JPH08276575A - Printer - Google Patents

Abstract

PURPOSE: To well control the temp. of the head of an industrial ink jet printer using a head having a relatively large number of ink emitting orifices. CONSTITUTION: A water jacket 7 is provided to the rear surface of the base plate 6 of an ink jet head 113 (113') and cooling water is passed through the water jacket 7. A temp. sensor 11 is provided to the rear surface of the base plate 6 and a flow rate controller 12 changes the driving of a pump 10 on the basis of the change of the output of the temp. sensor 11 corresponding to the temp. change of an ink passage 2 to change the flow rate of the cooling water 8 flowing through the water jacket 7. By this constitution, the excessive temp. rise of the head 113 (113') is suppressed and the temp. of the head can be always controlled to a definite range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device,
More specifically, it relates to a configuration for adjusting the temperature of the print head.

[0002]

2. Description of the Related Art Among various printing methods, for example, an ink jet printing method is widely used because it is used in a relatively small print output device. In such an inkjet printing apparatus, generally, the temperature of the print head changes depending on the history of printing operation and the ejection duty, and the print density may fluctuate or density unevenness may occur accordingly. Further, when the temperature of the print head rises sharply, ink ejection failure or ejection failure may occur. Furthermore, in the color printing device,
Due to the change in the head temperature, the temperature of each head may vary, and the hue of the printed image may change. The deterioration of the print quality due to the temperature change of the print head is not limited to the ink jet method as described above, and even if there is a difference in the degree, the printing apparatus of other methods such as a thermal transfer method has a better performance than before. This is a known issue.

In order to solve such a problem, for example, in an ink jet type printing apparatus, the following various countermeasures are taken within the range of the printing apparatus having a relatively small number of ejection openings of a head and a relatively slow printing speed. Proposed.

1) The temperature of the print head is detected and the printing speed, for example, the ejection frequency is controlled according to the detected temperature to adjust the temperature of the print head to suppress an excessive temperature rise (USP 4,910,528). 2) When the temperature of the print head becomes equal to or higher than a predetermined value, the printing operation is interrupted, and the printing operation is restarted after waiting for the temperature decrease (Japanese Patent Publication No. 3-4394).

3) The ejection duty is obtained in advance, and the print speed is controlled so that the temperature of the print head is constant (Japanese Patent Publication Nos. 61-17670 and 62-4).
No. 1114).

4) In accordance with the print data, a signal for generating sufficient thermal energy for ink ejection is given to the heater of the ejection port that ejects ink, and the heater of the ejection port that does not eject ink is A signal is generated to generate heat to the extent that does not result in ejection of ink, and as a result, the amount of heat generated by the print head is made constant, and the head temperature is made constant by balancing with natural cooling (Japanese Patent Laid-Open No. 1-22).
7361, JP-A-3-43254, JP-A-4-47948).

5) Cool the print head by circulating the ink in the print head (USP
4,929,963).

6) Cooling water is passed through the print head for forced cooling (EP 0,573,062). However,
The print head applied in this case is of the thermal transfer type.

[0009]

However, each of the solutions proposed above has the following problems.

In the configurations shown in 1) to 3) above, the means for lowering the head temperature is basically only natural heat radiation, and the time or amount of heat radiation is controlled by the time when the head is not driven. Therefore, when the ejection duty is high, the print speed decreases as a whole.
The controlled head temperature range is relatively wide, and the print density changes correspondingly wide.

For example, when such a technique is applied to an industrial ink-jet printing machine, an ink-jet printing machine, or the like, such an apparatus generally has a large number of head ejection ports and a high ejection duty. The amount of heat generated is large, the temperature is easily raised, and the print speed is lowered due to cooling of the print head, or the print operation is frequently interrupted. Further, in that case, even if the print speed is reduced, the effect of the reduction does not appear so much due to the large number of ejection ports, and the temperature rise of the print head may be unavoidable. After all,
With such a device, it is difficult to perform a printing operation continuously and at a certain speed or more. In addition, since the temperature changes greatly during the printing operation, the above-mentioned changes in the print density become more remarkable.

