JPH04204982A - Heater - Google Patents

Abstract

PURPOSE:To drastically reduce the cost of the heater of a film heating system by forming an endless heat resistant film into a multilayered structure and forming at least one layer by extrusion molding of a thermoplastic resin having high heat resistance. CONSTITUTION:The endless heat resistant film 21 is the multilayered structure film obtd. by an extrusion molding means. All the layers of this heat resistant film 21 consist of the thermoplastic resin having the high heat resistance successively from the inner layers and this film is obtd. by laminating and forming 3 layers; a base layer 21a, adhesive layer 21b and surface layer 21c. The efficient mass production of the endless heat resistant film obtd. in such a manner is possible and the production cost of the film is drastically reduced. The cost of the heater of the film heating type is eventually drastically reduced.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention involves bringing a recording material into close contact with a heating body through a heat-resistant film, and moving the heating body and the heat-resistant film relative to each other to absorb the heat of the heating body. The present invention relates to a heating device that applies heat to a recording material through a heat-resistant film (film heating method).

This device is an image heating fixing device in an image forming apparatus such as an electrophotographic copying machine, a printer, or a fax machine, that is, it is made of heat-melting resin, etc., by an appropriate image forming process means such as electrophotography, electrostatic recording, magnetic recording, etc. Unfixed toner that corresponds to the desired image information and is formed using toner on the surface of a recording material (transfer material sheet, electrofax sheet, electrostatic recording sheet, printing paper, etc.) using an indirect (transfer) method or a direct method. An image heat fixing device that heats and fixes an image as a permanently fixed image on the surface of a recording material carrying the image; a device that heats the recording material carrying the image to modify its surface properties (such as gloss); It can be used for devices that perform temporary attachment treatment.

(Background Art) Conventionally, for example, a heating device for a recording material 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 that heats the recording material while nipping and conveying it is often used.

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 proposed a film heating type heating device as described above in, for example, Japanese Unexamined Patent Publication No. 63-313182. This consists of a fixedly supported heating body, a heat-resistant film (or sheet) that is conveyed (moving and driven) while being in pressure contact with the heating body, and a pressure member that brings the recording material into close contact with the heating body through the film. This device has a system and structure in which an unfixed image formed and carried on the surface of the recording material is heated and fixed on the surface of the recording material by applying heat from a heating body to the recording material through a film.

More specifically, it includes a thin heat-resistant film, a means for moving the film, a heating element fixedly supported on one side of the film with the film inside, and the heating element on the other side. A pressure member is disposed opposite to the heating member and brings the image bearing surface of the recording material into close contact with the heating body through the film, and the film is in contact with the film at least when image fixing is performed. It is formed by pressing the heating body and the pressure member with the traveling film in between by moving it in the forward direction of the recording material to be fixed, which is conveyed and introduced between the pressure member and the recording material, at a substantially concave speed. By passing through a nip section serving as a fixing section, the developed image-bearing surface of the recording material is heated by the heating body through the film, and thermal energy is applied to the developed image (unfixed toner image) to soften and melt it. This is a heating means/device that basically separates the film and recording material after passing through the fixing section at a separation point.It uses a heating element with a quick temperature rise and a thin film to shorten waiting time (quick start). ), and has other advantages such as being able to solve various drawbacks of conventional devices.

FIG. 11 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 fixing film or simply film), which includes a driving roller 52 on the left side, a driven roller 53 on the right side, and a lower part between these driving rollers 52 and driven rollers 53. The three members 52 and 52 of the low heat capacity linear heating element 19 arranged in parallel to each other are
The suspension is installed between 53 and 19.

Fixing film 5! is a recording material as a heated material carrying on its upper surface an unfixed toner image Ta that is conveyed clockwise at a predetermined circumferential speed as the drive roller 52 is rotated in the clockwise direction; The conveying speed of the sheet P (the sheet P is rotated at approximately the same peripheral speed as the process speed).

Reference numeral 55 denotes a pressure roller as a pressure member, which holds the downward film portion of the endless belt-shaped fixing film 51 between it and the heating body 19, and attaches an unillustrated attachment to the lower surface of the heating body. The recording material sheet P is rotated forward and counterclockwise in the conveying direction of the recording material sheet P.

The heating body 19 is a low heat capacity linear heating body whose length is in the direction intersecting the plane movement direction of the film 51 (width direction of the film), and includes a heater substrate (base material) 19a and a heating element (current-carrying heating resistor) 19b. - It is made of a surface protection layer 19c, etc., and is fixedly supported by being attached to a support body 80 via a heat insulating member 20.

