JP2000019873A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the end of a light transmissive base substance from being broken by applied pressure and the light transmissive base material from being broken at the time of driving by providing an elastic layer and a heat ray absorbing layer on the outside of the light transmissive base material so that a roll type rotating member for heat ray fixing may be formed and providing flange members having a rotary shaft at both ends thereof. SOLUTION: A heat ray fixing roller 17a is constituted as a soft roller which is provided with the cylindrical light transmissive base substance 171a, and the elastic layer 171d and the heat ray absorbing layer 171b and a mold-releasing layer 171c on the outside of the base substance 171a in this order, and inside which a heat ray irradiating member 171g is arranged. The heat ray emitted from the member 171g is absorbed by the layer 171b, so that the roll type rotating member for thermal fixing capable of instantaneous heating is formed. The cylindrical flange 910 made of a metallic member and having about 1 to 3 mm thickness is fit to the end of the outer peripheral surface of the base material 171a and attached by an adhesive or the like. Since the flange 910 is provided on the outside even when the thermal expansion of the flange 910 is large, the base material 171a is not broken by the thermal expansion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used for an image forming apparatus such as a copying machine, a printer, a facsimile, etc., and more particularly to a fixing device for quick start fixing capable of instantaneous heating.

[0002]

2. Description of the Related Art Conventionally, as a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., a heat roller fixing method has been used as a fixing device having high technical perfection and stability. Machine to full-color machine,
Has been widely adopted.

However, in the conventional heat roller fixing type fixing device, it is necessary to heat the fixing roller having a large heat capacity when heating the transfer material or the toner, so that the energy saving effect is poor and the energy saving is disadvantageous. Further, there is a problem that it takes time to warm up the fixing device during printing, and the printing time (warming up time) becomes longer.

In order to solve this, a film (heat fixing film) is used, the heat roller is brought to the ultimate thickness of the heat fixing film to reduce the heat capacity, and a temperature-controlled heater (ceramic heater) is directly applied to the heat fixing film. A film fixing type fixing device and an image forming device using the same have been proposed, which greatly improve the heat conduction efficiency by being brought into contact with the pressure and achieve energy saving and a quick start which requires almost no warm-up time. Have been

Further, as a modification of the heat roller, a transparent substrate is used as a fixing roller, and the toner is heated and fixed by irradiating a toner with a heat ray from a halogen lamp provided therein, thereby achieving a quick start without a warm-up time. The fixing method is described in JP-A-52-106741 and JP-A-57-82.
Nos. 240, 57-102736 and 57-
No. 102741 discloses this. Further, a light absorbing layer is provided on the outer peripheral surface of the light-transmitting substrate to form a fixing roller (rotating member for heat ray fixing), and light from a halogen lamp provided inside the cylindrical light-transmitting substrate is transmitted. JP-A-59-65867 discloses a fixing method in which light is absorbed by a light absorbing layer provided on the outer peripheral surface of a substrate and a toner image is fixed by heat of the light absorbing layer.

[0006]

However, a method of irradiating a heat ray of a halogen lamp through a light-transmitting substrate to heat and fix a toner disclosed in Japanese Patent Application Laid-Open No. 52-106741 or the like is disclosed in Japanese Patent Application Laid-Open No. No. 6,658,673 discloses a method of irradiating a light absorbing layer with a heat ray of a halogen lamp to a light absorbing layer through a light-transmitting substrate and fixing the toner by the heat of the light absorbing layer. However, since a cylindrical glass member is mainly used as a material of the light-transmitting substrate, the end of the light-transmitting substrate of the rotating member for hot-wire fixing is pressed by the pressure applied to the rotating member for hot-wire fixing. The problem of being damaged occurs. Therefore, it is difficult to drive the heat ray fixing rotating member from the end of the light transmitting substrate, and if the driving is performed from the end of the light transmitting substrate, the light transmitting substrate is damaged when the heat ray fixing rotating member is driven. There is also the problem of being done. There is also a problem that it is difficult to find the center position of the translucent substrate.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, prevents breakage of the end of a light-transmitting substrate due to pressure applied to a rotary member for fixing heat rays, and prevents light from being transmitted when rotating the rotary member for fixing heat rays. An object of the present invention is to provide a fixing device that prevents breakage of a base.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device for fixing a toner image on a transfer material to the transfer material by heating and pressurizing. A light-transmissive substrate, and an elastic layer and a heat-absorbing layer provided on the outside of the light-transmissive substrate to form a roll-shaped rotating member for fixing a heat ray, and the flange member having a rotating shaft is formed of the transparent member. This is achieved by a fixing device characterized by being provided at both ends of a base (first invention).

Another object of the present invention is to provide a fixing device for fixing a toner image on a transfer material to the transfer material by heating and pressurizing, wherein a heat ray irradiating means for emitting heat rays is disposed inside the cylindrical light transmitting means. A base and an elastic layer and a heat ray absorbing layer are provided outside the light-transmitting base to form a roll-shaped rotating member for fixing heat rays, and a wide ring member is provided at an end of the light-transmitting base. According to a second aspect of the present invention, there is provided a fixing device, wherein a bearing member of the heat ray fixing rotating member is provided via the ring member.

Another object of the present invention is to provide a fixing device for fixing a toner image on a transfer material to the transfer material by heating and pressurizing, wherein a cylindrical heat-transmissive means for internally radiating a heat ray is provided. A substrate and an elastic layer and a heat ray absorbing layer are provided on the outside of the light-transmitting substrate to form a roll-shaped heat ray fixing rotating member, and the fixing rotating member is opposed to the heat ray fixing rotating member. A third aspect of the present invention is achieved by a fixing device, wherein the fixing rotary member is driven to rotate, and the heat ray fixing rotary member is driven to rotate.

[0011]

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. In the following description of the embodiment, in the transfer area, the surface (upper surface) of the transfer material on the side facing the image forming body is the front surface, and the other surface of the transfer material, that is, the transfer material on the side facing the intermediate transfer body. The surface (lower surface) is called a back surface, an image transferred to the front surface of the transfer material is called a front image, and an image transferred to the back surface of the transfer material is called a back image.

An image forming process and each mechanism of an embodiment of a fixing device and an image forming apparatus using the same according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a color image forming apparatus showing an embodiment of a fixing device according to the present invention and an image forming apparatus using the same. FIG. 2 shows a toner image forming state in the image forming apparatus of FIG. FIG. 2A is a diagram illustrating a toner image formation state when a back surface image formed on an image forming body is transferred onto an intermediate transfer body, and FIG. 2B is a diagram illustrating an intermediate transfer body. FIG. 2 is a diagram showing a toner image forming state when a front image is formed on an image forming body in synchronization with an upper back image.
(C) is a diagram showing double-sided image formation on a transfer material,
FIG. 3 is a diagram showing an example of a document image reading unit.
5 is a control circuit block diagram of the image forming apparatus, and FIG.
FIG. 6 is an explanatory view showing the structure of the fixing device, FIG. 6 is an enlarged sectional configuration view of a roll-shaped heat ray fixing rotating member, and FIG. FIG. 8 is a diagram showing a concentration distribution, and FIG. 8 is a diagram showing an outer diameter and a thickness of a light-transmitting substrate of a roll-shaped rotating member for fixing a heat ray.

As shown in FIGS. 3 and 4, a document image reading device 500 as a document image reading means includes a reading device main body 501, a document storage plate 505 for storing a document PS, a document sending roller 502, a transparent plate 503. , Document feed roller 504, document discharge tray 506, and transparent plate 503
And a line-shaped document image reading sensor PS1 and PS2 for reading a document image of the document PS from above and below. The control unit is connected to a signal line incorporated in an external device or a color image forming apparatus described below. Connected.

When the original PS sent by the original sending roller 502 passes through the transparent plate 503, the original PS is converted to a one-sided original by original image reading sensors PS1 and PS2 provided above and below the transparent plate 503. Determination of whether the document is a double-sided document (single-sided or double-sided) and reading of image data of the document PS are performed.

In this embodiment, one-sided / two-sided discrimination and image data reading are performed by one set of upper and lower sensors. However, a plurality of sensors respectively corresponding to image data reading and one-sided / two-sided discrimination may be provided. For example, image data may be read after a single-sided or double-sided discrimination has been performed using a plurality of sensors respectively corresponding to each other. Original image reading sensor PS1
Alternatively, image data of one bundle of originals PS is read by PS2 and stored in the RAM through the control unit.

When the image is determined to be a double-sided image,
The image data of the original PS is read by the original image reading means shown in FIG. 3, and the double-sided image forming program P1 stored in the ROM shown in FIG. P1 is executed, and the image forming process is performed.