In addition, in the configuration described in 4) above, in addition to the heater that ejects ink, energy for heating is applied to the heater of the ejection port that does not eject ink, and the amount of heat generated by the print head is constant. On the other hand, the natural heat radiation is made constant, and the amount of heat generated by the print head is balanced with that of the natural heat radiation to make the temperature of the print head constant.

However, with such a structure, the total heat generation amount of the print head becomes enormous, and the temperature rise becomes more intense than in the examples 1) to 3), and continuous printing becomes more difficult. In order to enable continuous printing with this configuration, for example, it is necessary that the number of ejection ports is small, the printing speed is not so fast, and furthermore, the heat generated by the print head is small enough to be in time by natural heat dissipation. ,
Even in such a case, due to the temperature rise inside the machine accompanying the printing operation, the balance point with natural heat dissipation fluctuates,
Along with this, the print density changes gently. Further, the balance point of the head temperature also moves due to changes in temperature.

Further, the above method 5) cools the print head by circulating ink between the print head and the ink tank. However, since there is no mechanism for adjusting the temperature of the ink itself, if the printing operation is continuously performed for a long time, the temperature of the circulating ink gradually rises, causing a gradual change in the print density. . Furthermore, as a problem before that, when applying this technology to the cooling of a printhead with a large number of ejection ports and a high ejection duty, that is, a printhead with a large amount of heat generation, a sufficient amount of ink is circulated for cooling. Therefore, the pressure applied to the ink for that purpose becomes relatively large. Therefore, the meniscus of the ink formed in the vicinity of each ejection port in the head may be broken, and the ink may leak from the ejection port or air may be mixed. In such a case, the print function itself will be impaired.

As described above, the configurations shown in 1) to 5) are all small in size so that the number of ejection ports is small and the ejection duty is low, that is, the head can be adjusted only by natural heat radiation. Therefore, although it can be used for office printing devices that do not cause print density fluctuations and density unevenness to a great extent, there are strict requirements for print density fluctuations and density unevenness, and printing with high discharge duty is often used. It is not suitable for industrial printing devices.

Further, the configuration shown in 6) above is for cooling the print head specified by the thermal transfer system with cooling water, and is not considered for application to various types of printing devices for industrial use. .

As described above, even if any of the above-mentioned conventional configurations is adopted, there is no change in print density or density unevenness, print color reproducibility is good, and the print head can be driven with a high ejection duty. It has been difficult to realize an industrial inkjet printing device.

By the way, the recent ink jet printing technology has a wide range by the image processing technology such as the error diffusion method and the gradation expression ability by combining it with the multi-valued printing technology, and the conventional 6 to 10 color printing of four or more primary colors. In the image representation capability of inkjet printing technology in the color reproduction range, the technology level approaching that of offset printing is being reached.

On the other hand, the wide width by the serial printing method,
It is also possible to print a long large screen, and it is expected to be applied to industrial fields such as inkjet printing, large screen printing, and manufacturing of color filters for displays in combination with the gradation expression capability. However, the above-mentioned problem becomes a bottleneck, and there are various other advantages such as responsiveness as an output in computer publishing, a plate making process not required, and ink preparation not required, but the application to the above industrial fields. Is not progressing.

An object of the present invention is to realize uniform print density and accurate reproduction of color tone by accurately controlling the temperature of print heads of various printing systems. In particular, since the number of ejection openings is large and the ejection duty is large. An object of the present invention is to provide a printing apparatus suitable for use in a high industrial inkjet printing machine, an inkjet printing machine, or the like.

[0021]

Therefore, according to the present invention,
In a printing apparatus that uses a print head and prints on a print medium by the print head, cooling means for circulating a liquid to cool the print head, and head temperature detection means for obtaining information about the temperature of the print head And flow rate control means for changing the flow rate of the liquid by the cooling means based on the head temperature information obtained by the head temperature detection means.

Further, in a printing apparatus which uses a print head having a plurality of print elements and prints on a print medium by the print head having the plurality of print elements, a liquid is circulated to cause the plurality of print elements to flow. Cooling means for cooling the print head, a head temperature distribution detecting means for obtaining information about the temperature of the print head and its distribution corresponding to the positions of the plurality of print elements, and the print obtained by the temperature distribution detecting means. Cooling liquid control means for controlling the flow rate and direction of the liquid by the cooling means on the basis of the information on the temperature of the head and its distribution.

