JP2925335B2 - Fixing device for toner image formation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for forming a toner image in an electrophotographic recording apparatus. It is to eliminate that. Electrophotographic recording apparatuses are widely applied to copiers, laser printers, laser facsimile machines, and the like, and are expected to become more and more popular in the future. In an electrophotographic recording apparatus, an image is formed by repeating each process of charging, exposure, development, transfer, fixing, and cleaning. The present invention focuses on fixing in each process of the electrophotographic recording apparatus as described above. 2. Description of the Related Art In a fixing device of a copying machine or a printer using an electrophotographic method, it is required to reduce power consumption.

For this reason, the conventional heat roll type fixing device has a problem that a rise time is long and heat consumption is large because heat is applied to the heat roll. To solve this problem, a fixing device using a thin film has been proposed. However, there is a demand for lower power consumption and better fixing processing.

[0003]

2. Description of the Related Art FIG. 1 is a schematic view of the prior art. A conventional fixing device uses a thin endless film 4 which is tensioned between two rollers 2 and 3 and a heater 1 as shown in FIG. 1, and runs by rotating a driving roller 2 having a large surface friction coefficient. The recording material 7 on which the toner image 6 has been formed in the developing process, which is a preceding process, is conveyed between the thin film 4 and the pressure roller 5, and the heat of the heater 1 is
To the toner image 6 on the recording material 7 through

[0004]

However, in the conventional fixing device as shown in FIG. 1, since the pressure roller 5 having a circular cross section is used, the thin film 4 and the pressure roller 5 are not connected to each other. The pressure contact portion between them has a small area. Therefore,
Since the recording material 7 can contact only a small area of the press contact portion, the small area of the moist recording material 7 is heated and dried intensively. Wrinkles may occur. In addition, since the contact area is small, sufficient heat must be applied to the recording material 7 despite the short contact time between the heater 1 (thin film 4) and the recording material 7. However, there is a problem that large power consumption is required. The present invention prevents the recording material 7 from becoming wavy or wrinkled,
Another object of the present invention is to provide a fixing device capable of performing a fixing process with low power consumption.

[0005]

According to the present invention, a first endless film tensioned between a first roller and a heater portion is run by the rotation of the first roller, and the first endless film is rotated by the rotation of the first roller. In a fixing device in which a recording material is conveyed while being pressurized with a pressurizing unit and the heat of the heater portion is sent to the toner image on the recording material via the first endless film, a flat contact is made with the pressurizing unit. An area is provided so that the heater section and the pressure section are in flat contact.
And the pressing portion has the planar contact area.
Pressurized parts and one drive and tension
Two rollers, and a tension between the pressing part and the second roller.
And a second endless film
The second endless film and the first endless film.
The recording material is conveyed to and from the
Apply tension to the second endless film with two rollers
A fixing device for forming a toner image is provided , wherein the applied force is smaller than the pressing force of the pressing component .

[0006] In the second invention, in the present invention, a first endless film (4) a fixing device which is characterized in that given a tension by the one first roller which also serves as a drive and tension (17) Is provided.

[0007] In a third aspect, the present invention, a portion in contact with the second endless film of pressurizer (8) (11) is a smooth metal, the second endless off of the pressurized pressure part article (8) < br /> Irumu (11) in contact with the side and fitted with a spring (12) on the opposite side of the pressurized pressure part article (8) of said second endless film (11)
There is provided a pressurizing device characterized by having elasticity so as to be biased to the side. According to a fourth aspect of the present invention, there is provided the pressurizing device according to the present invention, wherein the second endless film (11) is a film of a heat-resistant substance.

[0008]

[0009]

[0010]

According to the first aspect of the invention, the recording material on which the toner image is formed is conveyed by the endless film while the endless film is conveyed by the heater. Heated through. Since the pressing portion (8) has a flat contact area, the time during which the recording material (7) is in contact with the endless film (4) is longer than in the case of linear contact. Therefore, the amount of heat of the heater (1) may be small, and power consumption can be reduced. In addition, the endless film (4)
(8) Wet recording material (7)
Can be prevented from waving or wrinkling when passing between them.

In the second to fifth inventions, the transport mechanism of the first endless film (4) and the second endless film (11) can be simplified.

[0012]

EXAMPLES Hereinafter, with reference to FIG. 2, in connection with the present invention the fixing
The technical contents of the device will be described in detail. In FIG. 2, reference numeral 1 denotes a heater for applying heat to a toner image on a recording material 7, reference numeral 2 denotes a driving roller for driving and driving a thin endless film 4, and reference numeral 3 denotes a tension roller. Reference numeral 7 denotes a recording material that applies slack by applying an appropriate tension, 8 denotes a recording material, and 8 denotes a pressing unit that presses the recording material 7 flat against the heater 1 (that is, the endless film 4). Note that the heater section 1 has a width of about 15 mm in the conveying direction of the recording material 7, for example.

