Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-05-01
2001-09-18
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S015000
Reexamination Certificate
active
06290329
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a recording apparatus usable with office equipment or communication equipment such as a copying machine, a facsimile machine, a word processor, a personal computer or an office computer, more particularly to an ink jet recording apparatus wherein ink is discharged or ejected through an outlet to a recording medium to effect the recording.
In a color ink jet recording apparatus, one dot is printed for a monochromatic (yellow, magenta, cyan or black) picture element, whereas two dots are printed for a picture element in the case of mixed colors such as red, green or blue. A color image is formed on a recording material by the mixture of a single color dot print and a mixed color dots print.
In a conventional color ink jet recording apparatus, particular coated sheet is used as the recording material. As long as the particular coated sheet is used, the droplet of the color ink is such as to meet the spread of the ink on the particular sheet, and therefore, the ink is properly absorbed and fixed without any problem. This is because with the particular coated sheet, the degree of the spread is determined so as to meet the droplet discharged from the recording apparatus.
However, requiring the user to always use the particular coated sheet in a color ink jet recording apparatus, is not desirable because the coated sheet is more expensive than plain paper, because the coated sheet is more easily curled than the plain paper, because handwriting thereon is not easy and because the print is not excellent from the standpoint of durability against light. In addition, a particular one of the coated sheets are required to be used. In the recent monochromatic ink jet recording apparatus, the fixing property is significantly improved, and therefore, has been put into commercial use. In the case of the color ink jet recording apparatus, however, the fixing property of the mixed color print portion is not good because the color mixture print is provided by overlapping of the different color ink dots, and therefore, the quantity of the ink is twice as much as the monochromatic print for the same picture element.
On the other hand, the recording material is a transparent sheet for an overhead projector (OHP) which has a relatively low ink absorption rate, or plain paper having a relatively low ink absorption rate, the spread of the ink droplet shot on the recording material is small, with the result of a smaller dot printed. Therefore, the density of the record is relatively low. In addition, image density difference occurs between the monochromatic print (BK, Y, M or C) and a color mixed print (R, G or B). Particularly, the black print portion looks poor as compared with the other print portion.
The conventional recording apparatus of this type has been so designed to match the coated sheet having a relatively high spread rate. Therefore, the ink droplet is too small as for the recording material having the low ink absorption rate. Therefore, the density of the black print decreases.
Thus, when the color recording is carried out on the recording material having the low ink absorption rate, a monochromatic color picture element has a smaller ink spread, and therefore, has a smaller area factor with the result of the low image density.
Referring to
FIG. 7
, a case is shown in which black characters and color patterns such as graphs are printed in the black character print portion BP and a color print portion CP, respectively. The color print portion CP is generally recognized as pattern, and therefore, it is sufficient if the pattern can be recognized, even if the density is slightly low. However, as for the black character print portion BP, the characters have to be correctly recognized, and therefore, a sufficient print density is desired. This has not been completely accomplished in a conventional color ink jet recording apparatus.
Since a mixture of yellow, magenta and cyan colors represents black, three colors are enough theoretically. However, the black color provided by the mixture of the three colors is not clear. For this reason, a color recording apparatus generally uses an independent black color. In such a color ink jet recording apparatus, monochromatic documents are printed using only the black (BK) ink.
Usually, in an ink jet recording apparatus, droplets of the ink is discharged through a discharge outlet or outlets to the recording material, usually paper. Therefore, a droplet of the ink forms a circular dot on the recording material, and a character or an image is provided by gathering of such circular ink dots. The recording is carried out with the predetermined ink discharging frequency and with a predetermined scanning pitch. Therefore, even if the droplets are successively discharged, vacancies are provided between adjacent dots on the recording material, if they are seen microscopically. The vacancies may be a cause of the low image density, and particularly when a document is recorded with black ink, it is not desirable.
Accordingly, it is a principal object of the present invention to provide an ink jet recording method and apparatus wherein a high quality of the images can be produced on a recording material having a relatively low ink absorption rate.
It is another object of the present invention to provide an ink jet recording method and apparatus usable with a recording material having a relatively low ink absorption rate, and wherein the black print portion is not poor as compared with the color print portion, so that the high quality of the image is assured.
According to an aspect of,the present invention, there is provided a recording apparatus having a black ink recording head for discharging black ink onto a recording material and at least one single color non-black recording head for discharging non-black ink onto the recording material, comprising: a recording head driver for driving the recording heads to discharge the ink onto the recording material; and a controller for controlling said recording head driver so that a volume, per unit area of the recording material, of the black ink discharged from the blue ink recording head and deposited on a recording region of the recording material is larger than that of the non-black ink discharged from the non-black ink recording head and deposited on a recording region of the recording material.
According to another aspect of the present invention, there is provided a recording apparatus having a black ink recording head for discharging black ink onto a recording material and at least one single color non-black recording head for discharging non-black ink onto the recording material, comprising: a recording head driver for driving the recording heads to discharge the ink onto the recording material; and a controller for controlling said recording head driver to operate said black ink recording head through a number of recording steps which is larger than a number of recording steps by the non-black ink recording head.
According to a further aspect of the present invention, there is provided a color ink jet recording apparatus, wherein each of the recording heads has plural ink discharging outlets; said recording heads are juxtaposed on a carriage; said plural recording heads discharges cyan, magenta, yellow and black ink materials while the carriage is scanningly moving along the recording material to effect color recording on the material, comprising: head driver for driving the recording heads to discharge the associated color ink onto the recording material; and a controller for controlling said head driver so that the number of scanning movements of said black ink recording head is larger than the number of scanning movements of any one of cyan, magenta and yellow ink recording heads for mixed color recording.
According to a yet further aspect of the present invention, there is provided a recording apparatus, comprising: a black ink recording head for discharging black into onto a recording material; at least one single color non-black recor
Fukazawa Hideo
Kawaguchi Koichiro
Kurata Tetsuji
Shinoda Kazuhiko
Takemura Makoto
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nguyen Lamson D.
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