JP2006051761A - Ink supply method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet cartridge of a pit-in ink supply type having excellent ink-filling stability and high reliability. <P>SOLUTION: The ink-jet cartridge comprises a recording head having a liquid discharge port, a liquid storage chamber for storing a liquid to be supplied to the recording head, an ink-holding member for holding an ink by generating negative pressure in the liquid storage chamber, a liquid supply port to be connected to a main tank, which is provided at a part of the liquid storage chamber, a gas-liquid separation member to communicate with atmospheric air, which is provided at a part of the liquid storage chamber, and a gas communication port to communicate with atmospheric air through the gas-liquid separation member. In the ink supply method comprising supplying the ink to the ink-jet cartridge from the main tank by sucking the liquid storage chamber by negative pressure through the gas communication port, a liquid having higher surface tension than the ink is used when the ink is fed initially. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink supply method to an ink jet cartridge, and more particularly to an ink supply method to an ink cartridge using a pit-in ink supply method.

  As a representative example of the ink jet cartridge using the pit ink ink supply method, there is an ink jet cartridge described in Japanese Patent Laid-Open No. 2000-334982. The ink jet cartridge disclosed in Japanese Patent Application Laid-Open No. 2000-334982 is capable of taking ink into the inside from the intake port by a negative pressure introduced from the suction port, and allows gas to pass through the suction port without passing ink. A separation member is provided. This gas-liquid separation member serves as a full valve, and ink can be replenished easily and reliably.

Ink injection at the time of initializing a tank connected to a conventional ink jet cartridge is performed by sucking the inside of the tank with a vacuum pressure of 65 KPa or more and reducing the pressure, and performing ink injection with a pressure difference from the atmosphere.
JP 2000-334982

  In this cartridge equipped with a sub-tank that uses a gas-liquid separation member, the water-repellent treatment is performed on the ink contact surface of the gas-liquid separation member to improve the water repellency of the ink, and the ink of the gas-liquid separation member is improved by the surface tension of the ink. The ink is held on the contact surface, and the ink does not penetrate into the gas-liquid separation member. In this cartridge, if the vacuum pressure for ink injection at the initial time exceeds 30 KPa, the inside of the tank is made negative by suction from the suction port, so pressure is applied to the gas-liquid separation member and the surface tension of the ink cannot withstand. There is a possibility that ink permeates from the pore diameter of the fibrous structure of the liquid separation member and causes ink leakage from the gas-liquid separation member.

  For the above reasons, the ink injection is performed by setting the vacuum pressure for ink injection at the initial time in the pit-in method to be 30 KPa or less at the maximum.

  However, when the vacuum pressure is 30 KPa or less, there are further problems in ink injection at the initial stage.

  In the case where the density of the ink holding member used in the tank is high (for example, 0.085 g / cubic centimeter), if the ink injection vacuum pressure is 30 KPa or less, the initial ink holding member in the tank is not wet. Then, the ink does not uniformly travel around the holding member, and an ink non-filling portion is generated in the tank. As a result, once an unfilled portion occurs, even if ink is reinserted, it becomes difficult for the ink to flow around that portion, resulting in an insufficient amount of ink.

  Therefore, there is a need for a means that does not cause ink leakage from the gas-liquid separation member even when the ink injection at the initial time is a vacuum pressure of 30 KPa or more. SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet cartridge that uses a highly reliable pit-in ink supply system that is excellent in ink filling stability and that eliminates the above problems.

  In order to achieve the above object, the present invention provides a recording head having a liquid discharge port, a liquid storage chamber for storing liquid supplied to the recording head, and a negative pressure in the liquid storage chamber for holding ink. An ink holding member; a liquid supply port connected to a main tank provided in a part of the liquid storage chamber; a gas-liquid separation member communicating with the atmosphere provided in a part of the liquid storage chamber; and a gas-liquid separation member An ink jet cartridge that uses a gas-liquid separation member by supplying ink from a main tank by suctioning the liquid storage chamber at a negative pressure from the gas communication port. In this case, a liquid having a surface tension higher than that of the ink is used when the ink is injected at the initial stage.

