KR20060033371A - Transfer unit and wet-type image forming apparatus having the same - Google Patents

Abstract

The transfer unit of the wet image forming apparatus according to the present invention comprises: an intermediate transfer member on which a visible image is formed by a liquid developer in which a toner and a carrier are mixed; A secondary transcript circumscribed with the intermediate transcript and receiving a visible image from the intermediate transcript; In order to prevent the carrier on the side of the intermediate transcript from being transferred to the secondary transcript when the visible image is transferred from the intermediate transcript to the secondary transcript, a second carrier having affinity with the carrier and not being mixed with the carrier may be used. A second carrier supply unit for supplying a secondary transfer member; And a tertiary transfer member which is external to the secondary transfer member and finally transfers a visible image to a print medium. According to this, there are almost no harmful carrier components in the print medium to which the final image has been transferred. Therefore, the size of the oxidation catalyst unit for treating the carrier vapor can be reduced in size, and power consumption can be reduced.

Liquid, developer, carrier, organic, removal, toner, liquid, wet, carrier, VOC

Description

Transfer unit and wet image forming apparatus having same {TRANSFER UNIT AND WET-TYPE IMAGE FORMING APPARATUS HAVING THE SAME}

1 is a view schematically showing a general wet image forming apparatus;

2 is a view schematically showing a transfer unit and a wet image forming apparatus having the same according to an embodiment of the present invention;

3 is a view showing for explaining the transfer operation of the transfer unit according to an embodiment of the present invention, and

4A, 4B and 4C are views for explaining the role of the second carrier in the transfer unit shown in FIG.

<Description of Symbols for Main Parts of Drawings>

100; imaging unit 110; photosensitive member

120; Developing unit 200; Intermediate transcript

210,220,230; belt support roller 300; secondary transfer member

400; second carrier supply unit 500; tertiary transfer member

600; fixation unit 700; oxidation catalyst unit

C1; first carrier C2; second carrier

The present invention relates to a wet image forming apparatus using a liquid developer, and more particularly, to a transfer unit having an improved structure for transferring an image onto a print medium and a wet image forming apparatus having the same.

As is well known, the wet image forming apparatus uses a liquid developer in which a toner and a carrier are mixed. Norpar is mainly used as the carrier, which is a solvent of a hydrocarbon system which is a mixture of C ₁₀ H ₂₂ , C ₁₁ H ₂₄ , C ₁₂ H ₂₆ , and C ₁₃ H ₂₈ .

The visible image by the developer formed on the photosensitive member is superimposed on the intermediate transfer member and transferred to the print medium by the intermediate transfer member. When the print medium on which the visible image is transferred passes through the fixing unit, the toner in the visible image is fixed to the print medium, and the carrier is evaporated with a flammable hydrocarbon gas such as methane (CH ₄ ) and discharged to the outside.

On the other hand, flammable hydrocarbon gas is classified as a volatile organic compound (VOC), and when discharged as it is, it pollutes the surrounding environment and emits an unpleasant odor. For this reason, the above-described apparatus for purifying flammable hydrocarbon gas is employed as the wet image forming apparatus.

1 is a schematic view of a wet image forming apparatus having an oxidation catalyst unit for removing hydrocarbon gas generated from a carrier using a catalyst filter.

In the drawings, reference numeral 10 is an image forming unit, 20 is an intermediate transfer belt, 30 is a secondary transfer roller, 40 is a fixing unit, and 50 is an oxidation catalyst unit.

The image forming unit 10 includes a photosensitive member 11 on which an electrostatic latent image is formed, and a developing unit 12 for developing a visible image by developing an electrostatic latent image of the photosensitive member 11 with a liquid developer mixed with a toner and a carrier. do. The photosensitive member 11 and the developing unit 12 are provided in four colors (yellow, magenta, cyan and black) to form a color image.

The intermediate transfer belt 20 is provided to circumferentially orbitally move with each photosensitive member 11. In the drawings, reference numerals 21 and 22 denote rollers for supporting the intermediate transfer belt 20, and reference numeral 23 denotes a voltage applying unit. The visible image formed on the photosensitive member 11 is superimposed on the intermediate transfer belt 20 to realize a full color image.

