JP3190540B2 - Inkjet printing equipment - Google Patents

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 apparatus and, more particularly, to an ink-jet printing apparatus for printing on a cloth or the like.

[0002]

2. Description of the Related Art As a typical method of printing on a cloth or wallpaper, a screen printing method of directly printing on a cloth or the like using a silk screen plate is known. In this method, first, a silk-screen plate is prepared for the original image to be printed for each color used in the original image, and the silk-screen plate is attached to a screen printing device, and is passed through a mesh of the silk-screen plate. Printing is performed by directly transferring the ink to a cloth or the like.

However, this screen printing method requires a great deal of man-hours and days to prepare a silk-screen plate in advance, and also requires operations such as preparation of ink of each color and alignment of the silk-screen plate for each color. There is a problem. Furthermore, the device itself is large,
In addition, there is a problem that the size becomes large in proportion to the number of colors to be used, an installation space is required, and a space for storing a silk-screen version is also required.

Therefore, an ink jet printing system has been proposed in which printing is performed directly on a printing medium such as a cloth or wallpaper. This inkjet printing method
This method discharges minute ink droplets from the discharge port of the inkjet head to form ink dots on the print medium such as fabric and prints images, etc., eliminating the need for the screen plate required for conventional screen printing. In addition, the process and the number of days required for forming an image on a cloth or the like can be greatly reduced, and the apparatus can be downsized. In addition, print information for printing can be stored on media such as tapes, flexible disks, and optical disks, so that the storage and preservation properties of print information are excellent, and the color scheme for the original image can be changed, the layout can be changed, enlarged, and reduced. For example, there is an advantage that print information can be easily processed.

On the other hand, fabrics used as printing media used in such ink jet printing include natural fibers such as cotton, silk and wool, synthetic fibers such as nylon, rayon and polyester, and blends of these fibers. Over. Therefore, in order to print satisfactorily on a fabric made of these fibers, it is desirable that the dye of the ink is also in accordance therewith. For example, it is desirable to use a coloring material that is insoluble or hardly soluble in water, such as a disperse dye for polyester fiber, a metal complex dye for wool, and a vat dye or pigment for cotton.

In order to produce an aqueous ink using a dye which is insoluble or hardly soluble in water, it is common practice to atomize the raw material of the dye, and disperse and emulsify it in water with a dispersant. However, when an aqueous ink in which such a dispersing material is dispersed and emulsified is used, the dye in the ink agglomerates and sediments with time, thereby causing a change in the print density due to a change in the density of the dye or a problem in the ink path. May cause clogging.

To solve such a problem, see, for example,
No. 57342 discloses a function of stirring ink,
It has been proposed to always perform this to prevent the dye in the ink from aggregating and settling.

[0008]

However, the configuration of the prior art proposed in the above publication alone may not be enough to make full use of the aqueous ink using the insoluble or hardly soluble dye described above.

For example, when the motor is continuously rotated for stirring at the time of using the ink jet printing apparatus main body, generation of bubbles in the ink and incorporation of dissolved oxygen cannot be avoided. Even if the stirring power is weakened, it is difficult to avoid the above-mentioned bubbles and the like, and in this case, these bubbles and dissolved oxygen grow to larger bubbles due to an increase in the head temperature and the like. In some cases, ejection failure such as non-ejection of ink may be caused by the generation of bubbles. The problem of the ejection failure due to the growth bubbles becomes more remarkable when a head of a method of generating ink using thermal energy and thereby discharging ink is used.

[0010] It has also been experimentally confirmed that if the stirring time is too long, the dispersibility of the dye is conversely reduced, thereby causing a change in print density. This is presumed to be due to the fact that the agitation for a long time increases the chances that the dye molecules collide with each other and accelerates the aggregation, and as a result, the precipitation of the dye is accelerated and the ink concentration becomes uneven. Also,
The accelerated agglomeration increases the average particle size of the dye, which causes clogging of the filter and the ejection openings in the ink path.

Furthermore, the configuration of the above-mentioned conventional example is not realistic from the viewpoint of the life of the stirring motor. That is, in the case of a printing machine, unlike a general office printer, 24 hours a day is required.
Continuous operation for a long period of time is also performed normally, and a long life of the apparatus main body as a production facility, for example, 5 years or more, is required. Accordingly, the life required for the stirring motor is extremely long when the operating time is used, and it is a reality that a motor that satisfies this condition cannot be easily found. On the other hand, as one measure to solve this problem, making the motor replaceable is considered, but this is not preferable in terms of the device configuration and cost.

