JP2005007720A - Ink supply/recovery mechanism and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of the cleaning (recovery) operation of an ink jet recording head that a method for cleaning the nozzle by pressurizing an ink bag with a recovery roller 1105 to force ink to be discharged through the ink ejection nozzle with correct pressure produces much waste ink, but a sub-tank required for reducing the amount of the waste ink by reversing the direction of the recovery roller after a certain period of time under a certain pressure has problems of difficulties in making itself compact as an ink supply system, of being impractical in speedy operation and necessary for a manometer due to the difficulty of a quantitative administration of the correct pressure. <P>SOLUTION: The ink supply/recovery mechanism is constituted in such a manner that a pressuring pump and a return side vale are used to open the return side valve closed for pressurization immediate after the finish of the recovery, or to change the pressure pump to a suction mode in a moment, rapidly reducing the residual correct pressure inside the recording head. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink supply / recovery mechanism for a recording head in an ink jet printer, and a recording apparatus including the same.
[0002]
[Prior art]
A conventional example relating to an ink supply and recovery system of an ink jet printer is shown in FIG.
[0003]
Ink to be recorded by a large number of quiescent nozzles 1108 of the recording head 1106 is supplied to the liquid chamber 1107 of the recording head 1106 via the ink cartridge 1101 to the valve 1113 to the sub tank 1102 to the valve 1114.
[0004]
During standby, the recording head 1106 is hermetically sealed by the capping mechanism 1109.
[0005]
If the recording operation is continued, bubbles may grow in the vicinity of the ink discharge nozzle 1108, and there is a concern that the subsequent normal recording operation may be hindered, or due to ink sticking in the vicinity of the ink discharge nozzle 1108 due to a long-term leaving or capping state. Since sound recording may not be possible, the recording head 1106 requires a cleaning (recovery) operation for recovering the ink discharge nozzle 1108 to a sound state.
[0006]
In the cleaning (recovery) operation, for example, when the ink bag 1103 in the sub tank is crushed by the recovery roller 1105 and pressurized, the ink is forcibly discharged from the ink discharge nozzle 1108 by the positive pressure, and the nozzle returns to a healthy state.
[0007]
The ink discharged at this time is caught by the capping mechanism 1109 and collected by the pump 1110 to the waste ink collecting unit 1111. Since the collected waste ink is not used for recording, it is wasted.
[0008]
Since the waste ink increases when the recovery roller 1105 is crushed, a pressure sensor 1112 is provided in the conventional example, and when the pressure continues for a certain period of time, the recovery roller 1105 is returned in the reverse direction to reduce the amount of waste ink. Some have been adopted.
(For example, Patent Document 1)
[Patent Document 1]
JP2000-141687 (pages 11 to 12, FIGS. 13, 14, and 15)
[0009]
[Problems to be solved by the invention]
In the case of the conventional method as described above, a sub-tank is required in addition to the replaceable ink cartridge, so that there is some difficulty in downsizing the ink supply system, and the positive pressure quantitative management that cannot be performed quickly is possible. However, there are problems such as requiring a pressure gauge because it is difficult.
[0010]
[Means and Actions for Solving the Problems]
The present invention has been made in view of the above, and in order to solve the above problems, the present invention implemented the following means.
[0011]
That is,
Using a compact mechanism with a pump and a valve, the positive pressure is quickly restored by simple control,
The amount of waste ink was reduced without impairing the recovery operation performance to restore the ink nozzles of the recording head to a healthy state.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 5 shows an ink supply channel of the ink jet printer embodying the present invention.
[0013]
This figure shows one station (one color), and when a plurality of recording heads are provided, the same ink flow path is provided in parallel corresponding to each recording head.
[0014]
According to the ink supply device of the present invention, the ink is stored in the casing member, which is an inelastic body, in the ink tank 503 and normally has a blocking structure against the outside. When the ink tank 503 is installed in the apparatus, an ink flow path is formed between the inside of the ink tank 503 and the tubes 530 and 531 by a configuration not shown, and the atmosphere provided in the ink tank 503 is opened to the atmosphere. The valve 504 is opened, and an air-flow path is formed between the inside and outside of the ink tank 503.
[0015]
A pump used for an operation related to cleaning (recovery) of the recording head 501 includes a pressurizing pump 505 and a suction pump 507 for sucking waste ink.
[0016]
Both pumps maintain ink circulation when not driven.