1 and 2, reference numeral 10 denotes a photosensitive drum as an image forming body, 11 denotes a scorotron charger as a charging unit for each color, and 12 denotes an exposure optical system as an image writing unit for each color. , 13 are developing devices as developing means for each color, 14
a is an intermediate transfer belt that is an intermediate transfer member, 14c is a transfer device that is a first and a second transfer unit, 14g is a back surface transfer device that is a third transfer unit, 14m is a charge remover that is a charge removing unit,
Reference numeral 150 denotes a paper charger serving as a transfer material charging unit, 14h denotes a paper separation AC static eliminator serving as a transfer material separating unit, 160 denotes a conveyance unit having a separation claw 210 serving as a claw member and a spur 162 serving as a spur member, and 169 denotes a spur member. An entry guide plate 17 as an entry guide member is the fixing device of the first example.

The photosensitive drum 10, which is an image forming body, has a transparent conductive layer, a, on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin.
A photosensitive layer (also referred to as a photoconductive layer) such as an Si layer or an organic photosensitive layer (OPC), which is rotated clockwise as indicated by an arrow in FIG. 1 with the conductive layer grounded.

A scorotron charger 11, which is a charging unit for each color, an exposure optical system 12, which is an image writing unit for each color, and a developing unit 13, which is a developing unit for each color, form a set of yellow (Y) ), Magenta (M), cyan (C), and black (K) are provided for the image forming process, and four sets are provided.
With respect to the rotation direction of 0, they are arranged in the order of Y, M, C, K.

The scorotron charger 11, which is a charging means for each color, has a control grid maintained at a predetermined potential and a discharge electrode 11a composed of, for example, a sawtooth electrode, and faces the photosensitive layer of the photosensitive drum 10. And installed
The charging operation (minus charging in the present embodiment) is performed by corona discharge having the same polarity as the toner, and the photosensitive drum 1 is charged.
A uniform potential is given to 0. As the discharge electrode 11a, a wire electrode or a needle electrode may be used.

Exposure optical system 1 as image writing means for each color
2 indicates that the exposure position on the photosensitive drum 10 is the photosensitive drum 1 with respect to the scorotron charger 11 for each color described above.
It is arranged inside the photoconductor drum 10 so as to be located on the downstream side in the rotation direction of 0. Each exposure optical system 12
Is a linear exposure element 12a in which a plurality of LEDs (light emitting diodes) as light emitting elements of image exposure light arranged in the main scanning direction are arranged in parallel with the drum axis, and a light focusing element as an imaging element. Exposure unit composed of an optical transmission body (trade name: Selfoc lens array) 12b and a lens holder (not shown), which is attached to the holding member 20. In addition to the exposure optical system 12 for each color, the transfer simultaneous exposure unit 12d and the uniform exposure unit 12e are attached to the holding member 20, and are housed integrally inside the light-transmitting substrate of the photosensitive drum 10. The exposure optical system 12 for each color performs image exposure of the photosensitive layer of the photosensitive drum 10 from the back surface in accordance with image data of each color read by a separate image reading device and stored in the memory, and electrostatically exposes the photosensitive drum 10 to the photosensitive layer. Form a latent image. As the exposure element 12a, besides LED, FL (phosphor emission), EL (electroluminescence), PL
It is also possible to use a plurality of light emitting elements such as (plasma discharge) arranged in an array. The emission wavelength of the image exposure light emitting element usually ranges from 780 to 900 nm, which is highly transparent to the Y, M, and C toners.
In the present embodiment, since the image exposure is performed from the back surface, a shorter wavelength of 400 to 780 nm, which does not have sufficient transparency to the color toner, may be used. Most of the image exposure light is absorbed by the photosensitive layer.

The developing device 13 as a developing means for each color keeps a predetermined gap with respect to the peripheral surface of the photosensitive drum 10 and rotates in a forward direction with respect to the rotating direction of the photosensitive drum 10, for example, 0.5 to 1 mm in thickness. And a developing casing 131 formed of a cylindrical nonmagnetic stainless steel or aluminum material having an outer diameter of 15 to 25 mm, and a developing casing 138. Inside the developing casing 138, yellow (Y) and magenta ( M), cyan (C) and black (K) one-component or two-component developers. Each developing unit 13
Is maintained in a non-contact state with a predetermined gap, for example, 100 to 500 μm, from the photosensitive drum 10 by an abutting roller (not shown), and applies a developing bias in which a DC voltage and an AC voltage are superimposed on the developing sleeve 131. By doing
Non-contact reversal development is performed to form a toner image on the photosensitive drum 10.

The intermediate transfer belt 14a as an intermediate transfer member has a volume resistivity of ¹⁰ 10 Ω · cm to 10 ¹⁶ Ω · cm, preferably ¹⁰ 10 Ω · cm.
^12-10 is an endless belt ¹⁵ Omega · cm, for example modified polyimide, thermal curing polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, nylon alloys such as engineering plastic thickness was dispersed with a conductive material of 0.1 This is a seamless belt having a two-layer structure in which a fluorine coating having a thickness of 5 to 50 μm is preferably formed on the outside of a semiconductive film substrate having a thickness of 1.0 to 1.0 mm, preferably as a toner filming preventing layer. As the base of the belt,
In addition, a semiconductive rubber belt having a thickness of 0.5 to 2.0 mm in which a conductive material is dispersed in silicon rubber or urethane rubber can be used. Intermediate transfer belt 14a
Are stretched in contact with a driving roller 14d, a ground roller 14j, a driven roller 14e, and a tension roller 14i, which are roller members, respectively, and are rotated in a counterclockwise direction indicated by an arrow in FIG. Driven roller 14e, ground roller 1
4j and the drive roller 14d are fixedly rotated, and the tension roller 14i is movably supported and rotated by the elastic force of a spring or the like (not shown). The drive roller 14d is rotated by a drive motor (not shown), and drives and rotates the intermediate transfer belt 14a. Intermediate transfer belt 14
a of the ground roller 14j and the driven roller 14e
And the tension roller 14i is driven to rotate. The slack of the rotating intermediate transfer belt 14a is tensioned by the tension roller 14i. Intermediate transfer belt 14a
The recording paper P as a transfer material is supplied to a position where the recording paper P is stretched over the driven roller 14e, and the recording paper P is conveyed by the intermediate transfer belt 14a. Curvature portion KT at the end on the fixing device 17 side of intermediate transfer belt 14a stretched around drive roller 14d
At this time, the recording paper P is separated from the intermediate transfer belt 14a.

Transfer device 14 as first and second transfer means
c denotes the photosensitive drum 10 with the intermediate transfer belt 14a interposed therebetween.
A transfer area 14b is formed between the intermediate transfer belt 14a and the photosensitive drum 10. A DC voltage having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied to the transfer device 14c, and the toner image on the photosensitive drum 10 is transferred onto the intermediate transfer belt 14a or onto the surface of the recording paper P as a transfer material. Transcribe.

The back transfer unit 14g, which is a third transfer means, is preferably constituted by a corona discharger, and is a conductive ground roller 14 grounded with the intermediate transfer belt 14a interposed therebetween.
j, a DC voltage having a polarity opposite to that of the toner (positive polarity in this embodiment) is applied, and the toner image on the intermediate transfer belt 14a is transferred to the back surface of the recording paper P.

The static eliminator 14m, which is a static eliminator, is preferably constituted by a corona discharger, and is disposed downstream of the transfer unit 14c, which is the first and second transfer unit, in the moving direction of the intermediate transfer belt 14a. 14c is provided in parallel with
An AC voltage on which a DC voltage having the same polarity or opposite polarity to the toner is superimposed is applied, and the charge of the intermediate transfer belt 14a charged by the voltage application of the transfer device 14c is eliminated.

The paper charger 150, which is a transfer material charging means, is preferably constituted by a corona discharger, and is provided to face the driven roller 14e with the intermediate transfer belt 14a interposed therebetween.
Same polarity as toner (minus polarity in this embodiment)
Is applied, and the recording paper P is charged and attracted to the intermediate transfer belt 14a. In addition to the corona discharger, a paper charging brush or a paper charging roller that can abut and release the intermediate transfer belt 14a can be used as the paper charger 150.

Paper separation AC neutralizer 1 as transfer material separating means
4h is preferably formed of a corona discharger, and is provided at an end of the intermediate transfer belt 14a on the side of the fixing device 17 as needed, facing the conductive drive roller 14d grounded with the intermediate transfer belt 14a interposed therebetween. If necessary, an AC voltage in which a DC voltage having the same polarity or opposite polarity to the toner is superimposed is applied, and the recording paper P conveyed by the intermediate transfer belt 14a is discharged and separated from the intermediate transfer belt 14a.

