Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-02-19
2004-12-28
Nguyen, Lamson (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S014000, C347S019000
Reexamination Certificate
active
06834947
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink jet printing apparatus which forms letters and pictures by means of ejecting ink droplets onto a print medium.
The present invention also relates to an ink jet printing method. According to this method, dye containing color ink is ejected on the print medium so as to mix or react with colorless or light colored liquid (print quality improver liquid) which contains various compounds capable of rendering the dye in the ink insoluble, thereby producing a highly reliable print with improved water resistance, light resistance, or the like properties, or a high density image of high quality, which suffers little from feathering or color bleeding.
Further, the present invention relates to a color ink jet printing method for printing color images clearly and with high density. More specifically, it relates to a printing method in which a set of color inks, such as yellow (Y), magenta (M) and cyan (C), or green (G), red (R) and blue (B), is used in combination with black (Bk) ink.
The present invention is applicable to all of the apparatuses which use a print medium such as paper, fabric, leather, unwoven fabric, or the like, as well as metals. As for specific examples of such apparatuses, it is possible to list office equipment or industrial production equipment, such as printers, copying machines, or facsimiles.
The printing method based on the ink jet system is widely used in printers, copying machines, facsimiles, and the like since it is advantageous in that the operating noise is low, the running cost is low, its size can be easily reduced, or it can be easily converted to print color images.
However, in order to produce “highly reliable printed products” or “printed images of high quality” using the conventional ink jet printing method, it was necessary to use specific paper suitable for the purpose; in other words, it was necessary to use dedicated paper with an ink absorbing layer. In recent years, a method has been put to practical use, which accomplishes these objectives by means of improving the ink so that the desirable results can be obtained using “plain” paper used in large quantity in the printer or copying machines. However, the level of quality reachable using this method has been unsatisfactory.
As for the method in which the ink is modified to improve the water resistance of the image, a method has been known, in which the water resistance is given to the coloring material contained in the ink. The problem is that the ink used in this method is rendered difficult to re-dissolve in the water once the ink dries; therefore, it is liable to plug the nozzles of the printing head and also makes the performances of the plugged nozzles difficult to restore. Of course, these problems can be prevented, but the prevention requires a complicated structure.
Japanese Laid-Open Patent Application No. 84,992/1981 discloses a method, in which the print medium is coated in advance with a material capable of fixing the dye to the print medium. This method, however, requires the use of a specific print medium, and also, cannot prevent increases in the size and cost of the apparatus, since the material for fixing the dye has to be coated. Further, it is rather difficult to reliably coat the dye fixing material to a predetermined thickness.
Also, Japanese Laid-Open Patent Application No. 63,185/1989 discloses a technology for adhering to the print medium a type of colorless ink capable of rendering the dye insoluble, using an ink jet printing head. In this method, the dot diameter of the colorless ink is rendered larger than that of the dot diameter of the printing ink; therefore, even when the landing points of the printing inks and colorless ink are displaced from each other, a satisfactory print or image quality can be obtained.
However, this method also suffers from several shortcomings. This method ejects the colorless ink across the entire surface where the images are to be formed; therefore, a large amount of the colorless ink is consumed, and as a result, the running cost increases. Also, since more than the usual amount of ink is ejected onto the print medium, it takes a longer time to dry the ink, and also, the landing points of the inks are displaced from each other because of the cockling of the print medium, which occurs as the ink adhered to the print medium dries. In particular, when a color image is formed, the cockling, which leads to the misalignment of the landing points, greatly deteriorates the image quality. The patent application being discussed here does not disclose any method for optimizing the amount of the colorless ink to be adhered to the print medium, according to the type of the print medium. Further, the colorless ink is ejected even when the high quality is not required, for example, even when the recording is made in a draft mode; therefore, the colorless ink is wastefully consumed. Further, the liquid permeation into the print medium varies depending on environmental factors such as the ambient temperature or humidity; therefore, there are times when the dye insolubilizing colorless ink fails to mix or react ideally with the image producing ink, and as a result, the dye is not made insoluble.
Also, the liquid differently permeates the print medium, depending on the type of the print medium; therefore, there are times when the dye insolubilizing colorless ink fails to mix or react ideally with the image producing ink, and as a result, the dye is not made insoluble.
Therefore, this method suffers from another shortcoming. Namely, when the dye is not made insoluble, the feathering or bleeding occurs and degrades the print image. Here, “feathering” represents a phenomenon where the bleeding ink leaves on the print medium, a pattern of trails that looks like a feather, and “bleeding” is a phenomenon where the color inks mix with each other on the print medium after they are deposited thereon.
There have been disclosed a large number of conventional technologies which are intended to improve the fastness of the print. Japanese Laid Open Patent Application No. 24,486/1978 discloses a technology which improves the resistance of the dyed product against humidity. According to this technology, the dyed product is put through a process in which the dye in the dyed product is turned into lake so that it is firmly fixed.
Japanese Laid-Open Patent Application No. 43,733/1979 discloses a printing method, in which an ink jet printing system is used in conjunction with two or more ink components, which increase their film forming capacities as they make contact with each other under normal or heated condition; wherein those components are allowed to make contact with each other on the print medium so that a film capable of adhering firmly to the print medium is formed.
Japanese Laid-Open Patent Application No. 150,396/1980 also discloses a method in which an agent capable of forming the lake with the water soluble dye in a water based ink is applied after the ink jet printing.
In Japanese Laid-Open Patent Application No. 128,862/1983, an ink jet printing method is disclosed, in which it is anticipated where the image producing ink is deposited, and the image producing ink and the processing ink are deposited thereon in an overlapping manner. According to this method, the processing ink may be deposited before the image producing ink, or may be overlaid on the image producing ink deposited before the processing ink; or the image producing ink may be overlaid on the processing ink deposited before the image producing ink, and thus deposited image producing ink may be covered with the processing ink.
However, the problems that might have occurred through practical applications of these printing methods have not been disclosed in these journals which present these prior technologies.
Further, no method has been disclosed in these patent applications, in which when two or more inks of different color are used, the processing liquid (print quality improver liquid) is made to react with only the
Inui Toshiharu
Kato Masao
Kato Minako
Moriyama Jiro
Onishi Toshiyuki
Canon Kabushiki Kaisha
Do An H.
Fitzpatrick ,Cella, Harper & Scinto
Nguyen Lamson
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