[0023]

According to the above construction, the flow rate of the cooling water can be changed according to the temperature change of the print head. Therefore, when the head temperature rises excessively, the flow rate of the cooling water is increased to increase the flow rate from the head. It is possible to accelerate the heat dissipation of the print head and consequently control the temperature of the print head within a certain range.

Further, since the flow rate and direction of the cooling water can be controlled in accordance with the temperature distribution of the print head, the temperature of the print head can be controlled within a certain range and the variation range of the temperature distribution of the print head can be controlled. It can be small.

[0025]

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

(First Embodiment) This embodiment shows an example in which the present invention is applied to an ink jet type textile printing machine, and FIG. 1 is a side view showing a schematic structure of the ink jet textile printing apparatus.

The construction of the apparatus of this example is roughly divided into a cloth feeding section B for sending out a roll-shaped cloth 103 which has been subjected to a pretreatment for printing, and an ink jet while precisely feeding the cloth 103 sent in stepwise. It is composed of a main body A for ejecting ink from the heads 113 and 113 'for printing, and a placing part C for cutting and placing the printed cloth 103. The main body part A further includes a cloth 10 including platens 112 and 112 '.
3 is composed of a precision feeding section A-1 and a print unit A-2.

The cloth 103 fed stepwise from the cloth supply section B to the main body section A is
Ink is ejected from an inkjet head 113 that scans in a direction perpendicular to the paper surface of FIG.
Print lines. Then, every time one line of printing is finished, the cloth 103 is fed by a certain amount in steps, and the cloth 103
The printed portion of the sheet is heated by the heating plate 114 from the back side of the drying section 125, and
It is dried by the hot air supplied / exhausted by the hot air duct 115 on the front side. Then, in the second printing unit 111 ', the overprinting is performed in the same manner as the first printing unit 111.

Here, the ink jet head 113 used in the ink jet printing apparatus applied to this embodiment is
Each head has 1408 ejection ports. 14
Of the 08 ejection openings, 1344 are used for printing, and 32 ejection openings at each end of the inkjet head 113 are not used for normal printing. By shifting the 1344 ejection openings used for printing by the width of the 32 ejection openings at both ends, it is possible to electrically correct mechanical displacement when a plurality of inkjet heads are mounted on the same carriage.

In the ink jet textile printing apparatus as applied in this embodiment, printing is performed on a printing medium which is continuous in the transport direction, and there is a case where the maximum length reaches 300 m. Such continuous paper (continuous cloth) is unwound from a rolled-up state and supplied to the textile printing apparatus, but is continuously supplied from another apparatus such as a pretreatment apparatus. It doesn't matter. In addition, the inkjet printing apparatus of this embodiment can print a continuous cloth of about 3000 m in about 50 hours by achieving 1 m of printing in the transport direction in 1 minute.

In the textile printing apparatus of this embodiment, eight heads achieve a print duty of 100%, and each head prints at a duty of about 12.5%.

With such a structure, for example, when printing is performed on the cloth 103 made of a mixture of cotton and polyester, the heads 1 arranged on the left and right sides in FIG.
The ink ejected from each of 13 and 113 'has the same color tone but different compositions. That is, the head 113 'ejects the ink containing the disperse dye, which has good dyeing suitability for cotton. Also, heads 113 and 1
In overprinting with 13 ', the respective inks forming the same pixel are deposited on the cloth 103 at substantially the same location.

First and second printing units 111 and 11
The cloth 103 on which printing has been completed in 1 ′ is dried again by the post-drying unit 126 similar to the above-described drying unit 125, cut into a predetermined size by the cutting device 117, and then sequentially stacked on the tray 118. Then, the cloth 103 placed on the tray 118 is taken out from the apparatus, and is subjected to color development, washing, and drying by a batch process to be a product.

FIG. 2 (a) is a sectional view of the ink jet heads 113, 113 ', and FIGS. 2 (b), (c).
6D and 6D are views for explaining the temperature distribution around the ink paths of the heads 113 and 113 '.

