JPH0444080A - Heating device - Google Patents

Abstract

PURPOSE:To prevent damage to a film width part by providing a member which restricts the film width-directional end part to restricts the width- directional displacement of the film. CONSTITUTION:After the film 21 is fitted onto a stay 13 including a heating body 19 and a heat insulation member 20, a couple of left and right film end part restriction flange members 22 and 23 are fitted and supported on respective horizontal projection lag parts 17 and 18 of the left and right end parts of the stay 13. Consequently, even if the film 21 is displaced Q or R to have its left end edge pressed against a collar seat internal surface 22a as the film end restriction surface of the left flange member 22 or the right end edge pressed against the collar seat internal surface 23a of the right flange member 23, the film displacing force is small, so the rigidity of the film widthstands the displacing force sufficiently, so that any damage such as the buckling and breakage of the film end parts is not caused. Consequently, displacement control over the film is easily performed by the simple means and the film end part is prevented from being damaged.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention introduces a recording material that supports a visible image on the side opposite to the heating body side of a heat-resistant film that is brought into pressure contact with a heating body and driven to move. The present invention relates to a heating device of a type (film heating type) in which the heat of the heating element is introduced into the recording material through the film by passing through the heating element position together with the film in close contact with the film.

This device is an image heating fixing device in an image forming apparatus such as an electrophotographic duplexer, a printer, or a fax machine. Recording materials (transfer material sheets, electrofax sheets,
An unfixed toner image corresponding to the desired image information, formed by an indirect (transfer) method or a direct method on an electrostatic recording sheet or printing paper, is placed on the surface of the recording material carrying the image. It can be used as an image heat fixing device that heats and fixes a permanently 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) Technology) Conventionally, for example, a recording material heating device for heat-fixing an image includes a heating roller that is maintained at a predetermined temperature, and a pressure roller that has an elastic layer and presses against the heating roller. Accordingly, a heated roller method is often used in which the recording layer is heated while being held and conveyed.

In addition, various other methods are known, including a flash heating power method, an oven heating method, a hot plate heating method, a heald heating power method, and a high frequency heating method.

For example, in Japanese Patent Application Laid-Open No. 63-31:1182, the present applicant describes a fixedly supported heating body (hereinafter referred to as a heater) and a heat-resistant material that is conveyed (moving and driven) while being in pressure contact with the heater. It has a film and a pressure member that brings the recording material into close contact with the heater through the film. We have proposed an apparatus with a system and configuration that heats and fixes a printed image on the recording material surface, and have already put it into practical use.

More specifically, a thin heat-resistant film (or sheet)
a means for moving and driving the film; a heater disposed to fixedly support the film on one side of the film; The film has a pressure member that brings the image-bearing surface of the recording material on which the image is to be fixed into close contact through the image fixing member, and the film is conveyed and introduced between the film and the pressure member at least when image fixing is performed. By running the recording material at a substantially concave speed in the +++n direction and passing through a nip portion as a fixing portion formed by pressure contact between a heater and a pressure member with the moving film sandwiched therebetween. The image-bearing surface of the recording material is heated by the heater through the film to impart thermal energy to the SRR image (unspecified toner image) to soften it.
This is a heating means/device which is basically used to melt the film and separate it from the recording material after passing through the fixing section at a separation point.

This kind of film heating system has the advantage of being able to shorten wait time (quick start) because it uses a heating element with a fast temperature rise and a thin film, which solves various drawbacks of conventional equipment. and is effective.

FIG. 13 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 designates a heat-resistant film (hereinafter referred to as a fixing film or film) in the form of a heat-resistant belt, which includes a driving roller 52 on the left side, a driven roller 53 on the right side, and a film between the driving roller 52 and the driven roller 53. Mutually parallel section 3 members 52, 53, 5 of the low heat capacity linear heating element 54 arranged below
It is suspended between 4 parts.

The fixing film 51 is rotated clockwise at a predetermined circumferential speed as the driving roller 52 is rotated clockwise, that is, the fixing film 51 is rotated clockwise at a predetermined circumferential speed as the drive roller 52 rotates clockwise. Recording material sheet as heating material 1□, P
It is driven to rotate at a conveying speed (process speed) of approximately 100 mm and a substantially concave circumferential speed.

