JP3414605B2 - Ink jet recording apparatus and maintenance method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mounts an ink jet recording head and a sub tank on a carriage, and
The present invention relates to an inkjet recording apparatus that mounts an ink storage unit on a case side and supplies ink to the recording head from the ink storage unit via an ink supply path, and a maintenance technique therefor.

[0002]

2. Description of the Related Art An ink jet recording apparatus has an ink jet recording head for ejecting ink droplets from a pressure generating means mounted on a carriage and performs printing while receiving ink replenishment from an ink tank. An ink tank such as an ink cartridge is also mounted on the printer to simplify the structure by eliminating the need for a pump for pressure-feeding ink. On the other hand, as the performance of inkjet recording heads has improved dramatically, the dot density has dramatically increased, making it possible to print in full color and to allow bleeding on the recording medium to further improve printing quality. Efforts are being made to suppress this. As one of such means, a technique has been proposed in which an ink contains an emulsion or sugar to quickly form an ink droplet on a recording medium to prevent bleeding.

In the ink having such a film-forming property, there is a possibility that the fluidity to the recording head may be lowered by the porous body for suppressing the pressure fluctuation filled in the on-carriage type ink cartridge. As shown in Japanese Examined Patent Publication No. 4-43785, a carriage is equipped with a sub-tank that also functions as a pressure damper that partially includes a flexible film, and ink in an ink cartridge placed on a box is pumped to this sub-tank. A method of supplying ink to a recording head via a sub tank has been proposed.

According to this, not only can the ink be reliably supplied to the recording head irrespective of the characteristics of the ink such as the film forming property of the ink, but also the weight of the entire carriage can be reduced to achieve high-speed printing. Although there is an advantage that a large-capacity ink cartridge can be used and the ink replenishment cycle can be extended, the bubbles generated in the sub tank due to the reciprocating movement of the carriage intrude into the recording head and cause ink droplets for printing. There is a problem that it obstructs the discharge of. In order to solve such a problem, an ink supply system has been proposed in which a recording head, a sub-tank, and an ink cartridge are connected by a circulation channel to circulate ink and eliminate bubbles in the recording head. Since two channels, a forward flow channel and a return flow channel, are required between the ink cartridge and the ink cartridge, there is a problem that the flow channel structure for supplying ink becomes complicated.

In order to solve such a problem, the applicants of the present invention have established two reservoirs communicating with both sides of the pressure generating chamber,
An ink jet recording head having an ink supply port connected to the outside for each reservoir and a sub tank are mounted on the carriage, and an ink tank is provided on the case side.
An ink supply means for intermittently pressure-feeding the ink in the ink tank to the recording head is provided, and the ink is supplied to the recording head while reciprocally moving the ink between the ink tank and the sub tank so that the recording head serves as a relay point. Inkjet recording apparatus for

[0006]

According to such a configuration, although the flow channel configuration for ink supply can be simplified,
If the sub tank is left filled with ink for a long period of time, the ink solvent evaporates from the film that composes the sub tank, the viscosity of the ink in the sub tank rises, and the stability of ink ejection during printing is obtained. Even if the degassed ink is used, the degree of degassing of the ink in the sub tank is lowered due to the infiltration of gas into the sub tank. The ink deteriorated in this way not only impairs printing stability, but also causes ejection failure of printing. In order to prevent such inconvenience, it is a good idea to selectively discharge only the deteriorated ink in the sub-tank, but in the ink supply method with a single flow path as described above, the direction from the ink cartridge to the sub-tank is increased. The ink can be actively moved only in one direction, and it is impossible to discharge the ink in the sub tank. Of course, it is conceivable that the cartridge side is positively sucked through the recording head by suction or the like, but the configuration becomes complicated. In addition, although it may be considered that ink is sucked and discharged from the recording head that is a relay point, a large amount of ink suitable for printing is also discharged from the ink storage unit, which causes a waste of ink. The present invention has been made in view of the above problems, and an object thereof is to selectively discharge deteriorated ink in a sub tank while minimizing normal discharge of ink in a cartridge. It is an object of the present invention to provide an inkjet recording device capable of performing the above.

Another object of the present invention is to propose a maintenance method for recovering the ink droplet ejection capability suitable for the same apparatus.

