JPH0444081A - image heating device - Google Patents

Abstract

PURPOSE:To stably and easily control the displacement of a film with simple means constitution by employing relation constitution wherein a displacing force operates on one side throughout film driving and providing a member which restricts the movement by receiving of the displacement-side film end part. CONSTITUTION:The pressing force f27 of a right-side spring 27 on a driving side between springs 26 and 27 is set larger than the pressing force f26 of the right spring 26 as a driven side (f27>f26), and then when the film 21 is driven, a displacing force operates on the film 21 in the right direction R of the film width along the lengthwise direction of the stay 13 at all times. Then only the end part of the film 21 on the displacement side R is restrained by the right-side flange member 27 as the restriction member. Consequently, the displacement control over the film can stably and easily be performed to obtain an excellent fixed image stably at all times.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a heat-resistant PL that is brought into pressure contact with a heating body and driven to move.
A recording material that supports a visual image is introduced onto the side of the film opposite to the heating element side, and the recording material that supports the visual image is brought into close contact with the film.By passing the heating element together with the film, the heat of the heating element is introduced into the recording material through the film. The present invention relates to a heating device that uses a heating method (film heating method).

This device is an image heating fixing device in an image forming apparatus such as an electronic copying machine, a printer, or a fax machine, that is, an electric r
A recording material (transfer material sheet, electrofax sheet,
An unfixed toner image corresponding to the desired image information, formed by an indirect (transfer) method or a direct method on the surface of an electrostatic recording sheet, printing paper, etc., is permanently attached to the surface of the recording material carrying the image. It can be used as an image heat fixing device that heats and fixes a fixed image.

Furthermore, it can be used, for example, in a device that heats a recording material carrying an image to modify its surface properties (to make it glossy), and in a device that performs temporary adhesion treatment.

(Background Art) Conventionally, for example, a heating device for a recording medium for heat-fixing an image uses a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer and in pressure contact with the heating roller. A heated roller system is often used, which heats the recording material while nipping and conveying it.

In addition, various other methods are known, such as a flash heating method, an oven heating method, a hot plate heating method, a belt heating method, and a high frequency heating method.

On the other hand, the present applicant has disclosed, for example, in Japanese Unexamined Patent Application Publication No. 63-313182, a fixedly supported heating body (hereinafter referred to as a heater), a heat-resistant film that is conveyed (moving and driven) while being in pressure contact with the heater. , has a pressure member that brings the recording material into close contact with the heater through the film, and by applying heat from the heater to the recording material through the film, the unfixed image formed and carried on the surface of the recording material is transferred to the recording material. We have proposed a system and configuration for heat fixing on Wi, and have already put it into practical use.

More specifically, a thin heat-resistant film (or Sea 1~
), a means for moving the film, and a heater disposed with the film inside and fixedly supported on one side thereof;
A pressure member is disposed on the other surface side facing the heater and brings the image-bearing surface of the recording material on which the image is to be fixed into close contact with the heater through the film, and the film is at least fixed when the image is fixed. When the recording material to be image-fixed is conveyed and introduced between the film and the pressure member, it is approximately concave in the forward direction.
By moving the recording material at a high speed and passing through a nip portion as a fixing portion formed by pressing a heater and a pressure member with the traveling film sandwiched therebetween, the image-bearing surface of the recording material is transferred through the family film. Heat the heater and apply thermal energy to the visible image (unfixed toner image)! This is a heating means/device which basically separates the film and recording material after passing through the fixing section by softening and melting the recording material at a dividing point.

This kind of film heating type equipment uses a heating element with a fast temperature rise and a thin film, so it is possible to shorten wait time (quick start) and solve various drawbacks of conventional equipment. It has the following advantages and is effective.

FIG. 12 shows a schematic configuration of an example of this type of image heat fixing device using an endless film as the heat-resistant film.

Reference numeral 51 denotes an endless belt-shaped heat-resistant film (hereinafter referred to as a fixing film or film), which includes a driving roller 52 on the left side, a driven roller 53 on the right side, and is arranged below between the driving roller 52 and the driven roller 53. The low heat capacity linear heating body 54 is suspended between the three members 52, 53, and 54 that are parallel to each other.

The fixing film 51 rotates clockwise at a predetermined circumferential speed as the drive roller 52 rotates clockwise, that is, it fixes the heated material carrying on its upper surface an unfixed toner image Ta that is conveyed from an image forming section (not shown). The recording sheet P is rotated at a conveyance speed (process speed) of each recording sheet P and a substantially concave circumferential speed.

55 is a pressure roller as a pressure section side, which biases (not shown) against the lower surface of the heating body 54 by sandwiching the first row side film portion of the endless bell-shaped fixing film 51. The Mt4 sheet P
Rotates forward and counterclockwise in the transport direction.

The heating body 54 is a low heat capacity linear heating body whose length is in the direction (width direction of the film) that intersects the moving direction of the film 510 surface, and includes a heater substrate (base) 56, a current-carrying heating resistor (heating element) 57, It consists of a surface protection layer 58, a temperature measuring element 59, etc., and is fixedly supported by being attached to a support body 61 via a heat insulating material 60.

The recording material sheets 1 to P carrying an unfixed toner image Ta conveyed from an image forming section (not shown) on the "-" side are guided by a guide 62.
The pressure contact portion N between the heating body 54 and the pressure roller 55 is guided by
The unfixed toner image portion enters between the fixing film 51 and the pressure roller 55 of the fixing film 51 which is being rotated in the same direction at the same speed as the conveyance speed of the recording material sheet P.
°The heating element 5 is in close contact with the film and overlapped with the film.
4 and the pressure roller 55 pass through the mutual pressure contact portion N.

