JP2007065217A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a transfer fixing device, that obtains a high quality image by providing at least an intermediate transfer member, chosen between the intermediate transfer member and a transfer fixing body, with a heat circulation means (heat circulation device), thereby relieving the temperature rise of the intermediate transfer member, and that greatly saves energy without using power in order to relieve the temperature increase of the intermediate transfer member. <P>SOLUTION: The heat circulation device 36 is configured such that the rear surfaces of the upstream and downstream portions A and B of an intermediate transfer belt 2 are brought into contact with the odd number of roller-like rotation bodies, namely heat conductive rollers 28a, 28b and 28c which are rotatable and have high heat conductivity, and are connected in contact with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, or a multi-function machine having a plurality of functions, and more particularly, a transfer fixing device that simultaneously performs transfer and fixing on a recording medium. The present invention relates to an image forming apparatus.

  Conventionally, in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, a plotter, or a multi-function machine, an electrostatic latent image is formed on a photoconductor as an image carrier and developed with dry toner. The toner image is electrostatically transferred to, for example, a sheet-like recording medium such as paper, and an unfixed image transferred and carried on the paper is heated and fixed to obtain a copy or a recorded material. Image forming methods are widely used. However, in these image forming apparatuses and methods, due to the unevenness of the surface of the recording medium, the recording medium and the photoconductor do not completely adhere to each other, resulting in a non-uniform gap, disturbing the transfer electric field, There are problems such as coulomb repulsion, and the moisture content of the recording medium changes depending on the environmental conditions such as the temperature and humidity where the image forming apparatus is placed, and the electrical resistance of the recording medium changes, thereby disturbing the image. It sometimes occurred. Hereinafter, in order to make the present invention easier to understand, the transition and progress of the prior art will be described in some detail in the past.

  To solve this problem, a multicolor toner image is electrostatically superimposed and transferred from an image carrier such as a photoconductor to an intermediate transfer member, and the toner image is melted on the intermediate transfer member. An image forming apparatus has been proposed in which a toner image is fixed and transferred at the same time to a recording medium in a predetermined transfer simultaneous fixing unit to obtain a color copy (for example, see Patent Document 1).

  In such an image forming apparatus proposed in Japanese Patent Laid-Open No. 10-63121 (Patent Document 1), the intermediate transfer member is heated as much as the toner heating time, and from the inner surface side of the intermediate transfer member to the entire layer thickness direction. Due to the heating, the image carrier is also heated when the intermediate transfer member next enters the primary transfer region, causing problems such as toner fixation.

In order to solve the above problems, measures have been proposed in which an intermediate transfer member is cooled in the middle using a cooling fan, and a temperature rise is prevented by a heat sink or the like. In addition, between the image forming position on the belt-shaped image carrier and the transfer simultaneous fixing unit, the belt toward the image forming unit and the belt toward the transfer simultaneous fixing unit are brought into contact with each other to perform energy exchange, thereby reducing energy loss. An image forming apparatus including a heat reflux device for reducing the temperature is disclosed (for example, see Patent Document 2).
However, in any case, in the image forming apparatus using the transfer fixing method in which the intermediate transfer member is directly heated, it is difficult to reduce the temperature of the intermediate transfer member even if the above cooling means is used. Image deterioration due to changes in physical characteristics and toner fixation becomes a problem. Furthermore, the heat cycle in which the intermediate transfer member is heated and cooled repeatedly is repeated, which is very disadvantageous from the viewpoint of durability and thermal efficiency. Moreover, it leads to the increase in the cost of a cooling device and the power consumption by a cooling device.

In response to the above problem, an image forming apparatus that does not directly heat the intermediate transfer member has been devised (for example, see Patent Document 3). In particular, in an electrophotographic image forming apparatus described in Japanese Patent Application Laid-Open No. 2004-145260 (Patent Document 3), an unfixed toner image formed on an intermediate transfer member is transferred to a transfer fixing roller (transfer fixing member) and transferred. By heating and melting unfixed toner on the fixing roller, and simultaneously transferring and fixing the toner image on the recording medium at a nip formed by a pressure roller (pressure body) that is in pressure contact with the transfer fixing roller, A transfer fixing device for forming a fixed image is disclosed.
According to this image forming apparatus, since the intermediate transfer member is not directly overheated, heat transfer to the intermediate transfer member can be suppressed, so that changes in physical properties of the photosensitive member and toner fixation can be suppressed, A high-quality fixed image can be formed. In addition, the durability of the photoreceptor and the intermediate transfer member can be improved. Further, since the time for heating the toner can be lengthened by the transfer and fixing method, low-temperature fixing is possible and the warm-up time can be shortened, so that energy saving is improved.

Japanese Patent Laid-Open No. 10-63121 JP 2002-99158 A JP 2004-145260 A JP 2002-244450 A

However, even in the transfer fixing apparatus that does not directly heat the intermediate transfer member as described above, the contact portion between the intermediate transfer member and the transfer fixing member (hereinafter referred to as “secondary transfer nip portion”) is used. There is a problem in that the temperature of the intermediate transfer member rises and image deterioration is caused by physical characteristics of the photosensitive member and toner fixation.
Therefore, as a cooling means of the transfer fixing device that does not directly heat the intermediate transfer member, a cooling fan that blows air to the intermediate transfer belt as the intermediate transfer member is used, and the transfer fixing unit is attached to the unfixed belt-like transfer fixing member. There has been proposed a thermal image forming apparatus that includes a heat reflux device that connects the upstream and downstream of the printer with a roller, a belt, or the like to promote heat exchange (see, for example, Patent Document 4).
However, in the image forming apparatus proposed in Japanese Unexamined Patent Application Publication No. 2002-244450 (Patent Document 4), the power consumption is increased by using a cooling fan, and the heat of the transfer fixing body that holds the toner by convection by air blowing. Since the heat efficiency is reduced due to the loss of energy, there is a problem of poor energy saving.
Furthermore, although a transfer bias is also described as means for transferring toner from the intermediate transfer member to the transfer fixing member, the transfer fixing member is made of silicone rubber because it is based on adhesive transfer. However, since it is based on bias transfer, not adhesive transfer, which has a problem in long-term stability, it always has a release layer made of a fluororesin. Therefore, in order to maintain high image quality, prevention of toner scattering from the transfer belt to the transfer fixing roller (or belt) at the front entrance of the secondary transfer nip is required. In particular, when toners are stacked in multiple layers of four colors or more and the number of times of transfer is large, transfer dust becomes a big problem in the reproducibility of one dot at a high resolution of 1200 dpi or more. This problem is a new problem that is not mentioned in the above-described prior art.

  Therefore, the present invention has been made in view of the above-described circumstances, and in an image forming apparatus including a transfer fixing device that does not directly heat an intermediate transfer member, at least one of the intermediate transfer member and the transfer fixing member. By providing a heat reflux means (heat reflux device) on the intermediate transfer member, it is possible to obtain a high quality image by reducing the temperature rise of the intermediate transfer member and to reduce the temperature rise of the intermediate transfer member. An object of the present invention is to provide an image forming apparatus provided with a transfer and fixing device that is excellent in energy saving. It is another object of the present invention to provide a high quality image by reducing the transfer dust at the secondary transfer nip portion by providing a bias applying means to the intermediate transfer body heat reflux means in contact with the intermediate transfer body.

