JP2006297792A - Image exposure system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image exposure system which can eliminate the influence of tailing in a sub-scanning direction and suppress the variation of data when an image is formed by using a liquid crystal shutter. <P>SOLUTION: This image exposure system comprises: a light source; the liquid crystal shutter 21 which is arranged on the optical-axis-direction front side of the light source, which can control the transmission/shielding of exposure light, and which is composed of a pixel group arranged along a main-scanning direction and a pixel group arranged along a sub-scanning direction; a cylindrical lens 22 which is arranged ahead of the liquid crystal shutter 21 so as to make the exposure light form the image on a photographic sensitive material; a pixel data splitting means 4c for splitting pixel data, equivalent to one pixel, depending on the number of the pixels of the pixel group arranged in the sub-scanning direction, and turning the split pixel data into a histogram; and a shutter control means 6a for controlling each of the pixels constituting the liquid crystal shutter 21, depending on the value of the split pixel data. In the performance of the exposure equivalent to one pixel, after the light applied from the light source is transmitted through the pixel group which is arranged along the sub-scanning direction, the lens 22 makes the light converge into the exposure light with a size equivalent to one pixel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image exposure apparatus that forms an image on the surface of an image forming medium by irradiating exposure light in the main scanning direction of the surface of the image forming medium while moving the image forming medium along the sub-scanning direction. Is.

  An image exposure apparatus disclosed in the following Patent Document 1 is an image exposure apparatus that forms an image on the surface of a photographic photosensitive material by irradiating a photographic photosensitive material (corresponding to an image forming medium) with exposure light based on image data. Has been proposed. In this image exposure apparatus, LEDs of R, G, and B colors, cylindrical lenses, liquid crystal shutters, and SLA (self-focusing fiber array) are arranged along the optical axis. Each light emitted from the LED passes through the cylindrical lens and becomes slit light beams in a direction corresponding to one line direction (main scanning direction) of the photosensitive material, which passes through the liquid crystal shutter and forms an image on the photosensitive material.

  On the other hand, when a liquid crystal shutter is used, a phenomenon called tailing may adversely affect the image quality of the liquid crystal. This will be described with reference to FIG. FIG. 3A conceptually shows a state in which pixels in the photographic photosensitive material are exposed. When the pixel density is considerably higher than the surrounding area, exposure may be performed in a state where the tail is pulled as shown in (b), which is referred to as tailing. Such a tailing phenomenon causes a deterioration in image quality, and thus needs to be improved. Further, the tailing phenomenon is a phenomenon that can occur in both the main scanning direction and the sub-scanning direction, and it is possible to erase the tailing only in the main scanning direction by electronic signal processing or the like. It is difficult to erase the tails that occur in the sub-scanning direction.

  Also, when image exposure is performed on a photographic photosensitive material line by line using a liquid crystal shutter, gradation expression is performed by changing the amount of light transmitted through each pixel constituting the liquid crystal shutter by some method. When changing data line by line, if the amount of data change is large, the reaction speed of the liquid crystal may not be able to follow, and as a result, the image quality may be degraded.

Japanese Patent Laid-Open No. 7-301868 (abstract, claims, etc.)

  The present invention has been made in view of the above circumstances, and its problem is that when image formation is performed using a liquid crystal shutter, the influence of tailing in the sub-scanning direction can be eliminated, and the amount of data change can be suppressed. An image exposure apparatus is provided.

In order to solve the above problems, an image exposure apparatus according to the present invention provides:
An image exposure apparatus that forms an image on the surface of an image forming medium by irradiating exposure light in the main scanning direction of the surface of the image forming medium while moving the image forming medium along the sub-scanning direction,
A light source for exposure;
A pixel group disposed along the main scanning direction and a pixel group disposed along the sub-scanning direction, which is disposed on the front side in the optical axis direction of the exposure light source and can control the transmission and blocking of the exposure light. A liquid crystal shutter constituted by a group;
An imaging lens that is arranged on the front side of the liquid crystal shutter in the optical axis direction and forms an image of the exposure light on the surface of the image forming medium;
Pixel data dividing means for dividing the pixel data for one pixel into a histogram by dividing the pixel data according to the number of pixels of the pixel group arranged in the sub-scanning direction;
Shutter control means for controlling each pixel constituting the liquid crystal shutter according to the value of the divided pixel data,
When performing exposure for one pixel, the light emitted from the light source for exposure is transmitted through the pixel group arranged along the sub-scanning direction, and then focused on the exposure light of one pixel size by the imaging lens. It is characterized by having made it comprise.

