JPH0683155A - Humidity control device - Google Patents

Abstract

PURPOSE:To make the capacity of a refrigerating and dehumidifying means small and to save space in the case of setting it in a device by increasing dehumidifying efficiency and to eliminate the need of special control or processing for waste water caused by dehumidification. CONSTITUTION:The refrigerating and dehumidifying means 400 de-humidifying the inside of an image forming device 200 by an electrophotographic process is provided, and the air inlet 451 and the air exit 452 of the low temperature part 403b of the means 400 are opened inside the device 200, and the air inlet 454 and the air exit 455 of the high temperature part 403c are opened outside the device 200, respectively, whereby the waste water caused in the low temperature part 403b is introduced into the high temperature part 403c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity control apparatus, and more particularly to a humidity control apparatus for controlling the humidity inside an image forming apparatus by an electrophotographic process by freezing and dehumidifying means.

[0002]

2. Description of the Related Art Humidity affects characteristics such as charging, exposure, development and transfer in an electrophotographic process, and makes image quality such as image density unstable.

In Japanese Patent Laid-Open No. 52-134733, a humidity sensor detects the humidity of a specific portion in a copying machine utilizing an electrophotographic process, and a humidifying means is activated according to the output of the humidity sensor to determine the specific portion. A technique is disclosed in which the developer is dehumidified by a desiccant while being adjusted to the humidity of.

As a result, it is possible to prevent the characteristics of the electrophotographic process in the specific portion from varying with humidity, and to prevent the characteristics of the developer from being affected by high humidity. Therefore, the image quality can be stabilized.

[0005]

However, providing the dehumidifying section with a desiccant requires regeneration or replacement when the desiccant becomes saturated, which results in high cost. Further, it is disadvantageous in that it is difficult to turn on / off the dehumidifying function and the predetermined humidity is maintained.

Instead of this, the present inventors have considered to employ a dehumidifying means utilizing a freezing function, and in combination with the humidifying means, keep the humidity inside the copying machine constant, and not the partial electrophotographic process. Proposes a copying machine capable of suppressing fluctuations in each of the characteristics described above due to humidity.

In the dehumidification utilizing such a freezing function,
Condensation water is generated, and it is necessary to dispose of it. It is inconvenient to handle and manage the image forming apparatus if it is discarded regularly. In addition, the use of the freezing and dehumidifying means has a problem that the heat of the high temperature portion easily affects the electrophotographic process.

Further, there is a problem in that the capacity is increased and the size is increased due to the higher function of the apparatus such as the adoption of the freezing and dehumidifying means.

An object of the present invention is to provide a humidity control apparatus which can avoid such a problem extremely easily.

[0010]

In order to achieve the above-mentioned object, the present invention comprises a freezing / dehumidifying means for dehumidifying the inside of an image forming apparatus by an electrophotographic process, and intake of a low temperature portion of this freezing / dehumidifying means. It is characterized in that the inlet and the exhaust port are opened inside the device, and the intake port and the exhaust port of the high temperature part are opened outside the device, respectively, so that the wastewater generated in the low temperature part is introduced into the high temperature part.

In this case, it is preferable that the temperature adjusting means uses the freezing function of the Peltier element.

[0012]

The freezing / dehumidifying means is brought into contact with the air in the device where the low temperature part is inhaled and exhausted through the intake port and the exhaust port opened in the device so that the moisture in the air in the device is condensed and captured. The humidity of the inside can be adjusted appropriately.

At this time, the high temperature part is cooled by the air outside the device which is sucked and exhausted through the intake port and the exhaust port which are open to the outside of the device, without being a cause of temperature rise in the device, and is cooled in the low temperature part of the freezing / dehumidifying means. The dehumidification function of can be enhanced.

Further, the wastewater generated in the low temperature part is introduced into the high temperature part, heated and evaporated to be discharged outside the device, and can be spontaneously diffused without affecting the inside of the device.

When the freezing / dehumidifying means is a Peltier element, the dehumidification and the evaporation of the waste water can be carried out by directly providing the heat exchange section at the low temperature section and the high temperature section of the element.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the overall construction of the digital color copying machine of the first embodiment.

This digital color copying machine is roughly divided into an image reader section 100 for reading an original image and a copying section 200 for reproducing an image read by the image reader section.

In the image reader unit 100, the scanner 10 includes an exposure lamp 12 for irradiating a document, a rod lens array 13 for condensing the reflected light from the document, and a contact type for converting the condensed light into an electric signal. The CCD color image sensor 14 of FIG. The scanner 10 is driven by the motor 11 at the time of reading an original, moves in the direction of the arrow (sub scanning direction), and scans the original placed on the platen 15. The image on the document surface illuminated by the exposure lamp 12 is photoelectrically converted by the image sensor 14.

R obtained by the image sensor 14,
The multi-valued electrical signals of G and B are converted into 8-bit gradation data of any one of yellow (Y), magenta (M), cyan (C), and black (K) by the read signal processing unit 20. It is converted and stored in the synchronization buffer memory 30.

