Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1999-11-09
2001-12-11
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S136000, C347S246000
Reexamination Certificate
active
06330016
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image recording apparatus and an image recording method, and more specifically to an image recording apparatus and an image recording method using a digital line-exposing device for exposure of a photosensitive material.
2. Description of the Related Art
Conventionally, when a PLZT (lead lanthanum zirconate titanate) head is used for exposure of a photosensitive material, there is a problem that an intensity of irradiation light from each shutter portion (optical outputting portion) of the PLZT head changes depending on an ON/OFF frequency of the shutter portion. In order to solve this problem, generally, an optical sensor is run widthwise of the PLZT head to perform scanning for measurement of the intensity of the irradiation light from each shutter portion, and correction to the intensity of the irradiation light (known as a shading correction) is performed periodically.
For example, according to a proposal in Japanese Patent Laid-Open No. 6-347923 made by the applicant of the present invention, when a timer has accumulated a predetermined amount of time, the photosensitive material is removed from an exposing portion, and the optical sensor is run to make the scan for measuring the irradiation light intensity of the PLZT head. Then, based on the measurements, a ratio of the measured irradiation light intensity to a norm value is obtained for each of the shutter portions of the PLZT head as a measured data, and an inverse of the measured data is obtained as a correction data. This correction data is multiplied by an amount of exposure, and a resulting product is used as a basis for determining a corrected exposure time.
However, according to the above proposal, although the irradiation light intensity can be corrected, an accurate detection and calculation of the irradiation light intensity must be performed for each shutter portion, spending about 20 minutes. This causes another problem of decreased processing capacity of the image recording apparatus due to a loss of time. Especially, when the proposal disclosed in Japanese Patent Laid-Open 6-347923 is used, the decrease in the processing capacity becomes more significant if the timer is set to a shorter accumulation time.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide an image recording apparatus and an image recording method capable of performing the correction to the irradiation light intensity without decreasing the processing capacity.
According to an aspect of the present invention, there is provided an image recording apparatus for recording an image in a photosensitive material, comprising: a recording head having a plurality of optical outputting portions, for an exposure of the photosensitive material; and an adjusting means for adjustment of an intensity of light irradiated from the recording head to the photosensitive material for the exposure, based on an exposure data already used in another exposure by the recording head.
According to another aspect of the present invention, there is provided an image recording method through an exposure of a photosensitive material by a recording head having a plurality of optical outputting portions, comprising an adjusting step of adjusting an intensity of light irradiated from the recording head to the photosensitive material for the exposure, based on an exposure data already used in another exposure by the recording head.
According to the present invention, the irradiation light intensity is adjusted based on an exposure data already used in another exposure. Therefore, differing from the convention, there is no need for providing a separate time for measuring the irradiation light intensity and correcting the exposure data, and thus it becomes possible to prevent the loss of time. As a result, the irradiation light intensity can be corrected without decreasing the processing capacity.
According to the present invention, preferably, when the irradiation light intensity is adjusted and if a photosensitive material is of a size of a print, an interval exposure data differing from an exposure data used in an exposure of an N-th photosensitive material is obtained. The recording head performs an interval exposure based on the interval exposure data, between the exposure of the N-th photosensitive material and an exposure of the N+1-th photosensitive material.
By adjusting the irradiation light intensity characteristics of the recording head as described above, it becomes possible to prevent the exposure of the N+1-th photosensitive material from being affected by the exposure of the N-th photosensitive material. Further, since the recording head is adjusted during the time between the exposures, the correction of the irradiation light intensity can be performed without a loss of time. Still further, since there is no photosensitive material placed right beneath the recording head between the exposures, the interval exposure does not expose any photosensitive material.
In should be noted here that according to the present invention, the term interval exposure refers to an exposure performed by the recording head between an exposure of an N-th photosensitive material and an exposure of an N+1-th photosensitive material. The term interval exposure data refers to an exposure data used in the interval exposure.
Further, preferably, the interval exposure data is an inversion of a gradient of the exposure data used in the exposure of the N-th photosensitive material. Even if the amount of exposure is not uniform in the N-th photosensitive material, the amount of light irradiation from each of the optical outputting portions of the recording head can be uniformed for the exposure of the N+1-th photosensitive material by performing the interval exposure based on the above interval exposure data before the exposure of the N+1-th photosensitive material. Therefore, the correction to the irradiation light intensity can be made even more effectively.
Otherwise, preferably, the interval exposure data is prepared by inverting a value representing presence or absence of optical output from each of the optical outputting portions in the exposure of the N-th photosensitive material. In this case, presence or absence of the optical output during the exposure of the N-th photosensitive material is checked for each of the optical outputting portions of the recording head. Then, the interval exposure data is prepared so that an optical output in the interval exposure will be reversed. More specifically, if there was not an optical output from the optical outputting portion in the exposure of the N-th photosensitive material, then the interval exposure data for this particular optical outputting portion will be such that there will be an optical output in the interval exposure. On the contrary, if there was an optical output from the optical outputting portion in the exposure of the N-th photosensitive material, then the interval exposure data for this particular optical outputting portion will be such that there will not be an optical output in the interval exposure. The interval exposure is performed based on the interval exposure data prepared in the above manner. In this way, the interval exposure data can be prepared easily depending on the presence or absence of the optical output in the exposure of the N-th photosensitive material.
According to the present invention, preferably, when the adjustment of the irradiation light intensity is performed, exposure data of a predetermined number of lines already used in an exposure by the recording head is maintained, and the correction to the exposure data for a next exposure is made based on the maintained exposure data. In this case, when the exposure is performed, the exposure data for the next exposure is corrected based on old exposure data already used in another exposure. Therefore, differing from the conventions, there is no need for providing a time separately for correcting the
Armstrong, Westerman, Hattori, McLeland & Naughton, LLP.
Le N.
Noritsu Koki Co., Ltd.
Pham Hai C.
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