Photocopying – Projection printing and copying cameras – Tilting
Reexamination Certificate
1999-09-08
2001-09-18
Adams, Russell (Department: 2851)
Photocopying
Projection printing and copying cameras
Tilting
C355S029000, C355S035000, C355S041000, C355S044000, C355S067000, C355S049000, C250S216000, C358S444000, C358S501000, C358S515000
Reexamination Certificate
active
06292252
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an apparatus for producing a photographic picture or print especially a copy of image data of an original present in the electronic form and preferable through strip-wise projection of the image information of the original onto a photographic copy material. The image data are thereby produced by way of a scanner arrangement and subsequently processed in an image data processing arrangement in order to be converted into the electronic form which is required for the exposure.
BACKGROUND ART
Digital picture producing apparatus on photographic basis, so-called digital photographic printers, produce paper copies or copies by projecting the image information of the underlying original present in an electronically stored format onto photographic copy material. For example, the image information of the original can be picture by picture optically reproduced for each image by way of a digitally operable mirror matrix. Accordingly, an optical representation of the original can be produced and this optical representation of the original projected onto the copy material and thereby exposed thereonto.
With line by line or strip-wise projection using the micro mirrors of the mirror matrix any size photographic pictures can be theoretically produced in the direction transverse to the lines or strips. Respectively strip shaped portions of the original which in the longitudinal direction cover the whole original can be optically produced one behind the other by way of the mirror matrix and sequentially exposed in corresponding spatial orientation onto the copy material. The correct spatial positioning of the exposed strips is thereby achieved by displacement of the copy material relative to the exposure light path. This can be achieved by advancement of the copy material or by correspondingly movable projection optics. The relative displacement takes place synchronously with the change of the reproduced strips of the original. If the strips are several lines wide, adjacent strips can possibly also overlap. If the copy material depending on the degree of overlap is in some regions multiply exposed, this must be correspondingly taken into consideration for the adjustment of the amount of copier light used in the individual exposure steps. This exposure process is known under the acronym TIG (Time Integration Gray Scale).
Relatively satisfactory photographic prints can be produced with the above described methods and the use of a conventional micro mirror matrix. The manufacturing costs for such arrangements for the manufacturing of a photographic picture are relatively high and the speed with which these photographic pictures can be produced is often less than desirable, especially when the light intensity per surface area is small during the exposure so that long exposure times are required.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus which addresses the above disadvantages of the prior art.
According to the invention an apparatus for producing a photographic picture on a copy material is provided with a scanner in order to scan an original for obtaining image data for the manufacture of photographic pictures. Furthermore, an image data processing arrangement is present which can be used for the processing of the image data to control signals for the manufacture of the photographic picture. An exposure arrangement with projection optics for producing the photographic picture is connected to the image data processing arrangement. The exposure arrangement includes a mirror matrix with individually controllable mirrors. The exposure arrangement includes a preferably wide-band light source, for example a halogen light source, and a filter arrangement is positioned in the light path between the light source and the mirror matrix in order to especially adjust specific light amounts for specific spectral ranges.
While in the prior art often very costly light sources are used in the corresponding arrangements, and the light which is projected by the mirror matrix with the micro mirrors onto the photo-sensitive copy material is filtered, it has been surprisingly found that high light densities or light intensities can be achieved by way of a conventional, preferably wide-band light source, for example a halogen light source. The exposure by way of the individual colours of the light spectrum which are required for an appropriate exposure of certain image elements, can be adjusted with a corresponding filter for different colours and a corresponding activation of the micro mirrors of the mirror matrix.
The filter arrangement, for example in the form of a filter wheel can be equipped over its total circumference with several filter regions for each base colour in order to avoid down times or to increase the speed of the arrangement.
A transport arrangement for a light sensitive material is provided for the manufacture of the photographic picture in the exposure arrangement, whereby the transport speed of the light sensitive copy material is detected or monitored with the use of a sensor. The sensor can be in the shape of an optical scanning arrangement, a mechanical pick-up arrangement or the like in order to detect the actual transport speed of the copy material on the transport arrangement. Preferably, the measured transport speed of the photographic picture is used for the speed control in the transport arrangement and/or the exposure time or exposure intensity by way of the mirrors or the light source. This means that based on the actual control speed with which the copy material is moved, either the transport speed is adjusted, for example with a step motor within a control loop, or the exposure time is adjusted with the mirrors of the mirror matrix. Of course, as above noted, the intensity of the light source can also be changed by an additional darkening or brightening arrangement, for example in the form of a LCD which is shone through, or the like. Of course, the mentioned measures can also be combined within a control loop and not only individually used.
In order to monitor the light intensity of the light source both integrally as well as spectrally, a measurement sensor, for example a photo cell can be provided which carries out a measurement integrally or for individual colours for the light which is not used for the projection onto the photosensitive copy material. The output of the light source can be adjusted in this manner or it can be determined when the light source must be changed either automatically or manually. For the automatic exchange but also for the manual exchange can be provided, for example, a carousel, a sled or the like which is activated when the variables detected by the measurement sensor lie outside the tolerance. Otherwise, for example upon a reduction in the light output, initially more current or a higher voltage can be fed to the light source through a control loop in order to extend the period of use of the light source, for example a halogen lamp.
The filter arrangement can be constructed as a filter wheel, as an additive or subtractive colour filter, and the like.
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Fenner Jurg
Frick Beat
Adams Russell
Brown Khaled
Burns Doane , Swecker, Mathis LLP
Gretag Imaging AG
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