JP2002091215A - Image fixing device and method therefor, and image forming device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image fixing device capable of preventing scorch of a high resistance part on these roller while making fixing property improved by making the current to flow between a heating roller and pressing roller through recording paper. SOLUTION: This image fixing device is made so as to let the current flow between both conductive parts, by respectively disposing conductive parts 101a and 102a, and high resisting parts 101b and 102b, on the heating roller 101 and the pressing roller 102 to make the width W1 of the high resisting part 101b on the heating roller wider than the contact width W2 of either high resisting part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system, an ink jet system, a printing plate system or the like using a colored liquid containing a liquid carrier and chargeable colored particles. The present invention relates to an image fixing device, an image fixing method, an image forming apparatus, and an image forming method for fixing an image on a recording member on which an image formed of a contained colored liquid is formed.

[0002]

2. Description of the Related Art Conventionally, in this type of image fixing device,
There is known a surface moving body including a heating roller and a pressing roller that rotate while their surfaces are in contact with each other. At least one of these rollers has an elastic portion on its peripheral surface, and is freely deformed in a contact area with the other roller to increase the adhesion between the two rollers. Both rollers sandwich the recording member between the contact portions so that the image forming surface of the recording member such as recording paper contacts the heating roller. Then, the colored particles in the colored liquid constituting the image on the recording member are pressed by both rollers while being heated by the heating roller, and are fixed on the recording member.

In the image fixing apparatus having such a configuration, the liquid carrier in the colored liquid reduces the adhesion between colored particles such as toner and between the colored particles and the recording member, thereby deteriorating the fixing performance. .

[0004]

Therefore, the present inventor has proposed:
An image fixing device as shown in FIGS. 1A and 1B is under development. In these figures, the image fixing device 100
Has a heating roller 101 and a pressing roller 102 as two surface moving bodies. The heating roller 101 includes a conductive portion 101a made of a material having a relatively low electrical resistivity such as a metal material, and a high-resistance portion 101b made of an elastic member having a relatively high electrical resistivity fixed thereon. It has a halogen lamp 101c as a heating means disposed inside the conductive portion 101a. The pressing roller 102
Has a conductive portion 102a made of a material having a relatively low electrical resistivity such as a metal material, and a high-resistance portion 102b made of an elastic member having a relatively high electrical resistivity fixed thereon. I have. The conductive portion 101a of the heating roller 101 is electrically grounded, and a power supply 103 for outputting a fixing bias having a predetermined polarity is connected to the conductive portion 102a of the pressing roller 102.

[0005] The heating roller 101 and the pressing roller 102 are respectively connected to the high resistance portions 101b, 102b.
b, and rotates in the forward direction while forming a fixing nip.

The high resistance portion 101b of the heating roller 101
Is desirably formed as thin as possible as shown in the figure. By forming the high-resistance portion 101b having a lower electric conductivity than the conductive portion made of metal or the like to be thin,
This is because the warm-up time until the entire heating roller 101 is heated to the predetermined fixing temperature by the halogen lamp 101c can be shortened. Further, it is also possible to stabilize the temperature of the heating roller 101 during continuous fixing in which the fixing process is continuously performed on the plurality of recording papers 200.

On the other hand, it is desirable that the high resistance portion 102b of the pressing roller 102 be formed thick as shown. This is because, by forming the high resistance portion 102b thickly and deforming it more freely, the fixing nip region can be further widened and the fixing time can be secured longer.

An image 2 composed of a colored liquid containing a liquid carrier such as polysiloxane oil and a toner that is a chargeable colored particle is provided on a recording paper 200 as a recording member.
01 is formed. The recording paper 200 is transferred to the heating roller 101 and the pressing roller 10 by conveying means (not shown).
2 and is sandwiched between the two rollers while the image forming surface thereof is in contact with the heating roller 101.

In the image fixing apparatus 100 having such a configuration, when the fixing bias is output from the power source 103 to the conductive portion 102a, the heating roller 10
A current flows between the pressure roller 1 and the pressure roller 102. When the current is supplied in this way, it is possible to electrically move the charged toner in the colored liquid constituting the image 201 toward the surface of the recording paper 200. By this movement, the adhesive force between the toners and the adhesive force between the toner and the recording paper 200 are increased, so that the fixing performance can be improved.

However, when a fixing test was performed with the illustrated image fixing apparatus 100, a problem occurred in that the high resistance portion 101b of the heating roller 101 and the high resistance portion 102b of the pressing roller 102 were locally scorched. Was. As shown in FIG. 2 and FIG.
Alternatively, an image fixing apparatus 100 having a high resistance portion (101b or 102b) provided only on the pressing roller was also trial manufactured, but also in these devices, a problem that local scorching occurred in the high resistance portion occurred.

These problems are not limited to those in which the rollers (101, 102) are used as the two surface moving members as in the image fixing device 100 shown in each figure.
This may also occur in an image fixing apparatus in which a member other than a roller such as an endless belt is used for both or one of the surface moving members.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the object of the present invention through a recording member.
By providing an image fixing device, an image fixing method, an image forming device, and an image forming method, in which a current flows between two surface moving bodies to improve fixing performance, and can also prevent scorching of a high-resistance portion. is there.

[0013]

In order to achieve the above object, the invention according to claim 1 comprises two surface moving bodies for moving the surfaces while contacting each other, wherein the liquid carrier and the chargeable colored particles are separated. In an image fixing apparatus in which a recording member on which an image is formed by a contained colored liquid is sandwiched between both surface moving bodies to fix the image to the recording member, a conductive portion made of a conductive material, A conductive high-resistance portion fixed to the conductive portion so as to be in contact with the other surface moving body is provided on both surface moving bodies, and is sandwiched between the both surface moving bodies. The width of the high-resistance portion of the recording member that comes into contact with the image is set to be equal to or greater than the contact width of the two high-resistance portions, and a potential difference is generated between the conductive portions of the two surface moving members. Provide potential difference generating means It is characterized in.

In this image fixing device, the "width of the high resistance portion" indicates the length of the high resistance portion in a direction orthogonal to the moving direction of the surface moving body. The “contact width” indicates a contact length between the two high resistance portions in a direction orthogonal to the moving direction of the surface moving body. In this image fixing device, when a potential difference is generated between the conductive parts of both surface moving bodies, a current flows from the conductive part of one surface moving body to the conductive high-resistance part of the surface moving body, a recording member, It flows to the conductive part of this surface moving body via the conductive high resistance part of the other surface moving body. Therefore, it is possible to improve the fixing performance by flowing a current between the two surface moving members via the recording member.
Further, similarly to the image fixing device 100 shown in FIGS. 1A and 1B, a high-resistance portion is provided on both surface moving bodies. In such a configuration, if an elastic material is used for the high-resistance portion, both surface moving members may be constituted only by conductive portions made of a metal material or the like, or as in the case of the image fixing device 100 previously shown in FIGS. As compared with the case where the high-resistance portion is provided only on one of the surface moving bodies, it is possible to enhance the adhesion between the two surface moving bodies and improve the fixing performance. In addition, for the reasons described below, scorching of the high resistance portion can be suppressed, and the fixing efficiency can be improved.

That is, the inventor of the present invention has shown in FIGS. 1 (a) and 1 (b)
In the image fixing device 100 shown in FIG.
The cause of burning of b and 102b was examined in detail. Then, in the image fixing device 100, it has been found that the current flows intensively at the edge of the high resistance portion 101b of the heating roller 101. Specifically, in the image fixing device 100, as shown in FIG.
01, an exposed portion of the conductive portion 101a made of a metal material;
An electric field having a plurality of lines of electric force connecting the exposed portion of the conductive portion 102a made of a metal material of the pressing roller 102 is formed near both ends of both rollers. The plurality of lines of electric force in these electric fields are concentrated near both ends inside the high-resistance portion 102b of the pressing roller 102 as shown in the drawing, so that current is concentrated on the edge portion of the high-resistance portion 101b of the heating roller 101. I understand. When the current is concentrated on the edge portion of the high resistance portion 101b of the heating roller 101, the pressing roller 10 that comes into contact with the edge portion or the edge portion.
One high-resistance portion 102b excessively generates heat. In addition, the discharge easily occurs between the conductive portion 101a and the high-resistance portion 102a of the pressing roller 102 beyond the edge portion. In the image fixing device 100 shown in FIG. 1, the edge portion of the high resistance portion 101 b of the heating roller 101 or the pressing roller
The 02 high-resistance portion 102b was scorched. In addition, since the current flows intensively at the edge of the high resistance portion 101b of the heating roller 101, the current flowing through the recording paper 200 (fixing width W3) is smaller than when the current flows uniformly over the entire contact area between the two rollers. The transfer amount was reduced and transfer efficiency became poor. In the image fixing apparatus 100 shown in FIG. 1, a negative fixing bias is supplied to the pressing roller 102 so that the positive toner is applied to the pressing roller 102.
However, the same problem can be solved even when the fixing roller is supplied with a positive fixing bias to the heating roller 101 to move the positive toner to the pressing roller 102 side. Occurs. Further, a positive fixing bias may be supplied to the pressing roller 102 or the heating roller 101 may be used.
However, even if the negative polarity toner is supplied to the pressing roller 102 by supplying a negative fixing bias to the pressing roller 102, only the direction of the current or the discharge is reversed, and the high resistance portion of the heating roller 101 is formed. The current is still concentrated on the edge portion of 101b.

