JP2001194946A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device which performs such an excellent fixing action that fixing irregularity is little when a toner image on a transfer material is fixed at a nip part by accelerating the temperature rise of a belt member whose heat conductivity is bad, shortening the warming-up time and eliminating the change and the nonuniformity of the temperature of the belt member at a continuous printing time, which is provided with high-speed responsiveness and which is constituted so that the jam processing of the transfer material is facilitated at the nip part and an offset and a fixing irregularity are prevented from occurring at a fixing time by preventing a local temperature rise and local temperature drop from occurring when the transfer material is passed. SOLUTION: This fixing device is constituted so that a fixing belt unit is provided with a heating means abutting on the belt member from the inside of the belt member and heating the belt member between a 1st fixing roller member and a roller member. Besides, it is constituted so that the fixing belt unit can be opened including the heating means with the roller member where the belt member is laid as a supporting point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt-type fixing device used in an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, a fixing device used in an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile or the like includes a heating rubber roller having an elastic layer and maintained at a predetermined temperature, and a heating rubber roller. A heat roller fixing method in which a transfer material on which an unfixed toner image is formed is heated while being nipped and conveyed by a pressurized rubber roller having an elastic layer while being pressed against the roller.

However, in this type of apparatus, the heat capacity of the heat-generating rubber roller is large, so that the warm-up time is long, the temperature inside the elastic layer is high, and the life of the heat-generating rubber roller is shortened.

Further, many color images have a large solid area, and many of the solid images are other than black, so that uneven gloss is noticeable. When a hard roller is used as the heating rubber roller and the pressure rubber roller, there is a problem that image quality is deteriorated because uneven gloss is generated in accordance with unevenness of the paper or toner layer.

In order to solve the above problems, a fixing method using a metal belt (belt member) provided with a rubber layer and a heating roller (heating roller member) for heating the belt member inside the belt member has been proposed. It is disclosed in Japanese Patent Application Laid-Open No. 9-138599.

[0006]

However, in the fixing device disclosed in Japanese Patent Application Laid-Open No. 9-138599, a good image quality is obtained by using a belt member (metal belt) having an elastic layer (rubber layer). However, the temperature rise of the belt member having poor thermal conductivity due to the elastic layer is slow, and it takes time for warming up. There is a problem that the belt member is deteriorated, and the temperature of the belt member changes or the temperature becomes uneven during the continuous printing, so that the fixing unevenness occurs. Further, when a heating roller member (heating roller) for heating the belt member is provided in the belt member, heat hardly moves from the heating roller member (heating roller) to the inside of the belt member, and heat from the heating to the belt member surface is reduced. There is a problem that conduction takes time and high-speed printing is difficult. In particular, in the above fixing device, it is difficult to remove the jam at the nip portion of the transfer material, and the temperature of the transfer material locally increases and decreases due to the passing of the transfer material. The problem arises.

The present invention solves the above problems, speeds up the temperature rise of a belt member having poor thermal conductivity, shortens the warm-up time, and eliminates temperature changes and uneven temperature of the belt member during continuous printing. Then, at the time of fixing the toner image on the transfer material at the nip portion, it performs good fixing with little fixing unevenness, has high-speed response, and facilitates jam processing at the nip portion of the transfer material, Also, by preventing a local temperature rise and temperature drop due to the passing of the transfer material,
An object of the present invention is to provide a fixing device that prevents occurrence of offset and fixing unevenness.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a first fixing roller member which stretches a belt member on one side, and a roller member which stretches the other side of the belt member together with the first fixing roller member. Forming a fixing belt unit, and sandwiching the belt member, forming a pair with the first fixing roller member, and providing a second fixing roller member forming a nip portion;
In a fixing device for fixing a toner image on a transfer material in the nip portion, the belt member is contacted between the first fixing roller member and the roller member from the inside of the belt member to heat the belt member. A fixing unit provided in the fixing belt unit, and the fixing belt unit including the heating unit can be opened with the roller member serving as a fulcrum as a fulcrum. 1 invention).

The above object is also achieved by a fixing belt comprising a first fixing roller member which stretches a belt member on one side, and a roller member which stretches the other side of the belt member together with the first fixing roller member. A second fixing roller member forming a unit, forming a pair with the first fixing roller member, sandwiching the belt member, and pressing the first fixing roller member to form a nip portion; In the fixing device for fixing a toner image on a transfer material, a heating unit that contacts the belt member from the inside of the belt member and heats the belt member between the first fixing roller member and the roller member Is provided in the fixing belt unit, and the second fixing roller is opened with the opening of the fixing belt unit including the heating means, with the first fixing roller member as a fulcrum. Is achieved by the fixing device, wherein (second invention) to release the pressing of the the first fixing roller member la member.

The above object is also achieved by a first fixing roller member which stretches a belt member on one side, a roller member which stretches the other side of the belt member together with the first fixing roller member, and A second fixing roller member that forms a nip with the first fixing roller member with the member interposed therebetween, and a belt member of the belt member is provided between the first fixing roller member and the roller member. In a fixing device for contacting the belt member from the inside and heating the belt member, and fixing the toner image on the transfer material at the nip portion, the fixing device fixes the second end of the rear end of the transfer material passing first. This is achieved by a fixing device (third invention) in which the position on the fixing roller member substantially coincides with the position on the second fixing roller member of the leading end of the transfer material that subsequently passes.

The above object is also achieved by a first fixing roller member which stretches a belt member on one side, a roller member which stretches the other side of the belt member together with the first fixing roller member, A second fixing roller member that forms a nip with the first fixing roller member with the member interposed therebetween, and a belt member of the belt member is provided between the first fixing roller member and the roller member. A fixing device for fixing the toner image on the transfer material at the nip portion, wherein the fixing device fixes the toner image on the transfer material in the nip portion; This is achieved by the fixing device (fourth invention), wherein the upper position and the position on the belt member of the leading end of the transfer material that subsequently passes substantially coincide with each other.

[0012] Further, the object is to provide a first fixing roller member that stretches a belt member on one side, a roller member that stretches the other side of the belt member together with the first fixing roller member, A second fixing roller member forming a nip portion, forming a pair with the first fixing roller member with the member interposed therebetween; and a belt member between the first fixing roller member and the roller member. In a fixing device for fixing a toner image on a transfer material at the nip portion, a heating device for contacting the belt member from the inside and heating the belt member is provided. The position on the roller member and the position on the second fixing roller member of the leading end of the subsequently passing transfer material are displaced by ３ to ／ with respect to the circumference of the second fixing roller member. Is characterized by Is achieved by that a fixing device (fifth invention).

[0013] The above object is also achieved by a first fixing roller member which stretches a belt member on one side, a roller member which stretches the other side of the belt member together with the first fixing roller member, and A second fixing roller member that forms a nip with the first fixing roller member with the member interposed therebetween, and a belt member of the belt member is provided between the first fixing roller member and the roller member. In a fixing device that abuts against the belt member from the inside and heats the belt member, the fixing device fixes the toner image on the transfer material in the nip portion. And a position on the belt member of a leading end of the transfer material passing therethrough is displaced by ３ to ／ of a circumferential length of the belt member. Sixth invention It is achieved by.

[0014]

Embodiments of the present invention will be described below. Note that the description in this column does not limit the technical scope of the claims and the meaning of terms. Further, the following assertive description in the embodiment of the present invention indicates the best mode, and does not limit the meaning or technical scope of the terms of the present invention.

An image forming process and each mechanism of an embodiment of an image forming apparatus using a fixing device according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional configuration view of a color image forming apparatus showing an embodiment of an image forming apparatus using a fixing device according to the present invention, and FIG. 2 is a side cross-sectional view of the image forming body of FIG. FIG. 3 is an explanatory diagram of the structure and setting conditions of the fixing device.

According to FIG. 1 or FIG. 2, a photosensitive drum 10, which is an image forming body, is provided on the outer periphery of a cylindrical substrate formed of a light-transmitting member such as glass or light-transmitting acrylic resin. A photoconductive layer and a photoconductor layer of an organic photosensitive layer (OPC) are formed.

The photosensitive drum 10 is rotated clockwise as indicated by an arrow in FIG. 1 with the light-transmitting conductive layer grounded by power from a driving source (not shown).

In the present invention, the exposure beam for image exposure is
The photoconductor layer of the photoconductor drum 10, which is the image forming point, only needs to have an exposure light amount of a wavelength that can provide an appropriate contrast with respect to the light attenuation characteristic (photocarrier generation) of the photoconductor layer. . Therefore, the light transmittance of the light-transmitting substrate of the photosensitive drum in the present embodiment does not need to be 100%, and may have a characteristic of absorbing a certain amount of light when transmitting the exposure beam. . The point is that any suitable contrast can be provided. As a material of the light-transmitting substrate, an acrylic resin, particularly one obtained by polymerizing a methyl methacrylate monomer, is preferably used because of its excellent light-transmitting properties, strength, accuracy, surface properties, etc. Various translucent resins such as acryl, fluorine, polyester, polycarbonate, polyethylene terephthalate and the like used for the above can be used. Further, as long as it has a light-transmitting property with respect to the exposure light, it may be colored. As the light-transmitting conductive layer, indium tin oxide (I
TO), tin oxide, lead oxide, indium oxide, copper iodide, or a metal thin film of Au, Ag, Ni, Al, or the like that maintains light transmissivity. Reactive deposition method, various sputtering methods, various CV
D method, dip coating method, spray coating method and the like can be used.
Various organic photosensitive layers (OPC) can be used as the photoconductor layer.

The organic photosensitive layer serving as the photosensitive layer of the photoconductor layer includes a charge generation layer (CGL) containing a charge generation material (CGM) as a main component and a charge transport layer (CTM) containing a charge transport material (CTM) as a main component. And CTL). An organic photosensitive layer having a two-layer structure has high durability as an organic photosensitive layer due to its thick CTL and is suitable for the present invention.
The organic photosensitive layer may have a single layer structure containing a charge generation material (CGM) and a charge transport material (CTM) in one layer. ,
Usually, a binder resin is contained.

