JPH0444075A - Heating device - Google Patents

Abstract

PURPOSE:To reduce driving torque and a film displacing force and to eliminate damage such as film breaking by placing at least part of the peripheral length of an endless heat-resisting film always in a tension-free state. CONSTITUTION:The majority of the endless heat-resisting film 21 except the part sandwiched between a heating body 19 and the nip part N of a pressure roller 10 is placed in the tension-free state when no driven. When the film 21 is driven, a drawing force (f) operates on the film part on the upstream side of the nip part N in the rotating direction of the film and then the film 21 rotates while sliding on the nearly lower half surface part of an outward accurate curve front surface plate 15 as the film internal surface guide of a stay 13. Consequently, at least a film part surface B nearby a recording material sheet entry side and the film part of the nip part N are prevented from wrinkling through the operation of the tension. Consequently, the driving force for the film is reduced and the displacing force of the film is made small to prevent a film end part from damage.

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 heat from the heating element is applied to the introduced recording material through the film by passing the heating element together with the film in close contact with the film.

This device is an image heating fixing device for image forming devices such as photocopy machines, printers, and fax machines.
That is, recording materials (transfer material sheet 1~, electrofax sheet, electrostatic recording sheet 1~・Permanently fixes an unfixed toner image corresponding to the image information of [1] to the surface of the recording material that carries the image, formed by an indirect (transfer) method or a direct method on the surface of printing paper) It can be used as an image heat fixing device that heats and fixes images.

Further, the present invention can be used, for example, in a device that heats a recording material carrying an image to modify its surface properties (polishing it), and in a device that performs temporary adhesion treatment.

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

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

For example, the present applicant has published Japanese Patent Application Laid-Open No. 6-313182.
In the above publications, a fixedly supported heating body (hereinafter referred to as heater), a heat-resistant film film that is conveyed (moving and driven) while being in pressure contact with the heater, and 1. It has a pressure member that applies the recording material to the heater through the film, and by applying the heat of the heater to the recording material through the film, an undefined image formed and carried on the surface of the recording material is formed. We have proposed an apparatus with a system and configuration that heats the surface of the recording material at a constant rate of 4+'1, 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 with the film, and the film is conveyed and introduced between the film and the pressure member at least when image fixing is performed. Approximately concave in the direction of the recording material to be fixed
By moving the recording material at a high speed and passing through a nip portion as a fixing portion formed by pressing a heater and a pressure member with the traveling film in between, the image-bearing surface of the recording material is transferred through the film. The heater heats the image (unfixed 1
・Add thermal energy to the statue! i. After softening and melting, the film and recording material after passing through the fixing section are transferred to the Official Residence 1.
It is a heating means and device that is basically turned on and left in the rain.

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

51 is a heat-resistant film in the shape of Entress Bell 1 (hereinafter referred to as 1 fixing film or simply film);
These three members 52 are parallel to each other: a drive roller 52 on the side, a driven roller 53 on the right side, and a low heat capacity linear heating element 54 disposed below between these drive rollers 52 and driven rollers 53.
・The suspension is installed between 53 and 54.

The fixing film 51 is rotated at a predetermined circumferential speed in the clockwise direction of the drive roller 52 at a predetermined circumferential speed in the 5] direction, that is, the heated film 51 carries on its upper surface an unfixed toner image Ta that is conveyed from an image forming section (not shown). It is rotated at a substantially concave circumferential speed corresponding to the transport speed (process speed) of the sheet P.

Reference numeral 55 denotes a pressure roller as a pressure section, which is biased against one surface of the heating body 54 by means of biasing means (not shown) while sandwiching the downward film portion of the endless belt-shaped fixing film 51. They are brought into pressure contact and rotated counterclockwise in the forward direction in the transport direction of the 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 (base material) 56, current-carrying heating resistor, heating element) 57 - It is composed of a surface protection layer 58, a temperature measuring element 59, etc., and is fixedly supported by being attached to a support body 61 via a heat insulating material 60.

The recording material sheet P, which has retained the unfixed toner image Ta for 1-J days and has been conveyed from an image forming section (not shown), is moved to the guide 62.
The unfixed toner enters between the fixed film 51 and the pressure roller 55 at the pressure contact portion N between the heating body 54 and the LL roller 55, and the unfixed toner image surface is conveyed at the same speed as the old recording sheet P. The heating body 5 is in close contact with the surface of the fixing film 51 which is rotating in the same direction at the same speed and in an overlapping state with the film.
4 and the pressure roller 55 pass through the mutual pressure contact portion N.

