JP4186755B2 - Laser exposure equipment - Google Patents

Description

  The present invention relates to a laser exposure apparatus capable of adjusting the amount of light using a light modulation element or the like, and in particular, exposes the surface of a photosensitive material using an exposure light source such as R, G, or B laser light, The present invention relates to a photographic processing apparatus for obtaining a color image.

  In recent years, a photographic processing apparatus that forms an image on a photosensitive material (printing paper) using image data captured by a digital camera, image data read by a scanner, or the like has been put into practical use. In such a photographic processing apparatus, for example, the intensity of a laser beam of each color such as R (red), G (green), and B (blue) is modulated, and a photosensitive surface of a photosensitive material using a polygon mirror, an fθ lens, or the like. Exposure is performed by scanning a laser beam in a direction (main scanning direction) perpendicular to the conveying direction. The exposed photosensitive material is developed and an image is formed on the photosensitive material (a photograph is printed).

  As is well known, there are various types of photosensitive materials depending on the manufacturer and application, and the sensitivity characteristics (coloring sensitivity characteristics) are different. Further, even in the same type of photosensitive material, the sensitivity characteristics vary depending on the usage environment, for example, temperature and humidity.

  Therefore, in the photographic processing apparatus, data indicating the relationship between the image pixel data (density gradation data) and the laser beam output gradation (hereinafter referred to as light modulation data) depending on the type of photosensitive material and the usage environment. A plurality of stored lookup tables are provided. The data in this look-up table is referred to when adjusting the intensity of the laser beam so as to obtain the same level of image density on the photosensitive material regardless of the type of photosensitive material and the usage environment.

  In an actual photographic processing apparatus, a laser beam having a substantially constant intensity emitted from a laser light source is transmitted through a light modulation element, and at this time, the amount of transmitted light of the laser beam is changed according to each gradation level of pixel data. Light modulation data corresponding to each gradation of the pixel data read from the lookup table is input to the driver of the light modulation element. Then, the driver drives the light modulation element with a drive signal corresponding to the level of the input light modulation data. As a result, a predetermined image is reproduced on the photosensitive material using light modulation data corresponding to each gradation of the pixel data of the image.

By the way, regarding the variation in the density of the image formed on the photosensitive material due to the variation in the photosensitive characteristics, for example, in Patent Document 1, the temperature of the photosensitive material or the vicinity of the irradiation position of the laser beam is measured by a predetermined temperature sensor or humidity sensor. By detecting the humidity and adjusting the output of the laser beam based on the temperature and humidity, the occurrence of variations in image density is prevented.
JP-A-6-183039

  In general, a photosensitive material includes a cyan layer (C layer) that develops color with respect to R light, a magenta layer (M layer) that develops color with respect to G light, and a yellow layer (Y layer that develops color with respect to B light). Layer), and these color development layers have sensitivity characteristics (spectral sensitivity) with respect to R, G, and B light, for example, as shown in FIG. Like the hatched area indicated by reference numeral 300, there are areas where the sensitivity characteristics (sensitivity characteristic curves) for each light overlap each other, and one of the three color development layers is affected by the overlap of the sensitivity characteristics. May develop colors and the other coloring layers may also develop colors. That is, for example, when R light is emitted to develop a cyan layer, the wavelength component of the R light is mixed into the magenta layer and / or the yellow layer, so that a cyan layer having R sensitivity characteristics develops color. Not only that, the magenta layer and / or the yellow layer will also develop some color (hereinafter, such color development is referred to as inappropriate color development). Furthermore, since the amount of color due to this inappropriate color development varies depending on the intensity of each R, G, and B light, the above-mentioned variation in image density cannot be corrected easily and accurately (patent) The technique of Document 1 does not disclose laser beam output adjustment in consideration of the effect of inappropriate color development).

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser exposure apparatus that can easily and accurately correct variations in image density of a photosensitive material.

According to the first aspect of the present invention, light of each color from at least two or more light sources each emitting light having a unique wavelength component is guided to the photosensitive material via the corresponding light modulation element. In the laser exposure apparatus for reproducing the density gradation data on the photosensitive material, the conversion data that associates the density gradation data with the light modulation data is used to obtain the target color development level. Conversion data storage means for storing each color as a reference characteristic, conversion data update means for updating the conversion data, and generation of a light modulation signal from density gradation data using the conversion data stored by the conversion data storage means A light modulation signal generation means for outputting the generated light modulation signal to the light modulation element; and a plurality of color reproduction signals using the light modulation signal output from the light modulation signal generation means. A test image forming means for forming a test image drawn on a photosensitive material; and a color development level of the test image formed on the photosensitive material; and a color development level of each color including at least a change in color sensitivity characteristics of the photosensitive material Measuring means for acquiring a change amount of the sensitometry, sensitometry creating means for obtaining, for each color, sensitometry indicating the relationship between the light modulation data and the color development level based on the color development level of the test image measured by the measurement means, and A specific wavelength component for the one color in the level change of the light modulation signal for one color of each color and the color change level of the photosensitive material by the other color accompanying the level change of the light modulation signal a change characteristic storage means for storing a variation characteristics showing the relationship between the change in inappropriate color level generated along with the possible but mixed for each color, each of the light modulation data If the color development level in the sensitometry is different from the density gradation data of the conversion data, the light modulation data necessary to correct the difference and shift the sensitometry to match the conversion data A main correction amount calculating means for calculating a main correction amount, and a bias value calculation for calculating a bias value necessary for further shifting the sensitometry reflecting an inappropriate color development level with respect to the main correction amount based on the change characteristic And the bias value calculation means calculates the inappropriate color development level for the main correction amount calculated by the main correction amount calculation means using the change characteristic stored in the change characteristic storage means. The main correction amount is further calculated using a level calculation means and the inappropriate color development level calculated by the inappropriate color development level calculation means. A correction main correction amount calculating means for obtaining a correction main correction amount to be corrected, wherein the conversion data updating means updates the conversion data based on the correction main correction amount .

The invention according to claim 2 is characterized in that the setting of the bias value, the calculation of the inappropriate color development level, and the calculation of the correction main correction amount are repeated until an error with respect to a predetermined color development level becomes a predetermined value or less. .

According to the first aspect of the present invention, the relationship between the light modulation data and the color development level is stored in the conversion data storage means as the sensitometry obtained by measuring the actual color development level and a reference characteristic. When different from the conversion data, the main correction amount calculation means calculates the main correction amount of the light modulation data necessary to correct the difference and shift the sensitometry to match the conversion data, The bias value calculation means calculates a corrected main correction amount that further corrects the main correction amount by reflecting an inappropriate color development amount with respect to the main correction amount. Then, the conversion data update unit updates the conversion data based on the correction main correction amount, and the light modulation signal generation unit generates a light modulation signal from the density gradation data using the updated conversion data. . Therefore, even if there is a variation in the photosensitive characteristics of the photosensitive material, the light modulation signal corresponding to the target color development level is automatically generated after reflecting the inappropriate color development amount. Can be easily and accurately corrected.

According to the second aspect of the present invention, the bias value calculation means repeats the setting of the bias value, the calculation of the inappropriate color level, and the calculation of the correction main correction amount until the error with respect to the predetermined color level becomes a predetermined value or less. . Therefore, since the light modulation signal corresponding to the target color development level is generated with higher accuracy, correction for variations in image density of the photosensitive material can be performed with higher accuracy.