A scorotron charger 11 as a charging unit described below, and an exposure optical system 1 as an image writing unit will be described.
2. The developing device 13 as a developing unit is prepared for an image forming process for each color of yellow (Y), magenta (M), cyan (C) and black (K), respectively. Are arranged in the order of Y, M, C, and K with respect to the rotation direction of the photosensitive drum 10 indicated by the arrow in FIG.

Scorotron charger 11 as charging means
Is mounted opposite to and close to the photosensitive drum 10 in a direction (perpendicular to the plane of FIG. 1) orthogonal to the moving direction of the photosensitive drum 10 as an image forming body. A control grid (unsigned) maintained at a predetermined potential with respect to the body layer;
As a, for example, a sawtooth electrode is used, and a charging action (minus charging in the present embodiment) is performed by corona discharge having the same polarity as the toner, thereby giving a uniform potential to the photosensitive drum 10. As the corona discharge electrode 11a, a wire electrode or a needle electrode may be used.

The exposure optical system 12 for each color is a linear exposure element (LED) in which a plurality of LEDs (light emitting diodes) as light emitting elements for image exposure light are arranged in an array parallel to the axis of the photosensitive drum 10. (Not shown) and a selfoc lens (not shown) as an equal-magnification imaging element are configured as an exposure unit attached to a holder. Cylindrical holding member 2
At 0, the exposure optical system 12 for each color is attached and housed inside the base of the photosensitive drum 10. In addition, as the exposure element, a linear element in which a plurality of light emitting elements such as FL (phosphor emission), EL (electroluminescence), and PL (plasma discharge) are arranged in an array is used.

An exposure optical system 12 as an image writing means for each color is used to set an exposure position on a photosensitive drum 10 between a scorotron charger 11 and a developing unit 13 and to a developing unit 13 It is arranged inside the photoconductor drum 10 in a state provided on the upstream side in the rotation direction of the drum 10.

The exposure optical system 12 performs image processing based on image data of each color sent from a separate computer (not shown) and stored in a memory, and then forms an image on a uniformly charged photosensitive drum 10. Exposure is performed to form a latent image on the photosensitive drum 10. The emission wavelength of the light-emitting element used in this embodiment is usually 6 for the toners of Y, M, and C, which have high translucency.
The wavelength in the range of 80 to 900 nm is good, but the wavelength may be shorter than this, since the color toner does not have sufficient translucency since image exposure is performed from the back surface.

The developing device 13 as a developing means for each color includes
Inside yellow (Y), magenta (M), cyan (C)
Alternatively, it contains a black (K) two-component (or one-component) developer and is formed of, for example, a cylindrical non-magnetic stainless steel or aluminum material having a thickness of 0.5 to 1 mm and an outer diameter of 15 to 25 mm, respectively. And a developing sleeve 13a as a developer carrier.

In the developing region, the developing sleeve 13a is kept in non-contact with the photosensitive drum 10 by a contact roller (not shown) with a predetermined gap, for example, 100 to 1000 μm, between the developing sleeve 13a and the rotating direction of the photosensitive drum 10. It rotates in the forward direction at the closest position, and at the time of development, an AC voltage AC is superimposed on a DC voltage of the same polarity as the toner (in this embodiment, a negative polarity) or a DC voltage with respect to the developing sleeve 13a. By applying the developing bias voltage, non-contact reversal development is performed on the exposed portion of the photosensitive drum 10. At this time, the accuracy of the development interval needs to be about 20 μm or less in order to prevent image unevenness.

As described above, the developing device 13 transfers the electrostatic latent image formed on the photosensitive drum 10 by the charging by the scorotron charger 11 and the image exposure by the exposure optical system 12 in a non-contact state. Reversal development is performed with toner having the same polarity as the charge polarity of No. 10 (in the present embodiment, the photosensitive drum is negatively charged, and the toner has negative polarity).

As shown in FIG. 2, the photosensitive drum 10 and a holder 20 as an exposure optical system holding member rotatably support the photosensitive drum 10 at the rear and front ends of the apparatus. Drum flanges 10A and 10B as photoconductor drum support members, and optical system flanges 120A and 120B as exposure optical system support members that support holder 20
And are integrally formed via means such as press fitting or screws. The photosensitive drum 10 includes a drum flange 10A as a photosensitive drum support member and a drum flange 1.
0B is the bearing B1 and the bearing B respectively with respect to the shaft 121 and the optical system flange 120B integrated with the optical system flange 120A of the holder 20.
It is rotatably supported via 2.

The shaft 121 has a shaft portion 121A for holding the photoreceptor drum 10, and a support shaft 130 as shaft holding means having an engagement hole 130A is provided on the rear device board 70. The linear bearing B4 is fitted in the engagement hole 130A, and the receiving member 130
The support shaft 130 is fixed to the device substrate 70 on the rear side by screws or the like with the a interposed therebetween. The support shaft 130 is located at the center of the gear G2 that meshes with the drive gear G1, and rotatably supports a conductive member 131 that integrates the gear G2 via a bearing B3. On the other hand, an opening 70A is formed in the apparatus substrate 70 on the front side of the apparatus so that the photosensitive drum 10 having the exposure optical system 12 fixed to the holder 20 can be inserted and removed.

The holder 20 inserts the shaft portion 121A of the shaft 121 into the linear bearing B4 provided on the support shaft 130 with respect to the device board 70 on the back side, and the shaft portion 121A
The engaging pin 121P inserted into the
The exposure optical system 12 is attached by regulating the angular relation position of the exposure optical system 12 by engaging with a V-shaped groove formed on the front side of the exposure optical system 12. The optical system flange 120C, which is a support member, is
With the front lid 120D pressed in the axial direction.
It is mounted at a predetermined position by fixing with.

A coupling 10C attached to a side surface of a drum flange 10A which is a photosensitive drum supporting member for supporting the photosensitive drum 10, a drive pin 131A attached to a side surface of a conductive member 131 integrated with a gear G2, and a set screw 51, the drum flange 10A and the gear G2
When the photosensitive drum 10 having the holder 20 is integrated, the drum flange 10
A coupling 10C attached to the side of A is a drive pin 1 attached to the side of a conductive member 131 having a gear G2.
31A, and after engagement, the photoconductive drum 1 having the conductive member 131 having the gear G2 and the drum flange 10A
With the center and the outer peripheral surface aligned, the drive pin 131 is set from the side of the photosensitive drum 10 using the set screw 51.
A and the coupling 10C are fixed, and the drum flange 1
0A and the gear G2 are connected and fixed.

When the image forming body drive motor (not shown) is started by the start of image formation, the rotational power of the drive gear G1 is transmitted to the photosensitive drum 10 via the coupling portion by the gear G2, and the photosensitive drum 10 is moved to the position shown in FIG. , And at the same time, application of a potential to the photosensitive drum 10 is started by the charging action of the Y scorotron charger 11.
After a potential is applied to the photosensitive drum 10, exposure by the first color signal, that is, an electric signal corresponding to the Y image data is started in the Y exposure optical system 12, and the surface of the photosensitive drum 10 is rotated by the rotational scanning. An electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer. The latent image is reversely developed in a non-contact state by the Y developing device 13, and a yellow (Y) toner image is formed on the photosensitive drum 10.

Next, the photoreceptor drum 10 places an M scorotron charger 11 on the yellow (Y) toner image.
Is given a potential by the charging action of the M exposure optical system 12
Exposure is performed using an electrical signal corresponding to the second color signal of m, i.e., magenta (M) image data.
Yellow (Y) by non-contact reversal development
The toner image of magenta (M) is formed on the toner image of FIG.

By the same process, the cyan (C) toner image corresponding to the third color signal is further obtained by the C scorotron charger 11, the exposure optical system 12 and the developing device 13, and the K scorotron charger 11. , Exposure optical system 1
A black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed by the second and developing units 13, and a color toner image is formed on the peripheral surface within one rotation of the photosensitive drum 10. You.

As described above, in this embodiment, Y, M,
Exposure of the organic photosensitive layer of the photoconductor drum 10 by the C and K exposure optical systems 12 is performed through a transparent substrate from inside the photoconductor drum 10. Therefore, the exposure of the images corresponding to the second, third, and fourth color signals can form an electrostatic latent image without being shielded by the previously formed toner image, which is preferable. Photoconductor drum 1
0 may be exposed from outside.

On the other hand, the recording paper P as a transfer material is sent out from a paper feed cassette 15 as a transfer material storage means by a feed roller (no code) and fed by a feed roller (no code) to a timing roller. It is conveyed to 16.

The recording paper P is synchronized with the color toner image carried on the photosensitive drum 10 by the driving of the timing roller 16, and the paper charger 1 as a paper charging means is synchronized.
Due to the electrification of 50, the toner is attracted to the conveyor belt 14a and fed to the transfer area. The recording paper P, which has been closely transported by the transport belt 14a, is moved around the photosensitive drum 10 by a transfer unit 14c as a transfer unit to which a voltage having a polarity opposite to that of the toner (positive polarity in this embodiment) is applied in a transfer area. The color toner images on the surface are collectively transferred to the recording paper P.

The recording paper P on which the color toner image has been transferred is
The paper is discharged by a paper separation AC neutralizer 14h as a transfer material separating unit, separated from the transport belt 14a, and transported to the fixing device 700.

A first fixing roller 17a as a first fixing roller member on one side, a stretching roller 17A as a roller member on the other side, and a first fixing roller 17a and a stretching roller 17A. A fixing belt unit BU1 is formed by the fixing belt 27A as a fixing belt member, and the fixing belt unit BU1 faces the first fixing roller 17a with the fixing belt 27A interposed therebetween (in pairs).
The second fixing roller 17b as a second fixing roller member provided and the guide plate 173 constitute a fixing device 700. If necessary, a halogen lamp HL1 or a xenon lamp (not shown) serving as a heat ray irradiating means for emitting heat rays such as infrared rays or far infrared rays for heating the stretch roller 17A is provided inside the stretch roller 17A as a roller member. ) Is provided, and a tension roller 17A having a heat ray irradiation means therein is used as a heat roller member. Also,
A heating element unit 170 having a ceramic heater 171 as a heating element and heating the fixing belt 27A as a planar fixed heating element contacts (contacts) the inside of the fixing belt 27A and contacts the fixing belt unit BU1. Provided. A nip portion N is formed between the first fixing roller 17a and the second fixing roller 17b with the fixing belt 27A interposed therebetween. A guide plate 173 is provided below the fixing belt 27A to guide the recording paper P as a transfer material to the nip portion N and receive heat from the fixing belt 27A to form a preheating area.

