JPH11170606A - Method for adjusting light intensity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for adjusting a light intensity whereby a variance in image exposure by an image-exposing apparatus is restricted. SOLUTION: In a test image-exposing apparatus of the same structure as an image-exposing apparatus, a test photosensitive film is exposed in a thin-out manner separately by a first group G1 of light beams of odd-number channels and a second group G2 of even-number channels among channels C1-C120 of an LED array. A width of each scan line of the obtained image is measured by a line width-measuring apparatus, and a correction coefficient for each channel corresponding to a maximum, a minimum basic current value is obtained from the widths. Thereafter, the test photosensitive film is exposed similarly in the thin-out manner by the image-exposing apparatus as a product. Each scan line width is measured. An optimum current value for each channel is calculated from the scan line widths and correction coefficients to uniform the scan line widths, and set the value to the image-exposing apparatus. The process is conducted to each image-exposing apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light intensity adjusting method for adjusting the intensities of a plurality of light beams in an image exposure apparatus for scanning and exposing a photosensitive material with a plurality of light beams.

[0002]

2. Description of the Related Art A conventional multi-channel type image exposure apparatus is provided with a plurality of light-emitting elements (channels) such as LEDs, and simultaneously irradiates a photosensitive material with a light beam to simultaneously perform a plurality of scanning operations. While exposing an image to a photosensitive material, there is a problem in that if there is a variation in the scanning line width for each channel, the image will be uneven for each scanning line having a large line width, thereby deteriorating the image quality.

In order to solve this problem, Japanese Patent Laid-Open Publication No. 7-31
In the apparatus disclosed in Japanese Patent No. 9086, the light intensity of each channel is individually measured by a light intensity distribution measuring means for measuring the light intensity of each channel, and the light intensity of each channel is adjusted based on the measured light intensity to measure each scanning line width. Is made constant.

[0004]

By the way, in the apparatus as described above, even if the photosensitive material is not exposed by direct beam irradiation (hereinafter referred to as "main exposure"),
Exposure by beam irradiation in other parts (hereinafter referred to as “sub-exposure”) occurs, and even if the light emission amount of each channel is individually adjusted, the thickness of each scanning line varies due to the influence of the sub-exposure by other channels. There was a problem that occurs.

In general, photosensitive materials have the characteristic that the sensitivity differs depending on the order of main exposure and sub-exposure. That is, the sensitivity of the photosensitive material differs depending on whether sub-exposure is received before main exposure or sub-exposure after main exposure, and the exposure result is also different. In the photosensitive material used in the image exposure apparatus as described above, the influence of the sub-exposure of the later exposure acts more strongly on the scanning line which is relatively main-exposed earlier, and the scanning line width is increased due to excessive exposure. There is also a problem that the thickness of each scanning line varies as a result.

An object of the present invention is to overcome the above-mentioned problems in the prior art, and an object of the present invention is to provide a light intensity adjusting method for suppressing unevenness in image exposure by an image exposure apparatus.

[0007]

According to a first aspect of the present invention, there is provided an image exposure apparatus for scanning and exposing a photosensitive material with a plurality of light beams. A light intensity adjustment method for adjusting the intensity, comprising: a group of light beams that are not geometrically adjacent to each other as one subgroup; a classifying step of classifying a plurality of light beams into a plurality of subgroups; Exposure process for exposing the photosensitive material by irradiating each of the sub-groups, a measuring process for measuring the exposure condition of the test photosensitive material, and adjusting respective intensities of the plurality of light beams based on the measured exposure condition. Adjusting step.

According to a second aspect of the present invention, there is provided the light intensity adjusting method according to the first aspect, wherein the exposing step comprises the steps of: It is characterized by the step of sequentially exposing the photosensitive material.

According to a third aspect of the present invention, there is provided the light intensity adjusting method according to the second aspect, wherein the plurality of sub-groups include every other light beam among the plurality of light beams. Is a set of

According to a fourth aspect of the present invention, there is provided the light intensity adjusting method according to the third aspect, wherein the measurement of the exposure state is performed by a plurality of scans by each light beam of a plurality of subgroups. It is a measurement of the line width of the line, and the adjustment process is
The method is characterized in that the light emission intensity of each light beam is adjusted so that the line width of the plurality of scanning lines becomes equal to the common target line width in the plurality of subgroups.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <1. Apparatus Configuration> FIG. 1 is a view showing a schematic configuration of an image exposure apparatus according to an embodiment of the present invention. Hereinafter, the image exposure apparatus 1 will be described with reference to FIG.