The ink jet heads 113 and 113 'are arranged along the direction perpendicular to the paper surface of FIG.
Thousands of ink passages 2 and ejection openings 2A forming an opening end at one end thereof are formed, and the figure shows a cross section along one of the ink passages 2. Ink is supplied (refilled) from the common liquid chamber 3 communicating with each ink path 2 by a capillary phenomenon in accordance with the ejection operation of each ink path or the like, and each ink path 2 is filled with ink. In this state, the discharge heater 4
When a pulse voltage is applied to the ink, it is instantaneously heated by the generated heat, and the bubbles 5 generated in the ink thereby eject an ink droplet 5'from the ejection port 2A. Cloth 1 as a material to be printed of the ejected ink droplet 5 '
03 (see FIG. 1), predetermined ink dots are formed.

The discharge heater 4 is formed on the surface of a base such as silicon, which is formed on the upper layer of the base plate 6. A water jacket 7 is attached to the back surface (downward in the figure) of the base plate 6. The water jacket 7 has cooling water 8 therein, and the cooling water 8 is circulated by a pump 10 so that the base plate 6
It is possible to take heat from the back surface of the head and cool the heads 113 and 113 '. The cooling water 8 is adjusted to a predetermined temperature by a water temperature controller 9 during its circulation. As the water temperature controller 9, a circulating liquid cooler Carry Cool (manufactured by Orion Machinery Co., Ltd.) is used.

FIG. 2B shows the temperature distribution of the ink passage 2 when printing is not performed. That is, the vertical direction in the figure shows the thickness direction of the base plate 6,
The bottom surface of the ink path 2 and the base plate 6 in that direction
3 shows the temperature distribution between the rear surface and the back surface. In the temperature distribution shown in FIG. 2B, since the heater 4 does not generate heat, the temperature of the entire head is uniform according to the temperature of the cooling water 8. Therefore, the ejection of ink is started from the state where the temperature of the portion of the ink passage 2 is the temperature Tw 'of the cooling water 8.

FIG. 2C shows the temperature distribution at the same place as above when printing is performed. That is, since the heater 4 generates heat and ink is ejected during printing,
A temperature distribution as shown in the figure occurs depending on the discharge duty and the like. For example, when the printing ratio is high (for example, 100%) and the ink is continuously ejected from the ejection port 2A (when the ejection duty is high), such as when printing is performed over the entire surface of the print medium, As shown in FIG. 2C, the portion of the ink passage 2 greatly increases by ΔT ′ with respect to the temperature of the cooling water. On the other hand, when the discharge duty is low, the degree of temperature rise is small as shown by ΔT ″ in the figure.

The cooling water temperature Tw 'is adjusted to a predetermined temperature by the temperature controller 9 in response to such temperature fluctuation of the ink passage 2. That is, when the target temperature range which is the allowable range of the temperature of the ink path 2 in which the above-mentioned print density fluctuation and density unevenness do not occur is T ₀ , the temperature Tw ′ is set near the lower limit of the temperature range. With this configuration, a base plate 6 having a high thermal conductivity is used and the thickness thereof is reduced to enhance the cooling efficiency of the cooling water 8 to the ink passages 2 and the discharge duty is maximum and the maximum temperature rise occurs. Even in this case, the target temperature range T ₀ should not be exceeded.

In FIG. 2 (c), the target temperature range T ₀ is shown as having a relatively wide range, but this range is obtained from the allowable range such as print density variation as described above. In fact, in the case where there is no cooling device, the temperature Tm far exceeding the ink ejection limit temperature Tp.
It only needs to be in the temperature range as a result of suppressing the temperature rise up to, and the width is relatively small. Further, the ejection limit temperature Tp is a temperature at which when the temperature exceeds this temperature, the bubbles generated by the thermal energy of the heater 4 are not extinguished and the next ink droplet cannot be ejected. Furthermore, since the back surface of the base plate 6 is in contact with the cooling water 8 whose temperature is kept constant, the above-mentioned conventional examples 1) to 3), that is,
Compared with the case where the back surface of the base plate is in contact with the outside air and the back surface of the base plate also rises in temperature, the temperature change width of the inkjet heads 113 and 113 'is much smaller.