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

The rotationally driven fixing film 51 changes its running force direction at a steep angle at the edge portion S of the heat insulating material 60 having a large curvature. Therefore, the recording material sheet P conveyed through the pressure contact part N in a state overlapping with the fixing film 51 is moved sufficiently away from the fixing film 51 at the edge part S and jJF
It's being papered. By the time it reaches the tJF paper section, the TCL/toners 1 to 1 are sufficiently cooled and solidified and completely fixed on the recording material sheet P.
The situation is as follows.

(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 parallelism between the driving roller 52 and the driven roller 53 or between those rollers and the heating element 54 is out of alignment, there is always a gap between these members 52, 53, and 54 on the entire circumference. Tension is applied to the suspended film I (a very large biasing force is applied to the installed film 51 along the length 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 a thickness of less than .mu.m is used, which has originally low rigidity (weak stiffness), and since the film 51 or multiple hooks are passed between passing members 52, 53, and 54, the circumference of the film is long. As a result, the rigidity of the film 51 is low, and when such a film is moved by a very large shearing force as described above, the end of the film on the side where the shearing movement is caused becomes When pressed against a device member, the ends of the film cannot 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 balance of the film conveyance force being disrupted, the balance of pressure applied during fixing becoming unbalanced, and the temperature distribution of the heating element 19 being unbalanced. .

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 problems described in (2) by reducing driving torque and film shifting force. With the goal.

(Means for Solving the Problems) The present invention provides a heating element, an endless heat-resistant film whose inner surface is pressed against the heating element and is driven to move, and a film between the heating element and the heating element. and a member that presses a recording material supporting a microscope image to the heating body through the film, which is introduced between the outside surface of the film in the nip part and presses the recording material into contact with the heating body through the film. The heating device is characterized in that at least a part of the circumference of the heat-resistant film is always tension-free.

The present invention also provides the heating device as described above, wherein the endless heat-resistant film is in a state where the remaining circumferential portion excluding the portion sandwiched between the nip portion between the heating body and the pressure member is tension-free when the endless heat-resistant film is not driven. and during driving, tension is applied only to the nip portion and a portion between the nip portion and the inner surface guide portion of the film on the flow side of the nip portion in the direction of film movement and near the nip portion. The pressing member is in pressure contact with the heating body with the film sandwiched between them and is rotationally driven by a drive source to slide the inner surface of the film on the surface of the heating body while moving the film at a predetermined speed in the recording material conveyance direction. This heating device has the following characteristics: It is a rotating body that is driven.

(Function) (1) When the film is driven and the heating element generates heat, a visible image is formed 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 a recording material supported by the film is introduced with the image-bearing surface side facing the film, the recording material adheres to the outer surface of the film and moves through the nip section together with the film. Thermal energy of the heating body in contact with the inner surface is applied to the recording layer through the film, and the recording material supporting the visible image is heat-treated by a film heating method.

(2) By configuring the film to have a structure (tension-free type) in which 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, the above-mentioned apparatus shown in FIG. The driving torque for driving the film can be significantly reduced compared to the structure (tension type) in which a film with a long circumference is always tensioned all the way around and driven in a tensioned state. It becomes possible.

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 accuracy rough.

(3) Also, even if the film is shifted to one side or the other in the film width direction during the film driving process, the shifting force will be applied to the entire circumference of the film, as in the tension type device shown in Fig. 13. It will be much smaller than the added one.

Therefore, even if the film shifts and the end of the film on the side of the shifting side presses against the device site member on that side, the film shifting force is small, so the rigidity (strength of the film) against the shifting force increases. or fully overcome film edge damage is prevented.

Therefore, it is possible to control the shifting movement of the film by using a simple film edge regulating member such as a flange member, and it is possible to prevent large-scale shifting of the film, which includes means for detecting film shifting, returning means, etc. There is no need for a control mechanism, and in this respect as well, it is possible to simplify, downsize, and reduce the cost of the device configuration.

Furthermore, since the rigidity of the film can be reduced by the amount of the biasing force, it is possible to use a thinner film with a smaller heat capacity to improve the quick start performance of the device.

(4) When the film is not driven, most of the remaining circumference, excluding the part sandwiched between the heating element and the pressure contact member, is tension-free; when the film is driven, the film is tension-free. ( 2)・(
As mentioned in section 3), the film driving force is small and the film winding force is also small, and during this film driving, at least the surface of the film part near the recording material entrance side of the nip part and the film part of the nip part The occurrence of wrinkles on the surface is prevented by the action of the tension.

As a result, the recording material introduced into the nip portion always moves and passes through the nip portion together with the film in close contact with the wrinkle-free film surface. Therefore, uneven heating and fixing may occur due to the heated surface coming into close contact with the wrinkled film surface, or the wrinkled film may pass through the nip, resulting in the occurrence of folds on the film surface. etc. are prevented.

