Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1998-11-23
2001-09-04
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S014000, C347S019000, C347S183000, C347S184000
Reexamination Certificate
active
06283570
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a printer apparatus.
With the development of electrical image equipment, image recording has been frequently carried out using an ink jet printer head or a thermoelectric printer head. In particular, the development of large-sized heads and multiheads is advancing for the purpose of high-speed printing.
However, in the case of printing, for example, in ink jet image printing, the amounts and the jet directions of inks jetted from respective nozzles of a printer head are scattered, and thus the scattering results in printing unevenness, such as a line to the eye. This printing unevenness becomes more conspicuous in larger-sized heads and multiheads. Thus, line-like unevenness arises periodically on a printed image at an interval of the width of the printer head. This results in a remarkable deterioration in image quality. There also arises a problem that in printing over a long period this unevenness changes with the passage of time.
U.S. Pat. No. 5,285,220 discloses a method for correcting such density unevenness.
Specifically, as shown in
FIG. 17
, a print image data is binarized in a binarization processing section
2
, and for printing with a printer head
3
, an unevenness correcting table
1
is arranged at the previous stage of the binarization processing section
2
. Using this unevenness correcting table
1
, the print image data is corrected. Correction of scattering in respective nozzles of the printing head makes it possible to correct density unevenness. Furthermore, considering the fact that density unevenness is different in accordance with the tone of image data to be printed even if the same nozzle is used, the correction corresponding to the tone of the image data is also carried out.
In the aforementioned U.S. Pat. No. 5,285,220, at the time of correcting each nozzle of the head, a density unevenness detecting chart is used to measure the tone characteristic of each of the nozzles, and a tone (gray level)-correcting characteristic for correcting this characteristic is memorized for each of the nozzles. In the case of, e.g., 8 bit data, however, the graduation has 256 tones and a considerably large memory capacity is necessary in order to memorize correction data for every tone for all of the nozzles. Moreover, much time is spent for detecting density unevenness using the density unevenness detecting chart of the 256 tones.
Therefore, an object of the present invention is to provide a printer apparatus that makes it possible to decrease a memory capacity for memorizing correction data necessary for correcting density unevenness and that cuts the down time for detecting the density unevenness.
BRIEF SUMMARY OF THE INVENTION
To attain the aforementioned object, a printer apparatus according to a first aspect of the present invention comprises:
a head having k (number) printing elements for printing an image data;
a printing element selecting section for selecting a printing element driven at the time of printing among the k printing elements of the head; and
an image data correcting section for correcting the image data previous to the printing of the image data using the head;
wherein the image data correcting section comprises:
a correction data memorizing section for memorizing a correction data for a certain single tone among n (number) tones that the image data has for each of the printing elements,
a tone detecting section for detecting the tone of the image data corresponding to each of the selected printing elements of the head, and
a correction data generating section for generating a correction data for each of the selected printing elements, corresponding to the tone detected by the tone detecting section, by using the correction data memorized in the correction data memorizing section.
Moreover, a printer apparatus according to a second aspect of the present invention:
a head having k (number) printing elements for printing an image data;
a printing element selecting section for selecting a printing element driven at the time of printing among the k printing elements of the head; and
an image data correcting section for correcting the image data previous to the printing of the image data using the head;
wherein the image data correcting section comprises:
a correction data memorizing section for memorizing correction data for correcting the image data for each of the printing elements, the number of the correction data corresponding to m (n>m) tones among the n tones that the image data has, and memorizing the total number m×k of the correction data for the k printing elements;
a tone detecting section for detecting the tone of the image data, corresponding to each of the selected printing elements; and
a reading section for reading the correction data corresponding to a tone detected in the tone detecting section from the correction data memorizing section, and for performing a correction operation to the image data.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 5285220 (1994-02-01), Suzuki et al.
patent: 5823690 (1998-10-01), Narushima et al.
patent: 5997123 (1999-12-01), Takekoshi et al.
patent: 6027196 (2000-02-01), Gotoh et al.
Jing Ganglu
Komiya Yasuhiro
Barlow John
Do An H.
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Olympus Optical Co,. Ltd.
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