This image exposure apparatus is an image exposure apparatus 1 (hereinafter referred to as "image exposure apparatus 1") which is actually shipped to the market as a product.
Alternatively, it is referred to as “image exposure apparatus 1 as a product”. )When,
It has the same structure as the main part described below,
The test image exposure apparatus 2 used only in a correction coefficient calculation process described later is included.

The image exposure apparatus rotates the rotary drum 20 around which the photosensitive film F (including a photosensitive film F for actual image exposure and a test photosensitive film F to be described later) is wound by the rotation of the main scanning motor 10, and a multi-layered drum. Image exposure is performed on the photosensitive film F by spiral scanning (or step scanning) with a plurality of exposure beams irradiated by the beam head 30.

The multi-beam head 30 in this image exposure apparatus has an LED (light emitting diode) array 31.
And an imaging lens system 32 capable of zooming. FIG. 2 is a diagram showing a schematic configuration of the LED array 31 of the image exposure apparatus. As shown in the figure, the LED array 31 is composed of a total of 120 LED elements which are arranged with their positions shifted from each other at four periods, and each element has channels C1 to C
120 are associated with each other. Each of these channels C1 to C120 can simultaneously expose 120 scanning lines to the photosensitive film F as an exposure beam.

As shown in FIG. 1, the multi-beam head 30 is screwed into a feed screw TS formed on a sub-scanning shaft 40 provided in parallel with the rotation axis of the rotary drum 20. The sub-scanning shaft 40 is rotated by the sub-scanning motor 50 in which the screw TS is attached to the rotating shaft, whereby the multi-beam head 30 is sent parallel to the rotating shaft of the rotating drum 20 (sub-scanning direction), whereby sub-scanning is performed. Done.

The control unit 60 has a memory and a CPU inside, and is electrically connected to a touch panel 61 for inputting an instruction. Further, the control unit 60
The LED array electrically connected to the main scanning motor 10 and the sub-scanning motor 50 while capturing the main scanning position and the sub-scanning position based on signals from encoders provided in the sub-scanning motor 50. 31 performs ON / OFF control of each channel at a predetermined timing, and
The image is exposed on the photosensitive film F attached to the outer peripheral surface of the.

FIG. 3 is a diagram showing a schematic configuration of the line width measuring device 3 according to the embodiment of the present invention.

In the line width measuring device 3, the document table 15
A developed test photosensitive film F exposed by the image exposure device 1 or the test image exposure device 2 is placed on the upper portion, and when a transmission light source 25 provided below the document table 15 is turned on, the light is emitted therefrom. The obtained light is the photosensitive film F for testing.
, And is imaged by the imaging lens 35 on the two-dimensional CCD camera 45 provided above the imaging lens. The exposure image on the test photosensitive film F formed on the two-dimensional CCD camera 45 is converted into an electric signal there and stored in the image memory 55 as described later.

Further, the image data stored in the image memory 55 is provided with an instruction input means such as a mouse 65 and a keyboard 75 and a graphic display 85, and is read out by a computer 95 having a memory and a CPU as necessary. , The following processing and calculation are performed.

<2. Processing and Effect> FIGS. 4, 5 and 6 are flowcharts respectively showing the procedures of the entire light emission intensity adjustment processing, correction coefficient calculation processing and optimum current value setting processing in this embodiment. Hereinafter, FIGS. 4 to 6
Will be described with reference to FIG.

In the emission intensity adjustment processing, first, a correction coefficient calculation processing is performed (FIG. 4: step S1). The correction coefficient is a value used to correct the current value so that the exposure line width based on the initial current becomes the target line width, and is obtained from the relationship between the current change amount and the line width change amount. In this case, LED
Using a film exposed with a basic driving current and a current slightly different from the basic current, the correction coefficient is determined for the maximum and minimum basic current values used for exposure. Therefore, the exposure of the film is performed using the basic current value and current values slightly different from the basic current value, that is, four types of current values.
This correction coefficient calculation is performed as follows.

First, in the test image exposure apparatus 2, the operator sets the maximum and minimum basic current values used for exposure through the touch panel 61 (FIG. 5: step S1).
0). As a result, the two types of basic current values are stored in the memory in the control unit 60.

Next, the worker attaches the test photosensitive film F to the rotating drum 20 of the test image exposure apparatus 2 (FIG. 5: step S11). This test photosensitive film F
Is a photosensitive film of exactly the same type as the photosensitive film F for performing image recording by an image exposure device as a product, and the film used for the light emission intensity adjustment processing is simply called a test photosensitive film F.

