JPH04204981A - heating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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, moving the heating body and the heat-resistant film relative to each other, and dissipating the heat of the heating body. A method of applying the film to the recording material through the adhesive film (
This invention relates to a heating device using a 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. An unfixed image corresponding to the desired image information formed using toner on the surface of a recording material (transfer material sheet, electrofax sheet, electrostatic recording sheet, printing paper) by an indirect (transfer) method or a direct method. An image heat fixing device that heats and fixes a toner image as a permanently fixed image on the surface of a recording material carrying the image, and 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. 83-313182.

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. The pressure member is disposed opposite to the heating member and brings the image-bearing surface of the recording material on which the image is to be fixed 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 heating means/device is basically a heating device that separates the film and recording material after passing through the fixing section at a separation point.

This kind of film heating type equipment uses a heating element that heats up quickly and a thin film, so it is possible to shorten wait time (quick start), etc.
It has the advantage of being able to solve various drawbacks of conventional devices,
It is effective.

FIG. 10 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.

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

Reference numeral 55 denotes a pressure roller as a pressure member, which holds the downward film portion of the endless held-like fixing film 51 between it and the heating body 19, and applies an unillustrated attachment to the lower surface of the heating body. The recording material sheet P is rotated in a forward counterclockwise direction 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 upper surface, conveyed from an image forming section (not shown), is guided by a guide 81 and placed between the fixing film 51 and the fixing film 51 at the pressure contact area N between the heating body 19 and the pressure roller 55. The unfixed toner image surface enters between the pressurizing roller 55 and the unfixed toner image surface is brought into close contact with the lower surface 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, and the unfixed toner image surface is stuck together with the film. The heating member 19 and the pressure roller 55 pass through the mutual pressure contact portion N in an overlapping state.

The heating element 19 is heated with electricity at a predetermined timing, and the thermal energy on the heating element 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 part 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.

The fixing film 51 is limited to the shape of an endless belt.
As shown in the example in FIG. It is also possible to adopt a configuration (film winding type) in which the sheet travels from the side to the winding shaft 83 side at the same speed as the conveyance speed of the recording material sheet P.

The heating element 19 is a heat-resistant, good thermal conductivity, insulating, and low heat capacity substrate (base material) 19a made of ceramic or the like, and a low heat capacity current-carrying heating resistor 19b as a heating element is coated in the form of a line or strip. By applying electricity to the heating element 19b, the heating element 19 has a low heat capacity, which is formed by forming the heating element 19b, the substrate 19a, and the surface protective layer 19c. temperature rises rapidly to the required fixing temperature.

The heat-resistant film 51 in contact with the heating element 19 also has a small heat capacity, and the thermal energy on the heating element 19 side is effectively transmitted to the recording material P side that is in pressure contact with the film through the film 51, thereby heating the image. Fixation is performed.

The temperature control of the heating element 19 is performed by detecting the temperature of the heating element with a temperature measuring element, and controlling the energization to the heating element 19b based on the temperature detection information to control the temperature of the heating element 19 to a predetermined fixing temperature. The composition is taken.

FIG. 12 shows a partially cutaway plan view of the side of the heating body 19 facing the heat-resistant film 51 (the surface side of the heating body).

A current-carrying heating resistor as a heating element 19b is formed into a narrow strip shape along the length of the surface of the substrate 19a, and is electrically connected to both ends of the heating element 19b to form first and second power feeding electrode portions 19d. - 19e are formed on both end surfaces of the substrate surface. The surface of the substrate has first and second power feeding electrode portions 19d on both ends.
- A surface protective layer (for example, a glass layer) 19c is formed on the entire surface except for a portion 19e.

Then, the first and second power supply connectors 30 and 31 are fitted to one end and the other end of the heating body 19, respectively, and caulked or brazed as necessary to connect the first power supply connector 30
is the first power feeding electrode portion 19d of the heating body 19, and the second power feeding connector 31 is the second power feeding electrode portion 1 of the heating body 19.
9e and are electrically connected to each other.

30a and 31a are the first and second power supply connectors 30, respectively.
・It is a power supply wire connected to 31 and connected to a power supply circuit (not shown).

As a result, the power supply circuit→Leet wire 30a→first connector 3
0 → first electrode part 19d → heating element 19b → second electrode part 19
The heating element 19b is energized through the path e→second connector 31→lead wire 31a→power supply circuit, and the heating element 19 is in a heat generating state.

(Problem to be Solved by the Invention) In the film heating type heating device as described above, there is a structure in which power is supplied to the heating element 19b of the heating element 19. Parts 19d and 19e
In the case of a configuration in which power is supplied by applying a voltage between the picture electrode parts (both-side energization type), the heat generated at both ends of the heating element 19b is transferred to the first and second electrodes on each side. 2 electrode part 1
9d/19e, connectors 30/31, lead wires 30a/
31a to the outside of the effective heating width area W of the heating element 19, and as a result, the temperature distribution within the effective heating width area W of the heating element 19 is such that even if the set temperature is reached at the center of the width, the temperature distribution at both ends of the width is On the side W and W2, an unbalanced temperature distribution state lower than the set temperature may occur, and a phenomenon may be observed where the image is insufficiently fixed at both end portions of the heat-fixed image.

Therefore, in order to compensate for the heat escaping at both ends of the heating element 19b, it is necessary to supply more power than is actually required, resulting in poor power efficiency.

In addition, in the case of such a double-sided energized type, in order to supply power to both ends of the heating element, it is necessary to route and wire long heat-resistant lead wires to connect both ends of the heating element and the power supply circuit. However, there have been problems in that the cost of an image forming apparatus using a heating device is high, and at the same time, it is difficult to assemble and service.

It is an object of the present invention to solve the above-mentioned problems by devising a configuration for feeding power to a heating element in a film heating type heating device.

(Means for Solving the Problems) The present invention brings the recording material into close contact with a heating body through a heat-resistant film, moves the heating body and the heat-resistant film relative to each other, and transfers the heat of the heating body through the heat-resistant film. In the heating device for heating the recording material, the heating body includes a heating element whose length is in the direction intersecting the direction of relative movement with the heat-resistant film and generates heat when energized, and is used for power supply to one end and the other end of the heating element. This heating device is characterized in that both electrode parts are arranged at one end of the heating body in the longitudinal direction.

Further, the present invention provides the above-mentioned heating device, wherein the heating body includes a substrate, and a surface of the substrate facing the heat-resistant film has a heat generating element whose longitudinal direction is a direction intersecting the direction of relative movement between the heating body and the heat-resistant film. A current conduction path pattern is formed on the opposite side in the same direction as the heating element, and a power feeding electrode portion is arranged at one end of the same side of the heating element and the current conduction path pattern, respectively. The heating device is characterized in that the ends are electrically connected to each other.

(Function) That is, by arranging the power supply electrode parts for both ends of the heating element at one end in the longitudinal direction of the heating element, power can be supplied from one end of the heating element where the power supply electrode parts are arranged. It can be done from the end of the side (one side energized type).

As a result, (1) At least on the heating element, on the side where the power supply electrode part is not provided, the phenomenon in which the heat generated at the end of the heating element on this side escapes through the electrode part, connector, and lead wire is eliminated, and the effective heating width area of the heating element is eliminated. There is no temperature drop in the portion of the heating element corresponding to the end of the heating element.

In other words, the temperature distribution within the effective heating width region of the heating element can be set to the set temperature except for the end region on the side where the electrode section is located, and therefore the temperature distribution of the electrode section in this effective heating width region If the recording material is transported using the end of the heating element on the side that is not connected as the recording material transport reference, there is no need to supply more power than is actually required as in the case of the double-sided energization type described above. Therefore, it is possible to perform a good fixing process on the entire surface of the recording material without causing insufficiently fixed parts, and it is also possible to improve power efficiency.

(2) Since it is a single-side energizing type, it is possible to shorten the length of the glue wire used to connect the heating element and the power supply circuit, which reduces costs and improves ease of assembly and serviceability. can.

(3) In addition, the creepage distance can be increased by configuring the heating element in such a way that the heating element is formed on the front side of the substrate (the side facing the heat-resistant film) and the current-carrying path pattern is formed on the back side. As a result, it is possible to avoid the occurrence of negative electrical and electric field effects.

(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) made of sheet metal and has an upward channel (groove) cross section; 2 and 3 are a left side wall plate and a right side wall provided integrally with the frame 1 at both left and right ends of the device frame 1; A plate 4 is an upper cover of the device, which is fitted between the upper ends of the left and right side wall plates 2 and 3, and its left and right ends are 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 long holes 6 and 7, respectively.
A pair of left and right bearing members are fitted and engaged with the lower end portions of the bearing members.

Reference numeral 10 denotes a film pressure roller (pressure contact roller, backup roller) as a rotating body which forms a nip portion by sandwiching the film between it and a heating body to be described later, and which drives the film. The left and right ends of the center shaft 11 are connected to the left and right bearing members 8, respectively.
・9 is supported by a bearing so that it can rotate freely.