By the way, as a result of the continuous printing operation in the industrial printing apparatus such as textile printing, as shown in FIG. 2D, the temperature Tw 'of the cooling water 8 in the water jacket 7 is shifted due to heat accumulation in the base plate. In some cases, it may be difficult to control the temperature of the ink passage 2 within the target temperature range T ₀ when reaching Tw ″. Therefore, in the present embodiment, the temperature on the rear surface of the base plate 6, that is, the portion in contact with the cooling water is The sensor 11 is attached, and the increase in the average temperature of the base plate obtained from the sensor 11 is converted into the operating power of the pump 10 by the flow rate controller 12 so as to increase the flow rate of the cooling water per unit time. It is possible to raise the temperature of the ink passage 2 and control the temperature of the ink passage 2 within the target temperature range T ₀ .
Using a diaphragm pump, the flow rate controller 12 controls the flow rate by changing the rotation speed and stroke amount of the pump by adjusting setting means such as knobs provided on the diaphragm pump.

In the present embodiment described above, in the industrial printing apparatus, when the required level for the print density or the uneven density is not so great, or when the required level is strict, the ejection duty does not change so much, for example, Display color filter manufacturing equipment,
Alternatively, when the discharge duty is low, for example, in the case of printing a special pattern for printing such as printing initials on a shirt cloth, it can be sufficiently applied as a configuration for controlling the temperature of the inkjet head.

In the above description, the position where the temperature sensor 11 is arranged is the back surface of the base plate, but the position where the temperature sensor 11 is arranged is not limited to this, and may be any position as long as the temperature reflecting the temperature of the ink passage 2 can be detected. Further, the means for obtaining the temperature information of the inkjet heads 113 and 113 'is not limited to the temperature sensor, and the head temperature may be estimated based on, for example, the cumulative number of ejections within a predetermined time.

That is, according to the first embodiment, it becomes possible to construct an industrial ink jet printing machine having a relatively large number of ejection openings and a high print duty, and the temperature fluctuations of the print heads 113 and 113 'are within a certain range. Can fit in. However, in order to make the temperature of the long print head having more ejection ports uniform and constant, the following embodiment can be further applied.

(Second Embodiment) FIGS. 3A, 3B and 3C are views for explaining a second embodiment of the present invention.

In the present embodiment, in addition to the above-described first embodiment, as shown in FIG. 3A, cumulative print data for a certain period for each ink path is stored in the ejection duty recording unit 201, and the calculation unit 202 is used. A necessary cooling water flow rate is calculated from the discharge duty for each ink path and the cooling water flow rate table 203, and the pump 204 is controlled. It should be noted that the table 203 outputs data relating to the flow velocity and direction of the cooling water with the discharge duty and the cooling water temperature as addresses, for example.

For example, as shown in FIG. 3B, when the temperature distribution is generated between the ink paths due to the uneven discharge duty of the print head 113 or 113 ', the calculation unit 202 obtains from the discharge duty recording unit 201. Know the temperature gradient of the head by the duty gradient,
The flow rate is calculated with reference to the flow rate table 203 based on this temperature gradient and the cooling water temperature Tw '. At the same time, when the temperature gradient has a certain gradient, the direction of flowing the cooling water is controlled so as to flow from the lower temperature side to the higher temperature side. As a result, the temperature change of the cooling water itself in the print head can be reduced, and the target temperature range can be made narrower T ₀ ′ as shown in FIG. The control of the direction of flowing the cooling water can be performed by using, for example, a two-pump, three-way valve configuration.

As described above, in the present embodiment, the head temperature can be controlled extremely accurately by correcting the heat generation deviation between the ink paths due to the cumulative ejection duty. As a result, the printing cannot be disabled, and the print density and the color tone can always be reproduced extremely accurately, and the density unevenness can be reduced.

In the above description, the distribution of the discharge duty is detected to indirectly know the temperature distribution of the head. However, a plurality of temperature sensors are provided in the head to directly measure the temperature between the discharge ports. It may be one that knows the distribution.

(Third Embodiment) FIG. 4 is a block diagram for explaining the third embodiment of the present invention.

In this embodiment, the ink jet head 11 is used.
3, 113 'are provided with a plurality of water jackets 302, a plurality of pumps 303 corresponding to them, and a pump control unit 304 for controlling the respective pumps. That is, the pump control unit 304 has the arithmetic processing unit 305.
Determine the pump output and flow rate according to the data output of.
As a result, the long inkjet head 11 has a large difference in temperature distribution of the water tubes in the inkjets 113 and 113 '.
3,113 'can be divided and cooled, and a structure for reducing the difference in temperature distribution is provided.

