JP2917424B2 - Image heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention introduces a recording material for supporting a visible image on a surface of a heat-resistant film, which is pressed against a heating body and moved and moved, on the side opposite to the heating body side. The present invention relates to an image heating apparatus of a system (film heating system) in which heat of a heating body is applied to an introduced recording material via a film by passing the heating body together with a film through the heating body.

This apparatus is composed of an image heating and fixing device in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, etc., that is, a resin which can be heated and melted by an appropriate image forming process means such as electrophotography, electrostatic recording and magnetic recording. Recording material (transfer material sheet, electrofax sheet,
An unfixed toner image corresponding to the target image information, formed on the surface of an electrostatic recording sheet, printing paper, etc.) by the indirect (transfer) method or the direct method is permanently attached to the recording material surface carrying the image. The present invention can be used as an image heat fixing device for performing heat fixing processing as a fixed image.

Further, for example, the present invention can be used for an apparatus for improving the surface properties (such as polishing) by heating a recording material carrying an image, and for an apparatus for performing a temporary fixing treatment.

(Background Art) Conventionally, for example, a recording material heating apparatus for fixing an image by heating includes a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer and pressing against the heating roller.
2. Description of the Related Art A heat roller method of heating a recording material while nipping and conveying the recording material is often used.

In addition, various methods 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 are known.

On the other hand, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 63-313182, for example, a fixedly supported heating element (hereinafter referred to as a heater).
A heat-resistant film that is conveyed (moved and driven) while being in opposing pressure contact with the heater, and a pressing member that brings the recording material into close contact with the heater via the film. An apparatus having a method and configuration for heating and fixing an unfixed image formed and carried on the recording material surface to the recording material surface by applying the recording medium to the recording material surface has been proposed and has already been put to practical use.

More specifically, a thin heat-resistant film (or sheet), a means for driving the movement of the film, a heater fixedly supported and disposed on one side with the film in the middle, and a heater disposed on the other side A pressurizing member disposed opposite to the heater to bring a visible image bearing surface of a recording material to be image-fixed through the film into close contact with the heater, wherein the film is at least at the time of performing image fixing; Is formed by pressing the recording material to be image-fixed which is conveyed and introduced between the heater and the pressing member with the heater and the pressing member sandwiching the operation moving film in the forward direction at substantially the same speed. By passing through the nip portion as a part, the developed image carrying surface of the recording material is heated by the heater through the film to apply thermal energy to the developed image (unfixed toner image) to soften and melt the image, Then after passing through the fixing section A heating means or apparatus which is based on that to separate the film and the recording material at the separation point.

In such an apparatus of the film heating system, the use of a heating element and a thin film with a rapid rise in temperature makes it possible to shorten the weight time (quick start).
It has advantages such as being able to solve various disadvantages of the conventional device,
It is effective.

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

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

The fixing film 51 serves as a heated material carrying an unfixed toner image Ta conveyed from an image forming unit (not shown) on the upper surface at a predetermined peripheral speed in a clockwise direction accompanying the clockwise rotation of the driving roller 52. The recording material sheet P is driven to rotate at a peripheral speed substantially equal to the conveying speed (process speed) of the recording material sheet P.

Reference numeral 55 denotes a pressing roller as a pressing member, which presses the lower end of the endless belt-shaped fixing film 51 against the lower surface of the heating element 54 by pressing means (not shown). Yes, the recording material sheet P rotates counterclockwise in the forward direction in the transport direction.

The heating element 54 is a low-heat-capacity linear heating element whose longitudinal direction is the direction intersecting with the plane movement direction of the film 51 (the width direction of the film), and includes a heater substrate (base material) 56 and a current-generating heating resistor (heating element) 57. -Consists of a surface protective layer 58, a temperature sensor 59, etc.
It is fixed to and supported by a support 61 via a heat insulating material 60.

A recording material sheet P carrying an unfixed toner image Ta conveyed from an image forming unit (not shown) on the upper surface is guided by a guide 62 and is fixed to a fixing film 51 of a pressure contact portion N between a heating element 54 and a pressure roller 55. The non-fixed toner image enters the space between the pressure roller 55 and the unfixed toner image surface is brought into close contact with the lower surface of the fixing film 51 which is rotationally driven in the same direction at the same speed as the conveyance speed of the recording sheet P and overlaps with the film. In this state, it passes between the mutual press contact portions N between the heating element 54 and the pressure roller 55.

The heating element 54 is energized and heated at a predetermined timing, and the thermal energy of the heating element 54 is transmitted to the recording material sheet P in close contact with the film via the film 51, and a toner image is formed.
Ta is heated and becomes a softened / melted image Tb in the process of passing through the press-contact portion N.

The traveling direction of the rotatingly driven fixing film 51 is turned at a steep angle at the edge portion S of the heat insulating material 60 where the curvature is large. Therefore, the pressing portion N is overlapped with the fixing film 51.
Is separated from the fixing film 51 at the edge portion S by a curvature, and is discharged.
By the time the toner reaches the paper discharge section, the toner is sufficiently cooled and solidified, and is in a state of being completely fixed Tc on the recording material sheet P.