  Further, the negative suction pressure in the liquid storage chamber at the time of ink injection at the initial time is 30 KPa or more.

  Further, the liquid used for the ink injection at the initial time has a surface tension of 40 mN / m or higher, which is higher than that of the ink.

  In addition, the density of the ink holding member in the liquid storage chamber is 0.085 g / cubic centimeter or less when the negative suction pressure in the liquid storage chamber during ink injection at the initial time is 30 KPa or more. .

  The gas-liquid separation member is a porous member.

  Further, the gas-liquid separation member is characterized in that a treatment having water repellency is performed.

  As described above, according to the method of the present invention, the liquid is injected into the tank at a negative pressure of 30 KPa or more in advance using a liquid having a surface tension higher than that of the ink, and the liquid is filled in the entire ink holding member. By replacing the liquid and the ink, the ink injection at the initial time is completed. As a result, in the ink injection at the initial time, the state of the ink flowing to the ink holding member is improved, the ink unfilled portion can be eliminated, and the ink Net amount in the tank at the initial time is stabilized. In addition, by eliminating the unfilled portion of ink, the amount of ink Net for each pit-in frequency is also stabilized. That is, it is possible to provide an ink jet cartridge that uses a highly reliable pit-in ink supply method that is excellent in ink filling stability.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a cross-sectional view of an ink jet cartridge according to a first embodiment of the present invention.

  Reference numeral 1 denotes a discharge unit for discharging liquid, and reference numeral 2 denotes a liquid storage chamber for storing the liquid supplied to the discharge unit. Reference numeral 3 denotes a liquid supply port connected to a main tank (not shown). 4 is a cover plate member for making the liquid storage chamber 2 a closed space, and a gas-liquid separation member 5 is provided on the inner surface of the cover plate member 4 on the liquid storage chamber 2 side. In the present embodiment, the liquid storage chamber 2 is filled with an ink holding member 6 that absorbs and holds ink. Reference numeral 7 denotes an air communication port connected to the suction pump. The gas-liquid separation member 5 in this embodiment uses a porous member, and the density of the ink holding member 6 in the liquid storage chamber 2 is 0.05 g / cubic centimeter.

  FIG. 2 is a diagram for explaining pit-in ink supply in this embodiment.

  As shown in FIG. 2, the ink B is supplied from the liquid supply port 3 into the liquid storage chamber 2 by performing the suction B from the air communication port 7 by the suction pump.

  In this embodiment, pure water (surface tension = 72.75 mN / m) is used as the liquid whose surface tension is higher than that of the ink at the time of initialization, and the suction pump pressure may be 30 KPa or more. At the maximum capacity of 67 KPa, the air in the liquid storage chamber 2 is sucked as much as possible, and the pure water is completely circulated through the entire ink holding member in the liquid storage chamber 2, so that the pure water in the liquid storage chamber 2 is purified. To fill up. Thereafter, by replacing with ink, the original ink density is restored.

  FIG. 3 is a diagram for explaining ink replacement. By sucking the pure water injected in FIG. 2 from the suction cap 8 mounted on the main body, the liquid is discharged from the nozzle, and the ink supply shown in FIG. 2 is performed. In this case, if the suction pressure from the suction cap 8 is 20 KPa or more, pure water can be discharged from the suction cap 8. Regarding the suction pressure of the ink supply, it is performed within the range of 5 to 20 KPa. Because, as described in the problem to be solved by the invention at the beginning, if the suction pressure is applied to 30 KPa or more, the surface tension of the ink cannot endure, and the ink penetrates from the pore diameter of the fibrous structure of the gas-liquid separation member. Is set to be less than 30 KPa, so a setting with a margin is made.