While receiving the residual heat from the guide plate 173 and the heat from the upper fixing belt 27A, the recording paper P is conveyed by being guided by the heated guide plate 173, and the recording paper P and the toner image on the recording paper P are conveyed. Is preheated while the nip portion N between the fixing belt 27A and the second fixing roller 17b.
The recording paper P enters the nip N and is heated by the heat of the fixing belt 27A and pressed by the first fixing roller 17a and the second fixing roller 17b.
The upper color toner image is fixed.

The recording paper P on which the color toner image has been fixed is sent by a paper discharge roller 18 and discharged to a tray at the top of the apparatus.

The toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is transferred to a cleaning blade 19 provided in a cleaning device 19 as an image forming body cleaning means.
Cleaning is performed by a. The photosensitive drum 10 from which the residual toner has been removed is uniformly charged by the scorotron charger 11, and enters the next image forming cycle.

As shown in FIG. 3, a first fixing roller 17a as a first fixing roller member on one side, a tension roller 17A as a roller member on the other side, a first fixing roller 17a and a tension roller A fixing belt unit BU1 is formed by a fixing belt 27A as a belt member stretched over the setting roller 17A, and the fixing belt unit BU1 and
The fixing device 700 is configured by a second fixing roller 17b as a second fixing roller member provided opposite to (as a pair with) the first fixing roller 17a with the fixing belt 27A interposed therebetween, and a guide plate 173.

If necessary, a halogen lamp HL1 or a xenon lamp as a heat ray irradiating means for emitting heat rays such as infrared rays or far infrared rays for heating the stretch roller 17A is provided inside the stretch roller 17A as a roller member. (Not shown) is provided, and a tension roller 17A having a heat ray irradiation unit therein is used as a heat roller member.

Further, a fixing belt 27A as a belt member provided in the fixing belt unit BU1 is provided between the heating roller 17A and the first fixing roller 17a on the transport side of the recording paper P, and inside the fixing belt 27A ( Fixing belt 27
A, which has a width corresponding to the maximum transfer material size to be used, which is a planar shape in which a ceramic heater 171 as a heating element and a heater holder 172, which are in contact with (contact with) the fixing belt 27A, are integrated. A heating element unit 170 as a rectangular fixed heating element is provided. The heating unit 170 heats the fixing belt 27A. In this case, the ceramic heater 171 as the heating element does not necessarily need to directly contact the fixing belt 27A, and may be configured to contact the fixing belt 27A via the heater holder 172.

A heating element unit 170 as a planar fixed heating element inside the fixing belt unit BU1 is provided.
The heater holder 172 and the ceramic heater 171 have a radius of curvature R on the contact surface side (contact surface side) of 100 to 1000 mm.
A wide belt member heating region (contact surface) is formed to contact (contact) the fixing belt 27A as a belt member. Heater holder 172 provided on heating element unit 170 and fixing belt 27A of ceramic heater 171
In the case of a configuration in which the ceramic heater 171 is not in direct contact with the fixing belt 27A,
The contact surface (contact surface) of the heater holder 172 with the fixing belt 27A is preferably subjected to a fluorine coating process of about 5 to 20 μm to improve the sliding with the fixing belt 27A. It is preferable to apply a fluorine coating process to the inside (inner peripheral surface) of the fixing belt 27A in order to improve the sliding of the fixing belt 27A.

A fixing belt 27A as a belt member
Is provided with a fixing separation claw TR3, a fixing oil cleaning roller TR1, and an oil application roller TR2 in the rotation direction of the fixing belt 27A from the position of the nip portion N, and a felt member impregnated with oil is provided by a cylindrical aluminum pipe or the like. Oil is applied to the fixing belt 27A by an oil application roller TR2 wound around a paper tube or the like. The oil on the peripheral surface of the fixing belt 27A is cleaned by the fixing oil cleaning roller TR1.

The fixing belt 27A as a belt member has an inner diameter of about 80 to 150 mm and a thickness of 20 mm as a base.
On the outside (outer peripheral surface) of a metal belt using, for example, a nickel electroformed belt having a thickness of about 30 to 300 μm.
One coated with about m of insulating silicon rubber is used.

As the tension roller 17A as a roller member, the outer side (outer peripheral surface) of a metal pipe using an aluminum material having an outer diameter of about 20 to 40 mm and a thickness of about 0.5 to 2 mm.
Which is coated with a fluororesin having a thickness of about 10 to 100 μm. If necessary, a halogen lamp HL1 or a xenon lamp (not shown) serving as a heat ray irradiating means for emitting heat rays such as infrared rays or far infrared rays for heating the tension roller 17A is provided inside the tension roller 17A as a roller member. ) Is provided, and a tension roller 17A having a heat ray irradiation means therein is used as a heat roller member.

Ceramic heater 171 as heating element
Is formed integrally with the heater holder 172 in a state of being in contact with or not in contact with the fixing belt 27A to form the heating element unit 170, and has a thickness of about 0.5 to 2 mm.
An alumina substrate having a width of about 25 mm (width in the moving direction of the fixing belt 27A) is provided with a resistance heating layer and a 10 μm-thick overcoat glass as a surface protection layer sequentially by thick film printing. Used. The ceramic heater 17 is made of overcoat glass as a surface protection layer.
1, the thermal resistance between the fixing belts 27A is reduced. The surface protective layer also functions to protect the resistance heating layer and prevent the fixing belt 27A from being worn. When the ceramic heater 171 is in contact with the fixing belt 27A, a smooth surface such as a fluorine coat is provided on at least the contact surface of the ceramic heater 171 with the fixing belt 27A.
The rotation with the fixing belt 27A is facilitated. The ceramic heater 171 as a heating element provided in the heating element unit 170 as a planar fixed heating element having a wide contact surface with the fixing belt 27A enables responsive heating of the fixing belt 27A.

The heater holder 172 holding the ceramic heater 171 has a width of 10 to 100 mm, preferably 30 to 100 mm.
Approximately 70 mm, and is formed of a metal member having good thermal conductivity using, for example, aluminum or iron. At the same time, it serves as a running guide for the fixing belt 27A. Heater holder 172
A smooth surface such as a fluorine coat is provided on at least the contact surface with the fixing belt 27A to facilitate the rotation with the fixing belt 27A.

The first fixing roller 17a as the upper first fixing roller member is provided with a foamed silicone rubber layer (unsigned) on the outer side (outer peripheral surface) of a metal pipe (unsigned) having an outer diameter of about 10 to 15 mm. It is a low-hardness sponge roller (soft roller) having an outer diameter of about 15 to 25 mm and a rubber hardness of 20 to 60 Hs (JIS, A rubber hardness).

The second fixing roller 17b serving as a second fixing roller member for pressing the first fixing roller 17a with the fixing belt 27A interposed therebetween is provided outside a metal pipe (not numbered) having an outer diameter of about 15 to 20 mm (not shown). Surface), outer diameter 15-2
Approximately 5mm, rubber hardness 40Hs-80Hs (JI
(S, A rubber hardness) provided with a silicone rubber layer (no symbol), and is formed as a hard roller harder than the first fixing roller 17a.

The upper side is convex between the first fixing roller 17a as a soft roller and the second fixing roller 17b as a hard roller, with a width of 10 mm or less, preferably 5 mm or more, across the fixing belt 27A. A relatively narrow nip N is formed. As a result, the curvature of the first fixing roller 17a on the exit side of the recording paper P in the nip portion N becomes large, and the separation of the recording paper P after fixing the toner image is performed satisfactorily.

A metal guide plate 173 using, for example, an aluminum plate or a stainless steel plate for guiding the recording paper P to the nip portion N is provided below the ceramic heater 171 and below the fixing belt 27A. As it approaches the nip N from about 5 to 15 mm of the opening on the entrance side of
The intervals gradually become narrow, and the guide plate 173 is heated by receiving heat from the fixing belt 27A heated by the heating element unit 170 in which the ceramic heater 171 is integrated,
A wide preheating area for preheating the toner image is formed between the fixing belt 27A and the fixing belt 27A.

The TS1 is provided with a tension roller 17A if necessary.
In the case where a halogen lamp HL1 or a xenon lamp (not shown) as a heat ray irradiating means is provided therein, temperature control of heating the stretching roller 17A by the halogen lamp HL1 or a xenon lamp (not shown) as a heat ray irradiating means is performed. Is a temperature sensor as a temperature detecting means using, for example, a contact-type thermistor. TS2 is embedded in the heater holder 172 provided in the heating element unit 170 on the downstream side of the ceramic heater 171 in the moving direction of the fixing belt 27A. Is a temperature sensor as a temperature detecting means using, for example, a contact-type thermistor for controlling the temperature of the ceramic heater 171 as a heating element which is fixed and is in contact with the fixing belt 27A as a belt member. Control the temperature attached to the second fixing roller 17b on the side. A temperature sensor as a temperature detecting means using, for example, contact type thermistor fit, T
S4 is a temperature sensor mounted on the lower guide plate 173 as temperature detecting means using a contact-type thermistor for performing temperature control. Temperature sensor TS
As TS1, TS2, TS3, and TS4, a non-contact type can be used in addition to a contact type.

The guide plate 173 is heated by the heat from the fixing belt 27A which is heated by the heating element unit 170 in which the ceramic heater 171 is integrated. While receiving the heat from the upper fixing belt 27A, the recording paper P is guided by the heated guide plate 173 and is conveyed.
While the toner image on the recording paper P is being melted, the nip portion N between the fixing belt 27A and the second fixing roller 17b has a width of 10 mm or less, and preferably 5 mm or more. And enters the nip N
Heating of the fixing belt 27A by heat and the first fixing roller 1
7a and the pressure by the second fixing roller 17b,
The toner image on the recording paper P is fixed.