The transport section 160 includes a separation claw 210 as a claw member.
And a spur 162 serving as a spur member. The transport unit 160 includes the fixing device 1
7, the intermediate transfer belt 14a is deformed, the toner image carried on the intermediate transfer belt 14a tends to be fused, and the transfer becomes difficult.
4a is prevented from sticking to the toner.

The separation claw 210, which is a claw member, approaches the curvature portion KT of the intermediate transfer belt 14a, and
Is fixed to the support shaft 221 at a predetermined interval, preferably 0.1 to 2.0 mm, and when the recording paper P is separated from the intermediate transfer belt 14a, the intermediate transfer belt 14
The leading end of the recording paper P that is to be bent and conveyed in the direction a is brought into contact with the recording paper P to assist the separation of the recording paper P.

The spur 162, which is a spur member, has a plurality of protrusions 162a on its peripheral surface, and is provided rotatably about a rotation support shaft 165. The spur 162 guides the back side of the recording sheet P to convey the recording sheet P, prevents the back side toner image of the recording sheet P having the toner image on both sides from being disturbed, and also fixes the recording sheet P to the fixing device 17. The recording paper P is stably conveyed to the fixing device 17 while keeping the entering direction constant.

The separation claw 210 and the spur 162 are connected to the curvature portion KT of the intermediate transfer belt 14a and the nip portion T of the fixing device 17.
The surface of the photoconductor drum 1 with respect to a surface PL1 (hereinafter, referred to as a transfer material transport surface PL1) connecting an entrance portion (entrance portion) of the transfer material to the photoconductor drum 1
On the other side of the transfer material transfer surface PL1, the transfer material transfer surface PL1 is in contact with or close to the transfer material transfer surface PL1. It is also possible to provide spurs 162 as spur members on both sides of the transfer material transport surface PL1.

An entry guide plate 169 serving as an entry guide member
Is disposed in contact with or close to the transfer material transport surface PL1 on the opposite side of the photosensitive drum 10, and the leading end guides the recording paper P so that the leading end of the recording paper P is prevented from wrinkling during fixing. The fixing device 17 is caused to enter the nip portion T.

The fixing device 17 has a front surface image (an upper surface side image).
A heat-fixing roller 17a as a roll-shaped hot-wire fixing rotary member having elasticity on the upper side (front side) for fixing the toner image on the lower side, and a lower side for fixing the toner image on the back side image (image on the lower side). And a metal roller 47a as a rigid roll-shaped fixing rotating member on the side (rear side).
7a, the recording paper P is sandwiched by a nip portion T formed between the recording paper P and the toner image on the recording paper P is fixed by applying heat and pressure. Inside the heat ray fixing roller 17a, a heat ray irradiation member 171g as a heat ray irradiation unit is provided.

Next, the image forming process will be described.

The photosensitive drum 10 is rotated clockwise as indicated by an arrow in FIG. 1 by starting a photosensitive member driving motor (not shown) at the start of image recording, and is simultaneously exposed to light by the charging action of a yellow (Y) scorotron charger 11. Body drum 1
Application of a potential to 0 starts.

After the photosensitive drum 10 is applied with a potential, the Y exposure optical system 12 starts image writing with a first color signal, that is, an electric signal corresponding to the Y image data. An electrostatic latent image corresponding to the Y image of the original image is formed on the front surface.

The latent image is reversal-developed in a non-contact state by the Y developing unit 13, and a yellow (Y) toner image is formed on the photosensitive drum 10.

Next, a potential is applied to the photosensitive drum 10 from above the Y toner image by the charging action of the magenta (M) scorotron charger 11, and the second color signal, that is, the M color signal, is applied by the M exposure optical system 12. Image writing is performed by an electric signal corresponding to the image data, and the magenta (M) toner image is superimposed on the yellow (Y) toner image by non-contact reversal development by the M developing unit 13. It is formed.

By the same process, the cyan (C) toner image corresponding to the third color signal is further superimposed by the cyan (C) scorotron charger 11, the exposure optical system 12 of C and the developing device 13 of C. The black (K) toner image corresponding to the fourth color signal is sequentially superimposed thereon by a black (K) scorotron charger 11, a K exposure optical system 12, and a K developing device 13. A superposed color toner image of four colors of yellow (Y), magenta (M), cyan (C) and black (K) is formed on the peripheral surface within one rotation of the photosensitive drum 10. (Toner image forming means).

These Y, M, C and K exposure optical systems 12
Image writing on the photosensitive layer of the photosensitive drum 10 is performed from the inside of the drum through the above-described translucent substrate. Therefore, the writing of the images corresponding to the second, third and fourth color signals is performed without any influence from the previously formed toner image, and is equivalent to the image corresponding to the first color signal. Can be formed.

In the transfer area 14b, the superimposed color toner image serving as the back surface image formed on the photosensitive drum 10 as the image forming body by the above-described image forming process is formed.
By the transfer device 14c as a first transfer unit, the transfer (1) is collectively performed on the intermediate transfer belt 14a as the
The next transfer is performed (FIG. 2A). At this time, uniform exposure may be performed by the simultaneous transfer exposure device 12d provided inside the photosensitive drum 10 so that good transfer is performed.

The toner remaining on the peripheral surface of the photoconductive drum 10 after the transfer is subjected to static elimination by the photoconductive drum AC static eliminator 16, and then enters a cleaning device 19 as image forming body cleaning means. The toner is cleaned by a cleaning blade 19a made of a rubber material in contact with the toner, and collected by a screw 19b in a toner discharge container (not shown). Further, the peripheral surface of the photosensitive drum 10
For example, a uniform exposure device 12 before charging using a light emitting diode
The history of the photosensitive drum 10 in the previous image formation is eliminated by the exposure by e.

The charge on the intermediate transfer belt 14a charged by the transfer unit 14c is removed by a charge removal unit 14m which is a charge removal unit provided in parallel with the transfer unit 14c.

After the superimposed color toner image (second toner image) serving as the back surface image is formed on the intermediate transfer belt 14a as described above, the above-described color image forming process is performed on the photosensitive drum 10. Similarly, a superimposed color toner image (first toner image) to be a surface image continuously
Is formed (FIG. 2B). At this time, the photosensitive drum 1
The image data is changed so that the front side image formed on 0 is a mirror image of the back side image formed on the photosensitive drum 10.

With the formation of a surface image on the photosensitive drum 10, 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 15a, and is used as a transfer material feeding means. Timing roller 1
5b, and driven by the timing roller 15b, the first toner image formed on the photosensitive drum 10 is a surface toner color toner image and the intermediate transfer belt 14
The sheet is fed to the transfer area 14b in synchronization with the color toner image of the back side image, which is the second toner image carried on the transfer area 14b. At this time, the fed recording paper P is charged to the same polarity as the toner by a paper charger 150 which is a transfer material charging means provided on the surface side of the recording paper P, and the intermediate transfer belt 14a
And is fed to the transfer area 14b. By charging the paper with the same polarity as the toner, the toner image is prevented from being attracted to the toner image on the intermediate transfer belt 14a or the toner image on the photoconductor drum 10, thereby preventing the toner image from being disturbed.

In the transfer area 14b, a second voltage to which a voltage having a polarity opposite to that of the toner (positive polarity in this embodiment) is applied.
The surface image on the photosensitive drum 10 is collectively transferred onto the surface of the recording paper P by the transfer device 14c as the transfer means (2).
Next transfer). At this time, the back side image on the intermediate transfer belt 14a is not transferred to the recording paper P and the intermediate transfer belt 1
4a. Transfer device 14 as second transfer means
In the case of secondary transfer by c, so that good transfer is performed,
The uniform exposure may be performed by a simultaneous transfer exposure device 12d using, for example, a light emitting diode, provided inside the photosensitive drum 10 so as to face the transfer area 14b. Further, the intermediate transfer belt 14a charged by the transfer device 14c
Is removed by the charge remover 14m.

The recording paper P on which the color toner image has been transferred to the front surface is conveyed to a back transfer device 14g as a third transfer means to which a voltage having a polarity opposite to that of the toner (positive polarity in this embodiment) is applied. Then, the back side image on the peripheral surface of the intermediate transfer belt 14a is collectively transferred (tertiary transfer) to the back side of the recording paper P by the back side transfer unit 14g (FIG. 2C).

The recording paper P on which the color toner images are formed on both sides is formed by the curvature of the curvature portion KT of the intermediate transfer belt 14a and the paper as transfer material separating means provided at the end of the intermediate transfer belt 14a as necessary. The spur 162 provided on the transport unit 160 is separated from the intermediate transfer belt 14a by the static elimination action of the separation AC neutralizer 14h and the separation claw 210 provided on the transport unit 160 at a predetermined interval from the intermediate transfer belt 14a. Then, the toner is stably conveyed to the fixing device 17 through the entry guide plate 169, and the leading end portion is sent to the nip portion T of the fixing device 17 by the entry guide plate 169 to fix the toner image of the surface image (upper image). A heat-fixing roller 17a disposed on the upper side; and a metal roller 47a disposed on the lower side for fixing a toner image of a back image (lower image). The toner image on the recording sheet P is fixed by being added to the heat and pressure at the nip portion T between.
The recording paper P on which double-sided image recording has been performed is sent upside down, and is discharged by a discharge roller 18 to a tray outside the apparatus. Further, as shown by the dashed line in FIG.
A switching member (not shown) may be provided at the outlet of the apparatus, and the sheet may be discharged to a tray outside the apparatus without turning over.

