JP2008275794A - Intermediate transfer device and image forming apparatus with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer fixing device which prevents, in a toner image transferred and fixed on a recording medium, image quality degradation, image blur and partial fixing failure caused by variation in the areas of deformation of the toner image due to irregularities on the surface of the recording material, and offset of the toner image during deformation without exerting the influence of heat on the other member, due to heating of an intermediate transfer member, and by which the toner image is deformed with low energy, and to provide an image forming apparatus with the device. <P>SOLUTION: The intermediate transfer device is configured such that a toner image formed on an image carrier 3 is transferred onto the movable intermediate transfer member 2 and after that, the toner image on the intermediate transfer member 2 is further transferred before the toner image is transferred and fixed or transferred to a recording medium P. The intermediate transfer device includes: an intermediate transfer body 13 for supporting the toner image; a heating means 15 for heating the toner image; and a pressure-deforming means 16 for deforming the toner image from its surface under pressure. A heating area H which is located at an upstream side and where the toner image is heated, is wider than a deforming area F which is located at the downstream side of the heating area, and where the toner image is deformed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer. More specifically, a toner image formed on an image carrier is transferred or transferred and fixed to a recording material such as paper using an intermediate transfer member. The present invention relates to an image forming apparatus to be fixed on a recording medium later using a fixing unit.

2. Description of the Related Art Conventionally, various types of image forming apparatuses that transfer or transfer and fix using an intermediate transfer member and then fix the recording member using a fixing unit have been proposed (see, for example, Patent Documents 1 to 3).
In Patent Document 1, a belt-shaped image carrier, an endless intermediate transfer belt arranged in contact with the image carrier, and a toner image transferred to the intermediate transfer belt are melted. A heating roller that heats and melts above the temperature, a support roller that supports the intermediate transfer belt on the downstream side of the heating roller, and a pressure roller that is pressed against the intermediate transfer belt, the pressure roller and the intermediate transfer belt, An image forming apparatus is disclosed in which a toner image on an intermediate transfer belt is transferred and fixed to a transfer material (recording member) fed between the two.
In Patent Document 2, a toner image on an image carrier is transferred onto a belt-like intermediate transfer member, and the toner image on the intermediate transfer member is transferred between a heating roller and a pressure roller via the intermediate transfer member. Before reaching the pressure-fixing nip, the belt is heated by a sheet heater functioning as an image forming substance integration means provided on the inner surface of the intermediate transfer member, and the toner image is combined by softening or melting. An image forming apparatus is disclosed in which at least a part is bonded and integrated, and the integrated toner image is transferred and fixed to a recording medium at a fixing nip portion.
Further, Patent Document 3 includes an image carrier that carries an image forming substance and an image forming substance integration unit that integrates the image forming substance on the image carrier, and is integrated by the integration unit. There has been disclosed a transfer fixing apparatus for transferring and fixing an unfixed image on a recording medium by a transfer fixing unit.
This transfer fixing device is provided with a tackifier for imparting adhesiveness to the surface of the transfer fixing unit that is in contact with the toner recording body integrated by the image forming substance integration means, on the upstream side of the recording medium conveyance direction. . This tackifier is configured to impart tackiness by radiant heat or to impart tackiness by applying a fixing aid.
Japanese Patent No. 3528371 Japanese Patent Laid-Open No. 2001-13798 JP 2005-266304 A

However, in a general image forming apparatus, a toner image on a recording body is heated and pressed by a fixing device. At this time, the toner is deformed along the unevenness of the fibers existing on the surface of the recording body.
FIG. 12 is a schematic diagram showing a state in which a toner image is transferred onto a rough recording medium and then fixed by a fixing device in the prior art. When the toner image is transferred to the recording medium and then fixed by the fixing device, the toner area ratio slightly increases. However, in the case of a rough recording medium, the deformation is smaller because the pressure deformation is a convex portion. Therefore, it is necessary to increase the toner amount in order to satisfy the target image density in the case of a recording medium having a rough surface.
As described above, the deformation rate of the toner differs depending on the unevenness of the fiber, and the deformation rate of the convex portion increases. As described above, particularly in the case of a recording medium having a rough surface, the influence of this influence causes variations in the area of the toner image after pressure fixing, resulting in a decrease in graininess.
In addition, the toner in the concave portion of the fiber is not in contact with the pressure member or has a small applied pressure, so the deformation is small, the surface property of the toner at the concave and convex portion is different, and uneven gloss is caused and the image quality is lowered. There's a problem.
Also in the above-described transfer fixing device of Patent Document 1, the toner image on the intermediate transfer belt before being transferred to the recording medium is heated to a temperature equal to or higher than the melting temperature of the toner by a heating roller, and transferred to the recording medium in a state where the entire toner is deformed. Is done.
Therefore, the pressure at the fixing nip during transfer fixing makes it easier for the toner to deform due to the influence of the unevenness of the paper fibers present on the surface of the recording medium, the deformation area of the convex portion increases, and the pressurizing force increases at the concave portion. The deformation area is reduced without much transmission. As a result, the toner image has a large area variation, causing irregularities in graininess, uneven glossiness, and the like, resulting in a problem that the image quality deteriorates.
Similarly, in the transfer fixing device of Patent Document 2, the entire toner image is heated and deformed, the viscosity of the entire toner is lowered, and the height of the toner changes by about 40 to 80% when fixing to the recording medium. As a result, unevenness of the surface of the recording medium causes variations in the area of the toner image, and the image quality is likely to deteriorate.
Further, in the transfer fixing device of Patent Document 3, after the image forming substance on the image carrier is heated, the temperature of the surface in contact with the image carrier is made lower than the temperature of the surface in contact with the recording medium, or The fixing agent is used to impart viscosity to the surface where the image-forming substance comes into contact with the recording medium, making it difficult for the image-forming substance to deform due to irregularities on the surface of the recording medium, and the spread of the area during transfer fixing varies. Has been reduced.