The heating element 54 is heated with electricity at a predetermined timing, and the thermal energy on the heating element 54 side is transmitted to the recording material sheet P side that is in close contact with the film via the film 51, and the toner image Ta passes through the pressure contact part N. During this process, it is heated and becomes a softened and melted image Tb.

The rotationally driven fixing film 51 changes its traveling direction at a steep angle at an edge portion S of the heat insulating material 60 having a large curvature. Accordingly, the recording material sheet P, which is conveyed through the pressure contact portion N while overlapping with the fixing film 51, is separated from the fixing film 51 by the curvature at the edge portion S and is discharged.

By the time the toner reaches the paper discharge section, the toner has been sufficiently cooled and solidified and is completely fixed on the recording material sheet P (Tc).

(Problems to be Solved by the Invention) The following problems are listed as problems with such a film heating type device.

(1) If the alignment, such as the parallelism between the driving roller 52 and the driven roller 53 or between those rollers and the heating element 54, is out of order, the film should be A biasing force acts toward one end or the other end in the width direction.

Depending on the offset position of the film 51, problems may occur, such as the balance of the film conveyance force becoming unbalanced, the pressure force applied during fixing becoming unbalanced, and the temperature distribution of the heating element 19 becoming unbalanced.

Therefore, a sensor means for electrically detecting the shift of the film, a means for moving the film back in the direction opposite to the direction of shift according to the detection information, a means for changing the angle of a film pinch roller, etc. using a solenoid, etc. If a film shift movement control mechanism consisting of a mechanism or the like is added to restrict film shift, this will cause the device configuration to become more complicated, larger, and more expensive.

An object of the present invention is to provide a film heating type heating device using an endless heat-resistant film that solves the above-mentioned problems.

(Means for Solving the Problems) The present invention is a heating device characterized by the following configuration.

(1) A fixed heating body, an endless heat-resistant film whose inner surface is pressed against the heating body and is driven to move, and the film is sandwiched between the heating body to form a nip portion, and the nip portion is formed between the heating body and the endless heat-resistant film. a member introduced between the outer surface of the film and the outer surface of the film, which presses the recording material supporting the visible image against the heating body through the film; A heating device characterized in that it has a relational structure in which a biasing force always acts on one side, and a member that receives the end of the film on the film biasing side and restricts the shifting movement of the film.

(2) The film iT of the endless heat-resistant film is 20
The above (1) characterized in that μm≦T≦100 μm.
) The heating device described in item 2.

(3) The endless heat-resistant film is characterized in that the remaining circumferential portion of the endless heat-resistant film, excluding the portion sandwiched between the heating body and the pressure contact member, is tension-free when not driven. The heating device described in section 1).

(4) When the endless heat-resistant film is driven, the portion between the nip portion and the film inner guide portion in the vicinity of the nip portion, which is upstream of the nip portion in the film movement direction, and the nip portion The above-mentioned (
The heating device described in section 1).

(Function) (1) When the film is driven and the heating element generates heat, the nip formed between the heating element and the pressing part with the film sandwiched between the film and the old pressing part. When the recording material is introduced with the image-bearing surface facing the film, the recording material comes into close contact with the outer surface of the film and moves through the nip section together with the film, and in the process of moving and passing, it comes into contact with the inner surface of the film at the nip section. Thermal energy of the heating body is applied to the recording material through the film, and the recording material supporting the visible image is heat-treated by a film heating method.

(2) When the film is driven, the direction of the film in the width direction of the film is always in one direction, and the end of the film on that side is connected to the regulating member of the film end on that side and the flange member. By controlling the angle of the film using means such as a guide member that engages with the film rib, it becomes possible to stably and easily control the deviation of the film with a simple f-film configuration. As a result, when the apparatus is an image heat fixing apparatus, a good fixed image can always be produced stably.

(3) Taking into account thermal conductivity and rigidity, the film thickness T is generally set to 20μm≦T≦100μm, so that the edge of the film on the shifting side can be forcibly controlled by a regulating member such as a flange member. Even when the film is regulated, the edges of the film do not buckle or wrinkle, and the regulation is controlled in a stable manner.

(Embodiment) The drawing shows an embodiment of the present invention (image heat fixing device 100).
).

(1) Overall schematic structure of the device 100 FIG. 1 is a cross-sectional view of the device 100, FIG. 2 is a longitudinal sectional view, FIGS. 3 and 4 are right and left side views of the device, and FIG. is an exploded perspective view of main parts.

1 is a horizontally long device frame (bottom plate) with a two-way channel (groove) cross section made of sheet metal, 2 and 3 are this device frame 1
A left side wall plate and a right side wall plate are integrally provided to the frame 1 at both the left and right ends of the frame 1, and 4 is the upper cover of the device, which is fitted between the upper ends of the left and right side wall plates 2 and 3 to cover the left and right ends. It is fixed to the left and right side wall plates 2 and 3 with screws 5, respectively. It can be removed by loosening and removing the screw 5.

6 and 7 are vertical notched elongated holes formed symmetrically in the approximately central portions of the left and right side wall plates 2 and 3, and 8 and 9 are elongated holes 6 and 7, respectively.
These are a pair of left and right bearing members that are fitted into the lower end of the bearing member.