(Problems to be Solved by the Invention) Such a film heating system apparatus has the following problems as problems.

That is, in such a film heating type apparatus,
The roller for moving the film relative to the heating element is driven to rotate by a driving source while being pressed against the heating element with the film interposed therebetween, and for driving the film to move at a predetermined speed in the recording material conveying direction while sliding the inner surface of the film against the heating element surface. In the case where the roller has a general straight shape, the pressure distribution in the film width direction applied to the film by the roller at the nip portion with the heating element due to variations in component accuracy and the like is greater than the width direction end of the film. Sometimes the center was higher. In other words, the transporting force of the film by the rollers is greater at the center than at the ends in the width direction of the film. In some cases, the film portion on the side of the film edge moves toward the center portion of the film, causing wrinkles in the film.Furthermore, when the recording material sheet is introduced into the nip portion, the recording material sheet is transferred to the recording material sheet in the nip portion conveyance passage process. May cause wrinkles.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image heating apparatus which solves the above-mentioned problems in a film heating type image heating apparatus.

(Means for Solving the Problems) The present invention provides an endless film that rotates and moves,
A drive rotating member that contacts the film to drive the film, and a regulating member that contacts an end of the film to regulate a deviation in a direction perpendicular to the moving direction of the film, and the film and the drive rotation An image heating apparatus for heating an image by nipping and conveying a recording material bearing an image at a contact portion of the member, wherein the driving rotary member has a substantially inverted crown shape.

(Operation) (1) In a state where the film is driven and the heating element generates heat, the heating element and the pressure roller (the film in the nip portion formed between the driving rotating member and the pressure roller) sandwich the film. When the recording material is introduced with the visible image bearing surface side between the film side and the recording material, the recording material adheres to the outer surface of the film and moves and passes through the nip portion together with the film. The thermal energy of the heating element in contact with the inner surface of the film is applied to the recording material via the film, and the recording material supporting the visible image is heated by a film heating method.

(2) The pressing member for pressing the film against the heating element is rotated by a driving source while pressing the film across the film and is rotated by a drive source to slide the film at a predetermined speed in the recording material conveying direction while sliding the inner surface of the film against the heating element surface. By using a roller body (drive rotating member) that is moved and driven, it is possible to reduce the biasing force applied to the film, and to reduce the position of the roller body and the positional accuracy of the gear for driving the roller body. Therefore, the apparatus configuration can be simplified, the apparatus can be manufactured at low cost and high reliability, and the entire circumference of the endless film used can be reduced.

(3) By forming the pressure roller 10 in the shape of an inverted crown, the pressure distribution in the film width direction applied to the film by the roller at the nip portion with the heating element is such that the end in the width direction of the film is closer to the center. The film is conveyed while receiving a force from the center to both ends, that is, the film is conveyed while being subjected to a wrinkle elongation action, so that the film can be prevented from wrinkling and the recording introduced into the nip portion. Wrinkling of the material sheet P can be prevented.

In addition, a force acting from the central portion of the film toward both ends can reduce the biasing force of the film, and can reduce the damage received when the film comes into contact with the regulating member.

(Embodiment) The drawings show an apparatus according to an embodiment of the present invention (image heating fixing device 10).
0).

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

Reference numeral 1 denotes a horizontally long apparatus frame (bottom plate) having an upward channel (groove) in cross section made of sheet metal;
The left side wall plate and the right side wall plate integrally provided with the frame 1 at both left and right end portions thereof are upper covers of the apparatus, and are fitted between the upper end portions of the left and right side wall plates 2 and 3 so that the left and right end portions are formed. The left and right side wall plates 2 and 3 are fixed with screws 5 respectively. It can be removed by loosening the screw 5.

Reference numerals 6 and 7 denote longitudinally-notched elongated holes formed symmetrically in the substantially central surfaces of the left and right side wall plates 2 and 3, and 8 and 9 denote respective elongated holes 6.
7 is a pair of left and right bearing members fitted and engaged with the lower end of the bearing 7.

Reference numeral 10 denotes a film pressing roller (pressing roller, backup roller) serving as a rotating body (drive rotating member) that forms a nip portion with a film interposed between the heating body and a heating body, which will be described later. And a roller portion 12 made of a rubber elastic material such as silicon rubber, which has a good releasability, provided on the shaft. The left and right end portions of the center shaft 11 are rotatably mounted on the left and right bearing members 8, 9, respectively. It is supported.

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

The stay 13 has a horizontally long flat bottom portion 14 and this bottom portion.
A front wall plate 15 and a rear wall plate 16 having a cross section outwardly curved arc provided by being sequentially raised from both longitudinal sides of 14 respectively, and a pair of right and left protruding outward from both right and left ends of the bottom portion 14 respectively. It has horizontal lugs 17 and 18.

Reference numeral 19 denotes a horizontally long low-heat-capacity linear heating element having a structure to be described later (FIG. 6), which is attached to and supported by a horizontally long heat-insulating member 20. 13 is attached to and supported by the lower surface of the horizontally long bottom surface portion 14 in parallel.

