JPH0732605A - Ink cartridge and manufacture therefor - Google Patents

Abstract

PURPOSE:To prevent printed characters from bleeding due to increasing surface tension of ink, and ink characteristics from being unstable due to properties of an absorber (foam) by impregnating an absorber with ink which contains surfactant for use as an ink cartridge in ink jet recording. CONSTITUTION:This ink cartridge, which is used in an ink jet printer, is provided with a cartridge case 1, an ink absorber 3 impregnated with ink whose surface tension is adjusted to 32dyne/cm or less, and a cartridge case cover 2. The surface tension of ink which impregnates the ink absorber 3 is (A+3.0) dyne/cm or less to the surface tension A of single ink. Manufacture thereof consists of at least (1) a process of immersing the ink absorber 3 in the solution which contains surfactant (0.1-10weight% and (2) a process of injecting ink which contains surfactant in a cartridge which stores the ink absorber 3 immersed in surfactant solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink cartridge which serves as an ink supplier in ink jet recording and a method for manufacturing the ink cartridge.

[0002]

2. Description of the Related Art Conventionally, an ink cartridge, which serves as an ink supply member in ink jet recording, generally has a structure in which a foam compressed and stored is impregnated with ink. The ink held in the foam is supplied to the head from the ink supply unit of the ink cartridge.

Conventionally, as described in Japanese Patent Application Laid-Open No. 64-26452 and the like, a typical polyether type polyurethane foam is used as an ink reservoir in a kind of ink jet printing cartridge and is made into a mesh and a felt. It is known that a foam (ink absorber) is used. However, since non-volatile impurities remain in this foam, it may contaminate the ink when used in an ink cartridge or adversely affect the fluid properties of the ink. The above-mentioned JP-A-64
No. 26,452 discloses a method for determining the cleanliness of a foam, and JP-A No. 64-26452 (US Pat. No. 4,824,887) discloses an apparatus for cleaning the foam.

The former requires that the amount of non-volatile residue contained in the foam after washing is 0.2% by weight or less based on the foam, and that the surface tension of the ink in which the foam is immersed is higher than 40 dyne / cm. , Or the reduction in surface tension must be less than 7 dyne / cm. The latter is also a recirculation type closed-loop automatic pollutant removal using Freon 113 as a solvent from the viewpoint that simply rinsing the foam with a solvent is not enough to remove the non-volatile residues contained in the foam. The system is disclosed. However, both are only concerned with the removal of non-volatile residues in the foam that cause clogging of the printhead outlets.

[0005]

According to the above-mentioned conventional example, foam cleaning is carried out with a chlorofluorocarbon solvent. However, CFC-based solvents have high volatility and are harmful to the environment, so special cleaning equipment is required, and since they are poorly compatible with ink, if they remain in the foam, there is a high possibility that they will adversely affect printing. It was Further, in particular, when the foam washed by the above-mentioned technique is used as an absorbent of an ink containing a surfactant, the surface tension of the ink is increased, and as a result, bleeding occurs in the overprinted portion such as color printing. There was a problem of deterioration of print quality. Further, depending on the properties of the foam used, there is a problem that stable ink characteristics and thus stable printing quality cannot be obtained.

An object of the present invention is to eliminate the above-mentioned problems and to provide an ink cartridge capable of expanding the proper range of the ink absorber and the ink and obtaining a sufficient printing quality.

Another object of the present invention is to manufacture an ink cartridge which suppresses an increase in the surface tension of the ink impregnated in the ink absorber, which causes deterioration of print quality, in order to solve the problems of the prior art. To provide a method.

[0008]

The ink cartridge of the present invention is used in an ink jet printer comprising at least a cartridge case, an ink absorber impregnated with ink whose surface tension is adjusted to 32 dyne / cm or less, and a cartridge case lid. In this ink cartridge, the surface tension A of the ink alone has a surface tension (A + 3.0) dy of the ink impregnated in the ink absorber.
It is characterized in that it is ne / cm or less.