[0008]

In order to solve such a problem, in the present invention, two reservoirs communicating with both sides of the pressure generating chamber, and a plurality of inks into which the inks respectively flow from the outside. A recording head that includes a supply port and that selectively ejects ink from a nozzle; a sub-tank that is configured at least partially with a flexible film and that includes a unit that detects a filling state of ink; the recording head; A carriage that mounts the sub-tank so that the sub-tank is located at a higher position than the recording head, and moves relative to the recording paper; and the recording head and the one ink supply port that are arranged outside the carriage. An ink storage unit that communicates with the sub-tank through the other ink supply port and an ink storage unit that communicates with the sub-tank through the other ink supply port. Ink supply means for pressure-feeding the ink of the storage means to the recording head, capping means for sealing the nozzle opening of the recording head outside the print area of the carriage, and sealing of the nozzle opening of the recording head by the capping means In this state, the ink supply unit is driven to pressure-feed the ink in the ink storage unit to the sub-tank via the recording head, and further after the ink full state is detected by the unit that detects the ink filling state. Maintain the pumped condition, and after a predetermined time
And a control means for stopping the drive of the ink supply means and releasing the sealing of the recording head by the capping means.

[0009]

[Action] above the internal pressure of the sub tank by pressurizing the ink storage means in a state of sealing the nozzles of the recording head
As the temperature rises , sub nozzles and sub tanks can be opened by opening the nozzle.
You spill a thickened of the recording head ink and air bubbles from the recording head.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments. FIG. 1 shows an embodiment of an ink jet recording apparatus of the present invention, in which reference numeral 1 is a carriage, which is supported by guide members 2 and 3 and is parallel to a rotary shaft 5 of a platen 4 described later. It is configured to move. Recording head 8 on carriage 1
And a sub-tank 10 for supplying ink to the recording head 8. In the recording head 8, one of two ink supply ports described later is connected to the ink cartridge 6 via a tube, and the other ink supply port is connected to the sub-tank 10 via a flow path 9.

In the non-printing area of the moving path of the recording head 8, the recording head 8 is ejected from a capping device 11 which will be described later and seals the nozzle opening surface of the recording head 8 and the recording head 8. A waste ink tank 12 that contains ink is provided.

The platen 4 holds the recording paper picked up by the pickup roller 14 from the paper feed tray 13 on its surface with the claw member 15, receives the ink droplets from the recording head 8 with the recording paper, and forms dots. Ejection port 1 while ink is dried by the built-in heater
6 is configured to be discharged.

The ink cartridge 6 includes a main body case 17
An ink supply needle is inserted by a lever 18 that can be operated from outside, and ink can be supplied to the recording head 8 via an ink tube 7 connected to this needle. Reference numeral 19 in the figure denotes an exhaust fan.

2, FIG. 3, FIG. 4, and FIG. 5 each show one embodiment of the above-mentioned ink jet recording head 8 by taking a color ink jet head as an example. In FIG. The nozzle plate is provided with a plurality of nozzle openings 21 and serves as a member for sealing one surface of a spacer 22 described later. Reference numeral 22 denotes a spacer, partition walls 23, 23, 23 are formed at equal intervals so as to separate adjacent nozzle openings 21, 21, 21, and the pressure generating chamber 24 communicating with the nozzle openings 21, 21, 21 ... , 24, 24, ..., One surface is sealed by the nozzle plate 20, and the other surface is sealed by the diaphragm 25.

On both sides of the pressure generating chambers 24, 24, 24, ..., Two reservoirs 26, 27 extending in the direction in which the pressure generating chambers 24 are arranged are provided, as shown in FIG. The ink can be transferred from the ink reservoir to the other reservoir 27 via the pressure generating chamber 24. The reservoirs 26 and 27 are provided with a first ink supply port 30 connected to the ink cartridge 6 via the tube 7 and a second ink supply port 31 connected to the sub tank 10.

Reference numeral 28 in the drawing denotes a piezoelectric vibrator, which is constituted by laminating electrodes and piezoelectric vibrating material in a sandwich shape so as to generate vibration in a longitudinal vibration mode.
At least the same number as 21, 21 is abutted on the vibrating plate 25 at the tip and fixed at the other end to the base 29, and the ink droplet is ejected from the nozzle opening 21 by being extended by the print signal.