The secondary transfer roller 30 is installed so as to be external to the intermediate transfer belt 20 so that the visible image of the intermediate transfer belt 20 is transferred to the print medium P interposed therebetween. The secondary transfer roller 30 is grounded 31. The print medium P is picked up from a paper feed cassette (not shown) and fed to a transfer nip between the secondary transfer roller 30 and the intermediate transfer belt 20 by a transfer roller or the like.

The fixing unit 40 includes a heating roller 41 and a pressure roller 42. The fixing unit 40 applies heat and pressure to the printing medium P on which the image is transferred to fix the image on the printing medium P.

The oxidation catalyst unit 50 serves to purify the carrier vapor generated in the fixing process with a harmless gas and discharge it to the outside. The oxidation catalyst unit 50 includes an exhaust duct 51, a fan 52, a catalyst filter 53, and the like.

However, in the general wet image forming apparatus as described above, not only the toner in the developer but also the carrier are transferred to the print medium P through the secondary transfer roller 30 in the transfer process. The carrier is moistened, and therefore, a large amount of carrier vapor is generated in the fixing process, so that the size of the oxidation catalyst unit 50 for treating this cannot be avoided.

The present invention has been made in view of the above, and an object thereof is to provide a transfer unit of a wet image forming apparatus capable of maximally suppressing carrier movement to a print medium during a transfer process.

Another object of the present invention is to provide a wet image forming apparatus which is eco-friendly, small in size, and employs a low power type oxidation catalyst unit by providing a transfer unit having the above characteristics.

The transfer unit of the wet image forming apparatus according to the present invention for achieving the above object is an intermediate transfer body in which a visible image is formed by a liquid developer in which a toner and a carrier are mixed, and the intermediate transfer body is circumscribed with the intermediate transfer body. In order to prevent the carrier on the side of the intermediate transcript from being transferred to the secondary transcript when the visible image is transferred from the intermediate transcript to the secondary transcript from the intermediate transcript to the secondary transcript, the carrier is not mixed with the carrier. And a second carrier supply unit for supplying a second carrier having a property not to the secondary transfer member.

According to a preferred embodiment of the present invention, the transfer unit of the wet image forming apparatus includes a transfer belt as the intermediate transfer member, a transfer roller as the secondary transfer member, and a print medium arranged to be external to the secondary transfer roller. And a tertiary transfer roller for transferring a visible image of the secondary transfer roller.

Here, the second carrier supply unit is configured to include a roller which is disposed to circumscribe the secondary transfer member to bury the second carrier thinly on the secondary transfer member, but is not necessarily limited thereto. The supply unit may be of a spray structure for injecting a second carrier, or may be of a structure in which a part of the secondary transfer member is immersed in a container containing the second carrier.

In addition, the second carrier is suitable for water, in particular distilled water that does not conduct electricity, but is not necessarily limited thereto, and may be any material that does not mix well like water and oil and is well separated.

On the other hand, a wet image forming apparatus for achieving the object of the present invention, a developing unit for developing a visible image by developing at least one photosensitive member on which the electrostatic latent image is formed and the electrostatic latent image of the photosensitive member with a liquid developer mixed with a toner and a carrier An image forming unit having a; An intermediate transfer belt circumscribed with the photoreceptor to move in an endless orbit, and receiving a visible image superimposed from the photoreceptor; A secondary transfer roller circumscribed with the intermediate transfer belt and receiving a visible image from the intermediate transfer belt; In order to prevent the carrier on the side of the intermediate transfer belt from being transferred to the secondary transfer roller when the visible image of the secondary transfer roller is transferred from the intermediate transfer belt, a second carrier having an affinity with the carrier and not being mixed is used. A second carrier feed roller which supplies the secondary transfer roller; A tertiary transfer roller arranged to circumscribe the secondary transfer roller to transfer a visible image of the secondary transfer roller to a print medium; A fixing unit applying heat and pressure to the print medium to which the visible image is transferred to fix the image to the print medium; And an oxidation catalyst unit for purifying the carrier vapor generated in the fixing process and discharging it to the outside.

Best Mode for Carrying Out the Invention Preferred embodiments of the present invention will now be described based on the accompanying drawings.

