JPH11198396A - Ink jet printing method and apparatus - Google Patents

Abstract

(57) [Problem] To clean a discharge port surface of a head, a large amount of cleaning liquid needs to be used, and the entire discharge port surface cannot be reliably cleaned. An apparatus for forming an image on a print medium using a print head (16) having a discharge port for discharging a liquid, wherein the liquid discharge state from the discharge port of the print head (16) is adjusted appropriately. Recovery processing means, the recovery processing means comprising: a cleaning liquid foaming means for foaming a cleaning liquid 42 for cleaning an ejection port surface of the print head 16 having an ejection port opened; And a cleaning liquid supply means for supplying the cleaning liquid 42 to the discharge port surface 2 of the print head 16.
3 to perform cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing method and apparatus for discharging a liquid from a discharge port of a print head to perform printing on a print medium, and more particularly to a discharge port surface of a print head having a discharge port opening. Can be efficiently cleaned.

[0002]

2. Description of the Related Art In an ink jet printing apparatus in which a desired image is formed by discharging ink droplets on paper, cloth, resin, metal, or the like, a print head is not in contact with such a print medium. It has the advantages of excellent quietness, high printing speed, high-density printing, easy colorization, and downsizing of the entire apparatus.

[0003] In such an ink-jet printing apparatus, since the ink droplets are ejected from the ejection port of the print head, if the apparatus is not used for a long period of time, the ejection port, its vicinity, and the ejection port are connected. As the moisture in the ink adhered to the inner wall of the communicating ink path evaporates, the viscosity of the ink increases, or the ink adheres to the vicinity of the ejection port or the inner wall of the ink, and the ejection direction of the ink droplet is deflected. In addition, problems such as non-ejection where the ink droplet is not ejected from the ejection port occur.

In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 50-57518 proposes a technique for intermittently ejecting ink when printing is stopped, and Japanese Patent Publication No. 56-38991 discloses an ink supply system. There has been proposed a technique of stopping ink ejection for drying prevention in response to an alarm signal based on detection of ink leakage or the like in,
Further, Japanese Utility Model Application Laid-Open No. 52-42031 proposes a technique of adsorbing ink droplets ejected at the time of preliminary ink ejection prior to printing with an adsorption band.
Japanese Patent Application Publication No. 366 proposes a technique for performing test ejection in accordance with the degree of drying in order to prevent adverse effects due to drying of the ejection port, and to suppress the above-described problems such as the above-described deviation and non-ejection.

In Japanese Patent Application Laid-Open No. 54-9928,
When the ink runs out due to the drying of the ejection openings, the print head is moved to a predetermined position and a recovery operation is performed.
A technique for resuming the print signal after returning the print head to the original position where the ink shortage has occurred has been proposed. In Japanese Patent Application Laid-Open No. 54-48551, in order to prevent the adverse effect due to clogging of the ejection port, There has been proposed a technique for applying an injection driving force stronger than usual at the time of starting the apparatus.
Japanese Patent Application Laid-Open No. 5-82660 proposes a technique for ejecting ink droplets from all the ejection openings when the ejection suspension time of the ink droplets exceeds a predetermined time.

As described above, in the ink jet printing apparatus, the ink adhering to the discharge port and its vicinity and the ink in the ink path are dried by leaving the ink jet printing apparatus for a long period of time, and solid components are deposited. When the viscosity increase or sticking of the ink is slight, the wiping means for wiping the discharge port surface of the print head where the discharge port is opened, and the preliminary discharge means forcibly discharging the ink prior to the printing operation, It is possible to perform a recovery process to make the ejection state of the liquid from the print head appropriate, and if the ink is fixed a little more strongly than this, a suction unit that sucks the ink in the ink path from the ejection port is used. In some cases. But,
If the solidified ink is fixed very strongly,
It is difficult to make the ejection state of the liquid from the print head proper by the recovery process such as the normal wiping unit, the preliminary ejection unit, or the suction unit, and it is removed by dissolving the solidified ink using the ink or the cleaning liquid. There is a need to.

[0007] By the way, there is a case where an ink using a pigment is used due to a demand for water resistance and high density of an ink printed on a print medium. Such a pigment-based ink is more easily fixed than a normal dye-based ink using a dye, and has extremely poor recovery when fixed, and particularly generally includes a polymer as a so-called dispersant. Is known to have even worse recoverability.