Reference numeral 55 denotes a pressure roller as a pressure member, which pinches the downward film portion of the fixing film 51 in the form of an endless belt and presses it against the seven members of the heating element 54 (not shown). The rollers are pressed against each other and rotate in one direction, which is a forward direction and a counterclockwise direction in the conveyance direction of the recording material sheet P.

The heating element 54 is a low heat capacity linear heating element whose length is in the direction (width direction of the film) that intersects the plane movement direction of the film 51, and includes a heater substrate (paste material) 56 and an energized 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 6e via a heat insulating material 60.

A recording material sheet P carrying an unfixed toner image Ta conveyed from an image forming section (not shown) is guided by chisels 1 to 62 and fixed at a pressure contact portion N between a heating member 54 and a pressure roller 55. Entering between the film 51 and the pressure roller 55,
The unfixed toner image surface is brought into close contact with the lower surface of the fixing film 51 which is rotated in four directions at the same speed as the conveyance speed of the recording material sheets 1 to P, and the heating body 54 is overlapped with the film.
and the pressure roller 55, passing between 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 2 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 the edge portion S of the heat insulating material 60 with a large surface. Therefore, the recording material sheet P conveyed through the pressure contact portion N while overlapping with the fixing film 51 separates from the fixing film 51 by the curvature at the edge portion S, and is discharged. By the time the toner is delivered to the paper ejection section, the toner has been sufficiently cooled and solidified and is completely fixed Tc on the recording material sheet P.

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

(1) In a system in which tension is constantly applied to the entire circumference of the film 51 to keep the film in tension and to drive the film, a large driving torque is required to drive the film. As a result, it is necessary to upgrade the rigidity and performance of equipment components and drive force transmission means to ensure reliability, which is a contributing factor to equipment configurations becoming more complex, larger, and more expensive. .

(2) If the alignment, such as the parallelism between the drive roller 52 and the driven roller 53 or between those rollers and the heating element 54, is out of order, the alignment between these members 52, 53, and 54 should always be maintained on the entire circumference. The film 51, which is suspended under tension, is subjected to a very large shifting force (moves) along the lengths of the members 52, 53, and 54 toward one end or the other end in the film width direction.

The film 51 has a thickness of 100 μm or less, preferably 40 μm, in order to reduce heat capacity and improve quick start performance.
A thin film with originally low rigidity (weak stiffness) of less than μm is used, and when the film 51 is hung on multiple lines, the film is passed between the transfer members 52, 53, and 54, so the circumference of the film is long. As a result, the rigidity of the film 51 is low, but when such a film is moved by a very large shifting force such as a double series, the end of the film on the side where the shifting is caused to move. If the film ends are pressed against the side device members, they will not be able to withstand the large biasing force, resulting in damage such as buckling and breakage.

Furthermore, depending on the offset position of the film 51, problems may occur, such as the film conveying force becoming unbalanced, the pressure applied during fixing being unbalanced, and the temperature distribution of the heating element 19 being unbalanced. .

Therefore, a sensor 1 that photoelectrically detects the shift of the film
A film shift control mechanism is added, which includes a means mechanism for changing the angle of a film pinch roller using a solenoid, etc. Or, if you use a heat-resistant 4'J resin rib on the edge of the film to control the ribs to control the film deviation, the device configuration will become complicated and large.・
This becomes a cause of increased costs, etc.

The present invention also belongs to the film heating method using an endless heat-resistant film, and it is an object of the present invention to provide a heating device that solves the above-mentioned problems.

(Means for Solving the Problems) The present invention provides the following features: between a fixed heating body, an en-1-less heat-resistant film whose inner surface is pressed against the heating body and is driven to move, and the heating body. a member that sandwiches the film to form a nip portion, and presses a recording material that supports a visible image to the heating body through the film, which is introduced between the film and the outer surface of the film in the nip portion; 1) When the film η is not driven, the remaining circumferential portion excluding the part sandwiched between the heating body and the pressure contact portion is tension-free; 4. The present invention also provides a heating device characterized in that it has a layer that regulates the end portions in the width direction of the film to prevent shifting of the film in the width direction. +1- When the film is driven, tension is applied only to the nip portion and a portion located upstream of the nip portion in the film movement direction and between the film inner guide portion near the nip portion and the nip portion. This heating device is characterized by having the following configuration.