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.

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. 8) which will be described later.It 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 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. It is loosely fitted onto the stay 13 including the heat insulating member 20 with a circumferential margin.

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 pair of left and right flange members 22 and 23 is set to be slightly larger than the width of the film 21.

24 and 25 are the pair of left and right flange members 22 and 23.
This is a horizontally extending lug portion 17 that protrudes outward from the outer surface of the stay 13 side.
- 18 is fully fitted into the insertion hole provided within the wall thickness of the horizontally extending lug portions 24 and 25 of the flange members 22 and 23, respectively, and the left and right flange members 22
・We 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 tension lugs 28 and 29 provided on the left and right ends of the upper cover 4 are respectively set with the coil springs 26 and 29. While compressing the coil springs 26 and 27 between the lug parts 24, 28, 25, and 29 in correspondence with the upper ends of the left and right side wall plates 2 and 3, respectively, insert the coil springs 26 and 27 into the predetermined positions between the upper ends of the left and right side wall plates 2 and 3, and then tighten the screws. 5. Fix it between the left and right 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 numeral 60 denotes a connector for supplying power to the heating element 19, which is fitted onto the end of the heat insulating member 20 protruding from the left side wall plate 2 through the elongated hole 6.

3.2 is a heated implanted logite installed on the front wall of the device frame 1, and is a recording material that supports a visible image (powder toner image) Ta as a heated material introduced into the device. A sheet P (Fig. 7) is directed between the film 21 and the pressure roller 10 at the second lug portion (heat fixing portion) N between the heating body 19 and the pressure roller 10 which are in pressure contact with the film 21 in between. I will guide you.

Reference numeral 33 denotes a heated material exit kite (separation kite) installed on the rear wall of the apparatus frame 1, and the recording material sheet that has passed through the nip portion is sent 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 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 ejection roller shaft 35 projecting outward from the is a second gear as a relay gear provided pivotably on the outer surface of the right side wall plate 3, and is a second gear G2 as a relay gear provided on the outer surface of the right side wall plate 3. G1
It meshes with the third Kia G3.

The first Kia G1 receives driving force from the drive Kia GO of a drive source mechanism (not shown), and the pressure roller 10 is rotationally driven in the counterclockwise direction in FIG. 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 entire circumference is tension-free.

When the drive is transmitted from the drive gear GO of the drive source mechanism to the first KIA 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, the pulling force f acts on the film portion upstream of the nip portion N in the film rotation direction, so that the film 2! As shown by the solid line in FIG. 7, is the inner surface of the film in the upstream side of the nip N in the direction of film rotation and near the nip, that is, the inner surface of the film of the stay 13 on which the film 21 is externally fitted. It rotates while coming into contact with substantially the lower half of the outwardly curved front plate 15 and sliding.

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, the occurrence of wrinkles at least on the film part surface, that is, the film part surface B near the recording material sheet entrance side of the nip part N, and the film part in the nip part N is prevented by the action of the tension 1. .

Then, while the film is being 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 rotated around the nip portion N while being guided by the population guide 32. Dynamic film 21 and pressure roller 10
When the recording material sheet P is introduced with the image bearing surface facing upward,
moves through the nip N together with the film 21 in close contact with the surface of 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 leaves the surface of the film 21 in a state where the toner temperature is higher than the glass transition point, is guided by the exit kite 33 between the discharge roller 34 and the punch roller 38, and is sent out of the apparatus. It will be done. Recording material sheet P
The softened/melted toner image Tb is cooled, solidified and fixed as an image Tc while leaving the nip portion N, leaving the surface of the film 21, and reaching 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 part N of its total circumference 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.
Most of the remaining part except for the entire circumference is tension-free, and during driving, tension acts only on the original nip part N and the film part B near the recording material sheet entrance side of the nip part N, and the remaining part is tension-free. 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 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),
(Figure 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 placed on one side Q in the film width direction (Figure 2) or On the other hand, even if a shift toward aR occurs, the shift force is small.

Therefore, the film 21 shifts Q or R, and its left edge or the inner flange seat 22a as the film end regulating surface of the left flange member 22, or the right edge or 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 no damage such as buckling or breakage of the film ends occurs. 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, the film deviation regulating means may include, for example, ribs made of heat-resistant resin provided at the ends of the film 21 in the circumferential direction of the endless film, and these ribs may be used to regulate the film deviation.゛Furthermore, ゛The film 21 used can reduce the rigidity by the amount of the biasing force lowered like the upper film.
Thinner walls and smaller heat capacity can be used to improve the quick start performance of the device.