Accordingly, it is an object of the present invention to provide an ink jet printer which can use inks using dyes which are hardly soluble or insoluble in water without causing problems regarding bubbles due to agitation even when continuous operation is performed for a long time. A printing device is provided.

[0013]

According to the present invention, there is provided:
Using an inkjet head that ejects ink, an inkjet printing apparatus that performs printing by ejecting ink containing a dye to a print target medium, an ink tank that supplies ink to the inkjet head,
Stirring means for stirring the ink in the ink tank, stirring control means for controlling the stirring operation by the stirring means,
A timer for measuring an elapsed time, wherein the stirring control means, when instructed to start printing, based on a time measured by the timer, a time elapsed from a previous stirring operation for a predetermined time. In the above case, the agitating operation is performed by the agitating means. During the printing operation, control is performed such that the agitating operation is performed every time the elapsed time from the previous agitating operation is equal to or longer than the predetermined time. The stirring time of the ink in the stirring operation is a time during which the dye in the ink does not agglomerate.

[0014] More preferably, the ink is an aqueous ink in which a dye insoluble or hardly soluble in water is dispersed.

[0015]

According to the above arrangement, the control of the stirring operation by the stirring means is performed when the printing start is instructed and the elapsed time from the previous stirring operation is equal to or longer than a predetermined time. During the printing operation, control is performed such that the stirring operation is performed every time the elapsed time from the previous stirring operation becomes equal to or longer than a predetermined time, and the time of stirring in one stirring operation is set in the ink. By setting the time during which the dye does not agglomerate, the print density does not fluctuate, and the clogging of the discharge port of the ink jet head is suppressed, and the ink using the dye which is hardly soluble or insoluble in water can be used. It becomes possible.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an ink jet printing apparatus according to one embodiment of the present invention.

In FIG. 1, a carriage 1 has print heads 2a, 2b, 2c and 2d for ejecting cyan, magenta, yellow and black inks, respectively, and two guide shafts 3 move the carriage 1. The guide is supported as possible. A part of the belt 4 in the form of an endless belt is connected to the carriage 1, and the driving force of a driving motor 5 as a pulse motor whose driving is controlled by a motor driver 23 is controlled via the belt 4. It is transmitted to the carriage 1. Thus, the carriage 1 can move on the guide shaft 3 along the print surface of a paper, an OHP film, a cloth, or another print medium (hereinafter referred to as print paper) 6. Further, a transport roller 7 for transporting the print paper 6,
The print paper 6 is transported by guide rollers 8A and 8B for guiding the print paper 6, a print paper transport motor 9, and the like.

Each of the print heads 2a, 2b, 2c and 2d is provided with a discharge port for discharging ink droplets and a liquid path (not shown) communicating therewith. Also,
To each print head, ink is supplied from the corresponding ink tanks 11a, 11b, 11c and 11d via supply tubes 12a, 12b, 12c and 12d. In the liquid path of each print head, an electrothermal conversion element for generating thermal energy used for discharging ink is provided, and these elements are more flexible than the respective head drivers 24a, 24b, 24c, 24d. An ink ejection signal is selectively supplied via the cables 13a, 13b, 13c, and 13d. Further, each of the print heads 2a, 2b, 2c and 2d is provided with a head heater and a temperature detection sensor, and the control circuit 16 controls the head heater via a driver 17 and a power supply 18 based on the temperature detection signal. To control the heating of

The capping unit 20 is in contact with the ejection opening surfaces of the print heads 2a, 2b, 2c and 2d during non-printing, and prevents thickening of ink in each print head during non-printing. It performs functions such as doing. That is, at the time of non-printing, the carriage 1 on which the print heads 2a, 2b, 2c and 2d are mounted.
Moves to a position facing the capping unit 20. Thereafter, the capping unit 20 is moved in the direction of each print head by the power of a motor (not shown) driven by the cap driver 25, and the unit 2 is moved.
The capping is performed by pressing the elastic member 44 provided on the front surface of the nozzle 0 against the discharge port surface. A liquid-absorbing material that can be kept wet with ink is provided inside the cap unit 20, so that the inside of the cap unit can be maintained at a high humidity and the viscosity of the ink can be minimized. .

