink chamber specifying unit that specifies an independent ink chamber that communicates with an ink nozzle having a clogging, a recovery unit that sucks ink in the ink nozzle to eliminate the clogging of the ink nozzle, and the ink. The recovery means is operated with the opening / closing valve of the ink passage connected to the independent ink chamber specified by the chamber specifying means being opened and the opening / closing valve of the ink passage connected to another independent ink chamber being closed. The inkjet recording apparatus according to claim 2, further comprising a control unit.