JPH0673004B2 - Light control device for photo printing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light control device for a photographic printing apparatus, which is used in a photographic printing apparatus such as a color printer or a color photographic enlarger to adjust the color component of a light source.

[Conventional technology]

A light control device has been devised in which two filters are made to face each other and the area of the opening between them is changed exponentially with respect to the movement amount of the filters (Actual Publication No. 54-164557).

The integrated transmission density of the filter changes logarithmically with the amount of transmitted light. Therefore, the integrated transmission density of the filter is a linear function of the moving amount of the filter. Therefore, the filter can be moved quickly and the dimming accuracy can be improved.

[Problems to be solved by the invention]

However, since the end face shape of the filter on the opening side is an exponential function, it is not easy to cut it. Further, cutting accuracy is required.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a light control device for a photographic printing apparatus having a filter which is easy to manufacture.

[Means for solving problems]

In order to achieve the above object, the light control device for a photographic printing apparatus of the present invention is a dimming device corresponding to each of the three primary colors so that the boundary line with the transparent part is formed on a part of the transparent substrate by an exponential function curve or an arc. Each of the filters is coated with a light coloring material, and the filters are arranged so as to be able to move in and out of the exposure optical path from three directions forming an angle of about 120 degrees.

[Action]

In the filter of the present invention, the boundary with the transparent portion of the light control color material deposited is formed by an exponential curve or arc, and it is not necessary to cut the light source optical path side end of the filter along the exponential curve. Therefore, the filter can be easily manufactured.
Further, the cutting accuracy of the filter does not matter.

Further, this filter is coated with a dimming color material corresponding to each of the three primary colors, and these filters are arranged so as to be able to uniformly move in and out of the exposure optical path from three directions forming an angle of approximately 120 degrees. Therefore, dimming of each color becomes easy.

〔Example〕

First, a comparative example will be described in which a dimmer as a dimmer for a photographic printing apparatus uses opposing filters each having a boundary line with a transparent portion formed by an exponential function curve.

FIG. 1 shows the main configuration of the color printer.
Color film arranged between the lamp 10 and the lens 12
The image of 14 is formed on the roll photographic paper 16 and exposed.

The lamp 10 is provided inside the concave mirror 17,
The light is emitted upward. A dimming device 18 and a mixer 20 are provided in the exposure light path between the lamp 10 and the color film 14. The light control device 18 includes a cyan light control section 22, a magenta light control section 24, and a yellow light control section 26 which are arranged at regular intervals in the vertical direction. These cyan light control section 22, magenta light control section 24 and yellow light control section 26
Have the same structure except for the color of the filter.

FIG. 2 shows the configuration of the cyan light control section 22, in which rectangular cyan filters 28 and 30 are attached to the edges of the openings 36 and 38 provided in the bases 32 and 34, respectively. Base 32, 34
Legs 40, 42 and 44, 46 are cut and raised at one end of
A screw rod 48 is screwed into these. A right male thread 50 is engraved on the leg piece 40 side of the screw rod 48, and a left male thread 52 is engraved on the leg piece 46 side. Both ends of the screw rod 48 are pivotally supported by side plates 54 and 56. A guide bar 58 is horizontally mounted on the side plates 54 and 56 on the side opposite to the screw rod 48, and the base 34 is mounted on the guide bar 58. Spacers 59 that slide with the base 34 are provided at the corners of the base 32.
Is attached so that the cyan filter 30 and the base 32 do not come into contact with each other. At the end of the screw rod 48 protruding from the side plate 54, a pulse motor 62 is
Is installed.

Therefore, the pulse motor 62 is turned on and the screw rod 48
When is rotated clockwise, the bases 32 and 34 move in a direction away from each other. Further, when the screw rod 48 is rotated counterclockwise, the bases 32 and 34 move toward each other.

The cyan filter 28 has a light control section 64 in which a cyan color material is vapor-deposited on a transparent substrate and a transparent section 66 in which the cyan color material is not vapor-deposited. The boundary line between the light control section 64 and the transparent section 66 is an exponential curve, and if the xy orthogonal coordinate system is taken as shown in FIG. 2, this boundary line is expressed by the following equation.

y = ae ^−bx + c (1) where a, b, and c are constants.

The curve B is symmetrical to the curve A with respect to the X axis.

The cyan filter 30 has the same configuration as the cyan filter 28. The area of the transmission part 68 surrounded by the curves a, b, c, and d is exponential with respect to the movement amount of the bases 32 and 34, that is, the rotation amount of the pulse motor 62. Transmission part 68
Since the logarithm of the amount of light transmitted through is proportional to the cumulative transmission density of the filter, the cumulative transmission density of the filter is
Is a linear function of the rotation amount of. Therefore, the dimming accuracy can be improved, and the cyan filters 28 and 30 can be quickly moved to desired positions.

