JPH01237659A - Method of controlling drying temperature of photographic film - Google Patents

Abstract

PURPOSE:To maintain the size of a photographic film after drying at the size at the time of exposing by controlling the inside of a drying chamber to the optimum drying state temp. or below at which the moisture content of the photographic film does not change when the photographic film right after emission from the drying chamber is rested in working environment. CONSTITUTION:The photographic film has the moisture content in nearly equal. with the humidity in the working environment in case of subjecting the photographic film to the exposing. The photographic film elongates by absorbing moisture when this photographic film is subjected to development processing, etc. The emulsion layers and backing layer attain the elongated state at the time of the drying when the film is dried at the temp. above the optimum drying temp. but the emulsion layers and backing layer are not elongated in the drying chamber and, therefore, the elastic force of both the layers is not lost when the film is dried at the optimum drying temp. The photographic film is thus restored to the size at the time of the exposing by the elastic force and the generation of a dimensional error in the film at the time of the exposing and at the time of the drying is obviated. The optimum dry state is thereby obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] [Prior Art] In a photographic film drying device used in the drying chamber of an automatic processor, when the power of the automatic processor is turned on, The fan and heater are turned on to heat the inside of the drying chamber.

In this case, regardless of the temperature and humidity of the outside air, the outside air taken in from the outside air intake is heated by a heater to create drying air, which lowers the relative humidity and increases the temperature of the film to be dried. Air containing moisture is exhausted to the outside of the machine.

[Problem that the invention seeks to solve]

However, when drying a film using such an apparatus, the following problems arise if the temperature and humidity of the outside air are ignored. That is, as shown in FIG. 6, the film 81 is made of polyester film base (hereinafter P
ET 82, an emulsion layer 84 coated on one side of the PET 82, and a backing layer 86 made of gelatin and dye coated on the other side.

It is known that the dimensions of this film 81 change due to heat and moisture like any other substance.However, the dimensions of the film 81 when exposed (point P in Figure 7) and the dimensions of the film after drying are known. If the dimensions are the same (point Ao in Figure 7), there is no problem even if the dimensions change in the middle (during the development process shown at point W in Figure 7), but as shown by the imaginary line in Figure 6, the film When 81 contains a lot of water due to development processing, etc., the gelatin-containing layers 84 and 86 lose their elasticity and become substantially P.
Only the elongation of ET82 is observed.

When the next step, drying treatment, is performed in this state, each layer will shrink, but different amounts of shrinkage will occur as shown by the dotted lines in Figure 6. In this case as well, PE
T82 limits the amount of shrinkage of emulsion layer 84 and backing layer 86, which in turn causes them to remain stretched.

As the emulsion layer 84 and the backing layer 86 are stretched in this way, they lose their elasticity and do not return to their original dimensions even if the temperature and moisture content reach the pre-development temperature and remain stable in the stretched state upon drying. This results in an error in film dimensions at the time of exposure (see dimension G in FIG. 7).

The object of the present invention is to maintain the dimensions of a photographic film after drying to the dimensions at the time of exposure processing, in consideration of the above facts.

[Means for solving problems]

The photographic film drying temperature control method according to the present invention detects the temperature and humidity of the working environment introduced into the drying chamber when supplying drying air into the drying chamber, and controls the temperature of the drying air based on this temperature and humidity. A photographic film drying temperature control method for drying photographic film, wherein the temperature in the drying chamber is set to below the optimum drying temperature at which the moisture content of the photographic film does not change when the photographic film is left in a working environment immediately after leaving the drying chamber. It is characterized by control.

