JP2002296926A - Wet image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet image forming device where liquid developer adhering to a transfer member is prevented from adhering to an intermediate transfer body or transfer material again in secondary transfer. SOLUTION: When transfer paper is jammed or the secondary transfer is performed to the different-size transfer paper, the surface of a transfer roller 80 directly comes into contact with an intermediate transfer belt 60 and the liquid developer happens to adhere to the surface of the roller 80. Then, the liquid developer adhering to the surface of the roller 80 adheres to the belt 60 again or adheres to the back side of the transfer paper P in a next image forming stage. Therefore, the device is provided with an elastic blade 130 for cleaning the roller 80. The blade 130 follows minute ruggedness existing on the surface of the elastic layer on the roller 80 and removes the liquid developer in the ruggedness so as to secure excellent cleaness.

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, and more particularly, to a developer carrier for carrying a liquid developer in which toner is dispersed in a carrier liquid. The present invention relates to a wet image forming apparatus having an image carrier for carrying a developed image developed by a liquid developer carried on a developer carrier, and an intermediate transfer body for transferring a developed image on the image carrier.

[0002]

2. Description of the Related Art Conventionally, as a wet image forming apparatus of this type, a latent image on a latent image is developed with a liquid developer in which a toner is dispersed in an insulating liquid (hereinafter referred to as a "carrier liquid"). Then, a toner image formed by development is primary-transferred onto an intermediate transfer member, and then secondary-transferred onto a transfer material to obtain a final image.

[0003]

In the secondary transfer of the wet image forming apparatus, a transfer member is pressed against an intermediate transfer member to form a transfer nip, and a secondary transfer material is passed through the transfer nip. Transferring. The transfer member,
Only during the secondary transfer to the transfer material,
At other times, there is known a device provided with a contact / separation mechanism for separating from an intermediate transfer member. By providing the contact / separation mechanism, the adhesion of the liquid developer to the transfer member can be suppressed.

However, even in a wet image forming apparatus provided with the above-mentioned contact / separation mechanism, when a transfer material is jammed or when secondary transfer is performed to a transfer material having a different size, the transfer member directly contacts the surface of the intermediate transfer member. The liquid developer may come into contact with the transfer member and adhere to the transfer member. Then, the liquid developer adhered to the transfer member adheres again to the intermediate transfer belt, or adheres to the back side of the transfer material in the next image forming step, thereby soiling the transfer material.

The present invention has been made in view of the above background, and an object of the present invention is to prevent liquid developer adhered to a transfer member in secondary transfer from re-adhering to an intermediate transfer member or a transfer material. It is an object of the present invention to provide a wet image forming apparatus capable of performing the above-mentioned operations.

[0006]

In order to achieve the above object, the present invention is directed to a developer carrying member for carrying a liquid developer in which a toner is dispersed in a carrier liquid; An image carrier that carries a developed image developed by the carried liquid developer, an intermediate transfer body that primarily transfers a developed image on the image carrier, and a transferred image that is transferred onto the intermediate transfer body In a wet-type image forming apparatus having a secondary transfer unit that performs batch transfer to a material, the secondary transfer unit includes a transfer member and a cleaning member made of an elastic body that cleans a surface of the transfer member. Is what you do.

According to the first aspect of the present invention, even if the liquid developer adheres to the transfer member, the liquid developer adhered to the transfer member is cleaned by cleaning the transfer member with the cleaning member. Can be prevented from re-adhering to the intermediate transfer member or the transfer material. In addition, since the cleaning member made of an elastic body can follow fine irregularities on the surface of the transfer member, it is possible to remove the liquid developer that has entered the irregularities and secure good cleaning properties.

According to a second aspect of the present invention, in the wet image forming apparatus of the first aspect, a conductive elastic layer is provided on a surface portion of the transfer member, and the surface of the elastic layer is covered with a covering layer. It is characterized by a breaking elongation of 150 [%] or more, a tensile breaking strength of 200 [Kg / cm ² ] or more, and a 100% modulus of 150 [Kg / cm ² ] or less.