2 is a view schematically showing a wet image forming apparatus employing a transfer unit according to an embodiment of the present invention, wherein reference numeral 100 denotes an image forming unit, 200 denotes an intermediate transfer member, 300 denotes a secondary transfer member, 400 is a second carrier supply unit, 500 is a tertiary transfer member, 600 is a fixing unit, and 700 is an oxidation catalyst unit.

As illustrated, the image forming unit 100 may mix a plurality of photosensitive members 110 having electrostatic latent images for each color (yellow, magenta, cyan, black) and the electrostatic latent images of the photosensitive member 110 with a toner and a carrier. And a developing unit 120 for developing with a liquid developer to form a visible image.

The intermediate transfer member 200 is disposed to circumscribe the photosensitive member 110. The visible image formed on the photosensitive member 100 is superimposed on the intermediate transfer member 200, whereby a full color image is realized on the intermediate transfer member 200.

The intermediate transfer member 200 is configured in the form of a belt as shown in the example, but is not necessarily limited thereto, as shown in Figure 3, may be configured in the form of a roller. When the belt is configured in the form of a belt, the first to third rollers 210, 220, 230 are supported by the caterpillar motion as shown. In addition, the provisional part 221 which is a voltage is connected to the 2nd roller 220 among the said rollers. Reference numeral 240 is a cleaning roller.

The secondary transfer member 300 is disposed to circumscribe the intermediate transfer member 200 and receives an image from the intermediate transfer member 200. The second transfer member 300 may be configured in the form of a roller, but the shape of the second transfer member 300 may not be particularly limited. The secondary transfer member 300 is grounded 310.

As shown in FIG. 3, the second carrier supply unit 400 may include a carrier C1 on the side of the intermediate transfer member 200 when the visible image is transferred from the intermediate transfer member 200 to the secondary transfer member 300. In order to prevent)) from moving to the secondary transfer member 300, a second carrier C2 having a property of being incompatible with the carrier C1 and not being mixed is supplied to the secondary transfer member 300. . In FIG. 3, T is a toner.

The second carrier supply unit 400 is disposed so as to circumscribe the secondary transfer member 300, and is formed of a roller that thinly covers the second carrier C2 on the outer circumference of the secondary transfer member 300. Here, the roller is formed of a material that is compatible with the second carrier C2 and spreads well. In addition, the second carrier supply unit 400 may be configured in a spray structure in which the second carrier is sprayed onto the secondary transfer member 300 in addition to the roller shape, and is thinly coated, and the second carrier C2 may be formed. As long as a part of the secondary transfer member 300 may be configured to be immersed in the container, the second carrier may be thinly applied to the secondary transfer member 300.

Here, the carrier C1 mixed with the existing developer is not an environmentally friendly material, and if it remains on the paper, the carrier C1 adversely affects the image quality. Therefore, the carrier C1 should not be transmitted to the print medium if possible.

On the other hand, the second carrier (C2) is a material that does not have affinity with the carrier (C1) is separated well, and should be selected as a material that does not cause a problem in the process of removing on the print medium. Substances such as water that do not cause environmental problems when evaporated by heat, among them, distilled water, which does not conduct electricity, are most suitable. In addition, it can be used as the second carrier (C2) as long as it is a substance that does not have affinity with the carrier (C1) in the developer containing the oil component.

The tertiary transfer member 500 is configured in the form of a roller, and is arranged to circumscribe the secondary transfer member 300. When the print medium P enters between the tertiary transfer member 500 and the secondary transfer member 300, the visible image of the secondary transfer member 300 is transferred to the print medium P. At this time, the components of the visible image present in the secondary transfer member 300 are mostly toner, and are a little harmless second carrier C2. Therefore, the image is transferred to the print medium P together with a small amount of harmless second carriers.

The print medium P is picked up from a paper feed cassette (not shown) and transferred to a transfer nip between the tertiary transfer member 500 and the secondary transfer member 300 by a transfer roller or the like.

The fixing unit 600 is disposed downstream of the print medium transport direction of the tertiary transfer member 500 and includes a heating roller 610 and a pressure roller 620. The print medium P on which the visible image is transferred is fixed to the print medium P by heat and pressure while passing through the fixing unit 600. In the fixing process, a small amount of the harmless second carrier C2 moistened in the print medium P by heating is evaporated and vaporized.

