JP2000321944A - Solvent recovering device for electrophotographic printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solvent vapor recovering device by which residual solvent in exhaust air after cooling solvent vapor by a heat exchanger is removed by accelerating the separation and condensation of solvent from the solvent steam exhausted after a fixing process in an electrophotographic printer using wet type toner. SOLUTION: In this solvent recovering device 9 for the electrophotographic printer 1 in which the solvent vapor generated at the fixing process of the electrophotographic printer 1 using the wet type toner is guided to the heat exchanger 30 through solvent vapor ducts 31 and 32 and the solvent is recovered by cooling the solvent vapor by the cooling part 4 of the heat exchanger 30 and condensing the solvent, the solvent vapor ducts 31 and 32 are composed of a bellows-like duct consisting of an aluminum material. The solvent vapor ducts 31 and 32 are provided with bend sections 31a and 32a curved at least one part and also are provided with a grounding means grounding a duct wall in midway.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solvent recovery device for recovering a solvent in a wet toner in an electrophotographic printing machine using a wet toner.

[0002]

2. Description of the Related Art FIG. 5 shows a solvent recovery apparatus in an electrophotographic printer using a wet toner in which a toner is dispersed in a solvent such as xylene, alcohol, or benzene, as disclosed in Japanese Patent Application Laid-Open No. 9-204121. An outline of the present invention is shown below. In FIG. 5, reference numeral 1 denotes an electrophotographic printing machine, which is configured as follows. Reference numeral 11 denotes a casing, 12 denotes a web, 13a and 13b denote photosensitive drums, 14a denotes an intermediate fixing roller, and 14b denotes a final fixing roller, and the web 12 is printed by the photosensitive drums 13a and 13b using wet toner.

[0003] The toner transferred to the web 12 by printing on the photosensitive drum 13a of the first stage is fixed to the web 12 by passing the web 12 through an intermediate fixing roller 14a maintained at 100 ° C to 130 ° C. Let
Next, the toner transferred to the web 12 by printing on the photosensitive drum 13b of the second stage is
The web 12 is fixed by passing through a final fixing roller 14b maintained at a temperature of 150C to 150C. When the toner is thermally fixed to the web 12 by the fixing rollers 14a and 14b, the solvent in the toner evaporates and gasifies.

In the present invention, the solvent gasified as described above, that is, the solvent vapor, is sent to the heat exchanger 3 through the gas circulation line 6 by the blower 2 and the heat exchanger 3
Is cooled by heat exchange with the refrigerant in
The liquefied solvent is recovered in the solvent recovery tank 9. The gas from which the solvent has been separated in the heat exchanger 3 is sent to a heating device 5 through a gas circulation line 6, and the temperature is controlled by a temperature control device 7 which operates according to a detection signal from a temperature / humidity sensor 8. After being heated to a predetermined temperature by the heating device 5, it is returned into the casing 11.

[0005] Reference numeral 10 denotes a refrigerant circulation line for circulating the refrigerant to the heat exchanger 3, and 4 denotes a cooler for cooling the refrigerant deprived of the solvent vapor.

[0006]

In such an electrophotographic printing machine, as described above, when the toner image is fixed to the web 12 by the fixing rollers 14a and 14b, the solvent in the toner evaporates and the gaseous solvent vapor is heated. The solvent is coagulated and liquefied by cooling in the exchanger 3, and is recovered in the solvent recovery tank 9. However, as in the case of printing on high-quality paper, especially the double-sided printing thereof, the amount of the solvent absorbed is large. , Final fixing roller 1
4b, the concentration of the solvent vapor passing through the gas circulation line 6 is set to 0.4.
When the content is 2% by volume or more, the concentration becomes extremely high.

However, in the related art, since the gas circulation line 6 is formed of a substantially straight pipe of steel pipe, the solvent vapor transferred from the printing press 1 to the heat exchanger 3 through the gas circulation line 6 is: It is introduced into the heat exchanger 3 without causing collision with the pipe wall in the pipe, and the action of separating the solvent mist from the solvent vapor in the pipe is hardly performed.
The solvent is easily introduced into the heat exchanger 3 with a high solvent concentration.

For this reason, in the prior art, the cooling of the solvent vapor and the condensation of the solvent in the heat exchanger 3 are not sufficiently performed, and the solvent vapor is finally discharged into the atmosphere in the form of white smoke. And contribute to air pollution,
There is a problem that.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, the present invention promotes the separation and liquefaction of a solvent mist from a solvent vapor discharged after a fixing step in a printing machine in an electrophotographic printing machine using a wet type toner, and An object of the present invention is to provide a solvent vapor recovery device capable of removing a residual solvent in exhaust gas after solvent vapor cooling in an exchanger.