Next, in the copying section 200, the print head section 31 performs gradation correction (γ correction) on the input gradation data according to the gradation characteristics of the photoconductor, and then the corrected image. Data is D / A converted to generate a laser diode drive signal, and the semiconductor laser is caused to emit light by this drive signal.

The print head unit 3 corresponding to the gradation data
The laser beam emitted from the laser beam No. 1 exposes the photosensitive drum 41, which is rotationally driven, via the reflecting mirror 37. The photoconductor drum 41 is irradiated with an eraser lamp 42 before being exposed for each copy, and is uniformly charged by a charging charger 43. When exposed in this state, an electrostatic latent image of the original is formed on the photosensitive drum 41. Cyan, magenta, yellow, and black toner developing devices 45
Only one of a to 45d is selected and the electrostatic latent image on the photosensitive drum 41 is developed. The developed toner image is transferred by the transfer charger 46 onto the copy paper wound around the transfer drum 51.

After four colors are transferred to the copy paper, the transfer drum 5
It is separated from 1 and sent to the fixing unit 60. Then, after the fixing process is performed here, the sheet is discharged to the tray 61. Reference numeral 62 is a paper feeding unit.

The change in environmental humidity has a great influence on the image formation by the electrophotographic process in the copying section 200.

For example, FIG. 6 shows the humidity dependence of the developing characteristics. As shown in FIG. 6, when the humidity is high, the amount M of the developer attached to the photosensitive drum 1 is increased and the image density is increased. This is because the charge amount of the developer changes mainly depending on the humidity, which changes the adhesion amount characteristic with respect to the development potential ΔV (developing bias potential V _B −latent image potential V _i ).

Utilizing this, in the present embodiment, the density (ID) of the developed image formed on the photosensitive drum 1 by the development, which is actually affected by the humidity, is used as the AIDC sensor 300.
The humidity inside the copying section 200 is adjusted by the humidity adjuster 400 according to the detection result.

As a result, the humidity in the copying section 200 is
It can be adjusted properly without delay based on one of the characteristic values of the electrophotographic process that is actually affected by humidity, and by adjusting the proper humidity, all of the characteristics that are affected by the humidity of the electrophotographic process can be controlled. Can be stabilized.

The AIDC sensor 300 is an image density detection sensor which is used when the image density is fed back to the control of the developing bias and the exposure amount and the change of the image density with time is automatically corrected. It is provided in front of the transfer portion of the drum 1 and is used in common.

The detection and correction of the image density are performed, for example, by forming a visible image of the test pattern on the non-image portion of the photosensitive drum 41 and detecting the density of the image.

The humidity adjustment may be performed together with this or at an appropriate timing independently.

The humidity controller 400 includes a dehumidifying unit 401 as shown in FIG. 2 and a humidifying unit 40 as shown in FIG.
2 and.

The dehumidifying unit 402 includes a Peltier element 40.
I am using 3.

As shown in FIG. 2, the Peltier element 403 has a low temperature portion 403b and a high temperature portion 403c on both sides of the P / N junction portion 403a, and a cooling fin 405 is provided in the low temperature portion 403b and the high temperature portion 403c. The radiation fins 406 are separately coupled.

The low temperature section 403b and the high temperature section 403c are respectively a low temperature section casing 453 having an intake port 451 and an exhaust port 452 opened inside the apparatus, and a high temperature section casing having an intake port 454 and an exhaust port 454 opened outside the apparatus, respectively. 456 and. Recovered water receiver 40 of low temperature casing 453
A water supply pipe 458 is provided from 8 to the water receiving part 457 of the high temperature part casing 456, and the drainage of the recovered water receiving part 408 is sent to the water receiving part 457 by the pump 459. The radiating fins 406 hang down in the water receiving portion 457 so as to evaporate the waste water sent to the water receiving portion 457 and accelerate the cooling of the high temperature portion 403c.

In the dehumidifying unit 402, the blower fan 40
The air 411 containing the humidity in the copying section 200 is guided into the low temperature section casing 453 by 7. Peltier element 40
The moisture in the air is condensed by the cooling fins 405 attached to the low temperature section 403b of No. 3 as water droplets.
Fall to 8. The dehumidified air 412 is the copy section 200.
Is discharged inside.

At this time, the high temperature portion 40 of the Peltier element 403
The cooling efficiency of the low temperature part 403b of the Peltier element 403 is increased by cooling 3c with the outside air taken into the high temperature part casing 456 by the blower fan 409 via the radiation fins 406 attached thereto, and as a result, the dehumidification efficiency. Goes up.

Particularly, in this embodiment, the high temperature section casing 456 is used.
The waste water collected in the recovered water receiving portion 408 of the low temperature casing 453 is sent to the water receiving portion 457 of the pump 459 through the water feeding pipe 458 by the pump 459, and the radiating fins 406 are immersed in the waste water to be evaporated. The steam 406 is spontaneously emitted from the exhaust port 455 together with the outside air. Therefore, it is possible to save the trouble of disposing the waste water. In addition, the high temperature portion 403c due to the evaporation of the waste water by the radiation fins 406
Cooling is promoted, and the cooling function in the low temperature section 403b can be enhanced by that much, and the dehumidification efficiency can be increased.

