JPS62178943A - Exposure controller - Google Patents

Abstract

PURPOSE:To control directly a light source in order to adjust a light quantity, and also, to adjust correctly the hue, by providing a program for adjusting the light quantity by adjusting the voltage of the light source, and also, adjusting the hue in accordance with the voltage adjustment. CONSTITUTION:When the copy start switch of a console panel is turned on, the arithmetic operation of a filter and its insertion quantity, and the arithmetic operation of a voltage value of a light source for determining a light quantity are executed during the timer time, and when its timer time is elapsed, a first filter plate 61 is controlled, based on the arithmetic operation, and when this control is completed, a second filter plate 62 is controlled, based on the same arithmetic operation, and when its control is completed, the voltage of the light source for determining the light quantity is controlled, based on the arithmetic operation. In this way, in case of adjusting the density, namely, the light quantity by varying the power supply voltage of the light source, a color balance conforming to a photosensitive material can be held by adjusting the input of the filter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exposure control device for a color copying machine.

[Background of the invention]

A color copy image is created by projecting image light carrying an image of a color original onto a color photosensitive material, exposing the color photosensitive material, and then processing the color photosensitive material in a processing section such as development and fixing. Obtainable.

Such a color copying machine is required to be able to correct the color of the image light according to the spectral sensitivity characteristics of each color of the color photosensitive material, and to be able to adjust the density.

As a hue control for this purpose, a method is adopted in which three color filters are inserted in the middle of the optical path of the image light and the amount (ratio) of their insertion is controlled.

As such three-color filters, filters that block specific hue wavelengths are used, and specifically, a yellow filter that blocks blue light, a magenta filter that blocks green light, and a cyan filter that blocks red light are used. used.

On the other hand, there are two methods for adjusting the density (light amount): inserting an aperture in the optical path and directly controlling the light source, but the latter is preferable since it does not involve a mechanism.

However, when directly controlling a light source, it is necessary to change its power supply voltage, but when changing the power supply voltage of halogen lamps, etc., the color temperature characteristics change.
There is a possibility that the hue control described above may be disrupted.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure control device that can properly adjust hue while directly controlling a light source to a -113J1 level.

[Structure of the invention]

For this purpose, the exposure control device of the present invention is configured to adjust the amount of light by adjusting the voltage of the light source and to include a program that adjusts the hue in accordance with the voltage adjustment.

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a diagram showing an exposure part in a color copying apparatus. A color original (not shown) placed on a platen glass 1 is exposed and scanned by a light source 2 moving at a constant speed in the direction of arrow a. The image light obtained by reflection passes through a mirror 3 that is integrated with the light source 2, an integrated mirror 4.5 that moves in the same direction as the light source 2 at a speed that is twice the moving speed of the light source 2, and a lens and Lyrutor. After passing through the provided lens system 6, the light enters the exposure window 7.

In this exposure window 7, the color photosensitive material moves in the direction indicated by the arrow in synchronization with the movement of the light source 2, and the photosensitive material is sequentially exposed during the movement.

Therefore, if this color photosensitive material is then sent to a processing section for color development, fixing, bleaching, drying, etc., a color copy image corresponding to a color original can be obtained.

FIG. 2 shows details of the above-mentioned lens system 6. Along the optical path C, a first filter plate 61, a second filter plate 62
, and a lens 64 are arranged.

As shown in FIG. 3, the first filter plate 61 has a yellow (hereinafter referred to as Y) filter 61Y and a magenta (hereinafter referred to as M) filter 61M at both ends, and a transparent portion 61T in the center. The second filter plate 62 has a Y filter 62Y and a cyan (hereinafter referred to as C) filter 62C at both ends, and a transparent filter 62C in the center.
It is T.

Both filters 61 and 62 are the M filter 6
The home position is the position where the center of 1M and the center of the C filter 62C coincide with the optical axis C, and each of them can be moved in the opposite directions of arrows d and e (left and right directions across the optical path C) by stepping motors 65 and 66. It becomes.

Therefore, by appropriately controlling both stepping motors 65 and 66, the optical path C has: (1) No filter...no hue correction.

■Insertion amount of one filter from Y, M, C: 0 to 10
0%...1 type of hue and saturation correction.

■Combination of two of the three types of filters Y, M, and C, that is, a combination with an insertion amount of O to 100% for each of Y and M, and a combination of an insertion amount of O to 100% of each of M and C. ,
Filters can be inserted in combinations of insertion amounts of 0 to 100% for each of C and Y.

In this color copying machine, when the copy start switch on the operation console is turned on, the calculation of the filter and its insertion amount and the voltage value of the light source 2, which determines the amount of light, are performed during timer time T0, as shown in FIG. and its timer time T.

When , the first filter plate 61 is controlled based on the above calculation, and when this control is completed, the second filter plate 62 is controlled based on the same calculation as above. The voltage is controlled based on the above calculation. After this, the light source 2 starts exposure scanning.