[0010]

According to the first aspect of the present invention, a solvent vapor generated in a fixing step of an electrophotographic printing machine using a wet toner is passed through a solvent vapor pipe. In a solvent recovery device of an electrophotographic printing machine in which the solvent is condensed and recovered by cooling the solvent vapor in a cooling section of the heat exchanger, the solvent vapor pipe is made of aluminum material. A solvent recovery device for an electrophotographic printing machine characterized in that the solvent recovery device is configured as a bellows-like tube.

In this invention, the bellows-shaped tube may be a tube having a helical shape or a tube formed by connecting ring pieces having a mountain-shaped cross section in the longitudinal direction.

According to the invention, the solvent vapor generated in the fixing step of the electrophotographic printing machine, that is, the gas generated by evaporating the solvent in the toner in the fixing step, passes through the solvent vapor pipe when passing through the solvent vapor pipe. Since the steam pipe is formed in a bellows shape to form a flow path having a large pressure loss, the solvent vapor collides with an inner wall surface protruding into the pipe, and turbulence spreads, thereby promoting turbulence. Due to the collision with the inner wall surface, the mist in the solvent vapor falls and is separated from the gas.

The collision and the separation of the mist are performed over the entire length of the solvent vapor pipe, whereby the solvent concentration of the solvent vapor flowing into the heat exchanger through the solvent vapor pipe is reduced. Is completely condensed by cooling by a cooler in the heat exchanger,
Collected as liquid.

According to a second aspect of the present invention, in addition to the first aspect, the solvent vapor pipe is formed in a curved pipe portion curved at at least one position. Here, the curved tube portion is
It is preferable to use a curved pipe having a bending angle of 90 ° to 180 °, and it is preferable that the number of the curved pipe portions is large.

According to the invention, the solvent vapor flowing in the solvent vapor pipe collides with the inner wall surface of the pipe when it is bent in the curved pipe part, and the turbulence is promoted. You. As a result, the separation of the mist of the solvent in the solvent vapor is promoted, and the solvent concentration is reduced.

The third aspect of the present invention is the first or second aspect.
In addition to the above, the solvent vapor pipe is provided with grounding means for electrically grounding the pipe wall in the middle thereof.

According to the invention, the solvent mist, which is positively charged at the same potential as the positively charged toner, is electrostatically attracted by setting the potential of the solvent vapor pipe made of aluminum material to zero by grounding. Captured on the inner wall of the solvent vapor pipe,
Adsorbed. In addition, since the solvent vapor pipe is formed in a bellows shape, the mist captured as described above accumulates in the groove, thereby preventing the mist from scattering into the pipe.

According to a fourth aspect of the present invention, a solvent vapor generated in a fixing step of an electrophotographic printing machine using a wet toner is led to a heat exchanger through a solvent vapor pipe, and the solvent is cooled in a cooling section of the heat exchanger. In a solvent recovery apparatus of an electrophotographic printing machine that cools steam and condenses and recovers a solvent, the heat exchanger connects the solvent vapor pipe to a space formed below the cooling unit. At least in the vicinity of the opening of the solvent vapor pipe in the space, a large number of gas-permeable turbulence promoters formed, for example, in a ring shape are accommodated.

Preferably, the heat exchanger is provided with a mesh such as a wire mesh at an upper portion and a lower portion of the space accommodating the turbulence promoting ring.

In the present invention, the turbulence promoter may be nylon, plastic, light metal, or the like.
A plastic material having high wettability to a solvent is preferable. The shape of the substantially ring-shaped turbulence promoting body (hereinafter referred to as a promoting ring) may be a simple shape such as a small cylindrical piece, a donut shape, or a perforated disk shape. A shape fixed radially from a portion has a large surface area and is suitable.

According to the invention, the solvent vapor flowing into the space of the heat exchanger through the solvent vapor pipe is turbulently promoted in a large number in the space divided into upper and lower spaces by a net state. By repeated collisions, turbulence is created and spreads in space. Accordingly, the solvent vapor is not deflected in the space, does not blow through the space, or stays in the space, but spreads over the entire flow path and flows into the cooling unit as a uniform flow. Thereby, the cooling effect in the cooling section of the heat exchanger is improved.

In particular, when the turbulence promoting ring is made of a plastic material having a high wettability, the condensate of the solvent uniformly wets the surface of the turbulence promoting ring, so that the solvent mist easily adheres. In addition, trapping of solvent mist is promoted.

