JPH09171305A - Wet type image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process secondarily recovered water in an image forming device by evaporation, at the time of recovering carrier liquid vapor generated in a fixing part, etc. SOLUTION: The water which is located on the lower layer side, because of a specific gravity difference and separated from a carrier liquid, in a separating part and discharged through a drain pipe 41 is supplied to an evaporating part 32. In the evaporating part 32, plural evaporating plates 36 are arranged side by side in the vertical direction, in a state where the evaporating plates 36 are alternately inclined, a drain port is provided in an uppermost part and the water discharged from the drain port is diffused and evaporation-processed while the water flows on the plates 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet image forming apparatus such as a copying machine, a facsimile and a printer, which uses a wet developing device, and more specifically, a carrier liquid is discharged from a recording material such as a transfer paper on which a toner image is formed. The present invention relates to a wet image forming apparatus including a carrier liquid vapor recovery device that recovers carrier liquid vapor from a fixing device that evaporates.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made for the above carrier liquid vapor recovery apparatus. For example, in Japanese Unexamined Patent Publication No. 48-82835, a liquid developer carrier liquid vapor generated in a copying machine is introduced into a vapor cooling atomization chamber in which a large box-shaped surface is attached to an exterior plate of the copying machine. A developer carrier liquid vapor recovery apparatus has been proposed, which is sucked and collected, and then atomized into droplets, and then introduced into a liquefaction chamber and liquefied. Further, Japanese Patent Application Laid-Open No. 48-83838 proposes that the liquid developer carrier liquid liquefied and recovered in the liquefaction chamber is introduced to a developer liquid tank, a carrier liquid replenishment tank, a cleaning liquid supply device, and the like for reuse. There is.
Further, in Japanese Patent Application Laid-Open No. 49-22145, a storage chamber (tray) for a copy paper (photosensitive paper or transfer paper) after fixing and drying is airtight so that the air flowing in along the sent copy paper is A liquid developing type electrophotographic copying apparatus has been proposed which is configured to process a carrier liquid vapor and a carrier liquid vapor that evaporates continuously in an apparatus.

[0003]

The carrier liquid recovered and liquefied by the conventional carrier liquid vapor recovery device contains water, and this water is supplied to the latent image carrier together with the carrier liquid which constitutes the developing solution. Therefore, it is necessary to separate water from the recovered liquid in order to leak the latent image charge. By the way, this separated water is not reused, so if there is no drainage facility, it must be stored in a tank or the like and discarded regularly or when it is detected that the tank or the like is full. As a result, the maintainability of the device is significantly impaired.

The present invention has been made in view of the above background, and an object of the present invention is to provide a wet image capable of evaporating the water secondarily recovered when the carrier liquid vapor is recovered in the apparatus. A forming device is provided.

[0005]

In order to achieve the above object, the invention of claim 1 is a wet image having a developing device using a developing solution composed of a carrier liquid and a toner, and a carrier liquid vapor recovery device. In the forming apparatus, the carrier liquid recovery device is configured by using a liquefaction unit that liquefies the recovered carrier liquid vapor and a separation unit that separates the liquid generated by the liquefaction unit into carrier liquid and water, It is characterized in that an evaporation means is provided for evaporating the water separated by the separation means.

According to a second aspect of the present invention, in the wet image forming apparatus according to the first aspect, the vaporizing means is provided with a blowing means for promoting the vaporization.

[0007] The invention according to claim 3 is the invention according to claim 1 or 2.
In the wet image forming apparatus, the hydrophilic sheet is used as a member constituting the evaporation means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a wet color electrophotographic copying machine (hereinafter referred to as a copying machine) which is a wet image forming apparatus will be described below. FIG.
FIG. 1 (a) is a front view showing a schematic internal structure of a copying machine to which the present invention is applicable, and FIG. 1 (b) shows an internal structure of a carrier liquid vapor recovery apparatus main body portion arranged on the right side of the copying machine. It is a right view shown. This copying machine has a plurality of photoconductors 10 corresponding to a plurality of colors, forms an electrostatic latent image on the surface of each photoconductor by an electrophotographic method, and develops the electrostatic latent image by a wet developing device 11. Then, the image is transferred to a transfer sheet, fixed by a fixing section having a heat roller pair 12, and then discharged to a sheet discharge section having a sheet discharge tray 13 to make a color copy. Here, the developing device uses a developing solution in which toner is dispersed in a solvent as a carrier solution. As this solvent, an organic solvent such as an isoparaffin-based solvent having a high volume resistivity, for example, Isopar (trade name) manufactured by Exxon Corporation is generally used. Since the copying machine shown in the drawing conveys the transfer paper so as to sequentially face the plurality of photoconductors, the conveying belt 1
4 is used.