21 is an endless heat-resistant film,
It is externally fitted to the stay 13 including the heat insulating member 20. The inner peripheral length of the endless heat-resistant film 21 and the outer peripheral length of the stay 13 including the heating element 19 and the heat insulating member 20 are larger than the film 21 by, for example, about 3 mm.
9. The circumference of the stay 13 including the heat insulating member 20 is loosely fitted with a margin.

22 and 23 are formed by externally fitting the film 21 to the stay 13 including the heating element 19 and the heat insulating member 20 and then fitting and supporting the horizontally protruding lugs 17 and 18 at the left and right ends of the stay 13 It is a pair of film end regulating flange members. As will be described later, the distance G (FIG. 8) between the inner surfaces 22a and 23a of the flange seats of the pair of left and right flange members 22 and 23 is
Is set slightly larger than the width dimension C (the same).

Reference numerals 24 and 25 denote horizontal overhang lugs protruding outward from the outer surfaces of the pair of left and right flange members 22 and 23, and the outward horizontal overhang lugs 17 and 18 on the stay 13 side are respectively provided by the flange members 22 and 23.・ 23 horizontal overhang lugs 24 ・ 25
It is fully fitted in the insertion hole provided in the wall thickness of the first member, and firmly supports the left and right flange members 22 and 23.

The assembling of the apparatus is carried out by removing the upper cover 4 from the space between the left and right side walls 2 and 3 and setting the left and right bearing members 8 and 9 on the left and right end portions of the shaft 11 in advance. The left and right bearing members 8 and 9 are fitted into the longitudinal notches 6 and 7 of the left and right side wall plates 2.3 and 3 from the upper end open portions, and the pressure roller 10 is inserted between the left and right side wall plates 2 and 3. The bearing members 8 and 9 are lowered to a position where they can be received by the lower ends of the elongated holes 6 and 7 (drop-down type).

Next, a stay 13, a heating body 19, a heat insulating member 20, a film
21, an intermediate assembly in which the left and right flange members 22 and 23 are pre-assembled in the relationship shown in the figure, with the heating body 19 side facing downward, and the left and right outwardly projecting ends of the heat insulating member 20 and the left and right flange members 22. The 23 horizontal overhang lugs 24 and 25 are fitted into the longitudinal cutout slots 6 and 7 of the left and right side wall plates 2.3 and 3 from the upper end open portions, and are inserted between the left and right side wall plates 2 and 3 to face downward. The heating body 19 is lowered until it is received by hitting the upper surface of the pressure roller 10 previously incorporated with the film 21 interposed therebetween (drop-down type).

Then, they protrude outside the left and right side wall plates 2 and 3 through the elongated holes 6 and 7. Lugs 24 on left and right flange members 22 and 23
・ Coil springs 26 and 27 are positioned vertically on support lugs provided on the upper surface of the lug, and set vertically, and upper cover 4 is provided on the left and right end sides of upper cover 4. Each of the coil springs 26, 27 is attached to the lug 24, with the overhang lugs 28, 29 corresponding to the upper ends of the set coil springs 26, 27, respectively.
While being compressed between 28, 25, and 29, they are fitted to a predetermined position between the upper end portions of the left and right side wall plates 2, 3 and fixed between the left and right side wall plates 2, 3 with screws 5.

As a result, the stay 13, the heating element 19, the heat insulating member 20, the film 21, and the entire left and right flange members 22 and 23 are pressed downward by the reaction force of the coil springs 26 and 27, and the heating element 19 is pressed.
The pressure roller 10 and the pressure roller 10 are held in a state in which they are pressed almost uniformly across the film 21 with a contact pressure of, for example, a total pressure of 4 to 7 kg.

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

Reference numeral 32 denotes a heated material entrance guide which is attached to the front wall of the mounting frame 1 and supports a visible image (powder toner image) Ta as a heated material to be introduced into the apparatus. (Fig.) Heating element pressed against film 21
It is guided between the roller 21 and the film 21 in the nip portion (heat fixing portion) N between the pressure roller 19 and the pressure roller 10.

Reference numeral 33 denotes a heated material outlet guide (separation guide) attached to the rear wall of the apparatus frame 1 for discharging the recording material sheet that has passed through the nip portion to a lower discharge roller 34 and an upper pinch roller 38. To the nip.

The discharge roller 34 is rotatably supported at both left and right ends of a shaft 35 between bearings 36 and 37 provided on the left and right side walls 2 and 3. The pinch roller 38 has its shaft 39 received by a hook 40 formed by bending a part of the rear wall of the upper cover 4 inward, and is brought into contact with the upper surface of the discharge roller 34 by its own weight and a pressing spring 41. The pinch roller 38 is driven to rotate by the rotation of the discharge roller 34.

G1 is a first gear fixed to the right end of the roller shaft 11 projecting outward from the right side wall plate 3, and G3 is similarly a first gear fixed to the right end of the discharge roller shaft 35 projecting outward from the right side wall plate 3. 3
The gear G2 is a second gear as a relay gear provided by being pivotally attached to the outer surface of the right side wall plate 3. The first gear G1 and the third gear G2 are provided.
Meshing with G3.