(5) The pressing member is a rotary member that presses against the heating body with the film in between and is rotationally driven by a drive source to slide the inner surface of the film on the surface of the heating body and drive the film to move at a predetermined speed in the recording material conveyance direction ( By using a roller body or entrespel body that performs both the functions of pressing and driving the film, it becomes possible to reduce the biasing force applied to the film, and also to reduce the position of the rotating body and the rotating body. The positional granularity of the Kia for driving can be changed, the device configuration can be simplified, the device can be made cheaper and more reliable, and the total circumference of the endless film used can be shortened. It can be done.

D6 (Embodiment) The drawing shows an embodiment of the present invention (image heat fixing device 100).
).

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

1 is a horizontally long device frame (bottom plate) made of sheet metal with an upward channel (/S) cross section; 2 and 3 are this device frame 1
A left side wall plate and a right side wall plate are attached to the frame 1 at both left and right ends of the frame 1, and 4 is the -L cover of the device, which is fitted between one end of the left and right side wall plates 2 and 3 to cover the left and right side walls. The ends are fixed to the left and right side wall plates 2 and 3 by screwing 5, respectively. screw 5
It can be removed by loosening and removing.

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

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

Reference numeral 13 denotes a laterally elongated stay made of sheet metal, which serves as an inner 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 consists of a horizontally long flat bottom part 14, a front wall plate 15 having an outward arc curve in cross section, and a front wall plate 15 which has an outward arc curve in cross section and is provided with a horizontally long flat bottom part 14, and a series of A''l slants from both long sides of the bottom part 14. It has a wall plate 16 and a pair of left and right horizontally extending lug parts 17 and 18 that project outward from both left and right ends of the bottom part 14, respectively.

Reference numeral 19 denotes a horizontally long low heat capacity linear heating element having the structure described later (Fig. 6), which is mounted and supported by the horizontally long heat insulating part old 2 degrees, and this heat insulating member 20 is oriented with the side of the heating body 19 facing F. The stay 13 is integrally mounted and supported parallel to the lower σn of the horizontally long bottom surface portion 14 of the stay 13.

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 including the heat insulating member 20=
Compared to No. 13, the circumferential length is loosely fitted.

22 and 23 connect the film 21 to the heating body 19 and heat insulating member 20
After fitting onto the stay 13 containing As will be described later, the distance G (FIG. 8) between the inner surfaces 22a and 23a of the left and right pairs of flange members 22 and 23 is slightly larger than the width C (FIG. 8) of the film 21. It is set.

24 and 25 are the left and right flange portion sides 22 and 23
The outward horizontally projecting lug parts 17 and 18 on the stay 13 side are the horizontally projecting lug parts of the flange members 22 and 23, respectively. The lug portions 24 and 25 are fully fitted into the insertion holes provided within the wall thickness, and firmly support the respective flange members 22 and 23 on the left side I〒.

To assemble the device, with the upper cover 4 removed from between the left and right side wall plates 2 and 3, the film pressure roller 10 with left and right bearing members 8 and 9 fitted in advance on the left and right ends of the support 11 is assembled.
The left and right bearing members 8 and 9 are fitted and engaged into the vertical notched elongated holes 6 and 7 of the left and right side wall plates 2 and 3 from the upper end open portions.
Insert the f-roller 10 between the left and right side wall plates 2 and 3, and pull it down to a position where the left and right bearing members 8 and 9 are received in the lower ends of the elongated holes 6 and 7 (drop-in type).

Next, the intermediate assembly, in which the stay 13, the heating body 19, the heat insulating member 20, the film 21, and the left and right flange members 22 and 23 are preassembled in the relationship shown in the figure, is placed with the heating body 19 side facing downward and insulated. The left and right outwardly projecting ends of the 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 open end part and insert it between the left and right side wall plates 2 and 3, so that the downward heating element 19 hits the "-" surface of the pressure roller 10 installed earlier with the film 21 in between. The receiver can be stopped (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 cellar vertically using the supporting protrusions provided on two sides.
-7 cover 4 is arranged so that the external force 'g elongated lug parts 28 and 29 provided on the left and right end sides of the upper cover 4 respectively correspond to the I- and ends of the coil springs 26 and 27 set above, respectively. and attach each coil spring 26, 27 to the lug part 24, 28, 25, 2.
While compressing between 9 and 9, insert left and right side wall plates 2 and 3 (1').
”: Fit it to the specified position between the ends and fix it between the left and right side wall plates 2 and 3 using screws 5.

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

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 heated material L1 guy 1- attached to the 111th wall of the apparatus frame 1, and a recording material supporting a visible image (powder toner image) Ta as a heated material introduced into the apparatus. The sheet P (Fig. 7) is guided toward the nip portion (heat fixing portion) N between the heating body 19 and the pressure roller 10 that are in pressure contact with the film 21 in between and between the film 21 and the pressure roller 10. do.

