JPH0720570B2 - Web drying controller in dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a dryer drying controller. More specifically, the present invention relates to a control device that measures the surface temperature of a traveling web in a dryer and the temperature and humidity of hot air to control the dry state of the web.

(B) Conventional Technology A conventional dryer is used for drying a coating liquid applied to a web, for drying a wet or water-containing web, and for heat-treating the web.

When applying the coating liquid to the web with a coater and drying with hot air with a dryer, if the temperature of the hot air is high and the amount of hot air is large, the running web will finish drying in the first half of the dryer and over dry in the latter half of the dryer, and the water content of the coating layer Rate decreases, cracks occur, and the opposite side of the coated surface shrinks due to heat. In particular, when the surface of the web is made of a thermoplastic resin, the surface is melted by excessive heating and an inconvenient gloss is generated. On the contrary, when the drying temperature is low or the amount of hot air is small, the undried web comes out of the dryer and the rolls after the dryer are soiled with the coating liquid. In order to eliminate such a state, conventionally used means for controlling the dry state of the web is to sample the sample from the upper winding part of the roll after being taken out from the dryer and wound, for example, the coating amount of the web, coating. Evaluate the surface quality, gloss, moisture content, surface resistance, etc. to determine the set values such as the drying temperature, humidity and air volume of the dryer during operation, and optimize each set value to achieve the drying conditions that match the target quality. It has become. As a concrete means, based on the data obtained from the experiment, set the coating speed, the drying condition according to the coating amount, for example, the steam valve of the heater, the rotation speed of the hot air supply fan, the damper opening, etc. After drying, the quality of the web is checked and adjusted. If the quality is unfavorable, the condition setting is changed again based on the past data. Further, in order to manage the state of the web as much as possible in real time than the above means, an electromagnetic radiation thickness measuring device such as a β-ray basis weight meter is provided at the dryer outlet, a hot air temperature detector is provided, and the output is output.
I am doing monitoring work. With such a method, it is difficult to always stably manufacture a product that meets the required quality.

(C) Problems to be Solved by the Invention However, in the above-mentioned means, the temperature of the web in the dryer is not known, and it is necessary to change the speed of the traveling web, or when the dryer is wound with different water contents. ,
When the coating amount is changed midway, the quality of the dried web varies depending on the water content of the web before drying, and if the setting change is delayed, a poor quality web will occur.

The problem to be solved by the present invention is to dry the web so that a constant quality web can be obtained after drying even if the web condition before drying such as the running speed of the web, the moisture content of the web before drying or the coating amount changes. It is to provide a dryer control device for controlling.

(D) Means for Solving the Problems In order to solve the above-mentioned problems, it was possible to achieve by the following configurations.

That is, the present invention provides a dryer hood (1) for giving hot air to a running web (2), a plurality of nozzles (3) for blowing hot air to the web (2), and an infrared radiation thermometer (for measuring web surface temperature). 8) a dryer section, a heater (4) for supplying hot air to the dryer section, a hot air supply fan (5), an outside air intake damper (6), a recovered hot air discharge damper (6b), and each connection And a hot air supply unit having a heat supply adjustment power unit (4a), a hot air supply fan drive unit (5a), an outside air intake damper opening adjustment power unit (6a), and a recovered hot air discharge damper opening adjustment power unit (6C). A hot air supply duct (7a) having a supply hot air temperature / humidity detector (9a) connecting the dryer section and the hot air supply unit and a hot air recovery duct (7b) having a recovered hot air temperature / humidity detector (9b), and controlling And the control unit is Infrared radiation temperature measuring device for measuring a the web surface temperature Supplier (8), the supply, the temperature of the recovered hot air, temperature and humidity detector for detecting the humidity (9a, 9
b), a converter A (10) for converting each analog signal detected by the infrared radiation temperature measuring device (8) and the temperature / humidity detector (9a, 9b) into a digital signal, and the digital signal is input and dried. An arithmetic unit (11) for performing a control arithmetic operation and a digital signal output from the arithmetic unit (11) are input to the hot air supply unit to increase or decrease the heating temperature, the amount of hot air, the outside air intake damper (6), and the recovered hot air. The variable amount of the opening of the exhaust damper (6b) is adjusted to the hot air supply adjustment power unit (4a),
The hot air supply fan drive unit (5a), the outside air intake damper opening adjustment power unit (6a), and the recovered hot air discharge damper opening adjustment power unit (6C) have a converter B (12) for outputting. It is a web drying control device in the dryer.