On the other hand, in order to suppress the bleeding of the ink on the print medium and to improve the fixability, a processing liquid for adjusting the printability of the ink on the print medium is discharged onto the print medium separately from the ink, and the processing liquid is applied to the print medium. Techniques have been proposed in which ink penetration and bleeding between inks of different colors are suppressed.
These treatment liquids are useful in that they mix with the ink on the print medium and react with components in the ink to suppress inter-color bleeding and anisotropic penetration of the ink.

However, if the processing liquid permeates the print medium when the ink is discharged onto the print medium after the processing liquid is discharged onto the print medium, the effect of the processing liquid is reduced. In addition, it is necessary to discharge the ink to the print medium immediately after discharging the processing liquid. In this case, since the ink is overprinted on the processing liquid discharged to the print medium, the processing liquid rebounds to the discharge port surface of the print head due to the impact of ink landing, and may adhere to the discharge port surface. . Similarly, tiny mist-like processing droplets generated when the processing liquid is discharged may adhere to the discharge port surface of the print head that discharges the ink. In addition, when the processing liquid attached to the discharge port surface of the print head that discharges the processing liquid is removed by the wiping unit, the processing liquid may jump and adhere to the print head that discharges the ink.

The processing liquid adhering to the discharge port surface of the print head in this way reacts with the ink discharged from the print head and solidifies on the discharge port surface. The reaction products are often insoluble in water in view of the function of the processing solution, and are difficult to remove by general wiping means. For example, cleaning using a solution or cleaning by ultrasonic vibration Is required. Further, if these reaction products adhere to the vicinity of the ejection port for ejecting ink, the ink droplets ejected from the print head may be distorted or not ejected. Also, even when there is no direct effect on the ejection port, a part of the ejection port surface becomes hydrophobic, and the minute ink droplets that are generated secondarily during ink ejection and the ejected ink bounce on the print medium. Due to the fine ink mist generated by the ink, the ink adhering to the ejection port surface gathers in areas other than the hydrophobic part and becomes large particles, and the ink droplets ejected from the ejection port are likely to be distorted, reducing the print quality. Invite you.

[0011] The above-mentioned problem similarly occurs in a print head which discharges a processing liquid.

[0012]

The ink fixed to the print head is exposed to normal ink to redissolve it,
The processing liquid fixed to the print head that discharges the processing liquid is exposed to a normal processing liquid to redissolve it, or the reaction product of the ink fixed to the discharge port surface of the print head and the processing liquid is dissolved by the dissolving liquid. The cleaning method is an effective method for removing the adhered matter from the print head as compared with the wiping means, the preliminary discharge means, or the suction means. In particular, washing with a dissolving solution can be said to be extremely effective in terms of the reliability of removal of the adhered substance.

However, a large amount of cleaning liquid is required in order to reliably bring the cleaning liquid into contact with the discharge port surface when the adhered substance is dissolved, so that there is a lot of waste, and in particular, the discharge ports are arranged in a vertical direction. In the case of a print head having vertically arranged discharge ports, the method was very inefficient.

That is, as shown in FIGS. 10 and 11, which show the concept of a conventional cleaning method, a discharge port surface 2 in which discharge ports (not shown) of a print head 1 for discharging ink or a processing liquid are arranged in a vertical direction. When the cleaning liquid 3 is supplied from the cleaning liquid supply path 5 of the cleaning liquid supply means 4 to the cleaning liquid 3, the cleaning liquid 3 attached to the discharge port surface 2 flows down the discharge port surface 2 due to gravity. It is extremely difficult to supply the cleaning liquid 3 over the entire surface 2,
If the cleaning liquid 3 is forcibly supplied to the entire surface, a large amount of the cleaning liquid 3 is required.

As shown in FIG. 12, in the print head 1 in which the discharge port surface 2 faces vertically downward, a method of cleaning using a capping member 6 that covers the discharge port surface 2 of the print head 1 has been considered. I have. That is, the capping member 6 is filled with the cleaning liquid 3, and when the cleaning liquid 3 becomes full with respect to the capping member 6, the capping member 6 is pressed against the discharge port surface 2 of the print head 1, and By contacting the cleaning liquid 3, the discharge port surface 2 is cleaned. In this case, in order to cope with the so-called full-line type print head 1 in which the discharge ports are arranged over the entire width of the print area of the print medium, a capping member 6 having a large volume is required, and accordingly, the capping member 6 is required. The consumption of the cleaning liquid 3 also increases significantly.

