JP2003066762A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device which can reduce the surface unevenness of a paper-feeding part in a heating roller. SOLUTION: The fixing device which passes an unfixed toner image on a transfer material between a heating roller and a pressure roller to press the heating roller, hot-presses and melt-fixes the toner image on the transfer material. The fixing device is provided with a temperature sensor which measures surface temperatures at a plurality of positions in the axial longitudinal direction of the heating roller, and a cooling means which determines the cooling region of the surface in the axial longitudinal direction of the heating roller on the basis of a result of temperature measurement by the temperature sensor, and then cools the cooling region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device, and more particularly to a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, and a multi-function peripheral having these functions.

[0002]

2. Description of the Related Art As a fixing device used in an image forming apparatus, an unfixed toner image on a transfer material is passed between a heating roller and a pressure roller to heat and press the toner image on the transfer material. There is known a device for welding the transfer material to the transfer material.
As this fixing device, a heating roller provided with a light-transmissive elastic layer on the outer side of a cylindrical light-transmissive substrate and a heat ray absorbing layer on the outer side thereof is adopted, and a heating element provided inside the light-transmissive substrate ( There is known a quick-start type fixing device in which a heat ray from a halogen heater is absorbed by a heat ray absorbing layer and then a toner image on a transfer material is heated and pressed to fix the toner image.

Further, in a fixing device for heat-fixing at least two types of transfer materials having different width sizes, a cooling fan is provided for cooling the non-sheet passing portion of the heating roller through which the transfer material having a small width does not pass, and is cooled. There is known a device that sends air from a fan to the non-sheet passing portion of the heating roller to cool the non-sheet passing portion of the heating roller.

[0004]

However, in the quick-start type fixing device, the amount of heat transfer in the longitudinal direction of the shaft is small. Therefore, when the non-sheet passing portion is cooled, the surface temperature near the end of the sheet passing portion is reduced. However, there is a problem that the temperature of the paper passing portion tends to be non-uniform.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device which can reduce the surface temperature unevenness of a sheet passing portion and can heat-fix a transfer material uniformly. Particularly in a quick start type fixing device, it is to reduce unevenness in the surface temperature of the paper passing portion of the heating roller.

[0006]

The above object of the present invention can be achieved by any of the following means. That is, (1) a fixing device for passing an unfixed toner image on a transfer material between a heating roller and a pressure roller in pressure contact with the heating roller to heat and press the toner image on the transfer material to fuse the toner image. In the heating roller, a temperature sensor for measuring the surface temperature at a plurality of positions in the axial direction of the heating roller, and a cooling region of the surface of the heating roller in the axial direction is determined based on the temperature measurement result by the temperature sensor. And a cooling unit that cools the fixing device.

(2) In the fixing device described in (1) above, it is possible to control and maintain the heating roller at a predetermined temperature by changing the amount of heat of the heating source of the heating roller based on the temperature measurement result of the temperature sensor. Characterizing fixing device.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of an image forming apparatus using a fixing device according to the present invention will be described first. FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus using a fixing device according to the present invention, FIG. 2 is a configuration diagram showing the structure of the fixing device of the present invention, and FIG. 3 is an enlarged cross-sectional view of the heating roller of FIG. It is a block diagram.

As shown in FIG. 1, a photosensitive drum 10 as an image forming body is provided on the outer circumference of a cylindrical base body formed of a transparent member such as glass or a transparent acrylic resin.
A transparent conductive layer and a photoconductor layer of an organic photosensitive layer (OPC) are formed.

The photosensitive drum 10 is rotated clockwise by the power from a driving source (not shown) with the transparent conductive layer being grounded.

The exposure beam for image exposure can impart an appropriate contrast to the photo-attenuation characteristic (photo-carrier generation) of the photo-conductor layer in the photo-conductor layer of the photoconductor drum 10 which is the image forming point. It has an exposure light amount of a wavelength. As a material of the translucent substrate, an acrylic resin, particularly a polymer of a methacrylic acid methyl ester monomer, is excellent in translucency, strength, accuracy, surface property and the like. As the translucent conductive layer, a metal thin film made of indium tin oxide (ITO), tin oxide, lead oxide, indium oxide or the like and maintaining translucency is used. Further, various organic photosensitive layers (OPC) can be used as the photoconductor layer.

Scorotron charger 1 as charging means
1. An exposure optical system 12 as an image writing unit and a developing unit 13 as a developing unit, respectively, an image forming process for each color of yellow (Y), magenta (M), cyan (C) and black (K). Prepared for use in the direction of rotation of the photosensitive drum 10 indicated by the arrow in FIG.
They are arranged in the order of C and K.

