JPS61110137A - Heater for processing solution - Google Patents

Abstract

PURPOSE:To eliminate the need for a liquid level sensor, and to reduce the cost and to facilitate the fittinb by installing a heater and a temperature sensor in the same protection body closely to each other, and detecting a liquid level from temperature variation when the heater is turned on or off. CONSTITUTION:The temperature detecting resistor 18 and heater 20 are embed ded in the protection body 16 made of ceramic closely to each other to consti tute a processing solution heater 14. The output of a heater power circuit 24 is turned on to heata developer 12 by the heater 20 for a specific time, and the temperature of the developer 12 is detected by the temperature detecting resistor 18. This temperature detecting resistor 18 constitutes a bridge circuit 30, the unbalanced voltage of which is inputted to an A/D converter 32, whose output is inputted to a microcomputer 28. Namely, when the rise time in a heater-on state or fall time in a heater-off state is larger than a specific value, it is decided that the liquid level is abnormal. Consequently, a liquid level sensor needs not be provided specially, the cost is reduced, and the fitting and wiring are facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a processing liquid heating heater that not only heats the processing liquid but also can detect the temperature of the processing liquid and furthermore detect the liquid level.

[Conventional technology]

For example, the optimum temperature for a color film developer is between 37 degrees and 3 degrees.
The liquid temperature is detected by a temperature sensor, and the developer is heated appropriately by a heater to maintain the liquid temperature at an appropriate temperature.

Further, the level of the developer in the processing tank decreases due to adhesion of the developer to the film, evaporation, drainage, etc. Therefore, the liquid level of the developer is detected by a liquid level sensor, and in the event of an abnormality, an alarm is issued or a pump is used to supplement the developer to keep the liquid level constant.

[Problem that the invention seeks to solve]

However, since the temperature sensor, liquid level sensor, and heater are provided separately, the cost is high and the installation to the processing tank and wiring are complicated.

[Means for solving problems]

In order to solve the above problems, the processing liquid heating heater according to the present invention has a heater and a temperature sensor housed close to the protector, and a liquid that detects the liquid level from the temperature change when the heater is turned on or off. It has level discrimination means.

[For production]

A temperature sensor detects the temperature of the processing liquid, and if the temperature falls below the appropriate temperature, the heater is turned on and off to heat the processing liquid and maintain it at an appropriate temperature.

If the rise time when the heater is on is less than a certain value or the fall time when the heater is off is more than a certain value, it is determined that the liquid level is abnormal. This rise time or fall time may be measured indirectly. For example, a drop in the liquid level may be determined from the temperature or temperature change rate when a certain period of time has passed after the heater is turned on or off.

〔Example〕

An embodiment in which a processing liquid warming heater according to the present invention is used in a developing device will be described with reference to the drawings.

As shown in FIG. 2, a developer tank 10 contains a developer 12, in which a film (not shown) is immersed for development.

A processing liquid heating heater 14 is inserted into the developing tank 10 . This processing liquid heating heater 14 is, as shown in Fig. jI1,
A resistance temperature detector 18 and a heater 2 are mounted on a ceramic protector 16.
0 are buried close together.

In this first embodiment, the temperature measuring resistor 18 is arranged above the heater 20.

The developer in the developer tank 10 is replenished via a pump 22.

Power for the heater 20 and pump 22 is supplied from a heater power supply circuit 24 and a pump power supply circuit 26, respectively. The output voltages of the heater power supply circuit 24 and the pump power supply circuit are switched by a microcomputer 28.

The temperature measuring resistor 18 constitutes a bridge circuit 30, and its unbalanced voltage is input to a λ/D converter 32, converted to a digital signal, and then input to the microcomputer 28. The input voltage of the bridge circuit 30 is supplied from the microcomputer 28.

The microcomputer 28 also receives signals from the liquid level sensors 34 and 36 of the developer 12, and is designed to detect a low level and a high level, respectively.

Next, the operation of the first embodiment configured as described above will be explained in the third embodiment.
The explanation will be given according to the control flowchart shown in the figure.

Read temperature T (step 10.0), T≧37.5℃
If so, the process returns to step 100, and if the temperature is T (37.5° C.), the output of the heater power supply circuit 24 is turned on and the developer 12 is heated by the heater 20 (step 104).

Next, as shown in FIG. 4 (4), after waiting for to (6) to elapse (step 106), the heater power supply circuit 2
4 is turned off (step 108).

Due to this heating to(8), the temperature at the position of the resistance temperature detector 18 rises as shown in FIG. 4(B).

In FIG. 4(B), the solid line shows the temperature change when the liquid level of the developer L2 is higher than the position of the resistance temperature sensor 18 (hereinafter referred to as the full level), and the dashed line shows the temperature change of the developer L2. 12 shows a temperature change when the liquid level is lower than the position of the resistance temperature detector 18 (hereinafter referred to as an empty level). That is, the protector 14 is cooled faster when the level is full than when it is empty (the falling time is shorter).

Next, the temperature T is read and this value is set as T1 (step 110). Next, jlsI! Wait for e to elapse (step 112, see FIG. 4(A)), read the temperature T, and set this value as T (step u4\Then, T
, -T, )K (K is a constant value), that is, the protector 1
If the cooling rate in step 4 is fast, it is determined that the level is full, and tt
Wait until sllc has elapsed (step 118, see Figure 4 (■)), and then return to step 100 at the beginning. T, −T, ≦
In this case, that is, if the cooling rate of the rod protector 16 is slow, it is determined that the level is empty, an alarm (not shown) is turned on, and the developing process is stopped (step 120).

Note that when the liquid level sensor 34 is off and low level force is detected according to a timer interrupt processing routine (not shown), the output of the pump power supply circuit 26 is turned on. When the liquid level sensor 36 detects a high level, the output of the pump power supply circuit 26 is turned off. In this case, the flow rate of the developer to be replenished is small, and if the developer@12 is leaking, the empty level will be detected even if this replenishment is performed. Furthermore, if the pump 22 fails and a long period of time has elapsed, the empty level is also detected.

Next, a second embodiment of the present invention will be described.

In this second embodiment, as shown in FIG. 5, the temperature measuring resistor 18 of the processing liquid heating heater 14 is placed close to the heater 20. Therefore, the speed at which the temperature rises or falls when the heater 20 is on or off differs greatly between the empty level and the full level compared to the first embodiment, and the liquid level can be determined more accurately.

Note that the temperature sensor is not limited to a resistance temperature detector, but may be a thermistor, a thermocouple, or the like.

〔Effect of the invention〕

In the processing liquid heating heater according to the present invention, since the heater and the temperature sensor are housed in the same protector, costs can be reduced, and installation and wiring to the processing tank are simple.

In addition, the temperature sensor is close to the heater and detects the liquid level from the temperature change when the heater is on or off, so there is no need to provide a separate liquid level sensor, further reducing costs. Moreover, it has the excellent effect of being easy to attach to the processing tank and to easily wire.

[Brief explanation of drawings]

Low chart, Figure 4 (person) shows the heater being turned on and off. 14... Processing liquid heating sensor 16... Protector 18... Resistance temperature sensor 20... Heater representative Patent attorney Atsushi Nakajima Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A heater that heats the processing liquid, a temperature sensor that detects the temperature of the processing liquid, a protector that houses the heater and temperature sensor in close proximity, and a liquid level that detects the liquid level from temperature changes when the heater is on or off. A processing liquid heating heater having a determining means.