The first gear G1 receives a driving force from a driving gear G0 of a driving source mechanism (not shown), and the pressing roller 10 is driven to rotate counterclockwise in FIG. 1, and in conjunction therewith, the rotating force of the first gear G1 is reduced. The output roller 34 is transmitted to the third gear G3 via the second gear G2, and is also driven to rotate counterclockwise in FIG.

(2) Operation When the endless heat-resistant film 21 is not driven, the heating element 19 and the pressure roller as shown in FIG.
Except for the portion sandwiched between the nip portion N and the portion 10, almost the entire circumferential length of the remaining portion is tension-free (state in which tension is not applied).

When the drive is transmitted from the drive gear G0 of the drive source mechanism to the first gear G1 and the pressure roller 10 is driven to rotate in the counterclockwise direction in FIG.
Feed force is applied by the frictional force with the rotating pressure roller 10,
The endless heat-resistant film 21 is rotationally driven in the clockwise direction A while the inner surface of the film slides on the surface of the heater 19 at substantially the same rotational speed as the rotational speed of the pressure roller 10.

In the driving state of the film 21, the pulling force f acts on the film portion on the upstream side of the nip portion N in the film rotation direction, so that the film 21 is more than the nip portion N as shown by the solid line in FIG. It contacts the film inner surface guide portion near the nip portion on the upstream side in the rotation direction, that is, the substantially lower half surface portion of the outwardly curved arc front plate 15 as the film inner surface guide of the stay 13 on which the film 21 is fitted. It rotates while sliding.

As a result, the rotating film 21 rotates in a state where tension is applied to 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 downstream side in the film rotating direction. As a result, at least the film portion surface, that is, the film portion surface B near the recording material sheet entry side of the nip portion N and the film portion of the nip portion N are prevented from wrinkling by the action of the above-described tension.

Then, in the state where the above-described film drive and the energization of the heating element 19 are performed, the recording material sheet P carrying the unfixed toner image Ta as the material to be heated is guided by the entrance guide 32.
When the recording material sheet P is introduced between the rotating film 21 of the nip portion N and the pressure roller 10 in an upward direction, the recording material sheet P comes into close contact with the surface of the film 21 and moves along the nip portion N together with the film 21. The heat energy of the heating element 19 that is in contact with the inner surface of the film at the nip portion N is applied to the recording material sheet P via the film in the process of moving and passing the toner image.
Ta becomes a softened and fused image Tb.

The recording material sheet P that has passed through the nip N is separated from the surface of the film 21 with the toner temperature higher than the glass transition point, guided by the exit guide 33 between the discharge roller 34 and the pinch roller 38, and sent out of the apparatus. . The softened / fused toner image Tb is cooled and solidified while the recording material sheet P exits the nip portion N and leaves the film 21 to reach the discharge roller 34.
Tc and fix.

Recording material sheet P introduced into nip N in the above
As described above, the tension acts on the film portion surface without wrinkles, and the nip portion N moves together with the film 21 in close contact with the film portion 21. Therefore, a situation in which the wrinkled film passes through the nip portion N may occur. This causes no uneven heating and uneven fixing, and no breakage of the film surface.

The film 21 has a part N of its entire circumference both when driven and when driven.
Alternatively, since tension is applied only to BN, that is, when the film 21 is not driven (FIG. 6), the film 21 is substantially free of tension over the entire remaining portion except for the nip portion N. The tension acts only on the nip portion N and the film portion B near the recording material sheet entry side of the nip portion N, and almost the entire remaining circumferential portion is tension-free. Since a short film can be used, the driving torque required for driving the film is small, and the film device configuration, components, and drive system configuration are simplified, downsized, and reduced in cost.

When the film 21 is not driven (FIG. 6), it is also driven (FIG. 7).
As shown in the figure, since tension is applied only to a part N or BN of the entire circumferential length of the film 21 as described above, the film 21 is driven on one side Q (second
(See FIG. 2), or even if a shift to the other side R occurs, the shift force is small.

Therefore, the film 21 is shifted Q or R, and the left edge of the film 21 is pressed against the flange seat inner surface 22a as the film end regulating surface of the left flange member 22, or the right edge is pressed against the flange seat inner surface 23a of the right flange member 23. However, since the film deviating force is small, the rigidity of the film sufficiently overcomes the deviating force, and no damage such as buckling or breakage of the film end occurs. And, since the film deviation regulating means is sufficient with the simple flange members 22 and 23 as in the apparatus of the present embodiment, the apparatus configuration can be simplified, reduced in size and reduced in cost, and an inexpensive and highly reliable apparatus can be realized. Can be configured.

As the film deviation regulating means, in addition to the flange members 22 and 23 in the case of the apparatus of the present embodiment, for example, a rib made of a heat-resistant resin is provided at the end of the film 21 in the circumferential direction of the endless film, and the rib is regulated. Is also good.

Further, as the film 21 to be used, the rigidity can be reduced as much as the biasing force is reduced as described above, so that a thinner film having a smaller heat capacity can be used to improve the quick start property of the apparatus.

(3) Film 21

The film 21 has a total thickness of 100 μm in order to reduce the heat capacity and improve the quick start property.
m, preferably 40 μm or less, heat resistance of 20 μm or more.
A single layer or composite layer film having releasability, strength, durability and the like can be used.