The toner remaining on the peripheral surface of the intermediate transfer belt 14a after the transfer is provided opposite to the driven roller 14e with the intermediate transfer belt 14a interposed therebetween, and is applied to the intermediate transfer belt 14a with the support shaft 142 as a rotation fulcrum. The intermediate transfer member is cleaned by an intermediate transfer member cleaning device 140 which is an intermediate transfer member cleaning unit having an intermediate transfer member cleaning blade 141 capable of contacting and releasing contact.

The toner remaining on the peripheral surface of the photoreceptor drum 10 after the transfer is removed by a photoreceptor drum AC static eliminator 16 and then cleaned by a cleaning device 19. By 12e, the history of the photosensitive drum 10 in the previous image formation is eliminated, and the next image formation cycle is started.

Since the superimposed color toner images are collectively transferred by using the above-described method, color shift of the color image on the intermediate transfer belt 14a, scattering or rubbing of the toner, and the like are less likely to occur, and the image deterioration is small. Double-sided color image formation is performed.

In the original image reading apparatus 500,
When the image data of the document PS read by the document image reading unit shown in FIG. RO shown in FIG.
A single-sided image forming program P2 of the front surface by the photosensitive drum 10 as an image forming body stored in M is read into the RAM through the control unit, and the single-sided image forming program P2 of the front surface is executed by the control unit. The described image forming process of only the surface by the photosensitive drum 10 is continuously performed.

When the image data is determined to be a single-sided image or a double-sided image, the image data of the original PS read by the original image reading means shown in FIG. In the case of copying as an image, a single-sided image forming program P3 on the back surface of the intermediate transfer belt 14a as an intermediate transfer member stored in the ROM shown in FIG. The image forming program P3 is executed, and the image forming process for only the back surface by the intermediate transfer belt 14a described in FIG. 1 is continuously performed.

Although the embodiment of the image forming apparatus using the fixing device of the present invention has been described with reference to color image formation,
The present invention is not necessarily limited to this, and can be applied to monochrome single-sided or double-sided image formation by a process similar to that described with reference to FIGS.
Further, although the embodiment of the image forming apparatus using the fixing device of the present invention has been described with reference to the double-sided image forming apparatus, the fixing device of the present invention is not necessarily limited thereto, and may be applied to an image forming apparatus having only one side. Applicable. Further, although the fixing device described below is also described for double-sided fixing,
The present invention is not limited to this, and may be used as a one-side fixing device.

As shown in FIG. 5, a fixing device 17 is a heat ray as a heat ray fixing rotating member in the form of a roll having an upper (front side) elasticity for fixing a toner image of a front side image (upper side image). A fixing roller 17a and a metal roller 4 serving as a lower (rear side) rigid roll-shaped fixing rotating member for fixing a toner image of a rear side image (lower side image)
7a, and the heat ray fixing roller 1 having elasticity
The recording paper P is sandwiched by a nip portion T having a width of about 2 to 10 mm formed between the recording paper P and the rigid metal roller 47a, and heat and pressure are applied to fix the toner image on the recording paper P. . A heat-fixing roller 17a serving as a roll-shaped rotating member for hot-wire fixing provided on the upper side has a fixing separation claw TR6, a fixing oil cleaning blade TR1, an oil-applied felt in a rotational direction of the hot-wire fixing roller 17a from a position of the nip portion T. TR2 and an oil amount regulating blade TR3 are provided, and a capillary pipe TR5 is supplied from an oil tank TR4.
The oil supplied to the oil-applied felt TR2 is passed through the heat-ray fixing roller 17 by the oil-applied felt TR2.
a. Fixing oil cleaning blade TR
1 cleans the oil on the peripheral surface of the heat ray fixing roller 17a. Therefore, the heat ray fixing roller 17 described later
The temperature sensor TS1 for measuring the temperature of the fixing oil cleaning blade TR1 and the oil application felt TR2
Is provided on the peripheral surface of the heat ray fixing roller 17a that has been cleaned. The transfer material after fixing is separated by the fixing separation claw TR6.

A heat ray fixing roller 17a as a heat ray fixing rotating member for fixing a toner image of a front surface image has a cylindrical light transmitting substrate 171a and an elastic (outer peripheral surface) on the outside (outer peripheral surface) of the light transmitting substrate 171a. A layer 171d, a heat ray absorbing layer 171b, and a release layer 171c are provided in this order, and a light-transmitting substrate 171a is provided.
It is configured as a soft roller in which 171 g of a heat ray irradiation member as a heat ray irradiation means using, for example, a halogen lamp or a xenon lamp is arranged. The heat ray fixing roller 17a as a heat ray fixing rotating member is configured as a highly elastic soft roller as described later. Heat ray irradiation member 1
A heat ray emitted from 71 g is absorbed by the heat ray absorbing layer 171b, and a roll-shaped heat ray fixing rotating member capable of instantaneous heating is formed.

Further, the metal roller 47a as a fixing rotating member for fixing the toner image of the back side image is formed by baking or applying a Teflon coat to the outer peripheral surface, for example, an iron material, a steel material, etc. (0.15-0.
76) It is formed of a cylindrical metal pipe 470 using × 10 ⁻³ J / cm · s · K), and is configured as a hard roller in which a halogen heater 471c is disposed inside the metal pipe 470.

A nip portion T having a convex upper side is formed between the upper soft roller and the lower hard roller, and the toner image is fixed.

TS1 is a temperature sensor mounted on the upper heat ray fixing roller 17a for controlling temperature, for example, using a thermistor. TS2 is a lower metal roller 47.
For example, it is a temperature sensor using a thermistor for controlling temperature attached to a.

According to FIG. 6, the structure of the heat ray fixing roller 17a is such that, as shown in the cross section in FIG. 6A, the cylindrical light transmitting substrate 171a is formed of infrared rays or far infrared rays from a heat ray irradiation member 171g. Such as Pyrex glass, sapphire (Al ₂ O ₃ ), and CaF ₂ that transmit heat rays such as (having a thermal conductivity of (5.5 to 19.0) × 10 ⁻³ J / c
m · s · K, coefficient of linear expansion (0.4-8) × 10 ⁻⁶ /
° C) is mainly used, and in addition, a translucent resin using polyimide, polyamide, or the like (having a thermal conductivity of (2.5 to
3.4) × 10 ⁻³ J / cm · s · K) can also be used. The wavelength of the heat ray passing through the translucent substrate 171a is 0.1 to 20 μm, and preferably 0.3 to 3 μm.波長, preferably の of the wavelength of
Titanium oxide, aluminum oxide, zinc oxide, silicon oxide having an average particle diameter of 1 μm or less, preferably 0.1 μm or less, including primary and secondary particles, and having heat ray transmission properties (mainly infrared or far infrared ray transmission properties) The light-transmissive substrate 171a may be formed by dispersing fine particles of a metal oxide such as magnesium oxide, calcium carbonate, or the like in a resin binder. The average particle size including primary and secondary particles in the layer is 1μ.
m or less, preferably 0.1 μm or less is preferable for preventing light scattering and reaching the heat ray absorbing layer 171b. Therefore, the light-transmitting substrate 171a has poor heat conductivity.