[0017]
FIG. 6 is a cross-sectional view showing the configuration of a reciprocating pressurization pump 505 employed in the present invention.
[0018]
The cam 603 has a central axis eccentric with respect to a perfect circle, and the lower portion of the piston 601 has a U-shape so as to sandwich the cam 603. Thereby, it can convert into a reliable vertical motion, without the sliding surface with piston 601 leaving | separating with respect to rotation of the cam 603. FIG.
[0019]
In addition, an elastic body 602 that combines the cylinder 604 and the outside is combined with the upper end surface of the piston 601.
[0020]
When the cam 603 is rotated, the piston 601 moves up and down, and when the piston 601 is lowered in the downward V direction, the volume in the cylinder 604 increases, and ink is sucked into the cylinder 604 from the suction one-way valve 605, and then When the piston 601 moves up in the W direction, the volume decreases and ink is discharged from the discharge one-way valve 606.
[0021]
There are two modes for the cleaning (recovery) operation of the recording head 501 using the pressurizing pump 505, which are controlled according to the respective purposes.
[0022]
Ink pressurization cleaning; the ink discharge nozzle 511 and bubbles or foreign matter in the vicinity thereof, or ink fixed by the discharge nozzle 511 are forcibly discharged.
[0023]
Returning to FIG. 5 again, the pressure valve 520 is closed, and the pressure pump 505 is driven to pressure-feed ink to the ink tank 503 to the pressure pump 505 to the recording head 501.
[0024]
Then, the pressure-fed ink flows into the liquid chamber 512 inside the recording head 501 and is forcibly discharged from the ink discharge nozzle 511.
[0025]
As a result, each nozzle 511 of the recording head 501 is recovered to a healthy state.
[0026]
In the case of the recording head 501 according to the present invention, the positive pressure applied to the ink discharge nozzle 511 in the cleaning is 30 [Kpa] or more.
[0027]
Ink circulation cleaning; an object is to remove bubbles remaining in the ink flow path between the ink tank 503 and the recording head 501.
[0028]
Specifically, by operating the pressurizing pump 505 with the pressurizing valve 520 opened, ink is supplied from the ink tank 503 to the tube 530 to the pressurizing pump 505 to the tube 514 to the tube 515 to the pressurizing valve. After passing through the tube 520 to the tube 531, it is circulated again to the ink tank 503. In this operation, little ink is pushed into the liquid chamber 512 of the recording head 501 by the flow resistance of the ink filter 513.
[0029]
Incidentally, the ink forcibly discharged from the ink discharge nozzle 511 by the cleaning operation is caught in the cap of the capping mechanism 502 as waste liquid, and the tube 516 to the waste ink pump are sucked by the suction force of the waste ink pump 507. 507 to tube 517 to waste ink tank 508 are stored.
[0030]
The waste ink tank 508 is provided with an air opening 510 so that the waste ink pump 507 can smoothly transport the waste ink.
[0031]
Further, during the recording operation, the pressurizing valve 520 is opened, and ink is automatically supplied to the print head 501 from both the tubes 530 and 531 mainly by the action of capillary action by the ink discharge nozzle 511.
[0032]
In this embodiment, at the time of ink pressurization cleaning, the pressurization valve 520 is opened when the positive pressure applied to the ink discharge nozzle 511 falls below the pressure at which a sufficient cleaning effect is obtained, and the positive pressure is set to the ink tank. The residual pressure is rapidly reduced by letting it escape to 513.
[0033]
FIG. 1 shows the positive pressure applied to the ink discharge nozzle 511 with respect to the time axis during the cleaning in this embodiment. A to C and T represent the operation process of the pressurizing pump 505 or the pressurizing valve 520, respectively, A: pressurizing operation → piston ascent process B: standby operation → piston stop process (the stop process here is the piston top dead) In point)
C: Inhalation operation → Piston descending process (Return piston position to bottom dead center and prepare for next operation)
T :: Pressurization valve opening timing.
[0034]
In the pressurizing operation A, the internal pressure in the vicinity of the ink discharge nozzle 511 suddenly rises, and in this embodiment, the ink is forcibly and suddenly pushed out from the ink discharge nozzle 511 in a section: m where the internal pressure exceeds 30 [Kpa]. All nozzles are restored to a healthy state.
During the standby operation B, the residual pressure tends to decrease gradually, but when the pressurizing valve 520 is opened at a timing near T: T of 30 Kpa, the residual pressure rapidly decreases as indicated by the waveform 101. -The amount of waste liquid (waste ink) can be reduced without impairing the effect of ning.
