JP2884369B2 - Photo printing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in exposure condition setting means for printing from a negative screen to zoom magnification in a photographic printing apparatus having a zoom lens.

[Conventional technology]

The prior art will be described with reference to a side view showing the configuration of a photographic printing apparatus shown in FIG. The negative screen 1 at a fixed position on the negative mask 1a is irradiated with diffused light of a predetermined luminance from the back surface by a light source 9 through a heat insulating filter 8, a YMC cut filter 7, and a mirror tunnel 15. The negative screen 1 is projected by the zoom lens 3, and the projected image is formed on the emulsion surface of the photographic paper 6 via the reflection mirror 5. In order to create a projection image of a required magnification from the negative screen 1, the lens element of the zoom lens 3 is moved in the optical axis direction to change the focal length. In the exposure of the photographic paper 6, an appropriate image surface exposure amount is determined by a combination of an optimal numerical value of the aperture of the diaphragm 2 in the zoom lens and the opening time of the shutter 4 at a fixed position on the optical path. . The amount of exposure when zooming to a different size from a predetermined standard print size or by changing the negative mask of the negative screen 1 to perform trimming and changing to an arbitrary size depends on the opening time of the shutter 4. The aperture value is changed in proportion to the magnification, and the aperture value is manually adjusted to select the aperture value so that the appropriate exposure is the same as the standard size image plane exposure amount. Then, the aperture value is determined while measuring the image plane illuminance near the image forming plane or making a determination by trial printing or the like, thereby determining the exposure condition.

[Problems to be solved by the invention]

In general, in order to produce a projection image having many different magnifications from a negative screen 1 of a photographic printing apparatus and a trimmed image of the negative screen 1, the focal length of the built-in zoom lens 3 is changed to correspond to this. Therefore, when the focal length of the lens is changed, since the aperture diameter D of the lens is constant from the relationship of F No. = f / D, the brightness F No. (hereinafter sometimes simply referred to as F) naturally changes. . This means that the image plane exposure of projection images of different magnifications formed on the negative screen 1 having a constant luminance through the zoom lens 3 also changes. For example, assuming that the shutter opening time is constant, when the projection image of the print size of the service size E plate is exposed on the photographic paper 6 from the negative screen 1 of the 35 mm plate using the zoom lens 3, the aperture value is set to the standard value. When an optimum image plane exposure amount is used, when making a six-cut plate or a four-cut plate larger than that, the focal length of the zoom lens 3 must be changed. At this time inevitably F _NO of the zoom lens 3 is changed it is necessary to change the aperture value to the same exposure amount and the image plane exposure quantity of the aforementioned E version print size. Conversely, in the case where the negative screen 1 has an image plane exposure amount that is changed from a half-size half-size plate of 35 mm plate to an E-plate print size, the aperture value is changed in the same manner as described above, and the standard image surface exposure is performed. It is necessary to match the amount of light. Conventionally, when converting to these various magnifications, the aperture value is manually changed, or the shutter opening time is changed to perform trial printing, and it is determined whether or not the exposure value coincides with the standard optimal image surface exposure amount. This is an extremely inefficient operation, especially in high-speed photographic printers that process more than 30 prints per minute, because each time the magnification is changed, the device is stopped and a long time is set up to select the amount of exposure. Had become.

Further, since the selection of the exposure amount is a human operation based on experience, there is a drawback that the image quality exposure amount often varies every time the magnification is changed, thereby deteriorating the print quality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photographic printing apparatus capable of solving this problem and selecting an accurate image-surface exposure amount in a short time at any print size.

[Means for solving the problem]

This object is achieved by one of the following means (a), (b) and (c).

(A) Equipped with a zoom lens having an aperture adjustment function, an illuminance detection sensor provided on the exposure axis, and an optimal aperture value (the aperture value means the size of the aperture diameter) while detecting the illuminance on the projection surface of the negative screen. Is determined), and for each zoom magnification position,
A photographic printing apparatus characterized by storing respective optimum aperture values.

(B) In the photographic printing apparatus according to the above (a), means for setting the stored aperture value for a specified required print size, and automatic exposure amount at the print size from an optimum F No. Photographic printing apparatus comprising:

(C) The photographic printing apparatus according to the above (a) or (b), wherein the negative screen is provided with a variable mechanism on a negative mask so that a trimming amount of the negative screen can be changed.