The elastic layer 171d is formed of a rubber layer (base layer) that transmits heat rays (mainly infrared rays or far infrared rays) and is made of, for example, silicon rubber having a thickness of about 2 to 20 mm. For the elastic layer 171d, in order to cope with high speed, a method of improving thermal conductivity by blending a base rubber (silicon rubber) with a powder of a metal oxide such as silica, alumina or magnesium oxide as a filler is adopted. Conductivity is (1.3-1.6) × 10 ⁻³ J / cm
-It is preferable to use a rubber layer of about sK. When the thermal conductivity is increased, the rubber hardness generally tends to increase. For example, a rubber having a normal hardness of 40 Hs tends to have a hardness close to 60 Hs (JIS, A rubber hardness). Rubber hardness is 40-60
Hs is preferred. Elastic layer 171d of rotating member for fixing heat rays
Is mostly occupied by the base layer, and the amount of compression during pressurization is determined by the rubber hardness of the base layer. Elastic layer 171
The intermediate layer d is coated with a fluorine-based rubber having a thickness of 20 to 300 μm as an oil-resistant layer to prevent oil swelling. As the silicon rubber of the top layer of the elastic layer 171d, HT
V (high temperature volcan)
RTV (room t
emperature volcanizing) or L
TV (low temperature volcan)
is coated with a thickness equivalent to that of the intermediate layer. The wavelength of the heat ray passing through the elastic layer 171d is 0.1 to
Since it is 20 μm, and preferably 0.3 to 3 μm, as an agent for adjusting hardness and thermal conductivity, the particle size is 1/1/1 of the wavelength of the heat ray.
2. Titanium oxide having an average particle diameter of 1 μm or less, preferably 0.1 μm or less, preferably 1 μm or less, preferably 1/5 or less, including primary and secondary particles. Fine particles of metal oxides such as aluminum, zinc oxide, silicon oxide, magnesium oxide, and calcium carbonate are dispersed in a resin binder.
1d may be formed. It is preferable that the average particle diameter including the primary and secondary particles in the layer is 1 μm or less, preferably 0.1 μm or less, for preventing light scattering and reaching the heat ray absorbing layer 171b. By providing the elastic layer 171d,
The heat ray fixing roller 17a as the heat ray fixing rotation is configured as a soft roller having high elasticity.

As the heat ray absorbing layer 171b, 90 to 100% of the heat rays emitted from the heat ray irradiating member 171g and transmitted through the translucent substrate 171a and the elastic layer 171d are used.
Carbon black, graphite, iron black (Fe ₃ O _{4) is used} in the resin binder so that a heat ray absorbing layer 171b absorbs 100%, preferably 95% to 100%, of heat rays to form a heat ray fixing rotating member capable of instantaneous heating. ) And various ferrites and their compounds, copper oxide, cobalt oxide, red iron oxide (Fe
Using a heat ray absorbing member mixed with powder such as ₂ O ₃ ), the heat ray absorbing member having a thickness of 10 to 200 μm, preferably 20 to 100 μm is sprayed or applied to the outside (outer peripheral surface) of the elastic layer 171d. Formed by The heat ray absorption rate of the heat ray absorption layer 171b is lower than about 90%, for example, 20 to 8%.
If it is about 0%, the heat rays leak, and when the heat ray fixing roller 17a as a heat ray fixing rotating member is used for monochrome image formation due to the leaked heat rays, the heat ray fixing roller 17a is formed on the surface of the specific position of the heat ray fixing roller 17a by filming or the like. When the black toner adheres, heat is generated from the adhered portion due to the leaked heat rays, and heat is further generated by absorption of heat rays at that portion, thereby damaging the heat ray absorbing layer 171b. In addition, when used for forming a color image, the absorption efficiency of the color toner is generally low, and there is a difference in the absorption efficiency between the color toners. Therefore, the heat ray irradiation member 17
The heat ray absorption rate of the heat ray absorbing layer 171b is about 100%, which is equivalent to 90 to 90%, so that the heat ray emitted from 1 g and transmitted through the elastic layer 171d is completely absorbed in the heat ray fixing roller 17a.
100%, preferably 95 to 100%. Further, when the thickness of the heat ray absorbing layer 171b is less than 10 μm and thin, the heating rate due to absorption of heat rays in the heat ray absorbing layer 171b is high, but the heat ray absorbing layer 171b due to local heating by a thin film.
If the thickness of the heat ray absorbing layer 171b exceeds 200 μm and becomes too thick, heat conduction becomes poor or the heat capacity becomes large and instantaneous heating becomes difficult to be achieved. By setting the heat ray absorption rate of the heat ray absorption layer 171b to 90 to 100%, which is about 100%, preferably 95 to 100%, or setting the thickness of the heat ray absorption layer 171b to 10 to 200 μm, preferably 20 to 100 μm, Local heat generation in the absorption layer 171b is prevented, and uniform heat generation is performed. Further, the wavelength of the heat ray projected on the heat ray absorbing layer 171b is 0.1 to 20 μm, preferably 0.3 to 3 μm.
Therefore, an adjuster for hardness and thermal conductivity is added as a filler, but the average particle size including primary and secondary particles having a particle size of 、, preferably １ ／ or less of the wavelength of the heat ray is included. Is 1μ
m or less, preferably 0.1 μm or less, a fine particle of a metal oxide such as titanium oxide, aluminum oxide, zinc oxide, silicon oxide, magnesium oxide, calcium carbonate, etc. having a heat ray transmission property (mainly infrared or far infrared ray transmission property) of resin binder. 5 to 50% by weight dispersed in the heat ray absorbing layer 1
71b may be formed. Since the heat capacity of the heat ray absorbing layer 171b is thus reduced so that the temperature rises immediately, the temperature of the heat ray fixing roller 17a as a heat ray fixing rotating member is lowered, thereby causing the problem of uneven fixing. To prevent.

Further, a PFA (fluororesin) tube having a thickness of 30 to 100 μm is coated on the outside (outer peripheral surface) of the heat ray absorbing layer 171b separately from the heat ray absorbing layer 171b to improve the releasability from the toner. Or fluorinated resin (PF
(A or PTFE) A release layer 171c coated with a paint of 20 to 30 μm is provided (separation type).

Further, as shown in the cross section in FIG. 6B, carbon black, graphite, iron black (Fe ₃ O ₄ ), various ferrites and their compounds, copper oxide, cobalt oxide, red iron oxide (Fe ₂ O ₃ ), And a fluorocarbon resin (PFA or PB) which also serves as a binder and a release agent.
TFE) paint is mixed, and the heat-ray absorbing layer 171b and the release layer 171c described above with reference to FIG.
Formed on the outer side (outer peripheral surface) of the elastic layer 171d formed on the outer side (outer peripheral surface) of a, a roll-shaped heat ray fixing rotating member having elasticity is formed. Similarly to the above, the heat ray absorptivity of the dual-purpose layer 171B, which is about 100%, is set so that the heat ray emitted from the heat ray irradiation member 171g and transmitted through the translucent substrate 171a and the elastic layer 171d is completely absorbed.
100%, preferably 95 to 100%. Combined layer 1
When the heat ray absorptivity at 71B is lower than about 90%, for example, about 20 to 80%, the heat ray leaks, and when the heat ray fixing rotating member is used for monochrome image formation due to the leaked heat ray, filming or the like occurs. When the black toner adheres to the surface of the heat ray fixing rotating member at a specific position, heat is generated from the adhering portion due to the leaked heat rays, and the heat generated by the absorption of the heat rays is further superimposed on the portion to damage the dual-purpose layer 171B. In addition, when used for forming a color image, the absorption efficiency of the color toner is generally low, and there is a difference in the absorption efficiency between the color toners.
Therefore, the heat-absorbing rate of the dual-purpose layer 171B is approximately 100%, which is 90 to 100%, so that the heat rays emitted from the heat-ray irradiating member 171g and transmitted through the translucent substrate 171a are completely absorbed in the heat-ray fixing rotating member. , Preferably 95-1
00%. In addition, local heat generation in the dual-purpose layer 171B is also prevented, and uniform heat generation is performed. In addition, the combined use layer 17
Since the wavelength of the heat ray projected on 1B is 0.1 to 20 μm, preferably 0.3 to 3 μm, an adjuster for hardness and thermal conductivity is added as a filler. / 2, preferably 1/5 or less, a titanium oxide having an average particle diameter of 1 μm or less, preferably 0.1 μm or less, including primary and secondary particles, having a heat ray transmitting property (mainly infrared or far infrared ray transmitting property); The dual-purpose layer 171B may be formed by dispersing fine particles of a metal oxide such as aluminum oxide, zinc oxide, silicon oxide, magnesium oxide, and calcium carbonate in a resin binder.

According to FIG. 7, the heat ray absorbing layer 171 of the heat ray fixing roller 17a as a roll-shaped heat ray fixing rotating member is used.
It is preferable to generate heat inside the heat ray absorbing layer 171b by providing the above-mentioned concentration distribution of the heat ray absorbing member in b. Graph (a) shows the concentration distribution of the heat ray absorbing layer 171b.
As shown by, the interface on the side of the insulated elastic layer 171d is made to have a low concentration and is gradually increased toward the outer peripheral surface side so as to be higher in front of the outer peripheral surface side (with respect to the thickness t of the heat ray absorbing layer 171b, the elastic layer 171d 100 at 2/3 to 4/5 from the side)
% So as to be saturated.
As a result, the heat generation distribution due to the absorption of the heat rays in the heat ray absorption layer 171b is as shown in the graph (b).
The heat ray absorbing layer 171 has a maximum value near the central portion of the heat ray absorbing layer 71b.
It is formed in a parabolic shape having a minimum value near the interface b and the outer peripheral surface. Thereby, heat generation due to absorption of heat rays at the interface is reduced, and damage to the adhesive layer at the interface and heat ray absorption layer 171 are reduced.
b is prevented from being damaged. Further, the concentration distribution from the front side of the outer peripheral surface side (about ２ to ／ of the thickness t of the heat ray absorbing layer 171b from the side of the transparent substrate 171a) to the outer peripheral surface is saturated, In particular, even when the dual-purpose layer 171B is used, there is no influence even if the outer peripheral surface layer is shaved.
Note that a saturated layer may be formed as shown by a dotted line. In short, if the absorption is sufficiently performed inside, the influence of the concentration on the outside disappears. There is no influence of shaving. Further, the concentration distribution is provided with the inclination, and the heat generation distribution can be adjusted by changing the inclination angle.

