WO2006004179A1

WO2006004179A1 - Exposure head and exposure equipment

Info

Publication number: WO2006004179A1
Application number: PCT/JP2005/012531
Authority: WO
Inventors: Yasuhiro Seto
Original assignee: Fuji Photo Film Co., Ltd.
Priority date: 2004-07-02
Filing date: 2005-06-30
Publication date: 2006-01-12
Also published as: JP2006015641A

Abstract

An exposure head is provided with a plurality of linear light emitting element arrays (6R, 6G, 6B). In each of the arrays, light emitting elements are arranged in parallel in one line, and the arrays are arranged in parallel in a direction substantially vertical to the direction wherein the light emitting elements are arranged, so as to emit beams of colors different from each other. The exposure head is also provided with one equal magnification lens array (7), which is composed of a plurality of lenses (7a), which collect the light emitted from the linear light emitting element arrays (6R, 6G, 6B) and are assembled in stagger arrangement substantially parallel to an arrangement direction of the light emitting elements, so as to collect the light of each color on a color photosensitive material. Among the plurality of linear light emitting element arrays (6R, 6G, 6B), the linear light emitting element array (6G) which emits light that exposes a coloring layer of the color photosensitive material having the highest relative luminosity is arranged closest to a long axis (L) of the equal magnification lens array (7). Thus, the color exposure head which does not generate much concentration nonuniformity due to light quantity fluctuation of exposure beams passed through the equal magnification lens array is provided.

Description

Exposure head and exposure apparatus

TECHNICAL FIELD The present invention relates to an exposure head using a plurality of types of line-shaped light emitting element arrays that emit light of different colors. Light

Thread 1

The present invention also relates to an exposure apparatus for exposing a color photosensitive material using the exposure head as described above. '

Background Art Conventionally, as shown in, for example, Japanese Patent Laid-Open No. 5-9 2 6 2 2 and Japanese Patent Laid-Open No. 2 0 0 0-1 3 5 7 1, each has different wavelength regions such as red, green and blue. An apparatus that exposes a color photosensitive material using an exposure head composed of a plurality of line-shaped light emitting element arrays that emit light of the same color is known. The above-described line-shaped light emitting element array is formed by arranging a plurality of light emitting elements such as organic EL (electric aperture luminescence) light emitting elements that emit light of the same color in a line. In the exposure head, a plurality of line-shaped light emitting element arrays emitting light of different colors are arranged side by side in a direction substantially perpendicular to the direction in which the light emitting elements are arranged, and the light emitted from each array is emitted. An equal-magnification lens array for condensing light is provided on the color photosensitive material. The exposure apparatus using such an exposure head holds a color photosensitive material at a position where light emitted from the exposure head is irradiated, and a plurality of the color photosensitive material and the exposure head are arranged. There is further provided sub-scanning means for relatively moving in the arrangement direction of the line-shaped light-emitting element arrays. It is configured.

In the above-mentioned equal-magnification lens array, a plurality of gradient index lenses that collect light emitted from the line-shaped light-emitting element array are substantially parallel to the longitudinal direction of the line-shaped light-emitting element array (light-emitting element arrangement direction). The force that is often used in the state of being assembled in a line is used. This type of lens array is quite expensive. The exposure head disclosed in Japanese Patent Laid-Open No. 5-9 2 6 2 2 is provided with a total of three such 1 × lens arrays, one for each of the three color line-shaped light emitting element arrays. Is expensive. In addition, when the same-size lens arrays are provided as many as the plurality of line-shaped light-emitting element arrays in this way, the width of the exposure head is usually increased because of the plurality of same-size lens arrays that are wider than the line-shaped light-emitting element arrays. This becomes an obstacle to downsizing the exposure apparatus.

On the other hand, in Japanese Patent Application Laid-Open No. 2 00 0-1 3 5 7 1, light emitted from each of a plurality of line-shaped light emitting element arrays is combined by a dichroic mirror, and one common magnification is obtained. An exposure head designed to be incident on the lens array is shown. However, such an exposure head requires only one equal-magnification lens array, but requires many other optical components, so there is still room for improvement in terms of cost and miniaturization. .

Therefore, it is also conceivable to directly combine one single-magnification lens array common to the three-color line-shaped light-emitting element array without performing the above-described multiplexing. However, in this case, there arises a problem that the amount of exposure light that has passed through the 1 × lens array varies greatly along the longitudinal direction of the lens array. This point will be described in detail below.

The above-described equal-magnification lens array is usually composed of a plurality of lens rows in which a plurality of lenses such as a gradient index lens are arranged in parallel in one direction and in a direction perpendicular to the lens arrangement direction. The adjacent lens rows are arranged so that the lens of another lens row enters the space between the lenses of one lens row. In other words, when you look at the whole, each lens is in a staggered arrangement It has become. When the light emitted from the line-shaped light-emitting element array is passed through such an equal-magnification lens array, the amount of exposure light that has passed through the long axis of the equal-magnification lens array (the central position of the lens array in the lens alignment direction) The lens arrangement pitch changes along the (extended axis).