Further, since the high temperature section 403c and the high temperature section casing 456 are located outside the copying section 200, the copying section 20
0 space is not used, and in combination with exhausting to the outside of the apparatus, the heat of the high temperature part 403c and the divergent steam generate the copy part 2
It is possible to avoid the influence on the electrophotographic process in 00.

As shown in FIG. 3, the humidifying unit 404 keeps water in the water storage tank 422 so that the cloth film 423 dipped in the water is maintained in a wet state. Therefore, the wind 424 sent by the blower fan 421 passes through the cloth film 423 to become moist air 425. The moist air 425 is sent into the copying section 200 to humidify it.

In this embodiment, as shown in FIG.
The CPU 500 for controlling the operation of the copying machine shown in FIG.

Therefore, in addition to the start signal, the output of the AIDC sensor 300 and other inputs are input to the CPU 500. Further, the dehumidifying unit 403 of the humidity controller 400
And a humidity controller driver 5 for driving the humidifying unit 404
01 operation signal, the operation signal of the pump driver 502 for driving the pump 459, and other outputs.

FIG. 5 is a flow chart showing the main contents of the humidity adjustment control by the control circuit of FIG.

According to this, if the output Vs when the image density of the test pattern is detected by the AIDC sensor 300 is larger than a predetermined value, for example, 3 to 5V, it is determined that the image density is high due to high humidity, and the dehumidifying unit 40
3 and the pump 459 are driven to return.

On the contrary, if the output Vs is smaller than a predetermined value, for example, 2 to 5 V, it is judged that the image density is low due to the low humidity, and the humidifying unit 404 is driven to return.

As a result, the humidity of the copying section 200 is adjusted so as to obtain an image density within a certain range. By this humidity adjustment, fluctuations due to temperature can also be suppressed for all of the characteristics affected by humidity in the electrophotographic process.

Waste water generated by dehumidification is spontaneously emitted outside the apparatus.

In this embodiment, when the amount of water in the water receiving portion 457 increases and reaches the position of the first full-water detecting sensor 461, it is detected by the sensor 461, and it is necessary to treat the water. Notify by turning on the warning lamp. Further, when the amount of water further increases and reaches the second full-water detection sensor 462, the sensor 462 detects it and the dehumidification is stopped.

Therefore, the outputs of these sensors 461 and 462 are input to the CPU 500, and a warning lamp turn-on / off signal is output.

From the recovered water receiving portion 408 to the water receiving portion 457
The drainage can be sent by gravity flow without using a pump. Further, the use of the humidifying unit 402 is not essential.

Further, by utilizing the Peltier element, in addition to the feature of being small and quiet, by sufficiently cooling the high temperature portion, the cooling function in the low temperature portion can be enhanced and the dehumidification efficiency can be increased.

However, in some cases, the present invention can be applied to other dehumidifying means having a refrigerating function.

[0052]

According to the present invention, it is possible to stabilize the image quality by controlling the humidity inside the apparatus by the freezing and dehumidifying means, suppressing the characteristics of the electrophotographic process from varying with humidity.

Especially at this time, the wastewater generated in the low temperature part is introduced into the high temperature part, heated and evaporated to be discharged outside the device and spontaneously diffused without affecting the inside of the device. This eliminates the need for special work and management, and does not complicate handling and management of the image forming apparatus.

Further, the high temperature portion is an intake port opened outside the device,
Because the outside air that is sucked in through the exhaust port and exhausted is cooled without causing a temperature rise inside the device, and is sufficiently cooled by evaporating the drainage,
Combined with the fact that the dehumidifying function in the low temperature part of the freezing / dehumidifying means can be remarkably enhanced, the required capacity of the freezing / dehumidifying means can be reduced and downsized, and the high temperature part may be located outside the device. Therefore, the required space in the device can be reduced, which is practically advantageous.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a digital color copying machine showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a dehumidifying unit.

FIG. 3 is a sectional view of a humidifying unit.

FIG. 4 is a block diagram of a main part of a control circuit.

5 is a flowchart showing control contents of humidity adjustment by the control circuit of FIG.

FIG. 6 is a graph showing the relationship between humidity and image density.

[Explanation of symbols]

 200 Copying part 300 Sensor 400 Humidity controller 401 Dehumidifying unit 403 Peltier element 403b Low temperature part 403c High temperature part 408 Recovered water receiving part 451, 454 Inlet port 452, 455 Exhaust port 453 Low temperature part casing 456 High temperature part casing 457 Water receiving part 458 Water supply Pipe 459 Pump 500 CPU

Claims (2)

[Claims] 1. A freezing / dehumidifying means for dehumidifying the inside of an image forming apparatus by an electrophotographic process, wherein an intake port and an exhaust port of a low temperature portion of this freezing / dehumidifying means are provided inside the apparatus, and an intake port and an exhaust port of a high temperature portion are provided. A humidity control device characterized in that wastewater generated in a low temperature part is introduced into a high temperature part by opening each outside the device. 2. The humidity control apparatus according to claim 1, wherein the temperature control means uses the freezing function of the Peltier element.