(Function) (1) While the film is being driven and the heating element is generating heat, recording is made between the film and the pressing member in the nip formed between the heating element and the pressing member with the film in between. 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 together with the film. Thermal energy of the heating element is applied to the recording medium through the film, supporting the microscopic image.
The recorded recording material is then heat-treated using a film heating system 71.

(2) By configuring the film in such a manner that at least a part of the film is always tension-free (no tension is applied) both when the film is not driven and when the film is driven (tension-free type), the device shown in FIG. The drive l for driving the film is different from the structure (tension type) in which a film with a long circumference is always tensioned all around and driven in a tensioned state.
・It is possible to significantly reduce the amount of energy required.

Therefore, it is possible to simplify, downsize, and reduce the cost of the device configuration and drive system configuration, and to make the device components and assembly rough.

(3) Also, even if the film is shifted in the width direction to one side or the other side during the film driving process, the shifting force is f
This is much smaller than the tension type device shown in FIG. 13 in which tension is applied to the entire circumference of the film.

Therefore, the film shifts and shifts
Even if the end of the film is pressed against the equipment site member on that side, the film biasing force is small, so the rigidity of the film (strength of stiffness) overcomes the biasing force by 1 minute, and the taming of the film edge or prevented.

Therefore, it is possible to restrict the shifting movement of the film with a simple film end regulating member such as a flange member, and it is possible to control the film of large and small sizes, including the film shifting detection step, return movement f step, etc. There is no need for a shift control mechanism, and in this respect as well, the device configuration can be simplified, downsized, and lowered in cost.

In addition, as a film, the stiffness can be lowered to compensate for the lower biasing force.
As a result, it becomes possible to improve the quick star performance of the device by using thinner walls and smaller heat capacity.

(4) When the film is not driven, most of the remaining circumferential length, excluding the part sandwiched between the heating element and the old pressure contact part, is tension-free, and the film is driven. and a relational configuration in which tension is applied only to the nip portion and the portion between the inner surface chi 1 of the film located upstream of the nip portion in the film movement direction and near the nip portion and the nip portion. ,(2)・(
As mentioned in section 3), the film driving force is small and the film shifting force is also small, and during this film driving, at least the film part surface near the recording material entrance side of the nip part and the film part surface of the nip part The occurrence of wrinkles is prevented by the action of the tension.

As a result, the recording material introduced into the nip portion always passes through the nip portion along with the film in close contact with the wrinkle-free film surface. Therefore, the material to be heated may come into close contact with the wrinkled film surface, or the wrinkled film may pass through the nip, resulting in uneven heating and fixing, and the occurrence of creases on the film surface. Prevented.

(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.

Reference numeral 1 indicates a horizontally elongated device frame (bottom plate) made of sheet metal and has an upward channel (groove) cross section; 2 and 3 indicate a left side wall plate and a right side wall provided on the frame 1 at both left and right ends of the device frame 1; Plate 4 is the 1-cover of the device, and is fitted between the -F ends of the left and right side wall plates 2 and 3, and fixed by screwing the left and right ends to the left and right side wall plates 2 and 3, respectively. . It can be removed by loosening and removing the screw 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.
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 (press roller, backup roller) as a rotating body that pinches the film with a heating body to be described later to form a nip portion and 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 rotationally free Q bearing.

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

This stay 13 has 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 long sides of the bottom part 14.
It has a pair of left and right horizontally projecting rough 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. 6) which will be described later, and is supported by a horizontally long heat insulating member 20. The stay 13 is integrally mounted and supported in parallel with the lower surface of the oblong bottom surface portion 14 of the stay 13 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 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. Ste 1 including the heat insulating member 20
Compared to No. 3, the circumference is loosely fitted with plenty of 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 which are fitted onto the stay 13 containing the stay 13 and then fitted onto and supported by the horizontally extending lug parts 17 and 18 at the left and right ends of the stay 13. As will be described later, the spacing method G (FIG. 8) between the co-located inner surfaces 22a and 23a of the pair of left and right flange members 22 and 23 can be set slightly larger than the width dimension C of the film 21 (same). be.

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 outer surface of the stay 13 side.
7 and 18 are fully inserted into the insertion holes provided in the walls of the horizontally projecting lug portions 24 and 25 of the flange members 22 and 23, respectively, to securely hold each of the left and right flange members 22 and 23. I support it.