In order to solve the above-described problems and achieve the above-described object, the invention according to each claim employs the following characteristic means / invention specific matters (hereinafter referred to as “configuration”).
According to the first aspect of the present invention, an unfixed image is formed on an image bearing member, the unfixed image is subsequently transferred to an intermediate transfer member, and then the unfixed image transferred to the intermediate transfer member is transferred to the transfer fixing member. In the image forming apparatus for simultaneously transferring and fixing to the recording medium by further pressing the transfer fixing body and the pressure body while heating the unfixed image on the transfer fixing body after And a heat reflux means for the intermediate transfer member that moves heat from the downstream portion to the upstream portion of the intermediate transfer member as viewed from the contact portion with the transfer fixing member with respect to the moving direction of the intermediate transfer member. .

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the heat transfer means for the intermediate transfer member has a thermal conductivity on each back surface of the upstream portion and the downstream portion of the intermediate transfer member. It is the structure which contacted and connected with the high member.

  According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the heat transfer means for the intermediate transfer member contacts the back surfaces of the upstream portion and the downstream portion of the intermediate transfer member with each other. It is characterized in that it is connected by contact with an odd number of roller-like rotating bodies having high heat conductivity that can rotate.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, the heat transfer means for the intermediate transfer member has a thermal conductivity on each back surface of the upstream portion and the downstream portion of the intermediate transfer member. It is the structure which was made to contact and connect with the high belt-like rotary body.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the transfer fixing member is a roller-shaped member.

  A sixth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the transfer fixing member is a belt-shaped member.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, from the downstream portion to the upstream portion of the transfer fixing member as viewed from the contact portion with the pressure member in the moving direction of the transfer fixing member. It is characterized by having a heat reflux means for a transfer fixing body that moves heat.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the heat reflux means for the transfer fixing body has thermal conductivity on each back surface of the upstream portion and the downstream portion of the transfer fixing body. It is the structure which contacted and connected the high member.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the heat fixing means for the transfer fixing member is in contact with the back surfaces of the upstream portion and the downstream portion of the transfer fixing member. It is characterized in that it is connected by contact with an odd number of roller-like rotating bodies having high heat conductivity that can rotate.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the heat reflux means for the transfer and fixing body has a thermal conductivity on each back surface of the upstream and downstream portions of the transfer and fixing body. It is the structure which was made to contact and connect with the high belt-like rotary body.

  According to an eleventh aspect of the present invention, there is provided the heat transfer means for the intermediate transfer member according to any one of claims 1 to 4 and the heat reflux means for the transfer fixing member according to any one of claims 7 to 10. And both.

  According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the first to eleventh aspects, the transfer fixing body has at least a release layer and uses a developer of four or more colors. The heat transfer means for the intermediate transfer member is electrically conductive and is applied with a bias having a polarity opposite to that of the ground or the developer.

According to the present invention, a novel image forming apparatus can be provided by solving the above-described problems. The main effects of the present invention are as follows.
According to the present invention, by including the heat transfer means for the intermediate transfer member that moves the heat from the downstream portion to the upstream portion of the intermediate transfer member as viewed from the contact portion with the transfer fixing member with respect to the moving direction of the intermediate transfer member. The heat transferred from the secondary transfer nip portion, which is the contact portion between the intermediate transfer member and the transfer fixing member, to the downstream portion of the intermediate transfer member is moved to immediately before the secondary transfer nip portion, which is the upstream portion of the intermediate transfer member. As a result, the temperature rise of the intermediate transfer member in the vicinity of the image carrier such as the photosensitive member can be mitigated, and the developer (toner) can be prevented from adhering to the intermediate transfer member.

  According to the present invention, in addition to the heat transfer means for the intermediate transfer member, heat is transferred from the downstream portion to the upstream portion of the transfer fixing member as viewed from the contact portion with the pressure member in the moving direction of the transfer fixing member. By having the heat reflux means for the transfer fixing body, the heat transferred to the downstream portion of the transfer fixing body immediately after the transfer fixing nip, which is the contact portion between the transfer fixing body and the pressure body, is transferred to the upstream portion of the transfer fixing body. By moving it immediately after the secondary transfer nip portion, the heat can be used for softening the developer (toner), and at the same time, the temperature of the secondary transfer nip portion can be lowered to further alleviate the temperature rise of the intermediate transfer member. it can.

  According to the present invention, it is possible to reduce transfer dust in the secondary transfer nip portion by providing a means for applying a bias to the intermediate transfer member heat reflux means that contacts the intermediate transfer member. With this effect, it is possible to provide an image forming apparatus that forms a high-quality fixed image and has high energy saving performance.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention (hereinafter simply referred to as “embodiments”) including the best mode for carrying out the invention, examples, and the like will be described below with reference to the drawings. In each embodiment, each modification, etc., components such as members and components having the same function and shape are described once, and the description thereof is omitted by attaching the same reference numerals. In the figure, components that are configured in a pair and do not need to be specifically distinguished and described are described by appropriately describing one of them for the sake of simplification of description. In order to simplify the drawings and the description, even if the components are to be represented in the drawings, the components that do not need to be specifically described in the drawings may be omitted as appropriate. When a constituent element such as a published patent gazette is cited and explained as it is, the reference numeral is attached with parentheses to distinguish it from that of each embodiment.

(First embodiment)
FIG. 1 shows an image forming apparatus according to a first embodiment of the present invention. First, the outline of the configuration and operation of a tandem type color copying machine 100 as an example of an image forming apparatus according to the present embodiment will be described with reference to FIG. The color copying machine 100 includes an image forming unit 1 positioned at the center of the apparatus main body, a paper feeding unit 15 positioned below the image forming unit 1, and an image reading unit (not shown) positioned above the image forming unit 1. have.

  An intermediate transfer belt 2 as an intermediate transfer member having a transfer surface extending in the horizontal direction is disposed in the image forming unit 1. On the upper surface of the intermediate transfer belt 2, a configuration for forming an image having a color complementary to the color separation color is provided. That is, a drum-shaped photoconductor as an image carrier capable of carrying an image of toner (yellow (Y), magenta (M), cyan (C), black (B)) as a developer having a complementary color relationship. 3Y, 3M, 3C, and 3B are juxtaposed along the transfer surface of the intermediate transfer belt 2.

Each of the photoconductors 3Y, 3M, 3C, and 3B is configured by a drum that can rotate in the same direction (counterclockwise direction), and around the charging device 4 that performs image forming processing in the rotation process, A writing device 5, a developing device 6, a primary transfer device 7, and a cleaning device 8 are arranged as optical writing means. The alphabets attached to these symbols correspond to the colors of the toner as in the photosensitive member 3.
Each developing device 6 accommodates each color toner. The intermediate transfer belt 2 is wound around the driving rollers 9 and 10 and the driven roller 11 and has a configuration capable of moving in the direction of the arrow in the figure at a position facing each of the photoreceptors 3Y, 3M, 3C and 3B. is doing. A cleaning device 12 for cleaning the surface of the intermediate transfer belt 2 is provided at a position facing the driven roller 11 via the intermediate transfer belt 2.

