JP2000188170A - Heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of a heating body when a very thick paper sheet is fed or a recording material is duplicately fed by fitting the heating body into the heating body fitting groove of a heating body support, holding it in contact with a groove bottom section, and arranging a height adjusting pattern adjusting the contact areas between the heating body and the support or the height of the film sliding face of the heating body and the film sliding face of the support on a contact face. SOLUTION: A height adjusting pattern 60 with nearly the same structure as that of the conductive patterns 22, 23 of a temperature detecting element 24 is arranged on a heating body 1, the contact areas between the heating body 1 and a heating body support 2 on the right and left in the longitudinal direction of an exothermic resistor 12 are made nearly equal, thus the fixing property on the right and left in the longitudinal direction is made nearly homogeneous. Locally overheated heat is dispersed in the longitudinal direction along the conductive patterns 22, 23 and the height adjusting pattern 60 and is radiated to the heating body support 2, thus overheating is reduced, and the breakage of the heating body 1 at the end section of a recording material when a thick paper sheet is fed or at the time of a duplicated feed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a heating apparatus and an image forming apparatus. Particularly, in an image forming apparatus using an electrophotographic method, such as a copying machine or a printer, it relates to a heating device used for permanently fixing a toner image to a recording material. The present invention relates to a film heating type heating device in which a recording material is brought into close contact with a heating body whose temperature is controlled via a heat-resistant film to apply thermal energy of the heating body to the recording material.

[0002]

2. Description of the Related Art As a heating device represented by a fixing device for heating a toner image in an electrophotographic process and fixing the toner image on a recording material, a contact heating method such as a heat roller method or a film heating method has been widely used. Have been. In such a device, an electric current flows through a halogen lamp or a heating resistor to generate heat, and the fixing roller or a fixing film is used to generate heat.
The toner image is being heated.

However, the heating device of the heat roller type requires a considerable waiting time (wait time) from when the power is turned on to when the fixing roller rises to a predetermined temperature because the heat capacity of the fixing roller is large. Even after the temperature rises, it is necessary to control the heat source (halogen lamp, etc.) of the fixing roller to keep the fixing roller temperature constantly high even when the device is on standby so that the image can be output immediately and immediately from the image forming apparatus. Therefore, there is a problem that energy consumption is large.

Japanese Patent Application Laid-Open No. 63-313182 discloses a method in which a heating element is provided on a ceramic substrate such as alumina to form a heating element, which is heated to heat a recording material through a thin film. It is proposed in the gazette.

[0005] Unlike a heating device such as a heat roller method, such a film heating type heating device uses a low-heat-capacity heating element or a thin fixing film that heats up quickly, so that the temperature of the heating element can be reduced in a short time. , So you can reduce your wait time (quick start, on demand)
Since there is no need to energize and heat the heating element while the image forming apparatus is on standby, there is an advantage that power can be saved.

FIG. 8 is a schematic sectional view of the film heating device 111, FIG. 9 is a schematic sectional view of a main part of the film heating device 111, and FIG. 10 is a schematic configuration diagram of the heating element 1 and temperature control.

The fixing film 3 is an endless heat-resistant film, and is externally fitted to a heating member support 2 which is a guide member of the fixing film 3 including the heating member 1. The inner peripheral length of the endless fixing film 3 is, for example, about 3 mm larger than the outer peripheral length of the heater support 2 including the heater 1. Therefore, the fixing film 3 is
The circumference is loosely fitted with a margin.

The fixing film 3 has a film thickness of 100 .mu.m or less, preferably 10 to 50 .mu.m, in order to enhance heat transfer, reduce heat capacity, and improve quick start performance.
m, heat-resistant single layer of PTFE, PFA, FEP, or polyimide, polyamideimide, PEE
K, PES, PTFE, PFA,
A composite layer film coated with FEP or the like can be used. In this embodiment, PTFE is applied to the outer peripheral surface of the polyimide.
A composite layer film having a total thickness of 60 μm coated with was used.

Reference numeral 1 denotes a heating element, which is made of alumina (Al ₂ O).
₃ ) An electric resistance material such as Ag / Pd (silver-palladium) is used as a heating resistor 12 on a heating substrate 11 which is a ceramic substrate such as ₃ ).
3 mm is applied and baked by screen printing or the like, and a protective layer 17 is coated thereon with glass, fluororesin or the like.

