JPS5817950B2 - Exhaust plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electrophotographic copying apparatus using a liquid development method, in which evaporated carrier liquid from a developing section and a fixing section is collected in the apparatus and recycled to the developing section. This invention relates to a reusable liquid developing copying device.

Conventionally, in liquid development electrophotographic copying devices, charging and
After exposure, the photosensitive material or photoreceptor on which the electrostatic latent image has been formed is introduced into a developer containing petroleum such as Aituba as a carrier liquid and toner dispersed therein, and the photosensitive material is developed using a pair of aperture rollers. Most of the adhering developer is squeezed out by a fixing dryer, and the remaining carrier liquid is evaporated in a fixing dryer to fix the toner.

In the case of a transfer method, the toner image on the photoreceptor is transferred to a transfer material via a carrier liquid, and the remaining carrier liquid is evaporated in a fixing/drying device to fix the toner image.

In this case, the evaporated carrier vapor is generally directly discharged outside the machine and diffused into the room, but since the carrier liquid is a petroleum-based solvent and is not sanitary, even a small amount cannot be ignored.

Particularly when copying machines are used in a closed room, the amount of carrier vapor emitted per unit time tends to increase due to recent high-speed operations, which poses a risk of harm to the health of indoor workers. .

Furthermore, the amount of carrier liquid carried away from the developing device by the photosensitive material or transfer material is minute (0.3 to 1 cc) per sheet.
/A41 sheets) However, if a large number of copies are made, the amount will be considerable and cannot be ignored economically.

In view of the above points, the present invention is devised to circulate and use the carrier vapor without discharging it outside the machine, and in the circulation system, the carrier vapor is condensed to a high concentration and collected and removed from the air. This eliminates hygienic problems, and also allows the recovered carrier liquid to be reused for development, which also has economical features.

The present invention relates to an apparatus that separates a carrier liquid collected and removed from the air from moisture contained in the air and copying materials that are collected at the same time, and circulates only the carrier liquid to a developing tank for reuse.

To explain the embodiment shown in the drawings, in FIG. 1, a photosensitive material on which an electrostatic latent image has been developed with a liquid developer or a transfer material S on which the developed image on a photoreceptor has been transferred is placed in a fixing drying chamber 1. It is introduced from the inlet 2 and delivered to the tray 4 from the outlet 3.

The fixing drying chamber has a structure as airtight as possible, with entrances 2. The outlet 3 is also sealed with sealing rollers 51, 52, 61.6□.

The transfer material S led into the fixing/drying chamber 1 from the entrance 2 advances with its back surface in close contact with a hot plate 7 with a built-in heater, and its front surface is pre-dried by being blown with air from a duct 8. Ru.

Next, a heat roller 9 with a built-in heater and a push roller 10
The carrier liquid is completely evaporated to dry and fix.

A suction port 11 is provided in the rear half of the fixing drying chamber 1, and high temperature air containing carrier vapor is guided into the recovery device 13 provided in a part of the stand 12 of the copying machine. is sucked into the blower 16 via the heat exchanger/condenser 14 and the mist collector 15.

The air blown out from the blower 16 is guided from the duct 17 to the duct 8 through the heat exchanger 14, and is blown out into the fixing drying chamber 1 again, forming a circulation path.

A part of the air is branched from the duct 17 and guided to a cooling chamber 18 such as a refrigerator, and is discharged to the outside of the machine from an exhaust port 19.

In the above configuration, the air containing carrier vapor in the fixing drying chamber 1 is circulated by the blower 16, and a part of it is sent to the exhaust port 1.
9 to the outside of the machine, the pressure inside the fixing drying chamber 1 is below atmospheric pressure.

Therefore, the air containing a high concentration of carrier vapor in the fixing/drying chamber 1 does not actually leak outside through the unavoidable gap, but rather a small amount of air is sucked through the gap.

An amount of air commensurate with that amount is discharged to the outside of the machine from the exhaust port 19.

The method for recovering the carrier liquid will be explained below.

