JPS62150277A - Fixing device - Google Patents

Abstract

PURPOSE:To change more than approximately 90% of input energy into heat so as to improve the fixing efficiency and make the rising time quicker of a fixing device, by constituting one of a pair of rotating bodies of a radiating member which houses a heat source and radiates infrared rays of >=2mum in wavelength from its surface and providing a coating layer which absorbs infrared rays on the radiating member. CONSTITUTION:When the heating source 132 provided inside a heat roller main body 131 is conducted following the turning on of the main switch of a copying device, temperature of the heating source 132 quickly rises and the source 132 radiates far infrared rays. The radiated far infrared rays are absorbed from the inner wall surface of the roller main body 131 and heat the roller main body 131. The heated roller main body 131 radiates far infrared rays of >=2mum in wavelength from its surface. On the other hand, a coating layer 136 covering the roller main body 131 absorbs the far infrared rays and is heated by the heat conduction from the roller main body 131. Therefore, the toner is melted by the heat conduction from the heat roller 13 heated in such way and fixed on the transfer paper.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a fixing device used in a recording device such as an electrophotographic device, an electrostatic recording device, or a printer. This invention relates to a fixing device that fixes an object to be fixed onto a recording material by passing the fixing object therethrough.

(Background Art) Conventionally, in an electrophotographic device, an object to be fixed on a recording material,
For example, as a fixing device for fixing a single layer of toner onto a recording material, various fixing devices have been devised that employ fixing methods such as heat fixing, solvent fixing, and pressure fixing. Among these fixing methods, a commonly used fixing method is a heat fixing method, and known fixing devices employing this method include, for example, a chamber fixed fixing device, a heated roller fixing device, and a flash fixing device. However, in the chamber fixing device, the recording material having the toner image is heated in a non-contact manner using a sheathed heater such as Red PJ, L/L, to melt the toner made of resin and fix it on the recording material. energy is required, and furthermore, when the recording material jams, the recording material ignites due to heating. In addition, flash fixing devices require large capacitors in order to instantaneously apply high voltage to the flash lamps to cause them to emit light, which increases the size of the device and requires time to charge the capacitors, making it difficult to increase speed. For this reason, in the current electrophotographic apparatus 1, etc., the fixing device has an internal heat source and is in direct contact with the recording material carrying the toner image. The mainstream is a heating roller fixing device that has a fixing roller that fixes the toner image on the recording material and a pressure roller that comes into pressure contact with the fixing roller.However, in this heating roller fixing device, steel or A fixing roller whose surface is coated with silicone rubber or the like is heated from the inside to about 150 to 200 degrees Celsius using a Haloken lamp heater, etc., and the heated fixing roller and a pressure roller are brought into pressure contact with the fixing roller. Since the toner image is fixed by passing the recording material between them, the efficiency of the energy used for fixing is low.In other words, the thermal efficiency of the Heroken lamp heater is The amount of infrared radiation that can be extracted is as low as about 80-85%, and furthermore, as this heat is transferred to the steel or aluminum cylinder, heat escapes from one end of the cylinder.For this reason, heat insulation is applied to the roller end. I'm thinking about it. Sufficient insulation complicates the equipment and increases cost. Therefore, less than 70% of the heat can actually be used for fixing, which lowers energy efficiency.Furthermore, the above-mentioned In the heating roller fixing device, the temperature required for the fixing roller (approximately 150
Is it necessary to raise the temperature of the halogen lamp heater itself to a very high temperature (approx. 200°C)?
), if the temperature control circuit etc. were to fail, the halogen lamp heater would rise abnormally, causing the temperature around the fixing device to rise abnormally, which would ultimately have a serious effect on the entire device. . In addition, during startup, the heat from the core metal heated by the halogen heater can only be transferred to the silicone rubber by thermal conduction, so it takes a lot of time for the surface of the silicone rubber to reach the fixing temperature, and when paper passes Another drawback is that the change in surface temperature becomes large.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional example, and is highly efficient with little loss of thermal energy, and has high safety.
A further object of the present invention is to provide a fixing device that has a quick rise time and less temperature fluctuation.

(Summary of the Invention) That is, the present invention provides a fixing device that fixes an object to be fixed on a recording material by passing the recording material between a pair of rotating bodies that are in pressure contact with each other. One of the rotating bodies is characterized by having a radiating member that has a heat source inside and emits infrared rays with a wavelength of 2 μm or more from its surface, and a coating layer that is provided on the radiating member and absorbs the infrared rays.・) It's from Lum.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 71
FIG. 32 shows an electrophotographic copying apparatus to which the fixing device of the present invention is applied. When a copy button (not shown) is pressed, the photosensitive tram 1 begins to rotate in the direction of the arrow, and the document table 2 on which the document to be copied is placed moves to the Baume position. Photoreceptor I ~ Crumb j: j:
'1 Electricity is uniformly applied by the 3-wheel drive unit 3 (11-).