[0009] From the results of the repeated durability test, the elongation at break was 150% or more, and the tensile strength at break was 200 kg / c.
m ² ] or more and 100% modulus is 150 [Kg / c]
m ² ] or less, it is possible to prevent the occurrence of cracks in the coating layer. When a crack is generated in the coating layer, the liquid developer enters the crack and the cleaning performance is significantly reduced, or the cleaning cannot be performed. In the wet image forming apparatus of the present invention, the coating layer has a breaking elongation of 150 [%] or more, a tensile breaking strength of 200 [Kg / cm ² ] or more, and a 100% modulus of 150 [Kg / cm ² ]. cm ² ] or less, it is possible to prevent the occurrence of cracks in the coating layer even when repeatedly used, and to maintain the cleaning performance.

According to a third aspect of the present invention, in the wet image forming apparatus of the first or second aspect, the ten-point average roughness Rz (JIS) of the transfer member surface is 1 [μm] or less. Things.

The ten-point average roughness Rz (JI
If S) is more than 1 [μm], the unevenness of the surface becomes large, and the liquid developer easily enters the unevenness.
In the wet image forming apparatus according to the third aspect, the ten-point average roughness Rz (JIS) of the surface of the transfer member has a smoothness of 1 [μm] or less, and the liquid developer enters the unevenness on the surface. , And good cleaning performance by the cleaning member can be maintained.

According to a fourth aspect of the present invention, in the wet image forming apparatus of the first, second or third aspect, the surface energy of the transfer member is not more than 50 [dyn / cm].

The surface energy of the transfer member is 50 dyn
/ Cm], the wettability or hydrophilicity of the transfer member surface increases, and the liquid developer easily adheres to the surface. In the wet image forming apparatus according to the fourth aspect,
Since the surface energy of the transfer member is 50 dyn / cm or less, the wettability or hydrophilicity of the surface of the transfer member is small, and the adhesion of the liquid developer to the surface of the transfer member is reduced. It can contribute to maintaining sex.

The invention of claim 5 is the invention of claim 2, 3, or 4.
In the above wet image forming apparatus, the coating layer is formed using a resin tube.

In the wet image forming apparatus according to the fifth aspect, the elastic layer of the transfer member is covered with the resin tube,
As compared with the case where the elastic layer is coated by using a coating method, a dipping method, or the like, a coating layer having a smooth surface and a durable surface can be formed. Further, as compared with a coating method, a dipping method, or the like, the production is easy, so that the cost can be reduced.

According to a sixth aspect of the present invention, in the wet image forming apparatus of the fifth aspect, the thickness of the resin tube is 10 μm.
As described above, the thickness is 100 [μm] or less.

If the thickness of the resin tube is too thin than 10 [μm], processing is difficult and durability is lost. On the other hand, when the thickness of the resin tube is too large than 100 [μm], the hardness of the surface becomes high, the ability to follow the irregularities of the transfer material is deteriorated, and the adhesion is reduced. In the wet image forming apparatus according to the sixth aspect, since the thickness of the resin tube is not less than 10 [μm] and not more than 100 [μm], the processing is easy and durable, and the adhesion follows the irregularities of the transfer material. Can be obtained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color electrophotographic copying machine (hereinafter referred to as a color copying machine) which is a wet color image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram of the entire image forming apparatus according to the first embodiment of the present invention. This apparatus is provided with image forming units Bk, C, M, and Y for each color for forming a color image in a color image forming process. Each image forming unit includes a photoreceptor as an image carrier, an exposing device, a charging device, a cleaning device, a neutralizing lamp, a wet color developing device used in a color image forming process, and the like, which will be described later. In the present embodiment, the image forming units Bk are for black, C is for cyan, M is for magenta, and Y is for yellow. It is configured. Each of the photoconductors has a part of its peripheral surface exposed from an opening of the housing of each image forming unit, and is arranged to be rotatable in the direction of arrow A.

Around each photoreceptor, a charging device 20 and an exposure device (not shown) apply a laser beam 30
And a photoreceptor cleaning blade 50 as a photoreceptor cleaning means, and a color developing device 40 used in a color image forming process.