The heat exchange condenser 14 shown in FIG. 2 is a cross-flow type heat exchanger in which thin plates 20 with good thermal conductivity are stacked with spacers 21 interposed therebetween.

The cooling side has a three-stage configuration, and in the first stage 14, the air A3, which is cooled to room temperature, completes recovery of the carrier liquid, and returns to the fixing/drying chamber 1, is used for cooling.

Further, the second and third stages 14□ and 143 are cooled by air C sucked in by the fan 22.

The high temperature air A containing a high concentration of carrier vapor led from the fixing drying chamber 1 is cooled to near room temperature while passing through the heat exchange condenser 14 as described above.

As a result, the carrier vapor in the air becomes supersaturated, and some of it condenses and adheres to the wall of the condenser, grows into large droplets, and falls.

In addition, most of the remaining liquid becomes minute droplets in the air and floats in the air as mist.

The air A2 thus cooled to near room temperature and containing carrier vapor mist is then led to the mist collector 15.

As shown in FIG. 3, the mist collector 15 has an electrode plate 23 to which a high DC voltage is applied and an electrode plate or electrode mesh 24 that is grounded and are insulated from each other and arranged at an appropriate distance. A needle end discharge electrode 25 is provided on the high voltage electrode plate 23 .

The mist floating in the air A2 passes through the corona discharge between the needle-end discharge electrode and the ground electrode, and the charged mist is then affected by the Coulomb force as it passes through the electric field between the electrode plates. It is attracted to the earth electrode, adheres to it, and drips.

With this mist collector, the mist in the air A2 is almost completely removed (90% or more), but the remaining carrier mist is removed by a simple filter 26 such as a wire mesh installed next.
The air A3, which has been completely removed by the blower 16 and contains only a small amount of carrier vapor (saturated vapor at room temperature), is returned to the fixing/drying chamber by the blower 16 and used again.

The carrier liquid liquefied in the heat exchanger/condenser 14 and the mist collector 15 is collected from the drain port 27 into the tank 28,
It can be returned to the developer and reused.

On the other hand, a part of the air A3 branched from the duct 17 is further extremely cooled in the cooling chamber 18, and almost all of the carrier vapor in the air is liquefied before being released into the outside air.

Therefore, this exhaust gas A5 is not only small in quantity but also completely purified, so it does not pose any health hazard.

Details of the tank 28 are shown in FIG.

The tank 28 for collecting developer carrier vapor and storing the recovered liquid has a first partition wall 280 and a second partition wall 28□, and the recovered liquid is divided by the second partition wall 282 until a certain amount is reached. In the first chamber (right side), the carrier liquid recovered by the recovery device, water, and other impurities are mixed and dripped into the tank 28 through the drain port 27 .

The first partition wall 28□ is for protection to prevent the mixed liquid of the carrier liquid and water from directly running on the surface of the recovered liquid and exceeding the second partition wall, and its lower end 28□ is at least the upper end of the first partition wall. 28
□It is below a.

The above mixed liquid (carrier liquid + water) is first stored in the first chamber, and as time passes, the carrier liquid becomes The water 41 is completely separated into the upper layer, and the water 42 is completely separated into the lower layer.

As already clear, the carrier liquid constituting the developer is
Since they are required to be insulating and moisture cannot be mixed in, they are completely separated in the first chamber, and then when the amount exceeds a certain level, only the upper layer of the Isopar H liquid is transferred to the top 28□ of the second partition wall 282. a overflows and collects in the second ventricle (left ventricle).

The carrier liquid collected in the second chamber is transferred to the motor 29 and the rotating shaft 3.
The liquid developer is returned through a pipe 32 by a pump 31 driven by a pump 31 to a developer tank D, which is a liquid developer storage section of the developing means, and is reused as a developer.

However, in this case, since the carrier liquid does not contain a developer, it is necessary to add an appropriate concentrated developer and control the developer using a toner concentration regulator or the like.

In the recovered liquid processing tank 28 configured as described above, liquid level detection means are further provided in the first and second chambers, respectively.