By the fixing device 700 described with reference to FIG. 3, the transfer material and the toner image on the transfer material are heated in advance by the belt member heated by the heating of the fixed heating element and the heated guide plate. (Preliminary heating) and fixing at the nip portion, so that the warming-up time is shortened, and the temperature of the belt member having poor thermal conductivity is accelerated by the fixed heating element that contacts (contacts) the belt member. The warm-up time is reduced. Further, the heating by the heating roller member and the fixed heating element using the heat ray irradiating means eliminates the temperature change and the temperature non-uniformity of the belt member during the continuous printing, thereby obtaining a good fixing property with less fixing unevenness. In addition, a fixing device having high-speed capability can be provided. Further, in the initial stage of heating, it is necessary to raise the temperature of the first fixing roller member and the second fixing roller member in the nip portion via the belt member, and the temperature of the belt member has not reached a fixing temperature. Therefore, as described above, the fixed heating element is set to be responsive, and assists in increasing the temperature of the belt member at the beginning of heating.

However, in order to further increase the temperature of the belt member having poor thermal conductivity and shorten the warming-up time, and to further prevent the belt member temperature change and the temperature nonuniformity during the continuous printing, the tension is increased. Bridge roller 17
It is preferable to provide a heat ray irradiation means inside A and set the following conditions.

First, first, the heat capacity (Q1) of the stretching roller 17A as a roller member having a heat ray irradiating means inside.
(J / deg)) to the heat capacity (Q2 (J / d) of the heating element unit 170 as a fixed heating element in which the ceramic heater 171 as the heating element and the heater holder 172 are integrated.
eg)) (Q1> Q2). As a result, the fixing belt 27A having poor heat conductivity
, The warming-up time is shortened, and the temperature change and the temperature non-uniformity of the fixing belt 27A during continuous printing are eliminated, so that a fixing device having good fixing properties can be realized.

More specifically, when the heat capacity of the tension roller 17A having the heat ray irradiating means inside is Q1 (J / deg) and the heat capacity of the heating element unit 170 is Q2 (J / deg), the heat ray irradiating means is used. It is preferable to set the ratio of the heat capacity Q1 of the stretching roller 17A provided therein to the heat capacity Q2 of the heating element unit 170, Q1 / Q2, as Q1 / Q2 = 1.5-10. It is preferable that the heat capacity Q1 of the stretching roller 17A having the heat ray irradiation means therein be large, and the heat capacity Q2 of the heating element unit 170 be small. Heat capacity Q1 of stretching roller 17A having heat ray irradiation means inside
This is because a sufficient heat capacity is required to sufficiently warm the fixing belt 27A, whose temperature has significantly decreased after fixing. The role of this heat reservoir is fulfilled by the stretching roller 17A having the heat ray irradiating means inside, while the heating element unit 170 fulfills the role of temperature control utilizing good responsiveness. The heat capacity Q2 of the heating element unit 170 is too large, and the ratio of the heat capacity Q1 of the tension roller 17A having the heat ray irradiation means to the heat capacity Q2 of the heating element unit 170, Q1 / Q2, is 1.
If it is less than 5, the heating time of the heating element unit 170 by the ceramic heater 171 becomes longer, and the responsiveness is reduced. The temperature control of the fixing belt 27A becomes insufficient. Also, the heat capacity Q2 of the heating element unit 170 is too small,
The ratio of the heat capacity Q1 of the tension roller 17A having the heat ray irradiation means to the heat capacity Q2 of the heating element unit 170, Q1
If / Q2 exceeds 10, the heat capacity of the heating element unit 170 is insufficient, and the fixing belt 27A cannot be sufficiently heated.

By setting the above conditions in the fixing device 700 described with reference to FIG. 3, the belt member heated by the heating by the roller member having the heat ray radiating means and the fixed heating element and the belt member heated by the heating member are heated. Since the toner image on the transfer material is melted in advance by the guide plate and fixed at the nip portion, the warm-up time is shortened, and the heating by the roller member having the heat ray irradiation means inside and the fixed heating element is performed. Thereby, the temperature rise of the belt member having poor thermal conductivity is further accelerated, and the warm-up time is further reduced.
In addition, for a fixed heating element having a small heat capacity, a roller member having a heat ray irradiating means therein, which increases the heat capacity on the upstream side of the nip portion, serves as a heat reservoir, and stabilizes the temperature of the belt member during continuous printing. In addition to this, a large pre-heating area for pre-heating the toner image is provided at the bottom while the fixed heating element with a small heat capacity allows the temperature of the belt member entering the nip during continuous printing to be responsively warmed. In addition, the temperature change and non-uniformity of the temperature of the belt member at the time of continuous printing are more eliminated, and a good fixing property with less fixing unevenness can be obtained, and a high-speed compatible fixing device can be provided. Further, in the initial stage of heating, the first fixing roller member and the second fixing roller member in the nip portion through the belt member are not sufficiently heated, so that the belt member does not reach a fixing temperature. Also in this case, the warming-up time can be substantially reduced by setting the fixed heating element to have a responsive setting as described above and assisting the temperature rise of the belt member at the beginning of heating. In addition, during continuous printing, even if the temperature of the belt member fluctuates due to the heating by the roller member having the heat ray irradiating means therein, the belt member at the nip portion is responsively heated by the fixed heating element downstream. The temperature can be adjusted to be constant. Further, the fixing temperature setting condition can be changed in accordance with the type of the transfer material by changing the temperature setting of the fixed heating element.

Second, the surface temperature T1 (° C.) of the stretching roller 17A as a roller member having a heat ray irradiation means inside.
When the surface temperature of the heating element unit 170 as a fixed heating element is T2 (° C.), it is preferable to set T1 ≦ T2. Downstream heating element unit 1
It is preferable that a high heat supply is performed at 70 so that the front surface of the fixing belt 27A has a high temperature distribution with respect to the back surface so as to have responsiveness, and T1 ≦ T2. Usually, the surface temperature T1 of the stretching roller 17A having the heat ray irradiation means inside is:
This is the fixing temperature when the fixing temperature of thin paper etc. needs to be low.
The temperature is maintained at about 150 to 180 ° C., and the surface temperature T2 of the heating element unit 170 is kept equal to or higher than the surface temperature T1 of the stretching roller 17A having the heat ray irradiation means inside.

More specifically, the surface temperature T2 of the heating element unit 170 and the tension roller 1 having the heat ray irradiation means inside
It is preferable to set the ratio of the surface temperature 7A to the surface temperature T1, T2 / T1, such that T2 / T1 = 1.05 to 1.25. The surface temperature T2 of the heating element unit 170 is too low, and the surface temperature T2 of the heating element unit 170 and the tension roller 17 having the heat ray irradiating means therein.
If the ratio of A to the surface temperature T1, T2 / T1, is less than 1.05, the fixing belt 27 by the heating element unit 170 is used.
No responsive control of A heating is provided. The surface temperature T1 of the stretching roller 17A having the heat ray irradiating means therein is too low, so that the surface temperature T2 of the heating element unit 170 and the surface temperature T1 of the stretching roller 17A having the heat ray irradiating means therein.
When the ratio T2 / T1 exceeds 1.25, the fixing belt 27A is not sufficiently heated by the stretching roller 17A having the heat ray irradiating means therein, and fixing defects such as uneven fixing are caused.

By setting the above-described conditions in the fixing device 700 described with reference to FIG. 3, the belt member heated by the heating by the roller member having the heat ray radiating means and the fixed heating element and the belt member heated by the fixed heating element are heated. The toner image on the transfer material is preliminarily heated (preheated) by the guide plate and is fixed at the nip portion, so that the warm-up time is shortened, and a roller member having a heat ray irradiating means therein and a fixed heating element are provided. By the heating of the above, the temperature of the belt member having poor thermal conductivity is increased more quickly, and the warm-up time is further reduced. Further, a roller member having a heat ray irradiating means therein functions as a heat reservoir, which stabilizes the temperature of the belt member during continuous printing, and provides a wide preheating area for preheating the toner image. The temperature of the belt member entering the nip portion at the time of continuous printing is promptly warmed by the fixed heating element having a substantially high temperature rising speed (the temperature control of the belt member is performed with good response),
The change in the temperature and unevenness of the temperature of the belt member during the continuous printing are further eliminated, so that a good fixing property with less fixing unevenness can be obtained, and a fixing device having high-speed capability can be provided. In addition, even if the heating rate of the fixed heating element is substantially high, at the beginning of heating, the first nip portion of the nip portion is interposed via the belt member.
The temperatures of the fixing roller member and the second fixing roller member are not sufficiently increased, and the temperature of the belt member has not reached a fixing temperature. In this case, as described above, the warming-up time is substantially reduced by setting the heating rate of the fixed heating element to be high and setting the temperature of the fixed heating element to be high to assist the heating of the belt member at the beginning of heating. Can be shortened. In addition, during continuous printing, even if the temperature of the belt member fluctuates due to the heating by the roller member having the heat ray irradiating means therein, the belt member at the nip portion is responsively heated by the fixed heating element downstream. The temperature can be adjusted to be constant. Further, the fixing temperature setting condition can be changed in accordance with the type of the transfer material by changing the temperature setting of the fixed heating element.

Third, tension roller 1 as a roller member
The maximum power consumption (W1 (W)) of a halogen lamp HL1 or a xenon lamp (not shown) as a heat ray irradiating means provided inside 7A is converted into a ceramic as a heating element provided in a heating element unit 170 as a fixed heating element. It is preferable that the power consumption is set to be larger than the maximum power consumption (W2 (W)) of the heater 171 (W1> W2). The sum of the respective maximum power consumptions that can be consumed for normal fixing, W1 + W2, is limited to about 0.8 to 1.2 kW due to usage conditions as a printer function.

Halogen lamp HL as heat ray irradiation means
1 or xenon lamp (not shown)
(W)) is set to be larger than the maximum power consumption (W2 (W)) of the ceramic heater 171 as the heating element (W).
1> W2), it is possible to supply sufficient electric power to the stretching roller 17A having a heat ray irradiating means inside and serving as a heat reservoir.