To finish the dark blue of the device, with the seventh cover 4 removed from between the left and right side wall plates 2 and 3, the film adding roller 1 with left and right bearing members 8 and 9 fitted in advance on the left and right end sides of the support 11 is used.
The left and right bearing members 8 and 9 of 0 are fitted into the longitudinal notched elongated holes 6 and 7 of the left and right side wall plates 2 and 3 from the open upper end, and the pressure roller 10 is moved between the left and right side wall plates 2 and 3. When the bearing members 8 and 9 on the left and right or the lower ends of the elongated holes 6 and 7 are fitted, a device that holds the receivers is lowered (drop-in type).

Next, the intermediate assembly in which the stay 13, the heating element 19, the heat insulating member 20, the film 21, and the left and right flange members 22 and 23 are assembled in the relationship shown in the figure is placed with the heating element 19 side facing downward, and The left and right outwardly projecting ends of the heat insulating member 20 and the horizontally extending lug portions 2 of the left and right flange members 22 and 23
4 and 25 into the vertical notch slots 6 of the left and right side wall plates 2 and 3, respectively.
- Fit and engage 7 from the upper end open part and insert it between the left and right side wall plates 2 and 3, and the receiver stops when it hits the upper surface of the pressure roller 10 installed earlier with the downward facing heating element 19 or film 21 in between. (drop-in type).

Then, coil springs 26 and 27 are attached to the lug portions 24 and 25 of the left and right flange members 22 and 23, respectively, which protrude through the elongated holes 6 and 7 to the outside of the left and right side wall plates 2 and 3.
Position the support protrusion provided on one side and set it vertically, and place the Seven Cover 4 on the left side of the Tokahar 4! The outwardly protruding lug parts 28 and 29 provided on the f end side are made to correspond to the upper ends of the coil springs 26 and 27 set above, respectively, so that each coil spring 26 and 27 is connected between the lug parts 24, 28, 25, and 29. Rather than compressing it, insert it into the predetermined position between the upper ends of the left and right side wall plates 2 and 3 and screw 5 to 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 are pressed in the F direction, and the heating body 19 and the roller 10 or the film 21 are sandwiched in between and the longitudinal parts are brought into contact with each other approximately equally with a contact pressure of, for example, 4 to 7 kg in total. Retained.

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

Reference numeral 32 denotes a recording material sheet P, which is attached to the front wall of the apparatus frame 1 and has a heating guide [1 guide, and which supports a visible image (powder toner image) Ta as a heated material introduced into the apparatus. (FIG. 7) is guided toward the gap between the film 21 and the roller 10 at the nip (heat fixing section) N between the heating body 19 and the roller 0 that are in pressure contact with the film 21 in between.

Reference numeral 33 denotes a heated punching roller (separation guide) attached to the rear wall of the apparatus frame 1, which transfers the recording material sheet that has passed through the nip section to the F-side discharge roller 34 and the upper pinch roller 38. guide to the nip part.

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 shaft 39 of the donjikoro 38 has a hook portion 40 formed by bending a part of the rear wall of the upper cover 4 inward.
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 the discharge roller 34 rotates.

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
It meshes with the third Kia 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 direction of force M counterclockwise in FIG. The force 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 is moved clockwise A while sliding on the inner surface of the film or 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 the part of the film on the flow side in the film rotation direction with respect to the nip part N, so that the film 21 is moved to the nip part N as shown by the solid line in FIG. For the inner surface guide portion of the film located upstream in the film rotation direction and near the nip, that is, approximately the lower half surface portion of the outwardly curved front plate 15 serving as the inner surface guide of the stay 13 on which the film 21 is externally fitted. It contacts and rotates while 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 portion N on the upstream 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 being driven as described 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 rotated in the nip portion N by being guided by the inlet rockide 32. 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 film 21 and moves through the nip part N together with the film 21, and during the movement and passage process, the thermal energy of the heating element 19 in contact with the inner surface of the film in the nip part N is absorbed 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 surface of the film 21 in a state where the toner temperature is higher than the glass transition point and comes out]. Sent out. The recording material sheet P exits the nip part N and moves away from the film 21 side.
The toner image Tb softens and melts while reaching the output roller 34.
is cooled, assimilated into TC, and fixed.