The transfer and fixing devices described in Patent Documents 1 to 3 adopt a thermal fixing method in which toner on a recording medium is heated and melted and fixed by pressurization from the viewpoint of fixing speed, fixed image quality, and the like. . However, the fixing performance is greatly influenced by the surface properties of the recording medium. In the case of a medium having a rough surface, in order to satisfy the fixing property, it is necessary to increase the heating temperature or to increase the pressure of the transfer fixing unit to the recording medium.
When the temperature is raised, the temperature of the intermediate transfer member also rises, the heat moves to the image carrier, and the temperature of the image carrier rises. This temperature rise raises the temperature of the member in the vicinity of the image carrier and affects its performance.
For example, problems such as aggregation or fixation of toner in the developing device or the cleaning device occur. Further, when the pressure applied during transfer fixing is increased, the durability of the intermediate transfer member is lowered.
Further, the surface of the toner image which is deformed before being brought into contact with the recording medium and transferred to the recording medium is in a smooth state because the surface of the intermediate transfer body is transferred. However, when the surface of the recording body is rough, an image having a large gloss difference between the smooth image portion and the surface of the recording body is obtained.
Further, in the transfer fixing device of Patent Document 3, in order to deform the toner image on the intermediate transfer member, the rotating member facing the intermediate transfer member is heated to melt the toner image. However, the adhesive force between the toner image and the member is likely to be offset to the member on which the toner image is heated because the higher temperature member has a higher adhesive force with the toner.
Accordingly, an object of the present invention is to reduce the image quality or blur the image that occurs when the toner image transferred and fixed on the recording medium has a variation in the deformation area of the toner image due to irregularities on the surface of the recording medium. A transfer fixing device that prevents a typical fixing failure, prevents an offset when the toner image is deformed without affecting other members by heating the intermediate transfer member, and deforms the toner image with low energy An image forming apparatus is provided.

In order to solve the above problems, the invention described in claim 1 includes a secondary intermediate transfer member that supports a toner image transferred from an image carrier through a primary intermediate transfer member, and the secondary intermediate transfer member. In an intermediate transfer device for transferring and fixing or transferring a toner image from a transfer member to a recording member, heating means for heating the toner image on the secondary intermediate transfer member, and pressure deformation means for pressure-deforming the toner image And the heating area for heating the toner image by the heating means is wider than the deformation area formed by the pressure deformation means provided on the downstream side.
According to a second aspect of the present invention, a secondary intermediate transfer member that supports a toner image transferred from an image carrier through a primary intermediate transfer member is provided, and the toner image is transferred and fixed from the secondary intermediate transfer member to a recording member. The intermediate transfer apparatus includes a heating unit that heats the toner image on the secondary intermediate transfer member, and a pressure deformation unit that pressurizes and deforms the toner image, and is opposed to the pressure deformation unit. A rotating body as the secondary intermediate transfer member constituting the toner image pressurizing and deforming portion is disposed, and the rotating body includes the heating unit, and the diameter of the rotating body is larger than the diameter of the pressing and deforming unit. It is characterized by.
The invention of claim 3 is characterized in that the rotating body is a roller.
The invention of claim 4 is characterized in that the rotating body is a belt.
According to a fifth aspect of the invention, the secondary intermediate transfer member is a belt supported by a plurality of rollers including a heating roller, and a winding angle of the belt with respect to the heating roller is a toner image on the secondary intermediate transfer member. It is characterized in that it is wider than the deformation angle for pressure-deforming and at most 180 degrees or less.
The invention according to claim 6 is characterized in that the pressurizing and deforming means holds a flat surface which does not rotate and faces the second intermediate transfer member.
The invention of claim 7 is characterized in that at least two of the pressure deformation means are provided.
According to the eighth aspect of the present invention, an electrostatic latent image is formed on the surface of the photosensitive member, a visible image is formed by toner development, the visible image is transferred onto an intermediate transfer device, and transferred to an overlaid state. 8. An image forming apparatus that fixes the transferred composite color image onto a recording medium from a paper feeding / conveying unit at a timing, and discharges the combined color image as the intermediate transfer device. An image forming apparatus to which the intermediate transfer device according to any one of the items is applied.
According to the ninth aspect of the present invention, an electrostatic latent image is formed on the surface of the photosensitive member, a visible image is formed by toner development, the visible image is transferred onto the primary intermediate transfer member, and is brought into a superimposed state. The primary-transferred composite color image is secondarily transferred onto the secondary intermediate transfer body by electrostatic force, and the secondary-transferred composite color image is transported onto the tertiary transfer body, and is fed in time. 8. The intermediate according to claim 1, wherein the secondary intermediate transfer body is used as an intermediate transfer body in an image forming apparatus that fixes and discharges a composite color image thirdarily transferred onto a recording body from a paper / conveyance unit. An image forming apparatus to which the transfer device is applied is characterized.