Next, a method for creating a color filter control program will be described. FIG. 5 shows the light transmission characteristics of each of the Y, M, and C filters. As is clear from this figure, the intensity (light amount) of blue (B) is inversely proportional to the amount of Y filter inserted, the intensity of green (G) is inversely proportional to the amount of M filter inserted, and red (R ) is inversely proportional to the amount of insertion of the C filter.

Color C obtained by inserting each filter plate 61 and 62 into the optical path
L, is CLo = aoY +boM +coC・(i)a,:
F value of Y filter bo: F value of M filter Co20 It is given by F value of filter. The F value indicates the amount of insertion. Therefore, each F
The value is determined in advance according to the spectral sensitivity characteristics of each color of the color photosensitive material used, and the hue at this time is used as the preset value.

Note that, as described above, since two of the three types of filters are used, the remaining one type needs to be replaced with the other two types. Therefore, the filter with the smallest F value (the filter with the smallest amount of insertion) is replaced with the other two types. For example, a, <
b. If <00, then (11 formula % formula %) Therefore, the hue is adjusted using the M filter and the C filter. This becomes the actual preset value of the filter corresponding to the color photosensitive material used.

As a result of the above, color correction is performed using the filter in accordance with the color development characteristics of each color of the color photosensitive material.

The above is a case where the voltage of the light source is constant. Next, a case will be described in which the voltage of this light source is changed to change the amount of light, thereby adjusting the depth. In this case, if the voltage changes, the color temperature of the light source 2 will also change, so color correction is simultaneously performed in accordance with this color temperature change.

This color temperature change will be explained below. In Fig. 6, (al) indicates the color temperature characteristics of the halogen lamp used as light source 2. The broken line is the characteristic when the applied voltage is 80 V, and the solid line is the characteristic when the applied voltage is 60 V. Compare these two characteristics. As a result, it can be seen that the intensity is relatively stronger on the long wavelength side when the voltage is lower than on the other wavelength ranges.In other words, the lower the voltage, the more reddish the hue becomes.

Therefore, the intensity that is neutral to the photosensitive material used (this intensity is equivalent to the light transmittance for the filter) is set to N as shown in FIG. 6(b), TO). At this time, when the power supply voltage of the halogen lamp is 60V, the characteristics shown in (b) are that the light in the blue B region is neutral, and the light in the green G region is slightly strong 2G.
, it is assumed that the light in the red R region has a fairly strong 3B characteristic.

At this time, without inserting a Y filter that blocks blue B (OY), insert a 2M M filter that blocks green G,
If 30 C filters that block red are inserted, the parts stronger than neutral N will be canceled out, and the intensities of the three primary colors will be aligned with neutral N. In other words, the color balance for the photosensitive material is maintained.

Here, in order to reduce the concentration, for example, if the power supply voltage of the halogen lamp 1 is increased from 60v to 80v, the BGR
For example, as shown in Figure 6 (C), the light in the blue B region is IB, and the light in the green G region is 4G.
, the light in the red R region becomes stronger to 6R.

Therefore, in this case, the Y filter that blocks blue B should be obtained using the neutral N' (new density 5 ig
), in order to balance the taste and color, of course, do not insert the Y filter that blocks blue, but insert only 3M M filter that blocks green G, and 50 C filter that blocks red. The parts stronger than the neutral N' corresponding to the density are canceled out, and the intensities of the three primary colors become aligned with the neutral N'.

As described above, when the density, that is, the amount of light is adjusted by changing the power supply voltage of the light source, the color balance suitable for the photosensitive material can be maintained by simultaneously adjusting the amount of filter input.

Since the color temperature characteristics of the light source are known, the amount of correction by the filter corresponding to the intensity changes of BC and R for this color temperature characteristic is written in advance as a table in memory (ROM, etc.), and the hue including density adjustment is calculated in advance. If the adjustment is controlled by PLC, the filter will be controlled at the same time when the power supply voltage is adjusted to change the amount of light, and the color balance will be maintained at all times.

〔Effect of the invention〕

As described above, according to the present invention, if the voltage of the light source is adjusted to adjust the light amount, the color balance can also be adjusted at the same time, and it becomes possible to maintain an appropriate color balance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the exposure scanning portion for a document of a color copying apparatus according to an embodiment of the present invention, FIG. 2 is a detailed diagram of the lens system portion in FIG. 1, and FIG. 3 is an explanatory diagram of driving the filter plate. , Fig. 4 is a timing chart of the filter plate and light amount adjustment operation, Fig. 5 is a light transmission characteristic diagram of the third type filter YMC, Fig. 6 (a) is a diagram showing the color temperature characteristic of the light source, (BL and (C) are explanatory diagrams of color balance correction. Agent: Patent Attorney Tsuneaki Nagao Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) An exposure control device that adjusts the hue by moving a color filter in and out of the optical path, which is equipped with a program that adjusts the amount of light by adjusting the voltage of the light source and adjusts the hue according to the voltage adjustment. An exposure control device characterized by: