The present invention relates to a packaging structure for packaging an inkjet head with ink or preserving liquid stored therein.
Generally, an inkjet head is shipped from a plant in a state being incorporated in a main body of an image-recording unit or the like. However, when an inkjet head itself has to be, for example, repaired or replaced with a new one, the inkjet head is sometimes transported in a state being removed from the unit. The inkjet head is provided with ink inlets for supplying ink directly or through an ink supply tube from ink sources. When the inkjet head is transported, the ink inlets are disconnected from the ink source or ink supply tube. Therefore, not only nozzles but the ink inlets are also opened, which allows the inside of the inkjet head to communicate with the outside.
Ordinarily, the inkjet head removed from the unit has been filled with ink therein. The remaining ink occasionally leaks out to the outside from the opening portion such as nozzles or ink inlets due to air expansion due to changes of ambient temperature and/or air pressure during the transportation (by land, sea, air cargo transportation or the like) resulting in a ambient pollution.
To prevent this, it is conceivable to cover to seal the nozzles and the ink inlets with a cap or the like. However, although the leakage to the outside can be prevented, the ink leaked out inside the cap stay therein. In the case of a color inkjet head, since a plurality of ink colors is mixed with each other inside the cap covering the nozzles, when the air pressure returns to an ordinary pressure, the color mixed ink is drawn back into the inside of the inkjet head causing a pollution inside the head with another color. As a result, there resides such a problem that, when the inkjet head is mounted again onto the unit and the ink is discharged, precise color recording cannot be obtained due to the color mixture.
Also, when the inside of the cap is polluted by the ink, or when a large amount of the ink leaks and flow out from the cap, hands of service person occasionally get dirty while exchanging the head, or surrounding electronic component parts are occasionally polluted.
It is known that the inkjet head is filled with a preserving liquid (an ink liquid without dye) before shipping the same from plant so that the ink can be introduced smoothly when a user uses the inkjet head for the first time. For example, a structure for preventing leakage of the preserving liquid during the transportation (refer to FIG. 1) is disclosed in Japanese Patent Application Laid-Open No. 10-272784. It is conceivable to apply the structure of preventing the liquid leakage to the above-mentioned ink leakage prevention during its transportation. The Japanese Patent Application Laid-Open No. 10-272784 employs such a structure that a rubber cap is attached to the nozzles in order to air-tightly cover the same while keeping a predetermined distance away from the openings of the nozzles; and a cylindrical member, which has a long path communicated with the atmosphere therein, is attached to the ink inlets. It is arranged so that, when the air pressure changes during the transportation, the preserving liquid is allowed to leak out from the ink inlets into the path communicated with the atmosphere so that the preserving liquid is held within the path communicated with the atmosphere; thereby the liquid is prevented from leaking out to the outside.