Facsimile and static presentation processing – Static presentation processing – Detail of image placement or content
Reexamination Certificate
1999-11-24
2004-06-01
Garcia, Gabriel (Department: 2624)
Facsimile and static presentation processing
Static presentation processing
Detail of image placement or content
C358S003270
Reexamination Certificate
active
06744530
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing apparatus that carries out continuous printing, in which a large image is printed on a large-sized printing medium.
2. Description of the Related Art
The ink jet printer, which creates dots using a plurality of different color inks ejected from a plurality of nozzles provided on a print head and thereby records an image, has been proposed as an output device of a computer and widely used to print an image processed by the computer in a multi-color, multi-tone manner. This printer enables an image to be printed on a large-sized printing medium, such as a roll of machine glazed paper. Such printing procedure is hereinafter referred to as continuous printing. A large image may be printed on a printing medium of several ten meters, for example, a banner.
There is generally a restriction in quantity of image data processed at once by an application program. In the case of continuous printing, the application program accordingly supplies print data divided in a plurality of pages. In the case of standard printing, a certain margin is present between adjoining pages. The process of continuous printing removes the margin between the adjoining pages and thereby enables an integrated image to be printed while receiving image data divided into a plurality of pages.
The ink jet printer generally uses a print head, on which a large number of nozzles are arranged in a sub-scanning direction, in order to enhance the printing speed. There is a technique called the interlace process, which may be adopted in the ink jet printer with such a print head as one of the recording processes that improve the picture quality.
FIG. 16
shows an example of the interlace process. In the example of
FIG. 16
, three nozzles are arranged at a nozzle pitch of two dots. Circles in
FIG. 16
represent dots created by the respective nozzles. The tens digit in each encircled numeral represents a nozzle number that creates the dot, and the units digit represents the pass of main scan that records the dot. In this example, the 1
st
pass of the main scan creates dots on the respective raster lin the 2
nd
nozzle and the 3
rd
nozzle, whereas the 1
st
nozzle does not create any dots. After a sub-scan by 3 raster lines, the 2
nd
pass of the main scan is carried out to form raster lines with all the 1
st
through the 3
rd
nozzles. Subsequently the combination of the sub-scan by 3 raster lines with formation of raster lines by each pass of the main scan is repeated to complete an image. As clearly understood from the illustration, no raster line is actually formed with the 1
st
nozzle on the 1
st
pass of the main scan, because no raster line that adjoins to the phantom raster line formed with the 1
st
nozzle on the 1
st
pass of the main scan can be formed by the 2
nd
or any subsequent pass of the main scan.
The interlace process forms raster lines intermittently in the sub-scanning direction to record an image. The advantage of the interlace process is that variations of the nozzle pitch and the ink ejection properties can be dispersed on the resulting recorded image. Even when there are some variations in nozzle pitch and ink ejection properties, the interlace process relieves the adverse effects of these variations and improves the picture quality of the resulting recorded image.
FIG. 16
shows only an example in which each raster line is formed at a certain nozzle pitch by one pass of the main scan. The image may, however, be recorded according to the interlace process with various amounts of sub-scan, which depend upon the nozzle pitch, the number of nozzles, the number of repeated scans, and other factors.
The interlace process is also applicable to the continuous printing. There are, however, several phantom raster lines, which do not actually contribute to formation of a resulting image, both in an upper end and a lower end of a printing area by the interlace process as clearly shown in FIG.
16
. In the case of continuous printing, it is required to print an image without any margins set between each pair of adjoining pages. The presence of such phantom raster lines that do not contribute to formation of an image is accordingly not allowed in the continuous printing. When the continuous printing mode is selected, the conventional technique carries out an upper end process and a lower end process in both the upper end and the lower end of each page, in order to avoid the presence of the phantom raster lines that do not contribute to formation of an image. The upper end process and the lower end process perform the sub-scan by irregular feeding amounts, while recording raster lines as discussed below.
FIG. 17
shows a state of continuous printing by the conventional technique. In the example of
FIG. 17
, image data divided into N pages are printed in a predetermined area on an integral, continuous printing medium. The upper end process carried out in the upper end of each page and the lower end process carried out in the lower end of each page enable a resulting image to be recorded without any margins between each pair of adjoining pages.
FIG. 18
shows an example of the lower end process. In the example of
FIG. 18
, the print head has seven nozzles arranged at a nozzle pitch of four dots in the sub-scanning direction. Solid circles represent the positions of the respective nozzles, and encircles numerals represent the nozzle numbers. Broken circles are drawn to clarify the nozzle pitch. Each column, which starts from the left end of the drawing, represents the position of the print head in the sub-scanning direction on each pass of the main scan. Before the lower end process starts, the sub-scan by 7 raster lines is carried out after every pass of the main scan. The lower end process first carries out the sub-scan of 4 raster lines, then repeats the sub-scan of 3 raster lines four times, and subsequently carries out the minute sub-scan of 1 raster line four times. This variation in feeding amount of sub-scan enables an image to be recorded without any drop-out of raster lines up to an end raster line where the 7
th
nozzle is located on the last pass of the main scan as shown in FIG.
18
.
FIG. 19
shows an example of the upper end process. The symbols in
FIG. 19
have the same meanings as those of FIG.
18
. The upper end process first carries out the minute sub-scan of 1 raster line four times, then repeats the sub-scan of 3 raster lines four times, and subsequently carries out the sub-scan of 4 raster lines. On completion of the upper end process, the standard sub-scan, that is, the sub-scan by 7 raster lines, is carried out after every pass of the main scan. This variation in feeding amount of sub-scan enables an image to be recorded from a 1
st
raster line where the 1
st
nozzle is located on the 1
st
pass of the main scan as shown in FIG.
19
.
In the conventional technique of continuous printing, however, there is banding, that is, misalignment of the positions of dot creation, on the boundary between adjoining pages. As described previously, the continuous printing procedure by the conventional technique performs the lower end process to print an image to the lower-most end of each page, and subsequently carries out the sub-scan by a large feeding amount. After the sub-scan by a large feeding amount, the procedure continues printing the image on a next page. By way of example, after a recorded image on the first page is completed by carrying out the lower end process shown in
FIG. 18
, the sub-scan is carried out by a large feeding amount corresponding to the size of the whole print head. This enables the recording procedure to resume on a 1
st
raster line in a next page, which is located immediately below the image on the first page, according to the upper end process shown in FIG.
19
. In the example of
FIGS. 18 and 19
, the print head has seven nozzles arranged at the nozzle pitch of four dots, so that the sub-scan by 25 raster lines is carried out on the boundary between adjoining page
Kono Nobuyuki
Someno Masahiro
Garcia Gabriel
Seiko Epson Corporation
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