JPH02157754A - Drying method - Google Patents

Abstract

PURPOSE:To shorten drying time without generating a defect in film quality such as reticulation on the emulsion surface of a photosensitive material by stopping heating before the point when the moisture content in the emulsion layers of the photosensitive material attains equil. CONSTITUTION:A curve A is obtd. by actual measurement with temp. sensors 6a to 6h in the basic pattern of turning, for example, heating sources 51 to 53 on and turning a heating source 54 off. Namely, the surface temp. of the photosensitive material is equal to the wet bulb temp. of the air in a drying chamber and is about 35 to 40 deg.C in the constant rate drying period of the high moisture content. A partly dried part is generated in the emulsion layers and the surface temp. rises when the moisture content in the emulsion layers decreases and the drying shifts to decreased rate drying. The characteristic of the photosensitive material changes from out curling to in curling when the surface temp. approaches the dry bulb temp. of the air. This point is the drying point. The photosensitive material S is rapidly heated and dried in this way under the optimum conditions. The drying time is thus shortened and the defect in the film quality, such as reticulation, of the emulsion surface Sa is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a drying method for drying a photosensitive material after wet processing.

<Prior Art> Photosensitive material processing apparatuses that perform wet processing include, for example, silver salt photocopiers, automatic processors, and the like.

A silver halide photocopier uses photosensitive material (
The exposed photosensitive material is sent to the exposure section for exposure, and the exposed photosensitive material is sent to the processing section where it is sequentially developed, bleached/fixed, and washed with water.The photosensitive material is then dried in the drying section to produce the original image. You will obtain a copy of the

In addition, an automatic processor sequentially develops, bleaches, fixes, washes, and stabilizes photographed photosensitive material (film) in a processing section, then dries the photosensitive material in a drying section to produce a negative or positive image. (It is the one that gets the elephant.

Incidentally, in recent years, due to the demand for large-scale processing, it has been desired to shorten the processing time, and it has become an issue to shorten the drying time in the drying section, which affects the overall processing time.

FIG. 3 shows a drying device installed in the drying section of the photosensitive material processing apparatus, particularly an automatic processor.

The drying device 10a shown in the figure has first, second and third drying chambers 11, 12 and 13 partitioned by a partition wall 14, and each drying chamber has a vine dryer 15 that supplies hot air.
is installed.

Further, this drying device 10a has a conveying means composed of conveying rollers 16 and 17 installed at the top and bottom of each of the drying chambers 11 to 13, respectively. The material S is transferred to the 1st I2 drying chamber 11-
The emulsion surface Sa of the photosensitive material S is dried by blowing hot air from an opening 151 formed in the duct of the dryer 15 while being transported in the order of the second drying chamber 12 to the third drying chamber 13.

In such a drying apparatus 10a, by controlling the drying temperature for each of the drying chambers 11 to 13, drying efficiency can be increased and drying time can be further shortened.

That is, if the drying temperature is increased in all of the drying chambers 11 to 13, the drying time will be shortened.

However, in this case, reticulation (
There is a drawback that film quality defects such as cracks occur.

Conversely, if the drying temperature is lowered in all of the drying chambers 11 to 13, the above-mentioned reticulation and the like will not occur, but the drying time will become longer.

Therefore, it is conceivable to increase the drying temperature in the first drying chamber, which is the early stage of drying, and to lower the drying temperature in the third drying chamber 13, which is the latter stage of drying.

However, even in this case, the drying time is only slightly shortened, and the occurrence of reticulation etc. is not completely prevented.

As described above, with the conventional drying apparatus 10a, it is difficult to simultaneously shorten the drying time and prevent film quality defects such as reticle erosion. The current situation is that this has not been achieved.

Furthermore, in the drying device 10a, each drying chamber 11 is designed to maintain a balance (compromise) between shortening the drying time and preventing poor film quality.
Adjustment and management of the drying temperature in -13 was done empirically, and required skill and was time-consuming. In particular, the drying behavior of photosensitive materials differs depending on various factors such as the type of photosensitive material, its area, the degree of moisture before drying, the temperature inside and outside the drying room, and the humidity. must be performed each time according to the above conditions.