  Hereinafter, a photo processing apparatus according to an embodiment of the present invention will be described as an example of a laser exposure apparatus according to the present invention. FIG. 1 is an overall configuration diagram of a photographic processing apparatus 10 according to an embodiment of a laser exposure apparatus of the present invention. The photographic processing apparatus 10 is a photographic printing paper based on image data obtained by taking a photographic image of each frame of a film with a scanner (not shown), or image data transferred from a computer described later. A laser exposure unit 100 that exposes the photosensitive material 1 to form a predetermined image on the photosensitive material 1 is provided. The laser exposure unit 100 is disposed at a position facing the exposure position 5X on the conveyor 5 that conveys the photosensitive material 1 in the interior 11B of the housing 11 of the photographic processing apparatus 10. The conveyor 5 includes a plurality of sets of driving rollers 5A, driven rollers 5B, guide rails 5C, and the like.

  Further, on the upper surface 11A of the housing 11, a plurality of magazines, for example, magazines 20A and 20B, each storing the photosensitive material 1 wound in a roll shape are provided. In order to detect the type of photosensitive material stored in the magazines 20A and 20B, two sets of sensors 21A and 21B are provided on the magazines 20A and 20B and the upper surface 11A of the housing 11, respectively. Further, on the upper surface 11A of the housing 11, a colorimeter 22 for reading a test chart 200 described later and measuring the density for each of R, G, and B colors (each light) is provided.

  The housing 11 and the magazines 20A and 20B are dark boxes, respectively, and the leading end portion 1B of the photosensitive material 1 is drawn out from the magazines 20A and 20B to the inside 11B of the housing 11, respectively. The photosensitive material 1 is cut into a predetermined size by a cutter 4 provided inside the housing 11B. Hereinafter, the photosensitive material 1 cut into a predetermined size is referred to as a photosensitive material piece 1A. The photosensitive material piece 1 </ b> A is conveyed from the exposure position 5 </ b> X to the developing unit 2 by the conveyor 5 in the interior 11 </ b> B of the housing 11.

  The developing unit 2 includes a plurality of tanks 2A, 2B, 2C, and 2D for storing a developing solution, a fixing solution, a bleaching solution, and a stabilizing solution, respectively. When the photosensitive material piece 1A exposed by the laser exposure unit 100 is conveyed through the developing unit 2, the latent image is developed, and an image is formed on the photosensitive surface of the photosensitive material piece 1A. The photosensitive material piece 1A on which the image is formed is dried by the drying unit 3 and discharged from the inside 11B of the housing 11. The discharged photosensitive material pieces 1A are stacked on a sorter 6 provided on the upper surface 11A of the housing 11.

  The photographic processing apparatus 10 includes a control unit 12, a monitor display 15 such as a CRT, a keyboard 16, a mouse 17, and the like provided in the housing 11, whereby a user inputs predetermined commands (commands) and data. Or information on development of the photosensitive material 1 can be confirmed. The monitor display 15, keyboard 16 and mouse 17 constitute an input / output unit 140. The input / output unit 140 may be provided separately from the housing 11 of the photo processing apparatus 10 or may be provided integrally with the housing 11.

  Here, the density measurement by the colorimeter 22 will be described. In the photographic processing apparatus 10, test exposure is performed on the photosensitive material piece 1 </ b> A in order to adjust the light amount of the laser beam emitted from the light source so as to be an appropriate light amount with respect to the photosensitive material 1. During the test exposure, a test chart 200 including a so-called gray gradation image (test image) drawn at a plurality of densities (color development levels) such as first to twentieth areas as shown in FIG. 13 is output (printed). The The gray gradation image of the test chart 200 is formed by irradiating the photosensitive material piece 1A with R, G, and B lights.

  The colorimeter 22 reads the output test chart 200 and detects the density (coloring level) of each of the first to twentieth areas from the gray gradation image obtained by the reading. However, the detection of the density in each of the first to twentieth regions is performed for each color of R, G, and B. For example, the density of the image in the tenth region is such that R is “0.75”, G is “0.85”, B is “0.80”, etc. Detection is performed. The colorimeter 22 is composed of, for example, an RGB sensor, and when detecting the density for each of the R, G, and B colors, the reflected light from the test chart 200 is converted to R, G using a predetermined filter. , B are separated into three colors (color separation).

  FIG. 2 is a diagram showing an example of the configuration of the laser exposure unit 100 in the photographic processing apparatus 10. The laser exposure unit 100 includes three laser light sources 104R, 104G that output laser beams of R, G, and B, which are three primary colors of light, each having a unique wavelength, in appropriate positions in a housing (not shown). 104B. The laser light source 104R is configured by a semiconductor laser (laser diode) that emits an R (red) laser beam having a wavelength of 680 nm, for example. The laser light source 104G includes a semiconductor laser and a second harmonic generator (SHG) (not shown) that converts a laser beam emitted from the semiconductor laser into a G (green) laser beam having a wavelength of 532 nm, for example. ing. Similarly to the laser light source 104G, the laser light source 104B is a semiconductor laser and a second harmonic generator (not shown) that converts a laser beam emitted from the semiconductor laser into, for example, a B (blue) laser beam having a wavelength of 473 nm. (SHG).

  The laser exposure unit 100 includes three sets of light modulation elements (hereinafter referred to as AOM) 106R, 106G, and 106B such as an acousto-optic modulator, and slit plates 108R, 108G, and 108B. 104R, 104G, and 104B are disposed on the optical path in front of them. In addition, mirrors 112R, 112G, 112B and 114 and a lens 116 are provided on the optical path in order to reflect the laser beams output from the laser light sources 104R, 104G and 104B in the direction of the polygon mirror 118.

  The mirror 112R is a total reflection mirror, and reflects the red laser beam output from the laser light source 104R to the mirror 112G side. The mirror 112G is a half mirror that transmits the red laser beam and reflects the green laser beam output from the laser light source 104G to the mirror 112B side. The mirror 112B is a half mirror that transmits the red laser beam and the green laser beam and reflects the blue laser beam output from the laser light source 104B to the mirror 114 side. With such a configuration, R, G, and B color laser beams are superimposed (combined).

  The polygon mirror 118 rotates at a constant speed, for example, in the direction indicated by the arrow A, and reflects the laser beam in a predetermined range. An fθ lens 120 is provided in front of the polygon mirror 118, and the polygon mirror 118 and the fθ lens 120 deflect the laser beam in the main scanning direction indicated by an arrow B. Since the photosensitive material piece 1A is conveyed in the direction perpendicular to the paper surface of FIG. 2 by the conveyor 5, the photosensitive surface is exposed by scanning with a light-modulated laser beam.

  On the exit side of the fθ lens 120 and on the upstream side in the main scanning direction B closest to the image exposure region, a mirror 131 for reflecting the laser beam toward the synchronization sensor 130 is provided. The synchronization sensor 130 is configured by a light receiving element such as a photodiode (PD), for example, and outputs a predetermined synchronization signal by receiving, for example, a red laser beam.

  The laser exposure unit 100 is set so that the intensity of each laser beam is constant. The intensity of each laser beam output from the laser light sources 104R, 104G, and 104B is modulated by the AOMs 106R, 106G, and 106B, respectively, according to the density gradations of the R, G, and B components included in the image data. The The laser exposure unit 100 includes a main control unit 101 including a CPU for controlling the overall operation of the laser exposure unit 100, and a first memory 102 including a RAM for temporarily storing various data. And a second memory 103 including a ROM storing a control program for the laser exposure unit 100 and the like. The main control unit 101, the first memory 102 and the second memory 103 are included in the control unit 12.

  The conveyor drive unit (CD) 50 and the polygon mirror drive unit (PMD) 51 are connected to the main control unit 101 for the conveyance control of the photosensitive material piece 1A by the conveyor 5 and the rotation control of the polygon mirror, respectively.