Reference numeral 10 denotes a film pressure roller (pressure contact roller, backup roller) as a rotating body that sandwiches the film with a heating body to be described later to form a nip portion and drives the film. It consists of a roller part 12 which is made of a rubber bullet having good release properties such as silicone rubber which is covered with a roller part 12, and the left and right ends of the central shaft 11 are rotatably supported by the left and right bearing members 8 and 9, respectively. .

Reference numeral 13 denotes a laterally elongated stay made of sheet metal, which serves as an inner kite member of the film 21 to be described later, and a supporting/reinforcing member for the heating body 19 and the heat insulating member 20 to be described later.

The stay 13 is provided with a horizontally long flat bottom part 14 and a series of raised sides from both sides of the bottom part 14.
It has a front wall plate 15 and a rear wall plate 16 having an outwardly arcuate cross section, and a pair of horizontally extending lug portions 17 and 18 of the left I-go projecting outward from both left and right ends of the bottom portion 14, respectively. are doing.

Reference numeral 19 denotes a horizontally long low heat capacity linear heating body having a structure (FIG. 6) to be described later, and it is supported by a horizontally long heat insulating member 20, and this heat insulating part 20 is placed on the heating body 19 side. It is integrally mounted parallel to the lower surface of the horizontally long bottom surface portion 14 of the stay 13 with the surface facing downward.

21 is an endless heat-resistant film;
- It is externally fitted onto the stay 13 including the heat insulating member 20. The inner circumferential length of the endless heat-resistant film 21 and the outer circumferential length of the step 13 including the heating element 19 and the heat insulating member 20 are larger than that of the film 21 by, for example, 3 mm. - Ste including the heat insulating member 20 =
13, it is loosely fitted around the circumference with some margin.

Reference numeral 23 designates a film end regulating flange member that is fitted onto and supported by the horizontally extending lug portion 18 at the right end of the stay 13.

Reference numeral 25 denotes a horizontally extending lug portion projecting outward from the outer surface of the flange member 23, and the outward horizontally extending lug portion 18 on the side of the stay 13 is located within the wall thickness of the horizontally extending lug portion 25 of this flange member 23. The flange member 23 is firmly supported 17 by fully fitting into the insertion hole provided in the flange member 23.

In the device of the wooden embodiment, there is no flange member on the left side of the film 21 for regulating the end of the film on that side, and a lug part as a spring receiver is provided on the horizontally extending lug part 17 on the left side of the stay 13. 24 is fitted externally.

To assemble the device, remove the upper cover 4 from between the left and right side wall plates 2 and 3, and attach the film pressure roller 10 with the left and right bearing members 8 and 9 fitted in advance to the left and right ends of the shaft 11.
Fit and engage the left and right bearing members 8 and 9 into the vertical notched elongated holes 6 and 7 of the left and right side wall plates 2 and 3 from the open upper end, and insert the pressure roller 10 between the left and right side wall plates 2 and 3. , lower it to the position where the left and right bearing members 8 and 9 are received by the lower ends of the elongated holes 6 and 7 (drop-in type).

Next, the intermediate assembly in which the stay 13, the heating body 19, the heat insulating member 20, the film 21, the right flange member 23, and the left arm portion 24 are assembled in advance in the relationship shown in the figure is attached to the heating body 19.
With the side facing downward, the left and right outwardly protruding ends and left and right outwardly extending horizontally projecting lug portions 24 and 25 of the heat insulating member 20 are opened at their upper ends into the vertical notched elongated holes 6 and 7 of the left and right side wall plates 2 and 3, respectively. The pressure roller 10 is inserted between the left and right side wall plates 2 and 3 by being fitted and engaged with each other, and the pressure roller 10 installed earlier is inserted into the receiver 1 with the heating element 19 facing downward or the film 21 sandwiched therebetween. (drop-down type).

Then, the left and right outwardly projecting lug portions 24 and 25 protrude through the elongated holes 6 and 7 to the outside of the left and right side wall plates 2 and 3.
The coil springs 26 and 27 are positioned vertically on the upper surface of the upper cover 4 by positioning them with support protrusions provided on the upper surface of the lug portion, and the cover 4 is placed on the outer surface of the upper cover 4. The side protruding lug parts 28 and 29 correspond to the upper ends of the coil springs 26 and 27 set above, respectively, and the coil springs 26 and 29 are connected to each other.
27 between the lug parts 24, 28, 25, and 29, and then fit it into the specified position between the upper ends of the left and right side wall plates 2 and 3, and then tighten it between the left and right side wall plates 2 and 3 using screws 5. Fix it.

As a result, the stay 13, heating element 19, heat insulating member 20, film 21,
The entire right flange member 23 and left lug portion 24 are pressed downward, and the heating body 19 and the pressure roller 10 are pressed against the film 2.
The longitudinal parts are held in substantially equal contact with each other with a total contact pressure of 4 to 7 kg, for example.

30 and 31 are the left side of the heat insulating member 20 that protrudes from the left and right side wall plates 2 and 3 through long holes 6 and 7! These are power supply connectors for supplying power to the heating body 19, which are fitted to both ends of the heater.

Reference numeral 32 denotes a heated material population guide attached to the cross-sectional wall of the device frame 1, and a recording material sheet P (first 7) between the heating body 19 and the pressure roller 10, which are pressed against each other with the film 21 in between (heat fixing section)
It is guided between the N film 21 and the roller 10.

