JPH10211720A - Ink jet recording device and jet-recovering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the jet-recovering of high suction recovery performance even when a long multi-recording head is used by closing a valve at the time of suction recovery of the recording head, actuating a suction pump to increase the negative pressure in a pressure chamber and releasing the valve in the above state. SOLUTION: A waste ink flow path 45 is shut off by closing a release valve 46 after the completion of the capping operation, and a suction pump 45 is actuated in the above state to set the atmospheric pressure in a pressure chamber 47 to be negative lower than the atmospheric pressure without applying the negative pressure to a nozzle section of a recording head. At that time, the pressure in the pressure chamber 47 is set so that the pressure in a suction cap 42 is to be (the pressure -Pr) lower than (the pressure -Pn) for recovering the suction of the recording head 1, when the valve 46 is released. The negative pressure in the pressure chamber 47 is raised while being sensed by a pressure sensor, and when the pressure in the pressure chamber become (the set pressure -Pr) and the valve 46 is released, a nozzle face is closed by the suction cap 42, and (the negative pressure -Pr) is applied uniformly all nozzles on the nozzle section of the recording head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for performing an ink jet recovery process for preventing and recovering from clogging of ink discharge ports of a print head and defective ink discharge, and a jet recovery in such an ink jet recording apparatus. It relates to a processing method.

[0002]

2. Description of the Related Art FIG. 20 is a schematic plan view of an embodiment of an ink jet recording apparatus according to the prior art. An ink jet recording head used in an ink jet recording apparatus generally includes a discharge port for recording liquid droplets, a nozzle for supplying a recording liquid to the discharge port, and an energy acting portion provided on a part of the nozzle. There is provided an energy generating means for generating energy for forming droplets to act on the recording liquid in the action section.

As the energy generating means, one using an electromechanical transducer such as a piezo element, irradiating an electromagnetic wave such as a laser, absorbing the ink liquid in the portion to generate heat, and generating heat by the action of this heat generation. A device that discharges droplets or a heating element such as an electrothermal converter is known.

In particular, an ink jet recording head which uses an electrothermal transducer as an energy generating means and discharges droplets from a discharge port by thermal energy has the following advantages.

[0005] a) It is possible to easily arrange a discharge port for discharging recording liquid droplets to form flying liquid droplets at a high density so as to easily adopt a structure suitable for performing recording with high resolution. it can. b) The structure can be easily made compact. c) It is possible to make full use of the advantages of IC technology and micro-machining technology, which have been remarkably improved in recent semiconductor technology and reliability in the production thereof, and by using these technologies, the length and surface area can be increased. (Two-dimensional), multiple outlets,
Densification is easier, mass production is possible, and manufacturing costs are lower.

[0006] An ink jet recording head having a multi-layered discharge port manufactured through a semiconductor manufacturing process using an electrothermal transducer as an energy generating means includes:
A liquid path corresponding to each discharge port is provided, an electrothermal converter is provided for each of the liquid paths, and a recording liquid is supplied from a common liquid chamber communicating with each liquid path. Have been.

FIG. 21 shows a perspective view of one configuration of such an ink jet recording head. This ink jet recording head includes an electrothermal transducer 3, an electrode 4, a nozzle 5, and a top plate 6 formed on a substrate 2 through semiconductor manufacturing process steps such as an etching method, a vapor deposition method, and a sputtering method. I have.

The recording ink 12 is supplied from an ink tank (not shown) into the common liquid chamber 8 of the recording head 1 through an ink supply pipe 20a. In the figure, reference numeral 9 denotes a connector for an ink supply pipe. Ink 1 supplied into the common liquid chamber
2 is supplied into the liquid passage 10 by capillary action, and is stably held by forming a meniscus on the discharge port surface 11 at the front end of the liquid passage.

Here, by energizing the electrothermal transducer 3,
The recording liquid on the electrothermal transducer 3 is heated, a bubbling phenomenon occurs, and ink droplets are ejected from the ejection port surface 11 by the energy of the bubbling.

[0010] In such an ink jet recording apparatus, the viscosity of the recording ink is increased due to the evaporation or temperature drop of the recording ink in the ink discharge ports of the recording head, bubbles are mixed in the nozzles of the recording head, and the recording head discharges. Discharge recovery means for preventing and recovering from clogging and ink discharge failure due to adhesion of foreign matter to the surface and the like have been implemented.

FIG. 19 and FIG. 20 show examples of ejection recovery means in a conventional ink jet recording apparatus, which are disclosed in Japanese Patent Application Laid-Open Nos. 61-158467 and 62-116152.

Hereinafter, description will be made with reference to the drawings. FIG.
The ejection recovery means shown in FIG. 9 is based on an ink circulation system. The ink supply tank 20 filled with the recording ink 12 and the recording head 1 are connected to each other by a supply tube 20a for ink supply having an ink supply means 18 and a supply tube 20b for ink circulation.
Are connected by

During the ejection recovery process of the recording head 1, the ink pressure feeding means 18 is driven to drive the ink pressure feeding pipe 2.
The recording ink in the recording head 0a is pressure-fed in the direction of arrow A and supplied to the common liquid chamber 8 of the recording head 1 to apply pressure to the nozzles of the recording head, thereby discharging the recording ink from the nozzles of the recording head under pressure. It is. By this pressurized discharge, the above-mentioned thickened ink, bubbles, and foreign substances adhering to the ink ejection port surface are removed.

The remaining ink, which has been pressure-fed into the common liquid chamber 8 of the recording head 1 and has not been discharged from the nozzles, is pressure-fed in the direction of arrow B through the circulating ink supply tube 20b. Collected inside.

Such an ink circulation type ejection recovery means has high ejection recovery performance from clogging of a recording head and an ink ejection failure state, and in particular, is capable of removing air bubbles that have entered the common liquid chamber 8 of the recording head 1. Therefore, it has been adopted in an ink jet recording apparatus for high-speed recording and large-screen recording using a recording head having a long common liquid chamber 8 having a recording nozzle number of 256 nozzles or more and having a long length L.

The ejection recovery means shown in FIG. 23 is based on a suction recovery method, and is an example of a recording head in which an ink cartridge 33 containing an ink absorber 34 containing the recording ink 12 is connected via a connector 9. Is shown. The recording ink discharged from each nozzle 5 during the recording operation of the recording head 1 is supplied from the ink absorber 34 of the ink cartridge 33 to the ink supply path 41 every time the recording ink in the common liquid chamber 8 is consumed by the recording operation. Is supplied into the common liquid chamber 8 of the recording head via the connector 9 so that the recording operation of the recording head 1 can be stably continued.

By the way, as described above, the recording ink in the nozzles of the recording head 1 is thickened due to evaporation or low temperature, bubbles are mixed in the nozzles of the recording head 1 or the common liquid chamber, If foreign matter adheres to the ejection port surface of the head, stable ejection by the recording head cannot be performed. Therefore, in the suction recovery method, the suction cap 42 having an ink absorber and connected to the suction pump 37 via the ink discharge tube 44 is connected to the outside of the recording nozzle of the discharge port surface 11 of the recording head 1 via the cap sealing rubber. After bringing the print head 1 into close contact with the area, the suction pump 37 is driven to set the pressure Ps in the closed space between the suction cap 42 and the discharge port surface of the print head to a negative pressure state equal to or lower than the atmospheric pressure. The ejection recovery processing of the recording head is performed in which the recording ink is sucked and discharged from the nozzles and collected in the waste ink tank 35.

Since such a suction recovery type ejection recovery means has a simple structure and is advantageous for cost reduction, it has been used in many small ink jet recording printers and the like.