In particular, in the first chamber, the collected and stored water must not overflow the second partition wall 282, so the liquid level in the upper and lower two layers and the lower layer is detected, and if the water level exceeds a certain level, , need to be removed.

This detection means, shown in Figure 4, detects the level based on the difference in dielectric constant between the carrier liquid and water, and detects the change in dielectric constant between two conductive plates that face each other closely. This circuit is shown in FIG.

When the water in the lower layer reaches a certain level or higher, the electromagnetic valve V1 is opened for a certain period of time by an electric signal, and the water is dropped into a tank 36 located approximately below the tank 28.

The solenoid valve (1), which is opened for a time when the moisture 42 has completely fallen off, is then closed and the recovered liquid is stored again.

Further, in the second chamber, in order to control the liquid level within a certain range, there are a float 33 as a level detection means, an actuator 34 actuated by the float 33, and a microswitch MS 1 actuated by the actuator 34.
, MS 2 is installed, MSl detects the upper limit of the liquid level, MS detects the lower limit, and the operating circuit is shown in Fig. 7.
S2 is a normally closed contact type, and when the float 33 floats and the actuator 34 leaves the micro switch MS2, the MS
2 is turned ON and the liquid level further rises, causing the actuator 34
When M and S1 are turned ON, the relay RL-A is activated, and therefore the contact a-1 of the relay is turned ON, the motor M29 is activated, and the carrier liquid is pumped into the developing tank D by the pump 31.

Also, if the current status is 5, MSl will turn off immediately and almost no carrier liquid 41 can be pumped up, so the relay is further held at contact a-2 of relay BL-A and MS
The motor continues to operate even when l is turned off, and the motor M is turned off and the pump operation is stopped only when the lower limit detection microswitch MS2 of the liquid level is turned off.

In addition, Fig. 5 shows the liquid level of the lower layer liquid in the first chamber by the float 4.
0 and is detected by micro switch MS3, upper and lower 2
A float 40 is formed at the interface between the two layers by utilizing the difference in specific gravity of the layers (0.75 and 1).

When the float 40 reaches a certain level or higher, the MS3 is activated, which opens the electromagnetic valve (1) and drops the lower liquid into the tank 36 below.

Further, in this embodiment, a micro switch MS4 for liquid level detection, an actuator 38, and a float 37 are installed in the developing section, and a large amount of carrier liquid (IH) is stored in advance in the second chamber of the tank 28, and the carrier liquid recovered by the recovery device is stored in advance. liquid (I
H) is mixed by overflowing from the first chamber, and the pump 31 is operated by the operation of the liquid level detection device in the developing section to supply the liquid to the developing section.

Further, not only the carrier liquid but also the developer may be stored in the second chamber in advance, and the recovered carrier liquid may be mixed with this and circulated to the developing device.

Next, the electric circuit shown in FIG. 6 will be explained.

1 is a base tuned oscillation circuit, 2 is a voltage doubler detection circuit, and 3 is a detection output voltage amplification circuit and a thyristor IJ gar circuit, which change the tuning frequency of the detection circuit by changing the capacitance of the capacitor CX. filled with C
The capacitance of X increases compared to when air or isopar is filled between the electrodes, and the tuning frequency decreases.

The closer the tuning frequency f1 is to the frequency end fo of the oscillation circuit, the higher the output voltage of the detection circuit can be taken, and this can be used to detect the level.

That is, the oscillation frequency of the dotted line frame 1 is f. If CX is now filled with water, the tuning frequency f1 of T2 becomes f1~fo, and the output voltages Ei and Er are VR such that Ei>Er.
The output voltage E is regulated by amplifier A.

occurs. This is adjusted to a value sufficient to trigger the thyristor SCR.

When the thyristor SCR is triggered, K is energized and becomes 1
・K2 closes, motor M rotates, MS2 closes, and valve opening/closing solenoid SL is also energized to open the valve.

When motor M rotates and MSl is pushed by cam 1, MSl opens, thyristor SCR turns off, K is also de-energized at the same time, and K2 opens and SL's excitation is also cut off, closing the valve.