FIG. 6 shows an embodiment of the capping device and its peripheral structure. In this embodiment, the recording head 8 is attached to the capping device 11.
A waste ink tank 12 for storing the ink discharged from the printer is provided, and both are disposed at positions outside the print area of the carriage 1 as shown in FIG. 7, and the capping device 11 faces the recording head 8. And the waste ink tank 12 is located below the capping device 11.

The capping device 11 will be further described. In FIG. 6, a cap member 40 for sealing the recording head 8 is configured by a silicone rubber or the like having chemical resistance to have a shape capable of sealing the nozzle opening.
It is attached to a cap member drive mechanism 41 which rotates in the directions indicated by arrows A and B by a cap member drive means 73 (FIG. 10) about the center 2. The drive mechanism 41 moves between the position where the cap member 40 abuts the recording head 8 and the retracted position, and guides the shaft 43 connected to the support member of the cap member 40 with the long groove 44 to move the crank 4
The rotation of 5 lowers the cap member 40 from the height at which it faces the recording head 8 to the blade 47 disposed in the waste ink tank 12 below.

With such a configuration, in the non-printing state,
When the cap member 40 is raised to a position facing the recording head 8 and the driving mechanism 73 rotates the driving mechanism 41 in the direction of arrow A to bring the driving mechanism 41 into contact with the recording head 8 and to release the recording head 8. The drive mechanism 41 is rotated in the direction of arrow B to form a gap between the drive mechanism 41 and the recording head 8, and when cleaning the nozzle openings 21, the crank 45 is rotated greatly to move the cap member 4 into a gap.
The rubbing operation and the wiping operation can be performed by lowering the wiper 46 provided on the upper part of 0 at a slight speed while contacting the nozzle plate 20.

When the cap member 40 is further lowered, the cap member 40 and the wiper 46 move to the blade 47.
The blade 47 moves the ink and ink residue adhering to the cap member 40 and the wiper 46 while elastically contacting the blade 47.
Can be wiped off by.

FIG. 8 shows an outline of the ink supply flow path to the ink jet recording apparatus constructed as described above, and the first ink supply port 30 of the recording head 8 mounted on the carriage 1 is shown. Is the end of the sub-tank 10 mounted on the ink bag 6a housed in the cartridge 6 by the tube 7 and the carriage 1 as well as the second ink supply port 3 of the recording head 8.
Connected to 1.

By forming such an ink supply channel, the liquid feed means, in this embodiment the cartridge 6 in the state where the nozzle opening 21 is sealed by the cap member 40.
When the air pump 50 that pressurizes the airtight space 6 b is pressurized, the ink bag 6 a is compressed and the ink flows into the first ink supply port 30 of the recording head 8 via the tube 7. The ink passes from the one reservoir 26 through the pressure generating chamber 24 and is discharged to the other reservoir 27, passes through the second ink supply port 31 from the reservoir 27, and passes through the sub-tank 1.
It flows into 0. In this process, air bubbles remaining in the reservoirs 26 and 27 and the pressure generating chamber 24, and the ink having a high concentration near the nozzle opening 21 are discharged to the sub tank 10, and the ink flowing from the cartridge 6 causes the nozzle opening 21 to flow. The pressure generating chamber 24 is washed.

When the sub-tank 10 is filled with ink and the pressure in the space of the sub-tank 10 rises, the air vent valve 63 overcomes the urging force of the spring 63a (FIG. 9) and opens to open only air to the atmosphere. Is released. Sub tank 10
When a predetermined amount of ink is filled in, the signal is output from the ink full sensor 66, the air pump 50 is stopped, and the air bleeding valve 63 is also closed by the biasing force of the spring 63a. After that, the ink in the sub-tank 10 flows into the recording head 8 due to the water head difference based on the height difference between the carriage 1 and the cartridge 6, and further flows back to the ink cartridge 6. When the backward flow of ink to the ink cartridge 6 progresses and the amount of ink in the sub tank 10 decreases, a signal is output from the ink empty sensor 64. As a result, the air pump 50 operates to pressurize the ink cartridge 6 and supply ink to the sub tank 10 via the recording head 8.

In this way, the reciprocating circulation between the ink tank 6 and the sub-tank 10 having the recording head 8 as a relay point is repeated, and the pressure generating chamber 24 of the recording head 8 and the reservoir 2 are
The nozzles 6, 27 and the nozzle opening 21 are washed with the ink of the ink cartridge 6 having a relatively low viscosity, and the density of the ink is adjusted to an optimum value for printing.