As shown in FIG. 8, the outer diameter φ of the cylindrical translucent substrate 171a of the heat ray fixing roller 17a as a roll-shaped heat ray fixing rotating member is 15 to 60 mm.
As the thickness t, a thicker one is better in terms of strength and a thinner one is better in terms of heat capacity. However, from the relationship between strength and heat capacity, the outer diameter of the cylindrical light-transmitting base 171a is large. The relationship between φ and the thickness t is 0.05 ≦ t / φ ≦ 0.20, preferably 0.07 ≦ t / φ ≦ 0.14. When the outer diameter φ of the translucent substrate 171a is 40 mm, the thickness t of the translucent substrate 171a is 2 mm ≦ t ≦ 8 mm, preferably 2.8 mm ≦ t ≦ 5.6 mm. When t / φ is less than 0.05 in the translucent substrate 171a, the strength becomes insufficient, and when t / φ exceeds 0.20, the heat capacity increases and the heating of the heat ray fixing roller 17a is prolonged. Moreover, even if it says a translucent substrate, depending on a material, it is 1 to 1.
In some cases, about 20% of the heat rays may be absorbed, and a thinner one is preferred as long as the strength can be maintained.

By using the fixing device 17 described with reference to FIG. 5, the fixing device (nip portion) is resistant to deformation, and a fixing device for quick start fixing by instantaneous heating becomes possible. Melting of color toner that is difficult to fix by heat rays due to different spectral characteristics due to the pressure in the soft fixing section (nip section) due to the elasticity of the toner and the heating by the heat ray absorbing layer of the heat ray fixing rotating member. Is carried out satisfactorily, and it is possible to fix the color toner by instantaneous heating or quick start fixing with a short heating time. In particular, by using the image forming apparatus described with reference to FIG. 1, it is possible to perform instantaneous heating and fixing of a toner image in a quick start, which is described later with reference to FIG. Also, an energy saving effect can be obtained. Further, the pressure in the soft fixing unit (nip portion) due to the elasticity of the rotating member for heat ray fixing and the heating by the heat ray absorbing layer of the rotating member for heat ray fixing cause the frequency of use to be described in detail in FIG. In the case of fixing control of single-sided image formation on many surfaces, it is possible to perform instantaneous heating fixing of the toner image on the transfer material or quick start fixing with a short heating time, and soft fixing by elasticity of the rotating member for heat ray fixing. The fixing by the pressurization at the portion (nip portion) and the heating by the heat ray absorbing layer of the heat ray fixing rotating member causes the toner layer on the thick transfer material which is difficult to fix by the heat ray due to a difference in spectral characteristics. The superimposed color toner image is fused well, and the instantaneous heating of the color toner image can be fixed or the quick start fixing with a short heating time can be performed.

The fixing temperature control when applying the fixing device using the roll-shaped rotating member for hot-wire fixing for instant heating described in FIG. 5 to the image forming device for double-sided image formation in FIG. 1 will be described. This will be described with reference to FIGS. FIG.
FIG. 10 is a temperature control timing chart during double-sided image formation, FIG. 10 is a temperature control timing chart during front-side single-sided image formation, and FIG. 11 is a temperature control timing chart during back-side single-sided image formation.

As shown in FIG. 9, during the double-sided image formation, the recording sheet P passing through the fixing device 17 in response to the image formation on the front and back sides by the photosensitive drum 10 is set to the continuous printing by the single-sided image formation on the front side. Unlike the first embodiment, the heat roller is used intermittently for every other sheet. However, the upper heat roller 17a serving as the upper heat-fixing rotating member for fixing the toner image of the surface image is synchronized with the passage timing of the recording paper P. The heating roller 171g as a heating device is heated with the heating beam irradiating member 171g in an on state, and the upper roll-shaped portion having an alternating level between a fixing temperature setting value T during image formation suspension and an appropriate fixing temperature setting value T1 during image formation is provided. The temperature of the heat ray fixing rotating member is controlled. At this time, since the formation of the two-sided image is performed intermittently every other sheet, the non-passing time of the recording paper P is long, so that the temperature control and the temperature can be made uniform and the heat capacity for the upper instantaneous heating with a small heat capacity is small. The surface image can be fixed also by the heat ray fixing roller 17a as a roll-shaped heat ray fixing rotating member.

On the other hand, a metal roller 4 as a lower fixing rotating member for fixing the toner image of the back side image.
Reference numeral 7a denotes a lower fixing rotating member for heating by turning on the halogen heater 471c before the recording paper P passes during copying by double-sided image formation so as to maintain an appropriate fixing temperature set value T2 during image formation. Is controlled.

The temperature control is performed by fixing temperature setting values T, T1, T2 stored in advance in the ROM and temperature sensors TS1, T2.
The detection is performed through the control unit via the comparison circuit by the detection in S2 (see FIG. 4).

In FIG. 9, the temperature control of the upper heat ray fixing rotating member is performed in an area sandwiching the front and rear ends of the recording paper P in synchronization with the passage timing of the recording paper P.
It is necessary to set the temperature control timing earlier, and furthermore, to always set the fixing temperature set value T1 during the printing operation.

Further, as shown in FIG. 10, when forming a single-sided image on the front side, the conveyance timing of the recording paper P passing through the fixing device 17 for forming an image on the front side by the photosensitive drum 10 is set to the double-sided image formation or the single side only. Unlike continuous printing in image formation on the back side, the image formation is performed continuously in response to continuous image formation on the front side by the photoconductor drum 10, but is used for fixing a heat-ray in the form of an upper roll for fixing a toner image of a front side image. The heat ray fixing roller 17a as a rotating member is heated by turning on a heat ray irradiation member 171g, which is a heat ray irradiation unit, in synchronization with the passage timing of the recording paper P, and a fixing temperature set value T during image formation suspension and a fixing temperature set value T during image formation. The temperature control of the upper heat ray fixing rotating member at an alternate level with the appropriate fixing temperature set value T1 is performed.

On the other hand, a metal roller 4 as a lower fixing rotating member for fixing the toner image of the back side image.
7a, the heating temperature control of the lower fixing rotating member is performed such that the heating control is not performed during the copying by the one-sided image formation of the front surface, or the fixing temperature setting value T during the pause of the image formation is maintained. Done.

The temperature control is performed through the control unit via a comparison circuit based on the fixing temperature set values T and T1 stored in the ROM in advance and the detection by the temperature sensors TS1 and TS2 (see FIG. 4).

In FIG. 10, the temperature control of the upper heat ray fixing rotary member is performed in an area sandwiching the front and rear ends of the recording paper P in synchronization with the passage timing of the recording paper P. However, when the linear velocity is high, the temperature control is performed. It is necessary to set the timing earlier, and furthermore, to always set the fixing temperature set value T1 during the printing operation.

Further, as shown in FIG. 11, when forming the one-sided image on the back side, the conveyance timing of the recording paper P passing through the fixing device 17 in response to the image formation on the back side by the intermediate transfer belt 14a is set to the one-sided image on the front side. Unlike the continuous printing by forming, the printing is performed intermittently every other sheet. However, the metal roller 47a as a lower fixing rotating member for fixing the toner image of the back side image is used during the copying by the one side image formation on the back side.
Before the recording paper P passes, the halogen heater 471c is turned on and heated, and the heating temperature control of the lower fixing rotating member is performed so as to maintain an appropriate fixing temperature set value T2 during image formation.

On the other hand, the upper heat-fixing roller 17a as a heat-fixing rotary member in the form of a roll is not subjected to heating control during copying by forming a single-sided image on the back surface, or is stopped during image formation. The temperature control of the upper heat ray fixing rotating member is performed so as to maintain the fixing temperature set value T.