As shown by the heating element front surface in FIG. 10A and the heating element back surface in FIG. 10B, the heating element 1 has conductive patterns 15 and 16 of the heating element 12 and the heating element 12 of the heating element 12. Power supply electrode patterns 13 and 14, temperature detecting elements 24 such as thermistors, and conductive patterns 22.2 of temperature detecting elements 24
3. Through holes 20 and 21 penetrated from the back of heating element 1
The power supply electrode patterns 18 and 19 of the temperature detecting element 24 that conducts electricity to the conductive patterns 22 and 23 through the power supply patterns 22 and 23 are arranged. FIG. 10 shows an example of a heating device of an image forming apparatus of central reference sheet passing.

Further, 13.14, 15.16, 18.1
9, 22, and 23 are formed by applying and baking a conductive material such as Ag or Ag / Pd with a thickness of 10 to 30 μm by screen printing or the like in the same manner as the heating resistor 12.

In particular, the conductive pattern 2 of the temperature detecting element 24
An example of 2 · 23 is shown below.

Material: Ag alone or Ag / Pd, etc. Height: 10 to 30 [μm] Width: 0.5 to 1.0 [mm] 4 shown in FIG. 3 is a pressure roller as a rotating body for driving the fixing film 3 by forming a nip portion N with the nip portion N interposed therebetween. The pressing roller is composed of a cored bar 4a and a heat-resistant rubber 4b having good releasability such as silicon rubber. It is rotationally driven from the end of 4a by a driving means (not shown). Rotational force acts on the fixing film 3 by the frictional contact between the outer peripheral surface of the pressure roller 4 and the outer peripheral surface of the fixing film 3 at the nip portion N, and the inner surface of the fixing film 3 While being in close contact with the surface of the heating element 1 and sliding, the outer periphery of the heating element support 2 is rotated in the direction of arrow a at a peripheral speed substantially corresponding to the rotational peripheral speed of the pressing roller 4 (pressing roller drive method).

The temperature control of the heater 1 will be described below.

As shown in FIG. 10, a connector 31 for fixing and holding the heating element 1 to the heating element support 2 is attached to the power supply electrode patterns 13 and 14 of the heating element 1.
By the pressure springs 32, 32 as electrical contacts in 1,
The heating resistor 12 is connected to a power supply circuit including a power supply 34 and a triac 35 via a power supply wire 33.

The power supply electrode pattern 18 of the heating element 1
A connector 36 for fixing and holding the heating element 1 to the heating element support 2 is attached to the heating element 19, and a power supply wire 38 is provided by pressure springs 37 as electrical contacts in the connector 36.
, The temperature detecting element 24 is connected to the A / D converter 39 of the control system.

As the temperature information of the heating element 1, the thermistor voltage of the temperature detecting element 24 provided in the paper passing area of the recording material P is input to the A / D converter, and is taken into the CPU 40 as digital data. The CPU 40 controls the triac 35 based on the input digital data so as to control the temperature of the heating body to a predetermined constant temperature. As a control method, a method of controlling the applied voltage or current of the heating resistor 12 or controlling the energization time is employed. Methods for controlling the energization time include zero-crossing wave number control for controlling energization and non-energization for each half-wave of the power supply waveform, and phase control for controlling the phase angle of energization for each half-wave of the power supply waveform.

Conventionally, the heater substrate 11 of the heater 1 is made of a heat-resistant material such as alumina (Al ₂ O ₃ ) which is relatively inexpensive.
An electrically insulating, low heat capacity ceramic substrate was used.
However, due to the trend, it is required to increase the speed and shorten the wait time (quick start) of an image forming apparatus using an electrophotographic method such as a copying machine or a printer. There has been a need for a material that can replace the alumina substrate with excellent thermal conductivity that can supply heat to the pressure roller.

Therefore, the thermal conductivity is about 17 times higher than that of the alumina substrate, and the low thermal expansion coefficient, high strength, and light weight of AlN
An (aluminum nitride) substrate has been proposed as a material for the heating substrate 11 instead of the alumina substrate.

[0020]

Conventionally, as shown in FIG. 11, the heating resistor 12 of the heating element 1 on the bottom surface of the heating element insertion groove 2a which is the receiving surface of the heating element 1 of the heating element support 2 is provided. With a configuration in which a counterbore portion (step portion) 2b is provided in a corresponding portion to provide a non-contact portion between the heating body 1 and the heating body support 2,
By reducing the amount of heat of the heating element 12 of the heating element 1 taken away by the heating element support 2, the wait time for increasing the temperature of the heating element 1 is shortened, the power consumption of the heating element 12 is reduced, Further, the fixing property was improved.