In addition, the discharge port surface 2 and the capping member 6
Figure 1 shows that the upper end surface of the
As shown in FIG. 4, a part of the discharge port surface 2 does not come in contact with the cleaning liquid 3, and there is a possibility that a sufficient cleaning effect cannot be obtained. Similarly, if a sufficient amount of the cleaning liquid 3 cannot be supplied to the capping member 6, or if bubbles enter the capping member 6 for some reason, as shown in FIG. The portion of the discharge port surface 2 that is in contact cannot contact the cleaning liquid 3,
It is difficult to obtain a cleaning effect.

As described above, in the ink jet printing apparatus of the type in which cleaning is performed using the cleaning liquid 3, a large amount of the cleaning liquid 3 needs to be used, and the cleaning liquid 3 is surely brought into contact with the discharge port surface 2 of the print head 1. In some cases, it was difficult to obtain a sufficient cleaning effect.

[0018]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printing method and apparatus capable of efficiently cleaning the discharge port surface of a print head without using a large amount of cleaning liquid.

[0019]

According to a first aspect of the present invention, there is provided an ink jet printing method for performing printing on a print medium by discharging liquid from a discharge port formed in a print head. Performing a recovery process for adjusting a discharge state of the liquid from the discharge port to an appropriate state. In this step, the cleaning liquid in a foaming state is supplied to the discharge port surface of the print head in which the discharge port is opened, and Cleaning an outlet surface.

According to a second aspect of the present invention, there is provided an ink jet printing apparatus for performing printing on a print medium by using a print head having a discharge port for discharging a liquid, wherein the discharge of the print head is performed. A recovery processing means for optimizing a discharge state of the liquid from the outlet, wherein the recovery processing means is a cleaning liquid foaming means for foaming a cleaning liquid for cleaning a discharge port surface of the print head in which the discharge port is opened. And a cleaning liquid supply unit for supplying the cleaning liquid in a foamed state to the discharge port surface.

According to the present invention, the cleaning liquid is foamed by the cleaning liquid foaming means of the recovery processing means, and the foamed cleaning liquid is supplied to the discharge port surface of the print head by the cleaning liquid supply means. Then, the cleaning liquid in the foamed state dissolves and cleans a solid substance such as ink fixed to the discharge port surface of the print head, thereby properly recovering the liquid discharge state from the discharge port of the print head. In this case, since the cleaning liquid is in a foaming state, it is difficult for the cleaning liquid to flow to the discharge port surface, and the cleaning liquid is maintained at the supply position on the discharge port surface.

[0022]

In the ink jet printing method according to the first embodiment of the present invention, the liquid is an ink for printing on a print medium or a processing liquid for adjusting printability of the ink on the print medium. The cleaning liquid may be an ink, a processing liquid, or a solution thereof.

The apparent specific gravity of the foamed cleaning liquid is as follows:
It is desirably 0.1 g / cm ³ or less, the surface tension of the cleaning solution is preferably in the range of 20dyne / cm ~50dyne / cm.

Further, in the ink jet printing apparatus according to the second aspect of the present invention, the discharge ports of the print head may be arranged along a vertical direction, and the recovery processing means covers the discharge port surface. May further include a capping member, and the cleaning liquid supply means may be in communication with the capping member.

The cleaning liquid supply means may supply the cleaning liquid in the foamed state to an inner volume of the capping member or more. In this case, the capping member may
It is desirable to have a drain port for discharging the excessively supplied foaming cleaning liquid to the outside of the capping member.

[0026] The print head may have a discharge energy generating section for discharging liquid from the discharge port. In this case, the discharge energy generating section includes an electrothermal converter for generating thermal energy. It is desirable to have

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ink jet printing apparatus according to the present invention capable of realizing the ink jet printing method according to the present invention will be described in detail with reference to FIGS. 1 to 9, but the present invention is not limited to such an embodiment. Instead, they can be further combined or applied to technologies in other fields that include similar problems.

FIG. 1 shows the appearance of the ink jet apparatus according to the present embodiment, and FIG. 2 shows the appearance of the ink jet cartridge. That is, reference numeral 11 denotes a guide shaft for guiding the carriage 12 in the directions of arrows a and b in the figure, and 13 denotes a spiral groove formed on the feed screw shaft 14.
Scans along the guide shaft 11 in the directions of arrows a and b according to the forward and reverse rotation of the feed screw shaft 14. Then, printing is performed on the print area of the print paper P as a print medium by the inkjet head 16 of the inkjet cartridge 15 mounted on the carriage 12 while moving.