Specifically, when the maximum power consumption of the halogen lamp HL1 or xenon lamp (not shown) is W1 (W) and the maximum power consumption of the ceramic heater 171 is W2 (W), the halogen lamp HL1 or the xenon lamp is not used. It is preferable to set the ratio W1 / W2 between the maximum power consumption W1 (not shown) and the maximum power consumption W2 of the ceramic heater 171 as follows: W1 / W2 = 1.5-5. It is preferable that the maximum power consumption W1 of the stretching roller 17A having the heat ray irradiation means inside is large and the maximum power consumption W2 of the ceramic heater 171 is small. Stretch roller 17A having heat ray irradiation means inside
Is too small, the ratio of the maximum power consumption W1 of the stretching roller 17A having the heat ray irradiation means to the maximum power consumption W2 of the ceramic heater 171 is W1 / W.
If the value of 2 is less than 1.5, heating of the stretching roller 17A having the heat ray irradiating means therein is insufficient, and the fixing belt 27A whose temperature has decreased after fixing is not sufficiently warmed. Further, the maximum power consumption W2 of the ceramic heater 171 is too small, and the maximum power consumption W1 of the stretching roller 17A having the heat ray irradiation means inside and the maximum power consumption W2 of the ceramic heater 171 are increased.
When the ratio W1 / W2 exceeds 5, the ceramic heater 171 cannot sufficiently heat the fixing belt 27A with responsiveness.

As described above, the maximum power consumption W1 (W) of the stretching roller 17A having the heat ray irradiation means therein is determined by the maximum power consumption W1 of the ceramic heater 171 as a fixed heating element.
2 (W1> W2), and the temperature rise of the ceramic heater 171 is preferably accelerated.

For this reason, the heat capacity of the stretching roller 17A as a roller member having a heat ray irradiating means therein is set to Q1 (J
/ Deg), when the heat capacity of the heating element unit 170 as a fixed heating element in which the ceramic heater 171 as the heating element and the heater holder 172 are integrated is Q2 (J / deg), the maximum power consumption W2 of the ceramic heater 171
Of the heat capacity Q2 of the heating element unit 170 and W2 / Q
2, the halogen lamp H inside the tension roller 17A
The ratio W1 / Q1 between L1 and the maximum power consumption W1 of the xenon lamp (not shown) and the heat capacity Q1 of the stretching roller 17A having the heat ray irradiation means therein is set as follows: (W2 / Q2)> (W1 / Q1) Is preferred.

That is, (W2 / Q2) is the value of the heating element unit 1 in the heating element unit 170 itself (in a state of the heating element unit 170 alone and separated from the fixing belt 27A).
(W1 / Q1) is the tension roller 17A having the heat ray irradiating means inside (the tension roller having the heat ray irradiating means inside, separated from the fixing belt 27A) 17A alone (in the state of a single unit 17A), and the substantial heating rate (W2 / Q2) of the heating element unit 170 is substantially the same as that of the stretching roller 17A having the heat ray irradiation means inside. Heating rate (W1 / Q1)
Is preferably set quickly ((W2 / Q2)> (W1 / Q1)).

Specifically, it is preferable to set (W2 / Q2) / (W1 / Q1) = 2-7. Originally heating element unit 170
The temperature rise rate (W1 / Q1) of the tension roller 17A having the heat ray irradiating means therein is increased while increasing the substantial temperature rise rate (W2 / Q2) of the heat ray irradiating means. Roller 17 having a large heat capacity Q1 and
A slows down. A substantial heating rate (W2 / Q2) of the heating element unit 170 is slow (small), and a stretch having the substantial heating rate (W2 / Q2) of the heating element unit 170 and heat ray irradiation means inside. The ratio of the roller 17A to the substantial heating rate (W1 / Q1), (W2 / Q2) / (W1
/ Q1) is the fixing belt 27 in the heating element unit 170.
A is preferably 2 or more from the viewpoint of the substantial responsiveness of the temperature rise rate of A.
Further, the substantial heating rate (W1 / Q1) of the stretching roller 17A having the heat ray irradiation means inside is slow (small), and the substantial heating rate (W2
/ Q2) and a stretching roller 17 having heat ray irradiation means inside
Ratio of A to a substantial heating rate (W1 / Q1), (W2 /
When (Q2) / (W1 / Q1) exceeds 7, the temperature rise of the fixing belt 27A becomes faster, but the heat capacity Q2 of the heating element unit 170 with respect to the fixing belt 27A is too small, and the temperature of the fixing belt 27A becomes improper. Become stable. Further, even if the speed is excessively high, it is not effective because there is time for heat conduction from the back surface to the front surface of the fixing belt 27A, and a value of 7 or less is sufficient.

By setting the above-described conditions in the fixing device 700 described with reference to FIG. 3, the belt member heated by the roller member having the heat ray radiating means and the fixed heating element, and the belt member heated by the fixed heating element are heated. The toner image on the transfer material is preliminarily heated (preheated) by the guide plate and is fixed at the nip portion, so that the warm-up time is shortened, and a roller member having a heat ray irradiating means therein and a fixed heating element are provided. By the heating of the above, the temperature of the belt member having poor thermal conductivity is increased more quickly, and the warm-up time is further reduced. Also, for a fixed heating element having a small heat capacity and a maximum power consumption, a roller member having a heat ray irradiating means therein for increasing the heat capacity and the maximum power consumption on the upstream side of the nip portion serves as a heat reservoir, and performs continuous printing. In addition to keeping the temperature of the belt member stable at the time, it has a wide pre-heating area for pre-heating the toner image, and the fixed heating element with a substantially high heating rate allows the nip part to be continuously printed. The temperature of the entering belt member is responsively warmed (the temperature control of the belt member is performed with good responsiveness), and the temperature change and the temperature non-uniformity of the belt member during continuous printing are further eliminated, and there is little fixing unevenness. And a fixing device having high-speed capability can be obtained. In addition, even if the heating rate of the fixed heating element is substantially high, at the beginning of heating, the first nip portion of the nip portion is interposed via the belt member.
The temperatures of the fixing roller member and the second fixing roller member are not sufficiently increased, and the belt member has not reached a temperature at which fixing can be performed. In this case, as described above, the warming-up time is substantially reduced by setting the heating rate of the fixed heating element to be high and setting the temperature of the fixed heating element to be high to assist the heating of the belt member at the beginning of heating. Can be shortened. In addition, during continuous printing, even if the temperature of the belt member fluctuates due to the heating by the roller member having the heat ray irradiating means therein, the belt member at the nip portion is responsively heated by the fixed heating element downstream. The temperature can be adjusted to be constant. Further, the fixing temperature setting condition can be changed in accordance with the type of the transfer material by changing the temperature setting of the fixed heating element.

Fourth, the setting of the third substantial heating rate is defined, and a halogen lamp HL1 or a xenon as a heat ray irradiating means provided inside a tension roller 17A as a roller member is provided. The tension roller 17A alone (fixing belt 27) heated by a lamp (not shown)
In the state of the stretching roller 17A alone having the heat ray irradiating means inside and apart from the heating roller A, the heating rate of the heating element (S1 (deg / sec)) is higher than that at the fixing belt 27A contact surface position (S1 (deg / sec)). Ceramic heater 171 and heater holder 17
Heating element unit 1 as a fixed heating element integrated with 2
The temperature rising speed (S2 (deg / sec)) of the heating unit 70 alone (at the position of the contact surface of the fixing belt 27A with the heating element unit 170 alone separated from the fixing belt 27A) is set to be faster. Is preferred.

Specifically, the heating rate S is set to a time Δt (se
c) is determined by the temperature rise temperature ΔT (°) (S = ΔT / Δt), and the temperature rise rate of the stretching roller 17A as the roller member having the heat ray irradiation means is S1 (deg / sec).
c) When the heating rate of the heating element unit 170 as a fixed heating element is S2 (deg / sec), it is preferable to set S2 / S1 = 2 to 7. Originally heating element unit 170
The temperature rising speed S2 of the tension roller 17A having the heat ray irradiating means therein is increased while increasing the temperature rising speed S2 of
1 is slowed down by a stretching roller 17A having a large heat capacity Q1 and a heat ray irradiation means inside. Heating element unit 1
70 is slow (small), and the ratio of the heating rate S2 of the heating element unit 170 to the heating rate S1 of the stretching roller 17A having a heat ray irradiating means therein, S2 / S1
Is preferably 2 or more because the responsiveness of the heating rate of the fixing belt 27A in the heating element unit 170 is lost.
Further, the temperature rising speed S1 of the stretching roller 17A having the heat ray irradiating means therein is slow (small), and the heating unit 1
When the ratio of the heating rate S2 of S70 to the heating rate S1 of the stretching roller 17A having the heat ray irradiating means therein, that is, S2 / S1 is more than 7, the temperature of the fixing belt 27A increases at a high speed,
The heat capacity Q1 of the tension roller 17A having the heat ray irradiating means inside the fixing belt 27A is too small, and the temperature of the fixing belt 27A becomes unstable. Further, even if the speed is excessively high, it is not effective because there is time for heat conduction from the back surface to the front surface of the fixing belt 27A, and a value of 7 or less is sufficient.