For a line-shaped light-emitting element array that is aligned with the long axis of the equal-magnification lens array, that is, in a state where the optical axis of each light-emitting element intersects the long axis, the staggered array is arranged on both sides of the long axis. The variation in the amount of light is canceled out by the lens being used, so the variation in the amount of exposure is not so serious, but in the case of a line-shaped light-emitting element array arranged farther from the major axis, Since the effect of such cancellation becomes low, fluctuations in exposure become serious. If the amount of exposure fluctuates in this manner, naturally density unevenness occurs in an image exposed to a color photosensitive material. As described above, in an exposure apparatus that performs sub-scanning by relatively moving the color photosensitive material and the exposure head in the direction in which the plurality of line-shaped light emitting element arrays are arranged, if such density unevenness occurs, Therefore, streak unevenness S extending in the sub-scanning direction is generated, and the quality of the exposed image is greatly impaired.

The above describes the problems associated with the exposure head using an array of organic EL light-emitting elements. Self-luminous light-emitting elements other than organic EL light-emitting elements, and dimming elements such as liquid crystal and PLZT and light sources Of course, a similar problem can occur in an exposure head that uses an array of combined elements. In the present specification, an element composed of a combination of the above-described light control element and light source is also referred to as a “light emitting element” in the sense of an element that emits exposure light.

In view of the above circumstances, this object is to provide a color exposure head and an exposure apparatus that do not cause large density unevenness due to fluctuations in the amount of exposure light that has passed through the 1 × lens array. To do. Disclosure of the invention

The exposure head according to the present invention makes it difficult to visually recognize density unevenness caused by fluctuations in the amount of exposure light by setting the arrangement state of the plurality of line-shaped light emitting element arrays to a special state. In terms of

As described above, a plurality of line-shaped light-emitting elements that emit light of different colors, in which the light-emitting elements are arranged in a row, and are arranged in a direction substantially perpendicular to the direction of the light-emitting elements. An array,

A plurality of lenses for condensing light emitted from these line-shaped light emitting element arrays are gathered in a zigzag array so as to be arranged in parallel with the arrangement direction of the light emitting elements. In an exposure head equipped with a 1x lens array that focuses light on the photosensitive material,

Among the plurality of line-shaped light-emitting element arrays, the line-shaped light-emitting element array that emits light that sensitizes the coloring layer is the highest in the long axis of the equal-magnification lens array. It is characterized by being arranged in a close state.

In the exposure head of the present invention having the above configuration,

Of the multiple line-shaped light-emitting element arrays, the line-shaped light-emitting element array that emits the light that sensitizes the color-developing layer is the second most highly color-sensitive material, and the color-emitting layer that has the highest specific visual sensitivity. Located next to the line-shaped light emitting element array that emits light to be exposed,

When viewed from a direction parallel to the optical axis of the lens, the two adjacent linear light emitting element array forces S and the long axis of the equal-magnification lens array are placed between the two linear light emitting element arrays. It is desirable to arrange them separately.

In the exposure head of the present invention,

When the highest specific visibility and the second highest specific sensitivity are kk ₂ respectively, When viewed from a direction parallel to the optical axis of the lens, a line-shaped light-emitting element array that emits light that sensitizes the coloring layer having the highest relative visibility, and secondly, the high luminous efficiency and coloring layer. It is desirable that the ratio of the distance of the line-shaped light emitting element array that emits light from the long axis of the 1 × lens array is approximately: (l / k ₂ ).

In the exposure head of the present invention,

A plurality of linear light emitting element arrays that emit light of different colors emit light in the red, green, and blue wavelength regions,

It is desirable that the line-shaped light-emitting element array emitting light in the green wavelength region is disposed in the state closest to the long axis of the 1 × lens array among the three line-shaped light-emitting element arrays. Further, in the exposure head of the present invention, as the plurality of line-shaped light emitting element arrays that emit light of different colors, those composed of organic EL light emitting elements can be suitably used. On the other hand, an exposure apparatus according to the present invention provides:

An exposure head according to the invention as described above;

A color photosensitive material is held at a position irradiated with light emitted from the exposure head, and the color photosensitive material and the exposure head are relatively moved in the arrangement direction of the plurality of line-shaped light emitting element arrays. It is characterized by comprising scanning means.

The power-sensitive material is provided with a plurality of color layers, but the higher the relative visibility among these color layers, the more conspicuous the density unevenness caused by the fluctuation in the amount of exposure light. ing. In addition, due to the effect of canceling the light amount fluctuation of the equal magnification lens array described above, the light amount fluctuation is more as the light emitted from the line-shaped light emitting element array arranged near the long axis of the equal magnification lens array reaches the color photosensitive material. The smaller the light emitted from the line-shaped light emitting element array arranged farther from the major axis and reaching the color photosensitive material, the greater the variation in the amount of light.