Next, the first embodiment of the present invention will be described in detail with reference to FIG.

In the first embodiment, the light control device 18 includes a cyan light control section 70, a magenta light control section 72, and a yellow light control section 74.
The cyan light control section 70, the magenta light control section 72, and the yellow light control section 74 are arranged at an angle of 120 degrees.

In the cyan light control unit 70, one end of a cyan filter 80C is fixed to the tip of an arm 78C. The base end of the arm 78C is attached to the pulse motor 84C via the speed reducer 82C, and the cyan filter 80C is rotationally driven in the direction of the arrow in FIG. The cyan filter 80C is similar to the cyan filter 28 of the comparative example described above, in the light control section 64 (hatched section).
And a transparent portion 66.

The magenta dimming unit 72 and the yellow dimming unit 74 also have the same configuration as the cyan dimming unit 70, and the same parts are designated by the same reference numerals and M and Y are assigned instead of C, respectively.
However, the light control units 64 of the cyan filter 80C, the magenta filter 80M, and the yellow filter 80Y have cyan, magenta, and yellow colors, respectively.

When the arms 78C, 78M, 78Y are rotated clockwise,
The area of the light source optical path portion 86 surrounded by the cyan filter 80C, the magenta filter 80M, and the yellow filter 80Y is reduced, and the amount of transmitted light of red, green, and blue is limited according to the rotational movement amount of each. This transmitted light quantity is the arm 78C, 78M,
It changes exponentially with respect to the rotation angle of 78Y. Therefore, as in the case of the comparative example, the integrated transmission densities of the filters for each of the three primary colors are linear functions of the rotation angles of the arms 78C, 78M, and 78Y.

As described above, in the first embodiment, unlike the comparative example, the cyan filter 80C, the magenta filter 80M, and the yellow filter are used.
It is enough to provide one 80Y each, arm 78C,
Since the 78M and 78Y need only be rotated, the configuration is simple. Moreover, Cyan Filter 80C, Magenta Filter 80
It is possible to reduce the attenuation of the amount of transmitted light due to the overlapping of the transparent portions 66 of the M and yellow filters 80Y.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, a U-shaped frame 9 is provided at the tip of the arm 88C.
0C is formed, and the edge of the cyan filter 92C is fixed to the frame 90C. The magenta light control section and the yellow light control section have the same configuration as the cyan light control section except for the color of the filter.

Since the second embodiment has the frame 90C, there is an advantage that a thin filter can be used.

In each of the above embodiments, the curve of the boundary between the light control section 64 and the transparent section 66 does not need to be exactly exponential, that is, the integrated transmission density of the filter is a substantially linear function of the movement amount of the filter. However, it may have an arc shape.

〔The invention's effect〕

In the light control device for a photo printing apparatus according to the present invention, a transparent substrate is provided with a filter coated with a light control color material so that the boundary with the transparent portion is formed by an exponential curve or an arc. Since it is not necessary to exponentially cut the end of the filter on the side of the light source path, it is easy to manufacture, and the filter uses one filter for each color coated with a dimming color material corresponding to each of the three primary colors. It has a simple structure, and since these filters are arranged so that they can enter and leave the exposure light path evenly from three directions forming an angle of approximately 120 degrees, the dimming of each color is facilitated, which is an excellent effect. Have.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a photographic printing apparatus used as a comparative example,
FIG. 2 is a perspective view of a cyan light control section, and FIG. 3 is a first view of the present invention.
FIG. 4 is a plan view of a light control device showing an embodiment, and FIG. 4 is a partial plan view of a light control device showing a second embodiment of the present invention. 18 …… dimming device, 22, 70 …… cyan dimming part, 24, 72 …… magenta dimming part, 26, 74 …… yellow dimming part, 28, 30 …… cyan filter, 60 …… reducer , 62 ... Pulse motor, 64 ... Dimming part, 66 ... Transparent part, 68 ... Transmissive part, 80C, 92C ... Cyan filter, 80M ... Magenta filter, 80Y ... Yellow filter, 82C, 82M, 82Y …… Reducer, 84C, 84M, 84Y …… Pulse motor.

Claims (2)

[Claims] 1. A transparent substrate is provided with one filter each having a dimming color material corresponding to each of the three primary colors so that a boundary with the transparent portion is formed by an exponential function curve or an arc. In addition, a light control device for a photographic printing apparatus, in which the filter is arranged so as to be able to move in and out of the exposure light path from three directions forming an angle of approximately 120 degrees. 2. The light control device for a photographic printing apparatus according to claim 1, wherein the boundary line is formed by two exponential function curves or arcs which are symmetrical with respect to an axis.