In response to this, the arithmetic processing unit 305 controls the flow rate and flow direction of the cooling water based on the discharge duty recording section 306 and the flow rate table 307 shown in the second embodiment, for each water jacket. Control.
At the same time, temperature correction is performed at regular intervals based on the detection output of the temperature sensor 308 attached to the water jacket 302. That is, in order to reduce the difference in the detected temperature data, the flow rate table 307 is rewritten or the set temperature of the water temperature controller 309 is corrected based on the detected temperature. This makes it possible to realize maintenance-free head temperature. Further, particularly in the printing apparatus during continuous operation, the main processing unit 304 performs processing such as cooling water leakage detection, circulation pump 303 rotation detection, and temperature sensor over-temperature detection, so that the main cooling processing system By transmitting the abnormality to the apparatus body control unit 310, the reliability of the entire apparatus can be improved. The set temperature is about 40 ° C., but may be a temperature in a range that does not affect normal printing, for example, about 45 ° C.

The above first, second and third embodiments are as follows.
This is an application example to an inkjet device that is greatly affected by heat accompanying ejection of a print head, that is, an inkjet device that ejects ink by bubbling the ink, but the present invention is not limited to this method. For example, in addition to the thermal transfer method described above, the present invention can be applied to a so-called piezo method inkjet apparatus that ejects ink by utilizing the strain effect of a piezoelectric element.
Even in the case of this piezo system, in the case of a head having a large number of ejection ports, the heat of the print head becomes a big problem as in the ink jet printing apparatus of the above system. In this case, in the case of the piezoelectric element as the electromechanical element, since only a part of the energy applied as the ejection signal is converted into mechanical energy, most of the other energy that is not converted becomes heat, which is relatively high. The head temperature rise may be large.

Although various liquids can be used as the cooling water, pure water is used in consideration of environmental protection and the like.

Next, the entire process of ink jet printing recording will be described. Using the inkjet printing apparatus described above, the cloth is dried (including natural drying) after the inkjet printing process. Then, a step of diffusing the dye on the fabric fiber and reactively fixing the dye on the fiber is performed. By this step, sufficient color development and fastness due to dye fixation can be obtained.

This diffusion and reaction fixing step may be a conventionally known method, for example, a steaming method. In addition,
In this case, the cloth may be subjected to an alkali treatment in advance before the printing step.

Then, in the post-treatment step, the unreacted dye and the substance used for the pre-treatment are removed.
Finally, the recording is completed through a finishing process such as defect correction and ironing.

In particular, as a fabric for ink-jet printing, (1) the ink can be developed to a sufficient density,
(2) High ink dyeing rate, (3) Ink dries quickly on the cloth, (4) Rare ink bleeding on the cloth is small, (5) In-apparatus It is required to have excellent performance such as excellent transportability. In order to satisfy these required performances, in the present invention, the fabric may be pretreated in advance, if necessary. For example, Japanese Unexamined Patent Publication (Kokai) No. 62-53492 discloses fabrics having an ink receiving layer, and Japanese Patent Publication No. 3-46589 proposes fabrics containing a reduction inhibitor and an alkaline substance. There is. Examples of such pretreatment include a treatment in which the cloth is made to contain a substance selected from alkaline substances, water-soluble polymers, synthetic polymers, water-soluble metal salts, urea and thiourea.

Examples of the alkaline substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide,
Examples thereof include amines such as mono-, di- and triethanolamine, and carbonic acid or alkali metal bicarbonate such as sodium carbonate, potassium carbonate and sodium bicarbonate. Furthermore, there are organic acid metal salts such as calcium acetate and barium acetate, and ammonia and ammonia compounds. Also, sodium trichloroacetate, which becomes an alkaline substance under steaming and dry heat, can be used. Particularly preferred alkaline substances are sodium carbonate and sodium bicarbonate used for dyeing reactive dyes.

As the water-soluble polymer, starch substances such as corn and wheat, cellulosic substances such as carboxymethyl cellulose, methyl cellulose and hydroxyethyl cellulose, sodium alginate, gum arabic,
Locust bean gum, tragacanth gum, guar gum,
Examples include polysaccharides such as tamarind seeds, protein substances such as gelatin and casein, and natural water-soluble polymers such as tannin-based substances and lignin-based substances.

