JPH049989A - Fixing device - Google Patents

Abstract

PURPOSE:To simply and surely prevent a heat resistance endless film from being deviated by constituting the fixing device so that deviating force carrying the film is applied always in the reverse direction against an end part forming a rib. CONSTITUTION:A recording sheet is passed over an inlet guide 13 and sent between the film 2 and a press roller 10, a toner image on the sheet is heated and melted with heat and pressure by a heater 1 and the roller 10 and fixed on the sheet, which is discharged to the outside of the device by a paper discharge roller 15 through a separation guide 14. Since the rib 3 is formed on the end part of one side of the endless film 2 and deviating force at carrying the film is applied always in the reverse direction against the end part forming the rib 3, the deviation of the film can be simply and surely controlled by pressing the rib 3 by a regulating member 16 formed on the inside of the rib 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device used in an image forming apparatus that records a toner image on a recording sheet, such as a copying machine, a laser beam printer, or an electrostatic printer.

[Prior Art] Conventionally, in the fixing device installed in this type of image forming apparatus, many methods using a heat roller have been proposed as a means for fixing the toner image on the recording sheet, but the power consumption is There were disadvantages such as a large amount of heat and a long time required to reach a temperature capable of fixing.

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.

In this fixing device, a heat-resistant film is disposed between a heat-generating body having a linear heat-generating portion and a pressure roller, and a recording sheet carrying an unfixed toner image is heated together with the heat-resistant film. The toner image is passed through a pressure roller, and the heat from the heat-generating portion is transmitted to the unfixed toner image through the heat-resistant film to melt and fix the toner image.

[Problems to be Solved by the Invention] However, in the conventional fixing device using a heat-resistant film, a thin endless film is used as the heat-resistant film, and a roller or the like is used to apply tension to the film as a means for endlessly transporting the film. Due to the drive, the film shifts.

Conventionally, it has been possible to suppress this type of shift during film transport to a certain level by adjusting the pitch between rollers, tension, and the precision of the film's cylindricity, but there is a limit when considering mass production. , it is not a fundamental solution.

Also, if the film is made of a material with a high elastic modulus such as rubber,
Self-centering using a crown-shaped roller is also possible, but
The endless film that can be used in the above fixing method has a small elastic modulus and is very thin, so no effect can be expected.

On the other hand, a method has been proposed in which the film misalignment is detected using an optical sensor and the result is fed back to move the driven roller up and down to keep the film misalignment within a certain range. The device requires a light sensor and a mechanism to move the driven roller up and down.
The disadvantages were that the fixing device was complicated, large, and heavy.

An object of the present invention is to provide a fixing device that can reliably prevent a heat-resistant endless film from shifting with a simple configuration.

[Means and effects for solving the problem] A fixing device that achieves the object of the present invention is provided with ribs at one end of the endless film, and the shifting force during film transport is directed in the opposite direction to the end where the ribs are provided. By having a structure that always works and pressing the rib with a regulating member provided closer to the center of the film than the rib, it is possible to easily and reliably regulate the deviation. Furthermore, by using a member that regulates the ribs as a rotating body that rotates following the ribs, sliding resistance due to deviation regulation can be reduced.

[Example] Example 1 FIG. 1 shows a cross section of a fixing device which is Example 1 of the present invention. In the figure, 1 is a heating body, 2 is a fixing film,
A release layer such as PTFE is coated on one side of a 20 μm thick film made of a heat-resistant resin such as polyimide, polyetherimide, or PES. The total thickness of the film is generally 50μ
The following are preferred. 3 is a rib provided on the outer periphery of one side (front) end of the film. Even if it is integrally molded from the same material as the film, it is possible to attach a rib made of another material with good sliding properties, such as urethane rubber or silicone rubber, afterwards. It may be formed by, for example,

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 has a biasing means 8 (
9), the tension roller 5 is biased in the direction of arrow A through 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. 10 is a pressure roller;
It has a rubber elastic layer made of silicone rubber or the like with good release properties, 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 following the film 2. The heating body 1 is fixed on a stay 2 having a rigidity that can withstand the pressing force via a heat insulating member 11 made of a heat-resistant resin. Also, 13 is the recording sheet human logite, 14 is the separation guide,]
Reference numeral 5 denotes a paper ejection roller consisting of a pair of rollers 15a and 15b.

FIG. 2 is a view of FIG. 1 viewed from the upper right, and reference numeral 16 denotes a regulating member for interfering with the rib 3 and regulating the movement of the film 2 in the right direction in the figure, along the outer periphery of the drive roller 40. rib 3
is installed inside.

The film 2 has the biasing force of the biasing means 8 and 9 such that the biasing force of the biasing means 8 (f, l<the biasing force of the biasing means 9 (f2),
By adjusting the relationship as follows, a biasing force is always applied in the direction of arrow C during transportation.

