JPH0544656B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photographic printing apparatus having a function of automatically calibrating an output signal of a photodetector for measuring film transmission density.

[Prior Art] Calibration of the output signal of a photodetector for measuring film transmission density has generally been performed only before installation in a photographic printing apparatus.

[Problems to be Solved by the Invention] However, errors occur in the output signal of the photoreceiver due to fluctuations in ambient temperature, etc., resulting in a decrease in the measurement accuracy of film transmission density.

For this reason, technology that utilizes reflection from the shutter surface (for example, see Japanese Patent Publication No. 13309/1973),
By combining technology that allows photometry of dark current and transmitted images with a light receiver according to the opening and closing of the shutter (for example, see Utility Model Application No. 59-138848), even after the printing equipment has been installed, it is possible to Bration becomes possible.

However, with the above configuration, only a part of the image cannot be photometered, so LATD (accumulated transmission density) cannot be measured, and although it is suitable for character images such as microfilm, it is not suitable for landscape images.

Furthermore, if the shutter is not operated correctly, accurate photometry will not be possible and the calibration will be inaccurate.The present invention takes the above facts into consideration, and allows the LATD of an image to be photometered, making it possible to measure the LATD of the shutter. It is an object of the present invention to provide a photographic printing apparatus which is capable of calibrating a light receiver depending on the operation and is also capable of detecting malfunction of the shutter.

[Means for Solving the Problems] In order to solve the above problems, the photographic printing apparatus according to the present invention provides a reflective surface (including a mirror surface and a diffusely reflective surface) on the surface of the shutter on the film side. A light receiver for measuring film integrated transmission density is disposed outside the exposure path facing the reflective surface at the time, and a light shielding means blocks external light from entering the light receiver.
The received light amount correcting means corrects the output signal of the light receiver based on the signal value from the light receiver in the dark when the shutter is open.

Furthermore, if the difference between the amount of correction during this correction and the amount of light received when the shutter is closed is less than a preset value, a warning of shutter malfunction is issued.

The lens may be disposed on either the film side or the photographic paper side of the shutter.

[Operation] When the shutter is closed, the light source light that has passed through the film is reflected by the reflective surface of the shutter and enters a light receiver for measuring transmission density, and the film transmission density is measured. In accordance with this measured density, the shutter open time and the cut time of the light source light of the cut filter corresponding to each of the three primary colors are determined.

The output signal value ε of the light receiver in darkness when the shutter is open is read by the received light amount correcting means, and the output signal E of the light receiver when the shutter is closed is automatically corrected based on the previous value ε. Note that in the dark when the shutter is open, the exposure light source is turned off.

Further, in the present invention, it is possible to determine whether there is an abnormality in the opening/closing operation of the shutter based on the output signal from the light receiver.

The output signal (E>ε) when the shutter is closed is
If the shutter operates normally, the light transmitted through the film from the light source will naturally reach the light receiver, so that a difference exceeding a predetermined value will occur between the output signal ε and the output signal ε in the dark when the shutter is open.

However, if the shutter does not operate normally, for example if it does not open completely, a portion of the transmitted light will be reflected by the reflective surface and will be received by the light receiver.

Therefore, the output signal E when the shutter is closed is
The difference between the output signal ε and the dark output signal ε when the shutter is open becomes less than or equal to the predetermined value, and a malfunction of the shutter can be recognized and a warning can be issued.

[Embodiment] An embodiment of a photographic printing apparatus according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, an image on a color film 13 placed between a lens 10 and a light source 12 is formed onto photographic paper 14 and exposed. Disposed between the light source 12 and the color film 13 are cyan, magenta, and yellow color correction filters 20, 22, and 24 and cut filters 26, 28, and 30 corresponding to red, green, and blue, respectively. The cut filters 26, 28, 30 are each driven by a rotary solenoid group 32. A shutter 3 is located between the lens 10 and the photographic paper 14.
4 is provided and is driven by a rotary solenoid 36. The shutter 36 is opened against the biasing force of a return spring (not shown) by energizing the rotary solenoid 36.
By demagnetizing it, it is closed by the biasing force of the return spring. A reflecting surface 37 (a mirror surface or a diffusely reflecting surface) is provided on the lower surface of the shutter 34 (the surface on the film 13 side). On the outer periphery of the lens 10 toward the center of the opposite slope 37, three light receivers 38 corresponding to red, green, and blue color light are provided so as to be shielded from external light. This light receiver 38 has
Light reflected from the reflective surface 37 or light reflected from photocopy paper 16, 16A, which will be described later, is input, and an electrical signal corresponding to the amount of input light is output. There is. Shutter 3
4, a photographic paper loading section 40 is provided nearby.