However, the heating element 1 and the heating element support 2
The heat of the heating resistor 12 of the heating element 1 is not deprived by the heating element support 2 by the counterbore portion 2b which is a non-contact portion with the recording material P due to extremely thick paper or poor paper feeding. When a plurality of sheets of paper are fed one after another (double feed), the nip width of the nip portion N decreases at the end of the thick paper or the double fed feed of the recording material P, and the heat of the heating body 1 is taken by the pressure roller. However, the temperature of the heating element 1 locally rises excessively at the portion corresponding to the end of the cardboard or the multi-feed recording material P, and in the worst case, the heating element 1
However, there was a problem that the glass was broken (cracked).

The damage of the heating element 1 due to the cardboard or the double feed is as follows.
Rubber part 4 of pressure roller 4 to increase the thickness of rubber part 4b
By reducing the hardness of b, increasing the contact pressure between the heating element 1 and the pressure roller, or the like, the nip width of the nip portion N can be increased to a certain extent to avoid the problem. However, since the degree of freedom in design is reduced, further margin UP
Therefore, as shown in FIG. 12, the counterbore portion 2b on the bottom surface of the heating element fitting groove 2a of the heating element support 2 is eliminated, and the bottom surface of the 2a portion is made flat (flat). In the paper passing area, a counterbore portion 2c for a temperature detecting element, which is an escape groove for the temperature detecting element 24, and a through hole for a thermal fuse, which is a through hole for placing a temperature fuse 50 as a safety circuit in contact with the heating element 1. It has been proposed to use a heating element support 2 provided with 2d.

That is, on the bottom surface of the portion 2a, the counterbore portion and the through hole are arranged only in the paper passing area of the minimum size paper (paper passing area), and at least outside the paper passing area of the minimum size paper (non paper passing area). And a portion corresponding to the heating resistor 12 is flattened and brought into contact with the heating element 1 to remove the locally excessively heated heat at the end of the cardboard of the heating element 1 or the end of the multi-feed recording material P.
By dissipating heat to the heating element support 2, damage to the heating element 1 can be prevented.

Here, the thermal fuse 50 includes a heat generating resistor 12, a power source 34 and a triac 35 as a safety circuit.
The power supply circuit 33 is connected in series to a power supply wire 33, and as shown in FIG. 13, is pressed against the heater 1 by pressing means such as a spring (not shown). You. In order to ensure contact, it is preferable to apply heat-resistant grease or the like to a contact portion between the heating element 1 and the thermal fuse 50. For example, in the case where the CPU 40 breaks down due to a failure or the like, the temperature fuse 50 operating at an arbitrary rated operating temperature can surely prevent smoke and ignition.

Further, in this embodiment, as shown in FIG. 13, the through hole 2d is arranged in the heater support 2 so that the thermal fuse 50 and the heater 1 are arranged in contact with each other.
As shown in FIG. 14A, a non-contact arrangement through an air layer kept at a predetermined distance, and as shown in FIG. In the configuration in which the thermal fuse is arranged via the
By arbitrarily determining the rated operating temperature of 0, it is possible to operate as a safety circuit.

As described above, by flattening at least the bottom surface of the heating element insertion groove 2a of the heating element support 2 corresponding to the heating resistor 12 outside the paper passing area of the minimum size paper, the thick paper or recording medium is formed. It was possible to prevent the heating element 1 from being damaged by the double feeding of the material P.

However, due to the flattening described above, the fixing property is not good on the left and right sides of the heating element in the longitudinal direction (on the power supply electrode patterns 13 and 14 side of the heating resistor 12 and on the power supply electrode patterns 18 and 19 side of the temperature detecting element 24). The problem of uniformity occurred.

This problem will be described with reference to FIGS.

FIG. 15 is a schematic sectional view at the position G in FIG.
As shown in (a), since the conductive patterns 22 and 23 of the temperature detection element 24 are arranged, the heater support 2 and the conductive patterns 22 and 23 are in contact with each other. Since the heating element 1 is not in contact with the heating element substrate 11, the amount of heat of the heating element 1 taken away by the heating element support 2 is small. The side has good fixability.

On the other hand, FIG. 15B is a schematic cross-sectional view at the H position in FIG. As described above, since the heating body support 2 and the heating body substrate 11 of the heating body 1 are in contact with each other, a large amount of heat of the heating body 1 is removed by the heating body support 2,
The fixing property is poor on the side of the power supply electrode patterns 13 and 14 of the heating resistor 12.