By setting the above conditions in the fixing device 700 described with reference to FIG. 3, the belt member heated by the heating by the roller member having the heat ray radiating means and the fixed heating element, and the belt member heated by the fixed heating element are heated. Since the toner image on the transfer material is pre-heated and fixed at the nip by the guide plate, the warm-up time is shortened, and the heating by the roller member having the heat ray irradiation means inside and the fixed heating element is performed. Thereby, the temperature rise of the belt member having poor thermal conductivity is further accelerated, and the warm-up time is further reduced.
In addition, for a fixed heating element having a high heating rate, a roller member having a heat ray irradiating means on the upstream side of a nip portion having a low heating rate serves as a heat reservoir, and the temperature of the belt member during continuous printing is increased. The temperature of the belt member entering the nip during continuous printing is quickly and responsively controlled by the fixed heating element having a high temperature rising rate, while the temperature of the belt member is quickly controlled (the temperature control of the belt member is performed with good response). The temperature change and uneven temperature of the belt member during continuous printing are more eliminated, and good fixing performance with less fixing unevenness is obtained.
Further, a fixing device having high-speed capability can be provided. Also,
Since the fixed heating element has a wide preheating area for preheating the toner image, heating of the belt member is easy, and temperature control is facilitated by increasing the rate of temperature rise of the fixed heating element. Further, even if the heating rate of the fixed heating element is high, the temperature of the first fixing roller member and the second fixing roller member in the nip portion is not sufficiently increased via the belt member at the initial stage of heating, and the belt member is not fixed. Not at a possible temperature. Also in this case, as described above, the warming-up time is increased by setting the heating rate of the fixed heating element to be high and by setting the temperature of the fixed heating element to be high to assist in increasing the temperature of the belt member at the beginning of heating. Can be substantially reduced. In addition, during continuous printing, even if the temperature of the belt member fluctuates due to the heating by the roller member having the heat ray irradiating means therein, the belt member at the nip portion is responsively heated by the fixed heating element downstream. The temperature can be adjusted to be constant. Further, the fixing temperature setting condition can be changed in accordance with the type of the transfer material by changing the temperature setting of the fixed heating element.

However, in the fixing device 700, there is a problem that it is difficult to remove the jam at the nip portion of the transfer material.

Therefore, a method for facilitating the jam processing of the transfer material at the nip portion in the fixing device of FIG. 3 will be described with reference to FIG. 4 or FIG. FIG. 4 is an explanatory diagram of a first example of the jam processing of the transfer material in the nip portion.
FIG. 8 is an explanatory diagram of a second example of the jam processing of the transfer material in the nip portion.

According to FIG. 4, similarly to the description of FIG. 3, the fixing device includes a first fixing roller 17a as a first fixing roller member on one side and a tension member as a roller member on the other side. A fixing belt unit BU1 is formed by the fixing roller 17A, a fixing belt 27A as a belt member stretched around the first fixing roller 17a and the tension roller 17A, and the fixing belt unit BU1 and the fixing belt 27A are sandwiched therebetween. 1 facing the fixing roller 17a (in pairs)
The second fixing roller 17b as a second fixing roller member provided and the guide plate 173 constitute a fixing device 700. If necessary, a halogen lamp HL1 (see FIG. 3 and FIG. 3) is provided inside the stretching roller 17A as a roller member to heat the stretching roller 17A and emit heat rays such as infrared rays or far infrared rays. 4, a xenon lamp (not shown) is provided, and a stretching roller 17A having a heat ray irradiation means inside is used as a roller member having a heat ray irradiation means inside. Further, a heating element unit 170 having a ceramic heater 171 as a heating element and serving as a planar fixed heating element for heating the fixing belt 27A abuts (contacts) inside the fixing belt 27A to form a fixing belt unit. BU1 is provided. A nip portion N is formed between the first fixing roller 17a and the second fixing roller 17b with the fixing belt 27A interposed therebetween. A recording paper P as a transfer material is provided below the fixing belt 27A.
Are guided to the nip portion N, and a guide plate 173 is provided for receiving the heat of the fixing belt 27A to form a preheating area.

A gear Ga coupled to the belt driving gear Gb is provided integrally with the tension roller 17A, and the belt driving gear G
By the drive rotation of the belt drive motor M1 linked to b,
By rotating the tension roller 17A, the fixing belt 27A is rotated. Further, the fixing belt unit BU1 is rotatably provided about a shaft J1 integrated with the stretching roller 17A, and the rotation of the fixing belt unit BU1 about the shaft J1 as a fulcrum causes the nip portion N side of the fixing belt unit BU1 ( The first fixing roller 17a side) can be opened.

When the recording paper P as a transfer material is jammed (paper jam) in the nip portion N, the fixing belt unit BU1 is opened around the axis J1 and the first fixing roller 17 is released.
a is separated from the second fixing roller 17b, and the jammed recording paper P is removed with the nip portion N opened. This facilitates the jam processing at the nip portion of the transfer material.

FIG. 5 shows another example of the jam processing at the nip portion N. The gear G coupled to the belt driving gear GB is shown in FIG.
A is provided integrally with the first fixing roller 17a, and the first fixing roller 17a is rotated by the driving rotation of the belt driving motor M2 connected to the belt driving gear GB, thereby rotating the fixing belt 27A. In addition, the fixing belt unit BU1 around the shaft J2 integrated with the first fixing roller 17a.
Is rotatably provided, and the rotation of the fixing belt unit BU1 about the axis J2 as a fulcrum causes the fixing belt unit BU1 to rotate.
Of the stretching roller 17A can be opened. When the fixing belt unit BU1 is opened, the rotation of the cam CM provided integrally and coaxially with the shaft J2 causes the shaft J3 integrated with the second fixing roller 17b to be pushed down by the cam surface (no symbol) of the cam CM. The pressing of the pair of first fixing rollers 17a is released. The second fixing roller 17b is the first fixing roller 1
7a, the nip N can be opened.

When the recording paper P as a transfer material is jammed (paper jam) in the nip portion N, the fixing belt unit BU1 is opened around the axis J2, and the second fixing roller 17b is moved to the first position by the operation of the cam CM. The recording paper P that has been jammed is removed with the nip portion N being opened while being separated from the fixing roller 17a. This facilitates the jam processing at the nip portion of the transfer material.

As described above, the temperature rise of the belt member having poor thermal conductivity is accelerated, the warm-up time is shortened,
In addition, the temperature change and unevenness of the temperature of the belt member during continuous printing are eliminated, and good fixing performance with little fixing offset and fixing unevenness at the time of fixing the toner image on the transfer material at the nip portion is obtained. As a result, it is possible to provide a fixing device that has high-speed capability and that can easily perform jam processing at the nip portion of the transfer material.

Further, a local temperature rise and a temperature drop due to the passage of the transfer material are caused in the second fixing roller member and the belt member forming the nip portion, and the offset and the fixing unevenness occur during the fixing. Happens.

For this reason, in the fixing device shown in FIG. 3, the occurrence of offset, fixing unevenness, etc. is prevented by preventing local temperature rise and temperature decrease of the second fixing roller member and the belt member when the transfer material is passed. Will be described with reference to FIGS. FIG. 6 is a view showing a state in which the transfer material passes through a nip portion and a transfer material on the second fixing roller member in order to prevent a local temperature rise and a temperature decrease of the second fixing roller member when the transfer material passes. FIG. 7 is a diagram illustrating a first example of the position of the transfer material in FIG. 6, FIG. 7 is a diagram illustrating a preferred example of the first example of positioning the transfer material of FIG. 6 on the second fixing roller member, and FIG. FIG. 6 is a diagram illustrating a first example of a state in which a transfer material passes through a nip portion and a position of the transfer material on the belt member in order to prevent a local temperature rise and a temperature decrease of the belt member when the transfer material passes. 9 and FIG.
FIG. 10 is a view showing a preferred method of the first example of positioning of the transfer material on the belt member, and FIG. 10 shows a local temperature rise and temperature drop of the second fixing roller member when the transfer material passes. FIG. 9 is a diagram illustrating a second example of a state in which the transfer material passes through the nip portion and a position of the transfer material on the second fixing roller member, for preventing the occurrence of the transfer error.
FIG. 11 is a diagram showing a preferred method of a second example of positioning the transfer material of FIG. 10 on the second fixing roller member.
Reference numeral 2 denotes a second example of the state of the transfer material passing through the nip portion and the position of the transfer material on the belt member for preventing local increase and decrease of the temperature of the belt member when the transfer material passes. FIG. 13 is a diagram showing a preferred method of a second example of positioning the transfer material of FIG. 12 on the second fixing roller member.

First, a first example of prevention of local temperature rise and temperature decrease of the second fixing roller member when a transfer material is passed will be described below.

According to FIG. 6, the nip portion N of the fixing device 700 includes a first fixing roller 17a as an upper first fixing roller member and a first fixing roller 17a with a fixing belt 27A as a belt member interposed therebetween. In opposition to (in pairs)
The second fixing roller 17b is provided as a lower second fixing roller member. In the nip portion N, the recording papers Pa and Pb that pass between the fixing belt 27A and the second fixing roller 17b interpose the first fixing belt 27A.
The fixing belt 27A is sandwiched between the fixing roller 17a and the second fixing roller 17b, and is heated by the fixing belt 27A.
And the recording paper P by the pressure by the second fixing roller 17b.
The toner images on a and Pb are fixed. At this time, the position of the trailing edge of the recording paper Pa passing first on the second fixing roller 17b and the position of the leading edge of the recording paper Pb passing subsequently on the second fixing roller 17b substantially coincide with each other. It is preferable to control the timing at which the recording paper Pa and the recording paper Pb pass through the nip N.

Accordingly, the paper interval (paper interval) between the rear end of the recording paper Pa passing first through the nip portion N and the front end of the recording paper Pb passing subsequently is the second fixing roller member as the second fixing roller member. When the peripheral length of the roller 17b is L (mm), it is an integral multiple of the peripheral length L of the second fixing roller 17b (L × n, where n is a positive integer).

The position on the second fixing roller 17b of the trailing end of the recording paper Pa passing first and the position of the leading end of the recording paper Pb passing on the second fixing roller 17b substantially coincide with each other. A specific preferable method for passing the recording paper Pa and the recording paper Pb through the nip portion N is shown in FIG.
As shown in FIG. 7, the circumferential length of the photosensitive drum 10 as an image forming body is an integer multiple (L in FIG. 7) of the circumferential length (L) of the second fixing roller 17b, and is equally divided into three. The image formation and the feeding of the recording paper P are performed in synchronization with the points P1, P2, and P3 on the photosensitive drum 10, and the positioning on the second fixing roller 17b is performed.

Further, in the above description, the position on the second fixing roller 17b of the trailing end of the recording paper Pa passing first and the position of the leading end of the recording paper Pb passing on the second fixing roller 17b substantially coincide with each other. In order to prevent the transfer material from repeatedly passing through the second fixing roller 17b at the same position,
About 1/10 or less of the circumferential length L of the second fixing roller 17b (L
/ 10 or less) is preferably passed through the position on the second fixing roller 17b in order to prevent temperature fluctuation of the second fixing roller 17b. Accordingly, the timing of image formation and the feeding of the recording paper P described with reference to FIG.
For points P1, P2, and P3 on the photosensitive drum 10,
About 1/10 or less of the circumferential length L of the second fixing roller 17b (L
/ 10 or less) is preferable in order to make the deterioration of the photosensitive drum 10 uniform.