The dryer hood 1 according to the present invention may have a mechanism that opens and closes both vertically and vertically with respect to the web 2, or may have a mechanism that opens and closes a side surface in a door manner.

In the present invention, the nozzles 3 can be arranged in a dryer on both sides of the web 2 with the web 2 sandwiched therebetween. The arrangement is considered together with the number of nozzles according to the purpose.

In addition, the plurality of nozzles 3 are divided into sections, and the hot air supply ducts 7a are divided into sections so that hot air of different temperature, humidity, and air volume can be supplied in one dryer hood 1 into dampers for each hot air supply duct 7a. May be provided to control the drying.

The shape of the nozzle 3 may be designed according to the purpose in consideration of the relationship between the angle at which the hot air is blown from the tip of the nozzle 3 to the web 2, the air volume, and the wind speed. Further, a mechanism for adjusting the distance between the tip of the web 2 and the tip of the nozzle 3 depending on the hot air volume can be attached to the nozzle 3.

The support mechanism for the traveling web 2 in the dryer may support the hot air blown from the upper nozzle 3 by a roll on the lower side of the web 2 or the nozzle 3 on the lower side as well as the upper side.
Alternatively, hot air may be blown from the air to float and support it. If the total length of the dryer is short and the web 2 is tough, the roll at the entrance and exit of the dryer may support it with a slightly high tension, and the inside of the dryer may be unsupported.

The hot air supply unit according to the present invention includes a heater 4 having a built-in heat source unit for radiating heat medium such as steam, electric heat, and heating oil with the radiation fins 4b, a hot air supply fan 5 such as a turbo fan, a box blower, and a high humidity. Collected hot air exhaust damper 6b for discharging collected hot air and taking in outside air to lower the dew point temperature
And an outside air intake damper 6, and a mechanism and a drive unit for adjusting the heat medium supply amount, the fan air flow amount, the damper opening degree, etc., for example, a diaphragm control valve, a solenoid valve, a piston control valve, a stepping motor, an inverter motor, a heater,
It consists of a transformer.

A humidifier may be built in the heater 4 so that the dew point temperature of hot air can be corrected. Further, the dryers may be divided into sections, and a plurality of heat supply units may be provided so that hot air having different temperatures, humidity and air volumes can be supplied in one dryer hood 1.

Supply / recovery hot air temperature / humidity detectors 9a, 9b in the present invention
Since the purpose is to detect the temperature and humidity of the hot air before and after drying, the hot air just before being blown onto the web 2 and the hot air just after being used for drying are detected by the detector installed in the dryer hood 1. It goes without saying that it is ideal to make holes in the wall of the duct 7a that supplies hot air to the nozzles 3 that are substantially the same, and in the wall of the duct 7b that returns from the dryer hood 1, respectively. The detection sensor can be inserted and fixed to take out an analog signal. Although the present invention uses humidity, dew point temperature may be used instead.

The infrared radiation temperature measuring device 8 according to the present invention will be described with reference to FIG. 3. The infrared radiation radiated from the web 2 is received by the sensor portion 13 and the intensity thereof is output as an analog signal to determine the surface temperature of the web 2. It corresponds. The optical path is covered by a cylindrical optical path cover 14 so that the disturbance radiation infrared ray does not enter the infrared ray receiving sensor section 13, and only the infrared ray radiating from the web surface is received by the infrared ray receiving sensor section 13
Is incident on. The infrared light receiving sensor portion 13 itself is also covered by the sensor portion cover 16 except for the infrared incident window 15, and the sensor portion cover 16 is integrated with the cylindrical optical path cover 14. The cylindrical optical path cover 14 is inserted into the wall of the dryer hood 1 up to 1 cm to 5 cm directly above the web, and the whole is fixed to the wall of the dryer hood 1 with a fixing base 17. In addition, the purge air blow-in port is installed inside the sensor cover 16.
Cooling air is blown in from 18 and is purged from inside the sensor cover 16 through the optical path cover 14 so as not to be affected by the surface temperature of the web 2 to prevent overheating of the sensor due to hot air from the dryer. There is. As for the positional relationship between the infrared radiation temperature measuring device 8 and the dryer hood 1, the entire infrared radiation measuring device including the cover for covering the sensor part may be inside the dryer hood 1 as long as the sensor part does not overheat. When a plurality of nozzles 3 in the dryer hood 1 are lined up, a cylindrical cover is inserted between the nozzles 3 to measure the surface temperature of the web 2. A plurality of infrared radiation temperature measuring devices 8 may be installed anywhere in the dryer hood 1 and a plurality of infrared radiation temperature measuring devices 8 may be installed.