On the other hand, the document table 2 starts moving from the home position as the photoreceptor tram 1 rotates. The original on the original platen 2 is illuminated by an original illumination lamp 4, and a light image of the original is sequentially exposed to the uniformly charged photoreceptor drum 1 at an exposure position 6 via a lens system 5. As a result, an electrostatic latent image is formed on the photoreceptor drum 1. Then, this electrostatic latent image is developed into a toner image by a developing device 7, and the toner image is transferred to a transfer paper P as a recording material, which is fed by a paper feed roller 8 and a registration roller 9 in synchronization with the leading edge of the toner image. j is transferred by the transfer charger 10.

The transfer paper P onto which the tree image has been transferred is further transported Ii2 by transport rollers I+ and +2 to reach the fixing device F of the present invention. The transfer paper P is sandwiched and conveyed by a pair of rotating bodies including a heat roller 13 (described later) and a pressure roller 14 that is in pressure contact with the heat roller 13, and the toner on the transfer paper P is melted by heat conduction from the heat roller 13, and the toner is The image is fixed on the transfer paper P.

After fixing, the transfer paper P is delivered 4JI onto the tray 16 by the discharge roller 15, and a copy image is obtained. still,
The photosensitive drum I on which the toner image has been transferred is cleaned by a cleaner 1.
The residual toner is removed in step 7, and the photosensitive drum 1 is ready for the next image formation.

Next, the above-described fixing device of the present invention will be described in more detail with reference to FIGS. 1A, 1B, and 3A and 3B.

1A and 1B show a heat roller 13 that emits far infrared rays. The heat roller 13 is solid ((L i20-Na20) ・A crime 203 ・
A mixture of 8Si○2) and clay was made into a kneaded clay, extruded into a cylindrical shape, and bisque fired at 800°C.
, a hollow roller body 131 coated with an upper layer consisting of 2.8% zinc oxide and 6.8% aluminum hydroxide and fired, and a highly heat-resistant support such as a quartz tube inside the roller body 131. The heat generating source 132 consists of a resistance wire such as a nichrome wire wound spirally around the body, or a resistance wire coated with heat-resistant ceramic and rolled up into a cylinder and fired.
Furthermore, the heat roller 13 has a coating layer 136 on the roller body 131. This coating layer 136 is a layer that absorbs the red light L rays emitted from the roller body 131. On the nut layer side, a silicone rubber layer with high far-infrared absorbing ability was used as the ink layer 136. By providing the foam silicone comb layer in this way, the thermal resistance at the contact surface is reduced compared to conventional heating using only heat conduction. In other words, the discontinuous surface of heat conduction due to the minute space between the roller body and the silicone rubber layer is
Since this is compensated for by heat transfer, the rise time becomes faster than in the case of conventional heat conduction only. In addition, as the vH layer 136, silicone rubber alone can sufficiently absorb far infrared rays, but preferably alumina, calcium carbonate, i1 oxide [lead, magnesium oxide, ferrous oxide], which has strong absorption of far infrared rays. It is better to mix fillers such as In addition, in order to prevent the offset phenomenon of 1 to 3, a resin layer with high mold release properties such as Teflon (trade name) is applied to the coating layer 136.
It may be formed as a surface layer on top. It is also possible to use fluororubber for the coating layer.

Heat generation source 132 provided inside the heat roller main body 131
However, when the main switch (not shown) of the copying machine is turned on and electricity is turned on, the heat generating source 132 quickly heats up and emits far-infrared rays. The emitted far-infrared rays are absorbed from the inner wall surface of the roller body 131 and heat the roller body 131. Then, the heated roller main body 131 emits far infrared rays with a wavelength of 2 μm or more from the roller surface. On the other hand, the coating layer 136 provided on the roller body 131 absorbs this far infrared rays and is heated by heat conduction from the roller body. The toner is eluted 1 by heat conduction from the heated heat roller 13 and fixed onto the transfer paper.

The heat roller main body 131 is rotatably supported by the frame of the fixing device JF via a hall bearing 4-J (not shown), etc., and the heat generation source 32 is located on the central i-axis within the roller main body 131. The fixing device F is fixed to the frame body of the fixing device F via a heat insulating insulator 134 so as to be located at the same position. In addition, 135 supplies power to the heat source 132 through the IL phase-J-Xi-Ah noll.
-FIX, +33gto-ra;::A ceramic heat insulating member that covers the AUS.