Further, in the ink cartridge of the present invention, the surface tension A of the ink alone has a surface tension of (A + 1.0) dyne / cm of the ink impregnated in the ink absorber.
It is characterized by the following.

Further, the surface tension A of the ink containing acetylene glycol and the surface tension A of the ink alone has a surface tension (A + 3.0) d of the ink impregnated in the ink absorber.
It is characterized in that it is yne / cm or less.

Further, in the present invention, the surface tension A of the ink containing the acetylene glycol and the surface tension A of the ink alone is (A + 4.
0) dyne / cm or less.

The ink cartridge of the present invention is characterized by at least a cartridge case, an ink absorber pretreated with a surfactant solution, ink, and a cartridge case lid.

Furthermore, the method for producing an ink cartridge of the present invention comprises a step of immersing the ink absorber in a solution containing at least 0.1 to 10% by weight of a surfactant, and an ink absorber immersed in the surfactant solution. The method is characterized by having a step of injecting an ink containing a surfactant into a cartridge accommodating the.

[0014]

When the foam that becomes the ink absorber is impregnated with the ink containing the surfactant, the surfactant in the ink is trapped by the foam, so that the ink passing through the foam has a reduced surface tension due to the reduction of the surfactant. To rise.
The surface tension of the ink has a great influence on the print quality, but particularly in color printing, it shows a significant influence on the quality of the overprinted portion, and the greater the surface tension of the ink, the more easily the bleeding occurs. The increase in the ink surface tension can be suppressed by carrying out a treatment for preliminarily holding an amount of the surfactant corresponding to the amount captured in the foam, and further, good printing quality can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the cartridge of the present invention will be described with reference to FIG. FIG. 1 is an exploded view of an ink cartridge which is an embodiment of the present invention. The cartridge comprises a cartridge case 1, an ink absorber 3 and a cartridge case lid 2, and the ink absorber 3 is attached to the cartridge case 1.
It is formed by adhering or welding the cartridge case lid 2 after the insertion. The ink is impregnated in and held in the ink absorber 3, and is supplied to the head through the supply port 4.

A filter 5 is provided at the boundary between the ink chamber and the supply port to remove foreign matter mixed in the ink which may cause clogging when mixed in the head.

Next, the ink absorber used in the ink cartridge of the present invention will be described in detail. This ink absorber is a polymeric elastic porous body having open cells inside, and any foam that has ink resistance and does not deteriorate by ink can be used, but polyurethane foam is preferably used. The polyurethane foam is preferably one in which the film-like substance generated between the cells has been removed by causing the gas to explode by adding combustion gas to it.
Depending on the case, this process may not be performed.

Further, it is preferable that the foam is further compressed to control the density, but this may not be performed in some cases.

The resulting foam may contain a considerable amount of unreacted substances and film-like substances that have been separated due to explosion and remain between the cells, and cleaning is performed to remove these substances. Wash the ink absorber at room temperature to 80 ℃
It is performed by repeating the kneading operation in pure water.
It is then dehydrated by centrifugation and dried in the oven.

Next, a method of processing for holding the surfactant in the ink absorber will be described. 0.1% ink absorber
It is dipped in a treatment liquid in which 10% by weight of a surfactant is dissolved, and a rubbing operation is repeated in order to uniformly impregnate the ink absorber with the treatment liquid in a solution at room temperature to 80 ° C.
This kneading operation may be omitted if the treatment liquid is evenly impregnated in the ink absorber. The treated ink absorber may be washed before drying for the purpose of removing excess surfactant. It is then dehydrated by centrifugation and dried in the oven. Drying of the ink absorber after washing and processing is preferably completely dried in order to prevent a change in the composition of the ink filled in the cartridge. However, at high temperatures, the ink absorber material may deteriorate,
At low temperatures, it takes a long time to dry and the efficiency is poor.
It is preferable to set appropriate conditions depending on the properties of the ink absorber used.