This photographic paper loading section 40 is, as shown in FIG.
Rails 42 and 44, which are parallel to each other, are arranged outside the exposure path so that these grooves 42A and 42B are aligned with each other, and both sides of an insertion tool 46 are removably fitted into the grooves 42A and 42B. . The insertion tool 46 has a rectangular upper plate 48 and a lower plate 50 connected at one end with a thread 51. An opening 50A is provided in the center of the lower plate 50. A U-shaped frame member 5 has a permanent magnet formed on the edge of the lower plate 50.
2 are fixed in opposition to each other, and are used for positioning the copy photographic paper 16 and for attracting the upper plate 48.

The apparatus constructed as described above is controlled by a microcomputer 58 equipped with an input/output interface, as shown in FIG. The microcomputer 58 is configured to receive signals from the light receiver 38, and receives the transmission density of the color film 13 and the reflection of the copy photographic paper 16 (see FIG. 2) loaded on the photographic paper holder 40. While measuring the concentration, the shutter 34
It is now possible to perform the opening/closing operation. If an abnormality is detected in the shutter 34, the microcomputer 58 activates the buzzer 60.
And an alarm signal is output to the lamp 62. These alarms can be reset by signals from the alarm reset switch 64. Also,
The microcomputer 58 is also capable of correcting the exposure amount based on input signals from the keyboard 66.

Next, the operation of this embodiment configured as described above will be explained.

First, the film transmission density of the color film 13 will be explained. As shown in FIG. 3 (positions corresponding to the color film 13, photographic paper 14, and reflective surface 37 are indicated as 13P, 14P, and 37P, respectively), the light at the reflective surface 37 is out of focus. That is, points A, B, and C of the image are respectively focused on points A' and B'C' of the photographic paper 14, but
The reflective surface 37 has widths l, m, and n. Furthermore, these widths l, m, and n overlap each other.
Therefore, by photometering such out-of-focus light, it is possible to measure the density of the averaged film image. Therefore, the measured concentration is
It is possible to measure the film transmission density with sufficient accuracy with one photoreceiver 38 for each of cyan, magenta, and yellow, regardless of the arrangement (orientation) of the photodetector 8.

Next, a flow chart of the control of the microcomputer 58 shown in FIG. 4 will be explained with reference to the time chart shown in FIG. In addition, for example,
(Step 100) is abbreviated as (100). Further, for the sake of simplicity, the three light receivers are represented by one, and the control of the cut filters 22, 24, and 26 is also omitted.

After waiting for the preparation between the shutters to be completed (100), the amount of light received is read from the light receiver 38 (FIG. 5A), and this value is set as E (102). Next, timer X is started (104) and rotary solenoid 36 is turned on (fifth
(Fig. b) to open the shutter 34 (106). Next, wait for τ msec (a time slightly longer than the time required for the shutter 34 to be fully open, for example 30 msec) to elapse (108), read the amount of light received from the light receiver 38 again (Fig. 5C), and then Let the value be ε (110). This ε is an offset value. I=E-
Determine ε (112) and correct the amount of received light.

This allows the light receiver 3 to change as the ambient temperature changes.
Even if the offset value of 8 changes, the amount of received light can be read accurately.

Next, if I>δ (δ is a constant), that is, the operation of the shutter 34 is normal (114), the shutter open time (time from solenoid on to off) T is calculated from the value of I (116). . The value of this T is
This is sufficiently longer than the processing time of steps 108-116. Next, after waiting for the time Tmsec started in step 104 to elapse (118), the rotor solenoid 36 is turned off (120). Then, the process returns to step 100 and repeats the above process.