FIG. 2 is a schematic diagram showing a detailed configuration of an ink supply path in the above-mentioned ink jet printing apparatus.

The main tank 11a (11b, 11c, 1)
In the ink supply path between 1d) and the print head 2a (2b, 2c, 2d), a sub-tank 105 (not shown in FIG. 1) is provided for stabilizing the ejection by keeping the head difference constant. . The ink in the main tank 11a is pump 1
04 is supplied to the sub tank 103. Each component of the ink supply system is connected by an ink supply tube 105. The supply of ink from the sub tank 103 to the head 2a is performed according to the ejection operation of the head 11a by a normal capillary action. Further, at the time of a head ejection recovery operation described later, ink is forcibly supplied to the print head 2a by using the sub tank pump 106.

In the above configuration, the sub tank 10
The ink supply to the pump 3 is controlled in accordance with a detection signal from an ink level sensor 107 provided in the sub tank.
04 is driven. Also, the main tank 1
1a is provided with a similar liquid level sensor 108. When the amount of ink in the main tank is reduced by this, a warning can be given to the user based on the detection output to urge the ink supply. The main tank 11a is provided with an ink stirring member 102, and a driving source 1 having a motor and the like.
10 is driven to rotate. Thereby, the ink stored in the main tank 11a is stirred, and aggregation and settling of the ink dye can be prevented. Ink stirring member 10
2 is made of a member having a length of 50 mm, a width of 20 mm, and a thickness of 10 mm. The driving of the ink stirring member 102 is controlled by the control circuit 16 (see FIG. 1). That is, it is intermittently driven at a predetermined timing as described later.

In addition to the main tank 11a, when the non-printing time is long, the above-mentioned aggregation of the ink dyes may occur. However, these may be prevented by the ink flow due to the ejection recovery operation. Can be discharged from the ejection opening of the head.

The ejection recovery operation is performed, for example, after leaving for a long time, at the start of printing, or during printing.
For example, when the apparatus is left in a non-printing state for a long time, the ink in the ejection ports is slow but evaporates and thickens even in the capping state. Also, microbubbles generated or mixed inside the discharge port may grow into larger bubbles. Therefore, when the apparatus is turned on after being left for a long time, or when printing is started, the pump 106 provided in the sub tank 103 is driven to pressurize the ink, and the thickened ink and the residual air bubbles inside the discharge port are discharged outside the discharge port. I do. Further, by performing the ejection recovery operation during the printing operation, even if dust or water droplets adhere to the ejection surface or dust or the like is mixed in the ejection port, the ejection can be washed out and stable ejection can be maintained.

Referring again to FIG. 1, the clogging prevention unit 31 includes the print heads 2a, 2b, 2c and 2c.
d receives the discharged ink when performing so-called preliminary discharge. That is, the clogging prevention unit 31 is provided with a liquid receiving member 32 as a liquid receiving portion that faces the print heads 2a, 2b, 2c, and 2d by moving the heads and absorbs ink discharged from each head. It is arranged between the capping unit 20 and the print start position of the carriage 1.

The cleaning unit 50 includes a cleaning electromagnetic valve 51.
And the suction pump and the driver 52 are connected to each other, and the driving thereof is controlled by the control circuit 16 to apply the cleaning liquid to the wiping blade and to suction the cleaning liquid.

FIGS. 3 and 4 show details of the cleaning unit 50. FIG. FIG. 3 is an explanatory diagram when the cleaning unit 50 is viewed from the main scanning direction of the head 2a.
FIG. 5 is an explanatory diagram when the blade 70 and the head 2a are viewed from above.

The blade 70 is formed of a flexible porous material. For example, the volume change due to absorption of ink mist is not remarkable unlike a polymer foam, and the blade 70 absorbs ink. It is preferable that the volume does not change. For example, a foamed formal resin type can be cited as a suitable one.

(Embodiment 1) FIGS. 5A and 5B show
6 is a flowchart illustrating a schematic sequence of a printing operation including a main tank stirring process according to the first embodiment of the present invention.