Next, the treatment liquid used for the treatment of holding the surfactant in the ink absorber will be described. The treatment liquid is a solution of a surfactant dissolved in pure water or another solution, and the surfactant used for this treatment may be any of cationic, anionic, amphoteric and nonionic. When the treated ink absorber is impregnated with ink, the surfactant retained in the ink absorber is likely to dissolve in the ink and affect the characteristics of the ink. The same type is preferable, but different types can also be used and can be used in combination with other surfactants.

The concentration of the surfactant in the treatment liquid is 0.1-10.
It is preferably in the range of 0% by weight, more preferably in the range of 0.5 to 5.0% by weight. When the surfactant concentration is within the above range, the surfactant is retained in the ink absorber in an adequate amount, and the ink cartridge using this ink absorber has little change in ink characteristics and does not deteriorate print quality.

When the concentration of the surfactant in the treatment liquid is below the above range, the amount of the surfactant in the ink is reduced due to the insufficient amount of the surfactant held in the ink absorber, and the ink characteristics are changed. Further overprinting is not preferable because bleeding may occur in a portion printed later. Further, if the concentration of the surfactant in the treatment liquid exceeds the above range, the amount of the surfactant in the ink is increased due to the excessive amount of the surfactant held in the ink absorber, and the ink characteristics are likely to change. Furthermore, the high-concentration surfactant may come into contact with the cartridge and the parts with which the ink comes into contact, which may deteriorate the parts, which is not preferable. Furthermore, the inclusion of an excessive amount of surfactant is not preferable because it may cause nozzle clogging. Also,
Excessively increasing the concentration of the surfactant in the treatment liquid leads to an increase in cost and is not efficient.

When the treatment liquid is continuously treated, foreign matters are mixed in from the ink absorber and characteristics of the treatment liquid such as a decrease in the concentration of the surfactant are changed. Variation easily occurs. Solid foreign matter mixed in the treatment liquid can be easily removed by filtering the treatment liquid with a filter, but if the surfactant concentration of the treatment liquid falls below the specified range, sufficient treatment is not possible. Since it is not performed, it is preferable to manage the processing liquid using the following method.

After the treatment liquid is fractionated and foreign substances are removed by filtration, the properties of the treatment liquid are measured, and the treatment liquid is controlled depending on whether or not these characteristics are within a specified range. Properties suitable for liquid management include specific gravity, electrical conductivity, pH, and UV spectrophotometry. It is preferable that the specified range of each characteristic is appropriately set according to the properties of the ink absorber to be used.

A treatment time of several minutes to several hours is sufficient for a treatment solution having high permeability. Further, when the temperature of the processing liquid is higher than room temperature, the processing time can be shortened.

After the treatment by the above-mentioned method, it is necessary to confirm whether the ink absorber holds a proper amount of the surfactant. A method for controlling the quality of the ink absorber that has been treated here will be described.

The amount of the surfactant retained on the ink absorber by the treatment is determined by measuring the weight of the ink absorber which has been thoroughly washed with pure water after the treatment and dried completely. It is possible to manage by the change value. It is preferable that this value is appropriately set according to the properties and size of the ink absorber used.

Next, the ink used in the present invention will be described.

As the ink used in the present invention, both non-aqueous ink and water-based ink can be used, and water-based ink is particularly preferable. The water-based ink basically consists of water, a water-soluble organic solvent, an additive, and a coloring material. As the surfactant as an additive, any of anionic, cationic, amphoteric and nonionic can be used, but a surfactant made of acetylene glycol which can impart penetrability to paper to the ink is particularly preferable. preferable. The ink absorber is impregnated with this ink to form an ink cartridge.

The ink cartridge of the present invention and the method for manufacturing the same will be described in detail below with reference to examples.