Scorotron charger 11 as charging means
Is attached close to the photoconductor drum 10 in a direction orthogonal to the moving direction of the photoconductor drum 10 (direction perpendicular to the paper surface in FIG. 1), and is kept at a predetermined potential with respect to the organic photoconductor layer of the photoconductor drum 10. The control drum (not shown) and a corona discharge electrode 11a, for example, a sawtooth electrode is used, and a corona discharge having the same polarity as the toner is used to perform a charging action (negative charging in the present embodiment). A uniform electric potential is applied to.

The exposure optical system 12 for each color has a linear exposure element in which a plurality of LEDs (light emitting diodes) as light emitting elements for the image exposure light are arranged in an array in parallel with 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 holder 20
The exposure optical system 12 for each color is attached and housed inside the base of the photoconductor drum 10.

The exposure optical system 12 as an image writing means for each color sets the exposure position on the photosensitive drum 10 between the scorotron charger 11 and the developing device 13 to the developing device 13 with respect to the photosensitive member. The drum 10 is arranged inside the photoconductor drum 10 while being provided on the upstream side in the rotation direction of the drum 10.

The exposure optical system 12 performs image processing based on the image data of each color sent from a separate computer (not shown) and stored in the memory, and then forms an image on the uniformly charged photosensitive drum 10. Exposure is performed to form a latent image on the photoconductor drum 10. The emission wavelength of the light emitting element is usually Y, M,
It is preferable that the toner of C has a high light transmittance in the range of 680 to 900 nm.

The developing device 13 as a developing means for each color is
Yellow (Y), magenta (M), cyan (C) inside
Alternatively, a black (K) two-component developer is accommodated, and each has a developing sleeve 13a 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. ing.

In the developing area, the developing sleeve 13a is kept in non-contact with the photoconductor drum 10 with a predetermined gap by an abutting roller (not shown), and is placed in the closest position to the rotation direction of the photoconductor drum 10. The developing bias voltage is applied to the developing sleeve 13a at the time of development. The developing bias voltage is a DC voltage having the same polarity as the toner (negative polarity in this embodiment) or a DC voltage superposed with the AC voltage AC. By doing so, non-contact reversal development is performed on the exposed portion of the photoconductor drum 10.

The developing device 13 non-contactly charges 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 to the charging polarity of the photosensitive drum 10. Reverse development is performed with toner having the same polarity as that of (the photosensitive drum is negatively charged in the present embodiment, and the toner has a negative polarity).

When the image forming body drive motor (not shown) is started by the start of the image formation, the photosensitive drum 10 is rotated in the clockwise direction shown by the arrow in FIG. 1, and at the same time, the photosensitive body is charged by the Y scorotron charger 11. Application of electric potential to the drum 10 is started. After the potential is applied to the photoconductor drum 10, the exposure (image writing) by the electric signal corresponding to the first color signal, that is, the Y image data is started in the Y exposure optical system 12 to rotate the photoconductor drum 10. By scanning, an electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface thereof. The latent image is reversely developed by the Y developing device 13 in a non-contact state, and a yellow (Y) toner image is formed on the photosensitive drum 10.

Next, the photosensitive drum 10 is provided with an M scorotron charger 11 on the yellow (Y) toner image.
Potential is applied by the charging action of M to expose the optical system 12 of M.
Exposure (image writing) by an electric signal corresponding to the second color signal of M, that is, the image data of magenta (M),
The non-contact reversal development by the developing device 13 forms a magenta (M) toner image on the yellow (Y) toner image.

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

As described above, in this embodiment, Y, M,
The exposure of the organic photosensitive layer of the photoconductor drum 10 by the C and K exposure optical system 12 is performed from the inside of the photoconductor drum 10 through a light-transmitting substrate. 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 toner image previously formed, which is preferable. Photoconductor drum 1
The exposure may be performed from the outside of 0.

On the other hand, the transfer material P is sent out from the paper feeding cassette 15 by a sending roller (no code), is fed by a feeding roller (no code), and is conveyed to the timing roller 16.

The transfer material P is synchronized with the color toner image carried on the photosensitive drum 10 by driving the timing roller 16, and the paper charger 1 as a paper charging means.
It is attracted to the conveyor belt 14a by the charging of 50 and is fed to the transfer area. The transfer material P, which is closely conveyed by the conveyance belt 14a, is rotated around the photosensitive drum 10 by a transfer device 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 the transfer area. The color toner images on the surface are collectively transferred to the transfer material P.