〔Example〕

An embodiment of the present invention will be described with reference to a perspective view of a photographic printing apparatus shown in FIG. 1 and a relation diagram regarding the illuminance of a lens L, an object S and an image S 'shown in FIG. However, the present invention is not limited to this embodiment. Those having the same functions as the conventional ones are represented by the same symbols. The negative screen 1 at a fixed position of the mask 1a provided in the photoprinting apparatus has a heat insulating filter 8 and a YMC by a light source 9 having a predetermined brightness.
Uniform diffused light is emitted from the back surface through the cut filter 7 and the mirror tunnel 15.

In the negative image 1, a zoom lens 3 is attached to a lens mount 3 a at a fixed position on a predetermined optical path so as to face the negative screen 1. The projection image of the negative screen 1 created by the zoom lens 3 is once bent at a right angle on a surface of a reflection mirror 5 fixedly mounted on a device table (not shown) on the same optical path to be at a predetermined image forming position. An image is formed on a certain photographic paper 6 surface. Since the present photo printing apparatus is provided with the zoom lens 3, it can be enlarged to various print sizes from the same negative screen, and can be enlarged to any print size from different negative screens. When the image magnification is changed by the zoom lens 3, the lens element in the zoom lens 3 is moved to change the focal length so that a print with a required image magnification can be obtained. In the zooming operation of the zoom lens 3, the focal length is calculated in advance for each print size to be enlarged from the negative screen, stored in the CPU, and the zoom motor 14 disposed in the lens barrel 3b is driven by the control of the CPU. Then, the lens element in the zoom lens 3 is moved in the optical axis direction.

When the zoom lens 3 reaches the focal length position of the required magnification, the zoom motor 14 is stopped by the control of the CPU receiving the detection information of the zoom position detection sensor 13 to set the new focal length f and the zoom magnification position. Is done. If the zoom lens 3 whose focal length f has been changed in this way has a constant lens aperture D, the brightness F No. will inevitably change from the relational expression of F No. = f / D. The image plane illuminance on the paper 6 also changes. In general, the following relational expression is established for the image plane illuminance from the relational diagram of the lens, the object and the image shown in FIG. That is, a small area on the optical axis above a perfectly diffusing planar object S having a luminance of Bcd / m ² on the subject surface is denoted by ds, and a small area on the image S ′ of the object S by the lens L is denoted by ds ′. I do. Also, the light flux Φ entering the lens L from ds is given by a solid angle w ₀ extending over the aperture D of the entrance pupil A. Becomes Where u is the distance from the entrance pupil A plane to the object S,
D is the entrance pupil diameter. 'If = a m ² ds ... ⁽²⁾ the transmittance of the lens L and t, the light flux of tΦ is ds' if the magnification of the lens L and m ds illuminance E ₀ of the image plane from condensing on the Becomes f is the focal length of the lens, and x is the distance from the front focal point of the lens to the object S. From the lens general formula The equation (4) is an expression that gives the image illuminance E ₀ on the optical axis including image magnification. Also, the image plane exposure amount E is calculated from the F No. and the magnification m. There is a relational expression. Then the image plane exposure at F ₁ When E ₁ In certain magnification m _1, the image plane exposure quantity E ₂ to be the F ₁ at a magnification of m ₂ is introduced from (5) Is obtained. From these facts, the F No. changes according to the change in the focal length of the zoom lens 3. For example, each time a different magnification is set from the standard value, the shutter opening time and the aperture value are changed so that the photographic paper 6 surface is always changed. It is necessary to provide a prescribed image plane exposure. Therefore, the present invention differs from the conventional method of manually changing the aperture value and the shutter opening time in that the illuminance detection sensor 10 is located near the optical axis of the image forming plane.
Is arranged. The illuminance information received by the illuminance detection sensor 10 is sent to the CPU at the same time when the focal length of the zoom lens 3 is changed.

FIG. 3 shows the relationship between the magnification m and the F No. Here, F No. is used to improve print quality.
o to increase the exposure time or to shorten the exposure time to lower the F No. in order to increase the productivity, but to improve the print quality and the productivity. The optimum F No. F (m) for each magnification m is a curve shown by a dotted line in FIG.