FIG. 16 is an enlarged schematic sectional view of a main part of FIG.

As shown in FIG. 16, the direction of rotation of the film and the direction of conveyance of the recording material P are indicated by arrows a, the side where the recording material P is inserted into the nip N is the upstream side, and the recording material P is discharged from the nip N. The discharge side is the downstream side. The upstream jaw portion 2e of the heater support 2 and the heater 1 (the protective layer 1 on the surface side of the heater 1)
7), as shown in FIG. 16 (a) as an enlarged schematic cross-sectional view at a position G in FIG. 12 and FIG. 16 (b) as an enlarged schematic cross-sectional view at a position H in FIG. The height T2 at the position is G
It is higher than the height T1 at the position by the amount of the conductive patterns 22 and 23.

As for the fixing property, the smaller the height T, the better the fixing property, and the larger the height T, the worse the fixing property. This is because when the fixing film 3 externally fitted to the heating element support 2 comes into contact with the heating element 1 from the upstream side, the smaller the height T, the more the point of contact with the heating element 1 becomes. Therefore, the fixing film 3 is easily heated by the heating element 1 and the height T
Is larger, the point of contact with the heating element 1 is further downstream, so that the fixing film 3 is less likely to be heated by the heating element 1.

Normally, at least the upstream jaw portion 2e is set higher than the heating body substrate 11 so that the fixing film 3 is not rubbed and scraped by the edge of the heating body substrate 11 of the heating body 1. More preferably, the upstream jaw portion 2e is set to be equal to or higher than the surface of the protective layer 17 of the heating element 1.

Therefore, on the side of the power supply electrode patterns 18 and 19 shown in FIG. 16A, the conductive patterns 22 and 23 of the temperature detecting element 24 are arranged, and the height T1 between the upstream jaw 2e and the heater 1 is reduced. Good fixability due to small size. on the other hand,
On the side of the power supply electrode patterns 13 and 14 shown in FIG. 16B, the fixing property is poor because the height T2 between the upstream jaw 2e and the heating element 1 is larger than T1 by the conductive patterns 22 and 23. .

As described above, on the side of the heating element 1 where the conductive patterns 22 and 23 of the temperature detecting element 24 are provided, the fixing property is good and the conductive patterns 22 and 23 of the temperature detecting element 24 are good.
On the side where no heater is provided, the fixing property is poor, and heat is generated due to the contact area between the heater 1 and the heater support 2 and the right and left difference due to the height T between the heater 1 and the upstream jaw 2e of the heater support 2. A left-right difference in fixability occurs between the left and right in the longitudinal direction of the resistor 12,
The problem that the fixing property of the image becomes non-uniform occurs.

In particular, when an AlN (aluminum nitride) substrate having a thermal conductivity approximately 17 times higher than that of an alumina substrate is used, since the thermal conductivity of the heating substrate 11 is high, the conductivity of the temperature detecting element 24 is reduced. The difference in the amount of heat deprived from the heating element 1 to the heating element support 2 becomes greater between the side where the patterns 22 and 23 are present and the side where the patterns 22 and 23 are not present. Would.

Accordingly, it is an object of the present invention to prevent breakage of a heating member such as a very thick paper or a recording material P at the time of double feeding, and to have good and uniform heating characteristics over the entire region in the longitudinal direction of the heating member. Another object of the present invention is to provide a heating device and an image forming apparatus capable of heating an image.

[0039]

Means for Solving the Problems [1]: A heating element provided with a heating resistor and a temperature detecting element for generating heat by energizing a substrate, a support for the heating element, and sliding movement to the heating element A heating device that has a film and a pressurizing member that forms a nip by pressing against a heating body through the film, and heats the image by nipping and conveying a recording material carrying an image in the nip. The heating body is fitted into the heating body fitting groove provided in the heating body support, is held in contact with the bottom of the fitting groove, and the contact surface of the heating body is formed between the heating body and the heating body support. A heating device, comprising a height adjustment pattern for adjusting a contact area or a height between a film sliding surface of the heating element and a film sliding surface of the heating element support.

[2]: The bottom of the fitting groove of the heating element support is flat at least in an area outside the sheet passing area of the recording material of the minimum size and corresponding to the heating resistor. 1] The heating device according to the above.

[3] The heating device according to [1] or [2], wherein the height adjustment patterns are arranged in a dotted line or a staggered pattern.