The image exposure apparatus 1 is capable of performing image exposure on various kinds of photosensitive films F. Therefore, the test image exposure apparatus 2
However, the following processing is performed on various kinds of test photosensitive films F of the same type, thereby adjusting the emission intensity of each channel C1 to C120 of the LED array 31 in the image exposure apparatus 1 described later. It can be adapted to the characteristics of the photosensitive film F.

Next, in the test image exposure apparatus 2,
Thinning exposure is performed using the minimum basic current value of the two types of basic current values (FIG. 5: step S12).

According to the present invention, of the light beams from all the light sources in the image exposure apparatus 1 and the test image exposure apparatus 2, a set of light beams that are not geometrically adjacent to each other (actually, a set of each channel) is used. As one subgroup, it is classified into a plurality of subgroups. In addition,
Here, the term “adjacent” refers to the nearest one on each side of a specific light beam, and in terms of a channel, indicates whether the channel number (the number after the reference symbol C) is larger or smaller by “1”. I have.

In particular, in this embodiment, as shown in FIG. 2, the light beam from the odd-numbered channel of each of the channels C1 to C120 of the image exposure apparatus 1 is first transmitted.
The second group G2 is a group G1 and a light beam of an even number of channels is independently illuminated, thereby performing a thinning exposure for exposing every other scanning line to the test photosensitive film F.

FIG. 7 shows each channel C in the thinning exposure.
It is a figure for explaining the exposure order by 1-C120. In the figure, the circles with the numbers represent the positions of the light beams in the sub-scanning direction by the respective channels. 7 (a) and 7 (b) represent light beams of the first group G1 and the second group G2, respectively. In the thinning exposure, one test photosensitive film F is used. Is exposed by irradiating all the light beams of the first group G1 and exposing all the light beams of the second group G2 to another test photosensitive film F. In this thinning exposure, 1
Except for forming every other scan line, the scan line is formed by spiral scanning in the same relative position and order as when an image is exposed on the photosensitive film F by the image exposure apparatus 1 as a product. Note that an example of the scanning line is shown in FIG.
Is shown in

That is, as shown by hatching in FIG. 7A or FIG.
While irradiating all the light beams of the first or second group G2,
The main scanning is performed by the rotation of the rotary drum 20, and the multi-beam head 30 moves in the sub-scanning direction along with the main scanning. Then, when the rotating drum 20 makes one rotation,
The next scanning line is formed adjacent to the positive side in the sub-scanning direction.

Each of the channels C1 to C120 shown in FIG.
The numbers shown above indicate the order in which each scan line is exposed. Here, the same numbers indicate that the light emission is performed at the same timing by parallel light emission. That is, as shown in FIG. 2, the LED elements are arranged with their positions shifted from each other in the main scanning direction at a period of four.
For example, when exposing all the channels of the first group, the channels C1, C5, C9,.
After the exposure of C117 is started and the sub-exposure of the first column is performed, the channels C3, C3,
Exposure of C7, C11,..., C119 is started.

As described above, in this embodiment, every other scanning line is exposed to correct the influence of the sub-exposure between the light beams by the respective channels as described below. However, there is a following reason why every other is selected.

When the scanning lines exposed by the adjacent light beams, that is, the exposed scanning lines are in contact with each other, the scanning lines are not separated and the width of each scanning line cannot be measured. However, when exposing every other scanning line, it receives weak exposure due to exposure from neighboring channels,
This affects the scanning line width due to the sub-exposure effect. Therefore, in order to accurately capture the influence of such weak sub-exposure, such channels are classified into a first group G1 and a second group G2, and every other exposure is separately performed. .

Next, the operator develops the test photosensitive film F subjected to the thinning-out exposure (FIG. 5: step S1).
3).

Next, the operator causes the line width measurement device to read the image on the test photosensitive film F subjected to the thinning exposure (FIG. 5: step S14). Specifically, the worker places the test photosensitive film F on which the thinning-out exposure has been performed on the platen 15 of the line width measuring device 3 and gives an instruction to read an image to the computer 95 by using the mouse 65 or the keyboard 75. To read the thinned exposure image recorded on the test photosensitive film F.