Examples of synthetic polymers include polyvinyl alcohol compounds, polyethylene oxide compounds, acrylic acid water-soluble polymers, maleic anhydride water-soluble polymers, and the like. Among these, polysaccharide polymers and cellulose polymers are preferable.

Examples of the water-soluble metal salt include compounds such as halides of alkali metals and alkaline earth metals which form typical ionic crystals and have a pH of 4 to 10. As a typical example of such a compound, for example, in the case of an alkali metal, NaCl, Na ₂ S
O ₄ , KCl, CH ₃ COONa and the like can be mentioned, and as the alkaline earth metal, CaCl ₂ and Mg.
Cl _{2 and the} like can be mentioned. Of these, salts of Na, K and Ca are preferable.

The method of incorporating the above substances and the like into the cloth in the pretreatment is not particularly limited, and examples thereof include a dipping method, a pad method, a coating method and a spraying method which are usually performed.

Further, the printing ink applied to the ink-jet printing cloth merely adheres to the cloth when it is applied to the cloth. Therefore, the step of fixing the dye in the ink such as the dye to the fiber is subsequently performed. Is preferred. Such a fixing step may be a conventionally known method, for example, a steaming method, an HT steaming method, a thermofix method,
When a cloth which has been previously alkali-treated is not used, the alkali pad steam method, the alkali blotch steam method, the alkali shock method, the alkali cold fix method and the like can be mentioned. Further, the fixing step may or may not include a reaction step depending on the dye, and the latter example includes one in which fibers are impregnated and are not physically separated. Any appropriate ink can be used as long as it has a required dye, and the ink is not limited to a dye and may include a pigment.

Further, the unreacted dye and the substance used in the pretreatment can be removed by washing after the above reaction fixing step according to a conventionally known method. In addition, it is preferable to use a conventional fixing treatment together with this cleaning.

The printed matter which has been subjected to the above-mentioned post-processing step is then cut into a desired size, and the cut pieces are used for obtaining a final processed product such as sewing, adhesion, welding and the like. After that, clothes such as dresses, dresses, ties, swimwear, duvet covers, sofa covers, handkerchiefs, curtains, etc. can be obtained. A method of processing cloth by sewing or the like to make clothes or other daily necessities is a conventionally known technique.

As the printing medium, cloth, wall cloth, threads used for embroidery, wallpaper, paper, OHP film, plate-like materials such as alumite, and various other materials that can be applied with a predetermined liquid by using an inkjet technique. The cloth includes all kinds of woven fabrics, non-woven fabrics, and other fabrics regardless of materials, weaving methods, and knitting methods.

The present invention is not limited to the above-mentioned ink jet printing method, but various printing methods can be adopted. When the ink jet printing method is adopted, among them, heat is used as energy used for ejecting ink. An excellent effect is brought about by using a method of providing a means for generating energy and causing a change in the state of the ink by the thermal energy, that is, a bubble jet type print head and a printing device proposed by Canon Inc. This is because such a method can achieve high density and high definition printing.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the print information and causing a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling occurs on the heat acting surface of the print head. This is effective because bubbles can be generated in the liquid (ink) corresponding to this drive signal one-to-one as a result. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124, which is an invention relating to the temperature rise rate of the heat acting surface, are adopted, more excellent printing can be performed.

In addition to the combination of the ejection port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, the structure of the print head is not limited to the above. The present invention also includes a configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the heat acting portion is arranged in a bending region. In addition, for multiple electrothermal converters,
Japanese Unexamined Patent Publication No. 59-123670, which discloses a configuration in which a common slit is used as the discharge portion of the electrothermal converter, and Japanese Laid-Open Patent Publication No. 59-63, which discloses a structure in which an opening for absorbing a pressure wave of thermal energy is associated with the discharge portion. The effects of the present invention are effective even with a configuration based on Japanese Patent Laid-Open No. 138461. That is, according to the present invention, regardless of the form of the print head, printing can be surely performed efficiently.