Reference numeral 17 denotes a carriage drive motor;
Indicates the driving force of the carriage driving motor 17 and the feed screw shaft 14
Is a sheet pressing plate for pressing the print paper P toward the platen 21. In addition, as the recovery processing means according to the present invention, in the present embodiment, the capping member 2 having the opening 22 and covering the discharge port surface 23 of the ink jet head 16 (see FIG. 2).
Cleaning / suction means 25 which is connected to the capping member 24 and supplies foaming cleaning liquid via the capping member 24 during the recovery operation while sucking ink from the ink jet head 16; A cleaning blade 26 used for, for example,
A cleaning member 26 for supporting the capping member 24;
Is moved in the direction facing the ink jet head 16 through the nozzle, and the discharge port surface 23 of the ink jet head 16 is wiped.

Reference numeral 29 denotes a lever for driving the cleaning / suction means 25 via the gear 30 and the cam 31. Clutch switching means and the lever 29, the gear 30 and the cam 31 which are not shown by the carriage drive motor 17 during the suction operation. The driving force is transmitted through a transmission means composed of Reference numerals 32 and 33 denote photocouplers for detecting the home position of the carriage 12, and the home position is detected by blocking the optical path of the protruding lever 34 provided on the carriage 12, and the forward / reverse rotation of the carriage drive motor 17 is performed. The direction is switched.

The cleaning / suction means 25 in this embodiment is
A foaming means (not shown) for foaming a cleaning liquid for re-dissolving the ink fixed on the discharge port surface 23 and the like; a cleaning liquid supply means (not shown) for supplying a foamed cleaning liquid from a cleaning liquid tank (not shown) to the capping member 24; A suction unit (not shown) for sucking the cleaning liquid and the like in the capping member 24 after the cleaning and for removing the thickened ink in the inkjet head 16 is provided.

In the present embodiment, a cleaning liquid having the following composition was used as a cleaning liquid for re-dissolving the ink fixed to the discharge port surface. However, the cleaning liquid is not limited to this. An appropriate ink may be selected according to the composition of the ink jet head 16. For example, an ink having the same composition as the ink ejected from the inkjet head 16 can be used as the cleaning liquid.

Sodium dodecyl diphenyl ether disulfonate 0.5% Monoethanolamine 1.0% Diethylene glycol dimethyl ether 10.0% Lithium hydroxide 1.0% Water 87.5% Capping performed by the recovery treatment means of the present invention The capping operation by the member 24, the cleaning operation by the cleaning blade 26, and the cleaning / suction recovery operation by the cleaning / suction unit 25 are performed by the action of the feed screw shaft 14 when the carriage 12 comes to the area on the home position side. Although it is configured to perform a desired process, any configuration may be used as long as the desired operation is performed at a known timing.

The ink jet cartridge 15 which is exchangeably mounted on the carriage 12 is mounted on the carriage 12 of the ink jet printing apparatus in a positioned state, and exchanges electric signals with the ink jet printing apparatus. I have. The inkjet cartridge 15 includes an inkjet head 16 and
A head holder 35 for holding the inkjet head 16, a pressing block 36 for pressing the inkjet head 16 against the head holder 35, an ink tank 37 for storing ink, and a lid member 38 for sealing the inside of the ink tank 37. The ink tank 37 occupying most of the volume of the ink-jet cartridge 15 has a main part, and an air communication port 39 for maintaining the inside of the ink tank 37 at atmospheric pressure is formed.

Numerous discharge ports 40 for discharging ink
The inkjet head 16 on which is formed is pressed and held by the head holder 35 by the pressing block 36. The ink is guided from the ink tank 37 into the inkjet head 16 through an ink supply passage (not shown).

The ink-jet cartridge 15 of this embodiment has an ink-jet head 16 and an ink tank 37 integrally formed. The ink-jet head 16 has a structure in which the ink tank 37 side is exchangeably connected. An inkjet cartridge may be used.

Discharge port surface 23 of ink jet head 16
When performing the cleaning operation shown in FIG. 3, a cleaning liquid foaming means and a cleaning liquid supply means (not shown) are used to illustrate the working concept of FIG.
As shown in (1), a foamed cleaning liquid 42 is supplied into the capping member 24 from the supply / discharge port 41 of the capping member 24, and the inside of the capping member 24 is filled with the foamed cleaning liquid 42. In this state, the capping member 24 is moved to the discharge port face 2
3, the cleaning liquid 42 in a foamed state is attached to the discharge port surface 23, and the fixed ink on the discharge port surface 23 is redissolved. Thereafter, the foamed cleaning liquid 42 in the capping member 24 is sucked and discharged from the supply / discharge port 41 together with the re-dissolved ink using suction means (not shown), and the thickened ink in the ink path (not shown) of the inkjet head 16 is further discharged. Suction and discharge at the same time. Further, by wiping the discharge port surface 23 using the cleaning blade 26, the thickened ink, the fixed ink, and the like can be reliably removed from the inkjet head 16.