A recording material sheet P carrying an unfixed toner image Ta on its -E side, conveyed from an image forming section (not shown), is guided by a guide 81 to a pressure contact portion N (
The unfixed toner image surface enters between the fixing film 51 and the pressure roller 55 of the pressure nip portion), and the unfixed toner image surface is attached to the recording material sheet P.
The fixing film 51 is rotated in the same direction at the same speed as the conveying speed of go.

The heating body 19 is electrically heated at a predetermined timing, and the thermal energy on the heating body 19 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 portion N. During this process, it is heated and becomes a softened and melted image Tb.

The rotating direction of the fixing film 51 is changed at an acute angle θ at an edge portion S of the heat insulating member 20 having a large curvature. Therefore, the recording material sheet P, which is conveyed through the pressure contact part N while overlapping with the fixing film 51, separates from the fixing film 51 by the curvature at the edge part 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 endless film 51 as a fixing film is required to have the following properties.

a. It must have heat resistance at least equal to or higher than the heat treatment temperature of the recording material.

b. Must have mechanical strength (durability) that can withstand repeated use.

C1 Good releasability from recording material or visible image forming material (toner).

d) In order to reduce the heat capacity and improve quick start performance, the thickness may be thin, and even if the thickness is 100 μm or less, preferably 20 to 40 μm, the above-mentioned durability can be obtained.

Even if a single material does not satisfy all of the requirements a to b above, it is possible to satisfy the above requirements by creating a multilayer (composite layer) structure of two or more material layers and combining the characteristics of each material layer.

The endless film 51 as the fixing film in the apparatus shown in FIG. 11 uses a film having this laminated structure.

FIG. 12 shows a model diagram of its layer structure.

51a is a base layer made of polyimide (PI) resin. This PI resin layer has heat resistance (over 300°C) and is durable enough to withstand repeated use even if it is thin, so Endless Film 5 is used as a fixing film.
The characteristics of the a-term and b-term required for the first embodiment are shared.

51b is a surface layer of about 10 μm that is integrally laminated on the outer peripheral surface of the endless space layer 51a, and is made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) mixed with carbon as a conductivity imparting substance. This is a layer. This PFA resin layer has good releasability from the recording material or the image-forming material, and shares the characteristic of item 0 above. By blending a conductivity-imparting substance such as carbon into the PFA resin layer serving as the surface layer, the surface layer 51b can be made conductive, and the electrical charges on the endless film 51 as the fixing film can be eliminated. Negative effects such as image disturbance can be prevented.

In the case of this multilayer structure as well, the total thickness is set to 100 μm or less, preferably 20 to 40 μm to reduce the heat capacity.
Improve the quick start characteristics of the section.

The endless film 51 having such a multilayer structure is manufactured as follows. That is, a varnish-like assembly of PI resin constituting the base layer 51a is applied to the outer peripheral surface of a cylindrical or cylindrical mold having an outer diameter corresponding to the inner diameter of the target endless film 51 by a dipping method or the like, and then dried. An imidization reaction is performed to form a PI resin layer. For the formation of this PI resin layer, a layer with a thickness of about 10 μm can only be formed by one application and drying of the PI resin face-like composition.
The process of applying and drying the resin face composition is repeated several times, and therefore the manufacturing process takes several days.

When the PI resin layer as the base layer 51a with the desired thickness of several tens of micrometers is finally formed, it is cut out, and a combination of PFA resin + C is formed on the outer peripheral surface of the obtained endless PI film to form the surface layer 51b. Apply the composition by spraying, etc., put it in a furnace, and bake it (about 400°C) to a thickness of 1.
It is manufactured by integrally forming a surface layer 51b with a thickness of about 0 μm on the outer surface of the PI resin layer 51a and cutting it into a required length dimension.

Therefore, the endless heat-resistant film 51 as a fixing film has a long manufacturing cycle and a very high manufacturing cost, which is a problem in reducing the cost of a heating device using a film heating method. .

It is an object of the present invention to solve this problem and to make it possible to provide this type of heating device at low cost.

(Means for Solving the Problems) The present invention provides a fixed heating body, an endless heat-resistant film whose inner surface is pressed against the heating body and is driven to move, and a film between the heating body and the heating body. a member that presses the recording material to be heat-treated introduced between the film and the outer surface of the film at the nip portion into pressure contact with the heating body through the film, the endless heat-resistant film having a multilayer structure; The present invention is a heating device characterized in that at least one layer is an endless film formed by extrusion molding of a highly heat-resistant thermoplastic resin.