According to the present invention, a toner image is deformed on a smooth intermediate transfer member, and the toner image is deformed on the deformed intermediate transfer member by heating and pressurizing the transferred toner image from the intermediate transfer member to the recording member. Can be efficiently transformed.
In order to deform the toner image, it is necessary to reach a temperature at which the toner image melts at the time of deformation. However, according to the present invention, the toner image is instantaneously formed because of a wide heating area without being affected by heat to other members. Rather than providing the necessary heat, the heat can be applied over time at a low temperature, and the temperature can be set to a predetermined temperature efficiently.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing the configuration of a main part of a tandem type color copying machine which is an image forming apparatus to which an intermediate transfer apparatus according to the present invention can be applied. FIG. 2 is a schematic configuration diagram showing a first embodiment of an intermediate transfer device mounted on the image forming apparatus of FIG. FIG. 3 is a schematic configuration diagram for explaining a toner heating area and a deformation area in the intermediate transfer apparatus of FIG.
A tandem type color copying machine A which is an image forming apparatus shown in FIG. 1 has an image forming unit 1 at the center of the apparatus main body, an intermediate transfer device 12 as a secondary intermediate transfer member, and a sheet P feeding below it. A sheet feeding cassette 19 constituting the section 1B and conveying sections 20, 21, and 22 for taking out and feeding the recording medium from the sheet feeding section are provided.
An intermediate transfer belt 2 serving as a primary intermediate transfer body having a transfer surface extending in the horizontal direction is disposed in the image forming unit 1, and the intermediate transfer belt 2 is stretched between a driving roller 9 and a driven roller 10. It can be rotated in the direction of arrow B. On the transfer surface of the intermediate transfer belt 2, drum-shaped photoconductors (image carriers) 3Y, 3M, 3C, and 3B are juxtaposed at intervals along the moving direction of the intermediate transfer belt 2.
These drum-shaped photoconductors (image carriers) 3Y, 3M, 3C, and 3B (hereinafter simply referred to as photoconductor 3 unless otherwise specified) have colors (yellow, magenta, cyan) that are complementary to the color separation color. , Black), a latent image is formed on the surface using toner as an image forming substance.

Each photoconductor 3 is rotatable in the same direction (counterclockwise direction in FIG. 1). Around them, charging devices 4Y, 4M, 4C, and 4B (hereinafter, simply referred to as charging device 4 if not specified) used for executing image forming processing are arranged.
Around each photosensitive member 3, writing devices 5Y, 5M, 5C, and 5B (hereinafter, simply referred to as writing device 4 if not specified) as optical writing means are arranged. Around each photosensitive member 3, there are further developing devices 6Y, 6M, 6C, 6B (hereinafter simply referred to as developing device 6 if not specified) and primary transfer rollers 7Y, 7M, 7C, 7B (hereinafter, referred to as “developing device 6”). A cleaning device 8Y, 8M, 8C, and 8B (hereinafter simply referred to as the cleaning device 8 if not specified) are arranged, respectively.
Each developing device 6 stores color toners corresponding to colors to be developed. A belt cleaning device 11 for cleaning the surface of the intermediate transfer belt 2 is provided at a position facing the driven roller 10.
In addition, an intermediate transfer device 12 serving as a secondary intermediate transfer unit is disposed at a position facing the driving roller 9, and a secondary transfer roller 14 is provided to provide an intermediate transfer belt 2 and a secondary intermediate transfer belt (secondary intermediate transfer member). ) To form the secondary transfer portion T2. Further, a voltage is applied to the secondary transfer roller 14 between the secondary transfer roller 14 and the driving roller 9 so as to generate an electric field in order to transfer the toner.

The secondary intermediate transfer belt 13 includes a secondary transfer roller 14, a heating roller 15, and a tertiary transfer roller 18 so as to be stretched and rotated. A cleaning device 29 is disposed in the vicinity of the secondary intermediate transfer belt 13 facing the secondary transfer roller 14.
The tertiary transfer roller 18 forming the tertiary transfer device has a pressure roller 17 disposed at a position opposed to the secondary transfer belt 13 via the secondary intermediate transfer belt 13, and the pressure roller 17 is tertiary transferred by a pressure unit (not shown). A tertiary transfer portion T3 that pressurizes the roller 18 and transfers the toner image to the recording material P is formed.
The heating roller 15 is in pressure contact with the pressure deformation roller 16 that deforms the toner disposed at the opposing position via the secondary intermediate transfer belt 13, and pressurizes the heating roller 15 by a pressing means (not shown). The heating roller 15 and the pressure deformation roller 16 form a toner deformation portion G.
The heating area H (FIG. 3) by the heating roller 15 is the same area (matches) as the deformation area F (FIG. 3) by the pressure deformation roller 16 or starts from a position upstream from the deformation area F (positioned upstream). Slipped). Bringing the heating area H upstream has an effect that the toner image is melted and easily deformed before the toner image enters the toner deformation portion G. Further, if the heating area H is made wider than the deformation area F, heat can be applied to the toner image, and there is an effect of facilitating melting.