In the exposure head of the present invention, paying attention to the above points, the most specific visual sensitivity of the color photosensitive material. The line-shaped light-emitting element array that emits light that sensitizes a high-quality color layer (that is, the color layer that is most conspicuous in density unevenness) is placed in the state closest to the long axis of the 1x lens array. It is possible to suppress the occurrence of density unevenness in the color developing layer with less. Since the other line-shaped light emitting element arrays are arranged farther from the long axis of the 1 × lens array, the light emitted from these line-shaped light emitting element arrays and reaching the color photosensitive material is more subject to fluctuations in the amount of light. However, since the color-developing layer that is sensitive to such light has a lower relative visibility, density unevenness due to exposure amount fluctuations in the color-developing layer is difficult to visually recognize.

Of the exposure heads of the present invention, in particular, as described above, among the plurality of line-shaped light-emitting element arrays, a line that emits light that sensitizes the second colorimetric layer of the color light-sensitive material having the highest visual sensitivity. The light emitting element array is arranged next to a line light emitting element array that emits light that sensitizes the coloring layer with the highest relative visibility, and is adjacent to the lens light emitting element array when viewed from a direction parallel to the optical axis of the lens. In an exposure head in which two linear light-emitting element arrays are arranged with the long axis of an equal-magnification lens array in between, the second color-developing layer (that is, the second) Occurrence of density unevenness in the coloring layer) where density unevenness is conspicuous is also reduced.

In addition, when the highest specific luminous sensitivity and the second highest specific luminous sensitivity are respectively set to k ₂ , the highest specific luminous sensitivity is obtained when viewed from a direction parallel to the optical axis of the lens! A line-shaped light-emitting element array that emits light that sensitizes the color-developing layer, and a line-shaped light-emitting element array that emits light that sensitizes the color-forming layer, which has the second highest relative visibility, from the long axis of the 1X lens array In an exposure head with a ratio of the sorting distances of approximately (1 1 ^): (l Z k ₂ ), the coloring layer with the highest relative visibility and the second high-viscosity coloring layer with the highest relative visibility are used. The degree of visibility of density unevenness can be suppressed to approximately the same level. Further, since the exposure apparatus of the present invention uses the exposure head having the above-described effects, it is possible to expose a high-quality image in which the occurrence of density unevenness due to fluctuations in the amount of exposure light is suppressed. -Brief description of the drawings

FIG. 1 is a partially cutaway front view of an exposure apparatus according to the first embodiment of the present invention.

FIG. 2 is a partially broken side view of the exposure apparatus.

FIG. 3 is a partial plan view showing the line-shaped light-emitting element array and the equal-magnification lens array in the exposure apparatus.

Figure 4 is a graph showing the standard relative luminous sensitivity characteristics of CIE (International Commission on Illumination).

FIG. 5 is a graph showing the relationship between the position of the line-shaped light emitting element array and the exposure amount deviation characteristic in the exposure apparatus.

FIG. 6 is a partial plan view showing the line-shaped optical element array and the equal-magnification lens array in the exposure apparatus according to the second embodiment of the present invention. .

FIG. 7 is a drawing showing the relationship between the position of the line-shaped light-emitting element array and the exposure deviation characteristic in the exposure apparatus according to the second embodiment.

FIG. 8 is a partial plan view showing a line-shaped light-emitting element array and an equal-magnification lens array in the exposure apparatus according to the third embodiment of the present invention.

FIG. 9 is a graph showing the relationship between the position of the line-shaped light emitting element array and the exposure amount deviation characteristic in the exposure apparatus according to the third embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a partially broken front shape of the exposure apparatus according to the first embodiment of the present invention, and FIG. 2 shows a partially broken side shape of the exposure apparatus. As shown in the figure, this exposure apparatus is configured to align the exposure head 1 and the color photosensitive material 3 held at the position where the exposure light 2 emitted from the exposure head 1 is irradiated in the direction indicated by the arrow Y in FIG. Sub-scanning means 4 composed of, for example, a nip roller is provided.

The exposure head 1 is arranged at a position to receive the organic EL panel 6 and the exposure light 2 emitted from the organic EL panel 6, and images the exposure light 2 on the color photosensitive material 3 at the same magnification. And a holding means 8 (not shown in FIG. 2) for holding the lens array 7 and the organic EL panel 6.

As shown in detail in the plan view of FIG. 3, the gradient index lens array 7 that is an equal magnification lens array has a minute gradient index lens 7 a that collects the exposure light 2 in the sub-scanning direction Y. A total of two lens rows are arranged in parallel in the main scanning direction (arrow X direction) perpendicular to. In the gradient index lens array 7, the gradient index lenses 7a are arranged in a staggered manner. That is, the plurality of gradient index lenses 7 a constituting one lens row are arranged so as to be positioned between the plurality of gradient index lenses 7 a constituting the other lens row.