When the film 2 is conveyed, a shifting force acts on the film 2 in the direction of arrow C, but the ribs 3 collide with the regulating member 16 to be regulated and the shifting is stopped. At this time, it is desirable that at least the surface of the regulating member 16 that slides on the rib 3 is made of a material with good sliding properties, such as polyacetal or fluororesin.

In the above configuration, a recording sheet (not shown) passes over the input logite 13 and is fed between the film 2 and the pressure roller 10, and the toner image on the recording sheet is formed by heat and pressure from the heating body 1 and the pressure roller 10. It is heated and melted and fixed onto the recording sheet, passes through the separation kite 14, and is discharged out of the apparatus by the paper discharge roller 15.

As described above, the rib 3 is provided at one end of the endless film 2, and the shifting force during film transport is always applied in the opposite direction to the end where the rib 3 is provided, and the rib 3 is provided inside the rib 3. By pressing the ribs with the regulating member 16, the shift control can be easily and reliably performed. In the experiment, the rib width,
When urethane rubber ribs of about 1 to 10 mm are adhesively molded onto a film using epoxy adhesive, the biasing force is 10 kg.
We were able to mold a rib that could withstand the above force.

Embodiment 2 FIG. 3 shows a fixing device according to Embodiment 2 of the present invention. As in Example 1, a rib 3 is provided on the outer periphery of one (front) end of the endless fixing film 2, and the fixing film 2 is tensioned by the biasing means 8 (9) via the tension roller bearing 6 (7). Tension is applied by urging the roller 5 in the direction of arrow A, and the drive roller 4 conveys it in the direction of arrow B.

FIG. 4 is a view of FIG. 3 viewed from the upper right, and in the figure, 18 is a regulating member which is a rotary body that rotates driven by the inner surface of the rib 3, and 17 is a regulating support plate that pivotally supports the regulating member 18. can be,
The regulating member 18 and the regulating support plate 17 are installed inside the rib 3 along the outer periphery of the drive roller 4 .

The film 2 is constructed so that a biasing force is always exerted in the direction of the arrow C when the film is transported by adjusting the parallelism and inclination of the rollers 4 and 5 or the urging force of the urging means 8.9. However, if it hits the rib 3 or the regulating member 18,
Since the regulating member 18 regulates the inner surface of the rib 3 while rotating in a driven manner, the sliding resistance is reduced and the shift can be stopped without applying excessive force to the rib. At this time, at least the surface of the regulating support plate 17 on which the regulating member 18 slides and rotates is made of a material such as fluororesin with good sliding properties, and the regulating member 18 is made of a resin with good sliding properties such as iron. Preferably, it is a metal material.

As described above, the ribs 3 are provided at one end of the endless film 20, and the shifting force during film transport is always applied in the opposite direction to the end where the ribs 3 are provided. By pressing the rib with the regulating member 18, which is a rotating body that rotates as a result of the rotation, it is possible to reduce the sliding resistance with the rib, and to easily and reliably control the deviation without applying excessive force to the rib. I can do things. In addition, it is possible to reduce the risk of excessive force being applied to the ribs, wear of the ribs, and peeling of the adhesive when the ribs are adhesively molded, thereby greatly improving durability.

Embodiment 3 FIG. 5 shows a fixing device according to Embodiment 3 of the present invention. The fixing film 20 of this embodiment has a stepped rib 21 on the outer periphery of one side (front). The fixing film 20 is applied to the tension roller bearing 6 (7) by the biasing means 8 (9).
, tension is applied by urging the tension roller 5 in the direction of arrow A, and the sheet is conveyed in the direction of arrow B by the drive roller 4.

Figure 6 is a view of Figure 5 viewed from the upper right, and Figure 7 is
FIG. 3 is an enlarged view of a cross section of a regulating portion. In the figure, 22 is the rib 2
A regulating member which is a rotating body that rotates driven by the inner surface of the upper stage of the first stage, 23 is a regulating support plate that pivotally supports the regulating member 22,
The regulating member 22 and the regulating support plate 23 are installed inside the rib 21 along the outer periphery of the drive roller 4 .

The film 20 is constructed so that a biasing force is always exerted in the direction of arrow C when the film is transported by adjusting the parallelism and inclination of the rollers 4.5 or the urging force of the urging means 8.9. However, when the rib 21 collides with the regulating member 22, the regulating member 22 regulates the inner surface of the upper stage of the rib 21 while rotating in a driven manner, so the sliding resistance is small and no excessive force is applied to the rib 21. Stopping can be stopped. At this time, the rib 21 applies a regulating force of the same magnitude as the biasing force to the regulating member 2.
It is received from 2 in the direction of the arrow.