Reference numeral 33 denotes a heated ejection roller (separation guide) attached to the rear wall of the apparatus frame 1, and the recording material sheet passed through the nip section -1 is transferred to the υ1 ejection roller 34 on the G side.
and the pinch roller 38 on the L side.

The left and right (both tin) parts of the IJ outlet drawer h35 are rotatably supported between bearings 36 and 37 provided on the right side wall plates 2 and 3 of No.1. The pinch roller 38 has its hook 39 inserted into the hook part 40 formed by bending a part of the rear wall of the cover 4 inward, and then the pinch roller 38 is inserted into the hook part 40 formed by bending a part of the rear wall of the cover 4 inward.
As a result, one side of the UL output roller 34 is brought into contact with the other side.

The pinch roller 38 rotates as a result of the rotation of the υ1 output roller 34.

G1 is a roller shaft 11 that projects outward from the right side wall plate 3.
The first gear, G3, is fixed to the right side of the right side wall plate 3.
A third gear, G2, fixed to the right end of the υF output roller shaft 35 projecting outward from the υ Gear G
1 and the third Kia G3.

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

(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 from the driving Kia GO of the drive source mechanism is transmitted to the first Kia G1 and the pressure roller 1o 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. Driven for rotational movement.

In this driving state of the film 21, a pulling force f acts on the portion of the film upstream of the nip portion N in the film rotation direction, so that the film 21 moves further than the nip portion N as shown by the solid line in FIG. Contact with the inner surface guide portion of the film near the nip portion on the upstream side in the film rotation direction, that is, approximately the lower half surface portion of the outwardly curved front plate J5 serving as the inner surface guide of the stay 13 on which the film 21 is externally fitted. It rotates without sliding.

As a result, the rotating film 21 rotates with tension acting on the film portion B from the starting point 0 of the contact sliding portion with the front plate 15 to the nip portion N on the upstream side in the film rotation direction. As a result, the occurrence of wrinkles on at least the film part surface, that is, the film part surface B near the recording old sheet entrance side of the nip part N, and the film part of the nip part N can be prevented by the action of the above-mentioned tension.
be done.

Then, in a state in which the film is driven as described above and the heating element 19 is energized, the recording material sheet is guided to the input 1-1 chises 1 to 32 and carries the unfixed I/toner image Ta as a material to be heated. When the recording material sheet P is introduced between the rotary film 21 and the pressure roller 10 in the nip portion N with the image bearing surface oriented, the recording material sheets 1 to P are brought into close contact with the surface of the film 21 and the film 21
The toner image Ta is transferred to the recording material sheet P through the film, and the thermal energy of the heating element 19 that is in contact with the inner surface of the film at the nip N is applied to the recording material sheet P during the movement and passage process. This becomes a softened and fused image Tb.

The recording material sheet P that has passed through the nip portion N is separated from the film 21 surface in a state where the toner temperature is higher than the glass transition point, is guided between the ejection roller 34 and the pinch roller 38 at the output chises 1 to 33, and is removed from the apparatus. sent to. While the recording material sheet P exits the nip portion N, leaves the film 21, and reaches the discharge roller 34, the softened/melted toner image Tb is cooled, converted into an assimilated image TC, and fixed.

As described above, the recording material sheet 1-P introduced into the second lug portion N in the above-mentioned section is under tension and is always in close contact with the wrinkle-free surface of the film, so that the recording material sheet 1-P is introduced into the nip portion N.
As the film moves with the film 7.21, the wrinkled film passes through the protrusion N, causing uneven heating and uneven heating (4), which causes folds on the film surface. Don't make sushi with beef.

The film 21 has a total circumference of 0 + 1 both when being driven and when being driven.
(Although tension is applied only to N or B-N, that is, when not being driven (Fig. 6), the film 21 is tension-free over most of its entire circumference, excluding the nip portion N, and is not being driven. At the same time, tension acts only on the nip part N and the film part B near the recording material sheet entrance side of the nip part N, and most of the remaining part, approximately the entire circumference, is tension-free. Since a short length of film can be used, the driving torque required for driving the film is small, and the film device configuration, parts, and drive system configuration can be simplified, downsized, and lowered in cost.

Also, when the film 21 is driven (41-) (Fig. 6), when it is driven (
7), the tension is applied to the film 21 only on part N or B-N of the entire circumference as described above, so the film 21 is applied to one side of the film width direction in the film 7, the drive 11.1. Even if a shift occurs to the side Q (Fig. 2) or to the other force side R, the deflection force is small.