For example, polyimide / polyetherimide (PEI)
Polyethersulfone (PES) / tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PF
A)-Polyetheretherketone (PEEK)-Polyparabanic acid (PPA), or PTFE on at least the image contacting surface side of a composite film such as a 20 µm thick polyimide film
(Tetrafluoroethylene resin), fluororesin such as PAF, FEP, etc.
Examples include a silicone resin or the like, and a release coat layer having a thickness of 10 μm to which a conductive material (carbon black, graphite, conductive whisker, etc.) is added.

(4) Heating body 19 and heat insulating member 20.

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

The heater substrate 19a is a member having heat resistance, insulation, low heat capacity, and high heat conductivity, for example, a thickness of 1 mm, a width of 10 mm, and a length of 240 mm.
mm alumina substrate.

The heating element 19b is made of an electric resistance material such as Ag / Pd (silver palladium), Ta ₂ N, or RuO ₂ along the length substantially in the center of the lower surface of the heater substrate 19a (facing the film 21). About 10
It is coated by screen printing or the like into a linear or narrow band having a thickness of 1 to 3 mm and screen coated with heat-resistant glass or the like as a surface protective layer 19c by about 10 μm.

As an example, the temperature detecting element 19d measures a low heat capacity of a Pt film or the like provided by applying a screen printing or the like to a substantially central portion of an upper surface of the heater substrate 19a (a surface opposite to a surface on which the heating element 19b is provided). It is a temperature resistor. A thermistor with a low heat capacity can also be used.

In the case of the heating element 19 of the present example, the heating element 19b having a linear or narrow band shape is energized at a predetermined timing by an image forming start signal to cause the heating element 19b to generate heat over substantially the entire length.

The power is supplied at 100 V AC, and the supplied power is controlled by controlling the phase angle to be supplied by a not-shown conduction control circuit including a triac according to the viewpoint temperature of the temperature detecting element 19c.

The heating element 19 has a small heat capacity of the heater substrate 19a, the heating element 19b, and the surface protection layer 19c due to the current supply to the heating element 19b, so that the temperature of the heating element surface rapidly rises to a required fixing temperature (for example, 140 to 200 ° C.). I do.

The heat capacity of the heat-resistant film 21 in contact with the heating element 19 is also small, and the heat energy of the heating element 19 is
The heat transfer is effectively transmitted to the recording material sheet P side in pressure contact with the film through the film, and the image is heated and fixed.

As described above, the surface temperature of the film facing the heating element 19 rises to a sufficiently high temperature relative to the melting point of the toner (or the temperature at which the toner can be fixed to the recording material sheet P) in a short time, so that quick start performance is excellent. In addition, there is no need to perform a 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 the temperature inside the apparatus can be prevented from rising.

The heat insulating member 20 insulates the heating element 19 to use heat effectively, and has heat insulating property and high heat resistance, for example, PP
High heat resistant resin such as S (polyphenylene sulfide), PAI (polyamide imide), PI (polyimide), PEEK (polyetheretherketone), liquid crystal polymer, etc.

(5) About film width C and nip length D.

As shown in the dimensional relationship diagram of FIG. 8, the width of the film 21 is C, and the length of the nip formed by pressing the heating member 19 and the pressing roller 10 as a rotating member is D with the film 21 interposed therebetween.
In this case, it is preferable to set a relational configuration of C <D.

That is, when the film 21 is conveyed by the roller 10 in the configuration of C ≧ D, the film conveyance force (pressing force) received by the film portion in the nip length D region and the nip length D out of the nip length D region are reversed. The film transport force received by the film portion of the former is that the inner surface of the former film portion is slid and transported in contact with the surface of the heating body 19, whereas the inner surface of the latter film portion is the material of the surface of the heating body 19 Because it is slid and conveyed in contact with the surface of the heat insulating member 20 of different
There is a possibility that the film 21 may be damaged at the both ends in the width direction, such as wrinkles or breakage during the film transport process.

On the other hand, by setting the relationship of C <D, the inner surface of the entire length region C in the width direction of the film 21 comes into contact with the surface within the length range D of the heating member 19 and slides on the surface of the heating member. Since the film is conveyed, the film conveying force becomes uniform in the entire length region C in the film width direction, so that the above-described trouble of the film end portion damage is avoided.

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

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

As a result, the film 21 can be driven stably by the roller 10, and damage to the edge of the film can be prevented.

The flange members 22 and 23 as the film end regulating means have the film end regulating surfaces 22a and 23a within the length range of the pressure roller 10, so that even if the film shifts, the film end is prevented from being damaged. .

(6) Pressure roller 10

A rotating body (driving rotating member) that forms a nip portion N with the film 21 interposed between the heating body 19 and drives the film.
The pressure roller 10 is made of, for example, a rubber elastic body having good releasability, such as silicone rubber, and has a shape that is longer than that of a straight shape in the longitudinal direction, as shown in FIG. The inverted crown shape as shown in the exaggerated model diagram in ()) or the substantially inverted crown shape in which the end of the inverted crown is cut 12a is preferable.

The effective length H of the roller 10 is, for example, the degree d of the inverted crown.
In the case of 230 mm, it is preferable to set d = 100 to 200 μm.