In the tertiary transfer portion T3, the applied pressure is set to ² to 5 kgf / cm ² . In the deformation part G, the applied pressure is set to 0.5 to 3 kgf / cm ² . In the deformed portion G, the toner image is deformed by heat and pressure, so that the surface pressure can be made lower than the deformation due to pressure alone.
The recording material P is fed using a feed roller 20, a transport roller 21, and a registration roller 22 that are transport units so as to be transported from the paper feed cassette 19 to the tertiary transfer unit T 3. After passing through the tertiary transfer portion T3, the recording material P is conveyed to the fixing device 26. The fixing device 26 uses a fixing roller system.
The fixing roller 27 includes a halogen heater (not shown). A pressure roller 28 facing the fixing roller 27 presses the fixing roller 27. The fixing roller 27 is controlled to a predetermined temperature, and heats and presses the conveyed recording material P at a pressure contact portion between the fixing roller 27 and the pressure roller 28.
The fixing roller 27 has an elastic layer on a metal core and is provided with a silicon rubber layer of 0.1 to 0.5 mm. Furthermore, a release agent such as silicone oil is applied to the surface to improve the releasability, or a fluorine resin layer is added. Here, the fluororesin layer uses a 10 μm PFA tube in order to make the surface hardness low.
Although the silicon layer alone has a low hardness, the use of a thin layer fluorine-based resin is effective in view of its durability. The low hardness mentioned here is a microhardness. For example, in the universal hardness at the use temperature, it is preferably 1 N / cm ² or less at an approach amount of 20 μm corresponding to the roughness of the recording medium. This has the effect of causing the toner in the thin layer to follow the irregularities of the recording medium.

The operation of the color copying machine A will be described. When the color copying machine A starts an image forming operation, the surface of the photoreceptor 3Y is uniformly charged by the charging device 4 when a full-color image is formed. Optical writing by the writing device 5 is performed on the charging surface based on image information from the image reading unit, and an electrostatic latent image corresponding to yellow is formed there.
The electrostatic latent image is developed by a developing device 6 containing yellow toner to become a toner image (visible image). The toner image is transferred to the intermediate transfer belt 2 by a primary transfer roller 7 to which a predetermined bias is applied. Primary transfer is performed on the top.
Similarly, toner images of corresponding colors are formed on the respective photoreceptors 3M, 3C, and 3B corresponding to magenta, cyan, and black, and the toner images of the respective colors are sequentially superimposed on the intermediate transfer belt 2. Primary transfer to the state.
The toner remaining on each photoconductor 3 after the primary transfer is removed by each cleaning device 8. Further, after the transfer of each toner image, the potential of each photoconductor 3 is neutralized by a neutralizing lamp (not shown) and initialized, and is prepared for the next image forming process.

A composite color image (unfixed image) primarily transferred onto the intermediate transfer belt 2 in a superimposed state is applied between a driving roller 9 and a secondary transfer roller 14 from a secondary bias applying unit (not shown). Secondary transfer (including superposition of AC, pulses, etc.) is secondary-transferred to the secondary intermediate transfer belt 13 side by electrostatic force at the secondary transfer position T2.
The toner image conveyed to the secondary intermediate transfer belt 13 is conveyed between the heating roller 15 and the pressure deformation roller 16 (toner deformation portion G). The heating roller 15 is controlled to a predetermined temperature.
The conveyed toner image is heated by the heat of the heating roller 15 and is deformed by the pressure of the pressure deformation roller 16, so that the area ratio of the toner image is increased. Thereafter, the sheet is conveyed between the pressure roller 17 and the tertiary transfer roller 18 (third transfer portion T3).
The paper feed roller 20 of the paper feed cassette 19 of the paper feed / conveyance section rotates in accordance with the timing at which the toner image enters the nip portion of the tertiary transfer portion T3, and is separated one by one from the uppermost paper of the recording medium P. Paper is fed.
The fed recording material P is transported by the transport roller pair 21 to the resist roller pair 22 in a stopped state and temporarily stops. The recording material P has its oblique feed (skew) corrected by abutting the leading end against the registration roller pair 22. Thereafter, the toner is fed toward the tertiary transfer portion T3 at an accurate timing coincident with the leading edge of the toner image on the secondary intermediate transfer belt 13.
The toner image deformed by the toner deforming portion G and the recording material P are conveyed while being pressed and simultaneously pressed by the tertiary transfer portion T3. The recording material P after the toner image is transferred is conveyed to the fixing device 26. Thereafter, the paper is discharged to a paper discharge tray (not shown).