Example 1 0.05% by weight of surfactant Surfynol 465,
0.1 wt%, 0.3 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 3.0 wt%,
5.0% by weight, 7.0% by weight, 10.0% by weight, 13.
An aqueous solution containing each concentration of 0% by weight was prepared. Put polyurethane foam in this liquid and repeat the rubbing operation about 20 times to impregnate the liquid into the liquid,
It was left in an environment of 40 ° C., 50 ° C. and 70 ° C. for 30 minutes, 1 hour, 2 hours and 3 hours. After standing, it was dehydrated by centrifugation and placed in an oven at 70 ° C. for 16 hours to dry. This foam was put in a cartridge case, a lid was welded to form a cartridge, and 30 ml of each of ink 1 or ink 2 was filled.

Ink 1 Direct black 1545 5% by weight Glycerin 5% by weight Diethylene glycol 10% by weight Surfynol 465 1% by weight Ion-exchanged water remaining ink 2 Direct yellow 86 2% by weight Glycerin 15% by weight Diethylene glycol 10% by weight Surfynol 465 0 0.8 wt% ion-exchanged water remaining amount The cartridge filled with the ink was placed at 70 ° C. for 24 hours, and then the ink was extracted to measure the surface tension. Compared to the surface tension of ink 1 alone of 28.5 dyne / cm or the surface tension of ink 2 alone of 32.0 dyne / cm,
Using the change amount (x) of each ink surface tension after filling the cartridge and leaving it as an evaluation standard, ⊚: −1.0 <x <+1.0 ∘: −3.0 <x <−1. 0, +1.0 <x <+3.0 Δ: −5.0 <x <−3.0, +3.0 <x <+5.0 ×: x <−5.0, +5.0 <x (unit Is dyne / cm), and the above results are summarized in Table 1.

[0034]

[Table 1]

Example 2 Print evaluation was performed using the same ink as that used in Example 1 for surface tension evaluation. In the printing, in color printing, ink 2 which is a yellow ink is used as a base to perform solid printing first, and a pattern such as characters of ink 1 which is a black ink is superposed on the solid printing. The quality of printing with Ink 1 at this time was evaluated based on the presence or absence of bleeding.

The evaluation criteria are: ◎: No bleeding, etc. ○: Small bleeding, etc. (within the allowable limit) △: Medium bleeding, etc. (outside of the allowable limit) ×: Large bleeding, etc. The above results are summarized in Table 2. .

[0037]

[Table 2]

Example 3 The clogging property was evaluated using the same ink as that used in Examples 1 and 2. The clogging property was evaluated by the print stability depending on the presence or absence of ink flight deviation when printing was started after waiting for several seconds with the head not capped.

The evaluation criteria are as follows: ◎: No bends, etc. ○: Small bends, etc. (within allowable limit) △: Medium bends, etc. (outside allowable limit) ×: Occurrence of clogging, and the above results are summarized in Table 3. .

[0040]

[Table 3]

From the above Examples 2 and 3, in the print quality according to Example 2, when the content of Surfynol 465 in the treatment liquid is less than 0.5% by weight, the smaller the content, that is, the surface activity of the foam due to the treatment. It is clear that the smaller the amount of agent held, the more marked the occurrence of bleeding. Further, regarding the clogging property of Example 3, when the content of Surfynol 465 in the treatment liquid exceeds 5.0% by weight, the more the content of Surfynol 465 is, that is, the larger the amount of the surfactant retained in the foam due to the treatment, the more the ink bends. It is clear that, etc. are likely to occur. From the above, it is understood that it is preferable to retain the surfactant in the foam in an appropriate amount in the processing of the foam.

Further, combining the above results with Example 1,
If the print quality is free of bleeding or the like, and the print stability is free of ink flight bending or the like, or if the ink is bending within an allowable limit, the change in ink surface tension is ± 3.
It was less than 0 dyne / cm. Further, in the case where there is no bleeding in the print quality and there is no ink flight deflection in the printing stability, the change in the surface tension of the ink is ± 1.
It was less than 0 dyne / cm.