The transfer material P on which the color toner image is transferred is
The charge is removed by a paper separation AC static eliminator 14h serving as a transfer material separating unit, separated from the conveyor belt 14a, and conveyed to the fixing device 17.

The transfer material P is sandwiched by the nip portion N formed between the heating roller 17a and the pressure roller 47a, and the color toner image on the transfer material P is fixed and transferred by applying heat and pressure. The material P is sent by the paper discharge roller 18 and is discharged to the tray above the apparatus.

After the transfer, the toner remaining on the peripheral surface of the photosensitive drum 10 is cleaned by a cleaning blade 19 provided in a cleaning device 19 as an image forming member cleaning means.
It is cleaned by a. The photoconductor 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. 2, the fixing device 17 includes a heating roller 17a serving as an upper roll-shaped heat ray fixing rotary member for fixing a color toner image, and a lower side forming a pair with the upper heating roller 17a. Roll-shaped pressure roller 47a
The heating roller 17a has an internal center,
Depending on the light source, a halogen lamp 171g or a xenon lamp (not shown) that emits heat rays such as infrared rays or far infrared rays containing visible light is provided. TS1 is a non-contact type temperature sensor attached to the upper heating roller 17a for detecting the infrared radiation amount for temperature control, and TS5 is attached to the lower pressure roller 47a. It is a non-contact type temperature sensor that detects the amount of infrared radiation for performing temperature control. Details will be described later.

The heating roller 17a, which is provided on the upper side and serves as a rotating member for fixing the heat ray in the form of a roll, fixes the fixing separation claw TR in the rotation direction of the heating roller 17a from the position of the nip portion N.
3, cleaning roller TR1, heat homogenizing roller TR
4. An oil application roller TR2 is provided, and the heating roller 1 is provided by the oil application roller TR2 in which a felt member impregnated with oil is wrapped around a cylindrical aluminum pipe or paper tube.
Oil is applied to 7a. Cleaning roller TR1
Thus, the toner and oil on the peripheral surface of the heating roller 17a are cleaned. The transfer material after fixing is separated by the fixing separation claw TR3. Further, the heat distribution of heat on the peripheral surface of the heating roller 17a heated by the heat ray absorbing layer 171b is made uniform by the heat homogenizing roller TR4 using a metal roller member having good thermal conductivity such as an aluminum material or a stainless steel material or a heat pipe. To be done. The heat homogenizing roller TR4 equalizes the temperature unevenness in the vertical direction and the horizontal direction of the heating roller 17a accompanying the passage of the transfer material.

The heating roller 17a provided on the upper side for fixing the toner image on the transfer material is a cylindrical light-transmitting substrate 171a and a light-transmitting substance on the outer side (outer peripheral surface) of the light-transmitting substrate 171a. Elastic layer 171d, heat ray absorbing layer 171b, and release layer 1
71c in that order, or as will be described in detail in FIG. 3 in the latter part, a cylindrical light-transmitting substrate 171a and a light-transmitting elastic layer 17 on the outer side (outer peripheral surface) of the light-transmitting substrate 171a.
1d and the outside (outer peripheral surface) of the light-transmitting elastic layer 171d,
It is configured as a soft roller in which the heat ray absorbing layer 171B including the heat ray absorbing layer 171b and the release layer 171c described above is provided in that order. A halogen lamp 171g or a xenon lamp (not shown) that emits heat rays such as infrared rays or far infrared rays containing visible light depending on the light source is provided in the center of the light-transmitting substrate 171a. The heating roller 17a is
As will be described later, the soft roller has high elasticity. The heat ray emitted from the halogen lamp 171g or the xenon lamp (not shown) is absorbed by the heat ray absorbing layer 171b (or the heat ray absorbing layer 171B) to form a roll-shaped heat ray fixing rotary member capable of rapid heating.

The lower roll-shaped pressure roller 47a paired with the upper heating roller 17a is a cylindrical metal pipe 471a made of, for example, an aluminum material, and the outer circumference of the metal pipe 471a. The surface is formed as a soft roller having a rubber roller 471b formed of a thick rubber layer using a silicon material, for example. Further, there is provided a heat homogenizing roller TR4 using a metal roller member having good thermal conductivity, such as an aluminum material or a stainless material, which comes into contact with the surface of the rubber roller 471b and is driven to rotate.
A halogen lamp 47 as a heat source is provided in the center of 71a.
1c may be provided. A flat nip portion N is formed between the upper soft roller and the lower soft roller to fix the toner image.