  The three laser driving units (LD) 105R, 105G, and 105B are connected between the main control unit 101 and the laser light sources 104R, 104G, and 104B, respectively, and laser beams output from the laser light sources 104R, 104G, and 104B. The strength is controlled to be constant.

  The three light modulation element driving units (MD) 107R, 107G, and 107B are connected between the main control unit 101 and the AOMs 106R, 106G, and 106B, and each of the R, G, and B color components included in the image data. It is a driver that controls to modulate the intensity of each laser beam passing through the AOMs 106R, 106G, and 106B in accordance with the light modulation data. The AOMs 106R, 106G, and 106B are configured by an acousto-optic element (not shown), an ultrasonic transducer, a light modulation element driving unit, and the like. When the ultrasonic transducer is driven by the drive signal supplied from the light modulation element driving unit, a periodic refractive index change that functions as a diffraction grating is generated inside the acoustooptic device. When the laser beam is incident on the AOMs 106R, 106G, and 106B, the laser beam is diffracted by Bragg reflection by the diffraction grating generated by the ultrasonic vibration, and is emitted as zero-order diffracted light and first-order diffracted light. Since the 0th-order diffracted light is shielded by the walls of the slit plates 108R, 108G, and 108B, it does not enter the mirrors 112R, 112G, and 112B. On the other hand, the first-order diffracted light passes through the slit plates 108R, 108G, and 108B, and then enters the mirrors 112R, 112G, and 112B.

  The first memory 102 includes lookup tables (hereinafter referred to as LUTs) 102R, 102G, and 102B, a bias information storage unit 1021, and a sensitometry storage unit 1022.

  The LUTs 102R, 102G, and 102B have a capacity capable of storing, for example, 12-bit data, and light modulation data (4096 gradations; 0) corresponding to pixel data (256 gradations; 0 to 255 gradations). (Output gradation of ˜4095 gradation), that is, an output value (light modulation data) for an input value (pixel data) input to each LUT. The LUTs 102R, 102G, and 102B store conversion characteristics indicating the correspondence between pixel data and light modulation data shown in FIG.

  The optical modulation data output from the LUTs 102R, 102G, and 102B with respect to the input pixel data is used to control the amplitude of the drive signal transmitted to the AOMs 106R, 106G, and 106B, that is, to modulate the laser beam by the AOMs 106R, 106G, and 106B. Used.

  The 0 to 4095 gradation of the light modulation data corresponds to a voltage in the range of 0 to 1 V, for example, that is, the voltage value is incremented by 1/4096 V from 0 gradation (0 V) to 4095 gradation (1 V). Is set to a high value. Each LUT outputs a signal having each voltage value (hereinafter referred to as a voltage signal) corresponding to each input pixel data, and this voltage signal is input to the MDs 107R, 107G, and 107B.

  Information relating to the setting of the light modulation data (output value) corresponding to the pixel data (input value) stored in the LUTs 102R, 102G, and 102B can be rewritten in response to a change in bias value to be described later.

  The bias information storage unit 1021 stores information on bias values for optical modulation data for R, G, and B light for performing output adjustment (power adjustment of each AOM) of the AOMs 106R, 106G, and 106B. . The bias information storage unit 1021 stores a predetermined value in a range of “0 to 99” corresponding to 0% to 100% as a bias value, assuming that the output of each AOM for each optical modulation data is 0 to 100%. . For example, when the bias value is “99”, the output of the AOM for certain optical modulation data is 100%, and when the bias value is “49”, the output is 50%. The bias information storage unit 1021 outputs a signal having information on the bias value (hereinafter referred to as a bias signal) to the MDs 107R, 107G, and 107B.

  The sensitometry storage unit 1022 includes sensitometry (sensitometry 73 shown in FIGS. 5 and 6) including information of an output characteristic curve, which will be described later, indicating the relationship between the light modulation data serving as a reference in performing test exposure and the image density of the photosensitive material 1. This information is stored.

  The second memory 103 includes a bias characteristic information storage unit 1031. The bias characteristic information storage unit 1031 stores bias characteristic information (FIGS. 7 to 9) described later.

  The image processing unit 150 performs predetermined image processing on the image data input via the input / output unit 140. The image data memory 151 temporarily stores image data of R, G, and B color components. The clock control unit 152 receives the synchronization signal from the synchronization sensor 130, reads the image data from the image data memory 151 by the image processing unit 150 based on the synchronization signal, and the image data to the MD 107R, 107G, and 107B. It controls the output timing.

  Here, output adjustment for each AOM using the light modulation data and the bias value will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of a signal path related to optical modulation by each AOM. Pixel data for R, G, B light is input from the image data memory 151 to the LUTs 102R, 102R, 102G, respectively. Each LUT outputs light modulation data corresponding to the input pixel data to the MDs 107R, 107G, and 107B as voltage signals corresponding to the light modulation data. On the other hand, information on bias values for R, G, and B lights output from the control unit 101 (calculated by a bias value calculation unit 1013 described later) is input to the bias information storage unit 1021. This input bias value is set (stored). Along with the output of the optical modulation data from each LUT to each MD, the bias value set in the bias information storage unit 1021 is output as a bias signal to the MDs 107R, 107G, and 107B.

  In each MD to which the light modulation data and the bias value are input, the bias values of the R, G, and B lights are superimposed on the light modulation data of each of the R, G, and B lights. A signal for adjusting the output of each AOM (hereinafter referred to as an optical modulation signal) that is shifted by the bias value and generated as a result is output to the AOMs 106R, 106G, and 106B. Each AOM performs light modulation of each laser beam emitted from the laser light sources 104R, 104G, and 104B and incident on each AOM based on each input light modulation signal.

  FIG. 4 is a block diagram illustrating a configuration of the main control unit 101 illustrated in FIGS. 2 and 3. The main control unit 101 includes a test chart output control unit 1011, a main correction amount calculation unit 1012, a bias value calculation unit 1013, an optical modulation data setting unit 1014, a change rate determination unit 1015, and an LUT update unit 1016.

  The test chart output control unit 1011 performs a test based on information stored in the LUTs 102R, 102G, and 102B and the bias information storage unit 1021 in response to an output instruction (test exposure execution instruction) of the test chart 200 from the input / output unit 140. The chart 200 is output.

  In the test chart output control unit 1011, information on a predetermined gradation value among 256 gradations for each region of the test chart 200, for example, “255”, “250” for each region of the first to twentieth regions. ”,“ 245 ”,...“ 0 ”are set. The test chart output control unit 1011 outputs the light modulation data information corresponding to the gradation value of each region for each of the R, G, and B lights from the LUTs 102R, 102G, and 102B to the MDs 107R, 107G, and 107B. The test chart 200 is printed by optical modulation of each AOM based on the modulation data.

  The main correction amount calculation unit 1012 changes the characteristic (hereinafter referred to as sensitometry) indicating the relationship between the light modulation data and the density of the photosensitive material 1 (photosensitive material piece 1A) for each of R, G, and B light. The main correction amount for each of the R, G, and B lights for correcting the change is calculated.

  Here, the main correction amount and sensitometry will be described with reference to FIG. FIG. 5 shows an example of the sensitometry. Sensitometry is created for each of the R, G, and B lights. A sensitometry 71 shown in FIG. 5 is for R light, and is an output characteristic curve 72 obtained by reading the test chart 200 by the colorimeter 22 and a reference read from the sensitometry storage unit 1021 (currently). And an output characteristic curve 73). The horizontal axis of the sensitometry 71 indicates light modulation data of 4096 gradations (log value; hereinafter, the log value indicates a common logarithm), and the vertical axis indicates the density of an image formed on the photosensitive material 1. However, this density is calculated from log (1 / T), for example, where the reflectance of light is “T”.