In recent years, there has been an increasing demand for high-speed recording, low cost, and downsizing of ink jet printers, and high-speed recording using a recording head having 256 or more recording nozzles is possible and low cost, small size. It has been desired to commercialize an ink jet recording printer.

[0020]

However, if the above-described ink circulation type ejection recovery means is employed, especially in the case of C, M, Y, and Bk full color printing,
The ink pressurizing pump must be provided with four colors as ink pressurizing means, and a large ink pressurizing pump must be used to increase the pressure of the ink to be pressurized in order to improve the recovery performance. . As a result, there is a problem that the apparatus configuration becomes large and it is difficult to reduce the cost in terms of cost.

Further, if the ink recovery method of the ink suction system as described above is employed, the more the number of recording nozzles is increased to 256 or more, the more the suction recovery performance is reduced, and particularly the length is long. There is a problem that it is difficult to remove air bubbles that have entered the common liquid chamber 8 by suction, and when an attempt is made to perform ejection recovery by a suction method using a multi-nozzle recording head, the amount of ink drawn out differs depending on the nozzle position. .

For example, when suction is performed from the center of the suction cap or supply is performed from the center of the common liquid chamber as shown in FIG. 26, the distance between the ink supply port and the nozzle located at the center A of the recording head is short. In addition, since the resistance is the lowest, ink is easily drawn out. Conversely, since the distance from the ink supply port is long at the nozzle portions B at both ends and the resistance is the highest, the ink is hardly drawn out and the suction recovery property is low. Therefore, until the pressure at which the suction of the nozzles of the nozzle portions B at both ends can be recovered is reached.
In order to increase the negative pressure in the suction cap, it is necessary to continue suction for a considerable time from the start of suction. Since a large amount of waste ink comes out, there is a problem that the amount of waste ink increases.

FIG. 27 shows, as another example, the case where ink is supplied from both ends of the common liquid chamber using two ink supply paths. In this case, the amount of waste ink that comes out at the time of suction recovery is reduced. A, C> B, and the amount of waste ink from the center decreases. FIG. 28 shows a case where ink can be supplied only from one end of the common liquid chamber due to the configuration of the head or the main body. In this case, the amount of waste ink that comes out at the time of recovery is C>B> A, and A makes it difficult for waste ink to come out.

FIG. 24 is a graph showing the relationship between the pressure P in the suction cap and the operation time t of the suction pump at this time. FIG. 25 is a graph showing the operation time t of the suction pump and the waste ink amount l.
It is a graph which shows the relationship of (ell). First, in the graph of FIG. 24, the suction pressure in the suction cap required to recover the nozzles of the recording head that has become longer is set to -Pn, and a negative pressure area equal to or lower than the pressure -Pn is set as a long head recoverable pressure area. I do.
In the conventional suction recovery operation, time t1 is required to obtain the pressure -Pn in the long head recoverable pressure region, and-
After the pressure of Pn is obtained, suction is performed at a pressure equal to or higher than the pressure -Pn from t1 for a time necessary for nozzle recovery, that is, the operation of the negative pressure generating means ends at t2 of the print head recovery end time. The operation of the negative pressure generating means ends at time t2, but the pressure in the cap returns to the atmospheric pressure over the time from t2 to t3 because the pressure in the suction cap or the waste ink discharge tube is negative. .

Therefore, the suction of ink from the nozzle portion is continued until time t3. If this time relationship is taken directly to FIG. 25, the amount of waste ink in the hatched portion C discharged from the nozzles from the start of suction to t1 before the suction recovery at the pressure-Pn at which the suction recovery of each nozzle portion is possible. The amount of waste ink flowing out of the nozzle becomes wasteful waste ink, and the hatched portion D discharged from the nozzle from the operation end time t2 of the negative pressure generating means to the time t3 until the pressure in the suction cap returns to the atmospheric pressure. The waste ink amount is also waste ink which is wasted due to the residual negative pressure in the cap after the suction recovery is completed.

Further, when such a long recording head is a head integrated with a cartridge, the ink capacity of the ink cartridge in the carriage must be reduced. As described above, when the capacity of the ink tank is reduced, when high-speed continuous printing is performed using a recording head having 256 or more recording nozzles, the recording ink in the ink cartridge runs out in a short time, and the ink is discharged in a short time. You have to change the cartridge.

In order to eliminate such a decrease in the suction recovery performance and an increase in the amount of waste ink, a gate that can be opened and closed is provided in the ink supply path as disclosed in JP-A-4-10555 and JP-A-7-32601, and the suction operation is performed. There is a method in which the gate is sometimes closed, the negative pressure in the suction cap is increased, and then the gate is opened to perform suction. However, if the gate is provided in the ink supply path as described above, (1) When the gate is provided in the carriage,
(2) Two configurations when the gate is not mounted on the carriage are considered, and the two configurations have the following problems.

(1) When the gate is provided on the carriage,
In the case of a color printer, gates for four colors of C, M, Y, and Bk must be installed in the ink supply path.
There is a problem that leads to an increase in size. (2) When the gate is not mounted on the carriage, a tube routing system is provided to route a tube (supply pipe) from the recording head on the carriage and connect with the ink tank provided on the main body side as shown in FIG. As for the inkjet recording device, this problem can be solved if the gate is not mounted on the carriage.However, the routed tube moves in conjunction with the carriage, so that the gate cannot be provided, and the tube is located near the ink tank farthest from the recording head. A gate must be provided in the supply path of the vehicle. In this case, the longer the drawn tube becomes 50 cm and 100 cm,
The negative pressure effect in the supply diminishes.

Even if such a recovery method of recovering after increasing the negative pressure effect is employed, it is difficult to remove small-volume bubbles adhered to the inner wall of the ink amount path in the recording head. It cannot be removed from the inner wall in the ink flow path by the second recovery, or b) Even if it can be removed, in the process of removing air bubbles from the nozzle portion of the recording head, the air bubbles may be removed to another place in the ink flow path. In some cases, it may adhere again. In such a case, air bubbles remain in the print head even after the print head recovers, and the air bubbles that could not be removed expand due to the temperature rise during printing of the print head, causing ejection failure, or could not be removed. There is a problem that air bubbles become a resistance of ink supply during printing and ink supply becomes insufficient. To solve such a problem, setting a high negative pressure at the time of suction recovery or increasing the number of times of suction recovery of the print head causes an increase in the amount of waste ink.

As another problem, as described above, in an ink jet recording apparatus having a tube drawing system supply system, the ink jet recording tube (ink supply pipe) that connects the ink tank and the recording head is placed in a long-term storage state. In some cases, air bubbles enter the ink supply tube through the wall of the tube, or bubbles enter the ink supply tube due to vibration or impact.

These bubbles are guided to the recording head by ink refill during printing by the recording head, and lead to printing failure. Therefore, it is necessary to remove bubbles by recovery. In order to remove these bubbles by the recovery of the suction type recording head, all the ink in the routing tube must be sucked and discharged together with the bubbles. Therefore, there is a problem that a large amount of waste ink must be used for one recovery of the print head.

If it is attempted to remove the bubbles by the recovery of the recording head of the circulation system, the bubbles can be returned to the ink tank through the tube in which the bubbles are circulated, so that all the ink in the circulation tube is made waste ink. However, since the air bubbles must be circulated through the ink supply tube (pipe) 20a to the common liquid chamber 8 of the recording head to the ink supply tube (pipe) 20b in FIG. There is a problem that the amount of waste ink discharged from the nozzles of the recording head during circulation is increased.