The converter A10 in the present invention is a multi-channel A / D converter according to the number of sensors. The computing unit 11 uses a microcomputer. It is more preferable to connect the storage device 11a as a data box to the arithmetic unit 11. Converter B
12 receives the digital signal from the computing unit 11 and changes the amount of hot air and the superheat temperature for driving each power unit of the hot air supply unit, and the variation of the opening degree of the outside air intake damper 6 and the recovered hot air discharge damper 6b. It is an output gate that outputs. Also, the converter A1
Even if 0, the arithmetic unit 11, the storage device 11a, and the converter B12 are all integrated and centrally controlled as long as they have the functions described in the present invention, this does not apply.

The method of controlling the web drying control device in the dryer according to the present invention is such that when hot air is blown onto the web 2 running in the dryer, volatile matter such as water content absorbs latent heat from the web 2 and evaporates. Depending on the size, and the size of the accumulation of sensible heat of the web 2 when heated simply,
Since the surface temperature of the web 2 changes, the amount of hot air blown onto the traveling web 2 so that the surface temperature is always constant,
By increasing or decreasing the amount of change in temperature and humidity, control is performed so that a constant quality is obtained.

Explaining the mutual relation of each component in the drying control concretely, the surface temperature of the web 2 is measured by the infrared radiation temperature measuring device 8 and the temperature and the humidity of the hot air supplied to the dryer nozzle 3 are detected. The temperature and humidity of the hot air detected by the container 9a and collected from the dryer hood 1 are detected by the collected hot air temperature / humidity detector 9b. The detected analog signals are converted into digital signals by the converter A10 and input to the arithmetic unit 11. With the calculator 11, the target surface temperature of the web 2, the upper and lower limit temperatures of the hot air, the humidity,
And the set value of the air volume, and the arithmetic expression indicating the relationship between the input signal and the set value are input. In the calculator 11, the value of the surface temperature of the web 2 measured by the infrared radiation temperature measuring device 8 and the set value are compared and calculated, and when the web surface temperature is higher than the set value, the heat supply and the hot air supply amount of the heater 4 Is output from the arithmetic unit 11, is input to the converter B12, from the converter B12 to each heat supply adjustment power unit 4a and the hot air supply fan drive unit 5a variable amount is output to reduce the amount of power. It For example, when the heat supply is steam, the steam valve opening is closed, and when the fan drive unit is an inverter motor, the rotation speed is decreased. The calculated result,
On the contrary, when the web surface temperature is lower than the set value, the signal for increasing the hot air supply and the hot air supply amount of the heater 4 is calculated by the calculator.
11 output, input to converter B12, and further converter B12
From the heat supply adjustment power unit 4a and the hot air supply fan drive unit
The variable of power increase is output to 5a, the temperature and volume of hot air increase, drying is promoted, the surface temperature of the web 2 rises, and approaches the set value. A signal is distributed to the ratio of the variation amounts to the hot air supply adjusting power unit 4a and the hot air supply fan driving unit 5a output from the converter B12 by the arithmetic expression previously input to the arithmetic unit 11.

In addition, the upper and lower limits of the temperature of the hot air must be set as a condition so that the fluctuation range of the temperature of the hot air does not heat up or drop extremely.
It is set and input to 11, and is checked by the hot air temperature / humidity detector 9a for supply, and when the adjusted temperature is in a state requiring a temperature outside the upper and lower limits, it is adjusted by the air volume.

As for humidity, since hot air circulates, it must be controlled so that hot air with a constant humidity is supplied because the humidity increases.

That is, the relative humidity of hot air is set in advance.

The signal converted by the converter A10 from the supply / recovery hot air temperature / humidity detector 9b and input to the calculator 11 is the calculator 11
In the above, the value is calculated by comparison with a preset relative humidity value, and when the humidity of the hot air is higher than the setting, a signal for increasing the opening degree of the outside air intake damper is output from the calculator 11 and input to the converter B12. Further, a variable amount is output from the converter B12 to the outside air intake damper opening adjustment power unit 6a to take in fresh air. In proportion to the opening of the outside air intake damper 6, a variable that increases the opening is also output to the recovery hot air exhaust damper opening adjustment power unit 6c, and the opening of the recovery hot air exhaust damper 6b increases, resulting in a change in humidity. Low hot air is supplied to the nozzle 3.