  As described above, by supplying and discharging the pure water, which is a liquid having a surface tension higher than that of the ink, once and repeatedly three times or more, the necessary ink density can be secured, and the ink supply at the initial stage is completed. . The relationship between the number of ink replacements and the ink density is 1.35, 1.64, 1.67, 1.68 when the replacement times 1 to 4 are expressed in order as OD values, and the ink density 1 before replacement is 1 Compared to .76, it is slightly lower, but there is no problem in actual images (the above are all OD values based on cyan ink). Therefore, ink replacement is required twice to reproduce the required ink density. In this embodiment, the number of ink replacements is set to 3 or more in consideration of the margin.

  FIG. 4 is a diagram for explaining the pit-in ink supply of the ink jet cartridge when ink is injected using ink from the initial time as a comparative example of this embodiment.

  As shown in FIG. 4, ink is supplied from the liquid supply port 3 into the liquid storage chamber 2 by performing suction B from the air communication port 7 with a suction pump of 30 KPa or more. When the high pressure of the suction pump is applied directly, the surface tension of the ink cannot hold the ink on the surface of the gas-liquid separation member, and when the pit-in ink supply is repeated, the pore size of the fibrous structure of the gas-liquid separation member 5 Therefore, ink may permeate and ink leakage may occur.

The surface tension of the ink used in this example varies depending on the color, but the maximum is 40 mN / m, and the surface tension of pure water is 72.75 mN / m.
In the case of pure water, since the surface tension is larger than that of ink, the pure water does not permeate from the gas-liquid separation member even if suction is performed at a vacuum pressure of 67 KPa.

  Although the gas-liquid separation member 5 shown in FIG. 4 does not have an opening, since the gas-liquid separation member 5 is a porous member, gas easily passes and liquid does not pass. The principle is that a water repellent (perfluoroalkyl type) is applied to the liquid contact surface of the gas-liquid separation member so that the liquid is held on the surface of the gas-liquid separation member by the surface tension of the liquid and the liquid does not penetrate. ing. The gas-liquid separation member used in this embodiment is excellent in chemical resistance because it comes into contact with ink, and is a material in which the fibrous structure can have a high porosity in the balance between ink supply and suction pressure. In this example, PTFE having an average pore diameter of 0.33 μm was used. There are other materials for the gas-liquid separation member, such as polyimide and polypropylene, but high porosity is impossible because of high mechanical strength.

Sectional drawing of the inkjet cartridge which is Example 1 of this invention The figure for demonstrating the pit in ink supply of the inkjet cartridge which is Example 1 of this invention. The figure for demonstrating the ink replacement of the inkjet cartridge which is Example 1 of this invention. The figure for demonstrating the pit-in ink supply of the inkjet cartridge compared with Example 1 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge unit part 2 Liquid storage chamber 3 Liquid supply port 4 Cover plate member 5 Gas-liquid separation member 6 Ink holding member 7 Atmospheric communication port 8 Suction cap

Claims (6)

  A recording head having a liquid discharge port, a liquid storage chamber for storing the liquid supplied to the recording head, an ink holding member for generating a negative pressure in the liquid storage chamber to hold ink, and a part of the liquid storage chamber A liquid supply port connected to a main tank provided in the liquid storage chamber, a gas-liquid separation member communicating with the atmosphere provided in a part of the liquid storage chamber, and a gas communication port communicating with the atmosphere via the gas-liquid separation member; In the ink supply method of supplying ink from the main tank by sucking the liquid storage chamber at a negative pressure from the gas communication port to the ink jet cartridge having An ink supply method using a high liquid.   2. The ink supply method according to claim 1, wherein the negative suction pressure in the liquid storage chamber at the time of ink injection at the initial time is 30 KPa or more.   The ink supply method according to claim 2, wherein the liquid used for ink injection at the initial time has a surface tension of 40 mN / m or higher, which is higher than that of the ink.   4. The ink supply method according to claim 2, wherein the density of the ink holding member in the liquid storage chamber is 0.085 g / cubic centimeter or less.   The ink supply method according to claim 1, wherein the gas-liquid separation member is a porous member.   The ink supply method according to claim 1, wherein the gas-liquid separation member is treated to have water repellency.

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