Here, in order to efficiently heat the heat roller body and emit far infrared rays efficiently, it is necessary to heat the resistance wire such as nichrome wire without making it red-hot, specifically about 700~
It is preferable to maintain the temperature at 800°C. This is because when the resistance wire becomes red hot, it emits light that is not converted into thermal energy with a wavelength of 1 μm or less, which not only reduces the efficiency of generating Joule heat for human power, but also deteriorates the heat absorption efficiency of the ceramic heat roller. This is because you end up doing it. In addition, when using a non-red-hot resistance wire, the heat conversion efficiency is 9
It was 0% or more -42.

Figure 3A shows the relationship between the wavelength of the far infrared rays emitted from the heat generating source 132 mentioned above and the emissivity (the ratio of the intensity of radiation of the heating element to the intensity of thermal radiation of the mold at the same temperature). It is. (This is when the temperature of the heat source +32 is approximately 500°C.) As shown, the heat source 132 has a wavelength of
μm (the emissivity rises rapidly from the standing position,
Emissivity exceeds 07 at maximum weight or large value P, 809
It now shows a heat conversion rate of 6 or more -E, and furthermore, the wavelength
It exhibits a radiation characteristic in which the emissivity approaches 1 when it exceeds μm.

Therefore, considering that the light absorption properties of resins are generally in the long wavelength region of approximately 5 μm or more, this method is particularly effective when fixing objects that are mainly composed of resins, such as toner. .

The roller base 131 of the heat roller 13 may be made of ceramic as described above, or may be made of a thin metal roller whose inner surface is treated with black, coated with a far-infrared emitting substance such as the above-mentioned medicine, and then fired. But it's okay. However, if the heat roller itself is made of a heat-insulating ceramic, even if a bearing such as a metal member is used to directly contact the roller 5ifM portion, heat will not escape from the roller end to the outside. Since this can be prevented, energy loss can be reduced compared to when a thin metal roller is used.

FIG. 4 shows a state in which the heat roller 13 as described above is incorporated into a fixing device. A pressure roller 14 is pressed against the heat roller 13 by a pressure means (not shown). This pressure roller 14 is made of an aluminum cylinder coated with RTV silicone rubber. The surface temperature of the heat roller 13 is detected by the temperature sensor 17, and based on the detection result, the TL flow that is energized to the heat generating source 132 provided inside the heat roller 13 is controlled by a temperature control circuit (not shown). There is. Thereby, the roller itself is maintained at a predetermined temperature.

Further, as shown in the figure, the heat roller 13 is surrounded by a reflective plate 18 made of gold (R) such as aluminum for heat insulation and heat retention.

In FIG. 4, reference numeral 19 indicates an entrance guide for guiding the recording material to the pressure contact portion of the pair of rollers, 20 indicates an ejection guide for guiding the recording material after fixing, and 21 indicates a guide for guiding the recording material around the heat roller 13. Prevents 71" claw release.

(Effects of the Invention) As explained above, according to the present invention, one of the pair of rotating bodies is constituted by a radiation member that has a heat source inside and emits infrared rays with a wavelength of 2 μm or more from the surface; By providing a coating layer that absorbs the infrared rays on the radiating member, it is possible to convert about 90% or more of the human energy into heat, thereby improving the fixing efficiency and speeding up the rise time.

Furthermore, the temperature of both the rotating body and the heat source is between 180℃ and 3℃.
Since the temperature is maintained at 00°C, there is no possibility that the recording material will burn in the event of a jam.

[Brief explanation of drawings]

FIG. 1A is a perspective view of a heat roller showing an embodiment of the fixing device of the present invention, FIG. 18 is a sectional view showing the inside of the heat roller, and FIG. 2 is an electrophotographic copying apparatus to which the fixing device of the present invention can be applied. A schematic sectional view, FIG. 3 is a graph showing the relationship between the wavelength and emissivity of far infrared rays emitted from a heat source provided inside the heat roller, and FIG. 4 is a schematic sectional view showing an embodiment of the fixing device of the present invention. It is. 13---Heat roller 14---One pressure roller + 7---One temperature sensor 18---One reflection plate 131---Heat roller body 132---One heat source 133--- Gosho heating member 134 -- Gosho thermal insulator 135 --- Lead wire + 36 --- Activated layer F ------- Fixing device

Claims (1)

[Claims] (1) In a fixing device that fixes an object to be fixed on a recording material by passing the recording material between a pair of rotating bodies that are in pressure contact with each other, at least one of the rotating bodies has a heat source inside. What is claimed is: 1. A fixing device comprising: a radiating member which emits infrared rays having a wavelength of 2 μm or more from its surface; and a coating layer provided on the radiating member and absorbing the infrared rays.