The secondary intermediate transfer belt 13 has, for example, a two-layer structure, an inner base layer is formed of polyimide resin, and silicon rubber having a thickness of 0.05 to 0.5 mm is formed as an elastic layer on the outer side thereof. .
Since the secondary intermediate transfer belt 13 is heated from the back surface of the secondary intermediate transfer belt 13, the heating efficiency increases as the layer becomes thinner. In this case, however, it is necessary to consider the belt life and durability. There is.
The elastic layer on the belt surface layer allows the toner image to follow the surface of the recording medium P in the tertiary transfer section T3 for transferring the deformed toner image to the recording medium P, and ensures transferability in the tertiary transfer section. It is effective to do.
For example, in order to transfer a thin toner image onto a rough recording medium, the pressurizing force of the tertiary transfer portion T3 is increased, or the secondary intermediate transfer belt 13 is further heated to soften the toner image. It is effective. However, the durability of the member is reduced due to high pressurization, the energy consumption is increased due to high-temperature heating, and further, the heat is transferred to the primary intermediate transfer belt 2 through the secondary intermediate transfer belt 13, and the temperature of the image forming unit 1 is increased. This causes problems such as image flow and blocking.
In order to prevent such a problem, a member that follows the surface irregularities of the recording material P is preferable. Here, the hardness measured in a region where the surface hardness of the member is wider than the distance between the recording fiber fibers as in the conventional JIS hardness cannot cope with the followability but can be handled with the universal hardness which is microscopic hardness. Therefore, HU 1.0 N / mm ² or less (penetration amount 20 μm) is used as the member surface layer hardness of the secondary intermediate transfer belt 13 in contact with the recording medium P.
Although the surface layer of the secondary transfer belt 13 is an elastic layer here, the elastic layer is made of a fluorine-based resin material having a thickness of 5 to 20 μm as a surface layer in order to stably release the toner image and prevent deterioration. It is also effective to form (tube) with some PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin) or PTFE (tetrafluoroethylene copolymer resin).

2 and 3 show the periphery of the secondary intermediate transfer belt of the secondary intermediate transfer device mounted on the image forming apparatus of FIG. The pressure deformation roller 16 of the toner deformation portion G has a metal core metal surface layer made of PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin) or PTFE (tetrafluoroethylene co-polymer), which is a fluorine resin material. A layer coated with a polymer resin) is formed.
Here, as described above, the secondary intermediate transfer device 12 forms the heating region H from the contact of the secondary intermediate transfer belt 13 as the secondary intermediate transfer member with the heating roller 15 to the toner deformation portion G. After the secondary intermediate transfer belt 13 is heated through the heating roller 15 and the toner image is heated by the heat, the toner image is deformed by heat and pressure by the deformation region F of the heating roller 15 and the pressure deformation roller 16.
The heating area H is preferably set to an area longer than the time during which the secondary intermediate transfer belt 13 can transfer heat to the secondary intermediate transfer belt 13 through the heating roller 15. Thereby, the heating temperature of the toner image can be set to a softening temperature necessary for sufficiently deforming, and the toner image can be deformed more efficiently.

Further, by setting the heating area H wider than the deformation area F, more heat can be applied to the toner image, and the softened state necessary at the time of deformation can be obtained. Further, the temperature of the toner image is such that the temperature on the contact surface side with the secondary intermediate transfer belt 13 is higher than the temperature on the contact surface side with the pressure deformation roller 16.
For this reason, the toner image pressurized by the toner deforming portion G has an effect of preventing the toner from being offset to the pressure deforming roller 16 because the adhesion force to the secondary intermediate transfer belt 13 having a high temperature is increased.
Thereafter, the toner image that has passed through the toner deforming portion G is conveyed to the tertiary transfer portion T3, and the toner image is transferred to the recording material P by contact pressure with the recording material P. This transfer utilizes the effect that the toner image is softened by the heat applied to the toner image upstream, so that it easily adheres to the recording material P.
In order to obtain this effect higher, if the moving time from the tertiary transfer portion T3 to the deformation portion G is shortened, the heat radiation from the toner image can be reduced, and the toner temperature is maintained without lowering, so that the adhesion is further increased. The effect which it is easy to do is acquired.
When creating a toner image, obtaining a necessary image density is one of the goals. The necessary image density varies depending on the surface roughness of the recording material P, and the larger the surface roughness, the more toner is required.
The reason for this is that, as described above, when a toner image is transferred to the recording medium P, fine irregularities on the surface of the recording medium are affected, and the toner enters into the concave portions, so that the toner area ratio is low in a 100% solid image. It is in.

As shown in FIG. 12, conventionally, when a toner image is transferred to a recording medium and then fixed by a fixing device, the toner area ratio is slightly increased. The deformation rate is small. Therefore, it is necessary to increase the toner amount in order to satisfy the target image density in the case of a rough surface recording medium.
For example, when a 100% solid image is created with a toner particle size of 6 μm and a toner amount of 0.4 mg / cm ² , the toner area ratio is 90% in a recording medium having a high smoothness (Rz 2 μm) after the toner image transfer. .
On the other hand, it is 80% for a recording medium with poor smoothness (Rz 50 μm). The area after deformation by the fixing device was 97% highly smooth and 82% low smooth, and the deformation rate was small, and a toner amount of 0.5 mg / cm ² was required to obtain the target image density.