The carrier liquid vapor recovery device of this copying machine is
The carrier liquid vapor generated by the fixing operation is trapped in a collecting chamber 21 formed by covering the fixing unit and the paper discharging unit with a cover member 20 so as to be in a sealed state as much as possible. A first duct portion 23 as an air cooling mechanism for inclining air containing liquid vapor so as to be connected to the suction port 22 and become lower toward the downstream side of the air flow, and for air cooling the high temperature air from the collection chamber 21, and the duct. After passing through the liquefying section 24 provided at the terminal end of the section, suction is performed by a suction fan 25 as an air flow generating device. As will be described later in detail, the liquefying unit 24 liquefies the carrier liquid vapor contained in the passing air, the vapor from the transfer paper, and the moisture originally contained in the air. The air blown out from the suction fan 25 in response to this liquefaction process passes through the second duct portion 26 that guides the air along the outer wall of the first duct 23,
It flows into the collection chamber 21 via the inflow port 27.

The carrier liquid and water liquefied in the liquefying section are placed under the separating section 29 for separating the carrier liquid and water through the flow-down port 28 provided in the bottom wall of the liquefying section 24 due to its own weight. Flowing into the liquid receiver 30 of. This separation unit 2
As will be described in detail later in 9, separation into carrier liquid and water,
The carrier liquid is stored in the storage tank 31, and the water is evaporated in the evaporation unit 32.

The liquefaction unit 24 performs a liquefaction process by cooling. For this cooling, a fin ever having a plurality of fins 33 is provided above the downflow port 28 in the liquefaction unit, and the fin ever is connected to a compressor 34 by a refrigerant pipe 35.

In the liquefying unit 24, the air containing the carrier liquid vapor that has been air-cooled to some extent in the liquefying unit 24 is cooled to a temperature at which the carrier liquid can be sufficiently liquefied by using a refrigerant. As a result, the carrier liquid or the like is attached as droplets to the fins 33 and the inner wall surface of the liquefying portion, and is collected in the downflow port 28 by its own weight.

The separation unit 29 separates the water and the carrier liquid by utilizing the difference in specific gravity (for example, the specific gravity of the isoparaffin organic solvent is 0.7 to 0.8 with respect to water).
Due to this separation, as shown in FIG. 2, the liquid receiver 30 having an upper opening and an overflow port 30a on the side wall is provided.
And an overflow liquid guide member 40 that covers the overflow port 30a from the outside and receives the overflowed liquid inside and guides it to the carrier liquid storage tank 31.
And a drain pipe 41 that connects the liquid discharge port 30b of the liquid container 30 and the evaporation unit 32 formed at a position lower than the overflow port 30a.

In the drainage pipe 41, the uppermost position 41a of the inner bottom wall at the end on the evaporation portion side can be located at the lower end position of the overflow port 30a, and the overflow liquid level H can be set.
And the pipe portion between the uppermost position 41a and the liquid receiver drain port 30b is lower than the overflow liquid level H. Then, a water injection port 50 is formed at the end of the evaporation unit 32 side so that the opening is higher than the uppermost position.

The overflow port 30a has a hole diameter of 2
A mesh 44 that is in the range of 0 μm to 200 μm is filled. The mesh 44 has a property of allowing a carrier liquid to pass therethrough and not allowing water to pass therethrough. It is considered that such a mesh 44 can be used for separating the carrier liquid of the developer and the water due to the difference in wettability of the carrier liquid and the water with respect to the mesh 44. Suitable materials for this mesh include stainless steel, nylon, polyester, polyethylene, polypropylene, tetron, glass, and fluororesin.

In the present example, the flow-out port 2 of the liquefaction section 24
A chain whose upper end is attached to the structure of the liquefying section 24 so that the liquid can smoothly flow down from 8 to the liquid surface in the liquid receiver 30 and whose freely movable lower end reaches below the overflow liquid H 51 is provided.