The exposure apparatus according to the present embodiment, for example, exposes a color image to a color photosensitive material 3 that is a full-color positive type silver salt copying material, and the organic EL panel 6 constituting the exposure head 1 A red line light emitting element array 6 R, a green line light emitting element array 6 G, and a blue line light emitting element array 6 B arranged side by side in the running direction Y are provided. Each of these line-shaped light emitting element arrays 6 R, 6 G and 6 B is composed of a large number of red organic EL light emitting elements, green organic EL light emitting elements and blue organic EL light emitting elements arranged in parallel in the main scanning direction X. It is. In FIG. 1 and FIG. 2, one of the above-described light-emitting elements is typically shown as an organic EL light-emitting element 20. Each organic EL light-emitting element 20 is formed by sequentially depositing a transparent anode 21, an organic compound layer 22 including a light-emitting layer, and a metal cathode 23 on a transparent substrate 10 made of glass or the like. It will be. Then, red light emitting elements, green light emitting elements, and blue light emitting elements are respectively used as the light emitting layers, thereby forming red organic EL light emitting elements, green organic EL light emitting elements, and blue organic EL light emitting elements, respectively.

The line-shaped light emitting element arrays 6 R, 6 G, and 6 B are driven by a drive circuit 30 shown in FIG. That is, the drive circuit 30 is based on image data D indicating a full-color image of a cathode driver that sequentially sets the metal cathode 23 serving as a scanning electrode to an ON state at a predetermined cycle and a transparent anode 21 serving as a signal electrode. An anode driver that is set to an ON state is provided, and the line-shaped light emitting element arrays 6 R, 6 G, and 6 B are driven by a so-called passive matrix line sequential selection driving method. The operation of the drive circuit 30 is controlled by the control unit 31 that outputs the image data D.

Elements constituting each organic EL light emitting element 20 are arranged in a sealing member 25 made of, for example, a stainless steel can. That is, the edge of the sealing member 25 and the transparent substrate 10 are attached, and the organic EL light emitting element 20 is sealed in the sealing member 25 filled with dry nitrogen gas.

In the organic EL light emitting device 20 having the above configuration, when a predetermined voltage is applied between the metal cathode 23 and the transparent anode 21 extending across the metal cathode 23, the intersection of both electrodes to which H is applied Every minute, a current flows through the organic compound layer 22 and the light emitting layer contained therein emits light. This emitted light passes through the transparent anode 21 and the transparent substrate 10 and is emitted as exposure light 2 to the outside of the device. Here, it is preferable that the transparent anode 21 has a light transmittance of at least 50% or more, preferably 70% or more in the visible light wavelength region of 400 nm to 700 nm. Transparent sun As a material for the electrode 21, tin oxide, indium tin oxide (ITO), indium zinc oxide, etc., known compounds as transparent electrode materials are suitable: the ability to be able to contain M, and other high work functions such as gold and platinum A thin film made of metal may be used. In addition, organic compounds such as polyaniline, polythiophene, polypyrrole, or derivatives thereof can also be used. Supervised by Yutaka Sawada “New Development of Transparent Conductive Film” published by CMC Co., Ltd. (1 9 9 9) has a detailed description of transparent conductive film, and what is shown there is applied to the present invention. It is also possible. The transparent anode 21 can be formed on the transparent substrate 10 by a vacuum deposition method, a sputtering method, an ion plating method, or the like.

On the other hand, the organic compound layer 22 may have a single-layer structure composed of only a light emitting layer, or other layers such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer in addition to the light emitting layer. It may be a laminated structure having as appropriate. Specific layer configurations of the organic compound layer 22 and the electrode include an anode Z hole injection layer / hole transport layer / light emitting layer Z electron transport layer / cathode, and an anode / light emitting layer Z electron transport layer, cathode. Examples include an anode / hole transport layer, a Z light-emitting layer, a Z electron transport layer / a cathode, and the like. In addition, the light emitting layer, the hole transport layer, the hole injection layer, and the electron injection layer may each be provided with tVit number.

The metal cathodes 2 and 3 are made of low work functions such as alkali metals such as Li and K, an alkaline earth metals such as Mg and Ca, and alloys and mixtures of these metals with Ag and A1. Preferably formed from a metal material. In order to achieve both the storage stability and the electron ¾Λ property at the P electrode, the electrode made of the above material is further coated with Ag, Al, Au, etc. that have a high work function and high conductivity. Also good. The metal cathode 23 can also be formed by a known method such as a vacuum deposition method, a sputtering method, or an ion plating method, like the transparent anode 21.