[0035]
In this embodiment (embodiment 1), the pressurization valve opening timing is performed according to a sequence set in advance in the apparatus. However, in the present invention, such means is not limited. For example, a pressure sensor is provided in the flow path. May be performed by feeding back the detection value from the sensor.
[0036]
In FIG. 1, when the amount of waste ink consumed during the pressure cleaning is compared between the internal pressure waveform 101 according to the present embodiment and the waveform 102 of the conventional method, the hatched portion can be approximately reduced by the present invention. Point to the amount.
[0037]
The amount of waste liquid is compared with the positive pressure applied to the ink discharge nozzle 511, and the amount of waste liquid between B and C is greatly reduced.
[0038]
Note that the timing X for opening the pressurizing valve 520 during the cleaning is not necessarily the timing described in the present embodiment. If the expected value of the recovery effect by the cleaning is satisfied, the opening timing T is set earlier. By shifting, the amount of waste ink is further reduced.
[0039]
Further, when the opening timing T is shifted backward, the amount of waste ink gradually increases, but it is clear that a waste ink reduction effect can be expected as compared with the waveform 102 of the conventional method.
[0040]
[Example 2]
In this embodiment, a pressurizing pump is also used, but the discharge side valve 606 (see FIG. 6) of the pressurizing pump 505 is unnecessary.
[0041]
In other words, the piston 601 is pushed upward once to perform a pressure recovery operation, and thereafter, when the pressure falls below a pressure at which a sufficient cleaning (recovery) effect is obtained, the piston 601 of the pressure pump 505 is pressed down to enter the suction process. The residual pressure in the cylinder 604 is eliminated, and as a result, the residual pressure applied to the ink discharge nozzle 511 is quickly reduced.
[0042]
During this time, the pressurization valve 520 is closed, but the pressurization valve 520 may be opened after the piston 601 starts to be pushed down.
[0043]
FIG. 2 shows the positive pressure applied to the ink discharge nozzle 511 with respect to the time axis during the cleaning in this embodiment. A1 to D1 and T1 represent the operation process of the pressurizing pump 505, respectively: A1: pressurization operation → piston ascent process B1: standby operation → piston stop process (the stop process here is the piston at the top dead center)
C1: Inhalation operation → Piston descending process D1: Initialization of piston position (If the piston is not lowered to the bottom dead center in C1, it returns to the bottom dead center and prepares for the next operation)
It is.
[0044]
In the pressurizing operation A1, the internal pressure in the vicinity of the ink discharge nozzle 511 suddenly rises, and in this embodiment, ink is forcedly and rapidly pushed out from the ink discharge nozzle 511 in a section: m where the internal pressure exceeds 30 [Kpa]. Each nozzle returns to a healthy state.
During the standby operation B1, the residual pressure tends to decrease gently, but when the suction operation is performed by appropriately lowering the piston 524 of the pressurizing pump 505 at the timing near T30 below T1, the residual pressure is as shown in the waveform 201. Since it rapidly decreases, the amount of waste liquid (waste ink) can be reduced without impairing the cleaning effect.
[0045]
Also in this embodiment, as already described in the first embodiment, the timing of the suction operation B1 does not necessarily have to follow the present embodiment.
[0046]
[Example 3]
In this embodiment, a pump capable of bi-directional ink feeding is used as the pressure pump 520.
[0047]
For example, a tube pump or the like is used as the pump.
[0048]
FIG. 3 shows a typical configuration of a tube system. A roller 302 is rotatably attached to the outer periphery of the rotating body 301 via a roller support member 307 and constantly pressed in the outer peripheral direction by a compression spring 308. However, the tip of the roller support member 307 comes into contact with the stopper portion of the rotating body 301 for a certain amount or more to prevent it from coming off.
[0049]
Three such rollers 302, roller support members 307, and compression springs 308 are arranged at equal intervals along the outer periphery of the rotating body 301. A tube support member 304 is attached to the outer periphery of the tube 303 so as to move up and down in association with the rotation of the cam 305 by a spring 306.
[0050]
The roller 302 on the tube 303 is in a state in which the roller support member 307 described above is retracted in the depth direction of the rotating body 301 from the state in which the roller supporting member 307 is in contact with the stopper portion of the rotating body 301.