The surface of the photoreceptor 3Y is uniformly charged by the charging device 4Y, and an electrostatic latent image is formed on the photoreceptor 3Y based on the image information from the image reading unit. The electrostatic latent image is visualized as a toner image by a developing device 6Y containing yellow toner, and the toner image is primarily transferred onto the intermediate transfer belt 2 by a primary transfer device 7Y to which a predetermined bias is applied. The
The other photoconductors 3M, 3C, and 3B also form similar images only with different toner colors, and the toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 2 and superimposed. After transfer, the toner remaining on the photoreceptors 3Y, 3M, 3C, and 3B is removed by the cleaning devices 8Y, 8M, 8C, and 8B, and after the transfer, the photoreceptors 3Y, 3M, and 3C are removed by a neutralization lamp (not shown). The potential of 3B is initialized and prepared for the next imaging step.

  The paper feed unit 15 separates the paper P in the paper feed tray 14 one by one in order from the top one, and the paper feed tray 14 on which sheets P as an example of a sheet-like recording medium as a recording medium are stacked and stored. And a pair of conveyance rollers 17 for conveying the fed paper P, and a pair of registration rollers 18 for temporarily stopping the conveyed paper P and correcting the oblique deviation. ing. The registration roller pair 18 is configured such that the rollers can be brought into and out of contact with each other, and the leading end of the image held by the transfer fixing roller 22 as a transfer fixing member disposed on the downstream side thereof coincides with a predetermined position in the conveyance direction. At this timing, the sheet is fed toward a transfer fixing nip portion (hereinafter simply referred to as “nip portion”) N formed by pressure contact between the transfer fixing roller 22 and a pressure roller 34 as a pressure member.

  In the vicinity of the driving roller 9, a transfer fixing device 20 is provided. In the transfer fixing device 20, a transfer fixing roller 22 as a transfer fixing body and a pressure roller 34 as a pressure body are provided facing each other, and the outer peripheral surfaces of the rollers are approached by an urging means such as a spring 23 ( In the present embodiment, the pressure roller 34 is urged toward the transfer and fixing roller 22), and a nip portion N is formed at the contact portion. As shown, the transfer and fixing roller 22 is formed as a roller-shaped member.

  A toner image (hereinafter, also simply referred to as “toner”) primarily transferred from each of the photoreceptors 3Y, 3M, 3C, and 3B onto the intermediate transfer belt 2 is applied to the driving roller 9 by a secondary bias applying unit (not shown). The image is secondarily transferred to the transfer fixing roller 22 by electrostatic force by bias (including superposition of AC, pulse, etc.). Therefore, on the surface layer of the intermediate transfer belt 2, PFA (copolymer of tetrafluoroethylene and perfluoroalkoxyethylene) or PTFE (polytetrafluoroethylene) which is a fluorine-based resin material is used so that the toner is easily transferred. A release layer such as is coated.

As shown in FIG. 1, in the present embodiment, the intermediate transfer belt 2 is viewed from the secondary transfer nip portion that is a contact portion with the transfer fixing roller 22 with respect to the rotation direction indicated by the arrow in FIG. It has an intermediate transfer member heat reflux device 35 (hereinafter referred to as “heat reflux device 35”) as heat transfer means for the intermediate transfer member that transfers heat from the downstream portion B to the upstream portion A of the intermediate transfer belt 2. It is said.
The heat reflux device 35 is characterized in that the back surfaces of the upstream portion A and the downstream portion B of the intermediate transfer belt 2 are connected by contact with a member having high thermal conductivity.

On the back surface of the intermediate transfer belt 2 located in the vicinity of the driving roller 9, the thermal conductivity of the upstream transfer portion A and the downstream portion B of the secondary transfer nip portion is respectively measured in two directions with respect to the rotation direction of the intermediate transfer belt 2. The metal plate 26 which is a high member is in contact. The metal plate 26 is made of copper, aluminum, or an alloy using these metals, and has a width of the intermediate transfer belt 2 (refers to a width dimension in a direction perpendicular to the moving / rotating direction of the intermediate transfer belt 2). They are formed with approximately the same width.
Although the metal plate is used in the present embodiment, a non-metallic material having a high thermal conductivity such as a graphite sheet may be used. These metal plates 26 can be connected by one or a plurality of heat pipes 27 to promote the movement of heat from the downstream portion B to the upstream portion A.
Instead of the heat pipe 27, a high thermal conductivity material such as a graphite sheet may be used.

Between the intermediate transfer belt 2 and the transfer fixing roller 22, a heat insulating plate 19 is provided as a heat shielding member or a heat movement inhibiting member for suppressing heat radiation (heat movement) from the transfer fixing roller 22 to the intermediate transfer belt 2. It has been. The heat insulating plate 19 is formed in a shape having an opening so as to suppress heat radiation to the intermediate transfer belt 2 as much as possible without obstructing the secondary transfer from the intermediate transfer belt 2 to the transfer fixing roller 22. The fixing device main body and the image forming apparatus main body may be provided on either side. As the heat transfer inhibiting member, a plate-like member having a metallic luster with low emissivity is preferable, and an excellent effect can be obtained particularly when two metal sheets are arranged with a minute gap or a heat insulating material interposed therebetween. Moreover, when the thin plate which contains the micro heat pipe structure used for cooling CPU of a notebook personal computer is used, a heat transfer suppression member can be kept at low temperature and heat transfer can be suppressed. Further, a cooling roller 13 as a cooling member for removing the heat of the intermediate transfer belt 2 may be provided between the secondary transfer nip portion and the transfer portion for the most upstream photoconductor 3B as necessary. The cooling roller 13 is made of a material having high thermal conductivity, and rotates in contact with the intermediate transfer belt 2. In the present embodiment, both the heat insulating plate 19 and the cooling roller 13 are provided. However, either one may be provided.
According to the present embodiment, by including the heat reflux device 35, the temperature of the intermediate transfer belt 2 (intermediate transfer member) can be reduced, and thermal deterioration on the intermediate transfer belt 2 side can be suppressed. Further, the degree of freedom in designing the transfer fixing roller 22 (transfer fixing member) can be increased.