  The output characteristic curve 72 is a total of 20 points indicating the correspondence between the image density values of the first to twentieth areas in the test chart 200 and the values of the light modulation data used for image formation of the areas. Based on (interpolate 20 points).

  The output characteristic curve 73 has a predetermined reference density (for example, density “0.9”) with respect to a predetermined reference gradation (for example, 760 gradation) in 0 to 4095 gradations of the light modulation data. It is a characteristic curve (reference characteristic) serving as a reference for calculating the main correction amount. However, like the output characteristic curve 72, the output characteristic curve 73 is created by interpolation of 20 points obtained by reading the test chart 200 output at the previous test exposure.

  At the previous test exposure, the output characteristics indicated by the output characteristic curve 73 are changed because the sensitivity characteristics for the R, G, and B lights have changed due to changes in humidity and temperature with respect to the photosensitive material 1 (in this case, the sensitivity is Even if output is performed using the same light modulation data, a difference occurs in the image density formed on the photosensitive material 1. That is, as shown in FIG. 5, an output characteristic curve 73 including a point (reference point 74) having a density of “0.9” with respect to 760 gradations has a density of “0.8” with respect to 760 gradations, for example. The output characteristic curve 72 including a point (error point 75). Therefore, in order to eliminate the difference in the image density, first, the light modulation data is adjusted so as to obtain an output characteristic curve for obtaining the reference density with respect to the reference gradation. In this case, the light amounts of the R, G, and B lights are adjusted so that the error point 75 overlaps the reference point 74 (by moving the output characteristic curve 72 parallel to the output characteristic curve 73). The amount of change in the amount of light of each of the R, G, and B lights relating to this light amount adjustment indicates the main correction amount. Here, the main correction amount for the R light is a density difference “0.1” (density difference 76 in the figure) between the density “0.8” and the density “0.9” in the reference gradation. The amount of light change required for correction is shown.

  The main correction amount calculation unit 1012 includes a sensitometry creation unit 1017. As the test chart 200 is read by the colorimeter 22, the sensitometry creating unit 1017 generates output characteristic curves for the R, G, and B colors such as the output characteristic curve 72 based on information obtained by reading by the colorimeter 22. At the same time, an output characteristic curve that is a reference for correction such as the output characteristic curve 73 stored in the sensitometry storage unit 1021 is read to create sensitometry for each of R, G, and B colors such as sensitometry 71, and these output characteristic curves are created. By using this, a change in density (coloring level) of each of the R, G, and B colors of the photosensitive material 1 including at least a change in sensitivity characteristic of the photosensitive material 1 is acquired.

  Based on each sensitometry created by the sensitometry creating unit 1017, the main correction amount calculation unit 1012 changes the amount of light required for correcting the density difference 76 minutes based on, for example, the density difference 76 for each light of R, G, and B. Calculate the amount. However, the amount of change in light quantity is calculated on the assumption that inappropriate color development does not occur for each of the R, G, and B lights. When calculating the light amount change amount, predetermined conversion information (hereinafter referred to as light amount conversion information) for calculating the light amount change amount from the density difference 76 is used. This light quantity conversion information is preset in the main correction amount calculation unit 1012.

  A bias value calculation unit 1013 corrects the value of the main correction amount calculated by the main correction amount calculation unit 1012 in consideration of the influence of the inappropriate color development, and changes the amount of light corresponding to the corrected main correction amount. That is, a bias value for shifting the light modulation data by an amount corresponding to the reference density (color density level) of the photosensitive material 1 with respect to the reference gradation value in the light modulation data (the density difference of 76 minutes) is calculated. It is. The bias value calculation unit 1013 includes an inappropriate coloring light amount calculation unit 1018, a corrected main correction amount calculation unit 1019, and a convergence determination unit 1020.

  The unsuitable coloring light amount calculation unit 1018 changes (increases / decreases) the light amount of light of one of the R, G, and B colors (for example, R light) by the main correction amount or a corrected main correction amount described later. In this case, the amount of light corresponding to an inappropriate color for light of other colors (for example, light of G and B) is calculated. For example, the inappropriate color amount calculation unit 1019 increases the color amount (density) of the cyan layer by increasing the light amount of R irradiated to the cyan layer (color generation layer for R) of the photosensitive material 1 by the main correction amount. In this case, the amount of light corresponding to the unsuitable coloring amount of the magenta layer or yellow layer (hereinafter referred to as unsuitable coloring light amount) is calculated.

  The calculation of the unsuitable coloring light amount will be described with reference to FIGS. 7 to 9 show the level change of the light modulation signal with respect to a certain color light among the light of each color of R, G, and B, and other colors associated with the level change of the light modulation signal. Bias characteristics indicating the relationship between the color development level of the photosensitive material 1 due to the light of the above and the change in the inappropriate color development level that occurs when the unique wavelength component for the light of one color is mixed, that is, R, G 4B shows an example of a bias characteristic (change characteristic) showing a change in the amount of inappropriate coloring light with respect to the other two lights when the light quantity of a certain one of the B lights is changed. Information regarding the bias characteristics shown in FIGS. 7 to 9 (hereinafter referred to as bias characteristic information) is stored in the bias characteristic information storage unit 1031.

  7 shows changes in the unsuitable coloring light amounts of G and B when the R light amount is changed, and FIG. 8 shows changes in the inappropriate coloring light amounts of B and R when the G light amount is changed. Indicates changes in the unsuitable coloring light amounts of R and G when the B light amount is changed. 7 to 9, the horizontal axis indicates the bias value, and the vertical axis indicates the amount of light. (A) is a log-log diagram in which the horizontal axis and the vertical axis both indicate log values, and (b) It is a semilogarithm diagram in which the horizontal axis represents the linear value of the bias value, and the vertical axis represents the log value.

  Here, the calculation of the inappropriate coloring light amount with respect to the main correction amount of the R light will be described with reference to FIG. A characteristic line 81 shown in FIG. 7A indicates the amount of change in light amount when the bias value of the AOM 106R with respect to R light is changed. The characteristic lines 82 and 83 are light amounts corresponding to unsuitable color amounts for G and B light when the R light amount is changed according to the characteristic line 81 (when only the R light is applied to the photosensitive material 1). Hereinafter, the change in the amount of inappropriate color development) is shown. A point P1 is a base point of the light amount change and is an intersection of the characteristic lines 81 to 83. At the point P1, the light amount value is zero, and the bias value at the point P1 is the current bias value (obtained by light amount adjustment based on the previous test exposure) for the R light. The bias value at this point P1 is, for example, about 1.63, and this bias value “1.63” indicates “43” (43% output) as the linear value in FIG. By changing this bias value, the intensity (light quantity) of R light changes.

  Assume that the main correction amount calculation unit 1012 calculates the main correction amount for R light, for example, about 0.241 (+0.241; hereinafter, the plus sign is omitted). In this case, the amount corresponding to the main correction amount of 0.241 ", that is, the amount of light indicated by reference numeral 84 (the amount of light at point P1 (zero) on the characteristic line 81 to the amount of light at point P2 (0.241)). It is necessary to increase the amount of light R) by the amount corresponding to the distance up to.

  By the way, the point P11 is a point indicating the value of the horizontal axis of the point P2 (bias value “1.88”, light quantity zero), and the intersection of the straight line connecting the point P11 and the point P2 and the point characteristic lines 82 and 83. Are point P12 and point P13, respectively, the unsuitable coloring light amount of G light with respect to the light amount increase of “0.241” of R indicated by reference numeral 84 is the position from point P1 to point P2 on the characteristic line 81. The amount of light corresponding to the distance between the point P11 and the point P12, that is, the amount of light corresponding to the distance between the point P11 and the point P12 when it is considered that the point has moved from the point P1 on the characteristic line 82 to the point P12. Similarly, the unsuitable coloring light amount of the B light with respect to the light amount increase of “0.241” is a light amount corresponding to the distance between the points P11 and P13.