Therefore, the film is shifted by two steps Q or R, and its left edge becomes the same seat inner surface 22a as the film end regulating surface of the left flange part old 22, or the right edge or the right flange part old 23.
Even if the film is pressed against the same thickness inner surface 23a of
+1: The edges of the film should be sufficiently stamped to avoid buckling or damage. The film deviation regulating means is a simple flange member 22, 2 as in the device of this embodiment.
3 is sufficient, so even with this small size, the device configuration can be simplified, downsized, and made low cost 1, making it possible to construct a device that is inexpensive and has high reliability P1.

In addition to the flange layers 22 and 23 in the case of the device of this embodiment, as a means for regulating film deviation, for example, a rib made of heat-resistant H resin is provided at the end of the film 21 in the circumferential direction of the endless film, and this rib is controlled. It's okay.

Historically, the rigidity of the film 21 used can be lowered by reducing the biasing force as described above, so a thinner film with a smaller heat capacity can be used to improve the quick start performance of the device. It comes.

(3) Regarding film 21.

The film 21 has a small heat capacity and is
〜++1, the film thickness T of the film 21 is set to a total Jvl
Heat resistance of 20μm or more 1-+1, mold release +1, strength, durability f[
Single-layer or multi-layer films can be used.

For example, polyimide/polyetherimide (PEI)
・Polyether sulfone (PES) 4-functional ethylene-perfluoroalkyl vinyl ether copolymer resin (P
FA)・Polyetheretherketone (PEEK)
・Polyparabanic acid (PPA) or PTFE (tetrafluoroethylene resin) PAF at least on the image contact side of a 20μmN polyimide film, for example, a polyimide film.
-Fluororesin such as FEP, silicone resin, etc., and in history, a mold release coating layer with conductive materials (carbon black, graphite, conductive whiskers, etc.) added to it is 10 μmF!
I think it was done on.

(4) Regarding the heating body 19 and heat insulation part shrine 20.

The heating element 19 is similar to the heating element 54 of the apparatus shown in FIG. It consists of elements 19d and the like.

Heater↓L plate 19a has heat resistance ++1, insulation, and low heat capacity (H
H・High thermal conductivity member, for example, thickness lrnm・
It is an alumina substrate with a medium diameter of 10 mm and a length of 240 mm.

The heating element 19b is connected to one surface (film 2) of the heater substrate 19a.
1) along the longitudinal direction, for example, A.
g/' Pd (silver palladium), Ta, N, RuO2, etc., are applied in the form of lines or strips with a thickness of approximately 10 μm/[111 to 3 mm] by screen printing, etc., and a surface protective layer is applied to the first layer. Approximately 10μ of heat-resistant crow as 19c
m: 1-t.

The temperature measuring element 19d is, for example, a heater board 19ao)I-
: +'r+i It is a low heat capacity temperature measuring resistor such as a PT film provided approximately at the center of the surface (opposite to the surface on which the heating element 19b is provided) by coating by screen printing or the like. 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, which is linear or thin, is energized at a predetermined timing in response to an image formation start signal to cause the heating element 19b to generate heat over a substantially long length.

The current is supplied by AClooV, and the supplied power is controlled by controlling the phase angle at which the current is supplied by a current supply III control circuit (not shown) that controls the triac in accordance with the temperature detected by the thermometer 19c.

When the heating element 19 is energized, the heating element surface reaches a required fixing temperature (for example, 14
The temperature rises rapidly from 0 to 200°C.

The heat-resistant film 21 in contact with this heating body 19 also has a small heat capacity, and the thermal energy key on the side of the heating body 19 is in pressure contact with the film 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 is high enough to reach the melting point of the toner (or the temperature at which it can be fixed to the recording material sheet P) in a short time! Since the temperature rises to J, there is no need for so-called standby temperature control, in which the temperature of the heating element 19 is raised in advance.
It saves energy and also prevents the temperature inside the machine from rising.

The heat insulating member 20 insulates the heating element 19 to make effective use of the heat generated.
(Polyamideimide) / PI (Polyimide) / PEEK
(Polyetheretherkene)・Highly heat-resistant resin such as liquid crystal polymer.

(5) Regarding film width C and nip length.

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

That is, contrary to the above, when the film 21 is conveyed by the roller 10 with the relational configuration C20, the film conveying force (pressing force) received by the film portion within the nip length region and the portion outside the nip length DO) region are The film transport force that the film part receives is such that the inner surface of the former film part is slidably transported in contact with the surface of the heating element 19, whereas the inner surface of the latter film part is made of a different material from the surface of the heating element 19. Since it is slidably conveyed in contact with the surface of the heat insulating member 20, there is a possibility that damage such as wrinkles or folds may occur at both ends of the film 210 in the width direction due to the large difference.

