Measuring and testing – Liquid level or depth gauge
Reexamination Certificate
2002-07-10
2004-06-08
Williams, Hezron (Department: 2856)
Measuring and testing
Liquid level or depth gauge
C073S001730, C073S053040, C073S301000
Reexamination Certificate
active
06745626
ABSTRACT:
The present patent application claims priority from Japanese patent applications Nos. H. 11-139683 filed on May 20, 1999, H. 11-147538 filed on May 27, 1999 and H. 11-256522 filed on Sep. 10, 1999, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1
. Field of the Invention
The present invention relates to a liquid container equipped with a piezoelectric apparatus therein which detects the consumption state of liquid inside a liquid container which houses the liquid, by means of detecting change of the level of the acoustic impedance, especially detecting the change of the resonant frequency. More particularly, the present invention relates to the piezoelectric apparatus detecting ink consumption in an ink cartridge and a mounting module member thereof, which are provided in the ink cartridge for use with an ink-jet recording apparatus. The ink-jet recording apparatus performs the printing operation by discharging ink droplets from a nozzle opening, in a manner such that ink in a pressure generating chamber is compressed by a pressure generating means corresponding to printing data.
2. Description of the Related Art
An ink cartridge mounted on an ink-jet type recording apparatus is taken as an example of a liquid container and is described below. In general, an ink-jet recording apparatus comprises: a carriage equipped with an ink-jet type recording head comprised of a pressure generating means which compresses a pressure generating chamber and a nozzle opening which discharges the compressed ink from a nozzle opening in the form of ink droplets; and an ink tank which houses ink supplied to the recording head through a passage, and is structured such that the printing operation can be performed continuously. In general, the ink tank is structured as a cartridge that can be detached from the recording apparatus, so that a user can easily replace it at the time when the ink is used up.
Conventionally, as a method of controlling the ink consumption of the ink cartridge, a method is known of controlling the ink consumption by means of a calculation in which the counted number of ink droplets discharged by the recording head and the amount of ink sucked in a maintenance process of the printing head are integrated by software, and another method of controlling the ink consumption in which the time at which the ink is actually consumed is detected by directly mounting to the ink cartridge two electrodes for use in detecting the liquid surface, and so forth.
However, in the calculation-based method of controlling the ink consumption by integrating the discharged number of ink droplets and the amount of ink or the like by the software, the pressure inside the ink cartridge and the viscosity of the ink change depending on usage environment such as ambient temperature and humidity, elapsed time after an ink cartridge has been opened for use, and usage frequency at a user side. Thus, a problem is caused where a considerable error occurs between the calculated ink consumption and the actual ink consumption. Moreover, another problem is caused in which the actual amount of ink remaining is not known because once the same cartridge is removed and then mounted again, the integrated counted value is reset.
On the other hand, in the method of controlling by electrodes the time at which the ink is consumed, the remaining amount of ink can be controlled with high reliability since the actual ink consumption can be detected at one point. However, in order that the liquid surface of the ink can be detected, the ink need be conductive, so suitable types of ink for use are very limited. Moreover, a problem is caused in that a fluid-tight structure between the electrodes and the cartridge might be complicated. Moreover, since precious metal is usually used as the electrode material, which is highly conductive and erosive, manufacturing costs of the ink cartridge increases thereby. Moreover, since it is necessary to attach the two electrodes to two separate positions of the ink cartridge, the manufacturing process increases, thus causing a problem which increases the manufacturing costs.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a liquid detecting piezoelectric device capable of reliably detecting a liquid consumption status and dispensing with a complicated sealing structure. It is another object of the present invention to provide an ink cartridge capable of reliably detecting a liquid consumption status by use of a liquid detecting piezoelectric device and capable of dispensing with a complicated sealing structure. It is still another object of the present invention to provide a detection device capable of reliably detecting a liquid consumption status. It is still another object of the present invention to provide a mounting module for use in detecting liquid, capable of reliably detecting a liquid consumption status and capable of dispensing with a complicated sealing structure. It is still another object of the present invention to provide a liquid container capable of reliably detecting a liquid consumption status and capable of dispensing with a complicated sealing structure. These objects are achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention.
According to an aspect of the present invention, there is provided a piezoelectric device, mounted on a liquid container, for detecting a liquid consumption status of the liquid contained in the liquid container, comprising: a vibrating section which generates vibration by deforming a piezoelectric element, wherein the vibrating section is preferably symmetrical about a center thereof.
Moreover, it is preferable that the vibrating section of the piezoelectric device is of a substantially circular shape. Moreover, the piezoelectric device comprises: a piezoelectric layer; an upper electrode provided on an upper surface of the piezoelectric layer; a lower electrode provided on a lower surface of the piezoelectric layer; and a vibrating plate having a first surface contacting the lower electrode and a second surface a part of which contacting the liquid contained in the liquid container, wherein at least part of the piezoelectric layer, the lower electrode and the vibrating plate constitute the vibrating section. Moreover, it is preferable that respective main portions of the piezoelectric layer are approximately concentrically circular with the vibrating section.
Moreover, it is preferable that the piezoelectric device further comprises a base plate having an upper surface contacting the lower surface of the vibrating plate and a lower surface contacting the liquid contained in the liquid container. It is preferable that the base plate includes a cavity which contacts and holds the liquid contained in the liquid container. It is preferable that the cavity is approximately concentrically circular with the vibrating section. Moreover, it is preferable that the deformation of the vibrating plate due to a residual vibration is greater than that of the base plate. An edge of vibration of the vibrating section locates in the vicinity of an outer periphery of the cavity. It is preferable that the piezoelectric device further comprises a mounting member having an upper surface contacting the lower surface of the vibrating plate and a lower surface facing inside the liquid container, and the mounting member has an opening corresponding to a center of the vibrating section. Moreover, preferable is the liquid container mounting the above the piezoelectric device
According to another aspect of the present invention, it is preferable that a module comprises: the piezoelectric device; and a mounting structure formed integrally with the piezoelectric device for mounting the liquid detection device onto the liquid container.
The mounting structure may include a projected portion which is projected inward the liquid container, and a center of the vibrating section maybe arranged
Kanaya Munehide
Tsukada Kenji
Usui Minoru
Saint-Surin Jacques
Seiko Epson Corporation
Sughrue & Mion, PLLC
Williams Hezron
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