JPS6076759A - Dew condensation preventive device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To prevent surely condensation in a copying machine with low electric power consumption by detecting external humidity in addition to the internal and external temps. of the copying machine, and controlling automatically the operation of a heater for preventing condensation from the values of said temps. and humidity. CONSTITUTION:An internal temp. t1 and external temp. t2 are detected by an internal temp. sensor 1 and an external temp. sensor 2 for a copying machine and the humidity h2 at the temp. t2 is determined by a curve S2 passing through the point C of 100% humidity under the satd. steam pessure S2 at the temp. t1. On the other hand, the actual external humidity (h) of the copying mahcine is measured by a sensor 3 for detecting the external humidity of the copying machine and the humidities (h) and h2 are compared by a comparator 4. A heater 6 for preventing condensation installed in the copying machine is operated by a control device 5 when h>=h2 or h-h2>=c (c is a constant), by which the condensation in the copying machine is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dew condensation prevention device after electronic copying, and more specifically, to a device for preventing dew condensation after electronic copying. The present invention relates to a dew condensation prevention device that operates a dew condensation prevention heater installed in the copying machine to prevent dew condensation inside the copying machine.

In prior art electronic copying machines, copying troubles occur in the optical system including lenses and mirrors, photosensitive drums, etc. in the copy mode due to the problem 16. Condensation occurs when room temperature rises rapidly due to combustion type heaters such as kerosene heaters, and is particularly likely to occur immediately after heating starts in winter. In such a case, the air around the simulator is rapidly heated by the heater, and the humidity in the room is crystallized by the water produced by the combustion of oil, etc.; The elevated air enters the copier and contacts parts within the copier that are still at a significantly lower temperature than the air, causing condensation to form on the parts. In order to prevent such condensation on the parts inside the copying machine, a heater for preventing condensation is usually placed inside the copying machine. Starts energizing the heater when the main switch that operates the machine is turned off;
■Methods such as installing a thermistor inside the copying machine and energizing the heater when the internal temperature falls below a certain temperature have been adopted. However, with these methods, the heater is energized for a very long time in any case, and the heater is energized even when the copying machine is not used for a long time, especially on holidays, resulting in unnecessary power consumption. Therefore, in order to prevent this, the operator had to manage the on/off operation of the heater switch as appropriate depending on the situation.

Purpose of the Invention The present invention aims to prevent dew condensation by focusing on the fact that condensation tends to occur when there is a difference in temperature and humidity inside and outside an electronic copying machine. It is an object of the present invention to provide a dew condensation prevention device that eliminates the above-mentioned drawbacks of conventional dew condensation prevention devices in copying machines and that allows dew condensation to occur reliably within the copying machine with low power consumption.

Structure of the Invention The above-mentioned object of the present invention is to detect the outside temperature, inside temperature, and outside humidity of an electronic copying machine, and to adjust the outside humidity to a humidity corresponding to a saturated vapor pressure value or a vapor pressure value close to the saturated vapor pressure value at the inside temperature of the machine. This is achieved by a dew condensation prevention device that specifically activates the dew condensation prevention heater in the copying machine when the dew condensation prevention device reaches the limit.

The present invention will be explained in more detail below. The first graph 1 is a graph showing the relationship between @ degrees and saturated water vapor pressure, which is 76 αnHg at a temperature of 100° C. in the atmosphere (1 atm).

Based on this graph, if we calculate the relationship between temperature and humidity (relative humidity) by taking the vapor pressure as a parameter, we obtain Figure 2. That is, point A in FIG. 2 corresponds to point A in FIG. Point B in Figure 2 is ("X 100) in Figure 1.
2 and corresponds to point B in FIG. tl of figure 1 below
If the same operation is performed for any t between , and tl, the curve S1 in FIG. 2 will be rejected. The curves S2+ S'2 r S//2, etc. in FIG. To explain the present invention with reference to FIG. 2, when the environment outside the electronic copying machine is stable and the conditions inside the copying machine are the same as the environmental conditions, the temperature is tl, and the humidity is h.
l, water vapor pressure is 81. The temperature inside the copier is now 1. When the humidity decreases from t'1 to t'1, the humidity moves along the curve S and reaches point A, where it becomes 100% and condensation occurs.