To solve this problem, Japanese Patent Application Laid-Open No. 56-758
66, as disclosed in JP-A-56-75867, the ink supply tube 20a shown in FIG.
The ink supply tube 20b is provided with an openable and closable valve. To recover the recording head nozzle, the valve is closed and the pump is operated to forcibly apply ink pressure to the nozzle to perform recovery. With the nozzle portion of the recording head sealed by the capping means, the waste ink is prevented from coming out of the nozzle by the ink circulation, the valve of the ink supply tube 20b is opened to perform the ink circulation, and the bubbles are returned to the ink tank. Although a method is disclosed, in this case, as described above, the configuration in which the valve is provided in the ink supply path requires the provision of valves for four colors in the case of full color, so that the apparatus configuration becomes large, and the cost is high. This leads to problems that lead to

[0034]

In order to solve the above-mentioned problems, an ink jet recording apparatus according to the present invention comprises a plurality of discharge ports which communicate with a common liquid chamber and discharge ink supplied from the common liquid chamber. A cap for covering the plurality of discharge ports, a suction pump for performing suction from the plurality of discharge ports when the cap covers the plurality of discharge ports, and ink supplied to the common liquid chamber and the supply liquid chamber. A pressure pump for circulating ink between an ink tank for storing
A pressure chamber and a valve for opening and closing the suction path are arranged in a suction path connecting the cap and the suction pump, and switching between suction by the suction pump and circulation by the pressure pump. And an ink jet recording apparatus.

Further, the ink jet recording apparatus of the present invention comprises a cap for covering an ejection port for ejecting ink,
A suction pump for performing suction from the discharge port when the cap covers the discharge port; and opening and closing the pressure chamber and the suction path in a suction path connecting the cap and the suction pump. An ink jet recording apparatus is provided with a valve for performing the operation, and ejects ink from the ejection port in response to a cleaning pulse when suction is performed by the suction pump.

(Operation) According to the present invention, the operation of applying the pressure vibration wave of the recording ink to the discharge nozzle and the common liquid chamber by utilizing the bubbling phenomenon of the recording head at the time of suction recovery, and applying a high negative pressure to the entire discharge nozzle Since the ejection recovery is performed by combining the operation of instantaneously applying the
Even if a long multi-nozzle print head with more than nozzles is used, it is possible to perform suction recovery with high reproducibility of the print head, reduce the size and cost of the ink jet printing apparatus, and reduce the amount of waste ink at the time of ejection recovery. Reductions can be achieved.

Further, according to the present invention, by having two recovery operations of suction recovery and circulation recovery, at the time of suction recovery, the discharge recovery is performed by momentarily applying a high negative pressure to the entire discharge nozzle area. Even if a long multi-nozzle recording head with 256 or more recording nozzles is used,
The suction recovery with high reproductive performance of the recording head can be performed, and the circulation recovery is performed by sealing the nozzle portion of the recording head by capping means against bubbles in the ink supply tube and returning to the ink tank by ink circulation. By the operation, the size and cost of the inkjet recording apparatus can be reduced, and the amount of waste ink at the time of ejection recovery can be reduced.

[0038]

Next, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic perspective view of an ink jet recording apparatus common to Embodiments 1 to 3 of the present invention, and FIG. 2 is a schematic plan view of an ink jet recording apparatus common to Embodiments 1 to 3 of the present invention. It is.

In FIG. 1, a continuous paper or cut paper recording medium is pinched between a recording head 1 and a platen roller 23 for forming and holding a recording surface of a recording medium such as paper (not shown). The sheet is conveyed while being pressed against the platen roller 23 (not shown). The recording head 1 is mounted on a carriage 21, and is serially driven in two directions, SA and SB, along two guide rails 24a and 24b. In the process, recording on a recording medium is performed. The carriage 21 includes a belt 29 and a pulley 28a provided between pulleys 28a and 28b.
Is connected to the shaft 27 of the motor 26 through the
Are driven in the SA and SB directions in accordance with the rotation of.

The recording head 1 includes, for example, yellow (Y),
Magenta (M), cyan (C) and black (Bk)
And four recording units corresponding to the four colors. Y,
The recording units for recording M, C, and Bk are provided with ink supply paths independently, and each of the ink tubes 20
Ink tank 1 via Y, 20M, 20C, 20Bk
Yellow, magenta, cyan, and black inks are supplied from 9Y, 19M, 19C, and 19Bk.

Capping means 22 and suction cap 42
Is provided outside the recording image area of the recording head 1, and the ejection recovery means by the suction cap 42 moves the carriage 21 mounted with the recording head 1 to the home position HP, and then the suction cap 42 faces the recording head. In this state, the operation is performed after the suction cap 42 moves in the direction of arrow f and comes into contact with the ejection surface of the recording head 1.

As shown in the schematic plan view of FIG. 2, a waste ink discharge tube 45 serving as a waste ink flow path is connected to the suction cap 42, and the openable / closable valve 46 and the pressure chamber 4 are provided.
7. Connected to the waste ink tank 50 via the suction pump 48. The operation timing of the openable / closable valve 46 is determined after the suction cap comes into contact with the ejection surface of the recording head 1.
6 is closed, the waste ink flow path 45 is shut off, and the suction pump 48 is operated in that state, so that the pressure P in the pressure chamber 47 is reduced to a negative pressure equal to or lower than the atmospheric pressure, and the negative pressure effect in the pressure chamber 47 is reduced. At the height, the valve 46 is opened, and the recording ink, the thickened ink, the dust and the like of the nozzle portion 5 of the recording head 1 are removed by suction.

Next, the discharge recovery operation of the suction system according to the first embodiment of the present invention will be described with reference to the flowchart of FIG. First, as described above, the carriage 21 is moved to the home position to face the suction cap 42 (operation A). In a state where the suction caps 42 are opposed to each other, the suction cap 42 is brought into contact so as to seal the ejection surface of the recording head 1 (operation B), and the capping operation ends. After the capping operation is completed, the openable / closable valve 46 is closed to shut off the waste ink flow path 45 (operation C). In this state, the suction pump 48 is operated (operation D). By operating the suction pump 48, the waste ink flow path 45 is connected to the valve 4.
6, the pressure in the pressure chamber 47 can be reduced to a negative pressure equal to or lower than the atmospheric pressure without applying a negative pressure to the nozzle portion 5 of the recording head 1. At this time, the pressure chamber 47
Is set such that when the valve 46 is opened, the pressure in the suction cap 42 becomes equal to or lower than the pressure -Pn at which the recording head 1 can perform suction recovery. The pressure chamber 47 increases the negative pressure while detecting with the pressure sensor 52 or the like (operation E), and opens the valve 46 (operation F) when the pressure in the pressure chamber reaches the set pressure −Pr. Thus, since the nozzle surface of the recording head is sealed with the suction cap, the negative pressure -Pr capable of recovering the suction of the nozzle portion of the recording head can be applied almost uniformly to all the nozzles.

After completion of the suction recovery of the nozzle portion of the recording head,
The operation of the suction pump is stopped (operation G), and the suction cap 4
2 when the pressure in the tank 2 returns to the atmospheric pressure.
From the nozzle surface of the recording head 1 (operation H). After opening the suction cap, the suction pump is operated again to remove the waste ink remaining in the suction cap 42 and the waste ink flow path 45 into the waste ink tank 50. This operation is performed when the waste ink remains in the suction cap and the waste ink flow path.
Is changed depending on the amount of waste ink, and the amount of waste ink and the recoverability vary. In the above operations E and F, the pressure in the pressure chamber 47 is managed by the pressure sensor 52 and the like. However, the pressure in the pressure chamber can be managed by defining the operation time of the suction pump 48.

