JP2542090B2 - Fixing device and fixing film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fixing device used in an image forming apparatus such as a copying machine or an electrophotographic printer.

[Prior Art] Conventionally, as means for fixing the toner image on the recording paper,
Although one using a heat roller has been proposed, it has drawbacks such as high power consumption and a long time to reach a fixing temperature.

On the other hand, a fixing method using a heat-resistant film that alleviates the above-mentioned drawbacks has been proposed by JP-A-63-313182. In this proposed fixing device, an insulating thin film endless film is used, and the film is laid over a roller and a heating body to form a film conveying path.

Further, the applicant previously proposed in Japanese Patent Application No. 63-12069 that a release layer is provided as a film of such a fixing device on the side of the heat-resistant resin which comes into contact with the toner.

[Problems Solved by the Invention] However, in the above-mentioned conventional example, since the release layer is coated on the entire surface, there are the following drawbacks.

1) Since the film is a thin film, when the release layer has a low resistance, if other members such as the driving roller and the driven roller are conductive, there is a possibility of leakage depending on the charging of the film.

2) Since the film has a coat layer with good releasability, the pressure roller may slip due to insufficient frictional force depending on the surface property of the pressure roller, and in extreme cases, it will not rotate. Further, if the pressure roller is driven and the film is driven, the film may slip or stop depending on the tension of the film.

3) Since the film has a coat layer with good releasability, when a rib for suppressing the deviation of the film is formed at the end of the film, the adhesive force is extremely reduced.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a heating body, one surface of which slides on the heating body, and the other surface of which is provided with a release layer and is in contact with an unfixed image. In a fixing device having an endless film that moves together, and fixing an unfixed image on a recording material by heat from the heating body via the film, the release layer is in a circumferential direction of the film. It is provided except for the end regions in the direction orthogonal to each other, and a rib for controlling the deviation of the film is bonded to the end regions where the release layer is not provided. is there.

The present invention also provides an endless fixing film having a release layer on the surface thereof, wherein the release layer is provided excluding an end region in a direction orthogonal to the circumferential direction of the film, and the release layer is provided. A rib for controlling the deviation of the film is adhered to the non-opened end area.

[Embodiment] FIG. 1 is a sectional view of a fixing device according to a first embodiment of the present invention. Here, 1 is a low-heat-capacity linear heating element, which is, for example, an alumina substrate having a thickness of 1.0 mm, a width of 10 mm, and a longitudinal length of 240 mm coated with a resistance material in a width of 1.0 mm. ing. The heating body 1 is fixed by a heat insulating member (holder) 11 made of a heat resistant resin and a support 12 having rigidity. Energization is, for example, 100 VDC cycle
A pulse having a pulse shape of 20 msec, which is controlled by the temperature detecting element 20 and corresponds to a desired temperature and energy emission amount, is given by changing its pulse width. The approximate pulse width is 0.5 to 5 msec. The fixing film 2 moves in the direction of arrow B in the figure by coming into contact with the heating body 1 whose energy temperature is controlled in this way. This film is made of a heat-resistant resin such as polyimide, polyetherimide, PES, etc., which is coated with a release layer such as PTFE on the outer surface of a thin endless film with a thickness of about 20 μm, which is made conductive by dispersing carbon etc. A distinction is made between the part 2a and the uncoated end 2b. Here, the uncoated end portion 2b of the film is a non-paper passing area, and is provided with a sufficient distance from the paper passing portion so as not to affect the offset. Further, it is generally desirable that the total thickness of the film is 50 μm or less. Reference numeral 3 denotes a rib provided at the location of the film 2b, to which a rib made of a material different from that of the film 2 such as rubber is bonded later. Since the film 2b is not coated with the release layer, the adhesiveness with the rib 3 is very good.

The fixing film 2 is stretched between a driving roller 4 and a driven roller 5 and forms a film transport path together with the heating body 1. The fixing film 2 has a biasing means 8
By (9), the driven roller is urged in the direction of arrow A via the driven roller bearing 6 (7) to be given a tension, and is conveyed by the drive roller 4 in the direction of arrow B. Here, the drive roller 4 has a rubber elasticity with good releasability such as silicon rubber on the back surface of a cored bar made of iron or the like in order to surely convey the film 2, and the force required for fixing the film 2
To the heating element 1. Further, the heating roller 10 is
Both ends are supported by bearings (not shown) so as to rotate following the film 2, and the film 2 is supported at a total pressure of 4 to 7 kg.
The heating element is pressed through the pressure roller and pressed against the film to rotate.
Further, 13 is an inlet guide, 14 is a separation guide, and 15 is a paper discharge roller.

