Abstract:
A photographic processing apparatus according to the present invention exposes photographic papers using a laser beam modulated based on image data and includes a laser beam emitting device. A changeover part changes the level of a driving signal to any one of a plurality of discrete levels according to a coloring characteristic of the photographic paper. The level of the driving signal determines the intensity of the laser beam outputted from the laser beam emitting device in a plurality of levels (for example, three levels consisting of a high level, a middle level and a low level). A filter is also provided to reduce the intensity of the laser beam outputted from the laser beam emitting device.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a photographic processing apparatus which exposes photographic papers using a laser beam modulated based on image data. 
     BACKGROUND OF THE INVENTION 
     Recently, a photographic processing apparatus which adopts a so-called digital exposure method has been popularly used. In such a digital exposure method, a photographic papers are exposed by light modulated based on digital image data. By adopting the digital exposure method, various types of image processes such as color correction, concentration correction and sharpening processing can be performed with the high degree of freedom and, at the same time, a rapid additional printing processing can be realized. Further, it is possible to obtain prints of high quality which are excellent in the reproducibility of color and concentration and resolution. 
     As one type of such a digital exposure method, there has been known a scanning exposure method which exposes the photographic papers with a modulated laser beam scanned using a polygon mirror or the like. In a current situation, however, the photographic processing apparatus adopting the scanning exposure method cannot change the intensity of the laser beam which are outputted in a stable manner from a laser beam emitting device and hence, the photographic processing apparatus can only cope with the photographic paper having specific coloring characteristics. Accordingly, when a photographic paper having coloring characteristics different from the specific coloring characteristics is used, the quality of images formed on the photographic papers is largely deteriorated. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a photographic processing apparatus which can properly expose a plurality of types of photographic papers having coloring characteristics different from each other in conformity with these coloring characteristics. 
     With respect to the photographic processing apparatus of the present invention, the photographic processing apparatus which exposes photographic papers using a laser beam modulated based on image data includes a laser beam emitting device and changeover means for changing over the intensity of a laser beam outputted from the laser beam emitting device in a plurality of levels. 
     According to this photographic processing apparatus, since the intensity of the laser beam can be changed over in a plurality of levels, it is possible to properly expose photographic papers which differ in color characteristics from each other and the number of types of paper is equal to the number of changeover levels of the intensity of the laser beam. Here, it is preferable that the changeover means is adjusted in advance such that the intensity of the laser beam outputted from the laser beam emitting device at respective levels exhibits a small and stable change rate with respect to an environmental factor such as temperature. 
     From a viewpoint of obtaining prints of high quality by stabilizing the intensity of laser beams, it is preferable that the photographic processing apparatus of the present invention is further provided with stabilizing means which is for stabilizing the intensity of the laser beam outputted from the laser beam emitting device. 
     It is preferable that the photographic processing apparatus of the present invention further includes a filter which is for reducing the intensity of the laser beam outputted from the laser beam emitting device and a filter control means which is for changing over a laser intensity reduction rate obtained by the filter in a plurality of levels. 
     The intensity of the laser beam depends not only on an input power to the laser beam emitting device but also on the environmental factors such as temperature and hence, in stabilizing the intensity of the laser beam using only one level, it has been necessary to frequently perform a complicated tuning process. To the contrary, by adopting the above-mentioned construction, it is possible to divide the respective intensities of the laser beams so that each laser beam is out putted from the laser beam emitting device into a plurality of levels using a filter. Accordingly, it is unnecessary to additionally perform the complicated tuning process for increasing the number of changeover levels of the intensity of the laser beam outputted from the laser beam emitting device. Thus, it is possible to properly expose a larger number of types of printing papers which differ in coloring characteristics 
     Further, it is preferable that the photographic processing apparatus of the present invention is configured such that changeover means changes over the intensity of the laser beam outputted from the laser beam emitting device at two to five levels. Due to such a construction, the number of changeover levels of the intensity of the laser beam is relatively small, that is, 2 to 5 and hence, the tuning operation of the laser beam emitting device can be reduced. 