That is, in the case of the straight shape, the pressure distribution in the film width direction applied to the film 21 by the roller at the nip portion N with the heating element 19 due to the variation in the product accuracy is larger in the center portion than in the width direction end portion of the film. It could be high. In other words, the transporting force of the film by the rollers is greater at the center than at the ends in the width direction of the film, and a force acts on the film 21 such that the film portion having a smaller transporting force is directed toward the film portion having the greater transporting force. So
The film portion on the side of the film edge may move toward the center portion of the film, causing wrinkles in the film. Further, when the recording material sheet P is introduced into the nip portion N, the recording material sheet P is conveyed to the recording material sheet P. Wrinkles may occur during the passage.

On the other hand, by forming the pressure roller 10 in the shape of an inverted crown, the pressure distribution in the film width direction applied to the film 21 by the roller at the nip portion N with the heating element 19 is opposite to the above case. The widthwise end is larger than the center, whereby a force is applied to the film 21 from the center toward both ends, that is, the film 21 is conveyed while being subjected to a wrinkle elongation action, and the film wrinkles are reduced. It is possible to prevent wrinkles from occurring on the introduced recording material sheet P while preventing the occurrence of wrinkles.

The pressurizing roller 10 as a rotating body presses the film 21 against the heating body 19 with the film 21 interposed therebetween with the heating body 19 as in the apparatus of the present embodiment, and drives and moves the film 21 to a predetermined speed, When a recording material sheet P as a material to be heated is introduced between the recording material sheet 21 and the recording material sheet 21, the recording material sheet P is brought into close contact with the surface of the film 21, pressed against the heating body 19, and driven to move at a predetermined speed together with the film 21. By using the member, the biasing force applied to the film can be reduced, and the position of the roller 10 and the position accuracy of the gear for driving the roller can be improved.

That is, the pressurizing function for pressurizing the film 21 or the film 21 and the recording material sheet P against the heating body 19 and the driving function for moving and driving the film 21 are separately provided by a pressurizing function rotating body (necessary (The pressing force is obtained by pressurizing the rotating body) and the film driving function rotating body is used. If the alignment between the heating body 19 and the film driving function rotating body is out of order, the thin film is formed. A large biasing force acts on the film 21 in the width direction, and the end of the film 21 may be damaged or broken.

A heating element is added to the pressure rotating body that also serves as the film driving member.
In the case where a pressing force required for pressure contact with 19 is applied by pressing a spring or the like, the position of the rotating body and the positional accuracy of a gear for driving the rotating body are difficult.

On the other hand, as described above, the recording material sheet P is brought into pressure contact with the heating member 19 via the film 21 by applying a pressing force required for fixing to the heating member 19 by the pressing roller 10 serving as a rotating member. The above-mentioned effects can be obtained by simultaneously performing the above driving, and the configuration of the device is simplified, so that an inexpensive and highly reliable device can be obtained.

A configuration in which the roller 10 has a function of pressing the film 21 against the heating body 19 and a function of driving the film 21 is a film tension-free type apparatus such as the apparatus of the present embodiment (at least a part of the film 21 is a non-film type). A film tension type device (one in which tension is not applied during driving or film driving) or a film tension type device (a film with a long perimeter like the device in Fig. 13 described above is always tensioned over the entire circumference. To be driven)
In addition, the film deviation control means is a sensor solenoid method, a rib control method, and the film end (both sides or one side)
In any case, such as a regulation system, the same operation and effect can be obtained by applying the present invention, but it is particularly suitable for a tension-free type device.

(7) Recording material sheet discharge speed.

The conveying speed of the recording material sheet P introduced into the nip portion N as the material to be heated by the pressing roller 10 (rotary body), that is, the peripheral speed of the roller 10 is V10, and the recording material sheet discharging and conveying speed of the discharging roller 34 That is, the peripheral speed of the discharge roller 34 is V34
, It is preferable to set the speed relationship of V10> V34.
The speed difference may be set at several%, for example, about 1 to 3%.

When the maximum width dimension of the recording material sheet P that can be introduced into the apparatus and used is F (see FIG. 8), V10 ≦ V34 under the condition of F <C in relation to the width dimension C of the film 21. In such a case, the sheet portion of the recording material sheet P which is being conveyed across both the nip portion N and the discharge roller 34 is pulled by the discharge roller 34 while passing through the nip portion N.

At this time, the film 21 whose surface is coated with PTFE or the like having good releasability is conveyed at the same speed as the pressure roller 10. On the other hand, the recording material sheet P is conveyed at a speed higher than the peripheral speed of the pressure roller 10 because a pulling conveyance force by the discharge roller 34 is also applied to the recording material sheet P in addition to the conveyance force by the pressure roller 10. That is, in the nip portion N, the recording material sheet P and the film 21 slip, so that the unfixed toner image Ta (the seventh image) on the recording material sheet P while the recording material sheet P passes through the nip portion N is generated. There is a possibility that the toner image Tb in the softened / melted state may be disturbed.