Therefore, in the present image fixing device, the width of the high-resistance portion of the surface moving body that contacts the image of the recording member, such as a heating roller, is set to be equal to or greater than the contact width of the high-resistance portion of both surface moving bodies. . If such a configuration is described using an example using a heating roller and a pressing roller, the configuration is as shown in FIGS. 5 and 6, for example. In FIG. 5, the heating roller 101
The width W1 of the high resistance portion 101b is equal to the contact width W of the two high resistance portions.
It is the same size as 2. In FIG. 6,
The width W1 is larger than the contact width W2.
When the width W1 is equal to or larger than the contact width W2, the lines of electric force are less likely to concentrate near both ends inside the high resistance portion 102b of the pressing roller 102 as shown in FIG. As shown in FIG. 6, since the lines of electric force do not pass through the inside of the high resistance portion 102b, the current concentration on the edge portion of the high resistance portion 101b of the heating roller 101 can be suppressed or the current concentration can be reduced. It does not happen. As a result, both high resistance portions 101b, 10b
Burning of 2b is suppressed, and fixing efficiency is improved.

According to a second aspect of the present invention, in the image fixing device of the first aspect, the width of the high resistance portion in the surface moving body that comes into contact with the image is larger than the contact width. Things.

In this image fixing device, as in the image fixing device 100 previously shown in FIG. 6, the exposed portion of the conductive portion of the surface moving body which does not contact the image and the exposed portion of the surface moving body which does not contact the image. Lines of electric force formed between the exposed portions of the conductive portion do not pass through the inside of the high resistance portion in the former surface moving body. Therefore, as compared with the image fixing apparatus shown in FIG. 5 in which the width W1 is set to be the same as the contact width W2 and the lines of electric force are hardly concentrated, the high resistance of the both-surface moving body is more excellent. It is possible to suppress scorching of the portion and improve the fixing efficiency.

According to a third aspect of the present invention, in the image fixing apparatus according to the first or second aspect, both end portions in the width direction of the high resistance portion of the surface moving body that does not contact the image are thinner than other portions. The width of the high resistance portion in the other surface moving body is made larger than the contact width.

In this image fixing device, a thin portion of the high resistance portion of the surface moving body which does not contact the image is used.
The exposed portion of the conductive portion of the surface moving body is covered. In particular,
An example in which a heating roller and a pressing roller are provided as two surface moving members will be described. As shown in FIG. 7, provided at both ends of a high resistance portion 102b of a pressing roller 102 which is a surface moving member which does not contact an image, as shown in FIG. Press roller 102
Of the conductive portion 102a. In such a configuration, the exposed portion of the conductive portion 101a of the heating roller 101 and the exposed portion of the conductive portion 101a of the pressing roller 102 face each other with a high resistance portion interposed therebetween. For this reason, compared to the image fixing device 100 shown in FIGS. 5 and 6 in which the exposed portion of the conductive portion 101a and the exposed portion of the conductive portion 102a are directly opposed, the discharge between the conductive portions is suppressed. Can be. However, in this image fixing apparatus, as shown in FIG. 8, if the distance between the high resistance portion 101b of the heating roller 101 and the thin portion is too small, the thin portion and the heating Discharge occurs between the exposed portion of the conductive portion 101a of the roller 101, and there is a possibility that the thin portion and the end of the high-resistance portion 101b may be scorched.

Therefore, the invention of claim 4 is based on claims 1 and 2
Alternatively, in the image fixing device of the third aspect, an insulating portion made of an insulating material is provided in a non-contact area of the surface moving body that does not contact the image with the other surface moving body. .

In this image fixing device, the scorching of the high-resistance portion of the both-surface moving body can be suppressed more reliably than in the image fixing device of the third aspect. The reason for this will be described with reference to an example in which a heating roller and a pressing roller are provided as two surface moving bodies. That is, in the present image fixing apparatus of this example, as shown in FIGS. 9 and 10, the non-contact area between the heating roller 101 and the pressing roller 102, which is the surface moving body that does not contact the image,
d and 102e. These insulating portions 102d, 1
02e eliminates discharge between the thin portion of the high resistance portion 102b of the pressing roller 102 and the exposed portion of the conductive portion 101a of the heating roller 101, so that the high resistance portions 101b and 102b are scorched due to the discharge. Can be eliminated. Therefore, in the present image fixing device, scorching of the high-resistance portion of the both-surface moving body can be suppressed more reliably than the image fixing device of the third aspect. However, in the present image fixing device, for example, in the pressing roller 102 of FIGS. 9 and 10, if the insulating portions 102 d and 102 e and the high-resistance portion 102 b are not in close contact with each other, the pressing roller 102 may be formed between the contact surfaces. There is a possibility that a discharge may be caused between the conductive portion 101a of the heating roller 101 and the conductive portion 102a of the pressing roller 102 through the minute gap (hereinafter, this discharge is referred to as surface discharge). Regarding this creeping discharge, the insulating portion 102
d. It can be temporarily suppressed by bonding the insulating portion 102e and the high-resistance portion 102b with an adhesive. However, the adhesive surface formed by the adhesive gradually peels off due to repeated deformation of the high-resistance portion 102b and the like, so that creeping discharge cannot be continuously suppressed.

According to a fifth aspect of the present invention, in the image fixing device of the fourth aspect, the insulating portion provided on the surface moving body that does not contact the image is provided inside the high resistance portion of the surface moving body. It is characterized by being bitten.

In this image forming apparatus, it is possible to continuously suppress the creeping discharge caused by poor adhesion between the insulating portion and the high-resistance portion of the surface moving body that does not contact the image. The reason for this will be described with reference to an example in which a heating roller and a pressing roller are provided as two surface moving bodies.
That is, in the present image fixing device of this example, as shown in FIG. 11, for example, the insulating portions 102d and 102e bite into the high resistance portion 102b of the pressing roller 102 which is the surface moving body that does not contact the image. For this reason, as shown in FIG.
The cross-sectional shape of the creepage between d and 102e and the high resistance portion 102b is not linear but wedge-shaped. When such a creepage is formed, the heating roller 101 passes through the minute gap.
High resistance portion 101b and the conductive portion 10 of the pressing roller 102
Since the insulating portions 102d and 102e are interposed in the portion facing the portion 2a, lines of electric force are less likely to be formed therebetween. Also,
The creepage distance is longer than the creepage of a straight cross-sectional shape. As a result, the insulating portions 102d and 102e and the high-resistance portion 1
02b can be suppressed. In such a configuration, unlike the case where creeping discharge is temporarily suppressed by bonding with an adhesive, the insulating portion 102d,
The creeping discharge caused by poor adhesion between the high-resistance portion 102 and the high-resistance portion 102b can be continuously suppressed. However, in the image fixing device 100 shown in FIG. 11, as shown by the arrow D in the figure, the peripheral surfaces near both ends of the high resistance portion 101b of the heating roller 101 and the high resistance portion 102b of the pressing roller 102
Since the end face of the stepped portion is opposed to the end face via the air gap, there is a possibility that a discharge may occur between the two. Therefore,
In this image fixing device, there is a possibility that discharge will occur in the area where the high-resistance portion of the surface moving body that contacts the image and the end surface of the stepped portion of the high-resistance portion of the other surface moving body face each other. There is. The discharge is not limited to the present image fixing apparatus, and the high-resistance portion of one surface moving body and the high-resistance portion of the other surface moving body can face each other via a gap. Or, it may occur in the image fixing device of No. 5.