As shown in FIG. 3, the heating roller 17a has a cylindrical translucent substrate 171a having a thickness (wall thickness) of 1 to 5 mm as shown in the cross section of FIG. 3 (a). A ceramic material such as Pyrex (R) glass or sapphire that transmits heat rays such as infrared rays or far infrared rays from a halogen lamp 171g or a xenon lamp (not shown) is mainly used.

The light-transmitting elastic layer 171d is made of, for example, silicon rubber or fluororubber, and is formed of a heat ray-transmissive silicon rubber layer or a fluororubber layer (base layer) which transmits heat rays. In order to increase the speed of the light-transmitting elastic layer 171d, the base layer is mixed with a powder of a metal oxide such as silica, alumina, or magnesium oxide to improve the thermal conductivity. Layer or fluororubber layer is used. Since the silicone rubber layer and the fluororubber layer have lower thermal conductivity than the translucent substrate 171a using a glass member, they function as a heat insulating layer. Light-transmitting elastic layer 171d
The base layer occupies most of the above, and the amount of compression at the time of pressurization is determined by the rubber hardness of the base layer. The intermediate layer of the translucent elastic layer 171d is coated with fluorine rubber as an oil resistant layer for preventing oil swelling. In addition, the transparent elastic layer 1
Since the wavelength of the heat ray passing through 71d is 0.1 to 20 μm, the filler used as the hardness and thermal conductivity adjusting agent described above has a particle size of ½ or less of the wavelength of the heat ray.
The transparent elastic layer 171d is formed by dispersing fine particles of a heat ray permeable metal oxide such as titanium oxide and aluminum oxide having an average particle diameter of 1 μm or less including primary and secondary particles in a resin binder. May be. By providing the transparent elastic layer 171d, the heating roller 17a is configured as a highly elastic soft roller.

The heat ray absorbing layer 171b is the remaining heat ray emitted from a halogen lamp 171g or a xenon lamp (not shown) and absorbed by the light transmitting base 171a and the light transmitting elastic layer 171d. The resin binder is used so as to form a heat ray fixing rotary member capable of absorbing 90% to 100% of heat rays, which is approximately 100% of the heat rays transmitted through the light-transmitting elastic layer 171a and the light-transmitting elastic layer 171d, by the heat ray absorbing layer 171b and capable of rapid heating. A heat ray absorbing member mixed with powder of carbon black, graphite or the like is used, and the heat ray absorbing member is formed on the outer side (outer peripheral surface) of the light-transmitting elastic layer 171d by spraying.

In addition, the PFA (fluorine resin) tube having a thickness of 20 to 100 μm is coated on the outer side (outer peripheral surface) of the heat ray absorbing layer 171b so as to improve the releasability from the toner. Applied, a fluororesin paint applied 20 to 100 μm, and a layer thickness 20 to 500 μm
A mold release layer 171c having a thermal conductivity of ( ^{3 to} 100) × 10 ⁻³ J / cm · s · K is provided (separate type), which is formed by molding silicon rubber or fluororubber of m.

Further, as shown in the cross section in FIG. 3 (b), a heat ray absorbing member mixed with a powder of carbon black, graphite or the like, and a fluororesin (PFA or PTFE) paint or silicon which also serves as a binder and a release agent. The heat ray absorbing layer 1 is used as both the heat ray absorbing layer 171b and the release layer 171c described above with reference to FIG.
A heat ray absorbing layer 171B having releasability by integrally forming 71b and a release layer 171c is formed on the outer side (outer peripheral surface) of the light transmitting elastic layer 171d formed on the outer side (outer peripheral surface) of the light transmitting base 171a. However, it is preferable to form a roll-shaped heat ray fixing rotary member having elasticity.

(Embodiment 1) A fixing device according to Embodiment 1 will be described. FIG. 4 is a plan view showing the main configuration of the fixing device according to the first embodiment. In this embodiment, two types of transfer materials P1 and P2 having different width sizes can be fixed, and the central portion of the heating roller 17a in the axial longitudinal direction and the central portion of the transfer material in the widthwise direction are aligned and sandwiched. Be transported.

As shown in FIG. 4, the fixing device includes a heating roller 17a, a pressure roller 47a, and a halogen lamp 171.
g, temperature sensors TS1a, TS1b, cooling fan 92,
It is composed of a duct 91, duct movable plates 94 and 95, a motor 93, a temperature controller 50A, and the like.

The heating roller 17a is a roller provided with a heat ray absorbing layer for absorbing the heat ray on the outer side of a cylindrical light-transmitting base having a light transmitting property to the heat ray, and a halogen lamp 171g.
Is a halogen lamp provided inside the heating roller 17a. The pressure roller 47a is a roller that rotates while being in pressure contact with the heating roller 17a.