[4]: A heating element provided with a heating resistor and a temperature detecting element that generate heat by energizing the substrate, a support for the heating element, a film that slides on the heating element, A pressure member that forms a nip by being in contact with a heating element through the nip, and heats the image by nipping and conveying a recording material bearing an image in the nip. The heating element and the heating element support are fitted into the heating element insertion groove provided in the support, are held in contact with the bottom of the insertion groove, and are in contact with the heating element of the heating element support. A height adjusting projection for adjusting a contact area between the heating element and a film sliding surface of the heating element and a film sliding surface of the heating element support.

[5] The heating device according to [4], wherein the height adjusting projections are arranged in a dotted line or in a staggered manner.

[6]: The image on the recording material is an unfixed toner image, and the toner image is fixed on the recording material by heating the toner image, [1] to [5]. Item 2. The heating device according to item 1.

[7] In an image forming apparatus having an image forming means for forming an image on a recording material and an image heating means for heating the image on the recording material, the image heating means may be any one of [1] to [ [6] An image forming apparatus comprising the image heating device according to any one of [1] to [6].

<Operation> That is, by arranging a height adjustment pattern on the heating element or a height adjustment projection on the heating element support, the heating element supports the heating element on the left and right sides in the longitudinal direction of the heating resistor. By making the contact area with the body substantially the same, making the heat release amount of the heating body to the heating body support substantially the same, and making the height of the heating body and the upstream jaw portion of the heating body support substantially the same, The fixing property can be made substantially uniform on the left and right sides in the longitudinal direction of the heating resistor.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> FIGS.
A first embodiment according to the present invention will be described with reference to FIG.

In this embodiment, the bottom surface of the heating element insertion groove 2a of the heating element support 2 is flattened at least outside the paper passing area of the minimum size paper, and the heating element is brought into contact with the heating element 1, so that extremely thick paper or multi-feeding is performed. By radiating the heat of the heating body 1 locally excessively heated at the end of the recording material P to the heating body support 2,
This is a heating device for preventing the heating body 1 from being damaged, and achieves the above object by disposing a height adjustment pattern 60 (dummy pattern) on the heating body 1. Since other configurations are the same as those of the apparatus shown in FIGS. 8 to 10, the same elements are denoted by the same reference numerals and the description thereof will not be repeated.

Specifically, as shown in the schematic configuration diagram of FIG. 1, the conductive pattern of the temperature detecting element 24 is provided on the side of the temperature detecting element 24 on the heating body substrate 11 of the heating body 1 (the back side of the heating body 1). By arranging the height adjustment pattern 60 (dummy pattern) having substantially the same configuration as that of the heating resistors 22 and 23, as shown in a schematic cross-sectional view of the main part of FIG. (G position, H position), the contact area of the heating element 1 with the heating element support 2 is set to be substantially the same, and the heat release amount of the heating element 1 to the heating element support 2 is set to be substantially the same. As shown in the enlarged schematic cross-sectional view of the main part of FIG. 3, the height T of the heating body 1 and the height T of the upstream jaw 2e of the heating body support 2 are substantially the same, When the fixing film 3 comes into contact with the heating element 1 from the upstream side, By the cement substantially the same, it can be made substantially uniform fixing performance in the longitudinal direction of the left and right.

Further, by arbitrarily setting the configurations of the conductive patterns 22 and 23 and the height adjustment pattern 60 in accordance with the heating device, the conventional counterbore portion (step portion) 2 b
Similarly to the above, the non-contact portion between the heater substrate 11 and the heater support 2 can be appropriately set, and the amount of heat of the heating resistor 12 of the heater 1 taken away by the heater support 2 is adjusted. Therefore, it is possible to set such that the wait time for increasing the temperature of the heating element 1 can be shortened, the power consumption of the heating resistor 12 can be reduced, and the fixing property can be improved at the same time.

The height adjusting pattern 60 may be made of any material. However, if the same material, line width and height as the conductive patterns 22 and 23 are used, the heating element 1 can be discharged to the heating element support 2. Heat quantity and upstream jaw 2e of heating body 1 and heating body support 2
Is the same on the left and right sides of the heating resistor 12,
More preferred. Further, the material is changed to the conductive pattern 22.2.
3, the height adjustment pattern 60 can be printed simultaneously with the screen printing of the conductive patterns 22 and 23 only by changing the mask shape at the time of screen printing of the conductive patterns 22 and 23. This has the advantage that the number of manufacturing steps is not increased and the cost is small.