Reference numeral 33 denotes a heated material exit guide (separation kite) installed on the rear wall of the apparatus frame 1, which guides the recording material sheet that has passed through the nip section to the lower discharge roller 34 and the upper pinch roller 38. Guide to the nip area.

The discharge roller 34 has both left and right ends of its shaft 35 rotatably supported between bearings 36 and 37 provided on the left and right side wall plates 2 and 3. The pinch roller 38 has a hook portion 40 formed by bending a part of the rear wall of the upper cover 4 inward at its shaft 39.
The discharge roller 34 is brought into contact with the upper surface of the discharge roller 34 by its own weight and the pressure spring 41. This roller 38 rotates as a result of the rotation of the discharge roller 34.

G1 is a roller shaft 11 that projects outward from the right side wall plate 3.
The first gear, G3, is fixed to the right side of the right side wall plate 3.
A third gear G2 fixed to the right end of the discharge roller shaft 35 projecting outward from the shaft is a second gear serving as a relay gear pivotally attached to the outer surface of the right side wall plate 3, and is connected to the first gear G2. G1
and the third gear G3.

The first gear G1 receives a driving force from a driving gear GO of a drive source mechanism (not shown), and the pressure roller 10 is rotated counterclockwise in FIG. 1, and in conjunction with this, the rotational force of the first gear G1 is It is transmitted to the third gear G3 via the second gear G2, and the discharge roller 34 is also rotationally driven in the counterclockwise direction in FIG.

(2) Operation When the endless heat-resistant film 21 is not driven, the remaining part of the endless heat-resistant film 21 except for the part sandwiched between the nip N between the heating body 19 and the pressure roller 10 is shown in the enlarged view of the main part in FIG. Most of the substantially entire circumferential length is tension-free (a state in which no tension is applied).

When the drive is transmitted from the drive gear GO of the drive source mechanism to the first gear G1 and the pressure roller 10 is rotated at a predetermined circumferential speed in the counterclockwise direction (FIG. 7), the film 2 is cut at the nip N. A feeding movement force is applied to the endless heat-resistant film 21 due to the frictional force with the rotating pressure roller 10, and the inner surface of the film slides on the surface of the heating body 19 at approximately the same speed as the circumferential rotational speed of the endless heat-resistant film 21 or the pressure roller 10. It is driven to rotate in direction A.

In this driving state of the film 21, a pulling force f acts on a portion of the film upstream of the nip portion N in the film rotation direction, so that the film 21 is pulled further than the nip portion as shown by the solid line in FIG. It comes into contact with the inner surface guide portion of the film near the nip portion on the upstream side in the rotational direction, that is, approximately the lower half surface portion of the outwardly curved front plate 15 serving as the inner surface guide of the film of the stay 13 on which the film 21 is externally fitted. It rotates while causing sliding motion.

As a result, the rotating film 21 rotates with tension acting on the film portion B from the starting point 0 of the contact sliding portion with the front plate 15 to the nip portion N on the downstream side in the film rotation direction. As a result, wrinkles are prevented from occurring on at least the film portion surface, that is, the film portion surface B near the recording material sheet entrance side of the nip portion N, and the film portion of the nip portion N by the action of the tension described above.

Then, in the state where the film is driven as described in 2 above and the heating element 19 is energized, the recording material sheet P carrying the unfixed toner image Ta as the material to be heated is guided by the recording material 32 to the nip portion N. rotating film 21 and pressure roller 1
When the recording material sheet P is introduced with the image bearing surface facing upward between the film 21 and the film 21, the recording material sheet P moves and passes through the nip portion N together with the film 21. Heating body 19 in contact with the inner surface of the film at N
Thermal energy is applied to the recording material sheet P via the film, and the toner image Ta becomes a softened and fused image Tb.

The recording material sheet P that has passed through the nip portion N leaves the surface of the film 21 with the toner temperature below the glass transition point, is guided between the discharge roller 34 and the punch roller 38 by the exit logite 33, and is sent out of the apparatus. It will be done. Recording material sheet P
The softened/melted toner image Tb is cooled and fixed as an assimilation image TCL/ during the time when the toner image Tb exits the nip portion N, flows from the surface of the film 21, and reaches the discharge roller 34.

As described above, the recording material sheet P introduced into the nip portion N is under tension and moves in the nip portion N together with the film 21 while always being in close contact with the unwrinkled film surface, thereby eliminating wrinkles. To prevent uneven heating and fixing caused by a certain film passing through the nip portion N, and to prevent creases on the film surface.

The film 21 has a total circumferential length of -2N both when being driven and when being driven.
Or, since tension is applied only to B-H, that is, when not driven (Fig. 6), the film 21 is at the nip portion N.
Almost the entire circumference of the remaining part, excluding Since most of the entire circumference is tension-free, and a film with a short circumference can be used for the entire circumference, the drive required for driving the film is 1.
Herc is small, film device configuration, parts,
The drive system configuration is simplified, smaller, and lower in cost.

Also, when the film 21 is not driven (FIG. 6) and when it is driven (FIG. 7),
In Figure), tension is only applied to the film 21 at -2N or B-H of the entire circumference as described above, so even if the film 21 shifts in the film width direction when the film is driven, the shift force will be applied to the film 21. is small.