FIG. 9 shows an embodiment of a sub-tank suitable for constructing the above-mentioned ink supply path. In the figure, reference numeral 60 is a polymer or the like in which the upper portion 60a and the lower portion 60b are shaped like boats. With the base that also functions as the formed sealing part, 3
Silicon oxide is deposited on the surface of a flexible polymer film whose sides are sealed to form a silicon oxide layer, and the surface of the silicon oxide layer is laminated with a polymer film having excellent heat-welding properties. The opening of the light-transmitting bag body 61 is welded.

The base 60 has one end extending to the bottom of the bag 61 and an upper end having a connection port 62 connected to the ink supply port 31 of the recording head 8. The base 60 is connected to the upper space and is normally closed by a spring 63a. An air vent valve 63 for maintaining the valve state is provided.

A light transmitting region 61a is formed on the rear end side of the bag body 61, an ink empty sensor 64 is arranged therein, and one end 65a is fixed to the base body 60, and the central portion 6 is formed.
5b is elastically contacted with the bag body 61, an ink full detection plate 65 having a light shielding portion 65c formed at the other end is provided, and an ink full sensor 66 having an optical path is arranged at a position facing the light shielding portion 65c. .

FIG. 10 shows an embodiment of a system for controlling the ink supply operation and the capping operation. The control device 70 controls the maintenance command signal from the maintenance command switch 71 and the ink intake sensor. In response to signals from 64 and the ink full sensor 66, the air pump 50 for pressurizing the ink cartridge, the atmosphere opening valve 51, and the cap member driving means 73 are operated based on a flow chart described later, and the head driving means 72 performs flushing. Is configured to be output to the recording head 8.

Next, the operation of the apparatus thus constructed will be described with reference to FIG.
It will be described based on the flowcharts shown in FIG. (Initial filling operation) In order to maintain the quality of the recording head 8 and the sub tank 10, the recording device shipped from the factory is
A maintenance liquid, which does not contain pigments or dyes and has properties similar to those of the ink solvent, is filled, and the maintenance liquid evaporates slightly to increase its viscosity with the passage of time.

When a user who purchases the recording apparatus mounts the ink cartridge 6 and operates the switch in a form not normally used, for example, the power switch is turned on while pressing the cleaning switch 71, the controller 70 receives an initial filling command. It was judged that it was issued (step a in Figure 11),
The drive member 72 is operated to elastically contact the cap member 40 with the recording head 8 to seal the recording head 8 (FIG. 11, step B).

Next, the air pump 50 is operated (see FIG.
1 step c) The ink in the ink cartridge 6 is supplied to the recording head 8. As a result, ink flows into the sub tank 10 via the recording head 8. Sub tank 1
When a predetermined amount of ink flows into 0, the detection plate moves to the optical path of the ink full sensor 66, and the ink full sensor 66
Ink full signal is output from (Fig. 11 step
D). In this state, the control device 70 outputs a signal to the cap driving means 72 and records the cap member 40 at a stage when the timer is activated and the time T1 has elapsed without stopping the air pump 50 (step E in FIG. 11). The head 8 is separated from the head 8 (step F in FIG. 11), the air pump 50 is stopped, and the pressurization of the ink cartridge 6 is stopped (step 11 in FIG. 11).

As a result, the liquid in the sub-tank 10 flows back to the recording head 8 due to the high pressure of the ink that has been excessively injected from the ink full state in the sub-tank 10. Needless to say, in this state, the ink cartridge 6 is also pressurized to the pressure just before the pump is stopped,
The ink in the sub-tank 10 cannot flow back to the ink cartridge 6, and will flow out from the nozzle opening 21 that is open. As a result, the maintenance liquid of the recording head 8 and the sub tank 10 is mainly discharged from the nozzle opening 21.
Flows out from.