The temperature sensor TS1b is in non-contact with the paper passing portion 17
The surface temperature of the heating roller 17a at the end position of g in the axial direction is measured. Further, the temperature sensor TS1a measures the surface temperature of the heating roller 17a at the central position of the sheet passing portion 17g in the axial longitudinal direction. In addition, 17f in the drawing is a non-sheet passing portion.

The wind of the cooling fan 92 cools the surface of the heating roller 17a. Duct movable plates 94, 9 are provided in the duct 91.
5, the duct 91 and the duct movable plate curved portion 94c, and the duct 91 and the duct movable plate curved portion 95c form two openings 91a, and the width dimension of the opening 91a is movable. In addition, the motor 93 includes duct movable plates 94 and 95.
Drive.

The temperature control unit 50A includes a temperature sensor TS1a,
The cooling region of the heating roller 17a is determined based on the temperature measurement by the TS1b, and the surface temperature of the heating roller 17a is controlled so as not to cause unevenness.

Here, the operation of the fixing device will be described by taking the transfer material P1 as an example. First, the temperature sensors TS1a and TS1b measure the surface temperature of the heating roller 17a. On the basis of the measurement result of the surface temperature, for example, when the temperature of the temperature sensor TS1b is lower than the temperature of the temperature sensor TS1a, the opening width of the opening 91a is reduced and the end of the paper passing portion 17g in the axial direction of the axis. Heating roller 1 to prevent the parts from overcooling
Determine the cooling area of 7a.

When the motor 93 rotates, the female screw 93a rotates and the male screw 93b moves straight. The pin 93c provided on the male screw 93b enters into the long grooves 94b, 95b provided on the duct movable plates 94, 95, and the duct movable plate 94 rotates counterclockwise about the shaft 94a by the movement of the pin 93c. As shown in FIG. 4, the obtained cooling area is moved so as to be cooled. Similarly, by moving the pin 93c,
The duct movable plate 95 rotates clockwise about the shaft 95a and moves so as to cool the obtained cooling region as shown in FIG. On the other hand, the cooling air from the cooling fan 92 is sent from the two openings 91a to prevent the temperature from rising. Here, the unfixed transfer material P1 on which the toner image is formed is passed between the heating roller 17a and the pressure roller 47a, which are maintained at a predetermined temperature, and is heated and pressed to be fixed.

In this embodiment, the opening width of the opening 91a is changed by the duct movable plates 94 and 95, but the present invention is not limited to this. For example, the duct movable plate is slid in the opening width direction. The opening width may be changed by changing the opening width. If the air volume is appropriate, the air volume may be fixed.

Next, another fixing device according to the first embodiment will be described. 5A and 5B are a plan view and a development view of a diaphragm sheet showing a main configuration of another fixing device according to the first embodiment. 4 except for the cooling method is mechanically similar to that of FIG.

As shown in FIG. 5, the fixing device includes a heating roller 17a, a pressure roller 47a, and a halogen lamp 171.
g, temperature sensor TS1 (TS1a, TS1b), cooling fan 92, duct 91, motor 96, throttle sheet 98,
The roller 97 and the temperature control unit 50B are included.

The heating roller 17a is a roller provided with a heat ray absorbing layer for absorbing the heat ray on the outer side of a cylindrical light-transmitting substrate having a light transmitting property with respect to the heat ray. The temperature sensor TS1b measures the surface temperature at the end position of the paper passing portion 17g in the axial longitudinal direction without contact. Further, the temperature sensor TS1a is provided in the paper passing unit 17
heating roller 17a at the central position in the longitudinal direction of g
Measure the surface temperature of.

The air from the cooling fan 92 cools the surface of the heating roller 17a. An opening 91a is formed in the duct 91, and a diaphragm sheet 98 is formed near the opening 91a. The diaphragm sheet 98 is provided with a hole for passing air. The diaphragm sheet 98 is wound around the roller 97 by the rotation of the motor 96 while being given a tension by the spring 99. As shown in FIG. 5B, the aperture sheet 98 has different holes at positions 98a to 98d.

The temperature control unit 50B includes a temperature sensor TS1a,
The cooling region of the heating roller 17a is determined based on the temperature measurement by the TS1b, and the surface temperature of the heating roller 17a is controlled so as not to cause unevenness.

Here, the operation of the fixing device will be described using the transfer material P1 as an example. First, the cooling region of the heating roller 17a is determined based on the temperature measurement by the temperature sensors TS1a and TS1b. For example, when the temperature of the temperature sensor TS1b is higher and lower than that of the temperature sensor TS1a, cooling of this portion is reduced. As shown in FIG. 5B, the aperture sheet 98
The aperture hole provided at the position 98d is selected.