As described above, in order to prevent the cleaning liquid 42 in the foamed state from flowing out of the capping member 24, the apparent specific gravity of the cleaning liquid 42 in the foamed state is desirably 0.1 g / cm ³ or less. Similarly, the surface tension of the cleaning solution is 2
It is effective to be within the range of 0 dyne / cm to 50 dyne / cm.

The cleaning effect was confirmed as follows using such an ink jet printing apparatus. That is, first, the ink dried in an atmosphere of 60 ° C. for 3 days is applied to the ejection port surface 23 of the ink jet head 16 in which 64 ejection ports 40 are vertically arranged, and the cleaning liquid is mounted on the carriage 12. The number of ejection ports 40 from which ink was not ejected was measured as compared with the case where ink was not foamed.

The results are shown in Table 1. The numerical values before and after cleaning are as follows.
Compatible with all discharge ports.

[0041]

[Table 1]

As is clear from Table 1, when the cleaning liquid is supplied as it is without foaming, by supplying the cleaning liquid 42 in a foaming state, non-discharge of ink from a specific discharge port is completely eliminated. It turns out that not only can it be done, but in particular it can also completely eliminate the warpage.

When the cleaning liquid is supplied without foaming, the ink meniscus formed near the discharge port 40 is broken, and the cleaning liquid adhering to the discharge port surface 23 due to the negative pressure from the ink tank 37 is removed. A phenomenon of being sucked into the ink jet head 16 and mixing with the ink in the ink jet head 16 is observed.

When such a backflow phenomenon occurs,
Since the print quality thereafter deteriorates, it is necessary to discharge a considerable amount of ink from the ink jet head 16 in advance, which causes a disadvantage that the ink is unnecessarily consumed. In order to enhance the cleaning effect, it is desirable to use an alkali (for example, lithium acetate or sodium hydroxide) or a strong solvent (for example, NMP or diglyme) in which the dye contained in the ink is easily dissolved. In some cases, there is a concern that the above-described backflow phenomenon may adversely affect members constituting the inkjet head 16, particularly, sealants and adhesives. In addition, when the backflow phenomenon extends for a long time, the cleaning liquid may enter the ink tank 37 and become unusable.

In the ink jet printing apparatus of this embodiment, since the cleaning liquid in contact with the ink meniscus is in a foamed state, the probability that the ink meniscus is destroyed is low. Even if this ink meniscus is destroyed, unlike the case where a liquid cleaning liquid is used, when air bubbles come into contact with the ejection port where the ink meniscus has been destroyed, the ink meniscus is generated again, so that the backflow phenomenon is unlikely to occur. . In addition, since the supply amount of the cleaning liquid is small, even if a backflow occurs, it can be minimized.

In the above embodiment, the capping member 2
The cleaning liquid 42 in a foamed state is supplied into the inside of the nozzle 4.
A cleaning liquid foaming means and a cleaning liquid supply means which are independent of the capping member 24 and the suction means may be provided.

As shown in FIGS. 4 and 5 showing the procedure of the cleaning operation according to another embodiment of the present invention, the cleaning liquid 42 in a foamed state is supplied from the cleaning liquid supply passage 43 to the discharge port surface 23 of the ink jet head 16. The ink is ejected toward the discharge port (see FIG. 4), adheres and accumulates on the ejection port surface 23 to re-dissolve the fixed ink, and the ink is wiped off by the cleaning blade 26 or is suctioned and discharged by the suction means using the capping member 24. In this case, since the cleaning liquid 42 discharged to the discharge port surface 23 is in a foaming state, the cleaning liquid 42 in a foaming state is held over the entire surface of the discharge port surface 23, and the entire surface of the discharge port surface 23 is maintained. Can be washed.

In the above-described embodiment, the embodiment in which the discharge port surface 23 is disposed vertically has been described. However, the ink jet or ink jet processing liquid has a structure in which the discharge port surface 23 is disposed horizontally and the ink or processing liquid is discharged vertically downward from the discharge port. The present invention can be applied to a printing apparatus.