The pressing portion 8 has a metal flat portion having a smooth surface so that the contact area can be increased as compared with the conventional pressing roller 5 (FIG. 1). In the embodiment shown in FIG. 2, a thin endless film 11 driven by a driving roller 9 and given a tension by a tension roller 10 presses the recording material 7 against the heater 1 via the endless film 4 by the pressing unit 8. Have been. Reference numeral 12 denotes a spring for urging the pressing portion 8, that is, the thin endless film 11 toward the heater 1. The pressing unit 8 also has a width of about 15 mm in the conveying direction of the recording material 7, similarly to the heater unit 1. When the same endless films 4 and 11 are driven by the respective drive rollers 2 and 9, the recording material 7 on which the toner image 6 has been formed in the developing process which is the preceding process is sandwiched between the both thin endless films 4 and 11. Move while being moved. As a result, the recording material 7 is heated, and the toner image 6 is transferred to the recording material 7.
Settled on top. At this time, as described above, the contact area between the endless films 4 and 11 is reduced by the conventional pressure roller 5.
By making it larger than that of FIG. 1, the amount of heat necessary for fixing can be given to the toner image 6 even if the amount of heat of the heater 1, that is, the amount of power consumption is reduced. Further, since the contact area is large, even if the recording material 7 before fixing is wet, it is possible to prevent the recording material 7 from becoming wavy or wrinkled.

FIG. 3 shows the structure of the heater section 1. A heater 13, a holder 14 for supporting the heater 13,
The thermistor 15 comprises a thermistor 15 for detecting the temperature of the heater, and a stay 16 for supporting these members. The heater 13 is formed by screen-printing a heating resistor layer on an alumina substrate having a thickness of 1 mm and providing an overcoat layer thereon. The holder 14 is made of a heat-resistant resin so that the heat of the heater 13 does not escape to portions other than the pressure contact portion. Thin endless film 4,
The structure 11 is made of polyimide, which has little dimensional change and high elasticity.

FIG. 4 shows the configuration of an embodiment of the present invention . The drive roller 2 and the tension roller 3 shown in FIG. 2 are replaced by a single roller 17 having a function of providing both drive and tension functions, and the film 4 to which the tension is applied by the heater component 1 and the roller 17 is run. Similarly, FIG.
The drive roller 9 and the tension roller 10 are combined into one roller 18 having both functions of driving and tension, and the film 1 to which the tension is given by the pressing component 8 and the roller 18 is used.
Run 1 In this way, two films 4,
The recording material 7 is conveyed between 11. To apply tension to the films 4 and 11, it is good to urge the drive rollers 17 and 18 themselves in the direction of the arrow with a spring (not shown). Is a pressurized part 8
Is smaller than the spring 12 that biases the spring.

FIG. 5 shows a configuration in which only one roller 18 is provided on the pressure unit 8 side, and the drive roller 2 and the tension roller 3 are separately provided on the heater 1 side in the same manner as in the example of FIG. It is. In contrast to the embodiment of FIG. 5, only the heater 1 side is constituted by a single roller which serves both driving and tension.
The drive roller 9 and the tension roller 11 may be separately provided on the side of the pressurizing section 8 as in the embodiment of FIG.

[0017]

As described above, according to the present invention, the area of the heater portion 1 that comes into flat pressure contact is increased, and heat is applied to the toner layer 6 on the recording material 7 in a wider area at one time than in the prior art. Therefore, low power consumption of the heater and
It is possible to prevent the recording material 7 from becoming wavy, which greatly contributes to the improvement of the performance of the electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a conventional fixing device.

FIG. 2 is a diagram illustrating the principle of a fixing device related to the present invention.

FIG. 3 is a diagram illustrating the principle of a heater component.

4 is an explanatory view showing the actual施例of the present invention.

FIG. 5 is an explanatory view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heater part 2 ... Heater part drive roller 3 ... Heater part tension roller 4 ... Heater part thin film 5 ... Pressure roller 6 ... Toner image 7 ... Recording material 8 ... Pressure part 9 ... Drive of pressure part Roller 10: Tension roller at pressure section 11: Thin film at pressure section 12: Spring 13: Heater 14: Heater holder 15: Thermistor 16: Stay 17, 18: Roller

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-138048 (JP, A) JP-A-2-140781 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 13/20 G03G 15/20

Claims (4)

(57) [Claims] 1. A is traveling by the rotating first endless film given the tension of the first b <br/> over La between the first roller and the heater portion, said first endless film and the pressing In a fixing device which conveys a recording material while applying pressure between the recording medium and the heat of the heater portion to the toner image on the recording material via the first endless film, a flat contact area is provided in the pressing portion. , The heater section and the pressurizing section are formed so as to be in contact with each other in a plane, and the pressurizing section is
A pressurized part having a flat contact area, a drive and tension
One second roller also serving as a
Second endless tensioned between rollers
The second endless film and the film
To transport the recording material to and from the first endless film
And a second endless fill by the second roller.
The force for applying tension to the
A fixing device for forming a toner image, wherein the fixing device is weakened . 2. The fixing device according to claim 1 , wherein the first endless film is also tensioned by a single first roller that also serves as a drive and a tension. 3. The fixing device according to claim 1 , wherein the portion of the pressing component that contacts the second endless film is a smooth metal, and the portion of the pressing component that is in contact with the second endless film is
A fixing device, characterized in that the the pressurized pressure section article is attached to a spring on the side opposite gave elasticity to bias the side in contact with said second endless film to the side in contact. 4. The fixing device according to claim 1 , wherein
A fixing device, characterized in that two error down dress film is a film of refractory material.