  Note that the bias value “1.88” at the point P2 in FIG. 7A corresponds to the bias value “75” at the point P2 in FIG. Also, the value of the inappropriate color intensity of the G light is about 0.039, and the value of the inappropriate color intensity of the B light is about 0.017. As described above, when the light amount is changed by the main correction amount “0.241” and the light amount of R irradiated to the cyan layer is increased, G and B corresponding to the unsuitable coloring amount of the magenta layer and the yellow layer are increased. Inappropriate coloring light amounts are “0.039” and “0.017”, respectively.

  Regarding the unsuitable coloring light amount of B and R with respect to the main correction amount of G, the main correction amount for G is about 0.186 by the main correction amount calculation unit 1012 as in the case of light amount correction for the main correction amount of R. If calculated, as shown in the bias characteristic of FIG. 8A, the amount of G light is changed from the position of the point Q1 (the same base point as the point P1) to the position of the point Q2, that is, by the amount of light indicated by reference numeral 85. Need to increase. With respect to the change in the amount of G light from point Q1 to point Q2, the unsuitable coloring light amounts of B and R are obtained as about 0.007 and about 0.011, respectively.

  Similarly, if the main correction amount calculation unit 1012 calculates the main correction amount of B as about 0.245 with respect to the R and G improperly colored light amounts with respect to the change in the light amount corresponding to the main correction amount of B, FIG. From the position of the point R1 (the same base point as the point P1) corresponding to the light quantity change amount “0.245” to the position of the point R2, that is, it is necessary to increase by the light quantity indicated by reference numeral 86. is there. The unsuitable coloring light amounts of R and G with respect to the change of the light amount of B from the point R1 to the point R2 are obtained as about -0.002 and about 0.025, respectively. The unsuitable color light amount for R has a minus (−) value. In the example of the bias characteristic shown in FIG. 9A, the light amount for R (unsuitable color light amount) decreases with an increase in the light amount of B light. (The characteristic line 87 of B has a negative slope).

  The bias characteristics used for calculating the unsuitable coloring light amount with respect to the main correction amount include not only those shown in FIGS. 7 to 9 but also a plurality of bias characteristics with different base point positions. That is, for example, in FIG. 7A, the position of the base point is the point P1 at which the currently set bias value “1.63” (the linear value in FIG. 7B indicates the bias value “43”). The amount of change of each light amount (main correction amount and inappropriate color light amount) from this base point is obtained. However, when the currently set bias value is not 1.63 but other values (for example, “1.60”, “1.61”, “1.62”, etc.) Another bias characteristic using the bias value of the other value as a base point is used.

  Information on a plurality of bias characteristics having base points different from the points P1, Q1, and R1 is stored in the bias characteristic information storage unit 1031 together with the bias characteristic information shown in FIGS. The bias characteristics shown in FIGS. 7 to 9 are set for the R, G, and B lights, although the base point position (point P1) has the same bias value “1.63”. And the same bias value is not necessarily required.

  The improper color light amount calculation unit 1018 calculates an improper color light amount with respect to the main correction amount calculated by the main correction amount calculation unit 1012 based on information such as bias characteristics shown in FIGS. Inappropriate coloring light amount (hereinafter referred to as corrected inadequate coloring light amount) with respect to the corrected main correction amount calculated by the amount calculation unit 1019 is calculated. The corrected inappropriate coloring light amount is a corrected inappropriate coloring light amount (R-gn, R-bn, G-bn, G-rn, B-rn, B-) obtained by correcting an inappropriate coloring light amount described later n times. gn).

  The correction main correction amount calculation unit 1019 corrects the value of the main correction amount calculated by the main correction amount calculation unit 1012 using the inappropriate color generation light amount (or correction inappropriate color generation light amount) calculated by the inappropriate color generation light amount calculation unit 1018. Thus, the corrected main correction amount is calculated. The calculation of the correction main correction amount will be described for the case of R light, for example.

  First, summarizing the calculation results of the unsuitable coloring light amount based on the bias characteristics shown in FIGS. 7 to 9, the main correction amount (light amount change amount) for R light is 0.241, and G for the R main correction amount is G. , B are inadequate amount of coloring light of 0.039 and 0.017, respectively. The main correction amount for the G light is 0.186, and the unsuitable amounts of light for B and R with respect to the G main correction amount are 0.007 and 0.011, respectively. Further, the main correction amount for B light is 0.245, and the unsuitable amounts of R and G coloring light for the B main correction amount are −0.002 and 0.025, respectively.

  Here, for convenience of explanation, symbols for the respective light quantities are set as follows. The main correction amount for R is R-r, and the unsuitable amounts of color for G and B with respect to the main correction amount for R are Gr and Br, respectively, the main correction amount for G is G-g, and the main correction for G B and R are unsuitably colored light amounts of Bg and Rg, respectively, B is a main correction amount of Bb, and R and G are unsuitable colored light amounts of R and G, respectively. Let b, Gb.

  The coloring layer (cyan layer) for R light may be colored not only by R light but also by G and B light. In this case, the amount of light affecting the coloring of the R coloring layer is: This is the sum of Rr, Rg, and Rb. That is, the R coloring layer is affected by a main correction amount of 0.241 and an inappropriate coloring light amount 0.009 obtained by adding 0.011 and −0.002. Therefore, the R coloring layer is irradiated with a light amount of 0.250, which is the total value of 0.241 and 0.009, that is, the density “0. As a result, an extra light of 0.009 light is emitted with respect to the main correction amount of 0.241 necessary for the correction from “8” to the density “0.9”. Will result in a high concentration. In other words, the amount of increase in the bias value for the AOM 106R is the light amount “0.232” obtained by subtracting the inappropriate color amount “0.009” from the main correction amount “0.241” (the corrected main correction amount “ 0.232 ") must be used.

  However, when the main correction amount is corrected from 0.241 to 0.232 in consideration of the unsuitable coloring light amount, the unsatisfactory coloring light amount of the G and B lights with respect to the corrected main correction amount “0.232” of the R light. The value of will also change. Similarly to the calculation of the unsuitable coloring light amount for the main correction amount “0.241”, the correction unsuitable coloring light amount for the G and B lights with respect to the R light correction main correction amount “0.232” is shown in FIG. Is calculated by the unsuitable coloring light amount calculation unit 1018. Similarly, the corrected improper coloring light amount for the G light correction main correction amount and the B light correction main correction amount are also calculated by the inappropriate coloring light amount calculation unit 1018 using the bias characteristics shown in FIGS. 8 and 9, respectively. The

  The corrected main correction amount calculation unit 1019 calculates a corrected main correction amount in which the main correction amount is further corrected by using the corrected inappropriate color light amount calculated by the inappropriate color light amount calculation unit 1018. Here, if the corrected main correction amount (0.232) obtained by correcting the R main correction amount (0.241) n times is represented by the symbol R-rn (n is an integer), this R-rn. G, B correction unsuitable coloring light quantities for G and B are G-rn and B-rn, respectively. Similarly, assuming that the corrected main correction amount obtained by correcting the G main correction amount n times is G-gn, the B and R correction improper coloring light amounts for the G-gn are B-gn and R-gn, respectively. Assuming that the corrected main correction amount obtained by correcting the B main correction amount n times is B-bn, the R and G correction improper coloring light amounts for this B-bn are R-bn and G-bn, respectively. Become. The corrected main correction amount calculation unit 1019 calculates R-rn, G-gn, and B-bn.