When the motor 96 rotates, the roller 97 rotates and the diaphragm sheet 98 moves, and the hole provided at the position 98d is moved to the position of the heating roller 17a. Cooling fan 92
The cooling air by the air passes through holes provided in the aperture sheet 98 and is sent to the heating roller 17a to prevent the temperature from rising. Here, the unfixed transfer material P1 on which the toner image is formed is the heating roller 17
Paper is passed between a and the pressure roller 47a, and is heated and pressed to be fixed. If the air volume is appropriate, the air volume may be fixed.

As described above, the transfer material can be heat-fixed uniformly by reducing the surface temperature unevenness of the paper passing portion of the heating roller. Particularly, the transfer material can be uniformly heat-fixed in the quick-start type fixing device.

(Second Embodiment) A fixing device according to the second embodiment will be described. In the second embodiment, the heating source control is added to the configuration of the first embodiment. The different parts will be mainly described.

FIG. 6 is a block diagram showing the main structure of the fixing device according to the second embodiment. The fixing device includes temperature sensors TS1a and TS1b, a cooling fan 92, a motor 96,
It is composed of a halogen lamp 171g, a temperature controller 50C and the like.

The temperature controller 50C has a temperature sensor TS1.
a, heating roller 17 based on temperature measurement by TS1b
The cooling area of a (FIG. 5) is determined and controlled so that the surface temperature unevenness of the heating roller does not occur. Further, based on the temperature measurement result, the heat quantity of the halogen lamp 171g of the heating roller is changed to control the temperature to a predetermined temperature. If the air volume is appropriate, the air volume may be fixed.

As described above, the surface temperature unevenness of the paper passing portion of the heating roller can be reduced and the transfer material can be heat-fixed uniformly.
In addition, the surface temperature of the paper passing portion can be accurately adjusted to favorably perform heat fixing. Particularly, the transfer material can be uniformly heat-fixed in the quick-start type fixing device. (Embodiment 3) A fixing device according to Embodiment 3 will be described. FIG. 7 is a plan view showing the main configuration of the fixing device according to the third embodiment. In this embodiment, transfer materials P having different width sizes can be fixed, and the central portion of the heating roller in the axial direction and the central portion of the transfer material in the width direction are pinched and conveyed.

As shown in FIG. 7, the fixing device includes a heating roller 17a, a pressure roller 47a, and a halogen lamp 171.
g, temperature sensors TS2a to TS2f, cooling fan 9
2, nozzles 83a and 83b, linear motors 81a and 81
b, the temperature control unit 50D and the like.

The heating roller 17a is a roller provided with a heat ray absorbing layer for absorbing the heat ray on the outer side of a cylindrical light-transmitting substrate having a light transmitting property to the heat ray, and a halogen lamp 171g.
Is a halogen lamp provided inside the heating roller 17a. The pressure roller 47a is a roller that rotates while being in pressure contact with the heating roller 17a.

Six temperature sensors TS2a to TS2f
Are arranged from the end position in the axial direction of the heating roller 17a to the central position to measure the surface temperature of the heating roller 17a.

The air from the cooling fan 92 cools the surface of the heating roller 17a. There are two flexible nozzles 83a and 83b from the cooling fan 92.
b is movable.

The temperature controller 50D determines the cooling area of the heating roller 17a based on the temperature measurement of the temperature sensors TS2a to TS2f, and moves the nozzles 83a and 83b by the linear motors 81a and 81b to cool the cooling area of the heating roller 17a. Then, control is performed to eliminate temperature unevenness.

The operation of the fixing device will be described below. First, the surface temperature of the heating roller 17a is measured by the temperature sensors TS2a to TS2f. The cooling area of the heating roller is determined based on the measurement result of the surface temperature.

The air volume of the cooling fan 92 is adjusted and sent to the nozzles 83a and 83b, and the linear motors 81a and 81b are supplied.
To move the nozzles 83a and 83b to move the heating roller 1
The cooling area of 7a is cooled.

Here, the unfixed transfer material P on which the toner image is formed is passed between the heating roller 17a and the pressure roller 47a, which are maintained at a predetermined temperature, and is passed through the paper, and is heated and pressed to be fixed. If the air volume is appropriate, the air volume may be fixed.

Next, another fixing device according to the third embodiment will be described. FIG. 8 is a plan view showing the main configuration of another fixing device according to the third embodiment. Note that, except for the cooling method, since it is the same as in FIG. 7 described above, the same parts in terms of mechanism are assigned the same reference numerals, and a partial description thereof is omitted, and different parts are mainly described.