When the time T2 required for the pressure in the sub-tank 10 to return to the normal pressure due to the outflow of ink from the nozzle openings 21, for example, 10 seconds has elapsed (step S in FIG. 11), a flushing command is issued to the head drive means 72. Output. The head drive unit 72 applies a drive signal capable of generating a pressure higher than the pressure applied during printing by about 20% to all the piezoelectric vibrators 28 of the recording head 8. As a result, the pressure generating chamber 24 is pressurized with a high pressure, and even the maintenance liquid thickened during the circulation process of the recording apparatus is reliably discharged as droplets from the nozzle openings 21 (FIG. 1).
1 step). In this flushing operation,
An amount corresponding to 50 to 80% of the capacity of the sub tank 10, or an amount of ink in the sub tank 10 is 20 to
It is desirable to carry out until the reduction is about 50%. By this flushing operation, even the maintenance liquid adhering to the corner of the pressure generating chamber 24 of the recording head 8 is dissolved in the ink, or is discharged alone from the nozzle opening 21.

When the predetermined time T3 has elapsed (see FIG. 11)
The controller 70 stops the supply of the drive signal to the recording head 8 to stop the flushing operation (step S in FIG. 11). Next, the recording head 8 is sealed with the cap member 40 (step 11 in FIG. 11),
Then, the cap member 40 is separated from the recording head 8 to open the recording head 8 (step W in FIG. 11). Due to the mechanical pressure caused by the contact and separation of the cap member 40 with respect to the nozzle plate, the residue stuck to the nozzle opening 21 or the vicinity of the nozzle opening is physically peeled off,
Even if it is not peeled off, the adhesive force is reduced.

Then, the number of times M is incremented, and the process returns to the above step (i) again to execute the flushing operation. The process of bringing the cap member 40 into contact with the cap member 40 and then separating the cap member 40 and then performing the flushing operation is repeated a plurality of times, three times in this embodiment, and then the process returns to the first step (b) again, and the above-mentioned steps are performed. (B) to (f)
Is repeated multiple times, three times in this embodiment (step 11 in FIG. 11). By repeating the maintenance operation a plurality of times as described above, the recording head 8, the tube 7, the sub-tank 10
The maintenance liquid that had been filled up in the etc. is reliably discharged out of the route.

(Normal maintenance operation 1) When the cleaning switch 71 is pressed, the control device 70 determines that a maintenance command has been issued (step B in FIG. 12), operates the drive means 72, and causes the cap member 40 to move to the recording head 8. The recording head 8 is sealed by elastically contacting (FIG. 12, step B).

Then, the air pump 50 is operated (see FIG.
2 step c) The ink in the ink cartridge 6 is supplied to the recording head 8. As a result, ink flows into the sub tank 10 via the recording head 8. When a predetermined amount of ink flows into the sub tank, the detection plate moves to the optical path of the ink full sensor 66 and the ink full signal is output from the ink full sensor 66 (step d in FIG. 12).
In this state, the control device 70 activates the timer without stopping the air pump 50, and at the stage when the time T4 has elapsed (step E in FIG. 12), the cap drive means 7 is operated.
2 is output to separate the cap member 40 from the recording head 8 (step F in FIG. 12), and the air pump 50
To stop the pressurization of the ink cartridge 6 (step in FIG. 12).

As a result, the liquid in the sub-tank 10 flows back to the recording head 8 due to the high pressure of the ink that has been excessively injected from the ink full state in the sub-tank 10. Needless to say, in this state, the ink cartridge 6 is also pressurized to the pressure just before the pump is stopped,
The ink in the sub-tank 10 cannot flow back to the ink cartridge 6, and will flow out from the nozzle opening 21 that is open. As a result, the thickened ink in the sub-tank 10 and the recording head 8 is discharged to the outside of the system, and foreign matters and the like that hinder printing in the vicinity of the nozzle openings are washed away by the ink.

When the time T5 required for the pressure in the sub-tank 10 to return to the normal pressure due to the outflow of ink from the nozzle opening 21, for example, 10 seconds has elapsed (step 12 in FIG. 12), a flushing command is issued to the head drive means 72. Output. The head drive unit 72 applies a drive signal capable of generating a pressure higher than the pressure applied during printing by about 20% to all the piezoelectric vibrators 28 of the recording head 8. As a result, the pressure generating chamber 24 is pressurized with a high pressure, and even thickened ink is surely discharged as droplets from the nozzle openings 21 (step 12 in FIG. 12). In this flushing operation, ink flows into the recording head 8 from the sub tank 10 arranged at a high place,
The ink in the sub tank 10 is selectively discharged. The amount corresponding to 50 to 80% of the capacity of the sub tank 10 or the ink amount of the sub tank 10 is 20 to 20% when the ink is filled.
When it is reduced to about 50%, it becomes possible to fill the ink suitable for printing into the sub tank 10 by filling the ink described later.