  In this way, in order to calculate the respective light amounts, the unsuitable coloring light amount calculation unit 1018 calculates the correction unsuitable coloring light amount from the correction main correction amount, and the correction main correction amount calculation unit 1019 newly calculates the correction main color from the correction unsuitable coloring light amount. An iterative calculation such as calculating the correction amount is performed.

  The amount of light affecting the color development of the R color layer is R-rn, R-gn and R-bn, and the amount of light affecting the color development of the G color layer is G-gn, G-bn and G-rn. In addition, the amount of light that affects the color development of the B color development layer is B-bn, B-rn, and B-gn.

  The convergence determination unit 1020 calculates a difference (total light amount error with respect to the main correction amount) between the main correction amount of each of the R, G, and B lights and the total light amount (total light amount) of the corrected main correction amount and the corrected inappropriate color light amount. By calculating and determining whether or not the difference value is equal to or less than a predetermined value, it is determined whether or not to end (converge) the repetitive calculation. For example, the convergence determination unit 1020 uses the correction main correction amount R-rn, the correction inappropriate coloring light amount R-gn, and the correction inappropriate coloring light amount R-bn in the R light, for example. It is determined whether or not the difference between the total light amount ((R−rn) + (R−gn) + (R−bn)) and the main correction amount R−r is equal to or less than a predetermined value (within an allowable range). Until the difference value becomes equal to or smaller than a predetermined value, the unsuitable coloring light amount calculation unit 1018 and the corrected main correction amount calculation unit 1019 repeatedly perform the calculation.

  Specifically, the predetermined value (allowable value) is set to 0.002, for example, and a correction main correction amount (for example, 0.270) and a correction inappropriate color light amount (for example, 0.029), which are the results of repeated calculation a predetermined number of times. ) Is 0.299 and the main correction amount is, for example, 0.300, the error with respect to the target 0.300 is 0.001 (= 0.300−0.299). Since this error satisfies the condition of the predetermined value “0.002” or less, the iterative calculation is terminated.

  Further, the convergence determination unit 1020 similarly determines an error for G and B light, and determines whether or not to continue the repeated calculation. The predetermined value (0.002) is stored in the convergence determination unit 1020 or the like as a preset value. However, this predetermined value is set for each light of R, G, and B, and may be the same value or different values. Hereinafter, the correction correction amount (for example, the correction correction amount “0.270”) determined after the completion of repeated calculation by the convergence determination by the convergence determination unit 1020 is referred to as a fixed main correction amount.

  As described above, the bias value calculation unit 1013 calculates the bias value for the determined main correction amount obtained by repeated calculation using the bias characteristics shown in FIGS. In FIG. 7A, when the main correction amount 0.241 for R light is corrected by repeated calculation, for example, the final correction amount is “0.200” (the light amount at the position of the point P3 in the characteristic line 81). The bias value (1.84) at the position of this point P3 becomes a value updated from the currently set bias value “1.63”. Similarly, the bias values for the determined main correction amounts of G and B light are calculated for the G and B light using the bias characteristics shown in FIGS. The bias value calculated for the fixed main correction amount may be a log value or a linear value.

  The light modulation data setting unit 1014 performs light amount adjustment for the main correction amount (determined main correction amount) so that the reference density (0.9) is obtained with respect to the reference gradation (760 gradation) of the light modulation data. In this case, the gradation value of the light modulation data corresponding to each density value other than the reference density is set.

  Here, the setting of the gradation value of the light modulation data will be described with reference to FIG. In FIG. 6, the output characteristic curve 77 obtained by correcting the output characteristic curve 72 shown in FIG. 5 overlaps the output characteristic curve 73 that is a reference characteristic regarding the density correction of the photosensitive material 1 with the reference point 74 as an intersection. This is a sensitometry 78 showing a state of being present. As shown in FIG. 6, when the output characteristic curve 77 and the output characteristic curve 73 are compared, the gradation value of the light modulation data with respect to the reference density (density “0.9”) is the same value (760 gradations). However, the gradation values of the light modulation data corresponding to the density values other than the reference density are different values. Therefore, the light modulation data setting unit 1014 corrects (sets) the gradation value of the light modulation data corresponding to each density value other than the reference density so that the output characteristic curve 77 matches the output characteristic curve 73.

  By the way, for each region of the test chart 200, a predetermined density value (hereinafter referred to as a target density value) which is a density target at the time of printing is determined. The light modulation data setting unit 1014 calculates the gradation value of the light modulation data with respect to the target density value using the output characteristic curve 77. In this case, for example, if the density “0.15” shown in FIG. 6 is the target density value of the second region in the test chart 200, for example, the density “0.15” is corrected before the light amount is corrected. The light modulation data (gradation value) indicated by reference numeral 79 is changed to the light modulation data indicated by reference numeral 80 for density “0.15” after correction. Similarly, the gradation value of the light modulation data for the target density values in the first to twentieth areas (20) of the test chart 200 is set. Then, 20 points indicating the relationship between the target density value and the gradation value of the light modulation data are interpolated to obtain an output characteristic curve 77, whereby light for density values other than the target density value in each region is obtained. The gradation value of the modulation data is set. Note that the target density value of any one of the areas of the test chart 200 may be set to the reference density “0.9”.

  The change rate determination unit 1015 calculates the change rate before and after the correction of the gradation value of the light modulation data with respect to the target density value in each region of the test chart 200, and the change rate of the gradation value of the light modulation data with respect to each region is calculated. It is determined whether or not to output a new test chart (test exposure) by determining whether or not it is equal to or greater than a predetermined value.

  For example, the gradation value of the light modulation data with respect to the target density value “0.15” (see FIG. 6) of, for example, the third region of the first to twentieth regions is determined by the current test exposure (light amount adjustment). Assuming that the gradation value of reference numeral 79 has changed to the gradation value of reference numeral 80, the change rate determination unit 1015 calculates the change rate of the gradation value of reference numeral 79 with respect to the gradation value of reference numeral 80. For example, the change rate when the gradation value of the light modulation data for a certain target density value is changed from 1000 to 1100 is calculated to be 10% from the calculation of {(1100−1000) / 1000} × 100. The

  When the change rate is equal to or greater than a predetermined value (for example, 5%), the change rate determination unit 1015 newly uses the light modulation data (gradation value) for each density value updated by the light modulation data setting unit 1014. Causes the test chart to be output. The predetermined value for determining the change rate is stored in advance in the change rate determining unit 1015. The change rate may be determined only for the target density value of each area of the test chart 200 as described above, or for other density values (over the entire density range). May be.

The LUT update unit 1016 performs pixel data (256 gradations) stored in the LUTs 102R, 102G, and 102B based on the gradation values of the light modulation data for the respective density values set by the light modulation data setting unit 1014. Each gradation value and each gradation value of the light modulation data corresponding to the pixel data are updated.

  FIG. 10 is a diagram illustrating an example of a conversion characteristic curve related to gradation conversion from pixel data (input gradation) to light modulation data (output gradation). The horizontal axis in FIG. 10 indicates pixel data in the gray-scale range (255 to 0 gradation) from white to black, and the vertical axis indicates light modulation data in the 0 to 4095 gradation. A point denoted by reference numeral 91 is a fixed point that is not changed before and after the correction corresponding to the reference density “0.9” with respect to the reference gradation 760. Each point on the characteristic curve indicated by reference numeral 92 is 20 points corresponding to the first to twentieth regions of the test chart 200. The conversion characteristic curve shown in FIG. 10 is rewritten by updating the light modulation data in the LUTs 102R, 102G, and 102B by the LUT update unit 1016.