In addition, the present invention provides the above-mentioned heating device), which has a three-layer structure consisting of a base layer, an adhesive layer, and a surface layer in order from the inner side 1 of the endless heat-resistant film of the multilayer structure, and these three layers are simultaneously extruded. This heating device is characterized in that it is an endless film that is laminated by molding.

(Function) That is, by forming an endless heat-resistant film with a multilayer structure by extruding at least one layer, for example, a base layer, of a highly heat-resistant thermoplastic resin, the desired endless heat-resistant film can be formed as described above. Compared to other methods, it can be mass-produced much more efficiently, and therefore it is possible to significantly reduce film manufacturing costs, which in turn can greatly reduce the cost of film-heating heating equipment (in practice).
Example) The drawing shows an apparatus according to an embodiment of the present invention (image heat fixing apparatus 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) made of sheet metal with an upward channel (:a) cross section; 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 screws 5. '6 and 7 are long vertical notches formed symmetrically in the substantially central portions of the left and right side wall plates 2 and 3, and 8 and 9 are fitted into the lower ends of the respective elongated holes 6 and 7. These are a pair of left and right bearing members.

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 made of a rubber elastic body (with good mold releasability of silicone rubber etc. coated on the outside), and the left and right ends of the central shaft 11 are rotatably supported by bearings on the left and right bearing members 8 and 9, respectively. .

Reference numeral 13 denotes a horizontally long stay made of sheet metal, which serves as an inner surface guide member for the film 21 described later, and a supporting/reinforcing member for the heating body 19 and heat insulating member 20 described later.

This stay 13 includes a horizontally long flat bottom part 14, and a front wall plate 15 and a rear wall plate 16 each having an outwardly curved cross section and extending in series from both longitudinal sides of the bottom part 14.
It has a pair of left and right horizontally extending lug parts 17 and 18 that project outward from both left and right ends of the bottom part 14, respectively.

Reference numeral 19 denotes a horizontally long low heat capacity linear heating body having a structure (FIG. 9) to be described later, and is mounted and supported by a horizontally long heat insulating member 20, and the heat insulating member 20 is placed with the heating body 19 side facing downward. The stay 13 is integrally attached and supported in parallel to the lower surface of the oblong bottom surface portion 14.

21 is an endless heat-resistant film;
- It is externally fitted onto the stay 13 including the heat insulating member 20.

The endless heat-resistant film 21 is a multilayer film formed by extrusion molding, as will be described in detail in section (3) below.

The inner circumferential length of this endless heat-resistant film 21 and the outer circumferential length of the stay 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. The stay 13 including the heat insulating member 20 is loosely fitted around the stay 13 with a margin of circumference.

22 and 23 connect the film 21 to the heating body 19 and heat insulating member 20
These are a pair of left and right film end regulating flange members that are fitted onto the stay 13 containing the stay 13 and then fitted onto and supported by the horizontally projecting lug portions 17 and 18 at the left and right ends of the stay 13.

The distance between the inner surfaces 22a and 23a of the flanges of the left and right pair of flange members 22 and 23 is set to be slightly larger than the width of the film 210.

24 and 25 are the pair of left and right flange members 22 and 23.
This is a horizontally extending lug portion that protrudes outward from the outer surface of the stay 13 side.
The left and right flange members 22 and 18 are fully fitted into insertion holes provided within the wall thickness of the horizontally extending lug portions 24 and 25 of the flange members 22 and 23, respectively.
I firmly support 23.

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. , the left and right bearing members 8 and 9 are lowered to the position where they are stopped at 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, and the left and right flange members 22 and 23 are assembled in advance in the relationship shown in the figure, is placed with the heating body 19 facing downward and the heat insulating member The left and right outward protruding ends of 20 and the horizontally extending lug portions 2 of the left and right flange members 22 and 23
4 and 25 are fitted and engaged into the vertical notched elongated holes 6 and 7 of the left and right side wall plates 2 and 3 from the upper end openings, respectively, to form the left and right side wall plates 2 and 3.
Insert the film 21 between them and lower it until the downward heating body 19 hits the upper surface of the previously assembled pressure roller 10 with the film 21 in between and the receiver is stopped (drop-in type).