Therefore, as described above, by setting the peripheral speed V10 of the pressure roller 10 and the peripheral speed V34 of the discharge roller 34 in a relationship of V10> V34, the recording material sheet P and the film 21
Since the pulling force of the discharge roller 34 does not act on the sheet P and only the conveying force of the pressure roller 10 is applied to the sheet P, it is possible to prevent the occurrence of the above-described image disorder based on the slip between the sheet P and the film 21. Can be.

In this embodiment, the discharge roller 34 is provided on the image heating apparatus 100 side, but may be provided on the image forming apparatus incorporating the image heating apparatus 100, such as an image forming apparatus.

(8) Regarding the film end regulating flange interval.

A flange seat inner surface 22a / 2 as a film edge regulating surface of a pair of left and right flange members 22/23 as film edge regulating means.
Assuming that the interval between 3a is G (FIG. 8), the film 21
In relation to the width dimension C, it is preferable to set a dimension relation of C <G. For example, if C is 230 mm, G is 1-3 mm
It is set to be large.

That is, the film 21 is, for example, 200 ° C. in the nip portion N.
The dimension C increases due to expansion due to the heat of the nearby heating element 19.
Therefore, if the width C and the distance G between the flanges of the film 21 at normal temperature are set to C = G and both ends of the film 21 are regulated by the flange members 22 and 23, the above-mentioned thermal expansion of the film during the operation of the apparatus. Produces a state of C> G. Since the film 21 is, for example, a thin film having a thickness of about 50 μm, in the state of C> G, the contact pressure (end pressure) of the flange members 22 and 23 against the film end regulating surfaces 22 a and 23 a increases. The end breaks without being able to endure it
In addition to being damaged by buckling and the like, the end of the film 21 and the flange member 22
The frictional force between the film end regulating surfaces 22a and 23a of the film 23 also increases, so that the film conveying force is reduced.

By setting the dimensional relationship of C <G, even if the film 21 expands due to heating, the gap (GC) that is larger than the expansion can be obtained.
Are provided between both end portions of the film 21 and the film end regulating surfaces 22a and 23a of the flange member, so that both end portions of the film 21 do not simultaneously contact the film end regulating surfaces 22a and 23a of the flange member.

Therefore, even if the film 21 thermally expands, the end contact pressure of the film 21 does not increase, so that the end of the film 21 can be prevented from being damaged, and the driving force of the film 21 can be reduced.

(9) Relationship of friction coefficient between each member.

a. The friction coefficient of the surface of the roller (rotary body) 10 against the outer peripheral surface of the film 21 is μ1, b. The friction coefficient of the surface of the heater 19 against the inner peripheral surface of the film 21 is μ2, c. Coefficient of friction μ
3. d. The coefficient of friction of the outer peripheral surface of the film 21 with respect to the surface of the recording material sheet P as the material to be heated is μ4, e. The friction coefficient of the surface of the roller 10 with respect to the surface of the recording material sheet P is μ5, and f. The maximum length dimension of the recording material sheet P in the transport direction is l1, g. When the apparatus is incorporated in a transfer type image forming apparatus as an image heating / fixing apparatus, the image transfer means section of the apparatus serves as an image heating / fixing apparatus. The transport path length of the recording material sheet (transfer material) P up to the nip portion N is l2.

 Thus, the relationship between μ1 and μ2 has a relationship of μ1> μ2.

That is, in this type of film heating system, the μ4
Is set to μ4 <μ5, and in the image forming apparatus, the relationship between l1 and l2 is l1> l2.

At this time, when μ1 ≦ μ2, the film 21 and the recording material sheet P slip in the cross-sectional direction of the heat fixing means (the conveyance speed of the film 21 is delayed with respect to the peripheral speed of the roller 10), and the recording material sheet Is disturbed.

Further, the recording material sheet P and the film 21 slip together (the film 21 and the recording material sheet P with respect to the peripheral speed of the roller 10).
In the case of a transfer type image forming apparatus, when the toner image is transferred onto the recording material sheet (transfer material) in the image transfer unit, the toner image on the recording material is also transferred. It will be disturbed.

By setting μ1> μ2 as described above, it is possible to prevent the film 21 and the recording material sheet P from slipping on the roller 10 in the cross-sectional direction.

Further, regarding the width dimension C of the film 21, the length dimension H of the roller 10 as a rotating body, and the length dimension D of the heating body 19,
Under the conditions of C <H and C <D, the relational configuration of μ1> μ3 is established.

That is, in the relationship of μ1 ≦ μ3, the film 21 and the roller 10 slip in the width direction of the heat fixing unit, and as a result, the film 21 and the recording material sheet P slip, and the toner image on the recording material sheet is disturbed during the heat fixing. Will be done.

With the relation of μ1> μ3 as described above, it is possible to prevent the film 21 from slipping with respect to the roller 10 in the width direction, particularly, outside the recording material sheet P.

By setting μ1> μ2 and μ1> μ3 in this manner, the transport speed of the film 21 and the recording material sheet P can always be made equal to the peripheral speed of the roller 10, and image disturbance during fixing or transfer can be prevented. Μ1> μ
2. By simultaneously executing μ1> μ3, the roller 10
And the transport speed of the film 21 and the recording material sheet P can always be the same, and a stable fixed image can be obtained in the transfer type image forming apparatus.