  FIG. 11 is a flowchart illustrating an example of an operation related to updating of each LUT. First, based on the instruction information from the input / output unit 140, the test chart output control unit 1011 outputs a test chart 200 (test image) (step S1). The output test chart 200 is read by the colorimeter 22, and the density of each of the R, G, and B colors for each of the first to twentieth areas of the test chart 200 is detected (step S2). Based on the main correction amount calculated by the main correction amount calculation unit 1012 based on the density information for each of the R, G, and B colors detected by the colorimeter 22, the bias value for the AOMs 106R, 106G, and 106B is determined as a bias value calculation unit. 1013 (step S3).

  The gradation value of the light modulation data corresponding to the target density value in each area of the test chart 200 when the light amount correction of each light of R, G, B is performed based on the change of the bias value, and other than this target density value The gradation value of the light modulation data corresponding to the density value is set by the light modulation data setting unit 1014 (step S4). Then, the change rate of the gradation value of the light modulation data before and after correction is discriminated by the change rate discriminating unit 1015 (step S5), and when this change rate is equal to or greater than a predetermined value (YES in step S6), the test exposure is performed again. Therefore, it is generated in each AOM based on the gradation value of the light modulation data set in step S4 and the bias value calculated in step S3 (light modulation data is shifted by the bias value). A new test chart 200 is printed using the light modulation signal. If the change rate is smaller than the predetermined value (NO in step S6), the LUT update unit 1016 rewrites the contents of the LUTs 102R, 102G, and 102B using the light modulation data corresponding to each density value set in step S4. (Step S7).

  FIG. 12 is a flowchart showing an example of the operation relating to the calculation of the bias value in step S3 shown in FIG. First, an output characteristic curve (for example, the output characteristic curve 72 shown in FIG. 5) based on reading of the test chart 200 is created by the sensitometry creating unit 1017, and an output characteristic curve (for example, output) stored in the sensitometry storage unit 1021 is created. A characteristic curve 73) is read (step S11). From the information on the change in the image density (coloring level) of the photosensitive material 1 obtained based on these output characteristic curves created by the sensitometry creating unit 1017, the main correction amount calculating unit 1012 uses the R, G, and B lights. Is calculated (step S12). Based on the main correction amount calculated by the main correction amount calculation unit 1012, the inappropriate color generation light amount calculation unit 1018 calculates an inappropriate color generation light amount for each of the R, G, and B lights (step S13).

  The convergence determination unit 1020 determines whether or not the error value of the light amount obtained by adding the corrected main correction amount and the corrected inappropriate color light amount with respect to the main correction amount calculated in step S12 is equal to or smaller than a predetermined value. If it is determined that there is (YES in step S14), the repetitive calculation related to the calculation of the corrected improperly colored light amount calculation unit 1018 and the corrected main correction amount calculating unit 1019, respectively, regarding the calculation of the corrected improperly colored light amount and the corrected main correction amount is terminated. Based on the determined main correction amount obtained as a result of the end of the iterative calculation, a bias value for each AOM is calculated (step S15).

  When the convergence determining unit 1020 determines whether the error value of the light amount obtained by adding the corrected main correction amount and the corrected inappropriate color light amount with respect to the main correction amount is equal to or less than a predetermined value. (NO in step S14), the correction main correction amount based on the inappropriate color intensity is calculated by the correction main correction amount calculation unit 1019 (step S16). Then, the unsuitable coloring light amount calculation unit 1018 calculates a correction inappropriate color light amount based on the correction main correction amount calculated in step S16 (step S17). The calculations in steps S16 and S17 are repeatedly performed until the error in step S14 becomes a predetermined value or less.

  As described above, according to the laser exposure apparatus of the present invention, the conversion information in which the pixel data (density gradation data) and the level of the light modulation signal are associated with each other is stored in the first memory 102, and the MD 107R, 107G, 107B. Thus, an optical modulation signal is generated from the pixel data using the conversion information stored in the first memory 102, and the generated optical modulation signal is output to the AOMs 106R, 106G, and 106B. Also, a test chart drawn at a plurality of color levels (a plurality of densities and gray gradation images) using light modulation signals output from the MDs 107R, 107G, and 107B based on output control by the test chart output control unit 1011. 200 is formed on the photosensitive material.

  Then, the colorimeter 22 measures the color development level (density of each region) of the test chart 200 formed on the photosensitive material, and the color development level for light of each color including at least the change in sensitivity characteristic of the photosensitive material. Changes are acquired. That is, the colorimeter 22 detects the image density for each color of R, G, and B in each region of the test chart 200 printed by the test exposure. An output characteristic curve 72 is obtained based on the detected density information for each of the R, G, and B colors, and the main correction amount is determined based on a comparison between the output characteristic curve 72 and the reference output characteristic curve 73. Information on the change in the coloring level with respect to the light of each of the above colors can be obtained.

  On the other hand, a bias characteristic indicating the relationship between the level change of the light modulation signal with respect to the light of one color among the light of each color and the change in the inappropriate color generation level accompanying the level change of the light modulation signal Information is stored for each color of light by the bias characteristic information storage unit 1031. Then, the main control unit 101 stores the change in the color level acquired by the colorimeter 22 (and the sensitometry creation unit 1017) and stores it in the bias characteristic information storage unit 1031 so as to correct the color level to a predetermined color level. The level of the light modulation signal for each color is calculated using the bias characteristic information, and the conversion information stored in the first memory 102 is updated corresponding to the calculated light modulation signal.

  As described above, the bias characteristic information stored for each color of light by the bias characteristic information storage unit 1031 is used to compensate for the change in the color development level of the photosensitive material 1 and correct the color development level to a predetermined color development level. Since the level of the light modulation signal is automatically calculated, correction for variations in image density of the photosensitive material can be easily and accurately performed.

  The first memory 102 also stores LUTs 102R, 102G, and 102B that store conversion data in which pixel data (density gradation data) and light modulation data are associated with each other, and the light modulation data as a reference gradation of the light modulation data. And a bias information storage unit 1021 for setting a bias value for shifting the color development level of the photosensitive material 1 with respect to the value by a predetermined level (reference density), and the LUTs 102R, 102G by the MDs 107R, 107G, 107B. , 102B are shifted by the bias value output from the bias information storage unit 1021 to generate an optical modulation signal.

  The main control unit 101 obtains a bias value based on the correction of the color development level to compensate for the change in the color development level of the photosensitive material 1, and generates a light modulation signal generated based on the obtained bias value. Photosensitive material for light of each color when the photosensitive material 1 is colored by irradiating light of each color of R, G, B using (light modulation signal generated based on superimposition of light modulation data and bias value) The output characteristic (output characteristic curve 77) relating to one color development level is a reference output characteristic (output characteristic curve 73) that includes a color density level of a predetermined level, that is, a reference density value for a reference gradation value in the light modulation data. ), The gradation value of the light modulation data is corrected, and the stored contents of the LUTs 102R, 102G, and 102B are updated with the light modulation data obtained as a result of this correction.

  As described above, the light modulation is performed so that the output characteristic related to the color development level of the photosensitive material corresponding to the light modulation signal generated based on the bias value obtained by correcting the color development level of the photosensitive material 1 matches the reference output characteristic. Since the data is corrected, that is, the output characteristic curve 72 (output characteristic curve 77) and the output characteristic curve 73 not only match at the reference point 74 as described above, but also match at other points. Therefore, it is possible to correct the variation in the image density of the photosensitive material 1 with higher accuracy.