Coil springs 26 and 27 are provided on the upper surfaces of the lugs on the lugs 24 and 25 of the left and right flange members 22 and 23, respectively, which protrude through the elongated holes 6 and 7 on the outside of the left and right side wall plates 2 and 3. The upper cover 4 is positioned vertically with support protrusions, and the outer projecting lug parts 28 and 29 provided at the left and right ends of the upper cover 4 are attached to the upper ends of the coil springs 26 and 27 set above. While compressing the coil springs 26 and 27 between the lug parts 24, 28, 25, and 29, respectively, fit them into the specified positions between the upper ends of the left and right side wall plates 2 and 3, and tighten the left and right screws 5. Fix it between the side wall plates 2 and 3.

As a result, the stay 13, heating element 19, heat insulating member 20, film 21,
The entire left and right flange members 22 and 23 were pressed downward, and the heating body 19 and the pressure roller 10 were brought into contact with the film 21 almost equally on each longitudinal part with a total contact pressure of 4 to 7 kg, for example. held in state.

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

Reference numeral 32 denotes a heated material inlet guide installed on the front wall of the apparatus frame 1, and a recording material sheet P( (FIG. 7) is guided toward the nip portion (heat fixing portion) N between the film 21 and the pressure roller 10, where the heating body 19 and the pressure roller 10 are in pressure contact with the film 21 in between.

Reference numeral 33 denotes a recording material separation kite member attached to the rear wall of the apparatus frame 1, which passes through the nip N and separates the recording material sheet into the nip between the lower discharge roller 34 and the upper groove roller 38. Guide to the department.

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 receiver is inserted into the container and 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 as a relay gear pivotally attached to the outer surface of the right side wall plate 3, and is connected to the first gear described above. 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 rotationally driven in the counterclockwise direction in FIG. This 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 entire circumference is tension-free.

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 rotationally driven in the counterclockwise direction in FIG. A feeding movement force is applied due to the frictional force with the pressure roller 10, and the endless heat-resistant film 21 moves in the clockwise direction A while the inner surface of the film slides on the surface of the heating body 19 at approximately the same speed as the peripheral rotational speed of the pressure roller 10. It is driven to rotate and move.

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 moved further than the nip portion N as shown by the solid line in FIG. Contact with the inner surface guide portion of the film near the nip portion on the upstream side in the film rotation direction, that is, approximately the lower half portion of the outwardly curved front plate 15 serving as the inner surface guide of the stay 13 on which the film 21 is 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 O of the contact sliding portion with the front plate 15 to the nip 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, while the film is driven 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 entry logite 32 and rotates around the nip portion N. Dynamic film 21 and pressure roller 10
When the recording material sheet P is introduced with the image bearing surface facing upward,
is in close contact with the surface of the film 21 and moves through the nip N together with the film 21, and in the process of moving and passing, the thermal energy of the heating element 19 that is in contact with the inner surface of the film at the nip N is transferred through the film. The toner image Ta applied to the recording material sheet P becomes a softened and fused image Tb.

The recording material sheet P that has passed through the nip portion N is separated from the film 21 surface in a state where the toner temperature is higher than the glass transition point, and is guided by an exit guide 33 between a discharge roller 34 and a pinch roller 38 and sent out of the apparatus. . Recording material sheet P
The softened/melted toner image Tb is cooled and fixed as a solidified image TCL/ while it exits the nip portion N, leaves the surface of the film 21, and reaches the discharge roller 34.

As mentioned above, the recording material sheet P introduced into the nip part N is under tension and always adheres to the unwrinkled film part surface and moves through the nip part N together with the film 21, so that the wrinkled film is not produced. Occurrence of heating unevenness and fixing unevenness due to the situation where the liquid passes through the nip part N,
No creases on the film surface.

The film 21 has a part N of its total circumference both when being driven and when being driven.
Or, since tension is applied only to B-N, 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 almost the entire circumference is tension-free, and a film with a short circumference can be used throughout, the drive torque required to drive the film is small, and the film device configuration, parts, and drive system are The 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),
2), tension is applied to the film 21 only on part N or B-N of the entire circumference as described above, so when the film is driven, the film 21 is applied to one side Q in the film width direction (Fig. 2) or Even if a shift toward the other side R occurs, the shift force is small.

Therefore, the film 21 shifts Q or R and its left edge becomes the flange inner surface 22a as the film end regulating surface of the left flange member 22, or its right edge becomes the right flange member 23.
Even if the film comes into contact with the inner surface 23a of the flange seat, the film's biasing force is small, so the rigidity of the film sufficiently overcomes the biasing force, and the end of the film does not buckle or break. In addition, since the film deviation regulating means is sufficient with simple flange members 22 and 23 as in the device of this embodiment, the device configuration can be simplified, downsized, and lowered in cost in this respect as well, resulting in an inexpensive and highly reliable device. can be configured.

