Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1999-09-23
2001-09-11
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S098000, C347S096000, C347S084000, C347S085000
Reexamination Certificate
active
06286952
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a printing device capable of ejecting a liquid mixture composed, for example, of ink and a diluent toward a recording medium, and more particularly to an improvement in arrangement of nozzles.
2. Description of the Related Art
So-called on-demand-type ink jet printer is adapted to form print images on a recording medium such as paper or film by ejecting ink droplets through nozzles in response to recording signals supplied to the printer. Recently, the ink jet printer of such a on-demand type has been rapidly prevailed due to its compactness or low manufacturing cost.
U.S. Pat. No. 5,371,529 previously filed by the present applicant, discloses the printer of such an on-demand type in which a gradation of recorded images is achieved by mixing ink and a transparent solvent as diluent at adequate proportions with each other immediately before ejection thereof. In such a printer, a concentration of the print images can be varied every recording dot, so that the printer is advantageous for obtaining a high quality duplicate of natural images such as photographs.
The printer is of a so-called intermixing type in which ink and diluent are mixed together in an interior of the ejection nozzle.
Meanwhile, in the conventional intermixing type printing device, there has been a problem that undesired mixing of ink and diluent and, therefore, mutual diffusion proposed, in the afore-mentioned U.S. Pat. No. 5,371,529, the printer in which a one-way valve manufactured according to an electroforming method is disposed in a boundary region between ink and diluent so as to prevent occurrence of the mutual diffusion therebetween during the stand-by period.
However, it is often difficult to completely separate ink from diluent during the standby period only by the arrangement of such a one-way valve. In addition, The one-way valve has another problem that its manufacturing cost is high.
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of the afore-mentioned problems. It is therefore an object of the present invention to provide a printing device having a simple structure and capable of preventing the occurrence of undesired mixing of ink and diluent during a stand-by period of an ink ejection process whereby mixing of ink and diluent and ejection of a fluid mixture composed of the ink and the diluent can be carried out surely.
In a first aspect of the present invention, there is provided a printing device including an ejecting nozzle with a first discharge opening and a metering nozzle with a second discharge opening, which are provided separately from each other to feed two kinds of fluids through the first and second discharge openings, respectively, the two kinds of fluids being mixed together to form a fluid mixture to be ejected toward a recording medium, wherein a smallest distance d between a closest point on each of the respective first and second discharge openings of the metering and ejecting nozzles is in the range of 0≦d≦5 (SI) where SI stands for an opening area of the first discharge opening of the ejecting nozzle.
In a second aspect of the present invention, there is provided a printing device including an ejecting nozzle having a first discharge opening and a plurality of metering nozzles each having a second discharge opening, which are provided separately from each other to feed fluids through the first and second discharge openings, the fluids being mixed together to form a fluid mixture to be ejected toward a recording medium, wherein a minimum distance d between the first discharge opening of the ejecting nozzle and the second discharge opening of each of metering nozzles is in the range of 0≦d≦5· (SI) where SI stands for an opening area of the first discharge opening of the ejecting nozzle.
These and other objects, features and advantages of the present invention will become more apparently from the following detailed description when read in conjunction with the accompanying drawings and the appended claims.
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Ando Makoto
Kagami Toshiki
Kishima Koichiro
Nakayama Tetsuo
Barlow John
Bell Boyd & Lloyd LLC
Shah Manish
Siemens Aktiengesellschaft
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