[Effect]

When photographic film is subjected to exposure processing, the film has a water content that is almost in equilibrium with the humidity of the working environment. When this photographic film is developed, it absorbs moisture and stretches. Next, when drying is performed at a temperature higher than the optimum drying temperature, the emulsion layer and backing layer shown in the prior art section are stretched during the drying process, but when drying is performed at the optimum drying temperature, the emulsion layer and backing layer are stretched in the drying chamber. The layer and the backing layer are not stretched and therefore do not lose their elasticity. Therefore, the photographic film can elastically return to its dimensions at the time of exposure, and no dimensional errors occur between the time of exposure and after drying, and an optimal dry state can be obtained.

Note that as long as the temperature inside the drying chamber is below the optimum drying temperature, the lower the better. Immediately after leaving the drying chamber, the film contains more moisture than the equilibrium moisture content in the working environment, but the films will adhere to each other. It is necessary that the photographic film does not contain enough moisture to cause the film to dry, and that the temperature is higher than the temperature at which the photographic film is left in an optimal dry state for a predetermined period of time after leaving the drying chamber.

〔Example〕

FIG. 1 shows a schematic structure of an automatic processor 10, which is a photographic film processor.

The film 14 transported from the entrance 12 into the automatic developing machine 10 is guided by a guide roller 16, passes through a developing tank 18, a fixing tank 20, a washing tank 22, and then reaches a drying chamber 24. Developing tank 18, fixing tank 20 and washing tank 22
A rack 28 constituted by a plurality of guide rollers 26 is housed inside, and the film 14 is immersed by this rack 28 from the liquid surface to the bottom of the eight tanks, turned over, and guided to the liquid surface again. ing.

Also, between the developer tank 18 and the fixing tank 20, and between the fixing tank 20
A guide roller 30 is disposed between the washing tank 22 and the washing tank 22, and the film 14 is guided to the adjacent tank in sequence, and a plurality of roller pairs 32 are arranged between the washing tank 22 and the drying chamber 24. The film 14 is guided to the drying chamber 24. Note that these roller pairs 32 also have the function of squeezing some of the water adhering to the film 14.

A plurality of conveyance rollers 34 are arranged in the drying chamber 24 evenly in the vertical direction in FIG. It is being transported. A guide plate 36 is installed at the bottom of the drying chamber 24.
is arranged so that the film 14 is turned toward the right side wall of the developing machine frame 10A in FIG. .

A motor 42 is attached to the drive roller 38 via a belt 44, and the driving force of this motor 42 drives the drive roller 38.
is rotating. The rollers disposed in the automatic developing machine 10 are connected to the drive roller 38 by a chain or belt (not shown), and are driven to rotate simultaneously.

The drying chamber 24 has an air intake duct 46 in a part of its partition wall 24A.
and an exhaust duct 48 are attached to communicate with the outside of the automatic processor 10. A heater 50 is installed in the intake duct 46.
A fan 52 is provided, and after the outside air introduced into the intake duct 46 by the fan 52 is heated by the heater 50, this drying air is supplied to the drying chamber 24.

From the exhaust duct 48, the film 14 due to the drying air is removed.
The moist air after the transport roller 34 is dried is discharged to the outside of the automatic developing machine 10.

Here, in the drying chamber 24, a drying air temperature detection sensor 54 is provided.
is equipped to detect the temperature of the drying air. Further, an outside air temperature detection sensor 56 for detecting the temperature of the outside air and an outside air humidity detection sensor 58 for detecting the humidity of the outside air are disposed on the outer surface of the automatic processor frame 10A. Furthermore, a plurality of film detectors 60 arranged in the width direction of the film 140 are arranged near the insertion opening 12,
The conveyance interval of the film 14 inserted into the automatic developing machine 10 is detected as the throughput of the film 14. That is, although this embodiment assumes that the film 14 is processed at regular intervals, for example, when the film 14 is processed at shorter intervals than the above-mentioned regular interval, or when a large amount of film 14 is processed, Incidental control is performed to maintain the preconditions, such as detecting this with the film detector 60 and providing an interval until the temperature in the drying chamber reaches a temperature that allows drying.

dry air temperature detection sensor 54, outside air temperature detection sensor 56,
The outside air humidity detection sensor and film detector 60 are input to a control device 62 .