However, at present, such management is not carried out.
Therefore, there is a problem that the quality of the dried photosensitive material, especially the properties of the emulsion surface, becomes non-uniform.

<Problems to be Solved by the Invention> The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to shorten the drying time without causing film quality defects such as reticle etching on the emulsion surface of a photosensitive material. It is an object of the present invention to provide a drying method in which the quality of a photosensitive material after drying is uniform even if various conditions change.

Means for Solving the Problems> Such objects are achieved by the present invention as described below. Namely, the present invention provides a method for rapidly heating a photosensitive material while transporting the photosensitive material in a wet state in a drying chamber. This drying method is characterized in that heating is stopped before the water content of the emulsion layer of the light-sensitive material reaches equilibrium.

Further, in the drying chamber, a plurality of electromagnetic wave heating devices are installed along the conveyance path of the photosensitive material to detect changes in the surface temperature of the photosensitive material along the conveyance direction of the photosensitive material, and based on this detected value, It is preferable to use a drying method in which a point at which the water content of the emulsion layer reaches equilibrium is determined, and the operation of an electromagnetic wave heating device is stopped after this point is reached.

<Example> Hereinafter, the drying method of the present invention will be described in detail with reference to a preferred example shown in the accompanying drawings.

FIG. 1 is a sectional front view schematically showing an example of the configuration of a drying apparatus for carrying out the drying method of the present invention.

As shown in FIG. 1, the drying device 1 has a casing 2, and a drying chamber 3 is formed within the casing 2. As shown in FIG. Inside the drying chamber 3, there is provided a conveying means 4 preferably composed of driven and rotating conveying rollers 41, 42, 43 and 44, and the photosensitive material S passes through the respective conveying rollers 41 to 44 inside the drying chamber 3. It is designed to be transported along a predetermined route. Note that the conveyance means 4 may include a guide (not shown) installed along the conveyance path in order to guide the photosensitive material or prevent it from swinging.

Moreover, among the conveyance rollers 41 to 44, especially the conveyance roller 4
1 and 42 are located near the far-infrared heater 5, and therefore are preferably made of a heat-resistant material.

Further, the casing 2 is formed with an opening 21 and an outlet 22 for the photosensitive material S.

A far-infrared heater 5, which is a means for heating the photosensitive material, is installed between the conveyance rollers 41 and 42 on the right side in the drawing in the drying chamber 3. This far-infrared heater 5 has a configuration in which four heat generating sources 51, 52, 53, and 45 facing the emulsion surface Sa of the photosensitive material S are installed along the conveyance direction of the photosensitive material. The heat generating sources 51 to 54 have a configuration in which heat generating elements are arranged in an array in the width direction of the photosensitive material S.

Examples of the heat generating elements of each of the heat generating sources 51 to 54 include heaters in which the heat source is blocked by an inorganic shield, such as a ceramic heater, a tungsten-containing quartz tube heater, a tungsten-containing glass bulb heater, etc. Preferably, it emits electromagnetic waves (far infrared rays).

Such a far-infrared heater 5 can intensively apply high energy to the surface of the photosensitive material S1.
Since the amount of heat imparted per unit area of the surface is large (for example, about 100 to 20,000 caj/m''-5ec), the photosensitive material S can be heated rapidly.

Note that, unlike the illustration, a similar heat generating source facing the back surface sb of the photosensitive material S may be additionally installed.

Further, the heating means in the present invention is not limited to the far-infrared heater 5, but may also be a far-infrared heater configured to irradiate far-infrared rays toward the emulsion surface Sa of the photosensitive material S and have a vine reflector, or other out-of-field rays. , a heating device, a heat roller, a heat panel, etc. that can apply electromagnetic waves such as microwaves, high-frequency waves, or ultrasonic waves may be used.