Next, the relationship between the pressure in the cap 42 and the recovery time when the recovery is performed by the suction recovery method of the present embodiment is shown in FIG. In the suction recovery method of this embodiment, the negative pressure of the pressure chamber 47 is applied to the nozzle portion 5 of the recording head 1 sealed with the suction cap 42 at the moment when the valve 46 is opened. It drops sharply to the pressure -Pr described above. Therefore, there is no need for waste ink corresponding to the recovery time and the suction pressure from the closing of the valve 46 shown in FIG. 24 to the time t1, and the waste ink amount in the hatched portion C shown in FIG. 25 can be reduced. Since the ink of the nozzle unit 5 of the recording head 1 is sucked and discharged from the moment when the pressure is applied to the nozzle unit 5, the pressure gradually returns to the atmospheric pressure after reaching the peak -Pr. However, since the suction pump continues to operate, the return of the pressure is not so remarkable. For this reason, as shown in FIG. 4, the pressure in the cap, which is going to return to the atmospheric pressure, is maintained in the long head recoverable pressure region, that is, −, during the period from ta to tb until the recovery of the nozzle portion of the recording head is sufficiently completed. If the negative pressure below Pn is maintained,
Recovery of the nozzle portion of the recording head can be sufficiently performed.

Therefore, as shown in FIG.
The peak of the pressure in the cap and the operation time t of the suction pump are set so as to be n, and the operation of the suction pump 48 ends at time tb. At time tb, the suction pump 48 is stopped, but the pressure chamber and the waste ink tube are in a negative pressure state. The suction of the ink from the unit 5 is continued.

FIG. 5 is a graph showing the relationship between the recovery time and the amount of waste ink in this embodiment. The recovery time t is the same as the recovery time t shown in FIG. It is. From this graph, the hatched portion D ′ indicating the amount of waste ink sucked during the period from the end of the operation of the negative pressure generating means to the time when the pressure in the suction cap returns to the atmospheric pressure corresponds to the hatched portion D ′ in FIG. For the shaded area D, the volume of the pressure chamber and the amount of recording ink are drawn,
Since the amount of waste ink and the recovery time of the hatched portion C in FIG. 25 can be reduced, the amount of waste ink is 13 in the suction recovery method of this embodiment.
(L3) to lc (Lc), the recovery time can be reduced from t3 to tc, the amount of waste ink is small, and the printhead recovery time can be shortened.

In the present invention, the recovery of the recording head is performed by combining the operation of applying a recording head cleaning pulse to the electrothermal transducer of the recording head during the suction recovery operation. The combination of the suction recovery operation and the operation of applying the recording head cleaning pulse to the electrothermal transducer of the recording head is based on the bubble bubbling phenomenon that occurs when the recording head cleaning pulse is applied to the electrothermal transducer of the recording head. The pressure oscillation wave (crosstalk) transmitted through the generated ink is used to weaken the adhering force of the small bubbles adhering to the inner wall of the nozzle and the common liquid chamber, and a suction recovery operation is performed in that state to perform the suction recovery operation, thereby performing the inner wall of the nozzle and the common liquid chamber. It can improve the performance of removing small bubbles adhering to the surface and improving the recovery performance.

With respect to the timing for applying the cleaning pulse, the cleaning pulse is applied to the recording head before the suction recovery operation as shown in FIG.
A pressure oscillation wave (crosstalk) is generated in the nozzle and the common liquid chamber due to a bubble bubbling phenomenon, and suction recovery and operation are started in a state where the adhesion of small bubbles adhering to the nozzle and the common liquid chamber wall is weakened. The cleaning pulse is continuously applied to the electrothermal transducer during the suction recovery operation to prevent the air bubbles that have moved due to the suction recovery from adhering to the inner wall of the common liquid chamber from adhering to the nozzle portion. The cleaning pulse is ended at the same time as the end of the suction recovery or after a lapse of a predetermined time from the end of the suction recovery, so as to prevent the bubbles on the inner wall of the common liquid chamber, which have been moved by the ink pressure at the time of the suction recovery, from adhering to the nozzle portion. ing.

Next, the recording head cleaning pulse used in the present invention will be described with reference to FIG. The recording head cleaning pulse used in this embodiment is different from the recording head driving pulse when the recording head is performing printing on the recording medium, and has no relation to the printing on the recording medium. The degree of freedom can be given to the pulse width, the pulse voltage, the pulse frequency, and the bubble foaming timing to the extent that there is no damage. Since the purpose of the recording head cleaning pulse is to apply vibration to the bubbles attached to the inner wall of the nozzle and the common liquid chamber as described above, the bubbling at this time causes the ink to vibrate in the nozzle and the common liquid chamber. Conveying foam is desirable.

FIG. 7A shows a recording head drive pulse during printing on a recording medium. FIG. 7B shows the result of changing the pulse width, and FIG. 7C shows the result of changing the pulse voltage. By using the pulse for the recording head cleaning pulse in this way, it is possible to increase the foaming volume of the bubble that foams on the surface of the electrothermal transducer, and to transmit a vibration having a larger amplitude to the nozzle and the common liquid chamber. Become. In the case of FIG. 7D, it is also possible to change the frequency of the pressure wave by changing the driving frequency of the recording head to change the number of times of bubble bubbling.

Further, as shown in FIG. 8, each nozzle is changed over time by combining the pulse width of the cleaning pulse, the pulse voltage and the driving frequency, and an interference wave that beats the pressure vibration wave in the head liquid chamber is generated. By causing the generation, the suction recovery property of the present invention can be further improved. Furthermore, by setting the timing of the nozzle to be foamed to a mode different from that of the recording head drive pulse when the recording head is printing on the recording medium, the nozzle is foamed at a timing at which the wave is easily transmitted to the common liquid chamber. It is also possible to devise such that vibrations are effectively given by bubbles adhering to the inner wall of the common liquid chamber. That is, as shown in FIG. 9, for example, when printing is performed on a recording medium, after foaming is performed with nozzles 1, 3, 5, and 7 in order to prevent crosstalk, 2, 4, 6 , No. 8 nozzle is foamed, but in the recording head cleaning pulse, all the nozzles are foamed all at once or foamed at a timing shifted from 1, 2, 3, 4, 5 to 5 By effectively transmitting the wave into the nozzle and the common liquid chamber, the effect of the present invention of removing attached bubbles can be improved.

Second Embodiment Next, a second embodiment will be described with reference to the flowchart of FIG. 10 and the graph of FIG. 11 showing the relationship between the suction time and the pressure in the suction cap. Example 2
The object of the present invention is to further reduce the waste ink amount and the suction recovery time in the first embodiment. The difference from the first embodiment is that, in the first embodiment, after the operation of the suction pump is completed, the pressure in the suction cap is reduced to the atmospheric pressure, and then the cap is opened. In the second embodiment, as shown in FIG. At the point that the valve opened in the operation F is closed again at the end of the operation of the suction pump,
This operation can reduce the amount of waste ink in the hatched portion D 'in FIG. 5 and the time required for suction recovery.

In the first embodiment, since the valve is kept open from the start of the suction recovery, the pressure -Pr corresponding to the volume of the hatched portion X + Y in FIG. In the second embodiment, the openable valve is closed at the suction pump operation end time tb after the recovery is completed, and the negative pressure applied to each nozzle of the print head is only the pressure -Pr corresponding to the volume of the hatched portion X. Since the time required for the internal pressure to return to the atmospheric pressure can be reduced, the amount of recording ink drawn from the nozzle portion of the recording head decreases. FIG. 11 is a graph showing the effect at this time in terms of the suction time and the pressure fluctuation in the cap. In the first embodiment, from the end of the operation of the negative pressure generating means until the pressure in the suction cap returns to the atmospheric pressure, from tb. Although a time of tc was required, it can be seen that in Example 2, the time was shortened from tb to td. This operation can reduce the time required for suction recovery and the amount of waste ink. After this operation, as shown in FIG. 10, the suction cap is opened in the operation H, the valve is opened again in the operation I, the negative pressure generating means is operated, and the waste ink in the suction cap is discharged to the waste ink tank. I do.

