JP2006301355A - Image exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image exposure apparatus capable of eliminating an influence of tailing in a sub scanning direction in the case of forming an image by using a liquid crystal shutter. <P>SOLUTION: Regarding the image exposure apparatus for forming the image on the surface of a photographic photosensitive material by irradiating the surface of an image forming medium with exposure light in a main scanning direction while moving the photographic photosensitive material along the sub scanning direction, the image exposure apparatus includes an exposure light source (halogen lamp or LED), the liquid crystal shutter 21 arranged ahead of the exposure light source in the optical axis direction, also, capable of controlling to transmit/shut off the exposure light, and constituted of a pixel group arranged along the main scanning direction and a pixel group arranged along the sub scanning direction, and a cylindrical lens 22 arranged ahead of the liquid crystal shutter 21 in the optical axis direction, for imaging the exposure light on the surface of the image forming medium, and in the case of exposing for one pixel, the light emitted from the exposure light source is transmitted through the pixel group arranged along the sub scanning direction, thereafter, the light is converged by the imaging lens so as to become the exposure light as large as 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.

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

  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.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image exposure apparatus that eliminates the influence of tailing in the sub-scanning direction when image formation is performed using a liquid crystal shutter. .

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;
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. As a result, it is possible to provide an image exposure apparatus that eliminates the influence of tailing in the sub-scanning direction when image formation is performed using a liquid crystal shutter.

In the present invention, pixel data dividing means for dividing pixel data for one pixel in accordance with the number of pixels in a pixel group arranged in the sub-scanning direction;
It is preferable to include a shutter control unit that controls transmission / cutoff of each pixel constituting the liquid crystal shutter according to the value of the divided pixel data.

  On the liquid crystal shutter, since the exposure light is transmitted using the pixel group in the sub-scanning direction on the liquid crystal shutter, the pixel data for one pixel is divided according to the number of pixels. Based on the divided pixel data, transmission / cutoff of each pixel of the liquid crystal shutter can be controlled. Thereby, the density difference between adjacent pixels can be reduced and the influence of tailing can be eliminated.

  In the present invention, the light source for exposure is preferably composed of LEDs of the first color, the second color, and the third color for forming a color image. By using the LED, the life of the light source can be extended as compared with the case of using a halogen lamp, and the working time required for maintenance can be greatly reduced.

  In the present invention, the exposure light source is preferably a white LED. Thereby, the lifetime of the light source can be extended, and the work time required for maintenance can be significantly reduced.

In the present invention, a plurality of types of filters arranged in front of the LEDs and prepared according to the photosensitive characteristics of the image forming medium,
It is preferable to include a filter switching mechanism that switches the filter according to the type of image forming medium.

  When an LED is used as the exposure light source, the wavelength range of the LED is narrow, so that it may not match the sensitivity characteristics of the image forming medium. Further, the sensitivity characteristics of the image forming medium vary depending on the type of the image forming medium. Therefore, the color development characteristics differ due to such a shift in the wavelength range, and an image of a desired color may not be formed. Therefore, a plurality of filters are prepared according to the type of image forming medium, and the filters are switched according to the image forming medium to be used. Thereby, image formation can be performed with exposure light according to the photosensitive characteristics of the image forming medium.

  In the present invention, first, second and third color filters for forming a color image are arranged on the front surface of the liquid crystal shutter, and the pixel group constituting the liquid crystal shutter is divided into regions corresponding to the respective colors. Preferably it is.

  As a method for generating exposure light of each color for forming a color image, a color filter corresponding to three colors may be arranged on the front surface of the liquid crystal shutter. In this case, the pixel group constituting the liquid crystal shutter is divided into regions corresponding to the respective colors. According to this configuration, when a halogen lamp is used as an exposure light source, for example, a driving mechanism for inserting filters of each color is not required, vibration due to filter driving can be eliminated, and the configuration can be simplified. Can do.

  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 is divided into n pieces. 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, a liquid crystal shutter 21 that controls transmission and blocking (ON / OFF) of irradiation light (corresponding to exposure light) emitted from the halogen lamp 20, and a liquid crystal shutter. A cylindrical lens 22 (corresponding to an imaging lens) for converging the light that has passed through 21 onto the photographic material is provided.

  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, since one pixel is represented by the second pixel group along the sub-scanning direction, the pixel data needs to be divided by the image data dividing unit 4c. Various division methods are conceivable. For example, the division can be performed 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. Of course, the present invention is not limited to this, and the pixel data can be divided according to other rules.

  According to such an exposure method, as schematically shown in FIG. 2, even if the liquid crystal shutter 21 has tailing H1 in the sub-scanning direction, it is focused on the photographic photosensitive material P as indicated by H2. Therefore, it is possible to prevent image quality deterioration 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.

<Another Embodiment of Light Source for Exposure>
Next, another embodiment will be described. FIG. 4 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. 4, 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. 4B 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.

  When image formation is performed with the configuration example of FIG. 4A, it can be performed in the same manner 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. 4B, since the areas for the respective colors are set in advance, images for three colors can be formed on the photographic photosensitive material P at the same time. Therefore, the image forming time can be shortened.

  FIG. 5 shows an example in which an LED is used as an exposure light source, but a configuration example in which a white LED unit 26 is used. In the white LED unit 26, a large number of LED chips 26a are two-dimensionally arranged. When the white LED unit 26 is used, R, G, and B color filters 27 are disposed on the front surface of the liquid crystal shutter 21 to generate color exposure light. As shown in the enlarged view of FIG. 5B, the color filter 27 is composed of a collection of fine R, G, and B filters, and the size of each filter corresponds to the size of the pixel. 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. Therefore, images for three colors can be formed on the photographic material P at the same time. By using such a white LED, the rotary filter 23 can be eliminated and the maintenance problem can be solved.