Since such a far-infrared heater 5 reaches a high temperature (or generates a large amount of heat), a heat insulating material 25 is provided inside the casing 2.
is installed. Examples of the heat insulating material 25 include asbestos, glass fiber, silica, and volcanic ash.

Note that, unlike the illustrated example, a similar heat insulating material may be provided outside the casing 2, or the entire casing or the portion around the far-infrared heater 5 may be made of a heat insulating material.

As shown in FIG. 1, eight temperature sensors (e.g., infrared surface thermometers, thermocouples, ) 6a, 6b, 6c, 6d, 6e, 6f, 6g and 6h are installed. These temperature sensors 6a~
6h is for detecting the surface temperature of the photosensitive material S at the installation position.

Further, a control means 7 constituted by a microcombinator 121 or the like is installed outside the casing 2, and each temperature sensor 6a to 6h is connected to an input terminal of the control means 7.

On the other hand, relay switches 81, 82, 83,
and 84 are installed, and these relay switches 81 to 84 are installed.
84 is connected to the output terminal of the control means 7.

In addition, a sensor 65 is installed at a predetermined location in the drying chamber 3 (upper left in the figure) to detect the temperature and humidity of the atmosphere in the drying chamber 3.
A sensor 66 is installed outside the casing 2 to detect the temperature and humidity of the outside air.

In the present invention, the types, numbers, installation positions, etc. of the temperature sensors 6a to 6h are not limited to those described above, and the installation of the temperature sensors 6a to 6h and the sensors 65 and 66 is not essential.

Drying is performed using such a drying device 1a in the following manner.

The photosensitive material S introduced into the drying chamber 3 through the entrance 21 of the casing 2 is turned around by about 90 degrees by the conveyance roller 41 and conveyed downward until it reaches the conveyance roller 42 .

Between the conveyance rollers 41 and 42, the emulsion surface Sa of the photosensitive material S is irradiated with far infrared rays by the far infrared heater 5. In this case, since the emulsion surface Sa of the light-sensitive material is intensively heated, drying is performed rapidly at a relatively high drying temperature, and constant rate drying and lapse rate drying are mainly performed.

Thereafter, the photosensitive material S is slowly heated at a low temperature by cooling, residual heat from the far-infrared heater 5, the atmosphere in the drying chamber 3, etc., and is mainly subjected to humidity-controlled drying.

Such a drying method can shorten the drying time and suppress the occurrence of reticulation and the like on the emulsion surface Sa.

The photosensitive material S dried in this manner is transported out of the casing 2 from the outlet 22 via the transport rollers 44.

Each of the heat generating sources 51 to 54 of the far infrared heater 5 is controlled by the control means 7.
The energization (ON) and energization (OFF) are controlled by. The control method will be explained below.

The surface temperature of the photosensitive material S detected at any time or timely by each temperature sensor 6a to 6h is manually inputted to the control section 7, and
A surface temperature change curve as shown in the graph in the figure is retained as data.

In the illustrated configuration example, the surface temperature of the back surface sb of the photosensitive material S is measured, but this temperature is approximately equal to the surface temperature of the emulsion surface Sa or can be converted. The surface temperature of the emulsion surface Sa has a certain relationship with the water content of the emulsion layer at that position. Therefore, by knowing the surface temperature of the back surface sb of the photosensitive material S, the water content of the emulsion layer can be determined.

The relationship between the surface temperature and the water content of the emulsion layer will be explained using the graph shown in FIG.

In normal processing, the surface temperature change curve has the pattern A in the figure. In other words, during the constant rate drying period with high moisture content,
The surface temperature of the photosensitive material is the wet bulb temperature (WB) of the air in the drying room.
The temperature is approximately 35°C to 40°C.

When the water content of the emulsion layer decreases and shifts to lapse rate drying, some dry areas appear in the emulsion layer and the surface temperature increases.

Then, the surface temperature is the dry bulb temperature (i.e. drying temperature) of the air.
When approaching , the properties of the photosensitive material change from out-curl to in-curl. This point is the dry point and is indicated by the arrow in the graph of FIG.