[0051]
Therefore, if the roller 302 presses the tube 303 with a constant pressure by the compression spring 308 and the rotating body 301 is rotated by a driving device (not shown), ink can be sent along the rotation direction.
[0052]
When the ink is not sent, the tube support member 304 is retracted downward together with the tube 303 by rotating the cam 305 as shown in FIG. 3B, and the pressure applied by the roller 302 to the tube is also released. Therefore, the ink can be distributed.
[0053]
Using such a pump, when the ink pressure cleaning is performed, the pressure pump is reversed and forced when the positive pressure applied to the ink discharge nozzle 701 falls below the pressure necessary for discharging bubbles from the nozzle to the outside. Therefore, the residual pressure applied to the ink discharge nozzle 701 is reduced.
[0054]
FIG. 4 shows the positive pressure applied to the ink discharge nozzle 701 with respect to the time axis during the cleaning in this embodiment. A2 to D2 and T2 represent the operation process of the pressurizing pump 505, respectively A2: rotation in the pump pressurizing direction B2: pump stop C2: reverse pump rotation (suction operation)
D2: The internal pressure in the vicinity of the ink discharge nozzle 511 suddenly rises in the initialization pump pressurizing operation A2 at the rotational position. In this embodiment, the internal pressure is forced from the ink discharge nozzle 511 in the section: m where the internal pressure exceeds 30 [Kpa]. The ink is suddenly pushed out and all the nozzles are restored to a healthy state.
While the pump is stopped, the residual pressure is going to gradually decrease, but when the pump is reversely rotated at the timing near T: T2 and the suction operation is performed, the residual pressure is abruptly changed according to the waveform 401. Therefore, the amount of waste liquid (waste ink) can be reduced without impairing the cleaning effect.
[0055]
In this embodiment, the reverse rotation start timing of the pump is performed according to a sequence set in advance in the apparatus, but in the present invention, such means is not limited, for example, a pressure sensor is installed in the flow path, The detection value from the sensor may be fed back.
[0056]
However, in the case of the present embodiment, when the positive pressure applied to the ink discharge nozzle 511 is reduced by the reverse operation, on the contrary, an excessive negative pressure is applied to the ink discharge nozzle 511 so that the ink is not moved backward from the nozzle. There is a need to.
[0057]
In this embodiment as well, as described above, the reverse rotation start timing does not necessarily have to follow the present embodiment.
[0058]
FIG. 7 is an electrical block diagram of a recording apparatus embodying the present invention.
[0059]
A recorded image created on the host PC 700 (or an operation command such as printing start / end) is received by the interface controller 701 of the recording apparatus. The CPU 702 controls the recording apparatus, and performs control based on a program (corresponding to a flow described later) stored in the ROM 703.
[0060]
Under the control (instruction) of the CPU 702, the image captured via the memory controller 706 is subjected to processing such as color analysis, and bitmap data corresponding to each of the recording heads 501K to 501Y is developed in a VRAM (Video-RAM) 707, and temporarily. Memorized.
[0061]
The recording apparatus according to the present embodiment receives image information and operation commands by, for example, parallel communication (IEEE1284), USB (Universal Serial Bus), or 10 / 100Base-T (network), and the CPU 702 receives image information and operation commands. After analysis, it is expanded in the VRAM 707. The operation command is stored in the RAM 704.
[0062]
When the development of the bitmap data corresponding to each of the recording heads 501K to 501LM is completed and an operation command instructing the start of recording is received, the CPU 702 executes a recording process.
[0063]
Here, K: black, C: cyan, M: magenta, Y: yellow, LC: light cyan, and LM: light magenta are shown.
[0064]
Control of the entire recording apparatus is performed by the CPU 702 executing a control program (corresponding to a flow described later) written in the ROM 703.
[0065]
The EEPROM 704 is a non-volatile memory for writing setting values unique to the recording apparatus such as the number of the mounted recording heads, fine adjustment values for correcting the recording position (registration) deviation between the recording heads, or various modes. .
[0066]
Here, EEPROM (Electronic Erasable Programmable Read Only Memory).
[0067]
In the recording process, the head U / D motor 714 that drives the recording heads 501K to 501LM in the vertical direction via the input / output (I / O) port 712, the motor driving unit 713, and the nozzle unit 511 of the standby recording head are sealed. The capping motors 715 that drive the capping mechanism 502 for capping back and forth in the transport direction are mutually driven and controlled to move the recording heads 501K to 501LM from the capping position to the recording position.