2 is a view of FIG. 1 seen from the upper right side, and FIG. 3 is a view of the FIG. 1 seen from the right side, and FIG.
The lever 17, which is the actuator of the sensor 16, is in contact. When the film 2 shifts and the film shifts in the direction of the arrow C, the lever 17 rotates and the sensor is turned on and off. By controlling the solenoids 18 and 19 to be turned on and off respectively by the signals of this sensor and adjusting the biasing force by the biasing means 8 and 9, the shift direction can be changed and the shift control can be reliably performed.

When fixing is performed, the transfer material 22 with the toner 21 is conveyed from an image forming apparatus (not shown). A film 2 which is rotated by a driving roller 4 when the heating body 1 is energized.
Is heated and kept at a predetermined temperature. In this state, the transfer material 22 having the unfixed toner 21 thereon is heated, pressurized and conveyed by the heating body 1, the film 2 and the pressure roller 10 to obtain a fixed image. The transfer material, which has become a fixed image, is discharged to the outside of the apparatus by the paper discharge roller 15 via the separation guide 14. Here, the detection lever 17 always slides on the rib 3, but since the rib itself has high strength and is adhered to the film end 2b which is not coated with the release layer,
The adhesive strength was very strong, there was no problem with the influence of heat and durability, and the deviation control could be performed reliably.

As the rib material, a material having both heat resistance and elasticity, such as silicone rubber, urethane rubber, or chlorosulfonated polyethylene, was used. As the adhesive, an epoxy, cyanoacrylate, silicone, rubber or other adhesive having heat resistance and elasticity to some extent was used.

FIG. 4 shows another embodiment of the present invention. That is, at both ends of the film 2, a portion without a release layer subjected to conductive treatment is provided.
This is the case when 2b is present.

In this case, a leak to the driving roller 4, the driven roller 7, the heating body 1, and the side sheet metal (not shown) due to the charging of the coating portion caused by the pressure roller rotation of the fixing roller or the transfer material and the film causes the uncoated portion. Could be prevented due to the presence of 2b.

FIG. 5 shows still another embodiment of the present invention. That is, the pressure roller drive gears 23a and 23b are provided, the pressure roller 10 is driven, and the film 2 is kept in tension by the two driven rollers 5a and 5b and the heating body 1. In this case, film 2
Since the non-coated portion 2b having a large friction coefficient is in contact with the pressure roller, no slippage of the film 2 was observed and good film rotation and transfer material transfer were obtained.

FIG. 6 shows still another embodiment. That is, a separation roller 24 is newly provided, the film 2 and the transfer material 23 are separated by this roller, and the separation can be performed after cooling. In this system, the driven roller (separation roller) further expands, but good results were obtained for problems such as deviation control and leakage.

[Effects of the Invention] As described above, by preventing the release layer from being provided on at least one end of the film, which is the non-sheet-passing part of the heat-resistant endless film, leakage from the end of the film is prevented, and the film is further prevented. It has the effect of increasing the adhesiveness and the coefficient of friction at the ends of the.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a fixing device according to an embodiment of the present invention, FIG. 2 is a top view of the fixing device of FIG. 1 seen from the upper right, and FIG. 3 is a right lateral view of the embodiment of FIG. FIG. 4 is a top view of another embodiment of the present invention seen from the upper right, and FIGS. 5 and 6 are sectional views of still another embodiment of the present invention. 1 …… Heating body 2 …… Film 3 …… Rib 4 …… Drive roller 5 …… Driven roller 6,7 …… Driven roller bearing 8,9 …… Biasing means 10 …… Pressure roller

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-59-168467 (JP, A) JP-A-58-220165 (JP, A) JP-A-58-217975 (JP, A) JP-A-58- 214180 (JP, A) JP-A-63-313182 (JP, A) JP-A-1-187582 (JP, A) Actual exploitation Sho-57-70244 (JP, U)

Claims (2)

(57) [Claims] 1. A heating body, and an endless film, one surface of which slides on the heating body, and the other surface of which includes a release layer and which moves together in contact with an unfixed image. In a fixing device for fixing an unfixed image on a recording material by heat from the heating body through a film, the release layer is provided except for an end region in a direction orthogonal to the circumferential direction of the film. The fixing device is characterized in that a rib for controlling the deviation of the film is adhered to an end region where the release layer is not provided. 2. An endless fixing film having a release layer on the surface thereof, wherein the release layer is provided except for an end region in a direction orthogonal to the circumferential direction of the film, and the release layer is provided. The fixing film is characterized in that ribs for restricting the deviation of the film are adhered to the non-edge portion of the fixing film.