According to a fifth aspect of the present invention, there is provided a combination of the first and fourth aspects. In addition to the fourth aspect, the solvent vapor pipe connected to the heat exchanger is provided at least at one position in the middle. To form a bellows-like tube made of aluminum material.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent.

FIG. 1 is an overall configuration diagram of a solvent recovery apparatus of an electrophotographic printing machine according to an embodiment of the present invention, and FIG.
FIG. 3 is a front view of the turbulence promoting ring, and FIG. 4 is a sectional view taken along line AA of FIG.

In FIG. 1, reference numeral 1 denotes an electrophotographic printing machine, which is configured as follows. 11 is a casing, 1
Reference numeral 2 denotes webs 13a and 13b, photosensitive drums, 14a denotes an intermediate fixing roller, 14b denotes a final fixing roller, and the web 1 is formed by the photosensitive drums 13a and 13b using wet toner.
2 is printed.

Then, the toner transferred to the web 12 by printing on the photosensitive drum 13a of the first stage passes through the web 12 through an intermediate fixing roller 14a maintained at 100 ° C. to 130 ° C. The toner transferred to the web 12 by printing on the second-stage photosensitive drum 13b is then
The web 12 is fixed by passing through a final fixing roller 14 b maintained at 20 ° C. to 150 ° C. The toner web 1 by the fixing rollers 14a and 14b
At the time of heat fixing to 2, the solvent in the toner evaporates and gasifies. As described above, the gasified solvent, that is, the solvent vapor, is sent to the heat exchanger 30 through the solvent vapor pipes 32 and 31 by the blowers 2a and 2b.

The configuration of the electrophotographic printing machine described above is the same as that of the prior art shown in FIG. In the present invention, the solvent vapor pipe and its attachment, and the heat exchange device are improved.

That is, 31 and 32 are solvent vapor tubes,
One solvent vapor pipe 32 connects a solvent vapor suction port 27a provided in a cover 26a for the intermediate fixing roller 14 of the electrophotographic printing machine 1 to a space 34 of a heat exchange device 30 described later. The other solvent vapor pipe 31 connects the solvent vapor suction port 27b provided in the cover 26b for the final fixing roller 14b of the printing machine 1 to a space 34 described later. 2a is a blower for conveying the solvent vapor provided in the solvent vapor pipe 32, and 2b is a blower for conveying the solvent vapor provided in the solvent vapor pipe 31.

The solvent vapor tubes 31 and 32 are made of an aluminum material (including an aluminum alloy) and are formed in a bellows shape as shown in FIG. In this case, the solvent vapor pipes 31 and 32 may be spirally continuous pipes or pipes formed by connecting ring pieces having a mountain-shaped cross section in the longitudinal direction.

The bellows-like solvent vapor pipes 31, 3
2 is a turning angle of 90 ° in at least one place in the middle
A curved tube portion 31a or 32a curved at a large bending angle of up to 180 ° is formed. Reference numeral 33 denotes a grounding means, which electrically grounds the solvent vapor pipes 31 and 32 at one point of each of the solvent vapor pipes 31 and 32.

Reference numeral 30 denotes a heat exchange device, and the heat exchange device 3
Reference numeral 0 denotes a vertical type, and a heat exchanger 3 is provided substantially at the center thereof. The heat exchanger 3 is connected to a cooler 4 by a refrigerant circulation line 10 as in the prior art shown in FIG. 5, and exchanges heat between a low-temperature refrigerant from the cooler 4 and a solvent vapor that has passed through a space described later. Thus, the solvent vapor is cooled.

In the heat exchanger 30, a heater 41 for heating the low-temperature gas from which the solvent has been separated in the heat exchanger 3 is provided above the heat exchanger 3. Also,
A blower 42 is provided above the heater 41 (outlet side) to generate an upward flow of gas or solvent vapor in the heat exchange device 30. 43 is a motor for driving the blower 42.

Reference numeral 34 denotes a space formed below the heat exchanger 3, and outlets of the solvent vapor pipes 31 and 32 are opened in the space 34 at the top and bottom. A large number of turbulence promoting rings 35 are accommodated in the space 34, and the accommodation range of the rings 35 is partitioned by upper and lower wire meshes 36,36.

FIGS. 3 and 4 show an example of the turbulence promoting ring 35, which is made of a synthetic resin material.
A plurality (eight in this example) of rings 35b are radially fixed to the outer periphery of a boss 35a having a hole 35c at the center. The turbulence promoting ring 35 can be made of a nylon material, a light metal material or the like, but a plastic material having high wettability to a solvent is preferable. In addition to the above, the shape of the ring 35 is preferably a donut shape, a perforated disk shape, or the like, but the shape may be arbitrary.