     Other and further objects, features and advantages of the invention will appear more fully from the following description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view showing a schematic construction of a photographic processing apparatus according to one embodiment of the present invention; 
     FIG. 2 is a block diagram for explaining an exposure unit used in the photographic processing apparatus shown in FIG. 1; and 
     FIG. 3 is a graph showing the relationship between an output intensity of a laser beam outputted from a laser beam source and an environmental factor such as temperature in the photographic processing apparatus shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One preferred embodiment of the present invention is explained in conjunction with attached drawings. 
     FIG. 1 is a view showing a schematic construction of a photographic processing apparatus according to this embodiment. The photographic processing apparatus  10  shown in FIG. 1 is comprises a photographic processing apparatus adopting a digital scanning exposure method using a laser beam. The photographic processing apparatus  10  includes a scanner part  20 , a printer part  30 , a processor part  40  and a finish processing part  50 . Photographic papers  11  which are elongated and accommodated in paper magazines  31 ,  32  which will be explained later are transported to a cutter  34 , which will be described later, along a path  18  indicated by a chain line shown in FIG.  1 . Then, the photographic papers  11  which are cut to a given length along the widthwise direction using the cutter  34  are transported from the printer part  30  to the finish processing part  50  by way of the processor part  40  along the path  18 . 
     In the scanner part  20 , various types of processes such as reading processing of images recorded in respective frames of a film and a digital conversion of read image data are mainly performed. In the printer part  30 , exposure processing based on the digital image data is mainly applied to the photographic paper  11  made of photo sensitive material. In the processor part  40 , processes such as development, bleaching/fixing and stabilization are applied to the photographic paper  11  which has been already subjected to the exposure. In the finish processing part  50 , drying processing is applied to the photographic paper  11  on which images are visualized. Also the photographic papers are discharged from the processor part  40  and the photographic papers  11  which are discharged from a discharge opening  19  after drying are sorted for every order. 
     The scanner part  20  includes a film mounting unit  21  to which the film is mounted and a scanner light source unit  22  in which a light source which irradiates light to the film at the time of scanning is accommodated. Below the film mounting unit  21 , an image pick-up element such as a CCD image sensor (not shown in the drawing) for picking up the film image is arranged. Image signals outputted from the image pick-up element are subjected to digital conversion by an A/D converter not shown in the drawing and, thereafter, are supplied to a control unit  1  which will be explained later. 
     The printer part  30  includes: two paper magazines  31 ,  32  which respectively accommodate elongated rolled photographic papers  11  and are selectively used; an advancing unit  33  which pulls out the photographic paper  11  having a given width from the paper magazines  31 ,  32 ; the cutter  34  cuts the photographic paper  11  pulled out from the paper magazine  31 ,  32  into a desired length along the width direction corresponding to a print size; a printing unit  35  which prints given characters on a surface (back surface) of the photographic paper  11  on which a photosensitive emulsion layer is not formed; a chucker  36  which transports the photographic papers  11  cut in a desired length in parallel at two or three rows to a stage before the exposure position; an exposure unit  3  which applies the exposure processing to the photographic paper  11 ; a plurality of pairs of rollers  37  which transport the photographic paper  11 ; and motors  38 ,  39  which are for driving the plurality of pairs of rollers  37 . Were, to prevent the cut photographic paper  11  from falling, the plurality of pairs of rollers  37  are arranged at an interval which is shorter than the shortest length which is conceivable as an interval when the photographic papers  11  are cut. 
     The processor part  40  includes: processing vessels  41   a  to  41   f  for applying respective processes comprising development, breaching/fixing and stabilization to the photographic paper  11  supplied from the printer part  30 ; tanks  42   a  to  42   d  for collecting waste liquid from the processing liquid stored in the processing vessels  41   a  to  41   f  and for supplementing a fresh processing liquid to the processing vessels  41   a  to  41   f ; a plurality of pairs of rollers  43  for transporting the photographic papers  11 ; and motors (not shown in the drawing) for driving the plurality of pairs of rollers  43 . 