At the stage when the predetermined time T6 has elapsed (see FIG.
The controller 70 stops the supply of the drive signal to the recording head 8 to stop the flushing operation (step 12 in FIG. 12). The first step again (b)
Then, the above steps (b) to (l) are repeated a plurality of times, in this embodiment, three times (FIG. 12, step e). In this way, by repeating the maintenance operation a plurality of times, the thickened ink in the recording head 8, the tube 7, and the sub-tank 10 is reliably discharged out of the path.

(Normal maintenance operation 2) When the cleaning switch 71 is pressed, the controller 70 determines that a maintenance command has been issued (step B in FIG. 13), operates the drive means 72, and causes the cap member 40 to move to the recording head 8. Then, the recording head 8 is sealed by elastically contacting (FIG. 13 step B). At this time, the driving means 73 brings the cap member 40 into contact with the nozzle plate 20 at a very low speed of about 1.0 to 2.0 mm / sec. Thereby, the nozzle opening 21
It is possible to prevent the meniscus formed on the substrate from being inadvertently destroyed.

Next, the air pump 50 is driven at high speed (step C in FIG. 13) to supply the ink in the ink cartridge 6 to the recording head 8. As a result, ink flows into the sub tank 10 via the recording head 8. Before a lapse of time T7, for example, 30 seconds from the start of ink supply (step D in FIG. 13), the detection plate moves to the optical path of the ink full sensor 66 and the ink full signal is output from the ink full sensor 66 (see FIG. 13). Step e),
In this state, the controller 70 does not stop the air pump 50, but additionally drives the pump 50 for the time T8 (step F in FIG. 13) to stop the pump 50 (step S in FIG. 13). As a result, the ink can be injected into the sub-tank 10 at a pressure that is higher by 0.15 to 0.3 × 10 5 Pascals than the atmospheric pressure. By injecting this ink, the bubbles invading the tube 7, the pressure generating chamber 24 of the recording head 8 and the reservoirs 26 and 27 are flushed with the ink into the sub-tank 10 and are collected in the upper space of the sub-tank 10 to generate an overpressure. Minutes,
That is, the air is discharged from the air vent valve 63 to the outside of the system with a pressure of about 0.15 to 0.3 × 10 5 Pascal.

The control device 70 outputs a signal to the cap driving means 72 to separate the cap member 40 from the recording head 8 (step S in FIG. 13), and moves downward in this state. As a result, the wiper 46 of the cap member 40 descends while contacting the nozzle plate 20 to rub the nozzle plate 20 (step 13 in FIG. 13).
The rubbing operation is performed by moving the cap member 40 to 5 to 10 mm /
It is carried out by descending at a speed of about a second and is extremely effective in removing solidified ink adhering to the surface of the nozzle plate 20, paper dust and the like. At the same time, the ink in the sub-tank 10 arranged on the high place side selectively flows out from the nozzle opening 21, so that the thickened ink in the sub-tank is discharged out of the system.

At the stage where the rubbing operation has been performed Po a predetermined number of times (step S in FIG. 13), a predetermined time T9 has elapsed (step S in FIG. 13), and wiping is executed (step S in FIG. 13). By this wiping operation, ink droplets adhering to the vicinity of the nozzle openings 21 are wiped off to prevent flight deflection of ink droplets during printing. When the wiping operation is completed, the control device 70 causes the drive unit 73 to form a gap with the recording head 8 and largely rotates the crank 45 to cause the cap member 40 and the wiper 46 to move to the waste ink. The blade 47 of the tank 12 is elastically contacted and lowered. As a result, the ink adhering to the cap 40 and the ink dust and paper dust adhering to the wiper 46 are scraped off by the blade 47.