In FIG. 5A, when the power of the apparatus main body is turned on, this processing is started, and first, in step S501, the apparatus is initialized. This initialization is known, and includes, for example, initialization of the memory and start-up of the temperature control of the print head. Next, in step S502, the main tanks 11a, 11b, 11
The ink is stirred by rotating the ink stirring member 102 in c and 11d at a speed of 150 rpm for 5 minutes. Accordingly, it is possible to prevent sedimentation and aggregation of the ink dye that is occurring while the printing apparatus is left unattended.

After the above-described stirring process, in step S503, a stirring timer is set. That is, after performing the above-described stirring process at the time of electricity supply, the timer (T ₁ ) starts to perform the same stirring process at a predetermined time interval T ₀ .

When the above processing is completed, step S50
In step S4, a print operation is awaited, and when the start of printing is determined by transferring print data or the like, a print sequence from step S505 is performed. That is, step S5
In step S05, it is determined whether or not the time T ₁ counted by the timer has reached a predetermined time T _{0. If} the time T ₁ has not reached T ₀ , a print operation for one line is performed in step S506, that is, the carriage is moved. The associated ink ejection and conveyance of the print medium are performed. Further, it is determined in step S507 whether or not the printing has been completed. If it is determined that the printing has not been completed, the processes in and after step S505 are repeated. Here, T ₀ can be determined as a time that does not cause a problem of ink precipitation, and is substantially determined by the characteristics of the ink.

In step S505, the timer time T ₁ is counted.
Is longer than the predetermined time T ₀ , the main tank stirring process shown in FIG. 5B, which is executed in parallel with the subsequent process, is started. In this process, step S511
In, the same stirring process and step S502, resets the stirred timer at step S512, and terminates this processing procedure starts counting the time again T _1. Incidentally, the stirring time in step S511, can be shorter than in the case of agitation performed in step S502, anyway, this time, depending on the time T ₀ for setting a rotational speed or a predetermined time of the agitating member Can be determined.

In the above processing, the stirring is performed at the time of turning on the power and at predetermined time intervals thereafter. However, for example, the timing of stirring is determined according to the elapsed time from turning on the power, the downtime of the apparatus, and the like. Is also good.

FIG. 6 shows the main tanks 11a, 11b, 11
It is sectional drawing which shows the inside detail of c and 11d. As shown in this figure, the ink stirring member 1 in the main tank
02 is disposed below the ink level sensor 108, the ink stirring member 102 can rotate in the ink even when the ink level in the main tank is at the lowest level. Air bubbles and ink foaming can be suppressed as much as possible.

FIG. 7 is a diagram showing the average absorbance, which is one of the indexes of the ink density, when the stirring time at the time of turning on the power is changed in the apparatus of this embodiment.

The conditions for measuring the above average absorbance are as follows:
The surface of the ink in the menk tank was sampled with a syringe and diluted 1000 times (diluent: ethanol 75%,
The absorbance of a neutral phosphate pH standard solution (2.5%, water 22.5%) was measured. The measuring instrument is Hitachi U-3
It is a 200-type self-recording spectrophotometer. The state of the ink at the time of sampling is the state after stirring for two weeks and after stirring for each time (0, 2, 4, 6, 8, 120 minutes).

As is clear from FIG. 7, after 2 weeks, when stirring is not performed at all (0 minute) or conversely, it is relatively long (12 minutes).
(0 min) When the mixture is stirred, the ink does not reach the usable density range. That is, if the stirring time is 2 to 8 minutes including 5 minutes in the present embodiment, it is possible to maintain the ink in a usable state without performing continuous stirring during printing.

The components of the ink used in this embodiment are shown below.

-Nickel chloride 0.0003 parts-Zinc sulfate 0.0003 parts-Calcium chloride 0.002 parts-Ion exchange water 25 parts All of the above components are mixed, and the mixture is p-p with sodium hydroxide.
After adjusting to H7 to 9 and stirring for 1 hour, the mixture was filtered through a Fluoropore Filter FP-100 (trade name, manufactured by Sumitomo Electric Industries, Ltd.) to obtain inks a, b and c containing the following disperse dye liquids I to III. Was.

Preparation of Disperse Dye Solutions I to III 20 parts of β-naphthalenesulfonic acid formaldehyde condensate 55 parts of ion-exchanged water 10 parts of diethylene glycol The above components were mixed, and 15 parts of the following disperse dyes were newly added to the solution. (That is, three kinds of solutions were prepared), and after premixing for 30 minutes, dispersion treatment was performed under the following conditions.