     The finish processing part  50  includes: a heater  51  for rapidly drying the photographic papers  11  discharged from the processor part  40 ; a belt conveyor  52  for transporting the photographic papers  11  discharged from the discharge opening  19  in the direction perpendicular to a paper surface of FIG. 1; a plurality of pairs of rollers  53  for transporting the photographic papers  11 ; and motors (not shown in the drawing) for driving the plurality of pairs of rollers  53 . Here, to prevent the cut photographic papers  11  from falling, in the same manner as the plurality of pairs of rollers  37 , the plurality of pairs of rollers  43  and  53  are also arranged at an interval which is shorter than the shortest length which is conceivable as an interval when the photographic papers  11  are cut. 
     Further, the photographic processing apparatus  10  shown in FIG. 1 includes the control unit  1  for controlling the operation of the photographic processing apparatus  10  and a display  23  which displays and notices various information on the photographic processing apparatus  10  to an operator. 
     Subsequently, the exposure unit  3  employed by the photographic processing apparatus  10  of this embodiment is explained. The exposure unit  3  is provided for performing the scanning exposure of the photographic papers  11  using laser beams of three different wavelengths respectively corresponding to three colors consisting of blue (B), green (G) and red (R). As shown in FIG. 2, the exposure unit  3 , in the inside of a casing thereof, houses three laser beam sources  61 . To simplify the explanation, only one laser beam source  61  is shown in FIG.  2 . The same goes for acousto-optic modulators  62 , lenses and the like  63  and laser intensity detectors  66 . 
     Laser beams irradiated from respective laser beam sources  61  are incident on the acousto-optic modulators (hereinafter referred to as “AOM”)  62  which constitute optic modulators of diffraction grating and which function as filters for lowering the intensity of laser beams. In response to control signals supplied from an AOM control part  72  of the control unit  1 , the AOM  62  modulates the laser beam irradiated from the laser beam sources  61  in conformity with image data supplied from the AOM control part  72 . The respective laserbeams (primary diffracted beams of AOMs  62 ) which are diffracted by the AOMs  62  and are modulated in conformity with the image data pass through the lenses and the like  63  consisting of a reflection mirror, an expander lens, a cylindrical lens, a dichroic mirror and the like and, thereafter, are incident on a polygon mirror  64  as one synthesized laser beam. 
     The polygon mirror  64  is constituted by arranging reflection mirrors on respective side surfaces of a regular hexagonal cylinder and is rotatable about an axis of the regular hexagonal cylinder at a fixed speed. One synthesized laser beam is scanned along with the rotation of the polygon mirror  64  such that the synthesized laser beam is reflected on the reflection mirror arranged on one side surface of the regular hexagonal cylinder. Further, an fθ lens  65  which is arranged between the polygon mirror  64  and the photographic paper  11  shrinks only a diameter in the sub scanning direction of the synthesized laser beam reflected on the polygon mirror  64  and, thereafter, focuses the synthesized laser beam on the photographic paper  11 . In this manner, by making the photosensitive emulsion surface of the photographic paper  11  subjected to the line exposure using the laser beam, a latent image of a desired image is formed. 
     Further, the laser beams irradiated from the respective laser beam sources  61  are also incident on the laser intensity detectors  66  which are arranged at a side opposite to the AOMs  62  with respect to the laser beam sources  61 . The laser beam intensity detectors  66  are optical detectors which include photo sensors, CCD sensors or the like and detect the intensities of respective laser beams of blue, green and red irradiated from the corresponding laser beam sources  61 . The detected intensities of the laser beams are supplied to a laser intensity changeover part  71  of the control unit  1 . 