The controller 70 drives the air pump 50 at a low speed (step 13 in FIG. 13) at a stage when the predetermined time T10 has elapsed after the wiping operation is completed (step 13 in FIG. 13) and fills the sub-tank 10 with ink. . When a predetermined time T11 has elapsed after the ink is filled (step 13 in FIG. 13), the pump 50 is stopped (step in FIG. 13) and the maintenance work is completed. By driving the pump 50 at a low speed in this way, the ink pressure of the sub-tank 10 and the recording head 8 is set to a level that does not destroy the meniscus and is slightly higher than the atmospheric pressure, for example, 0.02 to 0.0.
The nozzle opening 2 is maintained at a high level of 4 × 10 5 pascals.
The ink is filled to the extent that printing can be performed without causing the ink to leak from 1.

When no signal is output from the ink full sensor 66 within the predetermined time T7 (step D in FIG. 13), the pump 50 is stopped (step S13 in FIG. 13), and when the predetermined time T12 elapses. (FIG. 13 step S), the cap member 40 is separated from the recording head 8 to open the recording head 8 (FIG. 13 step), and the ink end is displayed (FIG. 13 step).
D) The work is completed without executing the maintenance operation. The unnecessary operation of the air pump 50 and the unnecessary pressurization of the cartridge 6 are prevented.

[0047]

As described above, according to the present invention,
Ink storage means with nozzles of recording head sealed
By increasing the pressure , the internal pressure of the sub tank is increased.
The thickened ink and bubbles in the sub tank and recording head.
Can be ejected from the recording head, and for printing near the nozzle openings
It is also possible to wash away foreign matter that becomes an obstacle with ink .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a printer to which an ink supply system of the present invention is applied.

FIG. 2 is a diagram showing the structure of a cross section in the horizontal direction at the center of the ink supply port of an embodiment of the ink jet recording head used in the same apparatus.

FIG. 3 is a front view showing an embodiment of an ink jet recording head used in the above apparatus with a nozzle plate removed.

FIG. 4 is a diagram showing a structure of a vertical section taken along an axis passing through a nozzle opening.

FIG. 5 is a plan view showing an example of a spacer that forms a common ink chamber.

FIG. 6 is a diagram showing an example of a capping device.

FIG. 7 is a diagram showing positions of a cap member and a waste ink tank.

FIG. 8 is a flow path configuration diagram showing an outline of an ink supply system of the present invention.

9A and 9B are a front view and a C view, respectively, showing an embodiment of a sub tank built in a carriage.
It is sectional drawing in the -C line.

FIG. 10 is a configuration diagram showing an embodiment of a system for ink supply and maintenance of the present invention.

FIG. 11 is a flowchart showing an operation of initial filling in the operation of the above apparatus.

FIG. 12 is a flowchart showing a maintenance operation among the operations of the above apparatus.

FIG. 13 is a flowchart showing a second embodiment of the maintenance operation of the operations of the above apparatus.

[Explanation of symbols]

1 carriage 4 Platen 6 ink cartridges 7 tubes 8 recording head 10 sub tank 30, 31 Recording head ink supply port 50 air pump 73 Drive means

Front page continuation (72) Inventor Kazuhiko Hara 3-5 Yamato, Suwa, Nagano Seiko Epson Co., Ltd. (72) Inventor Hiroe Niimura 3-5 Yamato, Suwa, Nagano Seiko Epson Corporation In-house (56) References JP-A-6-8467 (JP, A) JP-A-6-143602 (JP, A) International Publication 95/031335 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 2/175 B41J 2/165

Claims (12)