Wherein the CPU to exposure E ₁ of the image plane of the diaphragm 2 standard magnification m ₁ while operating the, optimal F No.F at any magnification m ₂
expressed in m ₂ of the function F (m _2), the exposure amount E ₂ at that time It is represented by

And (7) going to store the closest Nuisance aperture detection sensor 11 CPU the aperture and the magnification m ₂ with the optimal F No.F (m ₂₎ based on the output of the equation. And disposed in the lens barrel 3b by this way the control of any of the CPU of the image plane exposure amount is changed in the magnification m _2, and aperture ratio such that a fixed relationship is combined and stored The diaphragm motor 12 is driven to move the diaphragm 2. When a predetermined aperture value is reached, the detected position is fed back to the CPU by the aperture position detection sensor 11 disposed on the lens barrel 3b, and the drive of the aperture motor 12 is stopped again under the control of the CPU, thereby stopping the predetermined aperture. Value.

The shutter opening time T ₂ at a magnification of m ₂ is the magnification m ₁
The following equation from the shutter opening time T ₁ of the (8), (9), (10)
Is obtained as follows.

Here, K is a proportional constant between the image plane exposure amount and the print density.

If the shutter opening time T _{1 at the} magnification m ₁ has been adjusted in advance, the aperture value associated with F _No. F (m ₁ ) and F (m ₂ ) is stored in advance, so the shutter opening time T for the magnification m _{2 2} is obtained. Therefore, even if the print size is changed from the negative screen to any print size other than the standard print, the same appropriate image surface exposure amount and shutter opening time as those set in the standard print are always given to the photographic paper 6. The illuminance detection sensor 10 may be provided at a predetermined position on the optical axis, not necessarily near the image plane. Also, this image plane exposure amount can be changed in any way by a combination of both the aperture value of the lens and the shutter opening time,
The same exposure amount can be obtained by rearrangement. From this, it is possible to change the shutter opening time while keeping the aperture value constant so as to correspond to the change in the focal length of the zoom lens 3, and such an exposure means is naturally included in the embodiment of the present invention.

Further, the mask 1a is provided with a variable mechanism of a negative mask S having upper and lower movable frames 1b and 1c and left and right movable frames 1d and 1e as shown in FIGS. Standard magnification no matter how the height and trimming position are changed
It is obvious that the arbitrary magnification m ₂ and F _No. F (m ₂ ) with respect to m ₁ can be made to correspond to the optimum value from the viewpoint of quality and productivity while the exposure amount is constant.

〔The invention's effect〕

Since the photographic printing apparatus of the present invention is configured as described above, a predetermined appropriate image surface exposure amount is always automatically selected from the screen or a trimmed version of the screen at any print size. In addition, since the shutter opening time is automatically calculated, even at the time of zooming, a print image having a uniform color tone is produced, and the print quality is remarkably improved. In addition, since the time and effort for setting up the aperture value manually or performing trial printing each time during zooming as in the related art can be eliminated, the operation rate of the photographic printing apparatus can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of a photographic printing apparatus according to one embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the lens and the illuminance of an object and an image. FIG. 3 is a curve showing the relationship between magnification and aperture value. 4 (a) and 4 (b) are plan views of a negative mask having a trimming function. FIG. 5 is a side view showing the configuration of a conventional photographic printing apparatus. 1 Negative screen 1a Negative mask 1b, 1c Vertical movable frame 1d, 1e Left and right movable frame 2 Aperture 3 Zoom lens 3a Lens mount 3b Lens barrel 4 … Shutter 5… Reflection mirror 6… Print paper 7… YMC cut filter 8… Heat protection filter 9… Light source 10… Illuminance detection sensor 11… Aperture value detection sensor 12… Aperture motor 13 ... Zoom position detection sensor 14 ... Zoom motor, 15 ... Mirror tunnel

──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Hiroshi Ishii 1 Sakuracho, Hino-shi, Tokyo Konica Co., Ltd. Examiner, Kiyoshi Shigemasa (58) Field surveyed (Int. Cl. ⁶ , DB name) G03B 27 / 72 G03B 27/34 G03B 27/50

Claims (3)

(57) [Claims] An iris detection sensor is provided on an exposure axis to detect an illuminance on a projection surface of a negative screen and an optimum aperture value (the aperture value is a size of the aperture diameter). ) And stores the optimal aperture value for each zoom magnification position. 2. A photograph printing apparatus according to claim 1, wherein said stored aperture value is set for a designated required print size, and an exposure amount at said print size is automatically determined from an optimum F No. Photographic printing apparatus comprising: 3. The photographic printing apparatus according to claim 1, wherein the negative screen is provided with a variable mechanism on a negative mask so that a trimming amount of the negative screen can be changed.