Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Woven fabric – Including strand precoated with other than free metal or alloy
Reexamination Certificate
1998-08-12
2004-11-09
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Woven fabric
Including strand precoated with other than free metal or alloy
C442S333000, C442S401000, C442S414000, C428S394000, C347S086000, C347S087000
Reexamination Certificate
active
06815381
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fibrous material suitable for members used in contact with an ink, a fiber mass formed with the fibrous material, an ink tank containing the fiber mass therein, an ink-jet apparatus using the fiber mass as at least a part of its members with which an ink comes into contact, and a production process of the fibrous material.
2. Related Background Art
In ink tanks [including an ink tank portion of an ink-jet cartridge integrally formed together with an ink-jet head (recording head)] used in ink-jet (recording) apparatus, a member called an ink-absorbing member, which serves to absorb and hold an ink therein and supply the ink to a head as needed, is generally used. In one form of ink-jet cartridges and the like, in which an ink tank thereof is detachably installed in a cartridge, and the ink tank alone is replaced when an ink contained in the ink tank has been consumed, an ink-absorbing member having a joint function that strong capillary force is generated at a joint surface with a recording head to collect the ink within the ink tank there and supply it to the head, i.e., a joint member, may also be used at the same time in some cases.
As the ink-absorbing member accommodated in an ink chamber, a spongy member composed of, for example, a urethane polymer is known, while a member composed of, for example, polyethylene, polyethylene terephthal ate or the like is known as the joint member.
Since the ink-jet head has a precise structure and tends to cause ejection failure due to inclusion of dust, dirt and/or the like, it is also conducted to provide a filter at a proper position in an ink flow path in order to prevent the ejection failure.
As such ink-absorbing members (including joint members) or filters, those of various materials and forms are tried. As one of them, it is known that a fibrous material is molded at a predetermined density to attain an ink-absorbing function, joint function or filtering function making good use of spaces defined among fibers of the fibrous material.
In order to allow a molding from a fibrous material to function as an absorbing member for ink-jet inks, it is required that the ink can be effectively received by capillary force in spaces defined among fibers of the fibrous material when molded into the molding, and at the same time the spaces among the fibers are surely retained to hold the ink therein even after the ink has been charged, and that the ink can be smoothly supplied to an ink-jet head connected to the absorbing member when the pressure on the side of the head is reduced by ejection of the ink. For example, Japanese Patent Application Laid-Open No. 8-310011 discloses that a nonwoven fabric, in which a relationship between surface tension and electric conductivity satisfies a specified equation, is used as an ink-absorbing member. Japanese Patent Application Laid-Open No. 8-20115 discloses that arrangement of elastic fibers within an ink chamber of an ink tank is adjusted to surely retain spaces among the fibers, thereby allowing a molding composed of a fibrous material to function as an ink-absorbing member.
Further, a fibrous material itself requires that any component, which proves to be unfavorable to an ink itself and for the ejection of the ink from an inkjet head, is not dissolved out therefrom upon contact with the ink, or if any, its amount is reduced to an extent that such unfavorableness is not caused.
For example, Japanese Patent Application Laid-Open No. 4-348947 discloses that an ink-absorbing member composed of a urethane polymer is washed with a polar solvent in advance to dissolve and remove nonvolatile components, thereby holding down the amount of components dissolved out upon contact with an ink to at most 0.04% by weight based on the weight of the ink.
Japanese Patent Application Laid-Open No. 64-4350 has as its object the solution of a problem that additives such as metal salts of stearic acid dissolve out in an ink from a resin or synthetic rubber from which an ink tank for storing the ink is formed, and discloses the provisions of sodium ion concentration in an ink to be stored as a means for solving such a problem. However, this publication does not refer to an absorbing member for holding the ink, in particular, an absorbing member to which a fibrous material is applied, to say nothing of the production process of the fibrous material.
The present inventors have carried out an investigation in which a filamentous fibrous material of a polyolefin rein disclosed in Japanese Patent Application Laid-Open No. 8-20115 is changed to a multifilamentous fibrous material having higher productivity, or replaced by a staple fiber material, with a view toward more reducing the cost of ink-absorbing members used for ink tanks for inkjet. As a result, it has been found that the mere limitation of variation in the ratio of a surface tension to an electric conductivity before and after washing with water disclosed in Japanese Patent Application Laid-Open No. 8-310011 does not suffice materials for ink-absorbing members, and such a material may rather adversely affect printing performance in some cases.
The first cause thereof is that although attached substances which may be washed out with water have been removed from a fiber mass by washing, a part of such substances still remain in the fiber mass without being washed out. Namely, it has been found that the fact that “the ratio of the surface tension to the electric conductivity does not change even after washing” referred to in Japanese Patent Application Laid-Open No. 8-310011 is unsynonymous to the fact that “the attached substances are actually removed by washing”. That the attached substances remain has been clarified from the fact that there exists substances to be washed out or removed, when a fiber mass no longer undergoing a change in the ratio of the surface tension to the electric conductivity upon washing is washed out further upon dividing it into portions, which is proved by a measurement of weight change and an infrared spectroscopic spectrum analysis.
The second cause is that there are substances which cannot be removed with water and are dissolved out in an ink to adversely affect the suitability of the ink for inkjet. Namely, any treatment for removing the attached substances with water has its limit for meeting higher performance requirements even if various methods are adopted.
Further, a fibrous material itself is required not to release any component, which proves to be unfavorable to an ink itself and for the ejection of the ink from an ink-jet head, upon contact with the ink, or if any, to reduce its amount to an extent that such unfavorableness is not caused.
Japanese Patent Application Laid-Open No. 9-109410 discloses a forward contact angle necessary for a porous absorber used in the simplification and stabilization of filling of an ink into an ink-absorbing member, but neither describes nor suggests anything about an absorbing member obtained by molding fiber.
Besides, a further point to be considered includes a phenomenon described below.
Namely, there is a phenomenon that in a case where ejection energy is applied to an ink using an electrothermal converter, deposits may appear in a partial region within an ink ejection nozzle, which is distant from the electrothermal converter, not close to the electrothermal converter, in some cases, and wettability such as forward contact angle or backward contact angle with the ink in this region is different from surroundings, thereby causing deviation of an ejecting direction (slippage).
Fundamentally, the deposit is generally present in a trace amount (layer thickness of deposit: at most 1 im) and dissolved in inks, but may appear in some cases when a case where an ink-jet recording apparatus is left to stand in a dry environment or under conditions that the temperature is rapidly changed in a short period of time like in a heat cycle test is combined with a case where an ink droplet (at most 20 ng) having s
Hamasaki Yuji
Hayashi Hiroki
Hinami Jun
Sanada Mikio
Shimizu Eiichiro
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Guarriello John J.
Morris Terrel
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