In addition, in the case of the device of this embodiment, the left and right coil springs 26
・The pressing force f27 of the right spring 27 which is the drive side of 27 (
Fig. 2) is the pressing force f2 of the left spring 26 on the non-drive side.
When the film 21 is being driven, by setting it higher than 6 (f27>f26), when the film 21 is being driven, the film 21 always has a biasing force directed toward the right R in the film width direction along the length of the step 13. This is how it works.

By restricting only the edge of the film 21 on the side R with the right flange member 27 serving as a restriction member, it is possible to stably and easily control the deviation of the film. As a result, when the apparatus is an image heat fixing apparatus, a stable and good fixed image can always be obtained.

Similar effects can be obtained both in the case of a tension-type device configuration in which the film is driven by applying tension around its entire circumference, and in the case of a tension-free type device configuration like the device of this embodiment. However, the means configuration is particularly suitable for tension-free types.

That is, in a tension-free type device, even if the film 21 shifts R and comes into contact with its right edge or the concave inner surface 23a of the right flange member 23, the film shift force is small, so the film does not respond to the shift force. The film has sufficient rigidity and does not cause damage such as buckling or breakage of the film edges.

In addition, since a simple flange member 23 as in the device of this embodiment is sufficient as the film deviation regulating means, the device configuration can be simplified, downsized, and lowered in cost, resulting in an inexpensive and highly reliable device. Can be configured.

In addition to the flange member 23 in the case of the device of this embodiment, the film deviation regulating means may include, for example, a rib made of heat-resistant resin provided in the circumferential direction of the endless film at the end of the film 21, and regulating the rib. Good too.

Furthermore, as the film 21 to be used, the rigidity can be reduced by the reduction in the biasing force as described above, so a film with a thinner wall and a smaller heat capacity can be used to improve the quick start performance of the device. .

Further, as a means for always moving the film 21 toward one side in the width direction during driving, in addition to using different pressing forces of the left and right pressing springs 26 and 27 as in the device of this embodiment, Take measures such as changing the shape and the shape of the roller 10 between the driving end and the non-driving end to control the film conveyance force so that the film always shifts in one direction. I can do it.

(3) Regarding film 21.

In order to reduce the heat capacity of the film 21 and improve quick start performance, the film thickness T of the film 21 is set to a total thickness of 10
A single layer or composite layer film having heat resistance, mold releasability, strength, durability, etc. of 0 μm or less, preferably 40 μm or less, and 20 μm or more can be used.

For example, polyimide polyetherimide (PE I
)・Polyethersulfone (PES) Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (
PFA) ・Polyetheretherketone (PEE
), polyparabanic acid (PPA), or a composite layer film, such as a 20 μm thick polyimide film, at least on the image contact side, PTFE (tetrafluoroethylene resin), fluororesin such as PAF-FEP, silicone resin, etc. Conductive materials (carbon black, graphite,
A releasable coating layer containing conductive whiskers, etc.)
For example, it is applied to a thickness of μm.

(4) Regarding the heating body 19 and heat insulating member 20.

The heating element 19 is arranged along the same line as the heating element 54 of the apparatus shown in FIG.
Heating element) 19b, surface protective layer 19c, temperature measuring element 1.9
It consists of d etc.

The heater board 19a is a heat-resistant, insulative, low heat capacity, and highly thermally conductive member, and has, for example, a thickness of 1 mm, a width of 10 mm, and a thickness of 1 mm.
It is an alumina substrate with a length of 240 mm.

The heating element 19b is located on the lower surface of the heater board 19a (film 21
For example, Ag
An electrically resistive material such as /Pd (silver palladium), Ta2N, RuO2, etc. is coated in the form of a line or strip with a thickness of about 10 μm and a width of 1 to 3 mm by screen printing, etc., and heat-resistant glass is applied as a surface protective layer 19c on top of it. It is coated with a thickness of approximately 10 μm.

For example, the temperature measuring element 19d is provided by applying a coating using a screen EIIJ printing method or the like to the approximate center of the -F surface (the opposite side to the surface on which the heating element 19b is provided) of the heater board 19a.
It is a low heat capacity temperature measuring resistor such as T-film. Thermistors with low heat capacity can also be used.

In the case of the heating element 19 of this example, the heating element 19b having a linear or narrow strip shape is energized at a predetermined timing in response to an image formation start signal to generate heat over substantially the entire length of the heating element 19b.

The power supply is AClooV, and the supplied power is controlled by controlling the phase angle of the current supply by a power supply control circuit (not shown) including a triac according to the temperature detected by the temperature measuring element 19c.

By energizing the heating element 19b of the heating element 19, the surface of the heating element quickly reaches the required fixing temperature (for example, 140 to 200°C) because the heat capacity of the heater board 19a, heating element 1.9b, and surface protective layer 19c is small. The temperature rises to .

The heat-resistant film 21 in contact with the heating body 19 also has a small heat capacity, and the recording material sheet P in pressure contact with the film is generated by the thermal energy of the heating body 19 through the film 21.
The image is effectively transferred to the side and heat-fixed.

As mentioned above, the surface temperature of the film facing the heating weight 9 rises to a high enough temperature relative to the melting point of the toner (or the temperature at which it can be fixed to the recording material sheet P) in a short time, so it has excellent quick start properties. There is no need for so-called standby temperature control in which the temperature of the heating element 19 is raised in advance, and energy saving can be realized, and temperature rise inside the machine can also be prevented.

The heat insulating member 20 insulates the heating element 19 to make effective use of heat generated, and is made of materials having heat insulating properties and high heat resistance, such as pps (polyphenylene sulfide), PAT (polyamide imide), and PI (polyimide).・PEEK
(polyetheretherketone), liquid crystal polymer, and other highly heat-resistant resins.