” 2, the recording material sheet P introduced into the nip portion N
As mentioned above, the film 21 is under tension and always comes into close contact with the surface of the unwrinkled film portion and moves through the nip N together with the film 21, so there is a possibility that the wrinkled film may pass through the nip N. No heating unevenness or fixing unevenness caused by the film, and 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 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 at 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 in the film width direction (Figure 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 end edge or the same seat inner surface 22a as the film end regulating surface of the incoming 1 flange member 22, or its right end edge or the right side flange member 2.
Even if the film is pressed against the inner surface 23a of the seat 3, the film's biasing force is small, so the rigidity of the film overcomes the biasing force and the edge of the film does not buckle or break. . In addition, since the means for regulating the deviation of the film only needs to be the simple flange members 22 and 23 as in the device of this embodiment, the device configuration can be simplified, downsized, and lowered in cost, making it inexpensive and highly reliable. Can configure devices.

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) Regarding film 21.

In order to improve the quick start property by reducing the heat capacity of the film 21, the IIU W T of the film 21 is ld, H10 um or less, preferably H40 μm or less, 2
A single layer or composite layer film having heat resistance, mold releasability, strength, durability, etc. of 0 μm or more can be used.

For example, polyimide polyetherimide (PEI)
・Polyether sulfone (PES) 4-functional ethylene-perfluoroalkyl vinyl ether copolymer resin (
PFA)/Polyetheretherketone (PEEK)
- Polyparabanic acid (PPA) or PTFE (tetrafluoroethylene resin) PA at least on the image contact side of a composite layer film, such as a 20 μm thick polyimide film.
A releasable coating layer made of a fluororesin such as F-FEP, a silicone resin, etc., and a conductive material (carphone fluff, graphite, conductive whisker, etc.) added thereto is applied to a thickness of 10 μm.

(4) Regarding the heating element 19 and insulation part 20.

The heating element 19, similar to the heating element 54 of the apparatus shown in FIG. 13, includes a heater substrate 19a (see FIG. 6), an energized heating resistor (heating element) 19b, a surface protection layer 19c, a temperature measuring element 19d, and the like.

The heater board 19a has heat resistance, insulation, low heat capacity, and high thermal conductivity, 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
/ Pd (silver palladium), Ta2N, RuO2, or other electrically resistive material is coated in the form of a line or strip with a thickness of about 10 μm/[1] 1 to 3 mm by screen printing or the like, and a heat-resistant layer 19c is applied thereon as a surface protective layer. It is coated with glass to a thickness of about 10 μm. For example, the temperature sensing element 19d is made of a low heat capacity material such as a PT film, which is coated by screen printing or the like on the approximate center of the L surface (the surface opposite to the surface on which the heating element 19b is provided) of the heater substrate 19a. It is a resistance temperature sensor.

It can also be used with low heat capacity thermistors.

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 cause the heating element 19b to generate heat over substantially its entire length.

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.

When the heating element 19 is energized, the heater substrate 19a, the heating element 19b, and the surface protection layer 19c have a small heat capacity, so that the surface of the heating element reaches the required fixing temperature (for example, 14
The temperature rises rapidly from 0 to 200°C.

The heat-resistant film 21 in contact with the heating element 19 also has a small heat capacity, and the recording material sheet 2 in a pressure-contact state with the film is generated by the thermal energy of the heating element 19 via 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 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 preheated, energy can be saved, 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 the heat generated, and has heat insulating properties and high heat resistance, such as pps (to polyphenylene sulfite 1) and PAT (
Polyamideimide) / PI (Polyimide) / PEEK
(polyetheretherketone), liquid crystal polymer, and other highly heat-resistant resins.

(5) Regarding film width C and nip length.

Dimension tj = As shown in the relationship diagram in FIG. 8, the width of the film 21 is C, and the length of the nip formed by pressure contact between the heating body 19 and the pressure roller 10 as a rotating body with the film 21 in between. In this case, it is preferable to set the relational configuration such that C<D.

In other words, when the film 21 is conveyed by the roller 10 with the relationship C20, contrary to the above, 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 latter film portion is transported by sliding motion in contact with the surface of the heating member 19, while the inner surface of the latter film portion is of a material different from the surface of the heating member 19. Different insulation members 20
Since the film 21 is conveyed slidingly in contact with the surface of the film 21, there is a possibility that damage such as wrinkles or folds may occur at both ends of the film 21 in the width direction during the film conveyance process.

By engraving this and setting the relational structure of C<D, the inner surface of the entire length region C in the width direction of the film 210 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 the length range dimension of the heating element 19b of the heating element 19 is E, the friction coefficient between the roller 10 and the film 21 at the portion corresponding to the length range E of the heating element 19b,
The coefficient of friction between the roller 10 and the film 21 differs in a portion corresponding to the outside of the length range E of the heating element 19b.