(57) [Claims] 1. A recording head comprising: two reservoirs communicating with both sides of a pressure generating chamber; and a plurality of ink supply ports into which the ink flows from the outside, respectively, wherein ink is selectively ejected from nozzles. , A sub-tank at least a part of which is made of a flexible film and provided with means for detecting the ink filling state, and the recording head and the sub-tank are mounted so that the sub-tank is located at a higher position than the recording head And a carriage that moves relatively to the recording paper, and is arranged outside the carriage, and communicates with the recording head through the ink supply port through the one ink supply port and the other ink supply port. An ink storage unit that communicates with the sub-tank via the ink storage unit; an ink supply unit that pressure-feeds the ink in the ink storage unit to the recording head; A capping means for sealing the nozzle opening of the recording head outside the printing area of the carriage; and the ink storage means by driving the ink supply means with the nozzle opening of the recording head sealed by the capping means. After the ink of (1) is pressure-fed to the sub-tank via the recording head and the ink full state is detected by the means for detecting the ink filling state,
The pressure supply state is further maintained, and after a predetermined time, the ink is supplied.
An inkjet recording apparatus comprising: a control unit that stops the driving of the supply unit and releases the sealing of the recording head by the capping unit. 2. The ink jet recording apparatus according to claim 1, wherein the means for detecting the ink filling state of the sub tank is a displacement amount detecting means for detecting the pressure or the displacement amount of the sub tank. 3. The ink jet recording apparatus according to claim 1, wherein the sub-tank has a region that allows light to pass through the flexible film, and detects the presence or absence of ink based on the amount of light transmitted through the region. 4. A recording head comprising: two reservoirs communicating with both sides of a pressure generating chamber; and a plurality of ink supply ports into which the ink flows from the outside, respectively, and which selectively ejects ink from nozzles. , A sub-tank, at least a part of which is made of a flexible film, having a means for detecting the filling state of ink, and the recording head and the sub-tank are mounted so that the sub-tank is at a higher position than the recording head. And a carriage that moves relatively to the recording paper, and is arranged outside the carriage, and communicates with the recording head through the ink supply port through the one ink supply port and the other ink supply port. An ink storage unit that communicates with the sub-tank via the ink storage unit; an ink supply unit that pressure-feeds the ink in the ink storage unit to the recording head; A method for maintaining an ink jet recording apparatus, comprising: a capping unit that seals a nozzle opening of the recording head outside a print area of the carriage, wherein the capping unit seals the nozzle opening of the recording head. A step of driving the ink supply means to drive the ink of the ink storage means to the sub-tank via the recording head to the sub-tank even after ink full is detected by the means for detecting the ink filling state; 2 steps and stop the drive of the ink supply means
And a fourth step of releasing the sealing of the recording head by the capping means and a drive signal is supplied to the recording head to eject ink droplets from the nozzle opening after a predetermined time has elapsed. Maintenance method. Wherein said predetermined time definitive fourth step, maintenance method according to claim 4 which is the time until the ink injected into the sub-tank returns to atmospheric pressure. 6. In the fourth step, the amount of ink ejected from the nozzle opening is 50 to 8 of the sub tank capacity.
The maintenance method according to claim 4, wherein the amount corresponding to 0% or the ink capacity of the sub-tank is reduced to 20 to 50% when the ink is filled. 7. The maintenance method according to claim 4, wherein the first to fourth steps are repeated a plurality of times. 8. A recording head comprising two reservoirs communicating with both sides of a pressure generating chamber, and a plurality of ink supply ports into which the ink flows from the outside, respectively, and which selectively ejects ink from nozzles. , A sub-tank, at least a part of which is made of a flexible film, having a means for detecting the filling state of ink, and the recording head and the sub-tank are mounted so that the sub-tank is at a higher position than the recording head. And a carriage that moves relatively to the recording paper, and is arranged outside the carriage, and communicates with the recording head through the ink supply port through the one ink supply port and the other ink supply port. An ink storage unit that communicates with the sub-tank via the ink storage unit; an ink supply unit that pressure-feeds the ink in the ink storage unit to the recording head; Capping means for sealing the nozzle opening of the recording head outside the printing area of the carriage,
A maintenance method for an ink jet recording apparatus, comprising: a wiping means for cleaning the recording head, wherein a first step of sealing a nozzle opening of the recording head by the capping means and driving the ink supply means. A second step of further feeding the ink of the ink storage means to the sub-tank via the recording head to the sub-tank even after the ink full state is detected by the means for detecting the ink filling state; and driving the ink supply means. Let it stop
From the second step of removing the sealing of the recording head by the capping means, the fourth step of cleaning the recording head by the wiping means, and the second step of removing the ink of the ink storage means by the ink supply means. A maintenance method comprising a fifth step of supplying the sub tank via the recording head at a low pressure. 9. The maintenance method according to claim 8, wherein the cleaning in the fourth step is a rubbing operation and a wiping operation. 10. The maintenance method according to claim 9, wherein the wiping operation is performed after the rubbing operation is repeated a plurality of times. 11. The maintenance method according to claim 8, wherein the first to fifth steps are repeated a plurality of times. 12. The maintenance method according to claim 8, wherein when the ink full is not detected even after a predetermined time elapses due to the ink supply operation in the second step, the ink supply unit is stopped. "