JPS6239858A - Timer device for instant film development - Google Patents

Abstract

PURPOSE:To improve operability by calculating and displaying an appropriate developing time from data previously storing a type set by a film type setting means and an ambient temperature detected by a temperature detecting means. CONSTITUTION:A microcomputer 10 acting as both developing time calculating means and timer means is controlled by a CPU 13. Data on the temperature and developing time corresponding to any types of films is stored in a ROM 11, while data on a film having different developing time and a different temperature correcting coefficient is newly registered in the RAM at any time. The film type setting means 16 and the temperature detecting means 17 set the type of films and the ambient temperature, respectively. The computer 10 reads each inputted data, calculates the appropriate developing time Dt and displays its value in units of second on a display 19. When at timer starting switch S is turned on, a timer 14 acts and the value on the display 19 is subtracted to coem to zero. Then an electronic buzzer 20 is operated. Thus operability can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a timer device for instant film development that is capable of calculating and displaying the appropriate development time for instant film, as well as notifying the completion point of development by sound. .

[Conventional technology]

Generally, it is well known that film development time varies greatly depending on temperature, but in the case of instant film in particular, the temperature at the location where the film was taken corresponds to the development temperature, so it is necessary to develop the film in a dedicated darkroom where the temperature can be easily controlled. Compared to ordinary films that undergo development processing, the development temperature changes over a significantly wider range.

Furthermore, instant film, regardless of whether it is monochrome or color, has an extremely narrow film latitude, so optimizing the exposure time and development time are important factors in obtaining good photographs.

These developing times also differ depending on the type of film.

Figures 5(a), (b), and (c) illustrate the relationship between the developing temperature and developing time for different types of instant films, and (a) and (b) illustrate the relationship between the developing temperature and developing time for different types of instant films. For film, (c) is for color film,
In the case of (C), it is necessary to adjust the exposure not only by adjusting the development time but also by adjusting the aperture or exposure time depending on the temperature.

Conventionally, to adjust the developing time as described above, the photographer generally relied on a thermometer or intuition to determine the temperature, read the developing time corresponding to this temperature from the film instruction manual, and then
This was done by using one's own clock to know when development was complete.

Therefore, when using the so-called Beer-Apart method instant film, in which development begins when the instant film is pulled out of the film holder after shooting and ends when the printing paper is peeled off from the negative, it is difficult to judge the appropriate development time. In addition, it is easy to forget to measure the time taken after the film is pulled out, so images often turn gray and have low contrast due to insufficient development, and the gradation of dark areas becomes unclear due to overdevelopment. there were.

Therefore, a film holder for storing instant film with a timer device attached to the back is also commercially available, and the state in which this film holder is attached to an instant camera is shown in FIGS. 6 and 7.

A timer device 2 is attached to the back of this film holder 1, and by pressing set buttons 3 and 4, 10
The development time can be digitally displayed on the display 5 by setting the digit and single digit numbers from 0 to 9 and a maximum of 99 seconds.

In actual use, the photographer reads the optimum development time corresponding to the type of film used, temperature, etc. from the instruction manual, and presses the set buttons 3 and 4 while looking at the display 5 for the development time. Set by.

A beer-apart type instant film pack is loaded into this film holder 1, and the film is attached to the back side of an instant camera 7 as shown in the figure to take pictures.

Each time one film is shot, the film holder 1
When you pull out the white tab 8 that is slightly sticking out in the direction of arrow P,
As shown by the imaginary line, the yellow tab 9 comes out of the slot, and by slowly pulling it out, the instant film is pulled out, at which time the built-in developer is diffused and development begins.

Therefore, if you immediately press the start button 6 of the timer device 2,
Counting of the developing time is started, and the number displayed on the display 5 is sequentially decremented, and when it reaches 0 seconds, a signal sound is emitted, indicating that the developing has been completed.

The photographer then peels off the film printing paper from the negative to complete the development and complete the photograph.

[Problem that the invention aims to solve]

However, with conventional timer devices, the photographer first measures the temperature, reads the appropriate developing time for the film used corresponding to that temperature from the instruction manual, sets that time each time, and then This requires an extremely complicated operation of pressing the timer start button when the exposed instant film is pulled out of the film holder.

SUMMARY OF THE INVENTION It is an object of the present invention to solve these conventional problems and provide an instant film development timer device that eliminates the need to determine and set the appropriate development time each time a photograph is taken.

[Means for Solving the Problems] Therefore, the instant film development timer device according to the present invention includes film type setting means for setting the type of instant film to be used, temperature detection means for detecting the ambient temperature, and each of these. A developing time calculating means for calculating an appropriate developing time based on a signal from the means, a display means for displaying the calculated developing time, a timer means for measuring the actual developing time, and a timer means for measuring the developing time. The apparatus includes a timer starting means for starting measurement, and a sounding means for generating a signal sound when the time measured by the timer means reaches the developing time calculated by the developing time calculating means.

[For production]

This instant film development timer device determines the appropriate development time based on the data stored in advance by the development time calculation means, depending on the type of instant film set by the film type setting means and the ambient temperature detected by the temperature detection means. It is calculated and displayed on the display.

Then, when the film is taken out after photographing, the timer means for measuring the actual development time is simply started, and when the proper development time has elapsed, the sounding means emits a signal to notify the user.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 4 of the accompanying drawings.

FIG. 1 is a block circuit diagram showing the configuration of a timer device according to the present invention, in which numeral 10 is a microcomputer that functions as development time calculation means and timer means, ROM 11.
RAM12. It consists of a CPU 13° timer 14 and T1015.