Each of the image forming units Bk, C, M,
On the side of Y, a plurality of stretching rollers are rotatably stretched in the direction of arrow B so as to be in contact with the peripheral surface of the exposed portion of each photoconductor, and a visible image formed on the surface of the photoconductor is transferred. An intermediate transfer belt 60 as an image carrier for carrying the image is provided. The intermediate transfer belt 60 is a belt in which conductive rubber in which carbon is dispersed is coated with a fluorine-based resin in order to improve the smoothness of the belt surface.

The tension roller 6 of the intermediate transfer belt 60
A cleaning roller 70 as a cleaning member of a cleaning device for cleaning the surface of the intermediate transfer belt 60 is disposed so as to abut on the surface of the intermediate transfer belt 60 so as to face the portion wound around 1a. A conductive roller to which a primary transfer bias for transferring (primary transfer) a visible image on each photoconductor 10 onto the intermediate transfer belt 60 is applied at a position facing each photoconductor 10 on the inner peripheral surface side of the belt. 11, 12, 13, 1
4 are provided.

The stretching roller 6 of the intermediate transfer belt 60
A transfer roller 80 is provided so as to face the portion wound around 1b. The transfer roller 80 is a conductive roller to which a secondary transfer bias for transferring (secondary transfer) the visible image on the intermediate transfer belt 60 to the transfer paper P is applied.

Each of the color developing devices 40 has substantially the same configuration, and has a high viscosity liquid developer of 100 to 10000 mPa · s (hereinafter referred to as a developer) in which each color toner is dispersed in a carrier liquid at a high concentration. And a developing roller 41 as a developer carrier provided in contact with the surface of the photoreceptor, and a lower portion immersed in the developer 18 in the developer tank. The developing roller 41 includes a coating roller 43 that applies the pumped developer to the developing roller 41 and a peeling blade 44 that removes the developing solution not used for development. In the present embodiment, silicone oil is used as the carrier liquid.

Next, the image forming operation of the color copying machine will be described. Since each image forming unit performs image formation based on the same principle, here, only the yellow image forming process on the photoconductor 10 located on the left end side in FIG. 1 will be described. The description of the image forming process on the body is omitted.

In FIG. 1, the photoreceptor 10 is uniformly charged by the electric charge from the charging device 20 while rotating in the direction of arrow A, and then a laser beam 30 modulated based on yellow image information from an exposure device (not shown). To form an electrostatic latent image on the surface. The yellow latent image formed on the photoreceptor 10 is developed by a yellow developer of a yellow developing unit 40, and a yellow toner image is formed on the photoreceptor.
The developing operation of the developing device will be described later.

The yellow toner image formed on the photoreceptor 10 is transferred onto an intermediate transfer belt 60 that rotates in the direction of arrow B in synchronization with the photoreceptor 10 by a predetermined primary transfer bias applied to the roller 11. You. On the other hand, the untransferred developer is removed from the photoreceptor 10 after the transfer by the photoreceptor cleaning blade 50 to prepare for the next color image formation.

The above steps are sequentially repeated for each of the single-color images of yellow, magenta, cyan, and black to form a superimposed full-color image on the intermediate transfer belt 60.

The full-color image superimposed on the intermediate transfer belt 60 is transferred onto a transfer sheet P as an object to be transferred conveyed from a sheet feeding unit (not shown) by a predetermined secondary transfer bias applied to the transfer roller 80. It is transferred all at once. After the transfer is completed, the transfer paper P is separated from the intermediate transfer belt 60, and after the excess carrier liquid on the transfer paper P is removed by the pre-fixing processing liquid removing roller 150, the transfer paper P is pressed against the fixing roller 91 of the fixing device 90. The fixing process is performed by the roller group 92, and the sheet is discharged outside the apparatus.