The trench is heated and the outside temperature rises from tl to t2,
The amount of water vapor in the air also increases, the humidity reaches h2, and the water vapor pressure of the atmosphere at that time is 82. When this atmosphere is cooled from temperature t2 to tl while maintaining the water vapor pressure $2, the humidity increases along curve S2 and reaches the 0 point, becoming 100%. By the way, if the humidity in the atmosphere is h'f when the atmosphere is 12iii1ijz, the water vapor pressure of the atmosphere at that time is B/, and when the atmospheric temperature drops from t2 to 11, the humidity increases according to the curve 3/2. However, warm 1tt1
The humidity will not be 100%. Also, if the humidity is h"2 when the atmospheric flow rate is 11, then when the atmospheric temperature drops from t2 to tl, the humidity becomes 1llIS2"? Old and growing,
Before the temperature reaches t1, the humidity becomes 1fioo% and condensation occurs. To summarize the above, it is as follows: Temperature inside the copying machine! <When the temperature outside the copying machine is t2, if the humidity outside the copying machine h ('bt')<ht, no condensation occurs.Humidity outside the copying machine h (= h X) > h
If it is 2, condensation will occur.

FIG. 3 shows a control mechanism of a heater for preventing dew condensation according to the present invention. According to the present invention, the internal temperature (tl) and the external temperature (t2) are detected by the copying machine internal temperature detection sensor 1 and the copying machine external temperature detection sensor 2, and the humidity of 100% of the saturated vapor pressure S2 at the temperature t1 is 0. The humidity (h2) at temperature t2 is determined by a curve S passing through the point (see Figure 2). On the other hand, the humidity detection sensor 6 outside the copying machine
The actual humidity (hl) outside the copying machine is measured, and the comparator 4
Compare h and h2 by, h≧h2 or h−h2≧
C (C is a constant), the control device 5 activates the condensation prevention heater 6 installed in the copying machine,
Prevents condensation from forming inside the copier. The reason why the above h−h2 was not set to zero but was set to a constant C was because the degree of failure of the temperature C% was set in order to completely prevent the occurrence of dew condensation.
%.

As explained above, according to the present invention, the delivery prevention heater inside the copying machine can be activated quickly and accurately based on the temperature inside and outside the copying machine and the atmospheric humidity in the place where the copying machine is installed. When the temperature inside the gutter reaches the temperature outside the machine, the power supply to the motor is stopped, so the power consumption of the heater can be minimized.

Note that the graphs in Figures 1 and 2 change due to fluctuations in atmospheric pressure, but in general there is no problem in practice even if the atmospheric pressure is 1 atm, and the S curve in Figure 2 is approximately a straight line at a practical temperature of 00 to 40°C. can be approximated to.

Effects of the Invention According to the present invention, the humidity outside the electronic copying machine is detected in addition to the inside temperature and the outside temperature of the electronic copying machine, and these temperature and humidity values are used to prevent condensation inside the electronic photo close-up machine. Since the operation of the prevention heater can be automatically controlled,
Compared to control based only on the temperature inside and outside the copying machine, it is possible to more accurately detect situations where dew condensation is likely to occur inside the copying machine, and to quickly activate the heater to prevent condensation when a situation occurs that requires activation of the condensation prevention heater. When the heater is energized and the temperature inside the machine reaches the temperature outside the machine, the power supply to the heater is stopped, so it is possible to prevent condensation with the minimum necessary energization time and prevent the heater from operating. power consumption can be suppressed to a minimum.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between temperature and saturated water vapor pressure, Fig. 2 is a graph showing the relationship between temperature and humidity with vapor pressure - Lanaucou, and Fig. 6 is a graph showing the relationship between temperature and humidity based on the vapor pressure. FIG. 3 is a diagram for explaining a control mechanism. Codes in the figure: 1...Temperature detection sensor inside the copying machine, 2...
Temperature detection sensor outside the copying machine, 6... Humidity detection sensor outside the copying machine, 4... Comparator, 5... Control device, 6...
- Heater to prevent condensation.

Claims (1)

[Claims] Detects the internal temperature, external temperature, and external temperature of the electronic copying machine, and prevents condensation inside the copying machine when the external humidity reaches the saturated vapor pressure value at the machine internal temperature or the humidity corresponding to the vapor pressure value close to it. A dew condensation prevention device for an electrophotographic copying machine, which operates a heater for use in electrophotographic copying machines.