According to a sixth aspect of the present invention, in the image fixing apparatus of the first or second aspect, two insulating members adjacent to both ends in the width direction of the high resistance portion of the surface moving body which does not contact the image are provided. A high-resistance part and the two insulating parts are brought into contact with the high-resistance part of the other surface moving body by fixing a part on the conductive part of the surface moving body. It is.

In this image fixing device, the image fixing device is provided with a surface roller which is not in contact with the image, such as a pressing roller.
The two insulating portions are respectively adjacent to the end of the high resistance portion of the surface moving body and contact the high resistance portion of the other roller such as a heating roller. The state of contact in this way
FIG. 12 shows an example in which a heating roller and a pressing roller are provided as two surface moving bodies. In the figure, the insulating portions 102d and 102e are in contact with the high-resistance portion 101b of the heating roller 101 while being adjacent to the high-resistance portion 102b of the pressing roller 102, respectively. In this state, as shown in FIG.
02b and the high resistance portion 101b of the heating roller 101
Since no gap is formed between the end portion and the vicinity of the end portion by interposing the insulating portion 102d or the insulating portion 102e, discharge between the portions is eliminated. Therefore, in the present image fixing device, it is possible to eliminate the discharge between the high-resistance portions of both surface moving bodies. However, even in the present image fixing device, for example, FIG.
2, the insulating portions 102d and 102 of the pressing roller 102
e, a creepage discharge between the conductive parts of the two surface moving bodies through the insulating portion and the high resistance part of the surface moving body that does not contact the image, such as the creepage of the high resistance part 102b. Remains.

According to a seventh aspect of the present invention, in the image fixing device of the sixth aspect, the two insulating portions provided on the surface moving body which does not contact the image are respectively provided with the high resistance portions of the surface moving body. It is characterized by being cut into the inside of the.

In this image fixing device, by the same operation as the image fixing device of the fifth aspect, creeping discharge caused by poor adhesion between the insulating portion and the high resistance portion of the surface moving body which does not contact the image is continued. Can be suppressed.

In the image fixing apparatus 100 shown in FIG. 1, FIG. 2 or FIG. 3, the edge portion of the high resistance portion 101a of the heating roller 101 and the edge portion of the high resistance portion 102b of the pressing roller 102 It was confirmed that the scorching of both high-resistance portions 101b and 102b occurred locally even in a portion different from the contact region with. When this local scorch occurs, it is confirmed that a spark runs on the surface of the high-resistance portion 101a of the heating roller 101 and the high-resistance portion 102b of the pressing roller 102, so that discharge occurs inside these high-resistance portions. Seemed to occur locally.

A more detailed configuration of the image fixing device 100 shown in FIG. 1, FIG. 2 or FIG. 3 will be described below by taking the image fixing device shown in FIG. 3 as an example. 1. Heating roller 101 ・ Outer diameter φ: 40 [mm] ・ Material of conductive part 101a: hollow aluminum pipe ・ High resistance part: None ・ Roller heating temperature (fixing temperature) by halogen lamp 101c: 100 [° C.] ・ Circumferential speed: 150 [Mm / sec]-Electrical connection of conductive part 101a: ground Pressing roller 102 • Outer diameter φ of conductive part 102a: 30 [mm] • Material of conductive part 102a: stainless steel bar • Electrical connection of conductive part 102a: connected to power supply 103 • Thickness of high resistance part 102b: 5 [ mm]-Volume resistivity of the high resistance portion 102b: 10 ⁸ -10 ⁹
[Ω · cm]-Material of the high resistance portion 102b: Carbon black (CB) is dispersed as a conductive filler for adjusting electric resistance in a base material made of butadiene rubber (BR). Power supply 103-Outputs negative fixing bias to conductive part 102a-Constant current control of output current value to conductive part 102a

The present inventor has proposed an image fixing device 1 having such a configuration.
The material of the high resistance portion 102b of the pressing roller 102 at 00 was changed to the following six types of materials, and six experimental machines were manufactured. Disperse carbon black (CB) in a base made of silicone rubber (Q) Disperse CB in a base made of butyl rubber (IIR) Disperse CB in a base made of ethylene-propylene rubber (EPM) From fluorine rubber (FKM) CB dispersed on base material made of nitrile butadiene rubber (NBR)
Disperse B Consist only of substrate made of epichlorohydrin rubber (ECO)

In any type of material, the volume specific resistivity is set to 10 as in the image fixing apparatus 100 shown in FIG.
^It was adjusted to ⁸ to 10 ⁹ [Ω · cm]. When the materials are arranged in descending order of carbon black (CB) content,
,,, (Not contained).

The inventor of the present invention has set the bias supply time and the bias potential in these six experimental machines while controlling the output current value from the power supply 103 to the conductive part 102a to -1000 [μA]. Investigated the relationship.

Then, the result as shown in FIG. 13 was obtained. The power supply 103 sets the output current value of the fixing bias to -1.
000 [μA], the change in the fixing bias voltage value in each graph of FIG.
This indicates a change in electric resistance of the second high-resistance portion 102b. As shown in each graph, in the case where any one of the above-described materials is used as the material of the high resistance portion 102b of the pressing roller 102, the high resistance portion 1
02b tended to increase. However,
A group of materials that increase their electrical resistance rapidly,
It was divided into a group of materials that increased relatively slowly. The above and materials correspond to the former group, and the above and correspond to the latter group.

In the former group of materials, when the fixing bias voltage value is increased to a certain value (destruction point), a partial scorch is formed due to the generation of a local discharge, and thereafter, the electric resistance value is rapidly decreased. However, no scorch occurred in the latter group of materials. In the former group of materials, as a result of the bias potential becoming too high with an increase in the electric resistance value, a portion where the dispersion density of carbon black is high inside the material and a portion where the dispersion density is high similarly It is considered that discharge occurred between the two. When the materials from above are arranged in order of increasing electric resistance value,
,,, And becomes the same as the order of the CB content rate. Therefore, it is considered that the higher the CB content, the more rapidly the electric resistance value increases with the supply of bias, and the easier it is to generate local discharge inside.

Further, the present inventor has found that the electric resistance value is rapidly increased.
Group material to be added, increase relatively slowly
There is a difference in the molecular structure of the base material from the group material
Was found. Specifically, the base material in the former group
Consists of non-polar molecules, whereas the latter group
The substrate comprises polar molecules. Figure 14 shows non-polar molecules
A typical elastic material and a typical
An example with an elastic material is shown. As shown, non-polar molecules are charged
Has a stable molecular bonding force.
Polar molecules are polar groups with unstable electron binding (SO₂Cl
Group, Cl group, CF ₃Group, Sx group, O group (double bond), C
N group, CH₂Cl group). Figure 1, Figure 2 or
In the image fixing device 100 shown in FIG.
Butadiene is used as the base material of the high resistance portion 102b of the pressing roller 102.
Rubber (BR) is used, as shown in FIG.
Is a non-polar molecule.

FIG. 15 shows each elastic material having a nonpolar molecular structure.
Temperature and volume resistivity (without CB)
FIG. 1 is a graph showing an example of the relationship with the resistivity in FIG.
6 shows the same example in each elastic material having a polar molecular structure.
It is rough. Comparing these figures, polar molecules
Structured materials are much lower than nonpolar molecular structured materials
It can be seen that a high specific volume resistivity is exhibited. Difference between the two
Is 10 ³There is an order, a big one
Is 10⁷It will be an order. Polar molecules are called polar groups
Since it has a molecular structure that can easily transfer electrons, it is non-polar
This is because current flows more easily than molecules. Yo
The electrical resistance of the material in which the substrate made of non-polar molecules is used.
The resistivity and the electric charge of the material used for the substrate composed of polar molecules
To lower the air resistance to the same value,
Much higher conductivity for the latter material than for the latter material
It is necessary to disperse the filler, and the former material becomes conductive.
It is easy to form a locally dense region of the conductive filler.

In general, since conductive fillers having extremely low electric resistivity such as CB are used, non-polar molecules having much higher electric resistivity than polar molecules have
The difference in electric resistivity between the conductive filler and the conductive filler is much larger than that of the polar molecule.

As described above, in the material having the substrate made of non-polar molecules, the rate of increase in the electrical resistivity is higher than that in the material having the substrate made of polar molecules, and the local denseness of the conductive filler is increased. , And the difference in electrical resistivity between the conductive filler and the substrate becomes much larger. As a result, it is considered that local discharge is more easily generated inside than the latter material.