(5) Regarding film width C and nip length.

As shown in the dimensional relationship diagram in FIG. 8, the width of the film 21 is C, and the length of the nip formed by the pressure contact between the heating body 19 and the rotating pressure roller 1o with the film 21 in between is D. In this case, it is preferable to set the relationship such that C<D.

That is, contrary to the above, when the film 21 is conveyed by the roller 10 with the relational configuration C20, the film conveying force (pressing force) received by the film portion within the nip length area and the film outside the nip length area are The inner surface of the former film portion is slidably transported in contact with the surface of the heating element 19, while the inner surface of the latter film portion is made of a different material from the surface of the heating element 19. Heat insulation member 20
Since the film 21 is slidably conveyed in contact with the surface thereof, there is a possibility that damage such as wrinkles or folds may occur at both ends of the film 21 in the width direction due to the large difference.

On the other hand, by setting the relational structure of C<D, the inner surface of the entire length region C in the width direction of the film 21 contacts the surface within the length range of the heating element 19 and slides on the surface of the heating element. Since the film is conveyed, the film conveyance force is made uniform in the entire length region C in the film width direction, and the above-mentioned problem of film end damage is avoided.

Furthermore, since the pressure roller 10 used as a rotating body in this embodiment is made of a rubber material with excellent elasticity such as silicone rubber,
When heated, the coefficient of friction on the surface changes. Therefore, when E is the length range dimension of the heating element 19b of the heating element 19, the friction coefficient between the roller 10 and the film 21 at the part corresponding to the length range E of the heating element 19b and the length of the heating element 19b The coefficient of friction between the roller 10 and the film 21 in the portion outside the range E/corresponding to IIIJ is different.

However, by setting the dimensional relationship configuration of E<C<D, the difference between the length range E of the heating element 19b and the film width C can be made small, so that the difference between the length range E of the heating element 19b and the outside The influence of the difference in friction coefficient between the roller 10 and the film 21 on the transport of the film can be reduced.

This makes it possible to stably drive the film 21 with the roller 10, making it possible to prevent damage to the edges of the film.

Flange members 22 and 23 as film end regulating means
The film end regulating surfaces 22a and 23a are the pressure roller 10.
The length is within the range of , and even if the film shifts, damage to the edges of the film can be prevented.

(6) Regarding the pressure roller 10.

The pressure roller 10, which forms a nip N with the film 21 sandwiched between it and the heating body 19 and serves as a rotating body for driving the film, is made of a rubber elastic body with good mold release properties, such as silicone rubber, for example. 9 (A) or (B) rather than a straight shape in the longitudinal direction.
It is preferable to use an inverted crown shape as shown in the exaggerated model diagram (), or a substantially inverted crown shape in which the @ part of the inverted crown is cut 12a.

When the effective length H of the roller 1o is, for example, 230 mm, the degree d of the inverted crown may be set to d-100 to 200 μm.

That is, in the case of the Stray I shape, due to variations in component precision, etc., the pressure distribution in the film width direction applied to the film 21 by the roller at the nip N with the heating element 19 is more concentrated in the center than in the widthwise ends of the film. Sometimes it was higher. In other words, the conveying force of the film by the roller is greater at the center than at the ends in the width direction of the film, and as the film 21 is conveyed, a force acts on the film 21 that causes the portion of the film with a smaller conveying force to approach the portion of the film with a larger conveying force. This may cause wrinkles to appear in the film as it approaches the edges of the film or the center of the film.
Furthermore, when the recording material sheet P is introduced into the nip portion N, wrinkles may occur in the recording material sheet P during the conveyance process through the nip portion.

On the other hand, by forming the pressure roller 10 into an inverted crown shape, the pressure distribution in the film width direction applied by the roller to the film 21 at the nip N with the heating element 19 is opposite to the above case. The edges in the width direction are larger than the center, and as a result, a force acts on the film 21 from the center toward both ends, that is, the film 21 is conveyed while receiving the effect of smoothing out wrinkles.
It is possible to prevent wrinkles on the film and also to prevent wrinkles on the introduced recording material sheet P.

The pressure roller 10 as a rotary body presses the film 21 against the heating body 19 by sandwiching the film 21 between it and the heating body 19 as in the apparatus of this embodiment, and drives the film 21 to move at a predetermined speed. When a recording material sheet P as a heated material is introduced between the film 21 and the film 21, a driving member drives the recording material sheet P in close contact with the surface of the film 21 and presses it against the heating body 19 to move it together with the film 21 at a predetermined speed. By doing so, it is possible to reduce the shifting force applied to the film, and it is also possible to improve the positional accuracy of the pressure roller 10 and the gear for driving the roller.

That is, the film 21 or the film 2
1 and the recording material sheets 1 to P are brought into pressure contact with each other;
When the driving function of moving the film 21 is performed by separate pressurizing function rotary bodies (the necessary pressurizing force is obtained by pressurizing this rotary body) and film drive function rotary bodies, respectively, If the alignment between the heating element 19 and the film drive rotor is out of alignment, a large biasing force will act on the thin film 21 in the width direction, and the edges of the film 21 may be damaged, such as folds or wrinkles. There is.

In addition, a heating body 1 is attached to the pressurizing rotary body that also serves as a film drive member.
When applying the pressure necessary for pressure contact with 9 by pressing with a spring or the like, the position of the rotary body and the positional accuracy of the gear for driving the rotary body can be ensured.