As described above, the deterioration of the image forming body can be made uniform, and the occurrence of offset and fixing unevenness due to local temperature rise and temperature decrease of the second fixing roller member due to the passage of the transfer material can be prevented. Thus, a fixing device capable of obtaining uniform fixing properties can be obtained.

Next, a first example of prevention of local temperature rise and temperature decrease of the belt member when the transfer material is passed will be described below.

Referring to FIG. 8, the nip portion N of the fixing device 700 includes a first fixing roller 17a as an upper first fixing roller member and a first fixing roller 17a with a fixing belt 27A as a belt member interposed therebetween. In opposition to (in pairs)
The second fixing roller 17b is provided as a lower second fixing roller member. In the nip portion N, the recording papers Pa and Pb that pass between the fixing belt 27A and the second fixing roller 17b interpose the first fixing belt 27A.
The fixing belt 27A is sandwiched between the fixing roller 17a and the second fixing roller 17b, and is heated by the fixing belt 27A.
And the recording paper P by the pressure by the second fixing roller 17b.
The toner images on a and Pb are fixed. At this time, the position on the fixing belt 27A of the rear end of the recording paper Pa passing first,
It is preferable to control the timing of passing the recording paper Pa and the recording paper Pb to the nip portion N such that the position of the leading end of the recording paper Pb that subsequently passes on the fixing belt 27A substantially matches.

Therefore, the paper interval (paper interval) between the rear end of the recording paper Pa passing first through the nip portion N and the front end of the recording paper Pb passing therethrough is determined by the fixing belt 27A as a belt member.
Is a multiple of the circumference L1 of the fixing belt 27A (L1 × n1, where n1 is a positive integer).

The position on the fixing belt 27A at the rear end of the recording paper Pa that passes first and the position on the fixing belt 27A at the front end of the recording paper Pb that subsequently passes are substantially the same.
As a specific preferable method for passing the recording paper Pa and the recording paper Pb through the nip portion N, as shown in FIG. 9, the peripheral length of the photosensitive drum 10 as an image forming body is fixed to a fixing belt. An integral multiple of the circumference (L1) of 27A (3 in FIG. 9)
The image forming and the feeding of the recording paper P are performed in synchronization with the points P4, P5, and P6 on the photosensitive drum 10 which are divided into three equal parts.
Perform the above alignment.

Further, in the above, the position on the fixing belt 27A of the trailing end of the recording paper Pa that passes first and the position on the fixing belt 27A of the leading end of the recording paper Pb that passes subsequently need only substantially match. Further, in order to prevent the transfer material from repeatedly passing through the fixing belt 27A at the same position, the fixing belt 2
About 1/10 or less of 7A circumference L1 (L1 / 10 or less)
It is preferable to allow the sheet to pass through the position on the fixing belt 27A with a deviation from the viewpoint of preventing temperature fluctuation of the fixing belt 27A. Accordingly, the timing of the image formation and the feeding of the recording paper P described with reference to FIG. It is preferable to perform the process with a deviation of about 1 L or less (L 1/10 or less) in order to make the deterioration of the photosensitive drum 10 uniform.

In FIG. 8 or FIG. 9, FIG.
Alternatively, the position on the second fixing roller 17b of the rear end of the recording paper Pa passing first and the position of the front end of the recording paper Pb passing on the second fixing roller 17b described in FIG. It is more preferable that the control is performed so as to be substantially the same in order to prevent a local temperature rise and temperature decrease of the fixing belt 27A due to the passage of the recording paper P.
(L1 (mm)) is an integral multiple (L1 = L × n2, n2 is a positive integer) of the circumference (L (mm)) of the second fixing roller 17b, and is used for basic temperature control. In addition, by forcibly heating the heating element unit 170 (see FIG. 3) at the time of paper passing, the heating element unit 170 is lowered by the passage of the recording paper P.
The local temperature decrease of the second fixing roller 17b and the fixing belt 27A is reduced.

As described above, the deterioration of the image forming body can be made uniform, and the occurrence of offset and fixing unevenness due to local rise and fall of the temperature of the belt member due to the passage of the transfer material can be prevented. This makes it possible to provide a fixing device capable of obtaining excellent fixing properties.

Next, a second example of prevention of local temperature rise and temperature decrease of the second fixing roller member when the transfer material is passed will be described below.

As shown in FIG. 10, the nip portion N of the fixing device 700 includes a first fixing roller 17a as an upper first fixing roller member and a first fixing roller 17a with a fixing belt 27A as a belt member interposed therebetween. And a second fixing roller member as a lower second fixing roller member provided so as to face (in pairs with)
It is formed by the fixing roller 17b. Of the nip N
The recording papers Pa and Pb that are passed between the fixing belt 27A and the second fixing roller 17b are sandwiched between the first fixing roller 17a and the second fixing roller 17b with the fixing belt 27A interposed therebetween. Heating and fixing belt 27
The toner images on the recording sheets Pa and Pb are fixed by the pressure A and the second fixing roller 17b. At this time, assuming that the circumferential length of the second fixing roller 17b is L (mm), the position of the leading end of the recording paper Pa passing first on the second fixing roller 17b and the leading end of the recording paper Pb passing subsequently. The position on the second fixing roller 17b is the circumference L of the second fixing roller 17b.
On the other hand, as shown in FIG. 11, L / 3 to 2 × L / 3, preferably, the recording paper Pa and the recording paper Pb are passed through the nip portion N so as to be displaced by about L / 2 for each print. It is preferable to control the timing. Thereby, it is possible to prevent a local decrease in the temperature of the second fixing roller 17b.

Therefore, the distance between the leading end of the recording paper Pa passing first through the nip portion N and the leading end of the recording paper Pb passing subsequently is equal to the distance between the leading end of the second fixing roller 17b as the second fixing roller member. For the length L, ((L × n) + (L / 3 to 2
× L / 3)), preferably ((L × n) + L / 2). Here, n is a positive integer. Further, the distance between the leading end of the leading end of the recording paper Pa passing first on the second fixing roller 17b and the leading end of the subsequently passing recording paper Pb on the second fixing roller 17b is set to ((L × n) + (L /
3 to 2 × L / 3)), preferably ((L × n) + L /
2) In addition, in order to prevent the transfer material from repeatedly passing through the second fixing roller 17b at the same position, the second fixing roller 17
It is preferable to provide a sheet with a deviation of about 1/10 or less (L / 10 or less) of the circumference L of b in order to prevent a local temperature decrease of the second fixing roller 17b.

The position on the second fixing roller 17b of the leading end of the recording paper Pa passing first and the position of the leading end of the recording paper Pb passing on the second fixing roller 17b pass as the second fixing roller member. Is ((L × n) + (L / 3 to 2 × L / 3)), preferably ((L × n) + L / 2), and further L / 10 As a specific preferable method for passing the nip portion N with a deviation of about the same or less, as shown in FIG. 11, the circumferential length of the photosensitive drum 10 as an image forming body is
The photosensitive drum 1 is an integral multiple of the circumference (L) of b (indicated by 3 in FIG. 11), and is equally divided into three for each print.
For points P1, P2, and P3 on 0, ((L × n) +
(L / 3 to 2 × L / 3)) and the second fixing roller 17
In addition to the deviation of about 1/10 or less of the circumferential length L of the second fixing roller 17b, preferably ((L × n) + L / 2), the second fixing roller 17b
(L (L / 2) + (L / 10) in FIG. 11) is provided, and the timing is adjusted to the shifted positions P11, P21 and the like. It is preferable that the image formation and the feeding of the recording paper P are performed, and the alignment on the second fixing roller 17b is performed in accordance with the shift amount.

As described above, the deterioration of the image forming body can be made uniform, and the occurrence of high-temperature offset and uneven fixing due to local rise and fall of the temperature of the second fixing roller member caused by passing of the transfer material can be prevented. As a result, a fixing device capable of obtaining uniform fixing properties can be obtained.

Further, a second example of prevention of local temperature rise and temperature decrease of the belt member when the transfer material is passed will be described below.

As shown in FIG. 12, the nip portion N of the fixing device 700 includes a first fixing roller 17a as an upper first fixing roller member and a first fixing roller 17a with a fixing belt 27A as a belt member interposed therebetween. And a second fixing roller member as a lower second fixing roller member provided opposite to (in pairs with)
It is formed by the fixing roller 17b. Of the nip N
The recording papers Pa and Pb that are passed between the fixing belt 27A and the second fixing roller 17b are sandwiched between the first fixing roller 17a and the second fixing roller 17b with the fixing belt 27A interposed therebetween. Heating and fixing belt 27
The toner images on the recording sheets Pa and Pb are fixed by the pressure A and the second fixing roller 17b. At this time, when the circumferential length of the fixing belt 27A is L1 (mm), the position of the leading end of the recording paper Pa passing first on the fixing belt 27A is:
The position of the leading end of the recording paper Pb passing therethrough on the fixing belt 27A corresponds to L1 of the circumference L1 of the fixing belt 27A.
/ 3 to 2 × L1 / 3, preferably as shown in FIG.
The recording paper P is displaced by about L1 / 2 for each print.
It is preferable to control the timing at which a and the recording paper Pb pass through the nip N. Thereby, the fixing belt 27A
Can prevent a local temperature decrease.

Accordingly, the distance between the leading end of the recording paper Pa passing first through the nip portion N and the leading end of the recording paper Pb passing subsequently is smaller than the circumferential length L1 of the fixing belt 27A as a belt member. ((L1 × n1) + (L1 / 3 to 2 × L
1/3)), preferably ((L1 × n1) + L1 / 2)
And Here, n1 is a positive integer. Further, the position on the fixing belt 27A at the leading end of the recording paper Pa passing first and the fixing belt 27 at the leading end of the recording paper Pb passing subsequently.
The distance between the tip and the position on A is ((L1 × n1) + (L1
/ 3 to 2 × L1 / 3)), preferably ((L1 × n1)
+ L1 / 2), in order to prevent the transfer material from repeatedly passing through the fixing belt 27A at the same position.
It is preferable to provide a sheet with a deviation of about 1/10 or less (L1 / 10 or less) of the circumference L1 of A in order to prevent a local temperature decrease of the fixing belt 27A.