As shown in FIG. 2, the control device 62 includes a CPU 64, R
A microcomputer 74 consisting of an AM66, a ROM68, an input port door 0, and an output port door 2;
D converter 76, analog gate 78, and driver 80
It is equipped with

dry air temperature detection sensor 54, outside air temperature detection sensor 56,
The outside air humidity detection sensor 58 is connected to the input side of the analog gate 78, and is connected to the input port door 0 of the microcomputer 74 via the A/D converter 76. Also,
A film compensator 60 is connected to the input boat.

The motor 42, heater 50, and fan 52 are connected to the driver 80.
are connected to the output side of the output port 2, and are each driven by a control signal from the output port door 2.

Here, the temperature inside the drying chamber 24 is determined by the temperature and humidity of the outside air. Its characteristic diagram is shown in FIG. This characteristic diagram shows the film 1 based on the outside air humidity.
4 shows the maximum temperature at which overdrying does not occur for each outside air temperature, and is the optimum drying temperature curve when setting the drying temperature. Based on this optimal drying temperature curve, the RAM 66 of the microcomputer 74 stores a map showing the relationship between the detected value of the outside air humidity detection sensor 58 and the temperature inside the drying chamber, as shown in FIG. . Note that this map is provided for each outside air temperature, but for example, outside air temperature 2
The map at 5°C is shown.

Graph A in FIG. 5 is the optimal drying curve shown in FIG. will be done. That is, since the moisture contained in the film 14 at the time of exposure is determined by the humidity of the outside air, by deducting the amount of moisture and drying the film 14, the outside air humidity and the moisture content of the film 14 can be brought into equilibrium. Curve A is a characteristic diagram determined based on experimental results, etc., and by controlling the temperature inside the drying chamber based on this, an optimum drying state is obtained.

Next, curve B is a minimum drying curve showing the lowest level at which the film 14 does not become undried. At a temperature in the drying chamber 24 below this, the film 14 after drying becomes undried, and the films 14 are stacked on top of each other. It will be glued. Therefore, in this example, at least this minimum drying curve (
The temperature inside the drying chamber is controlled to a semi-dry region where the temperature is above curve B) in FIG. 5 and below the optimum drying curve (curve A in FIG. 5).

At temperatures close to the curve in semi-arid regions,
Immediately after drying, the moisture content is slightly higher than during exposure, but by leaving it in a working environment (about 2 to 30 minutes), it can be brought into a state of almost equilibrium with the humidity of the outside air.

As shown in FIG. 5, along the curve, an upper limit value and a lower limit value are set for the set temperature in the drying chamber 24 with respect to the outside air humidity, irrespective of the working environment humidity. The upper limit is about 70° C., and if the temperature in the drying chamber is increased more than this, there is a risk that the film 14 will be deformed, and it is necessary to prevent undrying by other means such as slowing down the drying process speed.

Further, the lower limit value is determined by the temperature of the outside air, and setting the temperature inside the drying chamber below the temperature of the outside air essentially results in cooling. In theory, installing a cooling device to lower the drying temperature to below the ambient temperature will give the best results (in terms of dimensional stability), but this is a major constraint, such as requiring a large space on the device, so in practice Difficult and undesirable. In this case, it is also effective to prevent overdrying by other means such as stopping the heater 50 and fan 52 or increasing the drying speed.

Here, in this example, the optimum drying curve (curve A in Fig. 5)
An α curve is provided in which the temperature is shifted to the overdry side.

This α curve indicates the allowable range on the over-dry side of the optimal drying curve.If the temperature is below this α-curve, even if slightly over-dried, the dimensional error can be practically ignored (before and after treatment). The dimensional change rate is 0.005%). The temperature difference between this α curve and the optimal temperature curve is +7
It is ℃.

Next, the software configuration of the microcomputer 74 will be explained with reference to FIG.