On the other hand, as described above, a pressure force necessary for fixing is applied to the heating body 19, and the recording material sheet P is pressed against the film 21 by the pressure roller 10, which is a rotating body.
By driving the recording material sheet P and the film 21 at the same time, the above-mentioned effects can be obtained, and the structure of the apparatus can be simplified, making it possible to obtain an inexpensive and highly reliable apparatus.

Note that instead of the roller 10, the rotating body may be an endless belt IOA that is rotationally driven as shown in FIG.

The configuration in which the rotating body 10/IOA has the function of pressing the film 21 against the heating body 19 and the function of driving the film 21 is similar to the apparatus of the above-mentioned example in FIG. The same effect can be achieved by applying it to film tension type devices such as those used for film shifting, and regardless of whether the film deviation regulating means is a sensor/solenoid method, a rib regulating method, a film edge (both sides or one side) regulating method, etc. Although this method is effective, it is particularly suitable for use in tension-free type devices.

(7) Regarding recording material sheet ejection speed.

The conveyance speed of the recording material sheet P as a heated material introduced into the nip portion N by the pressure roller 10 (rotating body), that is, the circumferential speed of the roller 10 is VtO, and the recording material sheet discharge conveyance speed of the discharge roller 34 is That is, when the circumferential speed of the discharge roller 34 is VB2, it is preferable to set the speed relationship to be VIO>VB2. The speed difference may be set to several percent, for example, about 3%.

When the maximum width of the recording material sheet P that can be introduced into the apparatus and used is F (see FIG. 8), in relation to the width C of the film 21, under the condition of F<C, VIO≦V3.
4, the recording material sheet 1-P is being conveyed across the nip portions N and U [the ejecting roller 34], and the sheet portion passing through the nip portion N is the ejecting roller 34. 34 lengthens the bow 1-)1.

At this time, the film 21 whose surface is coated with a coach ink such as PTFE having good releasability is being conveyed at the same speed as the pressure roller 10.

In addition to the conveyance force by the pressure roller 10, a tensile conveyance force by the discharge roller 34 is also applied to the recording material sheet P.
It is transported at a speed faster than the circumferential speed of the pressure roller 10. In other words, the recording material sheet 1-P and the film 21 slip in the nip portion N, and as a result, the recording material sheet P slips while the recording material sheet P passes through the nip portion N.
There is a possibility that the above unfixed toner image Ta (FIG. 7) or the toner image Tb that has been softened and melted will be disturbed.

Therefore, as described above, by setting the circumferential velocity VtO of the pressure roller 10 and the circumferential velocity V34 of the discharge roller 34 in the relationship VIO>VB2, the recording material sheet P and the film 2
1 is given only the conveying force of the pressure roller 10 which causes the pulling tension force of the discharge roller 34 to act on the sheet P.
The above-mentioned image holes can be prevented from occurring due to slippage between the sheet P and the film 21.

Although the discharge roller 34 is provided on the heating device 100 side in this embodiment, it may be provided on the Kasagi machine side of the image forming apparatus into which the heating device 100 is incorporated.

three (8) Regarding the friction coefficient relationship between each member.

a, roller (rotating body) 1 against the outer peripheral surface of the film 21
0 surface friction coefficient μm, b, friction coefficient of the heating body 19 surface against the inner peripheral surface of the film 21 μ2, C1 friction coefficient of the roller 10 surface against the heating body 19 surface μ3, d, record as heated material The friction coefficient of the outer peripheral surface of the film 21 against the surface of the recording material sheet 2 is μ4, e, the friction coefficient of the surface of the roller 10 against the surface of the recording material sheet P is μ5, f, the maximum length in the transport direction of the recording material sheet P introduced into the apparatus When the device is incorporated into a transfer type image forming device as an image heat fixing device, the recording material from the image transfer means section to the nip portion N of the device as the image heat fixing device. The conveyance path length of the sheet (transfer shrine) P is assumed to be f12.

Therefore, the relationship between μm and μ2 is μm〉μ2 The relationship structure is as follows.

That is, in this type of film heating type device, the relationship between μ4 and μ5 is set as μ4<μ5, and in the image forming device, the relationship between fLl and °C2 is ul>12.
It becomes.

At this time, if μm≦μ2, the film 21 and the recording material sheet P slip in the cross-sectional direction of the heat fixing means (the conveying speed of the film 2 is delayed relative to the circumferential speed of the roller 10).
The toner image on the recording material sheet is disturbed during heat fixing.

In addition, if the recording material sheet P and the film 21 slip together (the transport speed of the film 21 and the recording material sheet P is delayed relative to the peripheral speed of the roller 10), in the case of a transfer type image forming apparatus, the image transfer When the toner image is transferred onto the recording material sheet (transfer material) in the means section, the toner image on the recording material is also disturbed.

By setting μm>μ2 as described above, the film 2j and the recording material sheets 1 to P with respect to the roller 10 in the cross-sectional direction
can prevent slipping.

Furthermore, regarding the width C of the film 21, the length H of the roller 10 as a rotating body, and the length H of the heating body 19, under the conditions of C<H and C<D, the relationship configuration is μm>μ3. Make it.

That is, in the relationship of μl≦μ3, in the width direction of the heat fixing means,
The film 21 and the roller 10 slip, and as a result, the film 21 and the recording material sheet P slip, and the toner image on the recording material sheet is disturbed during heat fixing.