In view of the above test results, the invention of claim 8 is provided with two surface moving bodies for moving the surfaces while contacting each other, and an image is formed by a colored liquid containing a liquid carrier and chargeable colored particles. An image fixing device for fixing an image to a recording member by sandwiching the formed recording member between both surface moving bodies, the image fixing device comprising a conductive portion made of a conductive material and a material having a higher electric resistivity than the conductive portion. A conductive high-resistance portion fixed to the conductive portion so as to be in contact with another surface moving body is provided on at least one surface moving body, and the other surface moving body is made of a conductive material. A potential difference generating means for generating a potential difference between the other surface moving body and the conductive portion, and a substrate made of a polar molecule is used as a base material of the high resistance portion. In things That.

In this image fixing device, when a potential difference is generated between the conductive portion of one surface moving body and the other surface moving body, a current flows between the two surface moving bodies via the recording member. Therefore, it is possible to improve the fixing performance by flowing a current between the two surface moving members via the recording member. Further, since a material made of polar molecules is used as the base material of the high resistance portion, local discharge inside the high resistance portion is suppressed as compared with the case where a material made of non-polar molecules is used. Therefore, the local scorching of the high-resistance portion can be suppressed as compared with the case where the base material of the high-resistance portion is made of a nonpolar molecule.

According to a ninth aspect of the present invention, in the image fixing device of the eighth aspect, the high resistance portion is formed by dispersing a conductive filler in the base material.

In this image fixing device, by dispersing the conductive filler in the base material, the electric resistivity of the high resistance portion can be easily reduced to a desired value.

According to a tenth aspect of the present invention, in the image fixing device of the eighth or ninth aspect, an elastic material is used as the base made of polar molecules.

In this image fixing apparatus, the adhesion between the both-surface moving members is enhanced by the high-resistance portion exhibiting elasticity, as compared with the case where the both-surface moving members are each constituted only by a conductive portion made of a metal material or the like. Fixing performance can be improved.

According to an eleventh aspect of the present invention, in the image fixing device of the tenth aspect, chlorosulfonated polyethylene, fluoro rubber, polysulfide rubber, urethane rubber, nitrile butadiene rubber or epichlorohydrin rubber is used as the elastic material. It is characterized by the following.

In this image fixing device, a high-resistance portion made of chlorosulfonated polyethylene, fluorine rubber, polysulfide rubber, urethane rubber, nitrile butadiene rubber or epichlorohydrin rubber is used while exhibiting good elasticity. , Can suppress the local scorch.

According to a twelfth aspect of the present invention, in the image fixing apparatus of the eleventh aspect, epichlorohydrin rubber is used as the elastic material.

Epichlorohydrin rubber, which is the base material of the high resistance portion of the surface moving body in this image fixing device, is shown in FIG.
As shown in FIG. 13, the elastic material has an extremely low electric resistivity, and as shown in FIG. 13, the rate of increase in the electric resistance with the passage of the bias supply time is also extremely low. For this reason, local scorching of the high-resistance portion of the surface moving body can be further suppressed.

The thirteenth aspect of the present invention provides the first aspect,
4, 5, 6, or 7, wherein a conductive protective layer is provided on the surface of the high-resistance portion of the surface moving body in contact with the image.

Further, the invention of claim 14 is the invention of claim 8,
In the image fixing device of 9, 10, 11, 12, or 13, the conductive member and the high-resistance portion are provided on the surface moving body that comes into contact with the image, and the surface of the high-resistance portion has a conductive property. It is characterized in that a protective layer is provided.

In these image fixing devices, a protective layer is provided on the surface of the high-resistance portion of the surface moving body that comes into contact with the image, such as a heating roller, so that the high-resistance portion has abrasion resistance and resistance. Ozone properties, solvent resistance, etc. can be exhibited. Therefore, it is possible to suppress deterioration of the high-resistance portion due to abrasion of the surface, ozone generated by electric discharge inside the device, infiltration of the liquid carrier of the colored liquid, and the like.

The invention of claim 15 is the invention of claim 13 or 14
In the above image fixing apparatus, a heating means for heating the surface moving body which comes into contact with the image is provided.

In this image fixing device, the colored particles in the image on the recording member sandwiched between both surface moving members are pressed while being softened or melted by heating. In such a configuration, the fixing performance can be further improved as compared with the case where the colored particles in the image are not heated.

According to a sixteenth aspect of the present invention, in the image fixing device of the fifteenth aspect, a fluororesin is used as a base material of the protective layer.

In this image fixing apparatus, the protective layer made of a fluororesin exhibits excellent liquid repellency and releasability, so that the surface moving body that comes into contact with the image and the colored body in the image The colored substance obtained by softening or melting the particles can be separated well.

According to a seventeenth aspect of the present invention, in the image fixing device of the fifteenth aspect, the protective layer is formed of a material whose main component is the same as the main component of the liquid carrier in the colored liquid. Is what you do.

"Colored liquid" in this image fixing device
Indicates a colored liquid of a type designated by a manufacturer or a distributor of the image fixing device. The designation is such that the product name and standard of the usable colored liquid are described in the instruction manual or the sticker of the image fixing device or the image forming device including the same, or the colored liquid is packed together with the image forming device. And so on. In this image fixing device, the protective layer containing the main component of the liquid carrier as the main component is well wetted by the liquid carrier, so that the liquid component is easily interposed between the softened or melted colored substance and the colored substance is easily removed. To separate.

According to the eighteenth aspect of the invention, a recording member on which an image is formed by a colored liquid containing a liquid carrier and chargeable colored particles is sandwiched between two surface moving bodies which move while contacting each other. In an image fixing method for performing a fixing step of fixing the image to the recording member, the fixing step is performed in the fixing step.
7, 8, 9, 10, 11, 12, 13, 14, 15, 1,
It is characterized by using the image fixing device of 6 or 17.

In this image fixing method, an electric current flows between the two surface moving members via the recording member in the fixing step to improve the fixing performance by the same operation as the image fixing device of the first or eighth aspect. be able to. Further, scorching of the high-resistance portion of the surface moving body in the fixing step can be suppressed.

According to a nineteenth aspect of the present invention, there is provided an image forming means for forming an image on a recording member using a color liquid containing a liquid carrier and chargeable colored particles, and an image for fixing the image to the recording member. An image forming apparatus comprising: a fixing device;
4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 1
It is characterized in that 4, 15, 16 or 17 image fixing devices are provided.

In this image forming apparatus, a current flows between the two surface moving members via the recording member in the image fixing device, thereby improving the fixing performance. Can be improved. Further, scorching of the high-resistance portion of the surface moving body in the image fixing device can be suppressed.

According to a twentieth aspect of the present invention, there is provided an image forming step of forming an image on a recording member using a colored liquid containing a liquid carrier and chargeable colored particles, and fixing the image to the recording member. The method according to claim 1, wherein the fixing step comprises:
6, 7, 8, 9, 10, 11, 12, 13, 14, 1
5, 16, or 17 of the image fixing device is used.

In this image forming method, an electric current flows between the two surface moving members via the recording member in the fixing step using the image fixing device by the same operation as the image fixing device of claim 1 or 8. Fixing performance can be improved. In addition, scorching of the high resistance portion of the surface moving body can be suppressed in the fixing step using the image fixing device.

[0065]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment in which the present invention is applied to an electrophotographic printer as an image forming apparatus will be described below. FIG. 17 is a schematic configuration diagram of the printer. In the figure, the printer has four image forming units 1Y, 1M, 1
C, 1Bk. Further, a transfer device 60 and an image fixing device (hereinafter, simply referred to as a fixing device) 100 are also provided.

First, the image forming unit 1 among these apparatuses will be described. The image forming units 1Y, 1
M, 1C, and 1Bk form a yellow image, a magenta image, a cyan image, and a black image, respectively, and include a photosensitive drum 10, a charging device 20, a laser writing unit (not shown), a developing device 40, and a drum cleaning blade 50, respectively. , A static elimination lamp 51 and the like (hereinafter, black, cyan, magenta, and yellow are referred to as Bk, C, M, and Y, respectively).

The photosensitive drum 10 is configured to be driven to rotate in a direction indicated by an arrow in the figure by driving means (not shown).
0, developing device 40, drum cleaning blade 50,
A static elimination lamp 51 is provided.