The transfer and fixing roller 22 includes a metal pipe-shaped cored bar 22a made of aluminum or the like, an elastic layer 22b made of silicone rubber or the like covering the outer periphery of the cored bar 22a, and PFA or PTFE which are fluorine-based resin materials. And a release layer 22c coated so as to cover the elastic layer 22b.
The thickness of the cored bar 22a is desirably 1 mm or less for speeding up the warm-up. The elastic layer 22b desirably has a lower limit of 0.05 mm or more in order to form a nip sufficient to transfer and fix the toner onto the paper P. The upper limit is desirably 0.5 mm or less. The thickness of the release layer 22 c is preferably in the range of 5 to 30 μm so that the transfer and fixing roller 22 can follow the minute irregularities of the paper P.
The pressure roller 34 has substantially the same configuration as the transfer fixing roller 22.
The transfer fixing roller 22 and the pressure roller 34 are rotationally driven in the direction of the arrow in FIG. 1 by a drive mechanism (not shown).

In the present embodiment, as a heating means for heating the toner image on the surface layer of the intermediate transfer belt 2 in the vicinity of the transfer fixing roller 22 and immediately before the nip portion N, the radiant heat of the halogen heater 21 and the halogen heater 21 is used. A reflecting plate 31 is provided for efficiently applying the toner image. Further, a thermistor (not shown) provided in a non-image area for measuring the surface temperature of the transfer fixing roller 22 and the halogen heater 21 on based on the surface temperature of the transfer fixing roller 22 measured by the thermistor. A temperature controller (not shown) for controlling / off is provided, and the temperature can be controlled independently.
The heating means in FIG. 1 shows radiant heat from the outside by the halogen heater 21, but is not limited to this, and the halogen heater 21 may be used inside the transfer fixing roller 22 as shown in FIG. 2. The configuration shown in FIG. 2 is different from the configuration shown in FIG. 1 only in that a halogen heater 21 is disposed inside the transfer fixing roller 22, and the other configuration is the same as the configuration shown in FIG. is there.
In addition, as shown in FIG. 3, an exciting coil 25 may be provided in the vicinity of the transfer fixing roller 22 and immediately before the nip portion N, and the heating means may be induction heating. At that time, the transfer fixing roller 22 is made of a metal pipe-like metal core 22a such as aluminum similar to that shown in FIG. 1, and nickel, stainless steel, aluminum or aluminum and stainless steel as a heat generating layer covering the outer periphery of the metal core 22a. A metal conductive layer (not shown) of a composite material with steel, an elastic layer 22b similar to that shown in FIG. 1 covering the metal conductive layer, and a release layer 22c similar to that shown in FIG. . The configuration shown in FIG. 3 is different from the configuration shown in FIG. 1 only in the points described above, and the other configurations are the same as those shown in FIG.

  Further, the release layer 22c of the transfer fixing roller 22 is formed of a conductive fluorine-based resin material in which a conductive substance such as carbon is dispersed, and is connected to the cored bar 22a, thereby transferring the transfer bias between the release layers 22c. Can be applied, the transfer bias can be lowered, and toner scattering (transfer dust) during transfer can be suppressed.

  Next, a characteristic operation of the present embodiment will be described based on FIG. Since the unfixed toner image formed on the intermediate transfer belt 2 is negatively charged, the drive roller 9 side is set to −0.5 kV to −2 kV, and the cored bar 22a of the transfer fixing roller 22 is set to 0V. By applying a bias, the image is sequentially transferred to the transfer fixing roller 22. At this time, toner (not shown) on the transfer fixing roller 22 is heated to a predetermined temperature by the halogen heater 21. The bias may be applied so that the driving roller 9 side is 0 V and the cored bar 22a of the transfer fixing roller 22 is +0.5 kV to +2 kV. In this embodiment, the toner is negatively charged. However, bias applying means (not shown) is applied to the driving roller 9 and the transfer fixing roller 22 so that the positively charged toner is electrostatically transferred. ) Or ground.

  The heat transferred from the transfer fixing roller 22 heated by the heating means to the intermediate transfer belt 2 is transferred from the metal plate 26 in contact with the back surface of the downstream portion B of the intermediate transfer belt 2 through the heat pipe 27 to the upstream portion. Heat is transferred to the intermediate transfer belt 2 in contact therewith via the metal plate 26 of A. By this operation, the temperature after the downstream portion B of the intermediate transfer belt 2 is lowered and further lowered by the cooling roller 13 to prevent the toner from adhering to the intermediate transfer belt 2, and each of the photoreceptors 3Y, 3M, The temperature rise of 3C and 3B can be mitigated.

  After the transferred toner image is completely held on the transfer and fixing roller 22, the surface image is formed. A fixed image is formed on the paper P conveyed from the paper supply unit 15, and is peeled off from the transfer / fixing rotator and then discharged. That is, the unfixed toner image formed on the transfer fixing roller 22 is thermally fused on the sheet P conveyed from the sheet feeding unit 15 to the nip N through the sheet feeding roller 16, the conveyance roller pair 17, and the registration roller pair 18. At the same time, it is pressed and fixed by the pressure roller 34. The paper P on which the fixing toner image is formed is peeled off from the transfer fixing roller 22 and discharged.

According to the present embodiment, as the heat reflux device 35, a metal such as copper or aluminum, a graphite sheet, or the like is provided on each back surface of the upstream portion A and the downstream portion B of the intermediate transfer belt 2 as viewed from the secondary transfer nip portion. The metal plate 26 which is a plate-like body having a high thermal conductivity is installed, and the metal plates 26 are connected to each other by a metal such as copper or aluminum, a graphite sheet, or a heat pipe. The heat reflux effect can be increased by increasing the contact area between the intermediate member) and the intermediate transfer belt 2 (intermediate transfer member).
In addition, since the transfer fixing member is formed as a transfer fixing roller 22 which is a roller-like member, the image forming apparatus can be downsized.

(Second Embodiment)
FIG. 4 shows a second embodiment. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and unless otherwise specified, the description of the configuration and functions already described is omitted, and only the main parts are described. (The same applies to other embodiments below).
The toner heating means (not shown) of the second embodiment may be any method described in the first embodiment.
Compared with the first embodiment shown in FIGS. 1 to 3, the second embodiment replaces the heat reflux device 35 with the heat transfer device for the intermediate transfer member 36 as the heat reflux means for the intermediate transfer member. The difference is only in using (hereinafter referred to as “heat reflux device 36”). The configuration other than this difference is the same as that of the first embodiment.
The heat reflux device 36 is a heat transfer roller 28a as an odd number of roller-like rotating bodies with high thermal conductivity capable of rotating the respective back surfaces of the upstream portion A and the downstream portion B of the intermediate transfer belt 2 in contact with each other. It is characterized in that it is configured to be in contact with each other at 28b and 28c.