FIG. 8 is a diagram showing an example of an enlarged image of the thinned exposure image read by the line width measuring device (FIG. 8A).
FIG. 8 is a diagram showing a transmittance distribution obtained on the basis of FIG.
(B)), and in these figures, an example of thinning exposure by the first group G1 is shown. The line width measuring device 3 captures a thinned exposure image as shown in FIG. 8A as a digital signal divided into a large number of pixels by each CCD element of the two-dimensional CCD camera 45 and stores it in the image memory 55.

Next, the operator calculates the transmittance distribution of each scanning line using the line width measuring device (FIG. 5: step S1).
5).

As shown in FIG. 8A, each of the channels C1 to C in the read thinned exposure image is read.
120 (channels Cn, Cn + 2, Cn +
4, Cn + 6) (scan lines Ln, Ln + 2, Ln + 4, Ln + 6 corresponding to channels Cn, Cn + 2, Cn + 4, Cn + 6 in the figure) have different thicknesses. In order to numerically capture the scanning line width of such a scanning line, the line width measuring device 3 obtains the transmittance of each pixel of the thinned exposure image obtained as shown in FIG. At each pixel position in the sub-scanning direction in the main scanning direction (the length direction of the scanning line). Here, the reason why the transmittance is added in the length direction of the scanning line is that the scanning line generally has a slightly different line width depending on the position in the length direction. This is because the error increases, and the error is suppressed.

Next, the operator measures the scanning line width of each channel based on the obtained transmittance distribution by the line width measuring device (FIG. 5: step S16).

In this embodiment, as shown in FIG. 8B, in order to numerically detect the scanning line width, the obtained transmittance of each of the channels C1 to C120 is set to a predetermined threshold value. The distance between pixel positions (that is, the interval between pixel positions where the threshold value intersects the graph of the transmittance distribution of each channel) is determined by the width of each scanning line (the scanning lines Ln, Ln + 2 in the figure).
Scan line widths Wn, Wn + corresponding to Ln + 4, Ln + 6
2, Wn + 4, Wn + 6).

Such a scanning line width is obtained for the scanning lines by the channels C1 to C120 in each of the thinned exposure images.

The scanning line width obtained here is the scanning line width affected by the sub-exposure by the light beams of the neighboring channels C1 to C120 in the subgroup.

The channels at the ends of the channels C1 to C120, that is, channels C1, C2,.
Since the scanning lines formed by the channels C119 and C120 have a relationship in the order of exposure between neighboring or adjacent scanning lines, the scanning line width is affected by the difference in sensitivity of the photosensitive film F due to the order of sub-exposure. I have.

Channels C1 to C120 are LEDs
When the rotating drum 20 rotates while being exposed with a delay time corresponding to the element dislocation arrangement, for example, the channel C
No. 2 scans the position adjacent to the scanning line by the adjacent channel C1 with a slight delay by the shift amount of the shift arrangement. This is because four LEDs, such as between channels C2 and C3 and between channels C3 and C4,
A similar situation occurs with one cycle of the element. Therefore, the light beams exposing those scanning lines cause sub-exposure to each other, and as described above, in the photosensitive film F and the test photosensitive film F used in the image exposure apparatus 1 and the test image exposure apparatus 2, There is a tendency that the sensitivity of the scanning line position after the main exposure is higher than that of the scanning line position after the main exposure. This is the same in the thinning exposure, as shown in FIG.
Now, the channels Cn, Cn + 4, Cn + exposed earlier
, The scanning line width by channels Cn + 2, Cn + 6, Cn + 10,... Exposed later is small. As described above, since the exposure is also performed in the same order as in the actual image exposure in the thinning exposure, the image obtained by the exposure is different in the sensitivity of the photosensitive film F due to the order of the main exposure and the sub-exposure as described above. The effect is included.

If the processing in steps S11 to S16 for all the current values has been completed, the process proceeds to the next step S18. If not, the processing in steps S11 to S16 is performed according to the remaining current values. Is repeated (FIG. 5: step S17).

When the processing with all the current values has been completed, the operator sets each of the measured channels C
A correction coefficient for the maximum or minimum basic current value is determined based on the scanning line width of each of the channels C1 to C120.
It is calculated every time and stored by any storage means (FIG. 5: step S18).

Next, a method of calculating the correction coefficient A based on the basic current value will be described.

FIG. 9 shows the channels Cn, Cn + 2, Cn + 4, Cn + 6 (n is 1) exposed with a minimum basic current value of 2.5 mA and a slightly different current value of 3.5 mA.
Any integer from ~ 120. The same applies hereinafter. FIG. Here, the correction coefficient A is defined by the following equation.

