Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1999-04-27
2002-08-20
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06435639
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording method and an ink jet recording apparatus.
2. Related Background Art
Because ink jet recording apparatuses which can perform recording on recording media such as paper, cloth, plastics and sheets for OHP enable a high-density and high-speed recording operation, they have been widely used and commercialized as information processing systems, for example, printers as output means for copiers, facsimile machines, teletypewriters, word processors and workstations, or handy or portable printers for personal computers, host computers, optical disk equipment, and video/visual equipment.
In general, such an ink jet recording apparatus mainly comprises a carriage on which a recording head unit consisting of a recording head and an ink tank is mounted, a means that transports a recording medium, and a control means for controlling them. In this configuration, recording can be performed on the recording medium by serially scanning the recording head in the direction (hereinafter referred to as main scanning direction) vertically intersecting the transport direction (hereinafter referred to as sub scanning direction) of the recording medium and discharging ink drops from a plurality of discharge outlets of the recording head during this scan. Then, when this one-line recording is terminated, the recording medium is intermittently transported only by a predetermined amount. Further, an ink jet recording apparatus having a recording head, in which a plurality of discharge outlets which discharge ink drops are aligned in the sub scanning direction, has also been developed, and this ink jet recording apparatus can perform recording of a width (normally, a width of the head) that corresponds to the number of discharge outlets in one scan.
Because the ink jet recording apparatus described above performs recording by discharging ink drops, its running cost is cheap and its operation is also quiet. Because the ink jet recording apparatus can perform recording for the width of the head in one scan, it also enables a high-speed recording operation and has been widely used.
Further, a color ink jet recording apparatus equipped with 3- or 4-color recording heads, in which discharge outlets are aligned in the sub scanning direction, is also put to practical use. This ink jet recording apparatus installs four types of recording heads and ink tanks which correspond to three primary colors of yellow (Y), magenta (M) and cyan (C) or the four colors including black (B) in addition to these three primary colors, and can form a full-color image by the conventional ink jet recording method. Furthermore, in recent years, an ink jet recording apparatus, in which recording heads, which also discharge a lower density ink than each ink in addition to Y, M and C, inks are also installed and which enable representation of a smoother graduation, has also been developed.
Thus, an ink jet recording apparatus in which the single unit is used to enable formation of both a full-color image and only a black image such as a character is becoming the mainstream.
Hereupon, when a color image is formed on plain paper by the ink jet recording method, because the prevention of an ink blot in the boundary region of each color of black, yellow, magenta, and cyan and the prevention of the high density and feathering of a black image are conflicting issues, it is very difficult to obtain a high-density image having no ink blot and feathering.
This is because ink is prevented from blotting in the boundary region of each color by using quick-drying ink of which permeation rate into a plain paper is fast when a color image is recorded on the plain paper by the ink jet recording method. However, when the quick-drying ink is used, a black image is low in its density and a colored image part other than the black image has low color development. Moreover, because the quick-drying ink is easy to permeate along a paper fiber, feathering is easy to generate. In particular, characters printed in black are conspicuous in feathering and become unclear characters short of sharpness as compared with those printed in other colors. As a result, the quality of an image deteriorates greatly on the whole.
Accordingly, to obtain a high quality image with density of a black image part that is high and which causes no feathering, a method is sometimes used in which much ink, the permeation of which into plain paper is comparatively slow, is applied to the same location. However, because this method is slow in the permeation of each ink into paper, it conversely generates a blot. In particular, in the boundary area between a black image part and a color image part, a blot in black ink and color ink is generated and the quality of an image deteriorates greatly.
To improve these defects, an ink jet recording method of installing a heater in a recording apparatus, accelerating the drying of ink, and obtaining a blot-free color image having high color development between colors is also put to practical use. However, because this method installs a heater capable of drying ink in the recording apparatus, the unit becomes larger and more expensive.
Then, as described in Japanese Patent Application Laid-open No. 3-146355, a method of performing no printing in the area along the boundary area between the black image part and color image part is proposed. However, this method has a defect that data to be printed may change when an image is formed.
Further, as described in the Japanese Patent Application Laid-open No. 4-158049, a method of performing recording by installing a plurality of color heads for color recording and a head for character recording and switching the plurality of color heads and the head for character recording based on recorded data is proposed. Because in this method the black ink of the head for color recording and the black ink of the head for character recording differ, if a black image recorded by the head for color recording and a black image recorded by the head for character recording coexist, a sense of incompatibility caused by the quality difference of both images is generated.
Furthermore, a method of preventing a blot in the boundary region between a black image part and a color image part is taken into consideration by overlappingly applying three-color ink of Y, M and C to form a black image without performing printing with black ink in a fixed black area along the boundary between the black image part and color image part. However, the black image formed by overlappingly applying the three-color ink of Y, M and C has worse color development than the black image formed with only normal black ink.
On the other hand, as described in the Japanese Patent Application Laid-open No. 56-84992 and the Japanese Patent Application Laid-open No. 64-63185, a method of preventing a blot and feathering using a fluid which insolubilizes dyes is also proposed. In other words, because the fluid that insolubilizes the dyes and ink are mixed and fused on a recording medium, the ink is not permeated into the recording medium and the blot and feathering can be prevented.
The ink jet recording method described in Japanese Patent Application Laid-open No. 56-84992 is used to coat recording paper with a material for previously fixing the dyes. However, when printing is performed by this method, specific recording paper must be used, and to coat it with the material for previously fixing the dyes, the unit becomes larger and more expensive. Further, it is difficult to evenly coat the recording paper with the aforementioned material at a predetermined film thickness.
Moreover, as described in the Japanese Patent Application Laid-open No. 64-63185, there is also a method of making the colorless ink that insolubilizes the dyes adhere on a recording medium by an ink jet recording head.
Because this method makes the dot diameter of aforementioned colorless ink larger than the dot diameter of the ink for an image, desired characteristics can be satisfied
Inui Toshiharu
Kanematsu Daigoro
Nakajima Yoshinori
Barlow John
Brooke Michael S
Canon Kabushiki Kaisha
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