In the above separating unit 29, when the apparatus is installed, water is injected from the water inlet 50 into the intermediate portion of the drainage pipe 41 which is located lower than the overflow liquid level H, and the water is received in advance in the liquid receiver 30. This water is introduced and the water level is set to a level slightly lower than the overflow liquid level H.
In this state, the liquid receiver 30 receives the mixed liquid of the carrier liquid and water from the downflow port 28 of the liquefying unit 24. The mixed liquid received in the container is separated in the container 30 by the specific gravity so that the liquid layer of the carrier liquid may face upward. And
The carrier liquid in the carrier liquid layer above the overflow liquid level H overflows from the overflow port and is stored in the carrier liquid storage tank 31 through the overflow liquid guide member 40. While receiving the liquid from the liquefying unit 24, separating the carrier liquid and water due to the difference in specific gravity, and overflowing the separated carrier liquid, the middle portion of the drain pipe 41 is sandwiched and the liquid receiver is held. Three
The liquid level tries to balance between the 0 side and the uppermost position 41a side of the end portion of the drainage pipe. That is, when the amount of liquid in the liquid receiver 30 increases, the drain pipe 41
The liquid level at the end of the evaporation part of the device also tries to rise. But,
The uppermost position 41a at this end is an overflow position toward the evaporation portion side, and water that attempts to exceed this overflows and is stored in the evaporation portion. Moreover, the highest value 41a coincides with the overflow liquid level in the liquid receiver 30. As a result, the liquid level in the liquid receiver 30 is maintained almost at the overflow liquid level, and the liquid receiver 3
Within 0, the relationship in which only the liquid layer of the carrier liquid formed by the separation due to the difference in specific gravity faces the overflow port 30a is maintained.

The evaporating section 32 is located on the lower layer side in the separating section 29 due to the difference in specific gravity, separates the carrier liquid and the water discharged through the drain pipe 41, and evaporates the water. The opening 52 of the drainage pipe 41 may be the cross-sectional shape of the pipe as it is, but may be, for example, a trumpet shape as long as it can promote evaporation. This evaporation unit 32 is shown in FIG.
As shown in (b) and (b), a plurality of evaporation plates 36 are arranged in a vertical direction alternately in a slanted form, and the water discharged from the drainage port provided at the top flows on the plate 36. Evaporation is promoted by diffusing into and increasing the surface area. The structure of the evaporation unit 32 is not limited to such a structure, and the evaporation plate 36 may be provided in a spiral shape as long as the evaporation is promoted. In addition, at the bottom, there is a plate 37 that receives the water when it exceeds the evaporation capacity.
In addition, a float sensor 38 is provided to detect when the plate 37 is full. When any abnormal state is detected, the liquid overflow is prevented by detecting this and performing sequence control so that a new copying operation cannot be started. Further, in order to promote evaporation, a heater may be embedded in the plate 36. Further, the vaporized water vapor evaporates until the vapor pressure in the vicinity of the vaporizing portion reaches a saturated state. However, when the vapor pressure reaches the saturated state, the vaporization speed decreases. In order to promote evaporation, a heating means may be combined with the blower fan 39 to send hot air. The evaporation unit 32 has a structure in which all surfaces are opened to the outside so that evaporation is promoted by sharing a space with the outside. Further, in order to increase the surface area by promoting the spread of water on the evaporation plate 36 and improve the water retention on the surface of the plate 36, it is preferable to use the plate 36 covered with a hydrophilic sheet. desirable. An example of such a hydrophilic sheet is a non-woven fabric made of cotton.

In this copying machine, the second duct portion 26, through which the air whose vapor has been liquefied and removed in the liquefying portion 24, is extended and connected to the inflow port 27 formed in the collecting chamber 21. The first duct portion 23, the liquefaction portion 24, and the second duct portion 26 form a closed annular space, and air is circulated in the annular space.