(10) About the film shift control.

1-9, the film shift control is performed by arranging a pair of left and right flange members 22 and 23 for regulating the film edge at both ends in the width direction with the film 21 as the center.
The following configuration is also effective as a film one-side end regulation type, in which the shift movement QR in both the left and right directions is dealt with.

That is, the drive direction of the left and right pressurizing coil springs 26 and 27 as shown in the apparatus of FIG. Spring
By setting the pressing force f27 of the film 27 to be higher than the pressing force f26 of the spring 26 on the non-drive side (f27> f26), the film 21
To control the film transport force by always moving to the right side R, which is the driving side, and by changing the shape of the heating element 19 and the shape of the roller 10 between the driving end side and the non-driving end side. The direction of the shift of the film is always in one direction, and the end of the film on the shift side is a flange member as a regulating member for the end of the film on that side, or a means such as a film rib and an engagement guide member. Regulation, that is,
In the apparatus shown in FIG. 10, by restricting only the end portion on the side R of the film 21 by the restricting member 27, it is possible to stably and easily control the film deviation. Thereby, when the apparatus is an image heating and fixing apparatus, a stable and good fixed image can be always obtained.

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

The same effect can be obtained even in the case of a tension type device configuration in which the film is tensioned and driven around the entire circumference, or in the case of a tension free type device configuration as in the present embodiment. Although possible, the arrangement is particularly suitable for tension-free types.

(11) Example of Image Forming Apparatus FIG. 11 shows a schematic configuration of an example of an image forming apparatus in which the image heating and fixing apparatus 100 of the example of FIGS.

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

Reference numeral 60 denotes a process cartridge, which includes four process devices of a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a drum) 61, a charger 62, a developing device 63, and a cleaning device 64. The process cartridge is detachably attached to and removed from a predetermined position in the apparatus by opening the opening / closing section 65 of the apparatus and opening the inside of the apparatus.

The drum 61 is rotated in the clockwise direction indicated by the arrow in response to the image formation start signal, and the surface of the rotating drum 61 is uniformly charged to a predetermined polarity and potential by the charger 62. By performing the main scanning exposure with the laser beam 67 modulated according to the time-series electric digital pixel signal of the target image information output from the target 66, the electrostatic force corresponding to the target image information on the surface of the drum 61 is obtained. Latent images are sequentially formed. The latent image is then developed 63
Is visualized as a toner image.

On the other hand, the recording material sheet P in the paper feed cassette 68 is separated and fed one by one by the cooperation of the paper feed roller 69 and the separation pad 70, and synchronized with the rotation of the drum 61 by the registration roller pair 71 so that the drum 61 Then, the toner image on the tram 1 side is sequentially transferred to the press-contact nip portion 73 which is a fixing portion of the transfer roller 72 which is in pressure contact with the transfer roller 72, and is sequentially transferred to the surface of the fed recording material sheet P.

The recording material sheet P that has passed through the transfer unit 73 is separated from the surface of the drum 61 and introduced into the fixing device 100 by the guide 74, and the unfixed toner image is heated and fixed by the operation and operation of the device 100 described above. The image is output from the outlet 75 as an image formed product (print).

Drum from which recording material sheet P is separated through transfer unit 73
The surface 61 is repeatedly used for image formation after the removal of contaminants such as transfer residual toner by a cleaning device 64.

The image heating apparatus of the present invention can be effectively used not only as the image heating fixing apparatus of the image forming apparatus of the above-described example, but also as an image surface heating polishing apparatus and a hypothetical wearing apparatus.

(Effects of the Invention) As described above, the image heating apparatus of the film heating type according to the present invention can prevent the generation of wrinkles on the film, and is a stable and reliable apparatus. By pressing and moving the film against the heating element by the pressure roller (drive rotating member), the configuration of the apparatus can be simplified and downsized, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an apparatus according to one embodiment. FIG. 2 is a longitudinal sectional view. FIG. 3 is a right side view. FIG. 4 is a left side view. FIG. 5 is an exploded perspective view of a main part. FIG. 6 is an enlarged cross-sectional view of a main part showing a film state when the film is not driven. FIG. 7 is the same as above during driving. FIG. 8 is a dimensional relation diagram of constituent members. 9 (A) and 9 (B) are exaggerated shapes showing examples of the shape of the roller 10 as a rotating body. FIG. 10 is a longitudinal sectional view of an example of an apparatus of a film one side end regulation type. FIG. 11 is a schematic configuration diagram of an example of an image forming apparatus. FIG. 12 is a schematic configuration diagram of a known example of a film heating type image heating fixing device. 19 is a heating element, 21 is an endless film, 13 is a stay, 10
Is a roller as a rotating body.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 13/20 G03G 15/20

Claims (1)

(57) [Claims] An endless film that rotates and moves;
A drive rotating member that contacts the film and drives the film, and a regulating member that contacts an end of the film to regulate a deviation in a direction perpendicular to the moving direction of the film, and the film and the drive rotation An image heating apparatus for heating an image by nipping and transporting a recording material bearing an image at a contact portion of the member, wherein the driving rotary member has a substantially inverted crown shape.