As shown in FIG. 4, the heat transfer roller 28a is in contact with the inner side of the region surrounded by the intermediate transfer belt 2 and the rear surface thereof at the upstream portion A, and the heat transfer roller 28b at the downstream portion B. In addition, since another heat transfer roller 28c is in contact therewith, heat transfer from the downstream portion B to the upstream portion A can be promoted. These heat transfer rollers 28a, 28b, and 28c are made of copper, aluminum, or an alloy using these metals, and are formed to have a width substantially the same as the width of the intermediate transfer belt 2, and have a heat capacity. To make it smaller, the roller is hollow.
End plates (both not shown) to which shafts are fixed are attached and fixed to both ends of the heat transfer rollers 28a, 28b, 28c on the front side and the back side of the paper surface, and the heat transfer rollers 28a, 28b, Reference numeral 28c denotes a support structure in which the shaft is rotatably supported by the apparatus main body, and is rotatably supported via the shaft. Further, the heat transfer roller 28a and the heat transfer roller 28b are in contact with the intermediate transfer belt 2, and the heat transfer roller 28c is in contact with the heat transfer rollers 28a and 28b so that they can be driven to rotate.
In order to ensure that each heat transfer roller 28a, 28b, 28c can be driven and rotated reliably, a structure that meshes with the end of each heat transfer roller 28a, 28b, 28c removed from the contact portion with the intermediate transfer belt 2 is added. Alternatively, the surfaces may be appropriately roughened so that the contact surfaces rotate due to friction. Furthermore, a heat pipe (not shown) may be inserted into the heat transfer rollers 28a, 28b, and 28c in order to reduce the temperature rise at the end of the intermediate transfer belt 2 that occurs during continuous paper feeding. In this embodiment, the number of heat transfer rollers is three. However, any number of heat transfer rollers may be used as long as the number of heat transfer rollers is an odd number according to the layout of the intermediate transfer belt 2.
FIG. 5 shows a color copying machine 100 (image forming apparatus) when the number of heat transfer rollers 28 is one. The rotation support structure of the heat transfer roller 28 at this time is substantially the same as that described above.

The operation is almost the same as in the first embodiment. The heat transferred from the heated transfer fixing roller 22 to the intermediate transfer belt 2 is transferred from the heat transfer roller 28b at the downstream portion B to the heat transfer roller 28c and through the heat transfer roller 28a at the upstream portion A. Heat is transferred to. By this operation, the temperature after the downstream portion B of the intermediate transfer belt 2 is lowered and further lowered by the cooling roller 13 to prevent the toner from adhering to the intermediate transfer belt 2, and each of the photoreceptors 3Y, 3M, The temperature rise of 3C and 3B can be mitigated.
Compared to the first embodiment, the contact area of the intermediate transfer belt 2 with the heat transfer rollers 28a and 28b is small, so the heat reflux effect is small, but the sliding life is small, so the life of the intermediate transfer belt 2 is long. The noise can be reduced.

(Third embodiment)
FIG. 6 shows a third embodiment. The toner heating means (not shown) of the third embodiment may be any method described in the first embodiment.
Compared with the first embodiment shown in FIGS. 1 to 3, the third embodiment replaces the heat reflux device 35 and heat transfer device 37 for the intermediate transfer member as a heat reflux means for the intermediate transfer member. The difference is only in using (hereinafter referred to as “heat reflux device 37”). The configuration other than this difference is the same as that of the first embodiment.
The heat reflux device 37 stretches the back surfaces of the upstream portion A and the downstream portion B of the intermediate transfer belt 2 between these rollers 30 via two heat transfer belt support rollers 30 as rotation supports. The heat transfer belt 29 as a belt-like rotating body having a high thermal conductivity is connected in contact with each other.

  As shown in FIG. 6, a heat transfer belt support roller that is rotatably provided in the upstream portion A and the downstream portion B, respectively, inside the area surrounded by the intermediate transfer belt 2 and on the back surface thereof. Since the heat transfer belt 29 stretched by 30 is in contact, heat transfer from the downstream portion B to the upstream portion A can be promoted. One of the heat transfer belt support rollers 30 is a drive roller that is rotationally driven by a drive mechanism (not shown), and the remaining rollers are driven rollers. The heat transfer belt support roller 30 is formed of a metal having high thermal conductivity or an elastic body such as a sponge roller that can increase the contact area with the intermediate transfer belt 2. The heat transfer belt 29 is composed of a metal belt having a high thermal conductivity or a heat-resistant base material such as polyimide and a non-metallic material having a high thermal conductivity such as a graphite sheet.

  Compared to the second embodiment, the third embodiment has a larger layout restriction, but a material having high thermal conductivity is used for the heat transfer belt 29 (belt-shaped rotating body) that performs heat reflux, and the heat transfer is performed. By making the heat belt support roller 30 (rotary support) an elastic body such as a sponge having a low thermal conductivity, the contact area between the intermediate transfer belt 2 (intermediate transfer body) and the heat reflux device 37 is increased, thereby causing heat reflux. The effect can be increased. In addition, since the sliding is small as in the second embodiment, the life of the intermediate transfer belt 2 can be increased, and noise can be suppressed.

(Fourth embodiment)
FIG. 7 shows a fourth embodiment. The toner heating means (not shown) of the fourth embodiment may be any method described in the first embodiment.
In the fourth embodiment, as compared with the third embodiment, instead of the thermal reflux device 37, an intermediate transfer member thermal reflux device 37A (hereinafter referred to as "thermal reflux device 37A") as an intermediate transfer member thermal reflux means. The only difference is that “ The configuration other than this difference is the same as that of the third embodiment.
Compared with the heat reflux device 37, the heat reflux device 37 </ b> A is stretched between the two heat transfer belt support rollers 30 on the back surfaces of the upstream portion A and the downstream portion B of the intermediate transfer belt 2. The only difference is that the heat transfer belt 29 is in contact and connected. As shown in the figure, inside the region surrounded by the intermediate transfer belt 2, the heat transfer is stretched by a heat transfer belt support roller 30 that is rotatably provided at each of the upstream part A and the downstream part B by two. Since the heat belt 29 is in contact with the back surface of the intermediate transfer belt 2, it is possible to promote the movement of heat from the downstream portion B to the upstream portion A. The materials and specifications of the heat transfer belt support roller 30 and the heat transfer belt 29 are the same as in the third embodiment.

  Compared with the third embodiment, the fourth embodiment has a larger layout restriction, but the heat transfer belt 29 and the intermediate transfer belt 2 have a larger contact area, so that heat is efficiently transferred. There is an advantage that you can.

(Fifth embodiment)
FIG. 8 shows a fifth embodiment. Compared with the first embodiment, the fifth embodiment replaces the transfer fixing roller 22 with a transfer fixing belt 24 as a transfer fixing body, and the moving direction of the transfer fixing belt 24 is the same. The heat-refluxing means for the transfer-fixing member moves heat from the downstream portion D to the upstream portion C of the transfer-fixing belt 24 as viewed from the nip portion N that is the contact portion with the pressure roller 34 in the rotation direction indicated by the arrow in the figure. The main difference is that a heat reflux device 35 'for the transfer fixing member (hereinafter referred to as "heat reflux device 35'") is provided.