  FIG. 6 is an example in which a color filter 27 is disposed in front of the liquid crystal shutter 21 in a configuration example using the halogen lamp 20. Also in this case, the rotation filter 23 can be eliminated, the configuration can be simplified and the image forming time can be shortened.

<Matching sensitivity characteristics 1>
When an LED is used as the light source for exposure, it is difficult to match the sensitivity of the photographic photosensitive material because the LED has a narrow wavelength range, so even if a slight change occurs in the light source, the color of the photographic photosensitive material is greatly affected. May occur. Since such an effect is different for each type of photographic light-sensitive material, characteristics are examined in advance for each type of photographic light-sensitive material, and image data is corrected. For example, by preparing a test print on which a predetermined image is formed and measuring the degree of color development, a correction table is prepared for each type of photographic light-sensitive material, and image data can be corrected based on this. it can.

  In the case of an exposure light source using a halogen lamp, it is possible to cope with the wide wavelength range. However, in the case of using an LED, it is practically difficult to cope with only a correction table. Therefore, it is preferable to match the characteristics of the exposure light from the LED with the photosensitive characteristics of the photographic photosensitive material in advance. A configuration example for this will be described with reference to FIG.

  As shown in FIG. 7, a plurality of types of filters 28 a to 28 d are configured to be selectively detachable on the front surface of the LED 25. The filter switching mechanism 29 can position any one of the filters 28 a to 28 d on the front surface of the LED 25. The paper magazine 10 is formed so that the information of the photographic photosensitive material accommodated therein can be read by a sensor. The photosensitive material information reading unit 30 can read photographic photosensitive material information (such as the size, color development characteristics, and ID of the photographic photosensitive material) from the paper magazine 10. The filter drive control means 6c of the exposure control unit 6 controls the filter switching mechanism 29 so that any one of the filters 28a to 28d is inserted based on the read photosensitive material information. As a result, image formation can be performed by exposure light that matches the characteristics of the photographic material. Further, by adjusting the characteristics of the exposure light with the characteristics of the photographic photosensitive material, the correction amount by the correction table described above can be reduced. If the correction amount is small, the time until the correction table is acquired can be shortened.

  In FIG. 7, the same components as those described with reference to FIG. FIG. 8 is a diagram showing the action of the filter, and it can be seen that the peak of the characteristic curve R of the R-LED is moved to R ′ by the filter.

<Matching sensitivity characteristics 2>
Although the method of matching the sensitivity characteristics when LEDs are used as the exposure light source has been described, it can be solved by methods other than filter insertion. That is, the LED has a temperature characteristic, and when the temperature changes, the wavelength characteristic changes. Focusing on this point, it is possible to perform matching with the sensitivity characteristics of the photographic material. In order to change the environmental temperature of the LED, for example, a heating body (for example, a resistor) and a temperature sensor are arranged around the LED, and the heating body is driven, so that the desired environmental temperature can be set. Therefore, in FIG. 7, based on the result read by the photosensitive material information reading unit 30, the LED drive control unit 6 b may drive the heating body so as to reach a predetermined temperature. Such a temperature set value can be obtained by preparing a test print in advance. Thereby, the correction amount by the correction table described above can also be reduced.

<Method of gradation expression>
As a method of performing gradation expression, a method performed by adjusting the ON / OFF ON time in the liquid crystal shutter 21 and a method performed by a voltage applied to each pixel have been described. However, sufficient gradation expression may not be achieved with the liquid crystal shutter 21 alone. Therefore, when an LED is used as an exposure light source, the amount of light is adjusted by changing the current to the LED, and a sufficiently wide gradation expression is obtained by combining this light amount adjustment with the gradation expression by the liquid crystal shutter 21. It can be performed.

<Another embodiment>
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.

  As a modification of the embodiment shown in FIG. 4, 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 defined 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 Configuration example using LED as light source for exposure Configuration example using white LED as light source for exposure Example of combination of halogen lamp and color filter Diagram showing an example of the configuration to cope with the difference in photosensitive characteristics Diagram explaining the action of the filter

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 7 exposure engine (image exposure apparatus)
20 Halogen lamp 21 Liquid crystal shutter 22 Cylindrical lens 23 Rotating filter 23R Filter 23G Filter 23B Filter 25 LED
25R R-LED
25G G-LED
25B B-LED
26 White LED
26a LED chip

Claims (6)

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;
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. Pixel data dividing means for dividing pixel data for one pixel in accordance with the number of pixels in a pixel group arranged in the sub-scanning direction;
2. The image exposure apparatus according to claim 1, further comprising a shutter control unit that controls transmission and blocking of each pixel constituting the liquid crystal shutter according to the value of the divided pixel data.   3. The image exposure apparatus according to claim 1, wherein the exposure light source is configured by first color, second color, and third color LEDs for forming a color image. 4.   The image exposure apparatus according to claim 1, wherein the exposure light source is a white LED. A plurality of types of filters arranged in front of the LEDs and prepared according to the photosensitive characteristics of the image forming medium;
5. The image exposure apparatus according to claim 3, further comprising a filter switching mechanism that switches the filter in accordance with the type of the image forming medium.   The first, second, and third color filters for forming a color image are arranged on the front surface of the liquid crystal shutter, and the pixel group constituting the liquid crystal shutter is divided into regions corresponding to the respective colors. The image exposure apparatus according to claim 1, 2, or 4.

Images