FIG. 6 shows the disassembled structure of the main part in another embodiment of the present invention, and FIGS. 7 and 8 show the outline of the cleaning operation. In other words, the six types of ink jet heads 44 to 49 capable of supporting color printing are 2
The head unit 50 is divided into a set of head units 50 and 51, and one of the head units 50 incorporates three inkjet heads 44 to 46 for ejecting a dark black ink, a processing liquid, and a light black ink, and the other head unit. Unit 51
Have three ink jet heads 47 to 49 for ejecting cyan ink, magenta ink and yellow ink.
Is incorporated. These inkjet heads 44
There are six types of ink tanks 52 to 57 containing dark black ink, processing liquid, light black ink, cyan ink, magenta ink, and yellow ink, respectively. Each of the ink tanks 52 to 57 is independently exchangeable depending on the degree of ink consumption.

When a printing operation is performed on a print medium (not shown), in this embodiment, the processing liquid is ejected from the processing liquid inkjet head 45 prior to discharging the color inks, ie, the cyan ink, the magenta ink, and the yellow ink. Is discharged onto a print medium. In the case of discharging the dark black ink and the light black ink, the dark black ink is discharged from the inkjet head 44, and then the processing liquid is discharged from the processing liquid inkjet head 45 onto the print medium. Ink is ejected from the inkjet head 46.

On the other hand, a pair of capping members 58 (only one of which is shown in FIGS. 7 and 8) which are arranged directly below the head units 50 and 51 and which can be moved up and down in the vertical direction are ink jets constituting the head units 50 and 51, respectively. The entire discharge port surface 59 of the heads 44 to 49 can be covered in a sealed state.
Are formed with cleaning liquid supply passages 61 communicating with cleaning liquid supply means (not shown). The cleaning liquid 42 foamed by the cleaning liquid foaming means (not shown) is supplied from these cleaning liquid supply passages 61 into the capping member 60 as shown in FIG.
It is pressed against the discharge port surfaces 59 of 0 and 51. As a result, the cleaning liquid 42 in a foamed state is applied to each inkjet head 4.
4 to 49, and the discharge port surfaces 59
The solid matter adhered to 9 is dissolved. In this case, since the opening of the capping member 60 faces upward, the foamed cleaning liquid 42 can be supplied until immediately before overflowing from the capping member 48, whereby the head units 50, 5 surrounded by the capping member 48 can be supplied.
The cleaning liquid 42 in the foamed state can be reliably brought into contact with the entirety of the one discharge port surface 59.

As described above, in the ink jet printing apparatus using both the ink and the cleaning liquid, the rebound of the ink or the processing liquid from the print medium surface causes
The reaction product obtained by mixing these is discharged face 5
However, as in the present embodiment, this can be reliably dissolved and removed by washing it with the washing liquid 42 in a foamed state, and a higher recovery effect can be obtained than when the liquid is supplied without foaming. be able to.

In order to more surely bring the foamed cleaning liquid 42 into contact with the discharge port surface 59, the capping member 48 is used.
Alternatively, an excessive amount of the cleaning liquid 42 in a foamed state may be supplied to the outside of the capping member 48.

FIG. 9 shows the structure of a main part of another embodiment of the present invention. Elements having the same functions as those of the previous embodiment are denoted by the same reference numerals, and will not be described. Shall be omitted. That is, the capping member 48 is formed with the drainage port 62, and the foamed cleaning liquid 42 supplied to the capping member 60 from the cleaning liquid supply passage 61 is filled in the capping member 60. When the part overflows, the cleaning liquid 4 in a foamed state is formed.
2 surely contacts the discharge port face 59 and, by flowing this, dissolution of the solid matter fixed to the discharge port face 59 is promoted.

It should be noted that the present invention has a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for discharging a liquid, particularly in an ink jet system. This provides an excellent effect in an ink jet printing apparatus of a type in which a change in the state of a liquid is caused by thermal energy. According to such a method, it is possible to achieve higher density and higher definition of the print.

The typical configuration and principle are described in, for example, US Pat. No. 4,723,129 and US Pat.
It is preferable to use the basic principle disclosed in Japanese Patent Application No. 0796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the flow path holding the liquid. Applying at least one drive signal to the electrothermal transducer that provides a rapid temperature rise exceeding nucleate boiling corresponding to the print information, thereby generating thermal energy in the electrothermal transducer and providing a thermal effect to the inkjet head. This is effective because film boiling occurs on the surface, and consequently, bubbles in the liquid corresponding to this drive signal can be formed one-to-one. By the growth and shrinkage of the bubble, the liquid is discharged through the discharge port to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. In addition,
US Patent No. 4 of the invention relating to the rate of temperature rise of the heat acting surface
By employing the conditions described in the specification of Japanese Patent No. 313124, more excellent printing can be performed.