FIG. 3 is a schematic configuration diagram of another copying machine to which the present invention can be applied. The photosensitive drum 10, which is an image carrier,
During copying, it is rotationally driven at a constant speed in the direction of the arrow by a driving device (not shown), and is uniformly charged by a charging charger 2 such as a corona discharger. Then, an image is formed on the photosensitive drum 10 by an exposing device (not shown). Laser light 3 modulated on the basis of a signal scans, a document image is projected, and an electrostatic image is formed by the exposure light.
The outside of the image forming area is neutralized by the sensor 4, and the image is developed by the wet developing device 11. The electrostatic image on the photoconductor drum 10 is visualized as a toner image by the developing device, and this toner image is fed from a paper feeding device (not shown) and transferred onto the transfer paper 7 fed by the feeding roller 6. Transfer is performed by a charger (transfer electrode or transfer roller may be used instead of the transfer charger) 8. The transfer paper 7 after the transfer is separated from the photoconductor drum 10 and is transferred while being electrostatically adsorbed to the transfer belt 10 serving as a transfer material transfer device, and the toner is fixed by the fixing device 60 and a paper discharge unit (not shown). It is discharged to. After separating the transfer paper 7, the photoconductor drum 10
The cleaning unit 5, which is a cleaning device, removes the residual toner, and the static elimination lamp or static elimination charger 9 removes the residual potential to prepare for the next copy.

The wet developing device 11 is provided with a developing roller 1 and a squeeze roller 64, and faces the photosensitive drum 10 while being adjusted and held at a minute interval, for example, 0.1 to 0.2 mm, and indicated by an arrow. Is rotated at a peripheral speed higher than that of the photoconductor drum 10 in a direction opposite to the rotation direction of the photoconductor drum 10 shown in FIG. To the developing rollers 1 and 64, the tips of the scrapers 16 and 42 serving as cleaning members fixed to the developing container 15 come into contact, and the toner on the developing rollers 1 and 64 is always cleaned. At the upper end of the toner container, a supply nozzle 17 serving as a liquid supply unit for supplying the developing solution is provided, and the developing solution is supplied into the developing container 15. Here, a developer in which toner is dispersed in a solvent as a carrier liquid is used as the developer. As the solvent, an organic solvent such as an isoparaffin type having a high volume resistivity, for example, Isopar (trade name) manufactured by Exxon Co. is used. The supply nozzle 17 is supplied with the developing solution from the developing solution tank 61 by a supply device 60 such as a pump driven by a pump motor 19 through the conduit 20. The developing solution supplied into the developing container 15 is carried to the surface of the photosensitive drum 10 by the cooperation of the developing roller 1 and the scraper 16, and flows between the photosensitive drum 1 and the developing rollers 1 and 64. To develop the image on the photosensitive drum 10.

The excess developer passed between the photosensitive drum 10 and the developing roller 13 and the developer used for the development are used as the bottom of the developer container 15 for receiving the liquid.
Collected in 2. Further, the developing solution remaining on the surface of the photoconductor drum 10 is driven to rotate in the same direction as the photoconductor drum 10, and is squeezed by the squeeze roller 64 arranged at a minute interval of 0.05 mm from the photoconductor drum 10. The developer scraped off and attached to the squeeze roller 64 is further scraped off by the scraper 76. Further, in order to increase the cohesive force of the toner image formed on the photoconductor drum 10 on the surface of the photoconductor, the electric field roller 65 is arranged at a minute distance from the photoconductor drum 10, and an electric field having the same polarity as the toner is applied. ing. The liquid receiving portion 62 is provided with a liquid discharge port 65, and the developing liquid from the discharge port 65 is returned to the developing liquid tank 61 by a recovery pipe 66. As a result, the developer is circulated and supplied.

The cleaning unit 5 includes a cleaning roller 6 arranged so as to be in pressure contact with the photosensitive drum 10.
7 and a cleaning blade 73. The cleaning roller 67 is formed as, for example, a sponge-like foam roller, and the cleaning blade 73 is formed of an elastic body such as rubber. The developing solution is supplied from the developing solution tank 61 by the supply device 60 through the conduit 18 to the cleaning solution supply section formed at the upper end of the cleaning container 68. Then, the cleaning liquid supplied by the cleaning liquid supply unit is supplied to the cleaning roller 67. The cleaning roller 67 is the photosensitive drum 1.
The residual toner and paper dust are collected from 0, and the cleaning liquid containing the collected toner and paper dust is collected by the cleaning roller 6
The toner is squeezed by the squeezing roller 69 arranged in contact with the nozzle 7 and collected in the liquid receiving portion 62 formed at the bottom of the cleaning container 68. The squeeze roller 69 scrapes off the toner and the cleaning liquid by the scraper. The liquid receiving portion 62 has a liquid discharge port 71, and discharges the collected cleaning liquid to the developer tank 61 through a recovery pipe. When the liquid supplied by the cleaning liquid supply unit is supplied to the cleaning roller 67 as it is, it does not reach the entire length range of the cleaning roller 67, so that the liquid diffusion plate 72 is provided.