(3) 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 (PEI)
・Polyether sulfone (PES) ・Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) ・Polyether ether ketone (P
EEK) - 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. A releasable coating layer containing a conductive material (carbon black, graphite, conductive whiskers, etc.) added thereto is applied to a thickness of 10 μm.

(4) Heating body 19 FIGS. 8(A) and (B) respectively show the surface side of the heating body 19 (
They are a partially cutaway plan view of the side facing the heat-resistant film 21) and a plan view of the back side.

FIG. 4(C) is a longitudinal cross-sectional view of the power insulating member 20 attached, and FIGS.

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 250 mm.

The heating element 19b is formed of, for example, Ag/Pd (silver palladium), Ta2
Made of electrically resistive material such as N, RuO2, etc., about 10 μm thick and 1 width wide.
It is coated in the form of a line or strip of ~3 mm by screen printing or the like.

One longitudinal end side of this heating element 19b (in the drawing,
A conductive pattern 19d having a relatively large area and serving as a first power feeding electrode portion is placed on the surface of the substrate on the left end side) of the heating element 1.
From the first power supply electrode part 19d, which is formed to be electrically connected to the end of this side of the heating element 19b, and for forming a through hole on the substrate surface part on the other longitudinal end side (right end side) of the heating element 19b. , is a conductive pattern 19f with a small area shape as a heating element 19
It is formed to be electrically conductive with the end of this side of b.

Further, on the back surface of the substrate 19a, a narrow strip-shaped conductive pattern 19g as a current conducting path is formed along the longitudinal direction approximately at the center of the back surface, and one length mJ (left end side in the drawing) of this current conducting path 19g is formed along the longitudinal direction. A conductive pattern 19e having a relatively large area and serving as a second power feeding electrode portion is provided on the back surface of the substrate as a conductive path 19g.
It is formed in series. Therefore, both the first and second power supply electrode parts 19d and 19e are located on the left end side of the substrate 19a, facing each other on the front and back sides of the substrate.

The other longitudinal end (right end) of the energizing path 19g and the conductive pattern 19f at this end of the heating element 19b are electrically connected to each other via a through hole 19h penetrating the thickness of the substrate 19a. It is.

Conductive pattern portions 19d-19f, 19g, 1 of the above parts
9e is formed by coating, for example, by a screen printing method, and the material is a good guiding material such as Ag (silver) or Cu (copper).
etc.

Further, the surface of the substrate 19a on which the heating element 19b, the first power feeding electrode portion 19d, and the through-hole conductive pattern 19f are formed, except for the surface portion on the left end side of the substrate where the first power feeding electrode portion 19d is present. Then, heat-resistant glass was coated to a thickness of about 10 μm as a surface protective layer 19c.

The heating body 19 having the semi-circular configuration is mounted and supported with the front side facing outward via the heat insulating member 2o on the bottom part 14 of the horizontally long stay 13 made of sheet metal as a support.

In the supported state, the left end of the heat insulating member 2o protrudes outward from the left side of the stay 13, and from the left end of the heat insulating member 2o to the left end of the heating element 19, the first and second The portion where the power feeding electrode portions 19d and 19e are formed protrudes outward.

Therefore, the power supply connector 60 is fitted to the outward protrusion of the heat insulating member 20 and the heating body 19 ((D) and (E)
figure).

The power supply connector 60 has first and second electrode plates 60d and 60e that are in pressure contact with the first and second power supply electrode parts 19d and 19e, respectively, and are electrically conductive when fitted. 1
and the second electrode plates 60d to 60e are connected to lead wires 60a, respectively.
-60b, it is connected to a power supply circuit (not shown).

As a result, the power supply circuit→Leet wire 60a→first electrode plate 60d of power supply connector 60→first electrode portion 19d of heating body 19→heating body 19b→conductive pattern 19f→through hole 19h→current conduction path 19g→second Electrode part 19e → second electrode plate 60e of power supply connector 60 → lead wire 60b
→Electrification is applied to the heating element 19b through the path of the power supply circuit, and the heating element 19 is in a heat generating state.

Although not shown in the figure, a temperature sensing element such as a low heat capacity thermistor or a low heat capacity temperature measuring resistor such as a PT film, and a safety element such as a fuse are arranged 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.