As shown in FIG. 8, the fixing device includes a heating roller 17a, a pressure roller 47a, and a halogen lamp 171.
g, six temperature sensors TS2a to TS2f, a cooling fan 92, a duct 91, throttle mechanisms 85a to 85c, a temperature controller 50E, and the like.

The heating roller 17a is a roller provided with a heat ray absorbing layer for absorbing the heat ray on the outer side of a cylindrical light-transmitting substrate having a light transmitting property with respect to the heat ray.

Six temperature sensors TS2a to TS2f
Are arranged in a non-contact manner in the axial direction of the heating roller 17a from the end position to the central position to measure the surface temperature of the heating roller 17a.

The wind of the cooling fan 92 cools the surface of the heating roller 17a. The duct 91 guides the wind from the cooling fan 92 to the six outlets. Two sets of throttling mechanisms 85a to 85c are provided at each of the outlets, so that the amount of air can be adjusted by shutting off the air or changing the area of the throttling opening.

The temperature control unit 50E determines the cooling region of the heating roller 17a based on the temperature data of the six temperature sensors, selects six discharge ports, determines the aperture areas of the respective throttles, and blows air to the heating roller 17a. Control so that there is no.

The operation of the fixing device will be described. First, the heating rollers 17 are driven by the temperature sensors TS2a to TS2f.
Each surface temperature of a is measured. Based on this measured temperature, the cooling region of the heating roller 17a is determined, six discharge ports are selected, each aperture area is determined, and air is blown to cool. afterwards,
The unfixed transfer material on which the toner image is formed is passed between the heating roller 17a and the pressure roller 47a, which eliminate the temperature unevenness, and is heated and pressed to be fixed. If the air volume is appropriate, the air volume may be fixed.

As described above, it is possible to uniformly heat-fix the transfer material by reducing the surface temperature unevenness of the heating roller. In particular, the transfer material can be made uniform in a quick start type fixing device.

(Fourth Embodiment) A fixing device according to the fourth embodiment will be described. In the fourth embodiment, the heating source control is added to the configuration of the third embodiment. The different parts will be explained.

FIG. 9 is a block diagram showing the main structure of the fixing device according to the fourth embodiment. The fixing device includes temperature sensors TS2a to TS2f, a cooling fan 92, linear motors 81a and 81b, a halogen lamp 171g, a temperature controller 50F, and the like.

The temperature controller 50F determines the cooling region of the heating roller 17a (FIG. 8) based on the temperature measurement result, controls the nozzle by moving the nozzle to cool the heating roller and eliminate the temperature unevenness, and Based on the measurement result of (1), the heat quantity of the halogen lamp 171g provided on the heating roller is changed to a predetermined temperature.

Here, the operation of the fixing device will be described. First, the surface temperature of the heating roller 17a is measured by the temperature sensors TS2a to TS2f. The cooling area of the heating roller is determined based on the measurement result of the surface temperature. Linear motor 8
1a and 81b are moved straight ahead, and cooling air is sent by the cooling fan 92 to cool them. The unfixed transfer material P on which the toner image is formed is passed between a heating roller and a pressure roller, which are maintained at a predetermined temperature, and is heated and pressed to be fixed. If the air volume is appropriate, the air volume may be fixed.

As described above, the surface temperature unevenness of the heating roller can be reduced and the transfer material can be uniformly heat-fixed, and the surface temperature of the paper passing portion can be accurately adjusted to achieve good heat-fixing. In particular, the transfer material can be made uniform in a quick start type fixing device.

In the above-described embodiment, the surface temperature unevenness and the surface temperature accuracy of the heating roller have been described, but the same applies to the pressure roller.

Further, although a plurality of temperature sensors are provided in the above-described embodiment, the same is true even if one temperature sensor is moved in the axial direction of the heating roller or the pressure roller, for example.

Further, in the above-described embodiment, an example in which the fixing device according to the present invention is mounted on the color printer as the image forming device has been shown. However, a monochrome copying machine, a monochrome printer, a facsimile, and other fixing devices for toner images. Needless to say, the present invention can be applied to all image forming apparatuses that require the same as in the above-described embodiment.

Further, as the heating roller, the example in which the heat ray absorbing layer which absorbs the heat ray is provided outside the cylindrical light transmitting body which transmits the heat ray has been described. The same applies to the case where an elastic layer is provided on the outside.