After the surface of the photosensitive drum 10 is uniformly charged by the charging device 20 as the surface of the photosensitive drum 10 rotates, the laser beam 30 is emitted from the laser writing unit.
To carry an electrostatic latent image for Y, M, C or Bk. These electrostatic latent images are stored in a developing device 4 using a liquid developer.
After being developed into a Y, M, C or Bk image on the photosensitive drum 10 by 0, the image is transferred onto an intermediate transfer belt described later. After the transfer, the surface of the photosensitive drum 10 is discharged by a discharge lamp 51 after the untransferred liquid developer is removed by a drum cleaning blade 50.

Image forming units 1Y, 1M, 1C, 1B
Each of the developing devices 40 uses a liquid developer having a viscosity of 100 to 10000 [mPa · s] in which Y, M, C, and Bk toners are dispersed in silicone oil as a liquid carrier. , M, C, and Bk are developed into the Y, M, C, and Bk images.

These Y, M, C, and Bk toners, which are colored particles, are respectively added to a modified epoxy resin which starts softening at 50 ° C., a coloring pigment (disazo yellow, quinacridone, copper phthalocyanine or carbon black), It contains a charge control agent and a dispersant. Its average particle size is adjusted to about 3 [μm], and it is positively charged in silicone oil.

The basic structure of each developing device 40 is as follows. That is, the developing device 40 includes a developer tank 42 for storing the liquid developer 18, a developing roller 41 disposed in contact with the surface of the photoconductor drum 10, a coating roller 43, and a removing blade 44.

The application roller 43 is connected to the developer tank 42
The liquid developer 18 as a colored liquid drawn from the surface is applied to the surface of the developing roller 41. By this application, a thin layer of the developing solution having a uniform thickness is formed on the developing roller 41. A positive developing bias is applied to the developing roller 41 by a power supply (not shown).

Of the toner (positive polarity) in the thin developing solution transported to the developing area where the developing roller 41 and the photosensitive drum 10 are in contact with each other, the electrostatic latent image on the photosensitive drum 10 Are electrophoresed toward the electrostatic latent image from the surface of the developing roller 41 to which the developing bias is applied. The photosensitive drum 10 at a position facing the background portion (non-latent image portion) electrophoreses toward the surface of the developing roller. Due to the electrophoresis, the liquid developer 18 containing a very high concentration of toner in a small amount of silicone oil adheres to the electrostatic latent image on the photosensitive drum 10. Further, only the colorless silicone oil adheres to the background of the photosensitive drum 10.

The developing solution thin layer remaining on the developing roller 41 after the completion of the development is removed from the roller surface by the removing blade 44 and returns to the inside of the developer tank 42 by gravity.

Next, the transfer device 60 will be described. The transfer device 60 includes an intermediate transfer belt 61, a driving roller 62, a secondary transfer bias roller 63, two tension rollers 64 and 65, four primary transfer bias rollers 66,
67, 68, 69, belt cleaning roller 70, roller cleaning blade 71, secondary transfer pressing roller 7
2 and so on.

The intermediate transfer belt 6 formed endlessly
Reference numeral 1 denotes an endless belt in which a medium-resistance conductive rubber in which carbon powder is dispersed is coated with a fluorine-based resin for improving the smoothness of the belt surface. The intermediate transfer belt 61 is endlessly moved in a direction indicated by an arrow in the figure by the driving of the drive roller 62 while being stretched by the drive roller 62, the secondary transfer bias roller 63, and the two stretch rollers 64 and 65. With this endless movement,
The surface of the intermediate transfer belt 61 includes the image forming units 1Y, 1
The photoconductor drums 10 of M, 1C, and 1Bk are sequentially contacted.

The primary transfer bias rollers 66, 67,
Reference numerals 68 and 69 are disposed so as to press the intermediate transfer belt 61 from the back surface thereof toward the photosensitive drums 10 of the image forming units 1Y, 1M, 1C and 1Bk, respectively.
Form a primary transfer nip. Primary transfer bias rollers 66, 67, 68, which form such a primary transfer nip,
A negative primary transfer bias is applied to 69 by a power supply (not shown). By applying the primary transfer bias, a primary transfer electric field is formed in each primary transfer nip.
The Y image, M image, C image, and Bk image developed on the photoconductor drum contain the Y toner, M toner, C toner, and Bk toner charged to a positive polarity at an extremely high density as described above. The primary transfer is performed on the intermediate transfer belt 61 by the action of the primary transfer electric field and the nip pressure in the primary transfer nip.
The Y image, the M image, the C image, and the Bk image are sequentially superimposed and transferred onto the surface, and a full-color image is formed on the intermediate transfer belt 61 by such superimposed transfer.

The secondary transfer bias roller 63 is applied with a positive secondary transfer bias as shown in the figure, and is pressed by the secondary transfer pressing roller 72 via the intermediate transfer belt 61. Due to this pressing, a secondary transfer nip is formed between both rollers. The full-color image formed on the intermediate transfer belt 61 enters the secondary transfer nip with the endless movement of the belt. On the other hand, a paper feeding unit (not shown) feeds the recording paper 200 as a recording member toward the secondary transfer nip at a timing at which the recording paper 200 can be superimposed on a full-color image. In the secondary transfer nip, a full-color image on the intermediate transfer belt 61 is secondarily transferred onto the recording paper 200 by the action of a secondary transfer electric field or nip pressure formed by the influence of the secondary transfer bias.

The belt cleaning roller 70 is provided between the intermediate transfer belt 6 and the driving roller 62 which is grounded.
1 is sandwiched therebetween, and a negative cleaning bias is applied in contact with the image transfer surface of the belt. The untransferred liquid developer 18 remaining on the surface of the intermediate transfer belt 61 after the completion of the secondary transfer moves onto the cleaning roller 70 under the influence of the cleaning bias. Then, it is removed from the cleaning roller 70 by a roller cleaning blade.

Recording paper 20 having passed through the secondary transfer nip
0 is discharged outside the apparatus after the full-color image is fixed in the fixing device 100.

Next, the fixing device 100 having the characteristic structure of the present invention will be described. FIG. 18 (a),
2B is a horizontal cross-sectional view and a vertical cross-sectional view illustrating a schematic configuration of the fixing device 100, respectively. In the figure, a fixing device 1
Reference numeral 00 includes a heating roller 101 which is a surface moving body, a pressing roller 102 which is also a surface moving body, a power source 103, a separation claw 104, and the like.

The heating roller 101 is made of a conductive part 101a made of aluminum and formed in the shape of a hollow roller having an outer diameter of 40 [mm], and a high resistance part 101b fixed thereon.
And a halogen lamp 101c as a heating means disposed inside the conductive portion 101a. Conductive part 10
1a is grounded as shown. The high resistance portion 101b is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) as a base material.
In this case, fine powder of carbon black as a conductive filler is dispersed, and the volume specific resistivity is adjusted to 10 ¹² [Ω · cm].

When the fixing device 100 is driven, the halogen lamp 101c is turned on / off by a lamp control means (not shown), and the heating roller 101 is heated to 90 ° C.
Heated. The heating roller 101 is driven to rotate at a peripheral speed of 150 [mm / sec] in a direction indicated by an arrow in FIG.

The pressing roller 102 has an outer diameter of 30 [m
m], a conductive portion 102a made of a stainless steel rod, and a high-resistance portion 102b having a thickness of 5 mm fixed thereon.
And two insulating portions 102d made of silicone rubber or the like,
102e. In addition, the high-resistance portion 102b and the insulating portions 102d and 102e are disposed so as to rotate while being in contact with the high-resistance portion 101b of the heating roller 101, and the high-resistance portion 102d is deformed by this contact to form a fixing nip. I do. High resistance portion 10 of pressing roller 102
Reference numeral 2b denotes a base material made of ethylene-propylene rubber (EPM) in which carbon black fine powder is dispersed so as to exhibit a predetermined volume resistivity at a fixing temperature of 90 ° C.

The power source 103 is connected to the conductive portion 101a of the pressing roller 101, and is controlled by a constant current of -50.
A fixing bias of 0 [μA] is output.

The recording paper 200 on which the full-color image has been secondarily transferred at the secondary transfer nip is conveyed between the heating roller 101 and the pressing roller 102, and the image forming surface thereof is brought into contact with the heating roller 101. It is sandwiched between both rollers. The toner of each color in the full-color image on the recording paper 200 sandwiched in this manner is heated to 50 ° C. or more by the heating roller 101 and melted. And
The recording paper 200 is electrostatically charged by the influence of the fixing bias.
It is pressed while being drawn to the surface, and is fixed on the recording paper 200. As described above, the fixing performance can be improved as compared with the conventional fixing device by electrostatically moving and pressing each color toner while melting it.