If the humidity of the hot air is lower than the set value, the opening of the outside air intake damper 6 will be reduced to suppress the intake of fresh air, and the signal from the calculator 11 will also proportionally reduce the opening of the collected hot air exhaust damper 6b. It is output to the converter B12, and the variable amount is further output from the converter B12 to the recovered hot air exhaust damper opening adjustment power unit 6c. Also, the upper and lower limits of humidity are set and input to the calculator 11 so that extreme humidification and dehumidification do not occur, and the comparison between the two is calculated so that the difference in humidity between the supply side and the recovery side maintains a steady state. It is incorporated into and is proportionally controlled.

The web 2 in the present invention may be of any type as long as it is a strip-shaped sheet. Further, the web 2 is intended not only for drying but also for heat treatment using the control device of the present invention. Particularly preferably, paper in the coating drying step, laminated paper,
Films, non-woven fabrics, cloths, metal sheets, etc. are listed.
In addition, examples include impregnated paper, non-woven fabric, film, web-like mesh in the heat treatment step.

The present invention is suitable as a drying control device for a photographic support coated with a coating liquid.

That is, by controlling the rising temperature of the photographic support during the drying process of the photographic support which requires precise drying conditions, troubles as the photographic support can be minimized. For example, fogging after the photographic printing paper becomes a photographic printing paper due to a decrease in water content of the photographic support, curling due to overdrying when the gelatin composition solution is applied and dried, abnormalities in the gelatin composition coating layer due to rapid drying. It is possible to suppress or ameliorate glossiness, similarly decrease in film strength of the coating layer, stickiness due to insufficient drying, insufficient adhesion of emulsion film after coating of photographic emulsion, and the like.

Further, the present invention is effective for suppressing the melting of the fine mold for the glossy glare caused by the heating and melting of the resin layer for the web having the thermoplastic resin coating layer, and the fine mold for the surface roughening treatment.
Taking the above photographic support into consideration, it is a particularly suitable drying control device for undercoating or back-coating a polyolefin resin-coated photographic support with a gelatin composition solution or a synthetic binder composition solution. .

(E) Action The action will be described with reference to FIG. FIG. 2 shows a block diagram of the control signal of the present invention. First, the surface temperature of the web 2, the temperature of the upper and lower limits of the supplied hot air, the humidity, and the air volume are preset in the storage device 11a or the computing unit 11, and the drying of the running web 2 is started. The surface temperature of the traveling web 2 inside the dryer is measured by the infrared radiation temperature measuring device 8, the temperature and humidity of the hot air supplied to the dryer nozzle 3 are detected by the supplied hot air temperature humidity detector 9a, and the hot air collected from the dryer hood 1 is detected. The temperature and humidity of the temperature are detected by the recovered hot air temperature and humidity detector 9b. The detected analog signals are input to the arithmetic unit 11 converted into digital signals by the converter A10. A calculator 11 to which a digital signal is input
, The difference between the web surface temperature and a preset temperature is calculated, and an output digital signal for increasing / decreasing the air volume and / or the heating temperature corresponding to the difference is sent to the converter B12, and the converter receiving the signal A variable amount is output from B12 to the heat supply adjustment power unit 4a and / or the hot air supply fan drive unit 5a for adjusting the heat supply amount of the heater 4.

For the distribution of the outputs of the heat supply adjusting power unit 4a and the heat supply fan drive unit 5a, an arithmetic expression is input to the arithmetic unit 11 in advance. In addition, the upper and lower limit temperatures are set in the calculator 11 to prevent excessive heat or low temperature.
The signal detected by the supply hot air temperature / humidity detector 9a passes through the converter A10 and is input to the calculator 11,
It is compared with the set value and checked. Since the upper and lower limits of the heating temperature are set, if the heating temperature cannot control, the amount of air flow is increased or decreased by that amount.