- Since the heating element 19 has a small heat capacity as a whole including the substrate 19a, the heating element 19b, and the surface protective layer 19c, the surface of the heating element 19 reaches the required fixing temperature (for example, 140 to 200°C) by energizing the heating element 19b. Temperature rises rapidly.

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 temperature of the heating element 19 is raised 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), FAI (polyamideimide), PT (polyimide), and PEEK. (
Polyetheretherketone), liquid crystal polymer, and other highly heat-resistant resins.

Therefore, as mentioned in the (effect) section above, the heating element 19
At least on the side where the power feeding electrode section 19d"196 is not provided, the heat generated at the end of the heating element on this side is transferred to the electrode section.
The phenomenon of escaping through the connector lead wire is eliminated, and the temperature drop of the heating element portion W2 (FIG. 8(C)) corresponding to the end side of the heating element within the effective width area W of the heating element 19 is eliminated.

That is, the temperature distribution within the effective heating width region W of the heating element 19 is
The area other than the end region W on the side where the electrode portions 19d and 19e are located can be kept in a set temperature distribution state, so that the effective heating width region W is recorded at the end region W on the side where the electrode portions 19d and 19e are not present. If you transport the recording material based on the material transport standard,
Without taking measures to supply more power than is actually required, as in the case of the above-mentioned double-sided energization type (Fig. 12),
Favorable fixing processing can be performed on the entire surface of the recording material without causing insufficiently fixed portions, and power efficiency can also be improved.

By being energized on one side, it is possible to shorten the length of the lead wire for communicating between the heating element 19 and the power supply circuit, and it is possible to reduce costs and improve assemblability and serviceability.゛Also, as in this embodiment, the heating element 19 has a heating element 19b on the front side of the substrate 19a (the side facing the heat-resistant film).
By forming the current conduction path pattern 19g on the back surface side, the creepage distance can be increased, and the occurrence of negative electrical and electric field effects can be avoided.

(5) Example of Image Forming Apparatus FIG. 9 shows a schematic configuration of an example of an image forming apparatus incorporating the image heating fixing apparatus 100 shown in FIGS. 1 to 8.

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 drum 61 is rotationally driven in the clockwise direction as indicated by the image forming start signal, and the surface of the rotating drum 61 or the charger 62 is rotated.
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. By performing main-scanning exposure by , an electrostatic latent image corresponding to target image information is 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. 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 onto the 82 side of the feeding 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 kite 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 then turned over and used 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.

It goes without saying that the configuration of the heating body 19 according to the present invention can also be applied to the heating body 19 of a heating device having the configuration shown in FIG. 10 or FIG. 11 described above.

(Effects of the Invention) As described above, according to the present invention, it is possible to improve power efficiency, reduce costs, and improve assembly and serviceability of film heating type heating devices. effects can be obtained, and the intended purpose can be 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. Figures 8(A) and 8(B) are a partially cutaway plan view of the front side and a plan view of the back side of the heating element, respectively, and Figure 8(C) is a longitudinal cross-sectional view of the heating element attached to the heat insulating member. (D) and (E) are an enlarged sectional view and a side view of the end portions to which power supply connectors are attached, respectively. FIG. 9 is a schematic configuration diagram of an example of an image forming apparatus. FIGS. 10 and 11 are schematic configuration diagrams of an example of a film heating type image heating fixing device, respectively. FIG. 12 is a partially cutaway plan view of the front side of the heating element of the both-side energized type. 19 is a heating body, 21 and 51 are heat-resistant films, 13 is a stay, and 10 is a roller as a rotating body. Salary 7 Figure 6 [21

Claims (2)

[Claims] (1) In a heating device in which a recording material is brought into close contact with a heating body through a heat-resistant film, the heating body and the heat-resistant film are moved relative to each other, and heat from the heating body is applied to the recording material through the heat-resistant film. includes a heating element whose length is in the direction intersecting the direction of relative movement with the heat-resistant film and which generates heat when energized, and the power feeding electrode portions for one end and the other end of the heating element are both located at one end in the longitudinal direction of the heating element. A heating device characterized in that it is located at a side end. (2) The heating element includes a substrate, and a heating element is formed on the side of the substrate opposite to the heat-resistant film, and the heating element whose length is in the direction intersecting the direction of relative movement between the heating element and the heat-resistant film, and the opposite side A conductive path pattern is formed on the side in the same direction as the heating element,
According to claim 1, each power feeding electrode portion is arranged on one end side of the heating element and the current conduction path pattern on the same side, and the other end portions are electrically connected to each other. heating device.