Correction coefficient A = Target scanning line width × Current change amount / Scan line width change amount Expression 1 The correction coefficient A is set for each of the above-described maximum and minimum basic current values for each of the channels C1 to C120. The difference is obtained as follows.

First, the scanning line width variation, which is the difference between the minimum basic current value and the scanning line width due to a slightly different current value, is determined. In the example of the channel Cn in FIG. 9, the current value is 3.5.
The measured scan line width at mA and 2.5 mA was 7.
Since they are 0 μm and 4.0 μm, the scanning line width change amount is 3.0 μm.

The amount of change in the current was 2.5 mA and 3.5.
It is 1.0 mA because it is a difference from mA.

The target scanning line width is a predetermined scanning line width suitable for each resolution, and includes all the channels C 1 to C 1 of the test image exposure apparatus 2 and the image exposure apparatus 1 as each product. It has a common value for the scanning line by the light beam of C120. Therefore, the values are naturally common to the scanning lines by the light beams of the respective channels of the first and second groups G1 and G2.

Then, the obtained scan line width change amount, current change amount, and a predetermined target scan line width common to the test image exposure apparatus 2 and each channel (5.0 μm in the example of FIG. 9).
m), the correction coefficient A is obtained using Expression 1. In the example of the channel Cn in FIG. 9, the correction coefficient A = 1.6.
It becomes 5.

The other channels are obtained in the same manner.

Then, for the maximum and minimum basic current values, steps S10 to S10 in FIG.
If the processing of step S18 has been completed, the correction coefficient calculation processing (FIG. 4: step S1) ends, and the process proceeds to step S2 of FIG. The process is repeated (FIG. 5: step S19).

Next, in step S2 (FIG. 4), a test photosensitive film F of the same kind as the entire photosensitive film F which is assumed to be actually used in the image exposure apparatus 1 as a product.
, The above-described correction coefficient calculation process is repeatedly performed, whereby the correction coefficient A for the maximum and minimum basic current values for each of the test photosensitive films F is obtained for each of the channels C1 to C120, They are stored in any storage means. Then, when the process is completed, the process proceeds to the next step S3.

Next, in step S3 (FIG. 4), the image exposure apparatus 1 as a product is used instead of the test image exposure apparatus 2.
To perform the optimum current value setting processing. Hereinafter, the optimum current value setting process will be described with reference to FIG.

First, an operator attaches a target one of the predetermined test photosensitive films F to the rotary drum 20 of the image exposure apparatus 1 (FIG. 6: step S31).

Next, in the image exposure apparatus 1, thinning exposure is performed using the maximum or minimum initial current value (FIG. 6:
Step S32). Here, the maximum and minimum initial current values are predetermined current values substantially equal to the maximum and minimum basic current values in the above-described correction coefficient setting process, and are values common to each channel and each image exposure apparatus 1. Is used. The thinning exposure performed by the image exposure apparatus 1 is exactly the same as that performed by the test image exposure apparatus 2 in the correction coefficient setting process described above. Therefore,
In this optimum current value setting processing, thinning exposure is performed on different photosensitive films F according to the maximum and minimum initial current values, respectively. The processing in steps S33 to S36 is also the same as the processing in steps S13 to S1 in the correction coefficient setting processing in FIG.
Exactly the same as 6.

Next, the operator develops the test photosensitive film F subjected to the thinning exposure (FIG. 6: step S3).
3).

Next, the operator reads the image on the test photosensitive film F subjected to the thinning-out exposure by the line width measuring device (FIG. 6: step S34).

Next, the operator calculates the transmittance distribution of each scanning line using the line width measuring device (FIG. 6: step S3).
5).

Next, the operator measures the scanning line width of each channel by using the line width measuring device based on the obtained transmittance distribution (FIG. 6: step S36).

Next, the operator obtains a correction amount of the current value for each channel based on the correction coefficient corresponding to the maximum or minimum initial current value, the target scanning line width, and the measured scanning line width. The value is corrected and the maximum or minimum optimal current value is stored for each channel by an arbitrary storage means (FIG. 6: step S37).

The equation for calculating the amount of correction of the current value is given by the following equation.

Correction amount = A × corrected scanning line width / target scanning line width Expression 2 Here, the corrected scanning line width is obtained as a difference between the measured scanning line width and the target scanning line width. For example, any channel C
n, the initial current value is 2.5 mA, the target scanning line width is 5.0 μm, the measurement scanning line width is 4.0 μm, and the correction coefficient A is 1.65. 1.0 μm, and the correction amount of the current value is 0.33 mA.