As shown in FIG. 18B, the width W1 of the high resistance portion 101b of the heating roller 101 is larger than the contact width W2 of the high resistance portion 101b and the high resistance portion 102b of the pressing roller 102. ing. Thus, the width W
1 is larger than the contact width W2, the pressing roller 1
02, the exposed portion of the conductive portion 102a and the heating roller 101
The lines of electric force formed between the exposed portion of the conductive portion 101a of the pressing roller 102 do not pass through the inside of the conductive portion 102a of the pressing roller 102. As a result, the high resistance portion 1 of the heating roller 101
The concentration of current on the edge portion 01b is eliminated, the scorching of the edge portion and the contact portion of the high-resistance portion 102b of the pressing roller 102 with the edge portion is suppressed, and the current amount in the fixing width W3 increases. The fixing efficiency is improved.

The insulating portions 102d and 102e are
The heating roller 101 is in contact with the high-resistance portion 101b of the heating roller 101 while being adjacent to the high-resistance portion 102b of the pressing roller 102. The side surface of the former high-resistance portion 102b and the end of the latter high-resistance portion 101b. Avoid intervening gaps with the vicinity. For this reason, discharge between both high resistance parts is eliminated, and scorching of both high resistance parts 101b and 102b is further suppressed.

Further, these insulating portions 102d, 102e
Are fixed to the conductive portion 102a so as to bite into the high resistance portion 102b of the pressing roller 102. When the insulating parts 102d and 102e bite in this way, the insulating parts 102d and 102e
Insulating portions 102d and 102e intervene in a portion where the high-resistance portion 101b of the heating roller 101 and the conductive portion 102a of the pressing roller 102 pass through a minute gap on the surface between the high-resistance portion 102b and the high-resistance portion 102b. Become. Due to this interposition, it is difficult to form lines of electric force between the high resistance portion 101b of the heating roller 101 and the conductive portion 102a of the pressing roller 102. In addition, the creepage distance is longer than the creepage of the straight cross-sectional shape. As a result, the insulating portions 102d, 1
The creeping discharge between the high resistance portion 102b and the high resistance portion 102b is suppressed, and the scorching of the high resistance portions 101b and 102b is further suppressed.

According to the fixing device 100 having the above configuration, the high resistance portion 101b of the heating roller 101 and the pressing roller 10
The second high-resistance portion 102b is different from the second high-resistance portion 102b.
Burn due to current concentration on the edge portion of 1b,
Since the scorch caused by the discharge between the two high-resistance portions and the scorch caused by the creeping discharge are suppressed, the scorch of the both high-resistance portions can be suppressed extremely favorably.

In addition, the driving torque of the heating roller becomes unstable due to the discharge, the electric signal in the electric circuit is disturbed,
As a result, a malfunction caused by this disturbance can be suppressed favorably.

FIG. 19 is a sectional view showing a modification of the fixing device 100. As shown in FIG. In this modified example, as shown, a high resistance portion 102b having a thickness of 3 [mm] made of EPM is fixed to a conductive portion 102a made of a stainless steel rod having an outer diameter of 8 [mm]. It has two pressing rollers 102, which are rotated while being in contact with the heating roller 101. By causing the four pressing rollers 102 to abut on the heating roller 101 in this manner, four fixing nips are formed, and the distance over which the recording paper 200 passes through the fixing nip is increased. Therefore, the fixing can be performed in a shorter time, and the peripheral speeds of the heating roller 101 and the pressing roller 102 can be increased. In this modified example, these rollers are
300 [mm / sec] which is twice the fixing device 100 shown in FIG.
c), the same fixing performance as that of the fixing device 100 can be exhibited.

Further, in the present modified example, the conductive portion 102b of the pressing roller 102 located at the most downstream side is grounded, and the conductive portions 102b of the other pressing rollers 102 are respectively -5.
A constant current of 00 [μA] is supplied. In this way, by grounding the conductive portion 102b of the pressing roller 102 located at the most downstream side, the recording paper 1 that has passed through the fourth fixing nip
By removing the static electricity from 00, the wrapping around the heating roller 101 can be reduced and the separability between the two can be enhanced.

FIG. 20 is a sectional view showing another modified example of the fixing device 100. In the figure, this modification includes a pressing belt unit 105 instead of the pressing roller 102. This pressing belt unit 105
Has a power source 103, a pressing belt 106 which is a surface moving body that does not contact an image, a driving roller 107, a fixing bias roller 108, and the like.

FIG. 21 is a sectional view showing the pressing belt 106. As shown in FIG. In the drawing, this pressing belt 106 has a thickness of 150 [μm] and a volume resistivity of 10 ³ [Ω · cm].
A high resistance portion 106b made of EPM having a thickness of 1 [mm] is coated on a central portion on the conductive portion 106a made of an endless polyimide belt. Also, the conductive portion 106a
Both upper ends are covered with elastic insulating portions 106d and 106e made of silicone rubber or the like. The high resistance portion 106 b has a width equal to that of the high resistance portion 1 of the heating roller 101.
01b is smaller than the width W1 and larger than the fixing width W3. With this configuration, scorching caused by current concentration on the edge portion of the high resistance portion 101b of the heating roller 101 is suppressed, and the fixing width W
3, the fixing efficiency can be improved by increasing the amount of current.

In the pressing belt 106, the insulating portions 106d and 106e are coated on the conductive portion 106a so as to bite into the high resistance portion 106b. With this configuration, the insulating sections 106d and 106e and the high-resistance section 106b
And the scorching of the high resistance portion 106b and the high resistance portion 101b of the heating roller 101 can be further suppressed. In the illustrated example, the insulating portion 106d,
The thickness of the fixing device 106e is smaller than that of the high-resistance portion 106b so as not to make contact with the high-resistance portion 101b of the heating roller 101. Similarly to the above, the discharge between the two high-resistance portions can be eliminated, and the scorching of both the high-resistance portions can be further suppressed.

The pressing belt 106 having such a configuration is rotated by the driving roller 107 while being stretched by the driving roller 107 and the fixing bias roller 108.
Is moved endlessly in the direction of the arrow in the figure.

The power supply 103 for controlling the output current to a constant current of -1500 [μA] is connected to the fixing bias roller 108 made of a conductive material.

The pressing belt 106 is in contact with the heating roller 101 so as to be wound therearound as shown in the figure.
By such a contact, about 1/1 of the circumference of the heating roller 101 is obtained.
A very long fixing nip of 4 is formed. Therefore, also in the present modified example, fixing can be performed in a shorter time, and the peripheral speed of the heating roller 101 can be increased. This peripheral speed is set to 300 [mm / sec].

[Second Embodiment] Next, a second embodiment in which the present invention is applied to an electrophotographic printer which is an image forming apparatus will be described. Note that the basic configuration of this printer is the same as that of the printer of the first embodiment, and a description thereof will be omitted.

The appearance of the fixing device 100 in this printer is exactly the same as the fixing device 100 shown in FIGS. 18 (a) and 18 (b). Therefore, the configuration of the fixing device 100 in the printer will be described below with reference to these drawings.

The heating roller 1 in the fixing device 100
PFA having a non-polar molecular structure is used for the base material of the high-resistance portion 101b of No. 01 and the high-resistance portion 102b of the pressing roller 102.
An elastic material having a polar molecular structure (hereinafter referred to as a polar elastic material) is used instead of the EPM. Specifically, chlorosulfonated polyethylene (CSM), fluoro rubber (FKM), polysulfide rubber (T), urethane rubber (U), nitrile butadiene rubber (NBR), homopolymer epichloro Hydrin rubber (ECO) or random copolymer epichlorohydrin rubber (CO) is used. Since these polar elastic materials exhibit a much lower volume resistivity than the material having a nonpolar molecular structure, the two high-resistance portions 101b and 102b
Is much smaller than in the first embodiment, and it is difficult to form a locally dense region of carbon black in both high-resistance portions 101b and 102b. In addition, these polar elastic materials have a much smaller difference in electrical resistivity from carbon black and the rate of increase in electrical resistance with the lapse of the fixing bias supply time than materials having a nonpolar molecular structure. Therefore, both high resistance portions 101b, 10b
The two high-resistance portions 101b and 102b are different from those in the case where base materials each having a non-polar molecular structure are used for the base material 2b.
Polar discharge in the inside can be suppressed, and local scorching of both high resistance portions 101b and 102b due to this discharge can be suppressed.