In this embodiment, since the toner is preliminarily heated and softened by the toner deformation portion G and is deformed under pressure on a smooth member, the pressure variation on the toner is reduced and the deformation of the toner is stable. It becomes. Since stable deformation is possible before transfer to the recording medium, an image can be created with the same toner amount regardless of the surface roughness of the recording medium.
In the present embodiment, the secondary intermediate transfer belt 13 has a low hardness in order to ensure transferability at the tertiary transfer portion T3. Therefore, since the surface layer of the deformation roller 16 has a higher hardness than that of the secondary intermediate transfer belt 13 so as to be further deformed in the toner deformation portion G, the deformation rate of the toner image can be increased, and the toner area ratio can be secured with a small amount of toner. can do.
So far, the intermediate transfer device using the heating roller 15 has been described. As another heating method, there is also a method of heating the toner image by causing the intermediate transfer belt 13 to generate heat by using the IH coil 23.

FIG. 4 is a schematic configuration diagram showing a second embodiment of the intermediate transfer apparatus according to the present invention. FIG. 5 is a schematic configuration diagram for explaining a toner heating area and a deformation area in the intermediate transfer apparatus of FIG.
An intermediate transfer device 12 that performs secondary intermediate transfer is disposed at a position facing the drive roller 9, and a secondary transfer roller 14 is provided and the secondary transfer portion T <b> 2 is interposed via the intermediate transfer belt 2 and the secondary intermediate transfer belt 13. Is forming.
Further, a voltage is applied to the secondary transfer roller 14 so as to generate an electric field between the secondary transfer roller 14 and the driving roller 9 in order to transfer toner. In this embodiment, the roller 15 functioning as a heating roller is used only as a support roller for the secondary intermediate transfer belt 13 here, and the IH coil 30 disposed upstream of the rollers 15 and 16 generates heat for the secondary intermediate transfer belt 13 itself. Thus, the toner image is heated.
The overall structure of the secondary transfer device 12 shown here is the same as that of the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
The heating region H (FIG. 5) can be made wider than the configuration using the heating roller 15, and the intermediate transfer belt 13 can be heated instantaneously rather than the heat conduction to the intermediate transfer belt 13 by the heating roller 15. The toner image can be heated with low energy.

FIG. 6 is a schematic configuration diagram showing a third embodiment of an intermediate transfer apparatus according to the present invention. An intermediate transfer device 12 that performs secondary intermediate transfer is disposed at a position facing the drive roller 9, and a secondary transfer roller 14 is provided and the secondary transfer portion T <b> 2 is interposed via the intermediate transfer belt 2 and the secondary intermediate transfer belt 13. Is forming.
The overall structure of the secondary transfer device 12 is the same as that of the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
In contrast to the first embodiment described above, in the third embodiment, the diameter of the heating roller 15 is made larger than the diameter of the pressure deformation roller 16. As a result, the area where the intermediate transfer belt 13 is in contact with the heating roller 15, that is, the heating region H is widened, and the amount of heat to the toner image is increased. Accordingly, the toner image is easily softened, and the deformation efficiency is increased.
An intermediate transfer belt 13 is used as an intermediate transfer member constituting the toner deforming portion. Since the intermediate transfer belt 13 is thin, it has a high thermal conductivity and easily transfers heat to the toner image. Moreover, since the shape can be changed flexibly, the component space can be kept low.
As described above, in order to uniformly deform the toner image, it is necessary to carry out heat on the smooth and stable member and efficiently transfer heat from the intermediate transfer member to the toner image. For this reason, by using the intermediate transfer belt 13 as an intermediate transfer member, the heat can be transmitted thinly and the toner image can be efficiently heated.

FIG. 7 is a schematic configuration diagram showing a fourth embodiment of an intermediate transfer apparatus according to the present invention. An intermediate transfer roller 25 as an intermediate transfer member constituting the toner image deforming portion is arranged at a position facing the drive roller 9.
The configuration around the intermediate transfer roller 25 shown here is the same as the configuration around the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
In this embodiment, an intermediate transfer roller (intermediate transfer member) 25 is used instead of the intermediate transfer belt 13. The cleaning device 29 is provided around the intermediate transfer roller 25.
The intermediate transfer roller 25 can hold the toner image stably and has little variation when the toner image is deformed. Further, the functions of the secondary transfer portion T2, the deforming portion G, and the tertiary transfer portion T3 can be concentrated on the peripheral portion of one component, so that the component cost can be suppressed.
In order to uniformly deform the toner image, it is necessary to perform it on a smooth and stable member. By using the intermediate transfer roller 25, the toner image can be uniformly deformed on a smooth and stable roller.
In addition, a single roller can serve the functions of transferring a toner image from an image carrier (primary transfer belt), toner image deformation, and transferring a toner image to a recording body, and the number of parts can be reduced.
In the pressure deforming portion that pressurizes and deforms the toner image, the diameter of the rotating body (intermediate transfer roller 25) that is an intermediate transfer body that heats the toner image is large. Therefore, the toner image on the intermediate transfer member enters the nip portion with the opposing rotary member (pressure deformation roller 16) that pressurizes and deforms the toner image. Increases the time (distance) to get heat from
If the time for applying heat to the toner image increases, a sufficient amount of heat can be applied even if the heating temperature of the rotating body (intermediate transfer roller 25) is lower than the temperature necessary for the toner to melt instantaneously.