Then, by adding the correction amount of the current value obtained in this way to the initial current value, an optimum current value obtained by correcting them is obtained. In the above example, the initial current value is 2.5 m
In A, since the correction amount of the current value is 0.33 mA, the optimum current value in the channel Cn is 2.83 mA.

In step S37, such a calculation is
An operator performs the process for each of the channels C1 to C120, and stores the maximum or minimum optimum current value of each of the channels C1 to C120 obtained by the operation by an arbitrary storage unit.

In the above, steps S31 to S31 of FIG.
If the processing in step S37 has not been completed, the processing in steps S31 to S37 is repeated for the other optimum current value, and the processing is performed for both the maximum and minimum optimum current values. Proceed to.

FIG. 10 is a conceptual diagram showing how the maximum and minimum optimum current values are set for any of the channels. As described above, the maximum and minimum optimum current values are obtained by adding the correction amounts of the current values to the maximum and minimum initial current values of each channel, and thereby, the target image exposure apparatus The scanning line width exposed by 1 approaches the target scanning line width as shown.

Next, the operator obtains the optimum current value for the desired resolution for each channel by interpolating the maximum and minimum optimum current values based on the scanning line width corresponding to the resolution. It is stored (FIG. 6: step S39).

As shown in FIG. 1, the image exposure apparatus 1 which is the object of this embodiment can change the magnification. Therefore, the above-described optimum current values must be obtained for each resolution and set in each image exposure apparatus 1. However, since the maximum and minimum optimum current values obtained above correspond to only two types of resolutions, no optimum current values are obtained for other resolutions.

Therefore, in this embodiment, the obtained maximum and minimum optimum current values are linearly interpolated, and for other resolutions, a current value such that a line width corresponding thereto is obtained for each channel. It is calculated for FIG. 11 is a diagram showing how the optimum current value is calculated for each of the resolutions of arbitrary channels Cn to Cn + 6 of one subgroup.
As shown, the method determines the point determined by the maximum optimal current value and the resulting scan line width (corresponding to the target scan line width in FIG. 10), the minimum optimal current value and the resulting scan line width. A straight line connects a point determined by the line width (corresponding to the target scanning line width in FIG. 10), and the current value at the scanning line width corresponding to the resolution required on the straight line is determined by the optimum current value at that resolution Is what you do.
In addition, such an optimal current value is set for each of the channels C1 to C1.
20 for all resizable resolutions,
The target image exposure apparatus 1 is set.

Next, in step S4 (FIG. 4), it is determined whether or not the processing for setting the optimum current value for all the predetermined photosensitive films F for testing has been completed, and the processing in step S3 is repeated until the processing is completed. This corresponds to steps S1-S in FIG.
3, the optimum current value was calculated for the specific type of the photosensitive film F for testing. This is because the image exposure apparatus 1 is an apparatus capable of performing image exposure on various photosensitive films F as described above. In the above-described correction coefficient calculation process, the optimum current value for each resolution is set for each of the predetermined various types of test photosensitive films F for which the correction coefficient A has been obtained.

Then, the predetermined photosensitive film F for various tests
If the optimum current value setting processing is completed for step S5
Proceed to.

Further, in step S5 (FIG. 4)
It is determined whether the setting of the entire image exposure apparatus 1 has been completed,
The processes in steps S3 and S4 are repeated until the process is completed. This is to set the above-described optimum current value for all of the image exposure apparatuses 1 (usually, a plurality) as products.

When the above setting is completed for all the image exposure apparatuses 1, the light intensity adjustment processing is completed.

As described above, according to the embodiment of the present invention, each of the channels C 1 to C
The test photosensitive film F is exposed by the first group G1 and the second group G2, which are non-adjacent groups, of the light beams by the light source 120, and the scanning line width of the scanning lines by the light beams of the respective channels C1 to C120. In order to adjust the intensity of each light beam by obtaining and setting the optimal current value of each of the channels C1 to C120 based on the above, the influence of the sub-exposure of each of the channels C1 to C120 is corrected, and the image exposure apparatus 1 It is possible to suppress unevenness in image exposure and perform high-quality image exposure.

In particular, since the exposure to the test photosensitive film F in step S2 in the light emission intensity adjustment processing shown in FIG. 4 is performed in each subgroup in the order of exposure at the time of actual image exposure, the photosensitive film F In this case, it is possible to adjust the light emission intensity by correcting the influence of the difference in sensitivity due to the order of the main exposure and the sub-exposure, so that the image exposure apparatus 1 further suppresses the unevenness of the actual image exposure and achieves higher quality image exposure. You can do it.