Third Embodiment Next, a description will be given of a third embodiment. In Example 3, suction recovery is performed at a higher negative pressure,
This also reduces the amount of waste ink and the recovery time. This will be described with reference to the flowchart of FIG. 12 and the graph of FIG. 13 showing the relationship between the suction time and the pressure in the suction cap.
As shown in FIG. 12, in the third embodiment, after the suction pump is operated in the operation D in FIGS. 3 and 10 in the flowcharts of the first and second embodiments, the pressure is confirmed in the operation E, and the pressure chamber is checked. When the pressure reaches the set pressure, the operation of the suction pump is stopped at that time and the valve is opened.

This will be described in more detail with reference to FIG.
When the pressure in the pressure chamber after the valve is closed is changed to the pressure in the suction cap when the valve is opened, as shown in FIG.
r so that the pressure -Pt becomes lower than the pressure -Ps of the pressure chamber.
Is set. After the valve is closed, the pressure in the cap rapidly drops to the set pressure -Pt, as in the first and second embodiments. Thereafter, since the operation of the suction pump is stopped, the pressure in the suction cap tends to rapidly return to the atmospheric pressure at the same time as the printing ink is drawn out from the nozzles of the printing head. If the pressure inside the suction cap is kept within the long head suctionable pressure region of -Pn or less for the time required for the recovery of the recording head by this setting, the recording head can be recovered. Therefore, as shown in FIG. 13, the pressure -Pt in the suction cap is set so that the internal pressure of the suction cap can be kept at -Pn or less for the time from td to te, which is the time required for the suction recovery of the recording head. I just need.

During the suction recovery time, the set pressure in the suction cap starts suctioning at a pressure -Pt lower than the set pressure -Pr in the first and second embodiments. Therefore, although the pressure quickly returns to the atmospheric pressure, the time for the suction recovery from ta to tb in FIG. 4 or FIG. 11 is not required, and the suction recovery can be performed in the time from ta to tb. Therefore, the set pressure -Pt in the cap is set so that the pressure in the cap becomes -Pn at the time te, and the time te
To complete the recovery of the recording head, the openable valve is closed at time te so that no more waste ink is discharged. Subsequent processing of the suction cap and the waste ink in the waste ink flow path is the same as in the second embodiment.

FIG. 14 is a diagram showing the relationship between the amount of waste ink and the recovery time, and the recovery time is the same as the time relationship in FIG. From FIG. 14, it can be seen that the waste ink amount is reduced from lc to lf in the first embodiment, and the suction time is reduced from td to tf in the second embodiment. Therefore, the third embodiment has the effects of reducing the suction recovery time and improving the suction recovery performance at a high suction pressure.

The cleaning pulse application operation performed simultaneously with the suction recovery operation in the second and third embodiments is described below.
The timing may be changed as shown in FIGS. 15 and 16 according to the shortened time.

(Embodiment 4) FIG. 17 is a schematic perspective view of an ink jet recording apparatus according to Embodiment 4 of the present invention, and FIG. 18 is a schematic plan view of an ink jet recording apparatus according to Embodiment 4 of the present invention. In FIG. 17, between the recording head 1 and a platen roller 23 for forming and holding a recording surface of a recording medium (not shown) such as paper, a recording medium in the form of continuous paper or cut paper is pinched by a pinch roller (not shown). ) By platen roller 2
3 while being conveyed. The recording head 1 is mounted on a carriage 21, and is serially driven in two directions, SA and SB, along two guide rails 24a and 24b. In the process, recording on a recording medium is performed. The carriage 21 has two pulleys 28a and 2
The motor 26 is connected to a shaft 27 of a motor 26 via a belt 29 and a pulley 28a provided between the motor 26 and the shaft 8b.

The recording head 1 includes, for example, yellow (Y),
Magenta (M), cyan (C) and black (Bk)
And four recording units corresponding to the four colors. Y,
The recording units for recording M, C, and Bk are provided with ink supply paths independently, and each of the ink tubes 20
Ink tank 1 via Y, 20M, 20C, 20Bk
Yellow, magenta, cyan, and black inks are supplied from 9Y, 19M, 19C, and 19Bk.

The ink is stored in the ink tanks 19Y, 19M, 1
From 9C and 19Bk, the ink pressurizing pumps 18Y, 1
The ink supply tubes (pipe) 20aY, 20aM, 20aC, 20aBk by 8M, 18C, 18Bk
Are sent to the recording heads of the respective colors. After the supplied ink fills the recording head, it passes through an ink return tube (pipe) 20b and is again supplied to the ink tanks 19Y and 19B.
Collected in M, 19C and 19Bk. In FIG. 17, for the sake of simplicity, the yellow return tube 20b
Only illustrated.

Capping means 22 and suction cap 42
Is provided outside the recording image area of the recording head 1, and the ejection recovery means by the suction cap 42 moves the carriage 21 mounted with the recording head 1 to the home position HP, and then the suction cap 42 faces the recording head. In this state, the operation is performed after the suction cap 42 moves in the direction of arrow f and comes into contact with the ejection surface of the recording head 1.

As shown in the schematic plan view of FIG. 18, a waste ink discharge tube 45 serving as a waste ink passage is connected to the suction cap 42, and the openable / closable valve 46, the pressure chamber 47, and the suction pump 48 are provided. Is connected to the waste ink tank 50 via the. The operation timing of the openable / closable valve 46 is as follows:
After the suction cap comes into contact with the ejection surface of the recording head 1, the valve 46 is closed, the waste ink flow path 45 is shut off, and the suction pump 48 is operated in this state to reduce the atmospheric pressure P in the pressure chamber 47 to the atmospheric pressure. When the negative pressure in the pressure chamber 47 is increased, the valve 46 is opened, and the recording head 1
The recording ink, thickened ink, dust and the like of the nozzle section 5 are removed by suction.

In the fourth embodiment, the recording head is recovered by switching between suction recovery and circulation recovery. Hereinafter, its use and effects will be described. In a supply system that supplies ink to a print head by drawing a tube into the main body of an ink jet printing apparatus as shown in FIG. 17, recovery of the print head includes recovery of the nozzle portion of the print head and long-term storage in the drawn tube. And two types of recovery, that is, a recovery that removes air bubbles that have penetrated the air.

There are various problems in the recovery of the nozzle portion of the recording head and the recovery of air bubbles in the routing tube as described in the above-mentioned problem to be solved by the present invention.
Switching between the suction recovery and the circulation recovery according to the present invention is effective in reducing the amount of waste ink at the time of removing bubbles generated in the routed tube or reducing the size of the ink pressurizing pump used for ink circulation. be able to.

In the fourth embodiment, when it is necessary to remove dust and bubbles from the nozzle portion of the recording head, the removal of dust and bubbles from the nozzle portion of the recording head is performed by suction recovery, and bubbles are generated in the routing tube. In this situation, the bubbles are returned to the ink tank by circulation recovery. By this switching, only the nozzle portion of the print head needs to be recovered in the suction recovery, so that the amount of waste ink used for recovery can be reduced.In the recovery of circulation, the nozzle of the print head is sealed by the cap at the time of bubble circulation. Since the ink is circulated in the closed state, the bubbles can be circulated and recovered without discharging the waste ink (there may be a small amount of the waste ink depending on the volume inside the cap). Further, since the pump used for circulation only needs to have a performance capable of circulating air bubbles, it is not necessary to use a large pump, and a small and weak pump can be used, which leads to downsizing of the main body.