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 allows the film 21 to be stably driven by the roller 10, making it possible to prevent damage to the edges of the film.

Flange layer 22 and 23 as film edge 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, the edges of the film are prevented from being damaged.

(6) Regarding pressure roller 0.

The pressure roller 10, which forms a nip N by sandwiching the film 21 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) than the straight shape in the long hair direction.
) as shown in the exaggerated model diagram, or a substantially inverted crown shape with cuts 1 to 12a at the ends of the inverted crown shape.

When the effective length H of the roller 10 is, for example, 230 mm, the degree d of the inverted crown may be set to d - 100 to 200 μm.

In other words, in the case of a straight shape, due to variations in component precision, etc., 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 may be closer to the center than to the ends in the width direction. It could get expensive. In other words, the conveying force of the film by the rollers is greater at the center than at the edges 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 lean toward the portion of the film with a larger conveying force. , the edge of the film may move toward the center of the film, causing wrinkles in the film.Furthermore, when a recording material sheet P is introduced into the nip portion N, the recording material sheet P may be nipped. Wrinkles may occur during the passage of the portion Wj.

On the other hand, by forming the 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 reversed in the film width direction. The edges are larger than the center, which makes the film 21
The film 21 is conveyed by a force acting from the center toward both ends, that is, while being subjected to the effect of smoothing out wrinkles, making it possible to prevent wrinkles on the film and also to prevent wrinkles on the introduced recording material sheet P. It is.

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 also moves and drives the film 21 at a predetermined speed to remove the film. When a recording material sheet P as a heated material is introduced between the film 21 and the film 21, the recording material sheet P is layered on the surface of the film 21, is brought into pressure contact with the heating body 19, and is driven to move together with the film 21 at a predetermined speed. By using it as a driving member, it is possible to reduce the shifting force applied to the film, and it is also possible to improve the positional accuracy of the roller 10 and the gear for driving the roller.

That is, the film 21 or the film 2
1 and the recording material sheet P, and a drive function to move and drive the film 21, are provided by separate pressurizing rotary bodies (the necessary pressurizing force is obtained by pressurizing these rotary bodies). ) and a film drive function rotating body, if the alignment between the heating element 19 and the film drive function rotary body goes out of alignment, the thin film 21 will be subjected to a large biasing force in the width direction. As a result, the edges of the film 21 may be damaged, such as folds or wrinkles.

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 springs or the like, the position of the rotating body and the positional granularity of the gear for driving the rotating body should be checked.

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 1o, the rotating body may be an endless heald IOA that is rotationally driven as shown in FIG.

The configuration in which the rotary body 10/IOA has the function of bringing the film 21 into pressure contact with the heating body 19 and the function of driving the film 21 is suitable for a film tension-free type device (at least part of the film 21) like the device of this embodiment. is a device in which no tension is applied both when the film is not being driven and when the film is being driven), a film tension type device (such as the device shown in Fig. 13 above, which always applies tension all the way around a long film) There are also film deviation control means, sensor/solenoid method, rib control method, film edge control method (
The same action and effect can be obtained by applying the method to both sides or one side), and it is particularly suitable for application to a tension-free type device configuration.

(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 VIO, 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, the speed relationship may be set such that V10>VB2. The speed difference may be set to several percentages, for example, about 1 to 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 210, the condition t of F<C is VIO≦V3.
4, the recording material sheet 1 is being conveyed astride between the nip portion N and the discharge roller 34.
~P, the sheet portion passing through the nip portion N is lengthened by the υ ejection roller 34.

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

Hoki 82. ) The rA sheet P is conveyed at a speed faster than the circumferential speed of the pressure roller 10 because, in addition to the conveyance force by the pressure roller 10, a tensile conveyance force by the υF output roller 34 is applied. In other words, at the nip portion N, recording material sheets 1 to P
This causes the film 21 to slip, and as a result, while the recording material sheet P is passing through the nip portion N, the unfixed toner image Ta (FIG. 7) on the recording material sheet P becomes soft or melted. This may cause disturbance in the toner image Tb.