FIG. 8 is a schematic configuration diagram showing a fifth embodiment of an intermediate transfer apparatus according to the present invention. The overall structure of the secondary transfer device 12 shown here is the same as that of the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
In the intermediate transfer device using the intermediate transfer belt 13, the winding angle of the intermediate transfer belt 13 with respect to the heating roller 15 is made larger than the nip angle in the toner deformation portion that deforms the toner image.
As a result, the area where the intermediate transfer belt 13 is in contact with the heating roller 15, that is, the heating region H is widened, and the amount of heat to the toner image is increased. Therefore, the toner image is easily softened and the deformation efficiency is increased.
The greater the angle at which the intermediate transfer belt 13 holding the toner image is wound around the rotating body (heating roller 15) that heats the toner image, the more the area where heat is transferred to the intermediate transfer belt 13, the more heat is applied to the toner image. Is easy to communicate. Here, in order to widen the heating region H, it is considered that a better effect can be obtained when the winding angle of the intermediate transfer belt 13 is 180 degrees or more.
However, in order to increase the winding angle to 180 degrees or more, it is necessary to increase the diameter of the rotating body (heating roller 15) that heats the toner image or to increase the winding angle of the intermediate transfer belt 13 using additional parts. In addition, an increase in heat consumption due to the large diameter and an increase in cost due to the additional parts become problems, which is counterproductive.

FIG. 9 is a schematic diagram showing the sixth embodiment of the intermediate transfer apparatus according to the present invention. The overall structure of the secondary transfer device 12 shown here is the same as that of the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
In the intermediate transfer device 12 using the intermediate transfer belt 13, the toner deforming portion Gf is composed of a pressure deforming roller 16 and a flat member 16f. As a result, the toner deforming portion Gf becomes wider than the toner deforming portion G in the first to fifth embodiments so far, the time for deforming the softened toner image is increased, and the deformation efficiency is increased.
Further, if the pressure deformation roller 16 is made to have a low hardness, the toner deformation portion Gf becomes wider and more easily deformed. Furthermore, after the intermediate transfer belt 13 passes through the heating region, the flat member 16f is disposed in the deformation region, thereby producing a cooling effect on the back surface of the intermediate transfer belt 13 that does not hold the toner image.
In order to efficiently press and deform the toner image on the intermediate transfer member (intermediate transfer belt 13), the toner image pressurizing and deforming means (pressurizing and deforming roller 16) faces the intermediate transfer member. A member having a flat is disposed.
As a result, the nip width constituted by the toner image pressurizing and deforming means and the member having a flat surface can be formed wider than the nip formed between the rotating bodies, and the toner image can be efficiently formed. It can be deformed.

FIG. 10 is a schematic configuration diagram showing a seventh embodiment of an intermediate transfer apparatus according to the present invention. The overall structure of the secondary transfer device 12 shown here is basically the same as that of the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
The seventh embodiment also shows an intermediate transfer apparatus having a toner deformation portion Gf as in the sixth embodiment and a heating method using an IH coil 30. Compared to the heating method using rollers, the heat energy for heating the intermediate transfer belt 13 can be reduced, and the heating area can be widened. Further, the flat member 16f can widen the range of the toner deforming portion Gf, and the efficiency can be increased in both the heating and pressurizing regions.

FIG. 11 is a schematic configuration diagram showing an eighth embodiment of an intermediate transfer apparatus according to the present invention. The overall structure of the secondary transfer device 12 shown here is basically the same as that of the secondary transfer device 12 shown in FIG. Therefore, the same reference numerals are given to the same parts, and redundant explanations that are not necessary in the present embodiment are omitted.
Deformation efficiency is improved by providing two or more toner deforming portions G (two locations Ga and Gb in the eighth embodiment) that deform after heating the toner image on the intermediate transfer member 25. Here, the heating area is arranged upstream of the first toner deforming portion Ga to facilitate the deformation of the toner image.
When the above-described intermediate transfer device is applied to an image forming apparatus, the toner image is deformed on a smooth intermediate transfer member, and the deformed toner image is applied to the recording member, and the transferred toner image is heated from the intermediate transfer member and pressurized. The toner image can be efficiently deformed on the deformed intermediate transfer member.