  The operation and effect of the image exposure apparatus will be described. In this image exposure apparatus, an exposure light source, a liquid crystal shutter, and an imaging lens are arranged along the optical axis direction. In addition, the image exposure apparatus sequentially forms an image line by line along the main scanning direction. However, the liquid crystal shutter does not have a configuration in which pixels are arranged in a line, but pixels along the main scanning direction. And a group of pixels along the sub-scanning direction. That is, the shape of the light transmission part of the liquid crystal shutter is not a line but a plane. Further, when performing exposure for one pixel, image exposure is performed using a pixel group arranged in the sub-scanning direction. That is, in order to form a pixel for one pixel on the image forming medium, the exposure light is transmitted using the pixel group in the sub-scanning direction, and then focused on the image forming medium by the imaging lens. Since the exposure light for one pixel is thus divided into a plurality of pixel groups, the density difference between adjacent pixels can be reduced on the liquid crystal shutter, and the influence of tailing can be eliminated.

  On the liquid crystal shutter, the exposure light is transmitted through the pixel group in the sub-scanning direction on the liquid crystal shutter. Therefore, the pixel data for one pixel is divided into a histogram according to the number of pixels. . Each pixel of the liquid crystal shutter can be controlled based on the divided pixel data. Thereby, the density difference between adjacent pixels can be reduced, the influence of tailing can be eliminated, and the amount of change in data can also be suppressed by dividing pixel data. As a result, when image formation is performed using a liquid crystal shutter, it is possible to provide an image exposure apparatus that can eliminate the influence of tailing in the sub-scanning direction and further suppress the amount of data change.

  In the present invention, it is preferable that the histogram formation is performed by the image data dividing unit so that the density difference between pixels in the sub-scanning direction is small.

  By reducing the density difference between the pixels, the influence of tailing can be effectively eliminated. In addition, a histogram can be formed so that the amount of data change can also be suppressed.

  In the present invention, the number of pixels of the pixel group in the sub-scanning direction is set according to the gradation, and gradation is expressed by performing ON / OFF control of each pixel by the shutter control means. It is preferable.

  When the gradation of pixels is expressed using a liquid crystal shutter, the number of pixels in the sub-scanning direction can be set according to the gradation. For example, when 8-bit gradation expression is performed, a liquid crystal shutter may be configured by arranging 256 pixels in the sub-scanning direction. Thereby, gradation expression can be performed by performing ON / OFF control of each pixel.

  In the present invention, it is preferable to perform gradation expression by controlling the amount of light transmitted through each pixel constituting the liquid crystal shutter and the number of pixels of the pixel group arranged in the sub-scanning direction.

  In the case of gradation expression, it is also possible to control the amount of transmitted light of each pixel constituting the liquid crystal shutter. Therefore, by combining with the setting of the number of pixels arranged in the sub-scanning direction, more multi-level gradation expression can be realized. For example, if the number of pixels in the sub-scanning direction is 256 (8 bits) and the amount of transmitted light of each pixel is controlled by 4 bits, 12-bit gradation expression is possible. Thereby, multi-level gradation expression can be performed without increasing the number of pixels of the pixel group in the sub-scanning direction.

In the present invention, a photosensitive material information reading unit for acquiring type data of an image forming medium,
It is preferable to include an exposure pixel setting unit that sets the number of pixels to be used for image exposure among the pixel groups arranged along the sub-scanning direction based on the acquired type data.