On the other hand, in the control unit 7, the far infrared heater 5 set in advance
A heating control program is stored.

This heating control program includes drying conditions such as drying temperature and transport speed of the photosensitive material, environmental conditions such as temperature and humidity inside and outside the drying chamber 3 (detected by sensors 65 and 66), and humidity of the photosensitive material before drying. size, layer structure, and type of photosensitive material (especially the presence or absence of gelatin on the back side sb)
Depending on various conditions such as the type of processing (continuous processing, small number processing), etc., the basic pattern of ON and OFF of each heat generating source 51 to 54 (a model considered to be optimal) is determined, and the pattern obtained from the above actual measurement is determined. Each of the heat generation a51 to a54(7) ON and oFF is controlled so as to appropriately modify (correct) this basic pattern according to the data of the surface temperature change curve of the photosensitive material S.

For example, under the predetermined conditions, in the graph of FIG.
Assuming that the surface temperature curve of A is an ideal line, to achieve this the heating sources 51,528 and 53 are
A basic pattern of turning off the heat source 54 is determined.

If a curve is obtained by actual measurement with the temperature sensors 6a to 6h, the ON/OFF patterns of the heat generating sources 51 to 54 are maintained as they are (no modification of the basic pattern).

If the actual measured value becomes curve 8 in the graph due to any cause (for example, a 2W degree change in the outside air, or a change in the type of sensitive material), there is insufficient heat, and the heat source 54, which was previously turned off, is In other words, all heat sources 51
~54 is turned on.

On the other hand, if the measured surface 1 degree curve tends to move upwards from the A curve, it means that the amount of heat is too much, so the basic pattern is modified to turn off the heat source 53, that is, the heat source 51 and 52 are turned on, and heat generation sources 53 and 54 are turned off. In particular, if the curve is C, it is judged as an abnormal state, and therefore all heat sources 51
54 to OFF to prevent troubles such as deformation, deterioration, and fire due to overheating of the photosensitive material, and to ensure safety.

Note that each of the heat generating sources 51 to 54 is turned on or off by operating or not operating the corresponding relay switches 81 to 84. That is, the control means 7 outputs an operating current to the relay switch corresponding to the heat generation source that should be turned ON, to bring it into the operating state, and sets the relay switch corresponding to the heat generation source that should be turned OFF to be inoperative. It outputs a current (return current) to put it in a non-operating state (return/door state).

Further, the basic pattern is determined by, for example, storing a table of a large number of test patterns dried under various conditions, and automatically or artificially selecting an appropriate selection from among these. can be mentioned. Alternatively, a method of determining the basic pattern preliminary or empirically may be used.

By carrying out such control, the photosensitive material S is rapidly heated and dried under optimal conditions, and therefore,
It is possible to shorten the drying time and prevent film quality defects such as reticulation on the emulsion surface Sa. Moreover, even if the above-mentioned conditions change, drying is carried out under optimal conditions accordingly, so that the quality of the photosensitive material S after drying, especially the degree of warpage and curvature of the photosensitive material, and the properties of the emulsion surface Sa, are uniform.

In addition, in the present invention, basic patterns of ON and OFF of each heat generation source 51 to 54 are selected according to the above conditions, but modifications to this (feedback from actual measurement values) are made.
It is also possible to have a configuration in which this is not performed. In this case, installation of the temperature sensors 6a to 6h is unnecessary, and the drying device becomes simpler and more compact.

In addition, in the present invention, the ON and OFF of the heat source
Instead of l control, control (proportional control) in which the amount of heat generated (voltage) is varied continuously or stepwise may be used.

The type of photosensitive material S to be dried by the drying method of the present invention is not particularly limited, and examples thereof include color negative film, color reversal film, color photographic paper, color positive film, color reversal photographic paper, photographic material for plate making, and X-ray photography. Examples include various photosensitive materials such as photosensitive materials, black and white negative films, black and white photographic paper, and microphotosensitive materials.

Further, the drying method of the present invention can be applied to various photosensitive material processing apparatuses such as automatic developing machines, wet copying machines, video printer processors, color vapor processing machines for plate inspection, and the like.