The discharge recovery operation of the suction method of the fourth embodiment is the same as the operation of the first embodiment described with reference to the flowchart of FIG. Again, this Example 4
Will be described with reference to the flowchart of FIG. First, as described above, the carriage 21 is moved to the home position to face the suction cap 42 (operation A). In a state where the suction caps 42 are opposed to each other, the suction cap 42 is brought into contact so as to seal the ejection surface of the recording head 1 (operation B), and the capping operation ends. After the capping operation is completed, the openable / closable valve 46 is closed to shut off the waste ink flow path 45 (operation C). In this state, the suction pump 48 is operated (operation D). By operating the suction pump 48, the waste ink flow path 45
Therefore, the pressure in the pressure chamber 47 can be reduced to a negative pressure equal to or lower than the atmospheric pressure without applying a negative pressure to the nozzle portion 5 of the recording head 1. At this time, the pressure in the pressure chamber 47 is set so that the pressure in the suction cap 42 when the valve 46 is opened becomes equal to or lower than the pressure -Pn at which the recording head 1 can recover suction. The pressure chamber 47 increases the negative pressure while detecting with the pressure sensor 52 or the like (operation E), and opens the valve 46 (operation F) when the pressure in the pressure chamber reaches the set pressure −Pr. Thus, since the nozzle surface of the recording head is sealed with the suction cap, the negative pressure -Pr capable of recovering the suction of the nozzle portion of the recording head can be applied almost uniformly to all the nozzles.

After completion of the suction recovery of the nozzle portion of the recording head,
The operation of the suction pump is stopped (operation G), and the suction cap 4
2 when the pressure in the tank 2 returns to the atmospheric pressure.
From the nozzle surface of the recording head 1 (operation H). After opening the suction cap, the suction pump is operated again to remove the waste ink remaining in the suction cap 42 and the waste ink flow path 45 into the waste ink tank 50. This operation is performed when the waste ink remains in the suction cap and the waste ink flow path.
Is changed depending on the amount of waste ink, and the amount of waste ink and the recoverability vary. In the above operations E and F, the pressure in the pressure chamber 47 is managed by the pressure sensor 52 and the like. However, the pressure in the pressure chamber can be managed by defining the operation time of the suction pump 48.

FIG. 4 shows the relationship between the pressure in the cap 42 and the recovery time when the recovery is performed by the suction recovery method of this embodiment. In the suction recovery method of this embodiment, the negative pressure of the pressure chamber 47 is applied to the nozzle portion 5 of the recording head 1 sealed with the suction cap 42 at the moment when the valve 46 is opened. It drops sharply to the pressure -Pr described above. Therefore, there is no need for waste ink corresponding to the recovery time and the suction pressure from the closing of the valve 46 shown in FIG. 24 to the time t1, and the waste ink amount in the hatched portion C shown in FIG. 25 can be reduced. Since the ink of the nozzle unit 5 of the recording head 1 is sucked and discharged from the moment when the pressure is applied to the nozzle unit 5, the pressure gradually returns to the atmospheric pressure after reaching the peak -Pr. However, since the suction pump continues to operate, the return of the pressure is not so remarkable. For this reason, as shown in FIG. 4, the pressure in the cap, which is going to return to the atmospheric pressure, is maintained in the long head recoverable pressure region, that is, −, during the period from ta to tb until the recovery of the nozzle portion of the recording head is sufficiently completed. If the negative pressure below Pn is maintained,
Recovery of the nozzle portion of the recording head can be sufficiently performed.

Therefore, as shown in FIG.
The peak of the pressure in the cap and the operation time t of the suction pump are set so as to be n, and the operation of the suction pump 48 ends at time tb. At time tb, the suction pump 48 is stopped, but the pressure chamber and the waste ink tube are in a negative pressure state. The suction of the ink from the unit 5 is continued.

FIG. 5 is a graph showing the relationship between the recovery time and the amount of waste ink in the present embodiment. On the same scale as in FIG. 21, the recovery time t is the same as the recovery time relationship in FIG. It is. From this graph, the hatched portion D ′ indicating the amount of waste ink sucked in after the operation of the negative pressure generating means ends until the pressure in the suction cap returns to the atmospheric pressure corresponds to the hatched portion D ′ in FIG. For the shaded area D, the volume of the pressure chamber and the amount of recording ink are drawn,
Since the amount of waste ink and the recovery time in the hatched portion C in FIG. 21 can be reduced, the amount of waste ink is 13 in the suction recovery method of this embodiment.
(L3) to lc (Lc), the recovery time can be reduced from t3 to tc, the amount of waste ink is small, and the printhead recovery time can be shortened.

The ink supply for the suction recovery method of this embodiment is performed on both sides of the common liquid chamber and on one side (in the system shown in FIG. 2, the ink pump 18 is connected to the ink supply tube 20a).
The ink supply from one side or the ink supply from both sides is changed depending on whether the ink is blocked or opened. However, the ink supply position and the like are not specified, but the print head conditions (ink supply, common liquid supply) are not specified. If the long head suctionable pressure -Pn is changed depending on the chamber shape, nozzle resistance, etc., and the set pressure Pm of the pressure chamber, the time t, etc. are set according to -Pn, even if the conditions of the recording head are changed, The suction recovery can be performed with the effect of the embodiment.

Next, with reference to FIGS. 17 and 18 again, a description will be given of the recovery operation of the circulation system used for discharging the bubbles in the ink supply tube to the ink tank according to the present embodiment. First, the carriage 21 is moved to the home position and is opposed to the suction cap 42 as in the suction recovery method described above. In a state where the recording head 1 is opposed to the suction cap 42, the suction cap 42 is brought into contact so as to seal the ejection surface of the recording head 1, and the capping operation is completed.

After the capping operation is completed, the openable / closable valve 46
Is closed, and the waste ink flow path 45 is shut off. In this state, the ink pressurizing pump 18 is operated for a time during which bubbles in the ink supply tube 20 can be sufficiently returned to the ink tank 19.
During the operation of the ink pressurizing pump, the nozzle portion of the recording head is in contact with the cap 42, and the waste ink flow path 45 connected to the cap 42 is closed by the valve 46. Only a small amount of waste ink comes out from one nozzle (the smaller the volume of the cap, the less waste ink comes out). Therefore, the bubbles are discharged to the ink tank 19 via the ink supply tube 20a to the common liquid chamber 8 of the recording head 1 to the ink supply tube 20b by the ink pressurizing pump 18 in FIG. 18 with the recording head capped. . By the above operation, the bubbles in the ink supply tube can be circulated and discharged to the ink tank with a small amount of waste ink.

(Embodiment 5) Embodiment 5 is a modification of Embodiment 4 and relates to an ink circulation system. FIG.
As shown in FIG. 9, the ink supply tube (pipe) 20a
A buffer 53 for trapping air bubbles therein is provided. Here, the buffer 53 is a tube (pipe) connected to a sealed chamber in which ink and air are interposed, so that bubbles generated in the ink supply tube 20a in the region m indicated by a cross in FIG. Since the bubbles are trapped in the buffer 53 by the movement in the circulation recovery or the movement by the ink refill, the bubbles generated in the area m do not need to be circulated and returned to the ink tank 19. Therefore, the ink circulation time can be reduced.

(Other Embodiments) In Embodiments 4 and 5, at the time of suction recovery, the same suction recovery operation as that described in Embodiments 2 and 3 can be performed instead of the above-described suction recovery operation. .