As polar elastic materials, CSM, FKM,
Regarding which one of T, U, NBR, ECO, and CO is used, electric resistivity to be exhibited by both high resistance portions 101b and 102b, possibility of discharge in the fixing device 100,
It is desirable to determine based on the melting start temperature of the toner, the type of liquid carrier (solvent), and the like.

When a toner having a relatively high melting start temperature is used, it is naturally necessary to set the fixing temperature to a relatively high temperature. Therefore, it is desirable to use a polar elastic material having excellent heat resistance. Here, regarding the glass transition point of the resin component of the toner or the melting point of the elastomer component,
Considering that the recording member such as the recording paper 200 after the image is fixed can be exposed and stored under various environments, it is considered that the temperature needs to be adjusted to at least 40 ° C. or more.
Further, the fixing temperature is desirably set at least about 20 ° C. lower than the heat resistant temperature of the polar elastic material. Therefore, for the polar elastic material, 60
It is desirable to use one having a heat resistance temperature of [° C.] or more.

When there is a possibility that some kind of discharge may occur in the fixing device 100, a polar elastic material having excellent ozone resistance is used in order to suppress deterioration of the high resistance portion 102b of the pressing roller 102 due to ozone generated by the discharge. It is desirable to use As shown in FIG. 14, since NBR has poor ozone resistance, it is not preferable to use it in an environment where ozone is generated. However, only the surface of the high-resistance portion 102b that can come into contact with ozone is on the surface.
If 2b is coated with a conductive protective tank having excellent ozone resistance, NBR can be used even in an environment where ozone is generated.

Examples of the material of such a protective layer include polyvinylidene fluoride (PVDF), tetrafluoroethylene-ethylene copolymer (ETFE), polytetrafluoroethylene (PTFE), and tetrafluoroethylene-perfluoroalkylvinyl ether copolymer. Polymer (PF
A) and the like. Since these materials are insulating, it is necessary to impart conductivity by dispersing a conductive filler such as carbon black powder. However, if the present inventor forms a protective layer having a thickness of about several microns by coating or the like, even if the protective layer is not provided with conductivity by a conductive filler, the distance between the heating roller 101 and the pressing roller 102 can be reduced. Has little effect on the current-voltage characteristics at

When a highly corrosive solvent is used as the liquid carrier of the liquid developer 18, it is preferable to use a polar elastic material having excellent solvent resistance. However, if both the high resistance portions 101b and 102b are coated with a protective layer having excellent solvent resistance, a polar elastic material having poor solvent resistance may be used.

The material of the protective layer that covers the high-resistance portion 101b of the high-resistance portions 101b and 102b that comes into contact with the image on the recording paper 200 may be wettability or non-wetting by the liquid carrier in order to suppress the occurrence of offset. It is desirable to determine based on the releasability.

For example, PVDF, ETFE, PTFE, and PFA listed above as the material for the protective layer are all fluorine-based resins and exhibit excellent liquid repellency and releasability, and were melted by heating. Good separation from fused toner. Therefore, occurrence of an offset can be suppressed.

Also, the protective layer whose main component is the same as the main component of the liquid carrier is very easy to wet the liquid carrier,
The molten toner on the recording paper 200 is satisfactorily separated. Book second
In the printer of the embodiment, since a liquid containing silicone oil is used as the liquid carrier, it is preferable to use silicone rubber, silicone resin, or the like as the base material of the protective layer.

The same configuration as that of the modification shown in FIGS. 19 and 20 can be applied to the fixing device 100 in the printer of the second embodiment.

In each of the embodiments described above, a printer that forms an image by an electrophotographic method has been described. However, an image forming apparatus using a colored liquid as an image forming substance, such as an ink jet method or a printing method using a printing plate, may be used. For example, the present invention can be applied.

[0113]

According to the present invention, claims 1, 2, 3, 4, 5, 6, 7,
According to the invention of 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17, it is possible to improve the fixing performance by flowing a current between the two surface moving members via the recording member. There is an excellent effect. Further, there is an excellent effect that scorching of the high resistance portion of the surface moving body can be suppressed.

In particular, according to the first, second, third, fourth, fifth, sixth or seventh aspect of the present invention, the edge portion of the high resistance portion in the surface moving body which comes into contact with the image, such as a heating roller, There is an excellent effect that the scorching of the contact area with the edge portion in the high resistance portion of the surface moving body can be suppressed. Further, there is an excellent effect that the fixing efficiency can be further improved. In addition, when both surface moving bodies are each composed only of a conductive portion made of a metal material or the like,
As compared with the case where the high-resistance portion is provided only on one surface moving body as in the image fixing device 100 shown in FIGS. 2 and 3, it is possible to enhance the adhesion between the two surface moving bodies and improve the fixing performance. Has an excellent effect.

According to the second aspect of the present invention, the width of the high-resistance portion of the surface moving body that comes into contact with the image of the recording member has the same size as the contact width of the high-resistance portion of both surface moving bodies. As compared with the case of (1), there is an excellent effect that the scorching of the high-resistance portion of the both-surface moving body can be suppressed and the fixing efficiency can be improved.

In particular, according to the third aspect of the present invention, the discharge between the conductive parts of both surface moving bodies can be suppressed as compared with the case where the exposed portions of the conductive parts of both surface moving bodies are directly opposed to each other. Has an effect.

In particular, according to the invention of claim 4, there is an excellent effect that the scorching of the high-resistance portion of the both-surface moving body can be suppressed more reliably than the invention of claim 3.

According to the fifth aspect of the present invention, the creeping discharge caused by poor adhesion between the insulating portion and the high-resistance portion of the surface moving body that does not contact the image is continuously suppressed.
There is an excellent effect that scorching of the high resistance portion of both surface moving bodies can be suppressed more reliably.

Further, according to the invention of claim 6 or 7, since the discharge between the high-resistance portions of both surface moving bodies is eliminated,
There is an excellent effect that the scorching of the high-resistance portion can be suppressed as compared with the invention of claim 3, 4 or 5 which can generate the discharge.

In particular, according to the seventh aspect of the present invention, creeping discharge caused by poor adhesion between the insulating portion and the high-resistance portion of the surface moving body that does not contact the image is continuously suppressed. There is an excellent effect that the scorching of the high-resistance portion of the both-surface moving body can be suppressed more reliably than the invention.

In particular, claims 8, 9, 10, 12, 1
According to the invention of 3, 14, 15, 16 or 17, there is an excellent effect that local scorching of the high resistance portion can be suppressed.

In particular, according to the ninth aspect of the invention, there is an excellent effect that the electric resistivity of the high resistance portion can be easily reduced to a desired value.

According to the tenth, eleventh, and twelfth aspects of the present invention, the high-resistance portions exhibiting elasticity make the both-surface moving body more compact than the case where each of the both-surface moving bodies is formed only of a conductive portion made of a metal material or the like. There is an excellent effect that the adhesion of the surface moving body can be enhanced to improve the fixing performance.

According to the eleventh or twelfth aspect of the present invention, the high-resistance portion based on chlorosulfonated polyethylene, fluoro rubber, polysulfide rubber, urethane rubber, nitrile butadiene rubber or epichlorohydrin rubber has There is an excellent effect that local scorch can be suppressed while exhibiting good elasticity.

According to the twelfth aspect of the present invention, there is an excellent effect that local scorching of the high-resistance portion of the surface moving body can be further suppressed.

In particular, claims 13, 14, 15, 16
According to the seventeenth aspect, deterioration of the high-resistance portion of the surface moving body that comes into contact with the image due to abrasion of the surface, ozone generated by discharge inside the device, infiltration of the liquid carrier of the colored liquid, and the like. There is an excellent effect that it can be suppressed.

In particular, according to the invention of claim 15, 16 or 17, there is an excellent effect that the fixing performance can be further improved as compared with the case where the colored particles in the image are not heated.

In particular, according to the invention of claim 16 or 17, since the surface moving body in contact with the image and the colored substance in the image are satisfactorily separated, the color moving on the surface moving body is improved. There is an excellent effect that the occurrence of offset due to the remaining material can be suppressed.

According to the eighteenth aspect, in the fixing step, there is an excellent effect that a current can flow between the two surface moving members via the recording member to improve the fixing performance. Further, in the fixing step, there is an excellent effect that scorching of the high resistance portion of the surface moving body can be suppressed.