  Image forming media have different color development characteristics depending on the type. That is, even when the same amount of light is given, the degree of color development is different, and it is necessary to give a larger amount of light to an image forming medium with low sensitivity than an image forming medium with high sensitivity. Therefore, the type data of the image forming medium is acquired, and based on this, the number of pixels in the sub-scanning direction used for image exposure is set. For example, a larger number of pixels is set for an image forming medium with low sensitivity. By providing such a bias function, it is possible to absorb a color development characteristic difference between image forming media.

  A preferred embodiment of an image exposure apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a photographic processing system in which an image exposure apparatus is used. This photographic processing system has a function of acquiring digital image data from a photographic film or a storage medium and creating a photographic print.

<Photo processing system configuration>
The film scanner 1 has a function of scanning a frame image formed on a developed photographic film (negative film or positive film) and acquiring image data of the frame image. The medium loading unit 2 can load a storage medium and can read image data stored in the storage medium. Examples of the storage medium include a recording medium such as a compact flash (registered trademark) smart media (registered trademark) for a digital camera, and a recording medium such as an MO disk and a CD-R. The film scanner 1 and the medium mounting unit 2 function as an image input unit. The input image data is stored in the image data storage unit 3. The image data storage unit 3 can be composed of a storage device such as a hard disk, and stores and manages the acquired image data in order units (one film, one recording medium, etc.).

  Although a photographic print is created using the acquired image data, the print processing is performed after the image processing is performed in the image processing unit 4 instead of immediately performing the print processing. The correction parameter setting unit 4a provides a function for setting a correction parameter. For example, the image data is displayed on the monitor 5 and the operator determines whether or not a photo print is created with appropriate colors and densities. If necessary, color / density correction values are input and set as correction parameters. In addition, these correction parameters are set when special correction such as red-eye correction or backlight correction is performed, or when trimming is performed. The image correction unit 4b has a function of creating corrected image data using the set correction parameters and the original image data input by the image input unit. The correction result by the correction parameter can be confirmed on the monitor 5.

The image data dividing unit 4c has a function of further dividing pixel data for one pixel. An image formed on a photographic print can be thought of as a collection of many pixels. The data representing the entire image is called image data, and the data of the pixels that make up the image is the pixel data. I will call it. In the case of color image data, individual pixel data can usually be expressed in the form of (R, G, B), but in the case of the present invention, the pixel data is further (R ₁ , G ₁ , B ₁ ) (R ₂ , G ₂ , B ₂ )... (R _n , G _n , B _n ) and divided into n to form a histogram. This will be described later.

  The print image data generation means 4d creates a photographic print based on the original image data, the correction parameters described above, the division function by the image data division means 4c, and other correction functions (correction by CMS processing, shading correction, etc.) A function for generating print image data for the purpose is provided.

  The image transfer unit 5 has a function of transferring the generated print image data to the exposure control unit 6. The image transfer unit 5 is provided with a transfer memory 5a that functions as a buffer.

  The exposure engine 7 (functioning as an image exposure device) has a function of printing and exposing an image on the emulsion surface of the photographic material using the liquid crystal shutter 21. The exposure engine 7 includes a halogen lamp 20 as an exposure light source, and a liquid crystal shutter 21 that controls transmission and blocking (ON / OFF and transmitted light amount) of irradiation light (corresponding to exposure light) emitted from the halogen lamp 20. A cylindrical lens 22 (corresponding to an imaging lens) is provided for converging the light that has passed through the liquid crystal shutter 21 onto the photographic photosensitive material.

  The exposure control unit 6 has a function of controlling the exposure engine 7, and the shutter control unit 6 a controls the driving of the liquid crystal shutter 21 based on the print image data transferred from the image transfer unit 5. Liquid crystal driving circuit. The light source drive control means 6 b performs drive control for turning on / off the halogen lamp 20. Other functions of the exposure control unit 6 will be described later.