By configuring the relationship μm>μ3 as described above, it is possible to prevent the film 21 from slipping against the roller 10 in the width direction, particularly on the outside of the recording material sheet P.

By setting μm>μ2 and μm>μ3 in this way,
The conveying speed of the film 21 and the recording material sheet P can always be made the same as the peripheral speed of the roller 10, and it is possible to prevent image disturbance during fixing or transfer.
2. By performing μm>μ3 at the same time, roller 1
It becomes possible to always make the peripheral speed of 0 (=process speed) and the conveying speed of the film 21 and the recording material sheet P the same, and a stable fixed image can be obtained in the transfer type image forming apparatus.

(9) Example of Image Forming Apparatus FIG. 11 shows a schematic configuration of an example of an image forming apparatus incorporating the image heating fixing apparatus 100 shown in FIGS. 1 to 10.

The image forming apparatus of this example is a laser beam printer using a transfer type electrophotographic process.

60 is a process cartridge, which includes a rotating drum type electrophotographic photoreceptor (hereinafter referred to as drum) 61 and a charger 62
- It includes four process devices: a developing device 63 and a cleaning device 64. This process cartridge can be attached to and removed from a predetermined position within the apparatus by opening the opening/closing part 65 of the apparatus and opening the inside of the apparatus.

The tram 61 is rotationally driven in the clockwise direction as indicated by the image forming start signal, and the surface of the rotating drum 61 is connected to the charger 62.
A laser beam 67 is uniformly charged to a predetermined polarity and potential by a drum, and is outputted from a laser scanner 66 to the charged surface of the drum, and is modulated in accordance with a time-series electric digital pixel signal of target image information. As a result of main scanning exposure, electrostatic latent images corresponding to target image information are sequentially formed on the surface of the drum 61. The latent image is then developed into a toner image by a developing device 63.

On the other hand, the recording material sheets P in the paper feed cassette 68 are separated and fed one by one by the cooperation of the paper feed roller 69 and the separation bat 70, and are synchronized with the rotation of the drum 61 by a pair of registration rollers 71 to be transferred to the tram 61. and a transfer roller 72 that is in opposing pressure contact with the transfer roller 72 and is fed to a pressure nip 73 that is a fixing section,
The toner image on the drum 1 side is sequentially transferred to the feeding recording sheet P side.

The recording material sheets 1 to P that have passed through the transfer section 73 are separated from the surface of the drum 61 and introduced into the fixing device 100 by the kite 74, and the unfixed toner image is heated and fixed by the operation and action of the device 100 described above. The image is then output from the output lower 5 as an image formed product (print).

The surface of the drum 61 from which the recording material sheet P has been separated through the transfer section 73 is subjected to removal of adhered contaminants such as untransferred toner by a cleaning device 64, and is used repeatedly for image formation.

The heating device of the present invention can be effectively utilized not only as an image heating fixing device of the image forming apparatus described above, but also as an image surface heating polishing device and a temporary fixing device.

(Effects of the Invention) As described above, the film heating type heating device of the present invention is such that the film is always shifted in one direction and only the end of the film is regulated by the regulating member. This makes it possible to stably and easily control the film deviation, making it possible to consistently obtain clean and good heat-fixed images.Also, since it is a simple film deviation control means, the device configuration can be simplified.・Small size/low cost 1~
The device is stable and reliable.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the device. Figure 2 is a longitudinal sectional view. Figure 3 is a right side view. Figure 4 is a left side view. FIG. 5 is an exploded perspective view of the main parts. FIG. 6 is an enlarged cross-sectional view of the main part showing the state of the film when not driven. FIG. 7 is the same diagram as above when driving. FIG. 8 is a dimensional relationship diagram of the constituent members. Figures 9 (A) and (B) show the roller 0 as a rotating body, respectively.
An exaggerated shape diagram showing an example of the shape. FIG. 10 is a diagram showing an example in which a rotating belt is used as the rotating body. FIG. 11 is a schematic configuration diagram of an example of an image forming apparatus. FIG. 12 is a schematic diagram of a known example of a film heating type image heating fixing device. 19 is a heating body, 21 is an endless film, 13 is a stay, and 10 is a roller as a rotating body.

Claims (4)

[Claims] (1) A fixed heating body, an endless heat-resistant film whose inner surface is pressed against the heating body and is driven to move, and the film is sandwiched between the heating body to form a nip portion, and the nip portion is formed by sandwiching the film between the heating body and the heating body. a member introduced between the outer surface of the film and the outer surface of the film, which presses the recording material supporting the visible image against the heating body through the film; A heating device characterized in that it has a relational structure in which a shifting force always acts on one side, and a member that receives the edge of the film on the film shifting side and restricts shifting movement of the film. (2) The thickness T of the endless heat-resistant film is 20
Claim 1 characterized in that μm≦T≦100 μm.
Heating device as described. (3) The endless heat-resistant film is characterized in that the remaining circumferential portion of the endless heat-resistant film excluding the portion sandwiched between the nip portion between the heating body and the pressing member is tension-free when not driven. 1. The heating device according to 1. (4) When the endless heat-resistant film is driven, the portion between the nip portion and the film inner guide portion in the vicinity of the nip portion, which is upstream of the nip portion in the film movement direction, and the nip portion 2. The heating device according to claim 1, wherein the heating device has a relational configuration in which tension is applied only at only one portion of the heating device.