At the lower part (bottom part) of the heat exchanger 30,
The separated solvent 39 and water 40 are stored, and an oil / water separation surface sensor 37 is provided at both boundaries. 46 is a drain pipe connected to the bottom of the heat exchange device 30, and 38 is a water discharge valve for opening and closing the drain pipe 46. 9 is a solvent recovery tank,
9b is a solvent discharge pipe, and 9a is an on-off valve for opening and closing the solvent discharge pipe 9b.

In the solvent recovery apparatus for an electrophotographic printing machine using the wet toner having the above-described configuration, the toner web 1 is formed on the intermediate fixing roller 14a of the electrophotographic printing machine 1.
Solvent vapor generated during the fixing process to the fixing roller 2 is sucked into the solvent vapor pipe 32 from the suction port 27a provided in the cover 26a of the intermediate fixing roller 14a by the blower 2a.
The solvent vapor generated during the fixing step in the final fixing roller 14b is blown by the blower 2b.
Is sucked into the solvent vapor pipe 31 from a suction port 27b provided in the cover 26b.

The solvent vapor flows through the solvent vapor pipes 32 and 31, respectively, and is introduced into the space 34 of the heat exchanger 30. At the time of the flow of the solvent vapor, the solvent vapor pipes 31 and 32 have at least one or more bent pipe portions 31a and 32a which are bent greatly in a range of 90 ° to 180 °. The solvent vapor collides with the inner wall of the tube during the curved flow in the curved part, and turbulence is promoted, and the mist in the solvent vapor falls and is separated from the gas, so that the solvent mist in the solvent vapor is separated. Promoted.

Further, since the solvent vapor pipes 31 and 32 are formed in a bellows shape to form a flow path having a large pressure loss, the solvent vapor flowing through the solvent vapor pipes 31 and 32 protrudes into the pipes. The turbulence spreads by colliding with the mountain portion 032 of the inner wall surface, and turbulence is promoted. Thereby, the solvent mist in the solvent vapor falls, and the separation from the gas is promoted.

Since the solvent vapor pipes 31 and 32 are provided with a grounding means 33 on the way, the solvent vapor pipes 31 and 32 made of aluminum are grounded to a potential zero (zero) state. The solvent mist positively charged to the same potential as the positively charged toner is captured and adsorbed on the inner wall surfaces of the solvent vapor pipes 31 and 32 by electrostatic action.

As described above, the solvent vapor tubes 31 and 32
Since the solvent mist separated inside the pipes accumulates in the grooves 031 of the solvent vapor pipes 31 and 32 formed in a bellows shape, the solvent mist is prevented from scattering inside the pipes and is efficiently collected.

As described above, the solvent vapor pipe 31 for the solvent vapor
The mist separation action in the solvent vapor pipes 31 and 32 takes place over the entire length of the solvent vapor pipes 31 and 32, whereby the solvent vapor is reduced in the solvent concentration and introduced into the space 34 of the heat exchanger 30. Further, the separated solvent mist is formed in the lower part of the inner surface of the solvent vapor pipes 31 and 32 or in the groove
1 and flow down to the lower part of the space 34.

The solvent vapor whose solvent concentration has been reduced as described above is introduced into the space 34 of the heat exchanger 30 from the solvent vapor pipes 31 and 32. Then, the solvent vapor is subjected to a turbulent flow promoting action by a turbulent flow promoting ring 35 described later, and then is raised by the suction force of the blower 42 and guided to the heat exchanger 3.

In the heat exchanger 3, as in the prior art shown in FIG. 5, the solvent vapor is cooled by exchanging heat with a low-temperature refrigerant sent from the cooler 4, and the cooling condenses and liquefies the solvent. Then, it accumulates in the lower part of the heat exchange device 30 via the space 34. On the other hand, the low-temperature gas after the solvent is separated is heated in the heater 41,
After the temperature is raised to about (° C.), the gas is discharged to the outside through the exhaust port 44.

In the space 34, the solvent vapor flowing into the space 34 is turned into turbulent flow by repeatedly colliding with a turbulence promoting ring 35 accommodated in the space 34, and the turbulent flow into the space 34. spread. This causes the solvent vapor to drift in the space 34 and a part thereof
Heat exchanger 3
Solvent vapor does not flow uniformly into
The solvent vapor spreads over the entire flow path in the space 34 and becomes a uniform flow, so that the cooling effect in the heat exchanger 3 is improved.