  Next, a configuration relating to a processing system of a photographic photosensitive material (also referred to as paper, which corresponds to an image forming medium) will be briefly described. Photosensitive material is accommodated in the paper magazine 10 in a state of being wound around a roll. The long photographic photosensitive material drawn out from the paper magazine 10 is cut into a predetermined print size by the paper cutter 11. The photographic photosensitive material cut into the print size is conveyed to the exposure engine 7, and the exposure engine 7 performs image printing exposure while being conveyed along the conveyance path by the exposure conveyance roller 12. Driving control for the exposure transport roller 12 is also performed by the exposure controller 6.

  The photographic light-sensitive material on which the image is printed and exposed is transported by a transport mechanism, subjected to development processing and drying processing in the development processing section 13 and the drying processing section 14, and then finished as a finished photographic print from the print discharge section 15. It is discharged outside the device.

<Configuration of exposure engine>
Next, the configuration of the exposure engine 7 will be described in detail with reference to FIG. A halogen lamp 20, a filter 23, a liquid crystal shutter 21, and a cylindrical lens 22 are arranged in this order from the upper end side along the exposure optical axis. In addition, the optical element arrange | positioned along an optical axis is not necessarily limited to these, For example, you may arrange | position an additional optical element (for example, diffuser plate). Moreover, the optical axis does not need to be a straight line, and the optical path may be bent according to circumstances such as space. In this case, optical elements such as a mirror and a prism are further arranged.

  The rotary filter 23 includes color filters 23R, 23G, and 23B of R, G, and B colors, and any one filter is inserted into the optical path. Thereby, the irradiation light from the halogen lamp 20 can be converted into exposure light of each color, and a color image can be formed. The rotary filter 23 is rotationally driven by a rotational drive mechanism (not shown). In the rotary filter 23, the filter drive control means 6c controls the drive of the rotary filter 23.

  As shown in FIG. 2, the photographic photosensitive material P is conveyed along the conveyance path by the exposure conveyance roller 12, that is, along the sub-scanning direction. The driving of the exposure transport roller 12 is controlled by the exposure transport roller control means 6d. When an image is printed on the emulsion surface of the photographic material P, exposure light is irradiated line by line (indicated by L) along the main scanning direction while the photographic material P is conveyed along the sub-scanning direction. Then, images are sequentially formed.

The liquid crystal shutter 21, the pixels G ₁₁ along the main scanning direction, G ₂₁ · · · G _n1 is disposed pixels G _11, G ₁₂ · · · G ₁₈ are arranged along the sub-scanning direction. A group of pixels along the main scanning direction is referred to as a first pixel group, and a group of pixels along the sub-scanning direction is referred to as a second pixel group. In the example of FIG. 2, the first pixel group is composed of n pixels, and the second pixel group is composed of eight pixel groups. That is, the entire liquid crystal shutter 21 is configured by 8 × n number of pixels. The number n of pixels in the first pixel group corresponds to the number of pixels in the main scanning direction formed in the photographic photosensitive material P, but the number of pixels 8 in the second pixel group is equal to the number of pixels in the second pixel group. The above corresponds to one pixel. That is, the exposure light is in the state of a surface at the time of the liquid crystal shutter 21, but is converged in a line shape in the photographic photosensitive material P. The cylindrical lens 22 has a function of focusing exposure light.

As described above, in order to represent one pixel by the second pixel group along the sub-scanning direction, it is necessary to divide the pixel data by the image data dividing unit 4c and form a histogram. Various methods of dividing can be considered, and specific examples are shown in FIG. FIG. 4A shows an example in which the data value is 38 and is divided into 8, 8, 6, 6, 4, 4, 2, 0. In this case, the density difference between adjacent pixels in the sub-scanning direction is 0 or 2, which is small. Therefore, the influence of tailing can be suppressed. On the other hand, when dividing into 10, 10, 10, 8, 0, 0, 0, 0 as shown in FIG. The degree of inhibition is smaller than (a). Further, when the density value is gradually changed as shown in FIG. 4A, even if the data amount of the next main scanning line (total data amount for 8 pixels in the sub-scanning direction) greatly changes, For the pixels G ₁₁ , G ₂₁ ... G _n1 , the amount of change is small, so that the reaction speed of the liquid crystal is sufficiently high.