Therefore, as described above, by setting the circumferential speed VIO of the pressure roller 10 and the circumferential speed V34 of the discharge roller 34 in the relationship of VIO>VB2, the recording material sheet P and the film 2
1 is given only the conveying force of the pressure roller 10 which acts on the sheet P by the tensile force of the discharge roller 34,
It is possible to prevent the above-mentioned image disturbance from occurring due to slippage between the sheet 1-P and the film 21.

In this embodiment, the discharge roller 34 may be provided on the side of the heating device 100, or may be provided on the side of the main unit, such as an image forming apparatus into which the heating device 100 is incorporated.

(8) Regarding the film edge regulation flange spacing.

The inner surface 22 of the pair of left and right flange members 22 and 23 as film end regulating means serves as a film end regulating surface.
When the distance between a and 23a is G (FIG. 8), the relationship with the width C of the film 21 may be set such that C<G. For example, when C is set to 230 mm, G is set approximately 1 to 3 mm larger.

That is, the film 21 has a thickness of, for example, 200 at the nip portion N.
It expands upon receiving heat from the heating body 19 at a temperature close to 0.degree. C., and its dimension C increases. Therefore, if the width dimension C of the film 21 and the flange interval dimension G at room temperature are set to C=G, and both ends of the film 21 are regulated by the flange members 22 and 23, the thermal expansion of the film described above occurs when the device is in operation. By CO
produces the state of G. Since the film 2I is a thin film of about 50 μm, for example, in the state of C>G, the film end regulating surfaces 22a and 23a of the flange members 22 and 23
The end contact pressure (end pressure) of the film 21 increases, and the film 21 cannot withstand this pressure and suffers damage such as end bending and buckling. Since the frictional force between the film end regulating surfaces 22a and 23a of the flange members 22 and 23 also increases, the film conveyance force also decreases.

By setting the dimensional relationship C<G, even if the film 21 expands due to heating, the gap (G-C
) is provided between both ends of the film 210 and the film end regulating surfaces 22a and 23a of the flange member, thereby preventing both ends of the film 21 from coming into contact with the film end regulating surfaces 22a and 23a of the flange member at the same time.

Therefore, even if the film 21 expands thermally, the film end pressure contact force does not increase, which prevents the end of the film 21 from being damaged.
In addition to making it possible to perform 1-d printing, the film driving force can also be reduced.

(9) Regarding the friction coefficient relationship between each member.

a, roller (rotating body) 1 against the outer peripheral surface of the film 21
0 the friction coefficient of the surface is μl, b, the friction coefficient of the heating body 19 surface against the inner peripheral surface of the film 2J is μ2, C1 the friction coefficient of the roller 10 surface against the heating body 19 surface is μ3, d5 Record as heated material! The rl-MA coefficient of the outer peripheral surface of the film 21 with respect to the surface of the 4-sheet P is μ4, e, and the friction coefficient of the surface of the roller 1o with respect to the surface of the recording material sheet 2 is μ.
5. f, fit the maximum length in the transport direction of the recording material sheet P introduced into the device; What is the conveyance path length of the recording material sheet (transfer material) P to the nip portion N of the image heat fixing device? 2.

Therefore, the relationship between μm and μ2 is μl〉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 11 and vertical 2 is set as fit > u2.
It becomes.

At this time, when μm≦μ2, the film 21 and the recording material sheet P slip in the cross-sectional direction of the heat fixing means (the transport speed of the film 21 lags behind the circumferential speed of the roller 10).
The toner image on recording material sheet 7 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 sheet is also disturbed.

By setting μm>μ2 as shown in -F, the film 21 and the recording material sheet P relative to the roller 10 in the cross-sectional direction
can prevent slipping.

In addition, regarding the width C of the film 21 and the length of the roller 10 as a rotating body; Make it a relational structure.

That is, in the relationship of 111≦μ3, the film 21 and the roller 1o slip in the width direction of the heat fixing means, and as a result, the film 21 and the recording material sheet 1-P slip, and the toner on the recording material sheet during heat fixing. The image is distorted.

By configuring the relationship μm>μ3 as shown in 1-, 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.

In this way, by setting μm>μl, μl>μ3,
The conveying speed of the film 21 and the recording material sheet P should always be the same as the peripheral speed of the roller 10, which can prevent image disturbances during fixing or transfer, and μ
By performing m>μl and μm>μ3 at the same time, the circumferential speed of the roller 10 (-process) and the film 2
By always keeping the conveying speed of the recording material sheet 1 and the recording material sheet 1-P the same, it becomes possible to obtain a stable fixed image in the transfer type image forming apparatus.