The temperature and humidity of the hot air are calculated by calculating the difference between the supplied hot air temperature / humidity detector 9a and the recovered hot air temperature / humidity detector 9b, and the difference between the set value and the supplied hot air temperature / humidity detector 9a. The signal for raising the temperature to be generated by the heater 4 is the calculator 11
Is output to the converter B12, and the converter B12 outputs a variable amount for increasing the amount of steam to the heat supply control power unit 4a that drives the steam valve of the heater 4. In addition, in response to the increase in hot air humidity due to evaporation from the web 2, the digital signal is output from the calculator 11 to the converter B12, and the converter B12
As a result, a variable amount for increasing and adjusting the damper opening is output to the outside air intake damper opening adjusting power unit 6a to take in fresh air.

Also, if necessary, a signal for adjusting the opening of the collected hot air exhaust damper 6b to discharge the collected hot air in proportion to the opening of the outside air intake damper 6 according to the introduction of fresh air is also output to the converter B12 at the same time. Then, the converter B12 outputs a variable amount for increasing and adjusting the damper opening degree to the recovered hot air exhaust damper opening degree adjusting power unit 6c.

The temperature drop of the hot air due to the intake of fresh air is detected by the hot air temperature / humidity detector 9a or the infrared radiation temperature measuring device 8 and the value to be raised by the heater 4 is calculated by the calculator 11 via the converter A10. Output to converter B12.

(F) Embodiment An embodiment of the present invention will be described with reference to FIG. 1 corresponding to the embodiment.

A dryer hood 1, a web 2 running inside the dryer hood, and a dryer unit having a nozzle 3 for blowing hot air, a heater 4 for supplying hot air to the nozzle, radiation fins 4b for increasing heat radiation efficiency inside the heater, hot air The supply fan 5, the outside air intake damper 6, the recovered hot air exhaust damper 6b, and the power unit connected to each, that is, the heat supply adjustment power unit 4a, the hot air supply fan drive unit 5a, and the outside air intake damper opening degree adjustment power unit. 6a, a hot air supply unit including a recovery hot air discharge damper opening adjustment power unit 6c, and a hot air supply duct 7 that is connected to the nozzle 3 of the dryer unit and the hot air supply unit to supply hot air to the nozzle 3.
a, a hot air collecting duct 7b for connecting the dryer hood 1 and the hot air supply unit to collect hot air, and a control unit, and the control unit measures infrared radiation temperature for measuring the surface temperature of the web 2 running in the dryer. Device 8, temperature and humidity detectors 9a and 9b for detecting the temperature and humidity of each of the supplied hot air and the recovered hot air, and further the infrared radiation temperature measuring device 8 and the supplied hot air temperature and humidity detector
Converter A1 that inputs the analog signal of 9a and the recovered hot air temperature and humidity detector 9b and outputs the digital signal
0, a computing unit 11 that receives the digital signal and performs computation or control, and an output output from the computing unit 11 that controls the heating of the heater 4 of the hot-air supply unit by a heat-supply adjusting power unit 4a and a hot-air supply fan Hot air supply fan drive unit 5a for adjusting the air volume of 5, external air intake damper opening adjustment power unit 6a for adjusting the opening degree of the external air intake damper 6, and recovered hot air exhaust for adjusting the opening degree of the recovered hot air exhaust damper 6b This is a drying control device that can control the drying of the traveling web 2 in the dryer by having the converter B12 that outputs a variable for opening and closing each damper in the damper opening adjustment power unit 6c.

Further, depending on the brand, the type of coating liquid, etc., each set value is input to the storage device 11a, and the drying of the traveling web 2 in the dryer can be controlled only by specifying the brand, the type of coating liquid, etc.

When drying a polyethylene resin-coated photographic support coated with a coating liquid consisting of gelatin, pigment, hardener, and surfactant as the web 2, the inside temperature of the photographic support was adjusted to 68 ± 2 ° C. The temperature detected by the infrared radiation thermometer 8 is determined so that the hot air flow rate from the nozzle 3 in the dryer is 10 m / sec.
Set the amount corresponding to ~ 12m / sec, the upper limit temperature of the supplied hot air is 100 ℃, the lower limit temperature is 60 ℃, the relative humidity is upper limit 70RH%, the lower limit 5
It was set to 0 RH% and dried.

As a result, the surface temperature of the paper was in the range of 68 ± 2 ° C., and the drying was able to be controlled without increasing the gloss and decreasing the water content of the base paper due to melting of the polyethylene-coated resin, and without causing insufficient drying.