The ROMII is pre-stored with temperature and development time data corresponding to various films as shown in Fig. 5, and new films with different development times and/or temperature correction coefficients are released on the market. If the data is stored in the RAM 12, the user can register the data in the RAM 12 at any time.

Further, the film type setting means 16 is configured to automatically set the type of film to be used when the operator manually sets the type of film to be used, and to automatically set the type of film by reading the type signal provided on each film.
15 may be entered.

The temperature detection means 17 is composed of a temperature sensor such as a thermistor, and automatically measures the ambient temperature during development, and the detection signal is A/D converted by the A/D converter 18 and sent to T1015.
is input.

In this embodiment, when a power switch (not shown) is turned on, the microcomputer 10 reads and calculates each input data, calculates the appropriate development time Dt, and displays the value in seconds on the display. do. As a display device, it is preferable to use a liquid crystal display device, which consumes very little power.

Then, when the timer start switch S is turned on, the timer 14 starts measuring the actual development time by counting clock pulses, and sequentially subtracts the development time displayed on the display on the 1st day. When it becomes O, electronic buzzer 2
0, a signal sound is generated to notify the completion of development.

FIG. 2 shows the appearance of an embodiment in which this timer device is attached to a film holder 1 similar to that shown in FIGS. 6 and 7.

This timer device 21 includes a film type setting knob 22 and a power switch 23 for manually setting the type of film to be used to one of the three ranked types A, B, and C.
A push button 24 for a timer start switch S, a display window for one day, and an electronic buzzer 20 for notifying the completion of development are provided.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG.

When the power switch 23 is turned on, this timer device starts operating. First, in step 1, the timer 14 is reset, and in step 2, the instant film type set by the film type setting knob 22 and the temperature detection means 17 are set. Load the detected temperature and step 3
Calculate the appropriate development time Dt. When the push button 24 is pressed and the timer start switch S is turned on, the process proceeds from step 4 to step 5, and the development time D calculated in step 3 is
Set t to timer 14 and start it, step 6
to display the timer value, and in step 7, the measurement time Ct is 0.
In step 8, the clock pulses are counted down from the set value until .

When the measured time Ct of the timer reaches O, a buzzer drive signal is output in step 9, a signal sound is generated by the electronic buzzer 20 to notify the completion of development, and it is determined in step 10 whether a predetermined time has elapsed. , when a predetermined period of time has elapsed, the output of the buzzer drive signal is stopped in step 11 and the process returns to step 2.

In the above embodiment, the timer 14 starts measuring the developing time using a manual push-button switch, but another embodiment of the present invention is capable of automatically starting the measurement of the developing time using the timer 14 in conjunction with the film being pulled out. FIG. 4 shows an example of how the timer start switch is installed.

A normally open timer start switch S is provided inside the film holder 1, and its movable contact piece 25 made of an elastic metal piece is pushed by the side surface 9a of the yellow tab 9 attached to the film when the film is pulled out, and the fixed contact piece 26 The switch S is arranged so that the switch S is turned on when it comes into contact with the switch S.

According to this embodiment, when the yellow tab 9a is pulled out from the film holder 1 in the direction of arrow P after photographing, the timer 14 is automatically started and starts measuring the developing time, resulting in extremely good operability. At the same time, there is no possibility that the user forgets to operate the push button 24 shown in FIG. 2 and the development start point becomes unclear.

The instant film development timer device according to the present invention may be attached not only to the film cassette, but also to the instant camera body, or may be carried alone.

〔Effect of the invention〕

As described above, the instant film development timer device according to the present invention calculates the appropriate development time corresponding to the temperature at the time of shooting by simply setting the type of instant film to be used, and from the time when the film is pulled out to the time when development is completed. In addition to displaying the time required for development, just by starting the timer means, a signal sound is generated to notify you when development is complete, greatly improving operability and preventing failures due to inappropriate development time. can do.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram of an embodiment of the present invention, Fig. 2 is a diagram showing the external appearance when the timer device is attached to a cassette holder, and Fig. 3 is a diagram showing the appearance of the timer device as shown in Figs. 1 and 2. Flowchart diagram showing the operation of the embodiment; FIG. 4 is a plan view showing the state in which the timer start switch is installed inside the film holder in another embodiment of the present invention; FIGS. 5(a), (b), (c) 6 and 7 are diagrams showing the relationship between temperature and development time for different types of instant film, respectively. FIGS. 6 and 7 are front and rear perspective views showing an instant camera equipped with a film holder equipped with a conventional timer device. It is. 1... Film holder 7... Instant camera 8... White tab 9... Yellow tab 10...
・Microcomputer 14...Timer 16...Film type setting means 17...Temperature detection means 1st...Indicator 20・
...Electronic buzzer 21...Timer device 22...
Film type setting knob 23...Power switch 24...Timer start switch push button S...Timer start switch (Figure 5) Temperature (Th℃) Temperature (Th℃)

Claims (1)

[Claims] 1. A film type setting means for setting the type of instant film to be used, a temperature detection means for detecting the ambient temperature, and a setting signal from the film type setting means and a temperature detection signal from the temperature detection means. a development time calculation means for calculating an appropriate development time based on the development time; a display means for displaying the development time calculated by the development time calculation means;
a timer means for measuring the actual development time; a timer start means for causing the timer means to start measuring the development time; and a timer means for causing the timer means to start measuring the development time; A timer device for instant film development, comprising a sounding means that generates a signal sound at certain times. 2. The timer device for instant film development according to claim 1, wherein the timer starting means is a manual switch. 3. The timer device for instant film development according to claim 1, wherein the timer starting means is a switch activated upon detecting that the instant film is pulled out from the film holder.