Although the preferred configuration example of the drying method of the present invention has been described above, it goes without saying that the present invention is not limited thereto.

<Experiment example> Experimental examples of the present invention will be described below.

(Example 1 of the present invention) Using an automatic developing machine (Model PPll0I manufactured by Fuji Photo Film Co., Ltd.) equipped with a drying device configured as shown in Fig. 1, a processing prescription was applied to Fuji Color Paper Type 2A (manufactured by the same company) as a photosensitive material. The standard treatment of CP-25Q (manufactured by the same company) was performed and dry dog mulberry was applied.

The far-infrared heater in the drying device is a plate-shaped ceramic heater made by Hirano Co., Ltd. that has four heat sources, and its drying temperature (atmosphere temperature around the photosensitive material) is approximately 70°C (the surface temperature of the photosensitive material is (approximately 35 to 40°C). Note that this plate-shaped ceramic heater applies heat of about 5000 caR/1n2-sec per unit area to the surface of the photosensitive material.

The transport path length of the photosensitive material within the casing is approximately 1.
0 m, and the conveyance speed was approximately 1.4 m/min.

In addition, the external environment of the drying equipment is a temperature of 24°C and a humidity of 65%.
It was RH.

In addition, a microcomputer with memory, arithmetic circuits, etc. is used as the control means, and the basic ON/OFF patterns of each heat source are set by selecting the most suitable one from among a large number of test patterns stored in tables in the memory. This was done by selecting items. As a result, from each condition in this experimental example, the curve shown in the graph in Figure 2 is an ideal line, and the basic pattern for obtaining this is to turn on the first three heat sources, and turn on the remaining heat sources. Turn off the heat source of
It became F.

Furthermore, temperature sensors (To-334 manufactured by Matsushita Electric Co., Ltd.
) to measure the surface temperature of the photosensitive material at various locations at any time.
The information was input into a microcomputer and processed to determine the isolation from the curve, and the basic pattern was modified depending on the degree of isolation.

(Example 2 of the present invention) Processing and drying were performed in the same manner as Example 1 of the present invention, except that the drying temperature using the far-infrared cotton heater was set to about 65°C.

(Comparative Example 1) Without performing ON/OFF control of the heat source of the far infrared heater,
Invention example 1 except that the four heat sources were always on.
It was treated and dried in the same manner as above.

(Comparative Example 2) Processing and drying were carried out in the same manner as in Inventive Example 1, except that an automatic developing machine of the same type equipped with a drying device 10b having the configuration shown in FIG. 4 was used.

Note that the drying device 10b shown in the figure has a dryer 15 built into the casing 2. This dryer 1
5, openings 151 are formed in the duct 150 along the transport path of the photosensitive material S, and drying is performed by blowing warm air heated by a heater 152 from each opening 151 toward the emulsion surface Sa of the photosensitive material. It is.

The drying temperature (temperature of air a) in this dryer 15 is:
The temperature was set at 80°C.

In addition, the transport path length of the photosensitive material inside the casing is
The length was approximately 1.2m.

Regarding the photosensitive materials obtained in Invention Example 1.2 and Comparative Example 1.2 (3 examples each), the drying time, the properties of the photosensitive material (deformation, alteration, ignition, etc.) and the reticleation of the emulsion surface were evaluated. We investigated the situation. The results are shown in Table 1 below.
Shown below.

The evaluation method is as follows.

[Drying time] The time required from the start of drying to the drying point was determined.

Note that the drying point can be determined from the properties of the emulsion surface of the light-sensitive material, and is determined as follows.

At the drying process stage, the emulsion layer is raised, but then becomes flat, and as drying progresses, it tends to become depressed, but the point at which the emulsion surface becomes flat can be defined as the drying point.

[Properties of photosensitive material] Inspect the photosensitive material for deformation (warping, bending), deterioration (discoloration due to overheating, blistering, scorching), and presence of ignition.A-H
It was evaluated on a five-point scale.