On the other hand, by setting the relational structure of C<D, the surface of the heating body can be slid in contact with the inner surface of the entire length region C in the width direction of the film 21 or the surface within the length range of the heating weight 9. 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 of the surface changes. Therefore, when the length range of the heating element 19b of the heating element 19 is E, the coefficient of friction between the roller 1o and the film 21 at the portion corresponding to the length range E of the heating element 19b is:
The coefficient of friction between the roller 1o and the film 21 differs in the 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, it is possible to reduce the difference between the length range E of the heating element 19b and the film width C. 5. The difference in the coefficient of friction between the roller 10 and the film 21 affects the conveyance of the film. It is possible to reduce the impact of

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 members 22 and 23 as film end regulating means
The film end regulating surfaces 22a and 23a are the pressure roller 10.
The length is within the range of , and even if the film shifts, the edges of the film are prevented from being tampered with.

(6) Regarding the pressure roller 10.

The pressure roller 10, which forms a nip N with the film 21 sandwiched between it and the heating body 19, and serves as a rotating body for driving the film, is made of a rubber elastic body with good superplasticity, such as silicone rubber, for example. The shape is not straight in the longitudinal direction, but rather an inverted crown shape as shown in the exaggerated model diagram of Fig. 9 (A) or (B), or an inverted crown shape with the end of the inverted crown. Kall-12a
A substantially inverted crown shape is preferable.

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

That is, in the case of a straight roller, 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 is closer to the center than to the widthwise ends of the film. It could get expensive. In other words, the conveying force of the film by the rollers is greater at the center than at the ends in the width direction of the film, and as the film 21 is conveyed, a force is exerted on the film 21 that causes the portion of the film with a smaller conveying force to approach the portion of the film with a larger conveying force. , the film portion of the film edge portion 1 may move toward the center of the film, causing wrinkles on the film, and furthermore, when the recording material sheet P is introduced into the nip portion N, the recording material sheet P may be moved toward the center portion of the film. Wrinkles may occur during the transportation process.

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

The pressure roller 10 as a rotary body presses the film 21 against the heating body 19 by sandwiching the film 21 between it and the heating body 19 as in the apparatus of this embodiment, and drives the film 21 to move at a predetermined speed to When a recording material sheet P as a heated material is introduced between the film 21 and the film 21, the recording material sheet 1-P is brought into close contact with the surface of the film 21 and pressed against the heating body 19, and is driven to move together with the film 21 at a predetermined speed. By using a driving member that moves, it is possible to reduce the shifting force applied to the film, and it is also possible to improve the position of the pressure roller 10 and the positional accuracy of the roller for driving the roller.

That is, the film 21 or the film 2
The pressure function of pressurizing the film 1 and the recording material sheet P and the drive function of moving and driving the film 2 are performed by separate pressure function rotary bodies (the necessary pressure can be achieved by pressurizing this rotary body). In the case of a configuration in which the film driving function is performed by a rotating body, a large biasing force in the width direction is applied to the thin film 21 when the alignment between the heating element 19 and the film driving function rotating body is out of alignment. This may cause the edges of the film 21 to be bent, wrinkled, or otherwise damaged.

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 a push force such as a spring, check the position of the rotating body and the positional accuracy of the gear for driving the rotating body.

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 into contact with the film 21 by the pressure roller 10, which is a rotating body.
By driving the recording sheet P and the film Z1 at the same time, the above-mentioned effects can be obtained, and the configuration of the device can be simplified, making it possible to obtain a single device that is inexpensive and highly reliable. .

Incidentally, instead of the roller 10 as the rotating body, an endless held IOA which is rotationally driven as shown in FIG. 10 may be used.

(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 defined as 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 V34, it is preferable to set the speed relationship such that VIO>V34. The speed difference may be set to several percentages, for example, about 1 to 3%.

When the maximum width of the recording material sheet 1-PO) that can be introduced into the apparatus and used is F (see Figure 8),
In relation to the width dimension C, under the condition of F<C, V1
If 0≦V34, the nip portion N and the discharge roller 34
The portion of the recording material sheet P that is being conveyed astride the nip portion N is pulled by the discharge roller 34.

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

The recording material 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 roller 10, a tensile conveyance force by the discharge roller 34 is applied. In other words, the recording material sheet P and the film 21 slip at the nip portion N, and as a result, an undetermined toner image on the recording material sheet P while passing through the recording material sheet 1-P or 2 and the lug portion N. There is a possibility that the toner image Tb (FIG. 7) or the toner image Tb, which has been softened and melted, is disturbed.