     The laser beam intensity changeover part  71  generates driving signals respectively for three laser beam sources  61  based on the type of the photographic papers  11  which are accommodated in the paper magazine  31  or  32  and the laser intensity signals supplied from respective laser intensity detectors  66  and then supplies the driving signals to corresponding laser beam sources  61 . To be more specific, the laser intensity changeover part  72  outputs driving signals which are obtained by converting digital signals of  256  stages ranging from 0 to 255 into analog signals using a D/A converter (not shown in the drawing) disposed in the inside of the control unit  1 . 
     In the photographic processing apparatus  10  according to this embodiment, the driving signals generated by the laser intensity changeover part  71  are for changing over the intensity of laser beams irradiated from the laser beam sources  61  to three levels consisting of high level (H), middle level (M) and low level (L) in response to the type of exposed photographic paper  11 . The driving signals are also for stabilizing the output intensity of the laser beams at respective levels based on a feedback control using the laser intensities detected by the laser intensity detector  66 . 
     Three levels consisting of high level, middle level and low level are values relative to each other. These three levels are respectively adjusted such that when the laser intensity is at the high level, the photographic paper having the coloring characteristics which require the largest laser intensity can be properly exposed out of the commercially available photographic papers. When the laser intensity is at the middle level, the photographic paper having the coloring characteristics which require the intermediate laser intensity can be properly exposed out of the commercially available photographic papers. Further when the laser intensity is at the low level, the photographic paper having the coloring characteristics which require the relatively small laser intensity can be properly exposed out of the commercially available photographic papers. 
     Accordingly, when the photographic paper  11  to be exposed is the photographic paper having the coloring characteristics which require the relatively large intensity, the laser intensity changeover part  71  is controlled based on a feedback control using the laser intensities detected by the laser intensity detectors  66 . The laser intensity changeover part  71  generates the driving signal which sets the intensity of the laser beams outputted from respective laser beam sources  61  to the high level and, at the same time, stabilizes the output intensities of the laser beams dependent on an environmental factor such as temperature as much as possible at the high level by suppressing the change of the output intensities. A similar control is performed with respect to the case in which the intensity of the laser beams is set to the middle level and the case in which the intensity of the laser beams is set to the low level. In this manner, the driving signals outputted from the laser intensity changeover part  71  are not always fixed under the condition with which the same photographic papers  11  are used and are changed every second depending on the environmental factor. 
     FIG. 3 is a graph depicting the relationship between the output intensity of laser beams outputted from the laser beam sources  61  and the environmental factor such as temperature in the photographic processing apparatus  10  of the present invention. In FIG. 3, a curve  81  shows a portion of the relationship between the laser intensity and the environmental factor when the driving signal supplied to the laser beam sources  61  is set to a fixed value (for example, “255” of 255 stages) corresponding to the high level of the laser intensity. A curve  82  shows a portion of the relationship between the laser intensity and the environmental factor when the driving signal supplied to the laser beam sources  61  is set to a fixed value (for example, “150” of 255 stages) corresponding to the middle level of the laser intensity. A curve  83  shows a portion of the relationship between the laser intensity and the environmental factor when the driving signal supplied to the laser beam sources  61  is set to a fixed value (for example, “80” of 255 stages) corresponding to the low level of the laser intensity. As shown in FIG. 3, at any levels, the laser output intensity largely depends on the environmental factor such as temperature. 
     Here, when the laser beams of low level are outputted from the laser beam sources  61  in conformity with the curve  83 , assuming the environmental factor as T1, the laser output intensity irradiated from the laser beam sources  61  assumes S1. However, when the environmental factor is changed from T1 to T2, provided that the driving signal is held at a fixed value, the laser output intensity irradiated from the laser beam sources  61  is lowered to S2. Accordingly, in the photographic processing apparatus  10  of this embodiment, the laser output intensity S2 is detected by the laser intensity detector  66  and the laser intensity changeover part  71  performs the feedback control based on the detected value so as to change the magnitude of the driving signals such that the laser output intensity irradiated from the laser beam sources  61  recovers S1 again. For example, in the example shown in FIG. 3, the laser intensity changeover part  71  changes the magnitude of the driving signals such that the relationship between the laser intensity and the environmental factor is expressed by a curve  83 ′ (for example, from “80” to “81” in 255 stages). Due to such a control, the laser output intensity when the environmental factor is T 2  assumes S 1  which is equal to the laser output intensity when the environmental factor is T 1 . Accordingly, with respect to the photographic processing apparatus  10  of this embodiment, there is substantially no possibility that the quality of the image formed on the photographic paper  11  is degraded due to the change of the environmental factor. Here, the explanation has been made with respect to the case that the intensity of the laser beams is low, and the same control is performed with respect to the case in which the intensity of the laser beams is set to the high level and the case in which the laser beam intensities are set to the middle level. 