FIG. 8 is an enlarged view of the cross section of the regulating portion of the fixing device shown in Example 2. Again, since the ribs 3 receive the regulating force in the direction of the arrow, in particular, the ribs 3 are bonded to the film 2. If molded, there is a possibility that the film 2 and the rib 3 will be damaged from the regulating side corner G due to durability or the like.

On the other hand, the ribs 21 in Example 3 are subjected to the regulating force at the upper part of the stage, so that the film 20 and the ribs 21 are not damaged from the regulating side corner F. In this case, the regulating force is likely to affect the corner E of the step of the rib 21, but by increasing the strength of the lip 21 itself by adding a radius to the E part, the strength of the film and the rib as a whole can be increased. Improving dramatically. Further, in this embodiment, since the contact area between the rib and the film can be increased without increasing the longitudinal dimension of the fixing device, the strength of the film and the rib can be further improved.

In this example, the strength of the rib and film can be improved by providing a step in the rib and regulating the side surface of the upper stage, and is particularly effective when molding by bonding the rib to the film. be.

Embodiment 4 FIG. 9 is an enlarged cross-sectional view of a rib regulating portion of a fixing device according to Embodiment 4 of the present invention. In the figure, as the side surface on the regulation side approaches the outer periphery of one end of the film 25,
Ribs 26 are provided which are inclined in the direction in which the rib width becomes wider.

A regulating member 28 is a rotating body that rotates along the slope of the rib 26. Reference numeral 27 denotes a regulating support plate that pivotally supports the regulating member 28 , and the regulating member 28 and the regulating support plate 27 are arranged inside the rib 26 provided on the film 25 .

When the regulating member 28 is driven to rotate and regulates the inner slope of the rib 26, the rib 26 receives a regulating force from the regulating member 28 in the direction H, but the regulating force is decomposed into directions H0 and H7. As a result, the rib 26 is always subjected to force in the direction of %H2, and since the film 25 is firmly supported on the back side by the drive roller 4, breakage occurs from the corner I between the rib 26 and the film 25. Never. Therefore,
The strength and durability of the ribs can be improved.

As described above, the strength and durability of the rib can be improved by making the rib inclined in such a direction that the width of the rib increases as the side surface on the regulating side approaches the film. This embodiment is also particularly effective when molding ribs by adhering them to a film.

[Effects of the Invention] As explained above, according to the present invention, ribs are provided at one end of the endless film, and the shifting force during film transport is always applied in the opposite direction to the end where the ribs are provided. By pressing the rib with the regulating member, it is possible to easily and reliably regulate the deviation.

In addition, by using a rotating body that rotates following the rib as the member that restricts the rib, it is possible to reduce the sliding resistance caused by the deviation restriction.

Furthermore, by providing a structure in which the ribs are provided with steps and the upper portions are restricted, the strength and durability of the ribs can be improved.

Further, by forming at least the side surface of the rib on the regulating side into a rib shape that is inclined in a direction in which the rib width becomes wider as it approaches the film, it is effective to improve the strength and durability of the rib.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a fixing device according to a first embodiment of the present invention, FIG. 2 is a top right diagram of FIG. , FIG. 5 is a sectional view of the fixing device of Example 3, FIG. 6 is an upper right view of FIG. FIG. 9 is an enlarged view of a cross section of the fixing device with rib restriction according to the second embodiment, and FIG. 9 is an enlarged view of a cross section of the fixing device with rib restriction according to the fourth embodiment. DESCRIPTION OF SYMBOLS 1... Heating body, 2, 20.25... Fixing film, 3.21.26... Rib, 4... Drive roller, 5... Tension roller, 6.7... Tension roller bearing, 8.9... urging means, 10... pressure roller, 11...
... heat insulation member, 12 ... stay, 13 ... human logite, 14 ... separation guide, 15 ... paper ejection roller, 16.18.22.28 ... deviation regulating member, 17.2
3.27...Regulation support plate. 4 other people

Claims (1)

[Scope of Claims] 1. A fixing device that heats and melts an unfixed toner image carried on a recording sheet via a heat-resistant endless film to fix it, wherein a rib is provided at one end of the endless film, and When the endless film is conveyed, a biasing force is applied in a direction opposite to the end portion having the ribs,
A fixing device characterized in that a member that regulates the biasing force by interfering with the rib is provided closer to the center of the film than the rib. 2. The fixing device according to claim 1, wherein the rib is provided on the outer peripheral surface of the film. 3. The fixing device according to claim 1, wherein the member for regulating the shifting force is a rotating body that rotates following the rib. 4. The fixing device according to claim 1, 2 or 3, wherein the rib is stepped. 5. The fixing device according to claim 1, 2 or 3, wherein at least a side surface of the rib on the regulating side is inclined in a direction in which the width of the rib increases as it approaches the film.