Even if K opens, motor M continues to rotate because MS2 is closed, but when cam 2 pushes MS2, MS2 opens and motor M stops, preparing for the next operation.

The present invention has the above-mentioned structure, and the collected liquid containing the evaporated carrier liquid from the developing section and the fixing section is collected in the first stage.
It is collected in a tank with a partition wall and a second partition wall, and can be completely separated using the difference in specific gravity between the carrier liquid and water.The separated carrier liquid is returned to the developing tank and can be reused, making it very economical. The present invention provides a developing solution reusing device.

To summarize the effects of the present invention as described above, the present invention uses the above-mentioned configuration to collect and remove the carrier liquid from the air with a difference in specific gravity (by the way, when Isopar is used as the carrier liquid, Isopar is 0.75: water: 1). This system separates moisture and other impurities contained in the air and copying materials that are collected at the same time.

Therefore, in the present invention, it is possible to completely separate the carrier liquid, which must be insulating and must not allow moisture to be mixed in, from moisture with a simple structure.

This certainty of separation makes it possible to circulate the carrier liquid back to the development means and reuse it.

In other words, by using the present invention, it is possible to reliably separate the carrier liquid from other components, mainly water, so that even if the carrier liquid is circulated and reused in the developing means, the developing ability will decrease. There is no risk of causing
Carrier liquid can be used without waste.

Further, in the present invention, there is provided a means for causing the carrier liquid separated by the recovery liquid storage means to overflow from the image storage means, a carrier liquid storage means for storing the carrier liquid overflowed by the means, and a carrier liquid storage means for storing the carrier liquid from the carrier liquid storage means. In other words, the carrier liquid separated by the recovery liquid storage means is once stored in the carrier liquid storage means that stores only the carrier liquid by overflowing, and then is transferred from there. It is circulated to the developing means.

Therefore, in the present invention, when circulating the carrier liquid from the carrier liquid storage means to the developing means, only the carrier liquid is stored in the carrier liquid storage means, even if the carrier liquid is sucked up by a pump or the like. There is no risk of contamination with separated water, etc.

Therefore, for example, the suction capacity of the pump can be freely adjusted.

Further, since the recovered liquid is not circulated to the developing means at an intermediate stage where it is separated into the carrier liquid and water, only the carrier liquid can be reliably circulated to the developing means.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a copying machine adopting an embodiment of the present invention, FIG. 2 is a perspective view of an example of a condensing means for heat exchange, FIG. 3 is a perspective view of an example of a mist collecting means, and FIG. FIG. 4 is a schematic diagram showing a first embodiment of the invention, and FIG. 5 is a schematic diagram showing a second embodiment of the invention. Figure 6 is an electrical circuit diagram for detecting changes in the dielectric constant of the electrode plate.
FIG. 7 is an operating circuit diagram for detecting the upper and lower limits of the second chamber. 27 is a drain port, 28 is a tank, 28 is a first partition, 28
2 is a second partition, 29 is a motor, 31 is a pump, 32 is a pipe, 33, 37, 40 are floats, 35 is an electrode plate,
- 36 is a drainage tank, 41 is a carrier liquid, and 42 is water.

Claims (1)

[Scope of Claims] 1. A developing means for developing a latent image using a liquid developer; a drying section for drying a copying material having a liquid developed image developed by the developing means; a recovered liquid storage means for recovering the carrier vapor, storing the recovered liquid and separating the carrier liquid in the recovered liquid from moisture by utilizing the difference in specific gravity; and the storage means for storing the carrier liquid separated by the recovered liquid storage means. A liquid development copying apparatus comprising: means for overflowing the carrier liquid; carrier liquid storage means for storing the carrier liquid overflowed by the means; and means for circulating the carrier liquid from the carrier liquid storage means to the developing means. . 2. In the invention described in claim 1, there is provided a means for detecting an increase in a water layer with a high specific gravity, and the water liquid has reached a level of a certain amount or more in response to the detection by the detection means. A liquid developing copying apparatus characterized in that the liquid developer is discharged from a storage means.