[0068]
Next, driving of the driving circuit 1513 to the conveyance motor 1516 is started, and in parallel, the sheet feeding motor 718 is driven to pick up and separate the sheet, and deliver it to the conveyance unit.
[0069]
The leading edge detection sensor 721 provided upstream in the transport direction of the recording heads 501K to 501LM detects the leading edge position of the recording medium, and the recording start position is positioned below the ink ejection nozzle row of each recording head with reference to this position. When it reaches, reading of the image (recording) data of each of the recording heads 501K to 501LM stored in the VRAM 707 is started, and the data is transferred to the recording heads 501K to 501LM via the memory controller 706 to the recording head control circuit 720 for color recording. Is done.
[0070]
The downstream side paper detection sensor 119 monitors the passage state of the sheet P after the recording operation, and detects a paper jam or the like.
[0071]
The pressurization pump 505 and the waste ink recovery pump 507 according to the present invention operate by driving a pump motor 717. The recovery pump 507 may use a separate independent motor.
[0072]
The opening / closing of the pressurizing valve 520 according to the present invention is controlled by ON / OFF of the pressurizing valve solenoid 719.
[0073]
The operation flow of the CPU 702 relating to the first embodiment of the present invention will be described with reference to FIG.
[0074]
First, it is detected whether the recording head 501 is at the sealed cap position (S801). If the recording head 501 is at another position (S801-No), the recording head 501 moves to the cap position (S802).
[0075]
Then, the pressure valve solenoid is turned on, the pressure valve 520 is closed (S803), the pump motor is turned on, the pump 505 is driven, and the pressure recovery operation of the recording head is started. (S804) The ink is forced from each nozzle. Are exhausted.
[0076]
After the predetermined time has elapsed (when it is determined that the soundness of the nozzle has been recovered) (S805-Yes), the pressurizing valve solenoid is turned off (S806), and then the pump motor is also turned off (S807). The pressure drops rapidly.
[0077]
Accordingly, the amount of ink discharged thereafter is also rapidly reduced.
[0078]
When the above pressure recovery operation is completed, the ink on the nozzle surface of the recording head is wiped with a wiper blade (not shown), and the process ends.
[0079]
Although the pressure recovery is set as a predetermined time, a method of feeding back the pressure gauge or the like may be used. Next, the operation flow of the CPU 702 relating to the second embodiment of the present invention will be described with reference to FIG.
[0080]
First, it is detected whether the recording head 501 is at the sealed cap position (S901). If the recording head 501 is at another position (S901-No), the recording head 501 moves to the cap position (S902).
[0081]
Then, the pressurizing valve solenoid is turned on, the pressurizing valve 520 is closed (S903), and then the pump motor is turned on in the pressurizing direction to start driving the pump 505 and pressurizing and recovering the recording head (S904). Ink is forcibly discharged from the printer. When the piston 601 is at the top dead center, the pump motor once stops and waits.
[0082]
After a predetermined time has elapsed (when it is determined that the soundness of the nozzle has been recovered) (S905-Yes), when the pump motor is turned on in the suction direction and the piston 601 is pushed down, the positive pressure in the liquid chamber of the recording head suddenly increases. To drop.
[0083]
Accordingly, the amount of ink discharged thereafter is also rapidly reduced.
[0084]
Note that the pressurization valve solenoid may be turned off in accordance with the suction direction of the pump motor being turned on to promote a decrease in positive pressure.
[0085]
When the above pressure recovery operation is completed, the ink on the nozzle surface of the recording head is wiped with a wiper blade (not shown) (S908), and the process ends.
[0086]
Although the pressure recovery is set as a predetermined time, a method of providing a pressure gauge and feeding back the value may be used. Next, the operation flow of the CPU 702 relating to the third embodiment of the present invention will be described with reference to FIG.
[0087]
The pump motor used in this embodiment is, for example, a tube pump system shown in FIG.
[0088]
First, it is detected whether the recording head 501 is at the sealed cap position (S1001). If the recording head 501 is at another position (S1001-No), the recording head 501 moves to the cap position (S1002).
[0089]
Then, the pressurizing valve solenoid is turned on, the pressurizing valve 520 is closed (S1003), and then the pump motor is turned on in the pressurizing direction to drive the pump 505 and start the pressurization recovery operation of the recording head (S1004) Ink is forcibly discharged from the printer. The pump motor once stops and waits.