Actually, in an image forming apparatus of A4.8 sheets / min (process speed of about 50 mm / sec), the heating substrate 11 is 270 mm long, 7 mm wide and 0 mm thick.
6mm alumina (Al ₂ O ₃ ) substrate and AlN
Using a substrate, as shown in FIG.
Same configuration as 3 [Material (Ag + Pd), height (20μ)
m), line width (0.8 mm)], height adjustment pattern 60
Was placed on the heating element substrate 11 of the heating element 1 (excluding the portion corresponding to the through hole 2d for the thermal fuse), and the fixing property was confirmed. The print image output from the image forming apparatus is
Substantially uniform fixability was exhibited throughout the image.

Further, damage due to local excessive heating of the heating element 1 at the end of the recording material P at the time of thick paper or double feeding may be caused by the conductive pattern 2.
The overheat is locally dispersed in the longitudinal direction along the 2 · 23 and the height adjustment pattern 60, and the overheat is reduced by dissipating the dispersed heat to the heater support 2. Further, the mechanical strength of the conductive patterns 22 and 23 and the height adjustment pattern 60 is added to the heater 1,
By increasing the mechanical strength against breakage, the breakage preventing effect of the heater 1 was also improved.

<Second Embodiment> A second embodiment according to the present invention will be described with reference to FIG.

In the present embodiment, as an application example of the height adjustment pattern, as shown in FIG. 4A, by arranging the height adjustment pattern 61 in a dotted line, the same effect as in the first embodiment can be obtained. In addition, the material cost of the height adjustment pattern is reduced, and the cost can be reduced.

In the case where the intermittent height adjustment pattern 61 is used as described above, and there is a portion having a pattern and a portion not having the pattern in the recording material conveyance direction, the heat radiation amount of the heater 1 to the heater support 2 is reduced. Differences may occur.

Therefore, when the dotted height adjustment patterns are arranged in a staggered manner as in the height adjustment pattern 62 shown in FIG. 4B, the material cost of the height adjustment patterns is reduced, and the cost is reduced. Can be realized, and at the same time, uniformity of the fixing property can be realized, which is more preferable.

Actually, in an image forming apparatus of A4.8 sheets / min (process speed of about 50 mm / sec), alumina (Al ₂ O) having a length of 270 mm, a width of 7 mm and a thickness of 0.6 mm was used as the heating substrate 11. ₃ ) Substrate and Al
Using an N substrate, as shown in FIG. 4A, the same configuration as the conductive patterns 22 and 23 [material (Ag + Pd), height (2
0 μm), the line width (0.8 mm)], the height adjustment pattern 61 and the height adjustment pattern 62,
m, the interval m = 10 mm, and the staggered interval k = 5 mm, the heater 1 was placed on the heater substrate 11 (excluding the portion corresponding to the through hole 2 d for the thermal fuse), and the fixing property was confirmed. The fixability on the left and right sides of the resistor 12 is almost the same, and the print image output from the image forming apparatus is:
Substantially uniform fixability was exhibited throughout the image.

As described above, according to the present embodiment, by setting the dotted line height adjustment pattern arbitrarily in accordance with the heating device, it is possible to prevent a difference in fixability from right to left, and at the same time, to prevent thick paper or a recording material during double feeding. The same effect as in the first embodiment can be maintained for damage due to local excessive temperature rise of the heating element 1 at the P end, and further, similar to the conventional counterbore (stepped portion) 2b. The non-contact portion between the heating body substrate 11 and the heating body support 2 can be set appropriately, and the heating resistor 12 of the heating body 1 can be set.
The amount of heat taken by the heater support 2 can be adjusted, so that the wait time for increasing the temperature of the heater 1 can be shortened, the power consumption of the heating resistor 12 can be reduced, and the fixing property can be improved. At the same time, a setting that satisfies it becomes possible.

<Third Embodiment> A third embodiment according to the present invention will be described with reference to FIG.

The first embodiment and the second embodiment are as follows.
The placement of the height adjustment pattern on the heating element 1 prevents the occurrence of a difference in fixability between left and right. However, in the present embodiment, the height adjustment projection 70 is provided on the bottom surface of the heating element fitting groove 2a of the heating element support 2. Was provided.

More specifically, as shown in FIG. 5, the temperature detecting element 24 is provided on the bottom surface of the heating element fitting groove 2a of the heating element support 2.
A height adjusting convex portion 70 having substantially the same line width and height as the conductive patterns 22 and 23 is formed. As shown in FIG. In the above, the contact area of the heating element 1 with the heating element support 2 is substantially the same, and the heat release amount of the heating element 1 to the heating element support 2 is substantially the same. The height T of the fixing film 3 is substantially the same as that of the upstream jaw portion 2e, and the point at which the fixing film 3 comes into contact with the heating body 1 from the upstream side is substantially the same. Can make the fixability substantially uniform.