1 is a schematic configuration diagram illustrating a configuration of main parts of a tandem type color copying machine that is an image forming apparatus to which an intermediate transfer apparatus according to the present invention can be applied. FIG. 2 is a schematic configuration diagram illustrating a first embodiment of an intermediate transfer device mounted on the image forming apparatus of FIG. 1. FIG. 3 is a schematic configuration diagram illustrating a toner heating area and a deformation area in the intermediate transfer device of FIG. 2. FIG. 3 is a schematic configuration diagram illustrating a second embodiment of an intermediate transfer device according to the present invention. FIG. 5 is a schematic configuration diagram illustrating a toner heating area and a deformation area in the intermediate transfer device of FIG. 4. It is a schematic block diagram which shows 3rd Embodiment of the intermediate transfer apparatus by this invention. FIG. 6 is a schematic configuration diagram illustrating a fourth embodiment of an intermediate transfer device according to the present invention. FIG. 10 is a schematic configuration diagram illustrating a fifth embodiment of an intermediate transfer device according to the present invention. It is a schematic block diagram which shows 6th Embodiment of the intermediate transfer apparatus by this invention. It is a schematic block diagram which shows 7th Embodiment of the intermediate transfer apparatus by this invention. It is a schematic block diagram which shows 8th Embodiment of the intermediate transfer apparatus by this invention. FIG. 6 is a schematic diagram illustrating a state of fixing a toner image onto a rough recording medium and a subsequent fixing device in the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image formation part, 1B paper feed part, 2 primary intermediate transfer body (primary intermediate transfer belt), 3 image carrier (photosensitive body), 6 developing device, 7 primary transfer roller, 12 intermediate transfer apparatus (secondary Intermediate transfer device), 13 Intermediate transfer body (secondary intermediate transfer belt), 14 Secondary transfer roller, 15 Rotating body (heating means, heating roller), 16 Rotating body (pressure deformation means, pressure deformation roller), 17 Pressure roller, 18 tertiary transfer roller, 25 rotating body (intermediate transfer roller), 26 fixing device, 30 IH coil, A image forming apparatus (color copying machine), F deformation region, G toner deformation portion, Ga first toner Deformation part, Gb second toner deformation part, H heating area, T2 secondary transfer part, T3 tertiary transfer part,

Claims (9)

  An intermediate transfer device that includes a secondary intermediate transfer member that supports a toner image transferred from an image carrier through a primary intermediate transfer member, and that transfers and fixes or transfers the toner image from the secondary intermediate transfer member to a recording member. And a heating means for heating the toner image on the secondary intermediate transfer member, and a pressure deformation means for pressure-deforming the toner image, and an area of a heating region for heating the toner image by the heating means is An intermediate transfer device characterized in that the intermediate transfer device is wider than a deformation region by the pressure deformation means provided on the downstream side. In the intermediate transfer apparatus that includes a secondary intermediate transfer body that supports a toner image transferred from the image carrier through the primary intermediate transfer body, and that transfers and fixes or transfers the toner image from the secondary intermediate transfer body to the recording body. A heating means for heating the toner image on the next intermediate transfer member, and a pressure deformation means for pressure-deforming the toner image;
A rotating body as the secondary intermediate transfer member that constitutes a toner image pressurizing and deforming portion is disposed opposite to the pressure deforming means, and the rotating body includes the heating means, and the diameter of the rotating body is An intermediate transfer device having a diameter larger than that of the pressure deformation means.   The intermediate transfer device according to claim 2, wherein the rotating body is a roller.   The intermediate transfer apparatus according to claim 2, wherein the rotating body is a belt.   The secondary intermediate transfer member is a belt supported by a plurality of rollers including a heating roller, and a winding angle of the belt with respect to the heating roller is used for pressure-deforming the toner image on the secondary intermediate transfer member. 2. The intermediate transfer device according to claim 1, wherein the intermediate transfer device is wider than the deformation angle and at most 180 degrees or less.   The intermediate transfer device according to any one of claims 1 to 5, wherein the pressurizing and deforming unit holds a flat surface that does not rotate and faces the intermediate intermediate transfer member. .   The intermediate transfer apparatus according to claim 1, further comprising at least two pressure deformation units.   An electrostatic latent image is formed on the surface of the photoconductor, a visible image is formed by toner development, the visible image is transferred onto an intermediate transfer device, and the synthesized color image transferred in an overlapping state is timed. The intermediate transfer device according to claim 1, wherein the intermediate transfer device is an image forming apparatus that fixes the transferred composite color image on a recording body from a paper feeding / conveying unit and discharges the composite color image. An image forming apparatus to which a transfer device is applied.   An electrostatic latent image is formed on the surface of the photosensitive member, a visible image is formed by toner development, the visible image is transferred onto a primary intermediate transfer member, and a composite color image that is primarily transferred in an overlapping state is formed. Secondary transfer is performed on the secondary intermediate transfer body by electrostatic force, and the secondary transferred composite color image is transported onto the tertiary transfer body, and the recording medium is fed from the paper feeding / conveying unit in time. 8. An image forming apparatus for fixing and discharging a composite color image that has undergone tertiary transfer, wherein the intermediate transfer device according to claim 1 is applied as the secondary intermediate transfer member. Image forming apparatus.

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