On the other hand, the oxidation catalyst unit 700 purifies the carrier vapor generated in the fixing process again and discharged to the outside as a completely harmless gas. At this time, since the generated carrier vapor is not only a small amount but also a harmful component, the oxidation catalyst unit 700 can be miniaturized and power consumption can be greatly reduced. The oxidation catalyst unit 700 includes an exhaust duct 710, a fan 720, a catalyst filter 730, and the like, as is generally the case.

Hereinafter, the transfer process of the transfer unit of the wet image forming apparatus according to the present invention will be described in detail with reference to FIGS. 3, 4A, 4B, and 4C.

In the intermediate transfer member 200, a visible image by a developer in which the toner T and the first carrier C1 are mixed is transferred from the photosensitive member. Then, the second carrier C2 is buried in the secondary transfer member 300 on the outer circumferential surface thereof by a second carrier supply unit 400 to a predetermined thickness.

In this state, when a voltage is applied so that electrostatic transfer is performed, as shown in FIG. 4B, the toner T on the intermediate transfer member 200 crosses the first carrier C1 and the second carrier C2 and is transferred to the second carrier. It is transferred to the surface of the dead body (300). At this time, since the first carrier C1 is not compatible with the second carrier C2 and is well separated, the first carrier C1 does not cross over to the secondary transfer member 300 and remains in the intermediate transfer member 200. As such, the visible image by the toner moved to the secondary transfer member 300 is finally transferred to the print medium, so that there are almost no harmful first carriers on the print medium.

Of course, at this time, the first carrier contained in the toner can be transferred, but the amount thereof is very small, and since the second carrier moved from the secondary transfer member 300 to the print medium is harmless, its processing is very easy. Do.

According to the present invention as described above, it is possible to provide an environment-friendly wet image forming apparatus with a small amount of harmful carrier vapor generated as a peripheral pollution source, and also it is possible to employ a small size and low power type oxidation catalyst unit to reduce costs We can plan.

While the invention has been shown and described in connection with the preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (5)

An intermediate transfer member on which a visible image is formed by a liquid developer in which a toner and a carrier are mixed; And a secondary transfer body circumscribed with the intermediate transfer body and receiving a visible image from the intermediate transfer body. In order to prevent the carrier on the side of the intermediate transcript from being transferred to the secondary transcript when the visible image is transferred from the intermediate transcript to the secondary transcript, a second carrier having affinity with the carrier and not being mixed with the carrier may be used. And a second carrier supply unit for supplying the secondary transfer member. The method of claim 1, The intermediate transfer member is composed of a belt, and the secondary transfer member which is external to the intermediate transfer belt is composed of a roller. And a tertiary transfer roller arranged to circumscribe the secondary transfer roller to transfer a visible image of the secondary transfer roller onto a print medium. The method according to claim 1 or 2, And the second carrier supply unit is disposed to circumscribe the secondary transfer member and includes a roller to thinly bury the second carrier on the secondary transfer member. The method of claim 3, wherein The transfer unit of the wet image forming apparatus, characterized in that the second carrier uses water. An image forming unit including at least one photosensitive member on which an electrostatic latent image is formed, and a developing unit which forms a visible image by developing the electrostatic latent image of the photosensitive member with a liquid developer mixed with a toner and a carrier; An intermediate transfer belt circumscribed with the photoreceptor to move in an endless orbit, and receiving a visible image superimposed from the photoreceptor; A secondary transfer roller circumscribed with the intermediate transfer belt and receiving a visible image from the intermediate transfer belt; In order to prevent the carrier on the side of the intermediate transfer belt from being transferred to the secondary transfer roller when the visible image of the secondary transfer roller is transferred from the intermediate transfer belt, a second carrier having an affinity with the carrier and not being mixed is used. A second carrier feed roller which supplies the secondary transfer roller; A tertiary transfer roller arranged to circumscribe the secondary transfer roller to transfer a visible image of the secondary transfer roller to a print medium; A fixing unit applying heat and pressure to the print medium to which the visible image is transferred to fix the image to the print medium; And And an oxidation catalyst unit for purifying the carrier vapor generated in the fixing process and discharging it to the outside.

Images