1. Technical Field
The present invention relates to a liquid injecting method of injecting a liquid container suitable for an ink cartridge detachably mounted on, for example, an ink jet printer and the like, and the liquid container.
2. Related Art
As the ink cartridge (liquid container) detached from or attached to a liquid consuming apparatus such as the ink jet printer, there are suggested various kinds of ink cartridges of an open-air type that include an ink containing portion (liquid containing portion) for containing ink in a container body detachably mounted in a printer, an ink supply portion (liquid supply portion) for being connected to a printing head (liquid ejecting unit) of the printer, an ink guide passage (liquid guide passage) for guiding the ink contained in the ink containing portion to the ink supply portion, an air communicating passage for introducing open air into the ink containing portion from the outside with a consumption of the ink contained in the ink containing portion.
In such an ink cartridge, an ink residual quantity detecting mechanism (liquid detecting unit) in which a sensor having a piezoelectric vibrating body is disposed at a reference height in the liquid containing portion is provided (for example, see Patent Document 1). The liquid level of the ink stored in the liquid containing portion falls to the reference height with consumption by printing and outside air introduced from the air communicating passage to the liquid containing portion according to ink consumption reaches a detection position of the sensor. Then, the ink residual quantity detection mechanism outputs different signals between when the periphery of the sensor fills with an ink liquid and when the periphery of the sensor comes in contact with the air. The printer detects that the liquid level of the ink falls to the reference height based on the signals (change in residual vibration) output from the ink residual quantity detection mechanism.
That is, a change of acoustic impedance is detected by causing a piezoelectric device having a piezoelectric element or a vibrating portion of an actuator provided in the liquid containing portion to vibrate, subsequently by measuring a counter electromotive force generated by the residual vibration remaining in the vibrating portion, and by detecting an amplitude of a resonance frequency or a counter electromotive force waveform. The detected signal is used to display the residual quantity of ink or give notice of a cartridge replacement time.    Patent Document 1: JP-A-2001-146019
However, an ink cartridge is a container that includes multiple elements and is formed with a high precision. Accordingly, when ink is exhausted, the disuse of the ink cartridge results in a waste of a useful resource and a big economical loss. It is desirable that the used ink cartridge be re-used by re-injecting ink therein.
However, when the known ink cartridge is manufactured, an ink injecting step is included. Accordingly, after the ink cartridge is manufactured, there are many cases where the same ink injecting step cannot be used. As a result, it is necessary to develop a method of injecting ink in order to realize an ink-re-filling, instead of the ink injecting method at the time a new ink cartridge is manufactured.
A recent ink cartridge becomes high performance in that a differential pressure valve that adjusts an ink pressure to be supplied to the ink supply portion and also serves as a non-return valve for preventing the ink from flowing backward from an ink supply portion or an ink residual quantity mechanism for detecting an ink residual quantity is provided in an ink guide passage allowing an ink containing chamber to communicate with the ink supply portion. Moreover, a configuration of the ink containing chamber or an air communicating passage becomes complicated.
For this reason, when a container body is arranged carelessly and when ink is injected, a poor re-use may be caused. For example, the ink may leak into portions other than the ink containing portion or an original function may be damaged due to bubbles mixed when the ink is injected. For this reason, a re-use may be impossible.
In particular, when the bubbles floating in the injected ink are stuck to the surface of a sensor of the ink residual quantity detecting mechanism, the stuck bubbles may cause a change in residual vibration. Accordingly, it is not accurately detected whether there is the ink, and thus it may be erroneously detected that the liquid level of the ink falls.