The position of the leading end of the recording paper Pa passing first on the fixing belt 27A and the position of the leading end of the recording paper Pb passing on the fixing belt 27A are determined by the circumferential length of the fixing belt 27A as a belt member. For L1, ((L1 × n1)
+ (L1 / 3 to 2L1 / 3)), preferably ((L1 ×
n1) + L1 / 2), and a specific preferable method of passing the nip N with a deviation of about L1 / 10 or less is as shown in FIG. The circumferential length of the drum 10 is set to an integral multiple of the circumferential length (L1) of the fixing belt 27A (in FIG. 13, indicated by three times), and points P4 and P4 on the photosensitive drum 10 are equally divided for each print. For P5 and P6, ((L1 × n1) +
(L1 / 3 to 2L1 / 3)) and fixing belt 27A
(L1 × n1) + L1 / 2, and the fixing belt 27
A shift of about 1/10 or less of the circumference L1 of A (shown as ((L1 / 2) + (L1 / 10)) in FIG. 13) is provided, and the timing is adjusted to the shifted positions P41, P51 and the like. It is preferable to perform image formation and feed of the recording paper P, and to perform position adjustment on the fixing belt 27A corresponding to the above-mentioned shift amount.

In FIG. 12 or FIG. 13, the position of the leading end of the recording paper Pa passing first on the second fixing roller 17b and the position of the recording paper Pb passing subsequently, as described in FIG. 10 or FIG. The position of the leading end on the second fixing roller 17b is １ ／ of the circumference of the second fixing roller 17b.
It can be controlled that the recording paper P is displaced by about 2/3.
It is more preferable to prevent the local temperature rise and temperature decrease of the fixing belt 27A due to the paper passing through the second fixing roller 17A, and to further reduce the circumferential length (L1 (mm)) of the fixing belt 27A.
Integer multiple (L1 = L × n2, n) of the circumference (L (mm)) of b
2 is a positive integer). In addition to the basic temperature control, the heating element unit 170 (see FIG. 3) is forcibly heated at the time of paper passing, so that it is lowered by the passage of the recording paper P. Second fixing roller 17b and fixing belt 27A
To reduce the local temperature drop.

As described above, the deterioration of the image forming body can be made uniform, and the occurrence of high-temperature offset and uneven fixing due to local rise and fall of the temperature of the belt member due to the passage of the transfer material can be prevented. A fixing device capable of obtaining uniform fixing properties can be obtained.

[0111]

According to the first or second aspect, the temperature rise of the belt member having poor thermal conductivity is accelerated, the warm-up time is shortened, and the temperature change and the temperature non-uniformity of the belt member during continuous printing are reduced. In the fixing of the toner image on the transfer material at the nip portion, good fixing performance with less fixing offset and fixing unevenness is obtained. A fixing device that can easily perform the jam processing can be provided.

According to the third to ninth aspects, the temperature rise of the belt member having poor thermal conductivity is accelerated, the warm-up time is shortened, and the temperature change and the temperature unevenness of the belt member during continuous printing are eliminated. As a result, when the toner image is fixed on the transfer material at the nip portion, good fixing performance with little fixing offset and fixing unevenness is obtained, high-speed response is achieved, and the second fixing by passing the transfer material is performed. Local temperature rise and temperature decrease of the roller member and belt member are prevented,
It is possible to provide a fixing device that prevents occurrence of offset and fixing unevenness during fixing.

[Brief description of the drawings]

FIG. 1 is a sectional view of a color image forming apparatus showing an embodiment of an image forming apparatus using a fixing device according to the present invention.

FIG. 2 is a side sectional view of the image forming body of FIG. 1;

FIG. 3 is an explanatory diagram of a structure of a fixing device and setting conditions.

FIG. 4 is an explanatory diagram of a first example of a transfer material jam process in a nip portion.

FIG. 5 is an explanatory diagram of a second example of the jam processing of the transfer material in the nip portion.

FIG. 6 illustrates a state in which a transfer material passes through a nip portion and a transfer material on the second fixing roller member in order to prevent a local temperature rise and a temperature decrease of a second fixing roller member when the transfer material passes. It is a figure showing the 1st example with a position.

FIG. 7 is a diagram illustrating a preferred method of a first example of positioning the transfer material of FIG. 6 on a second fixing roller member.

FIG. 8 is a diagram illustrating a first example of a state in which a transfer material passes through a nip portion and a position of the transfer material on the belt member in order to prevent a local temperature rise and a temperature decrease of the belt member when the transfer material passes. It is a figure showing an example.

FIG. 9 is a first example of positioning of the transfer material of FIG. 8 on a belt member;
FIG. 4 is a diagram showing a preferred method of the example of FIG.

FIG. 10 illustrates a state in which the transfer material passes through a nip portion and a transfer material on the second fixing roller member in order to prevent local temperature rise and temperature decrease of the second fixing roller member when the transfer material passes. It is a figure showing the 2nd example with a position.

11 is a diagram showing a preferred method of a second example of positioning the transfer material of FIG. 10 on a second fixing roller member.

FIG. 12 is a diagram illustrating a second example of the state of the transfer material passing through the nip portion and the position of the transfer material on the belt member in order to prevent a local temperature rise and temperature decrease of the belt member when the transfer material passes. It is a figure showing an example.

FIG. 13 is a diagram showing a preferred method of a second example of positioning the transfer material of FIG. 12 on a second fixing roller member.

[Explanation of symbols]

 Reference Signs List 10 photoconductor drum 11 scorotron charger 12 exposure optical system 13 developing device 17A stretching roller 17a first fixing roller 17b second fixing roller 27A fixing belt 170 heating element unit 171 ceramic heater 172 heater holder 173 guide plate 700 fixing device BU1 fixing belt Unit CM Cam GA, Ga Gear GB, Gb Belt drive gear HL1 Halogen lamp N Nip P Recording paper

Claims (9)

[Claims] 1. A fixing belt unit is formed by a first fixing roller member that stretches a belt member on one side, and a roller member that stretches the other side of the belt member together with the first fixing roller member. A second fixing roller member that forms a nip with the first fixing roller member, sandwiching the belt member, and fixes the toner image on the transfer material in the nip portion. A heating means for contacting the belt member from the inside of the belt member and heating the belt member is provided between the first fixing roller member and the roller member, and the belt member is stretched. A fixing device, wherein the fixing belt unit including the heating unit can be opened with the roller member as a fulcrum. 2. A fixing belt unit is formed by a first fixing roller member that stretches a belt member on one side, and a roller member that stretches the other side of the belt member together with the first fixing roller member. A second fixing roller member that forms a nip by pressing the first fixing roller member, forming a pair with the first fixing roller member with the belt member interposed therebetween; A fixing device for fixing the toner image, wherein a heating unit that contacts the belt member from inside the belt member and heats the belt member is provided between the first fixing roller member and the roller member. The first fixing roller member is provided as a fulcrum, and the fixing belt unit including the heating unit is opened with the first fixing roller member as a fulcrum. Fixing apparatus characterized by releasing the pressure on the first fixing roller member. 3. A first fixing roller member that stretches the belt member on one side, a roller member that stretches the other side of the belt member together with the first fixing roller member, and the belt member is sandwiched. A second fixing roller member that forms a nip with the first fixing roller member, and the belt is disposed between the first fixing roller member and the roller member from the inside of the belt member. A fixing device that contacts the member and heats the belt member, wherein the fixing device fixes the toner image on the transfer material in the nip portion; And a position on the second fixing roller member of the end of the transfer material that subsequently passes through the fixing device. 4. A first fixing roller member for stretching a belt member on one side, a roller member for stretching the other side of the belt member together with the first fixing roller member, and sandwiching the belt member. A second fixing roller member that forms a nip with the first fixing roller member, and the belt is disposed between the first fixing roller member and the roller member from the inside of the belt member. A fixing unit for fixing the toner image on the transfer material in the nip portion, wherein a position on the belt member at a rear end of the transfer material that passes first is provided. And a position on the belt member at which the leading end of the transfer material subsequently passes substantially coincides. 5. A position on the second fixing roller member at a rear end of the transfer material that passes first, and a position on the second fixing roller member of a front end of the transfer material that subsequently passes. The fixing device according to claim 4, wherein the values match. 6. A first fixing roller member for stretching a belt member on one side, a roller member for stretching the other side of the belt member together with the first fixing roller member, and sandwiching the belt member. A second fixing roller member that forms a nip with the first fixing roller member, and the belt is disposed between the first fixing roller member and the roller member from the inside of the belt member. A fixing device that contacts the member and heats the belt member, wherein the fixing device fixes the toner image on the transfer material at the nip portion; A position and a position on the second fixing roller member of a leading end of the transfer material that subsequently passes are displaced by ３ to ／ of a circumferential length of the second fixing roller member. Fixing device. 7. A first fixing roller member that stretches the belt member on one side, a roller member that stretches the other side of the belt member together with the first fixing roller member, and the belt member is sandwiched. A second fixing roller member that forms a nip with the first fixing roller member, and the belt is disposed between the first fixing roller member and the roller member from the inside of the belt member. A fixing unit that abuts on the member and heats the belt member; and a fixing device that fixes the toner image on the transfer material in the nip portion. The position of the leading end of the transfer material that subsequently passes on the belt member is １ ／ to ／ of the circumference of the belt member.
A fixing device characterized by being displaced by three. 8. The fixing device according to claim 6, wherein the displacement is performed while avoiding repetition at the same position. 9. A position on the second fixing roller member at a leading end of the transfer material passing first and a position on the second fixing roller member at a leading end of the transfer material passing subsequently. 9. The fixing device according to claim 6, wherein the fixing device is displaced by ３ to ／ of a circumference of the fixing roller member. 9.