In addition, it goes without saying that the print head can be constructed according to the form of the printing apparatus, and in the case of the so-called line printer form, the ejection ports are arranged over a range corresponding to the width of the print medium. It should be one. Further, as the serial type print head as in the above example, the print head fixed to the apparatus main body or mounted on the apparatus main body enables electrical connection with the apparatus main body and supply of ink from the apparatus main body. The present invention is also effective when a replaceable chip type print head or a cartridge type print head in which an ink tank is integrally provided in the print head itself is used.

Further, as the constitution of the printing apparatus of the present invention, it is preferable to add ejection recovery means of the print head, preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or suctioning means for the print head, preheating means for heating using an electrothermal converter or another heating element or a combination thereof, and printing Preliminary ejection means for performing another ejection can be mentioned.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet method, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change from the solid state of the ink to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, the ink is liquefied by applying heat energy according to the print signal,
The present invention is also applicable to the case of using an ink that has the property of being liquefied only when heat energy is applied, such as one that ejects liquid ink or one that has already started to solidify when it reaches the printing medium. . The ink in such a case is in a state of being held as a liquid or a solid in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. 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 present invention may be used as an image output terminal of an information processing device such as a computer, or may be in the form of a copying apparatus combined with a reader or the like.

[0075]

As described above, according to the present invention, the flow rate of the cooling water can be changed according to the temperature change of the print head. Therefore, when the temperature of the head is excessively increased, the flow rate of the cooling water is increased. To increase the heat dissipation from the head,
As a result, the temperature of the print head can be controlled within a certain range.

Further, since the flow rate and direction of the cooling water can be controlled according to the temperature distribution of the print head, the temperature of the print head can be controlled within a certain range, and the variation range of the temperature distribution of the print head can be controlled. It can be small.

As a result, variations in print density and density unevenness can be suppressed, and color reproducibility can be improved.

[Brief description of drawings]

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

2A to 2D are diagrams illustrating temperature control of an inkjet head in the first embodiment of the present invention.

3A to 3C are diagrams illustrating temperature control of an inkjet head in a second embodiment of the present invention.

FIG. 4 is a diagram illustrating temperature control of an inkjet head according to a third embodiment of the present invention.

[Explanation of symbols]

2 ink passage 2A discharge port 3 common liquid chamber 4 heater 5 air bubble 5'ink drop 6 base plate 7 water jacket 8 cooling water 9,309 water temperature controller 10,303 circulation pump 11,308 temperature sensor 12 flow controller 113,113 ' Inkjet head (print head) 201, 306 Ejection duty recording unit 202 Calculation unit 203, 307 Flow rate table 305 Calculation processing unit

Claims (7)

[Claims] 1. In a printing apparatus that uses a print head and prints on a print medium by the print head, cooling means for circulating a liquid to cool the print head, and information on the temperature of the print head are provided. A printing apparatus comprising: a head temperature detecting means for obtaining the temperature; and a flow rate control means for changing the flow rate of the liquid by the cooling means based on the head temperature information obtained by the head temperature detecting means. 2. In a printing apparatus that uses a print head having a plurality of print elements and prints on a print medium by the print head having the plurality of print elements, a liquid is circulated to cause the plurality of print elements to flow. Cooling means for cooling the print head, a head temperature distribution detecting means for obtaining information on the temperature of the print head and its distribution corresponding to the positions of the plurality of print elements, and the print obtained by the temperature distribution detecting means. A printing apparatus comprising: a cooling liquid control unit that controls the flow rate and direction of the liquid by the cooling unit based on information about the temperature of the head and its distribution. 3. The printing apparatus according to claim 1, wherein the head temperature detecting unit has a temperature sensor provided in the print head. 4. The printing apparatus according to claim 2, wherein the head temperature distribution detecting unit obtains the temperature of the print head and its distribution from print duty of each of the plurality of print elements. 5. The print head is an ink jet head that uses the thermal energy generated by the print element to generate bubbles in the ink and ejects the ink as the bubbles are generated. The printing device according to claim 1. 6. The printing apparatus according to claim 1, wherein the print head is a thermal transfer head that transfers ink to a print medium by thermal energy generated by the print element. 7. The ink jet head according to claim 1, wherein the print head has a piezoelectric element as the print element and ejects ink by utilizing a distortion effect of the element. The printing device according to.