Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-03-14
2003-12-23
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06666549
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is based on Japanese Patent Applications No. 2001-73848 and No. 2001-95696, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an ink-jet recording apparatus provided with main and auxiliary two ink tanks (a main tank and a subtank) for supplying ink to a recording head and its ink supply method.
An ink-jet recording apparatus is generally provided with a recording head mounted on a carriage and moved in a direction of the width of recording paper and a paper feed device for relatively moving recording paper in a direction perpendicular to a direction in which the recording head is moved.
In such an ink-jet recording apparatus, printing is performed on recording paper by jetting an ink droplet from a recording head based upon print data.
A recording head that can jet each ink in black, yellow, cyan and magenta is mounted on a carriage, not only the printing of text by black ink but full color printing are enabled by varying a rate of jettings of each ink.
Therefore, ink cartridges that supply each ink to the recording head are arranged in the main body of the recording apparatus.
In a normal ink-jet recording apparatus, each ink cartridge in which ink in one of black, yellow, cyan and magenta is stored is mounted on a carriage and is moved together with the carriage.
In the meantime, for example, in this type of recording apparatus provided for an office or for service, an ink cartridge having large capacity in which the above-mentioned each ink is stored is not arranged on a carriage and is arranged on the main body of the recording apparatus to correspond to a relatively large quantity of printing.
A recording apparatus of a type that a main tank as an ink cartridge is arranged on the main body of the recording apparatus (a cartridge holder) and a subtank is arranged on a carriage on which a recording head is mounted is also provided. Ink is supplied from each main tank to each subtank via an ink supply tube and further, ink is supplied from each subtank to each recording head.
In the latest recording apparatuses, to enhance a recording rate, a carriage is moved at high speed.
In such a recording apparatus, the pressure of inside ink varies by the extension or the bending of an ink supply tube due to the acceleration or the deceleration of the carriage and the jetting of an ink droplet from a recording head is made unstable.
Therefore, an open type ink supply method of opening a subtank to the air, discharging the above-mentioned varied pressure from the opening and supplying ink stored in the subtank to a recording head according to difference in an ink head is adopted.
However, the open type ink supply method has the following problems. That is, the open type ink supply method has a problem that as the subtank is open to the air, bubbles are included in ink in the subtank when ink is supplied, a degree of the deaeration of ink supplied to the recording head cannot be guaranteed and satisfactory printing cannot be realized.
There is also a problem that as ink is supplied from the subtank to the recording head according to difference in a head of ink in the subtank, the height of the subtank is required to be sufficiently secured and the whole subtank is large-sized.
SUMMARY OF THE INVENTION
The invention is made to solve such technical problems and the object is to provide an ink-jet recording apparatus as well as ink supplying method in which satisfactory printing can be realized and the whole subtank can be miniaturized.
The ink-jet recording apparatus according to the invention made to achieve the object is provided with a reciprocating carriage; a recording head mounted on the carriage for jetting an ink droplet corresponding to print data; a main tank for supplying ink to the recording head; and a subtank mounted on the carriage and connected to the main tank and the recording head, the subtank including an upper tank having an ink outlet for leading ink to the recording head, and a lower tank communicating with the upper tank and having an ink inlet for leading ink from the main tank by pressure of a pump, wherein the lower tank is elastically deformable according to variation of an internal pressure thereof.
As the ink-jet recording apparatus according to the invention is configured as described above, ink in the main tank flows into the lower tank of the subtank according to pressure of a pump when ink is supplied and after the ink further flows from the lower tank into the upper tank, it is supplied from the upper tank to the recording head.
At this time, when the variation of pressure occurs in the lower tank (in ink in an ink supply tube connecting the main tank and the subtank), the lower tank is elastically deformable according to the variation of the internal pressure (the volume) and the variation of the pressure (the volume) is absorbed.
Therefore, as ink from the main tank can be supplied to the recording head according to a closed type ink supply method, bubbles are not included in ink in the subtank when ink is supplied differently from heretofore, a degree of the deaeration of ink is guaranteed and satisfactory printing can be realized.
Also, as ink can be supplied from the subtank to the recording head by negative pressure provided on a side of the recording head, the height of the subtank can be reduced and the whole subtank can be miniaturized.
In this case, it is desirable that at least a part of a tank wall formed on the lower tank is made of an elastic film.
As the tank wall is configured as described above, a part of the tank wall is elastically deformable according to the variation of pressure in the lower tank when the pressure in the lower tank varies.
The elastic film is formed by a material which is flexible, resistant to ink and impermeable to moisture and gas.
As the elastic film is configured as described above, the subtank having the elastic film impermeable to moisture and gas and excellent in flexibility and resistance to ink can be acquired.
It is desirable that a check valve is arranged in the upper tank and opened by negative pressure provided on a side of the recording head.
As the check valve is configured as described above, negative pressure is generated on the side of the recording head, the check valve is opened and ink can be supplied from the main tank to the recording head via the subtank.
It is desirable that the ink jet recording apparatus is further provided with an ink amount detecting device detectable an ink amount in the subtank based upon an amount of elastic deformation thereof.
As the ink amount detecting device is configured as described above, an amount of the elastic deformation of the subtank is detected by the ink amount detecting device and the ink amount in the subtank is controlled.
Pneumatics generated by a pneumatic pump may be applied to the main tank so that ink is supplied to the main tank to the subtank.
As the ink-jet recording apparatus according to the invention is configured as described above, ink can be sequentially supplied from the main tank to the subtank, exceeding printing and the throughput can be enhanced.
A diaphragm pump may be provided at an intermediate position between the main tank and the subtank for supplying ink from the main tank to the subtank according to increase or decrease of an internal volume of the diaphragm pump.
As ink in the main tank is supplied to the subtank by the diaphragm pump when ink is supplied because of such configuration, the main tank is not required to be pressurized in case ink is supplied from the main tank to the subtank, and an ink pack that can resist pressurization and a mechanism for controlling pressurization are not required.
Therefore, as the number of controlled elements can be reduced, a control system can be simplified.
As a pressure chamber is not required to be formed in the main tank, the structure of the main tank can be simplified.
Further, as the outside dimension of the main tank is reduced beca
Harada Shuhei
Kobayashi Atsushi
Kumagai Toshio
Do An H.
Meier Stephen D.
Seiko Epson Corporation
Sughrue & Mion, PLLC
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