As shown by the alternate long and short dash line in FIG. 11, the upper heat ray fixing rotating member turns on the heat ray irradiating member 171g in synchronization with the passage timing of the recording paper P during copying by the single-sided image formation on the back side. More preferably, heating is performed so as to maintain an appropriate fixing temperature set value T1 during forming. By heating with the upper heat ray fixing rotating member being turned on, the leading end of the nip portion T is overheated, and the leading end of the recording paper P is heated. When the toner image is added to the nip portion, the toner image of the single-sided image on only the rear surface is fixed favorably without disturbing the toner image. At this time, the temperature control of the upper heat ray fixing rotary member is performed in a region sandwiching the front and rear ends of the recording paper P, but when the linear velocity is high, the temperature control timing is set earlier.
Further, it is necessary to always set the fixing temperature set value T1 during the printing operation.

The temperature control is performed by setting the fixing temperature set values T, T2, (T1) stored in advance in the ROM and the temperature sensor TS.
1, through the control unit via the comparison circuit by the detection by TS2 (see FIG. 4).

According to FIGS. 9 to 11, when changing from single-sided image formation to double-sided image formation or when starting single-sided image formation, single-sided image formation on the front surface has a small heat capacity and quick start (instant start). )
The fixing is carried out by a rotatable heat-ray fixing rotating member that can fix the toner image of the surface image according to the change without providing a warm-up time. Further, when the front surface is changed from single-sided image formation to double-sided image formation or when double-sided image formation is started, since the rear surface image needs to be fixed by the fixing rotating member having a large heat capacity, the warm-up time of the fixing rotating member is required. Required. The warming-up time becomes long when a fixing rotary member having a high linear velocity and a large heat capacity is required. In the case of a fixing rotating member having a small heat capacity at a low speed, a warm-up time may not be required in some cases. In addition, a warm-up time is also required when forming a single-sided image on only the back side.

Since the formation of the double-sided image is performed intermittently every other sheet, the heat capacity is sufficient even with the heat ray fixing rotating member having a small heat capacity, and the surface image can be fixed by the heat ray fixing rotating member.

It should be noted that the image forming apparatus is set so that the temperature control is automatically performed in the double-sided image forming state at the time of the initial operation when the power switch is turned on or when the mode is changed from the pause mode to the print operation mode. Further, it is also possible to control so that the heating control of the lower fixing rotating member is turned off when the unused time passes a certain time.

With the configuration described above, different energy consumptions are performed when forming a single-sided image only on the front surface, when forming a single-sided image only on the back surface, or when forming a double-sided image.
Compared to conventional fixing devices that use heating elements for the upper and lower rollers, proper energy consumption is performed during single-sided image formation and double-sided image formation, respectively, so that both consume less energy, and the conventional upper and lower rollers generate heat. Compared to a fixing device using a body or a film fixing device using a ceramic heater, a nip width in the fixing area is wider and higher fixing performance is obtained. A forming device is provided.

The flange member provided on the rotatable member for hot-wire fixing, and the pressing and driving of the rotatable member for hot-wire fixing and the rotatable fixing member will be described with reference to FIG. 12 or FIG. 12 is a cross-sectional configuration diagram of a roll-shaped rotatable fixing member provided on the upper side and a roll-shaped fixing rotatable member provided on the lower side. FIG. It is a side view which shows drive. In the following description, one end of both rollers will be described, but the other end has the same structure.

According to FIG. 12 or FIG. 13, as described above, the heat ray fixing roller 17a as a heat ray fixing rotating member for fixing the toner image of the surface image includes a cylindrical translucent substrate 171a, An elastic layer 171d, a heat ray absorbing layer 171b, and a release layer 171c are provided in this order on the outer side (outer peripheral surface) of the light-transmitting substrate 171a, and heat rays using, for example, a halogen lamp or a xenon lamp are provided inside the light-transmitting substrate 171a. It is configured as a soft roller on which 171 g of a heat ray irradiating member as an irradiating means is arranged. The heat ray fixing roller 17a as a heat ray fixing rotating member is configured as a highly elastic soft roller as described above. Heat ray irradiation member 171
The heat ray emitted from g is absorbed by the heat ray absorbing layer 171b to form a roll-shaped heat ray fixing rotating member capable of instantaneous heating.

The metal roller 47a as a fixing rotating member for fixing the toner image of the back side image is made of, for example, iron material, steel material (having a thermal conductivity of (0.15-0.
76) It is formed of a cylindrical metal pipe 470 using × 10 ⁻³ J / cm · s · K), and is configured as a hard roller in which a halogen heater 471c is disposed inside the metal pipe 470.

A nip T having a convex upper side is formed between the upper soft roller and the lower hard roller, and the toner image is fixed.

The cylindrical translucent substrate 171a of the heat ray fixing roller 17a as a heat ray fixing rotating member for fixing the toner image of the surface image is mainly made of Pyrex glass, sapphire (Al ₂ O ₃ ), CaF _2. A ceramic material having a thickness of about 2 to 10 mm (a coefficient of linear expansion of (0.4 to 8) × 10 ⁻⁶ / ° C., thermal conductivity) that transmits heat rays such as infrared rays or far infrared rays from 171 g of a heat ray irradiation member such as (5.5 to 19.0) × 10 ⁻³ J / cm · s · K) is used, but a metal member such as aluminum or stainless steel is attached to the end of the outer peripheral surface of the cylindrical light-transmitting substrate 171a. (Linear expansion coefficient is (10-30) × 10 ^-6 / ° C.)
Flange 9 as a cylindrical flange member of about 3 mm
10 is fitted with a width of about 10 to 50 mm, and attached by, for example, an adhesive or the like.

Even if the thermal expansion of the flange member is large, since it is provided on the outside, unlike the inside, the transparent substrate is not damaged by the thermal expansion.

Transparent substrate 1 with flange 910 fitted
The elastic layer 17 is provided on the outer side (outer peripheral surface) of the elastic layer 71a so as to cover the fitting portion 911 of the flange 910 with the transparent substrate 171a.
1d, a heat ray absorbing layer 171b and a release layer 171c are formed in that order.

The tip 9 as a rotation axis of the flange 910
12 is fitted in a bearing B1 as a bearing member fitted in a groove (no number) of the lever 102, and the heat ray fixing roller 17a is attached to the lever 102.

On the other hand, a cylindrical throttle portion 471 at the end of the metal pipe 470 of the metal roller 47a as a fixing rotating member for fixing the toner image of the back side image is a bearing as a bearing member fitted into the side plate 101. The metal roller 47a is attached to the side plate 101 by being fitted into B2. Further, the fixing drive gear G is fitted into the aperture portion 471, and the fixing drive gear G is fixed to the metal roller 47a by a screw or a pin.
Fixed to the end.

The bearing B1 for holding the heat ray fixing roller 17a is supported by a retaining spring SP1 using a piano wire or a leaf spring attached to the lever 102, for example. With the axis J1 fixed to the
02 is rotatably attached to the shaft J1. Further, a coil-shaped compression spring SP2 using, for example, a piano wire having a wire diameter of about 1.5 to 3.0 mm attached to a shaft J2 fixed to the other end of the lever 102 is fixed to the side plate 101. J3 and the heat ray fixing roller 17a
Is pressed against the metal roller 47a.

A heat ray irradiating member 171g is inserted inside the heat ray fixing roller 17a, and is held at the center position of the heat ray fixing roller 17a by terminals JT1 at both ends. A halogen heater 471c is inserted inside the metal roller 47a, and is held at the center position of the metal roller 47a by terminals JT2 at both ends.

The heat ray irradiating member 17 of the heat ray fixing roller 17a
The light emission area of 1 g is substantially the same as the heat generation area of the halogen heater 471 c of the metal roller 47 a, and has a width inside the fitting portion 911 of the flange 910 and outside the pass area of the transfer material size (maximum transfer material size). Provided.

As described above, the provision of the flange member outside the light-transmitting substrate prevents the light-transmitting substrate from being damaged by the pressure applied to the heat ray fixing rotating member. In particular, even if the thermal expansion of the flange member using the metal member is larger than the thermal expansion of the light-transmitting substrate mainly using the pipe made of ceramic material, the flange member using the metal member provided on the outside has the light transmitting property. The base is protected, and the end of the translucent base is prevented from being damaged by the pressure applied to the end of the heat ray fixing rotating member. Further, since the outer diameter accuracy of the light-transmitting substrate using a pipe made mainly of ceramic material is formed so as to be superior to the inner diameter accuracy, the rotating member for heat ray fixing rotated by the flange member attached to the outer peripheral surface of the light-transmitting substrate. The center is positioned with high precision, and wrinkles of the transfer material at the time of fixing are prevented.

Further, the fixing driving gear G fixed to a metal roller 47a as a fixing rotating member used as a lower hard roller is driven and rotated by the gear G1 through a driving system connected to the fixing driving motor M1, and the nip portion is formed. T
Then, the heat ray fixing roller 17a as a heat ray fixing rotating member used as the upper soft roller is driven to rotate. This prevents direct pressure from the drive system from being applied to the rotating member for heat ray fixing, and prevents the transparent substrate from being damaged when the rotating member for heat ray fixing is driven.