According to the present embodiment, the transfer fixing member 24 is a transfer fixing belt 24 that is a belt-like member, so that the temperature at the secondary transfer nip portion is lowered as compared with the case where the transfer fixing roller 22 is a roller-like member. Accordingly, the temperature of the intermediate transfer belt 2 can be lowered and lowered accordingly.
The transfer and fixing belt 24 is stretched by a transfer and fixing belt driving roller 32, a transfer and fixing belt driven roller 33, and the transfer and fixing roller 22, and is provided to face the transfer and fixing roller 22 through the transfer and fixing belt 24. The pressure roller 34 is urged and pressed toward the transfer and fixing roller 22 by a pressing means such as a spring 23 to form a nip portion N. The transfer fixing belt driving roller 32 is rotationally driven in the arrow direction in FIG. 8 by a driving mechanism (not shown) together with the transfer fixing roller 22. As a result, the transfer and fixing belt 24 is moved and rotated in the direction of the arrow in FIG.
The transfer fixing belt 24 has the same material configuration as that of the intermediate transfer belt 2. That is, the transfer fixing belt 24 was coated on the surface of a heat-resistant base material such as polyimide, an elastic layer of about 0.05 to 0.5 mm formed on the surface layer portion of the base material, and the surface of the elastic layer. It is comprised with mold release layers, such as PFA and PTFE which are 5-30 micrometers fluororesin-type material.

  The toner heating means (not shown) of the fifth embodiment may be any method described in the first embodiment. When induction heating is used as the heating means, that is, with reference to FIG. 3, an induction coil 25 is provided in the vicinity of the transfer fixing roller 22 with the transfer fixing belt 24 interposed therebetween and immediately before the nip portion N, and induction is performed. In the case of heating, the transfer and fixing belt 24 is made of a heat-resistant base material such as polyimide and nickel, stainless steel, aluminum, or a composite material of aluminum and stainless steel as a heat generating layer formed on the base material. A metal conductive layer, an elastic layer of about 0.05 to 0.5 mm formed on the surface layer portion of the metal conductive layer, and PFA which is a fluororesin material of 5 to 30 μm coated on the surface of the elastic layer And a release layer such as PTFE.

The heat reflux device 35 ′ is characterized in that the back surfaces of the upstream portion C and the downstream portion D of the transfer and fixing belt 24 are in contact with each other with a member having high thermal conductivity. As shown in FIG. 8, an inner region surrounded by the transfer and fixing belt 24, and on the back surface thereof, an upstream portion C of the nip portion N with respect to the rotation direction indicated by the arrow of the transfer and fixing belt 24. And the downstream portion D are disposed so that the metal plate 26 which is a member having high thermal conductivity is in contact with each other. The metal plate 26 is made of copper, aluminum, or an alloy using these metals, and has a width of the transfer fixing belt 24 (refers to a width dimension in a direction orthogonal to the moving / rotating direction of the transfer fixing belt 24). They are formed with approximately the same width. As described above, the heat reflux device 35 ′ has substantially the same configuration as the heat reflux device 35 of the first embodiment.
Although the metal plate is used in the present embodiment, a non-metallic material having a high thermal conductivity such as a graphite sheet may be used. These metal plates 26 can be connected by one or a plurality of heat pipes 27 to promote the movement of heat from the downstream portion D to the upstream portion C. Further, instead of the heat pipe 27, a high thermal conductivity material such as a graphite sheet may be used.

  Next, a characteristic operation of the present embodiment will be described based on FIG. Since the unfixed toner image formed on the intermediate transfer belt 2 is negatively charged, the drive roller 9 side is set to −0.5 kV to −2 kV, and the core of the transfer fixing belt driven roller 33 is set to 0V. By being applied with a bias, the image is sequentially transferred to the transfer fixing belt 24. At this time, the toner image is heated to a predetermined temperature by any one of the heating means shown in FIGS. Further, the bias may be applied so that the driving roller 9 side is 0 V, and the core metal of the transfer fixing belt driven roller 33 is +0.5 kV to +2 kV. In this embodiment, the toner is negatively charged. However, bias applying means (see FIG. 5) is applied to the driving roller 9 and the transfer fixing belt driven roller 33 so that the positively charged toner is electrostatically transferred. (Not shown) or a ground may be provided.

The heat after passing through the nip portion N of the transfer fixing belt 24 is transferred from the metal plate 26 in the downstream portion D through the heat pipe 27 to the transfer fixing belt 24 after the secondary transfer nip portion via the metal plate 26 in the upstream portion C. Heat is transferred to. By this operation, the temperature after the downstream portion D of the transfer fixing belt 24 is lowered, and heat applied to the intermediate transfer belt 2 in the secondary transfer nip portion can be reduced. Further, by applying heat to the transfer and fixing belt 24 after the secondary transfer nip portion, the toner image can be used as heat for preheating.
On the other hand, the heat transferred to the intermediate transfer belt 2 in the secondary transfer nip portion is the temperature after the downstream portion B of the intermediate transfer belt 2 due to the operation and function of the heat reflux device 35 as described in the first embodiment. Lower than that of the first embodiment and further lowered by the cooling roller 13, the toner is prevented from adhering to the intermediate transfer belt 2, and the temperature rise of each of the photoreceptors 3Y, 3M, 3C, 3B is mitigated. be able to.

  After the toner image transferred from the intermediate transfer belt 2 is completely held on the transfer and fixing belt 24, a surface image is formed. The unfixed toner image formed on the transfer and fixing belt 24 is heat-sealed to the sheet P conveyed from the sheet feeding unit 15 to the nip N through the sheet feeding roller 16, the conveyance roller pair 17, and the registration roller pair 18. At the same time, the pressure roller 34 is pressed and fixed. The paper P on which the fixing toner image is formed is peeled off from the transfer fixing belt 24 and discharged.

  According to the present embodiment, as the heat reflux device 35 ′, the back surface of the upstream portion C and the downstream portion D of the transfer fixing belt 24 as viewed from the nip portion N, the heat of a metal such as copper or aluminum, or a graphite sheet or the like. A metal plate 26 having a high conductivity is installed, and the metal plates 26 are connected to each other by a metal such as copper or aluminum, a graphite sheet, or a heat pipe. ) And the transfer fixing belt 24 (transfer fixing body) can be increased to increase the heat reflux effect.

  Although the embodiment in which the heat transfer device 35 is provided in the intermediate transfer belt 2 and the heat return device 35 ′ is provided in the transfer fixing belt 24 as described above is shown, any intermediate in the first to fourth embodiments described above is shown. The heat reflux devices 35, 36, 37, 37A and the like of the transfer belt 2 may be used by being transferred to the transfer fixing belt 24, and may be freely combined with the intermediate transfer belt 2 including any heat reflux device. Hereinafter, a modified example by an appropriate combination and a characteristic operation thereof will be briefly described.

FIG. 9 shows a modification of the first embodiment. In the modification shown in FIG. 9, the transfer and fixing roller 22 of the first embodiment shown in any one of FIGS. 1 to 3 is replaced with a transfer and fixing belt 24, and the second embodiment shown in FIG. Instead of the heat reflux device 36 of the embodiment, a transfer fixing member heat reflux device 36 ′ (hereinafter referred to as “heat reflux device 36 ′”) as a transfer fixing member heat reflux means having the same configuration as this is transferred. In this configuration, the fixing belt 24 is disposed and replaced.
The heat reflux device 36 ′ is a heat transfer roller 28 a as an odd number of roller-like rotating bodies with high thermal conductivity that can rotate by contacting the back surfaces of the upstream portion C and the downstream portion D of the transfer fixing belt 24 with each other. , 28b and 28c are connected to each other.

