Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-02-06
2004-06-29
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06755496
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink jet printing method and apparatus for effecting image formation on a print medium using ink.
In an ink jet printing apparatus, ink droplets ejected from a printing head carried on a printing apparatus are deposited on a print medium, and the ink is fixed and colored on the print medium, thus providing a print of the image. A color image printing is possible when a plurality of color inks, such as cyan, magenta, yellow and black inks are used. In an usual ink jet printing apparatus, a printing head is provided with a plurality of ejection outlet arrays corresponding to the respective colors of the ink. From the ejection outlet arrays, respective colors of inks are detected to provide a color image print.
In order to prevent bleeding of the image formed on the print medium, the ink having a relatively high perviousness relative to the print medium such as paper is often used for the color or chromatic ink. On the other hand, as for the black ink which is frequently used to form letter images, the ink having a relatively low perviousness is often used to provide clear ages of the letter images. This is because when the black ink having a high perviousness is deposited on the paper, the ink penetrates relatively quickly along the fibers of the paper, and therefore, the edges of the letter image may be non-smooth.
In such an ink jet printing apparatus using the black ink having the relatively low perviousness and the color ink having the relatively high perviousness, there is a liability of a problem that when the black ink and the color ink are contacted to each other on the print medium, the ink bleeding occurs at the boundary between the black ink and the color ink (this problem will hereinafter be called “black-color bleeding”.
FIG. 1
shows an example of ejection outlet array arrangement in a printing head which is designed for avoiding such a problem. The printing head PH shown in this Figure comprises an ejection outlet array Bkl for ejecting the black ink (Bk), and a plurality of ejection outlet arrays for ejected the cyan (C), the magenta (M) and the yellow (Y), respectively. The shown arrangement of the ejection outlet arrays is applicable to a printing head which completes printing on the print medium by repetition of the recording operation with reciprocal scanning in the main scan direction of the printing head and recognition of feeding the print medium (paper feeding operation), that is, a so-called serial type recording device. In the Figure, an arrow M indicates the main scan direction. In the case of bidirectional print in which the ink is ejected in both of the forward and backward movements of the print head, two arrays of each of cyan, magenta and yellow ejection outlets are provided symmetrically with respect to the print scanning direction, as indicated by reference characters C
1
, C
2
, M
1
, M
2
, Y
1
, Y
2
, in order to provide the same ejection orders of the color inks respective of the directions of the scanning.
When only a black image is to be printed, all of the ejection outlets for the black ink are used, but when a color image is to be printed, only the portion, indicated by “a” of the black ejection outlets is used, and as for the color ejection outlets, the portion indicated by “b” is used.
With this structure, the black image data are printed on the print medium by the scanning of the printing head in the horizontal direction (main-scanning) in the Figure, using only the ejection outlet array a, and thereafter, the print medium is fed through a distance an in the vertical direction (sub-scan, or paper feeding). In the next main-scanning of the printing head, the printing is effected by the color ejection outlet arrays b, by which the image printing is completed for 1 print region. When the color ejection outlet array b carries out the printing, the black ejection outlet array portion a prints the black part of the image for the next print region.
According to this method, the color ink is ejected onto the print medium in the print scanning subsequent to the scanning of ejecting the black ink onto the print medium. Therefore, as compared with the case in which the black ink and the color ink are simultaneously ejected onto the same print region in one print scanning, there is a time period in which the black ink penetrates into the print medium and fixes, prior to the ejection of the color ink. Therefore, this method is advantageous from the stern point of suppressing the occurrence of the black-color bleeding.
However, when the bi-directional print is effected using such a printing head, the black image is printed in the forward scanning, and then, the color ink image is printed in the subsequent backward scanning, for example. In this case, after the printing of the last part of the black image in the forward scanning, the color ink image printing after the paper feeding starts with this part (the final portion of the black image formation in the previous print scanning). For this reason, at either one of the left and right edges of the completed print, the time period from the printing of the black ink onto the print medium and the printing of the color ink thereonto (black-color time difference) is relatively short, and it is relatively long at the other edge. Where the black-color time difference is a small, the black-color bleeding tends to occur. In addition, the lower end of the color ink ejection ejection outlet array b and the upper end of the black ink ejection outlet array portion a (portion c in the Figure) are adjacent to each other in the sub-scan direction (paper feeding direction), and therefore, the color ink and the black ink having the different perviousness and the like are contacted to each other with the result of bleeding occurrence. Additionally, surfactant contained in the color ink, for example, might flow into the black ink with the result of lowering of the interface tension of the black ink, which leads to movement of the black ink. If this occurs, the image density at this portion decreases, does deteriorating the image quality.
SUMMARY OF THE INVENTION
FIG. 2
shows another example of arrangement of the ejection outlet array in which a spacing corresponding to the distance of one sheet feeding operation between the black ejection outlet array and the color ejection outlet array when the color images are formed. In this Figure, as for the black ejection outlet array, only the portion used for the color image formation is shown.
With this structure, the black ink is ejected onto the print medium from the black ejection outlet array in a forward scanning, for example. Then, the paper feeding is carried out, but in the subsequent backward scanning of printing, the ink is not ejected onto this position on the print medium. The paper feeding is further carried out, and in the next forward scanning, the color ink is printed onto this position, thus completing the printing of one printing region. In this system, there is a time difference corresponding to one print scanning from the black ink shot to the color ink shot. This is advantageous over the arrangement shown in
FIG. 1
from the standpoint of preventing the black-color bleeding. It is considered that at the left and right positions on the print medium, the black-color time differences are equal in one print region, and therefore, this arrangement is advantageous from the standpoint of preventing the deterioration of the image quality.
However, the inventors investigations have revealed a problem with the arrangement shown in
FIG. 2
, depending on the control of the recording operation.
For example, the black ink is printed on the print medium in the forward scanning, and thereafter, the sheet is fed, and then, the backward print scanning is carried out. To the region on the print medium to which the black ink has just been printed, the color ink is not printed, as described hereinbefore. However, if the color ejection outlet array prints the color ink to form image in another (adjacen
Chikuma Toshiyuki
Iwasaki Osamu
Nishikori Hitoshi
Otsuka Naoji
Sugimoto Hitoshi
Canon Kabushiki Kaisha
Dudding Alfred E
Fitzpatrick ,Cella, Harper & Scinto
Meier Stephen D.
LandOfFree
Ink jet printing apparatus and method with suppressed... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet printing apparatus and method with suppressed..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet printing apparatus and method with suppressed... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3364889