Another example of the end processing of the heat ray fixing rotating member will be described with reference to FIG. FIG. 14 is a diagram showing another example of the end processing of the heat ray fixing rotating member. In the following description, one end of both rollers will be described, but the other end has the same structure.

According to FIG. 14, as described above, the heat ray fixing roller 17a as a heat ray fixing rotating member for fixing the toner image of the surface image is a cylindrical translucent base member 17a.
1a, an elastic layer 171d, a heat ray absorbing layer 171b, and a release layer 171c provided in this order on the outer side (outer peripheral surface) of the light-transmitting base 171a, and a halogen lamp or a xenon lamp is provided inside the light-transmitting base 171a. It is configured as a soft roller on which 171 g of a heat ray irradiation member, which is a used heat ray irradiation means, is arranged. The heat ray fixing roller 17a as a heat ray fixing rotating member is configured as a highly elastic soft roller as described above. The heat rays emitted from the heat ray irradiating member 171g are absorbed by the heat ray absorbing layer 171b to form a roll-shaped heat ray fixing rotating member capable of instantaneous heating.

The cylindrical translucent substrate 171a of the heat ray fixing roller 17a as a heat ray fixing rotating member for fixing the toner image of the surface image is mainly made of Pyrex glass, sapphire (Al ₂ O ₃ ), CaF _2. A ceramic material having a thickness of about 2 to 10 mm (a coefficient of linear expansion of (0.4 to 8) × 10 ⁻⁶ / ° C., thermal conductivity) that transmits heat rays such as infrared rays or far infrared rays from 171 g of a heat ray irradiation member such as (5.5 to 19.0) × 10 ⁻³ J / cm · s · K) is used, but a metal member such as aluminum or stainless steel is attached to the end of the outer peripheral surface of the cylindrical light-transmitting substrate 171a. (Linear expansion coefficient is (10-30) × 10 ^-6 / ° C.)
Ring 920 as a cylindrical ring member of about 3 mm
Is widely fitted with a width of about 20 to 50 mm,
The collar 921 stops at the end of the translucent substrate 171a. The ring 920 is attached to the translucent substrate 171a by, for example, an adhesive.

Even if the thermal expansion of the ring member is large, since it is provided on the outer side, unlike the inner side, the transparent substrate is not damaged by thermal expansion.

Light-transmitting base 17 into which ring 920 is fitted
1a, the elastic layer 171d, the heat ray absorbing layer 171b, and the release layer 17 are formed so as not to cover the ring 920 inside the fitting portion of the ring 920 with the light-transmitting base 171a.
1c are formed in that order.

The step 922 of the ring 920 is
The hot-wire fixing roller 17a is attached to the lever 102 by being fitted into a bearing B1 as a bearing member fitted into the groove No. 02 (no reference numeral).

A heat ray fixing roller 17a as a heat ray fixing rotating member is assembled in the same manner as described with reference to FIG. A heat ray irradiating member 171g is inserted inside the heat ray fixing roller 17a, and is held at the center position of the heat ray fixing roller 17a by terminals JT1 at both ends.

Heat ray irradiating member 17 of heat ray fixing roller 17a
The light emission area of 1 g is substantially the same as the heat generation area of the halogen heater 471 c of the metal roller 47 a (not shown, see FIG. 13), inside the fitting portion of the ring 920 and further inside the end of the elastic layer 171 d. In this case, the width is provided outside the passing area of the transfer material size (maximum transfer material size).

As described above, the provision of the ring member outside the light-transmitting substrate prevents the light-transmitting substrate from being damaged by the pressure applied to the heat ray fixing rotating member. In particular, even if the thermal expansion of the ring member using the metal member is larger than the thermal expansion of the light transmitting substrate mainly using the ceramic pipe, the light transmitting substrate is formed by the ring member using the metal member provided outside. Is protected, and damage to the end of the translucent substrate due to the pressure applied to the end of the heat ray fixing rotating member is prevented. In addition, since the outer diameter accuracy of the light-transmitting substrate using a pipe made mainly of a ceramic material is formed so as to be superior to the inner diameter accuracy, the rotating member for heat ray fixing rotated by the ring member attached to the outer peripheral surface of the light-transmitting substrate is used. The center is positioned with high precision, and wrinkles of the transfer material at the time of fixing are prevented.

[0109]

According to the first to seventh aspects of the present invention, the end of the transparent substrate is prevented from being damaged by the pressure applied to the heat ray fixing rotating member.

According to the eighth aspect, breakage of the light-transmitting substrate during driving of the heat ray fixing rotating member can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of a fixing device and an image forming apparatus using the fixing device according to the present invention.

FIG. 2 is a diagram illustrating a toner image forming state in the image forming apparatus of FIG. 1;

FIG. 3 is a diagram illustrating an example of a document image reading unit.

FIG. 4 is a control circuit block diagram of the image forming apparatus.

FIG. 5 is an explanatory diagram illustrating a structure of a fixing device.

FIG. 6 is an enlarged cross-sectional configuration diagram of a roll-shaped rotating member for heat ray fixing.

FIG. 7 is a diagram showing a concentration distribution of a heat ray absorbing layer of a roll-shaped heat ray fixing rotating member.

FIG. 8 is a diagram showing an outer diameter and a thickness of a light-transmitting substrate of a roll-shaped rotating member for fixing heat rays.

FIG. 9 is a temperature control timing chart during double-sided image formation.

FIG. 10 is a temperature control timing chart when forming a single-sided image on the front surface.

FIG. 11 is a temperature control timing chart when forming a single-sided image on the back surface.

FIG. 12 is a cross-sectional configuration diagram of a roll-shaped heat ray fixing rotating member provided on an upper side and a roll-shaped fixing rotating member provided on a lower side.

FIG. 13 is a side view showing the pressing and driving of the upper and lower rollers of FIG.

FIG. 14 is a diagram illustrating another example of the end processing of the heat ray fixing rotating member.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor drum 11 scorotron charger 12 exposure optical system 13 developing device 14a intermediate transfer belt 14c transfer device 14g backside transfer device 17 fixing device 17a heat ray fixing roller 47a metal roller 171a translucent substrate 171B combined layer 171b heat ray absorbing layer 171c Mold layer 171d Elastic layer 171g Heat ray irradiation member 910 Flange 920 Ring 921 Flange G Fixing drive gear P Recording paper

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Kuki Nagase, Inventor 2970, Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H033 AA25 BB03 BB13 3K058 AA02 AA22 AA45 AA64 AA86 AA87 BA18 CE12 CE17 CE29 DA02 DA06 DA26 3K092 PP18 QA02 QB26 QC22 QC37 RA03 RC16 RC20 RD11 RD16 RD22 TT13 TT27 VV02 VV03 VV16 VV22

Claims (8)

[Claims] 1. A fixing device for fixing a toner image on a transfer material to the transfer material by applying heat and pressure, comprising: a cylindrical light-transmitting base in which a heat ray irradiating means for emitting heat rays is arranged; An elastic layer and a heat-absorbing layer are provided outside the light-transmitting base to form a heat-fixing rotary member in the form of a roll, and flange members having a rotation axis are provided at both ends of the light-transmitting base. Fixing device. 2. The fixing device according to claim 1, wherein the elastic layer or the heat ray absorbing layer is provided from above the flange member. 3. The fixing device according to claim 1, wherein the flange member is made of metal. 4. A fixing device for fixing a toner image on a transfer material to the transfer material by applying heat and pressure, comprising: a cylindrical light-transmitting substrate in which a heat ray irradiating means for emitting heat rays is arranged; An elastic layer and a heat ray absorbing layer are provided outside the light-transmitting substrate to form a roll-shaped rotating member for fixing heat rays, and a wide ring member is provided at an end of the light-transmitting substrate, and the ring member is provided. And a bearing member for the heat ray fixing rotating member is provided through the fixing device. 5. A stopper provided at an end of the ring member to serve as a stop with the translucent base.
3. The fixing device according to claim 1. 6. The fixing device according to claim 4, wherein the elastic layer or the heat ray absorbing layer is provided inside the ring member. 7. The fixing device according to claim 4, wherein the ring member is made of metal. 8. A fixing device for fixing a toner image on a transfer material to the transfer material by applying heat and pressure, comprising: a cylindrical light-transmitting base in which a heat ray irradiating means for emitting heat rays is arranged; An elastic layer and a heat ray absorbing layer are provided on the outer side of the light-transmitting substrate to form a roll-shaped heat ray fixing rotating member, and a fixing rotating member is provided opposite to the heat ray fixing rotating member. A driving member for driving and rotating the heat ray fixing rotating member to be driven to rotate.