The heat after passing through the nip portion N of the transfer fixing belt 24 is transferred from the heat transfer roller 28b in the downstream portion D to the heat transfer roller 28c, and transferred after the secondary transfer nip portion through the heat transfer roller 28a in the upstream portion C. Heat is transferred to the fixing belt 24. By this operation, the temperature after the downstream portion D of the transfer fixing belt 24 is lowered, and heat applied to the intermediate transfer belt 2 in the secondary transfer nip portion can be reduced. Further, by applying heat to the transfer and fixing belt 24 after the secondary transfer nip portion, the toner image can be used as heat for preheating.
On the other hand, the heat transferred to the intermediate transfer belt 2 in the secondary transfer nip portion is the temperature after the downstream portion B of the intermediate transfer belt 2 due to the operation and function of the heat reflux device 35 as described in the first embodiment. Lower than that of the first embodiment and further lowered by the cooling roller 13, the toner is prevented from adhering to the intermediate transfer belt 2, and the temperature rise of each of the photoreceptors 3Y, 3M, 3C, 3B is mitigated. be able to.
The modification shown in FIG. 9 has a smaller heat contact effect than the sixth embodiment because the contact area between the transfer and fixing belt 24 and the heat transfer rollers 28a and 28b is small, but the sliding is small. Therefore, the life of the transfer and fixing belt 24 can be extended, and noise can be suppressed.

FIG. 10 shows a modification of the first embodiment. In the modified example shown in FIG. 10, the transfer fixing roller 22 of the first embodiment shown in any one of FIGS. 1 to 3 is replaced with a transfer fixing belt 24, and the third embodiment shown in FIG. In place of the heat reflux device 37 of the embodiment, a transfer fixing member heat reflux device 37 ′ (hereinafter referred to as “heat reflux device 37 ′”) as a transfer fixing member heat reflux means having the same configuration as this is transferred. In this configuration, the fixing belt 24 is disposed and replaced.
The heat reflux device 37 ′ is a belt-like rotator having a high thermal conductivity in which the back surfaces of the upstream portion C and the downstream portion D of the transfer fixing belt 24 are stretched between two heat transfer belt support rollers 30. The heat transfer belt 29 is contacted and connected.

The heat after passing through the nip portion N of the transfer fixing belt 24 is transferred to the heat transfer belt 29 in contact with the transfer fixing belt 24 in the upstream portion C by the heat transfer belt 29 in contact with the transfer fixing belt 24 in the downstream portion D. heat. By this operation, the temperature after the downstream portion D of the transfer fixing belt 24 is lowered, and heat applied to the intermediate transfer belt 2 in the secondary transfer nip portion can be reduced. Further, by applying heat to the transfer and fixing belt 24 after the secondary transfer nip portion, the toner image can be used as heat for preheating.
On the other hand, the heat transferred to the intermediate transfer belt 2 in the secondary transfer nip portion is the temperature after the downstream portion B of the intermediate transfer belt 2 due to the operation and function of the heat reflux device 35 as described in the first embodiment. Lower than that of the first embodiment and further lowered by the cooling roller 13, the toner is prevented from adhering to the intermediate transfer belt 2, and the temperature rise of each of the photoreceptors 3Y, 3M, 3C, 3B is mitigated. be able to.

The modification shown in FIG. 10 has a larger layout restriction than the modification shown in FIG. 9, but the heat transfer belt support roller 30 is made of an elastic body such as a sponge having a low thermal conductivity, so that the transfer and fixing belt is used. By increasing the contact area with 24, the heat reflux effect can be increased. Further, since the sliding is small as in the modification shown in FIG. 9, the life of the transfer and fixing belt 24 can be increased, and noise can be suppressed.
In the modification shown in FIG. 10, a heat pipe (not shown) may be inserted inside the heat transfer belt support roller 30 in order to reduce the end temperature rise of the transfer and fixing belt 24 that occurs during continuous paper feeding.

  FIG. 11 shows a modification of the second embodiment. In the modification shown in FIG. 11, the transfer and fixing roller 22 of the second embodiment shown in FIG. 4 is replaced with the transfer and fixing belt 24 of the fifth embodiment shown in FIG. It is the example which attached the heat | fever reflux apparatus 35 'similar to 5th Embodiment.

  FIG. 12 shows a modification of the second embodiment. In the modification shown in FIG. 12, the transfer fixing roller 22 of the second embodiment shown in FIG. 5 is replaced with the transfer fixing belt 24 of the fifth embodiment shown in FIG. It is the example which attached the heat | fever reflux apparatus 35 'similar to 5th Embodiment.

  FIG. 13 shows a modification of the third embodiment. In the modification shown in FIG. 13, the transfer fixing roller 22 of the third embodiment shown in FIG. 6 is replaced with the transfer fixing belt 24 of the fifth embodiment shown in FIG. It is the example which attached the heat | fever reflux apparatus 35 'similar to 5th Embodiment.

  FIG. 14 shows a modification of the fourth embodiment. In the modification shown in FIG. 14, the transfer fixing roller 22 of the fourth embodiment shown in FIG. 7 is replaced with the transfer fixing belt 24 of the fifth embodiment shown in FIG. It is the example which attached the heat | fever reflux apparatus 35 'similar to 5th Embodiment.

FIG. 15 shows a modification in which the layout of the first embodiment is changed. A modified example of this layout change is a form in which the transfer fixing device 20 of the first embodiment shown in any one of FIGS. 1 to 3 is disposed on the intermediate transfer belt 2.
Considering the convection of the air in the apparatus main body, the transfer fixing roller 22 is arranged at the upper portion, so that the air warmed by the heating means does not easily apply heat to the intermediate transfer belt 2, so that energy saving is further improved.

(Sixth embodiment)
FIG. 16 shows a sixth embodiment. The toner heating means (not shown) of the sixth embodiment may be any method described in the first embodiment. In the sixth embodiment, a bias applying means 40 for applying a bias having a polarity opposite to that of the toner is provided on the metal plate 26 in contact with the upstream portion A side of the intermediate transfer belt 2 of the first embodiment. In the figure, the metal plate 26 on the upstream portion A side is disposed immediately before the secondary transfer nip portion so as not to touch the driving roller 9 of the intermediate transfer belt 2.

  The operation of the sixth embodiment will be described with reference to FIG. As described in the first embodiment, it is assumed that the toner is negatively charged. The drive roller 9 of the intermediate transfer belt 2 is connected to the ground so as to be 0V, and a bias is applied so that the cored bar 22a of the transfer fixing roller 22 is +0.5 to +2 kV. The toner electrostatically transferred from the photoreceptors 3Y, 3M, 3C, and 3B to the intermediate transfer belt 2 is negatively charged, and the toner is secondary by the upstream side A-side metal plate 26 to which a positive bias is applied. The toner is attracted to the intermediate transfer belt 2 just before the transfer nip portion, and transferred to the transfer fixing roller 22 at the secondary transfer nip portion. By this operation and action, transfer dust at the secondary transfer nip portion can be reduced.