Next, the developing operation by the developing device 40 will be described. The application roller 43 draws up the developer 18 by rotation, and applies the developer 18 to the surface of the development roller 41. In this process, the developer 18 becomes a thin film, and a thin layer of the developer having a certain thickness is formed on the developing roller 41. The thin layer of the developing solution on the developing roller 41 is transported to a developing area where the photoconductor 10 and the developing roller 41 are in contact with each other by the rotation of the developing roller 41. Then, in the developing area, a developing bias is applied, and the developing roller 41 is peeled off from the developing roller 41 in a state of a thin layer, and moves to a portion of the photoconductor 10 where a latent image is formed. On the other hand, the developer not used for the development is removed by the peeling blade 44 and falls into the developer tank 42 by gravity.

Next, a description will be given of a configuration for cleaning the liquid developer adhering to the transfer roller 80, which is a feature of the present embodiment. FIG. 2 is a schematic configuration diagram in which an elastic blade 130 made of an elastic body for cleaning the transfer roller 80 is provided.

The transfer roller 80 has a structure in which a rubber elastic layer is provided on the outer peripheral surface of a metal core such as aluminum. A bias power supply (not shown) is connected to the transfer roller 80, and a bias voltage is applied to form a secondary transfer electric field between the transfer roller 80 and the intermediate transfer belt 60 to transfer the toner image on the intermediate transfer belt 60 to the transfer paper. Side to transfer. The transfer roller 80 comes into direct contact with the surface of the intermediate transfer belt 60 when the transfer paper is jammed or when secondary transfer is performed on transfer paper of a different size, and the liquid developer may adhere to the roller surface. . Then, the liquid developer adheres to the intermediate transfer belt 60 again, or adheres to the back side of the transfer paper P in the next image forming step, thereby soiling the transfer paper P. For this reason, an elastic blade 130 is provided to clean the liquid developer adhered to the transfer roller 80. The elastic blade 130,
Since fine irregularities existing on the surface of the elastic layer of the transfer roller 80 can be followed, the liquid developer that has entered the irregularities can be removed, and good cleaning performance can be ensured.

Incidentally, a coating layer for coating the elastic layer surface of the transfer roller 80 may be provided. According to the results of the repeated durability test, this coating layer had a breaking elongation of 150% or more and a tensile breaking strength of 200 kg / cm ² or more and 100% or more.
When the modulus is 150 [Kg / cm ² ] or less, generation of cracks can be prevented. If a crack occurs in the coating layer, the liquid developer enters into the crack, and the cleaning performance is significantly reduced, or cleaning cannot be performed.

The ten-point average roughness Rz (JIS) of the surface of the transfer roller 80 is configured to be 1 [μm] or less. The ten-point average roughness Rz of the surface of the transfer roller 80 is 1 [μ]
This is because if it is larger than m], the surface irregularities become large, and the liquid developer easily enters these irregularities.
FIG. 3 is a graph showing the cleaning property with respect to the surface roughness of the transfer roller 80. The smoother the surface, the higher the cleaning performance. On the other hand, when the smoothness of the surface decreases, the cleaning property also decreases. This is because the liquid developer enters the fine irregularities on the surface.

The transfer roller 80 has a surface energy of 50 [dyn / cm] or less. If the surface energy of the transfer roller 80 is too large than 50 [dyn / cm], the wettability or hydrophilicity of the roller surface increases, and the liquid developer easily adheres to the roller surface.

Further, the coating layer of the transfer roller 80 can be formed using a resin tube. By coating the surface of the elastic layer of the transfer roller 80 with a resin tube, compared to the case of coating using a coating method or a dipping method,
A durable coating layer having a smooth surface can be formed. The thickness of the resin tube, which is easier to manufacture than the coating method or the dipping method and can reduce the cost, is in the range of 10 μm or more and 100 μm or less. The thickness of the resin tube is 10μ
If the thickness is too thin, processing is difficult and durability is lost. On the other hand, when the thickness of the resin tube is 100
If the thickness is more than [μm], the hardness of the surface is increased, the ability to follow the irregularities of the transfer material is deteriorated, and the adhesion is reduced.

[0036]

According to the first to sixth aspects of the present invention, by cleaning the transfer member with the cleaning member,
There is an excellent effect that the liquid developer adhered to the transfer member can be prevented from re-adhering to the intermediate transfer body or the transfer material. Further, by using a cleaning member made of an elastic body, there is also an excellent effect that the liquid developer that has entered fine irregularities on the surface of the transfer member can be removed and good cleaning properties can be secured.