When the urethane foam is treated by the above method, the amount of the surfactant retained in the foam is governed to some extent by the concentration of the surfactant in the treatment liquid. The concentration of the surfactant in the treatment liquid is 0.1 to 10.0% by weight, and particularly 0.5 to
Good results were obtained at 5.0% by weight. The temperature at the time of treatment varies depending on the concentration of the surfactant in the treatment liquid, but the treatment efficiency can be improved by raising the temperature to a range that does not deteriorate the treatment liquid or deteriorate the foam. The time required for the treatment varies depending on the surfactant concentration of the treatment liquid and the temperature, but the effect reaches equilibrium within a certain period of time, and thus the equilibrium time is appropriate for efficient treatment.

Although the ink cartridge according to the present invention can be used for monochrome and color printing,
The above-described treatment for the ink absorber may be performed for each ink absorber that is impregnated with ink of all colors supplied as an ink cartridge or for each ink absorber that is impregnated with ink of all colors except black ink. Good.

Furthermore, the ink absorber treated by the method of the present invention can be used not only in an ink cartridge having a separate structure from the head but also in an ink cartridge in which the head and the ink cartridge are integrated.

[0046]

EFFECTS OF THE INVENTION According to the present invention, it is possible to suppress the elution of non-volatile impurities contained in the foam, which is the ink absorber, into the ink, and it is observed when an ink containing a surfactant is used. The increase in the surface tension of the ink due to the reduction in the amount of the surfactant and the deterioration in the print quality of the overprinted portion such as color printing are reduced, and the stable recording quality can be maintained.

Further, according to the present invention, it is possible to simultaneously perform the cleaning of the ink absorber for the ink cartridge and the holding of the surfactant by a simple method.

Further, according to the present invention, it is possible to reduce the equipment cost for cleaning the ink absorber for the ink cartridge, the cost of the cleaning liquid and the like.

[Brief description of drawings]

FIG. 1 is an exploded view of an ink cartridge of the present invention.

[Explanation of symbols]

 1 Cartridge Case 2 Cartridge Case Lid 3 Ink Absorber 4 Supply Port 5 Filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Serizawa 3-3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation

Claims (7)

[Claims] 1. An ink cartridge used in an ink jet printer comprising at least a cartridge case, an ink absorber impregnated with ink whose surface tension is adjusted to 32 dyne / cm (A) or less, and a cartridge case lid, the ink cartridge comprising: An ink cartridge in which the surface tension A of the ink alone is less than or equal to (A + 3.0) dyne / cm. 2. The surface tension A of the ink alone is such that the surface tension of the ink impregnated in the ink absorber is (A + 1.
The ink cartridge according to claim 1, wherein the ink content is 0) dyne / cm or less. 3. The surface tension A of the ink containing the acetylene glycol and the surface tension A of the ink alone has a surface tension (A + 3.0) dyn of the ink impregnated in the ink absorber.
The ink cartridge according to claim 1, wherein the ink cartridge has an e / cm or less. 4. The surface tension A of the ink containing acetylene glycol and the surface tension A of the ink alone has a surface tension (A + 1.0) dyn of the ink impregnated in the ink absorber.
The ink cartridge according to claim 1, wherein the ink cartridge has an e / cm or less. 5. An ink cartridge used in an inkjet printer, comprising at least a cartridge case, an ink absorber pretreated with a surfactant solution, ink, and a cartridge case lid. cartridge. 6. The ink cartridge according to claim 5, wherein the ink absorber is pretreated with a solution containing 0.1 to 10% by weight of a surfactant. 7. A step of placing an ink absorber in a solution containing at least 0.1 to 10% by weight of a surfactant, a cartridge containing the ink absorber in a surfactant solution, and A method for manufacturing an ink cartridge, comprising a step of injecting an ink containing an activator.