Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1998-06-19
2002-05-14
Yockey, David F. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C358S296000
Reexamination Certificate
active
06388698
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image recording apparatus having a recording head on which a plurality of recording sections are arranged dotted line-like in one or a plurality of rows; a moving means for relatively moving the recording head and an image recording medium; and a control means for controlling each recording section of the recording head so that one pixel is recorded by turning ON or turning OFF recording of the recording section in each of plural times (N times) of recording periods for each recording section of the recording head, the image recording apparatus records an image formed of a large number of pixels by the recording operation of each recording section of the recording head, on the image recording medium which is relatively moved by the moving means.
Conventionally, the following image recording apparatus is widely known: the image recording apparatus having a recording head on which a plurality of recording sections are arranged dotted line-like in one or a plurality of rows; a moving means for relatively moving the recording head and a photosensitive material; and a control means for controlling each light emitting section of the recording head so that one pixel is exposed by turning ON or turning OFF exposing in each of plural times (N times) of exposure periods for each light emitting section of the recording head, the image recording apparatus records an image formed of a large number of pixels by exposure of each light emitting section of the recording head, on the photosensitive material which is relatively moved by the moving means.
As one of these methods, it is considered and tested to record a multi-contrast image by an image recording apparatus in which the length T(m) of each exposure period satisfies the following equation with respect to the elapsed time sequence m (m is an integer not less than 0 and not more than N−1) of each exposure period in recording of each pixel,
T
(
m
)=&agr;×2
m
Where, &agr; is a coefficient of a positive real number independent of m.
When the above equation is satisfied, the elapsed time sequence of each exposure period becomes that arranged sequentially from a short exposure period to a long exposure period, as shown in FIG.
13
.
The control means controls each light emitting section of the recording head so that one pixel is recorded by turning ON or OFF the exposure in the m-th exposure period corresponding to the m-th digit data of multi-contrast image data expressed by a plurality of bits, in such a manner that, from multi-contrast image data expressed by a plurality of bits, 1 pixel is recorded by turning ON or OFF the exposure in the 0
th
exposure period corresponding to the 0
th
digit data; by turning ON or OFF the exposure in the 1
st
exposure period corresponding to the 1
st
digit data; by turning ON or OFF the exposure in the 2
nd
exposure period corresponding to the 2
nd
digit data, . . . , and an image is recorded by exposing pixels on the photosensitive material in the image recording apparatus.
However, in this image recording apparatus, it is known that, when an image, which is commonly called gradation in which density is monotonously increased or decreased in a predetermined direction, is exposed on the photosensitive material, a high density line or a low density line which does not originally exist in the gradation image, is generated during recording and becomes conspicuous.
To the inventor's surprise, not only the above description, but also the following is found: in an image recording apparatus having a recording head on which a plurality of recording sections are arranged dotted line-like in one or a plurality of rows; a moving means for relatively moving the recording head and an image recording medium; and a control means for controlling each recording section of the recording head so that one pixel is recorded by turning ON or turning OFF recording of the recording section in each of plural times (N times) of recording periods for each recording section of the recording head, the image recording apparatus records an image formed of a large number of pixels by the recording operation of each recording section of the recording head, on the image recording medium which is relatively moved by the moving means, when a gradation image is recorded on the image recording medium by an image recording apparatus in which the length T(m) of each recording period satisfies the following equation with respect to the elapsed time sequence m (m is an integer not less than 0 and not more than N−1) of each recording period in recording of each pixel, and in which the control means controls each light emitting section of the recording head so that one pixel is recorded by turning ON or OFF the recording in the m-th exposure period corresponding to the m-th digit data of multi-contrast image data expressed by a plurality of bits, in such a manner that, from multi-contrast image data expressed by a plurality of bits, 1 pixel is recorded by turning ON or OFF the recording in the 0
th
recording period corresponding to the 0
th
digit data; by turning ON or OFF the recording in the 1
st
recording period corresponding to the 1
st
digit data; by turning ON or OFF the recording in the 2
nd
recording period corresponding to the 2
nd
digit data, . . . , then, a high density line or a low density line which does not originally exist in the gradation image, is generated during recording and becomes conspicuous.
T
(
m
)=&agr;×2
m
Where, &agr; is a coefficient of a positive real number independent of m.
SUMMARY OF THE INVENTION
An object of the present invention is to prevent a high density line or low density line, which does not exist in a gradation image, from being generated even when the gradation image is recorded on the image recording medium.
As a theme of the present invention, a cause by which a high density line or a low density line which does not exist in the gradation image, is generated during recording and becomes conspicuous, is deeply considered, and as the result, the cause is considered as follows: the length T(m) of each recording period satisfies the following equation with respect to the elapsed time sequence m (m is an integer not less than 0 and not more than N−1) of each recording period in recording of each pixel,
T
(
m
)=&agr;×2
m
That is, for example, in the case where an image is recorded according to N-bit image data, when M is a natural number not more than N−1, in most cases, the elapsed time center of gravity of a recording operation of 1 pixel is scarcely changed between both image recording of pixels having the value different by only 1, in such a manner that the elapsed time center of gravity of a recording operation of 1 pixel is scarcely changed between the recording of the pixel having the value of 2
M
−2 and that of the pixel having the value of 2
M
−1, and the elapsed time center of gravity of a recording operation of 1 pixel is also scarcely changed between the recording of the pixel having the value of 2
M
and that of the pixel having the value of 2
M
+1. In contrast to that, the elapsed time center of gravity of a recording operation of 1 pixel is greatly changed between the recording of the pixel having the value of 2
M
−1 and that of the pixel having the value of 2
M
, as shown in FIG.
13
. Accordingly, the positional center of gravity of the recording operation of 1 pixel is greatly changed due to the relative movement of the recording head and the image recording medium during that time, as shown by a dashed line in FIG.
14
(A), and therefore, the positional center of gravity of a recorded amount of 1 pixel is greatly changed, as shown by a solid line in FIG.
14
(A).
Accordingly, it is considered that, when the gradation image is recorded on the image recording medium, although, as shown in
FIG. 14
, the positional center of gravity of the recorded amount is scarcely changed in most cases between adjoining pixels themselves
Deguchi Takashi
Hattori Tuyosi
Kawabe Toru
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Yockey David F.
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