Photocopying – Projection printing and copying cameras – Illumination systems or details
Patent
1989-02-16
1990-05-08
Hix, L. T.
Photocopying
Projection printing and copying cameras
Illumination systems or details
355 70, G03B 2772
Patent
active
049242601
DESCRIPTION:
BRIEF SUMMARY
RELATED APPLICATION
This application is related to my copending application Ser. No. 315,897 filed Feb. 16, 1989.
TECHNICAL FIELD
The present invention relates to an image forming apparatus and more particularly to an exposure system of the image forming apparatus which is advantageously suited for forming an image on a light sensitive film.
BACKGROUND TECHNOLOGY
Heretofore, preparation of a slide used in connection with various lectures has been conducted in such a manner in which a 35-mm camera 101 is fixedly mounted on a stand 102, facing downwardly, wherein an original 105 is illuminated by light sources 103 such as flash lamps or the like supported on the stand 104 with photographing being carried out by releasing a shutter of the camera 101, as is shown in FIG. 6. In that case, operator is required to adjust the height of the camera in dependence on the size of the original 105 for the purpose of proper focussing. Besides, shutter speed and aperture value have to be determined in dependence on the species of the original 105, the type of the light source 103 and brightness thereof.
Such operation however requires skillfulness, and it was difficult to prepare a desirable slide unless operator has knowledge of the photographical technology.
With a view to eliminating the shortcomings of the prior art mentioned above to thereby provide an image forming apparatus capable of forming a clear image through simplified manipulation without requiring skillfulness, the applicant of this application has made a proposal disclosed in Patent Application No. SHO 62-95374.
This apparatus includes an original supporting stage, a light source for illuminating an original disposed on the stage, sensitive film holding means for holding detachably a light sensitive film at an image position, an imaging optical system for guiding light reflected from the original to the light sensitive surface of the abovementioned film, a shutter disposed in the imaging optical system for controlling the exposure of the light sensitive film switch means outputting a start signal for initiating the photographing on the light sensitive film, and an operation controller outputting control signals at least for the abovementioned light source and shutter.
The length of optical path extending from the abovementioned light source to the light sensitive film is previously determined. The operation controller mentioned above is characterized by such arrangement that it outputs sequentially a shutter opening signal for opening the shutter, lighting means for causing the light source to emit light a predetermined number of times and a shutter closing signal for closing the shutter.
However, the technique described above has been attended with a new problem that the image suffers from unevenness in density.
The present invention has been made in view of the background described above and contemplates as an object to eliminate unevenness in the density of the photographed image.
DISCLOSURE OF THE INVENTION
The gist of the present invention resides in that a plurality of flash lamps are lit sequentially with a quantity of light which gives rise to no unevenness in the exposure of film due to the influence of reciprocity law failure.
BRIEF EXPLANATION OF THE DRAWINGS
FIG. 1 is a view showing an external appearance of an image forming apparatus with which the present invention is concerned, FIG. 2 is a front view showing schematically an optical system portion of the same, FIG. 3 is a side view of the same, FIG. 4 is a view illustrating relationships between a surface of an original and amount of exposure as realized by an exposure control according to the present invention, FIG. 5 is a view showing relationships between lamp lighting sequences and transmission factor of a film, and FIG. 6 is a view illustrating pictorially a slide preparation mode known heretofore.
BEST MODE OF CARRYING OUT THE INVENTION
In the following, an exemplary embodiment of the present invention will be described on the basis of the drawings.
FIG. 1 shows an exte
REFERENCES:
patent: 4255046 (1981-03-01), Corona
patent: 4334767 (1982-06-01), Lehman
patent: 4551011 (1985-11-01), Yuasa et al.
L. J. Mason, "Aperture Control of Integrating Cavity Flash Lamp Exposure" Xerox Disclosure Journal, vol. 11, No. 2, Mar./Apr. 86, pp. 77-78.
H. M. Harris, "Adaptive Illumination Balancing System" Xerox Disclosure Journal, vol. 4, No. 6, Nov./Dec. 79, p. 787.
L. J. Mason, "Exposure Control with Multiple Flash Lamps" Xerox Disclosure Journal, vol. 10, No. 5, Sep./Oct. 89, pp. 295-296.
Corrigan Alfred E.
Hix L. T,.
Polaroid Corporation
Rutledge D.
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