The operation of the exposure apparatus having the above configuration will be described below. Here, the number of pixels in the main scanning direction of the line-shaped light emitting element arrays 6 R, 6 G and 6 B, that is, the transparent anodes 21 are arranged in parallel. Let n be the number. When the color photosensitive material 3 is subjected to image exposure, the color photosensitive material 3 is conveyed by the sub-scanning means 4 at a constant speed in the direction of arrow Υ. In synchronism with the conveyance of the color photosensitive material 3, one of the three metal cathodes 23 is sequentially turned on by the cathode driver of the driving circuit 30 described above.

In this manner, the anode driver of the drive circuit 30 is the first and second anodes within the period in which the first metal cathode 23, that is, the metal cathode 23 constituting the red line light emitting element array 6R is selected. N 2 transparent anodes 2 1 are connected to a constant current source for the time corresponding to the image data indicating the red density of the nth pixel on the 1st main scanning line 1, 2, 3 To do. As a result, a current having a pulse width corresponding to the image data flows through the organic compound layer 2 2 (see FIG. 1) between the transparent anode 21 and the metal cathode 2 3, and red light is emitted from the organic compound layer 22. Be emitted.

Thus, the exposure light 2 that is red light emitted from the red line-shaped light emitting element array 6 R is condensed on the color photosensitive material 3 by the lens array 7, and thereby the first main scanning on the color photosensitive material 3. The first, second, and third lines that make up the line are exposed to red light and develop red.

Next, within the period when the second metal cathode 23, that is, the metal cathode 23 constituting the green line-shaped light emitting element array 6G is selected, the anode driver of the drive circuit 30 is the first, second, 3 ■ ■ ■ n Each transparent anode 21 is connected to a constant current source for a time corresponding to the image data indicating the green density of the nth pixel of the first main scan line, 1, 2, 3. . As a result, a current with a Norse width corresponding to the image data flows through the organic compound layer 22 between the transparent anode 21 and the metal cathode 23, and green light is emitted from the organic compound layer 22.

Thus, the exposure light 2 which is green light emitted from the green line-shaped light emitting element array 6 G is condensed on the color photosensitive material 3 by the lens array 7, so that the first main scanning is performed on the color photosensitive material 3. The first, second, and third lines that make up the line When exposed, it turns green. Since the color photosensitive material 3 is conveyed at a constant speed as described above, the green light is irradiated onto a portion of the color photosensitive material 3 that has already been exposed to red light. ..

Next, within the period when the third metal cathode 23, that is, the metal cathode 23 constituting the blue line-shaped light emitting element array 6B is selected, the anode driver of the drive circuit 30 is the first, second, 3 ··· n transparent anodes 2 1 are connected to a constant current source for the time corresponding to the image data indicating the blue density of the nth pixel of the first main runner line To do. As a result, a current having a pulse width corresponding to the image data flows through the organic compound layer 22 between the transparent anode 21 and the metal cathode 23, and blue light is emitted from the organic compound layer 22.

In this way, the exposure light 2 which is the blue light emitted from the blue line-shaped light emitting element array 6 B force is condensed on the color photosensitive material 3 by the lens array 7, and thereby the first main light on the color photosensitive material 3. The first, second, and third lines that make up the scan line are exposed to blue light and develop blue. Since the color photosensitive material 3 is transported at a constant speed as described above, the blue light is irradiated onto the portion of the color photosensitive material 3 that has already been exposed to red light and green light. Through the above steps, the first full-color main scanning line is exposed and recorded on the color photosensitive material 3.

Next, the line-sequential selection of the metal cathodes returns to the first metal cathode 23, and the first metal cathode 23, that is, the metal cathode 23 constituting the red line light emitting element array 6R is selected. Within a certain period, the anode driver of the driving circuit 30 supplies each of the first, second, and third transparent anodes 21 to the first, second, and third nth pixels of the second main scanning line. Connect to a constant current source for a time corresponding to the image data indicating the red density of the. As a result, a current having a pulse width corresponding to the image data flows through the organic compound layer 22 between the transparent anode 21 and the metal cathode 23, and red light is emitted from the organic compound layer 22. Thus, the exposure light 2 which is red light emitted from the red line-shaped light emitting element array 6 R is condensed on the color photosensitive material 3 by the lens array 7, so that the second main scanning is performed on the color photosensitive material 3. The 1st, 2nd, 3rd, 3rd, and nth pixels that make up the line are exposed to red light, and develop a red color.

In the following, the same operation is repeated to expose the second full-color main scanning line, and then such color main scanning lines are exposed side by side in the sub-scanning direction Y one after another. A two-dimensional color image consisting of the main scan lines is exposed. In this embodiment, as described above, each color exposure light is subjected to pulse width modulation, and the amount of emitted light is controlled corresponding to the image data, thereby exposing a single gradation image.