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 VIO>V34, the recording material sheet 1-P and the film 21 are Since only the general feeding force of the pressure roller 10 is applied to the tension force caused by the pulling force caused by the pulling force, the slip between the sheet P and the film 21 can be prevented from causing the image blurring described above. 1 can be done.

Although the discharge roller 34 is provided on the heating device 100 side in this embodiment, it may be provided on the main body side of the image forming apparatus or the like 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 between the width of the film 21 and the method C should 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 the heat from the heating element 19, which is close to 0.degree. C., and increases in temperature C. Therefore, if the width dimension C of the film 21 at room temperature and the flange spacing method G are set to C=G, and both ends of the film 7\21 are regulated by the flange members 22 and 23, the above-mentioned film can be used when the device is in operation. Due to thermal expansion of C
> Change the state of G to 71-. The film 21 is, for example, 50μ
Since it is a thin film with a thickness of about
The film end contact pressure (end pressure) against the film 23a increases, and the film 21 cannot withstand the pressure and suffers damage such as end bending and buckling. Since the frictional force between the film edge regulating surfaces 22a and 23a of the flange portion sheaths 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 (C,
By providing C) between both ends of the film 21 and the film end regulating surfaces 22a and 23a of the flange member, both ends of the film 21 will not come into contact with the film end regulating surfaces 22a and 23a of the flange layer at the same time. .

Therefore, even if the film 21 thermally expands, the pressure contact force at the film end does not increase, so the damage at the end of the film 21 is reduced by t'
Jj lI:,: At the same time as it becomes possible to reduce the film driving force, (9) Regarding the I2 printing coefficient relationship (system) between the valley members.

a Roller (rotating body) 1 against the outer peripheral surface of the film 21
0 The friction coefficient of the surface is μm, b, the friction coefficient of the surface of the heating body 19 which is χ4 on the inner peripheral surface of the film 21 is R2, C the friction coefficient of the surface of the roller 10 that is carved on the surface of the heating body 19 is R3, d Heated material The friction coefficient of the outer circumferential surface of the filler plate λ21 with respect to the surface of the recording material sheet P is R4, e, and the friction coefficient of the surface of the roller 10 with respect to the surface of the recording material sheet 2 is R5.
, f, the maximum length τ in the conveying direction of the recording material sheet P introduced into the apparatus, U g, image transfer means when the apparatus is incorporated in a transfer type image forming apparatus as an image pre-thermal setting 71 apparatus. Assuming that the image heat fixing device is located at
, .

Therefore, the relationship between μm and R2 is μm〉R2 The relationship structure is as follows.

That is, in this type of film heating type device, the relationship between μ4 and R5 is set as R4<R5. The relationship between l and 12 is fl, I>R
2.

At this time, when μl≦μ2, the film 21 and the recording material sheet P slip in the cross-sectional direction of the heat fixing means (the conveying speed of the film 21 is delayed relative to the peripheral speed of the roller 10).
The toner image on the recording material sheet-1- 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 slower than the circumferential 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 ζ, the recorded Amako 1.S-image is also disturbed.

By setting μm>R2 as shown in 1-, the film 21 and the recording material sheet P relative to the roller 10 in the cross-sectional direction
Can prevent slipping.

Furthermore, regarding the width dimension C of the film 21, the length of the roller 10 as a rotating body/J-method H, and the length dimension of the heating body 19, under the conditions of C<H, COD, the relationship μl>R3 Configure.

That is, in the relationship of μm≦μ3, in the width direction of the heat fixing means,
The film 21 and the roller 10 slip, and as a result, the film 21 and the recording material sheet 1-P also slip, and the toner image on the recording material sheet is disturbed and distorted during heat fixing.

By configuring the relationship μm>R3 as shown in "-", it is possible to prevent the film 21 from slipping against the roller 10 in the width direction, especially on the outside of the recording surface P.

By setting μm>μ2 and μm>μ3 in this way,
The conveying speed of the film 21 and the recording material sheet P is always the same as the circumferential speed of the roller 10, so that it is possible to prevent image blurring during fixing or transfer.
By implementing 11〉μ2 and μm〉μ3 at the same time,
It becomes possible to always make the circumferential speed of the roller 10 (=process speed) and the conveying speed of the film 21 and recording material sheets 1 to P the same, and a stable fixed image can be obtained in a 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 use in controlling the film edges. The following structure is also effective as a film side edge regulating type (this is a method for dealing with the σ-shift Q-R) and a film one side edge regulating type.