If the turbulence promoting ring 35 is made of a plastic material having high wettability, the condensate of the solvent dropped from the heat exchanger 3 uniformly wets the surface of the turbulence promoting ring 35. In addition, the solvent mist easily adheres, and the capture of the solvent mist is promoted.

The solvent 39 that has passed through the space 34 and has passed through the wire mesh 36 accumulates in the lower part of the heat exchanger 30 and is recovered in the solvent recovery tank 9 through the solvent discharge pipe 9b. On the other hand, the moisture 40 in the air condensed in the heat exchange device 30 is:
The liquid 39 accumulates below the solvent 39 having a lower specific gravity, and the boundary surface is detected by the oil / water separation surface sensor 37 floating on the boundary surface between the two liquids. When the water content exceeds a predetermined amount, water is collected. The discharge valve 38 is opened, and the water is discharged.

[0048]

As described above, according to the first to third aspects of the present invention, the collision of the solvent vapor with the inner wall surface of the bellows-shaped solvent vapor pipe made of aluminum material causes the collision with the curved pipe portion. The separation of the solvent mist in the solvent vapor is promoted by the promotion of turbulence by the collision of the solvent vapor and the electrostatic action by the provision of the grounding means, and the solvent vapor having the reduced solvent concentration is sent to the heat exchanger. be able to. Thereby, even when the amount of the solvent is large after the fixing step, the separation of the solvent can be surely performed at the exit of the heat exchanger, the exhaust gas is free from the residual solvent, and the air pollution is prevented.

According to the invention of claims 4 and 5,
By providing a large number of turbulence promoting rings in the heat exchanger, the spread of the solvent vapor in the passage to the heat exchanger is obtained, and the solvent vapor to the heat exchanger becomes a uniform flow and is cooled in the heat exchanger. The effect is improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a solvent recovery device of an electrophotographic printing machine according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view (an enlarged view of a Z part in FIG. 1) of a solvent vapor pipe in the embodiment.

FIG. 3 is a plan view of a turbulence promoting ring in the embodiment.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is an overall configuration diagram of a solvent recovery device of an electrophotographic printing machine according to the related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic printing machine 2 a, 2 b blower 3 heat exchanger 4 cooler 9 solvent recovery tank 10 refrigerant circulation line 12 web 13 a, 13 b photosensitive drum 14 a intermediate fixing roller 14 b final fixing roller 26 a, 26 b cover 30 heat exchanger 31, 32 Solvent vapor pipes 31a, 32a Curved pipe part 031 Groove 33 Grounding means 34 Space 35 Turbulence promoting ring 36 Wire mesh 37 Oil / water separation surface sensor

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyoshi Kawamura 5007 Itozaki-cho, Mihara-shi, Hiroshima F-term in Mitsubishi Heavy Industries, Ltd. Mihara Works (reference) 2H027 ED08 ED25 ED30 JA01 JA07 JB14 JB20 JB22 JB30 JC08 JC20

Claims (6)

[Claims] 1. A solvent vapor generated in a fixing step of an electrophotographic printing machine using a wet toner is led to a heat exchanger through a solvent vapor pipe, and the solvent vapor is cooled by a cooling section of the heat exchanger. In a solvent recovery apparatus for an electrophotographic printer, wherein the solvent is condensed and recovered, the solvent vapor pipe is configured as a bellows-shaped pipe made of an aluminum material. . 2. The solvent recovery apparatus for an electrophotographic printing machine according to claim 1, wherein said solvent vapor pipe is formed in a curved pipe portion curved at least at one position. 3. The solvent recovery apparatus according to claim 1, wherein the solvent vapor pipe is electrically grounded. 4. A solvent vapor generated in a fixing step of an electrophotographic printing machine using a wet toner is led to a heat exchanger through a solvent vapor pipe, and the solvent vapor is cooled by a cooling section of the heat exchanger. In a solvent recovery device of an electrophotographic printing machine configured to condense and recover a solvent, the heat exchanger connects the solvent vapor pipe to an inlet-side space formed below the cooling unit, and Wherein a large number of turbulence promoters having air permeability are accommodated at least in the vicinity of the opening of the solvent vapor pipe. 5. The electrophotographic printing machine according to claim 4, wherein the solvent vapor pipe connected to the heat exchanger is formed in a bellows-like pipe made of an aluminum material by being bent at least at one point in the middle. Solvent recovery equipment. 6. The electrophotograph according to claim 4, wherein the heat exchanger is provided with a mesh such as a wire mesh at an upper portion and a lower portion of a space in which the turbulence promoting body is accommodated. Solvent recovery device for printing press.