     In this manner, according to the photographic processing apparatus  10  of this embodiment, the intensity of the laser beams can be changed over to three levels consisting of the high level, the middle level, and the low level using the laser intensity changeover part  71  and hence, three kinds of photographic papers  11  which differ in the coloring characteristics from each other can be properly exposed. Further, according to the photographic processing apparatus  10  of this embodiment, since the intensity of the laser beams can be stabilized by performing the feedback control using the laser intensity detectors  66  and the laser intensity changeover part  71 , it is possible to obtain the prints of higher quality. 
     Further, with respect to the photographic processing apparatus  10  of this embodiment, when the photographic papers  11  which are to be preferably exposed with the laser intensity falling between the high level and the middle level are used, the AOM control part  72  reduces the intensity of the laser output of the high level to a desired value in response to a signal which expresses a type of photographic paper supplied to the AOM control part  72 . In the same manner, when the photographic papers  11  which are to be preferably exposed with the laser intensity falling between the middle level and the low level are used and when the photographic papers  11  which are to be preferably exposed with the laser intensity falling below the low level are used, the laser intensity is reduced to a value corresponding to the type of photographic paper  11  to be exposed by the AOM control part  72 . 
     Accordingly, in the photographic processing apparatus  10  of this embodiment, by changing over the laser intensity to the three levels consisting of the high level, the middle level and the low level and by changing the intensity reduction rate at the AOM  62  using the AOM control part  72 , it is possible to properly expose a large number of types of photographic papers  11  which differ in color characteristics from each other. 
     Further, to realize the above-mentioned control which maintains the laser intensity in a stable manner irrespective of the fluctuation of the environmental factor such as temperature, it is necessary to repeatedly perform the cumbersome tuning operation with respect to each level. However, since the photographic processing apparatus  10  of this embodiment is provided with the AOM control part  72  having the above-mentioned function, it is no longer necessary to additionally perform the cumbersome tuning operation for increasing the number of changeover levels of the intensity of the laser beams outputted from the laser beam sources  61 . Thus, it is possible to properly expose a larger number of types of photographic papers  11  which differ in coloring characteristics from each other. 
     Although the level intensity changeover part  71  in this embodiment changes over the intensity of the laser beams outputted from respective laser beam sources  61  to three levels consisting of the high level, the middle level and the low level, the intensity of the laser beams may be changed over at two levels consisting of the high level and the low level. It is also possible to use four or five levels. By suppressing the number of changeovers to a relatively small value, the tuning operation of the laser beam sources  61  can be reduced. 
     Although one preferred embodiment of the present invention has been explained heretofore, the present invention is not limited to the above-mentioned embodiment and various design modifications are conceivable within the scope of the claims. For example, although the laser output is stabilized by compensating for the fluctuation of the environmental factor using the drive signals outputted from the laser intensity changeover part  71  in the above-mentioned embodiment, the fluctuation of the environmental factor may be compensated by the laser intensity reduction rate at the AOM  62  in place of the driving signals. Further, by superposing the image data on the driving signals outputted from the laser intensity changeover part  71 , the laser may be directly modulated at the laser beam sources  61  in place of the laser modulation at the AOM  62 . Further, the intensity of the laser beams may be stabilized using a feed-forward control in place of the feedback control. Further, the levels set at the laser intensity changeover part  71  may be an arbitrary number of levels equal to or more than six levels.