[0078]

As described above, according to the present invention,
An ink jet recording head that has a plurality of recording nozzles for discharging ink and performs recording by discharging ink onto a recording medium; At the time of contact, a suction cap which comes into contact with the outside area of the nozzle port on the nozzle surface of the recording head to form a sealed space, and the suction cap comes into contact with the recording head and sucks the recording ink in the nozzle of the recording head. A suction pump for performing ejection recovery by means of an ink jet printing apparatus provided with a pressure chamber and a valve that can be opened and closed in a waste ink flow path between the suction cap and the suction pump in the ink jet printing apparatus, closes the valve when the print head suction recovers, By operating the suction pump, the negative pressure in the pressure chamber is increased, and by opening the valve in that state, the print head is recovered, and a high negative pressure is discharged during suction recovery. The suction recovery operation for ejection recovery by momentarily applying the nozzle throughout, even with multi-nozzle recording head long such number of recording nozzles 256 above the nozzle, can highly suction recovery performance ejection recovery,
It is possible to obtain an ink jet recording apparatus capable of reducing the size and cost of the ink jet recording apparatus and reducing the amount of waste ink at the time of ejection recovery.

The present invention further combines the above-described suction recovery operation with the operation of applying vibration (crosstalk) utilizing the bubbling phenomenon of the recording head to the discharge nozzle and the common liquid chamber at the time of suction recovery. An ink jet recording apparatus that can reduce the amount of waste ink at the time and can effectively remove bubbles can be obtained.

Further, with respect to bubbles generated in the ink flow path such as an ink supply tube connecting the ink jet recording head and the ink tank and a common liquid chamber of the recording head, the ink is circulated by an ink pressurizing pump for circulating the ink. In the meantime, the nozzle section is sealed with a cap with the waste ink flow path closed by a valve, minimizing the amount of waste ink emitted during ink circulation, miniaturizing the inkjet recording device, It is possible to obtain an ink jet recording apparatus that can achieve a reduction in cost and can reduce the amount of waste ink at the time of recovery from ejection.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration of Embodiments 1 to 3 of an ink jet recording apparatus of the present invention.

FIG. 2 is a schematic plan view of an ink jet recording apparatus used in Examples 1 to 3.

FIG. 3 is a flowchart illustrating the operation of the first embodiment;

FIG. 4 is a diagram illustrating a relationship between a pressure and a recovery time according to the first embodiment.

FIG. 5 is a diagram illustrating a relationship between a recovery time and a waste ink amount in the first embodiment.

FIG. 6 is a chart showing the timing of applying a cleaning pulse in each embodiment.

FIG. 7 is a diagram illustrating types of cleaning pulses used in each embodiment.

FIG. 8 is a diagram illustrating pulses that are time-changed by combining a pulse width of a cleaning pulse or a pulse voltage and a driving frequency used in each embodiment.

FIG. 9 is a schematic plan view showing a nozzle portion of a recording head used in each embodiment.

FIG. 10 is a flowchart illustrating the operation of the second embodiment of the present invention.

FIG. 11 is a diagram showing a relationship between pressure and recovery time according to a second embodiment of the present invention.

FIG. 12 is a flowchart illustrating the operation of the third embodiment of the present invention.

FIG. 13 is a diagram showing the relationship between pressure and recovery time according to a third embodiment of the present invention.

FIG. 14 is a diagram illustrating a relationship between a recovery time and a waste ink amount according to the third embodiment of the present invention.

FIG. 15 is a chart showing the timing of applying a cleaning pulse when the second embodiment of the present invention is used.

FIG. 16 is a chart showing the timing of applying a cleaning pulse when the third embodiment of the present invention is used.

FIG. 17 is a schematic perspective view illustrating a configuration of an inkjet recording apparatus according to a fourth embodiment of the present invention.

FIG. 18 is a schematic plan view of an ink jet recording apparatus used in Example 4.

FIG. 19 is a schematic plan view of an ink jet recording apparatus used in Example 5.

FIG. 20 is a schematic perspective view showing a conventional inkjet recording apparatus.

FIG. 21 is a schematic plan view showing a conventional ink jet recording head.

FIG. 22 is a schematic plan view for explaining recovery means of a conventional ink jet recording head.

FIG. 23 is a schematic plan view for explaining recovery means of a conventional ink jet recording head.

FIG. 24 is a diagram showing the relationship between pressure and recovery time in a conventional ink jet recording apparatus.

FIG. 25 is a diagram illustrating a relationship between a recovery time and a waste ink amount in a conventional inkjet recording apparatus.

FIG. 26 is a schematic plan view for explaining a configuration of a conventional ink jet recording head and a suction cap.

FIG. 27 is a schematic plan view for explaining a configuration of a conventional ink jet recording head and a suction cap.

FIG. 28 is a schematic plan view for explaining a configuration of a conventional ink jet recording head and a suction cap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Substrate 3 Electrothermal transducer 4 Electrode 5 Nozzle 6 Top plate 8 Common liquid chamber 29 Belt 33 Ink cartridge 34 Ink absorption 35 Waste ink tank 37 Suction pump 41 Ink supply path 42 Suction cap 9 Connector 10 Liquid path 11 Discharge Outlet surface 12 Ink 18 Ink pressure feeding means (pump) 19 Ink tank 20 Ink supply pipe 43 Seal rubber for cap 44 Ink discharge tube 45 Waste ink flow path 46 Openable valve 47 Pressure chamber 48 Suction pump 51 Nozzle 21 Carriage 22 Capping means 23 Platen Roller 24 Guide rail 26 Motor 27 Axis 28 Pulley 52 Pressure sensor 53 Buffer

Claims (34)