Other histograms can be divided equally. For example, if the density value of a pixel is 80, this can be simply averaged to give G ₁₁ = 10 and G ₁₂ · 10 ·· G ₁₈ = 10. However, it is considered that the dividing method shown in FIG. 4A is more effective in reducing the amount of data change. Accordingly, when forming a histogram, pixel data is divided so that the density difference between adjacent pixels is as small as possible (so that the data amount gradually changes). In addition, various data division methods are conceivable.

  According to the exposure method as described above, as schematically shown in FIG. 2, even if tailing H1 in the sub-scanning direction occurs in the liquid crystal shutter 21, as indicated by H2 on the photographic photosensitive material P. Since the light is focused, it is possible to prevent deterioration in image quality due to the influence of tailing. In the present embodiment, 8 pixels in the sub-scanning direction are focused so as to become one actual pixel, but the number of divided pixels in the sub-scanning direction is not limited to this. The tailing that occurs in the main scanning direction can be eliminated by electronic signal processing.

  The image data includes data for each of R, G, and B, and the exposure light of each color is generated while the rotary filter 23 is switched, and the image of each color is printed and exposed on the photosensitive material P. Further, each pixel data constituting the image data is divided into eight corresponding to the number (8) of the second pixel group, and then transferred to the exposure control unit 6. Based on the divided pixel data, drive control for the liquid crystal shutter 21 is performed. Each pixel of the liquid crystal shutter 21 can be turned ON / OFF, and gradation expression can be performed by controlling the length of the ON time. Alternatively, gradation expression may be performed by controlling the light transmittance according to the voltage applied to each pixel.

  The order of image formation can be performed as follows, for example. First, the R (red) filter 23R of the rotary filter 23 is exposed to the optical path, the liquid crystal shutter 21 is controlled by the R image data, and an image for one line is formed on the photosensitive material P by the R exposure light. Next, the G (green) filter 23G is exposed to the optical path, an image for one line is formed by the G exposure light, and then the B (blue) filter 23B is exposed to the optical path, and the B exposure light is used. An image for one line is formed. As a result, R, G, and B images (latent images) for one line are printed and exposed. Subsequently, image formation can be performed by repeating image exposure for the next one line of R, G, and B in the same manner. The conveyance speed of the photographic photosensitive material P in the sub-scanning direction and the rotation speed of the rotary filter 23 can be determined in accordance with the scanning speed in the main scanning direction.

  The liquid crystal shutter 11 is preferably provided with a temperature adjusting mechanism so that the environmental temperature becomes a predetermined temperature. In general, the reaction rate of liquid crystals is slow at low temperatures and fast at high temperatures. Due to such temperature characteristics, when the environmental temperature changes, the intensity of exposure light applied to the photographic photosensitive material changes. Therefore, it is possible to prevent the liquid crystal ON / OFF switching ability from being lowered by adjusting the temperature so as to be a predetermined temperature.

<Embodiment of gradation expression>
In order to obtain the gradation expression of the pixels formed on the photographic material, it is necessary to change the amount of light for exposing the photographic material. By setting the amount of light in stages, gradation expression can be performed, and the gradation can be increased as the number of stages is increased. FIG. 5 shows an embodiment for performing gradation expression, and gradation setting can be performed according to the number of pixels in a pixel group arranged along the sub-scanning direction. For example, 8-bit gradation can be expressed by arranging 256 pixels in the sub-scanning direction. By arranging 4096 pixels, 12-bit gradation can be expressed. According to such a configuration, since ON / OFF control is sufficient for each pixel, control by the shutter control unit 6a can be simplified.

