JPH0325477A - Fixing device - Google Patents

Abstract

PURPOSE:To improve the strength and durability of a heat-resistant endless film by providing a rib at least on one side of the endless film. CONSTITUTION:A fixing film 2 being the heat-resistant endless film is stretched between a driving roller 4 and a tension roller 5, and forms a film carrying path together with a heater 1. A transfer sheet is fed between the film 2 and a pressure roller 10, and a toner image on the transfer sheet is heated and fused by the heat of the heater 1 and the pressure of the pressure roller 10, and fixed on the transfer sheet. The rib 3 is provided on one side of the heat- resistant endless film 2. Consequently, the entire strength of the film 2 made thin can be enhanced and durability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device used in image forming apparatuses such as copying machines, LBPs, and electrostatic printers. [Prior Art] Conventionally, a method using a heat roller has been proposed as a means of fixing a toner image on recording paper, but this consumes a lot of power and takes a long time to reach a temperature that can be fixed. There were other drawbacks.

On the other hand, a fixing method using a heat-resistant film that improves the above-mentioned drawbacks has been proposed in Japanese Patent Laid-Open No. 63-313182.

[Problems to be Solved by the Invention] However, the proposed fixing device uses a thin endless film, and as a means of transporting the film, tension is applied to the film using rollers, etc., which causes the film to shift. Put it away.

Further, since the film is very thin and heat is applied under tension for driving, the film is prone to creep and deformation due to durability.

[Means for Solving the Problems] The present invention, which solves the above problems, is a fixing device that heats and melts a toner image through a heat-resistant endless film to fix the toner image. It is characterized by having.

[Embodiment of the Invention] FIG. 1 shows a cross section of a fixing device according to a first embodiment of the invention. In the figure, 1 is a heating element, 2 is a fixing film, and one side of a 20 μm thick film made of a heat-resistant resin such as polyimide, polyetherimide, or PES is coated with a release layer such as PTFE. The total thickness of the film is generally 50
It is preferably less than μ. 3 is a rib provided on the outer periphery of one side (front) end of the film, and it may be integrally molded from the same material as the film, or it may be formed with a rib made of a different material with good sliding properties later by adhesion, etc. do not have.

The fixing film 2 is stretched between a drive roller 4 and a tension roller 5, and together with the heating element 1, forms a film transport path. The fixing film 2 is biased by a biasing means 8 (9
), the tension roller 5 is biased in the direction of arrow A via the tension roller bearing 6 (7), thereby applying tension and being conveyed in the direction of arrow B by the drive roller 4. Here, in order to reliably transport the film 2, the drive roller 4 has a coating layer of Si rubber or the like provided on the surface of a core metal such as iron. A pressure roller 10 has a rubber elastic layer made of silicone rubber or the like having good shape, and presses the film 2 against the heating body 1 with the force necessary for fixing. Further, both ends of the pressure roller 10 are supported by bearings (not shown) so as to rotate along with the film 2. The heating element 1 is fixed on a steel plate 12 having a rigidity sufficient to withstand the pressing force via a heat insulating member 1l made of heat-resistant resin. Also 13
1 is a population guide, 14 is a separation guide, and 15 is a paper discharge roller.

FIG. 2 is a view of FIG. 1 from the upper right, and FIG. 7 is a view of FIG. There is. When the film 2 shifts in the direction of arrow C, the lever 17 rotates and turns the sensor ON and OFF.
It is configured to be FF. By turning on and off the solenoids 18, 19 and adjusting the biasing force of the biasing means 8.9 based on the signals from this sensor, the direction of shift can be changed and shift control can be performed reliably.

In the above configuration, the transfer paper (not shown) passes over the artificial guide and is fed between the film 2 and the pressure roller 1o,
The 1/toner image on the transfer paper is heated and melted by the heat and pressure from the heating body 1 and the pressure roller 10, and is fixed on the transfer paper, and the transfer paper passes through the separation guide 14 without wrinkles or jams, and is transferred to the tJF paper. It is discharged out of the apparatus by rollers 15. Here, the film is very thin and is heated under the tension necessary for driving.
Since the strength of the entire film is increased by the ribs 3 at the ends, deformation of the film due to durability does not occur. or,
The sensor detection lever 17 constantly rubs against the rib 3, but since the rib itself is strong, there is no problem in terms of durability, and the shift control can be performed reliably.

Furthermore, the optical sensor 16 may deteriorate due to heat.

In this embodiment, since the optical sensor 16 can be arranged larger than the heat generating area in the film generatrix direction, it is better that the optical sensor 16 is not subject to thermal deterioration.

As described above, this embodiment is particularly effective when using an optical sensor as the sensor.