Further, since the light emission intensity adjustment processing is performed on various photosensitive films F, the light emission intensity can be adjusted according to the characteristics of the photosensitive film (photosensitive material).

Furthermore, since the first group G1 and the second group G2 are pairs of alternate light beams divided into odd and even channel numbers, the effects of weak sub-exposure can be corrected. In addition, the image exposure device 1 can further suppress unevenness in image exposure and perform high-quality image exposure.

<3. Modification> Although the image exposure apparatus according to this embodiment scans sequentially in the sub-scanning direction using a multi-beam, the present invention is not limited to this, and is also applicable to an image exposure apparatus that performs interlace exposure. be able to. Hereinafter, the thinning exposure at that time will be described.

FIG. 12 is a diagram for explaining the order of exposure by each of the channels C1 to C120 in thinning exposure by interlace. The meaning of each symbol is
7 are the same as FIG. 7 except for the numbers shown above the light beam by C120.

As shown in FIGS. 12A and 12B, in the final image by interlace exposure (not thinning exposure) in actual image exposure, scanning is performed from channel C120 to channel C1 in the sub-scanning direction. Lines are arranged in descending order of channel number. The order in which they are exposed is determined by the respective channels C1 to C1 in FIG.
20 in the order of the numbers shown above. Here, the same numbers indicate that the light emission is performed at the same timing. That is, in the interlaced exposure using 120 channels, the scanning line SU from the scanning line by the channel C120 to the scanning line by the channel C1 in the descending order of the channel number is set as one scanning unit SU, and the order of the sub-scanning direction (the positive side in the sub-scanning direction) (The later in time), and such a scanning unit SU is repeated in the sub-scanning direction.

In the thinning exposure, the scanning lines are formed in such a positional relationship and the order. In this case, only the light beams at the hatched positions in FIG. 12 form the scanning lines. Is not irradiated at that time. That is, FIG. 12A means that only each channel of the first group G1 emits light, and FIG. 12B means that only each channel of the second group G2 emits light.

Then, the optimum current value for each resolution may be set for each image exposure apparatus 1 by the thinning exposure method in the same manner as in the above embodiment. That is, the thinning exposure as described above is performed on the two types of test current values by the test image exposure device 2, and the correction coefficient A of each channel is obtained based on the obtained images.
Furthermore, the thinning exposure is similarly performed by the image exposure apparatus 1 as a product, and the maximum, minimum, and desired optimum current values may be obtained and set.

By performing such thinning exposure, the same effect as that of the embodiment can be obtained for an image exposure apparatus that performs interlace exposure.

Although the image exposure apparatus 1 in this embodiment uses the rotary drum 20, the present invention is not limited to this, and may use other scanning methods such as a flat type scanner. Alternatively, the photosensitive material for image exposure may be a material other than the photosensitive film F such as a printing plate.

In this embodiment, the thinning exposure is performed on each of the plurality of test photosensitive films F in one light emission intensity adjustment process. However, the present invention is not limited to this. A plurality of portions in the film F may be exposed.

Further, in this embodiment, the thinning interval at the time of thinning exposure, that is, the exposure is performed with every other light beam, but the present invention is not limited to this.
It is also possible to thin out the data at longer intervals, such as dividing into three subgroups every other time.

In this embodiment, the maximum and minimum initial current values supplied to the respective channels during the thinning-out exposure in the image exposure apparatus 1 as a product are the same among the image exposure apparatuses 1. The present invention is not limited to this, and the maximum and minimum optimum current values obtained in the image exposure apparatus 1 as the first product are set as the maximum and minimum initial current values in the second and subsequent image exposure apparatuses 1. May be used.

In this embodiment, in the optimum current value setting process, the optimum current values obtained for the predetermined maximum and minimum initial current values are stored in the image exposure apparatus 1 as they are. The present invention is not limited to this.
The thinning exposure is again performed using each optimum current value obtained by performing the optimum current value setting process as an initial current value, and a process of obtaining each optimum current value by obtaining a correction amount of the current value by Expression 2 is repeated. Thus, a more appropriate optimum current value may be obtained.

In this embodiment, the first group G
Although the target scanning line width in the first group G2 and the target scanning line width in the second group G2 are set to a common value, the present invention is not limited to this. Alternatively, a different target scanning line width may be set, such as setting the target scanning line width of the second group G2 in which exposure is performed smaller.