Further, in the above-described embodiment, the type in which the central portion of the heating roller and the central portion in the width direction of the transfer material are sandwiched and conveyed is explained, but one end portion of the heating roller and the transfer material are described. For the type in which one end portion in the width direction is sandwiched and conveyed, the same configuration is obtained by replacing the central portion described in the above-described embodiment with the one end portion.

[0085]

The above-mentioned structure has the following effects.

According to the fixing device of the first aspect, the transfer material can be uniformly heat-fixed by reducing the surface temperature unevenness of the paper passing portion of the heating roller. Particularly, the transfer material can be uniformly heat-fixed in the quick-start type fixing device.

According to the fixing device of the fifth aspect, it is possible to uniformly heat-fix the transfer material by reducing the surface temperature unevenness of the heating roller. Particularly, the transfer material can be uniformly heat-fixed in the quick-start type fixing device.

According to the fixing device of the sixth aspect, the transfer material can be heat-fixed uniformly by reducing the surface temperature unevenness of the paper passing portion of the heating roller, and the surface temperature can be accurately set to a predetermined temperature. Can be heat fixed to. Particularly, the transfer material can be uniformly heat-fixed in the quick-start type fixing device.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a structure of a fixing device of the present invention.

FIG. 3 is an enlarged cross-sectional configuration diagram of the heating roller of FIG.

FIG. 4 is a plan view showing the main configuration of the fixing device according to the first embodiment.

5A and 5B are a plan view and a development view of a diaphragm sheet showing a main part configuration of another fixing device according to the first embodiment.

FIG. 6 is a block diagram showing a main configuration of a fixing device according to a second embodiment.

FIG. 7 is a plan view showing the main configuration of the fixing device according to the third embodiment.

FIG. 8 is a plan view showing a main configuration of another fixing device according to the third embodiment.

FIG. 9 is a block diagram showing a main configuration of a fixing device according to a fourth embodiment.

[Explanation of symbols]

17 Fixing device 17a Heating roller 171g Halogen lamp 47a Pressure roller 50A, 50B, 50C, 50D, 50E, 50F Temperature control parts 81a, 81b Linear motors 83a, 83b Nozzles 85a, 85b, 85c Throttling mechanism 91 Duct 91a Opening 92 Cooling Fan 93 Motors 94, 95 Duct movable plate 98 Drawing sheets P, P1, P2 Transfer materials TS1, TS1a, TS1b, TS2a to TS2f
Temperature sensor

Continued front page    F-term (reference) 2G066 AA01 AC11 AC16 BA31 CA01                 2H033 AA03 AA30 BA27 BA29 BA32                       BB00 CA07 CA44 CA53                 3K058 AA86 BA18 CA23 CA92 CE17                       DA02 DA25 GA06

Claims (7)

[Claims] 1. A fixing device for feeding an unfixed toner image on a transfer material between a heating roller and a pressure roller in pressure contact with the heating roller to heat and press the toner image on the transfer material to fuse the toner image. In, a temperature sensor for measuring the surface temperature at a plurality of positions in the longitudinal direction of the heating roller, based on the temperature measurement result by the temperature sensor, to determine the cooling region of the surface in the longitudinal direction of the heating roller, the cooling region And a cooling unit that cools the fixing device. 2. The plurality of positions are an end position in the axial longitudinal direction of the paper passing portion and a central position in the axial longitudinal direction of the paper passing portion, and the surface is both end portions in the axial longitudinal direction of the heating roller. The surface of a more central part is characterized by the above-mentioned.
The fixing device described in 1. 3. The fixing device according to claim 2, wherein the cooling region on the surface of the heating roller is determined based on the temperature difference between the end position and the central position. 4. The fixing device according to claim 1, 2 or 3, wherein the air volume of the cooling means is variable. 5. The fixing device according to claim 1, 2, 3 or 4, wherein the heat amount of a heating source of the heating roller is changed based on a temperature measurement result of the temperature sensor to bring the heating roller to a predetermined temperature. A fixing device characterized by maintaining control. 6. The cooling means determines a cooling area for cooling the surface of the heating roller from both ends in the longitudinal direction of the heating roller toward the central portion, and moves a nozzle for injecting air to move the surface of the heating roller. 3. A plurality of ventilation openings are provided in the longitudinal direction of the heating roller in the axial direction of the heating roller to cool the heating roller by adjusting the air volume of the ventilation openings.
The fixing device according to 3 or 4. 7. The heating roller has a heat ray absorbing layer for absorbing the heat ray on the outer side of a cylindrical light-transmitting substrate having a light-transmitting property to the heat ray, or on the outer side of a cylindrical thin metal substrate. 7. An elastic layer is provided, and the elastic layer is provided.
The fixing device according to any one of 1.