  Further, when the value of the light modulation data corresponding to the target density value of each region of each test chart 200 is corrected, the rate at which the value of the light modulation data before and after the correction changes, that is, the change rate is the change rate. If it is determined by the determination unit 1015 and the rate of change is large, a new test chart is printed (test exposure) using the light modulation data for each area after correction. Based on the reading of the test chart, the change rate of the light modulation data for each region is calculated, and the change rate is determined again. In this way, by checking the rate of change of the light modulation data before and after correction, it is possible to confirm whether the light modulation data is adjusted accurately by the correction, and thus the correction accuracy is further improved. be able to.

In addition, this invention can take the following aspects.
(A) In the above embodiment, the intensity of each RGB laser beam output from the laser light source is modulated via an optical modulation element such as an AOM. However, the present invention is not limited to this configuration, and is output from the laser light source. You may comprise so that the intensity | strength of a laser beam may be directly modulated. In this case, for example, in a laser driving unit such as the laser driving units (LD) 105R to 105B, light modulation (laser beam intensity modulation) is performed by directly modulating the driving power of the laser beam of each RGB color. Also good.

  Note that the laser driving means in this case is also an optical modulation means for performing the optical modulation, and the optical modulation means corresponds to the optical modulation element in the above embodiment.

  (B) In the above-described embodiment, the calculation is repeatedly performed until the difference (error) between the main correction amount and the light amount obtained by adding the corrected main correction amount and the correction inappropriate coloring light amount becomes a predetermined value or less. The number of repetition calculations (N times) may be set, and the repetition calculation may be performed for the set number of repetitions. The number of repetitions N is preferably a number of repetitions sufficient to reduce the error sufficiently.

  (C) In the embodiment described above, an output characteristic curve (for example, the output characteristic curve 73 shown in FIG. 7) serving as a reference for calculating the main correction amount (for example, the output characteristic curve 73 shown in FIG. 7) is used every time test exposure is performed. However, the reference output characteristic curve is not obtained by the update and is stored in advance in the output characteristic information storage unit 1020 or the like. It may be stored as a fixed value. Further, the reference density and the reference gradation value of the output characteristic curve as a reference may not be the density “0.9” and the 760 gradation, respectively.

  (D) The laser exposure apparatus of the present invention is not limited to the photographic developing apparatus 10 but may be applied to a vacuum fluorescent display (VFP), a liquid crystal shutter array, or the like.

1 is an overall configuration diagram of a photographic processing apparatus according to an embodiment of a laser exposure apparatus of the present invention. It is a figure which shows an example of a structure of the laser exposure unit in the photographic processing apparatus shown in FIG. It is a block diagram which shows an example of the signal path | route regarding the optical modulation by each AOM. It is a block diagram which shows the structure of the main control part shown in FIG.2 and FIG.3. It is a figure which shows an example of sensitometry. It is a figure which shows an example of sensitometry. It is a figure which shows an example of the bias characteristic which shows the change of the unsuitable coloring light quantity with respect to the light of G and B when the light quantity of R light is changed, (a) is a log value and (b) is a bias value. FIG. 5 is a diagram in which a bias value is a linear value. It is a figure which shows an example of the bias characteristic which shows the change of the unsuitable coloring light quantity with respect to the light of B and R at the time of changing the light quantity of G light, (a) is a log value and (b) is a bias value. FIG. 5 is a diagram in which a bias value is a linear value. It is a figure which shows an example of the bias characteristic which shows the change of the improper coloring light quantity with respect to the light of R and G at the time of changing the light quantity of B light, (a) is a log value and (b) is a bias value. FIG. 5 is a diagram in which a bias value is a linear value. It is a figure which shows an example of the conversion characteristic curve regarding the gradation conversion from pixel data (input gradation) to light modulation data (output gradation). It is a flowchart which shows an example of the operation | movement regarding the update of each LUT. 12 is a flowchart showing an example of an operation related to calculation of a bias value in step S3 shown in FIG. It is a figure which shows an example of a test chart. It is a figure which shows an example of the sensitivity characteristic with respect to each R, G, and B light in the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive material 1A Photosensitive material piece 10 Photographic processing apparatus (laser exposure apparatus)
12 Control unit 22 Colorimeter (measuring means)
71, 78 Sensitometry 72 Output characteristic curve 73 Output characteristic curve (reference characteristic)
76 Concentration difference 77 Output characteristic curve (characteristic)
100 Laser exposure unit (test image forming means)
101 Main control unit (calculation means)
1011 Test chart output control unit (test image forming means)
1012 Main correction amount calculation unit 1013 Bias value calculation unit 1014 Light modulation data setting unit (light modulation data correction means)
1015 Change rate determination unit 1016 LUT update unit (light modulation data correction means)
1017 Sensitometry creation unit (measuring means)
1018 Inappropriate coloring light amount calculation unit 1019 Correction main correction amount calculation unit 1020 Convergence determination unit 102 First memory (conversion information storage unit)
102R, 102G, 102B Look-up table (conversion data storage means)
1021 Bias information storage unit (bias value storage means)
1022 Sensitometry storage unit 103 Second memory 1031 Bias characteristic information storage unit (change characteristic storage unit)
104R, 104G, 104B Laser light source (light source)
105R, 105G, 105B Laser drive unit 106R, 106G, 106B Light modulation element 107R, 107G, 107B Light modulation element drive unit (light modulation signal generation means)
140 I / O unit 150 Image processing unit 151 Image data memory

Claims (2)

A light source for each color that emits light having a specific wavelength component is guided to the photosensitive material through at least two or more light sources that emit light having a specific wavelength component to cause color development. In a laser exposure apparatus for reproducing tone data on a photosensitive material,
Conversion data storage means for storing conversion data in which density gradation data and light modulation data are associated with each other as reference characteristics for obtaining a target color development level;
Conversion data update means for updating the conversion data;
The conversion data storage means using the conversion data stored by generating an optical modulated signal from the density level data, and the optical modulation signal generating means for outputting a modulated optical signal thus generated to the optical modulator,
Test image forming means for forming, on the photosensitive material, a test image drawn at a plurality of coloring levels using the light modulation signal output from the light modulation signal generating means;
Measuring means for measuring a color development level of a test image formed on the photosensitive material, and obtaining a change in color development level of each color including at least a change in color development sensitivity characteristics of the photosensitive material;
Sensitometry creating means for obtaining, for each color, sensitometry indicating the relationship between the light modulation data and the color development level based on the color development level of the test image measured by the measurement means;
A specific wavelength for the one color in the level change of the light modulation signal for one of the colors, and the color development level of the photosensitive material by the other color accompanying the level change of the light modulation signal Change characteristic storage means for storing, for each color, a change characteristic indicating a relationship with a change in an improper coloring level that occurs due to mixing of components;
To correct the difference and shift the sensitometry to match the converted data when the color development level in the sensitometry corresponding to the light modulation data is different from the density gradation data of the converted data, respectively. A main correction amount calculating means for calculating a main correction amount of necessary light modulation data;
A bias value calculation means for calculating a bias value necessary for further shifting the sensitometry, which reflects an inappropriate color development level with respect to the main correction amount, and
The bias value calculation means includes
Using the change characteristic stored in the change characteristic storage unit, an unsuitable color level calculating unit for calculating the unsuitable color level for the main correction amount calculated by the main correction amount calculating unit;
Correction main correction amount calculation means for obtaining a correction main correction amount for further correcting the main correction amount using the inappropriate color generation level calculated by the inappropriate color generation level calculation means,
The conversion data updating unit updates conversion data based on the correction main correction amount . 2. The laser exposure according to claim 1, wherein the setting of the bias value, the calculation of the inappropriate color generation level, and the calculation of the correction main correction amount are repeated until an error with respect to a predetermined color generation level becomes a predetermined value or less. apparatus.