Actually, in an image forming apparatus of A4.8 sheets / minute (process speed about 50 mm / sec), alumina (Al ₂ O) having a length of 270 mm, a width of 7 mm and a thickness of 0.6 mm was used as the heating substrate 11. ₃ ) Substrate and Al
Using an N substrate, as shown in FIG.
23 (height (20 μm), line width (0.8 m
m)], the height adjusting protrusion 70 (the material is the same as the material of the bottom surface of the heating body fitting groove 2a of the heating body support 2) is formed on the bottom surface of the heating body fitting groove 2a of the heating body support 2. It was confirmed that the fixing properties were almost the same on the left and right sides of the heating resistor 12, and the print image output from the image forming apparatus was:
Substantially uniform fixability was exhibited throughout the image.

In this embodiment, as a simple method, the material of the height adjusting projection 70 is the same as that of the bottom surface of the heating element fitting groove 2a of the heating element support 2 and is integrated with the heating element support 2. However, a metal-based material similar to the material of the conductive patterns 22 and 23 was applied on the bottom surface of the heating element fitting groove 2a,
A configuration in which a height adjusting protrusion is formed may be used.

As described above, by setting the height adjusting convex portion 70 arbitrarily according to the heating device, a difference in fixability between left and right can be prevented, and at the same time, the end portion of the recording material P at the time of thick paper or double feeding can be prevented. The same effect as that of the first embodiment can be maintained even when the heating element 1 is damaged due to local excessive temperature rise. Further, similarly to the conventional counterbore portion (step portion) 2b, the heating element substrate 11
The non-contact portion between the heating element support 2 and the heating element support 2 can be set appropriately, and the heat of the heating resistor 12 of the heating element 1 is
Can be adjusted so that the wait time for increasing the temperature of the heating element 1 can be shortened, the power consumption of the heating resistor 12 can be reduced, and the fixing property can be improved at the same time. Becomes

The first to third embodiments may be used in any combination.

The configuration of the height adjusting pattern and the height adjusting convex portion is determined by the position, material, height, line width,
The shape may be arbitrarily set so that the fixability is uniform in the left and right directions in the longitudinal direction.

Although the above embodiment has been described with reference to the central reference sheet passing, the present invention can be similarly applied to an image forming apparatus of one side reference sheet passing, and the effects are the same.

Furthermore, in the above-described embodiment, the height adjustment pattern is not arranged at the portion corresponding to the thermal fuse through hole 2d.
A height adjustment pattern may be arranged at a position corresponding to d. Needless to say, the present invention can be applied to a configuration without the through hole 2d for the thermal fuse.

<Example of Image Forming Apparatus> FIG. 7 is a schematic sectional view showing an example of an image forming apparatus 100 using a conventional electrophotographic method.

In FIG. 7, the photosensitive drum 101 as a latent image carrier rotates in the direction of arrow A, and
Is charged uniformly by a charging roller 102 for charging, and an electrostatic latent image is formed on the surface of the photosensitive drum 101 by a laser beam 103 serving as an exposure unit for writing the electrostatic latent image. This electrostatic latent image is transferred to the developing device 104
Is developed by the developing sleeve 106 carrying the toner t. Here, the recording material P is taken out of the paper feeding cassette 107, and is introduced into the nip portion between the transfer roller 108 and the photosensitive drum 101 at a predetermined timing, and the toner image on the photosensitive drum 101 is transferred onto the recording material P. Is transferred to

After the transfer process, the transfer residual toner on the photosensitive drum 101 is removed from the photosensitive drum 101 by the cleaning blade 109 and the cleaning device 11
Collected to 0. After the cleaning step, the photosensitive drum 101 is subjected to an image forming process (charging → exposure → development →
By repeating (transfer → cleaning), an unfixed toner image is formed on the recording material P.

On the other hand, the recording material P carrying the unfixed toner image
Is introduced into the heating device 111 shown in the first, second or third embodiment, and is pressed and heated to fix the toner image on the recording material P.

[0074]

As described above, according to the present invention,
A heating device and an image forming apparatus capable of preventing damage to a heating element such as a thick paper or a recording material during double feeding, and having uniform heating characteristics over the entire longitudinal direction of the heating element and capable of heating an image in a good and uniform manner. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a film heating device according to a first embodiment.