In other words, the direction of the film in the width direction is always leftward Q or 2.
-For example, as in the device shown in FIG. 11, the pressing force f27 of the spring 27 on the drive side of the left and right pressurizing coil springs 26 and 27 is applied to the spring 27 on the J1 drive side so that the force is in the direction of the T force R. By setting the pressing force f26 to be higher than f26 of 26 (l27>l26), the film 21 can always be moved toward the right side R, which is the driving side. The shape of No. 10 is changed between the drive end side and the non-drive end side to control the film conveyance force so that the film always shifts in one direction, and the film edge on the shift side is A flange member serving as a regulating member for the end of the film on the side, a guide member for engaging with the film end, or the like is used to regulate the film. In other words, in the apparatus shown in FIG. By regulating the film deviation, it becomes possible to stably and easily control the deviation of the film. As a result, when the apparatus is an image heat fixing apparatus, a stable and good fixed image can always be obtained.

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

Similar effects can be obtained both in the case of a tension-type device configuration in which the film is driven by applying tension around its entire circumference, and in the case of a tension-free type device configuration like the device of this embodiment. It is possible, but the -
The L membrane structure 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 heat fixing apparatus 100 shown in FIGS. 1 to 10.

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

60 is a process car 1 to a cartridge including a rotating drum type electrophotographic photoreceptor (hereinafter referred to as a drum) 61 and a charger 6;
2. Developing device 63. Cleaning device 64 Q) This includes four process devices. 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 to open the inside of the apparatus.

The drum 61 is driven to rotate in the clockwise direction of the arrow by the image forming start signal, and the surface of the rotating tram 61 or the charger 62
A laser beam is modulated in accordance with a time-series electric digital pixel signal of image information of 1", which is charged to a predetermined polarity and potential by a drum, and outputted from a laser scanner 66 to the charged surface of the drum. 67, electrostatic latent images corresponding to image information are sequentially formed on the tram 61. The latent image is then developed into a toner image by a developing device 63.

On the other hand, the recording material sheets P in the paper feed cassette 68 are separated and fed one by one by the cooperation of the paper feed roller 69 and the separation bat 70,
It is synchronized with the rotation of the tram 61 by a pair of registration rollers 71, and is fed to a contact nip portion 73, which is a fixing portion between the tram 61 and a transfer roller 72 that is in pressure contact with the tram 61, and is then fed to the surface of the feeding recording material sheet P. Tree images of 1 to 1 side of RAM (ill) are transferred sequentially.

The recording material sheet P that has passed through the transfer JgH section 73 is transferred to the tram 611.
The fixing device 100 is separated from the fixing device 1 to 74.
The device 100 was introduced into the device 100 as described above.
75, the image is output as an image formed product (print).

The surface of the tram 61 from which the recording material sheet P has been separated after passing through the transfer section 73 is subjected to a cleaning device 64 to remove residual toner and dyed material after transfer, and is repeatedly used for image formation.

It should be noted that the heating device of the present invention is not only suitable as an image heating fixing device for the image forming apparatuses 1 to 1 described above, but can also be effectively utilized as an image surface heating polishing device, a temporary fixing device, and the like.

(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 also to reduce the shifting force of the film. It is possible to reduce the film edge damage by reducing the film edge damage, and it is also possible to make the device parts and assembly grain size rough, which allows the device configuration to be simplified, downsized, and lowered in cost.In addition, it is a device with stable ffL and reliability. becomes.

By driving the film with a pressurizing rotor, the structure of the apparatus can be further simplified and costs can be reduced.

I

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the device. Figure 2 is a longitudinal sectional view. Figure 3 is a right side view. Figure 4 is a left side view. FIG. 5 is an exploded perspective view of the main parts. FIG. 6 is an enlarged cross-sectional view of the main part showing the state of the film when not driven. FIG. 7 is the same diagram during driving. Figure 8 is a dimensional relationship diagram of component parts. 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 (3)

[Claims] (1) A fixed heating body, an endless heat-resistant film whose inner surface is pressed against the heating body and is driven to move, and the film is sandwiched between the heating body to form a nip portion, and the nip portion is formed by sandwiching the film between the heating body and the heating body. a member introduced between the outer surface of the film and the outer surface of the endless heat-resistant film for press-contacting the recording material supporting the visible image to the heating body through the film, at least a part of the circumference of the endless heat-resistant film A heating device that is always tension-free. (2) When the endless heat-resistant film is not driven, the remaining circumferential portion excluding the portion sandwiched between the heating body and the pressure member is in a tension-free state, and when it is driven, The film is characterized by a relationship in which tension is applied only to the nip portion and a portion between the nip portion and an inner surface guide portion of the film that is upstream of the nip portion in the film movement direction and near the nip portion. The heating device according to claim 1. (3) The pressure contact member is rotated by a drive source while being pressed against the heating body with the film in between, and is rotated to move the film at a predetermined speed in the recording material conveying direction while sliding the inner surface of the film on the surface of the heating body. The heating device according to claim 1, wherein the heating device is a body.