  As another method, gradation expression can be performed by controlling the number of pixels in the sub-scanning direction and the amount of transmitted light for each pixel. For example, if the number of pixels in the sub-scanning direction is set to 256 (corresponding to 8 bits) and each pixel of the liquid crystal shutter 21 is controlled with 4 bits, a total 12-bit gradation expression can be performed. The amount of light transmitted through each pixel of the liquid crystal shutter 21 can be controlled by changing the voltage applied to the pixel. Therefore, desired gradation expression can be performed by a combination of rough gradation control of each pixel of the liquid crystal shutter 21 and setting of the number of pixels in the sub-scanning direction. It is possible to appropriately determine how to share the control of each pixel and the setting of the number of pixels with respect to the total gradation.

<Bias function of LCD shutter>
Next, a configuration in which the liquid crystal shutter 21 has a bias function will be described with reference to FIG. Photosensitive materials have different color development characteristics depending on the type. That is, even when the same amount of light is given, the degree of color development is different, and it is necessary to give a larger amount of light to a photographic photosensitive material with low sensitivity than to a photographic photosensitive material with high sensitivity. Therefore, the type data of the photographic photosensitive material is acquired, and based on this, the number of pixels in the sub-scanning direction used for image exposure is set.

Therefore, as shown in FIG. 6, the photosensitive material information reading unit 30 can read photographic photosensitive material information (photographic photosensitive material size, color development characteristics, ID, etc.) from the paper magazine 10. The exposure pixel setting means 6a of the exposure control unit 6 sets the number of pixels in the sub-scanning direction used for exposure based on the type data of the photographic photosensitive material read by the photosensitive material information reading unit 30. For example, depending on the type, pixels in a range indicated by N ₁ , N ₂ , and N ₃ are used for exposure. If sensitivity is high photographic material, pixels in the range of N ₁ is a smaller number of pixels is used for exposure, and the other pixels are not being used for exposure. By setting the number of pixels to be used in this way, a bias function can be provided, and the difference in color development characteristics of the photographic photosensitive material can be absorbed.

  Conventionally, a dimming filter is used to absorb the difference in color development characteristics. However, according to the present invention, such a dimming filter is not necessary, and thus the configuration can be simplified.

<Another Embodiment of Light Source for Exposure>
Next, another embodiment of the exposure light source will be described. FIG. 7 shows a configuration example in which LEDs 25R, 25G, and 25B of R (first color), G (second color), and B (third color) are arranged instead of a halogen lamp as an exposure light source. In the case of the halogen lamp 20, there are problems such as maintenance for replacement and change with time because the lifetime is short. Further, as shown in FIG. 2, the rotary filter 23 is required. However, when the LED 25 is used as shown in FIG. 7, the rotary filter 23 is not necessary and has a long life. The problem can be eliminated.

  When the LED 25 is used, the LED 25 and the liquid crystal shutter 21 can be arranged apart from each other as shown in FIG. In this case, an optical system for guiding exposure light from each LED 25 to the back surface of the liquid crystal shutter 21 is required. Each LED 25 is composed of a large number of LED chips, and a large number of LED chips are arranged along the main scanning direction.

  The configuration example of FIG. 7B is an example in which a large number of LED chips 25 are arranged on the back side of the liquid crystal shutter 21. In this case, the R, G, and B color chips can be arranged corresponding to the pixels constituting the liquid crystal shutter 21. Accordingly, the liquid crystal shutter 21 is divided in advance into an area for forming an R image, an area for forming a G image, and an area for forming a B image.

  In the case of forming an image with the configuration example of FIG. 7A, it can be the same as described in FIG. That is, first, the R-LED 25R is turned on, the R image is printed and exposed based on the R image data, and then the G image and the B image are sequentially printed and exposed for one line. . Hereinafter, by repeating this, an image can be formed on the photographic material P. In the case of FIG. 7B, since the areas of the respective colors are set in advance, images for three colors can be simultaneously formed on the photographic photosensitive material P. Therefore, the image forming time can be shortened.