According to the nineteenth aspect, there is an excellent effect that a current can be passed between two surface moving members via a recording member in an image fixing device to improve the fixing performance. Also, there is an excellent effect that scorching of the high resistance portion of the surface moving body can be suppressed in the image fixing device.

According to the twentieth aspect, in the fixing step using the image fixing device, an excellent effect that a current can flow between two surface moving members via the recording member to improve the fixing performance can be obtained. There is. Further, in a fixing step using an image fixing device, there is an excellent effect that scorching of a high resistance portion of a surface moving body can be suppressed.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating a schematic configuration of a fixing device under development. (B) is a longitudinal sectional view showing the identification attachment device.

FIG. 2 is a cross-sectional view illustrating a modified example of the identification attachment device.

FIG. 3 is a sectional view showing another modified example of the identification attachment device.

FIG. 4 is a schematic view showing electric lines of force formed between rollers in the identification and attachment device.

FIG. 5 is a schematic configuration diagram illustrating an example of a fixing device according to the present invention.

FIG. 6 is a schematic configuration diagram showing another example of the identification landing device.

FIG. 7 is a schematic configuration diagram showing an improved example of the identification attachment device.

FIG. 8 is an explanatory diagram for explaining a problem that may occur in the improved example.

FIG. 9 is a schematic configuration diagram showing a further improved example of the improved example.

FIG. 10 is a schematic configuration diagram showing an improved example different from FIG. 9;

FIG. 11 is a schematic configuration diagram showing a further improved example of the improved example of FIG. 9;

FIG. 12 is a schematic configuration diagram showing an improved example different from FIG. 7;

FIG. 13 is a graph showing a relationship between a bias supply time to a heating roller and a bias potential.

FIG. 14 is a table showing an example of a typical elastic material composed of nonpolar molecules and a typical elastic material composed of polar molecules.

FIG. 15 is a graph showing an example of the relationship between temperature and volume resistivity in each elastic material having a nonpolar molecular structure.

FIG. 16 is a graph showing an example of the relationship between the temperature and the volume resistivity of each elastic material having a polar molecular structure.

FIG. 17 is a schematic configuration diagram of a printer according to the first embodiment.

FIG. 18A is a cross-sectional view illustrating a schematic configuration of a fixing device of the printer. (B) is a longitudinal sectional view showing a schematic configuration of the identification attachment device.

FIG. 19 is a cross-sectional view showing a modified example of the identification attachment device.

FIG. 20 is a sectional view showing another modified example of the identification attachment device.

FIG. 21 is a cross-sectional view showing a pressing belt of the modified example device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image forming unit (image forming means) 10 photoreceptor drum 18 liquid developer (colored liquid) 20 charging device 40 developing device 51 static elimination lamp 60 transfer device 100 fixing device (image fixing device) 101 heating roller (surface moving body) 101a Conductive section 101b High resistance section 101c Halogen lamp (heating means) 102 Press roller (surface moving body) 102a Conductive section 102b High resistance section 102d, 102e Insulating section 103 Power supply 104 Separation claw 105 Press belt unit 106 Press belt (surface moving body) 106a conductive part 106b high resistance part 106d, 106e insulating part 107 drive roller 108 fixing bias roller

Claims (20)

[Claims] Moving the surfaces while contacting each other;
An image having two surface moving bodies, and a recording member on which an image is formed by a colored liquid containing a liquid carrier and chargeable colored particles is sandwiched between the two surface moving bodies to fix the image to the recording member. In the fixing device, a conductive portion made of a conductive material and a conductive high-resistance portion formed of a material having a higher electrical resistivity and fixed to the conductive portion so as to contact the other surface moving body. Are provided on both surface moving bodies, and the width of the high resistance portion of the surface moving body that is in contact with the image of the recording member sandwiched between the both surface moving bodies is set to be equal to or larger than the contact width of both high resistance parts. And an electric potential difference generating means for generating an electric potential difference between the conductive portions of both the surface moving bodies. 2. The image fixing apparatus according to claim 1, wherein a width of said high-resistance portion of said surface moving body in contact with said image is larger than said contact width. 3. The image fixing device according to claim 1, wherein
By forming both end portions in the width direction of the high-resistance portion of the surface moving body that is not in contact with the image to be thinner than other portions, the width of the high-resistance portion in the other surface moving body is reduced. An image fixing device having a contact width or more. 4. An image fixing apparatus according to claim 1, wherein an insulating portion made of an insulating material is provided in a non-contact area of the surface moving body which does not contact the image with the other surface moving body. An image fixing device, comprising: 5. The image fixing device according to claim 4, wherein the insulating portion provided on the surface moving body that does not contact the image is provided.
An image fixing device wherein the surface moving body is cut into the inside of the high resistance portion. 6. The image fixing device according to claim 1, wherein
Two insulating portions adjacent to both ends in the width direction of the high resistance portion of the surface moving body that does not contact the image are fixed on the conductive portion of the surface moving body, and the high resistance portion and the two An image fixing device wherein an insulating portion is brought into contact with the high resistance portion of the other surface moving body. 7. The image fixing device according to claim 6, wherein the two insulating portions provided on the surface moving body that is not in contact with the image are bitten into the inside of the high resistance portion of the surface moving body. An image fixing device comprising: 8. A method of moving a surface while bringing the surfaces into contact with each other.
An image having two surface moving bodies, and a recording member on which an image is formed by a colored liquid containing a liquid carrier and chargeable colored particles is sandwiched between the two surface moving bodies to fix the image to the recording member. In the fixing device, a conductive portion made of a conductive material, and a conductive high-resistance portion formed of a material having a higher electrical resistivity and fixed to the conductive portion so as to contact another surface moving body. Is provided on at least one surface moving body, the other surface moving body is made of a conductive material, and a potential difference generating means for generating a potential difference between the other surface moving body and the conductive portion is provided. An image fixing device, wherein a substrate made of a polar molecule is used as a base material of the high resistance portion. 9. An image fixing apparatus according to claim 8, wherein said high resistance portion is formed by dispersing a conductive filler in said base material. 10. An image fixing apparatus according to claim 8, wherein an elastic material is used as said base material comprising polar molecules. 11. An image fixing apparatus according to claim 10, wherein chlorosulfonated polyethylene, fluoro rubber, polysulfide rubber, urethane rubber, nitrile butadiene rubber or epichlorohydrin rubber is used as said elastic material. Image fixing device. 12. An image fixing apparatus according to claim 11, wherein epichlorohydrin rubber is used as said elastic material. 13. The image fixing device according to claim 1, wherein a conductive protective layer is provided on the surface of the high resistance portion of the surface moving body which comes into contact with the image. An image fixing device, comprising: 14. The method of claim 8, 9, 10, 11, 12 or 1.
3. The image fixing device according to 3, wherein the conductive part and the high resistance part are provided on a surface moving body that comes into contact with the image, and
An image fixing device, wherein a conductive protective layer is provided on a surface of the high resistance portion. 15. An image fixing apparatus according to claim 13, further comprising a heating means for heating the surface moving body in contact with said image. 16. An image fixing apparatus according to claim 15, wherein a fluororesin is used as a base material of said protective layer. 17. An image fixing apparatus according to claim 15, wherein said protective layer is made of a material whose main component is the same as the main component of the liquid carrier in said colored liquid. 18. A recording member in which an image is formed by a colored liquid containing a liquid carrier and chargeable colored particles is sandwiched between two surface moving bodies which move while contacting each other, and the image is formed. An image fixing method for performing a fixing step of fixing the recording member, wherein the fixing step includes the steps of:
An image fixing method using the image fixing device of any one of 0, 11, 12, 13, 14, 15, 16, and 17. 19. An image forming means for forming an image on a recording member using a colored liquid containing a liquid carrier and chargeable colored particles, and an image fixing device for fixing the image to the recording member. In the image forming apparatus, as the image fixing device, the image fixing device may be used.
An image forming apparatus comprising 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 image fixing devices. 20. An image forming step of forming an image on a recording member using a colored liquid containing a liquid carrier and chargeable colored particles, and a fixing step of fixing the image to the recording member. In the image forming method, the fixing step may include the steps of: 1, 2, 3, 4, 5, 6, 7, 8, 9, 1;
An image forming method using the image fixing device of any one of 0, 11, 12, 13, 14, 15, 16 and 17.