In step 114, if I≦δ, that is, the difference between E and ε is less than the fixed value δ, it is considered that the shutter 34 is not fully open, and the buzzer 60 is sounded and the lamp 62 is lit to stop the shutter 34 from operating. Inform the operator of the abnormality (122). Next, after waiting for the operator to confirm this and turn on the reset switch 64 (124), the buzzer 60 and lamp 62 are turned off (126). Then, the process returns to step 100 at the beginning.

In this way, abnormalities in shutter operation can be easily detected.

In fact, in step 116, the cutting time of the complementary color by the cut filter is also calculated, and furthermore, in step 118, the cut filter is also controlled.

Further, in consideration of the minute amount of light received by the light receiver 38 when the shutter is open, a minute value Δ proportional to the luminous intensity of the light source 12 may be further subtracted from E in step 106. This Δ may be calculated from an empirical formula of the value of ε for the value of E read each time.

Next, a copy print (which will serve as a reference)
Exposure correction to create the following will be explained.

As shown in FIG. 2, the photocopy paper 16 is inserted into the insertion tool 46 with the image surface facing downward, and then inserted into the grooves of the rails 42 and 44. This copy photographic paper 16 can be
Color film 13 with reference original picture taken on photographic paper 1
It is made by printing on a 4-color paper, and is called purpose-made photocopying paper. Next, by operating the keyboard 66, the reflected print density X of the copy photographic paper 16 is measured using the light receiver 38. Next, in place of the target copy photographic paper, a copy photographic paper 16A under the current conditions (including development processing) of the photographic printing apparatus for the reference original is loaded onto the photographic paper loading section 40 in the same manner as described above. Next, operate the keyboard 66 and use the light receiver 38 to copy the photographic paper 16.
Measure the reflection print density Y of A. The microcomputer 58 calculates an exposure amount correction value F(X, Y) from the reflection print density values X and Y. This new correction makes it possible to make purpose-copy prints under current conditions.

This correction amount is an exposure amount correction value for producing an optimal print under the current conditions.

In addition, instead of using a color film with a reference original image on it, the color correction filters 20, 22, and 24 are activated to create a reference light, and this reference light is exposed to photographic paper to carry out photographic processing and the photographic paper is mounted. Part 40
By attaching it to a camera and measuring the density of reflective photographic paper, it is possible to measure the state of the print under the current conditions. Even if this measured value is compared with a predetermined value stored in advance or a value measured by attaching a reference (obtained in the same manner under optimal conditions) to the photographic paper loading section 40, the exposure amount is corrected. The value can be calculated.

By setting up a photoprinting device based on this exposure amount correction value, it becomes possible to obtain optimal prints under the current conditions.

[Effects of the Invention] The photographic printing apparatus according to the present invention can
The LATD has excellent effects in that photometry is possible, the photoreceiver can be calibrated in accordance with the shutter operation, and shutter malfunctions can be detected.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a perspective view of a photographic paper loading section, FIG. 3 is an explanatory diagram for measuring film transmission density, and FIG. 4 is a flow chart showing a control flow. FIG. 5 is a time chart corresponding to the control flow described above, and FIG. 6 is a schematic diagram showing a conventional photographic printing apparatus. 12... Light source, 13... Shutter, 36... Rotary solenoid, 37... Reflective surface, 38...
Light receiver, 58...Microcomputer, 60...
…buzzer.

Claims (1)

[Claims] 1. A photographic printing device that determines the exposure amount from the cumulative transmission density of the film and performs printing based on the determined exposure amount, and includes a reflective surface provided on the film side surface of the shutter and a light source outside the exposure path. a light receiver disposed facing the reflective surface when the shutter is closed to measure the cumulative transmission density of the film; a light shielding means for blocking external light to the light receiver; If the difference between this correction amount and the amount of light received when the shutter is closed is less than a preset value, it is determined that the shutter is malfunctioning. A photo printing device characterized by issuing an alarm.