A fixing device 60 for fixing the transfer paper 7 after the transfer.
Has a fixing roller 12 having a heater 77 built therein and a pressure roller 12. When the transfer paper 7 passes through the nip between both rollers 12, the toner image on the transfer paper 7 is fixed by receiving heat from the heater 77 of the fixing roller 12. At this time, the heat applied from the fixing roller 12 melts and fixes the toner, and at the same time, the carrier liquid vapor contained in the transfer paper 7 is generated. The transfer paper 7 after fixing is the discharge tray B.
Alternatively, it is carried to a conveyance path for double-sided transfer. At this time, in order to efficiently collect the carrier liquid vapor generated by the fixing operation, the carrier liquid vapor collection chamber 21 is covered so that both the fixing portion and the paper discharge portion or the vicinity of the fixing portion are in a sealed state as much as possible. Air that contains a large amount of carrier liquid vapor is sucked from the collection chamber 21 through the suction port 22. Although an example of a single-color copying machine is shown here, full-color copying can be performed by repeating the transfer operation a plurality of times.

[0025]

According to the carrier liquid vapor recovery apparatus in the wet image forming apparatus of the first to third aspects, since the recovered and liquefied liquid is separated into carrier liquid and water, the carrier liquid does not contain water. Only can be extracted. Therefore, the recovered carrier liquid can be satisfactorily reused. Also,
Since the water separated by the separation means can be evaporated by the evaporation means, the water that is not reused can be evaporated in the apparatus. Therefore, when there is no drainage facility, the labor of storing this water in a dedicated storage tank and periodically or appropriately detecting and discarding it can be omitted.
Therefore, the maintainability of the device related to the water treatment can be improved.

In particular, according to the wet image forming apparatus of the second aspect, since the blowing means for accelerating the evaporation is provided in the evaporation means, the air flow can be created in the vicinity of the evaporation plate. Therefore, it is possible to prevent the water vapor pressure from reaching a saturated state near the plate of the evaporation means, so that the evaporation capacity of the device can be maintained and promoted.

Further, according to the wet image forming apparatus of the third aspect, since the hydrophilic sheet is used as the member constituting the evaporation means, the surface area is increased by promoting the spread of water on the evaporation plate. The water retention on the plate surface can be improved with the increase. Therefore, the evaporation capacity of the evaporation means can be improved, the surface area of the plate can be reduced as compared with the case of using only the plate, and the device can be downsized.

[Brief description of the drawings]

FIG. 1A is a front view schematically showing the inside of a copying machine to which the invention can be applied. FIG. 3B is a right side view schematically showing the inside of the carrier liquid recovery device main body of the copying machine.

FIG. 2 (a) is an enlarged explanatory view of a main part of the carrier liquid recovery apparatus. (B) The right view of the evaporation part of the carrier liquid recovery device.

FIG. 3 is a front view showing the outline of the inside of the copying machine according to the embodiment of the present invention.

[Explanation of symbols]

 10 Photoconductor 11 Developing Device 12 Fixing Roller 20 Cover 21 Collection Chamber 22 Suction Port 23 First Duct Part 24 Liquefaction Part 25 Suction Fan 26 Second Duct Part 28 Downflow Port 29 Separation Part 30 Liquid Receptor 30a Overflow Port 30b Discharge Port 31 Carrier liquid storage tank 32 Evaporator 33 Cooling fin 34 Compressor 35 Refrigerant pipe 36 Evaporating plate 37 Dish 38 Float sensor 39 Blower fan 40 Overflow liquid receiving member 41 Drain pipe 44 Mesh 50 Water inlet

Claims (3)

[Claims] 1. A wet image forming apparatus having a developing device using a developing solution composed of carrier liquid and toner, and a carrier liquid vapor recovery device, wherein the carrier liquid recovery device liquefies the recovered carrier liquid vapor. Means and a separating means for separating the liquid generated by the liquefying means into a carrier liquid and water, and an evaporation means for evaporating the water separated by the separating means is provided. Characteristic wet image forming apparatus. 2. A wet image forming apparatus according to claim 1, wherein the evaporation means is provided with a blowing means for promoting evaporation. 3. The wet image forming apparatus according to claim 1 or 2, wherein a hydrophilic sheet is used as a member constituting the evaporation means.