In this embodiment, each channel C
Although a desired optimal current value is obtained by linear interpolation using the maximum and minimum optimal current values of 1 to C120,
The present invention is not limited to this. In addition to the linear interpolation, an optimum current value and an optimum correction coefficient A for three or more resolutions are obtained.
Each is connected by a straight line to determine the optimum current value for the desired resolution based on it, or to be obtained by other interpolation methods such as using polynomial interpolation, and further obtained by extrapolation etc. The resolution may be determined for a resolution larger or smaller than the resolution.

Further, in this embodiment, the total number of channels is 120 and an even number is provided. However, the present invention is not limited to this, and other numbers such as an odd number of channels may be used.

[0095]

As described above, according to the first to fourth aspects of the present invention, among a plurality of light beams, light beams which are not adjacent to each other are irradiated to each subgroup which is a set of the light beams. Expose the material, measure its exposure,
In order to adjust the respective intensities of the plurality of light beams based on the measured exposure state, the influence of the mutual sub-exposure by the plurality of light beams is corrected, and the image exposure apparatus suppresses the unevenness of the image exposure, and provides a high quality image. Image exposure can be performed.

In particular, according to the second aspect of the present invention, since the exposure step is to expose the photosensitive material in the order of exposure during actual image exposure in a plurality of subgroups, the actual exposure in the photosensitive material Since exposure can be performed in which the influence of the difference in sensitivity depending on the order of the sub-exposure can be corrected, the image exposure apparatus can further suppress unevenness in image exposure and perform higher-quality image exposure.

Furthermore, according to the third aspect of the present invention, since the subgroup is a set of every other light beam among the plurality of light beams, the influence of the sub exposure can be corrected, and the image exposure can be performed. The apparatus can further suppress unevenness in image exposure and perform high-quality image exposure.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an image exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic structure of an LED array in FIG. 1;

FIG. 3 is a diagram showing a schematic configuration of a line width measuring device according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating a procedure of light emission intensity adjustment processing.

FIG. 5 is a flowchart illustrating a procedure of a correction coefficient calculation process.

FIG. 6 is a flowchart illustrating a procedure of an optimum current value setting process.

FIG. 7 is a diagram for explaining an exposure order by each channel of thinning exposure.

FIG. 8 is a diagram showing an image read by a line width measuring device and a transmittance distribution.

FIG. 9 is a diagram showing a scanning line width exposed by a current value slightly different from the minimum basic current value.

FIG. 10 is a conceptual diagram showing how the maximum and minimum optimal current values are set.

FIG. 11 is a diagram showing a state of calculating an optimum current value at each resolution of each channel.

FIG. 12 is a diagram for explaining an exposure order by each channel of thinning exposure by interlace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image exposure apparatus 2 Test image exposure apparatus 3 Line width measuring apparatus 30 Multi-beam head 31 LED array 45 Two-dimensional CCD camera 60 Control part 61 Touch panel 65 Mouse 75 Keyboard 95 Computer C1-C120 Channel G1, G2 1st group, 1st 2 groups (subgroups) F Photosensitive film, test photosensitive film (photosensitive material)

Claims (4)

[Claims] 1. An image exposure apparatus for scanning and exposing a photosensitive material with a plurality of light beams, comprising: a light intensity adjusting method for adjusting the intensities of the plurality of light beams; As one subgroup, a classification step of classifying the plurality of light beams into a plurality of subgroups, an exposing step of exposing the photosensitive material by irradiating the plurality of light beams for each subgroup, A light intensity adjusting method, comprising: a measuring step of measuring an exposure state of a photosensitive material; and an adjusting step of adjusting respective intensities of the plurality of light beams based on the measured exposure state. 2. The light intensity adjustment method according to claim 1, wherein the exposing step comprises:
A light intensity adjusting method, which comprises exposing the photosensitive material in the order of exposure in actual image exposure. 3. The light intensity adjusting method according to claim 2, wherein the plurality of subgroups are sets of every other light beam among the plurality of light beams. Strength adjustment method. 4. The light intensity adjustment method according to claim 3, wherein the measurement of the exposure state is a measurement of a line width of a plurality of scanning lines by each light beam of the plurality of subgroups. Adjusting the light emission intensity of each light beam such that the line width of the plurality of scanning lines is equal to a common target line width in the plurality of subgroups. Method.