<Another embodiment>
Various light sources can be used as the light source for exposure, and for example, a white LED may be used. When a white LED is used, color data of each color can be expressed by arranging a color filter in accordance with the pixel size on the front surface of the liquid crystal shutter 21. Further, when a halogen lamp is used, a color filter may be arranged in front of the liquid crystal shutter 21 instead of using the rotary filter 23 as shown in FIG.

  In the present embodiment, a photographic photosensitive material has been described as an example of the image forming medium. However, the present invention is not limited to this, and other types of photosensitive material, for example, a rotationally driven photosensitive drum may be used. . A lens other than a cylindrical lens may be used as the imaging lens.

  The imaging lens 22 may be a combination of a plurality of lenses instead of a single lens.

  As a modification of the embodiment shown in FIG. 7, the pixel group in the sub-scanning direction of the liquid crystal shutter 21 is equally divided into three regions along the sub-scanning direction, and the uppermost 1/3 pixel group is set as R. -The region for the LED 25R, the central 1/3 pixel group may be the G-LED 25G region, and the bottom 1/3 pixel group may be the B-LED 25B region. In this case, each color image can be formed simultaneously.

Schematic diagram showing the configuration of the photo processing system Schematic diagram showing the configuration of the image exposure apparatus Diagram explaining the tailing phenomenon The figure explaining the histogram-ization of pixel data The figure which shows the structural example for performing gradation expression The figure which shows the configuration where the liquid crystal shutter has the bias function The figure which shows another embodiment of the light source for exposure

Explanation of symbols

4 image processing unit 4c image data dividing unit 4d printing image data generating unit 6 exposure control unit 6a shutter control unit 6b light source drive control unit 6c filter drive control unit 6d exposure transport roller control unit 6e exposure pixel setting unit 7 exposure engine (exposure engine) Image exposure device)
DESCRIPTION OF SYMBOLS 10 Paper magazine 20 Halogen lamp 21 Liquid crystal shutter 22 Cylindrical lens 23 Rotation filter 23R Filter 23G Filter 23B Filter 30 Sensitive material information reading part

Claims (5)

An image exposure apparatus that forms an image on the surface of an image forming medium by irradiating exposure light in the main scanning direction of the surface of the image forming medium while moving the image forming medium along the sub-scanning direction,
A light source for exposure;
A pixel group disposed along the main scanning direction and a pixel group disposed along the sub-scanning direction, which is disposed on the front side in the optical axis direction of the exposure light source and can control the transmission and blocking of the exposure light. A liquid crystal shutter constituted by a group;
An imaging lens that is arranged on the front side of the liquid crystal shutter in the optical axis direction and forms an image of the exposure light on the surface of the image forming medium;
Pixel data dividing means for dividing the pixel data for one pixel into a histogram by dividing the pixel data according to the number of pixels of the pixel group arranged in the sub-scanning direction;
Shutter control means for controlling each pixel constituting the liquid crystal shutter according to the value of the divided pixel data,
When performing exposure for one pixel, the light emitted from the light source for exposure is transmitted through the pixel group arranged along the sub-scanning direction, and then focused on the exposure light of one pixel size by the imaging lens. An image exposure apparatus characterized in that the apparatus is configured to perform the above.   The image exposure apparatus according to claim 1, wherein the histogram is formed by the image data dividing unit so that a density difference between pixels in the sub-scanning direction is reduced.   The number of pixels in the pixel group in the sub-scanning direction is set according to the gradation, and gradation expression is performed by performing ON / OFF control of each pixel by the shutter control unit. The image exposure apparatus according to claim 1 or 2.   The image according to claim 1 or 2, wherein gradation expression is performed by controlling the amount of light transmitted through each pixel constituting the liquid crystal shutter and the number of pixels of the pixel group arranged in the sub-scanning direction. Exposure device. A photosensitive material information reading unit for acquiring type data of the image forming medium;
2. An exposure pixel setting unit that sets the number of pixels to be used for image exposure among pixel groups arranged along the sub-scanning direction based on the acquired type data. The image exposure apparatus of any one of -4.

Images