Next, a configuration for preventing the occurrence of density unevenness due to the above-described fluctuation in the amount of exposure light will be described in detail. In the present embodiment, the diameter of each gradient index lens 7 a of the gradient index lens array 7 is 2 95 m. As shown in FIG. 3, the green line-shaped light emitting element array 6G is the long axis L of this gradient index lens array 7 (the axis extending from the center position of the two lens rows in the direction in which the lenses 7a are arranged) Red line-shaped light emitting element array 6 R and blue line-shaped light emitting element array 6 B are arranged at intervals of Ι Ο Ο μm in the sub-scanning direction Y, respectively. .

In general, human relative luminous sensitivity for the three primary colors R, G, and B is defined as 6 10 nm, 5 nm for each wavelength, as indicated by the CIE (International Commission on Illumination) standard relative luminous sensitivity. When it is 60 nm and 470 nm, it is about 3: 6: 1. Figure 4 shows the CIE standard relative luminous sensitivity characteristics. In this figure, the density unevenness that occurs in the full-color image formed on the color photosensitive material 3 is caused by moving the power photosensitive material 3 in the sub-scanning direction in this example, and thus extends in the sub-scanning direction. Appears as an irregular muscle. The visibility of the stripe unevenness is proportional to the specific visual sensitivity. Specifically, B color is difficult to see even if there is a slight density difference, but G color is small. Even density differences are becoming more visible as unevenness. In other words, the ratio of the permissible values of the light intensity deviation for each of R, G, and B is the ratio of the reciprocal of the above-mentioned specific luminous sensitivity. If the permissible value of the G light intensity deviation is 1, R: G: Β = · 2 : 1: 6 Therefore, when the G light intensity deviation is within the allowable value, the light intensity deviation of R and dark blue is allowed to be twice and 6 times the light intensity deviation of G color, respectively.

Here, as described above, when the exposure light 2 emitted from the line-shaped light emitting element arrays 6 R, 6 G, and 6 B is passed through the gradient index lens array 7, the amount of the exposure light 2 that has passed is Then, along the major axis L of the refractive index distribution type lens array 7, the arrangement pitch of the lens 7a changes with the period. Such fluctuations in the amount of light cause the above-described density unevenness. The periodic deviation of the exposure light 2 changes in accordance with the distance from the long axis L of the linear fluorescent element array 6R, 6G, or 6B, as shown in the curve of the actual measurement result in FIG. The above distance is a distance when viewed from a direction parallel to the optical axis of the lens 7a (hereinafter the same), and is referred to as an “optical axis offset”.

With regard to the direction of this optical axis offset, if the downward direction from the major axis L is defined as + and the upward direction is defined as one in FIG. 3, the optical axis offsets of the line-shaped light emitting element arrays 6 R, 6 G, and 6 B are shown in FIG. As shown. In other words, as is clear from the above explanation, the optical axis offset of the green line-shaped light emitting element array 6G is 0 (zero), and the red line light emitting element array 6R and the blue line light emitting element array 6B The optical axis offset is 1100 ^ m and + 100 / zm, respectively. When the optical axis offset is such a value, the light intensity period deviation of each color exposure light of R, G, and B is R = 0.94%, G = 0.52%, B = 0.94% . A value of 0.52% of the light amount period deviation of the G-color exposure light 2 is a preferable value in general that density unevenness is not visually recognized. The ratio of these light intensity period deviations is R: G: B = 1.8: 1: 1.1.8, and the light intensity period deviation of the R light and B exposure light 2 is G light. The above-mentioned conditions of 2 times and 6 times the quantity deviation are satisfied.

As described above, in the present embodiment, the green line-shaped light emitting element array 6 G that emits the exposure light 2 that develops the G color that is most conspicuous in density unevenness is positioned at the optical axis offset = 0 where the light amount period deviation is minimized. In other words, by arranging it at a position that aligns with the long axis L of the gradient index lens array 7, the visibility of the density unevenness of the G color is minimized, while the line-shaped light emitting element arrays 6 R and 6 By arranging B at the above position, the visibility and performance of the density unevenness of the R and B colors can be kept very low.

Next, an exposure apparatus according to the second embodiment of the present invention will be described. The exposure apparatus of the second embodiment differs from the exposure apparatus of the first embodiment in the relative positional relationship between the linear light emitting element arrays 6 R, 6 G, and 6 B and the gradient index lens array 7. Other points are basically the same.

FIG. 6 is a plan view showing the relative positional relationship between the linear light-emitting element arrays 6 R, 6 G and 6 B and the gradient index lens array 7 in the exposure apparatus of the third embodiment. As shown here, in this embodiment, the order of the line-shaped light-emitting element arrays 6R, 6G, and 6B is the same as that of the first embodiment, and the central green-line light-emitting element array 6G is Similar to the first embodiment, it is arranged at a position aligned with the long axis L of the gradient index lens array 7, but in the sub-scanning direction Y of the three linear light emitting element arrays 6R, 6G and 6B. Unlike the first embodiment, the self-placement interval is 1 6 0 // m. The diameter of each gradient index lens 7a of the gradient index lens array 7 is 2 9 5 // m.