[Claims] 1. A cap for covering a discharge port for discharging ink, and a suction pump for performing suction from the discharge port when the cap covers the discharge port. An ink jet recording apparatus, comprising: a suction path connecting the suction pump; and a pressure chamber and a valve for opening and closing the suction path. 2. The ink jet recording apparatus according to claim 1, wherein said pressure chamber is provided between said valve and a suction pump. 3. The ink jet recording apparatus according to claim 1, wherein the valve is closed when the recording head provided with the discharge port recovers the suction, and the suction pump is operated to reduce the negative pressure of the pressure chamber. An ink jet recording apparatus wherein the suction pump is continuously operated to perform suction recovery when the valve is opened in that state. 4. The ink jet recording apparatus according to claim 1, wherein the valve is closed and the suction pump is operated when the recording head provided with the discharge port recovers the suction, thereby reducing the negative pressure of the pressure chamber. An ink jet recording apparatus, wherein the operation of the suction pump is stopped when the set pressure is increased and the valve is opened. 5. The ink jet recording apparatus according to claim 1, wherein after suction recovery by the suction pump is completed, waste ink in the cap is discharged into a waste ink tank by the suction pump. apparatus. 6. The ink jet printing apparatus according to claim 1, wherein the valve is closed and the suction pump is operated when suction recovery of the print head provided with the discharge port is performed. To increase the negative pressure of the pressure chamber,
In this state, the valve is opened to recover the print head, and after the suction recovery of the print head is completed, the valve is closed again to reduce the negative pressure in the cap. 7. A cap communicating with the common liquid chamber and covering a plurality of discharge ports for discharging ink supplied from the common liquid chamber, and when the cap covers the plurality of discharge ports. And a pressure pump for circulating ink between the common liquid chamber and an ink tank for storing ink supplied to the supply liquid chamber. And a pressure path and a valve for opening and closing the suction path are provided in a suction path connecting the cap and the suction pump, and suction by the suction pump and circulation by the pressure pump are provided. An ink jet recording apparatus characterized in that the switching is performed. 8. The ink jet recording apparatus according to claim 7, wherein the pressure chamber is provided between the valve and the suction pump. 9. The ink jet recording apparatus according to claim 7, wherein the valve is closed and the suction pump is operated at the time of suction recovery of the recording head provided with the discharge port to reduce the negative pressure of the pressure chamber. An ink jet recording apparatus wherein the suction pump is continuously operated to perform suction recovery when the valve is opened in that state. 10. The ink jet recording apparatus according to claim 7, wherein the valve is closed and the suction pump is operated at the time of suction recovery of the recording head provided with the discharge port to reduce the negative pressure of the pressure chamber. An ink jet recording apparatus, wherein the operation of the suction pump is stopped when the set pressure is increased and the valve is opened. 11. The ink jet recording apparatus according to claim 7, wherein after completion of the suction recovery by the suction pump,
An ink jet recording apparatus, wherein waste ink in the cap is discharged into a waste ink tank by the suction pump. 12. The ink jet recording apparatus according to claim 7, wherein the valve is closed and the suction pump is operated at the time of suction recovery of the recording head, thereby operating the negative pressure of the pressure chamber. Ink jetting, wherein the pressure is increased, the valve is opened in that state to recover the print head, and after the suction recovery of the print head is completed, the valve is closed again to reduce the negative pressure in the cap. Recording device. 13. The ink pressurizing and circulating method according to claim 7, wherein the valve is closed and the discharge port is capped when the circulation of the bubbles generated in the ink supply pipe and the common liquid chamber is recovered. An ink jet recording apparatus characterized in that the amount of waste ink at the time is suppressed. 14. The ink jet recording apparatus according to claim 7, wherein the valve is closed when the circulation of the air bubbles generated in the ink supply pipe and the common liquid chamber is recovered, and the discharge port is capped to thereby perform the ink suction circulation. An ink jet recording apparatus, wherein air taken in from the discharge port is minimized. 15. The ink jet recording apparatus according to claim 7, wherein a buffer for trapping bubbles is provided in a supply path of an ink supply pipe used for recovery of circulation of bubbles. An ink jet recording apparatus comprising: 16. A cap for covering a discharge port for discharging ink, and a suction pump for performing suction from the discharge port when the cap covers the discharge port, wherein: A suction path connecting the suction pump is provided with a pressure chamber and a valve for opening and closing the suction path, and discharges ink from the discharge port in response to a cleaning pulse during suction by the suction pump. An ink jet recording apparatus characterized by the above-mentioned. 17. The ink jet recording apparatus according to claim 16, wherein said pressure chamber is provided between said valve and said suction pump. 18. The ink jet recording apparatus according to claim 16, wherein the valve is closed and the suction pump is operated at the time of suction recovery of the recording head provided with the discharge port to reduce the negative pressure of the pressure chamber. The ink jet recording apparatus, wherein the suction pump is continuously operated to recover the suction when the valve is opened in that state. 19. The ink jet recording apparatus according to claim 16, wherein the valve is closed when the recording head provided with the discharge port recovers the suction, and the suction pump is operated to reduce the negative pressure of the pressure chamber. An ink jet recording apparatus, wherein the operation of the suction pump is stopped and the valve is opened when the pressure is increased to a set pressure. 20. The ink jet recording apparatus according to claim 16, wherein all the waste ink in the cap is discharged to a waste ink tank after completion of the suction recovery. 21. Any one of claims 16, 18, and 20
In the inkjet recording apparatus described in one, the valve is closed at the time of recovery of suction of the recording head, a negative pressure is increased by operating the suction pump, the valve is opened in that state, and the recording head is recovered, After completion of the recovery of the recording head, the valve is closed again to relieve the negative pressure in the cap, and the ink jet recording apparatus is characterized in that the valve is closed. 22. The inkjet recording apparatus according to claim 16, wherein the cleaning pulse is at least a pulse width, a pulse voltage, a pulse driving frequency, and a pulse timing with respect to a driving pulse for driving the recording head. An ink jet recording apparatus characterized in that one is different. 23. The ink jet recording apparatus according to claim 16, wherein the cleaning pulse starts the suction recovery operation in accordance with the timing of the suction recovery operation or the scale of the suction recovery operation. An ink jet recording apparatus, wherein a voltage is applied to a recording head from a predetermined time before a predetermined time after the end of the suction recovery operation. 24. The ink jet recording apparatus according to claim 16, wherein the cleaning pulse has a pulse width, a pulse voltage, and a pulse width corresponding to a driving pulse for driving the recording head. An ink jet recording apparatus, wherein at least one or a combination of drive frequencies is temporally changed for each ejection port, so that an interference wave due to ink is generated in the recording head. 25. The ink jet recording apparatus according to claim 16, wherein the cleaning pulse is supplied from the start of the suction recovery operation in accordance with the timing of the suction recovery operation or the scale of the suction recovery operation. An ink-jet recording apparatus wherein the voltage is applied to the recording head once or in a plurality of times until the end of the suction recovery operation. 26. A cap for covering a discharge port for discharging ink, and a suction pump for performing suction from the discharge port when the cap covers the discharge port. A suction path connecting the suction pump is provided with a pressure chamber, a valve for opening and closing the suction path, and a pressure sensor for detecting a pressure of waste ink in the suction path. Ink jet recording device. 27. The ink jet recording apparatus according to claim 26, wherein at the time of a suction recovery operation, a cleaning pulse is activated by an energy generating means of the recording head provided with the discharge port, thereby causing the recording head and the waste ink flow path to move. An ink jet recording apparatus further comprising a cleaning pulse generating means for removing air bubbles. 28. The method according to claim 26, wherein the recording head is brought to a position facing the cap, and wherein the recording head is located at a position facing the cap. After closing the discharge port surface of the recording head with the cap, closing the discharge port surface of the recording head with the cap, closing the valve, and starting the operation of the suction pump, The suction ink is sucked through the waste ink flow path. During the suction by the suction pump, the pressure sensor detects that the pressure in the waste ink flow path has reached a preset pressure equal to or lower than the pressure at which suction recovery is possible. And detecting that the pressure in the waste ink flow path has reached a preset pressure by the pressure sensor, and then opening the valve. Characteristic ejection recovery processing method. 29. The discharge recovery processing method according to claim 28, wherein after the valve is opened, the operation of the suction pump is stopped, and after the operation of the suction pump is stopped, the pressure in the waste ink flow path is reduced. After the pressure sensor detects that the pressure has reached the atmospheric pressure, the cap is opened from the recording head, and after the cap is opened from the recording head, the operation of the suction pump is started again and the waste ink is discharged. A discharge recovery processing method, comprising: suctioning waste ink remaining in the flow path, and stopping the operation of the suction pump. 30. The ejection recovery processing method according to claim 28, wherein after the valve is opened and before the pressure in the waste ink flow path reaches atmospheric pressure, the valve is closed again and the pressure of the suction pump is reduced. After stopping the operation, after stopping the operation of the suction pump, opening the cap from the recording head, opening the cap from the recording head, opening the valve again, and opening the valve again The operation of the suction pump is restarted to suck the waste ink remaining in the waste ink flow path, and the operation of the suction pump is stopped. 31. The discharge recovery processing method according to claim 28, wherein after the valve is opened, the operation of the suction pump is stopped, and after the operation of the suction pump is stopped, the valve is opened.
Then, after closing the valve again, after closing the valve again, opening the cap from the recording head, after opening the cap from the recording head, opening the valve again, after opening the valve again The operation of the suction pump is restarted to suck the waste ink remaining in the waste ink flow path, and the operation of the suction pump is stopped. 32. The ejection recovery processing method according to claim 28, wherein during the operation of the suction pump, a cleaning pulse is activated by the energy generating means of the recording head to remove bubbles in the recording head and the waste ink flow path. An ejection recovery processing method, characterized by removing. 33. An ink jet recording apparatus according to claim 1, wherein said recording means comprises an electrothermal converter for generating thermal energy used for discharging ink. An ink jet recording apparatus comprising an ink jet recording means provided. 34. The ink jet recording apparatus according to claim 33, wherein the ink is ejected from an ejection port by utilizing film boiling generated in the ink by thermal energy generated by the electrothermal transducer. apparatus.