Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Utility Patent
1998-10-14
2001-01-02
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Utility Patent
active
06168268
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid replenishing method in a liquid supplying mechanism capable of supplying a plurality of liquids of different kinds and to a liquid ejection recording apparatus for ejecting the liquids to effect recording by making use of the foregoing method. More particularly, the invention concerns a color ink jet recording apparatus of a type in which ink liquids reserved in main tanks are fed therefrom to be temporarily retained in corresponding sub-tanks, the ink liquids are supplied from the sub-tanks to corresponding printing heads, and a certain ink liquid, when used up in the associated sub-tank, is replenished from the main tank thereof to the sub-tank.
2. Related Background Art
The technology concerning the supply of liquid using liquid supply paths is in practical use in a variety of fields, and an example of the application is an ink jet recording apparatus as a liquid supplying apparatus for ejecting droplets of ink from a recording head to achieve recording on a recording medium.
The ink jet recording apparatus has advantages of capability of recording a high-quality image at high speed but with low noise and capability of readily obtaining a color image, and recently has also been applied as apparatus for recording in large sheet size or in large recording volume, for example, such as a poster output.
Since the ink jet recording apparatus performs recording by ejecting the ink, the ink consumed by ejection always has to be supplied to the recording head. A generally known ink supplying method to the recording head, particularly for apparatus with a large ink consumption, is a method in which a large-volume tank is provided in a form integral with the main body of recording apparatus, an ink flow path is constructed of a pipe such as a tube between the tank and a head cartridge, a mechanism for feeding the ink to the head cartridge is placed in the ink flow path, and this mechanism works to replenish the ink. A specific example of the mechanism for feeding the ink is a mechanism for sending the ink by flattening the tube like a tube pump.
In the ink jet recording apparatus using a large volume of ink as described above there are also demands for downsizing of apparatus and for achieving much higher gradation and quality at high speed.
The method described above, however, for example when adopted in the application using a plurality of recording liquids of different kinds, such as color recording, requires a mechanism for feeding the ink, such as the tube pump, for each color on an independent basis, and there is thus a possibility that the size of the supply units becomes large, particularly in the case of many colors being used, and in turn, the size of the overall recording apparatus becomes large.
In addition, the above-stated method allowed the ink to pass in the mechanisms and it was thus difficult to remove dust etc. with reliability. Particularly, in the application using small apertures of ejection ports for implementing high quality of image, there was a possibility that the dust was deposited in nozzles of the recording head to solidify, so as to cause clogging or the like, and it was thus necessary to provide an extra configuration such as a filter for removing the dust in order to avoid it.
The applicant of the present application filed Japanese Patent Application Laid-open No. 10-6521 to suggest a liquid supplying method and liquid supplying apparatus in which the mechanisms for feeding the ink are provided independent of the ink supply paths, thereby solving the issue about the removal of dust, and facilitating and ensuring the supply of liquid in the liquid supply paths.
The present invention has been accomplished as a result of further intensive and extensive research based on the above suggestion by the present inventor and an object of the invention is to provide a liquid replenishing method for readily and quickly replenishing the liquid to a liquid supplying mechanism provided with plural liquid supply paths.
Another object of the present invention is to provide a liquid ejection recording apparatus that realizes downsizing of the supply unit without the possibility of mixture of dust and that also achieves high-speed recording by shortening ink replenishing time in printing time in a long-term sense.
SUMMARY OF THE INVENTION
For accomplishing the above object, the liquid replenishing method of the present invention is a liquid replenishing method to a liquid supplying mechanism, said liquid supplying mechanism comprising three or more liquid supply paths, each liquid supply path having a sub-tank for temporarily retaining a liquid and for supplying the liquid by guiding the atmosphere thereinto, the liquid replenishing method comprising a step of preparing a plurality of negative pressure generating means, each for replenishing the sub-tank with a liquid, the number of negative pressure generating means being smaller than the number of liquid supply paths, a step of grouping the plurality of liquid supply paths into groups according to the number of negative pressure generating means, a step of establishing a hermetically closed space in a sub-tank with a greatest consumption of the liquid in each group, and a step of replenishing the liquid while depressurizing the inside of the sub-tank kept as the hermetically closed space, by the negative pressure generating means associated with each group.
A liquid ejection recording apparatus of the present invention is a liquid ejection recording apparatus capable of ejecting liquids of mutually different kinds, said liquid ejection recording apparatus having at least three liquid supply paths, each liquid supply path comprising a liquid ejection head for ejecting a liquid to effect recording, a main tank for reserving a liquid to be supplied to the liquid ejection head, and a sub-tank, provided between the liquid ejection head and the main tank, for temporarily retaining the liquid and for supplying the liquid to the head by guiding the atmosphere thereinto, the liquid ejection recording apparatus comprising a plurality of negative pressure generating means, each for depressurizing the inside of the sub-tank in order to replenish the liquid from the main tank to the sub-tank, the number of negative pressure generating means being smaller than the number of liquid supply paths, wherein each of the plurality of liquid supply paths comprises hermetically closing means for establishing a hermetically closed space in the sub-tank, the plurality of liquid supply paths are grouped into groups according to the number of negative pressure generating means, and a sub-tank with a greatest consumption of the liquid in each group is replenished with the liquid by the negative pressure generating means associated therewith.
In the present invention comprising the above, the liquid in each liquid supply path is supplied via a sub-tank to the downstream side. For replenishing the sub-tank with the liquid, the sub-tank is hermetically closed to the atmosphere and is depressurized by use of the negative pressure generating means provided in a path different from the liquid supply path, whereby the liquid is replenished from the upstream side of the liquid supply path into the sub-tank, thus implementing stable replenishment of liquid in spite of the simple structure of the liquid supply path.
In addition, the present invention permits the configuration for selecting a supply path with the greatest liquid consumption in each group, out of the plurality of liquid supply paths grouped corresponding to the negative pressure generating means, and for simultaneously replenishing the selected supply paths with the respective liquids by use of the negative pressure generating means corresponding thereto, thereby implementing efficient replenishment of liquid and decrease in the time necessary for replenishment of liquid.
At this time, particularly, the negative pressure generating means exhaust only the air in the sub-tanks, which can minimize l
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nghiem Michael
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