As described above, by providing ribs on one end of the heat-resistant endless film, the strength of the entire film, which is extremely thin, can be increased. Furthermore, if the sensor detection lever is brought into contact with the rib and actuated to control the deviation, the durability will be improved and the operation can be performed reliably.

FIG. 3 shows a fixing device according to a second embodiment of the invention.

Fixing film 2 is also a thin endless film.
Ribs 22 and 23 are provided on the outer periphery of both ends of 1. The fixing film 2l is conveyed in the direction of arrow B by the drive roller 4 which is given tension by urging the tension roller 5 in the direction of arrow A by a biasing means (not shown).

FIG. 4 is a view of FIG. 3 viewed from the upper right, and shows the ribs 22,
Regulating members 24 and 25 for regulating each of the ribs 23 are installed along the outer periphery of the drive roller 4 inside the ribs 22 and 23, respectively.

The fixing film 21 consists of a base layer made of polyimide and a paste-shaped layer made of fluororesin provided on the polyimide.

The ribs 22 and 23 are formed integrally with the base layer and are provided with a release layer extending at least to the inner surface on which the regulating members 24 and 25 slide.

child. Therefore, it has excellent sliding properties and does not interfere with the movement of the film.

According to this embodiment, deviation occurs in the film 21, and arrow D
Even if the film shifts in the direction of
It collides with and is regulated and stops moving. Conversely, when the film shifts in the direction of E, the lip 23 is regulated to 25 and the shift stops there. At this time, the regulating member 24.25
It is desirable that at least the surface that slides on the ribs is made of a material such as fluororesin that has good sliding properties.

By regulating the ribs at both ends of the film as described above, it is possible to easily and reliably control the deviation.

Next, FIG. 5 shows a third embodiment of the present invention, in which a rib 32 is provided on the inner periphery of one end of a fixing film 31. FIG. 6 is a view of FIG. 5 viewed from the upper right, and shows the film 31.
is given tension by urging the tension roller 5 in the direction of the arrow A by the urging means 8 and 9, and is conveyed in the direction of the arrow B by the drive roller 4.

The film 2 is moved by the inclination of the rollers 4.5 or the biasing means 8.
By adjusting the biasing force by 9, etc., the structure is such that a biasing force always acts in the direction of arrow F during conveyance. or,
The rib 32 is connected to the drive roller 4, tension roller 5. It is received by the end face of the heat insulating member 11 to prevent the film from shifting in the direction F.

When transporting the film 3l, a biasing force acts in the direction of the arrow F, but the rib 32 on the inner circumference of one end of the film 31 is moved by the rollers 4.
, 5. By adopting a configuration in which the heat insulating member 11 is hooked onto each end face, it is possible to easily and reliably prevent the heat insulating member from shifting.

Furthermore, the number of parts in the above structure is small, and the ease of assembly is greatly improved.

Also, in the above structure, the case where the ribs are provided on the inner periphery of the film has been explained, but the invention is not limited to this, and in the case where the ribs are provided on the outer periphery, the same configuration can be made by adding a regulating member. Can be done.

[Effects of the Invention] As explained above, by providing ribs in the circumferential direction at least on one end of the heat-resistant endless film, the strength of the endless film can be greatly improved. Furthermore, even when an actuator such as a sensor detection lever is brought into contact with the rib to detect deviation during film drive, durability is improved by increasing the strength of the edge of the film due to the rib. Further, by directly regulating the above-mentioned rip, it is possible to prevent the film from shifting during driving.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a fixing device embodying the present invention, and Fig. 2 is a cross-sectional view of a fuser embodying the present invention.
FIG. 3 is a sectional view of the fixing device according to the second embodiment of the present invention; FIG. 4 is a top right view of the embodiment shown in FIG. 3; 6 is a top right view of the embodiment in FIG. 5, and FIG. 7 is a left view of the embodiment in FIG. 1. 1 is a heater, 2, 21.31 is a fixing endless film, 3, 22, 23.32 is a lip provided at the edge of the film, 4 is a driving roller, 5 is a tension roller for applying tension to the film 2, 6.7 is a tension roller bearing, 8.9 is a biasing means, 1 O is a pressure roller, l 1 is a heat insulating member, and 12 is a stay.

Claims (3)

[Claims] (1) A fixing device that fixes a toner image by heating and melting it through a heat-resistant endless film, wherein the endless film has a rib on at least one end. (2) The endless film has a release layer on the surface layer, and the device further includes a regulating member that slides on the film in order to regulate the deviation of the film, and the release layer extends up to the sliding surface of the rib. 2. The fixing device according to claim 1, wherein the fixing device is provided in an extended manner. (3) The fixing device according to claim 1, further comprising a detection sensor for detecting film shift outside the rib, and the rib actuating an actuator that operates the sensor.