[0090]
After a predetermined time has elapsed (when it is determined that the soundness of the nozzle has been recovered) (S1005-Yes), the pressurization valve solenoid is turned off (S1006) and the pressurization valve is opened. When driven in the suction direction (S1007), the positive pressure inside the liquid chamber of the recording head rapidly decreases.
[0091]
Accordingly, the amount of ink discharged thereafter is also rapidly reduced.
[0092]
When the above pressure recovery operation is completed, the ink on the nozzle surface of the recording head is wiped with a wiper blade (not shown) (S1008), and the process ends.
[0093]
Although the pressure recovery is set as a predetermined time, a method may be used in which a pressure gauge or the like is provided inside and the value is fed back.
【The invention's effect】
As described above, according to the embodiment of the present invention, the recording head ink pressurization is performed to discharge air bubbles from the ink discharge nozzle of the print head to the outside or to restore the ink discharge nozzle that has been fixed to a healthy state. In cleaning,
By actively lowering the residual pressure after pressurization, the amount of waste ink consumed during pressure cleaning can be reduced without impairing the desired cleaning effect, which contributes to reducing the running cost of the printing apparatus. .
[0095]
[Brief description of the drawings]
FIG. 1 is a {time × pressure} correlation diagram according to the first embodiment of the present invention.
FIG. 2 is a {time × pressure} correlation diagram according to the second embodiment of the present invention.
FIG. 3 is a diagram showing a configuration example of a tube pump system.
FIG. 4 is a {time × pressure} correlation diagram according to the third embodiment of the present invention.
FIG. 5 is a diagram illustrating a configuration of an ink supply system and a flow path.
FIG. 6 is a schematic view of a reciprocating pump used in the present invention.
FIG. 7 is an electrical block diagram of a recording apparatus embodying the present invention.
FIG. 8 is an operation flow of ink pressure recovery according to the first embodiment.
FIG. 9 is an operation flow of ink pressure recovery according to the second embodiment.
FIG. 10 is an operation flow of ink pressure recovery according to the third embodiment.
FIG. 11 is a schematic diagram showing a conventional example of an ink supply and recovery system.
[Explanation of symbols]
501: Recording head 502: Capping mechanism 503: Ink cartridge 504: Atmospheric communication port 505: Pressure pump 511: Ink discharge nozzle 512: Liquid chamber 513: Filter 520: Pressure valve 601: Piston 603: Cam 604: Cylinder internal fluid Chamber 605: Suction valve 606: Discharge valve 700: Host PC
702: CPU
703: ROM
717: Pump motor 719: Pressure valve solenoid

Claims (11)

A recording head having a plurality of nozzles for ejecting ink;
A first ink path comprising an ink cartridge for storing ink, and a pressurizing pump for pressurizing and supplying ink from the ink cartridge to the recording head;
An ink supply / recovery mechanism comprising a second ink path including a valve from the recording head to the ink cartridge;
An ink supply / recovery mechanism for a recording head, comprising: valve opening means for driving the pressure pump after closing the valve and opening the valve after a predetermined time. The ink supply / recovery mechanism according to claim 1, further comprising an opening unit that opens at least one of the first ink path and the second ink path during a recording operation. The ink supply / recovery mechanism according to claim 1, further comprising a filter unit between the first and second ink paths and the recording head. 4. The ink supply / recovery mechanism according to claim 1, wherein a timing at which the valve is opened by the valve opening unit is immediately before or after the pressurizing pump is stopped. 4. The ink supply / recovery mechanism according to claim 1, wherein the valve opening means opens the valve when the positive pressure in the vicinity of the nozzle of the recording head falls below a predetermined value. 6. The ink cartridge according to claim 1, wherein the ink cartridge has an air communication port that can be opened and closed between the ink storage unit and the outside, and the air communication port communicates with the ink supply recovery mechanism during operation. Ink supply / recovery mechanism. 8. The ink supply / recovery mechanism according to claim 1, wherein the pressure pump is a reciprocating pump. 8. The ink supply / recovery mechanism according to claim 7, wherein the one-cycle pressurization capacity of the reciprocating pump is larger than a required ink amount satisfying the pressure recovery operation performance. 8. The ink supply / recovery mechanism according to claim 1, wherein the pressure pump is a tube pump system. The ink supply / recovery mechanism according to claim 9, wherein the pressurizing pump is driven and reversely rotated after a predetermined time. A recording apparatus comprising the ink supply / recovery mechanism according to claim 1.

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