A: No deformation or alteration B: Slight deformation or alteration C: Deformation or alteration D: Much deformation or alteration E: Ignition [occurrence status of reticulation] Using an optical microscope with a magnification of 50 to 100 times, the emulsion was examined. The surface was cut with 45° illumination light and observed, and evaluated on a five-grade scale from A to E.

A: No cracks B: Some cracks C: Some cracks D: Many cracks E: Quite a lot of cracks Table As is clear from Table 1 above, inventive examples 1 and 2:
In all cases, the drying time was short and the properties of the light-sensitive materials were good, with no reticulation or poor gloss occurring on the emulsion surface.

On the other hand, in Comparative Example 1, deformation of the photosensitive material due to overheating,
Due to the significant deterioration, it was not possible to investigate the occurrence of reticulation, and in Comparative Example 2, the drying time was long,
Furthermore, the occurrence of reticulation was observed.

Next, each automatic developing machine of Invention Example 1.2 and Comparative Example 2,
As Comparative Example 3, five types of photosensitive materials (Fuji Color Paper Type 2A) was treated and dried, and its properties were investigated.

As a result, in the automatic processors of the inventions 1 and 2, there was no occurrence of deformation, deterioration or reticulation of the five types of photosensitive materials, and the properties of their emulsion surfaces were uniform. This is thought to be due to the ON/OFF control of the four heat generating sources depending on the degree of wetting of the photosensitive material.

On the other hand, in the automatic processors of Comparative Examples 2 and 3, the properties of the five types of photosensitive materials were non-uniform. In other words, the photosensitive material with the highest degree of wetting is not sufficiently dried and the emulsion surface is half-dry, while the photosensitive material with the lowest degree of wetting is overheated. Deformation and alteration had occurred.

<Effects of the Invention> As described above, according to the drying method of the present invention, the drying time is shortened by improving the drying efficiency, and the occurrence of film quality defects such as reticulation on the emulsion surface of the photosensitive material is prevented. can do.

Furthermore, even if conditions such as drying conditions, environmental conditions, and the type of photosensitive material change, the quality of the photosensitive material after drying, especially the properties of the emulsion surface, can be maintained uniform.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view schematically showing an example of the configuration of a drying apparatus used for carrying out the drying method of the present invention. FIG. 2 is a graph showing the surface temperature of the photosensitive material at various locations along the conveyance path of the photosensitive material. FIG. 3 is a cross-sectional front view schematically showing the configuration of a conventional drying device. FIG. 4 is a cross-sectional front view schematically showing the configuration of a drying device of a comparative example. Explanation of symbols l... Drying device 2... Casing 21... Population 22... Outlet 23... Partition wall 24... Passing port 25... Insulating material 3... Drying chamber 4...・Transportation means 41.42.43. 5...Far infrared heater 51.52.53.54...Heating source 6a-6h...Temperature sensor 7...Control means 81.82.83. 84...Relay switch 44...Conveyance roller 10a...Conventional drying device tab...Drying device 11 of comparative example...First drying chamber 12...Second drying chamber 13...No. 3 Drying chamber 14... Partition wall 15... Dryer 150... Duct 151... Opening 152... Heater 16.17... Conveyance roller S... Photosensitive material Sa... Emulsion surface sb.・・Back side FIG, 1 FIG, 2 6a 6b 6c 6d 6e
6f 6g 6h (temperature sensor No.) 51
52 53 54
(Voice - 40) Measurement FIG, 3 Procedure Neho Seisho Ei) January 20, 1989 Patent Application No. 311589 of 1988 2゜Name of the invention Drying method 3゜Relationship with the person making the amendment Patent applicant name Fuji Photo Film Co., Ltd. 4, agent Tenjin Yasaka Kosan Building 3rd floor FIG. 4

Claims (1)

[Claims] (1) While transporting the wet photosensitive material in the drying room,
A drying method for rapidly heating and drying a photosensitive material,
A drying method characterized in that heating is stopped before the water content of the emulsion layer of the light-sensitive material reaches equilibrium.