Disperse dye C.I. I. Disperse Yellow 198 C.I. I. Disperse Red 88 C.I. I. Disperse Blue 60 Dispersing machine: Sand grinder (Igarashi Kikai) Grinding media: Zirconium beads 1mm diameter Filling rate of grinding media: 50% (by volume) Grinding time: 3 hours Further, Fluoropore filter FP-250 (Sumitomo Electric Industries, Ltd.) ) To remove coarse particles and disperse dye liquids I to
I got III.

Preparation of inks (a to c) 40 parts of the above disperse dye solution I, II or III 24 parts thiodiglycol 11 parts 11 parts diethylene glycol 0.0005 parts sodium metasilicate 0.001 part iron sulfate Other disperse dyes include C.I. I. Disperse Yellow 5, 24, 54, 64, 79, 82, 83,
93,99,100,119,122,124,12
6,160,184: 1,186,198,199,2
04, 211, 224 and 237; I. Disperse Orange 13, 29, 31: 1, 33, 49, 5
4, 55, 66, 73, 118, 119 and 163;
C. I. Disperse Red 54, 72, 73, 86,
88, 91, 92, 93, 111, 126, 127, 1
34,135,143,145,152,153,15
4,159,164,167: 1,177,181,2
04, 206, 207, 221, 239, 240, 25
8,277,278,283,288,311,32
3,343,348,356 and 362; I. Disperse Violet 33; I. Disperse Blue 56, 60, 73, 87, 113, 128, 14
3,148,154,158,165,165: 1,1
65: 2,176,183,185,197,198,
201, 214, 224, 225, 257, 266, 2
67,287,354,358,365 and 368;
C. I. Disperse Greens 6: 1 and 9 are preferred.

Further, these disperse dyes can be used alone or in combination of two or more kinds, and the content of these dyes (total content when two or more kinds are used in combination) is 0.1.
It is in the range of 5 to 25% by weight, preferably 1.0 to 20% by weight, more preferably 1.5 to 15% by weight. When the content of the disperse dye is less than 0.5% by weight, the color density is insufficient. If the content exceeds 25%, the storage stability of the ink is deteriorated, and the ink is not ejected due to thickening or precipitation accompanying the evaporation of the ink near the nozzle tip.

(Other Embodiments) FIGS. 8A to 8C are timing charts showing three examples of the driving mode of the ink stirring member.

FIG. 8A shows the driving mode described in the first embodiment, in which driving is performed continuously for 5 minutes.

FIG. 8B shows an example in which intermittent driving is performed at predetermined time intervals, instead of driving continuously for 5 minutes as described above. FIG. 8C shows an example in which intermittent driving is performed and the rotation direction of the stirring member 102 is alternately reversed.

The time interval of such intermittent driving is such that a constant flow occurs in the ink by stirring, and in this embodiment, it is about 10 seconds or more. According to such intermittent driving, it is possible to reduce the power energy and the stirring time.

FIG. 9 is a view showing another embodiment of the structure for stirring the main tank. That is, as shown in the figure, two main tanks 11a, 11b, 11c, and 11d are provided.
Two liquid level sensors 108a and 108b are provided to detect liquid levels in two stages. Accordingly, when the ink amount is relatively large until the liquid sensor 108b detects the predetermined liquid level, the rotation speed of the stirring member 102 is set to the relatively high rotation speed I. After that, the stirring member 102 is rotated at a rotation speed II lower than the rotation speed I until the liquid level sensor 108a detects a predetermined liquid level. According to such a configuration, uniform stirring can be realized regardless of the amount of ink in the main tank.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble 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 a liquid (ink) 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. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination configuration of the discharge port, the liquid path, and the electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 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. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

Further, it is preferable to add a recording head ejection recovery unit, a preliminary auxiliary unit, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

Regarding the type and number of recording heads to be mounted, for example, in addition to the recording head having only one corresponding to a single color ink, it corresponds to a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not limited to the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0060]

As is clear from the above description, according to the present invention, the control of the stirring operation by the stirring means is performed when the print start instruction is given, and the elapsed time from the previous stirring operation is longer than a predetermined time. When the printing operation is started, the stirring operation is performed, and during the printing operation, the stirring operation is performed every time the elapsed time from the previous stirring operation becomes equal to or longer than a predetermined time. In the operation, the stirring time can be set to a time during which no aggregation occurs in the dye in the ink.