When the automatic developing machine 10 is turned on, the program starts. First, in step 100, the heater 50
, the fan 52 is controlled on and off to preheat the inside of the drying chamber 23.

Next, the process proceeds to step 104, where the outside air humidity sensor 58 detects the humidity of the outside air, and then, at step 106, the outside air temperature sensor 56 detects the outside air temperature, and step 108.
Move to.

Next, the temperature T of the drying chamber 24 necessary for drying the film is determined from the map shown in FIG. 5 from the data values read in step 108.

Next, in step 110, the detected temperature data t2 from the drying air temperature sensor 54 is read, and in step 112, the required drying temperature T and t2 are compared.

If Tf-t2, the process advances to the next step 114, where the heater 50 is controlled on and off according to the value of the required drying temperature T, and then the drying room temperature control routine ends. If T=t2, step 114 is skipped and this routine ends.

In this way, in this embodiment, the temperature inside the drying chamber 24 is not only determined based on the outside air temperature, but also the temperature inside the drying chamber 24 is determined based on the humidity of the outside air. Therefore, the temperature inside the drying chamber 24 does not have to be set to a high temperature, and as a result, the drying state of the film 14 does not become excessively dry. By preventing over-drying, the elasticity of the film 14 is not lost, and even if there is a slight dimensional change during the development process, it can return to the original dimensions after drying, ensuring good dimensional accuracy. Obtainable.

In addition, in this example, a predetermined width (
Since it has a semi-dry region), temperature control is easy and simple on/off control can be applied. In this case, the moisture content of the film 14 may be slightly higher than the outside air humidity immediately after the drying process, but there is no problem because the film 14 becomes dry in a short time (about 2 to 30 minutes).

〔Effect of the invention〕

As explained above, the photographic film drying temperature control method according to the present invention has the excellent effect that the dimensions of the photographic film after drying can be maintained at the dimensions at the time of exposure processing.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of an automatic developing machine to which an embodiment of the present invention is applied, Fig. 2 is a control block diagram, Fig. 3 is a control flow chart, Fig. 4 is an optimum drying temperature characteristic diagram, and Fig. 5 is FIG. 6 is a cross-sectional view of the film, and FIG. 7 is a characteristic diagram showing dimensional changes of the film. DESCRIPTION OF SYMBOLS 10... Automatic developing machine, 141... Film, 24... Drying room, 50... Heater, 52... Fan, 54... Dry air temperature detection sensor, 56... Outside air temperature detection sensor , 58...Outside air humidity detection sensor.

Claims (5)

[Claims] (1) When supplying drying air to the drying room, the temperature and humidity of the working environment taken into the drying room is detected, and the temperature of the drying air is controlled based on this temperature and humidity to dry the photographic film.Photographic film drying temperature 1. A control method for photographic film, comprising controlling the inside of the drying chamber to an optimum drying temperature at which the moisture content of the photographic film does not change when the photographic film is left in a working environment immediately after leaving the drying chamber. Drying temperature control method. (2) The optimum dry state temperature has a predetermined tolerance range on the high temperature side.
) Photographic film drying temperature control method described. (3) Immediately after leaving the drying chamber, the interior of the drying chamber contains more moisture than the equilibrium moisture content under the working environment, but does not contain enough moisture to cause the films to adhere to each other, and after drying 3. The method of controlling a drying temperature of a photographic film according to claim 1, wherein the lower limit temperature is controlled to be higher than the temperature at which the optimum drying state is reached within a predetermined time period when the photographic film is left to stand. (4) Photographic film drying temperature control according to any one of claims (1) to (3), characterized in that the temperature in the drying chamber is set below a temperature at which the photographic film does not change in size before and after processing in an automatic processor. Method. (5) The photographic film drying temperature control method according to any one of claims (1) to (4), wherein the temperature inside the drying chamber is set to a minimum value equal to the outside air temperature.