The structure of the ink jet head is a combination of a discharge port, a flow path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned specifications. In addition, the present invention includes a configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting portion is arranged in a bent region. In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. JP-A-59-138461 which discloses a configuration corresponding to a discharge section
The effects of the present invention are effective even if the configuration is based on the above publication. That is, according to the present invention, printing can be performed reliably and efficiently regardless of the form of the inkjet head.

Further, the present invention can be effectively applied to an ink jet printing apparatus equipped with a full line type ink jet head having a length corresponding to the maximum width of a print medium that can be printed by the ink jet printing apparatus. Such an ink-jet head may have a configuration that satisfies its length by a combination of a plurality of ink-jet heads, or a configuration as one integrally formed ink-jet head.

In addition, even in the case of the serial type as described above, the ink jet head fixed to the apparatus main body,
Alternatively, a replaceable chip-type inkjet head that can be electrically connected to the apparatus main body or supplied with liquid from the apparatus main body when attached to the apparatus main body, or a tank that stores liquid integrally with the inkjet head itself The present invention is also effective when an ink jet cartridge provided with is provided.

Further, it is preferable to add preliminary auxiliary means for the ink jet head as a constitution of the ink jet printing apparatus of the present invention since the effect of the present invention can be further stabilized. Specific examples thereof include an electrothermal transducer of an ink-jet head, a preliminary heating unit for performing heating using a heating element different from this or a combination thereof, and a preliminary ejection unit for performing ejection other than printing. be able to.

Further, in the embodiment of the present invention described above, a material which solidifies at room temperature or lower and softens or liquefies at room temperature may be used, or in the case of an ink jet system, the liquid itself is 30 ° C. to 70 ° C. In general, the temperature is adjusted within the range described above to control the temperature so that the viscosity of the liquid is in the stable ejection range. Therefore, a liquid that is in a liquid state when the used print signal is applied may be used. In addition, in order to positively prevent the temperature rise due to thermal energy by using it as the energy of the state change from the solid state to the liquid state, or to prevent the liquid from evaporating, it is solidified in a standing state and liquefied by heating May be used.
In any case, the liquid is liquefied by the application of the thermal energy according to the print signal, and is liquefied only by the application of the thermal energy, such as the one from which the liquid is ejected and the one which already starts to solidify when reaching the print medium. The present invention can be applied to the case of using a material having a property. The liquid in such a case is, as described in JP-A-54-56847 or JP-A-60-71260, in a state where it is held as a liquid or solid substance in the concave portion or through hole of the porous sheet. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned liquids is to execute the above-mentioned film boiling method.

The form of the ink jet printing apparatus according to the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also a copying apparatus combined with a reader or the like, and a facsimile apparatus or a textile printing apparatus having a transmitting / receiving function. And the like.

[0063]

According to the present invention, by supplying the cleaning liquid to the discharge port surface of the head in a foamed state, it is possible to suppress the flow of the cleaning liquid due to the influence of gravity, and as a result, the cleaning liquid is supplied to the entire surface of the discharge port surface. Thus, it is possible to obtain a highly reliable ink jet printing apparatus by reliably preventing the liquid drop from being distorted or non-discharging.

Further, since the cleaning liquid is in a foaming state, consumption of the cleaning liquid can be greatly suppressed, and an economical ink jet printing apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the appearance of an embodiment of an inkjet printing apparatus according to the present invention.

FIG. 2 is a perspective view illustrating an appearance of an inkjet cartridge mounted on the inkjet printing apparatus illustrated in FIG.

FIG. 3 is a conceptual work diagram illustrating a concept of a method of cleaning a discharge port surface according to the present invention.

FIG. 4 is a work conceptual diagram showing the concept of another cleaning method of the discharge port surface according to the present invention together with FIG. 5, and shows a discharge state of a cleaning liquid.

5 is a work conceptual diagram showing the concept of another cleaning method of the discharge port surface according to the present invention together with FIG. 4, and shows a state in which the cleaning liquid is supplied to the discharge port surface.

FIG. 6 is an exploded perspective view illustrating a main part of another embodiment of the inkjet printing apparatus according to the present invention.