As a result, the incorporation of bubbles into the ink due to the continuous stirring operation can be reduced, and the life of, for example, a motor serving as a driving source of the stirring operation does not need to be considered substantially. Further, reaggregation of the ink dye due to stirring for a long time can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an inkjet printing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an ink supply system in the apparatus shown in FIG.

FIG. 3 is a sectional view showing a detailed configuration of a cleaning unit in the apparatus shown in FIG.

FIG. 4 is a diagram showing a positional relationship between a blade of the cleaning unit and a print head.

FIGS. 5A and 5B are flowcharts showing a procedure of a main tank stirring process according to an embodiment of the present invention.

6 is a diagram showing a positional relationship of an ink stirring member in the ink tank shown in FIG.

FIG. 7 is a diagram showing the relationship between the ink stirring time of the main tank and the average absorbance of the ink in the apparatus according to one embodiment of the present invention.

FIGS. 8A, 8B, and 8C are timing charts each showing a driving mode of an ink stirring member to which the present invention is applied.

FIG. 9 is a diagram illustrating a configuration for stirring a main tank according to another embodiment of the present invention.

[Explanation of symbols]

 2a, 2b, 2c, 2d Print head 11a, 11b, 11c, 11d Main tank 50 Cleaning unit 70 Blade 102 Ink agitating member 103 Sub tank 104 Pump 105 Ink tube 106 Pressure motor 107 Sub tank level sensor 108, 108a, 108b Main tank Liquid level sensor 111 Main tank stirring member drive source

────────────────────────────────────────────────── ─── Continuation of the front page (72) Katsuhiro Watanabe, Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-5-229140 (JP, A) JP-A-55 -87568 (JP, A) JP-A-4-366646 (JP, A) JP-A-61-57342 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/175

Claims (9)

(57) [Claims] [Claim 1] using an ink jet head for ejecting ink, the ink-jet printing apparatus for printing out ejection <br/> ink for the target printing medium containing a dye, ink data supplying ink to said ink jet head
Includes a tank, a stirring means for stirring the ink in the ink tank, a stirring control means for controlling the stirring operation by said stirring means, a timer for measuring the elapsed time, and the agitation control means, a print start Was instructed
Based on the time measured by the timer,
If the time elapsed from the stirring operation of
Stirring operation by the stirrer is performed and during the printing operation.
Is the time elapsed since the previous stirring
And control to perform the stirring operation each time
Time for stirring the ink in one stirring operation
Is a time during which the aggregation of the dye in the ink does not occur . 2. The ink jet printing apparatus according to claim 1, wherein the ink is an aqueous ink in which a dye insoluble or hardly soluble in water is dispersed. Wherein said stirring control means, stirring movement of the ink by the stirring means when the power of the apparatus is <br/> turned
The inkjet printing apparatus according to claim 2 , wherein the operation is performed . 4. The stirring means is provided in the ink tank.
The ink is stirred by the rotating operation of the beam stirring member.
4. The method according to claim 1, wherein
5. The inkjet printing apparatus according to claim 1. 5. The ink in one stirring operation
The ink jet printing apparatus according to claim 4 , wherein the stirring is performed by intermittent rotation of the stirring member . 6. The ink in one stirring operation
Of the stirring member in the forward and reverse directions of the stirring member.
5. The method according to claim 4 , wherein the rotation is performed intermittently.
5. The inkjet printing apparatus according to claim 1. 7. A method for detecting a liquid level of ink in the ink tank.
The stirring control means further comprises a detecting means for detecting
A rotation speed of the stirring member according to a liquid level of the ink.
Ink-jet printing apparatus as claimed in claim 4, characterized in that to control. 8. The method according to claim 1, wherein in said one stirring operation,
The stirring time is from 2 minutes to 8 minutes.
Ink jet pudding according to any one of claims 1 to 7,
Device. Wherein said ink jet head is in any one of claims 1 to 8, characterized in that for ejecting ink based on utilizing the thermal energy generated in the bubble causes the bubble to the ink An inkjet printing apparatus as described in the above.