FIG. 7 shows the light amount period deviation characteristic of the exposure light 2 similar to that shown in FIG. 5 together with the optical axis offsets of the line-shaped light emitting element arrays 6 R, 6 G, and 6 B in the present embodiment. Is. When the optical axis offset is the value of this embodiment, the light amount period deviation of each of the R, G, and B color exposure lights 2 is R = l. 87%, G = 0.5 2%, B = l. 8 7%. even here, The light amount period deviation of the G-color exposure light 2 is normally suppressed to 0.52%, which is preferable from the viewpoint that density unevenness is not visually recognized. As described above, even in this embodiment, the green line-shaped light emitting element array 6 G that emits the exposure light 2 that develops the G color that is most conspicuous in density unevenness is aligned with the long axis L of the gradient index lens array 7. As a result, the visibility of G density unevenness is very low.

If the ratio of the light intensity period deviations of R, G, and B exposure light 2 is calculated, R: G: B = 3.6: 1: 3.6 is obtained. The above condition of up to 6 times is satisfied, but the condition of up to twice the light intensity deviation of the G color is not satisfied for the R color. This problem can be solved by a third embodiment described below. Hereinafter, an exposure apparatus according to the third embodiment of the present invention configured as described above will be described. The exposure apparatus of the third embodiment differs from the exposure apparatus of the second embodiment in the relative positional relationship between the line-shaped light emitting element arrays 6R, 6G, and 6B and the gradient index lens array 7. The other points are basically formed in the same manner.

FIG. 8 is a plan view showing the relative positional relationship between the line-shaped light emitting element arrays 6 R, 6 G and 6 B and the gradient index lens array 7 in the exposure apparatus of the third embodiment. As shown here, in this embodiment, the order of the line-shaped light-emitting element arrays 6 R, 6 G, and 6 B is the same as that of the second embodiment, and the three line-shaped light-emitting element arrays 6 R, 6 G are arranged. Similarly, the arrangement interval in the sub-scanning direction Y of B is also 1600 μm, but the central green line-shaped light emitting element array 6 G is not directly above the long axis L of the gradient index lens array 7 From there, it is placed at + 60 μ πι. The refractive index distribution lens 7a of the gradient index lens array 7 has a diameter of 29 5 im.

FIG. 9 shows the periodic deviation characteristics of the exposure light 2 similar to that shown in FIG. 5 together with the optical axis offsets of the line-shaped light emitting element arrays 6 R, 6 G, and 6 B in the present embodiment. The When the optical axis offset is the value of this embodiment, the light quantity period deviations of the R, G, and B color exposure lights 2 are R = 0.94%, G = 0.68%, B = 3.20%. Become. When these ratios are calculated, R: G.: B = 1.4: 1: 4.7, and the light intensity period deviation of R and B exposure light 2 is twice the light intensity deviation of G color each. The above-mentioned condition of up to 6 times is satisfied. As described above, in the present embodiment, the green line-shaped light emitting element array 6 G that emits the exposure light 2 that develops the G color that is most conspicuous in density unevenness is positioned closest to the long axis of the gradient index lens array 7 and positioned. In other words, the red line-shaped light emitting element array 6R that emits the exposure light 2 that emits the R color, which is the second most conspicuous in density unevenness, is arranged at a distance of 60 μm, the length of the refractive index distribution lens array 7 By arranging the axis L force at a position 100 tm away, the visibility of density unevenness of G and R colors can be kept low, while the blue line-shaped light emitting element array 6 B is By arranging it at the position, the visibility of density unevenness of B color is also kept low. In each of the embodiments described above, the relationship between the optical axis offset of the linear light emitting element arrays 6 R, 6 G, and 6 B with respect to the long axis L of the gradient index lens array 7 and the light amount period deviation of the exposure light 2 is It is assumed that it is known in advance. However, when the characteristics of the same-size lens array used and the intervals between multiple line-shaped light-emitting element arrays differ for each type of exposure apparatus, the relationship between the optical axis offset and the light amount period deviation for each model Measuring this requires a lot of effort and is not realistic.

Therefore, it is assumed that the increase in the light amount deviation is linear in the range from the major axis L of the gradient index lens array 7 to the same distance as the diameter of the lens 7a. By setting each distance to the G and red line light-emitting element array 6 R to a value that is inversely proportional to the relative visibility of the G and R colors, the density unevenness of both the G and R colors can be reduced. be able to.