  FIG. 17 shows a form in which the metal plate 26 on the upstream portion A side in FIG. In any case, as compared with the case where the metal plate 26 on the upstream portion A side is in a float state or when −0.5 to −2 kV is applied, toner scattering (transfer dust) is reduced when one dot is enlarged. confirmed. In FIG. 16 and FIG. 17 and the like, the heat insulating plate 19 is not shown in order to avoid complication of the drawing.

  As described above, the present invention has been described with respect to specific embodiments and modifications. However, the technical scope disclosed by the present invention is limited to those exemplified in the above-described embodiments and modifications. However, those skilled in the art can configure various embodiments, modifications, and examples in accordance with the necessity and application within the scope of the present invention. Is obvious.

1 is a schematic front view of an image forming apparatus showing a first embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a modification of the first embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a modification of the first embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a second embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a modification of the second embodiment of the present invention. It is a schematic front view of the image forming apparatus which shows the 3rd Embodiment of this invention. It is a schematic front view of the image forming apparatus which shows the 4th Embodiment of this invention. It is a schematic front view of the image forming apparatus which shows the 5th Embodiment of this invention. It is a schematic front view of an image forming apparatus showing a modification of the first embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a modification of the first embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a modification of the second embodiment of the present invention. It is a schematic front view of an image forming apparatus showing a modification of the second embodiment of the present invention. It is a schematic front view of the image forming apparatus which shows the modification of the 3rd Embodiment of this invention. It is a schematic front view of the image forming apparatus which shows the modification of the 4th Embodiment of this invention. It is a schematic front view of an image forming apparatus showing a layout modification of the first embodiment of the present invention. It is a schematic front view of the image forming apparatus which shows the 6th Embodiment of this invention. It is a schematic front view of the image forming apparatus which shows the modification of the 6th Embodiment of this invention.

Explanation of symbols

1 Image forming unit 2 Intermediate transfer belt (intermediate transfer member)
3Y, 3M, 3C, 3B photoconductor (image carrier)
4Y, 4M, 4C, 4B Charging devices 5Y, 5M, 5C, 5B Writing devices 6Y, 6M, 6C, 6B Developing devices 7Y, 7M, 7C, 7B Primary transfer device 9 Driving roller 10 Driving roller 11 Driven roller 13 Cooling roller 15 Paper feed unit 19 Heat insulation plate 20 Transfer fixing device 21 Halogen heater (heating means)
22 Transfer fixing roller (transfer fixing member, roller-shaped member)
22c Release layer 24 Transfer fixing belt (transfer fixing member, belt-shaped member)
25 Excitation coil (heating means)
26 Metal plate (component of heat reflux means for intermediate transfer member, heat reflux means for transfer fixing member)
27 Heat pipe (component of heat reflux means for intermediate transfer member, heat reflux means for transfer fixing member)
28, 28a, 28b, 28c Heat transfer roller (components of heat reflux means for intermediate transfer member, heat reflux means for transfer fixing member, roller-like rotating member)
29 Heat transfer belt (components of intermediate reflux member heat reflux means and transfer fixing member heat reflux means)
32 Transfer fixing belt driving roller 33 Transfer fixing belt driven roller 34 Pressure roller (pressure member)
35, 36, 36A, 37 Intermediate transfer member heat reflux device (intermediate transfer member heat reflux means)
35 ', 36', 37 'heat reflux device for transfer fixing body (heat reflux means for transfer fixing body)
40 Bias applying means A, C upstream part B, D downstream part P paper (an example of a recording medium)

Claims (12)

An unfixed image is formed on the image carrier, the unfixed image is subsequently transferred to an intermediate transfer member, and then the unfixed image transferred to the intermediate transfer member is transferred to the transfer fixing member, and then the transfer is further performed. In an image forming apparatus for simultaneously transferring and fixing to a recording medium by pressing the transfer fixing body and a pressure body while heating an unfixed image on a fixing body,
And a heat reflux means for the intermediate transfer member that moves heat from the downstream portion to the upstream portion of the intermediate transfer member as viewed from the contact portion with the transfer fixing member with respect to the moving direction of the intermediate transfer member. Image forming apparatus. The image forming apparatus according to claim 1.
The intermediate transfer member heat reflux means has a configuration in which the back surfaces of the upstream portion and the downstream portion of the intermediate transfer member are in contact with each other by a member having high thermal conductivity. apparatus. The image forming apparatus according to claim 1.
The heat transfer means for the intermediate transfer member causes the back surfaces of the upstream portion and the downstream portion of the intermediate transfer member to contact each other with an odd number of roller-like rotating members having high thermal conductivity that can rotate in contact with each other. An image forming apparatus having a connected configuration. The image forming apparatus according to claim 1.
The heat transfer means for the intermediate transfer member has a configuration in which the back surfaces of the upstream portion and the downstream portion of the intermediate transfer member are contacted and connected by a belt-like rotating member having high thermal conductivity. Image forming apparatus. The image forming apparatus according to any one of claims 1 to 4,
The image forming apparatus, wherein the transfer fixing member is a roller-shaped member. The image forming apparatus according to any one of claims 1 to 4,
The image forming apparatus, wherein the transfer fixing member is a belt-like member. The image forming apparatus according to claim 6.
A heat-refluxing unit for the transfer-fixing member that moves heat from the downstream portion to the upstream portion of the transfer-fixing member as viewed from the contact portion with the pressure member in the moving direction of the transfer-fixing member. Image forming apparatus. The image forming apparatus according to claim 7.
The image forming apparatus is characterized in that the heat fixing means for the transfer fixing body has a structure in which a member having a high thermal conductivity is connected to each back surface of the upstream portion and the downstream portion of the transfer fixing body. apparatus. The image forming apparatus according to claim 7.
The heat fixing means for the transfer fixing member is brought into contact with the back surfaces of the upstream portion and the downstream portion of the transfer fixing member by an odd number of roller-like rotating members having high thermal conductivity that can rotate in contact with each other. An image forming apparatus having a connected configuration. The image forming apparatus according to claim 7.
The heat-refluxing unit for the transfer-fixing member has a configuration in which the back surfaces of the upstream portion and the downstream portion of the transfer-fixing member are connected by being contacted by a belt-like rotating member having high thermal conductivity. Image forming apparatus.   A heat reflux means for an intermediate transfer member according to any one of claims 1 to 4 and a heat reflux means for a transfer fixing member according to any one of claims 7 to 10 are provided. An image forming apparatus. The image forming apparatus according to any one of claims 1 to 11,
The transfer fixing body is an image forming apparatus having at least a release layer and using a developer of four or more colors, and the heat transfer means for the intermediate transfer body is conductive and has a polarity opposite to that of the ground or the developer. An image forming apparatus, wherein a bias is applied.

Images