(G) Effect of the Invention In the present invention, the controller controls the infrared radiation temperature measuring device for measuring the surface temperature of the web inside the dryer, the temperature and humidity detector for detecting the temperature and humidity of the hot air supplied and recovered, the infrared radiation temperature measuring device and temperature. A converter A that converts each analog signal detected by the humidity detector into a digital signal, a calculator that receives the digital signal and performs a drying control calculation,
And a converter B which inputs the output from the arithmetic unit and outputs to the hot air supply unit a change in the amount of hot air and the heating temperature, and a variable amount of opening of the outside air intake damper 6 and the recovered hot air exhaust damper 6b. Since it is a web drying control device inside the dryer, when the moisture content of the web inside the dryer changes, the infrared radiation temperature measuring instrument, the analog signal of the hot air temperature detector changes, and the calculator calculates and compares it with the set value. In order to eliminate the deviation from the setting, a hot air supply fan,
By appropriately changing the heater and the damper, the running web does not come out of the dryer due to undried or overdried, a web in a constant dry state is obtained, and the drying is controlled.

In particular, as described in the examples, it is found that it is suitable for a web drying control device in a dryer of a photographic support coated with a polyolefin resin.

[Brief description of drawings]

FIG. 1 shows a schematic diagram for explaining an embodiment of the present invention. Second
The figure shows the relationship between the control system flow of the drying controller and the drive unit to be controlled. FIG. 3 shows the positional relationship between the infrared radiation thermometer and the dryer hood. Among them, (3-1) is an elevation view of WZ cross section as seen from the flow direction of the web, and (3-2) is X-axis.
It is a top view of a -Y cross section. 1 ... dryer hood, 2 ... web, 3 ... nozzle, 4 ...
Heater, 4a ... Heat supply adjusting power unit, 4b ... Radiating fins, 5 ...
Hot air supply fan, 5a ... Hot air supply fan drive unit, 6 ... Outside air intake damper, 6a ... Outside air intake damper opening adjustment power unit,
6b ... Recovered hot air exhaust damper, 6c ... Recovered hot air exhaust damper opening adjustment power unit, 7a ... Hot air supply duct, 7b ... Hot air recovery duct, 8 ... Infrared radiation temperature measuring device, 9a ... Supplied hot air temperature / humidity detector, 9b ... Recovered hot air temperature / humidity detector, 10 ... Converter A, 11 ... Arithmetic unit, 11a ... Storage device, 12 ... Converter B, 13 ...
Infrared light receiving sensor section, 14 ... Optical path cover, 15 ... Infrared incident window, 16 ... Sensor section cover, 17 ... Fixing base, 18 ... Purge air blowing port

Claims (3)

[Claims] 1. A dryer hood (1) for giving hot air to a running web (2), a plurality of nozzles (3) for blowing hot air to the web (2), and an infrared radiation thermometer (8) for measuring the web surface temperature. ), A heater (4), a hot air supply fan (5), an outside air intake damper (6), a recovered hot air discharge damper (6b), and a heater (4) for supplying hot air to the dryer unit. A hot air supply unit having a heat supply adjustment power unit (4a), a hot air supply fan drive unit (5a), an outside air intake damper opening adjustment power unit (6a), and a recovered hot air discharge damper opening adjustment power unit (6C), A hot air supply duct (7a) having a supply hot air temperature / humidity detector (9a) and a hot air recovery duct (7b) having a recovered hot air temperature / humidity detector (9b), which connects the dryer unit and the hot air supply unit, and a control unit. And the control unit is Infrared radiation temperature measuring device (8) for measuring the surface temperature of the web in the ear, temperature and humidity detectors (9a, 9b) for detecting the temperature and humidity of the supply and recovery hot air, the infrared radiation temperature measuring device (8) and temperature and humidity A converter A (10) for converting each analog signal detected by the detectors (9a, 9b) into a digital signal, a calculator (11) for receiving the digital signal and performing a drying control calculation, and the calculator (1)
The digital signal output from 1) is input to the hot air supply unit to increase or decrease the heating temperature, the amount of hot air, and the open air intake damper (6) or the recovered hot air exhaust damper (6b) opening degree variation. Adjustment power unit (4a), hot air supply fan drive unit (5a), outside air intake damper opening adjustment power unit (6a),
A web drying control device in a dryer, which has a converter B (12) for outputting to a power unit (6C) for adjusting the opening degree of the recovered hot air exhaust damper. 2. A dryer web drying control device according to claim 1, wherein said web (2) is a web (2) having a thermoplastic resin layer. 3. The web drying control device in a dryer according to claim 1, wherein the web (2) is a photographic support.