More specifically, when the specific luminous sensitivity of G color is k _{1 and} the specific luminous sensitivity of R color is k ₂ , These ratios are: k ₂ = 6: 3 and the ratio of the reciprocal 1: 2. Therefore, when the distance between the green line-shaped light emitting element array 6 G and the red line-shaped light emitting element array 6 R is 160 μm, the green line-shaped light is emitted from the long axis L of the gradient index lens array 7. The distance to the element array 6 G may be set to 53 μ μη, and the distance from the long axis L to the red line light emitting element array 6 R may be set to 10. The density unevenness of the G and R colors in this case is determined by measuring the relationship between the optical axis offset of the line-shaped light emitting element arrays 6R and 6G and the exposure light quantity deviation, and On the basis of this, the density unevenness when the optical axis offset of the line-shaped light emitting element arrays 6 R and 6 G is determined is only slightly different.

As described above, an exposure apparatus that generates light of three colors, red light, green light, and blue light, from the exposure head, and sensitizes the red color development layer, the green color development layer, and the blue color development layer of the color photosensitive material 3 with these lights, respectively. However, the present invention can also be applied to an exposure apparatus that targets a power-sensitive material having a color-developing layer that emits other colors. There is an effect.

In each of the embodiments described above, the gradient index lens array 7 in which the gradient index lens 7 a has a diameter of 29 5 μm is used, but the diameter of the equal magnification lens array is set to that value. Of course, it is not limited, and the arrangement interval between the plurality of line-shaped light-emitting elements and the line-shaped light-emitting element array that emits light that sensitizes the coloring layer having the highest relative visibility of the color light-sensitive material The distance from the long axis of the 1 × lens array is not limited to the value in each of the embodiments described above.

In the above embodiment, an organic EL light emitting element is used as a light emitting element constituting the line-shaped light element array. However, the present invention configures a line-shaped light emitting element array from other light emitting elements such as a light emitting diode. In addition, it is not limited to self-luminous light emitting elements such as organic EL light emitting elements, but is a combination of a light control element such as a liquid crystal or PLZT and a light source. The present invention can also be applied to the case where a line-shaped light emitting element array is configured by using a combination of elements. In this case, the same effect can be obtained.

Further, the exposure apparatus of the above embodiment is for exposing the image to the color photosensitive material 3 which is a full-color positive type silver salt photographic photosensitive material, but the exposure apparatus of the present invention is for exposing the image to other color photosensitive materials. It is also possible to form as.

Claims

The scope of the claims

1. A plurality of line-shaped light-emitting element arrays each emitting light of different colors, each having light elements arranged side by side in a line, and arranged side by side in a direction substantially perpendicular to the direction of the light-emitting elements. A plurality of lenses for condensing light emitted from these line-shaped light emitting element arrays are gathered in a staggered arrangement so as to be arranged substantially in parallel with the arrangement direction of the light emitting elements. In an exposure head equipped with a 1 × lens array focused on a photosensitive material,

Among the plurality of line-shaped light-emitting element arrays, the line-shaped light-emitting element array that emits light for sensitizing the color-developing layer having the highest relative visibility of the power-sensitive material is in a state closest to the long axis of the 1 × lens array An exposure head characterized by being arranged in

2. Of the plurality of line-shaped light-emitting element arrays, the line-shaped light-emitting element array that emits light that sensitizes the coloring layer having the second highest visual sensitivity of the light-sensitive material is the highest in the relative visual sensitivity. It is placed next to the line-shaped light-emitting element array that emits light to sensitize the coloring layer,

When viewed from a direction parallel to the optical axis of the lens, the two adjacent linear light emitting element arrays are arranged with the long axis of the equal-magnification lens array placed between the two linear light emitting element arrays. The exposure head according to claim 1, wherein the exposure head is arranged.

3. When the highest specific luminous sensitivity and the second highest specific luminous sensitivity are k ₂ , respectively, when viewed from a direction parallel to the optical axis of the lens, the highest specific luminous sensitivity! / A line-shaped light-emitting element array that emits light that sensitizes the coloring layer and a line-shaped light-emitting element array that emits light that sensitizes the second colorimetric layer with the highest visual sensitivity are swung from the long-axis lens array long axis. 3. The exposure head according to claim 2, wherein the ratio of the dividing distance is approximately (11): (l / k ₂ ).

4. The plurality of line-shaped light emitting element arrays emitting light of different colors emit light in the red, green and blue wavelength regions, respectively.

A line-shaped light-emitting element array that emits light in the green wavelength region is arranged in a state closest to the long axis of the equal-magnification lens array among the three line-shaped light-emitting element arrays. The exposure head according to any one of claims 1 to 3.

5. The exposure head according to claim 1, wherein the plurality of line-shaped light-emitting element arrays emitting light of different colors are composed of organic EL light-emitting elements. ,.

6. The exposure head according to claim 1, wherein the power of the first claim is 4 times, and the deviation is 1;

A color photosensitive material is held at a position where light emitted from the exposure head is irradiated, and the color photosensitive material and the exposure head are relative to each other in the arrangement direction of the plurality of line-shaped light emitting element arrays. An exposure apparatus comprising sub-scanning means to be moved and power.