FIG. 7 is a conceptual work diagram illustrating a concept of a method of cleaning a discharge port surface in the embodiment illustrated in FIG. 6 together with FIG. 8;

FIG. 8 is a conceptual work diagram illustrating a concept of a method of cleaning a discharge port surface in the embodiment illustrated in FIG. 6 together with FIG. 7;

FIG. 9 is a conceptual work diagram illustrating a concept of another cleaning method for a discharge port surface.

FIG. 10 is an operation conceptual diagram showing a concept of a conventional cleaning method in the case of cleaning a discharge port surface using a cleaning liquid together with FIG. 11, and shows a discharge state of the cleaning liquid.

FIG. 11 is a work conceptual diagram showing the concept of a conventional cleaning method in the case of cleaning a discharge port surface using a cleaning liquid together with FIG. 10, and shows a state in which the cleaning liquid is supplied to the discharge port surface.

FIG. 12 is a work conceptual diagram showing a concept of another conventional cleaning method for a discharge port surface.

FIG. 13 is a conceptual work diagram showing a state in which a discharge port surface is inclined in the conventional cleaning method shown in FIG.

FIG. 14 is a conceptual work diagram showing a state in which bubbles are mixed in the cleaning liquid in the conventional cleaning method shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Guide shaft, 12 Carriage 13 Spiral groove 14 Feed screw shaft 15 Inkjet cartridge 16 Inkjet head 17 Carriage drive motor 18, 19 Gear 20 Sheet press plate 21 Platen 22 Opening 23 Discharge port surface 24 Capping member 25 Cleaning / suction means 26 Cleaning Blade 27 Support member 28 Support member 29 Lever 30 Gear 31 Cam 32, 33 Photocoupler 34 Projection lever 35 Head holder 36 Press block 37 Ink tank 38 Cover member 39 Atmospheric communication port 40 Discharge port 41 Supply / discharge port 42 Cleaning liquid 43 Cleaning liquid supply passage 44 to 49 Inkjet head 50, 51 Head unit 52 to 57 Ink tank 58 Connecting tube 59 Discharge port surface 60 Capping member 61 Cleaning liquid supply passage 62 Drain port P print Paper

Claims (12)

[Claims] 1. An ink jet printing method for performing printing on a print medium by discharging a liquid from a discharge port formed in a print head, the method comprising: setting an appropriate discharge state of the liquid from the discharge port of the print head. Supplying a cleaning liquid in a foamed state to the discharge port surface of the print head in which the discharge ports are opened, and cleaning the discharge port surface. Inkjet printing method. 2. The ink-jet printing method according to claim 1, wherein the liquid is an ink for printing on a print medium or a processing liquid for adjusting printability of the ink on the print medium. 3. The cleaning liquid according to claim 1, wherein the cleaning liquid is an ink, a processing liquid, or a solution thereof.
Or the inkjet printing method according to claim 2. 4. The ink-jet printing method according to claim 1, wherein the apparent specific gravity of the cleaning liquid in the foamed state is 0.1 g / cm ³ or less. 5. The cleaning liquid has a surface tension of 20 dyne / cm.
The ink jet printing method according to any one of claims 1 to 4, wherein the value is in the range of ~ 50 dyne / cm. 6. An ink jet printing apparatus for performing printing on a print medium using a print head having an ejection port for ejecting a liquid, wherein an ejection state of the liquid from the ejection port of the print head is adjusted. The recovery processing means comprises: a cleaning liquid foaming means for foaming a cleaning liquid for cleaning a discharge port surface of the print head in which the discharge port is opened; and An ink jet printing apparatus comprising: a cleaning liquid supply unit for supplying a cleaning liquid to a discharge port surface. 7. The ink jet printing apparatus according to claim 6, wherein the discharge ports of the print head are arranged in a vertical direction. 8. The apparatus according to claim 6, wherein the recovery processing means further includes a capping member for covering the discharge port surface, and the cleaning liquid supply means communicates with the capping member. Item 8. An inkjet printing apparatus according to item 7. 9. The ink jet printing apparatus according to claim 6, wherein the cleaning liquid supply unit supplies the cleaning liquid in a foamed state to an inner volume of the capping member or more. 10. The ink-jet printing apparatus according to claim 9, wherein the capping member has a drain port for discharging the excessively supplied foaming cleaning liquid to the outside of the capping member. . 11. The ink jet printing apparatus according to claim 6, wherein the print head has a discharge energy generating unit for discharging a liquid from the discharge port. 12. The ink jet printing apparatus according to claim 11, wherein the discharge energy generating section has an electrothermal converter for generating thermal energy.