In addition to the flange members 22 and 23 in the case of the device of this embodiment, for example, a rib made of heat-resistant resin is provided at the end of the film 21 in the circumferential direction of the endless film as the film deviation regulating means, and this rib is regulated. 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 that the quick start performance of the device can be improved by using a film that is thinner and has a smaller heat capacity.

(3) Film 21 Endless heat-resistant film 21 as a fixing film
is a multilayer structure film obtained by extrusion means according to the present invention.

The endless heat-resistant film 21 of this embodiment has, as shown in the layer structure model diagram in FIG. It was obtained by laminating and forming three layers, 21b and 21c, using a known multilayer co-extrusion method. In FIG. 8, reference numeral 200 denotes a simultaneous extrusion die for extruding the three layers, the base layer 21a, the adhesive layer 21b, and the surface layer 21c, substantially concentrically into a tube shape.

The base layer 21a (2) is made of thermoplastic PI resin and is extruded into a tube shape with a wall thickness of, for example, about 40 μm.

The adhesive layer 21b (2) is made of thermoplastic PI which is a base layer resin.
It is a resin containing, for example, 30 to 40% by weight of carbon filler, and is extruded into a tube shape having a wall thickness of, for example, about 10 μm or less.

The surface layer 21c of (2) is made of PEA resin mixed with ~% by weight of carbon filler to impart conductivity.
It is extruded into a tube shape with a wall thickness of, for example, about 10 μm.

The above-mentioned base layer 21a and adhesive layer 21c, which are co-extruded concentrically into a tube shape, are bonded together into three layers to be continuously and efficiently mass-produced as a multilayered endless film 21, and then cut into appropriate lengths. It is used by being incorporated into a heating device as an endless fixing film 21.

The adhesive layer 21b is formed by adding the surface layer 21 to the constituent resin of the base layer 21a.
By using a material containing a conductivity imparting material such as a carbon filler mixed in c, the base layer 21a and the surface layer 21c are well bonded and integrated via the adhesive layer 21b.

The PI resin layer as the base layer 21c is responsible for the heat resistance and durability of the endless film 21 as the fixing film, and the PFA resin layer as the surface layer 21c is responsible for the releasability from the recording material.

In addition to PI resin, the base layer 21b may also be made of polyetherimide (PEI), polyethersulfone (PES), etc.
) Heat-resistant thermoplastic resins such as polyetheretherketone (for PEE) and polyparabanic acid (PPA) can also be used.

The surface layer 21c may be made of a thermoplastic fluororesin or silicone resin with excellent mold releasability such as FEP, or a material containing a conductive material (carbon black, graphite, conductive whiskers, etc.). You can also do it.

(4) Heating body 19 FIGS. 9(A) and 9(B) are partially cutaway plan views of the front surface side (which side of the heat-resistant film 21 is opposite) of the heating body 19 attached to the heat insulating member 20, respectively. and an enlarged cross-sectional view.

The substrate 19a is a member having heat resistance, electrical insulation, low heat capacity, and high thermal conductivity, and is, for example, an alumina substrate having a thickness of 1 mm, a width of 6 mm, and a length of 240 mm.

The heating element 19b is formed of, for example, Ag/Pd (silver palladium), Ta2
An electrically resistive material such as N or RuO2 is coated in a linear or narrow strip shape with a thickness of about 10 μm and a width of 1 to 3 mm by screen printing or the like.

Conductive patterns 19d are formed as first and second power feeding electrodes on the surface of the substrate on both ends of the long element of the heating element 19b.
- 19e are formed to be electrically connected to the ends of the heating elements.

The conductive pattern portions as the first and second power feeding electrode portions 19d and 19e are formed by coating, for example, by a screen printing method, and are made of a material with good conductivity, such as Au (gold).
These include Ag (silver) and Cu (copper).

Then, the heating element 19b, the first and second power feeding electrode parts 1
The surface of the substrate 19a on which the electrodes 9d and 19e are formed is coated with a glass material, P as a surface protective layer 19c, except for the surface portions on both ends of the substrate where the first and second power feeding electrode portions 19d are present.
Coating methods and baking methods with a layer of heat-resistant and film-sliding materials such as fluororesins such as FA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) and PTFE (polytetrafluoroethylene resin) are used. It is formed with a thickness of about 10 μm.