(10) Regarding film shift control.

The film shift control of the embodiment apparatus shown in FIGS. 1 to 10 is performed by disposing a pair of left and right flange members 22 and 23 on both ends of the film 21 in the width direction for controlling the ends of the film. The following configuration is also effective as a method to deal with the deviation movement QR of the film (film both-side edge restriction type) or a film one-side edge restriction type.

In other words, the driving side of the left and right pressure coil springs 26 and 27 is set so that the direction in which the film is shifted in the width direction is always either leftward Q or rightward R. By setting the pressing force f27 of the spring 27 to be higher than the pressing force f26 of the spring 26 on the non-driving side (f27>f26), the film 21 is always moved toward the right side R, which is the driving side. In addition, by changing the shape of the heating element 19 and the shape of the roller 1o on the driving end side and the non-driving end side, the film conveying force can be controlled so that the shifting direction of the film is always in one direction. The end of the film on the closer side is regulated by means such as a flange member serving as a regulating member for the end of the film on that side, a film rib and an engaging guide member, etc. In other words, in the apparatus shown in FIG. By regulating only the edge of the film 21 on the side R using the regulating member 27, it becomes possible to stably and easily control the film deviation. As a result, when the apparatus is an image heat fixing apparatus, a stable and good fixed image can always be obtained.

Furthermore, since the endless film 21 is driven by the pressure roller 10 forming the nip portion N, no special driving roller is required.

These effects can be obtained both in the case of a tension-type device configuration in which the film is driven by applying tension all around it, and in the case of a tension-free type device configuration like the device of this embodiment. The construction of the means is particularly suitable for tension-free types.

(11) Example of Image Forming Apparatus FIG. 12 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.

Reference numeral 60 denotes a process car 1 to a cartridge, including a rotating drum type electrophotographic photoreceptor (hereinafter referred to as a drum) 61 and a charger 6.
It includes four process devices: 2, a developing device 63, and a cleaning device M64. 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 driven to rotate in the clockwise direction of the arrow by the image forming start signal, and the surface of the rotating drum 61 or the charger 62 is rotated.
The charged surface of the drum is charged to a predetermined polarity and potential by a laser beam 67 modulated in accordance with a time-series electric digital pixel signal of the target image information output from a laser scanner 66. By performing main scanning exposure, an electrostatic latent image corresponding to target image information is sequentially formed on the surface of the drum 61. The latent image is then converted into a W1 image as 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 70, and are synchronized with the rotation of the tram 61 by a pair of registration rollers 71, and then 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 first side of the drum is sequentially transferred onto the surface of the fed recording material sheet P.

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 heated and 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 adhering contaminants such as untransferred trees by a cleaning device 64, and is used repeatedly for image formation.

The heating device of the present invention is not only suitable as an image heating and fixing device for the image forming apparatus described above, but also can be effectively used as an image surface heating and polishing device.

(Effects of the Invention) As described above, since the heating device of the film heating method of the present invention has a tension-free type structure for the film, it is possible to reduce the driving force of the film, and the shifting force of the film. By making the film smaller, it is possible to control the deviation of the film well with a simple film end regulating means such as a flange member, and it is also possible to prevent film end tampering, which also prevents roughness in equipment parts and assembly accuracy. The device configuration can be simplified, downsized, and lowered in cost, and 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. Figure 7 is the same figure when driving. FIG. 8 is a dimensional relationship diagram of the constituent members. Figures 9(A) and 9(B) each show the roller 1 as a rotating body.
An exaggerated shape diagram showing an example of the shape of 0. FIG. 10 is a diagram showing an example in which a rotating belt is used as the rotating body. FIG. 11 is a longitudinal cross-sectional view of an example of a device that regulates one end of the film. FIG. 12 is a schematic configuration diagram of an example of an image forming apparatus. FIG. 13 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 (2)

[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 in the section and a member that presses a recording material supporting a visible image to the heating body through the film, and the film is in contact with the heating body and the pressing member when not driven. The remaining circumferential portion excluding the portion sandwiched in the nip portion of the film is tension-free, and the end portion in the width direction of the film perpendicular to the moving direction of the film is restricted to restrict shifting of the film in the width direction. A heating device characterized by having a member. (2) 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.