FIG. 2 is a schematic cross-sectional view of a main part of the film heating device according to the first embodiment.

FIG. 3 is an enlarged schematic cross-sectional view of a main part of the film heating device according to the first embodiment.

FIG. 4 is a schematic configuration diagram of a main part of a film heating device according to a second embodiment.

FIG. 5 is a schematic configuration diagram of a main part of a film heating device according to a third embodiment.

FIG. 6 is a schematic sectional view of a main part of a film heating device according to a third embodiment.

FIG. 7 is a schematic cross-sectional view illustrating an example of an image forming apparatus.

FIG. 8 is a schematic sectional view of a film heating device.

FIG. 9 is a schematic sectional view of a main part of a film heating device.

FIG. 10 is a schematic configuration diagram of a heating element and temperature control.

FIG. 11 is a schematic configuration diagram of a conventional film heating apparatus.

FIG. 12 is a schematic configuration diagram of a heater support.

FIG. 13 is a schematic sectional view of a safety circuit (thermal fuse).

FIG. 14 is a schematic sectional view of a safety circuit (thermal fuse).

FIG. 15 is a schematic sectional view of a main part of a conventional film heating apparatus.

FIG. 16 is an enlarged schematic sectional view of a main part of a conventional film heating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating body 2 Heating body support 2a Heating body fitting groove part 2b Counterbore part (step part) 2c Counterbore part for temperature detection element 2d Through hole for temperature fuse 2e Upstream jaw part 3 Fixing film (heat-resistant film) 4 Pressure roller 4a Core 4b Rubber part (heat-resistant rubber) 11 Heating substrate 12 Heating resistor 13, 14 Power supply electrode pattern 15, 16 Conductive pattern 17 Protective layer 18, 19 Power supply electrode pattern 20, 21 Through hole 22, 23 Conductivity of temperature detecting element Pattern 24 temperature detecting element 31 connector 32 pressure spring 33 power supply wire 34 power supply 35 triac 36 connector 37 pressure spring 38 power supply wire 39 A / D converter 50 temperature fuse 60, 61, 62 height adjustment pattern 70 height adjustment protrusion DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Photosensitive drum 102 Charging low 103 Laser light 104 Developing device 106 Developing sleeve 107 Paper feed cassette 108 Transfer roller 110 Cleaning device 111 Film heating device N Nip P Recording material t Toner k Height adjustment pattern Staggered interval l Height adjustment pattern length m Height adjustment pattern interval

Claims (7)

[Claims] 1. A heating element provided with a heating resistor and a temperature detecting element which generate heat by energizing a substrate, a support for the heating element, a film slidably moving on the heating element, and A heating member that has a pressure member that forms a nip by being pressed against a heating body, wherein the heating element sandwiches and conveys a recording material bearing an image in the nip and heats the image; Is fitted in the heating element fitting groove provided in the heating element, and is held in contact with the bottom of the fitting groove. The contact area between the heating element and the heating element support or the film of the heating element is provided on the contact surface of the heating element. A heating device, comprising a height adjustment pattern for adjusting the height between a sliding surface and a film sliding surface of a heater support. 2. A bottom surface of the fitting groove of the heating body support is flat at least in a region outside a paper passing area of a minimum-size recording material and corresponding to a heating resistor. A heating device as described. 3. The heating device according to claim 1, wherein the height adjustment patterns are arranged in a dotted line or in a staggered manner. 4. A heating element provided with a heating resistor and a temperature detecting element for generating heat by energizing a substrate, a support for the heating element, a film sliding on the heating element, and A heating member that has a pressure member that forms a nip by being pressed against a heating body, wherein the heating element sandwiches and conveys a recording material bearing an image in the nip and heats the image; The heater is inserted into the heater insertion groove provided in the heater, and is held in contact with the bottom of the insertion groove. The contact surface of the heater support with the heater is formed between the heater and the heater support. A heating device, comprising a height adjusting protrusion for adjusting a contact area or a height between a film sliding surface of the heating element and a film sliding surface of the heating element support. 5. The heating device according to claim 4, wherein the height adjusting projections are arranged in a dotted line or in a staggered manner. 6. The image forming apparatus according to claim 1, wherein the image on the recording material is an unfixed toner image, and the toner image is fixed on the recording material by heating. Heating equipment. 7. An image forming apparatus comprising: an image forming unit for forming an image on a recording material; and an image heating unit for heating the image on the recording material, wherein the image heating unit is used as the image heating unit. An image forming apparatus comprising the image heating device according to claim 1.