In particular, according to the second aspect of the present invention, there is an excellent effect that a crack is prevented from being generated in the coating layer even when the coating layer is repeatedly used, and the cleaning performance can be maintained.

In particular, according to the invention of claim 3, the ten-point average roughness Rz (JIS) of the surface of the transfer member has a smoothness of 1 [μm] or less, and the unevenness of the surface of the liquid developer Has an excellent effect that it is possible to prevent the infiltration of water and maintain good cleaning properties.

In particular, according to the invention of claim 4, since the surface energy of the transfer member is 50 dyn / cm or less, the wettability or hydrophilicity of the surface of the transfer member is small,
There is an excellent effect that the adhesion of the liquid developer to the surface of the transfer member is reduced, and it is possible to contribute to maintaining good cleaning performance.

Particularly, according to the fifth aspect of the present invention, it is possible to form a durable coating layer having a smooth surface as compared with the case where the elastic layer is coated using a coating method or a dipping method. Has an effect. Further, compared to the coating method, the dipping method, and the like, there is an excellent effect that the production can be easily performed and the cost can be reduced.

In particular, according to the invention of claim 6, since the thickness of the resin tube is not less than 10 [μm] and not more than 100 [μm], processing is easy and durable, and it follows irregularities of the transfer material. There is an excellent effect that it is possible to have a surface hardness of such a degree that the adhesiveness can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a color copying machine according to an embodiment.

FIG. 2 shows a transfer roller 8 of the color copying machine according to the embodiment.
FIG. 4 is a schematic configuration diagram in which an elastic blade 130 made of an elastic body for cleaning 0 is provided.

FIG. 3 is a graph showing a cleaning property with respect to a surface roughness of a transfer roller.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor 18 developing solution 20 charging device 30 laser beam 40 developing device 41 developing roller 42 developing solution tank 43 application roller 44 peeling blade 50 photoconductor cleaning blade 60 intermediate transfer belt 61 tension roller 70 cleaning roller 80 transfer roller 90 fixing device Reference Signs List 91 fixing roller 92 pressing roller group 100 liquid removing roller 110 bias power supply 130 elastic blade 150 liquid removing roller before fixing processing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H074 AA03 BB02 BB08 BB42 BB50 EE07 2H200 FA08 GA12 GA43 GA47 GA52 GB12 GB43 HA03 HA12 HB03 HB12 HB22 JA02 JA23 JA25 JA26 JA27 JA28 JC03 JC12 LB02 LB08 LB09 MC11 MA13 MB13 MC06 NA01

Claims (6)

[Claims] A developer carrying member for carrying a liquid developer in which toner is dispersed in a carrier liquid; an image carrying member for carrying a visible image developed by the liquid developer carried on the developer carrying member; An intermediate transfer member that primarily transfers a visual image on the image carrier;
A wet image forming apparatus comprising: a secondary transfer unit that collectively transfers a visual image transferred onto the intermediate transfer body to a transfer material;
A wet image forming apparatus, wherein the secondary transfer means has a transfer member and a cleaning member made of an elastic body for cleaning the surface of the transfer member. 2. The wet image forming apparatus according to claim 1, wherein a conductive elastic layer is provided on the surface of the transfer member, and the surface of the elastic layer is covered with a coating layer.
[%] Or more and tensile breaking strength is 200 [Kg / c]
m ² ] or more, and the 100% modulus is 150 [Kg /
cm ² ] or less. 3. The wet-type image forming apparatus according to claim 1, wherein the surface of the transfer member has a ten-point average roughness Rz (JIS).
Is 1 [μm] or less. 4. The wet image forming apparatus according to claim 1, wherein the transfer member has a surface energy of 50 dyn.
/ Cm] or less. 5. A wet image forming apparatus according to claim 2, wherein said coating layer is formed using a resin tube. 6. A wet image forming apparatus according to claim 5, wherein said resin tube has a thickness of 10 μm or more and 100 μm or more.
A wet image forming apparatus characterized by the following.