The heating body 19 having the above-mentioned structure is mounted and supported with the front side facing outward via the heat insulating member 20 on the bottom part 14 of the above-mentioned horizontally long stay 13 made of sheet metal as a support body.

In its attachment, in the supported state, the left and right ends of the heat insulating member 20 protrude outward from the left and right ends of the stay 13, and the power supply connectors 30 and 31 are fitted to the left and right outward protrusions.

The power supply connectors 30 and 31 are electrically connected to the first and second power supply electrode portions 19d and 19e, respectively, and are connected to a power supply circuit (not shown) via lead wires 30a and 31a, respectively.

As a result, the power supply circuit → lead wire 30a → first power supply connector 30 → first electrode part 19d of heating element 19 → heating element 19b → second electrode part 19e → second power supply connector 31 → lead wire 31a → Heating element 19b in the power supply circuit path
Electricity is applied to the heating element 19, causing the heating element 19 to generate heat.

Although not shown in the figure, a temperature measuring element such as a low heat capacity thermistor or a low heat capacity temperature measuring resistor such as a PT film, or a safety element such as a fuse is provided on the back side of the heating body 19.

The heating element 19b of the heating element 19 of this example is energized at a predetermined timing in response to an image forming start signal.
b generates heat over approximately its entire length. AClooV is used for energization.
The supplied power is controlled by controlling the phase angle of energization by an energization control circuit (not shown) including a triac in accordance with the temperature detected by the temperature measuring element.

The heating element 19 heats the substrate 1 by energizing the heating element 19b.
Since the heat capacity of the heating element 9a, the heating element 19b, the surface protection layer 19c, etc. as a whole is small, the temperature of the heating element surface rapidly rises to the required fixing temperature (for example, 140 to 200 DEG C.).

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

As mentioned above, the surface temperature of the film facing the heating element 19 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 period of time, resulting in excellent quick start performance. There is no need for so-called standby temperature control, in which the heating element 19 is warmed up in advance, so that energy can be saved and temperature rise inside the machine can be prevented.

The heat insulating member 20 insulates the heating element 19 to make effective use of heat generated, and is made of materials with heat insulating properties and high heat resistance, such as PPS (polyphenylene sulfide), PAI (polyamideimide), PI (polyimide), and PEEK. (
Polyetheretherketone), liquid crystal polymer, and other highly heat-resistant resins.

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

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

PC 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 pad 7o, and are synchronized with the rotation of the drum 61 by the pair of registration rollers 71. The toner images on the first side of the drum are sequentially transferred onto the second side of the fed recording material sheet.

The recording material sheet P that has passed through the transfer section 73 is separated from the surface of the drum 61 and introduced into the fixing device 100 by a guide 74.
The unfixed toner image is heat-fixed by the operation and action of the device 100 described above, and is outputted 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 and fixing device of the image forming apparatus described above, but also as an image surface heating and polishing device, a temporary fixing device, and the like.

(Effects of the Invention) As described above, according to the present invention, it is possible to eliminate the high cost of endless heat-resistant film, which is a problem in film heating type heating devices, and to provide a low-cost device. The intended purpose is well achieved.

[Brief explanation of the drawing]

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 schematic diagram of coextrusion production of an endless multilayer heat-resistant film. FIGS. 9(A) and 9(B) are a partially cutaway plan view and an enlarged cross-sectional view of the surface side of the heating body attached to the heat insulating member, respectively. FIG. 10 is a schematic configuration diagram of an example of an image forming apparatus. FIG. 11 is a schematic configuration diagram of an example of a film heating type image heating fixing device. FIG. 12 is a schematic diagram of the layer structure of an endless heat-resistant film consisting of a laminated layer of a paste layer and one surface layer. 19 is a heating body, 20 is a heat insulating member, 21 and 51 are heat-resistant films, 13 is a stay, and 10 is a roller as a rotating body. Patent applicant: Canon Co., Ltd. Kaya 6

Claims (2)

[Claims] (1) Between 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 outer surface of the film at a nip portion by sandwiching the film between the heating body and the heating body. a member for press-contacting the recording material to be heat-treated introduced into the heating body through the film, the endless heat-resistant film has a multilayer structure, and at least one layer is made of a highly heat-resistant thermoplastic resin. A heating device characterized in that it is an endless film formed by extrusion molding. (2) The endless heat-resistant film with a multilayer structure has a three-layer structure consisting of a base layer, an adhesive layer, and a surface layer in order from the inside, and it is an endless film in which these three layers are laminated by co-extrusion molding. The heating device according to claim 1, characterized in that: